v0.12.0-rc.2

clippy
Support to_alias_override/to_alias_fallback in Require trait (Luau)
2026-06-08 16:05:43 +00:00 · 2026-06-06 14:28:31 +01:00 · 2026-06-06 14:28:31 +01:00 · 2026-06-06 14:11:59 +01:00 · 2026-06-01 00:25:12 +01:00 · 2026-05-31 13:45:48 +01:00
159 changed files with 7164 additions and 2332 deletions
@@ -0,0 +1,68 @@
+name: Documentation (main)
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow only one concurrent deployment
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  build:
+    name: Build Documentation
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@main
+      - uses: dtolnay/rust-toolchain@nightly
+      - uses: Swatinem/rust-cache@v2
+
+      - name: Build documentation
+        env:
+          RUSTDOCFLAGS: "--cfg docsrs"
+        run: |
+          cargo +nightly doc --no-deps \
+            --features "lua55,vendored,async,send,serde,macros,anyhow,userdata-wrappers"
+
+      - name: Create index redirect
+        run: |
+          echo '<!DOCTYPE html>
+          <html>
+            <head>
+              <meta charset="utf-8">
+              <title>Redirecting to mlua documentation</title>
+              <meta http-equiv="refresh" content="0; URL=mlua/index.html">
+              <link rel="canonical" href="mlua/index.html">
+            </head>
+            <body>
+              <p>Redirecting to <a href="mlua/index.html">mlua documentation</a>...</p>
+            </body>
+          </html>' > target/doc/index.html
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v4
+        with:
+          path: target/doc
+
+  deploy:
+    name: Deploy to GitHub Pages
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4
@@ -9,7 +9,7 @@ jobs:
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest]
        rust: [stable]
-        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
+        lua: [lua55, lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
        include:
          - os: ubuntu-latest
            target: x86_64-unknown-linux-gnu
@@ -31,35 +31,19 @@ jobs:
          cargo build --features "${{ matrix.lua }},vendored,async,serde,macros,anyhow,userdata-wrappers,send"
        shell: bash
      - name: Build ${{ matrix.lua }} pkg-config
-        if: ${{ matrix.os == 'ubuntu-latest' }}
+        if: ${{ matrix.os == 'ubuntu-latest' && matrix.lua != 'lua55' }}
        run: |
          sudo apt-get update
          sudo apt-get install -y --no-install-recommends liblua5.4-dev liblua5.3-dev liblua5.2-dev liblua5.1-0-dev libluajit-5.1-dev
          cargo build --features "${{ matrix.lua }}"

-  build_aarch64_cross_macos:
-    name: Cross-compile to aarch64-apple-darwin
-    runs-on: macos-latest
-    needs: build
-    strategy:
-      matrix:
-        lua: [lua54, lua53, lua52, lua51, luajit]
-    steps:
-      - uses: actions/checkout@main
-      - uses: dtolnay/rust-toolchain@stable
-        with:
-          toolchain: stable
-          target: aarch64-apple-darwin
-      - name: Cross-compile
-        run: cargo build --target aarch64-apple-darwin --features "${{ matrix.lua }},vendored,async,send,serde,macros,anyhow,userdata-wrappers"
-
  build_aarch64_cross_ubuntu:
    name: Cross-compile to aarch64-unknown-linux-gnu
    runs-on: ubuntu-latest
    needs: build
    strategy:
      matrix:
-        lua: [lua54, lua53, lua52, lua51, luajit]
+        lua: [lua55, lua54, lua53, lua52, lua51, luajit]
    steps:
      - uses: actions/checkout@main
      - uses: dtolnay/rust-toolchain@stable
@@ -81,7 +65,7 @@ jobs:
    needs: build
    strategy:
      matrix:
-        lua: [lua54, lua53, lua52, lua51]
+        lua: [lua55, lua54, lua53, lua52, lua51]
    steps:
      - uses: actions/checkout@main
      - uses: dtolnay/rust-toolchain@stable
@@ -105,7 +89,7 @@ jobs:
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest]
        rust: [stable, nightly]
-        lua: [lua54, lua53, lua52, lua51, luajit, luajit52, luau, luau-jit, luau-vector4]
+        lua: [lua55, lua54, lua53, lua52, lua51, luajit, luajit52, luau, luau-jit, luau-vector4]
        include:
          - os: ubuntu-latest
            target: x86_64-unknown-linux-gnu
@@ -126,8 +110,8 @@ jobs:
          cargo test --features "${{ matrix.lua }},vendored,async,serde,macros,anyhow,userdata-wrappers"
          cargo test --features "${{ matrix.lua }},vendored,async,serde,macros,anyhow,userdata-wrappers,send"
        shell: bash
-      - name: Run compile tests (macos lua54)
-        if: ${{ matrix.os == 'macos-latest' && matrix.lua == 'lua54' }}
+      - name: Run compile tests (macos lua55)
+        if: ${{ matrix.os == 'macos-latest' && matrix.lua == 'lua55' }}
        run: |
          TRYBUILD=overwrite cargo test --features "${{ matrix.lua }},vendored" --tests -- --ignored
          TRYBUILD=overwrite cargo test --features "${{ matrix.lua }},vendored,async,send,serde,macros" --tests -- --ignored
@@ -141,7 +125,7 @@ jobs:
      matrix:
        os: [ubuntu-latest]
        rust: [nightly]
-        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
+        lua: [lua55, lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
        include:
          - os: ubuntu-latest
            target: x86_64-unknown-linux-gnu
@@ -168,7 +152,7 @@ jobs:
      matrix:
        os: [ubuntu-latest]
        rust: [nightly]
-        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
+        lua: [lua55, lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
        include:
          - os: ubuntu-latest
            target: x86_64-unknown-linux-gnu
@@ -194,7 +178,7 @@ jobs:
      matrix:
        os: [ubuntu-latest, macos-latest]
        rust: [stable]
-        lua: [lua54, lua53, lua52, lua51, luajit]
+        lua: [lua55, lua54, lua53, lua52, lua51, luajit]
        include:
          - os: ubuntu-latest
            target: x86_64-unknown-linux-gnu
@@ -240,7 +224,7 @@ jobs:
    needs: build
    strategy:
      matrix:
-        lua: [lua54, lua53, lua52, lua51, luau]
+        lua: [lua55, lua54, lua53, lua52, lua51, luau]
    steps:
      - uses: actions/checkout@main
      - uses: dtolnay/rust-toolchain@stable
@@ -262,7 +246,7 @@ jobs:
    needs: build
    strategy:
      matrix:
-        lua: [lua54, lua53, lua52, lua51]
+        lua: [lua55, lua54, lua53, lua52, lua51]
    steps:
      - uses: actions/checkout@main
      - uses: dtolnay/rust-toolchain@stable
@@ -273,7 +257,7 @@ jobs:
        working-directory: ${{ runner.tool_cache }}
        run: |
          wasi_sdk=29
-          wasmtime=v39.0.0
+          wasmtime=v40.0.1

          curl -LO https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-$wasi_sdk/wasi-sdk-$wasi_sdk.0-x86_64-linux.tar.gz
          tar xf wasi-sdk-$wasi_sdk.0-x86_64-linux.tar.gz
@@ -306,7 +290,7 @@ jobs:
    runs-on: ubuntu-latest
    strategy:
      matrix:
-        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
+        lua: [lua55, lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
    steps:
      - uses: actions/checkout@main
      - uses: dtolnay/rust-toolchain@stable
@@ -1,17 +1,22 @@
-name: Typos Check
+name: Spelling Check
 on:
  pull_request:
  workflow_dispatch:

+permissions:
+  contents: read
+
+env:
+  CLICOLOR: 1
+
 jobs:
-  run:
+  spelling:
    name: Spell Check with Typos
    runs-on: ubuntu-latest
    steps:
    - name: Checkout Actions Repository
-      uses: actions/checkout@v4
-
+      uses: actions/checkout@main
    - name: Check spelling
-      uses: crate-ci/typos@master
+      uses: crate-ci/typos@v1.42.1
      with:
        config: ./typos.toml
@@ -1,3 +1,38 @@
+## v0.12.0-rc.2 (Jun 06, 2026)
+
+- Add `#[derive(UserData)]` and `#[mlua::userdata_impl]` macros
+- Support thread create/resume/yield callbacks for all Lua versions (including Luau)
+- Support `to_alias_override`/`to_alias_fallback` in `Require` trait (Luau)
+- Prevent `XRc` overflow when dropping `RawLua` with foreign Lua state
+- implement `Not` for `StdLib` (#699)
+- Fix `String::to_pointer` return NULL in Lua <5.4
+
+## v0.12.0-rc.1 (Apr 21, 2026)
+
+- Rust 2024 edition
+- Removed `Error::ToLuaConversionError` variant as it was unused (and not practically useful)
+- New modules to group data types: `chunk`, `debug`, `error`, `function`, `table`, `string`, `state`, `thread`, `userdata`, `luau`
+- Support `__todebugstring` metamethod for pretty formatting userdata value (for debugging)
+- New `MaybeSync` trait that is required for userdata types
+- Removed lifetime from `BorrowedStr` and `BorrowedBytes`
+- New `Thread` methods: `is_resumable`, `is_running`, `is_finished`, `is_error`
+- Added `Thread::state` to get raw Lua state pointer
+- Luau `TextRequirer` is renamed to `FsRequirer`
+- GC interface refactor: `Lua::gc_inc/Lua::gc_gen` is replaced with `gc_set_mode`
+- Added `GcIncParams` and `GcGenParams` for GC tuning
+- New `UserDataMethods::add_method_once` and `UserDataMethods::add_async_method_once`
+- Initial Luau integer64 type support
+- Changed interface of `Function::wrap/wrap_mut/wrap_async` to support any Error type
+- Changed `AnyUserData::type_name` to return `LuaString` instead
+- Added `UserDataOwned<T>` wrapper to take ownership of userdata `T` and implements `FromLua`
+
+## v0.11.6 (Jan 27, 2026)
+
+- Added Lua 5.5 support (`lua55` feature flag)
+- Luau updated to 0.705+
+- Added `AnyUserData::is_proxy` method to check if userdata is a proxy
+- Added `num_params`, `num_upvalues`, `is_vararg` to `FunctionInfo`
+
 ## v0.11.5 (Nov 22, 2025)

 - Luau updated to 0.701
@@ -1,9 +1,9 @@
 [package]
 name = "mlua"
-version = "0.11.5" # remember to update mlua_derive
+version = "0.12.0-rc.2" # remember to update mlua_derive
 authors = ["Aleksandr Orlenko <zxteam@pm.me>", "kyren <catherine@kyju.org>"]
-rust-version = "1.80.0"
-edition = "2021"
+rust-version = "1.88"
+edition = "2024"
 repository = "https://github.com/mlua-rs/mlua"
 documentation = "https://docs.rs/mlua"
 readme = "README.md"
@@ -11,12 +11,12 @@ keywords = ["lua", "luajit", "luau", "async", "scripting"]
 categories = ["api-bindings", "asynchronous"]
 license = "MIT"
 description = """
-High level bindings to Lua 5.4/5.3/5.2/5.1 (including LuaJIT) and Luau
+High level bindings to Lua 5.5/5.4/5.3/5.2/5.1 (including LuaJIT) and Luau
 with async/await features and support of writing native Lua modules in Rust.
 """

 [package.metadata.docs.rs]
-features = ["lua54", "vendored", "async", "send", "serde", "macros"]
+features = ["lua55", "vendored", "async", "send", "serde", "macros"]
 rustdoc-args = ["--cfg", "docsrs"]

 [workspace]
@@ -26,6 +26,7 @@ members = [
 ]

 [features]
+lua55 = ["ffi/lua55"]
 lua54 = ["ffi/lua54"]
 lua53 = ["ffi/lua53"]
 lua52 = ["ffi/lua52"]
@@ -41,7 +42,7 @@ async = ["dep:futures-util"]
 send = ["error-send"]
 error-send = []
 serde = ["dep:serde", "dep:erased-serde", "dep:serde-value", "bstr/serde"]
-macros = ["mlua_derive/macros"]
+macros = ["mlua_derive/macros", "dep:inventory"]
 anyhow = ["dep:anyhow", "error-send"]
 userdata-wrappers = ["parking_lot/send_guard"]

@@ -49,7 +50,7 @@ userdata-wrappers = ["parking_lot/send_guard"]
 serialize = ["serde"]

 [dependencies]
-mlua_derive = { version = "=0.11.0", optional = true, path = "mlua_derive" }
+mlua_derive = { version = "=0.12.0-rc.1", optional = true, path = "mlua_derive" }
 bstr = { version = "1.0", features = ["std"], default-features = false }
 either = "1.0"
 num-traits = { version = "0.2.14" }
@@ -60,10 +61,10 @@ erased-serde = { version = "0.4", optional = true }
 serde-value = { version = "0.7", optional = true }
 parking_lot = { version = "0.12", features = ["arc_lock"] }
 anyhow = { version = "1.0", optional = true }
-rustversion = "1.0"
+inventory = { version = "0.3", optional = true }
 libc = "0.2"

-ffi = { package = "mlua-sys", version = "0.9.0", path = "mlua-sys" }
+ffi = { package = "mlua-sys", version = "0.11.0-rc.1", path = "mlua-sys" }

 [dev-dependencies]
 trybuild = "1.0"
@@ -77,10 +78,10 @@ static_assertions = "1.0"
 hyper = { version = "1.2", features = ["full"] }
 hyper-util = { version = "0.1.3", features = ["full"] }
 http-body-util = "0.1.1"
-reqwest = { version = "0.12", features = ["json"] }
+reqwest = { version = "0.13", features = ["json"] }
 tempfile = "3"
-criterion = { version = "0.7", features = ["async_tokio"] }
-rustyline = "17.0"
+criterion = { version = "0.8", features = ["async_tokio"] }
+rustyline = "18.0"
 tokio = { version = "1.0", features = ["full"] }

 [lints.rust]
@@ -17,10 +17,12 @@
 [Benchmarks]: https://github.com/khvzak/script-bench-rs
 [FAQ]: FAQ.md

+## The main branch is the development version of `mlua`. Please see the [v0.11](https://github.com/mlua-rs/mlua/tree/v0.11) branch for the stable versions of `mlua`.
+
 `mlua` is a set of bindings to the [Lua](https://www.lua.org) programming language for Rust with a goal of providing a
 _safe_ (as much as possible), high level, easy to use, practical and flexible API.

-Started as an `rlua` fork, `mlua` supports Lua 5.4, 5.3, 5.2, 5.1 (including LuaJIT) and [Luau] and allows writing native Lua modules in Rust as well as using Lua in a standalone mode.
+Started as an `rlua` fork, `mlua` supports Lua 5.5, 5.4, 5.3, 5.2, 5.1 (including LuaJIT) and [Luau] and allows writing native Lua modules in Rust as well as using Lua in a standalone mode.

 `mlua` is tested on Windows/macOS/Linux including module mode in [GitHub Actions] on `x86_64` platforms and cross-compilation to `aarch64` (other targets are also supported).

@@ -36,6 +38,7 @@ WebAssembly (WASM) is supported through the `wasm32-unknown-emscripten` target f
 `mlua` uses feature flags to reduce the number of dependencies and compiled code, and allow choosing only the required set of features.
 Below is a list of the available feature flags. By default `mlua` does not enable any features.

+* `lua55`: enable Lua [5.5] support
 * `lua54`: enable Lua [5.4] support
 * `lua53`: enable Lua [5.3] support
 * `lua52`: enable Lua [5.2] support
@@ -55,6 +58,7 @@ Below is a list of the available feature flags. By default `mlua` does not enabl
 * `anyhow`: enable `anyhow::Error` conversion into Lua
 * `userdata-wrappers`: opt into `impl UserData` for `Rc<T>`/`Arc<T>`/`Rc<RefCell<T>>`/`Arc<Mutex<T>>` where `T: UserData`

+[5.5]: https://www.lua.org/manual/5.5/manual.html
 [5.4]: https://www.lua.org/manual/5.4/manual.html
 [5.3]: https://www.lua.org/manual/5.3/manual.html
 [5.2]: https://www.lua.org/manual/5.2/manual.html
@@ -123,7 +127,7 @@ my_project $ LUA_LIB=$HOME/tmp/lua-5.2.4/src LUA_LIB_NAME=lua LUA_LINK=static ca
 Just enable the `vendored` feature and cargo will automatically build and link the specified Lua/LuaJIT version. This is the easiest way to get started with `mlua`.

 ### Standalone mode
-In standalone mode, `mlua` allows adding scripting support to your application with a gently configured Lua runtime to ensure safety and soundness.
+In standalone mode, `mlua` allows adding scripting support to your application with a properly configured Lua runtime to ensure safety and soundness.

 Add to `Cargo.toml`:

@@ -1,7 +1,7 @@
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::time::Duration;

-use criterion::{criterion_group, criterion_main, BatchSize, Criterion};
+use criterion::{BatchSize, Criterion, criterion_group, criterion_main};
 use tokio::runtime::Runtime;
 use tokio::task;

@@ -1,6 +1,6 @@
 use std::time::Duration;

-use criterion::{criterion_group, criterion_main, BatchSize, Criterion};
+use criterion::{BatchSize, Criterion, criterion_group, criterion_main};

 use mlua::prelude::*;

@@ -0,0 +1,149 @@
+Implements the [`UserData`] trait for a Rust type.
+
+This derive macro generates an implementation of [`UserData`] that exposes
+struct fields to Lua and integrates with `#[mlua::userdata_impl]` for
+registering methods.
+
+Named fields are exposed as readable and writable fields in Lua by default.
+Use `#[lua(...)]` on individual fields or methods to control how they are
+registered.
+
+```rust,ignore
+use mlua::{Lua, Result, UserData};
+
+#[derive(UserData)]
+struct Rectangle {
+    length: u32,
+    width: u32,
+}
+
+#[mlua::userdata_impl]
+impl Rectangle {
+    #[lua(infallible)]
+    fn new(length: u32, width: u32) -> Self {
+        Self { length, width }
+    }
+
+    #[lua(getter, name = "area", infallible)]
+    fn calculate_area(&self) -> u32 {
+        self.length * self.width
+    }
+
+    fn diagonal(&self) -> Result<f64> {
+        Ok(((self.length.pow(2) + self.width.pow(2)) as f64).sqrt())
+    }
+}
+```
+
+# Struct field attributes
+
+Each named field can be annotated with `#[lua(...)]`:
+
+| Attribute      | Description                                           |
+| -------------- | ----------------------------------------------------- |
+| `get`          | Expose a getter. The field becomes readable from Lua. |
+| `set`          | Expose a setter. The field becomes writable from Lua. |
+| `skip`         | Do not expose this field.                             |
+| `name = "..."` | Override the Lua-facing name for the field.           |
+
+If neither `get` nor `set` is specified, both are enabled.
+
+Fields exposed as readable (via `get` or by default) must implement `Clone`.
+The generated getter clones the field value when accessed from Lua.
+
+# Methods registration
+
+Use `#[mlua::userdata_impl]` on an `impl` block to register methods,
+metamethods, and constants. All public items in the block are registered
+automatically.
+
+## Method detection
+
+The receiver type determines how a method is registered:
+
+| Receiver    | Registration      |
+| ----------- | ----------------- |
+| `&self`     | `add_method`      |
+| `&mut self` | `add_method_mut`  |
+| `self`      | `add_method_once` |
+| None        | `add_function`    |
+
+A first parameter of type `&Lua` (or `&mlua::Lua`) is treated as the
+Lua state reference and passed automatically.
+
+## Method and constant attributes
+
+Each item in the impl block can be annotated with `#[lua(...)]`:
+
+| Attribute      | Applies to         | Description                                                                            |
+| -------------- | ------------------ | -------------------------------------------------------------------------------------- |
+| `skip`         | Methods, constants | Exclude this item from registration.                                                   |
+| `name = "..."` | Methods, constants | Override the Lua-facing name.                                                          |
+| `infallible`   | Methods            | Wrap the return value in `Ok(...)`.                                                    |
+| `getter`       | Methods            | Register as a field getter. Must take `&self` and no Lua-facing arguments.             |
+| `setter`       | Methods            | Register as a field setter. Must take `&[mut] self` and one value argument.            |
+| `field`        | Methods, constants | Register as a static field. Methods must take no receiver and no Lua-facing arguments. |
+| `meta`         | Methods, constants | Register as a metamethod. May be combined with `field` for meta static fields.         |
+
+At most one of `getter`, `setter`, `field` may be specified on a method.
+
+## Constants
+
+Constants in an `#[mlua::userdata_impl]` block are registered as static
+fields:
+
+```rust,ignore
+#[mlua::userdata_impl]
+impl MyType {
+    const VERSION: &str = "1.0";
+    const COUNT: u32 = 42;
+}
+```
+
+Use `#[lua(meta)]` on a constant to register it as a meta static field.
+
+## Metamethods
+
+Annotate a method with `#[lua(meta)]` to register it as a Lua metamethod.
+The metamethod name is inferred from the function name when it starts with
+`__`. Use `name = "..."` to specify the name explicitly.
+
+```rust,ignore
+#[mlua::userdata_impl]
+impl MyType {
+    #[lua(meta, infallible)]
+    fn __add(&self, other: &Self) -> Self { ... }
+
+    #[lua(meta, name = "__call", infallible)]
+    fn construct(lua: &Lua, value: u32) -> Self { ... }
+}
+```
+
+## Reference parameters
+
+Reference parameters in method signatures are automatically mapped to
+the appropriate callback wrapper types:
+
+| Parameter type | Callback type       |
+| -------------- | ------------------- |
+| `&str`         | `BorrowedStr`       |
+| `&[u8]`        | `BorrowedBytes`     |
+| `&T`           | `UserDataRef<T>`    |
+| `&mut T`       | `UserDataRefMut<T>` |
+
+## Async methods
+
+Async methods are supported and registered via the corresponding async
+variants (`add_async_method`, `add_async_method_mut`, etc.).
+
+# Limitations
+
+Generics are not supported. Wrap a generic type in a concrete newtype
+instead.
+
+Union types cannot derive `UserData`.
+
+Enum types are accepted but generate no field registrations. All method
+registration must be done via `#[mlua::userdata_impl]`.
+
+[`UserData`]: crate::UserData
@@ -0,0 +1,52 @@
+Create a type that implements [`AsChunk`] and can capture Rust variables.
+
+This macro allows to write Lua code directly in Rust code.
+
+Rust variables can be referenced from Lua using `$` prefix, as shown in the example below.
+User's Rust types needs to implement [`UserData`] or [`IntoLua`] traits.
+
+Captured variables are **moved** into the chunk.
+
+```rust
+use mlua::{Lua, Result, chunk};
+
+fn main() -> Result<()> {
+    let lua = Lua::new();
+    let name = "Rustacean";
+    lua.load(chunk! {
+        print("hello, " .. $name)
+    }).exec()
+}
+```
+
+## Syntax issues
+
+Since the Rust tokenizer will tokenize Lua code, this imposes some restrictions.
+The main thing to remember is:
+
+- Use double quoted strings (`""`) instead of single quoted strings (`''`).
+
+  (Single quoted strings only work if they contain a single character, since in Rust,
+  `'a'` is a character literal).
+
+- Using Lua comments `--` is not desirable in **stable** Rust and can have bad side effects.
+
+  This is because procedural macros have Line/Column information available only in
+  **nightly** Rust. Instead, Lua chunks represented as a big single line of code in stable Rust.
+
+  As workaround, Rust comments `//` can be used.
+
+Other minor limitations:
+
+- Certain escape codes in string literals don't work. (Specifically: `\a`, `\b`, `\f`, `\v`,
+  `\123` (octal escape codes), `\u`, and `\U`).
+
+  These are accepted: : `\\`, `\n`, `\t`, `\r`, `\xAB` (hex escape codes), and `\0`.
+
+- The `//` (floor division) operator is unusable, as its start a comment.
+
+Everything else should work.
+
+[`AsChunk`]: crate::chunk::AsChunk
+[`UserData`]: crate::UserData
+[`IntoLua`]: crate::IntoLua
@@ -0,0 +1,41 @@
+Registers Lua module entrypoint.
+
+You can register multiple entrypoints as required.
+
+```rust,ignore
+use mlua::{Lua, Result, Table};
+
+#[mlua::lua_module]
+fn my_module(lua: &Lua) -> Result<Table> {
+    let exports = lua.create_table()?;
+    exports.set("hello", "world")?;
+    Ok(exports)
+}
+```
+
+Internally in the code above the compiler defines C function `luaopen_my_module`.
+
+You can also pass options to the attribute:
+
+* name - name of the module, defaults to the name of the function
+
+```rust,ignore
+#[mlua::lua_module(name = "alt_module")]
+fn my_module(lua: &Lua) -> Result<Table> {
+    ...
+}
+```
+
+* skip_memory_check - skip memory allocation checks for some operations.
+
+In module mode, mlua runs in an unknown environment and cannot tell whether there are any memory
+limits or not. As a result, some operations that require memory allocation run in protected
+mode. Setting this attribute will improve performance of such operations with risk of having
+uncaught exceptions and memory leaks.
+
+```rust,ignore
+#[mlua::lua_module(skip_memory_check)]
+fn my_module(lua: &Lua) -> Result<Table> {
+    ...
+}
+```
@@ -1,6 +1,6 @@
 ## mlua v0.10 release notes

-The v0.10 version of mlua has goal to improve the user experience while keeping the same performance and safety guarantees.
+The v0.10 version of mlua has a goal to improve the user experience while keeping the same performance and safety guarantees.
 This document highlights the most notable features. For a full list of changes, see the [CHANGELOG].

 [CHANGELOG]: https://github.com/mlua-rs/mlua/blob/main/CHANGELOG.md
@@ -40,7 +40,7 @@ assert_eq!(lua.globals().get::<i32>("i")?, 20);

 Under the hood, to synchronize access to the Lua state, mlua uses [`ReentrantMutex`] which can be recursively locked by a single thread. Only one thread can execute Lua code at a time, but it's possible to share Lua values between threads.

-This has some performance penalties (about 10-20%) compared to the lock free mode. This flag is disabled by default and does not supported in module mode.
+This has some performance penalties (about 10-20%) compared to the lock free mode. This flag is disabled by default and is not supported in module mode.

 [`ReentrantMutex`]: https://docs.rs/parking_lot/latest/parking_lot/type.ReentrantMutex.html

@@ -144,7 +144,7 @@ The following `Scope` methods were changed:
 Instead, scope has comprehensive support for borrowed userdata: `create_any_userdata_ref`, `create_any_userdata_ref_mut`, `create_userdata_ref`, `create_userdata_ref_mut`.

 `UserDataRef` and `UserDataRefMut` are no longer acceptable for scoped userdata access as they require owned underlying data.
-In mlua v0.9 this can cause read-after-free bug in some edge cases.
+In mlua v0.9 this could cause a read-after-free bug in some edge cases.

 To temporarily borrow underlying data, the `AnyUserData::borrow_scoped` and `AnyUserData::borrow_mut_scoped` methods were introduced:

@@ -152,9 +152,9 @@ It will automatically trigger JIT compilation for new Lua chunks. To disable it,

 #### 1. Better error reporting

-When calling a Rust function from Lua and passing wrong arguments, previous mlua versions reported a error message without any context or reference to the particular argument.
+When calling a Rust function from Lua and passing wrong arguments, previous mlua versions reported an error message without any context or reference to the particular argument.

