v0.9.0-rc.1

Can be useful for low-level intergration with mlua values.
Also closes #215.

.github/workflows/main.yml

@@ -9,7 +9,7 @@ jobs:
       matrix:
         os: [ubuntu-22.04, macos-latest, windows-latest]
         rust: [stable]
-        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit]
+        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
         include:
           - os: ubuntu-22.04
             target: x86_64-unknown-linux-gnu
@@ -104,7 +104,7 @@ jobs:
       matrix:
         os: [ubuntu-22.04, macos-latest, windows-latest]
         rust: [stable, nightly]
-        lua: [lua54, lua53, lua52, lua51, luajit, luajit52, luau, luau-jit]
+        lua: [lua54, lua53, lua52, lua51, luajit, luajit52, luau, luau-jit, luau-vector4]
         include:
           - os: ubuntu-22.04
             target: x86_64-unknown-linux-gnu
@@ -140,7 +140,7 @@ jobs:
       matrix:
         os: [ubuntu-22.04]
         rust: [nightly]
-        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit]
+        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
         include:
           - os: ubuntu-22.04
             target: x86_64-unknown-linux-gnu
@@ -222,7 +222,7 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit]
+        lua: [lua54, lua53, lua52, lua51, luajit, luau, luau-jit, luau-vector4]
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@stable

CHANGELOG.md

@@ -1,3 +1,17 @@
+## v0.9.0-rc.1
+
+- `UserDataMethods::add_async_method()` takes `&T` instead of cloning `T`
+- Implemented `PartialEq<[T]>` for tables
+- Added Luau 4-dimensional vectors support (`luau-vector4` feature)
+- `Table::sequence_values()` iterator no longer uses any metamethods (`Table::raw_sequence_values()` is deprecated)
+- Added `Table:is_empty()` function that checks both hash and array parts
+- Refactored Debug interface
+- Re-exported `ffi` (`mlua-sys`) crate for easier writing of unsafe code
+- Refactored Lua 5.4 warnings interface
+- Take `&str` as function name in `TableExt` and `AnyUserDataExt` traits
+- Added module attribule `skip_memory_check` to improve performance
+- Added `AnyUserData::wrap()` to provide more easy way of creating _any_ userdata in Lua
+
 ## v0.9.0-beta.3
 
 - Added `OwnedAnyUserData::take()`

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mlua"
-version = "0.9.0-beta.3" # remember to update mlua_derive
+version = "0.9.0-rc.1" # remember to update mlua_derive
 authors = ["Aleksandr Orlenko <zxteam@pm.me>", "kyren <catherine@chucklefish.org>"]
 edition = "2021"
 repository = "https://github.com/khvzak/mlua"
@@ -33,6 +33,7 @@ luajit = ["ffi/luajit"]
 luajit52 = ["luajit", "ffi/luajit52"]
 luau = ["ffi/luau"]
 luau-jit = ["luau", "ffi/luau-codegen"]
+luau-vector4 = ["luau", "ffi/luau-vector4"]
 vendored = ["ffi/vendored"]
 module = ["mlua_derive", "ffi/module"]
 async = ["futures-util"]
@@ -42,7 +43,7 @@ macros = ["mlua_derive/macros"]
 unstable = []
 
 [dependencies]
-mlua_derive = { version = "=0.9.0-beta.2", optional = true, path = "mlua_derive" }
+mlua_derive = { version = "=0.9.0-rc.1", optional = true, path = "mlua_derive" }
 bstr = { version = "1.0", features = ["std"], default_features = false }
 once_cell = { version = "1.0" }
 num-traits = { version = "0.2.14" }
@@ -53,17 +54,16 @@ erased-serde = { version = "0.3", optional = true }
 serde-value = { version = "0.7", optional = true }
 parking_lot = { version = "0.12", optional = true }
 
-ffi = { package = "mlua-sys", version = "0.2.0", path = "mlua-sys" }
+ffi = { package = "mlua-sys", version = "0.2.1", path = "mlua-sys" }
 
 [dev-dependencies]
-rustyline = "11.0"
+rustyline = "12.0"
 criterion = { version = "0.5", features = ["async_tokio"] }
 trybuild = "1.0"
 futures = "0.3.5"
 hyper = { version = "0.14", features = ["client", "server"] }
 reqwest = { version = "0.11", features = ["json"] }
 tokio = { version = "1.0", features = ["full"] }
-futures-timer = "3.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 maplit = "1.0"

README.md

@@ -46,6 +46,7 @@ Below is a list of the available feature flags. By default `mlua` does not enabl
 * `luajit52`: activate [LuaJIT] support with partial compatibility with Lua 5.2
 * `luau`: activate [Luau] support (auto vendored mode)
 * `luau-jit`: activate [Luau] support with experimental jit backend. This is unstable feature and not recommended to use.
+* `luau-vector4`: activate [Luau] support with 4-dimensional vector.
 * `vendored`: build static Lua(JIT) library from sources during `mlua` compilation using [lua-src] or [luajit-src] crates
 * `module`: enable module mode (building loadable `cdylib` library for Lua)
 * `async`: enable async/await support (any executor can be used, eg. [tokio] or [async-std])

benches/benchmark.rs

@@ -264,17 +264,19 @@ fn call_userdata_method(c: &mut Criterion) {
 }
 
 fn call_async_userdata_method(c: &mut Criterion) {
-    #[derive(Clone, Copy)]
-    struct UserData(i64);
+    struct UserData(String);
+
     impl LuaUserData for UserData {
         fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
-            methods.add_async_method("method", |_, this, ()| async move { Ok(this.0) });
+            methods.add_async_method("method", |_, this, ()| async move { Ok(this.0.clone()) });
         }
     }
 
     let options = LuaOptions::new().thread_pool_size(1024);
     let lua = Lua::new_with(LuaStdLib::ALL_SAFE, options).unwrap();
-    lua.globals().set("userdata", UserData(10)).unwrap();
+    lua.globals()
+        .set("userdata", UserData("hello".to_string()))
+        .unwrap();
 
     c.bench_function("call async [userdata method] 10", |b| {
         let rt = Runtime::new().unwrap();

examples/async_http_client.rs

@@ -3,14 +3,13 @@ use std::collections::HashMap;
 use hyper::body::{Body as HyperBody, HttpBody as _};
 use hyper::Client as HyperClient;
 
-use mlua::{chunk, AnyUserData, ExternalResult, Lua, Result, UserData, UserDataMethods};
+use mlua::{chunk, ExternalResult, Lua, Result, UserData, UserDataMethods};
 
 struct BodyReader(HyperBody);
 
 impl UserData for BodyReader {
     fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
-        methods.add_async_function("read", |lua, reader: AnyUserData| async move {
-            let mut reader = reader.borrow_mut::<Self>()?;
+        methods.add_async_method_mut("read", |lua, reader, ()| async move {
             if let Some(bytes) = reader.0.data().await {
                 let bytes = bytes.into_lua_err()?;
                 return Some(lua.create_string(&bytes)).transpose();

examples/async_tcp_server.rs

@@ -6,9 +6,7 @@ use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::{TcpListener, TcpStream};
 use tokio::task;
 
-use mlua::{
-    chunk, AnyUserData, Function, Lua, RegistryKey, String as LuaString, UserData, UserDataMethods,
-};
+use mlua::{chunk, Function, Lua, RegistryKey, String as LuaString, UserData, UserDataMethods};
 
 struct LuaTcpStream(TcpStream);
 
@@ -18,28 +16,19 @@ impl UserData for LuaTcpStream {
             Ok(this.0.peer_addr()?.to_string())
         });
 
-        methods.add_async_function(
-            "read",
-            |lua, (this, size): (AnyUserData, usize)| async move {
-                let mut this = this.borrow_mut::<Self>()?;
-                let mut buf = vec![0; size];
-                let n = this.0.read(&mut buf).await?;
-                buf.truncate(n);
-                lua.create_string(&buf)
-            },
-        );
+        methods.add_async_method_mut("read", |lua, this, size| async move {
+            let mut buf = vec![0; size];
+            let n = this.0.read(&mut buf).await?;
+            buf.truncate(n);
+            lua.create_string(&buf)
+        });
 
-        methods.add_async_function(
-            "write",
-            |_, (this, data): (AnyUserData, LuaString)| async move {
-                let mut this = this.borrow_mut::<Self>()?;
-                let n = this.0.write(&data.as_bytes()).await?;
-                Ok(n)
-            },
-        );
+        methods.add_async_method_mut("write", |_, this, data: LuaString| async move {
+            let n = this.0.write(&data.as_bytes()).await?;
+            Ok(n)
+        });
 
-        methods.add_async_function("close", |_, this: AnyUserData| async move {
-            let mut this = this.borrow_mut::<Self>()?;
+        methods.add_async_method_mut("close", |_, this, ()| async move {
             this.0.shutdown().await?;
             Ok(())
         });

examples/repl.rs

@@ -1,11 +1,11 @@
 //! This example shows a simple read-evaluate-print-loop (REPL).
 
 use mlua::{Error, Lua, MultiValue};
-use rustyline::Editor;
+use rustyline::DefaultEditor;
 
 fn main() {
     let lua = Lua::new();
-    let mut editor = Editor::<(), _>::new().expect("Failed to make rustyline editor");
+    let mut editor = DefaultEditor::new().expect("Failed to create editor");
 
     loop {
         let mut prompt = "> ";
@@ -24,7 +24,7 @@ fn main() {
                         "{}",
                         values
                             .iter()
-                            .map(|value| format!("{:?}", value))
+                            .map(|value| format!("{:#?}", value))
                             .collect::<Vec<_>>()
                             .join("\t")
                     );

mlua-sys/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mlua-sys"
-version = "0.2.0"
+version = "0.2.1"
 authors = ["Aleksandr Orlenko <zxteam@pm.me>"]
 edition = "2021"
 repository = "https://github.com/khvzak/mlua"
@@ -27,6 +27,7 @@ luajit = []
 luajit52 = ["luajit"]
 luau = ["luau0-src"]
 luau-codegen = ["luau"]
+luau-vector4 = ["luau"]
 vendored = ["lua-src", "luajit-src"]
 module = []
 
@@ -37,5 +38,5 @@ cc = "1.0"
 cfg-if = "1.0"
 pkg-config = "0.3.17"
 lua-src = { version = ">= 546.0.0, < 550.0.0", optional = true }
-luajit-src = { version = ">= 210.4.0, < 220.0.0", optional = true }
-luau0-src = { version = "0.5.8", optional = true }
+luajit-src = { version = ">= 210.4.5, < 220.0.0", optional = true }
+luau0-src = { version = "0.5.11", optional = true }

mlua-sys/build/find_normal.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 use std::env;
 use std::ops::Bound;
 use std::path::PathBuf;

mlua-sys/build/find_vendored.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 use std::path::PathBuf;
 
 pub fn probe_lua() -> Option<PathBuf> {
@@ -23,6 +21,7 @@ pub fn probe_lua() -> Option<PathBuf> {
     #[cfg(feature = "luau")]
     let artifacts = luau0_src::Build::new()
         .enable_codegen(cfg!(feature = "luau-codegen"))
+        .set_vector_size(if cfg!(feature = "luau-vector4") { 4 } else { 3 })
         .build();
 
     artifacts.print_cargo_metadata();

mlua-sys/src/luau/lua.rs

@@ -156,7 +156,10 @@ extern "C" {
     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_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);
+    #[cfg(feature = "luau-vector4")]
+    pub fn lua_pushvector(L: *mut lua_State, x: c_float, y: c_float, z: c_float, w: c_float);
     #[link_name = "lua_pushlstring"]
     pub fn lua_pushlstring_(L: *mut lua_State, s: *const c_char, l: usize);
     #[link_name = "lua_pushstring"]

mlua_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mlua_derive"
-version = "0.9.0-beta.2"
+version = "0.9.0-rc.1"
 authors = ["Aleksandr Orlenko <zxteam@pm.me>"]
 edition = "2021"
 description = "Procedural macros for the mlua crate."
@@ -19,6 +19,6 @@ quote = "1.0"
 proc-macro2 = { version = "1.0", features = ["span-locations"] }
 proc-macro-error = { version = "1.0", optional = true }
 syn = { version = "2.0", features = ["full"] }
-itertools = { version = "0.10", optional = true }
+itertools = { version = "0.11", optional = true }
 regex = { version = "1.4", optional = true }
 once_cell = { version = "1.0", optional = true }

mlua_derive/src/lib.rs

@@ -13,6 +13,7 @@ use {
 #[derive(Default)]
 struct ModuleAttributes {
     name: Option<Ident>,
+    skip_memory_check: bool,
 }
 
 impl ModuleAttributes {
@@ -26,6 +27,11 @@ impl ModuleAttributes {
                     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"));
         }
@@ -45,6 +51,7 @@ pub fn lua_module(attr: TokenStream, item: TokenStream) -> TokenStream {
     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 = args.skip_memory_check;
 
     let wrapped = quote! {
         ::mlua::require_module_feature!();
@@ -53,7 +60,11 @@ pub fn lua_module(attr: TokenStream, item: TokenStream) -> TokenStream {
 
         #[no_mangle]
         unsafe extern "C" fn #ext_entrypoint_name(state: *mut ::mlua::lua_State) -> ::std::os::raw::c_int {
-            ::mlua::Lua::init_from_ptr(state)
+            let lua = ::mlua::Lua::init_from_ptr(state);
+            if #skip_memory_check {
+                lua.skip_memory_check(true);
+            }
+            lua
                 .entrypoint1(#func_name)
                 .expect("cannot initialize module")
         }

src/chunk.rs

@@ -11,9 +11,6 @@ use crate::lua::Lua;
 use crate::table::Table;
 use crate::value::{FromLuaMulti, IntoLua, IntoLuaMulti};
 
-#[cfg(feature = "async")]
-use futures_util::future::{self, LocalBoxFuture};
-
 /// Trait for types [loadable by Lua] and convertible to a [`Chunk`]
 ///
 /// [loadable by Lua]: https://www.lua.org/manual/5.4/manual.html#3.3.2
@@ -134,6 +131,14 @@ pub struct Compiler {
 #[cfg(any(feature = "luau", doc))]
 impl Default for Compiler {
     fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[cfg(any(feature = "luau", doc))]
+impl Compiler {
+    /// Creates Luau compiler instance with default options
+    pub const fn new() -> Self {
         // Defaults are taken from luacode.h
         Compiler {
             optimization_level: 1,
@@ -144,14 +149,6 @@ impl Default for Compiler {
             mutable_globals: Vec::new(),
         }
     }
-}
-
-#[cfg(any(feature = "luau", doc))]
-impl Compiler {
-    /// Creates Luau compiler instance with default options
-    pub fn new() -> Self {
-        Compiler::default()
-    }
 
     /// Sets Luau compiler optimization level.
     ///
@@ -159,7 +156,8 @@ impl Compiler {
     /// * 0 - no optimization
     /// * 1 - baseline optimization level that doesn't prevent debuggability (default)
     /// * 2 - includes optimizations that harm debuggability such as inlining
-    pub fn set_optimization_level(mut self, level: u8) -> Self {
+    #[must_use]
+    pub const fn set_optimization_level(mut self, level: u8) -> Self {
         self.optimization_level = level;
         self
     }
@@ -170,7 +168,8 @@ impl Compiler {
     /// * 0 - no debugging support
     /// * 1 - line info & function names only; sufficient for backtraces (default)
     /// * 2 - full debug info with local & upvalue names; necessary for debugger
-    pub fn set_debug_level(mut self, level: u8) -> Self {
+    #[must_use]
+    pub const fn set_debug_level(mut self, level: u8) -> Self {
         self.debug_level = level;
         self
     }
@@ -181,18 +180,21 @@ impl Compiler {
     /// * 0 - no code coverage support (default)
     /// * 1 - statement coverage
     /// * 2 - statement and expression coverage (verbose)
-    pub fn set_coverage_level(mut self, level: u8) -> Self {
+    #[must_use]
+    pub const fn set_coverage_level(mut self, level: u8) -> Self {
         self.coverage_level = level;
         self
     }
 
     #[doc(hidden)]
+    #[must_use]
     pub fn set_vector_lib(mut self, lib: Option<String>) -> Self {
         self.vector_lib = lib;
         self
     }
 
     #[doc(hidden)]
+    #[must_use]
     pub fn set_vector_ctor(mut self, ctor: Option<String>) -> Self {
         self.vector_ctor = ctor;
         self
@@ -201,6 +203,7 @@ impl Compiler {
     /// Sets a list of globals that are mutable.
     ///
     /// It disables the import optimization for fields accessed through these.
+    #[must_use]
     pub fn set_mutable_globals(mut self, globals: Vec<String>) -> Self {
         self.mutable_globals = globals;
         self
@@ -312,8 +315,8 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
     /// [`exec`]: #method.exec
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    pub fn exec_async(self) -> LocalBoxFuture<'lua, Result<()>> {
-        self.call_async(())
+    pub async fn exec_async(self) -> Result<()> {
+        self.call_async(()).await
     }
 
     /// Evaluate the chunk as either an expression or block.
@@ -344,17 +347,16 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
     /// [`eval`]: #method.eval
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    pub fn eval_async<'fut, R>(self) -> LocalBoxFuture<'fut, Result<R>>
+    pub async fn eval_async<R>(self) -> Result<R>
     where
-        'lua: 'fut,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
         if self.detect_mode() == ChunkMode::Binary {
-            self.call_async(())
+            self.call_async(()).await
         } else if let Ok(function) = self.to_expression() {
-            function.call_async(())
+            function.call_async(()).await
         } else {
-            self.call_async(())
+            self.call_async(()).await
         }
     }
 
@@ -374,16 +376,12 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
     /// [`call`]: #method.call
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    pub fn call_async<'fut, A, R>(self, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    pub async fn call_async<A, R>(self, args: A) -> Result<R>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
-        match self.into_function() {
-            Ok(func) => func.call_async(args),
-            Err(e) => Box::pin(future::err(e)),
-        }
+        self.into_function()?.call_async(args).await
     }
 
     /// Load this chunk into a regular `Function`.
@@ -470,7 +468,7 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
     fn to_expression(&self) -> Result<Function<'lua>> {
         // We assume that mode is Text
         let source = self.source.as_ref();
-        let source = source.map_err(|err| Error::RuntimeError(err.to_string()))?;
+        let source = source.map_err(Error::runtime)?;
         let source = Self::expression_source(source);
         // We don't need to compile source if no compiler options set
         #[cfg(feature = "luau")]
@@ -504,7 +502,7 @@ impl<'lua, 'a> Chunk<'lua, 'a> {
     }
 
     fn convert_name(name: String) -> Result<CString> {
-        CString::new(name).map_err(|err| Error::RuntimeError(format!("invalid name: {err}")))
+        CString::new(name).map_err(|err| Error::runtime(format!("invalid name: {err}")))
     }
 
     fn expression_source(source: &[u8]) -> Vec<u8> {

src/conversion.rs

@@ -52,7 +52,7 @@ impl<'lua> FromLua<'lua> for String<'lua> {
         lua.coerce_string(value)?
             .ok_or_else(|| Error::FromLuaConversionError {
                 from: ty,
-                to: "String",
+                to: "string",
                 message: Some("expected string or number".to_string()),
             })
     }
@@ -211,7 +211,7 @@ impl<'lua> FromLua<'lua> for OwnedAnyUserData {
     }
 }
 
-impl<'lua, T: 'static + MaybeSend + UserData> IntoLua<'lua> for T {
+impl<'lua, T: UserData + MaybeSend + 'static> IntoLua<'lua> for T {
     #[inline]
     fn into_lua(self, lua: &'lua Lua) -> Result<Value<'lua>> {
         Ok(Value::UserData(lua.create_userdata(self)?))
@@ -244,7 +244,7 @@ impl<'lua> FromLua<'lua> for Error {
     fn from_lua(value: Value<'lua>, lua: &'lua Lua) -> Result<Error> {
         match value {
             Value::Error(err) => Ok(err),
-            val => Ok(Error::RuntimeError(
+            val => Ok(Error::runtime(
                 lua.coerce_string(val)?
                     .and_then(|s| Some(s.to_str().ok()?.to_owned()))
                     .unwrap_or_else(|| "<unprintable error>".to_owned()),
@@ -292,6 +292,29 @@ impl<'lua> FromLua<'lua> for LightUserData {
     }
 }
 
+#[cfg(feature = "luau")]
+impl<'lua> IntoLua<'lua> for crate::types::Vector {
+    #[inline]
+    fn into_lua(self, _: &'lua Lua) -> Result<Value<'lua>> {
+        Ok(Value::Vector(self))
+    }
+}
+
+#[cfg(feature = "luau")]
+impl<'lua> FromLua<'lua> for crate::types::Vector {
+    #[inline]
+    fn from_lua(value: Value<'lua>, _: &'lua Lua) -> Result<Self> {
+        match value {
+            Value::Vector(v) => Ok(v),
+            _ => Err(Error::FromLuaConversionError {
+                from: value.type_name(),
+                to: "vector",
+                message: None,
+            }),
+        }
+    }
+}
+
 impl<'lua> IntoLua<'lua> for StdString {
     #[inline]
     fn into_lua(self, lua: &'lua Lua) -> Result<Value<'lua>> {
@@ -412,7 +435,7 @@ impl<'lua> FromLua<'lua> for BString {
             lua.coerce_string(value)?
                 .ok_or_else(|| Error::FromLuaConversionError {
                     from: ty,
-                    to: "String",
+                    to: "BString",
                     message: Some("expected string or number".to_string()),
                 })?
                 .as_bytes()
@@ -533,7 +556,7 @@ lua_convert_float!(f64);
 
 impl<'lua, T> IntoLua<'lua> for &[T]
 where
-    T: Clone + IntoLua<'lua>,
+    T: IntoLua<'lua> + Clone,
 {
     #[inline]
     fn into_lua(self, lua: &'lua Lua) -> Result<Value<'lua>> {
@@ -561,21 +584,22 @@ where
     fn from_lua(value: Value<'lua>, _lua: &'lua Lua) -> Result<Self> {
         match value {
             #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) if N == 3 => Ok(mlua_expect!(
-                vec![
-                    T::from_lua(Value::Number(x as _), _lua)?,
-                    T::from_lua(Value::Number(y as _), _lua)?,
-                    T::from_lua(Value::Number(z as _), _lua)?,
-                ]
-                .try_into()
-                .map_err(|_| ()),
-                "cannot convert vector to array"
-            )),
+            #[rustfmt::skip]
+            Value::Vector(v) if N == crate::types::Vector::SIZE => unsafe {
+                use std::{mem, ptr};
+                let mut arr: [mem::MaybeUninit<T>; N] = mem::MaybeUninit::uninit().assume_init();
+                ptr::write(arr[0].as_mut_ptr() , T::from_lua(Value::Number(v.x() as _), _lua)?);
+                ptr::write(arr[1].as_mut_ptr(), T::from_lua(Value::Number(v.y() as _), _lua)?);
+                ptr::write(arr[2].as_mut_ptr(), T::from_lua(Value::Number(v.z() as _), _lua)?);
+                #[cfg(feature = "luau-vector4")]
+                ptr::write(arr[3].as_mut_ptr(), T::from_lua(Value::Number(v.w() as _), _lua)?);
+                Ok(mem::transmute_copy(&arr))
+            },
             Value::Table(table) => {
                 let vec = table.sequence_values().collect::<Result<Vec<_>>>()?;
                 vec.try_into()
                     .map_err(|vec: Vec<T>| Error::FromLuaConversionError {
-                        from: "Table",
+                        from: "table",
                         to: "Array",
                         message: Some(format!("expected table of length {}, got {}", N, vec.len())),
                     })
@@ -614,12 +638,6 @@ impl<'lua, T: FromLua<'lua>> FromLua<'lua> for Vec<T> {
     #[inline]
     fn from_lua(value: Value<'lua>, _lua: &'lua Lua) -> Result<Self> {
         match value {
-            #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) => Ok(vec![
-                T::from_lua(Value::Number(x as _), _lua)?,
-                T::from_lua(Value::Number(y as _), _lua)?,
-                T::from_lua(Value::Number(z as _), _lua)?,
-            ]),
             Value::Table(table) => table.sequence_values().collect(),
             _ => Err(Error::FromLuaConversionError {
                 from: value.type_name(),
@@ -691,7 +709,7 @@ impl<'lua, T: Eq + Hash + FromLua<'lua>, S: BuildHasher + Default> FromLua<'lua>
     #[inline]
     fn from_lua(value: Value<'lua>, _: &'lua Lua) -> Result<Self> {
         match value {
-            Value::Table(table) if table.len()? > 0 => table.sequence_values().collect(),
+            Value::Table(table) if table.raw_len() > 0 => table.sequence_values().collect(),
             Value::Table(table) => table
                 .pairs::<T, Value<'lua>>()
                 .map(|res| res.map(|(k, _)| k))
@@ -718,7 +736,7 @@ impl<'lua, T: Ord + FromLua<'lua>> FromLua<'lua> for BTreeSet<T> {
     #[inline]
     fn from_lua(value: Value<'lua>, _: &'lua Lua) -> Result<Self> {
         match value {
-            Value::Table(table) if table.len()? > 0 => table.sequence_values().collect(),
+            Value::Table(table) if table.raw_len() > 0 => table.sequence_values().collect(),
             Value::Table(table) => table
                 .pairs::<T, Value<'lua>>()
                 .map(|res| res.map(|(k, _)| k))