-In v0.9 it reports a error message with the argument index and expected type:
+In v0.9 it reports an error message with the argument index and expected type:

 ```rust
 let func = lua.create_function(|_, _a: i32| Ok(()))?;
@@ -327,7 +327,7 @@ Under the hood a new function `luaopen_alt_module` will be created for the Lua m

 - `skip_memory_check` - skip memory allocation checks for some operations.

-In module mode, mlua runs in unknown environment and cannot say are there any memory limits or not. As result, some operations that require memory allocation runs in
+In module mode, mlua runs in an unknown environment and cannot tell whether there are any memory limits or not. As a result, some operations that require memory allocation run in
 protected mode. Setting this attribute will improve performance of such operations with risk of having uncaught exceptions and memory leaks.

 #### Improved Windows target
@@ -336,7 +336,7 @@ In previous mlua versions, building a Lua module for Windows requires having Lua
 In contrast, on Linux and macOS, modules can be built without any external dependencies using the `-undefined=dynamic_lookup` linker flag.

 With Rust 1.71+ it's now possible to lift this restriction for Windows as well. You can build modules normally and they will be linked with
-`lua54.dll`/`lua53.dll`/`lua52.dll`/`lua51.dll` depending on the enabled Lua version.
+`lua5x.dll` depending on the enabled Lua version.

 You still need to have the dll although, linked to application where the module will be loaded.

@@ -5,7 +5,7 @@ use hyper::body::Incoming;
 use hyper_util::client::legacy::Client as HyperClient;
 use hyper_util::rt::TokioExecutor;

-use mlua::{chunk, ExternalResult, Lua, Result, UserData, UserDataMethods};
+use mlua::{ExternalResult, Lua, Result, UserData, UserDataMethods, chunk};

 struct BodyReader(Incoming);

@@ -1,4 +1,4 @@
-use mlua::{chunk, ExternalResult, Lua, LuaSerdeExt, Result, Value};
+use mlua::{ExternalResult, Lua, LuaSerdeExt, Result, Value, chunk};

 #[tokio::main(flavor = "current_thread")]
 async fn main() -> Result<()> {
@@ -11,7 +11,7 @@ use hyper::{Request, Response};
 use hyper_util::rt::TokioIo;
 use tokio::net::TcpListener;

-use mlua::{chunk, Error as LuaError, Function, Lua, String as LuaString, Table, UserData, UserDataMethods};
+use mlua::{Error as LuaError, Function, Lua, String as LuaString, Table, UserData, UserDataMethods, chunk};

 /// Wrapper around incoming request that implements UserData
 struct LuaRequest(SocketAddr, Request<Incoming>);
@@ -4,7 +4,7 @@ use std::net::SocketAddr;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::{TcpListener, TcpStream};

-use mlua::{chunk, BString, Function, Lua, UserData, UserDataMethods};
+use mlua::{BString, Function, Lua, UserData, UserDataMethods, chunk};

 struct LuaTcpStream(TcpStream);

@@ -1,7 +1,7 @@
 use std::f32;
 use std::iter::FromIterator;

-use mlua::{chunk, FromLua, Function, Lua, MetaMethod, Result, UserData, UserDataMethods, Value, Variadic};
+use mlua::{FromLua, Function, Lua, MetaMethod, Result, UserData, UserDataMethods, Value, Variadic, chunk};

 fn main() -> Result<()> {
    // You can create a new Lua state with `Lua::new()`. This loads the default Lua std library
@@ -10,6 +10,7 @@ crate-type = ["cdylib"]
 [workspace]

 [features]
+lua55 = ["mlua/lua55"]
 lua54 = ["mlua/lua54"]
 lua53 = ["mlua/lua53"]
 lua52 = ["mlua/lua52"]
@@ -1,45 +1,46 @@
-use mlua::{chunk, Lua, MetaMethod, Result, UserData};
+use mlua::{Lua, Result, UserData, chunk};

-#[derive(Default)]
+#[derive(Default, UserData)]
 struct Rectangle {
    length: u32,
    width: u32,
 }

-impl UserData for Rectangle {
-    fn add_fields<F: mlua::UserDataFields<Self>>(fields: &mut F) {
-        fields.add_field_method_get("length", |_, this| Ok(this.length));
-        fields.add_field_method_set("length", |_, this, val| {
-            this.length = val;
-            Ok(())
-        });
-        fields.add_field_method_get("width", |_, this| Ok(this.width));
-        fields.add_field_method_set("width", |_, this, val| {
-            this.width = val;
-            Ok(())
-        });
+#[mlua::userdata_impl]
+impl Rectangle {
+    const NAME: &str = "Rectangle";
+
+    #[lua(infallible)]
+    fn new(length: u32, width: u32) -> Self {
+        Self { length, width }
    }

-    fn add_methods<M: mlua::UserDataMethods<Self>>(methods: &mut M) {
-        methods.add_method("area", |_, this, ()| Ok(this.length * this.width));
-        methods.add_method("diagonal", |_, this, ()| {
-            Ok((this.length.pow(2) as f64 + this.width.pow(2) as f64).sqrt())
-        });
+    #[lua(getter, name = "area", infallible)]
+    fn calculate_area(&self) -> u32 {
+        self.length * self.width
+    }

-        // Constructor
-        methods.add_meta_function(MetaMethod::Call, |_, ()| Ok(Rectangle::default()));
+    fn diagonal(&self) -> Result<f64> {
+        Ok((self.length.pow(2) as f64 + self.width.pow(2) as f64).sqrt())
+    }
+
+    // Constructor via `__call` metamethod
+    #[lua(meta, infallible)]
+    fn __call(length: u32, width: u32) -> Self {
+        Rectangle::new(length, width)
    }
 }

 fn main() -> Result<()> {
    let lua = Lua::new();
-    let rectangle = Rectangle::default();
+    lua.globals().set("Rectangle", lua.create_proxy::<Rectangle>()?)?;
    lua.load(chunk! {
-        local rect = $rectangle()
-        rect.width = 10
-        rect.length = 5
-        assert(rect:area() == 50)
-        assert(rect:diagonal() - 11.1803 < 0.0001)
+        local rect = Rectangle(10, 5)
+        rect.width = rect.width + 5
+        rect.length = rect.length + 5
+        assert(rect.NAME == "Rectangle")
+        assert(rect.area == 150)
+        assert(math.floor(rect:diagonal()) == 18)
    })
    .exec()
 }
@@ -1,9 +1,9 @@
 [package]
 name = "mlua-sys"
-version = "0.9.0"
+version = "0.11.0-rc.1"
 authors = ["Aleksandr Orlenko <zxteam@pm.me>"]
-rust-version = "1.71"
-edition = "2021"
+rust-version = "1.88"
+edition = "2024"
 repository = "https://github.com/mlua-rs/mlua"
 documentation = "https://docs.rs/mlua-sys"
 readme = "README.md"
@@ -12,14 +12,15 @@ license = "MIT"
 links = "lua"
 build = "build/main.rs"
 description = """
-Low level (FFI) bindings to Lua 5.4/5.3/5.2/5.1 (including LuaJIT) and Luau
+Low level (FFI) bindings to Lua 5.5/5.4/5.3/5.2/5.1 (including LuaJIT) and Luau
 """

 [package.metadata.docs.rs]
-features = ["lua54", "vendored"]
+features = ["lua55", "vendored"]
 rustdoc-args = ["--cfg", "docsrs"]

 [features]
+lua55 = []
 lua54 = []
 lua53 = []
 lua52 = []
@@ -34,14 +35,15 @@ external = []
 module = []

 [dependencies]
+libc = "0.2"

 [build-dependencies]
 cc = "1.0"
 cfg-if = "1.0"
 pkg-config = "0.3.17"
-lua-src = { version = ">= 548.1.0, < 548.2.0", optional = true }
-luajit-src = { version = ">= 210.6.0, < 210.7.0", optional = true }
-luau0-src = { version = "0.17.0", optional = true }
+lua-src = { version = ">= 550.1.0, < 550.2.0", optional = true }
+luajit-src = { version = ">= 210.7.0, < 210.8.0", optional = true }
+luau0-src = { version = "0.20.0", optional = true }

 [lints.rust]
 unexpected_cfgs = { level = "allow", check-cfg = ['cfg(raw_dylib)'] }
@@ -1,8 +1,9 @@
 # mlua-sys

-Low level (FFI) bindings to Lua 5.4/5.3/5.2/5.1 (including LuaJIT) and [Luau].
+Low level (FFI) bindings to Lua 5.5/5.4/5.3/5.2/5.1 (including [LuaJIT]) and [Luau].

 Intended to be consumed by the [mlua] crate.

+[LuaJIT]: https://github.com/LuaJIT/LuaJIT
 [Luau]: https://github.com/luau-lang/luau
 [mlua]: https://crates.io/crates/mlua
@@ -31,18 +31,16 @@ pub fn probe_lua() {

    // Find using `pkg-config`

+    #[cfg(feature = "lua55")]
+    let (incl_bound, excl_bound, alt_probe, ver) = ("5.5", "5.6", ["lua5.5", "lua-5.5", "lua55"], "5.5");
    #[cfg(feature = "lua54")]
-    let (incl_bound, excl_bound, alt_probe, ver) =
-        ("5.4", "5.5", ["lua5.4", "lua-5.4", "lua54"], "5.4");
+    let (incl_bound, excl_bound, alt_probe, ver) = ("5.4", "5.5", ["lua5.4", "lua-5.4", "lua54"], "5.4");
    #[cfg(feature = "lua53")]
-    let (incl_bound, excl_bound, alt_probe, ver) =
-        ("5.3", "5.4", ["lua5.3", "lua-5.3", "lua53"], "5.3");
+    let (incl_bound, excl_bound, alt_probe, ver) = ("5.3", "5.4", ["lua5.3", "lua-5.3", "lua53"], "5.3");
    #[cfg(feature = "lua52")]
-    let (incl_bound, excl_bound, alt_probe, ver) =
-        ("5.2", "5.3", ["lua5.2", "lua-5.2", "lua52"], "5.2");
+    let (incl_bound, excl_bound, alt_probe, ver) = ("5.2", "5.3", ["lua5.2", "lua-5.2", "lua52"], "5.2");
    #[cfg(feature = "lua51")]
-    let (incl_bound, excl_bound, alt_probe, ver) =
-        ("5.1", "5.2", ["lua5.1", "lua-5.1", "lua51"], "5.1");
+    let (incl_bound, excl_bound, alt_probe, ver) = ("5.1", "5.2", ["lua5.1", "lua-5.1", "lua51"], "5.1");
    #[cfg(feature = "luajit")]
    let (incl_bound, excl_bound, alt_probe, ver) = ("2.0.4", "2.2", [], "JIT");

@@ -54,9 +52,7 @@ pub fn probe_lua() {

    if lua.is_err() {
        for pkg in alt_probe {
-            lua = pkg_config::Config::new()
-                .cargo_metadata(true)
-                .probe(pkg);
+            lua = pkg_config::Config::new().cargo_metadata(true).probe(pkg);

            if lua.is_ok() {
                break;
@@ -1,6 +1,9 @@
 #![allow(dead_code)]

 pub fn probe_lua() {
+    #[cfg(feature = "lua55")]
+    let artifacts = lua_src::Build::new().build(lua_src::Lua55);
+
    #[cfg(feature = "lua54")]
    let artifacts = lua_src::Build::new().build(lua_src::Lua54);

@@ -1,19 +1,21 @@
 cfg_if::cfg_if! {
-    if #[cfg(all(feature = "lua54", not(any(feature = "lua53", feature = "lua52", feature = "lua51", feature = "luajit", feature = "luau"))))] {
+    if #[cfg(all(feature = "lua55", not(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "lua51", feature = "luajit", feature = "luau"))))] {
        include!("main_inner.rs");
-    } else if #[cfg(all(feature = "lua53", not(any(feature = "lua54", feature = "lua52", feature = "lua51", feature = "luajit", feature = "luau"))))] {
+    } else if #[cfg(all(feature = "lua54", not(any(feature = "lua55", feature = "lua53", feature = "lua52", feature = "lua51", feature = "luajit", feature = "luau"))))] {
        include!("main_inner.rs");
-    } else if #[cfg(all(feature = "lua52", not(any(feature = "lua54", feature = "lua53", feature = "lua51", feature = "luajit", feature = "luau"))))] {
+    } else if #[cfg(all(feature = "lua53", not(any(feature = "lua55", feature = "lua54", feature = "lua52", feature = "lua51", feature = "luajit", feature = "luau"))))] {
        include!("main_inner.rs");
-    } else if #[cfg(all(feature = "lua51", not(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luajit", feature = "luau"))))] {
+    } else if #[cfg(all(feature = "lua52", not(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua51", feature = "luajit", feature = "luau"))))] {
        include!("main_inner.rs");
-    } else if #[cfg(all(feature = "luajit", not(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "lua51", feature = "luau"))))] {
+    } else if #[cfg(all(feature = "lua51", not(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52", feature = "luajit", feature = "luau"))))] {
        include!("main_inner.rs");
-    } else if #[cfg(all(feature = "luau", not(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "lua51", feature = "luajit"))))] {
+    } else if #[cfg(all(feature = "luajit", not(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52", feature = "lua51", feature = "luau"))))] {
+        include!("main_inner.rs");
+    } else if #[cfg(all(feature = "luau", not(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52", feature = "lua51", feature = "luajit"))))] {
        include!("main_inner.rs");
    } else {
        fn main() {
-            compile_error!("You can enable only one of the features: lua54, lua53, lua52, lua51, luajit, luajit52, luau");
+            compile_error!("You can enable only one of the features: lua55, lua54, lua53, lua52, lua51, luajit, luajit52, luau");
        }
    }
 }
@@ -1,4 +1,4 @@
-//! Low level bindings to Lua 5.4/5.3/5.2/5.1 (including LuaJIT) and Luau.
+//! Low level bindings to Lua 5.5/5.4/5.3/5.2/5.1 (including LuaJIT) and Luau.

 #![allow(non_camel_case_types, non_snake_case)]
 #![allow(clippy::missing_safety_doc)]
@@ -8,6 +8,9 @@

 use std::os::raw::c_int;

+#[cfg(any(feature = "lua55", doc))]
+pub use lua55::*;
+
 #[cfg(any(feature = "lua54", doc))]
 pub use lua54::*;

@@ -23,7 +26,7 @@ pub use lua51::*;
 #[cfg(any(feature = "luau", doc))]
 pub use luau::*;

-#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+#[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
 #[doc(hidden)]
 pub const LUA_MAX_UPVALUES: c_int = 255;

@@ -40,14 +43,22 @@ pub const LUA_MAX_UPVALUES: c_int = 200;
 #[doc(hidden)]
 pub const LUA_TRACEBACK_STACK: c_int = 11;

-// Copied from https://github.com/rust-lang/rust/blob/master/library/std/src/sys/pal/common/alloc.rs
-// The minimum alignment guaranteed by the architecture. This value is used to
-// add fast paths for low alignment values.
-#[cfg(any(
+// The minimum alignment guaranteed by the architecture.
+// Copied from https://github.com/rust-lang/rust/blob/main/library/std/src/sys/alloc/mod.rs
+#[doc(hidden)]
+#[rustfmt::skip]
+pub const SYS_MIN_ALIGN: usize = if cfg!(any(
+    all(target_arch = "riscv32", any(target_os = "espidf", target_os = "zkvm")),
+    all(target_arch = "xtensa", target_os = "espidf"),
+)) {
+    // The allocator on the esp-idf and zkvm platforms guarantees 4 byte alignment.
+    4
+} else if cfg!(any(
    target_arch = "x86",
    target_arch = "arm",
    target_arch = "m68k",
    target_arch = "csky",
+    target_arch = "loongarch32",
    target_arch = "mips",
    target_arch = "mips32r6",
    target_arch = "powerpc",
@@ -55,12 +66,11 @@ pub const LUA_TRACEBACK_STACK: c_int = 11;
    target_arch = "sparc",
    target_arch = "wasm32",
    target_arch = "hexagon",
-    all(target_arch = "riscv32", not(any(target_os = "espidf", target_os = "zkvm"))),
-    all(target_arch = "xtensa", not(target_os = "espidf")),
-))]
-#[doc(hidden)]
-pub const SYS_MIN_ALIGN: usize = 8;
-#[cfg(any(
+    target_arch = "riscv32",
+    target_arch = "xtensa",
+)) {
+    8
+} else if cfg!(any(
    target_arch = "x86_64",
    target_arch = "aarch64",
    target_arch = "arm64ec",
@@ -71,20 +81,19 @@ pub const SYS_MIN_ALIGN: usize = 8;
    target_arch = "sparc64",
    target_arch = "riscv64",
    target_arch = "wasm64",
-))]
-#[doc(hidden)]
-pub const SYS_MIN_ALIGN: usize = 16;
-// The allocator on the esp-idf and zkvm platforms guarantee 4 byte alignment.
-#[cfg(any(
-    all(target_arch = "riscv32", any(target_os = "espidf", target_os = "zkvm")),
-    all(target_arch = "xtensa", target_os = "espidf"),
-))]
-#[doc(hidden)]
-pub const SYS_MIN_ALIGN: usize = 4;
+)) {
+    16
+} else {
+    panic!("no value for SYS_MIN_ALIGN")
+};

 #[macro_use]
 mod macros;

+#[cfg(any(feature = "lua55", doc))]
+#[cfg_attr(docsrs, doc(cfg(feature = "lua55")))]
+pub mod lua55;
+
 #[cfg(any(feature = "lua54", doc))]
 #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
 pub mod lua54;
@@ -55,11 +55,7 @@ unsafe fn compat53_checkmode(
        while *st != 0 && *st != c {
            st = st.offset(1);
        }
-        if *st == c {
-            st
-        } else {
-            ptr::null()
-        }
+        if *st == c { st } else { ptr::null() }
    }

    if !mode.is_null() && strchr(mode, *modename).is_null() {
@@ -107,8 +107,6 @@ pub unsafe fn luaL_optstring(L: *mut lua_State, n: c_int, d: *const c_char) -> *
    luaL_optlstring(L, n, d, ptr::null_mut())
 }

-// Deprecated from 5.3: luaL_checkint, luaL_optint, luaL_checklong, luaL_optlong
-
 #[inline(always)]
 pub unsafe fn luaL_typename(L: *mut lua_State, i: c_int) -> *const c_char {
    lua::lua_typename(L, lua::lua_type(L, i))
@@ -138,8 +136,62 @@ pub unsafe fn luaL_getmetatable(L: *mut lua_State, n: *const c_char) {
    lua::lua_getfield_(L, lua::LUA_REGISTRYINDEX, n);
 }

-// TODO: luaL_opt
+#[inline(always)]
+pub unsafe fn luaL_opt<T>(
+    L: *mut lua_State,
+    f: unsafe extern "C-unwind" fn(*mut lua_State, c_int) -> T,
+    n: c_int,
+    d: T,
+) -> T {
+    if lua::lua_isnoneornil(L, n) != 0 {
+        d
+    } else {
+        f(L, n)
+    }
+}

 //
-// TODO: Generic Buffer Manipulation
+// Generic Buffer Manipulation
 //
+
+#[cfg(target_arch = "wasm32")]
+const BUFSIZ: usize = 1024; // WASI libc's BUFSIZ is 1024
+#[cfg(not(target_arch = "wasm32"))]
+const BUFSIZ: usize = libc::BUFSIZ as usize;
+
+// The buffer size used by the lauxlib buffer system.
+// The "16384" workaround is taken from the LuaJIT source code.
+pub const LUAL_BUFFERSIZE: usize = if BUFSIZ > 16384 { 8192 } else { BUFSIZ };
+
+#[repr(C)]
+pub struct luaL_Buffer {
+    pub p: *mut c_char, // current position in buffer
+    pub lvl: c_int,     // number of strings in the stack
+    pub L: *mut lua_State,
+    pub buffer: [c_char; LUAL_BUFFERSIZE],
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua51", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_buffinit(L: *mut lua_State, B: *mut luaL_Buffer);
+    pub fn luaL_prepbuffer(B: *mut luaL_Buffer) -> *mut c_char;
+    pub fn luaL_addlstring(B: *mut luaL_Buffer, s: *const c_char, l: usize);
+    pub fn luaL_addstring(B: *mut luaL_Buffer, s: *const c_char);
+    pub fn luaL_addvalue(B: *mut luaL_Buffer);
+    pub fn luaL_pushresult(B: *mut luaL_Buffer);
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addchar(B: *mut luaL_Buffer, c: c_char) {
+    let buffer_end = (*B).buffer.as_mut_ptr().add(LUAL_BUFFERSIZE);
+    if (*B).p >= buffer_end {
+        luaL_prepbuffer(B);
+    }
+    *(*B).p = c;
+    (*B).p = (*B).p.add(1);
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addsize(B: *mut luaL_Buffer, n: usize) {
+    (*B).p = (*B).p.add(n);
+}
@@ -270,7 +270,10 @@ pub unsafe fn lua_pushcfunction(L: *mut lua_State, f: lua_CFunction) {
    lua_pushcclosure(L, f, 0)
 }

-// TODO: lua_strlen
+#[inline(always)]
+pub unsafe fn lua_strlen(L: *mut lua_State, i: c_int) -> usize {
+    lua_objlen(L, i)
+}

 #[inline(always)]
 pub unsafe fn lua_isfunction(L: *mut lua_State, n: c_int) -> c_int {
@@ -125,7 +125,7 @@ pub unsafe fn lua_rawget(L: *mut lua_State, idx: c_int) -> c_int {

 #[inline(always)]
 pub unsafe fn lua_rawgeti(L: *mut lua_State, idx: c_int, n: lua_Integer) -> c_int {
-    let n = n.try_into().expect("cannot convert index to lua_Integer");
+    let n = n.try_into().expect("cannot convert index to c_int");
    lua_rawgeti_(L, idx, n);
    lua_type(L, -1)
 }
@@ -153,7 +153,7 @@ pub unsafe fn lua_seti(L: *mut lua_State, mut idx: c_int, n: lua_Integer) {

 #[inline(always)]
 pub unsafe fn lua_rawseti(L: *mut lua_State, idx: c_int, n: lua_Integer) {
-    let n = n.try_into().expect("cannot convert index from lua_Integer");
+    let n = n.try_into().expect("cannot convert index to c_int");
    lua_rawseti_(L, idx, n)
 }

@@ -32,7 +32,7 @@ unsafe extern "C-unwind" {
    pub fn luaL_argerror(L: *mut lua_State, arg: c_int, extramsg: *const c_char) -> c_int;
    pub fn luaL_checklstring(L: *mut lua_State, arg: c_int, l: *mut usize) -> *const c_char;
    pub fn luaL_optlstring(L: *mut lua_State, arg: c_int, def: *const c_char, l: *mut usize)
-        -> *const c_char;
+    -> *const c_char;
    pub fn luaL_checknumber(L: *mut lua_State, arg: c_int) -> lua_Number;
    pub fn luaL_optnumber(L: *mut lua_State, arg: c_int, def: lua_Number) -> lua_Number;
    pub fn luaL_checkinteger(L: *mut lua_State, arg: c_int) -> lua_Integer;
@@ -166,13 +166,76 @@ pub unsafe fn luaL_getmetatable(L: *mut lua_State, n: *const c_char) {
    lua::lua_getfield_(L, lua::LUA_REGISTRYINDEX, n);
 }

-// luaL_opt would be implemented here but it is undocumented, so it's omitted
-
 #[inline(always)]
 pub unsafe fn luaL_loadbuffer(L: *mut lua_State, s: *const c_char, sz: usize, n: *const c_char) -> c_int {
    luaL_loadbufferx(L, s, sz, n, ptr::null())
 }

+#[inline(always)]
+pub unsafe fn luaL_opt<T>(
+    L: *mut lua_State,
+    f: unsafe extern "C-unwind" fn(*mut lua_State, c_int) -> T,
+    n: c_int,
+    d: T,
+) -> T {
+    if lua::lua_isnoneornil(L, n) != 0 {
+        d
+    } else {
+        f(L, n)
+    }
+}
+
 //
-// TODO: Generic Buffer Manipulation
+// Generic Buffer Manipulation
 //
+
+#[cfg(target_arch = "wasm32")]
+const BUFSIZ: usize = 1024; // WASI libc's BUFSIZ is 1024
+#[cfg(not(target_arch = "wasm32"))]
+const BUFSIZ: usize = libc::BUFSIZ as usize;
+
+// The buffer size used by the lauxlib buffer system.
+// The "16384" workaround is taken from the LuaJIT source code.
+pub const LUAL_BUFFERSIZE: usize = if BUFSIZ > 16384 { 8192 } else { BUFSIZ };
+
+#[repr(C)]
+pub struct luaL_Buffer {
+    pub b: *mut c_char, // buffer address
+    pub size: usize,    // buffer size
+    pub n: usize,       // number of characters in buffer
+    pub L: *mut lua_State,
+    pub initb: [c_char; LUAL_BUFFERSIZE], // initial buffer space
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua52", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_buffinit(L: *mut lua_State, B: *mut luaL_Buffer);
+    pub fn luaL_prepbuffsize(B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+    pub fn luaL_addlstring(B: *mut luaL_Buffer, s: *const c_char, l: usize);
+    pub fn luaL_addstring(B: *mut luaL_Buffer, s: *const c_char);
+    pub fn luaL_addvalue(B: *mut luaL_Buffer);
+    pub fn luaL_pushresult(B: *mut luaL_Buffer);
+    pub fn luaL_pushresultsize(B: *mut luaL_Buffer, sz: usize);
+    pub fn luaL_buffinitsize(L: *mut lua_State, B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+}
+
+// Macro implementations as inline functions
+
+#[inline(always)]
+pub unsafe fn luaL_prepbuffer(B: *mut luaL_Buffer) -> *mut c_char {
+    luaL_prepbuffsize(B, LUAL_BUFFERSIZE)
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addchar(B: *mut luaL_Buffer, c: c_char) {
+    if (*B).n >= (*B).size {
+        luaL_prepbuffsize(B, 1);
+    }
+    *(*B).b.add((*B).n) = c;
+    (*B).n += 1;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addsize(B: *mut luaL_Buffer, n: usize) {
+    (*B).n += n;
+}
@@ -1,7 +1,7 @@
 //! Contains definitions from `lauxlib.h`.

 use std::os::raw::{c_char, c_int, c_void};
-use std::ptr;
+use std::{mem, ptr};

 use super::lua::{self, lua_CFunction, lua_Integer, lua_Number, lua_State};

@@ -31,7 +31,7 @@ unsafe extern "C-unwind" {
    pub fn luaL_argerror(L: *mut lua_State, arg: c_int, extramsg: *const c_char) -> c_int;
    pub fn luaL_checklstring(L: *mut lua_State, arg: c_int, l: *mut usize) -> *const c_char;
    pub fn luaL_optlstring(L: *mut lua_State, arg: c_int, def: *const c_char, l: *mut usize)
-        -> *const c_char;
+    -> *const c_char;
    pub fn luaL_checknumber(L: *mut lua_State, arg: c_int) -> lua_Number;
    pub fn luaL_optnumber(L: *mut lua_State, arg: c_int, def: lua_Number) -> lua_Number;
    pub fn luaL_checkinteger(L: *mut lua_State, arg: c_int) -> lua_Integer;
@@ -166,13 +166,72 @@ pub unsafe fn luaL_tolstring(L: *mut lua_State, idx: c_int, len: *mut usize) ->
    luaL_tolstring_(L, lua::lua_absindex(L, idx), len)
 }

-// luaL_opt would be implemented here but it is undocumented, so it's omitted
-
 #[inline(always)]
 pub unsafe fn luaL_loadbuffer(L: *mut lua_State, s: *const c_char, sz: usize, n: *const c_char) -> c_int {
    luaL_loadbufferx(L, s, sz, n, ptr::null())
 }

+#[inline(always)]
+pub unsafe fn luaL_opt<T>(
+    L: *mut lua_State,
+    f: unsafe extern "C-unwind" fn(*mut lua_State, c_int) -> T,
+    n: c_int,
+    d: T,
+) -> T {
+    if lua::lua_isnoneornil(L, n) != 0 {
+        d
+    } else {
+        f(L, n)
+    }
+}
+
 //
-// TODO: Generic Buffer Manipulation
+// Generic Buffer Manipulation
 //
+
+// The buffer size used by the lauxlib buffer system.
+// In Lua 5.3: LUAL_BUFFERSIZE = (int)(0x80 * sizeof(void*) * sizeof(lua_Integer))
+#[rustfmt::skip]
+pub const LUAL_BUFFERSIZE: usize = 0x80 * mem::size_of::<*const ()>() * mem::size_of::<lua_Integer>();
+
+#[repr(C)]
+pub struct luaL_Buffer {
+    pub b: *mut c_char, // buffer address
+    pub size: usize,    // buffer size
+    pub n: usize,       // number of characters in buffer
+    pub L: *mut lua_State,
+    pub initb: [c_char; LUAL_BUFFERSIZE], // initial buffer space
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua53", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_buffinit(L: *mut lua_State, B: *mut luaL_Buffer);
+    pub fn luaL_prepbuffsize(B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+    pub fn luaL_addlstring(B: *mut luaL_Buffer, s: *const c_char, l: usize);
+    pub fn luaL_addstring(B: *mut luaL_Buffer, s: *const c_char);
+    pub fn luaL_addvalue(B: *mut luaL_Buffer);
+    pub fn luaL_pushresult(B: *mut luaL_Buffer);
+    pub fn luaL_pushresultsize(B: *mut luaL_Buffer, sz: usize);
+    pub fn luaL_buffinitsize(L: *mut lua_State, B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+}
+
+// Macro implementations as inline functions
+
+#[inline(always)]
+pub unsafe fn luaL_prepbuffer(B: *mut luaL_Buffer) -> *mut c_char {
+    luaL_prepbuffsize(B, LUAL_BUFFERSIZE)
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addchar(B: *mut luaL_Buffer, c: c_char) {
+    if (*B).n >= (*B).size {
+        luaL_prepbuffsize(B, 1);
+    }
+    *(*B).b.add((*B).n) = c;
+    (*B).n += 1;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addsize(B: *mut luaL_Buffer, n: usize) {
+    (*B).n += n;
+}
@@ -1,7 +1,7 @@
 //! Contains definitions from `lauxlib.h`.

-use std::os::raw::{c_char, c_int, c_void};
-use std::ptr;
+use std::os::raw::{c_char, c_double, c_int, c_long, c_void};
+use std::{mem, ptr};

 use super::lua::{self, lua_CFunction, lua_Integer, lua_Number, lua_State};

@@ -30,7 +30,7 @@ unsafe extern "C-unwind" {
    pub fn luaL_argerror(L: *mut lua_State, arg: c_int, extramsg: *const c_char) -> c_int;
    pub fn luaL_checklstring(L: *mut lua_State, arg: c_int, l: *mut usize) -> *const c_char;
    pub fn luaL_optlstring(L: *mut lua_State, arg: c_int, def: *const c_char, l: *mut usize)
-        -> *const c_char;
+    -> *const c_char;
    pub fn luaL_checknumber(L: *mut lua_State, arg: c_int) -> lua_Number;
    pub fn luaL_optnumber(L: *mut lua_State, arg: c_int, def: lua_Number) -> lua_Number;
    pub fn luaL_checkinteger(L: *mut lua_State, arg: c_int) -> lua_Integer;
@@ -91,7 +91,7 @@ unsafe extern "C-unwind" {

    pub fn luaL_len(L: *mut lua_State, idx: c_int) -> lua_Integer;

-    // TODO: luaL_addgsub
+    pub fn luaL_addgsub(B: *mut luaL_Buffer, s: *const c_char, p: *const c_char, r: *const c_char);

    pub fn luaL_gsub(
        L: *mut lua_State,
@@ -162,8 +162,6 @@ pub unsafe fn luaL_getmetatable(L: *mut lua_State, n: *const c_char) {
    lua::lua_getfield(L, lua::LUA_REGISTRYINDEX, n);
 }

-// luaL_opt would be implemented here but it is undocumented, so it's omitted
-
 #[inline(always)]
 pub unsafe fn luaL_loadbuffer(L: *mut lua_State, s: *const c_char, sz: usize, n: *const c_char) -> c_int {
    luaL_loadbufferx(L, s, sz, n, ptr::null())
@@ -188,6 +186,96 @@ pub unsafe fn luaL_loadbufferenv(
    status
 }

+#[inline(always)]
+pub unsafe fn luaL_opt<T>(
+    L: *mut lua_State,
+    f: unsafe extern "C-unwind" fn(*mut lua_State, c_int) -> T,
+    n: c_int,
+    d: T,
+) -> T {
+    if lua::lua_isnoneornil(L, n) != 0 {
+        d
+    } else {
+        f(L, n)
+    }
+}
+
 //
-// TODO: Generic Buffer Manipulation
+// Generic Buffer Manipulation
 //
+
+// The buffer size used by the lauxlib buffer system.
+// LUAL_BUFFERSIZE = (int)(16 * sizeof(void*) * sizeof(lua_Number))
+#[rustfmt::skip]
+pub const LUAL_BUFFERSIZE: usize = 16 * mem::size_of::<*const ()>() * mem::size_of::<lua_Number>();
+
+// Union used for the initial buffer with maximum alignment.
+// This ensures proper alignment for the buffer data.
+#[repr(C)]
+pub union luaL_BufferInit {
+    // Alignment matches LUAI_MAXALIGN
+    pub _align_n: lua_Number,
+    pub _align_u: c_double,
+    pub _align_s: *mut c_void,
+    pub _align_i: lua_Integer,
+    pub _align_l: c_long,
+    // Initial buffer space
+    pub b: [c_char; LUAL_BUFFERSIZE],
+}
+
+#[repr(C)]
+pub struct luaL_Buffer {
+    pub b: *mut c_char, // buffer address
+    pub size: usize,    // buffer size
+    pub n: usize,       // number of characters in buffer
+    pub L: *mut lua_State,
+    pub init: luaL_BufferInit, // initial buffer (union with alignment)
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua54", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_buffinit(L: *mut lua_State, B: *mut luaL_Buffer);
+    pub fn luaL_prepbuffsize(B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+    pub fn luaL_addlstring(B: *mut luaL_Buffer, s: *const c_char, l: usize);
+    pub fn luaL_addstring(B: *mut luaL_Buffer, s: *const c_char);
+    pub fn luaL_addvalue(B: *mut luaL_Buffer);
+    pub fn luaL_pushresult(B: *mut luaL_Buffer);
+    pub fn luaL_pushresultsize(B: *mut luaL_Buffer, sz: usize);
+    pub fn luaL_buffinitsize(L: *mut lua_State, B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+}
+
+// Macro implementations as inline functions
+
+#[inline(always)]
+pub unsafe fn luaL_prepbuffer(B: *mut luaL_Buffer) -> *mut c_char {
+    luaL_prepbuffsize(B, LUAL_BUFFERSIZE)
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addchar(B: *mut luaL_Buffer, c: c_char) {
+    if (*B).n >= (*B).size {
+        luaL_prepbuffsize(B, 1);
+    }
+    *(*B).b.add((*B).n) = c;
+    (*B).n += 1;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addsize(B: *mut luaL_Buffer, n: usize) {
+    (*B).n += n;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_buffsub(B: *mut luaL_Buffer, n: usize) {
+    (*B).n -= n;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_bufflen(B: *mut luaL_Buffer) -> usize {
+    (*B).n
+}
+
+#[inline(always)]
+pub unsafe fn luaL_buffaddr(B: *mut luaL_Buffer) -> *mut c_char {
+    (*B).b
+}
@@ -0,0 +1,299 @@
+//! Contains definitions from `lauxlib.h`.
+
+use std::os::raw::{c_char, c_double, c_int, c_long, c_uint, c_void};
+use std::{mem, ptr};
+
+use super::lua::{self, lua_CFunction, lua_Integer, lua_Number, lua_State};
+
+// Extra error code for 'luaL_loadfilex'
+pub const LUA_ERRFILE: c_int = lua::LUA_ERRERR + 1;
+
+// Key, in the registry, for table of loaded modules
+pub const LUA_LOADED_TABLE: *const c_char = cstr!("_LOADED");
+
+// Key, in the registry, for table of preloaded loaders
+pub const LUA_PRELOAD_TABLE: *const c_char = cstr!("_PRELOAD");
+
+#[repr(C)]
+pub struct luaL_Reg {
+    pub name: *const c_char,
+    pub func: lua_CFunction,
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_checkversion_(L: *mut lua_State, ver: lua_Number, sz: usize);
+
+    pub fn luaL_getmetafield(L: *mut lua_State, obj: c_int, e: *const c_char) -> c_int;
+    pub fn luaL_callmeta(L: *mut lua_State, obj: c_int, e: *const c_char) -> c_int;
+    pub fn luaL_tolstring(L: *mut lua_State, idx: c_int, len: *mut usize) -> *const c_char;
+    pub fn luaL_argerror(L: *mut lua_State, arg: c_int, extramsg: *const c_char) -> c_int;
+    pub fn luaL_checklstring(L: *mut lua_State, arg: c_int, l: *mut usize) -> *const c_char;
+    pub fn luaL_optlstring(L: *mut lua_State, arg: c_int, def: *const c_char, l: *mut usize)
+    -> *const c_char;
+    pub fn luaL_checknumber(L: *mut lua_State, arg: c_int) -> lua_Number;
+    pub fn luaL_optnumber(L: *mut lua_State, arg: c_int, def: lua_Number) -> lua_Number;
+    pub fn luaL_checkinteger(L: *mut lua_State, arg: c_int) -> lua_Integer;
+    pub fn luaL_optinteger(L: *mut lua_State, arg: c_int, def: lua_Integer) -> lua_Integer;
+
+    pub fn luaL_checkstack(L: *mut lua_State, sz: c_int, msg: *const c_char);
+    pub fn luaL_checktype(L: *mut lua_State, arg: c_int, t: c_int);
+    pub fn luaL_checkany(L: *mut lua_State, arg: c_int);
+
+    pub fn luaL_newmetatable(L: *mut lua_State, tname: *const c_char) -> c_int;
+    pub fn luaL_setmetatable(L: *mut lua_State, tname: *const c_char);
+    pub fn luaL_testudata(L: *mut lua_State, ud: c_int, tname: *const c_char) -> *mut c_void;
+    pub fn luaL_checkudata(L: *mut lua_State, ud: c_int, tname: *const c_char) -> *mut c_void;
+
+    pub fn luaL_where(L: *mut lua_State, lvl: c_int);
+    pub fn luaL_error(L: *mut lua_State, fmt: *const c_char, ...) -> c_int;
+
+    pub fn luaL_checkoption(
+        L: *mut lua_State,
+        arg: c_int,
+        def: *const c_char,
+        lst: *const *const c_char,
+    ) -> c_int;
+
+    pub fn luaL_fileresult(L: *mut lua_State, stat: c_int, fname: *const c_char) -> c_int;
+    pub fn luaL_execresult(L: *mut lua_State, stat: c_int) -> c_int;
+    pub fn luaL_alloc(L: *mut lua_State, ptr: *mut c_void, osize: usize, nsize: usize) -> *mut c_void;
+}
+
+// Pre-defined references
+pub const LUA_NOREF: c_int = -2;
+pub const LUA_REFNIL: c_int = -1;
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_ref(L: *mut lua_State, t: c_int) -> c_int;
+    pub fn luaL_unref(L: *mut lua_State, t: c_int, r#ref: c_int);
+
+    pub fn luaL_loadfilex(L: *mut lua_State, filename: *const c_char, mode: *const c_char) -> c_int;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_loadfile(L: *mut lua_State, f: *const c_char) -> c_int {
+    luaL_loadfilex(L, f, ptr::null())
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_loadbufferx(
+        L: *mut lua_State,
+        buff: *const c_char,
+        sz: usize,
+        name: *const c_char,
+        mode: *const c_char,
+    ) -> c_int;
+    pub fn luaL_loadstring(L: *mut lua_State, s: *const c_char) -> c_int;
+
+    pub fn luaL_newstate() -> *mut lua_State;
+
+    #[link_name = "luaL_makeseed"]
+    pub fn luaL_makeseed_(L: *mut lua_State) -> c_uint;
+
+    pub fn luaL_len(L: *mut lua_State, idx: c_int) -> lua_Integer;
+
+    pub fn luaL_addgsub(B: *mut luaL_Buffer, s: *const c_char, p: *const c_char, r: *const c_char);
+
+    pub fn luaL_gsub(
+        L: *mut lua_State,
+        s: *const c_char,
+        p: *const c_char,
+        r: *const c_char,
+    ) -> *const c_char;
+
+    pub fn luaL_setfuncs(L: *mut lua_State, l: *const luaL_Reg, nup: c_int);
+
+    pub fn luaL_getsubtable(L: *mut lua_State, idx: c_int, fname: *const c_char) -> c_int;
+
+    pub fn luaL_traceback(L: *mut lua_State, L1: *mut lua_State, msg: *const c_char, level: c_int);
+
+    pub fn luaL_requiref(L: *mut lua_State, modname: *const c_char, openf: lua_CFunction, glb: c_int);
+}
+
+//
+// Some useful macros (implemented as Rust functions)
+//
+
+// TODO: luaL_newlibtable, luaL_newlib
+
+#[inline(always)]
+pub unsafe fn luaL_argcheck(L: *mut lua_State, cond: c_int, arg: c_int, extramsg: *const c_char) {
+    if cond == 0 {
+        luaL_argerror(L, arg, extramsg);
+    }
+}
+
+#[inline(always)]
+pub unsafe fn luaL_checkstring(L: *mut lua_State, n: c_int) -> *const c_char {
+    luaL_checklstring(L, n, ptr::null_mut())
+}
+
+#[inline(always)]
+pub unsafe fn luaL_optstring(L: *mut lua_State, n: c_int, d: *const c_char) -> *const c_char {
+    luaL_optlstring(L, n, d, ptr::null_mut())
+}
+
+#[inline(always)]
+pub unsafe fn luaL_typename(L: *mut lua_State, i: c_int) -> *const c_char {
+    lua::lua_typename(L, lua::lua_type(L, i))
+}
+
+#[inline(always)]
+pub unsafe fn luaL_dofile(L: *mut lua_State, filename: *const c_char) -> c_int {
+    let status = luaL_loadfile(L, filename);
+    if status == 0 {
+        lua::lua_pcall(L, 0, lua::LUA_MULTRET, 0)
+    } else {
+        status
+    }
+}
+
+#[inline(always)]
+pub unsafe fn luaL_dostring(L: *mut lua_State, s: *const c_char) -> c_int {
+    let status = luaL_loadstring(L, s);
+    if status == 0 {
+        lua::lua_pcall(L, 0, lua::LUA_MULTRET, 0)
+    } else {
+        status
+    }
+}
+
+#[inline(always)]
+pub unsafe fn luaL_getmetatable(L: *mut lua_State, n: *const c_char) {
+    lua::lua_getfield(L, lua::LUA_REGISTRYINDEX, n);
+}
+
+#[inline(always)]
+pub unsafe fn luaL_loadbuffer(L: *mut lua_State, s: *const c_char, sz: usize, n: *const c_char) -> c_int {
+    luaL_loadbufferx(L, s, sz, n, ptr::null())
+}
+
+pub unsafe fn luaL_loadbufferenv(
+    L: *mut lua_State,
+    data: *const c_char,
+    size: usize,
+    name: *const c_char,
+    mode: *const c_char,
+    mut env: c_int,
+) -> c_int {
+    if env != 0 {
+        env = lua::lua_absindex(L, env);
+    }
+    let status = luaL_loadbufferx(L, data, size, name, mode);
+    if status == lua::LUA_OK && env != 0 {
+        lua::lua_pushvalue(L, env);
+        lua::lua_setupvalue(L, -2, 1);
+    }
+    status
+}
+
+pub unsafe fn luaL_makeseed(L: *mut lua_State) -> c_uint {
+    #[cfg(macos)]
+    return libc::arc4random();
+    #[cfg(linux)]
+    {
+        let mut seed = 0u32;
+        let buf = &mut seed as *mut _ as *mut c_void;
+        if libc::getrandom(buf, 4, libc::GRND_NONBLOCK) == 4 {
+            return seed;
+        }
+    }
+    luaL_makeseed_(L)
+}
+
+#[inline(always)]
+pub unsafe fn luaL_opt<T>(
+    L: *mut lua_State,
+    f: unsafe extern "C-unwind" fn(*mut lua_State, c_int) -> T,
+    n: c_int,
+    d: T,
+) -> T {
+    if lua::lua_isnoneornil(L, n) != 0 {
+        d
+    } else {
+        f(L, n)
+    }
+}
+
+//
+// Generic Buffer Manipulation
+//
+
+// The buffer size used by the lauxlib buffer system.
+// LUAL_BUFFERSIZE = (int)(16 * sizeof(void*) * sizeof(lua_Number))
+#[rustfmt::skip]
+pub const LUAL_BUFFERSIZE: usize = 16 * mem::size_of::<*const ()>() * mem::size_of::<lua_Number>();
+
+// Union used for the initial buffer with maximum alignment.
+// This ensures proper alignment for the buffer data.
+#[repr(C)]
+pub union luaL_BufferInit {
+    // Alignment matches LUAI_MAXALIGN
+    pub _align_n: lua_Number,
+    pub _align_u: c_double,
+    pub _align_s: *mut c_void,
+    pub _align_i: lua_Integer,
+    pub _align_l: c_long,
+    // Initial buffer space
+    pub b: [c_char; LUAL_BUFFERSIZE],
+}
+
+#[repr(C)]
+pub struct luaL_Buffer {
+    pub b: *mut c_char, // buffer address
+    pub size: usize,    // buffer size
+    pub n: usize,       // number of characters in buffer
+    pub L: *mut lua_State,
+    pub init: luaL_BufferInit, // initial buffer (union with alignment)
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaL_buffinit(L: *mut lua_State, B: *mut luaL_Buffer);
+    pub fn luaL_prepbuffsize(B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+    pub fn luaL_addlstring(B: *mut luaL_Buffer, s: *const c_char, l: usize);
+    pub fn luaL_addstring(B: *mut luaL_Buffer, s: *const c_char);
+    pub fn luaL_addvalue(B: *mut luaL_Buffer);
+    pub fn luaL_pushresult(B: *mut luaL_Buffer);
+    pub fn luaL_pushresultsize(B: *mut luaL_Buffer, sz: usize);
+    pub fn luaL_buffinitsize(L: *mut lua_State, B: *mut luaL_Buffer, sz: usize) -> *mut c_char;
+}
+
+// Macro implementations as inline functions
+
+#[inline(always)]
+pub unsafe fn luaL_prepbuffer(B: *mut luaL_Buffer) -> *mut c_char {
+    luaL_prepbuffsize(B, LUAL_BUFFERSIZE)
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addchar(B: *mut luaL_Buffer, c: c_char) {
+    if (*B).n >= (*B).size {
+        luaL_prepbuffsize(B, 1);
+    }
+    *(*B).b.add((*B).n) = c;
+    (*B).n += 1;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_addsize(B: *mut luaL_Buffer, n: usize) {
+    (*B).n += n;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_buffsub(B: *mut luaL_Buffer, n: usize) {
+    (*B).n -= n;
+}
+
+#[inline(always)]
+pub unsafe fn luaL_bufflen(B: *mut luaL_Buffer) -> usize {
+    (*B).n
+}
+
+#[inline(always)]
+pub unsafe fn luaL_buffaddr(B: *mut luaL_Buffer) -> *mut c_char {
+    (*B).b
+}
@@ -0,0 +1,578 @@
+//! Contains definitions from `lua.h`.
+
+use std::ffi::CStr;
+use std::marker::{PhantomData, PhantomPinned};
+use std::os::raw::{c_char, c_double, c_int, c_uchar, c_uint, c_void};
+use std::{mem, ptr};
+
+// Mark for precompiled code (`<esc>Lua`)
+pub const LUA_SIGNATURE: &[u8] = b"\x1bLua";
+
+// Option for multiple returns in 'lua_pcall' and 'lua_call'
+pub const LUA_MULTRET: c_int = -1;
+
+// Size of the Lua stack
+#[doc(hidden)]
+pub const LUAI_MAXSTACK: c_int = c_int::MAX;
+
+// Size of a raw memory area associated with  a Lua state with very fast access.
+pub const LUA_EXTRASPACE: usize = mem::size_of::<*const ()>();
+
+//
+// Pseudo-indices
+//
+pub const LUA_REGISTRYINDEX: c_int = -(c_int::MAX / 2 + 1000);
+
+pub const fn lua_upvalueindex(i: c_int) -> c_int {
+    LUA_REGISTRYINDEX - i
+}
+
+//
+// Thread status
+//
+pub const LUA_OK: c_int = 0;
+pub const LUA_YIELD: c_int = 1;
+pub const LUA_ERRRUN: c_int = 2;
+pub const LUA_ERRSYNTAX: c_int = 3;
+pub const LUA_ERRMEM: c_int = 4;
+pub const LUA_ERRERR: c_int = 5;
+
+/// A raw Lua state associated with a thread.
+#[repr(C)]
+pub struct lua_State {
+    _data: [u8; 0],
+    _marker: PhantomData<(*mut u8, PhantomPinned)>,
+}
+
+//
+// Basic types
+//
+pub const LUA_TNONE: c_int = -1;
+
+pub const LUA_TNIL: c_int = 0;
+pub const LUA_TBOOLEAN: c_int = 1;
+pub const LUA_TLIGHTUSERDATA: c_int = 2;
+pub const LUA_TNUMBER: c_int = 3;
+pub const LUA_TSTRING: c_int = 4;
+pub const LUA_TTABLE: c_int = 5;
+pub const LUA_TFUNCTION: c_int = 6;
+pub const LUA_TUSERDATA: c_int = 7;
+pub const LUA_TTHREAD: c_int = 8;
+
+pub const LUA_NUMTYPES: c_int = 9;
+
+/// Minimum Lua stack available to a C function
+pub const LUA_MINSTACK: c_int = 20;
+
+// Predefined values in the registry
+// index 1 is reserved for the reference mechanism
+pub const LUA_RIDX_GLOBALS: lua_Integer = 2;
+pub const LUA_RIDX_MAINTHREAD: lua_Integer = 3;
+pub const LUA_RIDX_LAST: lua_Integer = 3;
+
+/// A Lua number, usually equivalent to `f64`
+pub type lua_Number = c_double;
+
+/// A Lua integer, usually equivalent to `i64`
+pub type lua_Integer = i64;
+
+/// A Lua unsigned integer, usually equivalent to `u64`
+pub type lua_Unsigned = u64;
+
+/// Type for continuation-function contexts
+pub type lua_KContext = isize;
+
+/// Type for native C functions that can be passed to Lua
+pub type lua_CFunction = unsafe extern "C-unwind" fn(L: *mut lua_State) -> c_int;
+
+/// Type for continuation functions
+pub type lua_KFunction =
+    unsafe extern "C-unwind" fn(L: *mut lua_State, status: c_int, ctx: lua_KContext) -> c_int;
+
+// Type for functions that read/write blocks when loading/dumping Lua chunks
+#[rustfmt::skip]
+pub type lua_Reader =
+    unsafe extern "C-unwind" fn(L: *mut lua_State, ud: *mut c_void, sz: *mut usize) -> *const c_char;
+#[rustfmt::skip]
+pub type lua_Writer =
+    unsafe extern "C-unwind" fn(L: *mut lua_State, p: *const c_void, sz: usize, ud: *mut c_void) -> c_int;
+
+/// Type for memory-allocation functions (no unwinding)
+#[rustfmt::skip]
+pub type lua_Alloc =
+    unsafe extern "C" fn(ud: *mut c_void, ptr: *mut c_void, osize: usize, nsize: usize) -> *mut c_void;
+
+/// Type for warning functions
+pub type lua_WarnFunction = unsafe extern "C-unwind" fn(ud: *mut c_void, msg: *const c_char, tocont: c_int);
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    //
+    // State manipulation
+    //
+    pub fn lua_newstate(f: lua_Alloc, ud: *mut c_void, seed: c_uint) -> *mut lua_State;
+    pub fn lua_close(L: *mut lua_State);
+    pub fn lua_newthread(L: *mut lua_State) -> *mut lua_State;
+    pub fn lua_closethread(L: *mut lua_State, from: *mut lua_State) -> c_int;
+
+    pub fn lua_atpanic(L: *mut lua_State, panicf: lua_CFunction) -> lua_CFunction;
+
+    pub fn lua_version(L: *mut lua_State) -> lua_Number;
+
+    //
+    // Basic stack manipulation
+    //
+    pub fn lua_absindex(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_gettop(L: *mut lua_State) -> c_int;
+    pub fn lua_settop(L: *mut lua_State, idx: c_int);
+    pub fn lua_pushvalue(L: *mut lua_State, idx: c_int);
+    pub fn lua_rotate(L: *mut lua_State, idx: c_int, n: c_int);
+    pub fn lua_copy(L: *mut lua_State, fromidx: c_int, toidx: c_int);
+    pub fn lua_checkstack(L: *mut lua_State, sz: c_int) -> c_int;
+
+    pub fn lua_xmove(from: *mut lua_State, to: *mut lua_State, n: c_int);
+
+    //
+    // Access functions (stack -> C)
+    //
+    pub fn lua_isnumber(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_isstring(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_iscfunction(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_isinteger(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_isuserdata(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_type(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_typename(L: *mut lua_State, tp: c_int) -> *const c_char;
+
+    pub fn lua_tonumberx(L: *mut lua_State, idx: c_int, isnum: *mut c_int) -> lua_Number;
+    pub fn lua_tointegerx(L: *mut lua_State, idx: c_int, isnum: *mut c_int) -> lua_Integer;
+    pub fn lua_toboolean(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_tolstring(L: *mut lua_State, idx: c_int, len: *mut usize) -> *const c_char;
+    #[link_name = "lua_rawlen"]
+    fn lua_rawlen_(L: *mut lua_State, idx: c_int) -> lua_Unsigned;
+    pub fn lua_tocfunction(L: *mut lua_State, idx: c_int) -> Option<lua_CFunction>;
+    pub fn lua_touserdata(L: *mut lua_State, idx: c_int) -> *mut c_void;
+    pub fn lua_tothread(L: *mut lua_State, idx: c_int) -> *mut lua_State;
+    pub fn lua_topointer(L: *mut lua_State, idx: c_int) -> *const c_void;
+}
+
+// lua_rawlen's return type changed from size_t to lua_Unsigned int in Lua 5.4.
+// This adapts the crate API to the new Lua ABI.
+#[inline(always)]
+pub unsafe fn lua_rawlen(L: *mut lua_State, idx: c_int) -> usize {
+    lua_rawlen_(L, idx) as usize
+}
+
+//
+// Comparison and arithmetic functions
+//
+pub const LUA_OPADD: c_int = 0;
+pub const LUA_OPSUB: c_int = 1;
+pub const LUA_OPMUL: c_int = 2;
+pub const LUA_OPMOD: c_int = 3;
+pub const LUA_OPPOW: c_int = 4;
+pub const LUA_OPDIV: c_int = 5;
+pub const LUA_OPIDIV: c_int = 6;
+pub const LUA_OPBAND: c_int = 7;
+pub const LUA_OPBOR: c_int = 8;
+pub const LUA_OPBXOR: c_int = 9;
+pub const LUA_OPSHL: c_int = 10;
+pub const LUA_OPSHR: c_int = 11;
+pub const LUA_OPUNM: c_int = 12;
+pub const LUA_OPBNOT: c_int = 13;
+
+pub const LUA_OPEQ: c_int = 0;
+pub const LUA_OPLT: c_int = 1;
+pub const LUA_OPLE: c_int = 2;
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn lua_arith(L: *mut lua_State, op: c_int);
+    pub fn lua_rawequal(L: *mut lua_State, idx1: c_int, idx2: c_int) -> c_int;
+    pub fn lua_compare(L: *mut lua_State, idx1: c_int, idx2: c_int, op: c_int) -> c_int;
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    //
+    // Push functions (C -> stack)
+    //
+    pub fn lua_pushnil(L: *mut lua_State);
+    pub fn lua_pushnumber(L: *mut lua_State, n: lua_Number);
+    pub fn lua_pushinteger(L: *mut lua_State, n: lua_Integer);
+    pub fn lua_pushlstring(L: *mut lua_State, s: *const c_char, len: usize) -> *const c_char;
+    pub fn lua_pushexternalstring(
+        L: *mut lua_State,
+        s: *const c_char,
+        len: usize,
+        falloc: Option<lua_Alloc>,
+        ud: *mut c_void,
+    ) -> *const c_char;
+    pub fn lua_pushstring(L: *mut lua_State, s: *const c_char) -> *const c_char;
+    // lua_pushvfstring
+    pub fn lua_pushfstring(L: *mut lua_State, fmt: *const c_char, ...) -> *const c_char;
+    pub fn lua_pushcclosure(L: *mut lua_State, f: lua_CFunction, n: c_int);
+    pub fn lua_pushboolean(L: *mut lua_State, b: c_int);
+    pub fn lua_pushlightuserdata(L: *mut lua_State, p: *mut c_void);
+    pub fn lua_pushthread(L: *mut lua_State) -> c_int;
+
+    //
+    // Get functions (Lua -> stack)
+    //
+    pub fn lua_getglobal(L: *mut lua_State, name: *const c_char) -> c_int;
+    pub fn lua_gettable(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_getfield(L: *mut lua_State, idx: c_int, k: *const c_char) -> c_int;
+    pub fn lua_geti(L: *mut lua_State, idx: c_int, n: lua_Integer) -> c_int;
+    pub fn lua_rawget(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_rawgeti(L: *mut lua_State, idx: c_int, n: lua_Integer) -> c_int;
+    pub fn lua_rawgetp(L: *mut lua_State, idx: c_int, p: *const c_void) -> c_int;
+
+    pub fn lua_createtable(L: *mut lua_State, narr: c_int, nrec: c_int);
+    pub fn lua_newuserdatauv(L: *mut lua_State, sz: usize, nuvalue: c_int) -> *mut c_void;
+    pub fn lua_getmetatable(L: *mut lua_State, objindex: c_int) -> c_int;
+    pub fn lua_getiuservalue(L: *mut lua_State, idx: c_int, n: c_int) -> c_int;
+
+    //
+    // Set functions (stack -> Lua)
+    //
+    pub fn lua_setglobal(L: *mut lua_State, name: *const c_char);
+    pub fn lua_settable(L: *mut lua_State, idx: c_int);
+    pub fn lua_setfield(L: *mut lua_State, idx: c_int, k: *const c_char);
+    pub fn lua_seti(L: *mut lua_State, idx: c_int, n: lua_Integer);
+    pub fn lua_rawset(L: *mut lua_State, idx: c_int);
+    pub fn lua_rawseti(L: *mut lua_State, idx: c_int, n: lua_Integer);
+    pub fn lua_rawsetp(L: *mut lua_State, idx: c_int, p: *const c_void);
+    pub fn lua_setmetatable(L: *mut lua_State, objindex: c_int) -> c_int;
+    pub fn lua_setiuservalue(L: *mut lua_State, idx: c_int, n: c_int) -> c_int;
+
+    //
+    // 'load' and 'call' functions (load and run Lua code)
+    //
+    pub fn lua_callk(
+        L: *mut lua_State,
+        nargs: c_int,
+        nresults: c_int,
+        ctx: lua_KContext,
+        k: Option<lua_KFunction>,
+    );
+    pub fn lua_pcallk(
+        L: *mut lua_State,
+        nargs: c_int,
+        nresults: c_int,
+        errfunc: c_int,
+        ctx: lua_KContext,
+        k: Option<lua_KFunction>,
+    ) -> c_int;
+
+    pub fn lua_load(
+        L: *mut lua_State,
+        reader: lua_Reader,
+        data: *mut c_void,
+        chunkname: *const c_char,
+        mode: *const c_char,
+    ) -> c_int;
+
+    pub fn lua_dump(L: *mut lua_State, writer: lua_Writer, data: *mut c_void, strip: c_int) -> c_int;
+}
+
+#[inline(always)]
+pub unsafe fn lua_call(L: *mut lua_State, n: c_int, r: c_int) {
+    lua_callk(L, n, r, 0, None)
+}
+
+#[inline(always)]
+pub unsafe fn lua_pcall(L: *mut lua_State, n: c_int, r: c_int, f: c_int) -> c_int {
+    lua_pcallk(L, n, r, f, 0, None)
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    //
+    // Coroutine functions
+    //
+    pub fn lua_yieldk(
+        L: *mut lua_State,
+        nresults: c_int,
+        ctx: lua_KContext,
+        k: Option<lua_KFunction>,
+    ) -> c_int;
+    pub fn lua_resume(L: *mut lua_State, from: *mut lua_State, narg: c_int, nres: *mut c_int) -> c_int;
+    pub fn lua_status(L: *mut lua_State) -> c_int;
+    pub fn lua_isyieldable(L: *mut lua_State) -> c_int;
+}
+
+#[inline(always)]
+pub unsafe fn lua_yield(L: *mut lua_State, n: c_int) -> c_int {
+    lua_yieldk(L, n, 0, None)
+}
+
+//
+// Warning-related functions
+//
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn lua_setwarnf(L: *mut lua_State, f: Option<lua_WarnFunction>, ud: *mut c_void);
+    pub fn lua_warning(L: *mut lua_State, msg: *const c_char, tocont: c_int);
+}
+
+//
+// Garbage-collection options
+//
+pub const LUA_GCSTOP: c_int = 0;
+pub const LUA_GCRESTART: c_int = 1;
+pub const LUA_GCCOLLECT: c_int = 2;
+pub const LUA_GCCOUNT: c_int = 3;
+pub const LUA_GCCOUNTB: c_int = 4;
+pub const LUA_GCSTEP: c_int = 5;
+pub const LUA_GCISRUNNING: c_int = 6;
+pub const LUA_GCGEN: c_int = 7;
+pub const LUA_GCINC: c_int = 8;
+pub const LUA_GCPARAM: c_int = 9;
+
+// Parameters for GC generational mode
+pub const LUA_GCPMINORMUL: c_int = 0; // control minor collections
+pub const LUA_GCPMAJORMINOR: c_int = 1; // control shift major->minor
+pub const LUA_GCPMINORMAJOR: c_int = 2; // control shift minor->major
+
+// Parameters for GC incremental mode
+pub const LUA_GCPPAUSE: c_int = 3; // size of pause between successive GCs
+pub const LUA_GCPSTEPMUL: c_int = 4; // GC "speed"
+pub const LUA_GCPSTEPSIZE: c_int = 5; // GC granularity
+
+pub const LUA_GCPNUM: c_int = 6; // number of parameters
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn lua_gc(L: *mut lua_State, what: c_int, ...) -> c_int;
+}
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    //
+    // Miscellaneous functions
+    //
+    #[link_name = "lua_error"]
+    fn lua_error_(L: *mut lua_State) -> c_int;
+    pub fn lua_next(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_concat(L: *mut lua_State, n: c_int);
+    pub fn lua_len(L: *mut lua_State, idx: c_int);
+    pub fn lua_numbertocstring(L: *mut lua_State, idx: c_int, buff: *mut c_char) -> c_uint;
+    pub fn lua_stringtonumber(L: *mut lua_State, s: *const c_char) -> usize;
+    pub fn lua_getallocf(L: *mut lua_State, ud: *mut *mut c_void) -> lua_Alloc;
+    pub fn lua_setallocf(L: *mut lua_State, f: lua_Alloc, ud: *mut c_void);
+
+    pub fn lua_toclose(L: *mut lua_State, idx: c_int);
+    pub fn lua_closeslot(L: *mut lua_State, idx: c_int);
+}
+
+// lua_error does not return but is declared to return int, and Rust translates
+// ! to void which can cause link-time errors if the platform linker is aware
+// of return types and requires they match (for example: wasm does this).
+#[inline(always)]
+pub unsafe fn lua_error(L: *mut lua_State) -> ! {
+    lua_error_(L);
+    unreachable!();
+}
+
+//
+// Some useful macros (implemented as Rust functions)
+//
+#[inline(always)]
+pub unsafe fn lua_getextraspace(L: *mut lua_State) -> *mut c_void {
+    (L as *mut c_char).sub(LUA_EXTRASPACE) as *mut c_void
+}
+
+#[inline(always)]
+pub unsafe fn lua_tonumber(L: *mut lua_State, i: c_int) -> lua_Number {
+    lua_tonumberx(L, i, ptr::null_mut())
+}
+
+#[inline(always)]
+pub unsafe fn lua_tointeger(L: *mut lua_State, i: c_int) -> lua_Integer {
+    lua_tointegerx(L, i, ptr::null_mut())
+}
+
+#[inline(always)]
+pub unsafe fn lua_pop(L: *mut lua_State, n: c_int) {
+    lua_settop(L, -n - 1)
+}
+
+#[inline(always)]
+pub unsafe fn lua_newtable(L: *mut lua_State) {
+    lua_createtable(L, 0, 0)
+}
+
+#[inline(always)]
+pub unsafe fn lua_register(L: *mut lua_State, n: *const c_char, f: lua_CFunction) {
+    lua_pushcfunction(L, f);
+    lua_setglobal(L, n)
+}
+
+#[inline(always)]
+pub unsafe fn lua_pushcfunction(L: *mut lua_State, f: lua_CFunction) {
+    lua_pushcclosure(L, f, 0)
+}
+
+#[inline(always)]
+pub unsafe fn lua_isfunction(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TFUNCTION) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_istable(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TTABLE) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_islightuserdata(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TLIGHTUSERDATA) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_isnil(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TNIL) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_isboolean(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TBOOLEAN) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_isthread(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TTHREAD) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_isnone(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TNONE) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_isnoneornil(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) <= 0) as c_int
+}
+
+#[inline(always)]
+pub unsafe fn lua_pushliteral(L: *mut lua_State, s: &'static CStr) {
+    lua_pushstring(L, s.as_ptr());
+}
+
+#[inline(always)]
+pub unsafe fn lua_pushglobaltable(L: *mut lua_State) -> c_int {
+    lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS)
+}
+
+#[inline(always)]
+pub unsafe fn lua_tolightuserdata(L: *mut lua_State, idx: c_int) -> *mut c_void {
+    if lua_islightuserdata(L, idx) != 0 {
+        return lua_touserdata(L, idx);
+    }
+    ptr::null_mut()
+}
+
+#[inline(always)]
+pub unsafe fn lua_tostring(L: *mut lua_State, i: c_int) -> *const c_char {
+    lua_tolstring(L, i, ptr::null_mut())
+}
+
+#[inline(always)]
+pub unsafe fn lua_insert(L: *mut lua_State, idx: c_int) {
+    lua_rotate(L, idx, 1)
+}
+
+#[inline(always)]
+pub unsafe fn lua_remove(L: *mut lua_State, idx: c_int) {
+    lua_rotate(L, idx, -1);
+    lua_pop(L, 1)
+}
+
+#[inline(always)]
+pub unsafe fn lua_replace(L: *mut lua_State, idx: c_int) {
+    lua_copy(L, -1, idx);
+    lua_pop(L, 1)
+}
+
+#[inline(always)]
+pub unsafe fn lua_xpush(from: *mut lua_State, to: *mut lua_State, idx: c_int) {
+    lua_pushvalue(from, idx);
+    lua_xmove(from, to, 1);
+}
+
+#[inline(always)]
+pub unsafe fn lua_newuserdata(L: *mut lua_State, sz: usize) -> *mut c_void {
+    lua_newuserdatauv(L, sz, 1)
+}
+
+#[inline(always)]
+pub unsafe fn lua_getuservalue(L: *mut lua_State, idx: c_int) -> c_int {
+    lua_getiuservalue(L, idx, 1)
+}
+
+#[inline(always)]
+pub unsafe fn lua_setuservalue(L: *mut lua_State, idx: c_int) -> c_int {
+    lua_setiuservalue(L, idx, 1)
+}
+
+//
+// Debug API
+//
+
+// Maximum size for the description of the source of a function in debug information.
+const LUA_IDSIZE: usize = 60;
+
+// Event codes
+pub const LUA_HOOKCALL: c_int = 0;
+pub const LUA_HOOKRET: c_int = 1;
+pub const LUA_HOOKLINE: c_int = 2;
+pub const LUA_HOOKCOUNT: c_int = 3;
+pub const LUA_HOOKTAILCALL: c_int = 4;
+
+// Event masks
+pub const LUA_MASKCALL: c_int = 1 << (LUA_HOOKCALL as usize);
+pub const LUA_MASKRET: c_int = 1 << (LUA_HOOKRET as usize);
+pub const LUA_MASKLINE: c_int = 1 << (LUA_HOOKLINE as usize);
+pub const LUA_MASKCOUNT: c_int = 1 << (LUA_HOOKCOUNT as usize);
+
+/// Type for functions to be called on debug events.
+pub type lua_Hook = unsafe extern "C-unwind" fn(L: *mut lua_State, ar: *mut lua_Debug);
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn lua_getstack(L: *mut lua_State, level: c_int, ar: *mut lua_Debug) -> c_int;
+    pub fn lua_getinfo(L: *mut lua_State, what: *const c_char, ar: *mut lua_Debug) -> c_int;
+    pub fn lua_getlocal(L: *mut lua_State, ar: *const lua_Debug, n: c_int) -> *const c_char;
+    pub fn lua_setlocal(L: *mut lua_State, ar: *const lua_Debug, n: c_int) -> *const c_char;
+    pub fn lua_getupvalue(L: *mut lua_State, funcindex: c_int, n: c_int) -> *const c_char;
+    pub fn lua_setupvalue(L: *mut lua_State, funcindex: c_int, n: c_int) -> *const c_char;
+
+    pub fn lua_upvalueid(L: *mut lua_State, fidx: c_int, n: c_int) -> *mut c_void;
+    pub fn lua_upvaluejoin(L: *mut lua_State, fidx1: c_int, n1: c_int, fidx2: c_int, n2: c_int);
+
+    pub fn lua_sethook(L: *mut lua_State, func: Option<lua_Hook>, mask: c_int, count: c_int);
+    pub fn lua_gethook(L: *mut lua_State) -> Option<lua_Hook>;
+    pub fn lua_gethookmask(L: *mut lua_State) -> c_int;
+    pub fn lua_gethookcount(L: *mut lua_State) -> c_int;
+}
+
+#[repr(C)]
+pub struct lua_Debug {
+    pub event: c_int,
+    pub name: *const c_char,             // (n)
+    pub namewhat: *const c_char,         // (n) 'global', 'local', 'field', 'method'
+    pub what: *const c_char,             // (S) 'Lua', 'C', 'main', 'tail'
+    pub source: *const c_char,           // (S)
+    pub srclen: usize,                   // (S)
+    pub currentline: c_int,              // (l)
+    pub linedefined: c_int,              // (S)
+    pub lastlinedefined: c_int,          // (S)
+    pub nups: c_uchar,                   // (u) number of upvalues
+    pub nparams: c_uchar,                // (u) number of parameters
+    pub isvararg: c_char,                // (u)
+    pub extraargs: c_uchar,              // (t) number of extra arguments
+    pub istailcall: c_char,              // (t)
+    pub ftransfer: c_int,                // (r) index of first value transferred
+    pub ntransfer: c_int,                // (r) number of transferred values
+    pub short_src: [c_char; LUA_IDSIZE], // (S)
+    // lua.h mentions this is for private use
+    i_ci: *mut c_void,
+}
@@ -0,0 +1,55 @@
+//! Contains definitions from `lualib.h`.
+
+use std::os::raw::{c_char, c_int};
+
+use super::lua::lua_State;
+
+pub const LUA_GLIBK: c_int = 1;
+
+pub const LUA_LOADLIBNAME: *const c_char = cstr!("package");
+pub const LUA_LOADLIBK: c_int = LUA_GLIBK << 1;
+
+pub const LUA_COLIBNAME: *const c_char = cstr!("coroutine");
+pub const LUA_COLIBK: c_int = LUA_GLIBK << 2;
+
+pub const LUA_DBLIBNAME: *const c_char = cstr!("debug");
+pub const LUA_DBLIBK: c_int = LUA_GLIBK << 3;
+
+pub const LUA_IOLIBNAME: *const c_char = cstr!("io");
+pub const LUA_IOLIBK: c_int = LUA_GLIBK << 4;
+
+pub const LUA_MATHLIBNAME: *const c_char = cstr!("math");
+pub const LUA_MATHLIBK: c_int = LUA_GLIBK << 5;
+
+pub const LUA_OSLIBNAME: *const c_char = cstr!("os");
+pub const LUA_OSLIBK: c_int = LUA_GLIBK << 6;
+
+pub const LUA_STRLIBNAME: *const c_char = cstr!("string");
+pub const LUA_STRLIBK: c_int = LUA_GLIBK << 7;
+
+pub const LUA_TABLIBNAME: *const c_char = cstr!("table");
+pub const LUA_TABLIBK: c_int = LUA_GLIBK << 8;
+
+pub const LUA_UTF8LIBNAME: *const c_char = cstr!("utf8");
+pub const LUA_UTF8LIBK: c_int = LUA_GLIBK << 9;
+
+#[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]
+unsafe extern "C-unwind" {
+    pub fn luaopen_base(L: *mut lua_State) -> c_int;
+    pub fn luaopen_package(L: *mut lua_State) -> c_int;
+    pub fn luaopen_coroutine(L: *mut lua_State) -> c_int;
+    pub fn luaopen_debug(L: *mut lua_State) -> c_int;
+    pub fn luaopen_io(L: *mut lua_State) -> c_int;
+    pub fn luaopen_math(L: *mut lua_State) -> c_int;
+    pub fn luaopen_os(L: *mut lua_State) -> c_int;
+    pub fn luaopen_string(L: *mut lua_State) -> c_int;
+    pub fn luaopen_table(L: *mut lua_State) -> c_int;
+    pub fn luaopen_utf8(L: *mut lua_State) -> c_int;
+
+    // open all builtin libraries
+    pub fn luaL_openselectedlibs(L: *mut lua_State, load: c_int, preload: c_int);
+}
+
+pub unsafe fn luaL_openlibs(L: *mut lua_State) {
+    luaL_openselectedlibs(L, !0, 0);
+}
@@ -0,0 +1,9 @@
+//! Low level bindings to Lua 5.5.
+
+pub use lauxlib::*;
+pub use lua::*;
+pub use lualib::*;
+
+pub mod lauxlib;
+pub mod lua;
+pub mod lualib;
@@ -3,7 +3,7 @@
 use std::os::raw::{c_char, c_float, c_int, c_void};
 use std::ptr;

-use super::lua::{self, lua_CFunction, lua_Number, lua_State, lua_Unsigned, LUA_REGISTRYINDEX};
+use super::lua::{self, LUA_REGISTRYINDEX, lua_CFunction, lua_Number, lua_State, lua_Unsigned};

 // Key, in the registry, for table of loaded modules
 pub const LUA_LOADED_TABLE: *const c_char = cstr!("_LOADED");
@@ -38,8 +38,10 @@ unsafe extern "C-unwind" {

    #[link_name = "luaL_checkinteger"]
    pub fn luaL_checkinteger_(L: *mut lua_State, narg: c_int) -> c_int;
+    pub fn luaL_checkinteger64(L: *mut lua_State, narg: c_int) -> i64;
    #[link_name = "luaL_optinteger"]
    pub fn luaL_optinteger_(L: *mut lua_State, narg: c_int, def: c_int) -> c_int;
+    pub fn luaL_optinteger64(L: *mut lua_State, narg: c_int, def: i64) -> i64;
    pub fn luaL_checkunsigned(L: *mut lua_State, narg: c_int) -> lua_Unsigned;
    pub fn luaL_optunsigned(L: *mut lua_State, narg: c_int, def: lua_Unsigned) -> lua_Unsigned;

@@ -85,6 +87,9 @@ unsafe extern "C-unwind" {

    pub fn luaL_callyieldable(L: *mut lua_State, nargs: c_int, nresults: c_int) -> c_int;

+    #[link_name = "luaL_traceback"]
+    pub fn luaL_traceback_(L: *mut lua_State, L1: *mut lua_State, msg: *const c_char, level: c_int);
+
    // sandbox libraries and globals
    #[link_name = "luaL_sandbox"]
    pub fn luaL_sandbox_(L: *mut lua_State);
@@ -119,7 +124,19 @@ pub unsafe fn luaL_optstring(L: *mut lua_State, n: c_int, d: *const c_char) -> *
    luaL_optlstring(L, n, d, ptr::null_mut())
 }

-// TODO: luaL_opt
+#[inline(always)]
+pub unsafe fn luaL_opt<T>(
+    L: *mut lua_State,
+    f: unsafe extern "C-unwind" fn(*mut lua_State, c_int) -> T,
+    n: c_int,
+    d: T,
+) -> T {
+    if lua::lua_isnoneornil(L, n) != 0 {
+        d
+    } else {
+        f(L, n)
+    }
+}

 #[inline(always)]
 pub unsafe fn luaL_getmetatable(L: *mut lua_State, n: *const c_char) -> c_int {
@@ -37,6 +37,16 @@ pub const LUA_ERRRUN: c_int = 2;
 pub const LUA_ERRSYNTAX: c_int = 3;
 pub const LUA_ERRMEM: c_int = 4;
 pub const LUA_ERRERR: c_int = 5;
+pub const LUA_BREAK: c_int = 6; // yielded for a debug breakpoint
+
+//
+// Coroutine status
+//
+pub const LUA_CORUN: c_int = 0; // running
+pub const LUA_COSUS: c_int = 1; // suspended
+pub const LUA_CONOR: c_int = 2; // 'normal' (it resumed another coroutine)
+pub const LUA_COFIN: c_int = 3; // finished
+pub const LUA_COERR: c_int = 4; // finished with error

 /// A raw Lua state associated with a thread.
 #[repr(C)]
@@ -55,14 +65,15 @@ pub const LUA_TBOOLEAN: c_int = 1;

 pub const LUA_TLIGHTUSERDATA: c_int = 2;
 pub const LUA_TNUMBER: c_int = 3;
-pub const LUA_TVECTOR: c_int = 4;
+pub const LUA_TINTEGER: c_int = 4;
+pub const LUA_TVECTOR: c_int = 5;

-pub const LUA_TSTRING: c_int = 5;
-pub const LUA_TTABLE: c_int = 6;
-pub const LUA_TFUNCTION: c_int = 7;
-pub const LUA_TUSERDATA: c_int = 8;
-pub const LUA_TTHREAD: c_int = 9;
-pub const LUA_TBUFFER: c_int = 10;
+pub const LUA_TSTRING: c_int = 6;
+pub const LUA_TTABLE: c_int = 7;
+pub const LUA_TFUNCTION: c_int = 8;
+pub const LUA_TUSERDATA: c_int = 9;
+pub const LUA_TTHREAD: c_int = 10;
+pub const LUA_TBUFFER: c_int = 11;

 /// Guaranteed number of Lua stack slots available to a C function.
 pub const LUA_MINSTACK: c_int = 20;
@@ -143,10 +154,18 @@ unsafe extern "C-unwind" {
    pub fn lua_tounsignedx(L: *mut lua_State, idx: c_int, isnum: *mut c_int) -> lua_Unsigned;
    pub fn lua_tovector(L: *mut lua_State, idx: c_int) -> *const c_float;
    pub fn lua_toboolean(L: *mut lua_State, idx: c_int) -> c_int;
+    pub fn lua_tointeger64(L: *mut lua_State, idx: c_int, isinteger: *mut c_int) -> i64;
    pub fn lua_tolstring(L: *mut lua_State, idx: c_int, len: *mut usize) -> *const c_char;
    pub fn lua_tostringatom(L: *mut lua_State, idx: c_int, atom: *mut c_int) -> *const c_char;
+    pub fn lua_tolstringatom(
+        L: *mut lua_State,
+        idx: c_int,
+        len: *mut usize,
+        atom: *mut c_int,
+    ) -> *const c_char;
    pub fn lua_namecallatom(L: *mut lua_State, atom: *mut c_int) -> *const c_char;
-    pub fn lua_objlen(L: *mut lua_State, idx: c_int) -> usize;
+    #[link_name = "lua_objlen"]
+    pub fn lua_objlen_(L: *mut lua_State, idx: c_int) -> c_int;
    pub fn lua_tocfunction(L: *mut lua_State, idx: c_int) -> Option<lua_CFunction>;
    pub fn lua_tolightuserdata(L: *mut lua_State, idx: c_int) -> *mut c_void;
    pub fn lua_tolightuserdatatagged(L: *mut lua_State, idx: c_int, tag: c_int) -> *mut c_void;
@@ -165,6 +184,7 @@ unsafe extern "C-unwind" {
    pub fn lua_pushnumber(L: *mut lua_State, n: lua_Number);
    #[link_name = "lua_pushinteger"]
    pub fn lua_pushinteger_(L: *mut lua_State, n: c_int);
+    pub fn lua_pushinteger64(L: *mut lua_State, n: i64);
    pub fn lua_pushunsigned(L: *mut lua_State, n: lua_Unsigned);
    #[cfg(not(feature = "luau-vector4"))]
    pub fn lua_pushvector(L: *mut lua_State, x: c_float, y: c_float, z: c_float);
@@ -218,6 +238,7 @@ unsafe extern "C-unwind" {
    //
    pub fn lua_settable(L: *mut lua_State, idx: c_int);
    pub fn lua_setfield(L: *mut lua_State, idx: c_int, k: *const c_char);
+    pub fn lua_rawsetfield(L: *mut lua_State, idx: c_int, k: *const c_char);
    pub fn lua_rawset(L: *mut lua_State, idx: c_int);
    #[link_name = "lua_rawseti"]
    pub fn lua_rawseti_(L: *mut lua_State, idx: c_int, n: c_int);
@@ -251,6 +272,12 @@ unsafe extern "C-unwind" {
    pub fn lua_isyieldable(L: *mut lua_State) -> c_int;
    pub fn lua_getthreaddata(L: *mut lua_State) -> *mut c_void;
    pub fn lua_setthreaddata(L: *mut lua_State, data: *mut c_void);
+    pub fn lua_costatus(L: *mut lua_State, co: *mut lua_State) -> c_int;
+}
+
+#[inline(always)]
+pub unsafe fn lua_objlen(L: *mut lua_State, idx: c_int) -> usize {
+    lua_objlen_(L, idx) as usize
 }

 //
@@ -287,7 +314,7 @@ unsafe extern "C-unwind" {
    pub fn lua_next(L: *mut lua_State, idx: c_int) -> c_int;
    pub fn lua_rawiter(L: *mut lua_State, idx: c_int, iter: c_int) -> c_int;
    pub fn lua_concat(L: *mut lua_State, n: c_int);
-    // TODO: lua_encodepointer
+    pub fn lua_encodepointer(L: *mut lua_State, p: usize) -> usize;
    pub fn lua_clock() -> c_double;
    pub fn lua_setuserdatatag(L: *mut lua_State, idx: c_int, tag: c_int);
    pub fn lua_setuserdatadtor(L: *mut lua_State, tag: c_int, dtor: Option<lua_Destructor>);
@@ -298,6 +325,7 @@ unsafe extern "C-unwind" {
    pub fn lua_getlightuserdataname(L: *mut lua_State, tag: c_int) -> *const c_char;
    pub fn lua_clonefunction(L: *mut lua_State, idx: c_int);
    pub fn lua_cleartable(L: *mut lua_State, idx: c_int);
+    pub fn lua_clonetable(L: *mut lua_State, idx: c_int);
    pub fn lua_getallocf(L: *mut lua_State, ud: *mut *mut c_void) -> lua_Alloc;
 }

@@ -357,7 +385,10 @@ pub unsafe fn lua_newuserdata_t<T>(L: *mut lua_State, data: T) -> *mut T {
    ud_ptr
 }

-// TODO: lua_strlen
+#[inline(always)]
+pub unsafe fn lua_strlen(L: *mut lua_State, i: c_int) -> usize {
+    lua_objlen(L, i)
+}

 #[inline(always)]
 pub unsafe fn lua_isfunction(L: *mut lua_State, n: c_int) -> c_int {
@@ -384,6 +415,11 @@ pub unsafe fn lua_isboolean(L: *mut lua_State, n: c_int) -> c_int {
    (lua_type(L, n) == LUA_TBOOLEAN) as c_int
 }

+#[inline(always)]
+pub unsafe fn lua_isinteger64(L: *mut lua_State, n: c_int) -> c_int {
+    (lua_type(L, n) == LUA_TINTEGER) as c_int
+}
+
 #[inline(always)]
 pub unsafe fn lua_isvector(L: *mut lua_State, n: c_int) -> c_int {
    (lua_type(L, n) == LUA_TVECTOR) as c_int
@@ -473,6 +509,12 @@ pub type lua_Coverage = unsafe extern "C-unwind" fn(
    size: usize,
 );

+pub type lua_CounterFunction =
+    unsafe extern "C-unwind" fn(context: *mut c_void, function: *const c_char, linedefined: c_int);
+
+pub type lua_CounterValue =
+    unsafe extern "C-unwind" fn(context: *mut c_void, kind: c_int, line: c_int, hits: u64);
+
 unsafe extern "C-unwind" {
    pub fn lua_stackdepth(L: *mut lua_State) -> c_int;
    pub fn lua_getinfo(L: *mut lua_State, level: c_int, what: *const c_char, ar: *mut lua_Debug) -> c_int;
@@ -487,6 +529,14 @@ unsafe extern "C-unwind" {

    pub fn lua_getcoverage(L: *mut lua_State, funcindex: c_int, context: *mut c_void, callback: lua_Coverage);

+    pub fn lua_getcounters(
+        L: *mut lua_State,
+        funcindex: c_int,
+        context: *mut c_void,
+        functionvisit: lua_CounterFunction,
+        countervisit: lua_CounterValue,
+    );
+
    pub fn lua_debugtrace(L: *mut lua_State) -> *const c_char;
 }

@@ -523,8 +573,8 @@ pub struct lua_Callbacks {

    /// gets called when L is created (LP == parent) or destroyed (LP == NULL)
    pub userthread: Option<unsafe extern "C-unwind" fn(LP: *mut lua_State, L: *mut lua_State)>,
-    /// gets called when a string is created; returned atom can be retrieved via tostringatom
-    pub useratom: Option<unsafe extern "C-unwind" fn(s: *const c_char, l: usize) -> i16>,
+    /// gets called when a string is created to assign an atom id
+    pub useratom: Option<unsafe extern "C-unwind" fn(L: *mut lua_State, s: *const c_char, l: usize) -> i16>,

    /// gets called when BREAK instruction is encountered
    pub debugbreak: Option<unsafe extern "C-unwind" fn(L: *mut lua_State, ar: *mut lua_Debug)>,
@@ -80,6 +80,7 @@ unsafe extern "C" {
    pub fn luau_set_compile_constant_nil(cons: *mut lua_CompileConstant);
    pub fn luau_set_compile_constant_boolean(cons: *mut lua_CompileConstant, b: c_int);
    pub fn luau_set_compile_constant_number(cons: *mut lua_CompileConstant, n: f64);
+    pub fn luau_set_compile_constant_integer64(cons: *mut lua_CompileConstant, l: i64);
    pub fn luau_set_compile_constant_vector(cons: *mut lua_CompileConstant, x: f32, y: f32, z: f32, w: f32);
    pub fn luau_set_compile_constant_string(cons: *mut lua_CompileConstant, s: *const c_char, l: usize);
 }
@@ -14,6 +14,7 @@ pub const LUA_UTF8LIBNAME: *const c_char = cstr!("utf8");
 pub const LUA_MATHLIBNAME: *const c_char = cstr!("math");
 pub const LUA_DBLIBNAME: *const c_char = cstr!("debug");
 pub const LUA_VECLIBNAME: *const c_char = cstr!("vector");
+pub const LUA_INTLIBNAME: *const c_char = cstr!("integer");

 unsafe extern "C-unwind" {
    pub fn luaopen_base(L: *mut lua_State) -> c_int;
@@ -27,6 +28,7 @@ unsafe extern "C-unwind" {
    pub fn luaopen_math(L: *mut lua_State) -> c_int;
    pub fn luaopen_debug(L: *mut lua_State) -> c_int;
    pub fn luaopen_vector(L: *mut lua_State) -> c_int;
+    pub fn luaopen_integer(L: *mut lua_State) -> c_int;

    // open all builtin libraries
    pub fn luaL_openlibs(L: *mut lua_State);
@@ -58,6 +58,18 @@ pub struct luarequire_Configuration {
        path: *const c_char,
    ) -> luarequire_NavigateResult,

+    // Provides an initial alias override opportunity prior to searching for configuration files.
+    // If NAVIGATE_SUCCESS is returned, the internal state must be updated to point at the
+    // aliased location.
+    // Can be left undefined.
+    pub to_alias_override: Option<
+        unsafe extern "C-unwind" fn(
+            L: *mut lua_State,
+            ctx: *mut c_void,
+            alias_unprefixed: *const c_char,
+        ) -> luarequire_NavigateResult,
+    >,
+
    // Provides a final override opportunity if an alias cannot be found in configuration files. If
    // NAVIGATE_SUCCESS is returned, this must update the internal state to point at the aliased module.
    // Can be left undefined.
@@ -1,8 +1,9 @@
 [package]
 name = "mlua_derive"
-version = "0.11.0"
+version = "0.12.0-rc.1"
 authors = ["Aleksandr Orlenko <zxteam@pm.me>"]
-edition = "2021"
+rust-version = "1.88"
+edition = "2024"
 description = "Procedural macros for the mlua crate."
 repository = "https://github.com/mlua-rs/mlua"
 keywords = ["lua", "mlua"]
@@ -12,7 +13,7 @@ license = "MIT"
 proc-macro = true

 [features]
-macros = ["proc-macro-error2", "itertools", "regex", "once_cell"]
+macros = ["proc-macro-error2", "itertools"]

 [dependencies]
 quote = "1.0"
@@ -20,5 +21,3 @@ proc-macro2 = { version = "1.0", features = ["span-locations"] }
 proc-macro-error2 = { version = "2.0.1", optional = true }
 syn = { version = "2.0", features = ["full"] }
 itertools = { version = "0.14", optional = true }
-regex = { version = "1.4", optional = true }
-once_cell = { version = "1.0", optional = true }
@@ -1,105 +0,0 @@
-use proc_macro::{TokenStream, TokenTree};
-
-use crate::token::{Pos, Token, Tokens};
-
-#[derive(Debug, Clone)]
-pub(crate) struct Capture {
-    key: Token,
-    rust: TokenTree,
-}
-
-impl Capture {
-    fn new(key: Token, rust: TokenTree) -> Self {
-        Self { key, rust }
-    }
-
-    /// Token string inside `chunk!`
-    pub(crate) fn key(&self) -> &Token {
-        &self.key
-    }
-
-    /// As rust variable, e.g. `x`
-    pub(crate) fn as_rust(&self) -> &TokenTree {
-        &self.rust
-    }
-}
-
-#[derive(Debug)]
-pub(crate) struct Captures(Vec<Capture>);
-
-impl Captures {
-    pub(crate) fn new() -> Self {
-        Self(Vec::new())
-    }
-
-    pub(crate) fn add(&mut self, token: &Token) -> Capture {
-        let tt = token.tree();
-        let key = token.clone();
-
-        match self.0.iter().find(|arg| arg.key() == &key) {
-            Some(arg) => arg.clone(),
-            None => {
-                let arg = Capture::new(key, tt.clone());
-                self.0.push(arg.clone());
-                arg
-            }
-        }
-    }
-
-    pub(crate) fn captures(&self) -> &[Capture] {
-        &self.0
-    }
-}
-
-#[derive(Debug)]
-pub(crate) struct Chunk {
-    source: String,
-    caps: Captures,
-}
-
-impl Chunk {
-    pub(crate) fn new(tokens: TokenStream) -> Self {
-        let tokens = Tokens::retokenize(tokens);
-
-        let mut source = String::new();
-        let mut caps = Captures::new();
-
-        let mut pos: Option<Pos> = None;
-        for t in tokens {
-            if t.is_cap() {
-                caps.add(&t);
-            }
-
-            let (line, col) = (t.start().line, t.start().column);
-            let (prev_line, prev_col) = pos
-                .take()
-                .map(|lc| (lc.line, lc.column))
-                .unwrap_or_else(|| (line, col));
-
-            #[allow(clippy::comparison_chain)]
-            if line > prev_line {
-                source.push('\n');
-            } else if line == prev_line {
-                for _ in 0..col.saturating_sub(prev_col) {
-                    source.push(' ');
-                }
-            }
-            source.push_str(&t.to_string());
-
-            pos = Some(t.end());
-        }
-
-        Self {
-            source: source.trim_end().to_string(),
-            caps,
-        }
-    }
-
-    pub(crate) fn source(&self) -> &str {
-        &self.source
-    }
-
-    pub(crate) fn captures(&self) -> &[Capture] {
-        self.caps.captures()
-    }
-}
@@ -0,0 +1,160 @@
+use std::ops::Deref;
+
+use proc_macro::TokenStream;
+use proc_macro2::TokenStream as TokenStream2;
+use quote::{ToTokens, quote};
+
+use self::token::{Pos, Token, Tokens};
+
+mod token;
+
+#[derive(Debug, Clone)]
+pub(crate) struct Capture(Token);
+
+impl Deref for Capture {
+    type Target = Token;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Capture {
+    fn new(token: &Token) -> Self {
+        Self(token.clone())
+    }
+
+    pub(crate) fn name(&self) -> String {
+        self.0.to_string()
+    }
+}
+
+impl ToTokens for Capture {
+    fn to_tokens(&self, tokens: &mut TokenStream2) {
+        let ts: TokenStream = self.0.tree().clone().into();
+        tokens.extend(TokenStream2::from(ts));
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct Captures(Vec<Capture>);
+
+impl Captures {
+    pub(crate) fn new() -> Self {
+        Self(Vec::new())
+    }
+
+    pub(crate) fn add(&mut self, token: &Token) {
+        if self.0.iter().any(|arg| &**arg == token) {
+            return;
+        }
+        self.0.push(Capture::new(token));
+    }
+
+    pub(crate) fn captures(&self) -> &[Capture] {
+        &self.0
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct Chunk {
+    source: String,
+    caps: Captures,
+}
+
+impl Chunk {
+    pub(crate) fn new(tokens: TokenStream) -> Self {
+        let tokens = Tokens::retokenize(tokens);
+
+        let mut source = String::new();
+        let mut caps = Captures::new();
+
+        let mut prev_end: Option<Pos> = None;
+        for t in tokens {
+            if t.is_cap() {
+                caps.add(&t);
+            }
+
+            let (line, col) = (t.start().line, t.start().column);
+            if let Some(prev) = prev_end {
+                if line > prev.line {
+                    source.push('\n');
+                    source.push_str(&" ".repeat(col.saturating_sub(1)));
+                } else if line == prev.line {
+                    source.push_str(&" ".repeat(col.saturating_sub(prev.column)));
+                }
+            } else {
+                source.push_str(&" ".repeat(col.saturating_sub(1)));
+            }
+            source.push_str(&t.to_string());
+
+            prev_end = Some(t.end());
+        }
+
+        Self {
+            source: source.trim_end().to_string(),
+            caps,
+        }
+    }
+
+    pub(crate) fn captures(&self) -> &[Capture] {
+        self.caps.captures()
+    }
+
+    pub(crate) fn expand(&self) -> TokenStream2 {
+        let source = &self.source;
+
+        let caps_len = self.captures().len();
+        let caps = self.captures().iter().map(|cap| {
+            let cap_name = cap.name();
+            quote! { env.raw_set(#cap_name, #cap)?; }
+        });
+
+        quote! {{
+            use mlua::{AsChunk, ChunkMode, Lua, Result, Table};
+            use ::std::borrow::Cow;
+            use ::std::cell::Cell;
+            use ::std::io::Result as IoResult;
+
+            struct InnerChunk<F: FnOnce(&Lua) -> Result<Table>>(Cell<Option<F>>);
+
+            impl<F> AsChunk for InnerChunk<F>
+            where
+                F: FnOnce(&Lua) -> Result<Table>,
+            {
+                fn environment(&self, lua: &Lua) -> Result<Option<Table>> {
+                    if #caps_len > 0 {
+                        if let Some(make_env) = self.0.take() {
+                            return make_env(lua).map(Some);
+                        }
+                    }
+                    Ok(None)
+                }
+
+                fn mode(&self) -> Option<ChunkMode> {
+                    Some(ChunkMode::Text)
+                }
+
+                fn source<'a>(&self) -> IoResult<Cow<'a, [u8]>> {
+                    Ok(Cow::Borrowed((#source).as_bytes()))
+                }
+            }
+
+            let make_env = move |lua: &Lua| -> Result<Table> {
+                let globals = lua.globals();
+                let env = lua.create_table()?;
+                let meta = lua.create_table()?;
+                meta.raw_set("__index", &globals)?;
+                meta.raw_set("__newindex", &globals)?;
+
+                // Add captured variables
+                #(#caps)*
+
+                env.set_metatable(Some(meta))?;
+                Ok(env)
+            };
+
+            InnerChunk(Cell::new(Some(make_env)))
+        }}
+    }
+}
@@ -3,10 +3,8 @@ use std::fmt::{self, Display, Formatter};
 use std::vec::IntoIter;

 use itertools::Itertools;
-use once_cell::sync::Lazy;
 use proc_macro::{Delimiter, Span, TokenStream, TokenTree};
 use proc_macro2::Span as Span2;
-use regex::Regex;

 #[derive(Clone, Copy, Debug)]
 pub(crate) struct Pos {
@@ -39,46 +37,16 @@ fn span_pos(span: &Span) -> (Pos, Pos) {
    let start = span2.start();
    let end = span2.end();

-    // In stable, line/column information is not provided
-    // and set to 0 (line is 1-indexed)
+    // Rust 1.88 stabilized Span APIs, so this branch must be unreachable
    if start.line == 0 || end.line == 0 {
-        return fallback_span_pos(span);
+        proc_macro_error2::abort_call_site!(
+            "cannot retrieve span location information; mlua requires nightly Rust or stable >= 1.88"
+        );
    }

    (Pos::new(start.line, start.column), Pos::new(end.line, end.column))
 }

-fn parse_pos(span: &Span) -> Option<(usize, usize)> {
-    // Workaround to somehow retrieve location information in span in stable rust :(
-
-    static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"bytes\(([0-9]+)\.\.([0-9]+)\)").unwrap());
-
-    match RE.captures(&format!("{span:?}")) {
-        Some(caps) => match (caps.get(1), caps.get(2)) {
-            (Some(start), Some(end)) => Some((
-                match start.as_str().parse() {
-                    Ok(v) => v,
-                    _ => return None,
-                },
-                match end.as_str().parse() {
-                    Ok(v) => v,
-                    _ => return None,
-                },
-            )),
-            _ => None,
-        },
-        None => None,
-    }
-}
-
-fn fallback_span_pos(span: &Span) -> (Pos, Pos) {
-    let (start, end) = match parse_pos(span) {
-        Some(v) => v,
-        None => proc_macro_error2::abort_call_site!("Cannot retrieve span information; please use nightly"),
-    };
-    (Pos::new(1, start), Pos::new(1, end))
-}
-
 /// Attribute of token.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 enum TokenAttr {
@@ -108,8 +76,9 @@ impl Eq for Token {}
 impl Token {
    fn new(tree: TokenTree) -> Self {
        let (start, end) = span_pos(&tree.span());
+        let source = tree.span().source_text().unwrap_or_else(|| tree.to_string());
        Self {
-            source: tree.to_string(),
+            source,
            start,
            end,
            tree,
@@ -168,14 +137,17 @@ impl Tokens {
        Tokens(
            tt.into_iter()
                .flat_map(Tokens::from)
-                .peekable()
                .batching(|iter| {
-                    // Find variable tokens
+                    // Find variable tokens: `$` + `ident` => `$ident`
                    let t = iter.next()?;
                    if t.is("$") {
-                        // `$` + `ident` => `$ident`
-                        let t = iter.next().expect("$ must trail an identifier");
-                        Some(t.attr(TokenAttr::Cap))
+                        if let Some(next) = iter.next()
+                            && matches!(next.tree, TokenTree::Ident(_))
+                        {
+                            Some(next.attr(TokenAttr::Cap))
+                        } else {
+                            proc_macro_error2::abort!(t.tree.span(), "`$` must be followed by an identifier");
+                        }
                    } else {
                        Some(t)
                    }
@@ -1,6 +1,6 @@
 use proc_macro::TokenStream;
 use quote::quote;
-use syn::{parse_macro_input, DeriveInput};
+use syn::{DeriveInput, parse_macro_input};

 pub fn from_lua(input: TokenStream) -> TokenStream {
    let DeriveInput { ident, generics, .. } = parse_macro_input!(input as DeriveInput);
@@ -13,19 +13,19 @@ pub fn from_lua(input: TokenStream) -> TokenStream {
    };

    quote! {
-      impl #impl_generics ::mlua::FromLua for #ident #ty_generics #where_clause {
-        #[inline]
-        fn from_lua(value: ::mlua::Value, _: &::mlua::Lua) -> ::mlua::Result<Self> {
-          match value {
-            ::mlua::Value::UserData(ud) => Ok(ud.borrow::<Self>()?.clone()),
-            _ => Err(::mlua::Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: #ident_str.to_string(),
-                message: None,
-            }),
-          }
+        impl #impl_generics ::mlua::FromLua for #ident #ty_generics #where_clause {
+            #[inline]
+            fn from_lua(value: ::mlua::Value, _: &::mlua::Lua) -> ::mlua::Result<Self> {
+                match value {
+                    ::mlua::Value::UserData(ud) => Ok(ud.borrow::<Self>()?.clone()),
+                    _ => Err(::mlua::Error::FromLuaConversionError {
+                        from: value.type_name(),
+                        to: #ident_str.to_string(),
+                        message: None,
+                    }),
+                }
+            }
        }
-      }
    }
    .into()
 }
@@ -1,148 +1,30 @@
 use proc_macro::TokenStream;
-use proc_macro2::{Ident, Span};
-use quote::quote;
-use syn::meta::ParseNestedMeta;
-use syn::{parse_macro_input, ItemFn, LitStr, Result};
+
+mod module;

 #[cfg(feature = "macros")]
-use {
-    crate::chunk::Chunk, proc_macro::TokenTree, proc_macro2::TokenStream as TokenStream2,
-    proc_macro_error2::proc_macro_error,
-};
+use {crate::chunk::Chunk, proc_macro_error2::proc_macro_error};

-#[derive(Default)]
-struct ModuleAttributes {
-    name: Option<Ident>,
-    skip_memory_check: bool,
-}
-
-impl ModuleAttributes {
-    fn parse(&mut self, meta: ParseNestedMeta) -> Result<()> {
-        if meta.path.is_ident("name") {
-            match meta.value() {
-                Ok(value) => {
-                    self.name = Some(value.parse::<LitStr>()?.parse()?);
-                }
-                Err(_) => {
-                    return Err(meta.error("`name` attribute must have a value"));
-                }
-            }
-        } else if meta.path.is_ident("skip_memory_check") {
-            if meta.value().is_ok() {
-                return Err(meta.error("`skip_memory_check` attribute have no values"));
-            }
-            self.skip_memory_check = true;
-        } else {
-            return Err(meta.error("unsupported module attribute"));
+#[cfg(feature = "macros")]
+macro_rules! try_compile {
+    ($expr:expr) => {
+        match $expr {
+            Ok(val) => val,
+            Err(err) => return err.to_compile_error().into(),
        }
-        Ok(())
-    }
+    };
 }

 #[proc_macro_attribute]
 pub fn lua_module(attr: TokenStream, item: TokenStream) -> TokenStream {
-    let mut args = ModuleAttributes::default();
-    if !attr.is_empty() {
-        let args_parser = syn::meta::parser(|meta| args.parse(meta));
-        parse_macro_input!(attr with args_parser);
-    }
-
-    let func = parse_macro_input!(item as ItemFn);
-    let func_name = &func.sig.ident;
-    let module_name = args.name.unwrap_or_else(|| func_name.clone());
-    let ext_entrypoint_name = Ident::new(&format!("luaopen_{module_name}"), Span::call_site());
-    let skip_memory_check = if args.skip_memory_check {
-        quote! { lua.skip_memory_check(true); }
-    } else {
-        quote! {}
-    };
-
-    let wrapped = quote! {
-        mlua::require_module_feature!();
-
-        #func
-
-        #[no_mangle]
-        unsafe extern "C-unwind" fn #ext_entrypoint_name(state: *mut mlua::lua_State) -> ::std::os::raw::c_int {
-            mlua::Lua::entrypoint1(state, move |lua| {
-                #skip_memory_check
-                #func_name(lua)
-            })
-        }
-    };
-
-    wrapped.into()
-}
-
-#[cfg(feature = "macros")]
-fn to_ident(tt: &TokenTree) -> TokenStream2 {
-    let s: TokenStream = tt.clone().into();
-    s.into()
+    module::lua_module(attr, item)
 }

 #[cfg(feature = "macros")]
 #[proc_macro]
 #[proc_macro_error]
 pub fn chunk(input: TokenStream) -> TokenStream {
-    let chunk = Chunk::new(input);
-
-    let source = chunk.source();
-
-    let caps_len = chunk.captures().len();
-    let caps = chunk.captures().iter().map(|cap| {
-        let cap_name = cap.as_rust().to_string();
-        let cap = to_ident(cap.as_rust());
-        quote! { env.raw_set(#cap_name, #cap)?; }
-    });
-
-    let wrapped_code = quote! {{
-        use mlua::{AsChunk, ChunkMode, Lua, Result, Table};
-        use ::std::borrow::Cow;
-        use ::std::cell::Cell;
-        use ::std::io::Result as IoResult;
-
-        struct InnerChunk<F: FnOnce(&Lua) -> Result<Table>>(Cell<Option<F>>);
-
-        impl<F> AsChunk for InnerChunk<F>
-        where
-            F: FnOnce(&Lua) -> Result<Table>,
-        {
-            fn environment(&self, lua: &Lua) -> Result<Option<Table>> {
-                if #caps_len > 0 {
-                    if let Some(make_env) = self.0.take() {
-                        return make_env(lua).map(Some);
-                    }
-                }
-                Ok(None)
-            }
-
-            fn mode(&self) -> Option<ChunkMode> {
-                Some(ChunkMode::Text)
-            }
-
-            fn source<'a>(&self) -> IoResult<Cow<'a, [u8]>> {
-                Ok(Cow::Borrowed((#source).as_bytes()))
-            }
-        }
-
-        let make_env = move |lua: &Lua| -> Result<Table> {
-            let globals = lua.globals();
-            let env = lua.create_table()?;
-            let meta = lua.create_table()?;
-            meta.raw_set("__index", &globals)?;
-            meta.raw_set("__newindex", &globals)?;
-
-            // Add captured variables
-            #(#caps)*
-
-            env.set_metatable(Some(meta))?;
-            Ok(env)
-        };
-
-        InnerChunk(Cell::new(Some(make_env)))
-    }};
-
-    wrapped_code.into()
+    Chunk::new(input).expand().into()
 }

 #[cfg(feature = "macros")]
@@ -151,9 +33,23 @@ pub fn from_lua(input: TokenStream) -> TokenStream {
    from_lua::from_lua(input)
 }

+/// Derive macro for implementing `UserData` for a Rust type.
+#[cfg(feature = "macros")]
+#[proc_macro_derive(UserData, attributes(lua))]
+pub fn userdata(item: TokenStream) -> TokenStream {
+    userdata::userdata_type(item)
+}
+
+/// Attribute macro for exposing impl block methods to Lua userdata.
+#[cfg(feature = "macros")]
+#[proc_macro_attribute]
+pub fn userdata_impl(attr: TokenStream, item: TokenStream) -> TokenStream {
+    userdata::userdata_impl::userdata_impl(attr, item)
+}
+
 #[cfg(feature = "macros")]
 mod chunk;
 #[cfg(feature = "macros")]
 mod from_lua;
 #[cfg(feature = "macros")]
-mod token;
+mod userdata;
@@ -0,0 +1,68 @@
+use proc_macro::TokenStream;
+use proc_macro2::{Ident, Span};
+use quote::quote;
+use syn::meta::ParseNestedMeta;
+use syn::{ItemFn, LitStr, Result, parse_macro_input};
+
+#[derive(Default)]
+struct ModuleAttributes {
+    name: Option<Ident>,
+    skip_memory_check: bool,
+}
+
+impl ModuleAttributes {
+    fn parse(&mut self, meta: ParseNestedMeta) -> Result<()> {
+        if meta.path.is_ident("name") {
+            match meta.value() {
+                Ok(value) => {
+                    self.name = Some(value.parse::<LitStr>()?.parse()?);
+                }
+                Err(_) => {
+                    return Err(meta.error("`name` attribute must have a value"));
+                }
+            }
+        } else if meta.path.is_ident("skip_memory_check") {
+            if meta.value().is_ok() {
+                return Err(meta.error("`skip_memory_check` attribute have no values"));
+            }
+            self.skip_memory_check = true;
+        } else {
+            return Err(meta.error("unsupported module attribute"));
+        }
+        Ok(())
+    }
+}
+
+pub fn lua_module(attr: TokenStream, item: TokenStream) -> TokenStream {
+    let mut args = ModuleAttributes::default();
+    if !attr.is_empty() {
+        let args_parser = syn::meta::parser(|meta| args.parse(meta));
+        parse_macro_input!(attr with args_parser);
+    }
+
+    let func = parse_macro_input!(item as ItemFn);
+    let func_name = &func.sig.ident;
+    let module_name = args.name.unwrap_or_else(|| func_name.clone());
+    let ext_entrypoint_name = Ident::new(&format!("luaopen_{module_name}"), Span::call_site());
+    let skip_memory_check = if args.skip_memory_check {
+        quote! { lua.skip_memory_check(true); }
+    } else {
+        quote! {}
+    };
+
+    let wrapped = quote! {
+        mlua::require_module_feature!();
+
+        #func
+
+        #[unsafe(no_mangle)]
+        unsafe extern "C-unwind" fn #ext_entrypoint_name(state: *mut mlua::lua_State) -> ::std::os::raw::c_int {
+            mlua::Lua::entrypoint1(state, move |lua| {
+                #skip_memory_check
+                #func_name(lua)
+            })
+        }
+    };
+
+    wrapped.into()
+}
@@ -0,0 +1,93 @@
+use proc_macro2::Span;
+use syn::meta::ParseNestedMeta;
+use syn::{Ident, LitStr, Result};
+
+/// Parsed `#[lua(...)]` attribute.
+///
+/// Some flags are context-dependent:
+/// - Struct fields: `get`, `set`, `name`, `skip`
+/// - Impl methods: `getter`, `setter`, `field`, `meta`, `infallible`, `name`, `skip`
+#[derive(Default)]
+pub(crate) struct LuaAttr {
+    pub(crate) span: Option<Span>,
+    pub(crate) name: Option<String>,
+    pub(crate) infallible: bool,
+    pub(crate) skip: bool,
+
+    // Struct field context flags
+    pub(crate) get: bool,
+    pub(crate) set: bool,
+
+    // Impl method context flags
+    pub(crate) getter: bool,
+    pub(crate) setter: bool,
+    pub(crate) field: bool,
+    pub(crate) meta: bool,
+}
+
+impl LuaAttr {
+    pub(crate) fn parse_inner(&mut self, meta: ParseNestedMeta) -> Result<()> {
+        match &meta.path {
+            path if path.is_ident("skip") => {
+                if meta.value().is_ok() {
+                    return Err(meta.error("`skip` does not take a value"));
+                }
+                self.skip = true;
+            }
+            path if path.is_ident("infallible") => {
+                if meta.value().is_ok() {
+                    return Err(meta.error("`infallible` does not take a value"));
+                }
+                self.infallible = true;
+            }
+            path if path.is_ident("get") => self.get = true,
+            path if path.is_ident("set") => self.set = true,
+            path if path.is_ident("getter") => self.getter = true,
+            path if path.is_ident("setter") => self.setter = true,
+            path if path.is_ident("field") => self.field = true,
+            path if path.is_ident("meta") => self.meta = true,
+            path if path.is_ident("name") => {
+                let value = meta.value()?;
+                let lit: LitStr = value.parse()?;
+                self.name = Some(lit.value());
+            }
+            _ => {
+                return Err(meta.error(
+                    "unsupported lua attribute, expected: ".to_string()
+                        + "`skip`, `infallible`, `get`, `set`, `getter`, `setter`, `field`, `meta`, `name`",
+                ));
+            }
+        }
+        Ok(())
+    }
+
+    /// Returns the effective Lua name.
+    pub(crate) fn name(&self, ident: &Ident) -> String {
+        self.name.clone().unwrap_or_else(|| ident.to_string())
+    }
+
+    /// Returns the span to use for error reporting.
+    pub(crate) fn span(&self) -> Span {
+        self.span.unwrap_or_else(Span::call_site)
+    }
+
+    /// Returns the effective Lua metamethod name.
+    ///
+    /// If `name` is set via attribute, use it. Otherwise, if the function name
+    /// starts with `__`, use that. Returns an error if neither is available.
+    pub(crate) fn effective_meta_name(&self, fn_ident: &Ident) -> Result<String> {
+        if let Some(ref name) = self.name {
+            return Ok(name.clone());
+        }
+        let fn_name = fn_ident.to_string();
+        if fn_name.starts_with("__") {
+            return Ok(fn_name);
+        }
+        Err(syn::Error::new(
+            fn_ident.span(),
+            format!(
+                "could not infer metamethod name from `{fn_name}`, either add `name = \"...\"` to `#[lua(meta, ...)]` or prefix the function with `__`"
+            ),
+        ))
+    }
+}
@@ -0,0 +1,165 @@
+mod attr;
+pub(crate) mod userdata_impl;
+
+use proc_macro::TokenStream;
+use quote::{format_ident, quote};
+use syn::spanned::Spanned;
+use syn::{Attribute, Data, DeriveInput, Error, Fields, FieldsNamed, Meta, parse_macro_input};
+
+use self::attr::LuaAttr;
+
+/// Wrap registration tokens with any `#[cfg]`/`#[cfg_attr]` attributes from the original item.
+pub(crate) fn with_cfg(tokens: proc_macro2::TokenStream, attrs: &[Attribute]) -> proc_macro2::TokenStream {
+    let cfgs: Vec<_> = (attrs.iter())
+        .filter(|attr| attr.path().is_ident("cfg") || attr.path().is_ident("cfg_attr"))
+        .collect();
+    if cfgs.is_empty() {
+        return tokens;
+    }
+    quote! {
+        #(#cfgs)*
+        #tokens
+    }
+}
+
+/// Parse all `#[lua(...)]` attributes on a field, merging them into one `LuaAttr`.
+fn parse_field_lua_attr(attrs: &[Attribute]) -> syn::Result<LuaAttr> {
+    let mut lua_attr = LuaAttr::default();
+    for attr in attrs {
+        if !attr.path().is_ident("lua") {
+            continue;
+        }
+        match &attr.meta {
+            Meta::List(_) => {
+                lua_attr.span = Some(attr.span());
+                attr.parse_nested_meta(|meta| lua_attr.parse_inner(meta))?;
+                validate_field_lua_attr(&lua_attr)?;
+            }
+            Meta::Path(_) => {}
+            Meta::NameValue(_) => {
+                return Err(syn::Error::new_spanned(
+                    attr,
+                    "`#[lua = \"...\"]` is not supported: use `#[lua(attr = \"...\")]`",
+                ));
+            }
+        }
+    }
+    Ok(lua_attr)
+}
+
+fn validate_field_lua_attr(attr: &LuaAttr) -> syn::Result<()> {
+    for (set, name) in [
+        (attr.getter, "getter"),
+        (attr.setter, "setter"),
+        (attr.field, "field"),
+        (attr.meta, "meta"),
+        (attr.infallible, "infallible"),
+    ] {
+        if set {
+            return Err(syn::Error::new(
+                attr.span(),
+                format!("`{name}` is not valid for struct fields"),
+            ));
+        }
+    }
+    Ok(())
+}
+
+pub fn userdata_type(item: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(item as DeriveInput);
+    let type_name = &input.ident;
+
+    let named_fields: Option<&FieldsNamed> = match &input.data {
+        Data::Struct(data) => match &data.fields {
+            Fields::Named(fields) => Some(fields),
+            Fields::Unnamed(_) | Fields::Unit => None,
+        },
+        Data::Enum(_) => None,
+        Data::Union(_) => {
+            return Error::new_spanned(&input, "`#[derive(UserData)]` cannot be applied to unions")
+                .to_compile_error()
+                .into();
+        }
+    };
+
+    // Check for generic parameters (not supported)
+    let has_generics = !input.generics.params.is_empty();
+    if has_generics {
+        return Error::new_spanned(
+            &input.generics,
+            "`#[derive(UserData)]` does not support generic type parameters. Wrap the generic type in a concrete newtype instead."
+        )
+        .to_compile_error()
+        .into();
+    }
+
+    let mut field_registrations = Vec::new();
+    if let Some(fields) = &named_fields {
+        for field in &fields.named {
+            let field_name = field.ident.as_ref().unwrap();
+
+            let lua_attr = try_compile!(parse_field_lua_attr(&field.attrs));
+            if lua_attr.skip {
+                continue;
+            }
+
+            let lua_name = lua_attr.name.unwrap_or_else(|| field_name.to_string());
+
+            // Assume get/set by default (unless explicitly specified)
+            let (has_get, has_set) = if lua_attr.get || lua_attr.set {
+                (lua_attr.get, lua_attr.set)
+            } else {
+                (true, true)
+            };
+
+            if has_get {
+                let tokens = quote! {
+                    registry.add_field_method_get(#lua_name, |_lua, this| Ok(this.#field_name.clone()));
+                };
+                field_registrations.push(with_cfg(tokens, &field.attrs));
+            }
+            if has_set {
+                let tokens = quote! {
+                    registry.add_field_method_set(#lua_name, |_lua, this, val| {
+                        this.#field_name = val;
+                        Ok(())
+                    });
+                };
+                field_registrations.push(with_cfg(tokens, &field.attrs));
+            }
+        }
+    }
+
+    let registration_type_name = format_ident!("__MluaUserDataRegistration_{type_name}");
+    let register_fields_fn_name = format_ident!("__mlua_register_{type_name}_fields");
+
+    let output = quote! {
+        #[doc(hidden)]
+        #[allow(non_camel_case_types)]
+        struct #registration_type_name {
+            register: fn(&mut ::mlua::userdata::UserDataRegistry<#type_name>),
+        }
+
+        ::mlua::__inventory::collect!(#registration_type_name);
+
+        #[allow(non_snake_case)]
+        fn #register_fields_fn_name(registry: &mut ::mlua::userdata::UserDataRegistry<#type_name>) {
+            use ::mlua::userdata::UserDataFields as _;
+            #(#field_registrations)*
+        }
+
+        ::mlua::__inventory::submit! {
+            #registration_type_name { register: #register_fields_fn_name }
+        }
+
+        impl ::mlua::userdata::UserData for #type_name {
+            fn register(registry: &mut ::mlua::userdata::UserDataRegistry<Self>) {
+                for item in ::mlua::__inventory::iter::<#registration_type_name> {
+                    (item.register)(registry);
+                }
+            }
+        }
+    };
+
+    output.into()
+}
@@ -0,0 +1,730 @@
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use proc_macro::TokenStream;
+use proc_macro2::TokenStream as TokenStream2;
+use quote::{format_ident, quote};
+use syn::spanned::Spanned;
+use syn::{
+    Attribute, FnArg, Ident, ImplItem, ItemImpl, Meta, Signature, Type, parse_macro_input, parse_quote,
+};
+
+use super::attr::LuaAttr;
+use super::with_cfg;
+
+/// `&T` reference types that mlua provides as wrapper types via `FromLua`.
+static BORROW_WRAPPERS: &[(&str, &str)] = &[
+    ("str", "::mlua::string::BorrowedStr"),
+    ("[u8]", "::mlua::string::BorrowedBytes"),
+];
+
+enum SelfKind {
+    Ref(RefKind),
+    Owned,
+    None,
+}
+
+enum RefKind {
+    Ref,
+    Mut,
+}
+
+struct ArgInfo {
+    ident: Ident,
+    userdata_ref: Option<RefKind>,
+    callback_type: Type,
+}
+
+struct MethodInfo {
+    self_kind: SelfKind,
+    has_lua: bool,
+    args: Vec<ArgInfo>,
+}
+
+/// Extract the inner type from a reference type.
+fn ref_inner_type(ty: &Type) -> Type {
+    match ty {
+        Type::Reference(ref_ty) => (*ref_ty.elem).clone(),
+        _ => ty.clone(),
+    }
+}
+
+/// Check if the type is `&Lua` or `&mlua::Lua`.
+fn is_lua_ref(ty: &Type) -> bool {
+    let Type::Reference(ref_ty) = ty else { return false };
+    match &*ref_ty.elem {
+        Type::Path(p) if p.path.segments.len() == 1 => p.path.segments[0].ident == "Lua",
+        Type::Path(p) if p.path.segments.len() == 2 => {
+            p.path.segments[0].ident == "mlua" && p.path.segments[1].ident == "Lua"
+        }
+        _ => false,
+    }
+}
+
+/// Classify a `&[mut] T` parameter, returning the callback wrapper type.
+///
+/// Known borrow types come from the mapping table `BORROW_WRAPPERS`.
+/// Everything else gets `UserDataRef[Mut]<T>`.
+fn classify_ref_type(ty: &Type) -> Option<Type> {
+    let Type::Reference(ref_ty) = ty else { return None };
+
+    // Check known borrow wrappers:
+    // - For `&T` check the path name
+    // - For `&[T]` unpack the slice and format the element as `[T]` for lookup
+    if ref_ty.mutability.is_none() {
+        let lookup_name: Option<String> = match &*ref_ty.elem {
+            Type::Path(path) => path.path.segments.last().map(|seg| seg.ident.to_string()),
+            Type::Slice(slice) => {
+                if let Type::Path(path) = &*slice.elem {
+                    path.path.segments.last().map(|seg| format!("[{}]", seg.ident))
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        };
+        if let Some(ref name) = lookup_name {
+            for &(inner, wrapper) in BORROW_WRAPPERS {
+                if name == inner {
+                    let wrapper = syn::parse_str(wrapper).expect("invalid wrapper type");
+                    return Some(wrapper);
+                }
+            }
+        }
+    }
+    // Mutable references to slices are not supported.
+    if matches!(&*ref_ty.elem, Type::Slice(_)) && ref_ty.mutability.is_some() {
+        return None;
+    }
+
+    let inner = ref_inner_type(ty);
+    if ref_ty.mutability.is_none() {
+        Some(parse_quote! { ::mlua::userdata::UserDataRef<#inner> })
+    } else {
+        Some(parse_quote! { ::mlua::userdata::UserDataRefMut<#inner> })
+    }
+}
+
+/// Analyze method signature.
+///
+/// Determine `self` kind and collect the callback arguments.
+/// Auto-detects `&Lua` as the first non-self parameter.
+fn analyze_self_and_args(sig: &Signature) -> syn::Result<MethodInfo> {
+    let mut self_kind = SelfKind::None;
+    let mut has_lua = false;
+    let mut args = Vec::new();
+    let mut check_first_typed = true;
+
+    for param in &sig.inputs {
+        match param {
+            FnArg::Receiver(recv) if recv.reference.is_some() && recv.mutability.is_some() => {
+                self_kind = SelfKind::Ref(RefKind::Mut);
+            }
+            FnArg::Receiver(recv) if recv.reference.is_some() => {
+                self_kind = SelfKind::Ref(RefKind::Ref);
+            }
+            FnArg::Receiver(_) => {
+                self_kind = SelfKind::Owned;
+            }
+            FnArg::Typed(typed) => {
+                if check_first_typed && is_lua_ref(&typed.ty) {
+                    has_lua = true;
+                    check_first_typed = false;
+                    continue;
+                }
+                check_first_typed = false;
+                if let syn::Pat::Ident(pat_ident) = &*typed.pat {
+                    let arg_type = &*typed.ty;
+                    let ref_kind = match arg_type {
+                        Type::Reference(r) if r.mutability.is_some() => Some(RefKind::Mut),
+                        Type::Reference(_) => Some(RefKind::Ref),
+                        _ => None,
+                    };
+                    let callback_type = match &ref_kind {
+                        Some(_) => match classify_ref_type(arg_type) {
+                            Some(ty) => ty,
+                            None => {
+                                return Err(syn::Error::new_spanned(
+                                    arg_type,
+                                    "this reference type is not supported as a callback parameter",
+                                ));
+                            }
+                        },
+                        None => arg_type.clone(),
+                    };
+                    args.push(ArgInfo {
+                        ident: pat_ident.ident.clone(),
+                        userdata_ref: ref_kind,
+                        callback_type,
+                    });
+                }
+            }
+        }
+    }
+
+    Ok(MethodInfo {
+        self_kind,
+        has_lua,
+        args,
+    })
+}
+
+fn strip_item_attrs(attrs: &[Attribute]) -> Vec<Attribute> {
+    (attrs.iter())
+        .filter(|attr| !attr.path().is_ident("lua"))
+        .cloned()
+        .collect()
+}
+
+fn parse_lua_attr(attrs: &[Attribute]) -> syn::Result<LuaAttr> {
+    let mut lua_attr = LuaAttr::default();
+    for attr in attrs {
+        if !attr.path().is_ident("lua") {
+            continue;
+        }
+        match &attr.meta {
+            Meta::List(_) => {
+                lua_attr.span = Some(attr.span());
+                attr.parse_nested_meta(|meta| lua_attr.parse_inner(meta))?;
+                validate_lua_attr(&lua_attr)?;
+            }
+            Meta::Path(_) => {}
+            Meta::NameValue(_) => {
+                return Err(syn::Error::new_spanned(
+                    attr,
+                    "`#[lua = \"...\"]` is not supported: use `#[lua(attr = \"...\")]`",
+                ));
+            }
+        }
+    }
+    Ok(lua_attr)
+}
+
+fn validate_lua_attr(attr: &LuaAttr) -> syn::Result<()> {
+    for (set, name) in [(attr.get, "get"), (attr.set, "set")] {
+        if set {
+            return Err(syn::Error::new(
+                attr.span(),
+                format!("`{name}` is not valid for methods"),
+            ));
+        }
+    }
+    Ok(())
+}
+
+pub fn userdata_impl(attr: TokenStream, item: TokenStream) -> TokenStream {
+    if !attr.is_empty() {
+        return syn::Error::new_spanned(
+            proc_macro2::TokenStream::from(attr),
+            "`#[userdata_impl]` does not accept arguments",
+        )
+        .to_compile_error()
+        .into();
+    }
+
+    let mut input = parse_macro_input!(item as ItemImpl);
+
+    let type_path = match &*input.self_ty {
+        Type::Path(type_path) => &type_path.path,
+        _ => {
+            return syn::Error::new_spanned(&input.self_ty, "`#[userdata_impl]` requires a simple path type")
+                .to_compile_error()
+                .into();
+        }
+    };
+    let type_name = (type_path.segments)
+        .last()
+        .map(|seg| seg.ident.clone())
+        .ok_or_else(|| syn::Error::new_spanned(&input.self_ty, "cannot determine type name"));
+    let type_name = try_compile!(type_name);
+
+    static COUNTER: AtomicUsize = AtomicUsize::new(0);
+    let unique_suffix = COUNTER.fetch_add(1, Ordering::Relaxed);
+    let register_fn_name = format_ident!("__mlua_register_{type_name}_{unique_suffix}");
+    let registration_type_name = format_ident!("__MluaUserDataRegistration_{type_name}");
+
+    let mut registration_calls = Vec::new();
+    for item in &input.items {
+        match item {
+            ImplItem::Const(const_item) => {
+                let lua_attr = try_compile!(parse_lua_attr(&const_item.attrs));
+                if lua_attr.skip {
+                    continue;
+                }
+                if lua_attr.getter || lua_attr.setter {
+                    return syn::Error::new(
+                        lua_attr.span(),
+                        "const items do not support `getter` or `setter`",
+                    )
+                    .to_compile_error()
+                    .into();
+                }
+                let const_name = &const_item.ident;
+                let lua_name = lua_attr.name(const_name);
+                if lua_attr.meta {
+                    let tokens = quote! {
+                        registry.add_meta_field(#lua_name, #type_path::#const_name);
+                    };
+                    registration_calls.push(with_cfg(tokens, &const_item.attrs));
+                } else {
+                    let tokens = quote! {
+                        registry.add_field(#lua_name, #type_path::#const_name);
+                    };
+                    registration_calls.push(with_cfg(tokens, &const_item.attrs));
+                }
+            }
+            ImplItem::Fn(method) => {
+                let lua_attr = try_compile!(parse_lua_attr(&method.attrs));
+                if lua_attr.skip {
+                    continue;
+                }
+
+                // Validate mutually exclusive role flags.
+                // `getter`, `setter`, `field` are exclusive.
+                // `meta` on its own means a metamethod.
+                // `meta` combined with `field` means a meta static field.
+                // `meta` with `getter` or `setter` is invalid.
+                let primary = [lua_attr.getter, lua_attr.setter, lua_attr.field];
+                let primary_count = primary.iter().filter(|&&x| x).count();
+                if primary_count > 1 {
+                    return syn::Error::new(
+                        lua_attr.span(),
+                        "at most one of `getter`, `setter`, `field` can be specified",
+                    )
+                    .to_compile_error()
+                    .into();
+                }
+                if lua_attr.meta && primary_count == 1 && !lua_attr.field {
+                    return syn::Error::new(lua_attr.span(), "`meta` can only be combined with `field`")
+                        .to_compile_error()
+                        .into();
+                }
+
+                let fn_name = &method.sig.ident;
+                let info = try_compile!(analyze_self_and_args(&method.sig));
+                let is_async = method.sig.asyncness.is_some();
+
+                if lua_attr.getter {
+                    if is_async {
+                        return syn::Error::new_spanned(&method.sig, "async field getter is not supported")
+                            .to_compile_error()
+                            .into();
+                    }
+                    if !matches!(info.self_kind, SelfKind::Ref(RefKind::Ref)) {
+                        return syn::Error::new_spanned(&method.sig, "field getter must take `&self`")
+                            .to_compile_error()
+                            .into();
+                    }
+                    if !info.args.is_empty() {
+                        return syn::Error::new_spanned(
+                            &method.sig,
+                            "field getter must not take additional arguments",
+                        )
+                        .to_compile_error()
+                        .into();
+                    }
+                    let tokens = gen_field_getter(type_path, fn_name, &lua_attr, &info);
+                    registration_calls.push(with_cfg(tokens, &method.attrs));
+                    continue;
+                }
+                if lua_attr.setter {
+                    if is_async {
+                        return syn::Error::new_spanned(&method.sig, "async field setter is not supported")
+                            .to_compile_error()
+                            .into();
+                    }
+                    if !matches!(info.self_kind, SelfKind::Ref(_)) {
+                        return syn::Error::new_spanned(&method.sig, "field setter must take `&[mut] self`")
+                            .to_compile_error()
+                            .into();
+                    }
+                    if info.args.len() != 1 {
+                        return syn::Error::new_spanned(
+                            &method.sig,
+                            "field setter must take exactly one value argument",
+                        )
+                        .to_compile_error()
+                        .into();
+                    }
+                    let tokens = gen_field_setter(type_path, fn_name, &lua_attr, &info);
+                    registration_calls.push(with_cfg(tokens, &method.attrs));
+                    continue;
+                }
+                if lua_attr.field {
+                    if is_async {
+                        return syn::Error::new_spanned(&method.sig, "async field function is not supported")
+                            .to_compile_error()
+                            .into();
+                    }
+                    if !matches!(info.self_kind, SelfKind::None) {
+                        return syn::Error::new_spanned(&method.sig, "field function must not take `self`")
+                            .to_compile_error()
+                            .into();
+                    }
+                    if !info.args.is_empty() {
+                        return syn::Error::new_spanned(
+                            &method.sig,
+                            "field function must not take arguments",
+                        )
+                        .to_compile_error()
+                        .into();
+                    }
+                    let lua_name = lua_attr.name(fn_name);
+                    if lua_attr.meta {
+                        let tokens = quote! {
+                            registry.add_meta_field(#lua_name, #type_path::#fn_name());
+                        };
+                        registration_calls.push(with_cfg(tokens, &method.attrs));
+                    } else {
+                        let tokens = quote! {
+                            registry.add_field(#lua_name, #type_path::#fn_name());
+                        };
+                        registration_calls.push(with_cfg(tokens, &method.attrs));
+                    }
+                    continue;
+                }
+
+                if lua_attr.meta {
+                    if matches!(info.self_kind, SelfKind::Owned) {
+                        return syn::Error::new_spanned(
+                            &method.sig,
+                            "meta methods cannot take `self`, use `&[mut] self` instead",
+                        )
+                        .to_compile_error()
+                        .into();
+                    }
+                    if is_async {
+                        let tokens = gen_async_meta(type_path, fn_name, &lua_attr, &info);
+                        registration_calls.push(with_cfg(tokens, &method.attrs));
+                    } else {
+                        let tokens = gen_meta(type_path, fn_name, &lua_attr, &info);
+                        registration_calls.push(with_cfg(tokens, &method.attrs));
+                    }
+                    continue;
+                }
+
+                if is_async {
+                    let tokens = gen_async_regular_method(type_path, fn_name, &lua_attr, &info);
+                    registration_calls.push(with_cfg(tokens, &method.attrs));
+                } else {
+                    let tokens = gen_regular_method(type_path, fn_name, &lua_attr, &info);
+                    registration_calls.push(with_cfg(tokens, &method.attrs));
+                }
+            }
+            _ => {}
+        }
+    }
+
+    for item in &mut input.items {
+        match item {
+            ImplItem::Const(c) => c.attrs = strip_item_attrs(&c.attrs),
+            ImplItem::Fn(m) => m.attrs = strip_item_attrs(&m.attrs),
+            _ => {}
+        }
+    }
+    input.attrs = strip_item_attrs(&input.attrs);
+
+    let output = quote! {
+        #[allow(non_snake_case)]
+        fn #register_fn_name(registry: &mut ::mlua::userdata::UserDataRegistry<#type_path>) {
+            use ::mlua::userdata::{UserDataFields as _, UserDataMethods as _};
+            #(#registration_calls)*
+        }
+
+        ::mlua::__inventory::submit! {
+            #registration_type_name { register: #register_fn_name }
+        }
+
+        #input
+    };
+
+    output.into()
+}
+
+/// Generate the closure argument destructuring pattern.
+fn gen_closure_destructure(info: &MethodInfo) -> TokenStream2 {
+    if info.args.is_empty() {