src/error.rs

@@ -47,11 +47,6 @@ pub enum Error {
     /// This error can only happen when Lua state was not created by us and does not have the
     /// custom allocator attached.
     MemoryLimitNotAvailable,
-    /// Main thread is not available.
-    ///
-    /// This error can only happen in Lua5.1/LuaJIT module mode, when module loaded within a coroutine.
-    /// These Lua versions does not have `LUA_RIDX_MAINTHREAD` registry key.
-    MainThreadNotAvailable,
     /// A mutable callback has triggered Lua code that has called the same mutable callback again.
     ///
     /// This is an error because a mutable callback can only be borrowed mutably once.
@@ -69,7 +64,7 @@ pub enum Error {
     /// called with a huge number of arguments, or a rust callback returns a huge number of return
     /// values.
     StackError,
-    /// Too many arguments to `Function::bind`
+    /// Too many arguments to `Function::bind`.
     BindError,
     /// Bad argument received from Lua (usually when calling a function).
     ///
@@ -130,7 +125,7 @@ pub enum Error {
     ///
     /// [`AnyUserData`]: crate::AnyUserData
     UserDataDestructed,
-    /// An [`AnyUserData`] immutable borrow failed because it is already borrowed mutably.
+    /// An [`AnyUserData`] immutable borrow failed.
     ///
     /// This error can occur when a method on a [`UserData`] type calls back into Lua, which then
     /// tries to call a method on the same [`UserData`] type. Consider restructuring your API to
@@ -139,7 +134,7 @@ pub enum Error {
     /// [`AnyUserData`]: crate::AnyUserData
     /// [`UserData`]: crate::UserData
     UserDataBorrowError,
-    /// An [`AnyUserData`] mutable borrow failed because it is already borrowed.
+    /// An [`AnyUserData`] mutable borrow failed.
     ///
     /// This error can occur when a method on a [`UserData`] type calls back into Lua, which then
     /// tries to call a method on the same [`UserData`] type. Consider restructuring your API to
@@ -226,9 +221,6 @@ impl fmt::Display for Error {
             Error::MemoryLimitNotAvailable => {
                 write!(fmt, "setting memory limit is not available")
             }
-            Error::MainThreadNotAvailable => {
-                write!(fmt, "main thread is not available in Lua 5.1")
-            }
             Error::RecursiveMutCallback => write!(fmt, "mutable callback called recursively"),
             Error::CallbackDestructed => write!(
                 fmt,
@@ -270,8 +262,8 @@ impl fmt::Display for Error {
             Error::CoroutineInactive => write!(fmt, "cannot resume inactive coroutine"),
             Error::UserDataTypeMismatch => write!(fmt, "userdata is not expected type"),
             Error::UserDataDestructed => write!(fmt, "userdata has been destructed"),
-            Error::UserDataBorrowError => write!(fmt, "userdata already mutably borrowed"),
-            Error::UserDataBorrowMutError => write!(fmt, "userdata already borrowed"),
+            Error::UserDataBorrowError => write!(fmt, "error borrowing userdata"),
+            Error::UserDataBorrowMutError => write!(fmt, "error mutably borrowing userdata"),
             Error::MetaMethodRestricted(ref method) => write!(fmt, "metamethod {method} is restricted"),
             Error::MetaMethodTypeError { ref method, type_name, ref message } => {
                 write!(fmt, "metamethod {method} has unsupported type {type_name}")?;
@@ -345,7 +337,14 @@ impl StdError for Error {
 }
 
 impl Error {
+    /// Creates a new `RuntimeError` with the given message.
+    #[inline]
+    pub fn runtime<S: fmt::Display>(message: S) -> Self {
+        Error::RuntimeError(message.to_string())
+    }
+
     /// Wraps an external error object.
+    #[inline]
     pub fn external<T: Into<Box<dyn StdError + Send + Sync>>>(err: T) -> Self {
         Error::ExternalError(err.into().into())
     }
@@ -387,6 +386,7 @@ impl Error {
     }
 }
 
+/// Trait for converting [`std::error::Error`] into Lua [`Error`].
 pub trait ExternalError {
     fn into_lua_err(self) -> Error;
 }
@@ -397,6 +397,7 @@ impl<E: Into<Box<dyn StdError + Send + Sync>>> ExternalError for E {
     }
 }
 
+/// Trait for converting [`std::result::Result`] into Lua [`Result`].
 pub trait ExternalResult<T> {
     fn into_lua_err(self) -> Result<T>;
 }

src/function.rs

@@ -10,14 +10,15 @@ use crate::memory::MemoryState;
 use crate::table::Table;
 use crate::types::{Callback, LuaRef, MaybeSend};
 use crate::util::{
-    assert_stack, check_stack, error_traceback, pop_error, ptr_to_cstr_bytes, StackGuard,
+    assert_stack, check_stack, error_traceback, linenumber_to_usize, pop_error, ptr_to_lossy_str,
+    ptr_to_str, StackGuard,
 };
 use crate::value::{FromLuaMulti, IntoLua, IntoLuaMulti};
 
 #[cfg(feature = "async")]
 use {
     crate::types::AsyncCallback,
-    futures_util::future::{self, Future, LocalBoxFuture, TryFutureExt},
+    futures_util::future::{self, Future},
 };
 
 /// Handle to an internal Lua function.
@@ -52,24 +53,22 @@ impl OwnedFunction {
 /// [`Lua Debug Interface`]: https://www.lua.org/manual/5.4/manual.html#4.7
 #[derive(Clone, Debug)]
 pub struct FunctionInfo {
-    /// A (reasonable) name of the function.
+    /// A (reasonable) name of the function (`None` if the name cannot be found).
     pub name: Option<String>,
-    /// Explains the `name` field ("global", "local", "method", "field", "upvalue", or "").
+    /// Explains the `name` field (can be `global`/`local`/`method`/`field`/`upvalue`/etc).
     ///
     /// Always `None` for Luau.
-    pub name_what: Option<String>,
-    /// A string "Lua" if the function is a Lua function, "C" if it is a C function, "main" if it is the main part of a chunk.
-    pub what: Option<String>,
-    /// The source of the chunk that created the function.
-    pub source: Option<Vec<u8>>,
-    /// A "printable" version of source, to be used in error messages.
-    pub short_src: Option<Vec<u8>>,
+    pub name_what: Option<&'static str>,
+    /// A string `Lua` if the function is a Lua function, `C` if it is a C function, `main` if it is the main part of a chunk.
+    pub what: &'static str,
+    /// Source of the chunk that created the function.
+    pub source: Option<String>,
+    /// A "printable" version of `source`, to be used in error messages.
+    pub short_src: Option<String>,
     /// The line number where the definition of the function starts.
-    pub line_defined: i32,
-    /// The line number where the definition of the function ends.
-    ///
-    /// Always `-1` for Luau.
-    pub last_line_defined: i32,
+    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>,
 }
 
 /// Luau function coverage snapshot.
@@ -77,7 +76,7 @@ pub struct FunctionInfo {
 #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct CoverageInfo {
-    pub function: Option<std::string::String>,
+    pub function: Option<String>,
     pub line_defined: i32,
     pub depth: i32,
     pub hits: Vec<i32>,
@@ -168,14 +167,13 @@ impl<'lua> Function<'lua> {
     ///
     /// ```
     /// use std::time::Duration;
-    /// use futures_timer::Delay;
     /// # use mlua::{Lua, Result};
     /// # #[tokio::main]
     /// # async fn main() -> Result<()> {
     /// # let lua = Lua::new();
     ///
     /// let sleep = lua.create_async_function(move |_lua, n: u64| async move {
-    ///     Delay::new(Duration::from_millis(n)).await;
+    ///     tokio::time::sleep(Duration::from_millis(n)).await;
     ///     Ok(())
     /// })?;
     ///
@@ -188,21 +186,18 @@ impl<'lua> Function<'lua> {
     /// [`AsyncThread`]: crate::AsyncThread
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    pub fn call_async<'fut, A, R>(&self, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    pub fn call_async<A, R>(&self, args: A) -> impl Future<Output = Result<R>> + 'lua
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
         let lua = self.0.lua;
-        match lua.create_recycled_thread(self) {
-            Ok(t) => {
-                let mut t = t.into_async(args);
-                t.set_recyclable(true);
-                Box::pin(t)
-            }
-            Err(e) => Box::pin(future::err(e)),
-        }
+        let thread_res = lua.create_recycled_thread(self).map(|th| {
+            let mut th = th.into_async(args);
+            th.set_recyclable(true);
+            th
+        });
+        async move { thread_res?.await }
     }
 
     /// Returns a function that, when called, calls `self`, passing `args` as the first set of
@@ -303,17 +298,7 @@ impl<'lua> Function<'lua> {
             assert_stack(state, 1);
 
             lua.push_ref(&self.0);
-
-            let mut ar: ffi::lua_Debug = mem::zeroed();
-            #[cfg(not(feature = "luau"))]
-            {
-                ffi::lua_pushvalue(state, -1);
-                ffi::lua_getinfo(state, cstr!(">S"), &mut ar);
-            }
-            #[cfg(feature = "luau")]
-            ffi::lua_getinfo(state, -1, cstr!("s"), &mut ar);
-
-            if ptr_to_cstr_bytes(ar.what) == Some(b"C") {
+            if ffi::lua_iscfunction(state, -1) != 0 {
                 return None;
             }
 
@@ -350,17 +335,7 @@ impl<'lua> Function<'lua> {
             check_stack(state, 2)?;
 
             lua.push_ref(&self.0);
-
-            let mut ar: ffi::lua_Debug = mem::zeroed();
-            #[cfg(not(feature = "luau"))]
-            {
-                ffi::lua_pushvalue(state, -1);
-                ffi::lua_getinfo(state, cstr!(">S"), &mut ar);
-            }
-            #[cfg(feature = "luau")]
-            ffi::lua_getinfo(state, -1, cstr!("s"), &mut ar);
-
-            if ptr_to_cstr_bytes(ar.what) == Some(b"C") {
+            if ffi::lua_iscfunction(state, -1) != 0 {
                 return Ok(false);
             }
 
@@ -414,23 +389,25 @@ impl<'lua> Function<'lua> {
             mlua_assert!(res != 0, "lua_getinfo failed with `>Sn`");
 
             FunctionInfo {
-                name: ptr_to_cstr_bytes(ar.name).map(|s| String::from_utf8_lossy(s).into_owned()),
+                name: ptr_to_lossy_str(ar.name).map(|s| s.into_owned()),
                 #[cfg(not(feature = "luau"))]
-                name_what: ptr_to_cstr_bytes(ar.namewhat)
-                    .map(|s| String::from_utf8_lossy(s).into_owned()),
+                name_what: match ptr_to_str(ar.namewhat) {
+                    Some("") => None,
+                    val => val,
+                },
                 #[cfg(feature = "luau")]
                 name_what: None,
-                what: ptr_to_cstr_bytes(ar.what).map(|s| String::from_utf8_lossy(s).into_owned()),
-                source: ptr_to_cstr_bytes(ar.source).map(|s| s.to_vec()),
+                what: ptr_to_str(ar.what).unwrap_or("main"),
+                source: ptr_to_lossy_str(ar.source).map(|s| s.into_owned()),
                 #[cfg(not(feature = "luau"))]
-                short_src: ptr_to_cstr_bytes(ar.short_src.as_ptr()).map(|s| s.to_vec()),
+                short_src: ptr_to_lossy_str(ar.short_src.as_ptr()).map(|s| s.into_owned()),
                 #[cfg(feature = "luau")]
-                short_src: ptr_to_cstr_bytes(ar.short_src).map(|s| s.to_vec()),
-                line_defined: ar.linedefined,
+                short_src: ptr_to_lossy_str(ar.short_src).map(|s| s.into_owned()),
+                line_defined: linenumber_to_usize(ar.linedefined),
                 #[cfg(not(feature = "luau"))]
-                last_line_defined: ar.lastlinedefined,
+                last_line_defined: linenumber_to_usize(ar.lastlinedefined),
                 #[cfg(feature = "luau")]
-                last_line_defined: -1,
+                last_line_defined: None,
             }
         }
     }
@@ -484,7 +461,7 @@ impl<'lua> Function<'lua> {
     /// Requires `feature = "luau"`
     ///
     /// [`Compiler::set_coverage_level`]: crate::chunk::Compiler::set_coverage_level
-    #[cfg(any(feature = "luau", docsrs))]
+    #[cfg(any(feature = "luau", doc))]
     #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
     pub fn coverage<F>(&self, mut func: F)
     where
@@ -564,12 +541,12 @@ impl OwnedFunction {
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
     #[inline]
-    pub fn call_async<'lua, A, R>(&'lua self, args: A) -> LocalBoxFuture<'lua, Result<R>>
+    pub async fn call_async<'lua, A, R>(&'lua self, args: A) -> Result<R>
     where
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua> + 'lua,
     {
-        self.to_ref().call_async(args)
+        self.to_ref().call_async(args).await
     }
 }
 
@@ -624,7 +601,8 @@ impl<'lua> Function<'lua> {
                 Ok(args) => args,
                 Err(e) => return Box::pin(future::err(e)),
             };
-            Box::pin(func(lua, args).and_then(move |ret| future::ready(ret.into_lua_multi(lua))))
+            let fut = func(lua, args);
+            Box::pin(async move { fut.await?.into_lua_multi(lua) })
         }))
     }
 }

src/hook.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::cell::UnsafeCell;
 #[cfg(not(feature = "luau"))]
 use std::ops::{BitOr, BitOrAssign};
@@ -6,7 +7,7 @@ use std::os::raw::c_int;
 use ffi::lua_Debug;
 
 use crate::lua::Lua;
-use crate::util::ptr_to_cstr_bytes;
+use crate::util::{linenumber_to_usize, ptr_to_lossy_str, ptr_to_str};
 
 /// Contains information about currently executing Lua code.
 ///
@@ -78,9 +79,12 @@ impl<'lua> Debug<'lua> {
             );
 
             DebugNames {
-                name: ptr_to_cstr_bytes((*self.ar.get()).name),
+                name: ptr_to_lossy_str((*self.ar.get()).name),
                 #[cfg(not(feature = "luau"))]
-                name_what: ptr_to_cstr_bytes((*self.ar.get()).namewhat),
+                name_what: match ptr_to_str((*self.ar.get()).namewhat) {
+                    Some("") => None,
+                    val => val,
+                },
                 #[cfg(feature = "luau")]
                 name_what: None,
             }
@@ -102,15 +106,17 @@ impl<'lua> Debug<'lua> {
             );
 
             DebugSource {
-                source: ptr_to_cstr_bytes((*self.ar.get()).source),
+                source: ptr_to_lossy_str((*self.ar.get()).source),
                 #[cfg(not(feature = "luau"))]
-                short_src: ptr_to_cstr_bytes((*self.ar.get()).short_src.as_ptr()),
+                short_src: ptr_to_lossy_str((*self.ar.get()).short_src.as_ptr()),
                 #[cfg(feature = "luau")]
-                short_src: ptr_to_cstr_bytes((*self.ar.get()).short_src),
-                line_defined: (*self.ar.get()).linedefined,
+                short_src: ptr_to_lossy_str((*self.ar.get()).short_src),
+                line_defined: linenumber_to_usize((*self.ar.get()).linedefined),
                 #[cfg(not(feature = "luau"))]
-                last_line_defined: (*self.ar.get()).lastlinedefined,
-                what: ptr_to_cstr_bytes((*self.ar.get()).what),
+                last_line_defined: linenumber_to_usize((*self.ar.get()).lastlinedefined),
+                #[cfg(feature = "luau")]
+                last_line_defined: None,
+                what: ptr_to_str((*self.ar.get()).what).unwrap_or("main"),
             }
         }
     }
@@ -210,18 +216,26 @@ pub enum DebugEvent {
 
 #[derive(Clone, Debug)]
 pub struct DebugNames<'a> {
-    pub name: Option<&'a [u8]>,
-    pub name_what: Option<&'a [u8]>,
+    /// A (reasonable) name of the function (`None` if the name cannot be found).
+    pub name: Option<Cow<'a, str>>,
+    /// Explains the `name` field (can be `global`/`local`/`method`/`field`/`upvalue`/etc).
+    ///
+    /// Always `None` for Luau.
+    pub name_what: Option<&'static str>,
 }
 
 #[derive(Clone, Debug)]
 pub struct DebugSource<'a> {
-    pub source: Option<&'a [u8]>,
-    pub short_src: Option<&'a [u8]>,
-    pub line_defined: i32,
-    #[cfg(not(feature = "luau"))]
-    pub last_line_defined: i32,
-    pub what: Option<&'a [u8]>,
+    /// Source of the chunk that created the function.
+    pub source: Option<Cow<'a, str>>,
+    /// A "printable" version of `source`, to be used in error messages.
+    pub short_src: Option<Cow<'a, str>>,
+    /// The line number where the definition of the function starts.
+    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>,
+    /// A string `Lua` if the function is a Lua function, `C` if it is a C function, `main` if it is the main part of a chunk.
+    pub what: &'static str,
 }
 
 #[derive(Copy, Clone, Debug)]

src/lib.rs

@@ -103,7 +103,7 @@ mod value;
 
 pub mod prelude;
 
-pub use ffi::{lua_CFunction, lua_State};
+pub use ffi::{self, lua_CFunction, lua_State};
 
 pub use crate::chunk::{AsChunk, Chunk, ChunkMode};
 pub use crate::error::{Error, ErrorContext, ExternalError, ExternalResult, Result};
@@ -122,7 +122,7 @@ pub use crate::userdata::{
     UserDataRef, UserDataRefMut,
 };
 pub use crate::userdata_ext::AnyUserDataExt;
-pub use crate::userdata_impl::UserDataRegistrar;
+pub use crate::userdata_impl::UserDataRegistry;
 pub use crate::value::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, MultiValue, Nil, Value};
 
 #[cfg(not(feature = "luau"))]
@@ -130,7 +130,11 @@ pub use crate::hook::HookTriggers;
 
 #[cfg(any(feature = "luau", doc))]
 #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
-pub use crate::{chunk::Compiler, function::CoverageInfo, types::VmState};
+pub use crate::{
+    chunk::Compiler,
+    function::CoverageInfo,
+    types::{Vector, VmState},
+};
 
 #[cfg(feature = "async")]
 pub use crate::thread::AsyncThread;
@@ -231,7 +235,7 @@ pub use mlua_derive::chunk;
 ///
 /// You can also pass options to the attribute:
 ///
-/// name - name of the module, defaults to the name of the function
+/// * name - name of the module, defaults to the name of the function
 ///
 /// ```ignore
 /// #[mlua::lua_module(name = "alt_module")]
@@ -240,6 +244,20 @@ pub use mlua_derive::chunk;
 /// }
 /// ```
 ///
+/// * 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 mode 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> {
+///     ...
+/// }
+/// ```
+///
 #[cfg(any(feature = "module", docsrs))]
 #[cfg_attr(docsrs, doc(cfg(feature = "module")))]
 pub use mlua_derive::lua_module;

src/lua.rs

@@ -30,7 +30,7 @@ use crate::types::{
     LightUserData, LuaRef, MaybeSend, Number, RegistryKey,
 };
 use crate::userdata::{AnyUserData, MetaMethod, UserData, UserDataCell};
-use crate::userdata_impl::{UserDataProxy, UserDataRegistrar};
+use crate::userdata_impl::{UserDataProxy, UserDataRegistry};
 use crate::util::{
     self, assert_stack, check_stack, get_destructed_userdata_metatable, get_gc_metatable,
     get_gc_userdata, get_main_state, get_userdata, init_error_registry, init_gc_metatable,
@@ -50,12 +50,15 @@ use crate::{hook::HookTriggers, types::HookCallback};
 #[cfg(feature = "luau")]
 use crate::types::InterruptCallback;
 #[cfg(any(feature = "luau", doc))]
-use crate::{chunk::Compiler, types::VmState};
+use crate::{
+    chunk::Compiler,
+    types::{Vector, VmState},
+};
 
 #[cfg(feature = "async")]
 use {
     crate::types::{AsyncCallback, AsyncCallbackUpvalue, AsyncPollUpvalue},
-    futures_util::future::{self, Future, TryFutureExt},
+    futures_util::future::{self, Future},
     futures_util::task::{noop_waker_ref, Context, Poll, Waker},
 };
 
@@ -92,7 +95,10 @@ pub(crate) struct ExtraData {
     safe: bool,
     libs: StdLib,
     mem_state: Option<NonNull<MemoryState>>,
+    #[cfg(feature = "module")]
+    skip_memory_check: bool,
 
+    // Auxiliary thread to store references
     ref_thread: *mut ffi::lua_State,
     ref_stack_size: c_int,
     ref_stack_top: c_int,
@@ -445,7 +451,7 @@ impl Lua {
     ///
     /// Once called, a returned Lua state is cached in the registry and can be retrieved
     /// by calling this function again.
-    #[allow(clippy::missing_safety_doc)]
+    #[allow(clippy::missing_safety_doc, clippy::arc_with_non_send_sync)]
     pub unsafe fn init_from_ptr(state: *mut ffi::lua_State) -> Lua {
         assert!(!state.is_null(), "Lua state is NULL");
         if let Some(lua) = Lua::try_from_ptr(state) {
@@ -511,6 +517,8 @@ impl Lua {
             safe: false,
             libs: StdLib::NONE,
             mem_state: None,
+            #[cfg(feature = "module")]
+            skip_memory_check: false,
             ref_thread,
             // We need 1 extra stack space to move values in and out of the ref stack.
             ref_stack_size: ffi::LUA_MINSTACK - 1,
@@ -694,8 +702,6 @@ impl Lua {
     ///
     /// This function is useful when the `Lua` object is supposed to live for the remainder
     /// of the program's life.
-    /// In particular in asynchronous context this will allow to spawn Lua tasks to execute
-    /// in background.
     ///
     /// Dropping the returned reference will cause a memory leak. If this is not acceptable,
     /// the reference should first be wrapped with the [`Lua::from_static`] function producing a `Lua`.
@@ -724,7 +730,7 @@ impl Lua {
     where
         A: FromLuaMulti<'lua>,
         R: IntoLua<'lua>,
-        F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>,
+        F: Fn(&'lua Lua, A) -> Result<R> + MaybeSend + 'static,
     {
         let entrypoint_inner = |lua: &'lua Lua, func: F| {
             let state = lua.state();
@@ -766,11 +772,18 @@ impl Lua {
     pub unsafe fn entrypoint1<'lua, R, F>(self, func: F) -> Result<c_int>
     where
         R: IntoLua<'lua>,
-        F: 'static + MaybeSend + Fn(&'lua Lua) -> Result<R>,
+        F: Fn(&'lua Lua) -> Result<R> + MaybeSend + 'static,
     {
         self.entrypoint(move |lua, _: ()| func(lua))
     }
 
+    /// Skips memory checks for some operations.
+    #[doc(hidden)]
+    #[cfg(feature = "module")]
+    pub fn skip_memory_check(&self, skip: bool) {
+        unsafe { (*self.extra.get()).skip_memory_check = skip };
+    }
+
     /// Enables (or disables) sandbox mode on this Lua instance.
     ///
     /// This method, in particular:
@@ -833,8 +846,8 @@ impl Lua {
     /// limited form of execution limits by setting [`HookTriggers.every_nth_instruction`] and
     /// erroring once an instruction limit has been reached.
     ///
-    /// This method sets a hook function for the main thread (if available) of this Lua instance.
-    /// If you want to set a hook function for a thread (coroutine), use [`Thread::set_hook()`] instead.
+    /// This method sets a hook function for the current thread of this Lua instance.
+    /// If you want to set a hook function for another thread (coroutine), use [`Thread::set_hook()`] instead.
     ///
     /// Please note you cannot have more than one hook function set at a time for this Lua instance.
     ///
@@ -849,7 +862,7 @@ impl Lua {
     /// lua.set_hook(HookTriggers::EVERY_LINE, |_lua, debug| {
     ///     println!("line {}", debug.curr_line());
     ///     Ok(())
-    /// })?;
+    /// });
     ///
     /// lua.load(r#"
     ///     local x = 2 + 3
@@ -863,15 +876,11 @@ impl Lua {
     /// [`HookTriggers.every_nth_instruction`]: crate::HookTriggers::every_nth_instruction
     #[cfg(not(feature = "luau"))]
     #[cfg_attr(docsrs, doc(cfg(not(feature = "luau"))))]
-    pub fn set_hook<F>(&self, triggers: HookTriggers, callback: F) -> Result<()>
+    pub fn set_hook<F>(&self, triggers: HookTriggers, callback: F)
     where
         F: Fn(&Lua, Debug) -> Result<()> + MaybeSend + 'static,
     {
-        unsafe {
-            let state = get_main_state(self.main_state).ok_or(Error::MainThreadNotAvailable)?;
-            self.set_thread_hook(state, triggers, callback);
-        }
-        Ok(())
+        unsafe { self.set_thread_hook(self.state(), triggers, callback) };
     }
 