+        return quote! { () };
+    }
+    let idents: Vec<_> = (info.args)
+        .iter()
+        .map(|a| {
+            let ident = &a.ident;
+            if matches!(a.userdata_ref, Some(RefKind::Mut)) {
+                quote! { mut #ident }
+            } else {
+                quote! { #ident }
+            }
+        })
+        .collect();
+    let types: Vec<_> = info.args.iter().map(|a| &a.callback_type).collect();
+    quote! { (#(#idents),*): (#(#types),*) }
+}
+
+/// Generate call arguments for invoking the original method.
+fn gen_call_args(info: &MethodInfo) -> TokenStream2 {
+    let mut call_args: Vec<TokenStream2> = Vec::new();
+
+    match info.self_kind {
+        SelfKind::None => {}
+        _ => call_args.push(quote! { this }),
+    }
+
+    if info.has_lua {
+        call_args.push(quote! { lua });
+    }
+
+    for arg in &info.args {
+        let ident = &arg.ident;
+        match arg.userdata_ref {
+            Some(RefKind::Ref) => call_args.push(quote! { &*#ident }),
+            Some(RefKind::Mut) => call_args.push(quote! { &mut *#ident }),
+            None => call_args.push(quote! { #ident }),
+        }
+    }
+
+    quote! { #(#call_args),* }
+}
+
+/// Generate call arguments for invoking the original async method.
+fn gen_async_call_args(info: &MethodInfo) -> TokenStream2 {
+    let mut call_args: Vec<TokenStream2> = Vec::new();
+
+    match info.self_kind {
+        SelfKind::None => {}
+        SelfKind::Ref(RefKind::Ref) => call_args.push(quote! { &this }),
+        SelfKind::Ref(RefKind::Mut) => call_args.push(quote! { &mut this }),
+        SelfKind::Owned => call_args.push(quote! { this }),
+    }
+
+    if info.has_lua {
+        call_args.push(quote! { lua });
+    }
+
+    for arg in &info.args {
+        let ident = &arg.ident;
+        match arg.userdata_ref {
+            Some(RefKind::Ref) => call_args.push(quote! { &*#ident }),
+            Some(RefKind::Mut) => call_args.push(quote! { &mut *#ident }),
+            None => call_args.push(quote! { #ident }),
+        }
+    }
+
+    quote! { #(#call_args),* }
+}
+
+/// Generate the closure params for the registration callback.
+fn gen_closure_params(info: &MethodInfo) -> TokenStream2 {
+    let destructure = gen_closure_destructure(info);
+    match info.self_kind {
+        SelfKind::None => quote! { |lua, #destructure| },
+        _ => quote! { |lua, this, #destructure| },
+    }
+}
+
+/// Generate the closure params for an async registration callback.
+fn gen_async_closure_params(info: &MethodInfo) -> TokenStream2 {
+    let destructure = gen_closure_destructure(info);
+    match info.self_kind {
+        SelfKind::None => quote! { |lua, #destructure| },
+        SelfKind::Ref(RefKind::Mut) => quote! { |lua, mut this, #destructure| },
+        _ => quote! { |lua, this, #destructure| },
+    }
+}
+
+fn gen_field_getter(
+    type_path: &syn::Path,
+    fn_name: &Ident,
+    lua_attr: &LuaAttr,
+    info: &MethodInfo,
+) -> TokenStream2 {
+    let lua_name = lua_attr.name(fn_name);
+    let call_args = gen_call_args(info);
+
+    if lua_attr.infallible {
+        return quote! {
+            registry.add_field_method_get(#lua_name, |lua, this| {
+                let _ = lua; // silence unused variable warning
+                Ok(#type_path::#fn_name(#call_args))
+            });
+        };
+    }
+
+    quote! {
+        registry.add_field_method_get(#lua_name, |lua, this| {
+            let _ = lua; // silence unused variable warning
+            #type_path::#fn_name(#call_args)
+        });
+    }
+}
+
+fn gen_field_setter(
+    type_path: &syn::Path,
+    fn_name: &Ident,
+    lua_attr: &LuaAttr,
+    info: &MethodInfo,
+) -> TokenStream2 {
+    let lua_name = lua_attr.name(fn_name);
+    let call_args = gen_call_args(info);
+
+    if lua_attr.infallible {
+        let val_ident = info.args.first().map(|a| &a.ident);
+        return quote! {
+            registry.add_field_method_set(#lua_name, |lua, this, #val_ident| {
+                let _ = lua; // silence unused variable warning
+                Ok(#type_path::#fn_name(#call_args))
+            });
+        };
+    }
+
+    let val_ident = info.args.first().map(|a| &a.ident);
+    quote! {
+        registry.add_field_method_set(#lua_name, |lua, this, #val_ident| {
+            let _ = lua; // silence unused variable warning
+            #type_path::#fn_name(#call_args)
+        });
+    }
+}
+
+fn gen_meta(type_path: &syn::Path, fn_name: &Ident, lua_attr: &LuaAttr, info: &MethodInfo) -> TokenStream2 {
+    let meta_name = match lua_attr.effective_meta_name(fn_name) {
+        Ok(name) => name,
+        Err(err) => return err.to_compile_error(),
+    };
+    let closure_params = if matches!(info.self_kind, SelfKind::None) {
+        // Lua always passes `self` to the stack arg, just ignore it.
+        if info.args.is_empty() {
+            quote! { |lua, _this: ::mlua::AnyUserData| }
+        } else {
+            let idents: Vec<_> = info.args.iter().map(|a| &a.ident).collect();
+            let types: Vec<_> = info.args.iter().map(|a| &a.callback_type).collect();
+            quote! { |lua, (_this, #(#idents),*): (::mlua::AnyUserData, #(#types),*) | }
+        }
+    } else {
+        gen_closure_params(info)
+    };
+    let call_args = gen_call_args(info);
+    let fn_path = quote! { #type_path::#fn_name };
+
+    let body = if lua_attr.infallible {
+        quote! { Ok(#fn_path(#call_args)) }
+    } else {
+        quote! { #fn_path(#call_args) }
+    };
+    match info.self_kind {
+        SelfKind::None => quote! {
+            registry.add_meta_function(#meta_name, #closure_params { #body });
+        },
+        SelfKind::Ref(RefKind::Mut) => quote! {
+            registry.add_meta_method_mut(#meta_name, #closure_params { #body });
+        },
+        _ => quote! {
+            registry.add_meta_method(#meta_name, #closure_params { #body });
+        },
+    }
+}
+
+fn gen_regular_method(
+    type_path: &syn::Path,
+    fn_name: &Ident,
+    lua_attr: &LuaAttr,
+    info: &MethodInfo,
+) -> TokenStream2 {
+    let fn_path = quote! { #type_path::#fn_name };
+    let closure_params = gen_closure_params(info);
+    let call_args = gen_call_args(info);
+    let lua_name = lua_attr.name(fn_name);
+
+    let body = if lua_attr.infallible {
+        quote! { Ok(#fn_path(#call_args)) }
+    } else {
+        quote! { #fn_path(#call_args) }
+    };
+    match info.self_kind {
+        SelfKind::Ref(RefKind::Ref) => quote! {
+            registry.add_method(#lua_name, #closure_params { #body });
+        },
+        SelfKind::Ref(RefKind::Mut) => quote! {
+            registry.add_method_mut(#lua_name, #closure_params { #body });
+        },
+        SelfKind::Owned => quote! {
+            registry.add_method_once(#lua_name, #closure_params { #body });
+        },
+        SelfKind::None => quote! {
+            registry.add_function(#lua_name, #closure_params { #body });
+        },
+    }
+}
+
+fn gen_async_regular_method(
+    type_path: &syn::Path,
+    fn_name: &Ident,
+    lua_attr: &LuaAttr,
+    info: &MethodInfo,
+) -> TokenStream2 {
+    let fn_path = quote! { #type_path::#fn_name };
+    let closure_params = gen_async_closure_params(info);
+    let call_args = gen_async_call_args(info);
+    let lua_name = lua_attr.name(fn_name);
+
+    let body = if lua_attr.infallible {
+        quote! { async move { Ok(#fn_path(#call_args).await) } }
+    } else {
+        quote! { async move { #fn_path(#call_args).await } }
+    };
+    match info.self_kind {
+        SelfKind::Ref(RefKind::Ref) => quote! {
+            registry.add_async_method(#lua_name, #closure_params #body);
+        },
+        SelfKind::Ref(RefKind::Mut) => quote! {
+            registry.add_async_method_mut(#lua_name, #closure_params #body);
+        },
+        SelfKind::Owned => quote! {
+            registry.add_async_method_once(#lua_name, #closure_params #body);
+        },
+        SelfKind::None => quote! {
+            registry.add_async_function(#lua_name, #closure_params #body);
+        },
+    }
+}
+
+fn gen_async_meta(
+    type_path: &syn::Path,
+    fn_name: &Ident,
+    lua_attr: &LuaAttr,
+    info: &MethodInfo,
+) -> TokenStream2 {
+    let meta_name = match lua_attr.effective_meta_name(fn_name) {
+        Ok(name) => name,
+        Err(err) => return err.to_compile_error(),
+    };
+    let closure_params = if matches!(info.self_kind, SelfKind::None) {
+        if info.args.is_empty() {
+            quote! { |lua, _this: ::mlua::AnyUserData| }
+        } else {
+            let idents: Vec<_> = info.args.iter().map(|a| &a.ident).collect();
+            let types: Vec<_> = info.args.iter().map(|a| &a.callback_type).collect();
+            quote! { |lua, (_this, #(#idents),*): (::mlua::AnyUserData, #(#types),*) | }
+        }
+    } else {
+        gen_async_closure_params(info)
+    };
+    let call_args = gen_async_call_args(info);
+    let fn_path = quote! { #type_path::#fn_name };
+
+    let body = if lua_attr.infallible {
+        quote! { async move { Ok(#fn_path(#call_args).await) } }
+    } else {
+        quote! { async move { #fn_path(#call_args).await } }
+    };
+    match info.self_kind {
+        SelfKind::None => quote! {
+            registry.add_async_meta_function(#meta_name, #closure_params #body);
+        },
+        SelfKind::Ref(RefKind::Mut) => quote! {
+            registry.add_async_meta_method_mut(#meta_name, #closure_params #body);
+        },
+        _ => quote! {
+            registry.add_async_meta_method(#meta_name, #closure_params #body);
+        },
+    }
+}
@@ -59,7 +59,7 @@ impl Buffer {
    /// Returns an adaptor implementing [`io::Read`], [`io::Write`] and [`io::Seek`] over the
    /// buffer.
    ///
-    /// Buffer operations are infallible, none of the read/write functions will return a Err.
+    /// Buffer operations are infallible, none of the read/write functions will return an Err.
    pub fn cursor(self) -> impl io::Read + io::Write + io::Seek {
        BufferCursor(self, 0)
    }
@@ -97,7 +97,7 @@ struct BufferCursor(Buffer, usize);

 impl io::Read for BufferCursor {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let lua = self.0 .0.lua.lock();
+        let lua = self.0.0.lua.lock();
        let data = self.0.as_slice(&lua);
        if self.1 == data.len() {
            return Ok(0);
@@ -111,7 +111,7 @@ impl io::Read for BufferCursor {

 impl io::Write for BufferCursor {
    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        let lua = self.0 .0.lua.lock();
+        let lua = self.0.0.lua.lock();
        let data = self.0.as_slice_mut(&lua);
        if self.1 == data.len() {
            return Ok(0);
@@ -129,7 +129,7 @@ impl io::Write for BufferCursor {

 impl io::Seek for BufferCursor {
    fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
-        let lua = self.0 .0.lua.lock();
+        let lua = self.0.0.lua.lock();
        let data = self.0.as_slice(&lua);
        let new_offset = match pos {
            io::SeekFrom::Start(offset) => offset as i64,
@@ -1,10 +1,16 @@
+//! Lua chunk loading and execution.
+//!
+//! This module provides types for loading Lua source code or bytecode into a [`Chunk`],
+//! configuring how it is compiled and executed, and converting it into a callable [`Function`].
+//!
+//! Chunks can be loaded from strings, byte slices, or files via the [`AsChunk`] trait.
+
 use std::borrow::Cow;
 use std::collections::HashMap;
 use std::ffi::CString;
 use std::io::Result as IoResult;
 use std::panic::Location;
 use std::path::{Path, PathBuf};
-use std::string::String as StdString;

 use crate::error::{Error, Result};
 use crate::function::Function;
@@ -20,7 +26,7 @@ pub trait AsChunk {
    /// Returns optional chunk name
    ///
    /// See [`Chunk::set_name`] for possible name prefixes.
-    fn name(&self) -> Option<StdString> {
+    fn name(&self) -> Option<String> {
        None
    }

@@ -52,13 +58,13 @@ impl AsChunk for &str {
    }
 }

-impl AsChunk for StdString {
+impl AsChunk for String {
    fn source<'a>(&self) -> IoResult<Cow<'a, [u8]>> {
        Ok(Cow::Owned(self.clone().into_bytes()))
    }
 }

-impl AsChunk for &StdString {
+impl AsChunk for &String {
    fn source<'a>(&self) -> IoResult<Cow<'a, [u8]>>
    where
        Self: 'a,
@@ -92,7 +98,7 @@ impl AsChunk for &Vec<u8> {
 }

 impl AsChunk for &Path {
-    fn name(&self) -> Option<StdString> {
+    fn name(&self) -> Option<String> {
        Some(format!("@{}", self.display()))
    }

@@ -102,7 +108,7 @@ impl AsChunk for &Path {
 }

 impl AsChunk for PathBuf {
-    fn name(&self) -> Option<StdString> {
+    fn name(&self) -> Option<String> {
        Some(format!("@{}", self.display()))
    }

@@ -112,7 +118,7 @@ impl AsChunk for PathBuf {
 }

 impl<C: AsChunk + ?Sized> AsChunk for Box<C> {
-    fn name(&self) -> Option<StdString> {
+    fn name(&self) -> Option<String> {
        (**self).name()
    }

@@ -136,7 +142,7 @@ impl<C: AsChunk + ?Sized> AsChunk for Box<C> {
 #[must_use = "`Chunk`s do nothing unless one of `exec`, `eval`, `call`, or `into_function` are called on them"]
 pub struct Chunk<'a> {
    pub(crate) lua: WeakLua,
-    pub(crate) name: StdString,
+    pub(crate) name: String,
    pub(crate) env: Result<Option<Table>>,
    pub(crate) mode: Option<ChunkMode>,
    pub(crate) source: IoResult<Cow<'a, [u8]>>,
@@ -154,13 +160,14 @@ pub enum ChunkMode {
 /// Represents a constant value that can be used by Luau compiler.
 #[cfg(any(feature = "luau", doc))]
 #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
+#[non_exhaustive]
 #[derive(Clone, Debug)]
 pub enum CompileConstant {
    Nil,
    Boolean(bool),
    Number(crate::Number),
    Vector(crate::Vector),
-    String(StdString),
+    String(String),
 }

 #[cfg(any(feature = "luau", doc))]
@@ -192,7 +199,7 @@ impl From<&str> for CompileConstant {
 }

 #[cfg(any(feature = "luau", doc))]
-type LibraryMemberConstantMap = HashMap<(StdString, StdString), CompileConstant>;
+type LibraryMemberConstantMap = HashMap<(String, String), CompileConstant>;

 /// Luau compiler
 #[cfg(any(feature = "luau", doc))]
@@ -203,14 +210,14 @@ pub struct Compiler {
    debug_level: u8,
    type_info_level: u8,
    coverage_level: u8,
-    vector_lib: Option<StdString>,
-    vector_ctor: Option<StdString>,
-    vector_type: Option<StdString>,
-    mutable_globals: Vec<StdString>,
-    userdata_types: Vec<StdString>,
-    libraries_with_known_members: Vec<StdString>,
+    vector_lib: Option<String>,
+    vector_ctor: Option<String>,
+    vector_type: Option<String>,
+    mutable_globals: Vec<String>,
+    userdata_types: Vec<String>,
+    libraries_with_known_members: Vec<String>,
    library_constants: Option<LibraryMemberConstantMap>,
-    disabled_builtins: Vec<StdString>,
+    disabled_builtins: Vec<String>,
 }

 #[cfg(any(feature = "luau", doc))]
@@ -294,7 +301,7 @@ impl Compiler {
    /// To set the library and method name, use the `lib.ctor` format.
    #[doc(hidden)]
    #[must_use]
-    pub fn set_vector_ctor(mut self, ctor: impl Into<StdString>) -> Self {
+    pub fn set_vector_ctor(mut self, ctor: impl Into<String>) -> Self {
        let ctor = ctor.into();
        let lib_ctor = ctor.split_once('.');
        self.vector_lib = lib_ctor.as_ref().map(|&(lib, _)| lib.to_owned());
@@ -307,7 +314,7 @@ impl Compiler {
    /// Sets alternative vector type name for type tables, in addition to default type `vector`.
    #[doc(hidden)]
    #[must_use]
-    pub fn set_vector_type(mut self, r#type: impl Into<StdString>) -> Self {
+    pub fn set_vector_type(mut self, r#type: impl Into<String>) -> Self {
        self.vector_type = Some(r#type.into());
        self
    }
@@ -316,7 +323,7 @@ impl Compiler {
    ///
    /// It disables the import optimization for fields accessed through it.
    #[must_use]
-    pub fn add_mutable_global(mut self, global: impl Into<StdString>) -> Self {
+    pub fn add_mutable_global(mut self, global: impl Into<String>) -> Self {
        self.mutable_globals.push(global.into());
        self
    }
@@ -325,21 +332,21 @@ impl Compiler {
    ///
    /// It disables the import optimization for fields accessed through these.
    #[must_use]
-    pub fn set_mutable_globals<S: Into<StdString>>(mut self, globals: impl IntoIterator<Item = S>) -> Self {
+    pub fn set_mutable_globals<S: Into<String>>(mut self, globals: impl IntoIterator<Item = S>) -> Self {
        self.mutable_globals = globals.into_iter().map(|s| s.into()).collect();
        self
    }

    /// Adds a userdata type to the list that will be included in the type information.
    #[must_use]
-    pub fn add_userdata_type(mut self, r#type: impl Into<StdString>) -> Self {
+    pub fn add_userdata_type(mut self, r#type: impl Into<String>) -> Self {
        self.userdata_types.push(r#type.into());
        self
    }

    /// Sets a list of userdata types that will be included in the type information.
    #[must_use]
-    pub fn set_userdata_types<S: Into<StdString>>(mut self, types: impl IntoIterator<Item = S>) -> Self {
+    pub fn set_userdata_types<S: Into<String>>(mut self, types: impl IntoIterator<Item = S>) -> Self {
        self.userdata_types = types.into_iter().map(|s| s.into()).collect();
        self
    }
@@ -366,24 +373,21 @@ impl Compiler {
            self.libraries_with_known_members.push(lib.clone());
        }
        self.library_constants
-            .get_or_insert_with(HashMap::new)
+            .get_or_insert_default()
            .insert((lib, member), r#const.into());
        self
    }

    /// Adds a builtin that should be disabled.
    #[must_use]
-    pub fn add_disabled_builtin(mut self, builtin: impl Into<StdString>) -> Self {
+    pub fn add_disabled_builtin(mut self, builtin: impl Into<String>) -> Self {
        self.disabled_builtins.push(builtin.into());
        self
    }

    /// Sets a list of builtins that should be disabled.
    #[must_use]
-    pub fn set_disabled_builtins<S: Into<StdString>>(
-        mut self,
-        builtins: impl IntoIterator<Item = S>,
-    ) -> Self {
+    pub fn set_disabled_builtins<S: Into<String>>(mut self, builtins: impl IntoIterator<Item = S>) -> Self {
        self.disabled_builtins = builtins.into_iter().map(|s| s.into()).collect();
        self
    }
@@ -477,11 +481,11 @@ impl Compiler {
            options.mutableGlobals = mutable_globals_ptr;
            options.userdataTypes = userdata_types_ptr;
            options.librariesWithKnownMembers = libraries_with_known_members_ptr;
-            if let Some(map) = self.library_constants.as_ref() {
-                if !self.libraries_with_known_members.is_empty() {
-                    LIBRARY_MEMBER_CONSTANT_MAP.with_borrow_mut(|gmap| *gmap = map.clone());
-                    options.libraryMemberConstantCallback = Some(library_member_constant_callback);
-                }
+            if let Some(map) = self.library_constants.as_ref()
+                && !self.libraries_with_known_members.is_empty()
+            {
+                LIBRARY_MEMBER_CONSTANT_MAP.with_borrow_mut(|gmap| *gmap = map.clone());
+                options.libraryMemberConstantCallback = Some(library_member_constant_callback);
            }
            options.disabledBuiltins = disabled_builtins_ptr;
            ffi::luau_compile(source.as_ref(), options)
@@ -490,7 +494,7 @@ impl Compiler {
        if bytecode.first() == Some(&0) {
            // The rest of the bytecode is the error message starting with `:`
            // See https://github.com/luau-lang/luau/blob/0.640/Compiler/src/Compiler.cpp#L4336
-            let message = StdString::from_utf8_lossy(&bytecode[2..]).into_owned();
+            let message = String::from_utf8_lossy(&bytecode[2..]).into_owned();
            return Err(Error::SyntaxError {
                incomplete_input: message.ends_with("<eof>"),
                message,
@@ -513,7 +517,7 @@ impl Chunk<'_> {
    /// - `@` - file path (when truncation is needed, the end of the file path is kept, as this is
    ///   more useful for identifying the file)
    /// - `=` - custom chunk name (when truncation is needed, the beginning of the name is kept)
-    pub fn set_name(mut self, name: impl Into<StdString>) -> Self {
+    pub fn set_name(mut self, name: impl Into<String>) -> Self {
        self.name = name.into();
        self
    }
@@ -662,19 +666,19 @@ impl Chunk<'_> {
    ///
    /// It does nothing if the chunk is already binary or invalid.
    fn compile(&mut self) {
-        if let Ok(ref source) = self.source {
-            if self.detect_mode() == ChunkMode::Text {
-                #[cfg(feature = "luau")]
-                if let Ok(data) = self.compiler.get_or_insert_with(Default::default).compile(source) {
-                    self.source = Ok(Cow::Owned(data));
-                    self.mode = Some(ChunkMode::Binary);
-                }
-                #[cfg(not(feature = "luau"))]
-                if let Ok(func) = self.lua.lock().load_chunk(None, None, None, source.as_ref()) {
-                    let data = func.dump(false);
-                    self.source = Ok(Cow::Owned(data));
-                    self.mode = Some(ChunkMode::Binary);
-                }
+        if let Ok(ref source) = self.source
+            && self.detect_mode() == ChunkMode::Text
+        {
+            #[cfg(feature = "luau")]
+            if let Ok(data) = self.compiler.get_or_insert_default().compile(source) {
+                self.source = Ok(Cow::Owned(data));
+                self.mode = Some(ChunkMode::Binary);
+            }
+            #[cfg(not(feature = "luau"))]
+            if let Ok(func) = self.lua.lock().load_chunk(None, None, None, source.as_ref()) {
+                let data = func.dump(false);
+                self.source = Ok(Cow::Owned(data));
+                self.mode = Some(ChunkMode::Binary);
            }
        }
    }
@@ -687,33 +691,33 @@ impl Chunk<'_> {

        // Try to fetch compiled chunk from cache
        let mut text_source = None;
-        if let Ok(ref source) = self.source {
-            if self.detect_mode() == ChunkMode::Text {
-                let lua = self.lua.lock();
-                if let Some(cache) = lua.priv_app_data_ref::<ChunksCache>() {
-                    if let Some(data) = cache.0.get(source.as_ref()) {
-                        self.source = Ok(Cow::Owned(data.clone()));
-                        self.mode = Some(ChunkMode::Binary);
-                        return self;
-                    }
-                }
-                text_source = Some(source.as_ref().to_vec());
+        if let Ok(ref source) = self.source
+            && self.detect_mode() == ChunkMode::Text
+        {
+            let lua = self.lua.lock();
+            if let Some(cache) = lua.priv_app_data_ref::<ChunksCache>()
+                && let Some(data) = cache.0.get(source.as_ref())
+            {
+                self.source = Ok(Cow::Owned(data.clone()));
+                self.mode = Some(ChunkMode::Binary);
+                return self;
            }
+            text_source = Some(source.as_ref().to_vec());
        }

        // Compile and cache the chunk
        if let Some(text_source) = text_source {
            self.compile();
-            if let Ok(ref binary_source) = self.source {
-                if self.detect_mode() == ChunkMode::Binary {
-                    let lua = self.lua.lock();
-                    if let Some(mut cache) = lua.priv_app_data_mut::<ChunksCache>() {
-                        cache.0.insert(text_source, binary_source.to_vec());
-                    } else {
-                        let mut cache = ChunksCache(HashMap::new());
-                        cache.0.insert(text_source, binary_source.to_vec());
-                        lua.set_priv_app_data(cache);
-                    };
+            if let Ok(ref binary_source) = self.source
+                && self.detect_mode() == ChunkMode::Binary
+            {
+                let lua = self.lua.lock();
+                if let Some(mut cache) = lua.priv_app_data_mut::<ChunksCache>() {
+                    cache.0.insert(text_source, binary_source.to_vec());
+                } else {
+                    let mut cache = ChunksCache(HashMap::new());
+                    cache.0.insert(text_source, binary_source.to_vec());
+                    lua.set_priv_app_data(cache);
                }
            }
        }
@@ -761,7 +765,7 @@ impl Chunk<'_> {
        ChunkMode::Text
    }

-    fn convert_name(name: StdString) -> Result<CString> {
+    fn convert_name(name: String) -> Result<CString> {
        CString::new(name).map_err(|err| Error::runtime(format!("invalid name: {err}")))
    }

@@ -783,7 +787,6 @@ impl Chunk<'_> {
    ///
    /// The resulted `IntoLua` implementation will convert the chunk into a Lua function without
    /// executing it.
-    #[doc(hidden)]
    #[track_caller]
    pub fn wrap(chunk: impl AsChunk) -> impl IntoLua {
        WrappedChunk {
@@ -4,20 +4,19 @@ use std::ffi::{CStr, CString, OsStr, OsString};
 use std::hash::{BuildHasher, Hash};
 use std::os::raw::c_int;
 use std::path::{Path, PathBuf};
-use std::string::String as StdString;
-use std::{mem, slice, str};
+use std::{slice, str};

-use bstr::{BStr, BString, ByteSlice, ByteVec};
+use bstr::{BStr, BString, ByteVec};
 use num_traits::cast;

 use crate::error::{Error, Result};
 use crate::function::Function;
 use crate::state::{Lua, RawLua};
-use crate::string::{BorrowedBytes, BorrowedStr, String};
+use crate::string::{BorrowedBytes, BorrowedStr, LuaString};
 use crate::table::Table;
 use crate::thread::Thread;
 use crate::traits::{FromLua, IntoLua, ShortTypeName as _};
-use crate::types::{Either, LightUserData, MaybeSend, RegistryKey};
+use crate::types::{Either, LightUserData, MaybeSend, MaybeSync, RegistryKey};
 use crate::userdata::{AnyUserData, UserData};
 use crate::value::{Nil, Value};

@@ -47,14 +46,14 @@ impl FromLua for Value {
    }
 }

-impl IntoLua for String {
+impl IntoLua for LuaString {
    #[inline]
    fn into_lua(self, _: &Lua) -> Result<Value> {
        Ok(Value::String(self))
    }
 }

-impl IntoLua for &String {
+impl IntoLua for &LuaString {
    #[inline]
    fn into_lua(self, _: &Lua) -> Result<Value> {
        Ok(Value::String(self.clone()))
@@ -67,16 +66,12 @@ impl IntoLua for &String {
    }
 }

-impl FromLua for String {
+impl FromLua for LuaString {
    #[inline]
-    fn from_lua(value: Value, lua: &Lua) -> Result<String> {
+    fn from_lua(value: Value, lua: &Lua) -> Result<LuaString> {
        let ty = value.type_name();
        lua.coerce_string(value)?
-            .ok_or_else(|| Error::FromLuaConversionError {
-                from: ty,
-                to: "string".to_string(),
-                message: Some("expected string or number".to_string()),
-            })
+            .ok_or_else(|| Error::from_lua_conversion(ty, "string", "expected string or number".to_string()))
    }

    unsafe fn from_stack(idx: c_int, lua: &RawLua) -> Result<Self> {
@@ -84,98 +79,86 @@ impl FromLua for String {
        let type_id = ffi::lua_type(state, idx);
        if type_id == ffi::LUA_TSTRING {
            ffi::lua_xpush(state, lua.ref_thread(), idx);
-            return Ok(String(lua.pop_ref_thread()));
+            return Ok(LuaString(lua.pop_ref_thread()));
        }
        // Fallback to default
        Self::from_lua(lua.stack_value(idx, Some(type_id)), lua.lua())
    }
 }

-impl IntoLua for BorrowedStr<'_> {
+impl IntoLua for BorrowedStr {
    #[inline]
    fn into_lua(self, _: &Lua) -> Result<Value> {
-        Ok(Value::String(self.borrow.into_owned()))
+        Ok(Value::String(LuaString(self.vref)))
    }

    #[inline]
    unsafe fn push_into_stack(self, lua: &RawLua) -> Result<()> {
-        lua.push_ref(&self.borrow.0);
+        lua.push_ref(&self.vref);
        Ok(())
    }
 }

-impl IntoLua for &BorrowedStr<'_> {
+impl IntoLua for &BorrowedStr {
    #[inline]
    fn into_lua(self, _: &Lua) -> Result<Value> {
-        Ok(Value::String(self.borrow.clone().into_owned()))
+        Ok(Value::String(LuaString(self.vref.clone())))
    }

    #[inline]
    unsafe fn push_into_stack(self, lua: &RawLua) -> Result<()> {
-        lua.push_ref(&self.borrow.0);
+        lua.push_ref(&self.vref);
        Ok(())
    }
 }

-impl FromLua for BorrowedStr<'_> {
+impl FromLua for BorrowedStr {
    fn from_lua(value: Value, lua: &Lua) -> Result<Self> {
-        let s = String::from_lua(value, lua)?;
-        let BorrowedStr { buf, _lua, .. } = BorrowedStr::try_from(&s)?;
-        let buf = unsafe { mem::transmute::<&str, &'static str>(buf) };
-        let borrow = Cow::Owned(s);
-        Ok(Self { buf, borrow, _lua })
+        let s = LuaString::from_lua(value, lua)?;
+        BorrowedStr::try_from(&s)
    }

    unsafe fn from_stack(idx: c_int, lua: &RawLua) -> Result<Self> {
-        let s = String::from_stack(idx, lua)?;
-        let BorrowedStr { buf, _lua, .. } = BorrowedStr::try_from(&s)?;
-        let buf = unsafe { mem::transmute::<&str, &'static str>(buf) };
-        let borrow = Cow::Owned(s);
-        Ok(Self { buf, borrow, _lua })
+        let s = LuaString::from_stack(idx, lua)?;
+        BorrowedStr::try_from(&s)
    }
 }

-impl IntoLua for BorrowedBytes<'_> {
+impl IntoLua for BorrowedBytes {
    #[inline]
    fn into_lua(self, _: &Lua) -> Result<Value> {
-        Ok(Value::String(self.borrow.into_owned()))
+        Ok(Value::String(LuaString(self.vref)))
    }

    #[inline]
    unsafe fn push_into_stack(self, lua: &RawLua) -> Result<()> {
-        lua.push_ref(&self.borrow.0);
+        lua.push_ref(&self.vref);
        Ok(())
    }
 }

-impl IntoLua for &BorrowedBytes<'_> {
+impl IntoLua for &BorrowedBytes {
    #[inline]
    fn into_lua(self, _: &Lua) -> Result<Value> {
-        Ok(Value::String(self.borrow.clone().into_owned()))
+        Ok(Value::String(LuaString(self.vref.clone())))
    }

    #[inline]
    unsafe fn push_into_stack(self, lua: &RawLua) -> Result<()> {
-        lua.push_ref(&self.borrow.0);
+        lua.push_ref(&self.vref);
        Ok(())
    }
 }

-impl FromLua for BorrowedBytes<'_> {
+impl FromLua for BorrowedBytes {
    fn from_lua(value: Value, lua: &Lua) -> Result<Self> {
-        let s = String::from_lua(value, lua)?;
-        let BorrowedBytes { buf, _lua, .. } = BorrowedBytes::from(&s);
-        let buf = unsafe { mem::transmute::<&[u8], &'static [u8]>(buf) };
-        let borrow = Cow::Owned(s);
-        Ok(Self { buf, borrow, _lua })
+        let s = LuaString::from_lua(value, lua)?;
+        Ok(BorrowedBytes::from(&s))
    }

    unsafe fn from_stack(idx: c_int, lua: &RawLua) -> Result<Self> {
-        let s = String::from_stack(idx, lua)?;
-        let BorrowedBytes { buf, _lua, .. } = BorrowedBytes::from(&s);
-        let buf = unsafe { mem::transmute::<&[u8], &'static [u8]>(buf) };
-        let borrow = Cow::Owned(s);
-        Ok(Self { buf, borrow, _lua })
+        let s = LuaString::from_stack(idx, lua)?;
+        Ok(BorrowedBytes::from(&s))
    }
 }

@@ -204,11 +187,7 @@ impl FromLua for Table {
    fn from_lua(value: Value, _: &Lua) -> Result<Table> {
        match value {
            Value::Table(table) => Ok(table),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "table".to_string(),
-                message: None,
-            }),
+            _ => Err(Error::from_lua_conversion(value.type_name(), "table", None)),
        }
    }
 }
@@ -238,11 +217,7 @@ impl FromLua for Function {
    fn from_lua(value: Value, _: &Lua) -> Result<Function> {
        match value {
            Value::Function(table) => Ok(table),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "function".to_string(),
-                message: None,
-            }),
+            _ => Err(Error::from_lua_conversion(value.type_name(), "function", None)),
        }
    }
 }
@@ -272,11 +247,7 @@ impl FromLua for Thread {
    fn from_lua(value: Value, _: &Lua) -> Result<Thread> {
        match value {
            Value::Thread(t) => Ok(t),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "thread".to_string(),
-                message: None,
-            }),
+            _ => Err(Error::from_lua_conversion(value.type_name(), "thread", None)),
        }
    }
 }
@@ -306,16 +277,12 @@ impl FromLua for AnyUserData {
    fn from_lua(value: Value, _: &Lua) -> Result<AnyUserData> {
        match value {
            Value::UserData(ud) => Ok(ud),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "userdata".to_string(),
-                message: None,
-            }),
+            _ => Err(Error::from_lua_conversion(value.type_name(), "userdata", None)),
        }
    }
 }

-impl<T: UserData + MaybeSend + 'static> IntoLua for T {
+impl<T: UserData + MaybeSend + MaybeSync + 'static> IntoLua for T {
    #[inline]
    fn into_lua(self, lua: &Lua) -> Result<Value> {
        Ok(Value::UserData(lua.create_userdata(self)?))
@@ -428,11 +395,11 @@ impl FromLua for LightUserData {
    fn from_lua(value: Value, _: &Lua) -> Result<Self> {
        match value {
            Value::LightUserData(ud) => Ok(ud),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "lightuserdata".to_string(),
-                message: None,
-            }),
+            _ => Err(Error::from_lua_conversion(
+                value.type_name(),
+                "lightuserdata",
+                None,
+            )),
        }
    }
 }
@@ -451,11 +418,7 @@ impl FromLua for crate::Vector {
    fn from_lua(value: Value, _: &Lua) -> Result<Self> {
        match value {
            Value::Vector(v) => Ok(v),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "vector".to_string(),
-                message: None,
-            }),
+            _ => Err(Error::from_lua_conversion(value.type_name(), "vector", None)),
        }
    }
 }
@@ -488,37 +451,41 @@ impl FromLua for crate::Buffer {
    fn from_lua(value: Value, _: &Lua) -> Result<Self> {
        match value {
            Value::Buffer(buf) => Ok(buf),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: "buffer".to_string(),
-                message: None,
-            }),
+            _ => Err(Error::from_lua_conversion(value.type_name(), "buffer", None)),
        }
    }
 }

-impl IntoLua for StdString {
+impl IntoLua for String {
    #[inline]
    fn into_lua(self, lua: &Lua) -> Result<Value> {
+        #[cfg(feature = "lua55")]
+        if true {
+            return Ok(Value::String(lua.create_external_string(self)?));
+        }
+
        Ok(Value::String(lua.create_string(self)?))
    }

    #[inline]
    unsafe fn push_into_stack(self, lua: &RawLua) -> Result<()> {
+        #[cfg(feature = "lua55")]
+        if lua.unlikely_memory_error() {
+            return crate::util::push_external_string(lua.state(), self.into(), false);
+        }
+
        push_bytes_into_stack(self, lua)
    }
 }

-impl FromLua for StdString {
+impl FromLua for String {
    #[inline]
    fn from_lua(value: Value, lua: &Lua) -> Result<Self> {
        let ty = value.type_name();
        Ok(lua
            .coerce_string(value)?
-            .ok_or_else(|| Error::FromLuaConversionError {
-                from: ty,
-                to: Self::type_name(),
-                message: Some("expected string or number".to_string()),
+            .ok_or_else(|| {
+                Error::from_lua_conversion(ty, Self::type_name(), "expected string or number".to_string())
            })?
            .to_str()?
            .to_owned())
@@ -534,11 +501,7 @@ impl FromLua for StdString {
            let bytes = slice::from_raw_parts(data as *const u8, size);
            return str::from_utf8(bytes)
                .map(|s| s.to_owned())
-                .map_err(|e| Error::FromLuaConversionError {
-                    from: "string",
-                    to: Self::type_name(),
-                    message: Some(e.to_string()),
-                });
+                .map_err(|e| Error::from_lua_conversion("string", Self::type_name(), e.to_string()));
        }
        // Fallback to default
        Self::from_lua(lua.stack_value(idx, Some(type_id)), lua.lua())
@@ -560,7 +523,10 @@ impl IntoLua for &str {
 impl IntoLua for Cow<'_, str> {
    #[inline]
    fn into_lua(self, lua: &Lua) -> Result<Value> {
-        Ok(Value::String(lua.create_string(self.as_bytes())?))
+        match self {
+            Cow::Borrowed(s) => s.into_lua(lua),
+            Cow::Owned(s) => s.into_lua(lua),
+        }
    }
 }

@@ -577,10 +543,8 @@ impl FromLua for Box<str> {
        let ty = value.type_name();
        Ok(lua
            .coerce_string(value)?
-            .ok_or_else(|| Error::FromLuaConversionError {
-                from: ty,
-                to: Self::type_name(),
-                message: Some("expected string or number".to_string()),
+            .ok_or_else(|| {
+                Error::from_lua_conversion(ty, Self::type_name(), "expected string or number".to_string())
            })?
            .to_str()?
            .to_owned()
@@ -591,6 +555,11 @@ impl FromLua for Box<str> {
 impl IntoLua for CString {
    #[inline]
    fn into_lua(self, lua: &Lua) -> Result<Value> {
+        #[cfg(feature = "lua55")]
+        if true {
+            return Ok(Value::String(lua.create_external_string(self)?));
+        }
+
        Ok(Value::String(lua.create_string(self.as_bytes())?))
    }
 }
@@ -599,21 +568,12 @@ impl FromLua for CString {
    #[inline]
    fn from_lua(value: Value, lua: &Lua) -> Result<Self> {
        let ty = value.type_name();
-        let string = lua
-            .coerce_string(value)?
-            .ok_or_else(|| Error::FromLuaConversionError {
-                from: ty,
-                to: Self::type_name(),
-                message: Some("expected string or number".to_string()),
-            })?;
-
+        let string = lua.coerce_string(value)?.ok_or_else(|| {
+            Error::from_lua_conversion(ty, Self::type_name(), "expected string or number".to_string())
+        })?;
        match CStr::from_bytes_with_nul(&string.as_bytes_with_nul()) {
            Ok(s) => Ok(s.into()),
-            Err(_) => Err(Error::FromLuaConversionError {
-                from: ty,
-                to: Self::type_name(),
-                message: Some("invalid C-style string".to_string()),
-            }),
+            Err(err) => Err(Error::from_lua_conversion(ty, Self::type_name(), err.to_string())),
        }
    }
 }
@@ -628,13 +588,21 @@ impl IntoLua for &CStr {
 impl IntoLua for Cow<'_, CStr> {
    #[inline]
    fn into_lua(self, lua: &Lua) -> Result<Value> {
-        Ok(Value::String(lua.create_string(self.to_bytes())?))
+        match self {
+            Cow::Borrowed(s) => s.into_lua(lua),
+            Cow::Owned(s) => s.into_lua(lua),
+        }
    }
 }

 impl IntoLua for BString {
    #[inline]
    fn into_lua(self, lua: &Lua) -> Result<Value> {
+        #[cfg(feature = "lua55")]
+        if true {
+            return Ok(Value::String(lua.create_external_string(self)?));
+        }
+
        Ok(Value::String(lua.create_string(self)?))
    }
 }
@@ -648,10 +616,8 @@ impl FromLua for BString {
            Value::Buffer(buf) => Ok(buf.to_vec().into()),
            _ => Ok((*lua
                .coerce_string(value)?
-                .ok_or_else(|| Error::FromLuaConversionError {
-                    from: ty,
-                    to: Self::type_name(),
-                    message: Some("expected string or number".to_string()),
+                .ok_or_else(|| {
+                    Error::from_lua_conversion(ty, Self::type_name(), "expected string or number".to_string())
                })?
                .as_bytes())
            .into()),
@@ -702,23 +668,22 @@ impl FromLua for OsString {
        let bs = BString::from_lua(value, lua)?;
        Vec::from(bs)
            .into_os_string()
-            .map_err(|err| Error::FromLuaConversionError {
-                from: ty,
-                to: "OsString".into(),
-                message: Some(err.to_string()),
-            })
+            .map_err(|err| Error::from_lua_conversion(ty, "OsString", err.to_string()))
    }
 }

 impl IntoLua for &OsStr {
+    #[cfg(unix)]
    #[inline]
    fn into_lua(self, lua: &Lua) -> Result<Value> {
-        let s = <[u8]>::from_os_str(self).ok_or_else(|| Error::ToLuaConversionError {
-            from: "OsStr".into(),
-            to: "string",
-            message: Some("invalid utf-8 encoding".into()),
-        })?;
-        Ok(Value::String(lua.create_string(s)?))
+        use std::os::unix::ffi::OsStrExt;
+        Ok(Value::String(lua.create_string(self.as_bytes())?))
+    }
+
+    #[cfg(not(unix))]
+    #[inline]
+    fn into_lua(self, lua: &Lua) -> Result<Value> {
+        self.display().to_string().into_lua(lua)
    }
 }

@@ -756,34 +721,25 @@ impl FromLua for char {
    fn from_lua(value: Value, _lua: &Lua) -> Result<Self> {
        let ty = value.type_name();
        match value {
-            Value::Integer(i) => {
-                cast(i)
-                    .and_then(char::from_u32)
-                    .ok_or_else(|| Error::FromLuaConversionError {
-                        from: ty,
-                        to: "char".to_string(),
-                        message: Some("integer out of range when converting to char".to_string()),
-                    })
-            }
+            Value::Integer(i) => cast(i).and_then(char::from_u32).ok_or_else(|| {
+                let msg = "integer out of range when converting to char";
+                Error::from_lua_conversion(ty, "char", msg.to_string())
+            }),
            Value::String(s) => {
                let str = s.to_str()?;
                let mut str_iter = str.chars();
                match (str_iter.next(), str_iter.next()) {
                    (Some(char), None) => Ok(char),
-                    _ => Err(Error::FromLuaConversionError {
-                        from: ty,
-                        to: "char".to_string(),
-                        message: Some(
-                            "expected string to have exactly one char when converting to char".to_string(),
-                        ),
-                    }),
+                    _ => {
+                        let msg = "expected string to have exactly one char when converting to char";
+                        Err(Error::from_lua_conversion(ty, "char", msg.to_string()))
+                    }
                }
            }
-            _ => Err(Error::FromLuaConversionError {
-                from: ty,
-                to: Self::type_name(),
-                message: Some("expected string or integer".to_string()),
-            }),
+            _ => {
+                let msg = "expected string or integer";
+                Err(Error::from_lua_conversion(ty, Self::type_name(), msg.to_string()))
+            }
        }
    }
 }
@@ -834,24 +790,14 @@ macro_rules! lua_convert_int {
                        if let Some(i) = lua.coerce_integer(value.clone())? {
                            cast(i)
                        } else {
-                            cast(
-                                lua.coerce_number(value)?
-                                    .ok_or_else(|| Error::FromLuaConversionError {
-                                        from: ty,
-                                        to: stringify!($x).to_string(),
-                                        message: Some(
-                                            "expected number or string coercible to number".to_string(),
-                                        ),
-                                    })?,
-                            )
+                            cast(lua.coerce_number(value)?.ok_or_else(|| {
+                                let msg = "expected number or string coercible to number";
+                                Error::from_lua_conversion(ty, stringify!($x), msg.to_string())
+                            })?)
                        }
                    }
                })
-                .ok_or_else(|| Error::FromLuaConversionError {
-                    from: ty,
-                    to: stringify!($x).to_string(),
-                    message: Some("out of range".to_owned()),
-                })
+                .ok_or_else(|| Error::from_lua_conversion(ty, stringify!($x), "out of range".to_string()))
            }

            unsafe fn from_stack(idx: c_int, lua: &RawLua) -> Result<Self> {
@@ -861,13 +807,18 @@ macro_rules! lua_convert_int {
                    let mut ok = 0;
                    let i = ffi::lua_tointegerx(state, idx, &mut ok);
                    if ok != 0 {
-                        return cast(i).ok_or_else(|| Error::FromLuaConversionError {
-                            from: "integer",
-                            to: stringify!($x).to_string(),
-                            message: Some("out of range".to_owned()),
+                        return cast(i).ok_or_else(|| {
+                            Error::from_lua_conversion("integer", stringify!($x), "out of range".to_string())
                        });
                    }
                }
+                #[cfg(feature = "luau")]
+                if type_id == ffi::LUA_TINTEGER {
+                    let i = ffi::lua_tointeger64(state, idx, std::ptr::null_mut());
+                    return cast(i).ok_or_else(|| {
+                        Error::from_lua_conversion("integer", stringify!($x), "out of range".to_string())
+                    });
+                }
                // Fallback to default
                Self::from_lua(lua.stack_value(idx, Some(type_id)), lua.lua())
            }
@@ -901,13 +852,10 @@ macro_rules! lua_convert_float {
            #[inline]
            fn from_lua(value: Value, lua: &Lua) -> Result<Self> {
                let ty = value.type_name();
-                lua.coerce_number(value)?
-                    .map(|n| n as $x)
-                    .ok_or_else(|| Error::FromLuaConversionError {
-                        from: ty,
-                        to: stringify!($x).to_string(),
-                        message: Some("expected number or string coercible to number".to_string()),
-                    })
+                lua.coerce_number(value)?.map(|n| n as $x).ok_or_else(|| {
+                    let msg = "expected number or string coercible to number";
+                    Error::from_lua_conversion(ty, stringify!($x), msg.to_string())
+                })
            }

            unsafe fn from_stack(idx: c_int, lua: &RawLua) -> Result<Self> {
@@ -967,18 +915,16 @@ where
            },
            Value::Table(table) => {
                let vec = table.sequence_values().collect::<Result<Vec<_>>>()?;
-                vec.try_into()
-                    .map_err(|vec: Vec<T>| Error::FromLuaConversionError {
-                        from: "table",
-                        to: Self::type_name(),
-                        message: Some(format!("expected table of length {N}, got {}", vec.len())),
-                    })
+                vec.try_into().map_err(|vec: Vec<T>| {
+                    let msg = format!("expected table of length {N}, got {}", vec.len());
+                    Error::from_lua_conversion("table", Self::type_name(), msg)
+                })
+            }
+            _ => {
+                let msg = format!("expected table of length {N}");
+                let err = Error::from_lua_conversion(value.type_name(), Self::type_name(), msg.to_string());
+                Err(err)
            }
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: Self::type_name(),
-                message: Some("expected table".to_string()),
-            }),
        }
    }
 }
@@ -1009,11 +955,11 @@ impl<T: FromLua> FromLua for Vec<T> {
    fn from_lua(value: Value, _lua: &Lua) -> Result<Self> {
        match value {
            Value::Table(table) => table.sequence_values().collect(),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: Self::type_name(),
-                message: Some("expected table".to_string()),
-            }),
+            _ => Err(Error::from_lua_conversion(
+                value.type_name(),
+                Self::type_name(),
+                "expected table".to_string(),
+            )),
        }
    }
 }
@@ -1028,14 +974,13 @@ impl<K: Eq + Hash + IntoLua, V: IntoLua, S: BuildHasher> IntoLua for HashMap<K,
 impl<K: Eq + Hash + FromLua, V: FromLua, S: BuildHasher + Default> FromLua for HashMap<K, V, S> {
    #[inline]
    fn from_lua(value: Value, _: &Lua) -> Result<Self> {
-        if let Value::Table(table) = value {
-            table.pairs().collect()
-        } else {
-            Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: Self::type_name(),
-                message: Some("expected table".to_string()),
-            })
+        match value {
+            Value::Table(table) => table.pairs().collect(),
+            _ => Err(Error::from_lua_conversion(
+                value.type_name(),
+                Self::type_name(),
+                "expected table".to_string(),
+            )),
        }
    }
 }
@@ -1050,14 +995,13 @@ impl<K: Ord + IntoLua, V: IntoLua> IntoLua for BTreeMap<K, V> {
 impl<K: Ord + FromLua, V: FromLua> FromLua for BTreeMap<K, V> {
    #[inline]
    fn from_lua(value: Value, _: &Lua) -> Result<Self> {
-        if let Value::Table(table) = value {
-            table.pairs().collect()
-        } else {
-            Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: Self::type_name(),
-                message: Some("expected table".to_string()),
-            })
+        match value {
+            Value::Table(table) => table.pairs().collect(),
+            _ => Err(Error::from_lua_conversion(
+                value.type_name(),
+                Self::type_name(),
+                "expected table".to_string(),
+            )),
        }
    }
 }
@@ -1077,11 +1021,11 @@ impl<T: Eq + Hash + FromLua, S: BuildHasher + Default> FromLua for HashSet<T, S>
        match value {
            Value::Table(table) if table.raw_len() > 0 => table.sequence_values().collect(),
            Value::Table(table) => table.pairs::<T, Value>().map(|res| res.map(|(k, _)| k)).collect(),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: Self::type_name(),
-                message: Some("expected table".to_string()),
-            }),
+            _ => Err(Error::from_lua_conversion(
+                value.type_name(),
+                Self::type_name(),
+                "expected table".to_string(),
+            )),
        }
    }
 }
@@ -1101,11 +1045,11 @@ impl<T: Ord + FromLua> FromLua for BTreeSet<T> {
        match value {
            Value::Table(table) if table.raw_len() > 0 => table.sequence_values().collect(),
            Value::Table(table) => table.pairs::<T, Value>().map(|res| res.map(|(k, _)| k)).collect(),
-            _ => Err(Error::FromLuaConversionError {
-                from: value.type_name(),
-                to: Self::type_name(),
-                message: Some("expected table".to_string()),
-            }),
+            _ => Err(Error::from_lua_conversion(
+                value.type_name(),
+                Self::type_name(),
+                "expected table".to_string(),
+            )),
        }
    }
 }
@@ -1175,11 +1119,11 @@ impl<L: FromLua, R: FromLua> FromLua for Either<L, R> {
            // Try the right type
            Err(_) => match R::from_lua(value, lua).map(Either::Right) {
                Ok(r) => Ok(r),
-                Err(_) => Err(Error::FromLuaConversionError {
-                    from: value_type_name,
-                    to: Self::type_name(),
-                    message: None,
-                }),
+                Err(_) => Err(Error::from_lua_conversion(
+                    value_type_name,
+                    Self::type_name(),
+                    None,
+                )),
            },
        }
    }
@@ -1191,12 +1135,12 @@ impl<L: FromLua, R: FromLua> FromLua for Either<L, R> {
            Err(_) => match R::from_stack(idx, lua).map(Either::Right) {
                Ok(r) => Ok(r),
                Err(_) => {
-                    let value_type_name = CStr::from_ptr(ffi::luaL_typename(lua.state(), idx));
-                    Err(Error::FromLuaConversionError {
-                        from: value_type_name.to_str().unwrap(),
-                        to: Self::type_name(),
-                        message: None,
-                    })
+                    let state = lua.state();
+                    let from_type_name = CStr::from_ptr(ffi::lua_typename(state, ffi::lua_type(state, idx)))
+                        .to_str()
+                        .unwrap_or("unknown");
+                    let err = Error::from_lua_conversion(from_type_name, Self::type_name(), None);
+                    Err(err)
                }
            },
        }
@@ -1,3 +1,9 @@
+//! Lua debugging interface.
+//!
+//! This module provides access to the Lua debug interface, allowing inspection of the call stack,
+//! and function information. The main types are [`struct@Debug`] for accessing debug information
+//! and [`HookTriggers`] for configuring debug hooks.
+
 use std::borrow::Cow;
 use std::os::raw::c_int;

@@ -5,7 +11,7 @@ use ffi::{lua_Debug, lua_State};

 use crate::function::Function;
 use crate::state::RawLua;
-use crate::util::{assert_stack, linenumber_to_usize, ptr_to_lossy_str, ptr_to_str, StackGuard};
+use crate::util::{StackGuard, assert_stack, linenumber_to_usize, ptr_to_lossy_str, ptr_to_str};

 /// Contains information about currently executing Lua code.
 ///
@@ -133,12 +139,6 @@ impl<'a> Debug<'a> {
        }
    }

-    #[doc(hidden)]
-    #[deprecated(note = "Use `current_line` instead")]
-    pub fn curr_line(&self) -> i32 {
-        self.current_line().map(|n| n as i32).unwrap_or(-1)
-    }
-
    /// Corresponds to the `l` "what" mask. Returns the current line.
    pub fn current_line(&self) -> Option<usize> {
        unsafe {
@@ -159,10 +159,10 @@ impl<'a> Debug<'a> {

    /// Corresponds to the `t` "what" mask. Returns true if the hook is in a function tail call,
    /// false otherwise.
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
    #[cfg_attr(
        docsrs,
-        doc(cfg(any(feature = "lua54", feature = "lua53", feature = "lua52")))
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52")))
    )]
    pub fn is_tail_call(&self) -> bool {
        unsafe {
@@ -190,15 +190,15 @@ impl<'a> Debug<'a> {

            #[cfg(not(feature = "luau"))]
            let stack = DebugStack {
-                num_ups: (*self.ar).nups as _,
-                #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+                num_upvalues: (*self.ar).nups as _,
+                #[cfg(not(any(feature = "lua51", feature = "luajit")))]
                num_params: (*self.ar).nparams as _,
-                #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+                #[cfg(not(any(feature = "lua51", feature = "luajit")))]
                is_vararg: (*self.ar).isvararg != 0,
            };
            #[cfg(feature = "luau")]
            let stack = DebugStack {
-                num_ups: (*self.ar).nupvals,
+                num_upvalues: (*self.ar).nupvals,
                num_params: (*self.ar).nparams,
                is_vararg: (*self.ar).isvararg != 0,
            };
@@ -208,6 +208,8 @@ impl<'a> Debug<'a> {
 }

 /// Represents a specific event that triggered the hook.
+#[cfg(not(feature = "luau"))]
+#[cfg_attr(docsrs, doc(cfg(not(feature = "luau"))))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum DebugEvent {
    Call,
@@ -218,6 +220,9 @@ pub enum DebugEvent {
    Unknown(c_int),
 }

+/// Contains the name information of a function in the call stack.
+///
+/// Returned by the [`Debug::names`] method.
 #[derive(Clone, Debug)]
 pub struct DebugNames<'a> {
    /// A (reasonable) name of the function (`None` if the name cannot be found).
@@ -228,6 +233,9 @@ pub struct DebugNames<'a> {
    pub name_what: Option<&'static str>,
 }

+/// Contains the source information of a function in the call stack.
+///
+/// Returned by the [`Debug::source`] method.
 #[derive(Clone, Debug)]
 pub struct DebugSource<'a> {
    /// Source of the chunk that created the function.
@@ -243,23 +251,20 @@ pub struct DebugSource<'a> {
    pub what: &'static str,
 }

+/// Contains stack information about a function in the call stack.
+///
+/// Returned by the [`Debug::stack`] method.
 #[derive(Copy, Clone, Debug)]
 pub struct DebugStack {
-    /// Number of upvalues.
-    pub num_ups: u8,
-    /// Number of parameters.
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau"))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau")))
-    )]
+    /// The number of upvalues of the function.
+    pub num_upvalues: u8,
+    /// The number of parameters of the function (always 0 for C).
+    #[cfg(any(not(any(feature = "lua51", feature = "luajit")), doc))]
+    #[cfg_attr(docsrs, doc(cfg(not(any(feature = "lua51", feature = "luajit")))))]
    pub num_params: u8,
-    /// Whether the function is a vararg function.
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau"))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau")))
-    )]
+    /// Whether the function is a variadic function (always true for C).
+    #[cfg(any(not(any(feature = "lua51", feature = "luajit")), doc))]
+    #[cfg_attr(docsrs, doc(cfg(not(any(feature = "lua51", feature = "luajit")))))]
    pub is_vararg: bool,
 }

@@ -337,6 +342,7 @@ impl HookTriggers {
    }

    // Compute the mask to pass to `lua_sethook`.
+    #[cfg(not(feature = "luau"))]
    pub(crate) const fn mask(&self) -> c_int {
        let mut mask: c_int = 0;
        if self.on_calls {
@@ -356,6 +362,7 @@ impl HookTriggers {

    // Returns the `count` parameter to pass to `lua_sethook`, if applicable. Otherwise, zero is
    // returned.
+    #[cfg(not(feature = "luau"))]
    pub(crate) const fn count(&self) -> c_int {
        match self.every_nth_instruction {
            Some(n) => n as c_int,
@@ -1,10 +1,14 @@
+//! Lua error handling.
+//!
+//! This module provides the [`Error`] type returned by all fallible `mlua` operations, together
+//! with extension traits for adapting Rust errors for use within Lua.
+
 use std::error::Error as StdError;
 use std::fmt;
 use std::io::Error as IoError;
 use std::net::AddrParseError;
 use std::result::Result as StdResult;
 use std::str::Utf8Error;
-use std::string::String as StdString;
 use std::sync::Arc;

 use crate::private::Sealed;
@@ -22,7 +26,7 @@ pub enum Error {
    /// Syntax error while parsing Lua source code.
    SyntaxError {
        /// The error message as returned by Lua.
-        message: StdString,
+        message: String,
        /// `true` if the error can likely be fixed by appending more input to the source code.
        ///
        /// This is useful for implementing REPLs as they can query the user for more input if this
@@ -34,20 +38,20 @@ pub enum Error {
    /// The Lua VM returns this error when a builtin operation is performed on incompatible types.
    /// Among other things, this includes invoking operators on wrong types (such as calling or
    /// indexing a `nil` value).
-    RuntimeError(StdString),
+    RuntimeError(String),
    /// Lua memory error, aka `LUA_ERRMEM`
    ///
    /// The Lua VM returns this error when the allocator does not return the requested memory, aka
    /// it is an out-of-memory error.
-    MemoryError(StdString),
+    MemoryError(String),
    /// Lua garbage collector error, aka `LUA_ERRGCMM`.
    ///
    /// The Lua VM returns this error when there is an error running a `__gc` metamethod.
    #[cfg(any(feature = "lua53", feature = "lua52", doc))]
    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua53", feature = "lua52"))))]
-    GarbageCollectorError(StdString),
+    GarbageCollectorError(String),
    /// Potentially unsafe action in safe mode.
-    SafetyError(StdString),
+    SafetyError(String),