     /// Sets a 'hook' function for a thread (coroutine).
@@ -1028,7 +1037,7 @@ impl Lua {
     #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
     pub fn set_warning_function<F>(&self, callback: F)
     where
-        F: 'static + MaybeSend + Fn(&Lua, &CStr, bool) -> Result<()>,
+        F: Fn(&Lua, &str, bool) -> Result<()> + MaybeSend + 'static,
     {
         unsafe extern "C" fn warn_proc(ud: *mut c_void, msg: *const c_char, tocont: c_int) {
             let extra = ud as *mut ExtraData;
@@ -1038,8 +1047,8 @@ impl Lua {
                     (*extra).warn_callback.as_ref(),
                     "no warning callback set in warn_proc"
                 );
-                let msg = CStr::from_ptr(msg);
-                cb(lua, msg, tocont != 0)
+                let msg = std::string::String::from_utf8_lossy(CStr::from_ptr(msg).to_bytes());
+                cb(lua, &msg, tocont != 0)
             });
         }
 
@@ -1066,15 +1075,25 @@ impl Lua {
 
     /// Emits a warning with the given message.
     ///
-    /// A message in a call with `tocont` set to `true` should be continued in another call to this function.
+    /// A message in a call with `incomplete` set to `true` should be continued in
+    /// another call to this function.
     ///
     /// Requires `feature = "lua54"`
     #[cfg(feature = "lua54")]
     #[cfg_attr(docsrs, doc(cfg(feature = "lua54")))]
-    pub fn warning<S: Into<Vec<u8>>>(&self, msg: S, tocont: bool) -> Result<()> {
-        let msg = CString::new(msg).map_err(|err| Error::RuntimeError(err.to_string()))?;
-        unsafe { ffi::lua_warning(self.state(), msg.as_ptr(), tocont as c_int) };
-        Ok(())
+    pub fn warning(&self, msg: impl AsRef<str>, incomplete: bool) {
+        let msg = msg.as_ref();
+        let mut bytes = vec![0; msg.len() + 1];
+        bytes[..msg.len()].copy_from_slice(msg.as_bytes());
+        let real_len = bytes.iter().position(|&c| c == 0).unwrap();
+        bytes.truncate(real_len);
+        unsafe {
+            ffi::lua_warning(
+                self.state(),
+                bytes.as_ptr() as *const c_char,
+                incomplete as c_int,
+            );
+        }
     }
 
     /// Gets information about the interpreter runtime stack.
@@ -1121,7 +1140,7 @@ impl Lua {
     /// a `Error::MemoryError` is generated instead.
     /// Returns previous limit (zero means no limit).
     ///
-    /// Does not work on module mode where Lua state is managed externally.
+    /// Does not work in module mode where Lua state is managed externally.
     pub fn set_memory_limit(&self, limit: usize) -> Result<usize> {
         unsafe {
             match (*self.extra.get()).mem_state.map(|mut x| x.as_mut()) {
@@ -1300,7 +1319,7 @@ impl Lua {
     ///
     /// By default JIT is enabled. Changing this option does not have any effect on
     /// already loaded functions.
-    #[cfg(any(feature = "luau-jit", docsrs))]
+    #[cfg(any(feature = "luau-jit", doc))]
     #[cfg_attr(docsrs, doc(cfg(feature = "luau-jit")))]
     pub fn enable_jit(&self, enable: bool) {
         unsafe { (*self.extra.get()).enable_jit = enable };
@@ -1400,7 +1419,7 @@ impl Lua {
     /// `narr` is a hint for how many elements the table will have as a sequence;
     /// `nrec` is a hint for how many other elements the table will have.
     /// Lua may use these hints to preallocate memory for the new table.
-    pub fn create_table_with_capacity(&self, narr: c_int, nrec: c_int) -> Result<Table> {
+    pub fn create_table_with_capacity(&self, narr: usize, nrec: usize) -> Result<Table> {
         let state = self.state();
         unsafe {
             if self.unlikely_memory_error() {
@@ -1430,7 +1449,7 @@ impl Lua {
             let iter = iter.into_iter();
             let lower_bound = iter.size_hint().0;
             let protect = !self.unlikely_memory_error();
-            push_table(state, 0, lower_bound as c_int, protect)?;
+            push_table(state, 0, lower_bound, protect)?;
             for (k, v) in iter {
                 self.push_value(k.into_lua(self)?)?;
                 self.push_value(v.into_lua(self)?)?;
@@ -1459,7 +1478,7 @@ impl Lua {
             let iter = iter.into_iter();
             let lower_bound = iter.size_hint().0;
             let protect = !self.unlikely_memory_error();
-            push_table(state, lower_bound as c_int, 0, protect)?;
+            push_table(state, lower_bound, 0, protect)?;
             for (i, v) in iter.enumerate() {
                 self.push_value(v.into_lua(self)?)?;
                 if protect {
@@ -1524,7 +1543,7 @@ impl Lua {
     where
         A: FromLuaMulti<'lua>,
         R: IntoLuaMulti<'lua>,
-        F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>,
+        F: Fn(&'lua Lua, A) -> Result<R> + MaybeSend + 'static,
     {
         self.create_callback(Box::new(move |lua, args| {
             func(lua, A::from_lua_multi_args(args, 1, None, lua)?)?.into_lua_multi(lua)
@@ -1541,7 +1560,7 @@ impl Lua {
     where
         A: FromLuaMulti<'lua>,
         R: IntoLuaMulti<'lua>,
-        F: 'static + MaybeSend + FnMut(&'lua Lua, A) -> Result<R>,
+        F: FnMut(&'lua Lua, A) -> Result<R> + MaybeSend + 'static,
     {
         let func = RefCell::new(func);
         self.create_function(move |lua, args| {
@@ -1582,11 +1601,10 @@ impl Lua {
     ///
     /// ```
     /// use std::time::Duration;
-    /// use futures_timer::Delay;
     /// use mlua::{Lua, Result};
     ///
     /// async fn sleep(_lua: &Lua, n: u64) -> Result<&'static str> {
-    ///     Delay::new(Duration::from_millis(n)).await;
+    ///     tokio::time::sleep(Duration::from_millis(n)).await;
     ///     Ok("done")
     /// }
     ///
@@ -1608,15 +1626,16 @@ impl Lua {
     where
         A: FromLuaMulti<'lua>,
         R: IntoLuaMulti<'lua>,
-        F: 'static + MaybeSend + Fn(&'lua Lua, A) -> FR,
-        FR: 'lua + Future<Output = Result<R>>,
+        F: Fn(&'lua Lua, A) -> FR + MaybeSend + 'static,
+        FR: Future<Output = Result<R>> + 'lua,
     {
         self.create_async_callback(Box::new(move |lua, args| {
             let args = match A::from_lua_multi_args(args, 1, None, lua) {
                 Ok(args) => args,
                 Err(e) => return Box::pin(future::err(e)),
             };
-            Box::pin(func(lua, args).and_then(move |ret| future::ready(ret.into_lua_multi(lua))))
+            let fut = func(lua, args);
+            Box::pin(async move { fut.await?.into_lua_multi(lua) })
         }))
     }
 
@@ -1624,6 +1643,13 @@ impl Lua {
     ///
     /// Equivalent to `coroutine.create`.
     pub fn create_thread<'lua>(&'lua self, func: Function) -> Result<Thread<'lua>> {
+        self.create_thread_inner(&func)
+    }
+
+    /// Wraps a Lua function into a new thread (or coroutine).
+    ///
+    /// Takes function by reference.
+    fn create_thread_inner<'lua>(&'lua self, func: &Function) -> Result<Thread<'lua>> {
         let state = self.state();
         unsafe {
             let _sg = StackGuard::new(state);
@@ -1672,7 +1698,7 @@ impl Lua {
                 return Ok(Thread(LuaRef::new(self, index)));
             }
         };
-        self.create_thread(func.clone())
+        self.create_thread_inner(func)
     }
 
     /// Resets thread (coroutine) and returns to the pool for later use.
@@ -1750,9 +1776,9 @@ impl Lua {
     /// This methods provides a way to add fields or methods to userdata objects of a type `T`.
     pub fn register_userdata_type<T: 'static>(
         &self,
-        f: impl FnOnce(&mut UserDataRegistrar<T>),
+        f: impl FnOnce(&mut UserDataRegistry<T>),
     ) -> Result<()> {
-        let mut registry = UserDataRegistrar::new();
+        let mut registry = UserDataRegistry::new();
         f(&mut registry);
 
         unsafe {
@@ -1803,7 +1829,7 @@ impl Lua {
     #[inline]
     pub fn create_proxy<T>(&self) -> Result<AnyUserData>
     where
-        T: 'static + UserData,
+        T: UserData + 'static,
     {
         unsafe { self.make_userdata(UserDataCell::new(UserDataProxy::<T>(PhantomData))) }
     }
@@ -2134,8 +2160,7 @@ impl Lua {
             return Ok(());
         } else if t != Value::Nil && key.registry_id == ffi::LUA_REFNIL {
             // We cannot update `LUA_REFNIL` slot
-            let err = "cannot replace nil value with non-nil".to_string();
-            return Err(Error::RuntimeError(err));
+            return Err(Error::runtime("cannot replace nil value with non-nil"));
         }
 
         let state = self.state();
@@ -2270,8 +2295,11 @@ impl Lua {
         extra.app_data.remove()
     }
 
-    // Uses 2 stack spaces, does not call checkstack
-    pub(crate) unsafe fn push_value(&self, value: Value) -> Result<()> {
+    /// Pushes a value onto the Lua stack.
+    ///
+    /// Uses 2 stack spaces, does not call checkstack.
+    #[doc(hidden)]
+    pub unsafe fn push_value(&self, value: Value) -> Result<()> {
         let state = self.state();
         match value {
             Value::Nil => {
@@ -2295,8 +2323,11 @@ impl Lua {
             }
 
             #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) => {
-                ffi::lua_pushvector(state, x, y, z);
+            Value::Vector(v) => {
+                #[cfg(not(feature = "luau-vector4"))]
+                ffi::lua_pushvector(state, v.x(), v.y(), v.z());
+                #[cfg(feature = "luau-vector4")]
+                ffi::lua_pushvector(state, v.x(), v.y(), v.z(), v.w());
             }
 
             Value::String(s) => {
@@ -2328,8 +2359,11 @@ impl Lua {
         Ok(())
     }
 
-    // Uses 2 stack spaces, does not call checkstack
-    pub(crate) unsafe fn pop_value(&self) -> Value {
+    /// Pops a value from the Lua stack.
+    ///
+    /// Uses 2 stack spaces, does not call checkstack.
+    #[doc(hidden)]
+    pub unsafe fn pop_value(&self) -> Value {
         let state = self.state();
         match ffi::lua_type(state, -1) {
             ffi::LUA_TNIL => {
@@ -2379,7 +2413,10 @@ impl Lua {
             ffi::LUA_TVECTOR => {
                 let v = ffi::lua_tovector(state, -1);
                 mlua_debug_assert!(!v.is_null(), "vector is null");
-                let vec = Value::Vector(*v, *v.add(1), *v.add(2));
+                #[cfg(not(feature = "luau-vector4"))]
+                let vec = Value::Vector(Vector([*v, *v.add(1), *v.add(2)]));
+                #[cfg(feature = "luau-vector4")]
+                let vec = Value::Vector(Vector([*v, *v.add(1), *v.add(2), *v.add(3)]));
                 ffi::lua_pop(state, 1);
                 vec
             }
@@ -2490,7 +2527,7 @@ impl Lua {
 
     unsafe fn register_userdata_metatable<'lua, T: 'static>(
         &'lua self,
-        mut registry: UserDataRegistrar<'lua, T>,
+        mut registry: UserDataRegistry<'lua, T>,
     ) -> Result<Integer> {
         let state = self.state();
         let _sg = StackGuard::new(state);
@@ -2500,7 +2537,7 @@ impl Lua {
         let metatable_nrec = registry.meta_methods.len() + registry.meta_fields.len();
         #[cfg(feature = "async")]
         let metatable_nrec = metatable_nrec + registry.async_meta_methods.len();
-        push_table(state, 0, metatable_nrec as c_int, true)?;
+        push_table(state, 0, metatable_nrec, true)?;
         for (k, m) in registry.meta_methods {
             self.push_value(Value::Function(self.create_callback(m)?))?;
             rawset_field(state, -2, MetaMethod::validate(&k)?)?;
@@ -2535,7 +2572,7 @@ impl Lua {
                     if index_type == ffi::LUA_TNIL {
                         // Create a new table
                         ffi::lua_pop(state, 1);
-                        push_table(state, 0, fields_nrec as c_int, true)?;
+                        push_table(state, 0, fields_nrec, true)?;
                     }
                     for (k, f) in registry.fields {
                         self.push_value(f(self, MultiValue::new())?.pop_front().unwrap())?;
@@ -2555,7 +2592,7 @@ impl Lua {
         let mut field_getters_index = None;
         let field_getters_nrec = registry.field_getters.len();
         if field_getters_nrec > 0 {
-            push_table(state, 0, field_getters_nrec as c_int, true)?;
+            push_table(state, 0, field_getters_nrec, true)?;
             for (k, m) in registry.field_getters {
                 self.push_value(Value::Function(self.create_callback(m)?))?;
                 rawset_field(state, -2, &k)?;
@@ -2567,7 +2604,7 @@ impl Lua {
         let mut field_setters_index = None;
         let field_setters_nrec = registry.field_setters.len();
         if field_setters_nrec > 0 {
-            push_table(state, 0, field_setters_nrec as c_int, true)?;
+            push_table(state, 0, field_setters_nrec, true)?;
             for (k, m) in registry.field_setters {
                 self.push_value(Value::Function(self.create_callback(m)?))?;
                 rawset_field(state, -2, &k)?;
@@ -2588,7 +2625,7 @@ impl Lua {
                 _ => {
                     // Create a new table
                     ffi::lua_pop(state, 1);
-                    push_table(state, 0, methods_nrec as c_int, true)?;
+                    push_table(state, 0, methods_nrec, true)?;
                 }
             }
             for (k, m) in registry.methods {
@@ -2614,12 +2651,21 @@ impl Lua {
             }
         }
 
-        init_userdata_metatable::<UserDataCell<T>>(
+        #[cfg(feature = "luau")]
+        let extra_init = None;
+        #[cfg(not(feature = "luau"))]
+        let extra_init: Option<fn(*mut ffi::lua_State) -> Result<()>> = Some(|state| {
+            ffi::lua_pushcfunction(state, util::userdata_destructor::<UserDataCell<T>>);
+            rawset_field(state, -2, "__gc")
+        });
+
+        init_userdata_metatable(
             state,
             metatable_index,
             field_getters_index,
             field_setters_index,
             methods_index,
+            extra_init,
         )?;
 
         // Pop extra tables to get metatable on top of the stack
@@ -2658,18 +2704,17 @@ impl Lua {
         }
     }
 
-    // Pushes a LuaRef value onto the stack, checking that it's a registered
+    // Returns `TypeId` for the LuaRef, checking that it's a registered
     // and not destructed UserData.
-    // Uses 2 stack spaces, does not call checkstack.
-    pub(crate) unsafe fn push_userdata_ref(&self, lref: &LuaRef) -> Result<Option<TypeId>> {
-        let state = self.state();
-        self.push_ref(lref);
-        if ffi::lua_getmetatable(state, -1) == 0 {
-            ffi::lua_pop(state, 1);
+    //
+    // Returns `None` if the userdata is registered but non-static.
+    pub(crate) unsafe fn get_userdata_type_id(&self, lref: &LuaRef) -> Result<Option<TypeId>> {
+        let ref_thread = self.ref_thread();
+        if ffi::lua_getmetatable(ref_thread, lref.index) == 0 {
             return Err(Error::UserDataTypeMismatch);
         }
-        let mt_ptr = ffi::lua_topointer(state, -1);
-        ffi::lua_pop(state, 1);
+        let mt_ptr = ffi::lua_topointer(ref_thread, -1);
+        ffi::lua_pop(ref_thread, 1);
 
         // Fast path to skip looking up the metatable in the map
         let (last_mt, last_type_id) = (*self.extra.get()).last_checked_userdata_mt;
@@ -2689,6 +2734,14 @@ impl Lua {
         }
     }
 
+    // Pushes a LuaRef (userdata) value onto the stack, returning their `TypeId`.
+    // Uses 1 stack space, does not call checkstack.
+    pub(crate) unsafe fn push_userdata_ref(&self, lref: &LuaRef) -> Result<Option<TypeId>> {
+        let type_id = self.get_userdata_type_id(lref)?;
+        self.push_ref(lref);
+        Ok(type_id)
+    }
+
     // Creates a Function out of a Callback containing a 'static Fn. This is safe ONLY because the
     // Fn is 'static, otherwise it could capture 'lua arguments improperly. Without ATCs, we
     // cannot easily deal with the "correct" callback type of:
@@ -2940,7 +2993,7 @@ impl Lua {
             }
 
             // Create new metatable from UserData definition
-            let mut registry = UserDataRegistrar::new();
+            let mut registry = UserDataRegistry::new();
             T::add_fields(&mut registry);
             T::add_methods(&mut registry);
 
@@ -2960,7 +3013,7 @@ impl Lua {
             }
 
             // Create empty metatable
-            let registry = UserDataRegistrar::new();
+            let registry = UserDataRegistry::new();
             self.register_userdata_metatable::<T>(registry)
         })
     }
@@ -3041,7 +3094,13 @@ impl Lua {
         (*self.extra.get())
             .mem_state
             .map(|x| x.as_ref().memory_limit() == 0)
-            .unwrap_or_default()
+            .unwrap_or_else(|| {
+                // Alternatively, check the special flag (only for module mode)
+                #[cfg(feature = "module")]
+                return (*self.extra.get()).skip_memory_check;
+                #[cfg(not(feature = "module"))]
+                return false;
+            })
     }
 
     #[cfg(feature = "unstable")]

src/luau.rs

@@ -70,7 +70,7 @@ unsafe extern "C" fn lua_collectgarbage(state: *mut ffi::lua_State) -> c_int {
 }
 
 fn lua_require(lua: &Lua, name: Option<StdString>) -> Result<Value> {
-    let name = name.ok_or_else(|| Error::RuntimeError("invalid module name".into()))?;
+    let name = name.ok_or_else(|| Error::runtime("invalid module name"))?;
 
     // Find module in the cache
     let state = lua.state();
@@ -101,7 +101,7 @@ fn lua_require(lua: &Lua, name: Option<StdString>) -> Result<Value> {
             break;
         }
     }
-    let source = source.ok_or_else(|| Error::RuntimeError(format!("cannot find '{name}'")))?;
+    let source = source.ok_or_else(|| Error::runtime(format!("cannot find '{name}'")))?;
 
     let value = lua
         .load(&source)
@@ -126,6 +126,12 @@ unsafe extern "C" fn lua_vector(state: *mut ffi::lua_State) -> c_int {
     let x = ffi::luaL_checknumber(state, 1) as c_float;
     let y = ffi::luaL_checknumber(state, 2) as c_float;
     let z = ffi::luaL_checknumber(state, 3) as c_float;
+    #[cfg(feature = "luau-vector4")]
+    let w = ffi::luaL_checknumber(state, 4) as c_float;
+
+    #[cfg(not(feature = "luau-vector4"))]
     ffi::lua_pushvector(state, x, y, z);
+    #[cfg(feature = "luau-vector4")]
+    ffi::lua_pushvector(state, x, y, z, w);
     1
 }

src/prelude.rs

@@ -13,7 +13,7 @@ pub use crate::{
     Thread as LuaThread, ThreadStatus as LuaThreadStatus, UserData as LuaUserData,
     UserDataFields as LuaUserDataFields, UserDataMetatable as LuaUserDataMetatable,
     UserDataMethods as LuaUserDataMethods, UserDataRef as LuaUserDataRef,
-    UserDataRefMut as LuaUserDataRefMut, UserDataRegistrar as LuaUserDataRegistrar,
+    UserDataRefMut as LuaUserDataRefMut, UserDataRegistry as LuaUserDataRegistry,
     Value as LuaValue,
 };
 
@@ -23,7 +23,7 @@ pub use crate::HookTriggers as LuaHookTriggers;
 
 #[cfg(feature = "luau")]
 #[doc(no_inline)]
-pub use crate::{CoverageInfo as LuaCoverageInfo, VmState as LuaVmState};
+pub use crate::{CoverageInfo as LuaCoverageInfo, Vector as LuaVector, VmState as LuaVmState};
 
 #[cfg(feature = "async")]
 #[doc(no_inline)]

src/scope.rs

@@ -2,7 +2,6 @@ use std::any::Any;
 use std::cell::{Cell, RefCell};
 use std::marker::PhantomData;
 use std::mem;
-use std::os::raw::c_int;
 
 #[cfg(feature = "serialize")]
 use serde::Serialize;
@@ -14,10 +13,10 @@ use crate::types::{Callback, CallbackUpvalue, LuaRef, MaybeSend};
 use crate::userdata::{
     AnyUserData, MetaMethod, UserData, UserDataCell, UserDataFields, UserDataMethods,
 };
-use crate::userdata_impl::UserDataRegistrar;
+use crate::userdata_impl::UserDataRegistry;
 use crate::util::{
-    assert_stack, check_stack, get_userdata, init_userdata_metatable, push_table, rawset_field,
-    take_userdata, StackGuard,
+    self, assert_stack, check_stack, get_userdata, init_userdata_metatable, push_table,
+    rawset_field, take_userdata, StackGuard,
 };
 use crate::value::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, MultiValue, Value};
 
@@ -240,7 +239,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             #[cfg(feature = "lua54")]
             for i in 1..=USER_VALUE_MAXSLOT {
                 ffi::lua_pushnil(state);
-                ffi::lua_setiuservalue(state, -2, i as c_int);
+                ffi::lua_setiuservalue(state, -2, i as _);
             }
             #[cfg(any(feature = "lua53", feature = "lua52", feature = "luau"))]
             {
@@ -369,7 +368,6 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             check_stack(state, 13)?;
 
             #[cfg(not(feature = "luau"))]
-            #[allow(clippy::let_and_return)]
             let ud_ptr = protect_lua!(state, 0, 1, |state| {
                 let ud = ffi::lua_newuserdata(state, mem::size_of::<UserDataCell<T>>());
 
@@ -384,13 +382,13 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             })?;
             #[cfg(feature = "luau")]
             let ud_ptr = {
-                crate::util::push_userdata(state, UserDataCell::new(data), true)?;
+                util::push_userdata(state, UserDataCell::new(data), true)?;
                 ffi::lua_touserdata(state, -1) as *const UserDataCell<T>
             };
 
             // Prepare metatable, add meta methods first and then meta fields
             let meta_methods_nrec = ud_methods.meta_methods.len() + ud_fields.meta_fields.len() + 1;
-            push_table(state, 0, meta_methods_nrec as c_int, true)?;
+            push_table(state, 0, meta_methods_nrec, true)?;
 
             for (k, m) in ud_methods.meta_methods {
                 lua.push_value(Value::Function(wrap_method(self, ud_ptr, m)?))?;
@@ -405,7 +403,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             let mut field_getters_index = None;
             let field_getters_nrec = ud_fields.field_getters.len();
             if field_getters_nrec > 0 {
-                push_table(state, 0, field_getters_nrec as c_int, true)?;
+                push_table(state, 0, field_getters_nrec, true)?;
                 for (k, m) in ud_fields.field_getters {
                     lua.push_value(Value::Function(wrap_method(self, ud_ptr, m)?))?;
                     rawset_field(state, -2, &k)?;
@@ -416,7 +414,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             let mut field_setters_index = None;
             let field_setters_nrec = ud_fields.field_setters.len();
             if field_setters_nrec > 0 {
-                push_table(state, 0, field_setters_nrec as c_int, true)?;
+                push_table(state, 0, field_setters_nrec, true)?;
                 for (k, m) in ud_fields.field_setters {
                     lua.push_value(Value::Function(wrap_method(self, ud_ptr, m)?))?;
                     rawset_field(state, -2, &k)?;
@@ -428,7 +426,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
             let methods_nrec = ud_methods.methods.len();
             if methods_nrec > 0 {
                 // Create table used for methods lookup
-                push_table(state, 0, methods_nrec as c_int, true)?;
+                push_table(state, 0, methods_nrec, true)?;
                 for (k, m) in ud_methods.methods {
                     lua.push_value(Value::Function(wrap_method(self, ud_ptr, m)?))?;
                     rawset_field(state, -2, &k)?;
@@ -436,12 +434,21 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
                 methods_index = Some(ffi::lua_absindex(state, -1));
             }
 
-            init_userdata_metatable::<UserDataCell<T>>(
+            #[cfg(feature = "luau")]
+            let extra_init = None;
+            #[cfg(not(feature = "luau"))]
+            let extra_init: Option<fn(*mut ffi::lua_State) -> Result<()>> = Some(|state| {
+                ffi::lua_pushcfunction(state, util::userdata_destructor::<UserDataCell<T>>);
+                rawset_field(state, -2, "__gc")
+            });
+
+            init_userdata_metatable(
                 state,
                 metatable_index,
                 field_getters_index,
                 field_setters_index,
                 methods_index,
+                extra_init,
             )?;
 
             let count = field_getters_index.map(|_| 1).unwrap_or(0)
@@ -479,7 +486,7 @@ impl<'lua, 'scope> Scope<'lua, 'scope> {
                 #[cfg(feature = "lua54")]
                 for i in 1..=USER_VALUE_MAXSLOT {
                     ffi::lua_pushnil(state);
-                    ffi::lua_setiuservalue(state, -2, i as c_int);
+                    ffi::lua_setiuservalue(state, -2, i as _);
                 }
                 #[cfg(any(feature = "lua53", feature = "lua52", feature = "luau"))]
                 {
@@ -611,12 +618,28 @@ impl<'lua, T: UserData> UserDataMethods<'lua, T> for NonStaticUserDataMethods<'l
     }
 
     #[cfg(feature = "async")]
-    fn add_async_method<M, A, MR, R>(&mut self, _name: impl AsRef<str>, _method: M)
+    fn add_async_method<'s, M, A, MR, R>(&mut self, _name: impl AsRef<str>, _method: M)
     where
-        T: Clone,
-        M: Fn(&'lua Lua, T, A) -> MR + MaybeSend + 'static,
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s T, A) -> MR + MaybeSend + 'static,
         A: FromLuaMulti<'lua>,
-        MR: Future<Output = Result<R>> + 'lua,
+        MR: Future<Output = Result<R>> + 's,
+        R: IntoLuaMulti<'lua>,
+    {
+        // The panic should never happen as async non-static code wouldn't compile
+        // Non-static lifetime must be bounded to 'lua lifetime
+        panic!("asynchronous methods are not supported for non-static userdata")
+    }
+
+    #[cfg(feature = "async")]
+    fn add_async_method_mut<'s, M, A, MR, R>(&mut self, _name: impl AsRef<str>, _method: M)
+    where
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s mut T, A) -> MR + MaybeSend + 'static,
+        A: FromLuaMulti<'lua>,
+        MR: Future<Output = Result<R>> + 's,
         R: IntoLuaMulti<'lua>,
     {
         // The panic should never happen as async non-static code wouldn't compile
@@ -686,12 +709,28 @@ impl<'lua, T: UserData> UserDataMethods<'lua, T> for NonStaticUserDataMethods<'l
     }
 
     #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
-    fn add_async_meta_method<M, A, MR, R>(&mut self, _name: impl AsRef<str>, _method: M)
+    fn add_async_meta_method<'s, M, A, MR, R>(&mut self, _name: impl AsRef<str>, _method: M)
     where
-        T: Clone,
-        M: Fn(&'lua Lua, T, A) -> MR + MaybeSend + 'static,
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s T, A) -> MR + MaybeSend + 'static,
         A: FromLuaMulti<'lua>,
-        MR: Future<Output = Result<R>> + 'lua,
+        MR: Future<Output = Result<R>> + 's,
+        R: IntoLuaMulti<'lua>,
+    {
+        // The panic should never happen as async non-static code wouldn't compile
+        // Non-static lifetime must be bounded to 'lua lifetime
+        panic!("asynchronous meta methods are not supported for non-static userdata")
+    }
+
+    #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
+    fn add_async_meta_method_mut<'s, M, A, MR, R>(&mut self, _name: impl AsRef<str>, _method: M)
+    where
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s mut T, A) -> MR + MaybeSend + 'static,
+        A: FromLuaMulti<'lua>,
+        MR: Future<Output = Result<R>> + 's,
         R: IntoLuaMulti<'lua>,
     {
         // The panic should never happen as async non-static code wouldn't compile
@@ -821,7 +860,7 @@ impl<'lua, T: UserData> UserDataFields<'lua, T> for NonStaticUserDataFields<'lua
         self.meta_fields.push((
             name,
             Box::new(move |lua, _| {
-                UserDataRegistrar::<()>::check_meta_field(lua, &name2, value.clone())
+                UserDataRegistry::<()>::check_meta_field(lua, &name2, value.clone())
             }),
         ));
     }
@@ -835,7 +874,7 @@ impl<'lua, T: UserData> UserDataFields<'lua, T> for NonStaticUserDataFields<'lua
         let name2 = name.clone();
         self.meta_fields.push((
             name,
-            Box::new(move |lua, _| UserDataRegistrar::<()>::check_meta_field(lua, &name2, f(lua)?)),
+            Box::new(move |lua, _| UserDataRegistry::<()>::check_meta_field(lua, &name2, f(lua)?)),
         ));
     }
 }

src/serde/de.rs

@@ -124,7 +124,7 @@ impl<'lua, 'de> serde::Deserializer<'de> for Deserializer<'lua> {
             #[allow(clippy::useless_conversion)]
             Value::Number(n) => visitor.visit_f64(n.into()),
             #[cfg(feature = "luau")]
-            Value::Vector(_, _, _) => self.deserialize_seq(visitor),
+            Value::Vector(_) => self.deserialize_seq(visitor),
             Value::String(s) => match s.to_str() {
                 Ok(s) => visitor.visit_str(s),
                 Err(_) => visitor.visit_bytes(s.as_bytes()),
@@ -223,9 +223,9 @@ impl<'lua, 'de> serde::Deserializer<'de> for Deserializer<'lua> {
     {
         match self.value {
             #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) => {
+            Value::Vector(vec) => {
                 let mut deserializer = VecDeserializer {
-                    vec: [x, y, z],
+                    vec,
                     next: 0,
                     options: self.options,
                     visited: self.visited,
@@ -237,7 +237,7 @@ impl<'lua, 'de> serde::Deserializer<'de> for Deserializer<'lua> {
 
                 let len = t.raw_len() as usize;
                 let mut deserializer = SeqDeserializer {
-                    seq: t.raw_sequence_values(),
+                    seq: t.sequence_values(),
                     options: self.options,
                     visited: self.visited,
                 };
@@ -412,7 +412,7 @@ impl<'lua, 'de> de::SeqAccess<'de> for SeqDeserializer<'lua> {
 
 #[cfg(feature = "luau")]
 struct VecDeserializer {
-    vec: [f32; 3],
+    vec: crate::types::Vector,
     next: usize,
     options: Options,
     visited: Rc<RefCell<FxHashSet<*const c_void>>>,
@@ -426,7 +426,7 @@ impl<'de> de::SeqAccess<'de> for VecDeserializer {
     where
         T: de::DeserializeSeed<'de>,
     {
-        match self.vec.get(self.next) {
+        match self.vec.0.get(self.next) {
             Some(&n) => {
                 self.next += 1;
                 let visited = Rc::clone(&self.visited);
@@ -439,7 +439,7 @@ impl<'de> de::SeqAccess<'de> for VecDeserializer {
     }
 
     fn size_hint(&self) -> Option<usize> {
-        Some(3)
+        Some(crate::types::Vector::SIZE)
     }
 }
 

src/serde/ser.rs

@@ -1,5 +1,3 @@
-use std::os::raw::c_int;
-
 use serde::{ser, Serialize};
 
 use super::LuaSerdeExt;
@@ -7,8 +5,6 @@ use crate::error::{Error, Result};
 use crate::lua::Lua;
 use crate::string::String;
 use crate::table::Table;
-use crate::types::Integer;
-use crate::util::{check_stack, StackGuard};
 use crate::value::{IntoLua, Value};
 
 /// A struct for serializing Rust values into Lua values.
@@ -120,9 +116,9 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
 
     // Associated types for keeping track of additional state while serializing
     // compound data structures like sequences and maps.
-    type SerializeSeq = SerializeVec<'lua>;
-    type SerializeTuple = SerializeVec<'lua>;
-    type SerializeTupleStruct = SerializeVec<'lua>;
+    type SerializeSeq = SerializeSeq<'lua>;
+    type SerializeTuple = SerializeSeq<'lua>;
+    type SerializeTupleStruct = SerializeSeq<'lua>;
     type SerializeTupleVariant = SerializeTupleVariant<'lua>;
     type SerializeMap = SerializeMap<'lua>;
     type SerializeStruct = SerializeMap<'lua>;
@@ -235,13 +231,11 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
 
     #[inline]
     fn serialize_seq(self, len: Option<usize>) -> Result<Self::SerializeSeq> {
-        let len = len.unwrap_or(0) as c_int;
-        let table = self.lua.create_table_with_capacity(len, 0)?;
+        let table = self.lua.create_table_with_capacity(len.unwrap_or(0), 0)?;
         if self.options.set_array_metatable {
             table.set_metatable(Some(self.lua.array_metatable()));
         }
-        let options = self.options;
-        Ok(SerializeVec { table, options })
+        Ok(SerializeSeq::new(table, self.options))
     }
 
     #[inline]
@@ -252,9 +246,14 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
     #[inline]
     fn serialize_tuple_struct(
         self,
-        _name: &'static str,
+        name: &'static str,
         len: usize,
     ) -> Result<Self::SerializeTupleStruct> {
+        #[cfg(feature = "luau")]
+        if name == "Vector" && len == crate::types::Vector::SIZE {
+            return Ok(SerializeSeq::new_vector(self.lua, self.options));
+        }
+        _ = name;
         self.serialize_seq(Some(len))
     }
 
@@ -275,10 +274,9 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
 
     #[inline]
     fn serialize_map(self, len: Option<usize>) -> Result<Self::SerializeMap> {
-        let len = len.unwrap_or(0) as c_int;
         Ok(SerializeMap {
             key: None,
-            table: self.lua.create_table_with_capacity(0, len)?,
+            table: self.lua.create_table_with_capacity(0, len.unwrap_or(0))?,
             options: self.options,
         })
     }
@@ -298,19 +296,47 @@ impl<'lua> ser::Serializer for Serializer<'lua> {
     ) -> Result<Self::SerializeStructVariant> {
         Ok(SerializeStructVariant {
             name: self.lua.create_string(variant)?,
-            table: self.lua.create_table_with_capacity(0, len as c_int)?,
+            table: self.lua.create_table_with_capacity(0, len)?,
             options: self.options,
         })
     }
 }
 
 #[doc(hidden)]
-pub struct SerializeVec<'lua> {
-    table: Table<'lua>,
+pub struct SerializeSeq<'lua> {
+    lua: &'lua Lua,
+    #[cfg(feature = "luau")]
+    vector: Option<crate::types::Vector>,
+    table: Option<Table<'lua>>,
+    next: usize,
     options: Options,
 }
 
-impl<'lua> ser::SerializeSeq for SerializeVec<'lua> {
+impl<'lua> SerializeSeq<'lua> {
+    const fn new(table: Table<'lua>, options: Options) -> Self {
+        Self {
+            lua: table.0.lua,
+            #[cfg(feature = "luau")]
+            vector: None,
+            table: Some(table),
+            next: 0,
+            options,
+        }
+    }
+
+    #[cfg(feature = "luau")]
+    const fn new_vector(lua: &'lua Lua, options: Options) -> Self {
+        Self {
+            lua,
+            vector: Some(crate::types::Vector::zero()),
+            table: None,
+            next: 0,
+            options,
+        }
+    }
+}
+
+impl<'lua> ser::SerializeSeq for SerializeSeq<'lua> {
     type Ok = Value<'lua>;
     type Error = Error;
 
@@ -318,35 +344,19 @@ impl<'lua> ser::SerializeSeq for SerializeVec<'lua> {
     where
         T: Serialize + ?Sized,
     {
-        let lua = self.table.0.lua;
-        let state = lua.state();
-        let value = lua.to_value_with(value, self.options)?;
-        unsafe {
-            let _sg = StackGuard::new(state);
-            check_stack(state, 4)?;
-
-            lua.push_ref(&self.table.0);
-            lua.push_value(value)?;
-            if lua.unlikely_memory_error() {
-                let len = ffi::lua_rawlen(state, -2) as Integer;
-                ffi::lua_rawseti(state, -2, len + 1);
-                ffi::lua_pop(state, 1);
-                Ok(())
-            } else {
-                protect_lua!(state, 2, 0, fn(state) {
-                    let len = ffi::lua_rawlen(state, -2) as Integer;
-                    ffi::lua_rawseti(state, -2, len + 1);
-                })
-            }
-        }
+        let value = self.lua.to_value_with(value, self.options)?;
+        let table = self.table.as_ref().unwrap();
+        table.raw_seti(self.next + 1, value)?;
+        self.next += 1;
+        Ok(())
     }
 
     fn end(self) -> Result<Value<'lua>> {
-        Ok(Value::Table(self.table))
+        Ok(Value::Table(self.table.unwrap()))
     }
 }
 
-impl<'lua> ser::SerializeTuple for SerializeVec<'lua> {
+impl<'lua> ser::SerializeTuple for SerializeSeq<'lua> {
     type Ok = Value<'lua>;
     type Error = Error;
 
@@ -362,7 +372,7 @@ impl<'lua> ser::SerializeTuple for SerializeVec<'lua> {
     }
 }
 
-impl<'lua> ser::SerializeTupleStruct for SerializeVec<'lua> {
+impl<'lua> ser::SerializeTupleStruct for SerializeSeq<'lua> {
     type Ok = Value<'lua>;
     type Error = Error;
 
@@ -370,10 +380,22 @@ impl<'lua> ser::SerializeTupleStruct for SerializeVec<'lua> {
     where
         T: Serialize + ?Sized,
     {
+        #[cfg(feature = "luau")]
+        if let Some(vector) = self.vector.as_mut() {
+            let value = self.lua.to_value_with(value, self.options)?;
+            let value = self.lua.unpack(value)?;
+            vector.0[self.next] = value;
+            self.next += 1;
+            return Ok(());
+        }
         ser::SerializeSeq::serialize_element(self, value)
     }
 
     fn end(self) -> Result<Value<'lua>> {
+        #[cfg(feature = "luau")]
+        if let Some(vector) = self.vector {
+            return Ok(Value::Vector(vector));
+        }
         ser::SerializeSeq::end(self)
     }
 }
@@ -394,9 +416,7 @@ impl<'lua> ser::SerializeTupleVariant for SerializeTupleVariant<'lua> {
         T: Serialize + ?Sized,
     {
         let lua = self.table.0.lua;
-        let idx = self.table.raw_len() + 1;
-        self.table
-            .raw_insert(idx, lua.to_value_with(value, self.options)?)
+        self.table.raw_push(lua.to_value_with(value, self.options)?)
     }
 
     fn end(self) -> Result<Value<'lua>> {

src/string.rs

@@ -139,8 +139,7 @@ impl<'lua> String<'lua> {
     /// Typically this function is used only for hashing and debug information.
     #[inline]
     pub fn to_pointer(&self) -> *const c_void {
-        let ref_thread = self.0.lua.ref_thread();
-        unsafe { ffi::lua_topointer(ref_thread, self.0.index) }
+        self.0.to_pointer()
     }
 
     /// Convert this handle to owned version.

src/table.rs

@@ -45,7 +45,6 @@ impl OwnedTable {
     }
 }
 
-#[allow(clippy::len_without_is_empty)]
 impl<'lua> Table<'lua> {
     /// Sets a key-value pair in the table.
     ///
@@ -150,11 +149,15 @@ impl<'lua> Table<'lua> {
     }
 
     /// Checks whether the table contains a non-nil value for `key`.
+    ///
+    /// This might invoke the `__index` metamethod.
     pub fn contains_key<K: IntoLua<'lua>>(&self, key: K) -> Result<bool> {
         Ok(self.get::<_, Value>(key)? != Value::Nil)
     }
 
     /// Appends a value to the back of the table.
+    ///
+    /// This might invoke the `__len` and `__newindex` metamethods.
     pub fn push<V: IntoLua<'lua>>(&self, value: V) -> Result<()> {
         // Fast track
         if !self.has_metatable() {
@@ -179,6 +182,8 @@ impl<'lua> Table<'lua> {
     }
 
     /// Removes the last element from the table and returns it.
+    ///
+    /// This might invoke the `__len` and `__newindex` metamethods.
     pub fn pop<V: FromLua<'lua>>(&self) -> Result<V> {
         // Fast track
         if !self.has_metatable() {
@@ -314,7 +319,7 @@ impl<'lua> Table<'lua> {
 
         let size = self.raw_len();
         if idx < 1 || idx > size + 1 {
-            return Err(Error::RuntimeError("index out of bounds".to_string()));
+            return Err(Error::runtime("index out of bounds"));
         }
 
         let value = value.into_lua(lua)?;
@@ -402,7 +407,7 @@ impl<'lua> Table<'lua> {
             Value::Integer(idx) => {
                 let size = self.raw_len();
                 if idx < 1 || idx > size {
-                    return Err(Error::RuntimeError("index out of bounds".to_string()));
+                    return Err(Error::runtime("index out of bounds"));
                 }
                 unsafe {
                     let _sg = StackGuard::new(state);
@@ -492,6 +497,32 @@ impl<'lua> Table<'lua> {
         unsafe { ffi::lua_rawlen(ref_thread, self.0.index) as Integer }
     }
 
+    /// Returns `true` if the table is empty, without invoking metamethods.
+    ///
+    /// It checks both the array part and the hash part.
+    pub fn is_empty(&self) -> bool {
+        // Check array part
+        if self.raw_len() != 0 {
+            return false;
+        }
+
+        // Check hash part
+        let lua = self.0.lua;
+        let state = lua.state();
+        unsafe {
+            let _sg = StackGuard::new(state);
+            assert_stack(state, 4);
+
+            lua.push_ref(&self.0);
+            ffi::lua_pushnil(state);
+            if ffi::lua_next(state, -2) != 0 {
+                return false;
+            }
+        }
+
+        true
+    }
+
     /// Returns a reference to the metatable of this table, or `None` if no metatable is set.
     ///
     /// Unlike the `getmetatable` Lua function, this method ignores the `__metatable` field.
@@ -586,8 +617,7 @@ impl<'lua> Table<'lua> {
     /// Typically this function is used only for hashing and debug information.
     #[inline]
     pub fn to_pointer(&self) -> *const c_void {
-        let ref_thread = self.0.lua.ref_thread();
-        unsafe { ffi::lua_topointer(ref_thread, self.0.index) }
+        self.0.to_pointer()
     }
 
     /// Convert this handle to owned version.
@@ -641,12 +671,9 @@ impl<'lua> Table<'lua> {
 
     /// Consume this table and return an iterator over all values in the sequence part of the table.
     ///
-    /// The iterator will yield all values `t[1]`, `t[2]`, and so on, until a `nil` value is
-    /// encountered. This mirrors the behavior of Lua's `ipairs` function and will invoke the
-    /// `__index` metamethod according to the usual rules. However, the deprecated `__ipairs`
-    /// metatable will not be called.
-    ///
-    /// Just like [`pairs`], the values are wrapped in a [`Result`].
+    /// The iterator will yield all values `t[1]`, `t[2]` and so on, until a `nil` value is
+    /// encountered. This mirrors the behavior of Lua's `ipairs` function but does not invoke
+    /// any metamethods.
     ///
     /// # Note
     ///
@@ -685,28 +712,18 @@ impl<'lua> Table<'lua> {
             table: self.0,
             index: Some(1),
             len: None,
-            raw: false,
             _phantom: PhantomData,
         }
     }
 
-    /// Consume this table and return an iterator over all values in the sequence part of the table.
-    ///
-    /// Unlike the `sequence_values`, does not invoke `__index` metamethod when iterating.
-    ///
-    /// [`sequence_values`]: #method.sequence_values
+    #[doc(hidden)]
+    #[deprecated(since = "0.9.0", note = "use `sequence_values` instead")]
     pub fn raw_sequence_values<V: FromLua<'lua>>(self) -> TableSequence<'lua, V> {
-        TableSequence {
-            table: self.0,
-            index: Some(1),
-            len: None,
-            raw: true,
-            _phantom: PhantomData,
-        }
+        self.sequence_values()
     }
 
     #[cfg(feature = "serialize")]
-    pub(crate) fn raw_sequence_values_by_len<V: FromLua<'lua>>(
+    pub(crate) fn sequence_values_by_len<V: FromLua<'lua>>(
         self,
         len: Option<Integer>,
     ) -> TableSequence<'lua, V> {
@@ -715,11 +732,37 @@ impl<'lua> Table<'lua> {
             table: self.0,
             index: Some(1),
             len: Some(len),
-            raw: true,
             _phantom: PhantomData,
         }
     }
 
+    /// Sets element value at position `idx` without invoking metamethods.
+    #[allow(dead_code)]
+    pub(crate) fn raw_seti<V: IntoLua<'lua>>(&self, idx: usize, value: V) -> Result<()> {
+        #[cfg(feature = "luau")]
+        self.check_readonly_write()?;
+
+        let lua = self.0.lua;
+        let state = lua.state();
+        let value = value.into_lua(lua)?;
+
+        unsafe {
+            let _sg = StackGuard::new(state);
+            check_stack(state, 5)?;
+
+            lua.push_ref(&self.0);
+            lua.push_value(value)?;
+
+            let idx = idx.try_into().unwrap();
+            if lua.unlikely_memory_error() {
+                ffi::lua_rawseti(state, -2, idx);
+            } else {
+                protect_lua!(state, 2, 0, |state| ffi::lua_rawseti(state, -2, idx))?;
+            }
+            Ok(())
+        }
+    }
+
     #[cfg(feature = "serialize")]
     pub(crate) fn is_array(&self) -> bool {
         let lua = self.0.lua;
@@ -741,8 +784,7 @@ impl<'lua> Table<'lua> {
     #[inline(always)]
     pub(crate) fn check_readonly_write(&self) -> Result<()> {
         if self.is_readonly() {
-            let err = "attempt to modify a readonly table".to_string();
-            return Err(Error::RuntimeError(err));
+            return Err(Error::runtime("attempt to modify a readonly table"));
         }
         Ok(())
     }
@@ -797,6 +839,56 @@ impl<'lua> AsRef<Table<'lua>> for Table<'lua> {
     }
 }
 
+impl<'lua, T> PartialEq<[T]> for Table<'lua>
+where
+    T: IntoLua<'lua> + Clone,
+{
+    fn eq(&self, other: &[T]) -> bool {
+        let lua = self.0.lua;
+        let state = lua.state();
+        unsafe {
+            let _sg = StackGuard::new(state);
+            assert_stack(state, 4);
+
+            lua.push_ref(&self.0);
+
+            let len = ffi::lua_rawlen(state, -1);
+            for i in 0..len {
+                ffi::lua_rawgeti(state, -1, (i + 1) as _);
+                let val = lua.pop_value();
+                if val == Nil {
+                    return i == other.len();
+                }
+                match other.get(i).map(|v| v.clone().into_lua(lua)) {
+                    Some(Ok(other_val)) if val == other_val => continue,
+                    _ => return false,
+                }
+            }
+        }
+        true
+    }
+}
+
+impl<'lua, T> PartialEq<&[T]> for Table<'lua>
+where
+    T: IntoLua<'lua> + Clone,
+{
+    #[inline]
+    fn eq(&self, other: &&[T]) -> bool {
+        self == *other
+    }
+}
+
+impl<'lua, T, const N: usize> PartialEq<[T; N]> for Table<'lua>
+where
+    T: IntoLua<'lua> + Clone,
+{
+    #[inline]
+    fn eq(&self, other: &[T; N]) -> bool {
+        self == &other[..]
+    }
+}
+
 /// An extension trait for `Table`s that provides a variety of convenient functionality.
 pub trait TableExt<'lua>: Sealed {
     /// Calls the table as function assuming it has `__call` metamethod.
@@ -812,11 +904,10 @@ pub trait TableExt<'lua>: Sealed {
     /// The metamethod is called with the table as its first argument, followed by the passed arguments.
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn call_async<'fut, A, R>(&self, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async<A, R>(&self, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut;
+        R: FromLuaMulti<'lua> + 'lua;
 
     /// Gets the function associated to `key` from the table and executes it,
     /// passing the table itself along with `args` as function arguments.
@@ -825,9 +916,8 @@ pub trait TableExt<'lua>: Sealed {
     /// `table.get::<_, Function>(key)?.call((table.clone(), arg1, ..., argN))`
     ///
     /// This might invoke the `__index` metamethod.
-    fn call_method<K, A, R>(&self, key: K, args: A) -> Result<R>
+    fn call_method<A, R>(&self, name: &str, args: A) -> Result<R>
     where
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>;
 
@@ -838,9 +928,8 @@ pub trait TableExt<'lua>: Sealed {
     /// `table.get::<_, Function>(key)?.call(args)`
     ///
     /// This might invoke the `__index` metamethod.
-    fn call_function<K, A, R>(&self, key: K, args: A) -> Result<R>
+    fn call_function<A, R>(&self, name: &str, args: A) -> Result<R>
     where
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>;
 
@@ -852,12 +941,10 @@ pub trait TableExt<'lua>: Sealed {
     /// This might invoke the `__index` metamethod.
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn call_async_method<'fut, K, A, R>(&self, key: K, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_method<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut;
+        R: FromLuaMulti<'lua> + 'lua;
 
     /// Gets the function associated to `key` from the table and asynchronously executes it,
     /// passing `args` as function arguments and returning Future.
@@ -867,16 +954,10 @@ pub trait TableExt<'lua>: Sealed {
     /// This might invoke the `__index` metamethod.
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn call_async_function<'fut, K, A, R>(
-        &self,
-        key: K,
-        args: A,
-    ) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_function<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut;
+        R: FromLuaMulti<'lua> + 'lua;
 }
 
 impl<'lua> TableExt<'lua> for Table<'lua> {
@@ -890,43 +971,43 @@ impl<'lua> TableExt<'lua> for Table<'lua> {
     }
 