    /// Memory control is not available.
    ///
    /// This error can only happen when Lua state was not created by us and does not have the
@@ -80,23 +84,14 @@ pub enum Error {
    /// (which is stored in the corresponding field).
    BadArgument {
        /// Function that was called.
-        to: Option<StdString>,
+        to: Option<String>,
        /// Argument position (usually starts from 1).
        pos: usize,
        /// Argument name.
-        name: Option<StdString>,
+        name: Option<String>,
        /// Underlying error returned when converting argument to a Lua value.
        cause: Arc<Error>,
    },
-    /// A Rust value could not be converted to a Lua value.
-    ToLuaConversionError {
-        /// Name of the Rust type that could not be converted.
-        from: String,
-        /// Name of the Lua type that could not be created.
-        to: &'static str,
-        /// A message indicating why the conversion failed in more detail.
-        message: Option<StdString>,
-    },
    /// A Lua value could not be converted to the expected Rust type.
    FromLuaConversionError {
        /// Name of the Lua type that could not be converted.
@@ -104,7 +99,7 @@ pub enum Error {
        /// Name of the Rust type that could not be created.
        to: String,
        /// A string containing more detailed error information.
-        message: Option<StdString>,
+        message: Option<String>,
    },
    /// [`Thread::resume`] was called on an unresumable coroutine.
    ///
@@ -154,17 +149,17 @@ pub enum Error {
    /// A [`MetaMethod`] operation is restricted (typically for `__gc` or `__metatable`).
    ///
    /// [`MetaMethod`]: crate::MetaMethod
-    MetaMethodRestricted(StdString),
+    MetaMethodRestricted(String),
    /// A [`MetaMethod`] (eg. `__index` or `__newindex`) has invalid type.
    ///
    /// [`MetaMethod`]: crate::MetaMethod
    MetaMethodTypeError {
        /// Name of the metamethod.
-        method: StdString,
+        method: String,
        /// Passed value type.
        type_name: &'static str,
        /// A string containing more detailed error information.
-        message: Option<StdString>,
+        message: Option<String>,
    },
    /// A [`RegistryKey`] produced from a different Lua state was used.
    ///
@@ -173,7 +168,7 @@ pub enum Error {
    /// A Rust callback returned `Err`, raising the contained `Error` as a Lua error.
    CallbackError {
        /// Lua call stack backtrace.
-        traceback: StdString,
+        traceback: String,
        /// Original error returned by the Rust code.
        cause: Arc<Error>,
    },
@@ -185,11 +180,11 @@ pub enum Error {
    /// Serialization error.
    #[cfg(feature = "serde")]
    #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
-    SerializeError(StdString),
+    SerializeError(String),
    /// Deserialization error.
    #[cfg(feature = "serde")]
    #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
-    DeserializeError(StdString),
+    DeserializeError(String),
    /// A custom error.
    ///
    /// This can be used for returning user-defined errors from callbacks.
@@ -201,7 +196,7 @@ pub enum Error {
    /// An error with additional context.
    WithContext {
        /// A string containing additional context.
-        context: StdString,
+        context: String,
        /// Underlying error.
        cause: Arc<Error>,
    },
@@ -225,7 +220,7 @@ impl fmt::Display for Error {
            }
            Error::SafetyError(msg) => {
                write!(fmt, "safety error: {msg}")
-            },
+            }
            Error::MemoryControlNotAvailable => {
                write!(fmt, "memory control is not available")
            }
@@ -238,10 +233,7 @@ impl fmt::Display for Error {
                fmt,
                "out of Lua stack, too many arguments to a Lua function or too many return values from a callback"
            ),
-            Error::BindError => write!(
-                fmt,
-                "too many arguments to Function::bind"
-            ),
+            Error::BindError => write!(fmt, "too many arguments to Function::bind"),
            Error::BadArgument { to, pos, name, cause } => {
                if let Some(name) = name {
                    write!(fmt, "bad argument `{name}`")?;
@@ -252,13 +244,6 @@ impl fmt::Display for Error {
                    write!(fmt, " to `{to}`")?;
                }
                write!(fmt, ": {cause}")
-            },
-            Error::ToLuaConversionError { from, to, message } => {
-                write!(fmt, "error converting {from} to Lua {to}")?;
-                match message {
-                    None => Ok(()),
-                    Some(message) => write!(fmt, " ({message})"),
-                }
            }
            Error::FromLuaConversionError { from, to, message } => {
                write!(fmt, "error converting Lua {from} to {to}")?;
@@ -273,7 +258,11 @@ impl fmt::Display for Error {
            Error::UserDataBorrowError => write!(fmt, "error borrowing userdata"),
            Error::UserDataBorrowMutError => write!(fmt, "error mutably borrowing userdata"),
            Error::MetaMethodRestricted(method) => write!(fmt, "metamethod {method} is restricted"),
-            Error::MetaMethodTypeError { method, type_name, message } => {
+            Error::MetaMethodTypeError {
+                method,
+                type_name,
+                message,
+            } => {
                write!(fmt, "metamethod {method} has unsupported type {type_name}")?;
                match message {
                    None => Ok(()),
@@ -286,7 +275,11 @@ impl fmt::Display for Error {
            Error::CallbackError { cause, traceback } => {
                // Trace errors down to the root
                let (mut cause, mut full_traceback) = (cause, None);
-                while let Error::CallbackError { cause: cause2, traceback: traceback2 } = &**cause {
+                while let Error::CallbackError {
+                    cause: cause2,
+                    traceback: traceback2,
+                } = &**cause
+                {
                    cause = cause2;
                    full_traceback = Some(traceback2);
                }
@@ -297,7 +290,7 @@ impl fmt::Display for Error {
                    // Try to find local traceback within the full traceback
                    if let Some(pos) = full_traceback.find(traceback) {
                        write!(fmt, "{}", &full_traceback[..pos])?;
-                        writeln!(fmt, ">{}", &full_traceback[pos..].trim_end())?;
+                        writeln!(fmt, ">{}", full_traceback[pos..].trim_end())?;
                    } else {
                        writeln!(fmt, "{}", full_traceback.trim_end())?;
                    }
@@ -312,11 +305,11 @@ impl fmt::Display for Error {
            #[cfg(feature = "serde")]
            Error::SerializeError(err) => {
                write!(fmt, "serialize error: {err}")
-            },
+            }
            #[cfg(feature = "serde")]
            Error::DeserializeError(err) => {
                write!(fmt, "deserialize error: {err}")
-            },
+            }
            Error::ExternalError(err) => err.fmt(fmt),
            Error::WithContext { context, cause } => {
                writeln!(fmt, "{context}")?;
@@ -352,7 +345,11 @@ impl Error {
    /// Wraps an external error object.
    #[inline]
    pub fn external<T: Into<Box<DynStdError>>>(err: T) -> Self {
-        Error::ExternalError(err.into().into())
+        let boxed = err.into();
+        match boxed.downcast::<Self>() {
+            Ok(err) => *err,
+            Err(boxed) => Error::ExternalError(boxed.into()),
+        }
    }

    /// Attempts to downcast the external error object to a concrete type by reference.
@@ -394,6 +391,7 @@ impl Error {
        }
    }

+    #[inline]
    pub(crate) fn from_lua_conversion(
        from: &'static str,
        to: impl ToString,
@@ -561,10 +559,8 @@ impl<'a> Iterator for Chain<'a> {

 #[cfg(test)]
 mod assertions {
-    use super::*;
-
    #[cfg(not(feature = "error-send"))]
-    static_assertions::assert_not_impl_any!(Error: Send, Sync);
+    static_assertions::assert_not_impl_any!(super::Error: Send, Sync);
    #[cfg(feature = "send")]
-    static_assertions::assert_impl_all!(Error: Send, Sync);
+    static_assertions::assert_impl_all!(super::Error: Send, Sync);
 }
@@ -1,24 +1,99 @@
+//! Lua function handling.
+//!
+//! This module provides types for working with Lua functions from Rust, including
+//! both Lua-defined functions and native Rust callbacks.
+//!
+//! # Calling Functions
+//!
+//! Use [`Function::call`] to invoke a Lua function synchronously:
+//!
+//! ```
+//! # use mlua::{Function, Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//!
+//! // Get a built-in function
+//! let print: Function = lua.globals().get("print")?;
+//! print.call::<()>("Hello from Rust!")?;
+//!
+//! // Call a function that returns values
+//! let tonumber: Function = lua.globals().get("tonumber")?;
+//! let n: i32 = tonumber.call("42")?;
+//! assert_eq!(n, 42);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! For asynchronous execution, use `Function::call_async` (requires `async` feature):
+//!
+//! ```ignore
+//! let result: String = my_async_func.call_async(args).await?;
+//! ```
+//!
+//! # Creating Functions
+//!
+//! Functions can be created from Rust closures using [`Lua::create_function`]:
+//!
+//! ```
+//! # use mlua::{Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//!
+//! let greet = lua.create_function(|_, name: String| {
+//!     Ok(format!("Hello, {}!", name))
+//! })?;
+//!
+//! lua.globals().set("greet", greet)?;
+//! let result: String = lua.load(r#"greet("World")"#).eval()?;
+//! assert_eq!(result, "Hello, World!");
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! For simpler cases, use [`Function::wrap`] or [`Function::wrap_raw`] to convert a Rust function
+//! directly:
+//!
+//! ```
+//! # use mlua::{Function, Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//!
+//! fn add(a: i32, b: i32) -> i32 { a + b }
+//!
+//! lua.globals().set("add", Function::wrap_raw(add))?;
+//! let sum: i32 = lua.load("add(2, 3)").eval()?;
+//! assert_eq!(sum, 5);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! # Function Environments
+//!
+//! Lua functions have an associated environment table that determines how global
+//! variables are resolved. Use [`Function::environment`] and [`Function::set_environment`]
+//! to inspect or modify this environment.
+
 use std::cell::RefCell;
 use std::os::raw::{c_int, c_void};
+use std::result::Result as StdResult;
 use std::{mem, ptr, slice};

-use crate::error::{Error, Result};
+use crate::error::{Error, ExternalError, ExternalResult, Result};
 use crate::state::Lua;
 use crate::table::Table;
-use crate::traits::{FromLuaMulti, IntoLua, IntoLuaMulti, LuaNativeFn, LuaNativeFnMut};
+use crate::traits::{FromLuaMulti, IntoLua, IntoLuaMulti};
 use crate::types::{Callback, LuaType, MaybeSend, ValueRef};
 use crate::util::{
-    assert_stack, check_stack, linenumber_to_usize, pop_error, ptr_to_lossy_str, ptr_to_str, StackGuard,
+    StackGuard, assert_stack, check_stack, linenumber_to_usize, pop_error, ptr_to_lossy_str, ptr_to_str,
 };
 use crate::value::Value;

 #[cfg(feature = "async")]
 use {
    crate::thread::AsyncThread,
-    crate::traits::LuaNativeAsyncFn,
    crate::types::AsyncCallback,
    std::future::{self, Future},
-    std::pin::{pin, Pin},
+    std::pin::{Pin, pin},
    std::task::{Context, Poll},
 };

@@ -32,6 +107,7 @@ pub struct Function(pub(crate) ValueRef);
 ///
 /// [`Lua Debug Interface`]: https://www.lua.org/manual/5.4/manual.html#4.7
 #[derive(Clone, Debug)]
+#[non_exhaustive]
 pub struct FunctionInfo {
    /// A (reasonable) name of the function (`None` if the name cannot be found).
    pub name: Option<String>,
@@ -50,6 +126,16 @@ pub struct FunctionInfo {
    pub line_defined: Option<usize>,
    /// The line number where the definition of the function ends (not set by Luau).
    pub last_line_defined: Option<usize>,
+    /// The number of upvalues of the function.
+    pub num_upvalues: u8,
+    /// The number of parameters of the function (always 0 for C).
+    #[cfg(any(not(any(feature = "lua51", feature = "luajit")), doc))]
+    #[cfg_attr(docsrs, doc(cfg(not(any(feature = "lua51", feature = "luajit")))))]
+    pub num_params: u8,
+    /// Whether the function is a variadic function (always true for C).
+    #[cfg(any(not(any(feature = "lua51", feature = "luajit")), doc))]
+    #[cfg_attr(docsrs, doc(cfg(not(any(feature = "lua51", feature = "luajit")))))]
+    pub is_vararg: bool,
 }

 /// Luau function coverage snapshot.
@@ -154,7 +240,7 @@ impl Function {
    /// # }
    /// ```
    ///
-    /// [`AsyncThread`]: crate::AsyncThread
+    /// [`AsyncThread`]: crate::thread::AsyncThread
    #[cfg(feature = "async")]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
    pub fn call_async<R>(&self, args: impl IntoLuaMulti) -> AsyncCallFuture<R>
@@ -276,7 +362,7 @@ impl Function {

            #[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
            ffi::lua_getfenv(state, -1);
-            #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
            for i in 1..=255 {
                // Traverse upvalues until we find the _ENV one
                match ffi::lua_getupvalue(state, -1, i) {
@@ -316,7 +402,7 @@ impl Function {
                lua.push_ref(&env.0);
                ffi::lua_setfenv(state, -2);
            }
-            #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
            for i in 1..=255 {
                match ffi::lua_getupvalue(state, -1, i) {
                    s if s.is_null() => return Ok(false),
@@ -343,7 +429,8 @@ impl Function {

    /// Returns information about the function.
    ///
-    /// Corresponds to the `>Sn` what mask for [`lua_getinfo`] when applied to the function.
+    /// Corresponds to the `>Snu` (`>Sn` for Luau) what mask for
+    /// [`lua_getinfo`] when applied to the function.
    ///
    /// [`lua_getinfo`]: https://www.lua.org/manual/5.4/manual.html#lua_getinfo
    pub fn info(&self) -> FunctionInfo {
@@ -355,11 +442,16 @@ impl Function {

            let mut ar: ffi::lua_Debug = mem::zeroed();
            lua.push_ref(&self.0);
+
            #[cfg(not(feature = "luau"))]
-            let res = ffi::lua_getinfo(state, cstr!(">Sn"), &mut ar);
+            let res = ffi::lua_getinfo(state, cstr!(">Snu"), &mut ar);
+            #[cfg(not(feature = "luau"))]
+            mlua_assert!(res != 0, "lua_getinfo failed with `>Snu`");
+
            #[cfg(feature = "luau")]
-            let res = ffi::lua_getinfo(state, -1, cstr!("sn"), &mut ar);
-            mlua_assert!(res != 0, "lua_getinfo failed with `>Sn`");
+            let res = ffi::lua_getinfo(state, -1, cstr!("snau"), &mut ar);
+            #[cfg(feature = "luau")]
+            mlua_assert!(res != 0, "lua_getinfo failed with `snau`");

            FunctionInfo {
                name: ptr_to_lossy_str(ar.name).map(|s| s.into_owned()),
@@ -381,6 +473,14 @@ impl Function {
                last_line_defined: linenumber_to_usize(ar.lastlinedefined),
                #[cfg(feature = "luau")]
                last_line_defined: None,
+                #[cfg(not(feature = "luau"))]
+                num_upvalues: ar.nups as _,
+                #[cfg(feature = "luau")]
+                num_upvalues: ar.nupvals,
+                #[cfg(not(any(feature = "lua51", feature = "luajit")))]
+                num_params: ar.nparams,
+                #[cfg(not(any(feature = "lua51", feature = "luajit")))]
+                is_vararg: ar.isvararg != 0,
            }
        }
    }
@@ -400,11 +500,14 @@ impl Function {
            _state: *mut ffi::lua_State,
            buf: *const c_void,
            buf_len: usize,
-            data: *mut c_void,
+            data_ptr: *mut c_void,
        ) -> c_int {
-            let data = &mut *(data as *mut Vec<u8>);
-            let buf = slice::from_raw_parts(buf as *const u8, buf_len);
-            data.extend_from_slice(buf);
+            // If `data` is null, then it's a signal that write is finished.
+            if !data_ptr.is_null() && buf_len > 0 {
+                let data = &mut *(data_ptr as *mut Vec<u8>);
+                let buf = slice::from_raw_parts(buf as *const u8, buf_len);
+                data.extend_from_slice(buf);
+            }
            0
        }

@@ -527,30 +630,32 @@ impl Function {
    /// Wraps a Rust function or closure, returning an opaque type that implements [`IntoLua`]
    /// trait.
    #[inline]
-    pub fn wrap<F, A, R>(func: F) -> impl IntoLua
+    pub fn wrap<F, A, R, E>(func: F) -> impl IntoLua
    where
-        F: LuaNativeFn<A, Output = Result<R>> + MaybeSend + 'static,
+        F: LuaNativeFn<A, Output = StdResult<R, E>> + MaybeSend + 'static,
        A: FromLuaMulti,
        R: IntoLuaMulti,
+        E: ExternalError,
    {
        WrappedFunction(Box::new(move |lua, nargs| unsafe {
            let args = A::from_stack_args(nargs, 1, None, lua)?;
-            func.call(args)?.push_into_stack_multi(lua)
+            func.call(args).into_lua_err()?.push_into_stack_multi(lua)
        }))
    }

    /// Wraps a Rust mutable closure, returning an opaque type that implements [`IntoLua`] trait.
-    pub fn wrap_mut<F, A, R>(func: F) -> impl IntoLua
+    pub fn wrap_mut<F, A, R, E>(func: F) -> impl IntoLua
    where
-        F: LuaNativeFnMut<A, Output = Result<R>> + MaybeSend + 'static,
+        F: LuaNativeFnMut<A, Output = StdResult<R, E>> + MaybeSend + 'static,
        A: FromLuaMulti,
        R: IntoLuaMulti,
+        E: ExternalError,
    {
        let func = RefCell::new(func);
        WrappedFunction(Box::new(move |lua, nargs| unsafe {
            let mut func = func.try_borrow_mut().map_err(|_| Error::RecursiveMutCallback)?;
            let args = A::from_stack_args(nargs, 1, None, lua)?;
-            func.call(args)?.push_into_stack_multi(lua)
+            func.call(args).into_lua_err()?.push_into_stack_multi(lua)
        }))
    }

@@ -563,6 +668,7 @@ impl Function {
    pub fn wrap_raw<F, A>(func: F) -> impl IntoLua
    where
        F: LuaNativeFn<A> + MaybeSend + 'static,
+        F::Output: IntoLuaMulti,
        A: FromLuaMulti,
    {
        WrappedFunction(Box::new(move |lua, nargs| unsafe {
@@ -579,6 +685,7 @@ impl Function {
    pub fn wrap_raw_mut<F, A>(func: F) -> impl IntoLua
    where
        F: LuaNativeFnMut<A> + MaybeSend + 'static,
+        F::Output: IntoLuaMulti,
        A: FromLuaMulti,
    {
        let func = RefCell::new(func);
@@ -593,11 +700,12 @@ impl Function {
    /// trait.
    #[cfg(feature = "async")]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    pub fn wrap_async<F, A, R>(func: F) -> impl IntoLua
+    pub fn wrap_async<F, A, R, E>(func: F) -> impl IntoLua
    where
-        F: LuaNativeAsyncFn<A, Output = Result<R>> + MaybeSend + 'static,
+        F: LuaNativeAsyncFn<A, Output = StdResult<R, E>> + MaybeSend + 'static,
        A: FromLuaMulti,
        R: IntoLuaMulti,
+        E: ExternalError,
    {
        WrappedAsyncFunction(Box::new(move |rawlua, nargs| unsafe {
            let args = match A::from_stack_args(nargs, 1, None, rawlua) {
@@ -606,7 +714,7 @@ impl Function {
            };
            let lua = rawlua.lua();
            let fut = func.call(args);
-            Box::pin(async move { fut.await?.push_into_stack_multi(lua.raw_lua()) })
+            Box::pin(async move { fut.await.into_lua_err()?.push_into_stack_multi(lua.raw_lua()) })
        }))
    }

@@ -620,6 +728,7 @@ impl Function {
    pub fn wrap_raw_async<F, A>(func: F) -> impl IntoLua
    where
        F: LuaNativeAsyncFn<A> + MaybeSend + 'static,
+        F::Output: IntoLuaMulti,
        A: FromLuaMulti,
    {
        WrappedAsyncFunction(Box::new(move |rawlua, nargs| unsafe {
@@ -653,7 +762,9 @@ impl LuaType for Function {
    const TYPE_ID: c_int = ffi::LUA_TFUNCTION;
 }

+/// Future for asynchronous function calls.
 #[cfg(feature = "async")]
+#[cfg_attr(docsrs, doc(cfg(feature = "async")))]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct AsyncCallFuture<R: FromLuaMulti>(Result<AsyncThread<R>>);

@@ -677,6 +788,94 @@ impl<R: FromLuaMulti> Future for AsyncCallFuture<R> {
    }
 }

+/// A trait for types that can be used as Lua functions.
+pub trait LuaNativeFn<A: FromLuaMulti> {
+    type Output;
+
+    fn call(&self, args: A) -> Self::Output;
+}
+
+/// A trait for types with mutable state that can be used as Lua functions.
+pub trait LuaNativeFnMut<A: FromLuaMulti> {
+    type Output;
+
+    fn call(&mut self, args: A) -> Self::Output;
+}
+
+/// A trait for types that returns a future and can be used as Lua functions.
+#[cfg(feature = "async")]
+pub trait LuaNativeAsyncFn<A: FromLuaMulti> {
+    type Output;
+
+    fn call(&self, args: A) -> impl Future<Output = Self::Output> + MaybeSend + 'static;
+}
+
+macro_rules! impl_lua_native_fn {
+    ($($A:ident),*) => {
+        impl<FN, $($A,)* R> LuaNativeFn<($($A,)*)> for FN
+        where
+            FN: Fn($($A,)*) -> R + MaybeSend + 'static,
+            ($($A,)*): FromLuaMulti,
+        {
+            type Output = R;
+
+            #[allow(non_snake_case)]
+            fn call(&self, args: ($($A,)*)) -> Self::Output {
+                let ($($A,)*) = args;
+                self($($A,)*)
+            }
+        }
+
+        impl<FN, $($A,)* R> LuaNativeFnMut<($($A,)*)> for FN
+        where
+            FN: FnMut($($A,)*) -> R + MaybeSend + 'static,
+            ($($A,)*): FromLuaMulti,
+        {
+            type Output = R;
+
+            #[allow(non_snake_case)]
+            fn call(&mut self, args: ($($A,)*)) -> Self::Output {
+                let ($($A,)*) = args;
+                self($($A,)*)
+            }
+        }
+
+        #[cfg(feature = "async")]
+        impl<FN, $($A,)* Fut, R> LuaNativeAsyncFn<($($A,)*)> for FN
+        where
+            FN: Fn($($A,)*) -> Fut + MaybeSend + 'static,
+            ($($A,)*): FromLuaMulti,
+            Fut: Future<Output = R> + MaybeSend + 'static,
+        {
+            type Output = R;
+
+            #[allow(non_snake_case)]
+            fn call(&self, args: ($($A,)*)) -> impl Future<Output = Self::Output> + MaybeSend + 'static {
+                let ($($A,)*) = args;
+                self($($A,)*)
+            }
+        }
+    };
+}
+
+impl_lua_native_fn!();
+impl_lua_native_fn!(A);
+impl_lua_native_fn!(A, B);
+impl_lua_native_fn!(A, B, C);
+impl_lua_native_fn!(A, B, C, D);
+impl_lua_native_fn!(A, B, C, D, E);
+impl_lua_native_fn!(A, B, C, D, E, F);
+impl_lua_native_fn!(A, B, C, D, E, F, G);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M, N);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O);
+impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P);
+
 #[cfg(test)]
 mod assertions {
    use super::*;
@@ -61,91 +61,108 @@
 //! [`Future`]: std::future::Future
 //! [`serde::Serialize`]: https://docs.serde.rs/serde/ser/trait.Serialize.html
 //! [`serde::Deserialize`]: https://docs.serde.rs/serde/de/trait.Deserialize.html
+//! [`AsyncThread`]: crate::thread::AsyncThread

 // Deny warnings inside doc tests / examples. When this isn't present, rustdoc doesn't show *any*
 // warnings at all.
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![cfg_attr(not(send), allow(clippy::arc_with_non_send_sync))]
-#![allow(clippy::ptr_eq)]
 #![allow(unsafe_op_in_unsafe_fn)]

 #[macro_use]
 mod macros;

 mod buffer;
-mod chunk;
 mod conversion;
-mod debug;
-mod error;
-mod function;
-#[cfg(any(feature = "luau", doc))]
-mod luau;
 mod memory;
 mod multi;
 mod scope;
-mod state;
 mod stdlib;
-mod string;
-mod table;
-mod thread;
 mod traits;
 mod types;
-mod userdata;
 mod util;
 mod value;
 mod vector;

+pub mod chunk;
+pub mod debug;
+pub mod error;
+pub mod function;
+#[cfg(any(feature = "luau", doc))]
+#[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
+pub mod luau;
 pub mod prelude;
+pub mod state;
+pub mod string;
+pub mod table;
+pub mod thread;
+pub mod userdata;

 pub use bstr::BString;
 pub use ffi::{self, lua_CFunction, lua_State};
+#[cfg(feature = "macros")]
+#[doc(hidden)]
+pub use inventory as __inventory;

-pub use crate::chunk::{AsChunk, Chunk, ChunkMode};
-pub use crate::debug::{Debug, DebugEvent, DebugNames, DebugSource, DebugStack};
-pub use crate::error::{Error, ErrorContext, ExternalError, ExternalResult, Result};
-pub use crate::function::{Function, FunctionInfo};
+#[doc(inline)]
+pub use crate::error::{Error, Result};
+#[doc(inline)]
+pub use crate::function::Function;
 pub use crate::multi::{MultiValue, Variadic};
 pub use crate::scope::Scope;
-pub use crate::state::{GCMode, Lua, LuaOptions, WeakLua};
+#[doc(inline)]
+pub use crate::state::{Lua, LuaOptions, WeakLua};
 pub use crate::stdlib::StdLib;
-pub use crate::string::{BorrowedBytes, BorrowedStr, String};
-pub use crate::table::{Table, TablePairs, TableSequence};
-pub use crate::thread::{Thread, ThreadStatus};
-pub use crate::traits::{
-    FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, LuaNativeFn, LuaNativeFnMut, ObjectLike,
-};
+#[doc(inline)]
+pub use crate::string::{BorrowedBytes, BorrowedStr, LuaString};
+#[doc(inline)]
+pub use crate::table::Table;
+#[doc(inline)]
+pub use crate::thread::Thread;
+#[doc(inline)]
+pub use crate::traits::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, ObjectLike};
 pub use crate::types::{
-    AppDataRef, AppDataRefMut, Either, Integer, LightUserData, MaybeSend, Number, RegistryKey, VmState,
-};
-pub use crate::userdata::{
-    AnyUserData, MetaMethod, UserData, UserDataFields, UserDataMetatable, UserDataMethods, UserDataRef,
-    UserDataRefMut, UserDataRegistry,
+    AppDataRef, AppDataRefMut, Either, Integer, LightUserData, MaybeSend, MaybeSync, Number, RegistryKey,
+    VmState,
 };
+#[doc(inline)]
+pub use crate::userdata::AnyUserData;
 pub use crate::value::{Nil, Value};

+// Re-export some types to keep backward compatibility and avoid breaking changes in the public API.
+#[doc(hidden)]
+pub use crate::chunk::{AsChunk, Chunk, ChunkMode};
+#[cfg(feature = "luau")]
+#[doc(hidden)]
+pub use crate::chunk::{CompileConstant, Compiler};
+#[doc(hidden)]
+pub use crate::error::{ErrorContext, ExternalError, ExternalResult};
+#[doc(hidden)]
+pub use crate::string::LuaString as String;
+#[doc(hidden)]
+pub use crate::table::{TablePairs, TableSequence};
+#[doc(hidden)]
+pub use crate::thread::{ThreadEvent, ThreadStatus, ThreadTriggers};
+#[doc(hidden)]
+pub use crate::userdata::{
+    MetaMethod, UserData, UserDataFields, UserDataMetatable, UserDataMethods, UserDataOwned, UserDataRef,
+    UserDataRefMut, UserDataRegistry,
+};
+
 #[cfg(not(feature = "luau"))]
+#[doc(inline)]
 pub use crate::debug::HookTriggers;

 #[cfg(any(feature = "luau", doc))]
 #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
-pub use crate::{
-    buffer::Buffer,
-    chunk::{CompileConstant, Compiler},
-    function::CoverageInfo,
-    luau::{HeapDump, NavigateError, Require, TextRequirer},
-    vector::Vector,
-};
-
-#[cfg(feature = "async")]
-#[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-pub use crate::{thread::AsyncThread, traits::LuaNativeAsyncFn};
+pub use crate::{buffer::Buffer, vector::Vector};

+#[cfg(feature = "serde")]
+#[doc(hidden)]
+pub use crate::serde::{DeserializeOptions, SerializeOptions};
 #[cfg(feature = "serde")]
 #[doc(inline)]
-pub use crate::{
-    serde::{de::Options as DeserializeOptions, ser::Options as SerializeOptions, LuaSerdeExt},
-    value::SerializableValue,
-};
+pub use crate::{serde::LuaSerdeExt, value::SerializableValue};

 #[cfg(feature = "serde")]
 #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
@@ -156,54 +173,7 @@ pub mod serde;
 #[macro_use]
 extern crate mlua_derive;

-/// Create a type that implements [`AsChunk`] and can capture Rust variables.
-///
-/// This macro allows to write Lua code directly in Rust code.
-///
-/// Rust variables can be referenced from Lua using `$` prefix, as shown in the example below.
-/// User's Rust types needs to implement [`UserData`] or [`IntoLua`] traits.
-///
-/// Captured variables are **moved** into the chunk.
-///
-/// ```
-/// use mlua::{Lua, Result, chunk};
-///
-/// fn main() -> Result<()> {
-///     let lua = Lua::new();
-///     let name = "Rustacean";
-///     lua.load(chunk! {
-///         print("hello, " .. $name)
-///     }).exec()
-/// }
-/// ```
-///
-/// ## Syntax issues
-///
-/// Since the Rust tokenizer will tokenize Lua code, this imposes some restrictions.
-/// The main thing to remember is:
-///
-/// - Use double quoted strings (`""`) instead of single quoted strings (`''`).
-///
-///   (Single quoted strings only work if they contain a single character, since in Rust,
-///   `'a'` is a character literal).
-///
-/// - Using Lua comments `--` is not desirable in **stable** Rust and can have bad side effects.
-///
-///   This is because procedural macros have Line/Column information available only in
-///   **nightly** Rust. Instead, Lua chunks represented as a big single line of code in stable Rust.
-///
-///   As workaround, Rust comments `//` can be used.
-///
-/// Other minor limitations:
-///
-/// - Certain escape codes in string literals don't work. (Specifically: `\a`, `\b`, `\f`, `\v`,
-///   `\123` (octal escape codes), `\u`, and `\U`).
-///
-///   These are accepted: : `\\`, `\n`, `\t`, `\r`, `\xAB` (hex escape codes), and `\0`.
-///
-/// - The `//` (floor division) operator is unusable, as its start a comment.
-///
-/// Everything else should work.
+#[doc = include_str!("../docs/chunk.md")]
 #[cfg(feature = "macros")]
 #[cfg_attr(docsrs, doc(cfg(feature = "macros")))]
 pub use mlua_derive::chunk;
@@ -216,47 +186,17 @@ pub use mlua_derive::chunk;
 #[cfg_attr(docsrs, doc(cfg(feature = "macros")))]
 pub use mlua_derive::FromLua;

-/// Registers Lua module entrypoint.
-///
-/// You can register multiple entrypoints as required.
-///
-/// ```ignore
-/// use mlua::{Lua, Result, Table};
-///
-/// #[mlua::lua_module]
-/// fn my_module(lua: &Lua) -> Result<Table> {
-///     let exports = lua.create_table()?;
-///     exports.set("hello", "world")?;
-///     Ok(exports)
-/// }
-/// ```
-///
-/// Internally in the code above the compiler defines C function `luaopen_my_module`.
-///
-/// You can also pass options to the attribute:
-///
-/// * name - name of the module, defaults to the name of the function
-///
-/// ```ignore
-/// #[mlua::lua_module(name = "alt_module")]
-/// fn my_module(lua: &Lua) -> Result<Table> {
-///     ...
-/// }
-/// ```
-///
-/// * skip_memory_check - skip memory allocation checks for some operations.
-///
-/// In module mode, mlua runs in unknown environment and cannot say are there any memory
-/// limits or not. As result, some operations that require memory allocation runs in
-/// protected mode. Setting this attribute will improve performance of such operations
-/// with risk of having uncaught exceptions and memory leaks.
-///
-/// ```ignore
-/// #[mlua::lua_module(skip_memory_check)]
-/// fn my_module(lua: &Lua) -> Result<Table> {
-///     ...
-/// }
-/// ```
+#[doc = include_str!("../docs/UserData.md")]
+#[cfg(feature = "macros")]
+#[cfg_attr(docsrs, doc(cfg(feature = "macros")))]
+pub use mlua_derive::UserData;
+
+#[doc(hidden)]
+#[cfg(feature = "macros")]
+#[cfg_attr(docsrs, doc(cfg(feature = "macros")))]
+pub use mlua_derive::userdata_impl;
+
+#[doc = include_str!("../docs/lua_module.md")]
 #[cfg(all(feature = "mlua_derive", any(feature = "module", doc)))]
 #[cfg_attr(docsrs, doc(cfg(feature = "module")))]
 pub use mlua_derive::lua_module;
@@ -79,10 +79,10 @@ impl HeapDump {
        let mut size_by_type = HashMap::new();
        let objects = self.data["objects"].as_object()?;
        for obj in objects.values() {
-            if let Some(cat_id) = category_id {
-                if obj["cat"].as_i64()? != cat_id {
-                    continue;
-                }
+            if let Some(cat_id) = category_id
+                && obj["cat"].as_i64()? != cat_id
+            {
+                continue;
            }
            update_size(&mut size_by_type, obj["type"].as_str()?, obj["size"].as_u64()?);
        }
@@ -123,18 +123,18 @@ impl HeapDump {
            if obj["type"] != "userdata" {
                continue;
            }
-            if let Some(cat_id) = category_id {
-                if obj["cat"].as_i64()? != cat_id {
-                    continue;
-                }
+            if let Some(cat_id) = category_id
+                && obj["cat"].as_i64()? != cat_id
+            {
+                continue;
            }

            // Determine userdata type from metatable
            let mut ud_type = "unknown";
-            if let Some(metatable_addr) = obj["metatable"].as_str() {
-                if let Some(t) = get_key(objects, &objects[metatable_addr], "__type") {
-                    ud_type = t;
-                }
+            if let Some(metatable_addr) = obj["metatable"].as_str()
+                && let Some(t) = get_key(objects, &objects[metatable_addr], "__type")
+            {
+                ud_type = t;
            }
            update_size(&mut size_by_userdata, ud_type, obj["size"].as_u64()?);
        }
@@ -155,7 +155,7 @@ impl HeapDump {

 /// Updates the size mapping for a given key.
 fn update_size<K: Eq + Hash>(size_type: &mut HashMap<K, (usize, u64)>, key: K, size: u64) {
-    let (ref mut count, ref mut total_size) = size_type.entry(key).or_insert((0, 0));
+    let (count, total_size) = size_type.entry(key).or_insert((0, 0));
    *count += 1;
    *total_size += size;
 }
@@ -313,8 +313,8 @@ mod tests {
    fn test_error_cases() {
        assert!(parse("").is_err());
        assert!(parse("nul").is_err());
-        assert!(parse("tru").is_err());
-        assert!(parse("fals").is_err());
+        assert!(parse("tru").is_err()); // typos:ignore
+        assert!(parse("fals").is_err()); // typos:ignore
        assert!(parse(r#""unterminated"#).is_err());
        assert!(parse("[1,2,]").is_err());
        assert!(parse(r#"{"key""#).is_err());
@@ -1,3 +1,10 @@
+//! Luau-specific extensions and types.
+//!
+//! This module provides Luau-specific functionality including custom [`require`] implementations,
+//! heap memory analysis, and Luau VM integration utilities.
+//!
+//! [`require`]: crate::Lua::create_require_function
+
 use std::ffi::{CStr, CString};
 use std::os::raw::c_int;
 use std::ptr;
@@ -5,12 +12,12 @@ use std::ptr;
 use crate::chunk::ChunkMode;
 use crate::error::{Error, Result};
 use crate::function::Function;
-use crate::state::{callback_error_ext, ExtraData, Lua};
+use crate::state::{ExtraData, Lua, callback_error_ext};
 use crate::traits::{FromLuaMulti, IntoLua};
 use crate::types::MaybeSend;

 pub use heap_dump::HeapDump;
-pub use require::{NavigateError, Require, TextRequirer};
+pub use require::{FsRequirer, NavigateError, Require};

 // Since Luau has some missing standard functions, we re-implement them here

@@ -86,7 +93,7 @@ impl Lua {
        }

        // Enable default `require` implementation
-        let require = self.create_require_function(require::TextRequirer::new())?;
+        let require = self.create_require_function(FsRequirer::new())?;
        self.globals().raw_set("require", require)?;

        Ok(())
@@ -8,12 +8,11 @@ use std::{fmt, mem, ptr};

 use crate::error::{Error, Result};
 use crate::function::Function;
-use crate::state::{callback_error_ext, Lua};
+use crate::state::{Lua, callback_error_ext};
 use crate::table::Table;
 use crate::types::MaybeSend;

-// TODO: Rename to FsRequirer
-pub use fs::TextRequirer;
+pub use fs::FsRequirer;

 /// An error that can occur during navigation in the Luau `require-by-string` system.
 #[derive(Debug, Clone)]
@@ -67,6 +66,24 @@ pub trait Require {
    /// configuration file.
    fn jump_to_alias(&mut self, path: &str) -> StdResult<(), NavigateError>;

+    /// Provides an initial alias override opportunity prior to searching for
+    /// configuration files.
+    ///
+    /// If `Ok(())` is returned, alias resolution stops here and the internal state
+    /// must point at the aliased location.
+    fn to_alias_override(&mut self, _alias: &str) -> StdResult<(), NavigateError> {
+        Err(NavigateError::NotFound)
+    }
+
+    /// Provides a final opportunity to resolve an alias if it cannot be found in
+    /// configuration files.
+    ///
+    /// If `Ok(())` is returned, alias resolution stops here and the internal state
+    /// must point at the aliased location.
+    fn to_alias_fallback(&mut self, _alias: &str) -> StdResult<(), NavigateError> {
+        Err(NavigateError::NotFound)
+    }
+
    // Navigate to parent directory
    fn to_parent(&mut self) -> StdResult<(), NavigateError>;

@@ -193,6 +210,30 @@ pub(super) unsafe extern "C-unwind" fn init_config(config: *mut ffi::luarequire_
        })
    }

+    unsafe extern "C-unwind" fn to_alias_override(
+        state: *mut ffi::lua_State,
+        ctx: *mut c_void,
+        alias_unprefixed: *const c_char,
+    ) -> ffi::luarequire_NavigateResult {
+        let mut this = try_borrow_mut!(state, ctx);
+        let alias = CStr::from_ptr(alias_unprefixed).to_string_lossy();
+        callback_error_ext(state, ptr::null_mut(), true, move |_, _| {
+            this.to_alias_override(&alias).into_nav_result()
+        })
+    }
+
+    unsafe extern "C-unwind" fn to_alias_fallback(
+        state: *mut ffi::lua_State,
+        ctx: *mut c_void,
+        alias_unprefixed: *const c_char,
+    ) -> ffi::luarequire_NavigateResult {
+        let mut this = try_borrow_mut!(state, ctx);
+        let alias = CStr::from_ptr(alias_unprefixed).to_string_lossy();
+        callback_error_ext(state, ptr::null_mut(), true, move |_, _| {
+            this.to_alias_fallback(&alias).into_nav_result()
+        })
+    }
+
    unsafe extern "C-unwind" fn to_parent(
        state: *mut ffi::lua_State,
        ctx: *mut c_void,
@@ -299,7 +340,8 @@ pub(super) unsafe extern "C-unwind" fn init_config(config: *mut ffi::luarequire_
    (*config).is_require_allowed = is_require_allowed;
    (*config).reset = reset;
    (*config).jump_to_alias = jump_to_alias;
-    (*config).to_alias_fallback = None;
+    (*config).to_alias_override = Some(to_alias_override);
+    (*config).to_alias_fallback = Some(to_alias_fallback);
    (*config).to_parent = to_parent;
    (*config).to_child = to_child;
    (*config).is_module_present = is_module_present;
@@ -12,7 +12,7 @@ use super::{NavigateError, Require};

 /// The standard implementation of Luau `require-by-string` navigation.
 #[derive(Default, Debug)]
-pub struct TextRequirer {
+pub struct FsRequirer {
    /// An absolute path to the current Luau module (not mapped to a physical file)
    abs_path: PathBuf,
    /// A relative path to the current Luau module (not mapped to a physical file)
@@ -22,7 +22,7 @@ pub struct TextRequirer {
    resolved_path: Option<PathBuf>,
 }

-impl TextRequirer {
+impl FsRequirer {
    /// The prefix used for chunk names in the require system.
    /// Only chunk names starting with this prefix are allowed to be used in `require`.
    const CHUNK_PREFIX: &str = "@";
@@ -36,16 +36,16 @@ impl TextRequirer {
    /// The filename for the Luau configuration file.
    const LUAU_CONFIG_FILENAME: &str = ".config.luau";

-    /// Creates a new `TextRequirer` instance.
+    /// Creates a new `FsRequirer` instance.
    pub fn new() -> Self {
        Self::default()
    }

    fn normalize_chunk_name(chunk_name: &str) -> &str {
-        if let Some((path, line)) = chunk_name.rsplit_once(':') {
-            if line.parse::<u32>().is_ok() {
-                return path;
-            }
+        if let Some((path, line)) = chunk_name.rsplit_once(':')
+            && line.parse::<u32>().is_ok()
+        {
+            return path;
        }
        chunk_name
    }
@@ -114,7 +114,7 @@ impl TextRequirer {
    }
 }

-impl Require for TextRequirer {
+impl Require for FsRequirer {
    fn is_require_allowed(&self, chunk_name: &str) -> bool {
        chunk_name.starts_with(Self::CHUNK_PREFIX)
    }
@@ -231,7 +231,7 @@ impl Require for TextRequirer {
 mod tests {
    use std::path::Path;

-    use super::TextRequirer;
+    use super::FsRequirer;

    #[test]
    fn test_path_normalize() {
@@ -267,7 +267,7 @@ mod tests {
            // '..' disappears if path is absolute and component is non-erasable
            ("/../", "/"),
        ] {
-            let path = TextRequirer::normalize_path(input.as_ref());
+            let path = FsRequirer::normalize_path(input.as_ref());
            assert_eq!(
                &path,
                expected.as_ref() as &Path,
@@ -28,9 +28,7 @@ impl MemoryState {
    }

    #[cfg(not(feature = "luau"))]
-    #[rustversion::since(1.85)]
    #[inline]
-    #[allow(clippy::incompatible_msrv)]
    pub(crate) unsafe fn get(state: *mut ffi::lua_State) -> *mut Self {
        let mut mem_state = ptr::null_mut();
        if !ptr::fn_addr_eq(ffi::lua_getallocf(state, &mut mem_state), ALLOCATOR) {
@@ -39,17 +37,6 @@ impl MemoryState {
        mem_state as *mut MemoryState
    }

-    #[cfg(not(feature = "luau"))]
-    #[rustversion::before(1.85)]
-    #[inline]
-    pub(crate) unsafe fn get(state: *mut ffi::lua_State) -> *mut Self {
-        let mut mem_state = ptr::null_mut();
-        if ffi::lua_getallocf(state, &mut mem_state) != ALLOCATOR {
-            mem_state = ptr::null_mut();
-        }
-        mem_state as *mut MemoryState
-    }
-
    #[inline]
    pub(crate) fn used_memory(&self) -> usize {
        self.used_memory as usize
@@ -83,7 +70,7 @@ impl MemoryState {
    }

    // Does nothing apart from calling `f()`, we don't need to bypass any limits
-    #[cfg(any(feature = "lua52", feature = "lua53", feature = "lua54"))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
    #[inline]
    pub(crate) unsafe fn relax_limit_with(_state: *mut ffi::lua_State, f: impl FnOnce()) {
        f();
@@ -1,4 +1,4 @@
-use std::collections::{vec_deque, VecDeque};
+use std::collections::{VecDeque, vec_deque};
 use std::iter::FromIterator;
 use std::mem;
 use std::ops::{Deref, DerefMut};
@@ -3,35 +3,44 @@
 #[doc(no_inline)]
 pub use crate::{
    AnyUserData as LuaAnyUserData, BorrowedBytes as LuaBorrowedBytes, BorrowedStr as LuaBorrowedStr,
-    Chunk as LuaChunk, Either as LuaEither, Error as LuaError, ErrorContext as LuaErrorContext,
-    ExternalError as LuaExternalError, ExternalResult as LuaExternalResult, FromLua, FromLuaMulti,
-    Function as LuaFunction, FunctionInfo as LuaFunctionInfo, GCMode as LuaGCMode, Integer as LuaInteger,
-    IntoLua, IntoLuaMulti, LightUserData as LuaLightUserData, Lua, LuaNativeFn, LuaNativeFnMut, LuaOptions,
-    MetaMethod as LuaMetaMethod, MultiValue as LuaMultiValue, Nil as LuaNil, Number as LuaNumber,
+    Either as LuaEither, Error as LuaError, FromLua, FromLuaMulti, Function as LuaFunction,
+    Integer as LuaInteger, IntoLua, IntoLuaMulti, LightUserData as LuaLightUserData, Lua, LuaOptions,
+    LuaString, MetaMethod as LuaMetaMethod, MultiValue as LuaMultiValue, Nil as LuaNil, Number as LuaNumber,
    ObjectLike as LuaObjectLike, RegistryKey as LuaRegistryKey, Result as LuaResult, StdLib as LuaStdLib,
-    String as LuaString, Table as LuaTable, TablePairs as LuaTablePairs, TableSequence as LuaTableSequence,
-    Thread as LuaThread, ThreadStatus as LuaThreadStatus, UserData as LuaUserData,
-    UserDataFields as LuaUserDataFields, UserDataMetatable as LuaUserDataMetatable,
-    UserDataMethods as LuaUserDataMethods, UserDataRef as LuaUserDataRef,
-    UserDataRefMut as LuaUserDataRefMut, UserDataRegistry as LuaUserDataRegistry, Value as LuaValue,
-    Variadic as LuaVariadic, VmState as LuaVmState, WeakLua,
+    Table as LuaTable, Thread as LuaThread, UserData as LuaUserData, UserDataFields as LuaUserDataFields,
+    UserDataMetatable as LuaUserDataMetatable, UserDataMethods as LuaUserDataMethods,
+    UserDataOwned as LuaUserDataOwned, UserDataRef as LuaUserDataRef, UserDataRefMut as LuaUserDataRefMut,
+    UserDataRegistry as LuaUserDataRegistry, Value as LuaValue, Variadic as LuaVariadic,
+    VmState as LuaVmState, WeakLua, chunk::AsChunk as AsLuaChunk, chunk::Chunk as LuaChunk,
+    chunk::ChunkMode as LuaChunkMode, error::ErrorContext as LuaErrorContext,
+    error::ExternalError as LuaExternalError, error::ExternalResult as LuaExternalResult,
+    function::FunctionInfo as LuaFunctionInfo, function::LuaNativeFn, function::LuaNativeFnMut,
+    state::GcIncParams as LuaGcIncParams, state::GcMode as LuaGcMode, table::TablePairs as LuaTablePairs,
+    table::TableSequence as LuaTableSequence, thread::ThreadStatus as LuaThreadStatus,
 };

 #[cfg(not(feature = "luau"))]
 #[doc(no_inline)]
 pub use crate::HookTriggers as LuaHookTriggers;

+#[cfg(any(feature = "lua54", feature = "lua55"))]
+#[doc(no_inline)]
+pub use crate::state::GcGenParams as LuaGcGenParams;
+
 #[cfg(feature = "luau")]
 #[doc(no_inline)]
 pub use crate::{
-    CompileConstant as LuaCompileConstant, CoverageInfo as LuaCoverageInfo,
-    NavigateError as LuaNavigateError, Require as LuaRequire, TextRequirer as LuaTextRequirer,
    Vector as LuaVector,
+    chunk::{CompileConstant as LuaCompileConstant, Compiler as LuaCompiler},
+    luau::{
+        FsRequirer as LuaFsRequirer, HeapDump as LuaHeapDump, NavigateError as LuaNavigateError,
+        Require as LuaRequire,
+    },
 };

 #[cfg(feature = "async")]
 #[doc(no_inline)]
-pub use crate::{AsyncThread as LuaAsyncThread, LuaNativeAsyncFn};
+pub use crate::{function::LuaNativeAsyncFn, thread::AsyncThread as LuaAsyncThread};

 #[cfg(feature = "serde")]
 #[doc(no_inline)]
@@ -8,7 +8,7 @@ use crate::state::{Lua, LuaGuard, RawLua};
 use crate::traits::{FromLuaMulti, IntoLuaMulti};
 use crate::types::{Callback, CallbackUpvalue, ScopedCallback, ValueRef};
 use crate::userdata::{AnyUserData, UserData, UserDataRegistry, UserDataStorage};
-use crate::util::{self, check_stack, get_metatable_ptr, get_userdata, take_userdata, StackGuard};
+use crate::util::{self, StackGuard, check_stack, get_metatable_ptr, get_userdata, take_userdata};

 /// Constructed by the [`Lua::scope`] method, allows temporarily creating Lua userdata and
 /// callbacks that are not required to be `Send` or `'static`.
@@ -4,7 +4,6 @@ use std::cell::RefCell;
 use std::os::raw::c_void;
 use std::rc::Rc;
 use std::result::Result as StdResult;
-use std::string::String as StdString;

 use rustc_hash::FxHashSet;
 use serde::de::{self, IntoDeserializer};
@@ -243,14 +242,14 @@ impl<'de> serde::Deserializer<'de> for Deserializer {
            Value::Table(table) => {
                let _guard = RecursionGuard::new(&table, &self.visited);

-                let mut iter = table.pairs::<StdString, Value>();
+                let mut iter = table.pairs::<String, Value>();
                let (variant, value) = match iter.next() {
                    Some(v) => v?,
                    None => {
                        return Err(de::Error::invalid_value(
                            de::Unexpected::Map,
                            &"map with a single key",
-                        ))
+                        ));
                    }
                };

@@ -621,7 +620,7 @@ impl<'de> de::MapAccess<'de> for MapDeserializer<'_> {
 }

 struct EnumDeserializer {
-    variant: StdString,
+    variant: String,
    value: Option<Value>,
    options: Options,
    visited: Rc<RefCell<FxHashSet<*const c_void>>>,
@@ -37,8 +37,8 @@ pub trait LuaSerdeExt: Sealed {
    fn null(&self) -> Value;

    /// A metatable attachable to a Lua table to systematically encode it as Array (instead of Map).
-    /// As result, encoded Array will contain only sequence part of the table, with the same length
-    /// as the `#` operator on that table.
+    /// As a result, encoded Array will contain only sequence part of the table, with the same
+    /// length as the `#` operator on that table.
    ///
    /// # Example
    ///
@@ -242,7 +242,5 @@ static ARRAY_METATABLE_REGISTRY_KEY: u8 = 0;
 pub mod de;
 pub mod ser;

-#[doc(inline)]
-pub use de::Deserializer;
-#[doc(inline)]
-pub use ser::Serializer;
+pub use de::{Deserializer, Options as DeserializeOptions};
+pub use ser::{Options as SerializeOptions, Serializer};
@@ -1,6 +1,6 @@
 //! Serialize a Rust data structure into Lua value.

-use serde::{ser, Serialize};
+use serde::{Serialize, ser};

 use super::LuaSerdeExt;
 use crate::error::{Error, Result};
@@ -531,10 +531,10 @@ impl ser::SerializeStruct for SerializeStruct<'_> {
            Some(table @ Value::Table(_)) => Ok(table),
            Some(value @ Value::String(_)) if self.options.detect_serde_json_arbitrary_precision => {
                let number_s = value.to_string()?;
-                if number_s.contains(['.', 'e', 'E']) {
-                    if let Ok(number) = number_s.parse().map(Value::Number) {
-                        return Ok(number);
-                    }
+                if number_s.contains(['.', 'e', 'E'])
+                    && let Ok(number) = number_s.parse().map(Value::Number)
+                {
+                    return Ok(number);
                }
                Ok(number_s
                    .parse()
@@ -1,3 +1,8 @@
+//! Lua state management.
+//!
+//! This module provides the main [`Lua`] state handle together with state-specific
+//! configuration and garbage collector controls.
+
 use std::any::TypeId;
 use std::cell::{BorrowError, BorrowMutError, RefCell};
 use std::marker::PhantomData;
@@ -15,16 +20,16 @@ use crate::memory::MemoryState;
 use crate::multi::MultiValue;
 use crate::scope::Scope;
 use crate::stdlib::StdLib;
-use crate::string::String;
+use crate::string::LuaString;
 use crate::table::Table;
-use crate::thread::Thread;
+use crate::thread::{Thread, ThreadEvent, ThreadTriggers};
 use crate::traits::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti};
 use crate::types::{
-    AppDataRef, AppDataRefMut, ArcReentrantMutexGuard, Integer, LuaType, MaybeSend, Number, ReentrantMutex,
-    ReentrantMutexGuard, RegistryKey, VmState, XRc, XWeak,
+    AppDataRef, AppDataRefMut, ArcReentrantMutexGuard, Integer, LuaType, MaybeSend, MaybeSync, Number,
+    ReentrantMutex, ReentrantMutexGuard, RegistryKey, VmState, XRc, XWeak,
 };
 use crate::userdata::{AnyUserData, UserData, UserDataProxy, UserDataRegistry, UserDataStorage};
-use crate::util::{assert_stack, check_stack, protect_lua_closure, push_string, rawset_field, StackGuard};
+use crate::util::{StackGuard, assert_stack, check_stack, protect_lua_closure, push_string, rawset_field};
 use crate::value::{Nil, Value};

 #[cfg(not(feature = "luau"))]
@@ -44,6 +49,7 @@ use {
 use serde::Serialize;

 pub(crate) use extra::ExtraData;
+#[doc(hidden)]
 pub use raw::RawLua;
 pub(crate) use util::callback_error_ext;

@@ -62,20 +68,126 @@ pub struct WeakLua(XWeak<ReentrantMutex<RawLua>>);

 pub(crate) struct LuaGuard(ArcReentrantMutexGuard<RawLua>);

-/// Mode of the Lua garbage collector (GC).
-///
-/// In Lua 5.4 GC can work in two modes: incremental and generational.
-/// Previous Lua versions support only incremental GC.
+/// Tuning parameters for the incremental GC collector.
 ///
 /// More information can be found in the Lua [documentation].
 ///
-/// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum GCMode {
-    Incremental,
-    #[cfg(feature = "lua54")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
-    Generational,
+/// [documentation]: https://www.lua.org/manual/5.5/manual.html#2.5.1
+#[non_exhaustive]
+#[derive(Clone, Copy, Debug, Default)]
+pub struct GcIncParams {
+    /// Pause between successive GC cycles, expressed as a percentage of live memory.
+    #[cfg(not(feature = "luau"))]
+    #[cfg_attr(docsrs, doc(cfg(not(feature = "luau"))))]
+    pub pause: Option<c_int>,
+
+    /// Target heap size as a percentage of live data, controlling how aggressively
+    /// the GC reclaims memory (`LUA_GCSETGOAL`).
+    #[cfg(any(feature = "luau", doc))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
+    pub goal: Option<c_int>,
+
+    /// GC work performed per unit of memory allocated.
+    pub step_multiplier: Option<c_int>,
+
+    /// Granularity of each GC step (see Lua reference for details).
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "luau"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54", feature = "luau"))))]
+    pub step_size: Option<c_int>,
+}
+
+impl GcIncParams {
+    /// Sets the `pause` parameter.
+    #[cfg(not(feature = "luau"))]
+    #[cfg_attr(docsrs, doc(cfg(not(feature = "luau"))))]
+    pub fn pause(mut self, v: c_int) -> Self {
+        self.pause = Some(v);
+        self
+    }
+
+    /// Sets the `goal` parameter.
+    #[cfg(any(feature = "luau", doc))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
+    pub fn goal(mut self, v: c_int) -> Self {
+        self.goal = Some(v);
+        self
+    }
+
+    /// Sets the `step_multiplier` parameter.
+    pub fn step_multiplier(mut self, v: c_int) -> Self {
+        self.step_multiplier = Some(v);
+        self
+    }
+
+    /// Sets the `step_size` parameter.
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "luau"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54", feature = "luau"))))]
+    pub fn step_size(mut self, v: c_int) -> Self {
+        self.step_size = Some(v);
+        self
+    }
+}
+
+/// Tuning parameters for the generational GC collector (Lua 5.4+).
+///
+/// More information can be found in the Lua [documentation].
+///
+/// [documentation]: https://www.lua.org/manual/5.5/manual.html#2.5.2
+#[cfg(any(feature = "lua55", feature = "lua54"))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54"))))]
+#[non_exhaustive]
+#[derive(Clone, Copy, Debug, Default)]
+pub struct GcGenParams {
+    /// Frequency of minor (young-generation) collection steps.
+    pub minor_multiplier: Option<c_int>,
+
+    /// Threshold controlling how large the young generation can grow before triggering
+    /// a shift from minor to major collection.
+    pub minor_to_major: Option<c_int>,
+
+    /// Threshold controlling how much the major collection must shrink the heap before
+    /// switching back to minor (young-generation) collection.
+    #[cfg(feature = "lua55")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "lua55")))]
+    pub major_to_minor: Option<c_int>,
+}
+
+#[cfg(any(feature = "lua55", feature = "lua54"))]
+impl GcGenParams {
+    /// Sets the `minor_multiplier` parameter.
+    pub fn minor_multiplier(mut self, v: c_int) -> Self {
+        self.minor_multiplier = Some(v);
+        self
+    }
+
+    /// Sets the `minor_to_major` threshold.
+    pub fn minor_to_major(mut self, v: c_int) -> Self {
+        self.minor_to_major = Some(v);
+        self
+    }
+
+    /// Sets the `major_to_minor` parameter.
+    #[cfg(feature = "lua55")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "lua55")))]
+    pub fn major_to_minor(mut self, v: c_int) -> Self {
+        self.major_to_minor = Some(v);
+        self
+    }
+}
+
+/// Lua garbage collector (GC) operating mode.
+///
+/// Use [`Lua::gc_set_mode`] to switch the collector mode and/or tune its parameters.
+#[non_exhaustive]
+#[derive(Clone, Debug)]
+pub enum GcMode {
+    /// Incremental mark-and-sweep
+    Incremental(GcIncParams),
+
+    /// Generational
+    #[cfg(any(feature = "lua55", feature = "lua54"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54"))))]
+    Generational(GcGenParams),
 }

 /// Controls Lua interpreter behavior such as Rust panics handling.
@@ -249,7 +361,7 @@ impl Lua {
            ffi::luaL_loadstring as _,
            ffi::luaL_openlibs as _,
        ]);
-        #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
        {
            _symbols.push(ffi::lua_getglobal as _);
            _symbols.push(ffi::lua_setglobal as _);
@@ -337,6 +449,36 @@ impl Lua {
        R::from_stack_multi(nresults, &lua)
    }

+    /// Calls provided function passing a reference to the [`RawLua`] handle.
+    ///
+    /// Provided [`RawLua`] handle can be used to manually pushing/popping values to/from the stack.
+    ///
+    /// # Example
+    /// ```
+    /// # use mlua::{Lua, Result, FromLua, IntoLua, IntoLuaMulti};
+    /// # fn main() -> Result<()> {
+    /// let lua = Lua::new();
+    /// let n: i32 = {
+    ///     let nums = (3, 4, 5);
+    ///     lua.exec_raw_lua(|rawlua| unsafe {
+    ///         nums.push_into_stack_multi(rawlua)?;
+    ///         let mut sum = 0;
+    ///         for _ in 0..3 {
+    ///             sum += rawlua.pop::<i32>()?;
+    ///         }
+    ///         Result::Ok(sum)
+    ///     })
+    /// }?;
+    /// assert_eq!(n, 12);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[doc(hidden)]
+    pub fn exec_raw_lua<R>(&self, f: impl FnOnce(&RawLua) -> R) -> R {
+        let lua = self.lock();
+        f(&lua)
+    }
+
    /// Loads the specified subset of the standard libraries into an existing Lua state.
    ///
    /// Use the [`StdLib`] flags to specify the libraries you want to load.
@@ -382,7 +524,7 @@ impl Lua {
    #[cfg(not(feature = "luau"))]
    #[cfg_attr(docsrs, doc(cfg(not(feature = "luau"))))]
    pub fn preload_module(&self, modname: &str, func: Function) -> Result<()> {
-        #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
        let preload = unsafe {
            self.exec_raw::<Option<Table>>((), |state| {
                ffi::lua_getfield(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_PRELOAD_TABLE);
@@ -404,31 +546,6 @@ impl Lua {
        Ok(())
    }

-    #[doc(hidden)]
-    #[deprecated(since = "0.11.0", note = "Use `register_module` instead")]
-    #[cfg(not(feature = "luau"))]
-    #[cfg(not(tarpaulin_include))]
-    pub fn load_from_function<T: FromLua>(&self, modname: &str, func: Function) -> Result<T> {
-        let loaded = unsafe {
-            self.exec_raw::<Table>((), |state| {
-                ffi::luaL_getsubtable(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_LOADED_TABLE);
-            })?
-        };
-
-        let value = match loaded.raw_get(modname)? {
-            Value::Nil => {
-                let result = match func.call(modname)? {
-                    Value::Nil => Value::Boolean(true),
-                    res => res,
-                };
-                loaded.raw_set(modname, &result)?;
-                result
-            }
-            res => res,
-        };
-        T::from_lua(value, self)
-    }
-
    /// Unloads module `modname`.
    ///
    /// This method does not support unloading binary Lua modules since they are internally cached
@@ -725,104 +842,98 @@ impl Lua {
        }
    }

-    /// Sets a thread creation callback that will be called when a thread is created.
-    #[cfg(any(feature = "luau", doc))]
-    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
-    pub fn set_thread_creation_callback<F>(&self, callback: F)
+    /// Sets a callback invoked when thread lifecycle events occur.
+    ///
+    /// `triggers` controls which events trigger the callback, see [`ThreadTriggers`] for more
+    /// details.
+    ///
+    /// Only one callback can be registered at a time. Calling this again replaces the previous
+    /// callback and its triggers.
+    ///
+    /// # Example
+    ///
+    /// Subscribe only to yield events:
+    ///
+    /// ```
+    /// # use mlua::{Lua, Result, ThreadTriggers, ThreadEvent};
+    /// # fn main() -> Result<()> {
+    /// let lua = Lua::new();
+    /// lua.set_thread_event_callback(
+    ///     ThreadTriggers::ON_YIELD,
+    ///     |_lua, event| {
+    ///         if let ThreadEvent::Yield(thread) = event {
+    ///             println!("thread yielded");
+    ///         }
+    ///         Ok(())
+    ///     },
+    /// );
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn set_thread_event_callback<F>(&self, triggers: ThreadTriggers, callback: F)
    where
-        F: Fn(&Lua, Thread) -> Result<()> + MaybeSend + 'static,
+        F: Fn(&Lua, ThreadEvent) -> Result<()> + MaybeSend + 'static,
    {
        let lua = self.lock();
        unsafe {
-            (*lua.extra.get()).thread_creation_callback = Some(XRc::new(callback));
-            (*ffi::lua_callbacks(lua.main_state())).userthread = Some(Self::userthread_proc);
+            (*lua.extra.get()).thread_triggers = triggers;
+            (*lua.extra.get()).thread_event_callback = Some(XRc::new(callback));
+            #[cfg(feature = "luau")]
+            {
+                let proc = Self::userthread_proc as _;
+                (*ffi::lua_callbacks(lua.main_state())).userthread = triggers.on_create.then_some(proc);
+            }
        }
    }

-    /// Sets a thread collection callback that will be called when a thread is destroyed.
+    /// Removes the thread event callback previously set by [`Lua::set_thread_event_callback`].
    ///
-    /// Luau GC does not support exceptions during collection, so the callback must be
-    /// non-panicking. If the callback panics, the program will be aborted.
-    #[cfg(any(feature = "luau", doc))]
-    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
-    pub fn set_thread_collection_callback<F>(&self, callback: F)
-    where
-        F: Fn(crate::LightUserData) + MaybeSend + 'static,
-    {
+    /// This function has no effect if a callback was not previously set.
+    pub fn remove_thread_event_callback(&self) {
        let lua = self.lock();
+        let extra = lua.extra.get();
        unsafe {
-            (*lua.extra.get()).thread_collection_callback = Some(XRc::new(callback));
-            (*ffi::lua_callbacks(lua.main_state())).userthread = Some(Self::userthread_proc);
+            (*extra).thread_triggers = ThreadTriggers::new();
+            (*extra).thread_event_callback = None;
+            #[cfg(feature = "luau")]
+            {
+                (*ffi::lua_callbacks(lua.main_state())).userthread = None;
+            }
        }
    }

    #[cfg(feature = "luau")]
    unsafe extern "C-unwind" fn userthread_proc(parent: *mut ffi::lua_State, child: *mut ffi::lua_State) {
+        // Only handle thread creation
+        if parent.is_null() {
+            return;
+        }
+
        let extra = ExtraData::get(child);
-        if !parent.is_null() {
-            // Thread is created
-            let callback = match (*extra).thread_creation_callback {
-                Some(ref cb) => cb.clone(),
-                None => return,
-            };
-            if XRc::strong_count(&callback) > 2 {
-                return; // Don't allow recursion
-            }
-            ffi::lua_pushthread(child);
-            ffi::lua_xmove(child, (*extra).ref_thread, 1);
-            let value = Thread((*extra).raw_lua().pop_ref_thread(), child);
-            callback_error_ext(parent, extra, false, move |extra, _| {
-                callback((*extra).lua(), value)
-            })
-        } else {
-            // Thread is about to be collected
-            let callback = match (*extra).thread_collection_callback {
-                Some(ref cb) => cb.clone(),
-                None => return,
-            };
-
-            // We need to wrap the callback call in non-unwind function as it's not safe to unwind when
-            // Luau GC is running.
-            // This will trigger `abort()` if the callback panics.
-            unsafe extern "C" fn run_callback(
-                callback: *const crate::types::ThreadCollectionCallback,
-                value: *mut ffi::lua_State,
-            ) {
-                (*callback)(crate::LightUserData(value as _));
-            }
-
-            (*extra).running_gc = true;
-            run_callback(&callback, child);
-            (*extra).running_gc = false;
-        }
-    }
-
-    /// Removes any thread creation or collection callbacks previously set by
-    /// [`Lua::set_thread_creation_callback`] or [`Lua::set_thread_collection_callback`].
-    ///
-    /// This function has no effect if a thread callbacks were not previously set.
-    #[cfg(any(feature = "luau", doc))]
-    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
-    pub fn remove_thread_callbacks(&self) {
-        let lua = self.lock();
-        unsafe {
-            let extra = lua.extra.get();
-            (*extra).thread_creation_callback = None;
-            (*extra).thread_collection_callback = None;
-            (*ffi::lua_callbacks(lua.main_state())).userthread = None;
+        if !(*extra).thread_triggers.on_create {
+            return;
        }
+        let callback = match &(*extra).thread_event_callback {
+            Some(cb) if XRc::strong_count(cb) == 1 => cb.clone(),
+            _ => return,
+        };
+        ffi::lua_pushthread(child);
+        ffi::lua_xmove(child, (*extra).ref_thread, 1);
+        let thread = Thread((*extra).raw_lua().pop_ref_thread(), child);
+        callback_error_ext(parent, extra, false, move |extra, _| {
+            callback((*extra).lua(), ThreadEvent::Create(thread))
+        })
    }

    /// Sets the warning function to be used by Lua to emit warnings.
-    #[cfg(feature = "lua54")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
+    #[cfg(any(feature = "lua55", feature = "lua54"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54"))))]
    pub fn set_warning_function<F>(&self, callback: F)
    where
        F: Fn(&Lua, &str, bool) -> Result<()> + MaybeSend + 'static,
    {
        use std::ffi::CStr;
        use std::os::raw::{c_char, c_void};
-        use std::string::String as StdString;

        unsafe extern "C-unwind" fn warn_proc(ud: *mut c_void, msg: *const c_char, tocont: c_int) {
            let extra = ud as *mut ExtraData;
@@ -832,7 +943,7 @@ impl Lua {
                if XRc::strong_count(&warn_callback) > 2 {
                    return Ok(());
                }
-                let msg = StdString::from_utf8_lossy(CStr::from_ptr(msg).to_bytes());
+                let msg = String::from_utf8_lossy(CStr::from_ptr(msg).to_bytes());
                warn_callback((*extra).lua(), &msg, tocont != 0)
            });
        }
@@ -847,8 +958,8 @@ impl Lua {
    /// Removes warning function previously set by `set_warning_function`.
    ///
    /// This function has no effect if a warning function was not previously set.
-    #[cfg(feature = "lua54")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
+    #[cfg(any(feature = "lua55", feature = "lua54"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54"))))]
    pub fn remove_warning_function(&self) {
        let lua = self.lock();
        unsafe {
@@ -861,8 +972,8 @@ impl Lua {
    ///
    /// A message in a call with `incomplete` set to `true` should be continued in
    /// another call to this function.
-    #[cfg(feature = "lua54")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
+    #[cfg(any(feature = "lua55", feature = "lua54"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54"))))]
    pub fn warning(&self, msg: impl AsRef<str>, incomplete: bool) {
        let msg = msg.as_ref();
        let mut bytes = vec![0; msg.len() + 1];
@@ -877,8 +988,8 @@ impl Lua {

    /// Gets information about the interpreter runtime stack at the given level.
    ///
-    /// This function calls callback `f`, passing the [`Debug`] structure that can be used to get
-    /// information about the function executing at a given level.
+    /// This function calls callback `f`, passing the [`struct@Debug`] structure that can be used to
+    /// get information about the function executing at a given level.
    /// Level `0` is the current running function, whereas level `n+1` is the function that has
    /// called level `n` (except for tail calls, which do not count in the stack).
    pub fn inspect_stack<R>(&self, level: usize, f: impl FnOnce(&Debug) -> R) -> Option<R> {
@@ -903,7 +1014,7 @@ impl Lua {
    ///
    /// The `msg` parameter, if provided, is added at the beginning of the traceback.
    /// The `level` parameter works the same way as in [`Lua::inspect_stack`].
-    pub fn traceback(&self, msg: Option<&str>, level: usize) -> Result<String> {
+    pub fn traceback(&self, msg: Option<&str>, level: usize) -> Result<LuaString> {
        let lua = self.lock();
        unsafe {
            check_stack(lua.state(), 3)?;
@@ -915,7 +1026,7 @@ impl Lua {
                // `protect_lua` adds it's own call frame, so we need to increase level by 1
                ffi::luaL_traceback(state, state, msg, (level + 1) as c_int);
            })?;
-            Ok(String(lua.pop_ref()))
+            Ok(LuaString(lua.pop_ref()))
        }
    }

@@ -954,25 +1065,31 @@ impl Lua {
    }

    /// Returns `true` if the garbage collector is currently running automatically.
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau"))]
+    #[cfg(any(
+        feature = "lua55",
+        feature = "lua54",
+        feature = "lua53",
+        feature = "lua52",
+        feature = "luau"
+    ))]
    pub fn gc_is_running(&self) -> bool {
        let lua = self.lock();
        unsafe { ffi::lua_gc(lua.main_state(), ffi::LUA_GCISRUNNING, 0) != 0 }
    }

-    /// Stop the Lua GC from running
+    /// Stops the Lua GC from running.
    pub fn gc_stop(&self) {
        let lua = self.lock();
        unsafe { ffi::lua_gc(lua.main_state(), ffi::LUA_GCSTOP, 0) };
    }

-    /// Restarts the Lua GC if it is not running
+    /// Restarts the Lua GC if it is not running.
    pub fn gc_restart(&self) {
        let lua = self.lock();
        unsafe { ffi::lua_gc(lua.main_state(), ffi::LUA_GCRESTART, 0) };
    }

-    /// Perform a full garbage-collection cycle.
+    /// Performs a full garbage-collection cycle.
    ///
    /// It may be necessary to call this function twice to collect all currently unreachable
    /// objects. Once to finish the current gc cycle, and once to start and finish the next cycle.
@@ -985,123 +1102,128 @@ impl Lua {
        }
    }

-    /// Steps the garbage collector one indivisible step.
+    /// Performs a basic step of garbage collection.
    ///
-    /// Returns `true` if this has finished a collection cycle.
+    /// In incremental mode, a basic step corresponds to the current step size. In generational
+    /// mode, a basic step performs a full minor collection or an incremental step, if the collector
+    /// has scheduled one.
+    ///
+    /// In incremental mode, returns `true` if this step has finished a collection cycle.
+    /// In generational mode, returns `true` if the step finished a major collection.
    pub fn gc_step(&self) -> Result<bool> {
-        self.gc_step_kbytes(0)
-    }
-
-    /// Steps the garbage collector as though memory had been allocated.
-    ///
-    /// if `kbytes` is 0, then this is the same as calling `gc_step`. Returns true if this step has
-    /// finished a collection cycle.
-    pub fn gc_step_kbytes(&self, kbytes: c_int) -> Result<bool> {
        let lua = self.lock();
        let state = lua.main_state();
        unsafe {
            check_stack(state, 3)?;
            protect_lua!(state, 0, 0, |state| {
-                ffi::lua_gc(state, ffi::LUA_GCSTEP, kbytes) != 0
+                ffi::lua_gc(state, ffi::LUA_GCSTEP, 0) != 0
            })
        }
    }

-    /// Sets the `pause` value of the collector.
+    /// Switches the GC to the given mode with the provided parameters.
    ///
-    /// Returns the previous value of `pause`. More information can be found in the Lua
-    /// [documentation].
+    /// Returns the previous [`GcMode`]. The returned value's parameter fields are always
+    /// `None` because Lua's C API does not provide a way to read back current parameter values
+    /// without changing them.
    ///
-    /// For Luau this parameter sets GC goal
+    /// # Examples
    ///
-    /// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5
-    pub fn gc_set_pause(&self, pause: c_int) -> c_int {
+    /// Switch to generational mode (Lua 5.4+):
+    /// ```ignore
+    /// let prev = lua.gc_set_mode(GcMode::Generational(GcGenParams::default()));
+    /// ```
+    ///
+    /// Switch to incremental mode with custom parameters:
+    /// ```ignore
+    /// lua.gc_set_mode(GcMode::Incremental(
+    ///     GcIncParams::default().pause(200).step_multiplier(100)
+    /// ));
+    /// ```
+    pub fn gc_set_mode(&self, mode: GcMode) -> GcMode {
        let lua = self.lock();
        let state = lua.main_state();
-        unsafe {
-            #[cfg(not(feature = "luau"))]
-            return ffi::lua_gc(state, ffi::LUA_GCSETPAUSE, pause);
+
+        match mode {
+            #[cfg(feature = "lua55")]
+            GcMode::Incremental(params) => unsafe {
+                if let Some(v) = params.pause {
+                    ffi::lua_gc(state, ffi::LUA_GCPARAM, ffi::LUA_GCPPAUSE, v);
+                }
+                if let Some(v) = params.step_multiplier {
+                    ffi::lua_gc(state, ffi::LUA_GCPARAM, ffi::LUA_GCPSTEPMUL, v);
+                }
+                if let Some(v) = params.step_size {
+                    ffi::lua_gc(state, ffi::LUA_GCPARAM, ffi::LUA_GCPSTEPSIZE, v);
+                }
+                match ffi::lua_gc(state, ffi::LUA_GCINC) {
+                    ffi::LUA_GCINC => GcMode::Incremental(GcIncParams::default()),
+                    ffi::LUA_GCGEN => GcMode::Generational(GcGenParams::default()),
+                    _ => unreachable!(),
+                }
+            },
+            #[cfg(feature = "lua54")]
+            GcMode::Incremental(params) => unsafe {
+                let pause = params.pause.unwrap_or(0);
+                let step_mul = params.step_multiplier.unwrap_or(0);
+                let step_size = params.step_size.unwrap_or(0);
+                match ffi::lua_gc(state, ffi::LUA_GCINC, pause, step_mul, step_size) {
+                    ffi::LUA_GCINC => GcMode::Incremental(GcIncParams::default()),
+                    ffi::LUA_GCGEN => GcMode::Generational(GcGenParams::default()),
+                    _ => unreachable!(),
+                }
+            },
+            #[cfg(any(feature = "lua53", feature = "lua52", feature = "lua51", feature = "luajit"))]
+            GcMode::Incremental(params) => unsafe {
+                if let Some(v) = params.pause {
+                    ffi::lua_gc(state, ffi::LUA_GCSETPAUSE, v);
+                }
+                if let Some(v) = params.step_multiplier {
+                    ffi::lua_gc(state, ffi::LUA_GCSETSTEPMUL, v);
+                }
+                GcMode::Incremental(GcIncParams::default())
+            },
            #[cfg(feature = "luau")]
-            return ffi::lua_gc(state, ffi::LUA_GCSETGOAL, pause);
-        }
-    }
+            GcMode::Incremental(params) => unsafe {
+                if let Some(v) = params.goal {
+                    ffi::lua_gc(state, ffi::LUA_GCSETGOAL, v);
+                }
+                if let Some(v) = params.step_multiplier {
+                    ffi::lua_gc(state, ffi::LUA_GCSETSTEPMUL, v);
+                }
+                if let Some(v) = params.step_size {
+                    ffi::lua_gc(state, ffi::LUA_GCSETSTEPSIZE, v);
+                }
+                GcMode::Incremental(GcIncParams::default())
+            },

-    /// Sets the `step multiplier` value of the collector.
-    ///
-    /// Returns the previous value of the `step multiplier`. More information can be found in the
-    /// Lua [documentation].
-    ///
-    /// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5
-    pub fn gc_set_step_multiplier(&self, step_multiplier: c_int) -> c_int {
-        let lua = self.lock();
-        unsafe { ffi::lua_gc(lua.main_state(), ffi::LUA_GCSETSTEPMUL, step_multiplier) }
-    }
-
-    /// Changes the collector to incremental mode with the given parameters.
-    ///
-    /// Returns the previous mode (always `GCMode::Incremental` in Lua < 5.4).
-    /// More information can be found in the Lua [documentation].
-    ///
-    /// [documentation]: https://www.lua.org/manual/5.4/manual.html#2.5.1
-    pub fn gc_inc(&self, pause: c_int, step_multiplier: c_int, step_size: c_int) -> GCMode {
-        let lua = self.lock();
-        let state = lua.main_state();
-
-        #[cfg(any(
-            feature = "lua53",
-            feature = "lua52",
-            feature = "lua51",
-            feature = "luajit",
-            feature = "luau"
-        ))]
-        unsafe {
-            if pause > 0 {
-                #[cfg(not(feature = "luau"))]
-                ffi::lua_gc(state, ffi::LUA_GCSETPAUSE, pause);
-                #[cfg(feature = "luau")]
-                ffi::lua_gc(state, ffi::LUA_GCSETGOAL, pause);
-            }
-
-            if step_multiplier > 0 {
-                ffi::lua_gc(state, ffi::LUA_GCSETSTEPMUL, step_multiplier);
-            }
-
-            #[cfg(feature = "luau")]
-            if step_size > 0 {
-                ffi::lua_gc(state, ffi::LUA_GCSETSTEPSIZE, step_size);
-            }
-            #[cfg(not(feature = "luau"))]
-            let _ = step_size; // Ignored
-
-            GCMode::Incremental
-        }
-
-        #[cfg(feature = "lua54")]
-        let prev_mode = unsafe { ffi::lua_gc(state, ffi::LUA_GCINC, pause, step_multiplier, step_size) };
-        #[cfg(feature = "lua54")]
-        match prev_mode {
-            ffi::LUA_GCINC => GCMode::Incremental,
-            ffi::LUA_GCGEN => GCMode::Generational,
-            _ => unreachable!(),
-        }
-    }
-
-    /// Changes the collector to generational mode with the given parameters.
-    ///
-    /// Returns the previous mode. More information about the generational GC
-    /// can be found in the Lua 5.4 [documentation][lua_doc].
-    ///
-    /// [lua_doc]: https://www.lua.org/manual/5.4/manual.html#2.5.2
-    #[cfg(feature = "lua54")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
-    pub fn gc_gen(&self, minor_multiplier: c_int, major_multiplier: c_int) -> GCMode {
-        let lua = self.lock();
-        let state = lua.main_state();
-        let prev_mode = unsafe { ffi::lua_gc(state, ffi::LUA_GCGEN, minor_multiplier, major_multiplier) };
-        match prev_mode {
-            ffi::LUA_GCGEN => GCMode::Generational,
-            ffi::LUA_GCINC => GCMode::Incremental,
-            _ => unreachable!(),
+            #[cfg(feature = "lua55")]
+            GcMode::Generational(params) => unsafe {
+                if let Some(v) = params.minor_multiplier {
+                    ffi::lua_gc(state, ffi::LUA_GCPARAM, ffi::LUA_GCPMINORMUL, v);
+                }
+                if let Some(v) = params.minor_to_major {
+                    ffi::lua_gc(state, ffi::LUA_GCPARAM, ffi::LUA_GCPMINORMAJOR, v);
+                }
+                if let Some(v) = params.major_to_minor {
+                    ffi::lua_gc(state, ffi::LUA_GCPARAM, ffi::LUA_GCPMAJORMINOR, v);
+                }
+                match ffi::lua_gc(state, ffi::LUA_GCGEN) {
+                    ffi::LUA_GCGEN => GcMode::Generational(GcGenParams::default()),
+                    ffi::LUA_GCINC => GcMode::Incremental(GcIncParams::default()),
+                    _ => unreachable!(),
+                }
+            },
+            #[cfg(feature = "lua54")]
+            GcMode::Generational(params) => unsafe {
+                let minor = params.minor_multiplier.unwrap_or(0);
+                let minor_to_major = params.minor_to_major.unwrap_or(0);
+                match ffi::lua_gc(state, ffi::LUA_GCGEN, minor, minor_to_major) {
+                    ffi::LUA_GCGEN => GcMode::Generational(GcGenParams::default()),
+                    ffi::LUA_GCINC => GcMode::Incremental(GcIncParams::default()),
+                    _ => unreachable!(),
+                }
+            },
        }
    }

@@ -1136,10 +1258,10 @@ impl Lua {
    #[doc(hidden)]
    #[allow(clippy::result_unit_err)]
    pub fn set_fflag(name: &str, enabled: bool) -> StdResult<(), ()> {
-        if let Ok(name) = std::ffi::CString::new(name) {
-            if unsafe { ffi::luau_setfflag(name.as_ptr(), enabled as c_int) != 0 } {
-                return Ok(());
-            }
+        if let Ok(name) = std::ffi::CString::new(name)
+            && unsafe { ffi::luau_setfflag(name.as_ptr(), enabled as c_int) != 0 }
+        {
+            return Ok(());
        }
        Err(())
    }
@@ -1179,10 +1301,21 @@ impl Lua {
    /// Lua strings can be arbitrary `[u8]` data including embedded nulls, so in addition to `&str`
    /// and `&String`, you can also pass plain `&[u8]` here.
    #[inline]
-    pub fn create_string(&self, s: impl AsRef<[u8]>) -> Result<String> {
+    pub fn create_string(&self, s: impl AsRef<[u8]>) -> Result<LuaString> {
        unsafe { self.lock().create_string(s.as_ref()) }
    }

+    /// Creates and returns an external Lua string.
+    ///
+    /// External string is a string where the memory is managed by Rust code, and Lua only holds a
+    /// reference to it. This can be used to avoid copying large strings into Lua memory.
+    #[cfg(feature = "lua55")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "lua55")))]
+    #[inline]
+    pub fn create_external_string(&self, s: impl Into<Vec<u8>>) -> Result<LuaString> {
+        unsafe { self.lock().create_external_string(s.into()) }
+    }
+
    /// Creates and returns a Luau [buffer] object from a byte slice of data.
    ///
    /// [buffer]: https://luau.org/library#buffer-library
@@ -1317,7 +1450,12 @@ impl Lua {
    /// This function is unsafe because provides a way to execute unsafe C function.
    pub unsafe fn create_c_function(&self, func: ffi::lua_CFunction) -> Result<Function> {
        let lua = self.lock();
-        if cfg!(any(feature = "lua54", feature = "lua53", feature = "lua52")) {
+        if cfg!(any(
+            feature = "lua55",
+            feature = "lua54",
+            feature = "lua53",
+            feature = "lua52"
+        )) {
            ffi::lua_pushcfunction(lua.ref_thread(), func);
            return Ok(Function(lua.pop_ref_thread()));
        }
@@ -1372,7 +1510,7 @@ impl Lua {
    /// }
    /// ```
    ///
-    /// [`AsyncThread`]: crate::AsyncThread
+    /// [`AsyncThread`]: crate::thread::AsyncThread
    #[cfg(feature = "async")]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
    pub fn create_async_function<F, A, FR, R>(&self, func: F) -> Result<Function>
@@ -1408,7 +1546,7 @@ impl Lua {
    #[inline]
    pub fn create_userdata<T>(&self, data: T) -> Result<AnyUserData>
    where
-        T: UserData + MaybeSend + 'static,
+        T: UserData + MaybeSend + MaybeSync + 'static,
    {
        unsafe { self.lock().make_userdata(UserDataStorage::new(data)) }
    }
@@ -1419,7 +1557,7 @@ impl Lua {
    #[inline]
    pub fn create_ser_userdata<T>(&self, data: T) -> Result<AnyUserData>
    where
-        T: UserData + Serialize + MaybeSend + 'static,
+        T: UserData + Serialize + MaybeSend + MaybeSync + 'static,
    {
        unsafe { self.lock().make_userdata(UserDataStorage::new_ser(data)) }
    }
@@ -1434,7 +1572,7 @@ impl Lua {
    #[inline]
    pub fn create_any_userdata<T>(&self, data: T) -> Result<AnyUserData>
    where
-        T: MaybeSend + 'static,
+        T: MaybeSend + MaybeSync + 'static,
    {
        unsafe { self.lock().make_any_userdata(UserDataStorage::new(data)) }
    }
@@ -1447,7 +1585,7 @@ impl Lua {
    #[inline]
    pub fn create_ser_any_userdata<T>(&self, data: T) -> Result<AnyUserData>
    where
-        T: Serialize + MaybeSend + 'static,
+        T: Serialize + MaybeSend + MaybeSync + 'static,
    {
        unsafe { (self.lock()).make_any_userdata(UserDataStorage::new_ser(data)) }
    }
@@ -1578,7 +1716,7 @@ impl Lua {
        unsafe {
            let _sg = StackGuard::new(state);
            assert_stack(state, 1);
-            #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
            ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_RIDX_GLOBALS);
            #[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
            ffi::lua_pushvalue(state, ffi::LUA_GLOBALSINDEX);
@@ -1610,7 +1748,7 @@ impl Lua {

            lua.push_ref(&globals.0);

-            #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
            ffi::lua_rawseti(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_RIDX_GLOBALS);
            #[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
            ffi::lua_replace(state, ffi::LUA_GLOBALSINDEX);
@@ -1656,7 +1794,7 @@ impl Lua {
    ///
    /// To succeed, the value must be a string (in which case this is a no-op), an integer, or a
    /// number.
-    pub fn coerce_string(&self, v: Value) -> Result<Option<String>> {
+    pub fn coerce_string(&self, v: Value) -> Result<Option<LuaString>> {
        Ok(match v {
            Value::String(s) => Some(s),
            v => unsafe {
@@ -1674,7 +1812,7 @@ impl Lua {
                    })?
                };
                if !res.is_null() {
-                    Some(String(lua.pop_ref()))
+                    Some(LuaString(lua.pop_ref()))
                } else {
                    None
                }
@@ -1700,11 +1838,7 @@ impl Lua {
                lua.push_value(&v)?;
                let mut isint = 0;
                let i = ffi::lua_tointegerx(state, -1, &mut isint);
-                if isint == 0 {
-                    None
-                } else {
-                    Some(i)
-                }
+                if isint == 0 { None } else { Some(i) }
            },
        })
    }
@@ -1726,11 +1860,7 @@ impl Lua {
                lua.push_value(&v)?;
                let mut isnum = 0;
                let n = ffi::lua_tonumberx(state, -1, &mut isnum);
-                if isnum == 0 {
-                    None
-                } else {
-                    Some(n)
-                }
+                if isnum == 0 { None } else { Some(n) }
            },
        })
    }
@@ -2098,7 +2228,7 @@ impl Lua {

    /// Suspends the current async function, returning the provided arguments to caller.
    ///
-    /// This function is similar to [`coroutine.yield`] but allow yeilding Rust functions
+    /// This function is similar to [`coroutine.yield`] but allow yielding Rust functions
    /// and passing values to the caller.
    /// Please note that you cannot cross [`Thread`] boundaries (e.g. calling `yield_with` on one
    /// thread and resuming on another).
@@ -2210,7 +2340,7 @@ impl Lua {
            })?,
        )?;

-        #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
        let searchers: Table = package.get("searchers")?;
        #[cfg(any(feature = "lua51", feature = "luajit"))]
        let searchers: Table = package.get("loaders")?;
@@ -12,9 +12,10 @@ use rustc_hash::FxHashMap;
 use crate::error::Result;
 use crate::state::RawLua;
 use crate::stdlib::StdLib;
-use crate::types::{AppData, ReentrantMutex, XRc};
+use crate::thread::ThreadTriggers;
+use crate::types::{AppData, ReentrantMutex, ThreadEventCallback, XRc};
 use crate::userdata::RawUserDataRegistry;
-use crate::util::{get_internal_metatable, push_internal_userdata, TypeKey, WrappedFailure};
+use crate::util::{TypeKey, WrappedFailure, get_internal_metatable, push_internal_userdata};

 #[cfg(any(feature = "luau", doc))]
 use crate::chunk::Compiler;
@@ -77,14 +78,12 @@ pub(crate) struct ExtraData {
    pub(super) hook_callback: Option<crate::types::HookCallback>,
    #[cfg(not(feature = "luau"))]
    pub(super) hook_triggers: crate::debug::HookTriggers,
-    #[cfg(feature = "lua54")]
+    #[cfg(any(feature = "lua55", feature = "lua54"))]
    pub(super) warn_callback: Option<crate::types::WarnCallback>,
    #[cfg(feature = "luau")]
    pub(super) interrupt_callback: Option<crate::types::InterruptCallback>,
-    #[cfg(feature = "luau")]
-    pub(super) thread_creation_callback: Option<crate::types::ThreadCreationCallback>,
-    #[cfg(feature = "luau")]
-    pub(super) thread_collection_callback: Option<crate::types::ThreadCollectionCallback>,
+    pub(super) thread_triggers: ThreadTriggers,
+    pub(super) thread_event_callback: Option<ThreadEventCallback>,

    #[cfg(feature = "luau")]
    pub(crate) running_gc: bool,
@@ -182,14 +181,12 @@ impl ExtraData {
            hook_callback: None,
            #[cfg(not(feature = "luau"))]
            hook_triggers: Default::default(),
-            #[cfg(feature = "lua54")]
+            #[cfg(any(feature = "lua55", feature = "lua54"))]
            warn_callback: None,
            #[cfg(feature = "luau")]
            interrupt_callback: None,
-            #[cfg(feature = "luau")]
-            thread_creation_callback: None,
-            #[cfg(feature = "luau")]
-            thread_collection_callback: None,
+            thread_triggers: ThreadTriggers::default(),
+            thread_event_callback: None,
            #[cfg(feature = "luau")]
            sandboxed: false,
            #[cfg(feature = "luau")]
@@ -1,7 +1,7 @@
 use std::any::TypeId;
 use std::cell::{Cell, UnsafeCell};
 use std::ffi::CStr;
-use std::mem;
+use std::mem::{self, ManuallyDrop};
 use std::os::raw::{c_char, c_int, c_void};
 use std::panic::resume_unwind;
 use std::ptr::{self, NonNull};
@@ -10,26 +10,26 @@ use std::sync::Arc;
 use crate::chunk::ChunkMode;
 use crate::error::{Error, Result};
 use crate::function::Function;
-use crate::memory::{MemoryState, ALLOCATOR};
+use crate::memory::{ALLOCATOR, MemoryState};
 use crate::state::util::callback_error_ext;
 use crate::stdlib::StdLib;
-use crate::string::String;
+use crate::string::LuaString;
 use crate::table::Table;
-use crate::thread::Thread;
-use crate::traits::IntoLua;
+use crate::thread::{Thread, ThreadTriggers};
+use crate::traits::{FromLua, IntoLua};
 use crate::types::{
    AppDataRef, AppDataRefMut, Callback, CallbackUpvalue, DestructedUserdata, Integer, LightUserData,
-    LuaType, MaybeSend, ReentrantMutex, RegistryKey, ValueRef, XRc,
+    LuaType, MaybeSend, ReentrantMutex, RegistryKey, ThreadEventCallback, ValueRef, XRc,
 };
 use crate::userdata::{
-    init_userdata_metatable, AnyUserData, MetaMethod, RawUserDataRegistry, UserData, UserDataRegistry,
-    UserDataStorage,
+    AnyUserData, MetaMethod, RawUserDataRegistry, UserData, UserDataRegistry, UserDataStorage,
+    init_userdata_metatable,
 };
 use crate::util::{
-    assert_stack, check_stack, get_destructed_userdata_metatable, get_internal_userdata, get_main_state,
-    get_metatable_ptr, get_userdata, init_error_registry, init_internal_metatable, pop_error,
-    push_internal_userdata, push_string, push_table, push_userdata, rawset_field, safe_pcall, safe_xpcall,
-    short_type_name, StackGuard, WrappedFailure,
+    StackGuard, WrappedFailure, assert_stack, check_stack, get_destructed_userdata_metatable,
+    get_internal_userdata, get_main_state, get_metatable_ptr, get_userdata, init_error_registry,
+    init_internal_metatable, pop_error, push_internal_userdata, push_string, push_table, push_userdata,
+    rawset_field, safe_pcall, safe_xpcall, short_type_name,
 };
 use crate::value::{Nil, Value};

@@ -50,13 +50,13 @@ use {
    std::task::{Context, Poll, Waker},
 };

-/// An inner Lua struct which holds a raw Lua state.
+/// An internal Lua struct which holds a raw Lua state.
 #[doc(hidden)]
 pub struct RawLua {
    // The state is dynamic and depends on context
    pub(super) state: Cell<*mut ffi::lua_State>,
    pub(super) main_state: Option<NonNull<ffi::lua_State>>,
-    pub(super) extra: XRc<UnsafeCell<ExtraData>>,
+    pub(super) extra: ManuallyDrop<XRc<UnsafeCell<ExtraData>>>,
    owned: bool,
 }

@@ -82,6 +82,9 @@ impl Drop for RawLua {
            if !mem_state.is_null() {
                drop(Box::from_raw(mem_state));
            }
+
+            // Drop the `ExtraData` reference after `lua_close` has collected the registry entry
+            ManuallyDrop::drop(&mut self.extra);
        }
    }
 }
@@ -122,6 +125,12 @@ impl RawLua {

    pub(super) unsafe fn new(libs: StdLib, options: &LuaOptions) -> XRc<ReentrantMutex<Self>> {
        let mem_state: *mut MemoryState = Box::into_raw(Box::default());
+        #[cfg(feature = "lua55")]
+        let mut state = {
+            let seed = ffi::luaL_makeseed(ptr::null_mut());
+            ffi::lua_newstate(ALLOCATOR, mem_state as *mut c_void, seed)
+        };
+        #[cfg(not(feature = "lua55"))]
        let mut state = ffi::lua_newstate(ALLOCATOR, mem_state as *mut c_void);
        // If state is null then switch to Lua internal allocator
        if state.is_null() {
@@ -153,7 +162,7 @@ impl RawLua {
                (|| -> Result<()> {
                    let _sg = StackGuard::new(state);

-                    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+                    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
                    ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_RIDX_GLOBALS);
                    #[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
                    ffi::lua_pushvalue(state, ffi::LUA_GLOBALSINDEX);
@@ -239,7 +248,7 @@ impl RawLua {
            state: Cell::new(state),
            // Make sure that we don't store current state as main state (if it's not available)
            main_state: get_main_state(state).and_then(NonNull::new),
-            extra: XRc::clone(&extra),
+            extra: ManuallyDrop::new(XRc::clone(&extra)),
            owned,
        }));
        (*extra.get()).set_lua(&rawlua);
@@ -416,7 +425,7 @@ impl RawLua {
                VmState::Yield => {
                    // Only count and line events can yield
                    if event == ffi::LUA_HOOKCOUNT || event == ffi::LUA_HOOKLINE {
-                        #[cfg(any(feature = "lua54", feature = "lua53"))]
+                        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
                        if ffi::lua_isyieldable(state) != 0 {
                            ffi::lua_yield(state, 0);
                        }
@@ -510,17 +519,34 @@ impl RawLua {
    }

    /// See [`Lua::create_string`]
-    pub(crate) unsafe fn create_string(&self, s: &[u8]) -> Result<String> {
+    pub(crate) unsafe fn create_string(&self, s: &[u8]) -> Result<LuaString> {
        let state = self.state();
        if self.unlikely_memory_error() {
            push_string(state, s, false)?;
-            return Ok(String(self.pop_ref()));
+            return Ok(LuaString(self.pop_ref()));
        }

        let _sg = StackGuard::new(state);
        check_stack(state, 3)?;
        push_string(state, s, true)?;
-        Ok(String(self.pop_ref()))
+        Ok(LuaString(self.pop_ref()))
+    }
+
+    /// Creates an external string, that is, a string that uses memory not managed by Lua.
+    ///
+    /// Modifies the input data to add `\0` terminator.
+    #[cfg(feature = "lua55")]
+    pub(crate) unsafe fn create_external_string(&self, bytes: Vec<u8>) -> Result<LuaString> {
+        let state = self.state();
+        if self.unlikely_memory_error() {
+            crate::util::push_external_string(state, bytes, false)?;
+            return Ok(LuaString(self.pop_ref()));
+        }
+
+        let _sg = StackGuard::new(state);
+        check_stack(state, 3)?;
+        crate::util::push_external_string(state, bytes, true)?;
+        Ok(LuaString(self.pop_ref()))
    }

    #[cfg(feature = "luau")]
@@ -617,7 +643,7 @@ impl RawLua {

        let protect = !self.unlikely_memory_error();
        #[cfg(feature = "luau")]
-        let protect = protect || (*self.extra.get()).thread_creation_callback.is_some();
+        let protect = protect || self.thread_event_triggers().on_create;

        let thread_state = if !protect {
            ffi::lua_newthread(state)
@@ -630,6 +656,19 @@ impl RawLua {
        self.set_thread_hook(thread_state, HookKind::Global)?;

        let thread = Thread(self.pop_ref(), thread_state);
+
+        // Exec creation callback for non-Luau (Luau handles this via `userthread_proc`)
+        #[cfg(not(feature = "luau"))]
+        if self.thread_event_triggers().on_create {
+            let extra = self.extra.get();
+            if let Some(ref cb) = (*extra).thread_event_callback
+                && XRc::strong_count(cb) == 1
+            {
+                let cb = cb.clone();
+                cb((*extra).lua(), crate::thread::ThreadEvent::Create(thread.clone()))?;
+            }
+        }
+
        ffi::lua_xpush(self.ref_thread(), thread_state, func.0.index);
        Ok(thread)
    }
@@ -658,13 +697,23 @@ impl RawLua {
    #[cfg(feature = "async")]
    pub(crate) unsafe fn recycle_thread(&self, thread: &mut Thread) {
        let extra = &mut *self.extra.get();
-        if extra.thread_pool.len() < extra.thread_pool.capacity() {
-            if let Some(index) = thread.0.index_count.take() {
-                extra.thread_pool.push(index);
-            }
+        if extra.thread_pool.len() < extra.thread_pool.capacity()
+            && let Some(index) = thread.0.index_count.take()
+        {
+            extra.thread_pool.push(index);
        }
    }

+    #[inline(always)]
+    pub(crate) unsafe fn thread_event_triggers(&self) -> ThreadTriggers {
+        (*self.extra.get()).thread_triggers
+    }
+
+    #[inline(always)]
+    pub(crate) unsafe fn thread_event_callback(&self) -> Option<ThreadEventCallback> {
+        (*self.extra.get()).thread_event_callback.clone()
+    }
+
    /// Pushes a primitive type value onto the Lua stack.
    pub(crate) unsafe fn push_primitive_type<T: LuaType>(&self) -> bool {
        match T::TYPE_ID {
@@ -708,15 +757,28 @@ impl RawLua {
    /// Pushes a value that implements `IntoLua` onto the Lua stack.
    ///
    /// Uses up to 2 stack spaces to push a single value, does not call `checkstack`.
+    #[allow(clippy::missing_safety_doc)]
    #[inline(always)]
-    pub(crate) unsafe fn push(&self, value: impl IntoLua) -> Result<()> {
+    pub unsafe fn push(&self, value: impl IntoLua) -> Result<()> {
        value.push_into_stack(self)
    }

+    /// Pops a value that implements [`FromLua`] from the top of the Lua stack.
+    ///
+    /// Uses up to 1 stack space, does not call `checkstack`.
+    #[allow(clippy::missing_safety_doc)]
+    #[inline(always)]
+    pub unsafe fn pop<R: FromLua>(&self) -> Result<R> {
+        let v = R::from_stack(-1, self)?;
+        ffi::lua_pop(self.state(), 1);
+        Ok(v)
+    }
+
    /// Pushes a `Value` (by reference) onto the Lua stack.
    ///
-    /// Uses 2 stack spaces, does not call `checkstack`.
-    pub(crate) unsafe fn push_value(&self, value: &Value) -> Result<()> {
+    /// Uses up to 2 stack spaces, does not call `checkstack`.
+    #[allow(clippy::missing_safety_doc)]
+    pub unsafe fn push_value(&self, value: &Value) -> Result<()> {
        let state = self.state();
        match value {
            Value::Nil => ffi::lua_pushnil(state),
@@ -750,7 +812,9 @@ impl RawLua {
    /// Pops a value from the Lua stack.
    ///
    /// Uses up to 1 stack spaces, does not call `checkstack`.
-    pub(crate) unsafe fn pop_value(&self) -> Value {
+    #[allow(clippy::missing_safety_doc)]
+    #[inline]
+    pub unsafe fn pop_value(&self) -> Value {
        let value = self.stack_value(-1, None);
        ffi::lua_pop(self.state(), 1);
        value
@@ -768,7 +832,7 @@ impl RawLua {

            ffi::LUA_TLIGHTUSERDATA => Value::LightUserData(LightUserData(ffi::lua_touserdata(state, idx))),

-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            ffi::LUA_TNUMBER => {
                if ffi::lua_isinteger(state, idx) != 0 {
                    Value::Integer(ffi::lua_tointeger(state, idx))
@@ -779,15 +843,22 @@ impl RawLua {

            #[cfg(any(feature = "lua52", feature = "lua51", feature = "luajit", feature = "luau"))]
            ffi::LUA_TNUMBER => {
-                use crate::types::Number;
-
                let n = ffi::lua_tonumber(state, idx);
                match num_traits::cast(n) {
-                    Some(i) if n.to_bits() == (i as Number).to_bits() => Value::Integer(i),
+                    Some(i) if n.to_bits() == (i as crate::types::Number).to_bits() => Value::Integer(i),
                    _ => Value::Number(n),
                }
            }

+            #[cfg(feature = "luau")]
+            ffi::LUA_TINTEGER => {
+                let i = ffi::lua_tointeger64(state, idx, ptr::null_mut());
+                match num_traits::cast(i) {
+                    Some(i) => Value::Integer(i),
+                    _ => Value::Number(i as crate::types::Number),
+                }
+            }
+
            #[cfg(feature = "luau")]
            ffi::LUA_TVECTOR => {
                let v = ffi::lua_tovector(state, idx);
@@ -800,7 +871,7 @@ impl RawLua {

            ffi::LUA_TSTRING => {
                ffi::lua_xpush(state, self.ref_thread(), idx);
-                Value::String(String(self.pop_ref_thread()))
+                Value::String(LuaString(self.pop_ref_thread()))
            }

            ffi::LUA_TTABLE => {
@@ -899,7 +970,7 @@ impl RawLua {
        #[cfg(any(feature = "lua51", feature = "luajit", feature = "luau"))]
        ffi::lua_xpush(self.ref_thread(), state, ExtraData::ERROR_TRACEBACK_IDX);
        // Lua 5.2+ support light C functions that does not require extra allocations
-        #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
        ffi::lua_pushcfunction(state, crate::util::error_traceback);
    }

@@ -925,7 +996,7 @@ impl RawLua {
            // Check if userdata/metatable is already registered
            let type_id = TypeId::of::<T>();
            if let Some(&table_id) = (*self.extra.get()).registered_userdata_t.get(&type_id) {
-                return Ok(table_id as Integer);
+                return Ok(table_id);
            }

            // Create a new metatable from `UserData` definition
@@ -944,7 +1015,7 @@ impl RawLua {
            // Check if userdata/metatable is already registered
            let type_id = TypeId::of::<T>();
            if let Some(&table_id) = (*self.extra.get()).registered_userdata_t.get(&type_id) {
-                return Ok(table_id as Integer);
+                return Ok(table_id);
            }

            // Check if metatable creation is pending or create an empty metatable otherwise
@@ -959,7 +1030,7 @@ impl RawLua {
    unsafe fn make_userdata_with_metatable<T>(
        &self,
        data: UserDataStorage<T>,
-        get_metatable_id: impl FnOnce() -> Result<Integer>,
+        get_metatable_id: impl FnOnce() -> Result<c_int>,
    ) -> Result<AnyUserData> {
        let state = self.state();
        let _sg = StackGuard::new(state);
@@ -969,7 +1040,7 @@ impl RawLua {
        let mt_id = get_metatable_id()?;
        let protect = !self.unlikely_memory_error();
        push_userdata(state, data, protect)?;
-        ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, mt_id);
+        ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, mt_id as _);
        ffi::lua_setmetatable(state, -2);

        // Set empty environment for Lua 5.1
@@ -987,7 +1058,7 @@ impl RawLua {
        Ok(AnyUserData(self.pop_ref()))
    }

-    pub(crate) unsafe fn create_userdata_metatable(&self, registry: RawUserDataRegistry) -> Result<Integer> {
+    pub(crate) unsafe fn create_userdata_metatable(&self, registry: RawUserDataRegistry) -> Result<c_int> {
        let state = self.state();
        let type_id = registry.type_id;

@@ -1003,7 +1074,7 @@ impl RawLua {
        }
        self.register_userdata_metatable(mt_ptr, type_id);

-        Ok(id as Integer)
+        Ok(id)
    }

    pub(crate) unsafe fn push_userdata_metatable(&self, mut registry: RawUserDataRegistry) -> Result<()> {
@@ -1102,7 +1173,7 @@ impl RawLua {
        #[cfg(feature = "luau")]
        if registry.enable_namecall {
            let map: &mut rustc_hash::FxHashMap<_, crate::types::CallbackPtr> =
-                methods_map.get_or_insert_with(Default::default);
+                methods_map.get_or_insert_default();
            for (k, m) in &registry.methods {
                map.insert(k.as_bytes().to_vec(), &**m);
            }
@@ -1195,10 +1266,11 @@ impl RawLua {
            Ok(type_id) => Ok(type_id),
            Err(Error::UserDataTypeMismatch) if ffi::lua_type(state, idx) != ffi::LUA_TUSERDATA => {
                // Report `FromLuaConversionError` instead
-                let idx_type_name = CStr::from_ptr(ffi::luaL_typename(state, idx));
-                let idx_type_name = idx_type_name.to_str().unwrap();
+                let type_name = CStr::from_ptr(ffi::lua_typename(state, ffi::lua_type(state, idx)))
+                    .to_str()
+                    .unwrap_or("unknown");
                let message = format!("expected userdata of type '{}'", short_type_name::<T>());
-                Err(Error::from_lua_conversion(idx_type_name, "userdata", message))
+                Err(Error::from_lua_conversion(type_name, "userdata", message))
            }
            Err(err) => Err(err),
        }
@@ -1279,7 +1351,13 @@ impl RawLua {
    #[cfg(feature = "async")]
    pub(crate) fn create_async_callback(&self, func: AsyncCallback) -> Result<Function> {
        // Ensure that the coroutine library is loaded
-        #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau"))]
+        #[cfg(any(
+            feature = "lua55",
+            feature = "lua54",
+            feature = "lua53",
+            feature = "lua52",
+            feature = "luau"
+        ))]
        unsafe {
            if !(*self.extra.get()).libs.contains(StdLib::COROUTINE) {
                load_std_libs(self.main_state(), StdLib::COROUTINE)?;
@@ -1492,7 +1570,13 @@ unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()>
    #[cfg(feature = "luajit")]
    let _gc_guard = GcGuard::new(state);

-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau"))]
+    #[cfg(any(
+        feature = "lua55",
+        feature = "lua54",
+        feature = "lua53",
+        feature = "lua52",
+        feature = "luau"
+    ))]
    {
        if libs.contains(StdLib::COROUTINE) {
            requiref(state, ffi::LUA_COLIBNAME, ffi::luaopen_coroutine, 1)?;
@@ -1516,7 +1600,7 @@ unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()>
        requiref(state, ffi::LUA_STRLIBNAME, ffi::luaopen_string, 1)?;
    }

-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "luau"))]
    {
        if libs.contains(StdLib::UTF8) {
            requiref(state, ffi::LUA_UTF8LIBNAME, ffi::luaopen_utf8, 1)?;
@@ -1547,6 +1631,11 @@ unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()>
        requiref(state, ffi::LUA_VECLIBNAME, ffi::luaopen_vector, 1)?;
    }

+    #[cfg(feature = "luau")]
+    if libs.contains(StdLib::INTEGER) {
+        requiref(state, ffi::LUA_INTLIBNAME, ffi::luaopen_integer, 1)?;
+    }
+
    if libs.contains(StdLib::MATH) {
        requiref(state, ffi::LUA_MATHLIBNAME, ffi::luaopen_math, 1)?;
    }
@@ -1,11 +1,11 @@
 use std::os::raw::c_int;
-use std::panic::{catch_unwind, AssertUnwindSafe};
+use std::panic::{AssertUnwindSafe, catch_unwind};
 use std::ptr;
 use std::sync::Arc;

 use crate::error::{Error, Result};
 use crate::state::{ExtraData, RawLua};
-use crate::util::{self, get_internal_metatable, WrappedFailure};
+use crate::util::{self, WrappedFailure, get_internal_metatable};

 struct StateGuard<'a>(&'a RawLua, *mut ffi::lua_State);

@@ -1,4 +1,4 @@
-use std::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign};
+use std::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Not};

 /// Flags describing the set of lua standard libraries to load.
 #[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
@@ -6,10 +6,22 @@ pub struct StdLib(u32);

 impl StdLib {
    /// [`coroutine`](https://www.lua.org/manual/5.4/manual.html#6.2) library
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau"))]
+    #[cfg(any(
+        feature = "lua55",
+        feature = "lua54",
+        feature = "lua53",
+        feature = "lua52",
+        feature = "luau"
+    ))]
    #[cfg_attr(
        docsrs,
-        doc(cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luau")))
+        doc(cfg(any(
+            feature = "lua55",
+            feature = "lua54",
+            feature = "lua53",
+            feature = "lua52",
+            feature = "luau"
+        )))
    )]
    pub const COROUTINE: StdLib = StdLib(1);

@@ -28,8 +40,11 @@ impl StdLib {
    pub const STRING: StdLib = StdLib(1 << 4);

    /// [`utf8`](https://www.lua.org/manual/5.4/manual.html#6.5) library
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "luau"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "luau")))
+    )]
    pub const UTF8: StdLib = StdLib(1 << 5);

    /// [`bit`](https://www.lua.org/manual/5.2/manual.html#6.7) library
@@ -58,10 +73,15 @@ impl StdLib {
    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
    pub const VECTOR: StdLib = StdLib(1 << 10);

+    /// [`integer`](https://luau.org/library#integer-library) library
+    #[cfg(any(feature = "luau", doc))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
+    pub const INTEGER: StdLib = StdLib(1 << 11);
+
    /// [`jit`](http://luajit.org/ext_jit.html) library
    #[cfg(any(feature = "luajit", doc))]
    #[cfg_attr(docsrs, doc(cfg(feature = "luajit")))]
-    pub const JIT: StdLib = StdLib(1 << 11);
+    pub const JIT: StdLib = StdLib(1 << 12);

    /// (**unsafe**) [`ffi`](http://luajit.org/ext_ffi.html) library
    #[cfg(any(feature = "luajit", doc))]
@@ -124,3 +144,10 @@ impl BitXorAssign for StdLib {
        *self = StdLib(self.0 ^ rhs.0)
    }
 }
+
+impl Not for StdLib {
+    type Output = Self;
+    fn not(self) -> Self::Output {
+        StdLib(!self.0)
+    }
+}
@@ -1,9 +1,12 @@
-use std::borrow::{Borrow, Cow};
+//! Lua string handling.
+//!
+//! This module provides types for working with Lua strings from Rust.
+
+use std::borrow::Borrow;
 use std::hash::{Hash, Hasher};
 use std::ops::Deref;
 use std::os::raw::{c_int, c_void};
-use std::string::String as StdString;
-use std::{cmp, fmt, slice, str};
+use std::{cmp, fmt, mem, slice, str};

 use crate::error::{Error, Result};
 use crate::state::Lua;
@@ -20,38 +23,41 @@ use {
 /// Handle to an internal Lua string.
 ///
 /// Unlike Rust strings, Lua strings may not be valid UTF-8.
-#[derive(Clone)]
-pub struct String(pub(crate) ValueRef);
+#[derive(Clone, PartialEq)]
+pub struct LuaString(pub(crate) ValueRef);

-impl String {
+impl LuaString {
    /// Get a [`BorrowedStr`] if the Lua string is valid UTF-8.
    ///
+    /// The returned `BorrowedStr` holds a strong reference to the Lua state to guarantee the
+    /// validity of the underlying data.
+    ///
    /// # Examples
    ///
    /// ```
-    /// # use mlua::{Lua, Result, String};
+    /// # use mlua::{Lua, LuaString, Result};
    /// # fn main() -> Result<()> {
    /// # let lua = Lua::new();
    /// let globals = lua.globals();
    ///
-    /// let version: String = globals.get("_VERSION")?;
+    /// let version: LuaString = globals.get("_VERSION")?;
    /// assert!(version.to_str()?.contains("Lua"));
    ///
-    /// let non_utf8: String = lua.load(r#"  "test\255"  "#).eval()?;
+    /// let non_utf8: LuaString = lua.load(r#"  "test\255"  "#).eval()?;
    /// assert!(non_utf8.to_str().is_err());
    /// # Ok(())
    /// # }
    /// ```
    #[inline]
-    pub fn to_str(&self) -> Result<BorrowedStr<'_>> {
+    pub fn to_str(&self) -> Result<BorrowedStr> {
        BorrowedStr::try_from(self)
    }

-    /// Converts this string to a [`StdString`].
+    /// Converts this Lua string to a [`String`].
    ///
    /// Any non-Unicode sequences are replaced with [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD].
    ///
-    /// This method returns [`StdString`] instead of [`Cow<'_, str>`] because lifetime cannot be
+    /// This method returns [`String`] instead of [`Cow<'_, str>`] because lifetime cannot be
    /// bound to a weak Lua object.
    ///
    /// [U+FFFD]: std::char::REPLACEMENT_CHARACTER
@@ -70,11 +76,11 @@ impl String {
    /// # }
    /// ```
    #[inline]
-    pub fn to_string_lossy(&self) -> StdString {
-        StdString::from_utf8_lossy(&self.as_bytes()).into_owned()
+    pub fn to_string_lossy(&self) -> String {
+        String::from_utf8_lossy(&self.as_bytes()).into_owned()
    }

-    /// Returns an object that implements [`Display`] for safely printing a Lua [`String`] that may
+    /// Returns an object that implements [`Display`] for safely printing a [`LuaString`] that may
    /// contain non-Unicode data.
    ///
    /// This may perform lossy conversion.
@@ -86,32 +92,33 @@ impl String {

    /// Get the bytes that make up this string.
    ///
-    /// The returned slice will not contain the terminating null byte, but will contain any null
-    /// bytes embedded into the Lua string.
+    /// The returned `BorrowedStr` holds a strong reference to the Lua state to guarantee the
+    /// validity of the underlying data. The data will not contain the terminating null byte, but
+    /// will contain any null bytes embedded into the Lua string.
    ///
    /// # Examples
    ///
    /// ```
-    /// # use mlua::{Lua, Result, String};
+    /// # use mlua::{Lua, LuaString, Result};
    /// # fn main() -> Result<()> {
    /// # let lua = Lua::new();
-    /// let non_utf8: String = lua.load(r#"  "test\255"  "#).eval()?;
+    /// let non_utf8: LuaString = lua.load(r#"  "test\255"  "#).eval()?;
    /// assert!(non_utf8.to_str().is_err());    // oh no :(
    /// assert_eq!(non_utf8.as_bytes(), &b"test\xff"[..]);
    /// # Ok(())
    /// # }
    /// ```
    #[inline]
-    pub fn as_bytes(&self) -> BorrowedBytes<'_> {
+    pub fn as_bytes(&self) -> BorrowedBytes {
        BorrowedBytes::from(self)
    }

    /// Get the bytes that make up this string, including the trailing null byte.
-    pub fn as_bytes_with_nul(&self) -> BorrowedBytes<'_> {
-        let BorrowedBytes { buf, borrow, _lua } = BorrowedBytes::from(self);
+    pub fn as_bytes_with_nul(&self) -> BorrowedBytes {
+        let BorrowedBytes { buf, vref, _lua } = BorrowedBytes::from(self);
        // Include the trailing null byte (it's always present but excluded by default)
        let buf = unsafe { slice::from_raw_parts((*buf).as_ptr(), (*buf).len() + 1) };
-        BorrowedBytes { buf, borrow, _lua }
+        BorrowedBytes { buf, vref, _lua }
    }

    // Does not return the terminating null byte
@@ -135,18 +142,21 @@ impl String {
        (slice, lua)
    }

-    /// Converts this string to a generic C pointer.
+    /// Converts this Lua string to a generic C pointer.
    ///
    /// There is no way to convert the pointer back to its original value.
    ///
    /// Typically this function is used only for hashing and debug information.
    #[inline]
    pub fn to_pointer(&self) -> *const c_void {
-        self.0.to_pointer()
+        // In Lua < 5.4 (excluding Luau), string pointers are NULL
+        // Use alternative approach
+        let lua = self.0.lua.lock();
+        unsafe { ffi::lua_tostring(lua.ref_thread(), self.0.index) as *const c_void }
    }
 }

-impl fmt::Debug for String {
+impl fmt::Debug for LuaString {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let bytes = self.as_bytes();
        // Check if the string is valid utf8
@@ -162,12 +172,12 @@ impl fmt::Debug for String {

 // Lua strings are basically `&[u8]` slices, so implement `PartialEq` for anything resembling that.
 //
-// This makes our `String` comparable with `Vec<u8>`, `[u8]`, `&str` and `String`.
+// This makes our `LuaString` comparable with `Vec<u8>`, `[u8]`, `&str` and `String`.
 //
 // The only downside is that this disallows a comparison with `Cow<str>`, as that only implements
 // `AsRef<str>`, which collides with this impl. Requiring `AsRef<str>` would fix that, but limit us
 // in other ways.
-impl<T> PartialEq<T> for String
+impl<T> PartialEq<T> for LuaString
 where
    T: AsRef<[u8]> + ?Sized,
 {
@@ -176,43 +186,37 @@ where
    }
 }

-impl PartialEq for String {
-    fn eq(&self, other: &String) -> bool {
-        self.as_bytes() == other.as_bytes()
-    }
-}
+impl Eq for LuaString {}

-impl Eq for String {}
-
-impl<T> PartialOrd<T> for String
+impl<T> PartialOrd<T> for LuaString
 where
    T: AsRef<[u8]> + ?Sized,
 {
    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
-        self.as_bytes().partial_cmp(&other.as_ref())
+        <[u8]>::partial_cmp(&self.as_bytes(), other.as_ref())
    }
 }

-impl PartialOrd for String {
-    fn partial_cmp(&self, other: &String) -> Option<cmp::Ordering> {
+impl PartialOrd for LuaString {
+    fn partial_cmp(&self, other: &LuaString) -> Option<cmp::Ordering> {
        Some(self.cmp(other))
    }
 }

-impl Ord for String {
-    fn cmp(&self, other: &String) -> cmp::Ordering {
+impl Ord for LuaString {
+    fn cmp(&self, other: &LuaString) -> cmp::Ordering {
        self.as_bytes().cmp(&other.as_bytes())
    }
 }

-impl Hash for String {
+impl Hash for LuaString {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.as_bytes().hash(state);
    }
 }

 #[cfg(feature = "serde")]
-impl Serialize for String {
+impl Serialize for LuaString {
    fn serialize<S>(&self, serializer: S) -> StdResult<S::Ok, S::Error>
    where
        S: Serializer,
@@ -224,7 +228,7 @@ impl Serialize for String {
    }
 }

-struct Display<'a>(&'a String);
+struct Display<'a>(&'a LuaString);

 impl fmt::Display for Display<'_> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -234,14 +238,14 @@ impl fmt::Display for Display<'_> {
 }

 /// A borrowed string (`&str`) that holds a strong reference to the Lua state.
-pub struct BorrowedStr<'a> {
+pub struct BorrowedStr {
    // `buf` points to a readonly memory managed by Lua
-    pub(crate) buf: &'a str,
-    pub(crate) borrow: Cow<'a, String>,
+    pub(crate) buf: &'static str,
+    pub(crate) vref: ValueRef,
    pub(crate) _lua: Lua,
 }

-impl Deref for BorrowedStr<'_> {
+impl Deref for BorrowedStr {
    type Target = str;

    #[inline(always)]
@@ -250,33 +254,33 @@ impl Deref for BorrowedStr<'_> {
    }
 }

-impl Borrow<str> for BorrowedStr<'_> {
+impl Borrow<str> for BorrowedStr {
    #[inline(always)]
    fn borrow(&self) -> &str {
        self.buf
    }
 }

-impl AsRef<str> for BorrowedStr<'_> {
+impl AsRef<str> for BorrowedStr {
    #[inline(always)]
    fn as_ref(&self) -> &str {
        self.buf
    }
 }

-impl fmt::Display for BorrowedStr<'_> {
+impl fmt::Display for BorrowedStr {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        self.buf.fmt(f)
    }
 }

-impl fmt::Debug for BorrowedStr<'_> {
+impl fmt::Debug for BorrowedStr {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        self.buf.fmt(f)
    }
 }

-impl<T> PartialEq<T> for BorrowedStr<'_>
+impl<T> PartialEq<T> for BorrowedStr
 where
    T: AsRef<str>,
 {
@@ -285,9 +289,9 @@ where
    }
 }

-impl Eq for BorrowedStr<'_> {}
+impl Eq for BorrowedStr {}

-impl<T> PartialOrd<T> for BorrowedStr<'_>
+impl<T> PartialOrd<T> for BorrowedStr
 where
    T: AsRef<str>,
 {
@@ -296,36 +300,33 @@ where
    }
 }

-impl Ord for BorrowedStr<'_> {
+impl Ord for BorrowedStr {
    fn cmp(&self, other: &Self) -> cmp::Ordering {
        self.buf.cmp(other.buf)
    }
 }

-impl<'a> TryFrom<&'a String> for BorrowedStr<'a> {
+impl TryFrom<&LuaString> for BorrowedStr {
    type Error = Error;

    #[inline]
-    fn try_from(value: &'a String) -> Result<Self> {
-        let BorrowedBytes { buf, borrow, _lua } = BorrowedBytes::from(value);
-        let buf = str::from_utf8(buf).map_err(|e| Error::FromLuaConversionError {
-            from: "string",
-            to: "&str".to_string(),
-            message: Some(e.to_string()),
-        })?;
-        Ok(Self { buf, borrow, _lua })
+    fn try_from(value: &LuaString) -> Result<Self> {
+        let BorrowedBytes { buf, vref, _lua } = BorrowedBytes::from(value);
+        let buf =
+            str::from_utf8(buf).map_err(|e| Error::from_lua_conversion("string", "&str", e.to_string()))?;