     #[cfg(feature = "async")]
-    fn call_async<'fut, A, R>(&self, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async<A, R>(&self, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
-        Function(self.0.clone()).call_async(args)
+        let args = match args.into_lua_multi(self.0.lua) {
+            Ok(args) => args,
+            Err(e) => return Box::pin(future::err(e)),
+        };
+        let func = Function(self.0.clone());
+        Box::pin(async move { func.call_async(args).await })
     }
 
-    fn call_method<K, A, R>(&self, key: K, args: A) -> Result<R>
+    fn call_method<A, R>(&self, name: &str, args: A) -> Result<R>
     where
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>,
     {
         let lua = self.0.lua;
         let mut args = args.into_lua_multi(lua)?;
         args.push_front(Value::Table(self.clone()));
-        self.get::<_, Function>(key)?.call(args)
+        self.get::<_, Function>(name)?.call(args)
     }
 
-    fn call_function<K, A, R>(&self, key: K, args: A) -> Result<R>
+    fn call_function<A, R>(&self, name: &str, args: A) -> Result<R>
     where
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>,
     {
-        self.get::<_, Function>(key)?.call(args)
+        self.get::<_, Function>(name)?.call(args)
     }
 
     #[cfg(feature = "async")]
-    fn call_async_method<'fut, K, A, R>(&self, key: K, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_method<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
         let lua = self.0.lua;
         let mut args = match args.into_lua_multi(lua) {
@@ -934,19 +1015,22 @@ impl<'lua> TableExt<'lua> for Table<'lua> {
             Err(e) => return Box::pin(future::err(e)),
         };
         args.push_front(Value::Table(self.clone()));
-        self.call_async_function(key, args)
+        self.call_async_function(name, args)
     }
 
     #[cfg(feature = "async")]
-    fn call_async_function<'fut, K, A, R>(&self, key: K, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_function<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
-        K: IntoLua<'lua>,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
-        match self.get::<_, Function>(key) {
-            Ok(func) => func.call_async(args),
+        let lua = self.0.lua;
+        let args = match args.into_lua_multi(lua) {
+            Ok(args) => args,
+            Err(e) => return Box::pin(future::err(e)),
+        };
+        match self.get::<_, Function>(name) {
+            Ok(func) => Box::pin(async move { func.call_async(args).await }),
             Err(e) => Box::pin(future::err(e)),
         }
     }
@@ -975,7 +1059,7 @@ impl<'lua> Serialize for Table<'lua> {
             let len = self.raw_len() as usize;
             if len > 0 || self.is_array() {
                 let mut seq = serializer.serialize_seq(Some(len))?;
-                for v in self.clone().raw_sequence_values_by_len::<Value>(None) {
+                for v in self.clone().sequence_values_by_len::<Value>(None) {
                     let v = v.map_err(serde::ser::Error::custom)?;
                     seq.serialize_element(&v)?;
                 }
@@ -1065,7 +1149,6 @@ pub struct TableSequence<'lua, V> {
     table: LuaRef<'lua>,
     index: Option<Integer>,
     len: Option<Integer>,
-    raw: bool,
     _phantom: PhantomData<V>,
 }
 
@@ -1082,15 +1165,10 @@ where
 
             let res = (|| unsafe {
                 let _sg = StackGuard::new(state);
-                check_stack(state, 1 + if self.raw { 0 } else { 3 })?;
+                check_stack(state, 1)?;
 
                 lua.push_ref(&self.table);
-                let res = if self.raw {
-                    ffi::lua_rawgeti(state, -1, index)
-                } else {
-                    protect_lua!(state, 1, 1, |state| ffi::lua_geti(state, -1, index))?
-                };
-                match res {
+                match ffi::lua_rawgeti(state, -1, index) {
                     ffi::LUA_TNIL if index > self.len.unwrap_or(0) => Ok(None),
                     _ => Ok(Some((index, lua.pop_value()))),
                 }

src/thread.rs

@@ -8,13 +8,6 @@ use crate::types::LuaRef;
 use crate::util::{check_stack, error_traceback_thread, pop_error, StackGuard};
 use crate::value::{FromLuaMulti, IntoLuaMulti};
 
-#[cfg(any(
-    feature = "lua54",
-    all(feature = "luajit", feature = "vendored"),
-    feature = "luau",
-))]
-use crate::function::Function;
-
 #[cfg(not(feature = "luau"))]
 use crate::{
     hook::{Debug, HookTriggers},
@@ -60,14 +53,14 @@ pub struct Thread<'lua>(pub(crate) LuaRef<'lua>);
 ///
 /// Requires `feature = "async"`
 ///
-/// [`Future`]: futures_core::future::Future
-/// [`Stream`]: futures_core::stream::Stream
+/// [`Future`]: std::future::Future
+/// [`Stream`]: futures_util::stream::Stream
 #[cfg(feature = "async")]
 #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct AsyncThread<'lua, R> {
     thread: Thread<'lua>,
-    args0: Option<Result<MultiValue<'lua>>>,
+    init_args: Option<Result<MultiValue<'lua>>>,
     ret: PhantomData<R>,
     recycle: bool,
 }
@@ -223,7 +216,7 @@ impl<'lua> Thread<'lua> {
         all(feature = "luajit", feature = "vendored"),
         feature = "luau",
     ))]
-    pub fn reset(&self, func: Function<'lua>) -> Result<()> {
+    pub fn reset(&self, func: crate::function::Function<'lua>) -> Result<()> {
         let lua = self.0.lua;
         let state = lua.state();
         unsafe {
@@ -272,8 +265,8 @@ impl<'lua> Thread<'lua> {
     ///
     /// Requires `feature = "async"`
     ///
-    /// [`Future`]: futures_core::future::Future
-    /// [`Stream`]: futures_core::stream::Stream
+    /// [`Future`]: std::future::Future
+    /// [`Stream`]: futures_util::stream::Stream
     /// [`resume()`]: https://www.lua.org/manual/5.4/manual.html#lua_resume
     ///
     /// # Examples
@@ -315,7 +308,7 @@ impl<'lua> Thread<'lua> {
         let args = args.into_lua_multi(self.0.lua);
         AsyncThread {
             thread: self,
-            args0: Some(args),
+            init_args: Some(args),
             ret: PhantomData,
             recycle: false,
         }
@@ -427,7 +420,7 @@ where
 
         // This is safe as we are not moving the whole struct
         let this = unsafe { self.get_unchecked_mut() };
-        let ret: MultiValue = if let Some(args) = this.args0.take() {
+        let ret: MultiValue = if let Some(args) = this.init_args.take() {
             this.thread.resume(args?)?
         } else {
             this.thread.resume(())?
@@ -461,7 +454,7 @@ where
 
         // This is safe as we are not moving the whole struct
         let this = unsafe { self.get_unchecked_mut() };
-        let ret: MultiValue = if let Some(args) = this.args0.take() {
+        let ret: MultiValue = if let Some(args) = this.init_args.take() {
             this.thread.resume(args?)?
         } else {
             this.thread.resume(())?

src/types.rs

@@ -8,9 +8,6 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 use std::{fmt, mem, ptr};
 
-#[cfg(feature = "lua54")]
-use std::ffi::CStr;
-
 use rustc_hash::FxHashMap;
 
 #[cfg(feature = "async")]
@@ -20,12 +17,14 @@ use crate::error::Result;
 #[cfg(not(feature = "luau"))]
 use crate::hook::Debug;
 use crate::lua::{ExtraData, Lua};
-use crate::util::{assert_stack, StackGuard};
 use crate::value::MultiValue;
 
 #[cfg(feature = "unstable")]
 use {crate::lua::LuaInner, std::marker::PhantomData};
 
+#[cfg(all(feature = "luau", feature = "serialize"))]
+use serde::ser::{Serialize, SerializeTupleStruct, Serializer};
+
 /// Type of Lua integer numbers.
 pub type Integer = ffi::lua_Integer;
 /// Type of Lua floating point numbers.
@@ -76,10 +75,10 @@ pub(crate) type InterruptCallback = Arc<dyn Fn(&Lua) -> Result<VmState> + Send>;
 pub(crate) type InterruptCallback = Arc<dyn Fn(&Lua) -> Result<VmState>>;
 
 #[cfg(all(feature = "send", feature = "lua54"))]
-pub(crate) type WarnCallback = Box<dyn Fn(&Lua, &CStr, bool) -> Result<()> + Send>;
+pub(crate) type WarnCallback = Box<dyn Fn(&Lua, &str, bool) -> Result<()> + Send>;
 
 #[cfg(all(not(feature = "send"), feature = "lua54"))]
-pub(crate) type WarnCallback = Box<dyn Fn(&Lua, &CStr, bool) -> Result<()>>;
+pub(crate) type WarnCallback = Box<dyn Fn(&Lua, &str, bool) -> Result<()>>;
 
 #[cfg(feature = "send")]
 pub trait MaybeSend: Send {}
@@ -91,6 +90,92 @@ pub trait MaybeSend {}
 #[cfg(not(feature = "send"))]
 impl<T> MaybeSend for T {}
 
+/// A Luau vector type.
+///
+/// By default vectors are 3-dimensional, but can be 4-dimensional
+/// if the `luau-vector4` feature is enabled.
+#[cfg(any(feature = "luau", doc))]
+#[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
+#[derive(Debug, Default, Clone, Copy, PartialEq)]
+pub struct Vector(pub(crate) [f32; Self::SIZE]);
+
+#[cfg(any(feature = "luau", doc))]
+impl fmt::Display for Vector {
+    #[rustfmt::skip]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        #[cfg(not(feature = "luau-vector4"))]
+        return write!(f, "vector({}, {}, {})", self.x(), self.y(), self.z());
+        #[cfg(feature = "luau-vector4")]
+        return write!(f, "vector({}, {}, {}, {})", self.x(), self.y(), self.z(), self.w());
+    }
+}
+
+#[cfg(any(feature = "luau", doc))]
+impl Vector {
+    pub(crate) const SIZE: usize = if cfg!(feature = "luau-vector4") { 4 } else { 3 };
+
+    /// Creates a new vector.
+    #[cfg(not(feature = "luau-vector4"))]
+    pub const fn new(x: f32, y: f32, z: f32) -> Self {
+        Self([x, y, z])
+    }
+
+    /// Creates a new vector.
+    #[cfg(feature = "luau-vector4")]
+    pub const fn new(x: f32, y: f32, z: f32, w: f32) -> Self {
+        Self([x, y, z, w])
+    }
+
+    /// Creates a new vector with all components set to `0.0`.
+    #[doc(hidden)]
+    pub const fn zero() -> Self {
+        Self([0.0; Self::SIZE])
+    }
+
+    /// Returns 1st component of the vector.
+    pub const fn x(&self) -> f32 {
+        self.0[0]
+    }
+
+    /// Returns 2nd component of the vector.
+    pub const fn y(&self) -> f32 {
+        self.0[1]
+    }
+
+    /// Returns 3rd component of the vector.
+    pub const fn z(&self) -> f32 {
+        self.0[2]
+    }
+
+    /// Returns 4th component of the vector.
+    #[cfg(any(feature = "luau-vector4", doc))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "luau-vector4")))]
+    pub const fn w(&self) -> f32 {
+        self.0[3]
+    }
+}
+
+#[cfg(all(feature = "luau", feature = "serialize"))]
+impl Serialize for Vector {
+    fn serialize<S: Serializer>(&self, serializer: S) -> StdResult<S::Ok, S::Error> {
+        let mut ts = serializer.serialize_tuple_struct("Vector", Self::SIZE)?;
+        ts.serialize_field(&self.x())?;
+        ts.serialize_field(&self.y())?;
+        ts.serialize_field(&self.z())?;
+        #[cfg(feature = "luau-vector4")]
+        ts.serialize_field(&self.w())?;
+        ts.end()
+    }
+}
+
+#[cfg(any(feature = "luau", doc))]
+impl PartialEq<[f32; Self::SIZE]> for Vector {
+    #[inline]
+    fn eq(&self, other: &[f32; Self::SIZE]) -> bool {
+        self.0 == *other
+    }
+}
+
 pub(crate) struct DestructedUserdata;
 
 /// An auto generated key into the Lua registry.
@@ -102,14 +187,14 @@ pub(crate) struct DestructedUserdata;
 /// Be warned, If you place this into Lua via a [`UserData`] type or a rust callback, it is *very
 /// easy* to accidentally cause reference cycles that the Lua garbage collector cannot resolve.
 /// Instead of placing a [`RegistryKey`] into a [`UserData`] type, prefer instead to use
-/// [`AnyUserData::set_user_value`] / [`AnyUserData::get_user_value`].
+/// [`AnyUserData::set_user_value`] / [`AnyUserData::user_value`].
 ///
 /// [`UserData`]: crate::UserData
 /// [`RegistryKey`]: crate::RegistryKey
 /// [`Lua::remove_registry_value`]: crate::Lua::remove_registry_value
 /// [`Lua::expire_registry_values`]: crate::Lua::expire_registry_values
 /// [`AnyUserData::set_user_value`]: crate::AnyUserData::set_user_value
-/// [`AnyUserData::get_user_value`]: crate::AnyUserData::get_user_value
+/// [`AnyUserData::user_value`]: crate::AnyUserData::user_value
 pub struct RegistryKey {
     pub(crate) registry_id: c_int,
     pub(crate) is_nil: AtomicBool,
@@ -199,6 +284,11 @@ impl<'lua> LuaRef<'lua> {
         }
     }
 
+    #[inline]
+    pub(crate) fn to_pointer(&self) -> *const c_void {
+        unsafe { ffi::lua_topointer(self.lua.ref_thread(), self.index) }
+    }
+
     #[cfg(feature = "unstable")]
     #[inline]
     pub(crate) fn into_owned(self) -> LuaOwnedRef {
@@ -211,7 +301,7 @@ impl<'lua> LuaRef<'lua> {
 
 impl<'lua> fmt::Debug for LuaRef<'lua> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Ref({})", self.index)
+        write!(f, "Ref({:p})", self.to_pointer())
     }
 }
 
@@ -231,15 +321,12 @@ impl<'lua> Drop for LuaRef<'lua> {
 
 impl<'lua> PartialEq for LuaRef<'lua> {
     fn eq(&self, other: &Self) -> bool {
-        let lua = self.lua;
-        let state = lua.state();
-        unsafe {
-            let _sg = StackGuard::new(state);
-            assert_stack(state, 2);
-            lua.push_ref(self);
-            lua.push_ref(other);
-            ffi::lua_rawequal(state, -1, -2) == 1
-        }
+        let ref_thread = self.lua.ref_thread();
+        assert!(
+            ref_thread == other.lua.ref_thread(),
+            "Lua instance passed Value created from a different main Lua state"
+        );
+        unsafe { ffi::lua_rawequal(ref_thread, self.index, other.index) == 1 }
     }
 }
 
@@ -253,7 +340,7 @@ pub(crate) struct LuaOwnedRef {
 #[cfg(feature = "unstable")]
 impl fmt::Debug for LuaOwnedRef {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "OwnedRef({})", self.index)
+        write!(f, "OwnedRef({:p})", self.to_ref().to_pointer())
     }
 }
 

src/userdata.rs

@@ -24,7 +24,7 @@ use crate::table::{Table, TablePairs};
 use crate::types::{LuaRef, MaybeSend};
 use crate::util::{check_stack, get_userdata, take_userdata, StackGuard};
 use crate::value::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, Value};
-use crate::UserDataRegistrar;
+use crate::UserDataRegistry;
 
 #[cfg(feature = "lua54")]
 pub(crate) const USER_VALUE_MAXSLOT: usize = 8;
@@ -259,8 +259,7 @@ pub trait UserDataMethods<'lua, T> {
         A: FromLuaMulti<'lua>,
         R: IntoLuaMulti<'lua>;
 
-    /// Add an async method which accepts a `T` as the first parameter and returns Future.
-    /// The passed `T` is cloned from the original value.
+    /// Add an async method which accepts a `&T` as the first parameter and returns Future.
     ///
     /// Refer to [`add_method`] for more information about the implementation.
     ///
@@ -269,12 +268,31 @@ pub trait UserDataMethods<'lua, T> {
     /// [`add_method`]: #method.add_method
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn add_async_method<M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    fn add_async_method<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
     where
-        T: Clone,
-        M: Fn(&'lua Lua, T, A) -> MR + MaybeSend + 'static,
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s T, A) -> MR + MaybeSend + 'static,
         A: FromLuaMulti<'lua>,
-        MR: Future<Output = Result<R>> + 'lua,
+        MR: Future<Output = Result<R>> + 's,
+        R: IntoLuaMulti<'lua>;
+
+    /// Add an async method which accepts a `&mut T` as the first parameter and returns Future.
+    ///
+    /// Refer to [`add_method`] for more information about the implementation.
+    ///
+    /// Requires `feature = "async"`
+    ///
+    /// [`add_method`]: #method.add_method
+    #[cfg(feature = "async")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
+    fn add_async_method_mut<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    where
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s mut T, A) -> MR + MaybeSend + 'static,
+        A: FromLuaMulti<'lua>,
+        MR: Future<Output = Result<R>> + 's,
         R: IntoLuaMulti<'lua>;
 
     /// Add a regular method as a function which accepts generic arguments, the first argument will
@@ -349,8 +367,7 @@ pub trait UserDataMethods<'lua, T> {
         A: FromLuaMulti<'lua>,
         R: IntoLuaMulti<'lua>;
 
-    /// Add an async metamethod which accepts a `T` as the first parameter and returns Future.
-    /// The passed `T` is cloned from the original value.
+    /// Add an async metamethod which accepts a `&T` as the first parameter and returns Future.
     ///
     /// This is an async version of [`add_meta_method`].
     ///
@@ -359,12 +376,31 @@ pub trait UserDataMethods<'lua, T> {
     /// [`add_meta_method`]: #method.add_meta_method
     #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn add_async_meta_method<M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    fn add_async_meta_method<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
     where
-        T: Clone,
-        M: Fn(&'lua Lua, T, A) -> MR + MaybeSend + 'static,
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s T, A) -> MR + MaybeSend + 'static,
         A: FromLuaMulti<'lua>,
-        MR: Future<Output = Result<R>> + 'lua,
+        MR: Future<Output = Result<R>> + 's,
+        R: IntoLuaMulti<'lua>;
+
+    /// Add an async metamethod which accepts a `&mut T` as the first parameter and returns Future.
+    ///
+    /// This is an async version of [`add_meta_method_mut`].
+    ///
+    /// Requires `feature = "async"`
+    ///
+    /// [`add_meta_method_mut`]: #method.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<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    where
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s mut T, A) -> MR + MaybeSend + 'static,
+        A: FromLuaMulti<'lua>,
+        MR: Future<Output = Result<R>> + 's,
         R: IntoLuaMulti<'lua>;
 
     /// Add a metamethod which accepts generic arguments.
@@ -410,7 +446,7 @@ pub trait UserDataMethods<'lua, T> {
     //
 
     #[doc(hidden)]
-    fn append_methods_from<S>(&mut self, _other: UserDataRegistrar<'lua, S>) {}
+    fn append_methods_from<S>(&mut self, _other: UserDataRegistry<'lua, S>) {}
 }
 
 /// Field registry for [`UserData`] implementors.
@@ -508,7 +544,7 @@ pub trait UserDataFields<'lua, T> {
     //
 
     #[doc(hidden)]
-    fn append_fields_from<S>(&mut self, _other: UserDataRegistrar<'lua, S>) {}
+    fn append_fields_from<S>(&mut self, _other: UserDataRegistry<'lua, S>) {}
 }
 
 /// Trait for custom userdata types.
@@ -718,19 +754,6 @@ impl<T> Deref for UserDataVariant<T> {
     }
 }
 
-#[cfg(feature = "serialize")]
-struct UserDataSerializeError;
-
-#[cfg(feature = "serialize")]
-impl Serialize for UserDataSerializeError {
-    fn serialize<S>(&self, _serializer: S) -> StdResult<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        Err(ser::Error::custom("cannot serialize <userdata>"))
-    }
-}
-
 /// Handle to an internal Lua userdata for any type that implements [`UserData`].
 ///
 /// Similar to `std::any::Any`, this provides an interface for dynamic type checking via the [`is`]
@@ -826,11 +849,11 @@ impl<'lua> AnyUserData<'lua> {
 
     /// Sets an associated value to this `AnyUserData`.
     ///
-    /// The value may be any Lua value whatsoever, and can be retrieved with [`get_user_value`].
+    /// The value may be any Lua value whatsoever, and can be retrieved with [`user_value`].
     ///
     /// This is the same as calling [`set_nth_user_value`] with `n` set to 1.
     ///
-    /// [`get_user_value`]: #method.get_user_value
+    /// [`user_value`]: #method.user_value
     /// [`set_nth_user_value`]: #method.set_nth_user_value
     #[inline]
     pub fn set_user_value<V: IntoLua<'lua>>(&self, v: V) -> Result<()> {
@@ -839,30 +862,34 @@ impl<'lua> AnyUserData<'lua> {
 
     /// Returns an associated value set by [`set_user_value`].
     ///
-    /// This is the same as calling [`get_nth_user_value`] with `n` set to 1.
+    /// This is the same as calling [`nth_user_value`] with `n` set to 1.
     ///
     /// [`set_user_value`]: #method.set_user_value
-    /// [`get_nth_user_value`]: #method.get_nth_user_value
+    /// [`nth_user_value`]: #method.nth_user_value
     #[inline]
+    pub fn user_value<V: FromLua<'lua>>(&self) -> Result<V> {
+        self.nth_user_value(1)
+    }
+
+    #[doc(hidden)]
+    #[deprecated(since = "0.9.0", note = "please use `user_value` instead")]
     pub fn get_user_value<V: FromLua<'lua>>(&self) -> Result<V> {
-        self.get_nth_user_value(1)
+        self.nth_user_value(1)
     }
 
     /// Sets an associated `n`th value to this `AnyUserData`.
     ///
-    /// The value may be any Lua value whatsoever, and can be retrieved with [`get_nth_user_value`].
+    /// The value may be any Lua value whatsoever, and can be retrieved with [`nth_user_value`].
     /// `n` starts from 1 and can be up to 65535.
     ///
     /// This is supported for all Lua versions.
     /// In Lua 5.4 first 7 elements are stored in a most efficient way.
     /// For other Lua versions this functionality is provided using a wrapping table.
     ///
-    /// [`get_nth_user_value`]: #method.get_nth_user_value
+    /// [`nth_user_value`]: #method.nth_user_value
     pub fn set_nth_user_value<V: IntoLua<'lua>>(&self, n: usize, v: V) -> Result<()> {
         if n < 1 || n > u16::MAX as usize {
-            return Err(Error::RuntimeError(
-                "user value index out of bounds".to_string(),
-            ));
+            return Err(Error::runtime("user value index out of bounds"));
         }
 
         let lua = self.0.lua;
@@ -913,11 +940,9 @@ impl<'lua> AnyUserData<'lua> {
     /// For other Lua versions this functionality is provided using a wrapping table.
     ///
     /// [`set_nth_user_value`]: #method.set_nth_user_value
-    pub fn get_nth_user_value<V: FromLua<'lua>>(&self, n: usize) -> Result<V> {
+    pub fn nth_user_value<V: FromLua<'lua>>(&self, n: usize) -> Result<V> {
         if n < 1 || n > u16::MAX as usize {
-            return Err(Error::RuntimeError(
-                "user value index out of bounds".to_string(),
-            ));
+            return Err(Error::runtime("user value index out of bounds"));
         }
 
         let lua = self.0.lua;
@@ -950,18 +975,20 @@ impl<'lua> AnyUserData<'lua> {
         }
     }
 
+    #[doc(hidden)]
+    #[deprecated(since = "0.9.0", note = "please use `nth_user_value` instead")]
+    pub fn get_nth_user_value<V: FromLua<'lua>>(&self, n: usize) -> Result<V> {
+        self.nth_user_value(n)
+    }
+
     /// Sets an associated value to this `AnyUserData` by name.
     ///
-    /// The value can be retrieved with [`get_named_user_value`].
+    /// The value can be retrieved with [`named_user_value`].
     ///
-    /// [`get_named_user_value`]: #method.get_named_user_value
-    pub fn set_named_user_value<V>(&self, name: impl AsRef<str>, v: V) -> Result<()>
-    where
-        V: IntoLua<'lua>,
-    {
+    /// [`named_user_value`]: #method.named_user_value
+    pub fn set_named_user_value<V: IntoLua<'lua>>(&self, name: &str, v: V) -> Result<()> {
         let lua = self.0.lua;
         let state = lua.state();
-        let name = name.as_ref();
         unsafe {
             let _sg = StackGuard::new(state);
             check_stack(state, 5)?;
@@ -994,13 +1021,9 @@ impl<'lua> AnyUserData<'lua> {
     /// Returns an associated value by name set by [`set_named_user_value`].
     ///
     /// [`set_named_user_value`]: #method.set_named_user_value
-    pub fn get_named_user_value<V>(&self, name: impl AsRef<str>) -> Result<V>
-    where
-        V: FromLua<'lua>,
-    {
+    pub fn named_user_value<V: FromLua<'lua>>(&self, name: &str) -> Result<V> {
         let lua = self.0.lua;
         let state = lua.state();
-        let name = name.as_ref();
         unsafe {
             let _sg = StackGuard::new(state);
             check_stack(state, 4)?;
@@ -1021,6 +1044,12 @@ impl<'lua> AnyUserData<'lua> {
         }
     }
 
+    #[doc(hidden)]
+    #[deprecated(since = "0.9.0", note = "please use `named_user_value` instead")]
+    pub fn get_named_user_value<V: FromLua<'lua>>(&self, name: &str) -> Result<V> {
+        self.named_user_value(name)
+    }
+
     /// Returns a metatable of this `UserData`.
     ///
     /// Returned [`UserDataMetatable`] object wraps the original metatable and
@@ -1055,6 +1084,11 @@ impl<'lua> AnyUserData<'lua> {
         OwnedAnyUserData(self.0.into_owned())
     }
 
+    #[inline(always)]
+    pub(crate) fn type_id(&self) -> Result<Option<TypeId>> {
+        unsafe { self.0.lua.get_userdata_type_id(&self.0) }
+    }
+
     /// Returns a type name of this `UserData` (from `__name` metatable field).
     pub(crate) fn type_name(&self) -> Result<Option<StdString>> {
         let lua = self.0.lua;
@@ -1104,15 +1138,11 @@ impl<'lua> AnyUserData<'lua> {
     #[cfg(feature = "serialize")]
     pub(crate) fn is_serializable(&self) -> bool {
         let lua = self.0.lua;
-        let state = lua.state();
         let is_serializable = || unsafe {
-            let _sg = StackGuard::new(state);
-            check_stack(state, 2)?;
-
             // Userdata can be unregistered or destructed
-            lua.push_userdata_ref(&self.0)?;
+            let _ = lua.get_userdata_type_id(&self.0)?;
 
-            let ud = &*get_userdata::<UserDataCell<()>>(state, -1);
+            let ud = &*get_userdata::<UserDataCell<()>>(lua.ref_thread(), self.0.index);
             match &*ud.0.try_borrow().map_err(|_| Error::UserDataBorrowError)? {
                 UserDataVariant::Serializable(_) => Result::Ok(true),
                 _ => Result::Ok(false),
@@ -1127,15 +1157,12 @@ impl<'lua> AnyUserData<'lua> {
         F: FnOnce(&'a UserDataCell<T>) -> Result<R>,
     {
         let lua = self.0.lua;
-        let state = lua.state();
         unsafe {
-            let _sg = StackGuard::new(state);
-            check_stack(state, 2)?;
-
-            let type_id = lua.push_userdata_ref(&self.0)?;
+            let type_id = lua.get_userdata_type_id(&self.0)?;
             match type_id {
                 Some(type_id) if type_id == TypeId::of::<T>() => {
-                    func(&*get_userdata::<UserDataCell<T>>(state, -1))
+                    let ref_thread = lua.ref_thread();
+                    func(&*get_userdata::<UserDataCell<T>>(ref_thread, self.0.index))
                 }
                 _ => Err(Error::UserDataTypeMismatch),
             }
@@ -1278,19 +1305,17 @@ impl<'lua> Serialize for AnyUserData<'lua> {
         S: Serializer,
     {
         let lua = self.0.lua;
-        let state = lua.state();
         let data = unsafe {
-            let _sg = StackGuard::new(state);
-            check_stack(state, 3).map_err(ser::Error::custom)?;
-
-            lua.push_userdata_ref(&self.0).map_err(ser::Error::custom)?;
-            let ud = &*get_userdata::<UserDataCell<()>>(state, -1);
+            let _ = lua
+                .get_userdata_type_id(&self.0)
+                .map_err(ser::Error::custom)?;
+            let ud = &*get_userdata::<UserDataCell<()>>(lua.ref_thread(), self.0.index);
             ud.0.try_borrow()
                 .map_err(|_| ser::Error::custom(Error::UserDataBorrowError))?
         };
         match &*data {
             UserDataVariant::Serializable(ser) => ser.serialize(serializer),
-            _ => UserDataSerializeError.serialize(serializer),
+            _ => Err(ser::Error::custom("cannot serialize <userdata>")),
         }
     }
 }
@@ -1345,6 +1370,27 @@ impl<'lua, T: 'static> UserDataRefMut<'lua, T> {
     }
 }
 
+pub(crate) struct WrappedUserdata<F: for<'lua> FnOnce(&'lua Lua) -> Result<AnyUserData<'lua>>>(F);
+
+impl<'lua> AnyUserData<'lua> {
+    /// 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<'lua> {
+        WrappedUserdata(move |lua| lua.create_any_userdata(data))
+    }
+}
+
+impl<'lua, F> IntoLua<'lua> for WrappedUserdata<F>
+where
+    F: for<'l> FnOnce(&'l Lua) -> Result<AnyUserData<'l>>,
+{
+    fn into_lua(self, lua: &'lua Lua) -> Result<Value<'lua>> {
+        (self.0)(lua).map(Value::UserData)
+    }
+}
+
+#[inline]
 fn try_value_to_userdata<T>(value: Value) -> Result<AnyUserData> {
     match value {
         Value::UserData(ud) => Ok(ud),

src/userdata_ext.rs

@@ -27,15 +27,14 @@ pub trait AnyUserDataExt<'lua>: Sealed {
     /// The metamethod is called with the userdata as its first argument, followed by the passed arguments.
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn call_async<'fut, A, R>(&self, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async<A, R>(&self, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut;
+        R: FromLuaMulti<'lua> + 'lua;
 
     /// Calls the userdata method, assuming it has `__index` metamethod
     /// and a function associated to `name`.
-    fn call_method<A, R>(&self, name: impl AsRef<str>, args: A) -> Result<R>
+    fn call_method<A, R>(&self, name: &str, args: A) -> Result<R>
     where
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>;
@@ -48,15 +47,10 @@ pub trait AnyUserDataExt<'lua>: Sealed {
     /// This might invoke the `__index` metamethod.
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn call_async_method<'fut, A, R>(
-        &self,
-        name: impl AsRef<str>,
-        args: A,
-    ) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_method<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut;
+        R: FromLuaMulti<'lua> + 'lua;
 
     /// Gets the function associated to `key` from the table and executes it,
     /// passing `args` as function arguments.
@@ -65,7 +59,7 @@ pub trait AnyUserDataExt<'lua>: Sealed {
     /// `table.get::<_, Function>(key)?.call(args)`
     ///
     /// This might invoke the `__index` metamethod.
-    fn call_function<A, R>(&self, name: impl AsRef<str>, args: A) -> Result<R>
+    fn call_function<A, R>(&self, name: &str, args: A) -> Result<R>
     where
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>;
@@ -78,15 +72,10 @@ pub trait AnyUserDataExt<'lua>: Sealed {
     /// This might invoke the `__index` metamethod.
     #[cfg(feature = "async")]
     #[cfg_attr(docsrs, doc(cfg(feature = "async")))]
-    fn call_async_function<'fut, A, R>(
-        &self,
-        name: impl AsRef<str>,
-        args: A,
-    ) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_function<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut;
+        R: FromLuaMulti<'lua> + 'lua;
 }
 
 impl<'lua> AnyUserDataExt<'lua> for AnyUserData<'lua> {
@@ -95,9 +84,7 @@ impl<'lua> AnyUserDataExt<'lua> for AnyUserData<'lua> {
         match metatable.get::<Value>(MetaMethod::Index)? {
             Value::Table(table) => table.raw_get(key),
             Value::Function(func) => func.call((self.clone(), key)),
-            _ => Err(Error::RuntimeError(
-                "attempt to index a userdata value".to_string(),
-            )),
+            _ => Err(Error::runtime("attempt to index a userdata value")),
         }
     }
 
@@ -106,9 +93,7 @@ impl<'lua> AnyUserDataExt<'lua> for AnyUserData<'lua> {
         match metatable.get::<Value>(MetaMethod::NewIndex)? {
             Value::Table(table) => table.raw_set(key, value),
             Value::Function(func) => func.call((self.clone(), key, value)),
-            _ => Err(Error::RuntimeError(
-                "attempt to index a userdata value".to_string(),
-            )),
+            _ => Err(Error::runtime("attempt to index a userdata value")),
         }
     }
 
@@ -120,33 +105,37 @@ impl<'lua> AnyUserDataExt<'lua> for AnyUserData<'lua> {
         let metatable = self.get_metatable()?;
         match metatable.get::<Value>(MetaMethod::Call)? {
             Value::Function(func) => func.call((self.clone(), args)),
-            _ => Err(Error::RuntimeError(
-                "attempt to call a userdata value".to_string(),
-            )),
+            _ => Err(Error::runtime("attempt to call a userdata value")),
         }
     }
 
     #[cfg(feature = "async")]
-    fn call_async<'fut, A, R>(&self, args: A) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async<A, R>(&self, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
         let metatable = match self.get_metatable() {
             Ok(metatable) => metatable,
             Err(err) => return Box::pin(future::err(err)),
         };
         match metatable.get::<Value>(MetaMethod::Call) {
-            Ok(Value::Function(func)) => func.call_async((self.clone(), args)),
-            Ok(_) => Box::pin(future::err(Error::RuntimeError(
-                "attempt to call a userdata value".to_string(),
+            Ok(Value::Function(func)) => {
+                let mut args = match args.into_lua_multi(self.0.lua) {
+                    Ok(args) => args,
+                    Err(e) => return Box::pin(future::err(e)),
+                };
+                args.push_front(Value::UserData(self.clone()));
+                Box::pin(async move { func.call_async(args).await })
+            }
+            Ok(_) => Box::pin(future::err(Error::runtime(
+                "attempt to call a userdata value",
             ))),
             Err(err) => Box::pin(future::err(err)),
         }
     }
 
-    fn call_method<A, R>(&self, name: impl AsRef<str>, args: A) -> Result<R>
+    fn call_method<A, R>(&self, name: &str, args: A) -> Result<R>
     where
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>,
@@ -155,50 +144,46 @@ impl<'lua> AnyUserDataExt<'lua> for AnyUserData<'lua> {
     }
 
     #[cfg(feature = "async")]
-    fn call_async_method<'fut, A, R>(
-        &self,
-        name: impl AsRef<str>,
-        args: A,
-    ) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_method<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
         self.call_async_function(name, (self.clone(), args))
     }
 
-    fn call_function<A, R>(&self, name: impl AsRef<str>, args: A) -> Result<R>
+    fn call_function<A, R>(&self, name: &str, args: A) -> Result<R>
     where
         A: IntoLuaMulti<'lua>,
         R: FromLuaMulti<'lua>,
     {
-        match self.get(name.as_ref())? {
+        match self.get(name)? {
             Value::Function(func) => func.call(args),
-            val => Err(Error::RuntimeError(format!(
-                "attempt to call a {} value",
-                val.type_name()
-            ))),
+            val => {
+                let msg = format!("attempt to call a {} value", val.type_name());
+                Err(Error::runtime(msg))
+            }
         }
     }
 
     #[cfg(feature = "async")]
-    fn call_async_function<'fut, A, R>(
-        &self,
-        name: impl AsRef<str>,
-        args: A,
-    ) -> LocalBoxFuture<'fut, Result<R>>
+    fn call_async_function<A, R>(&self, name: &str, args: A) -> LocalBoxFuture<'lua, Result<R>>
     where
-        'lua: 'fut,
         A: IntoLuaMulti<'lua>,
-        R: FromLuaMulti<'lua> + 'fut,
+        R: FromLuaMulti<'lua> + 'lua,
     {
-        match self.get(name.as_ref()) {
-            Ok(Value::Function(func)) => func.call_async(args),
-            Ok(val) => Box::pin(future::err(Error::RuntimeError(format!(
-                "attempt to call a {} value",
-                val.type_name()
-            )))),
+        match self.get(name) {
+            Ok(Value::Function(func)) => {
+                let args = match args.into_lua_multi(self.0.lua) {
+                    Ok(args) => args,
+                    Err(e) => return Box::pin(future::err(e)),
+                };
+                Box::pin(async move { func.call_async(args).await })
+            }
+            Ok(val) => {
+                let msg = format!("attempt to call a {} value", val.type_name());
+                Box::pin(future::err(Error::runtime(msg)))
+            }
             Err(err) => Box::pin(future::err(err)),
         }
     }

src/userdata_impl.rs

@@ -1,6 +1,9 @@
+#![allow(clippy::await_holding_refcell_ref, clippy::await_holding_lock)]
+
 use std::any::TypeId;
 use std::cell::{Ref, RefCell, RefMut};
 use std::marker::PhantomData;
+use std::os::raw::c_int;
 use std::string::String as StdString;
 use std::sync::{Arc, Mutex, RwLock};
 
@@ -10,7 +13,7 @@ use crate::types::{Callback, MaybeSend};
 use crate::userdata::{
     AnyUserData, MetaMethod, UserData, UserDataCell, UserDataFields, UserDataMethods,
 };
-use crate::util::{check_stack, get_userdata, short_type_name, StackGuard};
+use crate::util::{get_userdata, short_type_name};
 use crate::value::{FromLua, FromLuaMulti, IntoLua, IntoLuaMulti, MultiValue, Value};
 
 #[cfg(not(feature = "send"))]
@@ -23,7 +26,8 @@ use {
     std::future::Future,
 };
 
-pub struct UserDataRegistrar<'lua, T: 'static> {
+/// Handle to registry for userdata methods and metamethods.
+pub struct UserDataRegistry<'lua, T: 'static> {
     // Fields
     pub(crate) fields: Vec<(String, Callback<'lua, 'static>)>,
     pub(crate) field_getters: Vec<(String, Callback<'lua, 'static>)>,
@@ -41,9 +45,9 @@ pub struct UserDataRegistrar<'lua, T: 'static> {
     _type: PhantomData<T>,
 }
 
-impl<'lua, T: 'static> UserDataRegistrar<'lua, T> {
+impl<'lua, T: 'static> UserDataRegistry<'lua, T> {
     pub(crate) const fn new() -> Self {
-        UserDataRegistrar {
+        UserDataRegistry {
             fields: Vec::new(),
             field_getters: Vec::new(),
             field_setters: Vec::new(),
@@ -75,62 +79,63 @@ impl<'lua, T: 'static> UserDataRegistrar<'lua, T> {
         }
 
         Box::new(move |lua, mut args| {
-            let front = args.pop_front();
+            let front = args
+                .pop_front()
+                .ok_or_else(|| Error::from_lua_conversion("missing argument", "userdata", None));
+            let front = try_self_arg!(front);
             let call = |ud| {
                 // Self was at index 1, so we pass 2 here
                 let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
                 method(lua, ud, args)?.into_lua_multi(lua)
             };
 
-            if let Some(front) = front {
-                let state = lua.state();
-                let userdata = try_self_arg!(AnyUserData::from_lua(front, lua));
-                unsafe {
-                    let _sg = StackGuard::new(state);
-                    check_stack(state, 2)?;
-
-                    let type_id = try_self_arg!(lua.push_userdata_ref(&userdata.0));
-                    match type_id {
-                        Some(id) if id == TypeId::of::<T>() => {
-                            let ud = try_self_arg!(get_userdata_ref::<T>(state));
-                            call(&ud)
-                        }
-                        #[cfg(not(feature = "send"))]
-                        Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => {
-                            let ud = try_self_arg!(get_userdata_ref::<Rc<RefCell<T>>>(state));
-                            let ud = try_self_arg!(ud.try_borrow(), Error::UserDataBorrowError);
-                            call(&ud)
-                        }
-                        Some(id) if id == TypeId::of::<Arc<Mutex<T>>>() => {
-                            let ud = try_self_arg!(get_userdata_ref::<Arc<Mutex<T>>>(state));
-                            let ud = try_self_arg!(ud.try_lock(), Error::UserDataBorrowError);
-                            call(&ud)
-                        }
-                        #[cfg(feature = "parking_lot")]
-                        Some(id) if id == TypeId::of::<Arc<parking_lot::Mutex<T>>>() => {
-                            let ud = get_userdata_ref::<Arc<parking_lot::Mutex<T>>>(state);
-                            let ud = try_self_arg!(ud);
-                            let ud = try_self_arg!(ud.try_lock().ok_or(Error::UserDataBorrowError));
-                            call(&ud)
-                        }
-                        Some(id) if id == TypeId::of::<Arc<RwLock<T>>>() => {
-                            let ud = try_self_arg!(get_userdata_ref::<Arc<RwLock<T>>>(state));
-                            let ud = try_self_arg!(ud.try_read(), Error::UserDataBorrowError);
-                            call(&ud)
-                        }
-                        #[cfg(feature = "parking_lot")]
-                        Some(id) if id == TypeId::of::<Arc<parking_lot::RwLock<T>>>() => {
-                            let ud = get_userdata_ref::<Arc<parking_lot::RwLock<T>>>(state);
-                            let ud = try_self_arg!(ud);
-                            let ud = try_self_arg!(ud.try_read().ok_or(Error::UserDataBorrowError));
-                            call(&ud)
-                        }
-                        _ => Err(Error::bad_self_argument(&name, Error::UserDataTypeMismatch)),
-                    }
-                }
-            } else {
-                let err = Error::from_lua_conversion("missing argument", "userdata", None);
-                Err(Error::bad_self_argument(&name, err))
+            let userdata = try_self_arg!(AnyUserData::from_lua(front, lua));
+            let (ref_thread, index) = (lua.ref_thread(), userdata.0.index);
+            match try_self_arg!(userdata.type_id()) {
+                Some(id) if id == TypeId::of::<T>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_ref::<T>(ref_thread, index));
+                    call(&ud)
+                },
+                #[cfg(not(feature = "send"))]
+                Some(id) if id == TypeId::of::<Rc<T>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_ref::<Rc<T>>(ref_thread, index));
+                    call(&ud)
+                },
+                #[cfg(not(feature = "send"))]
+                Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_ref::<Rc<RefCell<T>>>(ref_thread, index));
+                    let ud = try_self_arg!(ud.try_borrow(), Error::UserDataBorrowError);
+                    call(&ud)
+                },
+                Some(id) if id == TypeId::of::<Arc<T>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_ref::<Arc<T>>(ref_thread, index));
+                    call(&ud)
+                },
+                Some(id) if id == TypeId::of::<Arc<Mutex<T>>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_ref::<Arc<Mutex<T>>>(ref_thread, index));
+                    let ud = try_self_arg!(ud.try_lock(), Error::UserDataBorrowError);
+                    call(&ud)
+                },
+                #[cfg(feature = "parking_lot")]
+                Some(id) if id == TypeId::of::<Arc<parking_lot::Mutex<T>>>() => unsafe {
+                    let ud = get_userdata_ref::<Arc<parking_lot::Mutex<T>>>(ref_thread, index);
+                    let ud = try_self_arg!(ud);
+                    let ud = try_self_arg!(ud.try_lock().ok_or(Error::UserDataBorrowError));
+                    call(&ud)
+                },
+                Some(id) if id == TypeId::of::<Arc<RwLock<T>>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_ref::<Arc<RwLock<T>>>(ref_thread, index));
+                    let ud = try_self_arg!(ud.try_read(), Error::UserDataBorrowError);
+                    call(&ud)
+                },
+                #[cfg(feature = "parking_lot")]
+                Some(id) if id == TypeId::of::<Arc<parking_lot::RwLock<T>>>() => unsafe {
+                    let ud = get_userdata_ref::<Arc<parking_lot::RwLock<T>>>(ref_thread, index);
+                    let ud = try_self_arg!(ud);
+                    let ud = try_self_arg!(ud.try_read().ok_or(Error::UserDataBorrowError));
+                    call(&ud)
+                },
+                _ => Err(Error::bad_self_argument(&name, Error::UserDataTypeMismatch)),
             }
         })
     }
@@ -156,158 +161,258 @@ impl<'lua, T: 'static> UserDataRegistrar<'lua, T> {
             let mut method = method
                 .try_borrow_mut()
                 .map_err(|_| Error::RecursiveMutCallback)?;
-            let front = args.pop_front();
+            let front = args
+                .pop_front()
+                .ok_or_else(|| Error::from_lua_conversion("missing argument", "userdata", None));
+            let front = try_self_arg!(front);
             let call = |ud| {
                 // Self was at index 1, so we pass 2 here
                 let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
                 method(lua, ud, args)?.into_lua_multi(lua)
             };
 
-            if let Some(front) = front {
-                let state = lua.state();
-                let userdata = try_self_arg!(AnyUserData::from_lua(front, lua));
-                unsafe {
-                    let _sg = StackGuard::new(state);
-                    check_stack(state, 2)?;
-
-                    let type_id = try_self_arg!(lua.push_userdata_ref(&userdata.0));
-                    match type_id {
-                        Some(id) if id == TypeId::of::<T>() => {
-                            let mut ud = try_self_arg!(get_userdata_mut::<T>(state));
-                            call(&mut ud)
-                        }
-                        #[cfg(not(feature = "send"))]
-                        Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => {
-                            let ud = try_self_arg!(get_userdata_mut::<Rc<RefCell<T>>>(state));
-                            let mut ud =
-                                try_self_arg!(ud.try_borrow_mut(), Error::UserDataBorrowMutError);
-                            call(&mut ud)
-                        }
-                        Some(id) if id == TypeId::of::<Arc<Mutex<T>>>() => {
-                            let ud = try_self_arg!(get_userdata_mut::<Arc<Mutex<T>>>(state));
-                            let mut ud =
-                                try_self_arg!(ud.try_lock(), Error::UserDataBorrowMutError);
-                            call(&mut ud)
-                        }
-                        #[cfg(feature = "parking_lot")]
-                        Some(id) if id == TypeId::of::<Arc<parking_lot::Mutex<T>>>() => {
-                            let ud = get_userdata_mut::<Arc<parking_lot::Mutex<T>>>(state);
-                            let ud = try_self_arg!(ud);
-                            let mut ud =
-                                try_self_arg!(ud.try_lock().ok_or(Error::UserDataBorrowMutError));
-                            call(&mut ud)
-                        }
-                        Some(id) if id == TypeId::of::<Arc<RwLock<T>>>() => {
-                            let ud = try_self_arg!(get_userdata_mut::<Arc<RwLock<T>>>(state));
-                            let mut ud =
-                                try_self_arg!(ud.try_write(), Error::UserDataBorrowMutError);
-                            call(&mut ud)
-                        }
-                        #[cfg(feature = "parking_lot")]
-                        Some(id) if id == TypeId::of::<Arc<parking_lot::RwLock<T>>>() => {
-                            let ud = get_userdata_mut::<Arc<parking_lot::RwLock<T>>>(state);
-                            let ud = try_self_arg!(ud);
-                            let mut ud =
-                                try_self_arg!(ud.try_write().ok_or(Error::UserDataBorrowMutError));
-                            call(&mut ud)
-                        }
-                        _ => Err(Error::bad_self_argument(&name, Error::UserDataTypeMismatch)),
-                    }
-                }
-            } else {
-                let err = Error::from_lua_conversion("missing argument", "userdata", None);
-                Err(Error::bad_self_argument(&name, err))
+            let userdata = try_self_arg!(AnyUserData::from_lua(front, lua));
+            let (ref_thread, index) = (lua.ref_thread(), userdata.0.index);
+            match try_self_arg!(userdata.type_id()) {
+                Some(id) if id == TypeId::of::<T>() => unsafe {
+                    let mut ud = try_self_arg!(get_userdata_mut::<T>(ref_thread, index));
+                    call(&mut ud)
+                },
+                #[cfg(not(feature = "send"))]
+                Some(id) if id == TypeId::of::<Rc<T>>() => Err(Error::UserDataBorrowMutError),
+                #[cfg(not(feature = "send"))]
+                Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_mut::<Rc<RefCell<T>>>(ref_thread, index));
+                    let mut ud = try_self_arg!(ud.try_borrow_mut(), Error::UserDataBorrowMutError);
+                    call(&mut ud)
+                },
+                Some(id) if id == TypeId::of::<Arc<T>>() => Err(Error::UserDataBorrowMutError),
+                Some(id) if id == TypeId::of::<Arc<Mutex<T>>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_mut::<Arc<Mutex<T>>>(ref_thread, index));
+                    let mut ud = try_self_arg!(ud.try_lock(), Error::UserDataBorrowMutError);
+                    call(&mut ud)
+                },
+                #[cfg(feature = "parking_lot")]
+                Some(id) if id == TypeId::of::<Arc<parking_lot::Mutex<T>>>() => unsafe {
+                    let ud = get_userdata_mut::<Arc<parking_lot::Mutex<T>>>(ref_thread, index);
+                    let ud = try_self_arg!(ud);
+                    let mut ud = try_self_arg!(ud.try_lock().ok_or(Error::UserDataBorrowMutError));
+                    call(&mut ud)
+                },
+                Some(id) if id == TypeId::of::<Arc<RwLock<T>>>() => unsafe {
+                    let ud = try_self_arg!(get_userdata_mut::<Arc<RwLock<T>>>(ref_thread, index));
+                    let mut ud = try_self_arg!(ud.try_write(), Error::UserDataBorrowMutError);
+                    call(&mut ud)
+                },
+                #[cfg(feature = "parking_lot")]
+                Some(id) if id == TypeId::of::<Arc<parking_lot::RwLock<T>>>() => unsafe {
+                    let ud = get_userdata_mut::<Arc<parking_lot::RwLock<T>>>(ref_thread, index);
+                    let ud = try_self_arg!(ud);
+                    let mut ud = try_self_arg!(ud.try_write().ok_or(Error::UserDataBorrowMutError));
+                    call(&mut ud)
+                },
+                _ => Err(Error::bad_self_argument(&name, Error::UserDataTypeMismatch)),
             }
         })
     }
 