+        Ok(Self { buf, vref, _lua })
    }
 }

 /// A borrowed byte slice (`&[u8]`) that holds a strong reference to the Lua state.
-pub struct BorrowedBytes<'a> {
+pub struct BorrowedBytes {
    // `buf` points to a readonly memory managed by Lua
-    pub(crate) buf: &'a [u8],
-    pub(crate) borrow: Cow<'a, String>,
+    pub(crate) buf: &'static [u8],
+    pub(crate) vref: ValueRef,
    pub(crate) _lua: Lua,
 }

-impl Deref for BorrowedBytes<'_> {
+impl Deref for BorrowedBytes {
    type Target = [u8];

    #[inline(always)]
@@ -334,27 +335,27 @@ impl Deref for BorrowedBytes<'_> {
    }
 }

-impl Borrow<[u8]> for BorrowedBytes<'_> {
+impl Borrow<[u8]> for BorrowedBytes {
    #[inline(always)]
    fn borrow(&self) -> &[u8] {
        self.buf
    }
 }

-impl AsRef<[u8]> for BorrowedBytes<'_> {
+impl AsRef<[u8]> for BorrowedBytes {
    #[inline(always)]
    fn as_ref(&self) -> &[u8] {
        self.buf
    }
 }

-impl fmt::Debug for BorrowedBytes<'_> {
+impl fmt::Debug for BorrowedBytes {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        self.buf.fmt(f)
    }
 }

-impl<T> PartialEq<T> for BorrowedBytes<'_>
+impl<T> PartialEq<T> for BorrowedBytes
 where
    T: AsRef<[u8]>,
 {
@@ -363,9 +364,9 @@ where
    }
 }

-impl Eq for BorrowedBytes<'_> {}
+impl Eq for BorrowedBytes {}

-impl<T> PartialOrd<T> for BorrowedBytes<'_>
+impl<T> PartialOrd<T> for BorrowedBytes
 where
    T: AsRef<[u8]>,
 {
@@ -374,13 +375,13 @@ where
    }
 }

-impl Ord for BorrowedBytes<'_> {
+impl Ord for BorrowedBytes {
    fn cmp(&self, other: &Self) -> cmp::Ordering {
        self.buf.cmp(other.buf)
    }
 }

-impl<'a> IntoIterator for &'a BorrowedBytes<'_> {
+impl<'a> IntoIterator for &'a BorrowedBytes {
    type Item = &'a u8;
    type IntoIter = slice::Iter<'a, u8>;

@@ -389,18 +390,20 @@ impl<'a> IntoIterator for &'a BorrowedBytes<'_> {
    }
 }

-impl<'a> From<&'a String> for BorrowedBytes<'a> {
+impl From<&LuaString> for BorrowedBytes {
    #[inline]
-    fn from(value: &'a String) -> Self {
+    fn from(value: &LuaString) -> Self {
        let (buf, _lua) = unsafe { value.to_slice() };
-        let borrow = Cow::Borrowed(value);
-        Self { buf, borrow, _lua }
+        let vref = value.0.clone();
+        // SAFETY: The `buf` is valid for the lifetime of the Lua state and occupied slot index
+        let buf = unsafe { mem::transmute::<&[u8], &'static [u8]>(buf) };
+        Self { buf, vref, _lua }
    }
 }

 struct WrappedString<T: AsRef<[u8]>>(T);

-impl String {
+impl LuaString {
    /// Wraps bytes, returning an opaque type that implements [`IntoLua`] trait.
    ///
    /// This function uses [`Lua::create_string`] under the hood.
@@ -415,7 +418,7 @@ impl<T: AsRef<[u8]>> IntoLua for WrappedString<T> {
    }
 }

-impl LuaType for String {
+impl LuaType for LuaString {
    const TYPE_ID: c_int = ffi::LUA_TSTRING;
 }

@@ -424,9 +427,9 @@ mod assertions {
    use super::*;

    #[cfg(not(feature = "send"))]
-    static_assertions::assert_not_impl_any!(String: Send);
+    static_assertions::assert_not_impl_any!(LuaString: Send);
    #[cfg(feature = "send")]
-    static_assertions::assert_impl_all!(String: Send, Sync);
+    static_assertions::assert_impl_all!(LuaString: Send, Sync);
    #[cfg(feature = "send")]
    static_assertions::assert_impl_all!(BorrowedBytes: Send, Sync);
    #[cfg(feature = "send")]
@@ -1,15 +1,167 @@
+//! Lua table handling.
+//!
+//! Tables are Lua's primary data structure, used for arrays, dictionaries, objects, modules,
+//! and more. This module provides types for creating and manipulating Lua tables from Rust.
+//!
+//! # Basic Operations
+//!
+//! Tables support key-value access similar to Rust's `HashMap`:
+//!
+//! ```
+//! # use mlua::{Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//! let table = lua.create_table()?;
+//!
+//! // Set and get values
+//! table.set("key", "value")?;
+//! let value: String = table.get("key")?;
+//! assert_eq!(value, "value");
+//!
+//! // Keys and values can be any Lua-compatible type
+//! table.set(1, "first")?;
+//! table.set("nested", lua.create_table()?)?;
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! # Array Operations
+//!
+//! Tables can be used as arrays with 1-based indexing:
+//!
+//! ```
+//! # use mlua::{Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//! let array = lua.create_table()?;
+//!
+//! // Push values to the end (like Vec::push)
+//! array.push("first")?;
+//! array.push("second")?;
+//! array.push("third")?;
+//!
+//! // Pop from the end
+//! let last: String = array.pop()?;
+//! assert_eq!(last, "third");
+//!
+//! // Get length
+//! assert_eq!(array.raw_len(), 2);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! # Iteration
+//!
+//! Iterate over all key-value pairs with [`Table::pairs`]:
+//!
+//! ```
+//! # use mlua::{Lua, Result, Value};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//! let table = lua.create_table()?;
+//! table.set("a", 1)?;
+//! table.set("b", 2)?;
+//!
+//! for pair in table.pairs::<String, i32>() {
+//!     let (key, value) = pair?;
+//!     println!("{key} = {value}");
+//! }
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! For array portions, use [`Table::sequence_values`]:
+//!
+//! ```
+//! # use mlua::{Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//! let array = lua.create_sequence_from(["a", "b", "c"])?;
+//!
+//! for value in array.sequence_values::<String>() {
+//!     println!("{}", value?);
+//! }
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! # Raw vs Normal Access
+//!
+//! Methods prefixed with `raw_` (like [`Table::raw_get`], [`Table::raw_set`]) bypass
+//! metamethods, directly accessing the table's contents. Normal methods may trigger
+//! `__index`, `__newindex`, and other metamethods:
+//!
+//! ```
+//! # use mlua::{Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//!
+//! // raw_set bypasses __newindex metamethod
+//! let t = lua.create_table()?;
+//! t.raw_set("key", "value")?;
+//!
+//! // raw_get bypasses __index metamethod
+//! let v: String = t.raw_get("key")?;
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! # Metatables
+//!
+//! Tables can have metatables that customize their behavior:
+//!
+//! ```
+//! # use mlua::{Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//!
+//! let table = lua.create_table()?;
+//! let metatable = lua.create_table()?;
+//!
+//! // Set a default value via __index
+//! metatable.set("__index", lua.create_function(|_, _: ()| Ok("default"))?)?;
+//! table.set_metatable(Some(metatable))?;
+//!
+//! // Accessing missing keys returns "default"
+//! let value: String = table.get("missing")?;
+//! assert_eq!(value, "default");
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! # Global Table
+//!
+//! The Lua global environment is itself a table, accessible via [`Lua::globals`]:
+//!
+//! ```
+//! # use mlua::{Lua, Result};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//! let globals = lua.globals();
+//!
+//! // Set a global variable
+//! globals.set("my_var", 42)?;
+//!
+//! // Now accessible from Lua code
+//! let result: i32 = lua.load("my_var + 8").eval()?;
+//! assert_eq!(result, 50);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [`Lua::globals`]: crate::Lua::globals
+
 use std::collections::HashSet;
 use std::fmt;
 use std::marker::PhantomData;
 use std::os::raw::c_void;
-use std::string::String as StdString;

 use crate::error::{Error, Result};
 use crate::function::Function;
 use crate::state::{LuaGuard, RawLua, WeakLua};
 use crate::traits::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, ObjectLike};
 use crate::types::{Integer, ValueRef};
-use crate::util::{assert_stack, check_stack, get_metatable_ptr, StackGuard};
+use crate::util::{StackGuard, assert_stack, check_stack, get_metatable_ptr};
 use crate::value::{Nil, Value};

 #[cfg(feature = "async")]
@@ -226,15 +378,15 @@ impl Table {
        // Compare using `__eq` metamethod if exists
        // First, check the self for the metamethod.
        // If self does not define it, then check the other table.
-        if let Some(mt) = self.metatable() {
-            if mt.contains_key("__eq")? {
-                return mt.get::<Function>("__eq")?.call((self, other));
-            }
+        if let Some(mt) = self.metatable()
+            && let Some(eq_func) = mt.get::<Option<Function>>("__eq")?
+        {
+            return eq_func.call((self, other));
        }
-        if let Some(mt) = other.metatable() {
-            if mt.contains_key("__eq")? {
-                return mt.get::<Function>("__eq")?.call((self, other));
-            }
+        if let Some(mt) = other.metatable()
+            && let Some(eq_func) = mt.get::<Option<Function>>("__eq")?
+        {
+            return eq_func.call((self, other));
        }

        Ok(false)
@@ -626,10 +778,8 @@ impl Table {
            ffi::lua_pushnil(state);
            while ffi::lua_next(state, -2) != 0 {
                let k = K::from_stack(-2, &lua)?;
-                let v = V::from_stack(-1, &lua)?;
+                let v = lua.pop::<V>()?;
                f(k, v)?;
-                // Keep key for next iteration
-                ffi::lua_pop(state, 1);
            }
        }
        Ok(())
@@ -702,8 +852,7 @@ impl Table {
                if len.is_none() && t == ffi::LUA_TNIL {
                    break;
                }
-                f(V::from_stack(-1, &lua)?)?;
-                ffi::lua_pop(state, 1);
+                f(lua.pop::<V>()?)?;
            }
        }
        Ok(())
@@ -1008,7 +1157,7 @@ impl ObjectLike for Table {
    }

    #[inline]
-    fn to_string(&self) -> Result<StdString> {
+    fn to_string(&self) -> Result<String> {
        Value::Table(Table(self.0.clone())).to_string()
    }

@@ -1070,7 +1219,7 @@ impl Serialize for SerializableTable<'_> {
    where
        S: Serializer,
    {
-        use crate::serde::de::{check_value_for_skip, MapPairs, RecursionGuard};
+        use crate::serde::de::{MapPairs, RecursionGuard, check_value_for_skip};
        use crate::value::SerializableValue;

        let convert_result = |res: Result<()>, serialize_err: Option<S::Error>| match res {
@@ -1098,7 +1247,7 @@ impl Serialize for SerializableTable<'_> {
                seq.serialize_element(&SerializableValue::new(&value, options, Some(visited)))
                    .map_err(|err| {
                        serialize_err = Some(err);
-                        Error::SerializeError(StdString::new())
+                        Error::SerializeError(String::new())
                    })
            });
            convert_result(res, serialize_err)?;
@@ -1123,7 +1272,7 @@ impl Serialize for SerializableTable<'_> {
            )
            .map_err(|err| {
                serialize_err = Some(err);
-                Error::SerializeError(StdString::new())
+                Error::SerializeError(String::new())
            })
        };

@@ -1,3 +1,40 @@
+//! Lua thread (coroutine) handling.
+//!
+//! This module provides types for creating and working with Lua coroutines from Rust.
+//! Coroutines allow cooperative multitasking within a single Lua state by suspending and
+//! resuming execution at well-defined yield points.
+//!
+//! # Basic Usage
+//!
+//! Threads are created via [`Lua::create_thread`] and driven by calling [`Thread::resume`]:
+//!
+//! ```rust
+//! # use mlua::{Lua, Result, Thread};
+//! # fn main() -> Result<()> {
+//! let lua = Lua::new();
+//! let thread: Thread = lua.load(r#"
+//!     coroutine.create(function(a, b)
+//!         coroutine.yield(a + b)
+//!         return a * b
+//!     end)
+//! "#).eval()?;
+//!
+//! assert_eq!(thread.resume::<i32>((3, 4))?, 7);
+//! assert_eq!(thread.resume::<i32>(())?,    12);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! # Async Support
+//!
+//! When the `async` feature is enabled, a [`Thread`] can be converted into an [`AsyncThread`]
+//! via [`Thread::into_async`], which implements both [`Future`] and [`Stream`].
+//! This integrates Lua coroutines naturally with Rust async runtimes such as Tokio.
+//!
+//! [`Lua::create_thread`]: crate::Lua::create_thread
+//! [`Future`]: std::future::Future
+//! [`Stream`]: futures_util::stream::Stream
+
 use std::fmt;
 use std::os::raw::{c_int, c_void};

@@ -5,8 +42,8 @@ use crate::error::{Error, Result};
 use crate::function::Function;
 use crate::state::RawLua;
 use crate::traits::{FromLuaMulti, IntoLuaMulti};
-use crate::types::{LuaType, ValueRef};
-use crate::util::{check_stack, error_traceback_thread, pop_error, StackGuard};
+use crate::types::{LuaType, ValueRef, XRc};
+use crate::util::{StackGuard, check_stack, error_traceback_thread, pop_error};

 #[cfg(not(feature = "luau"))]
 use crate::{
@@ -26,6 +63,85 @@ use {
    },
 };

+/// Controls which thread lifecycle events trigger the callback.
+#[derive(Clone, Copy, Debug, Default)]
+#[non_exhaustive]
+pub struct ThreadTriggers {
+    /// Trigger the callback when a new thread is created.
+    pub on_create: bool,
+    /// Trigger the callback before a thread is resumed (via [`Thread::resume`]).
+    pub on_resume: bool,
+    /// Trigger the callback after a thread yields.
+    pub on_yield: bool,
+}
+
+impl ThreadTriggers {
+    /// An instance of [`ThreadTriggers`] with `on_create` trigger set.
+    pub const ON_CREATE: Self = Self::new().on_create();
+
+    /// An instance of [`ThreadTriggers`] with `on_resume` trigger set.
+    pub const ON_RESUME: Self = Self::new().on_resume();
+
+    /// An instance of [`ThreadTriggers`] with `on_yield` trigger set.
+    pub const ON_YIELD: Self = Self::new().on_yield();
+
+    /// Returns a new instance of `ThreadTriggers` with all triggers disabled.
+    pub const fn new() -> Self {
+        Self {
+            on_create: false,
+            on_resume: false,
+            on_yield: false,
+        }
+    }
+
+    /// Returns an instance of `ThreadTriggers` with `on_create` trigger set.
+    pub const fn on_create(mut self) -> Self {
+        self.on_create = true;
+        self
+    }
+
+    /// Returns an instance of `ThreadTriggers` with `on_resume` trigger set.
+    pub const fn on_resume(mut self) -> Self {
+        self.on_resume = true;
+        self
+    }
+
+    /// Returns an instance of `ThreadTriggers` with `on_yield` trigger set.
+    pub const fn on_yield(mut self) -> Self {
+        self.on_yield = true;
+        self
+    }
+}
+
+impl std::ops::BitOr for ThreadTriggers {
+    type Output = Self;
+
+    fn bitor(mut self, rhs: Self) -> Self::Output {
+        self.on_create |= rhs.on_create;
+        self.on_resume |= rhs.on_resume;
+        self.on_yield |= rhs.on_yield;
+        self
+    }
+}
+
+impl std::ops::BitOrAssign for ThreadTriggers {
+    fn bitor_assign(&mut self, rhs: Self) {
+        *self = *self | rhs;
+    }
+}
+
+/// Represents a thread (coroutine) event.
+#[derive(Debug, Clone)]
+#[non_exhaustive]
+pub enum ThreadEvent {
+    /// A new thread was created.
+    Create(Thread),
+    /// A thread is about to be resumed via [`Thread::resume`].
+    Resume(Thread),
+    /// A thread has just yielded.
+    Yield(Thread),
+}
+
 /// Status of a Lua thread (coroutine).
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum ThreadStatus {
@@ -61,7 +177,6 @@ impl ThreadStatusInner {
        matches!(self, ThreadStatusInner::New(_) | ThreadStatusInner::Yielded(_))
    }

-    #[cfg(feature = "async")]
    #[inline(always)]
    fn is_yielded(self) -> bool {
        matches!(self, ThreadStatusInner::Yielded(_))
@@ -69,7 +184,7 @@ impl ThreadStatusInner {
 }

 /// Handle to an internal Lua thread (coroutine).
-#[derive(Clone)]
+#[derive(Clone, PartialEq)]
 pub struct Thread(pub(crate) ValueRef, pub(crate) *mut ffi::lua_State);

 #[cfg(feature = "send")]
@@ -92,7 +207,6 @@ pub struct AsyncThread<R> {

 impl Thread {
    /// Returns reference to the Lua state that this thread is associated with.
-    #[doc(hidden)]
    #[inline(always)]
    pub fn state(&self) -> *mut ffi::lua_State {
        self.1
@@ -157,6 +271,14 @@ impl Thread {
        unsafe {
            let _sg = StackGuard::new(state);

+            // Exec thread resume callback
+            if lua.thread_event_triggers().on_resume
+                && let Some(cb) = lua.thread_event_callback()
+                && XRc::strong_count(&cb) <= 2
+            {
+                cb(lua.lua(), ThreadEvent::Resume(self.clone()))?;
+            }
+
            let nargs = args.push_into_stack_multi(&lua)?;
            if nargs > 0 {
                check_stack(thread_state, nargs)?;
@@ -165,7 +287,17 @@ impl Thread {
            }

            let _thread_sg = StackGuard::with_top(thread_state, 0);
-            let (_, nresults) = self.resume_inner(&lua, pushed_nargs)?;
+            let (status, nresults) = self.resume_inner(&lua, pushed_nargs)?;
+
+            // Exec thread yield callback
+            if lua.thread_event_triggers().on_yield
+                && status.is_yielded()
+                && let Some(cb) = lua.thread_event_callback()
+                && XRc::strong_count(&cb) <= 2
+            {
+                cb(lua.lua(), ThreadEvent::Yield(self.clone()))?;
+            }
+
            check_stack(state, nresults + 1)?;
            ffi::lua_xmove(thread_state, state, nresults);

@@ -193,12 +325,30 @@ impl Thread {
        unsafe {
            let _sg = StackGuard::new(state);

+            // Exec thread resume callback
+            if lua.thread_event_triggers().on_resume
+                && let Some(cb) = lua.thread_event_callback()
+                && XRc::strong_count(&cb) <= 2
+            {
+                cb(lua.lua(), ThreadEvent::Resume(self.clone()))?;
+            }
+
            check_stack(state, 1)?;
            error.push_into_stack(&lua)?;
            ffi::lua_xmove(state, thread_state, 1);

            let _thread_sg = StackGuard::with_top(thread_state, 0);
-            let (_, nresults) = self.resume_inner(&lua, ffi::LUA_RESUMEERROR)?;
+            let (status, nresults) = self.resume_inner(&lua, ffi::LUA_RESUMEERROR)?;
+
+            // Exec thread yield callback
+            if lua.thread_event_triggers().on_yield
+                && status.is_yielded()
+                && let Some(cb) = lua.thread_event_callback()
+                && XRc::strong_count(&cb) <= 2
+            {
+                cb(lua.lua(), ThreadEvent::Yield(self.clone()))?;
+            }
+
            check_stack(state, nresults + 1)?;
            ffi::lua_xmove(thread_state, state, nresults);

@@ -259,6 +409,31 @@ impl Thread {
        }
    }

+    /// Returns `true` if this thread is resumable (meaning it can be resumed by calling
+    /// [`Thread::resume`]).
+    #[inline(always)]
+    pub fn is_resumable(&self) -> bool {
+        self.status() == ThreadStatus::Resumable
+    }
+
+    /// Returns `true` if this thread is currently running.
+    #[inline(always)]
+    pub fn is_running(&self) -> bool {
+        self.status() == ThreadStatus::Running
+    }
+
+    /// Returns `true` if this thread has finished executing.
+    #[inline(always)]
+    pub fn is_finished(&self) -> bool {
+        self.status() == ThreadStatus::Finished
+    }
+
+    /// Returns `true` if this thread has raised a Lua error during execution.
+    #[inline(always)]
+    pub fn is_error(&self) -> bool {
+        self.status() == ThreadStatus::Error
+    }
+
    /// Sets a hook function that will periodically be called as Lua code executes.
    ///
    /// This function is similar or [`Lua::set_hook`] except that it sets for the thread.
@@ -295,7 +470,7 @@ impl Thread {
    /// Resets a thread
    ///
    /// In [Lua 5.4]: cleans its call stack and closes all pending to-be-closed variables.
-    /// Returns a error in case of either the original error that stopped the thread or errors
+    /// Returns an error in case of either the original error that stopped the thread or errors
    /// in closing methods.
    ///
    /// In Luau: resets to the initial state of a newly created Lua thread.
@@ -336,22 +511,22 @@ impl Thread {
            }
            ThreadStatusInner::Running => Err(Error::runtime("cannot reset a running thread")),
            ThreadStatusInner::Finished => Ok(()),
-            #[cfg(not(any(feature = "lua54", feature = "luau")))]
+            #[cfg(not(any(feature = "lua55", feature = "lua54", feature = "luau")))]
            ThreadStatusInner::Yielded(_) | ThreadStatusInner::Error => {
                Err(Error::runtime("cannot reset non-finished thread"))
            }
-            #[cfg(any(feature = "lua54", feature = "luau"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "luau"))]
            ThreadStatusInner::Yielded(_) | ThreadStatusInner::Error => {
                let thread_state = self.state();

                #[cfg(all(feature = "lua54", not(feature = "vendored")))]
                let status = ffi::lua_resetthread(thread_state);
-                #[cfg(all(feature = "lua54", feature = "vendored"))]
+                #[cfg(any(feature = "lua55", all(feature = "lua54", feature = "vendored")))]
                let status = {
                    let lua = self.0.lua.lock();
                    ffi::lua_closethread(thread_state, lua.state())
                };
-                #[cfg(feature = "lua54")]
+                #[cfg(any(feature = "lua55", feature = "lua54"))]
                if status != ffi::LUA_OK {
                    return Err(pop_error(thread_state, status));
                }
@@ -449,6 +624,8 @@ impl Thread {
    /// Please note that Luau links environment table with chunk when loading it into Lua state.
    /// Therefore you need to load chunks into a thread to link with the thread environment.
    ///
+    /// [`Lua::sandbox`]: crate::Lua::sandbox
+    ///
    /// # Examples
    ///
    /// ```
@@ -502,12 +679,6 @@ impl fmt::Debug for Thread {
    }
 }

-impl PartialEq for Thread {
-    fn eq(&self, other: &Self) -> bool {
-        self.0 == other.0
-    }
-}
-
 impl LuaType for Thread {
    const TYPE_ID: c_int = ffi::LUA_TTHREAD;
 }
@@ -523,6 +694,7 @@ impl<R> AsyncThread<R> {
 #[cfg(feature = "async")]
 impl<R> Drop for AsyncThread<R> {
    fn drop(&mut self) {
+        #[allow(clippy::collapsible_if)]
        if self.recycle {
            if let Some(lua) = self.thread.0.lua.try_lock() {
                unsafe {
@@ -564,9 +736,25 @@ impl<R: FromLuaMulti> Stream for AsyncThread<R> {
            let _thread_sg = StackGuard::with_top(thread_state, 0);
            let _wg = WakerGuard::new(&lua, cx.waker());

+            // Exec thread resume callback
+            if lua.thread_event_triggers().on_resume
+                && let Some(cb) = lua.thread_event_callback()
+                && XRc::strong_count(&cb) <= 2
+            {
+                cb(lua.lua(), ThreadEvent::Resume(self.thread.clone()))?;
+            }
+
            let (status, nresults) = (self.thread).resume_inner(&lua, nargs)?;

            if status.is_yielded() {
+                // Exec thread yield callback
+                if lua.thread_event_triggers().on_yield
+                    && let Some(cb) = lua.thread_event_callback()
+                    && XRc::strong_count(&cb) <= 2
+                {
+                    cb(lua.lua(), ThreadEvent::Yield(self.thread.clone()))?;
+                }
+
                if nresults == 1 && is_poll_pending(thread_state) {
                    return Poll::Pending;
                }
@@ -600,9 +788,25 @@ impl<R: FromLuaMulti> Future for AsyncThread<R> {
            let _thread_sg = StackGuard::with_top(thread_state, 0);
            let _wg = WakerGuard::new(&lua, cx.waker());

+            // Exec thread resume callback
+            if lua.thread_event_triggers().on_resume
+                && let Some(cb) = lua.thread_event_callback()
+                && XRc::strong_count(&cb) <= 2
+            {
+                cb(lua.lua(), ThreadEvent::Resume(self.thread.clone()))?;
+            }
+
            let (status, nresults) = self.thread.resume_inner(&lua, nargs)?;

            if status.is_yielded() {
+                // Exec thread yield callback
+                if lua.thread_event_triggers().on_yield
+                    && let Some(cb) = lua.thread_event_callback()
+                    && XRc::strong_count(&cb) <= 2
+                {
+                    cb(lua.lua(), ThreadEvent::Yield(self.thread.clone()))?;
+                }
+
                if !(nresults == 1 && is_poll_pending(thread_state)) {
                    // Ignore values returned via yield()
                    cx.waker().wake_by_ref();
@@ -1,17 +1,20 @@
+//! Core conversion and extension traits.
+//!
+//! This module provides the fundamental traits for converting values between Rust and Lua,
+//! and for defining native Lua callable functions.
+
 use std::os::raw::c_int;
-use std::string::String as StdString;
 use std::sync::Arc;

 use crate::error::{Error, Result};
 use crate::multi::MultiValue;
 use crate::private::Sealed;
 use crate::state::{Lua, RawLua, WeakLua};
-use crate::types::MaybeSend;
 use crate::util::{check_stack, parse_lookup_path, short_type_name};
 use crate::value::Value;

 #[cfg(feature = "async")]
-use {crate::function::AsyncCallFuture, std::future::Future};
+use crate::function::AsyncCallFuture;

 /// Trait for types convertible to [`Value`].
 pub trait IntoLua: Sized {
@@ -236,7 +239,7 @@ pub trait ObjectLike: Sealed {
    /// Converts the object to a string in a human-readable format.
    ///
    /// This might invoke the `__tostring` metamethod.
-    fn to_string(&self) -> Result<StdString>;
+    fn to_string(&self) -> Result<String>;

    /// Converts the object to a Lua value.
    fn to_value(&self) -> Value;
@@ -246,100 +249,9 @@ pub trait ObjectLike: Sealed {
    fn weak_lua(&self) -> &WeakLua;
 }

-/// A trait for types that can be used as Lua functions.
-pub trait LuaNativeFn<A: FromLuaMulti> {
-    type Output: IntoLuaMulti;
-
-    fn call(&self, args: A) -> Self::Output;
-}
-
-/// A trait for types with mutable state that can be used as Lua functions.
-pub trait LuaNativeFnMut<A: FromLuaMulti> {
-    type Output: IntoLuaMulti;
-
-    fn call(&mut self, args: A) -> Self::Output;
-}
-
-/// A trait for types that returns a future and can be used as Lua functions.
-#[cfg(feature = "async")]
-pub trait LuaNativeAsyncFn<A: FromLuaMulti> {
-    type Output: IntoLuaMulti;
-
-    fn call(&self, args: A) -> impl Future<Output = Self::Output> + MaybeSend + 'static;
-}
-
-macro_rules! impl_lua_native_fn {
-    ($($A:ident),*) => {
-        impl<FN, $($A,)* R> LuaNativeFn<($($A,)*)> for FN
-        where
-            FN: Fn($($A,)*) -> R + MaybeSend + 'static,
-            ($($A,)*): FromLuaMulti,
-            R: IntoLuaMulti,
-        {
-            type Output = R;
-
-            #[allow(non_snake_case)]
-            fn call(&self, args: ($($A,)*)) -> Self::Output {
-                let ($($A,)*) = args;
-                self($($A,)*)
-            }
-        }
-
-        impl<FN, $($A,)* R> LuaNativeFnMut<($($A,)*)> for FN
-        where
-            FN: FnMut($($A,)*) -> R + MaybeSend + 'static,
-            ($($A,)*): FromLuaMulti,
-            R: IntoLuaMulti,
-        {
-            type Output = R;
-
-            #[allow(non_snake_case)]
-            fn call(&mut self, args: ($($A,)*)) -> Self::Output {
-                let ($($A,)*) = args;
-                self($($A,)*)
-            }
-        }
-
-        #[cfg(feature = "async")]
-        impl<FN, $($A,)* Fut, R> LuaNativeAsyncFn<($($A,)*)> for FN
-        where
-            FN: Fn($($A,)*) -> Fut + MaybeSend + 'static,
-            ($($A,)*): FromLuaMulti,
-            Fut: Future<Output = R> + MaybeSend + 'static,
-            R: IntoLuaMulti,
-        {
-            type Output = R;
-
-            #[allow(non_snake_case)]
-            fn call(&self, args: ($($A,)*)) -> impl Future<Output = Self::Output> + MaybeSend + 'static {
-                let ($($A,)*) = args;
-                self($($A,)*)
-            }
-        }
-    };
-}
-
-impl_lua_native_fn!();
-impl_lua_native_fn!(A);
-impl_lua_native_fn!(A, B);
-impl_lua_native_fn!(A, B, C);
-impl_lua_native_fn!(A, B, C, D);
-impl_lua_native_fn!(A, B, C, D, E);
-impl_lua_native_fn!(A, B, C, D, E, F);
-impl_lua_native_fn!(A, B, C, D, E, F, G);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M, N);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O);
-impl_lua_native_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P);
-
 pub(crate) trait ShortTypeName {
    #[inline(always)]
-    fn type_name() -> StdString {
+    fn type_name() -> String {
        short_type_name::<Self>()
    }
 }
@@ -96,22 +96,18 @@ pub(crate) type InterruptCallback = XRc<dyn Fn(&Lua) -> Result<VmState> + Send>;
 #[cfg(all(not(feature = "send"), feature = "luau"))]
 pub(crate) type InterruptCallback = XRc<dyn Fn(&Lua) -> Result<VmState>>;

-#[cfg(all(feature = "send", feature = "luau"))]
-pub(crate) type ThreadCreationCallback = XRc<dyn Fn(&Lua, crate::Thread) -> Result<()> + Send>;
+#[cfg(feature = "send")]
+pub(crate) type ThreadEventCallback = XRc<dyn Fn(&Lua, crate::thread::ThreadEvent) -> Result<()> + Send>;

-#[cfg(all(not(feature = "send"), feature = "luau"))]
-pub(crate) type ThreadCreationCallback = XRc<dyn Fn(&Lua, crate::Thread) -> Result<()>>;
+#[cfg(not(feature = "send"))]
+pub(crate) type ThreadEventCallback = XRc<dyn Fn(&Lua, crate::thread::ThreadEvent) -> Result<()>>;

-#[cfg(all(feature = "send", feature = "luau"))]
-pub(crate) type ThreadCollectionCallback = XRc<dyn Fn(crate::LightUserData) + Send>;
-
-#[cfg(all(not(feature = "send"), feature = "luau"))]
-pub(crate) type ThreadCollectionCallback = XRc<dyn Fn(crate::LightUserData)>;
-
-#[cfg(all(feature = "send", feature = "lua54"))]
+#[cfg(feature = "send")]
+#[cfg(any(feature = "lua55", feature = "lua54"))]
 pub(crate) type WarnCallback = XRc<dyn Fn(&Lua, &str, bool) -> Result<()> + Send>;

-#[cfg(all(not(feature = "send"), feature = "lua54"))]
+#[cfg(not(feature = "send"))]
+#[cfg(any(feature = "lua55", feature = "lua54"))]
 pub(crate) type WarnCallback = XRc<dyn Fn(&Lua, &str, bool) -> Result<()>>;

 /// A trait that adds `Send` requirement if `send` feature is enabled.
@@ -126,6 +122,18 @@ pub trait MaybeSend {}
 #[cfg(not(feature = "send"))]
 impl<T> MaybeSend for T {}

+/// A trait that adds `Sync` requirement if `send` feature is enabled.
+#[cfg(feature = "send")]
+pub trait MaybeSync: Sync {}
+#[cfg(feature = "send")]
+impl<T: Sync> MaybeSync for T {}
+
+/// A trait that adds `Sync` requirement if `send` feature is enabled.
+#[cfg(not(feature = "send"))]
+pub trait MaybeSync {}
+#[cfg(not(feature = "send"))]
+impl<T> MaybeSync for T {}
+
 pub(crate) struct DestructedUserdata;

 pub(crate) trait LuaType {
@@ -69,7 +69,7 @@ mod inner {

        #[inline(always)]
        fn deref(&self) -> &Self::Target {
-            &self.0 .0
+            &self.0.0
        }
    }
 }
@@ -55,10 +55,10 @@ impl Drop for ValueRef {
        if let Some(ValueRefIndex(index)) = self.index_count.take() {
            // It's guaranteed that the inner value returns exactly once.
            // This means in particular that the value is not dropped.
-            if XRc::into_inner(index).is_some() {
-                if let Some(lua) = self.lua.try_lock() {
-                    unsafe { lua.drop_ref(self) };
-                }
+            if XRc::into_inner(index).is_some()
+                && let Some(lua) = self.lua.try_lock()
+            {
+                unsafe { lua.drop_ref(self) }
            }
        }
    }
@@ -1,18 +1,22 @@
+//! Lua userdata handling.
+//!
+//! This module provides types for creating and working with Lua userdata from Rust.
+
 use std::any::TypeId;
 use std::ffi::CStr;
 use std::fmt;
 use std::hash::Hash;
 use std::os::raw::{c_char, c_void};
-use std::string::String as StdString;

+use crate::Either;
 use crate::error::{Error, Result};
 use crate::function::Function;
 use crate::state::Lua;
-use crate::string::String;
+use crate::string::LuaString;
 use crate::table::{Table, TablePairs};
 use crate::traits::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti};
-use crate::types::{MaybeSend, ValueRef};
-use crate::util::{check_stack, get_userdata, push_string, short_type_name, take_userdata, StackGuard};
+use crate::types::{MaybeSend, MaybeSync, ValueRef};
+use crate::util::{StackGuard, check_stack, get_userdata, push_string, short_type_name, take_userdata};
 use crate::value::Value;

 #[cfg(feature = "async")]
@@ -26,12 +30,12 @@ use {

 // Re-export for convenience
 pub(crate) use cell::UserDataStorage;
-pub use r#ref::{UserDataRef, UserDataRefMut};
+pub use r#ref::{UserDataOwned, UserDataRef, UserDataRefMut};
 pub use registry::UserDataRegistry;
 pub(crate) use registry::{RawUserDataRegistry, UserDataProxy};
 pub(crate) use util::{
-    borrow_userdata_scoped, borrow_userdata_scoped_mut, collect_userdata, init_userdata_metatable,
-    TypeIdHints,
+    TypeIdHints, borrow_userdata_scoped, borrow_userdata_scoped_mut, collect_userdata,
+    init_userdata_metatable,
 };

 /// Kinds of metamethods that can be overridden.
@@ -56,32 +60,53 @@ pub enum MetaMethod {
    /// The unary minus (`-`) operator.
    Unm,
    /// The floor division (//) operator.
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "luau"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "luau")))
+    )]
    IDiv,
    /// The bitwise AND (&) operator.
-    #[cfg(any(feature = "lua54", feature = "lua53"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53")))
+    )]
    BAnd,
    /// The bitwise OR (|) operator.
-    #[cfg(any(feature = "lua54", feature = "lua53"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53")))
+    )]
    BOr,
    /// The bitwise XOR (binary ~) operator.
-    #[cfg(any(feature = "lua54", feature = "lua53"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53")))
+    )]
    BXor,
    /// The bitwise NOT (unary ~) operator.
-    #[cfg(any(feature = "lua54", feature = "lua53"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53")))
+    )]
    BNot,
    /// The bitwise left shift (<<) operator.
-    #[cfg(any(feature = "lua54", feature = "lua53"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53")))
+    )]
    Shl,
    /// The bitwise right shift (>>) operator.
-    #[cfg(any(feature = "lua54", feature = "lua53"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua54", feature = "lua53"))))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(feature = "lua55", feature = "lua54", feature = "lua53")))
+    )]
    Shr,
    /// The string concatenation operator `..`.
    Concat,
@@ -103,13 +128,30 @@ pub enum MetaMethod {
    ///
    /// This is not an operator, but will be called by methods such as `tostring` and `print`.
    ToString,
+    /// The `__todebugstring` metamethod for debug purposes.
+    ///
+    /// This is an mlua-specific metamethod that can be used to provide debug representation for
+    /// userdata.
+    ToDebugString,
    /// The `__pairs` metamethod.
    ///
    /// This is not an operator, but it will be called by the built-in `pairs` function.
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luajit52"))]
+    #[cfg(any(
+        feature = "lua55",
+        feature = "lua54",
+        feature = "lua53",
+        feature = "lua52",
+        feature = "luajit52"
+    ))]
    #[cfg_attr(
        docsrs,
-        doc(cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luajit52")))
+        doc(cfg(any(
+            feature = "lua55",
+            feature = "lua54",
+            feature = "lua53",
+            feature = "lua52",
+            feature = "luajit52"
+        )))
    )]
    Pairs,
    /// The `__ipairs` metamethod.
@@ -135,8 +177,8 @@ pub enum MetaMethod {
    /// [documentation][lua_doc].
    ///
    /// [lua_doc]: https://www.lua.org/manual/5.4/manual.html#3.3.8
-    #[cfg(feature = "lua54")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
+    #[cfg(any(feature = "lua55", feature = "lua54"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "lua55", feature = "lua54"))))]
    Close,
    /// The `__name`/`__type` metafield.
    ///
@@ -152,7 +194,7 @@ impl PartialEq<MetaMethod> for &str {
    }
 }

-impl PartialEq<MetaMethod> for StdString {
+impl PartialEq<MetaMethod> for String {
    fn eq(&self, other: &MetaMethod) -> bool {
        self == other.name()
    }
@@ -176,19 +218,19 @@ impl MetaMethod {
            MetaMethod::Pow => "__pow",
            MetaMethod::Unm => "__unm",

-            #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "luau"))]
            MetaMethod::IDiv => "__idiv",
-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            MetaMethod::BAnd => "__band",
-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            MetaMethod::BOr => "__bor",
-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            MetaMethod::BXor => "__bxor",
-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            MetaMethod::BNot => "__bnot",
-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            MetaMethod::Shl => "__shl",
-            #[cfg(any(feature = "lua54", feature = "lua53"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            MetaMethod::Shr => "__shr",

            MetaMethod::Concat => "__concat",
@@ -200,15 +242,22 @@ impl MetaMethod {
            MetaMethod::NewIndex => "__newindex",
            MetaMethod::Call => "__call",
            MetaMethod::ToString => "__tostring",
+            MetaMethod::ToDebugString => "__todebugstring",

-            #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luajit52"))]
+            #[cfg(any(
+                feature = "lua55",
+                feature = "lua54",
+                feature = "lua53",
+                feature = "lua52",
+                feature = "luajit52"
+            ))]
            MetaMethod::Pairs => "__pairs",
            #[cfg(any(feature = "lua52", feature = "luajit52"))]
            MetaMethod::IPairs => "__ipairs",
            #[cfg(feature = "luau")]
            MetaMethod::Iter => "__iter",

-            #[cfg(feature = "lua54")]
+            #[cfg(any(feature = "lua55", feature = "lua54"))]
            MetaMethod::Close => "__close",

            #[rustfmt::skip]
@@ -240,7 +289,7 @@ impl AsRef<str> for MetaMethod {
    }
 }

-impl From<MetaMethod> for StdString {
+impl From<MetaMethod> for String {
    #[inline]
    fn from(method: MetaMethod) -> Self {
        method.name().to_owned()
@@ -256,7 +305,7 @@ pub trait UserDataMethods<T> {
    ///
    /// If `add_meta_method` is used to set the `__index` metamethod, the `__index` metamethod will
    /// be used as a fall-back if no regular method is found.
-    fn add_method<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_method<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: Fn(&Lua, &T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -267,7 +316,7 @@ pub trait UserDataMethods<T> {
    /// Refer to [`add_method`] for more information about the implementation.
    ///
    /// [`add_method`]: UserDataMethods::add_method
-    fn add_method_mut<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_method_mut<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: FnMut(&Lua, &mut T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -280,8 +329,7 @@ pub trait UserDataMethods<T> {
    ///
    /// The method can be called only once per userdata instance, subsequent calls will result in a
    /// [`Error::UserDataDestructed`] error.
-    #[doc(hidden)]
-    fn add_method_once<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_method_once<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(&Lua, T, A) -> Result<R> + MaybeSend + 'static,
@@ -303,7 +351,7 @@ pub trait UserDataMethods<T> {
    /// [`add_method`]: UserDataMethods::add_method
    #[cfg(feature = "async")]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn add_async_method<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_method<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRef<T>, A) -> MR + MaybeSend + 'static,
@@ -318,7 +366,7 @@ pub trait UserDataMethods<T> {
    /// [`add_method`]: UserDataMethods::add_method
    #[cfg(feature = "async")]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn add_async_method_mut<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_method_mut<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRefMut<T>, A) -> MR + MaybeSend + 'static,
@@ -335,8 +383,7 @@ pub trait UserDataMethods<T> {
    /// [`Error::UserDataDestructed`] error.
    #[cfg(feature = "async")]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    #[doc(hidden)]
-    fn add_async_method_once<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_method_once<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, T, A) -> MR + MaybeSend + 'static,
@@ -359,7 +406,7 @@ pub trait UserDataMethods<T> {
    /// The first argument will be a [`AnyUserData`] of type `T` if the method is called with Lua
    /// method syntax: `my_userdata:my_method(arg1, arg2)`, or it is passed in as the first
    /// argument: `my_userdata.my_method(my_userdata, arg1, arg2)`.
-    fn add_function<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_function<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -370,7 +417,7 @@ pub trait UserDataMethods<T> {
    /// This is a version of [`add_function`] that accepts a `FnMut` argument.
    ///
    /// [`add_function`]: UserDataMethods::add_function
-    fn add_function_mut<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_function_mut<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: FnMut(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -384,7 +431,7 @@ pub trait UserDataMethods<T> {
    /// [`add_function`]: UserDataMethods::add_function
    #[cfg(feature = "async")]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn add_async_function<F, A, FR, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_async_function<F, A, FR, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(Lua, A) -> FR + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -399,7 +446,7 @@ pub trait UserDataMethods<T> {
    /// side has a metatable. To prevent this, use [`add_meta_function`].
    ///
    /// [`add_meta_function`]: UserDataMethods::add_meta_function
-    fn add_meta_method<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_meta_method<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: Fn(&Lua, &T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -413,7 +460,7 @@ pub trait UserDataMethods<T> {
    /// side has a metatable. To prevent this, use [`add_meta_function`].
    ///
    /// [`add_meta_function`]: UserDataMethods::add_meta_function
-    fn add_meta_method_mut<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_meta_method_mut<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: FnMut(&Lua, &mut T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -429,7 +476,7 @@ pub trait UserDataMethods<T> {
        docsrs,
        doc(cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau")))))
    )]
-    fn add_async_meta_method<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_meta_method<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRef<T>, A) -> MR + MaybeSend + 'static,
@@ -445,7 +492,7 @@ pub trait UserDataMethods<T> {
    /// [`add_meta_method_mut`]: UserDataMethods::add_meta_method_mut
    #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn add_async_meta_method_mut<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_meta_method_mut<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRefMut<T>, A) -> MR + MaybeSend + 'static,
@@ -458,7 +505,7 @@ pub trait UserDataMethods<T> {
    /// Metamethods for binary operators can be triggered if either the left or right argument to
    /// the binary operator has a metatable, so the first argument here is not necessarily a
    /// userdata of type `T`.
-    fn add_meta_function<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_meta_function<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -469,7 +516,7 @@ pub trait UserDataMethods<T> {
    /// This is a version of [`add_meta_function`] that accepts a `FnMut` argument.
    ///
    /// [`add_meta_function`]: UserDataMethods::add_meta_function
-    fn add_meta_function_mut<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_meta_function_mut<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: FnMut(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -485,7 +532,7 @@ pub trait UserDataMethods<T> {
        docsrs,
        doc(cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau")))))
    )]
-    fn add_async_meta_function<F, A, FR, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_async_meta_function<F, A, FR, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(Lua, A) -> FR + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -504,7 +551,7 @@ pub trait UserDataFields<T> {
    ///
    /// If `add_meta_method` is used to set the `__index` metamethod, it will
    /// be used as a fall-back if no regular field or method are found.
-    fn add_field<V>(&mut self, name: impl Into<StdString>, value: V)
+    fn add_field<V>(&mut self, name: impl Into<String>, value: V)
    where
        V: IntoLua + 'static;

@@ -515,7 +562,7 @@ pub trait UserDataFields<T> {
    ///
    /// If `add_meta_method` is used to set the `__index` metamethod, the `__index` metamethod will
    /// be used as a fall-back if no regular field or method are found.
-    fn add_field_method_get<M, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_field_method_get<M, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: Fn(&Lua, &T) -> Result<R> + MaybeSend + 'static,
        R: IntoLua;
@@ -528,21 +575,21 @@ pub trait UserDataFields<T> {
    ///
    /// If `add_meta_method` is used to set the `__newindex` metamethod, the `__newindex` metamethod
    /// will be used as a fall-back if no regular field is found.
-    fn add_field_method_set<M, A>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_field_method_set<M, A>(&mut self, name: impl Into<String>, method: M)
    where
        M: FnMut(&Lua, &mut T, A) -> Result<()> + MaybeSend + 'static,
        A: FromLua;

    /// Add a regular field getter as a function which accepts a generic [`AnyUserData`] of type `T`
    /// argument.
-    fn add_field_function_get<F, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_field_function_get<F, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(&Lua, AnyUserData) -> Result<R> + MaybeSend + 'static,
        R: IntoLua;

    /// Add a regular field setter as a function which accepts a generic [`AnyUserData`] of type `T`
    /// first argument.
-    fn add_field_function_set<F, A>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_field_function_set<F, A>(&mut self, name: impl Into<String>, function: F)
    where
        F: FnMut(&Lua, AnyUserData, A) -> Result<()> + MaybeSend + 'static,
        A: FromLua;
@@ -555,7 +602,7 @@ pub trait UserDataFields<T> {
    ///
    /// `mlua` will trigger an error on an attempt to define a protected metamethod,
    /// like `__gc` or `__metatable`.
-    fn add_meta_field<V>(&mut self, name: impl Into<StdString>, value: V)
+    fn add_meta_field<V>(&mut self, name: impl Into<String>, value: V)
    where
        V: IntoLua + 'static;

@@ -567,7 +614,7 @@ pub trait UserDataFields<T> {
    ///
    /// `mlua` will trigger an error on an attempt to define a protected metamethod,
    /// like `__gc` or `__metatable`.
-    fn add_meta_field_with<F, R>(&mut self, name: impl Into<StdString>, f: F)
+    fn add_meta_field_with<F, R>(&mut self, name: impl Into<String>, f: F)
    where
        F: FnOnce(&Lua) -> Result<R> + 'static,
        R: IntoLua;
@@ -667,7 +714,7 @@ pub trait UserData: Sized {
 ///
 /// [`is`]: crate::AnyUserData::is
 /// [`borrow`]: crate::AnyUserData::borrow
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, PartialEq)]
 pub struct AnyUserData(pub(crate) ValueRef);

 impl AnyUserData {
@@ -679,6 +726,14 @@ impl AnyUserData {
        matches!(type_id, Some(type_id) if type_id == TypeId::of::<T>())
    }

+    /// Checks whether the type of this userdata is a [proxy object] for `T`.
+    ///
+    /// [proxy object]: crate::Lua::create_proxy
+    #[inline]
+    pub fn is_proxy<T: 'static>(&self) -> bool {
+        self.is::<UserDataProxy<T>>()
+    }
+
    /// Borrow this userdata immutably if it is of type `T`.
    ///
    /// # Errors
@@ -974,8 +1029,8 @@ impl AnyUserData {

    /// Returns a type name of this userdata (from a metatable field).
    ///
-    /// If no type name is set, returns `None`.
-    pub fn type_name(&self) -> Result<Option<StdString>> {
+    /// If no type name is set, returns `userdata`.
+    pub fn type_name(&self) -> Result<LuaString> {
        let lua = self.0.lua.lock();
        let state = lua.state();
        unsafe {
@@ -992,8 +1047,8 @@ impl AnyUserData {
                ffi::luaL_getmetafield(state, -1, MetaMethod::Type.as_cstr().as_ptr())
            };
            match name_type {
-                ffi::LUA_TSTRING => Ok(Some(String(lua.pop_ref()).to_str()?.to_owned())),
-                _ => Ok(None),
+                ffi::LUA_TSTRING => Ok(LuaString(lua.pop_ref())),
+                _ => lua.create_string(b"userdata"),
            }
        }
    }
@@ -1029,6 +1084,48 @@ impl AnyUserData {
        };
        is_serializable().unwrap_or(false)
    }
+
+    unsafe fn invoke_tostring_dbg(&self) -> Result<Option<String>> {
+        let lua = self.0.lua.lock();
+        let state = lua.state();
+        let _guard = StackGuard::new(state);
+        check_stack(state, 3)?;
+
+        lua.push_ref(&self.0);
+        protect_lua!(state, 1, 1, fn(state) {
+            // Try `__todebugstring` metamethod first, then `__tostring`
+            #[allow(clippy::collapsible_if)]
+            if ffi::luaL_callmeta(state, -1, cstr!("__todebugstring")) == 0 {
+                if ffi::luaL_callmeta(state, -1, cstr!("__tostring")) == 0 {
+                    ffi::lua_pushnil(state);
+                }
+            }
+        })?;
+        Ok(lua.pop_value().as_string().map(|s| s.to_string_lossy()))
+    }
+
+    pub(crate) fn fmt_pretty(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        // Try converting to a (debug) string first, with fallback to `__name/__type`
+        match unsafe { self.invoke_tostring_dbg() } {
+            Ok(Some(s)) => write!(fmt, "{s}"),
+            _ => {
+                let name = self.type_name().ok();
+                let name = (name.as_ref())
+                    .map(|s| Either::Left(s.display()))
+                    .unwrap_or(Either::Right("userdata"));
+                write!(fmt, "{name}: {:?}", self.to_pointer())
+            }
+        }
+    }
+}
+
+impl fmt::Debug for AnyUserData {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        if fmt.alternate() {
+            return self.fmt_pretty(fmt);
+        }
+        fmt.debug_tuple("AnyUserData").field(&self.0).finish()
+    }
 }

 /// Handle to a [`AnyUserData`] metatable.
@@ -1079,13 +1176,13 @@ impl UserDataMetatable {
 /// It skips restricted metamethods, such as `__gc` or `__metatable`.
 ///
 /// This struct is created by the [`UserDataMetatable::pairs`] method.
-pub struct UserDataMetatablePairs<'a, V>(TablePairs<'a, StdString, V>);
+pub struct UserDataMetatablePairs<'a, V>(TablePairs<'a, String, V>);

 impl<V> Iterator for UserDataMetatablePairs<'_, V>
 where
    V: FromLua,
 {
-    type Item = Result<(StdString, V)>;
+    type Item = Result<(String, V)>;

    fn next(&mut self) -> Option<Self::Item> {
        loop {
@@ -1125,7 +1222,7 @@ impl AnyUserData {
    /// Wraps any Rust type, returning an opaque type that implements [`IntoLua`] trait.
    ///
    /// This function uses [`Lua::create_any_userdata`] under the hood.
-    pub fn wrap<T: MaybeSend + 'static>(data: T) -> impl IntoLua {
+    pub fn wrap<T: MaybeSend + MaybeSync + 'static>(data: T) -> impl IntoLua {
        WrappedUserdata(move |lua| lua.create_any_userdata(data))
    }

@@ -1135,7 +1232,7 @@ impl AnyUserData {
    /// This function uses [`Lua::create_ser_any_userdata`] under the hood.
    #[cfg(feature = "serde")]
    #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
-    pub fn wrap_ser<T: Serialize + MaybeSend + 'static>(data: T) -> impl IntoLua {
+    pub fn wrap_ser<T: Serialize + MaybeSend + MaybeSync + 'static>(data: T) -> impl IntoLua {
        WrappedUserdata(move |lua| lua.create_ser_any_userdata(data))
    }
 }
@@ -1,4 +1,4 @@
-use std::cell::{RefCell, UnsafeCell};
+use std::cell::RefCell;

 #[cfg(feature = "serde")]
 use serde::ser::{Serialize, Serializer};
@@ -6,14 +6,14 @@ use serde::ser::{Serialize, Serializer};
 use crate::error::{Error, Result};
 use crate::types::XRc;

-use super::lock::{RawLock, UserDataLock};
+use super::lock::{RawLock, RwLock, UserDataLock};
 use super::r#ref::{UserDataRef, UserDataRefMut};

 #[cfg(all(feature = "serde", not(feature = "send")))]
 type DynSerialize = dyn erased_serde::Serialize;

 #[cfg(all(feature = "serde", feature = "send"))]
-type DynSerialize = dyn erased_serde::Serialize + Send;
+type DynSerialize = dyn erased_serde::Serialize + Send + Sync;

 pub(crate) enum UserDataStorage<T> {
    Owned(UserDataVariant<T>),
@@ -23,9 +23,9 @@ pub(crate) enum UserDataStorage<T> {
 // A enum for storing userdata values.
 // It's stored inside a Lua VM and protected by the outer `ReentrantMutex`.
 pub(crate) enum UserDataVariant<T> {
-    Default(XRc<UserDataCell<T>>),
+    Default(XRc<RwLock<T>>),
    #[cfg(feature = "serde")]
-    Serializable(XRc<UserDataCell<Box<DynSerialize>>>, bool), // bool is `is_sync`
+    Serializable(XRc<RwLock<Box<DynSerialize>>>),
 }

 impl<T> Clone for UserDataVariant<T> {
@@ -34,7 +34,7 @@ impl<T> Clone for UserDataVariant<T> {
        match self {
            Self::Default(inner) => Self::Default(XRc::clone(inner)),
            #[cfg(feature = "serde")]
-            Self::Serializable(inner, is_sync) => Self::Serializable(XRc::clone(inner), *is_sync),
+            Self::Serializable(inner) => Self::Serializable(XRc::clone(inner)),
        }
    }
 }
@@ -42,10 +42,12 @@ impl<T> Clone for UserDataVariant<T> {
 impl<T> UserDataVariant<T> {
    #[inline(always)]
    pub(super) fn try_borrow_scoped<R>(&self, f: impl FnOnce(&T) -> R) -> Result<R> {
-        // We don't need to check for `T: Sync` because when this method is used (internally),
-        // Lua mutex is already locked.
-        // If non-`Sync` userdata is already borrowed by another thread (via `UserDataRef`), it will be
-        // exclusively locked.
+        // Shared (read) lock is always correct for in-place borrows:
+        // - this method is called internally while the Lua mutex is held, ensuring exclusive Lua-level
+        //   access per call frame
+        // - with `send` feature, all owned userdata satisfies `T: Sync`, so simultaneous shared references
+        //   from multiple threads are sound
+        // - without `send` feature, single-threaded execution makes shared lock safe for any `T`
        let _guard = (self.raw_lock().try_lock_shared_guarded()).map_err(|_| Error::UserDataBorrowError)?;
        Ok(f(unsafe { &*self.as_ptr() }))
    }
@@ -78,10 +80,12 @@ impl<T> UserDataVariant<T> {
            return Err(Error::UserDataBorrowMutError);
        }
        Ok(match self {
-            Self::Default(inner) => XRc::into_inner(inner).unwrap().value.into_inner(),
+            Self::Default(inner) => XRc::into_inner(inner).unwrap().into_inner(),
            #[cfg(feature = "serde")]
-            Self::Serializable(inner, _) => unsafe {
-                let raw = Box::into_raw(XRc::into_inner(inner).unwrap().value.into_inner());
+            Self::Serializable(inner) => unsafe {
+                // The serde variant erases `T` to `Box<DynSerialize>`, so we
+                // must cast the raw pointer back to recover the concrete type.
+                let raw = Box::into_raw(XRc::into_inner(inner).unwrap().into_inner());
                *Box::from_raw(raw as *mut T)
            },
        })
@@ -92,25 +96,25 @@ impl<T> UserDataVariant<T> {
        match self {
            Self::Default(inner) => XRc::strong_count(inner),
            #[cfg(feature = "serde")]
-            Self::Serializable(inner, _) => XRc::strong_count(inner),
+            Self::Serializable(inner) => XRc::strong_count(inner),
        }
    }

    #[inline(always)]
    pub(super) fn raw_lock(&self) -> &RawLock {
        match self {
-            Self::Default(inner) => &inner.raw_lock,
+            Self::Default(inner) => unsafe { inner.raw() },
            #[cfg(feature = "serde")]
-            Self::Serializable(inner, _) => &inner.raw_lock,
+            Self::Serializable(inner) => unsafe { inner.raw() },
        }
    }

    #[inline(always)]
    pub(super) fn as_ptr(&self) -> *mut T {
        match self {
-            Self::Default(inner) => inner.value.get(),
+            Self::Default(inner) => inner.data_ptr(),
            #[cfg(feature = "serde")]
-            Self::Serializable(inner, _) => unsafe { &mut **(inner.value.get() as *mut Box<T>) },
+            Self::Serializable(inner) => unsafe { (&mut **inner.data_ptr()) as *mut DynSerialize as *mut T },
        }
    }
 }
@@ -119,51 +123,16 @@ impl<T> UserDataVariant<T> {
 impl Serialize for UserDataStorage<()> {
    fn serialize<S: Serializer>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error> {
        match self {
-            Self::Owned(variant @ UserDataVariant::Serializable(inner, is_sync)) => unsafe {
-                #[cfg(feature = "send")]
-                if *is_sync {
-                    let _guard = (variant.raw_lock().try_lock_shared_guarded())
-                        .map_err(|_| serde::ser::Error::custom(Error::UserDataBorrowError))?;
-                    (*inner.value.get()).serialize(serializer)
-                } else {
-                    let _guard = (variant.raw_lock().try_lock_exclusive_guarded())
-                        .map_err(|_| serde::ser::Error::custom(Error::UserDataBorrowError))?;
-                    (*inner.value.get()).serialize(serializer)
-                }
-                #[cfg(not(feature = "send"))]
-                {
-                    let _ = is_sync;
-                    let _guard = (variant.raw_lock().try_lock_shared_guarded())
-                        .map_err(|_| serde::ser::Error::custom(Error::UserDataBorrowError))?;
-                    (*inner.value.get()).serialize(serializer)
-                }
+            Self::Owned(variant @ UserDataVariant::Serializable(inner)) => unsafe {
+                let _guard = (variant.raw_lock().try_lock_shared_guarded())
+                    .map_err(|_| serde::ser::Error::custom(Error::UserDataBorrowError))?;
+                (*inner.data_ptr()).serialize(serializer)
            },
            _ => Err(serde::ser::Error::custom("cannot serialize <userdata>")),
        }
    }
 }

-/// A type that provides interior mutability for a userdata value (thread-safe).
-pub(crate) struct UserDataCell<T> {
-    raw_lock: RawLock,
-    value: UnsafeCell<T>,
-}
-
-#[cfg(feature = "send")]
-unsafe impl<T: Send> Send for UserDataCell<T> {}
-#[cfg(feature = "send")]
-unsafe impl<T: Send> Sync for UserDataCell<T> {}
-
-impl<T> UserDataCell<T> {
-    #[inline(always)]
-    fn new(value: T) -> Self {
-        UserDataCell {
-            raw_lock: RawLock::INIT,
-            value: UnsafeCell::new(value),
-        }
-    }
-}
-
 pub(crate) enum ScopedUserDataVariant<T> {
    Ref(*const T),
    RefMut(RefCell<*mut T>),
@@ -173,10 +142,10 @@ pub(crate) enum ScopedUserDataVariant<T> {
 impl<T> Drop for ScopedUserDataVariant<T> {
    #[inline]
    fn drop(&mut self) {
-        if let Self::Boxed(value) = self {
-            if let Ok(value) = value.try_borrow_mut() {
-                unsafe { drop(Box::from_raw(*value)) };
-            }
+        if let Self::Boxed(value) = self