     #[cfg(feature = "async")]
-    fn box_async_method<M, A, MR, R>(name: &str, method: M) -> AsyncCallback<'lua, 'static>
+    fn box_async_method<'s, M, A, MR, R>(name: &str, method: M) -> AsyncCallback<'lua, 'static>
     where
-        T: Clone,
-        M: Fn(&'lua Lua, T, A) -> MR + MaybeSend + 'static,
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s T, A) -> MR + MaybeSend + 'static,
         A: FromLuaMulti<'lua>,
-        MR: Future<Output = Result<R>> + 'lua,
+        MR: Future<Output = Result<R>> + 's,
         R: IntoLuaMulti<'lua>,
     {
         let name = get_function_name::<T>(name);
-        macro_rules! try_self_arg {
-            ($res:expr) => {
-                $res.map_err(|err| Error::bad_self_argument(&name, err))?
-            };
-            ($res:expr, $err:expr) => {
-                $res.map_err(|_| Error::bad_self_argument(&name, $err))?
-            };
-        }
+        let method = Arc::new(method);
 
         Box::new(move |lua, mut args| {
-            let front = args.pop_front();
-            let call = |ud| {
-                // Self was at index 1, so we pass 2 here
-                let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
-                Ok(method(lua, ud, args))
-            };
-
-            let fut_res = || {
-                if let Some(front) = front {
-                    let state = lua.state();
-                    let userdata = AnyUserData::from_lua(front, lua)?;
-                    unsafe {
-                        let _sg = StackGuard::new(state);
-                        check_stack(state, 2)?;
-
-                        let type_id = try_self_arg!(lua.push_userdata_ref(&userdata.0));
-                        match type_id {
-                            Some(id) if id == TypeId::of::<T>() => {
-                                let ud = get_userdata_ref::<T>(state)?;
-                                call(ud.clone())
-                            }
-                            #[cfg(not(feature = "send"))]
-                            Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => {
-                                let ud = try_self_arg!(get_userdata_ref::<Rc<RefCell<T>>>(state));
-                                let ud = try_self_arg!(ud.try_borrow(), Error::UserDataBorrowError);
-                                call(ud.clone())
-                            }
-                            Some(id) if id == TypeId::of::<Arc<Mutex<T>>>() => {
-                                let ud = try_self_arg!(get_userdata_ref::<Arc<Mutex<T>>>(state));
-                                let ud = try_self_arg!(ud.try_lock(), Error::UserDataBorrowError);
-                                call(ud.clone())
-                            }
-                            #[cfg(feature = "parking_lot")]
-                            Some(id) if id == TypeId::of::<Arc<parking_lot::Mutex<T>>>() => {
-                                let ud = get_userdata_ref::<Arc<parking_lot::Mutex<T>>>(state);
-                                let ud = try_self_arg!(ud);
-                                let ud =
-                                    try_self_arg!(ud.try_lock().ok_or(Error::UserDataBorrowError));
-                                call(ud.clone())
-                            }
-                            Some(id) if id == TypeId::of::<Arc<RwLock<T>>>() => {
-                                let ud = try_self_arg!(get_userdata_ref::<Arc<RwLock<T>>>(state));
-                                let ud = try_self_arg!(ud.try_read(), Error::UserDataBorrowError);
-                                call(ud.clone())
-                            }
-                            #[cfg(feature = "parking_lot")]
-                            Some(id) if id == TypeId::of::<Arc<parking_lot::RwLock<T>>>() => {
-                                let ud = get_userdata_ref::<Arc<parking_lot::RwLock<T>>>(state);
-                                let ud = try_self_arg!(ud);
-                                let ud =
-                                    try_self_arg!(ud.try_read().ok_or(Error::UserDataBorrowError));
-                                call(ud.clone())
-                            }
-                            _ => Err(Error::bad_self_argument(&name, Error::UserDataTypeMismatch)),
-                        }
-                    }
-                } else {
-                    let err = Error::from_lua_conversion("missing argument", "userdata", None);
-                    Err(Error::bad_self_argument(&name, err))
-                }
-            };
-            match fut_res() {
-                Ok(fut) => {
-                    Box::pin(fut.and_then(move |ret| future::ready(ret.into_lua_multi(lua))))
-                }
-                Err(e) => Box::pin(future::err(e)),
+            let name = name.clone();
+            let method = method.clone();
+            macro_rules! try_self_arg {
+                ($res:expr) => {
+                    $res.map_err(|err| Error::bad_self_argument(&name, err))?
+                };
+                ($res:expr, $err:expr) => {
+                    $res.map_err(|_| Error::bad_self_argument(&name, $err))?
+                };
             }
+
+            Box::pin(async move {
+                let front = args.pop_front().ok_or_else(|| {
+                    Error::from_lua_conversion("missing argument", "userdata", None)
+                });
+                let front = try_self_arg!(front);
+                let userdata: AnyUserData = try_self_arg!(AnyUserData::from_lua(front, lua));
+                let (ref_thread, index) = (lua.ref_thread(), userdata.0.index);
+                match try_self_arg!(userdata.type_id()) {
+                    Some(id) if id == TypeId::of::<T>() => unsafe {
+                        let ud = try_self_arg!(get_userdata_ref::<T>(ref_thread, index));
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        // Self was at index 1, so we pass 2 here
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(not(feature = "send"))]
+                    Some(id) if id == TypeId::of::<Rc<T>>() => unsafe {
+                        let ud = try_self_arg!(get_userdata_ref::<Rc<T>>(ref_thread, index));
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(not(feature = "send"))]
+                    Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => unsafe {
+                        let ud =
+                            try_self_arg!(get_userdata_ref::<Rc<RefCell<T>>>(ref_thread, index));
+                        let ud = try_self_arg!(ud.try_borrow(), Error::UserDataBorrowError);
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    Some(id) if id == TypeId::of::<Arc<T>>() => unsafe {
+                        let ud = try_self_arg!(get_userdata_ref::<Arc<T>>(ref_thread, index));
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    Some(id) if id == TypeId::of::<Arc<Mutex<T>>>() => unsafe {
+                        let ud =
+                            try_self_arg!(get_userdata_ref::<Arc<Mutex<T>>>(ref_thread, index));
+                        let ud = try_self_arg!(ud.try_lock(), Error::UserDataBorrowError);
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(feature = "parking_lot")]
+                    Some(id) if id == TypeId::of::<Arc<parking_lot::Mutex<T>>>() => unsafe {
+                        let ud = get_userdata_ref::<Arc<parking_lot::Mutex<T>>>(ref_thread, index);
+                        let ud = try_self_arg!(ud);
+                        let ud = try_self_arg!(ud.try_lock().ok_or(Error::UserDataBorrowError));
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    Some(id) if id == TypeId::of::<Arc<RwLock<T>>>() => unsafe {
+                        let ud =
+                            try_self_arg!(get_userdata_ref::<Arc<RwLock<T>>>(ref_thread, index));
+                        let ud = try_self_arg!(ud.try_read(), Error::UserDataBorrowError);
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(feature = "parking_lot")]
+                    Some(id) if id == TypeId::of::<Arc<parking_lot::RwLock<T>>>() => unsafe {
+                        let ud = get_userdata_ref::<Arc<parking_lot::RwLock<T>>>(ref_thread, index);
+                        let ud = try_self_arg!(ud);
+                        let ud = try_self_arg!(ud.try_read().ok_or(Error::UserDataBorrowError));
+                        let ud = std::mem::transmute::<&T, &T>(&ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    _ => Err(Error::bad_self_argument(&name, Error::UserDataTypeMismatch)),
+                }
+            })
+        })
+    }
+
+    #[cfg(feature = "async")]
+    fn box_async_method_mut<'s, M, A, MR, R>(name: &str, method: M) -> AsyncCallback<'lua, 'static>
+    where
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s mut T, A) -> MR + MaybeSend + 'static,
+        A: FromLuaMulti<'lua>,
+        MR: Future<Output = Result<R>> + 's,
+        R: IntoLuaMulti<'lua>,
+    {
+        let name = get_function_name::<T>(name);
+        let method = Arc::new(method);
+
+        Box::new(move |lua, mut args| {
+            let name = name.clone();
+            let method = method.clone();
+            macro_rules! try_self_arg {
+                ($res:expr) => {
+                    $res.map_err(|err| Error::bad_self_argument(&name, err))?
+                };
+                ($res:expr, $err:expr) => {
+                    $res.map_err(|_| Error::bad_self_argument(&name, $err))?
+                };
+            }
+
+            Box::pin(async move {
+                let front = args.pop_front().ok_or_else(|| {
+                    Error::from_lua_conversion("missing argument", "userdata", None)
+                });
+                let front = try_self_arg!(front);
+                let userdata: AnyUserData = try_self_arg!(AnyUserData::from_lua(front, lua));
+                let (ref_thread, index) = (lua.ref_thread(), userdata.0.index);
+                match try_self_arg!(userdata.type_id()) {
+                    Some(id) if id == TypeId::of::<T>() => unsafe {
+                        let mut ud = try_self_arg!(get_userdata_mut::<T>(ref_thread, index));
+                        let ud = std::mem::transmute::<&mut T, &mut T>(&mut ud);
+                        // Self was at index 1, so we pass 2 here
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(not(feature = "send"))]
+                    Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => {
+                        Err(Error::UserDataBorrowMutError)
+                    }
+                    #[cfg(not(feature = "send"))]
+                    Some(id) if id == TypeId::of::<Rc<RefCell<T>>>() => unsafe {
+                        let ud =
+                            try_self_arg!(get_userdata_mut::<Rc<RefCell<T>>>(ref_thread, index));
+                        let mut ud =
+                            try_self_arg!(ud.try_borrow_mut(), Error::UserDataBorrowMutError);
+                        let ud = std::mem::transmute::<&mut T, &mut T>(&mut ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(not(feature = "send"))]
+                    Some(id) if id == TypeId::of::<Arc<T>>() => Err(Error::UserDataBorrowMutError),
+                    Some(id) if id == TypeId::of::<Arc<Mutex<T>>>() => unsafe {
+                        let ud =
+                            try_self_arg!(get_userdata_mut::<Arc<Mutex<T>>>(ref_thread, index));
+                        let mut ud = try_self_arg!(ud.try_lock(), Error::UserDataBorrowMutError);
+                        let ud = std::mem::transmute::<&mut T, &mut T>(&mut ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(feature = "parking_lot")]
+                    Some(id) if id == TypeId::of::<Arc<parking_lot::Mutex<T>>>() => unsafe {
+                        let ud = get_userdata_mut::<Arc<parking_lot::Mutex<T>>>(ref_thread, index);
+                        let ud = try_self_arg!(ud);
+                        let mut ud =
+                            try_self_arg!(ud.try_lock().ok_or(Error::UserDataBorrowMutError));
+                        let ud = std::mem::transmute::<&mut T, &mut T>(&mut ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    Some(id) if id == TypeId::of::<Arc<RwLock<T>>>() => unsafe {
+                        let ud =
+                            try_self_arg!(get_userdata_mut::<Arc<RwLock<T>>>(ref_thread, index));
+                        let mut ud = try_self_arg!(ud.try_write(), Error::UserDataBorrowMutError);
+                        let ud = std::mem::transmute::<&mut T, &mut T>(&mut ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    #[cfg(feature = "parking_lot")]
+                    Some(id) if id == TypeId::of::<Arc<parking_lot::RwLock<T>>>() => unsafe {
+                        let ud = get_userdata_mut::<Arc<parking_lot::RwLock<T>>>(ref_thread, index);
+                        let ud = try_self_arg!(ud);
+                        let mut ud =
+                            try_self_arg!(ud.try_write().ok_or(Error::UserDataBorrowMutError));
+                        let ud = std::mem::transmute::<&mut T, &mut T>(&mut ud);
+                        let args = A::from_lua_multi_args(args, 2, Some(&name), lua)?;
+                        method(lua, ud, args).await?.into_lua_multi(lua)
+                    },
+                    _ => Err(Error::bad_self_argument(&name, Error::UserDataTypeMismatch)),
+                }
+            })
         })
     }
 
@@ -389,7 +494,7 @@ fn get_function_name<T>(name: &str) -> StdString {
     format!("{}.{name}", short_type_name::<T>())
 }
 
-impl<'lua, T: 'static> UserDataFields<'lua, T> for UserDataRegistrar<'lua, T> {
+impl<'lua, T: 'static> UserDataFields<'lua, T> for UserDataRegistry<'lua, T> {
     fn add_field<V>(&mut self, name: impl AsRef<str>, value: V)
     where
         V: IntoLua<'lua> + Clone + 'static,
@@ -468,7 +573,7 @@ impl<'lua, T: 'static> UserDataFields<'lua, T> for UserDataRegistrar<'lua, T> {
 
     // Below are internal methods
 
-    fn append_fields_from<S>(&mut self, other: UserDataRegistrar<'lua, S>) {
+    fn append_fields_from<S>(&mut self, other: UserDataRegistry<'lua, S>) {
         self.fields.extend(other.fields);
         self.field_getters.extend(other.field_getters);
         self.field_setters.extend(other.field_setters);
@@ -476,7 +581,7 @@ impl<'lua, T: 'static> UserDataFields<'lua, T> for UserDataRegistrar<'lua, T> {
     }
 }
 
-impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistrar<'lua, T> {
+impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistry<'lua, T> {
     fn add_method<M, A, R>(&mut self, name: impl AsRef<str>, method: M)
     where
         M: Fn(&'lua Lua, &T, A) -> Result<R> + MaybeSend + 'static,
@@ -500,12 +605,13 @@ impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistrar<'lua, T> {
     }
 
     #[cfg(feature = "async")]
-    fn add_async_method<M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    fn add_async_method<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
     where
-        T: Clone,
-        M: Fn(&'lua Lua, T, A) -> MR + MaybeSend + 'static,
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s T, A) -> MR + MaybeSend + 'static,
         A: FromLuaMulti<'lua>,
-        MR: Future<Output = Result<R>> + 'lua,
+        MR: Future<Output = Result<R>> + 's,
         R: IntoLuaMulti<'lua>,
     {
         let name = name.as_ref();
@@ -513,6 +619,21 @@ impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistrar<'lua, T> {
             .push((name.into(), Self::box_async_method(name, method)));
     }
 
+    #[cfg(feature = "async")]
+    fn add_async_method_mut<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    where
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s mut T, A) -> MR + MaybeSend + 'static,
+        A: FromLuaMulti<'lua>,
+        MR: Future<Output = Result<R>> + 's,
+        R: IntoLuaMulti<'lua>,
+    {
+        let name = name.as_ref();
+        self.async_methods
+            .push((name.into(), Self::box_async_method_mut(name, method)));
+    }
+
     fn add_function<F, A, R>(&mut self, name: impl AsRef<str>, function: F)
     where
         F: Fn(&'lua Lua, A) -> Result<R> + MaybeSend + 'static,
@@ -571,12 +692,13 @@ impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistrar<'lua, T> {
     }
 
     #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
-    fn add_async_meta_method<M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    fn add_async_meta_method<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
     where
-        T: Clone,
-        M: Fn(&'lua Lua, T, A) -> MR + MaybeSend + 'static,
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s T, A) -> MR + MaybeSend + 'static,
         A: FromLuaMulti<'lua>,
-        MR: Future<Output = Result<R>> + 'lua,
+        MR: Future<Output = Result<R>> + 's,
         R: IntoLuaMulti<'lua>,
     {
         let name = name.as_ref();
@@ -584,6 +706,21 @@ impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistrar<'lua, T> {
             .push((name.into(), Self::box_async_method(name, method)));
     }
 
+    #[cfg(all(feature = "async", not(any(feature = "lua51", feature = "luau"))))]
+    fn add_async_meta_method_mut<'s, M, A, MR, R>(&mut self, name: impl AsRef<str>, method: M)
+    where
+        'lua: 's,
+        T: 'static,
+        M: Fn(&'lua Lua, &'s mut T, A) -> MR + MaybeSend + 'static,
+        A: FromLuaMulti<'lua>,
+        MR: Future<Output = Result<R>> + 's,
+        R: IntoLuaMulti<'lua>,
+    {
+        let name = name.as_ref();
+        self.async_meta_methods
+            .push((name.into(), Self::box_async_method_mut(name, method)));
+    }
+
     fn add_meta_function<F, A, R>(&mut self, name: impl AsRef<str>, function: F)
     where
         F: Fn(&'lua Lua, A) -> Result<R> + MaybeSend + 'static,
@@ -621,7 +758,7 @@ impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistrar<'lua, T> {
 
     // Below are internal methods used in generated code
 
-    fn append_methods_from<S>(&mut self, other: UserDataRegistrar<'lua, S>) {
+    fn append_methods_from<S>(&mut self, other: UserDataRegistry<'lua, S>) {
         self.methods.extend(other.methods);
         #[cfg(feature = "async")]
         self.async_methods.extend(other.async_methods);
@@ -632,26 +769,29 @@ impl<'lua, T: 'static> UserDataMethods<'lua, T> for UserDataRegistrar<'lua, T> {
 }
 
 #[inline]
-unsafe fn get_userdata_ref<'a, T>(state: *mut ffi::lua_State) -> Result<Ref<'a, T>> {
-    (*get_userdata::<UserDataCell<T>>(state, -1)).try_borrow()
+unsafe fn get_userdata_ref<'a, T>(state: *mut ffi::lua_State, index: c_int) -> Result<Ref<'a, T>> {
+    (*get_userdata::<UserDataCell<T>>(state, index)).try_borrow()
 }
 
 #[inline]
-unsafe fn get_userdata_mut<'a, T>(state: *mut ffi::lua_State) -> Result<RefMut<'a, T>> {
-    (*get_userdata::<UserDataCell<T>>(state, -1)).try_borrow_mut()
+unsafe fn get_userdata_mut<'a, T>(
+    state: *mut ffi::lua_State,
+    index: c_int,
+) -> Result<RefMut<'a, T>> {
+    (*get_userdata::<UserDataCell<T>>(state, index)).try_borrow_mut()
 }
 
 macro_rules! lua_userdata_impl {
     ($type:ty) => {
         impl<T: UserData + 'static> UserData for $type {
             fn add_fields<'lua, F: UserDataFields<'lua, Self>>(fields: &mut F) {
-                let mut orig_fields = UserDataRegistrar::new();
+                let mut orig_fields = UserDataRegistry::new();
                 T::add_fields(&mut orig_fields);
                 fields.append_fields_from(orig_fields);
             }
 
             fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
-                let mut orig_methods = UserDataRegistrar::new();
+                let mut orig_methods = UserDataRegistry::new();
                 T::add_methods(&mut orig_methods);
                 methods.append_methods_from(orig_methods);
             }
@@ -659,8 +799,12 @@ macro_rules! lua_userdata_impl {
     };
 }
 
+#[cfg(not(feature = "send"))]
+lua_userdata_impl!(Rc<T>);
 #[cfg(not(feature = "send"))]
 lua_userdata_impl!(Rc<RefCell<T>>);
+
+lua_userdata_impl!(Arc<T>);
 lua_userdata_impl!(Arc<Mutex<T>>);
 lua_userdata_impl!(Arc<RwLock<T>>);
 #[cfg(feature = "parking_lot")]

src/util/mod.rs

@@ -1,11 +1,12 @@
 use std::any::{Any, TypeId};
+use std::borrow::Cow;
 use std::ffi::CStr;
 use std::fmt::Write;
 use std::mem::MaybeUninit;
 use std::os::raw::{c_char, c_int, c_void};
 use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe};
 use std::sync::Arc;
-use std::{mem, ptr, slice};
+use std::{mem, ptr, slice, str};
 
 use once_cell::sync::Lazy;
 use rustc_hash::FxHashMap;
@@ -251,10 +252,12 @@ pub unsafe fn push_string(state: *mut ffi::lua_State, s: &[u8], protect: bool) -
 #[inline]
 pub unsafe fn push_table(
     state: *mut ffi::lua_State,
-    narr: c_int,
-    nrec: c_int,
+    narr: usize,
+    nrec: usize,
     protect: bool,
 ) -> Result<()> {
+    let narr: c_int = narr.try_into().unwrap_or(c_int::MAX);
+    let nrec: c_int = nrec.try_into().unwrap_or(c_int::MAX);
     if protect {
         protect_lua!(state, 0, 1, |state| ffi::lua_createtable(state, narr, nrec))
     } else {
@@ -543,12 +546,13 @@ pub unsafe fn init_userdata_metatable_newindex(state: *mut ffi::lua_State) -> Re
 // captured `__index` if no matches found.
 // The same is also applicable for `__newindex` metamethod and `field_setters` table.
 // Internally uses 9 stack spaces and does not call checkstack.
-pub unsafe fn init_userdata_metatable<T>(
+pub unsafe fn init_userdata_metatable(
     state: *mut ffi::lua_State,
     metatable: c_int,
     field_getters: Option<c_int>,
     field_setters: Option<c_int>,
     methods: Option<c_int>,
+    extra_init: Option<fn(*mut ffi::lua_State) -> Result<()>>,
 ) -> Result<()> {
     ffi::lua_pushvalue(state, metatable);
 
@@ -595,10 +599,9 @@ pub unsafe fn init_userdata_metatable<T>(
         rawset_field(state, -2, "__newindex")?;
     }
 
-    #[cfg(not(feature = "luau"))]
-    {
-        ffi::lua_pushcfunction(state, userdata_destructor::<T>);
-        rawset_field(state, -2, "__gc")?;
+    // Additional initialization
+    if let Some(extra_init) = extra_init {
+        extra_init(state)?;
     }
 
     ffi::lua_pushboolean(state, 0);
@@ -655,8 +658,6 @@ where
         Ok(Err(err)) => {
             ffi::lua_settop(state, 1);
 
-            let wrapped_error = ud as *mut WrappedFailure;
-
             // Build `CallbackError` with traceback
             let traceback = if ffi::lua_checkstack(state, ffi::LUA_TRACEBACK_STACK) != 0 {
                 ffi::luaL_traceback(state, state, ptr::null(), 0);
@@ -667,10 +668,8 @@ where
                 "<not enough stack space for traceback>".to_string()
             };
             let cause = Arc::new(err);
-            ptr::write(
-                wrapped_error,
-                WrappedFailure::Error(Error::CallbackError { traceback, cause }),
-            );
+            let wrapped_error = WrappedFailure::Error(Error::CallbackError { traceback, cause });
+            ptr::write(ud, wrapped_error);
             get_gc_metatable::<WrappedFailure>(state);
             ffi::lua_setmetatable(state, -2);
 
@@ -678,7 +677,7 @@ where
         }
         Err(p) => {
             ffi::lua_settop(state, 1);
-            ptr::write(ud as *mut WrappedFailure, WrappedFailure::Panic(Some(p)));
+            ptr::write(ud, WrappedFailure::Panic(Some(p)));
             get_gc_metatable::<WrappedFailure>(state);
             ffi::lua_setmetatable(state, -2);
             ffi::lua_error(state)
@@ -1044,7 +1043,10 @@ pub(crate) unsafe fn to_string(state: *mut ffi::lua_State, index: c_int) -> Stri
             let v = ffi::lua_tovector(state, index);
             mlua_debug_assert!(!v.is_null(), "vector is null");
             let (x, y, z) = (*v, *v.add(1), *v.add(2));
-            format!("vector({x},{y},{z})")
+            #[cfg(not(feature = "luau-vector4"))]
+            return format!("vector({x}, {y}, {z})");
+            #[cfg(feature = "luau-vector4")]
+            return format!("vector({x}, {y}, {z}, {w})", w = *v.add(3));
         }
         ffi::LUA_TSTRING => {
             let mut size = 0;
@@ -1066,11 +1068,25 @@ pub(crate) unsafe fn get_destructed_userdata_metatable(state: *mut ffi::lua_Stat
     ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, key);
 }
 