+            && let Ok(value) = value.try_borrow_mut()
+        {
+            unsafe { drop(Box::from_raw(*value)) }
        }
    }
 }
@@ -184,7 +153,7 @@ impl<T> Drop for ScopedUserDataVariant<T> {
 impl<T: 'static> UserDataStorage<T> {
    #[inline(always)]
    pub(crate) fn new(data: T) -> Self {
-        Self::Owned(UserDataVariant::Default(XRc::new(UserDataCell::new(data))))
+        Self::Owned(UserDataVariant::Default(XRc::new(RwLock::new(data))))
    }

    #[inline(always)]
@@ -201,11 +170,10 @@ impl<T: 'static> UserDataStorage<T> {
    #[inline(always)]
    pub(crate) fn new_ser(data: T) -> Self
    where
-        T: Serialize + crate::types::MaybeSend,
+        T: Serialize + crate::types::MaybeSend + crate::types::MaybeSync,
    {
        let data = Box::new(data) as Box<DynSerialize>;
-        let is_sync = super::util::is_sync::<T>();
-        let variant = UserDataVariant::Serializable(XRc::new(UserDataCell::new(data)), is_sync);
+        let variant = UserDataVariant::Serializable(XRc::new(RwLock::new(data)));
        Self::Owned(variant)
    }

@@ -1,6 +1,4 @@
 pub(crate) trait UserDataLock {
-    const INIT: Self;
-
    fn is_locked(&self) -> bool;
    fn try_lock_shared(&self) -> bool;
    fn try_lock_exclusive(&self) -> bool;
@@ -48,12 +46,12 @@ impl<L: UserDataLock + ?Sized> Drop for LockGuard<'_, L> {
    }
 }

-pub(crate) use lock_impl::RawLock;
+pub(crate) use lock_impl::{RawLock, RwLock};

 #[cfg(not(feature = "send"))]
 #[cfg(not(tarpaulin_include))]
 mod lock_impl {
-    use std::cell::Cell;
+    use std::cell::{Cell, UnsafeCell};

    // Positive values represent the number of read references.
    // Negative values represent the number of write references (only one allowed).
@@ -62,9 +60,6 @@ mod lock_impl {
    const UNUSED: isize = 0;

    impl super::UserDataLock for RawLock {
-        #[allow(clippy::declare_interior_mutable_const)]
-        const INIT: Self = Cell::new(UNUSED);
-
        #[inline(always)]
        fn is_locked(&self) -> bool {
            self.get() != UNUSED
@@ -72,7 +67,7 @@ mod lock_impl {

        #[inline(always)]
        fn try_lock_shared(&self) -> bool {
-            let flag = self.get().wrapping_add(1);
+            let flag = self.get().checked_add(1).expect("userdata lock count overflow");
            if flag <= UNUSED {
                return false;
            }
@@ -104,41 +99,71 @@ mod lock_impl {
            self.set(flag + 1);
        }
    }
+
+    /// A cheap single-threaded read-write lock pairing a `parking_lot::RwLock` type.
+    pub(crate) struct RwLock<T> {
+        lock: RawLock,
+        data: UnsafeCell<T>,
+    }
+
+    impl<T> RwLock<T> {
+        /// Creates a new `RwLock` containing the given value.
+        #[inline(always)]
+        pub(crate) fn new(value: T) -> Self {
+            RwLock {
+                lock: RawLock::new(UNUSED),
+                data: UnsafeCell::new(value),
+            }
+        }
+
+        /// Returns a reference to the underlying raw lock.
+        #[inline(always)]
+        pub(crate) unsafe fn raw(&self) -> &RawLock {
+            &self.lock
+        }
+
+        /// Returns a raw pointer to the underlying data.
+        #[inline(always)]
+        pub(crate) fn data_ptr(&self) -> *mut T {
+            self.data.get()
+        }
+
+        /// Consumes this `RwLock`, returning the underlying data.
+        #[inline(always)]
+        pub(crate) fn into_inner(self) -> T {
+            self.data.into_inner()
+        }
+    }
 }

 #[cfg(feature = "send")]
 mod lock_impl {
-    use parking_lot::lock_api::RawRwLock;
-
-    pub(crate) type RawLock = parking_lot::RawRwLock;
+    pub(crate) use parking_lot::{RawRwLock as RawLock, RwLock};

    impl super::UserDataLock for RawLock {
-        #[allow(clippy::declare_interior_mutable_const)]
-        const INIT: Self = <Self as parking_lot::lock_api::RawRwLock>::INIT;
-
        #[inline(always)]
        fn is_locked(&self) -> bool {
-            RawRwLock::is_locked(self)
+            parking_lot::lock_api::RawRwLock::is_locked(self)
        }

        #[inline(always)]
        fn try_lock_shared(&self) -> bool {
-            RawRwLock::try_lock_shared(self)
+            parking_lot::lock_api::RawRwLock::try_lock_shared(self)
        }

        #[inline(always)]
        fn try_lock_exclusive(&self) -> bool {
-            RawRwLock::try_lock_exclusive(self)
+            parking_lot::lock_api::RawRwLock::try_lock_exclusive(self)
        }

        #[inline(always)]
        unsafe fn unlock_shared(&self) {
-            RawRwLock::unlock_shared(self)
+            parking_lot::lock_api::RawRwLock::unlock_shared(self)
        }

        #[inline(always)]
        unsafe fn unlock_exclusive(&self) {
-            RawRwLock::unlock_exclusive(self)
+            parking_lot::lock_api::RawRwLock::unlock_exclusive(self)
        }
    }
 }
@@ -1,12 +1,10 @@
-use std::string::String as StdString;
-
+use crate::Function;
 use crate::error::{Error, Result};
 use crate::state::WeakLua;
 use crate::table::Table;
 use crate::traits::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, ObjectLike};
 use crate::userdata::AnyUserData;
 use crate::value::Value;
-use crate::Function;

 #[cfg(feature = "async")]
 use crate::function::AsyncCallFuture;
@@ -88,7 +86,7 @@ impl ObjectLike for AnyUserData {
    }

    #[inline]
-    fn to_string(&self) -> Result<StdString> {
+    fn to_string(&self) -> Result<String> {
        Value::UserData(self.clone()).to_string()
    }

@@ -1,4 +1,4 @@
-use std::any::{type_name, TypeId};
+use std::any::{TypeId, type_name};
 use std::ops::{Deref, DerefMut};
 use std::os::raw::c_int;
 use std::{fmt, mem};
@@ -7,12 +7,11 @@ use crate::error::{Error, Result};
 use crate::state::{Lua, RawLua};
 use crate::traits::FromLua;
 use crate::userdata::AnyUserData;
-use crate::util::get_userdata;
+use crate::util::{check_stack, get_userdata, take_userdata};
 use crate::value::Value;

 use super::cell::{UserDataStorage, UserDataVariant};
 use super::lock::{LockGuard, RawLock, UserDataLock};
-use super::util::is_sync;

 #[cfg(feature = "userdata-wrappers")]
 use {
@@ -63,11 +62,10 @@ impl<T> TryFrom<UserDataVariant<T>> for UserDataRef<T> {

    #[inline]
    fn try_from(variant: UserDataVariant<T>) -> Result<Self> {
-        let guard = if cfg!(not(feature = "send")) || is_sync::<T>() {
-            variant.raw_lock().try_lock_shared_guarded()
-        } else {
-            variant.raw_lock().try_lock_exclusive_guarded()
-        };
+        // Shared (read) lock is always correct:
+        // - with `send` feature, `T: Sync` is guaranteed by the `MaybeSync` bound on userdata creation
+        // - without `send` feature, single-threaded access makes shared lock safe for any `T`
+        let guard = variant.raw_lock().try_lock_shared_guarded();
        let guard = guard.map_err(|_| Error::UserDataBorrowError)?;
        let guard = unsafe { mem::transmute::<LockGuard<_>, LockGuard<'static, _>>(guard) };
        Ok(UserDataRef::from_parts(UserDataRefInner::Default(variant), guard))
@@ -442,15 +440,75 @@ impl<T> DerefMut for UserDataRefMutInner<T> {
    }
 }

+/// A wrapper type that takes ownership of a userdata value.
+///
+/// It implements [`FromLua`] and can be used to receive a typed userdata from Lua by taking
+/// ownership of it.
+/// The original Lua userdata is marked as destructed and cannot be used further.
+pub struct UserDataOwned<T>(pub T);
+
+impl<T> Deref for UserDataOwned<T> {
+    type Target = T;
+
+    #[inline]
+    fn deref(&self) -> &T {
+        &self.0
+    }
+}
+
+impl<T> DerefMut for UserDataOwned<T> {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut T {
+        &mut self.0
+    }
+}
+
+impl<T: fmt::Debug> fmt::Debug for UserDataOwned<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        (**self).fmt(f)
+    }
+}
+
+impl<T: fmt::Display> fmt::Display for UserDataOwned<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        (**self).fmt(f)
+    }
+}
+
+impl<T: 'static> FromLua for UserDataOwned<T> {
+    fn from_lua(value: Value, _: &Lua) -> Result<Self> {
+        try_value_to_userdata::<T>(value)?.take().map(UserDataOwned)
+    }
+
+    unsafe fn from_stack(idx: c_int, lua: &RawLua) -> Result<Self> {
+        let state = lua.state();
+        let type_id = lua.get_userdata_type_id::<T>(state, idx)?;
+        match type_id {
+            Some(type_id) if type_id == TypeId::of::<T>() => {
+                let ud = get_userdata::<UserDataStorage<T>>(state, idx);
+                if (*ud).has_exclusive_access() {
+                    check_stack(state, 1)?;
+                    take_userdata::<UserDataStorage<T>>(state, idx)
+                        .into_inner()
+                        .map(UserDataOwned)
+                } else {
+                    Err(Error::UserDataBorrowMutError)
+                }
+            }
+            _ => Err(Error::UserDataTypeMismatch),
+        }
+    }
+}
+
 #[inline]
 fn try_value_to_userdata<T>(value: Value) -> Result<AnyUserData> {
    match value {
        Value::UserData(ud) => Ok(ud),
-        _ => Err(Error::FromLuaConversionError {
-            from: value.type_name(),
-            to: "userdata".to_string(),
-            message: Some(format!("expected userdata of type {}", type_name::<T>())),
-        }),
+        _ => Err(Error::from_lua_conversion(
+            value.type_name(),
+            "userdata",
+            format!("expected userdata of type {}", type_name::<T>()),
+        )),
    }
 }

@@ -466,6 +524,10 @@ mod assertions {
    static_assertions::assert_impl_all!(UserDataRefMut<()>: Sync, Send);
    #[cfg(feature = "send")]
    static_assertions::assert_not_impl_all!(UserDataRefMut<std::rc::Rc<()>>: Send, Sync);
+    #[cfg(feature = "send")]
+    static_assertions::assert_impl_all!(UserDataOwned<()>: Send, Sync);
+    #[cfg(feature = "send")]
+    static_assertions::assert_not_impl_all!(UserDataOwned<std::rc::Rc<()>>: Send, Sync);

    #[cfg(not(feature = "send"))]
    static_assertions::assert_not_impl_all!(UserDataRef<()>: Send, Sync);
@@ -4,15 +4,14 @@ use std::any::TypeId;
 use std::cell::RefCell;
 use std::marker::PhantomData;
 use std::os::raw::c_void;
-use std::string::String as StdString;

 use crate::error::{Error, Result};
 use crate::state::{Lua, LuaGuard};
 use crate::traits::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti};
 use crate::types::{Callback, MaybeSend};
 use crate::userdata::{
-    borrow_userdata_scoped, borrow_userdata_scoped_mut, AnyUserData, MetaMethod, TypeIdHints, UserData,
-    UserDataFields, UserDataMethods, UserDataStorage,
+    AnyUserData, MetaMethod, TypeIdHints, UserData, UserDataFields, UserDataMethods, UserDataStorage,
+    borrow_userdata_scoped, borrow_userdata_scoped_mut,
 };
 use crate::util::short_type_name;
 use crate::value::Value;
@@ -55,7 +54,7 @@ pub(crate) struct RawUserDataRegistry {

    pub(crate) destructor: ffi::lua_CFunction,
    pub(crate) type_id: Option<TypeId>,
-    pub(crate) type_name: StdString,
+    pub(crate) type_name: String,

    #[cfg(feature = "luau")]
    pub(crate) enable_namecall: bool,
@@ -368,7 +367,7 @@ impl<T> UserDataRegistry<T> {
                        method: name.to_string(),
                        type_name: value.type_name(),
                        message: Some("expected nil, table or function".to_string()),
-                    })
+                    });
                }
            }
        }
@@ -382,12 +381,12 @@ impl<T> UserDataRegistry<T> {
 }

 // Returns function name for the type `T`, without the module path
-fn get_function_name<T>(name: &str) -> StdString {
+fn get_function_name<T>(name: &str) -> String {
    format!("{}.{name}", short_type_name::<T>())
 }

 impl<T> UserDataFields<T> for UserDataRegistry<T> {
-    fn add_field<V>(&mut self, name: impl Into<StdString>, value: V)
+    fn add_field<V>(&mut self, name: impl Into<String>, value: V)
    where
        V: IntoLua + 'static,
    {
@@ -395,7 +394,7 @@ impl<T> UserDataFields<T> for UserDataRegistry<T> {
        self.raw.fields.push((name, value.into_lua(self.lua.lua())));
    }

-    fn add_field_method_get<M, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_field_method_get<M, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: Fn(&Lua, &T) -> Result<R> + MaybeSend + 'static,
        R: IntoLua,
@@ -405,7 +404,7 @@ impl<T> UserDataFields<T> for UserDataRegistry<T> {
        self.raw.field_getters.push((name, callback));
    }

-    fn add_field_method_set<M, A>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_field_method_set<M, A>(&mut self, name: impl Into<String>, method: M)
    where
        M: FnMut(&Lua, &mut T, A) -> Result<()> + MaybeSend + 'static,
        A: FromLua,
@@ -415,7 +414,7 @@ impl<T> UserDataFields<T> for UserDataRegistry<T> {
        self.raw.field_setters.push((name, callback));
    }

-    fn add_field_function_get<F, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_field_function_get<F, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(&Lua, AnyUserData) -> Result<R> + MaybeSend + 'static,
        R: IntoLua,
@@ -425,7 +424,7 @@ impl<T> UserDataFields<T> for UserDataRegistry<T> {
        self.raw.field_getters.push((name, callback));
    }

-    fn add_field_function_set<F, A>(&mut self, name: impl Into<StdString>, mut function: F)
+    fn add_field_function_set<F, A>(&mut self, name: impl Into<String>, mut function: F)
    where
        F: FnMut(&Lua, AnyUserData, A) -> Result<()> + MaybeSend + 'static,
        A: FromLua,
@@ -435,7 +434,7 @@ impl<T> UserDataFields<T> for UserDataRegistry<T> {
        self.raw.field_setters.push((name, callback));
    }

-    fn add_meta_field<V>(&mut self, name: impl Into<StdString>, value: V)
+    fn add_meta_field<V>(&mut self, name: impl Into<String>, value: V)
    where
        V: IntoLua + 'static,
    {
@@ -445,7 +444,7 @@ impl<T> UserDataFields<T> for UserDataRegistry<T> {
        self.raw.meta_fields.push((name, field));
    }

-    fn add_meta_field_with<F, R>(&mut self, name: impl Into<StdString>, f: F)
+    fn add_meta_field_with<F, R>(&mut self, name: impl Into<String>, f: F)
    where
        F: FnOnce(&Lua) -> Result<R> + 'static,
        R: IntoLua,
@@ -458,7 +457,7 @@ impl<T> UserDataFields<T> for UserDataRegistry<T> {
 }

 impl<T> UserDataMethods<T> for UserDataRegistry<T> {
-    fn add_method<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_method<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: Fn(&Lua, &T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -469,7 +468,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
        self.raw.methods.push((name, callback));
    }

-    fn add_method_mut<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_method_mut<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: FnMut(&Lua, &mut T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -481,7 +480,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
    }

    #[cfg(feature = "async")]
-    fn add_async_method<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_method<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRef<T>, A) -> MR + MaybeSend + 'static,
@@ -495,7 +494,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
    }

    #[cfg(feature = "async")]
-    fn add_async_method_mut<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_method_mut<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRefMut<T>, A) -> MR + MaybeSend + 'static,
@@ -508,7 +507,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
        self.raw.async_methods.push((name, callback));
    }

-    fn add_function<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_function<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -519,7 +518,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
        self.raw.methods.push((name, callback));
    }

-    fn add_function_mut<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_function_mut<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: FnMut(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -531,7 +530,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
    }

    #[cfg(feature = "async")]
-    fn add_async_function<F, A, FR, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_async_function<F, A, FR, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(Lua, A) -> FR + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -543,7 +542,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
        self.raw.async_methods.push((name, callback));
    }

-    fn add_meta_method<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_meta_method<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: Fn(&Lua, &T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -554,7 +553,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
        self.raw.meta_methods.push((name, callback));
    }

-    fn add_meta_method_mut<M, A, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_meta_method_mut<M, A, R>(&mut self, name: impl Into<String>, method: M)
    where
        M: FnMut(&Lua, &mut T, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -566,7 +565,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
    }

    #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
-    fn add_async_meta_method<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_meta_method<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRef<T>, A) -> MR + MaybeSend + 'static,
@@ -580,7 +579,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
    }

    #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
-    fn add_async_meta_method_mut<M, A, MR, R>(&mut self, name: impl Into<StdString>, method: M)
+    fn add_async_meta_method_mut<M, A, MR, R>(&mut self, name: impl Into<String>, method: M)
    where
        T: 'static,
        M: Fn(Lua, UserDataRefMut<T>, A) -> MR + MaybeSend + 'static,
@@ -593,7 +592,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
        self.raw.async_meta_methods.push((name, callback));
    }

-    fn add_meta_function<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_meta_function<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -604,7 +603,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
        self.raw.meta_methods.push((name, callback));
    }

-    fn add_meta_function_mut<F, A, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_meta_function_mut<F, A, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: FnMut(&Lua, A) -> Result<R> + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -616,7 +615,7 @@ impl<T> UserDataMethods<T> for UserDataRegistry<T> {
    }

    #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
-    fn add_async_meta_function<F, A, FR, R>(&mut self, name: impl Into<StdString>, function: F)
+    fn add_async_meta_function<F, A, FR, R>(&mut self, name: impl Into<String>, function: F)
    where
        F: Fn(Lua, A) -> FR + MaybeSend + 'static,
        A: FromLuaMulti,
@@ -655,6 +654,12 @@ macro_rules! lua_userdata_impl {
 // A special proxy object for UserData
 pub(crate) struct UserDataProxy<T>(pub(crate) PhantomData<T>);

+// `UserDataProxy` holds no real `T` value, only a type marker, so it is always safe to send/share.
+#[cfg(feature = "send")]
+unsafe impl<T> Send for UserDataProxy<T> {}
+#[cfg(feature = "send")]
+unsafe impl<T> Sync for UserDataProxy<T> {}
+
 lua_userdata_impl!(UserDataProxy<T>);

 #[cfg(all(feature = "userdata-wrappers", not(feature = "send")))]
@@ -1,6 +1,4 @@
 use std::any::TypeId;
-use std::cell::Cell;
-use std::marker::PhantomData;
 use std::os::raw::c_int;
 use std::ptr;

@@ -11,35 +9,6 @@ use crate::error::{Error, Result};
 use crate::types::CallbackPtr;
 use crate::util::{get_userdata, rawget_field, rawset_field, take_userdata};

-// This is a trick to check if a type is `Sync` or not.
-// It uses leaked specialization feature from stdlib.
-struct IsSync<'a, T> {
-    is_sync: &'a Cell<bool>,
-    _marker: PhantomData<T>,
-}
-
-impl<T> Clone for IsSync<'_, T> {
-    fn clone(&self) -> Self {
-        self.is_sync.set(false);
-        IsSync {
-            is_sync: self.is_sync,
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<T: Sync> Copy for IsSync<'_, T> {}
-
-pub(crate) fn is_sync<T>() -> bool {
-    let is_sync = Cell::new(true);
-    let _ = [IsSync::<T> {
-        is_sync: &is_sync,
-        _marker: PhantomData,
-    }]
-    .clone();
-    is_sync.get()
-}
-
 // Userdata type hints,  used to match types of wrapped userdata
 #[derive(Clone, Copy)]
 pub(crate) struct TypeIdHints {
@@ -2,15 +2,15 @@ use std::any::Any;
 use std::fmt::Write as _;
 use std::mem::MaybeUninit;
 use std::os::raw::{c_int, c_void};
-use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe};
+use std::panic::{AssertUnwindSafe, catch_unwind, resume_unwind};
 use std::ptr;
 use std::sync::Arc;

 use crate::error::{Error, Result};
 use crate::memory::MemoryState;
 use crate::util::{
-    check_stack, get_internal_userdata, init_internal_metatable, push_internal_userdata, push_string,
-    push_table, rawset_field, to_string, TypeKey, DESTRUCTED_USERDATA_METATABLE,
+    DESTRUCTED_USERDATA_METATABLE, TypeKey, check_stack, get_internal_userdata, init_internal_metatable,
+    push_internal_userdata, push_string, push_table, rawset_field, to_string,
 };

 static WRAPPED_FAILURE_TYPE_KEY: u8 = 0;
@@ -197,7 +197,7 @@ where
    F: FnOnce(*mut ffi::lua_State) -> R,
    R: Copy,
 {
-    struct Params<F, R: Copy> {
+    struct Params<F, R> {
        function: Option<F>,
        result: MaybeUninit<R>,
        nresults: c_int,
@@ -208,7 +208,7 @@ where
        F: FnOnce(*mut ffi::lua_State) -> R,
        R: Copy,
    {
-        let params = ffi::lua_touserdata(state, -1) as *mut Params<F, R>;
+        let params = ffi::lua_tolightuserdata(state, -1) as *mut Params<F, R>;
        ffi::lua_pop(state, 1);

        let f = (*params).function.take().unwrap();
@@ -239,7 +239,7 @@ where

    ffi::lua_pushlightuserdata(state, &mut params as *mut Params<F, R> as *mut c_void);
    let ret = ffi::lua_pcall(state, nargs + 1, nresults, stack_start + 1);
-    ffi::lua_remove(state, stack_start + 1);
+    ffi::lua_remove(state, stack_start + 1); // remove error handler

    if ret == ffi::LUA_OK {
        // `LUA_OK` is only returned when the `do_call` function has completed successfully, so
@@ -373,19 +373,19 @@ pub(crate) unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<(
        "__mod",
        "__pow",
        "__unm",
-        #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "luau"))]
        "__idiv",
-        #[cfg(any(feature = "lua54", feature = "lua53"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
        "__band",
-        #[cfg(any(feature = "lua54", feature = "lua53"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
        "__bor",
-        #[cfg(any(feature = "lua54", feature = "lua53"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
        "__bxor",
-        #[cfg(any(feature = "lua54", feature = "lua53"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
        "__bnot",
-        #[cfg(any(feature = "lua54", feature = "lua53"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
        "__shl",
-        #[cfg(any(feature = "lua54", feature = "lua53"))]
+        #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
        "__shr",
        "__concat",
        "__len",
@@ -396,7 +396,13 @@ pub(crate) unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<(
        "__newindex",
        "__call",
        "__tostring",
-        #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", feature = "luajit52"))]
+        #[cfg(any(
+            feature = "lua55",
+            feature = "lua54",
+            feature = "lua53",
+            feature = "lua52",
+            feature = "luajit52"
+        ))]
        "__pairs",
        #[cfg(any(feature = "lua53", feature = "lua52", feature = "luajit52"))]
        "__ipairs",
@@ -404,7 +410,7 @@ pub(crate) unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<(
        "__iter",
        #[cfg(feature = "luau")]
        "__namecall",
-        #[cfg(feature = "lua54")]
+        #[cfg(any(feature = "lua55", feature = "lua54"))]
        "__close",
    ] {
        ffi::lua_pushvalue(state, -1);
@@ -6,16 +6,16 @@ use std::{ptr, slice, str};
 use crate::error::{Error, Result};

 pub(crate) use error::{
-    error_traceback, error_traceback_thread, init_error_registry, pop_error, protect_lua_call,
-    protect_lua_closure, WrappedFailure,
+    WrappedFailure, error_traceback, error_traceback_thread, init_error_registry, pop_error,
+    protect_lua_call, protect_lua_closure,
 };
 pub(crate) use path::parse_path as parse_lookup_path;
 pub(crate) use short_names::short_type_name;
 pub(crate) use types::TypeKey;
 pub(crate) use userdata::{
-    get_destructed_userdata_metatable, get_internal_metatable, get_internal_userdata, get_userdata,
-    init_internal_metatable, push_internal_userdata, push_userdata, take_userdata,
-    DESTRUCTED_USERDATA_METATABLE,
+    DESTRUCTED_USERDATA_METATABLE, get_destructed_userdata_metatable, get_internal_metatable,
+    get_internal_userdata, get_userdata, init_internal_metatable, push_internal_userdata, push_userdata,
+    take_userdata,
 };

 #[cfg(not(feature = "luau"))]
@@ -99,6 +99,38 @@ pub(crate) unsafe fn push_string(state: *mut ffi::lua_State, s: &[u8], protect:
    }
 }

+// Uses 3 (or 1 if unprotected) stack spaces, does not call checkstack.
+#[cfg(feature = "lua55")]
+pub(crate) unsafe fn push_external_string(
+    state: *mut ffi::lua_State,
+    mut bytes: Vec<u8>,
+    protect: bool,
+) -> Result<()> {
+    bytes.push(0);
+    let s_len = bytes.len() - 1; // exclude null terminator
+    let s_ptr = bytes.as_ptr() as *const c_char;
+    let bytes_ud = Box::into_raw(Box::new(bytes));
+
+    unsafe extern "C" fn dealloc(ud: *mut c_void, _: *mut c_void, _: usize, _: usize) -> *mut c_void {
+        drop(Box::from_raw(ud as *mut Vec<u8>));
+        ptr::null_mut()
+    }
+
+    if protect {
+        let res = protect_lua!(state, 0, 1, move |state| {
+            ffi::lua_pushexternalstring(state, s_ptr, s_len, Some(dealloc), bytes_ud as *mut _);
+        });
+        if res.is_err() {
+            // Deallocate on error
+            drop(Box::from_raw(bytes_ud));
+            return res;
+        }
+    } else {
+        ffi::lua_pushexternalstring(state, s_ptr, s_len, Some(dealloc), bytes_ud as *mut _);
+    }
+    Ok(())
+}
+
 // Uses 3 stack spaces (when protect), does not call checkstack.
 #[cfg(feature = "luau")]
 #[inline(always)]
@@ -220,7 +252,7 @@ pub(crate) unsafe extern "C-unwind" fn safe_xpcall(state: *mut ffi::lua_State) -
 // Returns Lua main thread for Lua >= 5.2 or checks that the passed thread is main for Lua 5.1.
 // Does not call lua_checkstack, uses 1 stack space.
 pub(crate) unsafe fn get_main_state(state: *mut ffi::lua_State) -> Option<*mut ffi::lua_State> {
-    #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
+    #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53", feature = "lua52"))]
    {
        ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_RIDX_MAINTHREAD);
        let main_state = ffi::lua_tothread(state, -1);
@@ -232,11 +264,7 @@ pub(crate) unsafe fn get_main_state(state: *mut ffi::lua_State) -> Option<*mut f
        // Check the current state first
        let is_main_state = ffi::lua_pushthread(state) == 1;
        ffi::lua_pop(state, 1);
-        if is_main_state {
-            Some(state)
-        } else {
-            None
-        }
+        if is_main_state { Some(state) } else { None }
    }
    #[cfg(feature = "luau")]
    Some(ffi::lua_mainthread(state))
@@ -196,7 +196,7 @@ fn unquote_string<'a>(path: &'a str, chars: &mut Peekable<CharIndices<'a>>) -> R

 #[cfg(test)]
 mod tests {
-    use super::{parse_path, PathKey};
+    use super::{PathKey, parse_path};

    #[test]
    fn test_parse_path() {
@@ -3,7 +3,7 @@ use std::{mem, ptr};

 use crate::error::Result;
 use crate::userdata::collect_userdata;
-use crate::util::{check_stack, get_metatable_ptr, push_table, rawset_field, TypeKey};
+use crate::util::{TypeKey, check_stack, get_metatable_ptr, push_table, rawset_field};

 // Pushes the userdata and attaches a metatable with __gc method.
 // Internally uses 3 stack spaces, does not call checkstack.
@@ -1,19 +1,18 @@
 use std::cmp::Ordering;
 use std::collections::HashSet;
 use std::os::raw::c_void;
-use std::string::String as StdString;
 use std::{fmt, ptr, str};

 use num_traits::FromPrimitive;

 use crate::error::{Error, Result};
 use crate::function::Function;
-use crate::string::{BorrowedStr, String};
+use crate::string::{BorrowedStr, LuaString};
 use crate::table::Table;
 use crate::thread::Thread;
 use crate::types::{Integer, LightUserData, Number, ValueRef};
 use crate::userdata::AnyUserData;
-use crate::util::{check_stack, StackGuard};
+use crate::util::{StackGuard, check_stack};

 #[cfg(feature = "serde")]
 use {
@@ -50,7 +49,7 @@ pub enum Value {
    /// An interned string, managed by Lua.
    ///
    /// Unlike Rust strings, Lua strings may not be valid UTF-8.
-    String(String),
+    String(LuaString),
    /// Reference to a Lua table.
    Table(Table),
    /// Reference to a Lua function (or closure).
@@ -129,18 +128,13 @@ impl Value {
    #[inline]
    pub fn to_pointer(&self) -> *const c_void {
        match self {
-            Value::String(String(vref)) => {
-                // In Lua < 5.4 (excluding Luau), string pointers are NULL
-                // Use alternative approach
-                let lua = vref.lua.lock();
-                unsafe { ffi::lua_tostring(lua.ref_thread(), vref.index) as *const c_void }
-            }
            Value::LightUserData(ud) => ud.0,
            Value::Table(Table(vref))
            | Value::Function(Function(vref))
            | Value::Thread(Thread(vref, ..))
            | Value::UserData(AnyUserData(vref))
            | Value::Other(vref) => vref.to_pointer(),
+            Value::String(s) => s.to_pointer(),
            #[cfg(feature = "luau")]
            Value::Buffer(crate::Buffer(vref)) => vref.to_pointer(),
            _ => ptr::null(),
@@ -151,8 +145,8 @@ impl Value {
    ///
    /// This might invoke the `__tostring` metamethod for non-primitive types (eg. tables,
    /// functions).
-    pub fn to_string(&self) -> Result<StdString> {
-        unsafe fn invoke_to_string(vref: &ValueRef) -> Result<StdString> {
+    pub fn to_string(&self) -> Result<String> {
+        unsafe fn invoke_tostring(vref: &ValueRef) -> Result<String> {
            let lua = vref.lua.lock();
            let state = lua.state();
            let _guard = StackGuard::new(state);
@@ -162,7 +156,7 @@ impl Value {
            protect_lua!(state, 1, 1, fn(state) {
                ffi::luaL_tolstring(state, -1, ptr::null_mut());
            })?;
-            Ok(String(lua.pop_ref()).to_str()?.to_string())
+            Ok(LuaString(lua.pop_ref()).to_str()?.to_string())
        }

        match self {
@@ -179,9 +173,9 @@ impl Value {
            | Value::Function(Function(vref))
            | Value::Thread(Thread(vref, ..))
            | Value::UserData(AnyUserData(vref))
-            | Value::Other(vref) => unsafe { invoke_to_string(vref) },
+            | Value::Other(vref) => unsafe { invoke_tostring(vref) },
            #[cfg(feature = "luau")]
-            Value::Buffer(crate::Buffer(vref)) => unsafe { invoke_to_string(vref) },
+            Value::Buffer(crate::Buffer(vref)) => unsafe { invoke_tostring(vref) },
            Value::Error(err) => Ok(err.to_string()),
        }
    }
@@ -336,17 +330,17 @@ impl Value {
        self.as_number()
    }

-    /// Returns `true` if the value is a Lua [`String`].
+    /// Returns `true` if the value is a [`LuaString`].
    #[inline]
    pub fn is_string(&self) -> bool {
        self.as_string().is_some()
    }

-    /// Cast the value to Lua [`String`].
+    /// Cast the value to a [`LuaString`].
    ///
-    /// If the value is a Lua [`String`], returns it or `None` otherwise.
+    /// If the value is a [`LuaString`], returns it or `None` otherwise.
    #[inline]
-    pub fn as_string(&self) -> Option<&String> {
+    pub fn as_string(&self) -> Option<&LuaString> {
        match self {
            Value::String(s) => Some(s),
            _ => None,
@@ -355,26 +349,26 @@ impl Value {

    /// Cast the value to [`BorrowedStr`].
    ///
-    /// If the value is a Lua [`String`], try to convert it to [`BorrowedStr`] or return `None`
+    /// If the value is a [`LuaString`], try to convert it to [`BorrowedStr`] or return `None`
    /// otherwise.
    #[deprecated(
        since = "0.11.0",
        note = "This method does not follow Rust naming convention. Use `as_string().and_then(|s| s.to_str().ok())` instead."
    )]
    #[inline]
-    pub fn as_str(&self) -> Option<BorrowedStr<'_>> {
+    pub fn as_str(&self) -> Option<BorrowedStr> {
        self.as_string().and_then(|s| s.to_str().ok())
    }

-    /// Cast the value to [`StdString`].
+    /// Cast the value to [`String`].
    ///
-    /// If the value is a Lua [`String`], converts it to [`StdString`] or returns `None` otherwise.
+    /// If the value is a [`LuaString`], converts it to [`String`] or returns `None` otherwise.
    #[deprecated(
        since = "0.11.0",
        note = "This method does not follow Rust naming convention. Use `as_string().map(|s| s.to_string_lossy())` instead."
    )]
    #[inline]
-    pub fn as_string_lossy(&self) -> Option<StdString> {
+    pub fn as_string_lossy(&self) -> Option<String> {
        self.as_string().map(|s| s.to_string_lossy())
    }

@@ -562,15 +556,7 @@ impl Value {
            t @ Value::Table(_) => write!(fmt, "table: {:?}", t.to_pointer()),
            f @ Value::Function(_) => write!(fmt, "function: {:?}", f.to_pointer()),
            t @ Value::Thread(_) => write!(fmt, "thread: {:?}", t.to_pointer()),
-            u @ Value::UserData(ud) => {
-                // Try `__name/__type` first then `__tostring`
-                let name = ud.type_name().ok().flatten();
-                let s = name
-                    .map(|name| format!("{name}: {:?}", u.to_pointer()))
-                    .or_else(|| u.to_string().ok())
-                    .unwrap_or_else(|| format!("userdata: {:?}", u.to_pointer()));
-                write!(fmt, "{s}")
-            }
+            Value::UserData(ud) => ud.fmt_pretty(fmt),
            #[cfg(feature = "luau")]
            buf @ Value::Buffer(_) => write!(fmt, "buffer: {:?}", buf.to_pointer()),
            Value::Error(e) if recursive => write!(fmt, "{e:?}"),
@@ -1,11 +1,11 @@
-[lua54]
-features = "lua54,vendored,async,send,serde,macros,anyhow,userdata-wrappers"
+[lua55]
+features = "lua55,vendored,async,send,serde,macros,anyhow,userdata-wrappers"

-[lua54_non_send]
-features = "lua54,vendored,async,serde,macros,anyhow,userdata-wrappers"
+[lua55_non_send]
+features = "lua55,vendored,async,serde,macros,anyhow,userdata-wrappers"

-[lua54_with_memory_limit]
-features = "lua54,vendored,async,send,serde,macros,anyhow,userdata-wrappers"
+[lua55_with_memory_limit]
+features = "lua55,vendored,async,send,serde,macros,anyhow,userdata-wrappers"
 rustflags = "--cfg force_memory_limit"

 [lua51]
@@ -1,6 +1,5 @@
 #![cfg(feature = "async")]

-use std::string::String as StdString;
 use std::sync::Arc;
 use std::time::Duration;

@@ -8,7 +7,7 @@ use futures_util::stream::TryStreamExt;
 use tokio::sync::Mutex;

 use mlua::{
-    Error, Function, Lua, LuaOptions, MultiValue, ObjectLike, Result, StdLib, Table, ThreadStatus, UserData,
+    Error, Function, Lua, LuaOptions, MultiValue, ObjectLike, Result, StdLib, Table, UserData,
    UserDataMethods, UserDataRef, Value,
 };

@@ -40,9 +39,9 @@ async fn test_async_function() -> Result<()> {
 async fn test_async_function_wrap() -> Result<()> {
    let lua = Lua::new();

-    let f = Function::wrap_async(|s: StdString| async move {
+    let f = Function::wrap_async(|s: String| async move {
        tokio::task::yield_now().await;
-        Ok(s)
+        Ok::<_, Error>(s)
    });
    lua.globals().set("f", f)?;
    let res: String = lua.load(r#"f("hello")"#).eval_async().await?;
@@ -68,7 +67,7 @@ async fn test_async_function_wrap() -> Result<()> {
 async fn test_async_function_wrap_raw() -> Result<()> {
    let lua = Lua::new();

-    let f = Function::wrap_raw_async(|s: StdString| async move {
+    let f = Function::wrap_raw_async(|s: String| async move {
        tokio::task::yield_now().await;
        s
    });
@@ -249,7 +248,7 @@ async fn test_async_return_async_closure() -> Result<()> {
    Ok(())
 }

-#[cfg(feature = "lua54")]
+#[cfg(any(feature = "lua55", feature = "lua54"))]
 #[tokio::test]
 async fn test_async_lua54_to_be_closed() -> Result<()> {
    let lua = Lua::new();
@@ -670,7 +669,7 @@ async fn test_async_hook() -> Result<()> {
    static HOOK_CALLED: AtomicBool = AtomicBool::new(false);
    lua.set_global_hook(mlua::HookTriggers::new().every_line(), move |_, _| {
        if !HOOK_CALLED.swap(true, Ordering::Relaxed) {
-            #[cfg(any(feature = "lu53", feature = "lua54"))]
+            #[cfg(any(feature = "lua55", feature = "lua54", feature = "lua53"))]
            return Ok(mlua::VmState::Yield);
        }
        Ok(mlua::VmState::Continue)
@@ -715,7 +714,7 @@ fn test_async_yield_with() -> Result<()> {
    assert_eq!(thread.resume::<(i32, i32)>((10, 11))?, (21, 110));
    assert_eq!(thread.resume::<(i32, i32)>((11, 12))?, (23, 132));
    assert_eq!(thread.resume::<(i32, i32)>((12, 13))?, (0, 0));
-    assert_eq!(thread.status(), ThreadStatus::Finished);
+    assert!(thread.is_finished());

    Ok(())
 }
@@ -1,3 +1,4 @@
+#[cfg(not(target_os = "wasi"))]
 use std::{fs, io};

 use mlua::{Chunk, ChunkMode, Lua, Result};
@@ -85,7 +86,7 @@ fn test_chunk_macro() -> Result<()> {
    data.raw_set("num", 1)?;

    let ud = mlua::AnyUserData::wrap("hello");
-    let f = mlua::Function::wrap(|| Ok(()));
+    let f = mlua::Function::wrap(|| Ok::<_, mlua::Error>(()));

    lua.globals().set("g", 123)?;

@@ -109,6 +110,21 @@ fn test_chunk_macro() -> Result<()> {

    assert_eq!(lua.globals().get::<i32>("s")?, 321);

+    // Check line numbers in error reporting
+    match lua
+        .load(mlua::chunk! {
+            local x = 1
+            -- comment
+            error("boom")
+        })
+        .exec()
+    {
+        Err(mlua::Error::RuntimeError(ref msg)) => {
+            assert!(msg.contains(":3:"), "expected line 3, got: {msg}");
+        }
+        other => panic!("expected RuntimeError, got {other:?}"),
+    }
+
    Ok(())
 }

@@ -21,4 +21,27 @@ fn test_compilation() {
    t.compile_fail("tests/compile/non_send.rs");
    #[cfg(not(feature = "send"))]
    t.pass("tests/compile/non_send.rs");
+
+    #[cfg(feature = "macros")]
+    {
+        t.compile_fail("tests/compile/chunk_dollar_non_ident.rs");
+        t.compile_fail("tests/compile/userdata_getter_and_meta.rs");
+        t.compile_fail("tests/compile/userdata_getter_and_setter.rs");
+        t.compile_fail("tests/compile/userdata_getter_mut_self.rs");
+        t.compile_fail("tests/compile/userdata_getter_extra_arg.rs");
+        t.compile_fail("tests/compile/userdata_setter_ref_self.rs");
+        t.compile_fail("tests/compile/userdata_mut_slice_arg.rs");
+        t.compile_fail("tests/compile/userdata_setter_no_value.rs");
+        t.compile_fail("tests/compile/userdata_static_with_self.rs");
+        t.compile_fail("tests/compile/userdata_meta_owned_self.rs");
+        t.compile_fail("tests/compile/userdata_const_getter.rs");
+        t.compile_fail("tests/compile/userdata_field_with_args.rs");
+    }
+
+    #[cfg(all(feature = "macros", feature = "async"))]
+    {
+        t.compile_fail("tests/compile/userdata_getter_async.rs");
+        t.compile_fail("tests/compile/userdata_setter_async.rs");
+        t.compile_fail("tests/compile/userdata_field_async.rs");
+    }
 }
@@ -1,15 +1,23 @@
 error[E0596]: cannot borrow `s` as mutable, as it is a captured variable in a `Fn` closure
  --> tests/compile/async_any_userdata_method.rs:9:49
   |
-9  |         reg.add_async_method("t", |_, this, ()| async {
-   |                                                 ^^^^^ cannot borrow as mutable
-10 |             s = &*this;
-   |             - mutable borrow occurs due to use of `s` in closure
+ 8 |           let mut s = &s;
+   |               ----- `s` declared here, outside the closure
+ 9 |           reg.add_async_method("t", |_, this, ()| async {
+   |               -                     ------------- ^^^^^ cannot borrow as mutable
+   |               |                     |
+   |  _____________|                     in this closure
+   | |
+10 | |             s = &*this;
+   | |             - mutable borrow occurs due to use of `s` in closure
+11 | |             Ok(())
+12 | |         });
+   | |__________- expects `Fn` instead of `FnMut`

 error[E0373]: async block may outlive the current function, but it borrows `this`, which is owned by the current function
  --> tests/compile/async_any_userdata_method.rs:9:49
   |
-9  |         reg.add_async_method("t", |_, this, ()| async {
+ 9 |         reg.add_async_method("t", |_, this, ()| async {
   |                                                 ^^^^^ may outlive borrowed value `this`
 10 |             s = &*this;
   |                   ---- `this` is borrowed here
@@ -17,7 +25,7 @@ error[E0373]: async block may outlive the current function, but it borrows `this
 note: async block is returned here
  --> tests/compile/async_any_userdata_method.rs:9:49
   |
-9  |           reg.add_async_method("t", |_, this, ()| async {
+ 9 |           reg.add_async_method("t", |_, this, ()| async {
   |  _________________________________________________^
 10 | |             s = &*this;
 11 | |             Ok(())
@@ -25,13 +33,13 @@ note: async block is returned here
   | |_________^
 help: to force the async block to take ownership of `this` (and any other referenced variables), use the `move` keyword
   |
-9  |         reg.add_async_method("t", |_, this, ()| async move {
+ 9 |         reg.add_async_method("t", |_, this, ()| async move {
   |                                                       ++++

 error: lifetime may not live long enough
  --> tests/compile/async_any_userdata_method.rs:9:49
   |
-9  |           reg.add_async_method("t", |_, this, ()| async {
+ 9 |           reg.add_async_method("t", |_, this, ()| async {
   |  ___________________________________-------------_^
   | |                                   |           |
   | |                                   |           return type of closure `{async block@$DIR/tests/compile/async_any_userdata_method.rs:9:49: 9:54}` contains a lifetime `'2`
@@ -46,22 +54,28 @@ error: lifetime may not live long enough
 error[E0597]: `s` does not live long enough
  --> tests/compile/async_any_userdata_method.rs:8:21
   |
-7  |           let s = String::new();
+ 7 |           let s = String::new();
   |               - binding `s` declared here
-8  |           let mut s = &s;
+ 8 |           let mut s = &s;
   |                       ^^ borrowed value does not live long enough
-9  | /         reg.add_async_method("t", |_, this, ()| async {
+ 9 | /         reg.add_async_method("t", |_, this, ()| async {
 10 | |             s = &*this;
 11 | |             Ok(())
 12 | |         });
   | |__________- argument requires that `s` is borrowed for `'static`
 13 |       })
   |       - `s` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> src/userdata.rs
+   |
+   |         M: Fn(Lua, UserDataRef<T>, A) -> MR + MaybeSend + 'static,
+   |                                                           ^^^^^^^

 error[E0373]: closure may outlive the current function, but it borrows `s`, which is owned by the current function
  --> tests/compile/async_any_userdata_method.rs:9:35
   |
-9  |         reg.add_async_method("t", |_, this, ()| async {
+ 9 |         reg.add_async_method("t", |_, this, ()| async {
   |                                   ^^^^^^^^^^^^^ may outlive borrowed value `s`
 10 |             s = &*this;
   |             - `s` is borrowed here
@@ -69,12 +83,12 @@ error[E0373]: closure may outlive the current function, but it borrows `s`, whic
 note: function requires argument type to outlive `'static`
  --> tests/compile/async_any_userdata_method.rs:9:9
   |
-9  | /         reg.add_async_method("t", |_, this, ()| async {
+ 9 | /         reg.add_async_method("t", |_, this, ()| async {
 10 | |             s = &*this;
 11 | |             Ok(())
 12 | |         });
   | |__________^
 help: to force the closure to take ownership of `s` (and any other referenced variables), use the `move` keyword
   |
-9  |         reg.add_async_method("t", move |_, this, ()| async {
+ 9 |         reg.add_async_method("t", move |_, this, ()| async {
   |                                   ++++
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Alex Orlenko	0711c614c7	v0.12.0-rc.2	2026-06-06 14:28:31 +01:00
Alex Orlenko	743325f7d6	clippy	2026-06-06 14:28:31 +01:00
Alex Orlenko	0b365e92a9	Support `to_alias_override`/`to_alias_fallback` in `Require` trait (Luau)	2026-06-06 14:11:59 +01:00
Alex Orlenko	15fb63b2a2	Support thread create/resume/yield callbacks for all Lua/Luau versions Introduce new `Lua::set_thread_event_callback` function to register callback for thread events. Thread collection callback is removed as unlikely very usefil and has too many limitations.	2026-06-01 00:25:12 +01:00
Alex Orlenko	0849d05c83	mlua_derive: Update docs	2026-05-31 13:45:48 +01:00
Alex Orlenko	38c05b850e	mlua_derive: Improve error reporting for #[lua] attributes	2026-05-31 13:32:33 +01:00
Alex Orlenko	8d1841f8cf	Fix tests (Luau 0.723 integer type)	2026-05-31 13:22:50 +01:00
Alex Orlenko	e9271d2e32	mlua_derive: Use correct Span in metamethod name validation error	2026-05-31 13:17:40 +01:00
Alex Orlenko	e263220fb3	Add documentation for `#derive(UserData)`	2026-05-31 13:05:03 +01:00
Alex Orlenko	e6d16815d7	mlua_derive: Improve context-aware validation for `#[lua]` attr	2026-05-31 12:56:15 +01:00
Alex Orlenko	ae88e8acf8	mlua_derive: Detect (and reject) all generic type parameters in UserData derive	2026-05-31 12:31:35 +01:00
Alex Orlenko	fcab60bac4	mlua_derive: Fix `#[lua(meta, field)]` case	2026-05-31 12:28:06 +01:00
Alex Orlenko	208a70f407	Move inlined `#[lua_module]` proc macro doc to docs/lua_module.md	2026-05-31 11:17:51 +01:00
Alex Orlenko	ca360f9019	Move inlined `chunk!` macro doc to docs/chunk.md	2026-05-31 11:16:40 +01:00
Alex Orlenko	a7c5a24a7b	mlua_derive: Deny `#[lua = "..."]` syntax	2026-05-30 22:23:03 +01:00
Alex Orlenko	b7c98ad9bb	mlua_derive: Switch from `#[userdata]` to `[derive(UserData)]`	2026-05-30 13:11:26 +01:00
Alex Orlenko	1f3dafa564	mlua_derive: Reject static field functions with args	2026-05-30 12:46:31 +01:00
Alex Orlenko	1d4a756436	mlua_derive: Support async userdata methods in macro	2026-05-29 00:56:33 +01:00
Alex Orlenko	6e7d6c78ed	mlua_derive: Group functionality in modules Create new `chunk`, `userdata`, `module` modules.	2026-05-26 23:23:09 +01:00
Alex Orlenko	023e4c61d8	mlua_derive: Fix compilation / remove "if let" guards	2026-05-26 23:23:09 +01:00
Alex Orlenko	92bd06d3c1	mlua_derive: Refactor `Capture` implementation for `chunk!`	2026-05-26 23:23:09 +01:00
Alex Orlenko	d8544bf038	mlua_derive: Optimize `Captures::add`	2026-05-26 23:23:09 +01:00
Alex Orlenko	7114c03489	mlua_derive: Remove unneeded `Span::line` hack for chunk! since we use Rust 1.95+	2026-05-26 23:23:09 +01:00
Alex Orlenko	f4cacc524e	mlua_derive: Bump MSRV to 1.88	2026-05-26 23:23:09 +01:00
Alex Orlenko	cc7f7ce7b7	mlua_derive: show better error message when $ is not followed by ident	2026-05-26 23:23:09 +01:00
Alex Orlenko	72de602ec3	Fix modules compilation after switching to 2024 edition in mlua_derive	2026-05-26 23:23:09 +01:00
Alex Orlenko	1573dd1242	Add #[mlua::userdata] and #[mlua::userdata_impl] macros	2026-05-26 23:23:09 +01:00
Alex Orlenko	39d3201848	Prevent `XRc` overflow when dropping `RawLua` with foreign Lua state Calling `lua_close` triggers GC collection of the `ExtraData` that cascades to `RawLua::drop` where extra is already decremented to 0, causing a subtraction overflow.	2026-05-26 23:18:24 +01:00
莯凛	4aa6214b45	feat: implement `Not` for `StdLib` (#699 )	2026-04-30 22:56:50 +01:00
Alex Orlenko	72824a468a	Remove custom `PartialEq` for `LuaString` and use derived one Lua can compare strings using `lua_rawequal` and it's more efficient than always compare bytes. Under the hood Lua compare pointers for interned strings and content for long ones. Close #694	2026-04-22 22:30:45 +01:00
Alex Orlenko	c54b90623c	Fix `String::to_pointer` return NULL in Lua <5.4 Lua 5.4+ can return string pointer when calling `lua_topointer`. In earlier Lua versions this API always returns NULL. Let's unify this behavior.	2026-04-22 22:23:25 +01:00
Alex Orlenko	5f0e06fb66	Update CHANGELOG	2026-04-22 00:06:11 +01:00
Alex Orlenko	181c9d07b7	v0.12.0-rc.1	2026-04-20 00:24:58 +01:00
Alex Orlenko	4e827179d1	Update compile tests messages	2026-04-20 00:19:56 +01:00
Alex Orlenko	cc26dcd4ff	Bump rustyline	2026-04-20 00:16:34 +01:00
Alex Orlenko	201e30bc07	Add `UserDataOwned<T>` wrapper to take ownership of userdata `T` It implements `FromLua` and takes ownership of a Lua userdata value. The semantics is similar to `AnyUserData::take`, preventing any further use from Lua. Closes #686	2026-04-20 00:05:57 +01:00
Alex Orlenko	4e028d8409	Change `AnyUserData::type_name` to return `LuaString` instead. This avoids unnecessary allocation and returns type name as it stored in metatable.	2026-04-19 23:26:24 +01:00
Alex Orlenko	3d1ae981d3	Update docs	2026-04-19 22:12:17 +01:00
Alex Orlenko	8c93948f2f	Fix tests	2026-04-18 16:13:23 +01:00
Alex Orlenko	f2b5cc44de	`traits` module no longer need to be public The LuaNativeFn traits were moved to the `function` module and all other traits as re-exported.	2026-04-18 16:09:17 +01:00
Alex Orlenko	27f91dfd1b	Accept any error in `Function::wrap/wrap_mut/wrap_async` Previously wrapped functions were required to return `mlua::Result`. Now it's possible to wrap functions returning any errors as long as they implement `std::error::Error`. Existing code remains compatible with `mlua::Result` as this type is not converted to an external error.	2026-04-18 16:01:35 +01:00
Alex Orlenko	75ff11f795	Move LuaNativeFn/Mut into `function` module	2026-04-18 14:56:24 +01:00
Alex Orlenko	df6097ab38	Mark Luau `CompileConstant` as non_exhaustive	2026-04-18 14:51:54 +01:00
Alex Orlenko	65bb6279ee	Update serde types visibility	2026-04-18 14:47:26 +01:00
Alex Orlenko	31b88e85bb	cargo fmt	2026-04-18 13:26:42 +01:00
Alex Orlenko	3be4745190	Add initial Luau integer64 type support RFC: https://rfcs.luau.org/type-long-integer.html Unfortunately this type is not backward compatible with regular numbers and require a special "integer" library. It's not integrated with `Value` enum to keep it simple.	2026-04-18 13:14:05 +01:00
Alex Orlenko	c52deec988	Use c_int for userdata metatable id	2026-04-18 13:14:05 +01:00
三咲雅 misaki masa	3ab3c997b3	feat: support external strings for `Cow<str>` and `Cow<CStr>` (#692 )	2026-04-09 10:45:15 +01:00
Alex Orlenko	5872ed70f5	Make `traits` module public	2026-04-04 15:04:00 +01:00
Alex Orlenko	e7e92b4f6f	Make `chunk` module public	2026-04-03 13:58:05 +01:00
Alex Orlenko	d27693b61a	Make `error` module public	2026-03-29 10:26:45 +01:00
Alex Orlenko	c9848d6faf	Update doc/example for (hidden) `Lua::exec_raw_lua`	2026-03-28 23:57:35 +00:00
Alex Orlenko	9126bb8ce0	Add `RawLua::pop` method	2026-03-28 22:37:25 +00:00
Alex Orlenko	7f1d716a44	Remove deprecated `Lua::load_from_function`	2026-03-28 17:40:22 +00:00
Alex Orlenko	be56e2205c	Update GC `step_size` doc	2026-03-28 17:38:49 +00:00
Alex Orlenko	c5aadc68cd	Open `UserDataMethods::add_method_once` and `UserDataMethods::add_async_method_once`	2026-03-28 17:17:57 +00:00
Alex Orlenko	a5ae2a1fc3	Update useratom doc	2026-03-28 17:07:03 +00:00
Alex Orlenko	59872da63d	mlua-sys: Bump lua-src and luajit-src dependencies	2026-03-28 16:31:19 +00:00
Alex Orlenko	a24d2151af	Minor fixes in docs	2026-03-27 22:54:56 +00:00
Alex Orlenko	56c227fd7e	Make `state` module public	2026-03-08 00:06:18 +00:00
Alex Orlenko	d5d66abe42	Refactor GC control API - Replace `gc_inc/gc_gen` with `gc_set_mode` - Add `GcIncParams` and `GcGenParams` for GC tuning - Remove `gc_step_kbytes` (it's very rare needed and Lua 5.5 has changed the input param from kbytes to bytes)	2026-03-07 23:52:10 +00:00
Alex Orlenko	a2d8b21964	Make `luau` module public	2026-03-01 16:40:19 +00:00
Alex Orlenko	a9604c4946	Rename Luau's TextRequirer to FsRequirer	2026-03-01 16:27:41 +00:00
Alex Orlenko	81ae8e1393	Make `Chunk::wrap` public	2026-03-01 16:17:11 +00:00
Alex Orlenko	a959b98d30	Add chunk module doc and update prelude re-exports	2026-03-01 16:11:38 +00:00
Alex Orlenko	efd0856033	Derive `PartialEq` for `Thread`	2026-02-28 14:52:59 +00:00
Alex Orlenko	c91066006f	Make `thread` module public	2026-02-28 14:44:50 +00:00
Alex Orlenko	a45fe9bb93	Bump luau-src to 0.19 (Luau 0.710)	2026-02-28 12:03:37 +00:00
Alex Orlenko	f1a97e4193	Open `Thread::state()` that returns `*mut lua_State` pointer.	2026-02-28 11:48:59 +00:00
Alex Orlenko	47e6a37323	Add shortcuts to check thread status (`Thread::is_resumable()`, `Thread::is_finished()` etc)	2026-02-28 11:46:05 +00:00
Alex Orlenko	bf0c96908f	Remove lifetime from `BorrowedStr` and `BorrowedBytes` The underlying `ValueRef` is cheap to clone as only increases reference count, instead of allocating a new Lua stack slot.	2026-02-23 10:24:31 +00:00
Alex Orlenko	8817720362	Re-export (hidden) `TablePairs` and `TableSequence`	2026-02-23 09:51:24 +00:00
Alex Orlenko	35294359ad	Inline doc for some types	2026-02-22 19:58:28 +00:00
Alex Orlenko	eb76db59da	Make `userdata` module public	2026-02-22 19:52:57 +00:00
Alex Orlenko	33bf3ffde7	Fix doc warnings	2026-02-22 14:37:23 +00:00
Alex Orlenko	0f3fdb0539	Make `string` module public	2026-02-22 14:33:38 +00:00
Alex Orlenko	79d438aaad	Build CI docs on main branch	2026-02-22 13:28:48 +00:00
Alex Orlenko	30cf4bef58	Use RwLock directly instead of UserDataCell	2026-02-22 00:13:19 +00:00
Alex Orlenko	5776c72208	Use `parking_lot::RwLock` in `UserDataCell` container in "send" mode. In non-send mode, mimic the `RwLock` API (using `Cell<isize>` counter). We're continue manually operating the underlying `RawRwLock` for flexibility.	2026-02-21 23:18:39 +00:00
Alex Orlenko	943c3aed58	Some minor fixes in userdata cell	2026-02-21 21:19:42 +00:00
Alex Orlenko	8fcb6a8416	Update dependencies	2026-02-21 15:38:00 +00:00
Alex Orlenko	452dc8be88	clippy	2026-02-21 15:31:48 +00:00
Alex Orlenko	63a255bbc9	Replace `is_sync` specialization trick with `MaybeSync` trait bound. The `is_sync::<T>()` runtime check relied on implicit specialization via `Copy`/`Clone` array behavior, which has changed in Rust 1.86+. `UserDataRef` always taking an exclusive lock even for `Sync` userdata, preventing concurrent shared borrows. With the `send` feature flag enabled, userdata types must now be `Send + Sync`. This is a breaking change, `T: Send + !Sync` userdata types can be wrapped in a `Mutex` or used inside a `Scope` where this restriction is lifted.	2026-02-21 15:05:55 +00:00
Alex Orlenko	151adc0e87	Implement pretty debug format for `AnyUserData` similar to `Value::UserData`.	2026-02-20 20:31:29 +00:00
Alex Orlenko	7f3ec63ab5	Support `__todebugstring` for pretty userdata debug output Close #681	2026-02-20 18:59:53 +00:00
Alex Orlenko	f19c6aac3b	Fix tests	2026-02-12 16:20:51 +00:00
Alex Orlenko	29af448ad9	Update README to indicate dev status	2026-02-12 15:28:32 +00:00
Alex Orlenko	497d84828a	Add CI to build dev docs	2026-02-03 22:40:29 +00:00
Alex Orlenko	0e489901a5	Update `debug` module Move debug types from root to new new module.	2026-02-03 22:39:33 +00:00
Alex Orlenko	88063e756f	Make `table` module public	2026-01-30 13:18:46 +00:00
Alex Orlenko	c8436e2b80	Make `function` module public Reduce number of function-specific types exported to the mlua root and keep them inside the module.	2026-01-30 13:18:05 +00:00
Alex Orlenko	613748ec16	Use `Error::from_lua_conversion` helper	2026-01-29 23:09:52 +00:00
Alex Orlenko	2fbd266da6	Remove `Error::ToLuaConversionError` This variant used only once and not practically useful.	2026-01-29 23:04:30 +00:00
Alex Orlenko	c79b5e9cdb	cargo fmt	2026-01-29 23:03:56 +00:00
Alex Orlenko	2ace892613	Rename `string::String` to `LuaString`	2026-01-29 18:45:41 +00:00
Alex Orlenko	c1ffd4e790	Replace `get_or_insert_with` with `get_or_insert_default`	2026-01-29 10:46:58 +00:00
Alex Orlenko	d9c139b55f	Rust 2024	2026-01-29 10:33:28 +00:00
Alex Orlenko	0c4206c97d	Bump min Rust version to 1.88	2026-01-29 10:13:04 +00:00
Alex Orlenko	a985dc7a37	Start 0.12.0-dev.1	2026-01-29 10:07:05 +00:00
Alex Orlenko	e7fa8d75bb	v0.11.6	2026-01-27 16:06:24 +00:00
Alex Orlenko	c10718ed2f	Update CHANGELOG	2026-01-27 16:04:33 +00:00
Alex Orlenko	ec2ce3620f	Some final Lua 5.5 updates	2026-01-27 16:00:49 +00:00
Alex Orlenko	71757003c7	mlua-sys: v0.10.0	2026-01-27 15:56:53 +00:00
Alex Orlenko	6bb7f09927	Don't use `luaL_typename` to get a static type name in Luau. In Luau this function returns heap-allocated string rather than static string, so accessing this value when Lua state is destroyed is UB. Fixes #674	2026-01-27 14:10:43 +00:00
Alex Orlenko	e67ae7f0de	Make `RawLua::{push,push_value,pop_value}` public	2026-01-27 12:17:58 +00:00
Alex Orlenko	8c1535c27b	cargo fmt	2026-01-27 12:14:50 +00:00
WASDetchan	fd245daa6f	Expose RawLua via Lua::exec_raw_lua (#670 )	2026-01-23 16:19:10 +00:00
Alex Orlenko	7fb7e8685f	Update spelling check	2026-01-23 15:37:18 +00:00
Alex Orlenko	93617eef4e	Update trybuild (compile) messages	2026-01-23 15:16:35 +00:00
Alex Orlenko	171cdf1758	Some fixes and more tests for `Function::info`	2026-01-23 12:44:22 +00:00
psentee	3f8f016daa	Add num_params, is_vararg, nups to FunctionInfo (#665 )	2026-01-23 11:59:59 +00:00
Alex Orlenko	86d0c9bddb	More multi borrow "send" test fixes due to regression in Rust 1.93+	2026-01-22 23:08:17 +00:00
Alex Orlenko	86d63ef27b	Fix missing BUFSIZ for wasm32 in libc	2026-01-22 15:46:31 +00:00
Alex Orlenko	e33bcf7938	Add Lua 5.5 external string null byte test	2026-01-22 15:32:14 +00:00
Alex Orlenko	c80a97b526	Ignore userdata_multithread_access_sync test	2026-01-22 15:25:18 +00:00
Alex Orlenko	3c40cfe199	mlua-sys: Use 2024 edition	2026-01-22 14:09:14 +00:00
Alex Orlenko	e9efb73125	Update Luau FFI bindings (added some missing functions)	2026-01-22 14:05:57 +00:00
Alex Orlenko	386c6d8ed8	Update Lua 5.5 FFI bindings (add buffer manipulation, etc)	2026-01-22 12:54:55 +00:00
Alex Orlenko	8f086bf837	Update Lua 5.4 FFI bindings (add buffer manipulation, etc)	2026-01-22 12:50:56 +00:00
Alex Orlenko	ad167612dc	Update Lua 5.3 FFI bindings (add buffer manipulation, etc)	2026-01-20 15:36:36 +00:00
Alex Orlenko	3366f47d40	Minor Lua 5.2 fixes	2026-01-20 15:28:33 +00:00
Alex Orlenko	0b5ef91f44	Update Lua 5.2 FFI bindings (add buffer manipulation, etc)	2026-01-20 14:29:35 +00:00
Alex Orlenko	a162b0ceca	Update Lua 5.1 FFI bindings (add buffer manipulation, etc)	2026-01-20 14:29:15 +00:00
Alex Orlenko	8e6d652a21	Bump luau-src to 0.18.0 (Luau 0.705)	2026-01-20 13:05:00 +00:00
Alex Orlenko	1be9e6ce2d	Add Lua 5.5 external strings support	2026-01-18 00:03:43 +00:00
Alex Orlenko	b1f99aa852	Update tests	2026-01-17 13:26:13 +00:00
Alex Orlenko	4c5465229e	Update CI	2026-01-14 21:44:25 +00:00
Alex Orlenko	9b24bb2319	Add Lua 5.5 to CI	2026-01-14 16:01:04 +00:00
Alex Orlenko	e1701b6b56	cargo fmt	2026-01-14 15:57:52 +00:00
Alex Orlenko	77d7d5d6bd	Add initial Lua 5.5 support	2026-01-13 23:43:31 +00:00
psentee	ee9232eda1	AnyUserData::is_proxy (#666 )	2026-01-13 15:08:38 +00:00
Alex Orlenko	da526595bb	mlua-sys: Add Lua 5.5 support	2026-01-13 00:05:01 +00:00
Alex Orlenko	39a7d3b862	Update `SYS_MIN_ALIGN`	2025-12-31 19:26:38 +02:00