-pub(crate) unsafe fn ptr_to_cstr_bytes<'a>(input: *const c_char) -> Option<&'a [u8]> {
+pub(crate) unsafe fn ptr_to_str<'a>(input: *const c_char) -> Option<&'a str> {
     if input.is_null() {
         return None;
     }
-    Some(CStr::from_ptr(input).to_bytes())
+    str::from_utf8(CStr::from_ptr(input).to_bytes()).ok()
+}
+
+pub(crate) unsafe fn ptr_to_lossy_str<'a>(input: *const c_char) -> Option<Cow<'a, str>> {
+    if input.is_null() {
+        return None;
+    }
+    Some(String::from_utf8_lossy(CStr::from_ptr(input).to_bytes()))
+}
+
+pub(crate) fn linenumber_to_usize(n: c_int) -> Option<usize> {
+    match n {
+        n if n < 0 => None,
+        n => Some(n as usize),
+    }
 }
 
 static DESTRUCTED_USERDATA_METATABLE: u8 = 0;

src/util/short_names.rs

@@ -1,5 +1,6 @@
-//! Mostly copied from bevy_utils
-//! https://github.com/bevyengine/bevy/blob/main/crates/bevy_utils/src/short_names.rs
+//! Mostly copied from [bevy_utils]
+//!
+//! [bevy_utils]: https://github.com/bevyengine/bevy/blob/main/crates/bevy_utils/src/short_names.rs
 
 use std::any::type_name;
 

src/value.rs

@@ -44,7 +44,7 @@ pub enum Value<'lua> {
     /// A Luau vector.
     #[cfg(any(feature = "luau", doc))]
     #[cfg_attr(docsrs, doc(cfg(feature = "luau")))]
-    Vector(f32, f32, f32),
+    Vector(crate::types::Vector),
     /// An interned string, managed by Lua.
     ///
     /// Unlike Rust strings, Lua strings may not be valid UTF-8.
@@ -79,7 +79,7 @@ impl<'lua> Value<'lua> {
             Value::Integer(_) => "integer",
             Value::Number(_) => "number",
             #[cfg(feature = "luau")]
-            Value::Vector(_, _, _) => "vector",
+            Value::Vector(_) => "vector",
             Value::String(_) => "string",
             Value::Table(_) => "table",
             Value::Function(_) => "function",
@@ -116,18 +116,14 @@ impl<'lua> Value<'lua> {
     /// Typically this function is used only for hashing and debug information.
     #[inline]
     pub fn to_pointer(&self) -> *const c_void {
-        unsafe {
-            match self {
-                Value::LightUserData(ud) => ud.0,
-                Value::Table(t) => t.to_pointer(),
-                Value::String(s) => s.to_pointer(),
-                Value::Function(Function(r))
-                | Value::Thread(Thread(r))
-                | Value::UserData(AnyUserData(r)) => {
-                    ffi::lua_topointer(r.lua.ref_thread(), r.index)
-                }
-                _ => ptr::null(),
-            }
+        match self {
+            Value::LightUserData(ud) => ud.0,
+            Value::String(String(r))
+            | Value::Table(Table(r))
+            | Value::Function(Function(r))
+            | Value::Thread(Thread(r))
+            | Value::UserData(AnyUserData(r)) => r.to_pointer(),
+            _ => ptr::null(),
         }
     }
 
@@ -143,7 +139,7 @@ impl<'lua> Value<'lua> {
             Value::Integer(i) => Ok(i.to_string()),
             Value::Number(n) => Ok(n.to_string()),
             #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) => Ok(format!("vector({x}, {y}, {z})")),
+            Value::Vector(v) => Ok(v.to_string()),
             Value::String(s) => Ok(s.to_str()?.to_string()),
             Value::Table(Table(r))
             | Value::Function(Function(r))
@@ -218,7 +214,7 @@ impl<'lua> Value<'lua> {
             Value::Integer(i) => write!(fmt, "{i}"),
             Value::Number(n) => write!(fmt, "{n}"),
             #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) => write!(fmt, "vector({x}, {y}, {z})"),
+            Value::Vector(v) => write!(fmt, "{v}"),
             Value::String(s) => write!(fmt, "{s:?}"),
             Value::Table(t) if recursive && !visited.contains(&t.to_pointer()) => {
                 t.fmt_pretty(fmt, ident, visited)
@@ -227,9 +223,13 @@ impl<'lua> Value<'lua> {
             f @ Value::Function(_) => write!(fmt, "function: {:?}", f.to_pointer()),
             t @ Value::Thread(_) => write!(fmt, "thread: {:?}", t.to_pointer()),
             u @ Value::UserData(ud) => {
+                // Try `__name` first then `__tostring`
                 let name = ud.type_name().ok().flatten();
-                let name = name.unwrap_or_else(|| "userdata".to_string());
-                write!(fmt, "{name}: {:?}", u.to_pointer())
+                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::Error(e) if recursive => write!(fmt, "{e:?}"),
             Value::Error(_) => write!(fmt, "error"),
@@ -249,7 +249,7 @@ impl fmt::Debug for Value<'_> {
             Value::Integer(i) => write!(fmt, "Integer({i})"),
             Value::Number(n) => write!(fmt, "Number({n})"),
             #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) => write!(fmt, "Vector({x}, {y}, {z})"),
+            Value::Vector(v) => write!(fmt, "{v:?}"),
             Value::String(s) => write!(fmt, "String({s:?})"),
             Value::Table(t) => write!(fmt, "{t:?}"),
             Value::Function(f) => write!(fmt, "{f:?}"),
@@ -271,7 +271,7 @@ impl<'lua> PartialEq for Value<'lua> {
             (Value::Number(a), Value::Integer(b)) => *a == *b as Number,
             (Value::Number(a), Value::Number(b)) => *a == *b,
             #[cfg(feature = "luau")]
-            (Value::Vector(x1, y1, z1), Value::Vector(x2, y2, z2)) => (x1, y1, z1) == (x2, y2, z2),
+            (Value::Vector(v1), Value::Vector(v2)) => v1 == v2,
             (Value::String(a), Value::String(b)) => a == b,
             (Value::Table(a), Value::Table(b)) => a == b,
             (Value::Function(a), Value::Function(b)) => a == b,
@@ -303,7 +303,7 @@ impl<'lua> Serialize for Value<'lua> {
                 .serialize_i64((*i).try_into().expect("cannot convert Lua Integer to i64")),
             Value::Number(n) => serializer.serialize_f64(*n),
             #[cfg(feature = "luau")]
-            Value::Vector(x, y, z) => (x, y, z).serialize(serializer),
+            Value::Vector(v) => v.serialize(serializer),
             Value::String(s) => s.serialize(serializer),
             Value::Table(t) => t.serialize(serializer),
             Value::UserData(ud) => ud.serialize(serializer),

tests/async.rs

@@ -1,10 +1,8 @@
 #![cfg(feature = "async")]
 
-use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
-use futures_timer::Delay;
 use futures_util::stream::TryStreamExt;
 
 use mlua::{
@@ -12,6 +10,10 @@ use mlua::{
     UserDataMethods, Value,
 };
 
+async fn sleep_ms(ms: u64) {
+    tokio::time::sleep(Duration::from_millis(ms)).await;
+}
+
 #[tokio::test]
 async fn test_async_function() -> Result<()> {
     let lua = Lua::new();
@@ -44,7 +46,7 @@ async fn test_async_sleep() -> Result<()> {
     let lua = Lua::new();
 
     let sleep = lua.create_async_function(move |_lua, n: u64| async move {
-        Delay::new(Duration::from_millis(n)).await;
+        sleep_ms(n).await;
         Ok(format!("elapsed:{}ms", n))
     })?;
     lua.globals().set("sleep", sleep)?;
@@ -60,7 +62,7 @@ async fn test_async_call() -> Result<()> {
     let lua = Lua::new();
 
     let hello = lua.create_async_function(|_lua, name: String| async move {
-        Delay::new(Duration::from_millis(10)).await;
+        sleep_ms(10).await;
         Ok(format!("hello, {}!", name))
     })?;
 
@@ -103,7 +105,7 @@ async fn test_async_handle_yield() -> Result<()> {
     let lua = Lua::new();
 
     let sum = lua.create_async_function(|_lua, (a, b): (i64, i64)| async move {
-        Delay::new(Duration::from_millis(10)).await;
+        sleep_ms(10).await;
         Ok(a + b)
     })?;
 
@@ -161,10 +163,10 @@ async fn test_async_return_async_closure() -> Result<()> {
     let lua = Lua::new();
 
     let f = lua.create_async_function(|lua, a: i64| async move {
-        Delay::new(Duration::from_millis(10)).await;
+        sleep_ms(10).await;
 
         let g = lua.create_async_function(move |_, b: i64| async move {
-            Delay::new(Duration::from_millis(10)).await;
+            sleep_ms(10).await;
             return Ok(a + b);
         })?;
 
@@ -254,7 +256,7 @@ async fn test_async_thread() -> Result<()> {
     let f = lua.create_async_function(move |_lua, ()| {
         let cnt3 = cnt2.clone();
         async move {
-            Delay::new(Duration::from_millis(*cnt3.as_ref())).await;
+            sleep_ms(*cnt3.as_ref()).await;
             Ok("done")
         }
     })?;
@@ -297,40 +299,34 @@ async fn test_async_table() -> Result<()> {
     table.set("val", 10)?;
 
     let get_value = lua.create_async_function(|_, table: Table| async move {
-        Delay::new(Duration::from_millis(10)).await;
+        sleep_ms(10).await;
         table.get::<_, i64>("val")
     })?;
     table.set("get_value", get_value)?;
 
     let set_value = lua.create_async_function(|_, (table, n): (Table, i64)| async move {
-        Delay::new(Duration::from_millis(10)).await;
+        sleep_ms(10).await;
         table.set("val", n)
     })?;
     table.set("set_value", set_value)?;
 
     let sleep = lua.create_async_function(|_, n| async move {
-        Delay::new(Duration::from_millis(n)).await;
+        sleep_ms(n).await;
         Ok(format!("elapsed:{}ms", n))
     })?;
     table.set("sleep", sleep)?;
 
     assert_eq!(
-        table
-            .call_async_method::<_, _, i64>("get_value", ())
-            .await?,
+        table.call_async_method::<_, i64>("get_value", ()).await?,
         10
     );
     table.call_async_method("set_value", 15).await?;
     assert_eq!(
-        table
-            .call_async_method::<_, _, i64>("get_value", ())
-            .await?,
+        table.call_async_method::<_, i64>("get_value", ()).await?,
         15
     );
     assert_eq!(
-        table
-            .call_async_function::<_, _, String>("sleep", 7)
-            .await?,
+        table.call_async_function::<_, String>("sleep", 7).await?,
         "elapsed:7ms"
     );
 
@@ -343,12 +339,12 @@ async fn test_async_thread_pool() -> Result<()> {
     let lua = Lua::new_with(StdLib::ALL_SAFE, options)?;
 
     let error_f = lua.create_async_function(|_, ()| async move {
-        Delay::new(Duration::from_millis(10)).await;
-        Err::<(), _>(Error::RuntimeError("test".to_string()))
+        sleep_ms(10).await;
+        Err::<(), _>(Error::runtime("test"))
     })?;
 
     let sleep = lua.create_async_function(|_, n| async move {
-        Delay::new(Duration::from_millis(n)).await;
+        sleep_ms(n).await;
         Ok(format!("elapsed:{}ms", n))
     })?;
 
@@ -361,31 +357,30 @@ async fn test_async_thread_pool() -> Result<()> {
 
 #[tokio::test]
 async fn test_async_userdata() -> Result<()> {
-    #[derive(Clone)]
-    struct MyUserData(Arc<AtomicU64>);
+    struct MyUserData(u64);
 
     impl UserData for MyUserData {
         fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
             methods.add_async_method("get_value", |_, data, ()| async move {
-                Delay::new(Duration::from_millis(10)).await;
-                Ok(data.0.load(Ordering::Relaxed))
+                sleep_ms(10).await;
+                Ok(data.0)
             });
 
-            methods.add_async_method("set_value", |_, data, n| async move {
-                Delay::new(Duration::from_millis(10)).await;
-                data.0.store(n, Ordering::Relaxed);
+            methods.add_async_method_mut("set_value", |_, data, n| async move {
+                sleep_ms(10).await;
+                data.0 = n;
                 Ok(())
             });
 
             methods.add_async_function("sleep", |_, n| async move {
-                Delay::new(Duration::from_millis(n)).await;
+                sleep_ms(n).await;
                 Ok(format!("elapsed:{}ms", n))
             });
 
             #[cfg(not(any(feature = "lua51", feature = "luau")))]
             methods.add_async_meta_method(mlua::MetaMethod::Call, |_, data, ()| async move {
-                let n = data.0.load(Ordering::Relaxed);
-                Delay::new(Duration::from_millis(n)).await;
+                let n = data.0;
+                sleep_ms(n).await;
                 Ok(format!("elapsed:{}ms", n))
             });
 
@@ -393,25 +388,26 @@ async fn test_async_userdata() -> Result<()> {
             methods.add_async_meta_method(
                 mlua::MetaMethod::Index,
                 |_, data, key: String| async move {
-                    Delay::new(Duration::from_millis(10)).await;
+                    sleep_ms(10).await;
                     match key.as_str() {
-                        "ms" => Ok(Some(data.0.load(Ordering::Relaxed) as f64)),
-                        "s" => Ok(Some((data.0.load(Ordering::Relaxed) as f64) / 1000.0)),
+                        "ms" => Ok(Some(data.0 as f64)),
+                        "s" => Ok(Some((data.0 as f64) / 1000.0)),
                         _ => Ok(None),
                     }
                 },
             );
 
             #[cfg(not(any(feature = "lua51", feature = "luau")))]
-            methods.add_async_meta_method(
+            methods.add_async_meta_method_mut(
                 mlua::MetaMethod::NewIndex,
                 |_, data, (key, value): (String, f64)| async move {
-                    Delay::new(Duration::from_millis(10)).await;
+                    sleep_ms(10).await;
                     match key.as_str() {
-                        "ms" => Ok(data.0.store(value as u64, Ordering::Relaxed)),
-                        "s" => Ok(data.0.store((value * 1000.0) as u64, Ordering::Relaxed)),
-                        _ => Err(Error::external(format!("key '{}' not found", key))),
+                        "ms" => data.0 = value as u64,
+                        "s" => data.0 = (value * 1000.0) as u64,
+                        _ => return Err(Error::external(format!("key '{}' not found", key))),
                     }
+                    Ok(())
                 },
             );
         }
@@ -420,7 +416,7 @@ async fn test_async_userdata() -> Result<()> {
     let lua = Lua::new();
     let globals = lua.globals();
 
-    let userdata = lua.create_userdata(MyUserData(Arc::new(AtomicU64::new(11))))?;
+    let userdata = lua.create_userdata(MyUserData(11))?;
     globals.set("userdata", userdata.clone())?;
 
     lua.load(
@@ -492,7 +488,7 @@ async fn test_owned_async_call() -> Result<()> {
 
     let hello = lua
         .create_async_function(|_, name: String| async move {
-            Delay::new(Duration::from_millis(10)).await;
+            sleep_ms(10).await;
             Ok(format!("hello, {}!", name))
         })?
         .into_owned();
@@ -513,7 +509,7 @@ async fn test_async_terminate() -> Result<()> {
         let mutex = mutex2.clone();
         async move {
             let _guard = mutex.lock();
-            Delay::new(Duration::from_millis(100)).await;
+            sleep_ms(100).await;
             Ok(())
         }
     })?;

tests/compile.rs

@@ -15,7 +15,11 @@ fn test_compilation() {
     t.compile_fail("tests/compile/static_callback_args.rs");
 
     #[cfg(feature = "async")]
-    t.compile_fail("tests/compile/async_nonstatic_userdata.rs");
+    {
+        t.compile_fail("tests/compile/async_any_userdata_method.rs");
+        t.compile_fail("tests/compile/async_nonstatic_userdata.rs");
+        t.compile_fail("tests/compile/async_userdata_method.rs");
+    }
 
     #[cfg(feature = "send")]
     t.compile_fail("tests/compile/non_send.rs");

tests/compile/async_any_userdata_method.rs

@@ -0,0 +1,14 @@
+use mlua::{UserDataMethods, Lua};
+
+fn main() {
+    let lua = Lua::new();
+
+    lua.register_userdata_type::<String>(|reg| {
+        let s = String::new();
+        let mut s = &s;
+        reg.add_async_method("t", |_, this: &String, ()| async {
+            s = this;
+            Ok(())
+        });
+    }).unwrap();
+}

tests/compile/async_any_userdata_method.stderr

@@ -0,0 +1,81 @@
+error: lifetime may not live long enough
+  --> tests/compile/async_any_userdata_method.rs:9:58
+   |
+9  |           reg.add_async_method("t", |_, this: &String, ()| async {
+   |  ___________________________________----------------------_^
+   | |                                   |                    |
+   | |                                   |                    return type of closure `[async block@$DIR/tests/compile/async_any_userdata_method.rs:9:58: 12:10]` contains a lifetime `'2`
+   | |                                   lifetime `'1` represents this closure's body
+10 | |             s = this;
+11 | |             Ok(())
+12 | |         });
+   | |_________^ returning this value requires that `'1` must outlive `'2`
+   |
+   = note: closure implements `Fn`, so references to captured variables can't escape the closure
+
+error[E0596]: cannot borrow `s` as mutable, as it is a captured variable in a `Fn` closure
+  --> tests/compile/async_any_userdata_method.rs:9:58
+   |
+9  |           reg.add_async_method("t", |_, this: &String, ()| async {
+   |  __________________________________________________________^
+10 | |             s = this;
+   | |             - mutable borrow occurs due to use of `s` in closure
+11 | |             Ok(())
+12 | |         });
+   | |_________^ cannot borrow as mutable
+
+error[E0597]: `s` does not live long enough
+  --> tests/compile/async_any_userdata_method.rs:8:21
+   |
+8  |           let mut s = &s;
+   |                       ^^ borrowed value does not live long enough
+9  | /         reg.add_async_method("t", |_, this: &String, ()| async {
+10 | |             s = this;
+11 | |             Ok(())
+12 | |         });
+   | |__________- argument requires that `s` is borrowed for `'static`
+13 |       }).unwrap();
+   |       - `s` dropped here while still borrowed
+
+error[E0521]: borrowed data escapes outside of closure
+  --> tests/compile/async_any_userdata_method.rs:9:9
+   |
+6  |       lua.register_userdata_type::<String>(|reg| {
+   |                                             ---
+   |                                             |
+   |                                             `reg` is a reference that is only valid in the closure body
+   |                                             has type `&mut LuaUserDataRegistry<'1, std::string::String>`
+...
+9  | /         reg.add_async_method("t", |_, this: &String, ()| async {
+10 | |             s = this;
+11 | |             Ok(())
+12 | |         });
+   | |          ^
+   | |          |
+   | |__________`reg` escapes the closure body here
+   |            argument requires that `'1` must outlive `'static`
+   |
+   = note: requirement occurs because of a mutable reference to `LuaUserDataRegistry<'_, std::string::String>`
+   = note: mutable references are invariant over their type parameter
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+
+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: &String, ()| async {
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^ may outlive borrowed value `s`
+10 |             s = this;
+   |             - `s` is borrowed here
+   |
+note: function requires argument type to outlive `'static`
+  --> tests/compile/async_any_userdata_method.rs:9:9
+   |
+9  | /         reg.add_async_method("t", |_, this: &String, ()| 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: &String, ()| async {
+   |                                   ++++

tests/compile/async_nonstatic_userdata.stderr

@@ -4,11 +4,8 @@ error: lifetime may not live long enough
 7  |       impl<'a> UserData for MyUserData<'a> {
    |            -- lifetime `'a` defined here
 8  |           fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
-   |                          ---- lifetime `'lua` defined here
 9  | /             methods.add_async_method("print", |_, data, ()| async move {
 10 | |                 println!("{}", data.0);
 11 | |                 Ok(())
 12 | |             });
-   | |______________^ argument requires that `'a` must outlive `'lua`
-   |
-   = help: consider adding the following bound: `'a: 'lua`
+   | |______________^ requires that `'a` must outlive `'static`

tests/compile/async_userdata_method.rs

@@ -0,0 +1,14 @@
+use mlua::{UserData, UserDataMethods};
+
+struct MyUserData;
+
+impl UserData for MyUserData {
+    fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
+        methods.add_async_method("method", |_, this: &'static Self, ()| async {
+            Ok(())
+        });
+        // ^ lifetime may not live long enough
+    }
+}
+
+fn main() {}

tests/compile/async_userdata_method.stderr

@@ -0,0 +1,17 @@
+warning: unused variable: `this`
+ --> tests/compile/async_userdata_method.rs:7:48
+  |
+7 |         methods.add_async_method("method", |_, this: &'static Self, ()| async {
+  |                                                ^^^^ help: if this is intentional, prefix it with an underscore: `_this`
+  |
+  = note: `#[warn(unused_variables)]` on by default
+
+error: lifetime may not live long enough
+ --> tests/compile/async_userdata_method.rs:7:9
+  |
+6 |       fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
+  |                      ---- lifetime `'lua` defined here
+7 | /         methods.add_async_method("method", |_, this: &'static Self, ()| async {
+8 | |             Ok(())
+9 | |         });
+  | |__________^ argument requires that `'lua` must outlive `'static`

tests/compile/non_send.stderr

@@ -21,5 +21,5 @@ note: required because it's used within this closure
 note: required by a bound in `Lua::create_function`
   --> src/lua.rs
    |
-   |         F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>,
-   |                      ^^^^^^^^^ required by this bound in `Lua::create_function`
+   |         F: Fn(&'lua Lua, A) -> Result<R> + MaybeSend + 'static,
+   |                                            ^^^^^^^^^ required by this bound in `Lua::create_function`

tests/error.rs

@@ -7,7 +7,7 @@ fn test_error_context() -> Result<()> {
     let lua = Lua::new();
 
     let func = lua.create_function(|_, ()| {
-        Err::<(), _>(Error::RuntimeError("runtime error".into())).context("some context")
+        Err::<(), _>(Error::runtime("runtime error")).context("some context")
     })?;
     lua.globals().set("func", func)?;
 

tests/function.rs

@@ -196,37 +196,37 @@ fn test_function_info() -> Result<()> {
     let function1_info = function1.info();
     #[cfg(feature = "luau")]
     assert_eq!(function1_info.name.as_deref(), Some("function1"));
-    assert_eq!(function1_info.source.as_deref(), Some(b"source1".as_ref()));
-    assert_eq!(function1_info.line_defined, 2);
+    assert_eq!(function1_info.source.as_deref(), Some("source1"));
+    assert_eq!(function1_info.line_defined, Some(2));
     #[cfg(not(feature = "luau"))]
-    assert_eq!(function1_info.last_line_defined, 4);
+    assert_eq!(function1_info.last_line_defined, Some(4));
     #[cfg(feature = "luau")]
-    assert_eq!(function1_info.last_line_defined, -1);
-    assert_eq!(function1_info.what.as_deref(), Some("Lua"));
+    assert_eq!(function1_info.last_line_defined, None);
+    assert_eq!(function1_info.what, "Lua");
 
     let function2_info = function2.info();
     assert_eq!(function2_info.name, None);
-    assert_eq!(function2_info.source.as_deref(), Some(b"source1".as_ref()));
-    assert_eq!(function2_info.line_defined, 3);
+    assert_eq!(function2_info.source.as_deref(), Some("source1"));
+    assert_eq!(function2_info.line_defined, Some(3));
     #[cfg(not(feature = "luau"))]
-    assert_eq!(function2_info.last_line_defined, 3);
+    assert_eq!(function2_info.last_line_defined, Some(3));
     #[cfg(feature = "luau")]
-    assert_eq!(function2_info.last_line_defined, -1);
-    assert_eq!(function2_info.what.as_deref(), Some("Lua"));
+    assert_eq!(function2_info.last_line_defined, None);
+    assert_eq!(function2_info.what, "Lua");
 
     let function3_info = function3.info();
     assert_eq!(function3_info.name, None);
-    assert_eq!(function3_info.source.as_deref(), Some(b"=[C]".as_ref()));
-    assert_eq!(function3_info.line_defined, -1);
-    assert_eq!(function3_info.last_line_defined, -1);
-    assert_eq!(function3_info.what.as_deref(), Some("C"));
+    assert_eq!(function3_info.source.as_deref(), Some("=[C]"));
+    assert_eq!(function3_info.line_defined, None);
+    assert_eq!(function3_info.last_line_defined, None);
+    assert_eq!(function3_info.what, "C");
 
     let print_info = globals.get::<_, Function>("print")?.info();
     #[cfg(feature = "luau")]
     assert_eq!(print_info.name.as_deref(), Some("print"));
-    assert_eq!(print_info.source.as_deref(), Some(b"=[C]".as_ref()));
-    assert_eq!(print_info.what.as_deref(), Some("C"));
-    assert_eq!(print_info.line_defined, -1);
+    assert_eq!(print_info.source.as_deref(), Some("=[C]"));
+    assert_eq!(print_info.what, "C");
+    assert_eq!(print_info.line_defined, None);
 
     Ok(())
 }

tests/hooks.rs

@@ -2,7 +2,6 @@
 
 use std::cell::RefCell;
 use std::ops::Deref;
-use std::str;
 use std::sync::atomic::{AtomicI64, Ordering};
 use std::sync::{Arc, Mutex};
 
@@ -29,7 +28,7 @@ fn test_line_counts() -> Result<()> {
         assert_eq!(debug.event(), DebugEvent::Line);
         hook_output.lock().unwrap().push(debug.curr_line());
         Ok(())
-    })?;
+    });
     lua.load(
         r#"
             local x = 2 + 3
@@ -61,11 +60,10 @@ fn test_function_calls() -> Result<()> {
         assert_eq!(debug.event(), DebugEvent::Call);
         let names = debug.names();
         let source = debug.source();
-        let name = names.name.map(|s| str::from_utf8(s).unwrap().to_owned());
-        let what = source.what.map(|s| str::from_utf8(s).unwrap().to_owned());
-        hook_output.lock().unwrap().push((name, what));
+        let name = names.name.map(|s| s.into_owned());
+        hook_output.lock().unwrap().push((name, source.what));
         Ok(())
-    })?;
+    });
 
     lua.load(
         r#"
@@ -80,18 +78,12 @@ fn test_function_calls() -> Result<()> {
     if cfg!(feature = "luajit") && lua.load("jit.version_num").eval::<i64>()? >= 20100 {
         assert_eq!(
             *output,
-            vec![
-                (None, Some("main".to_string())),
-                (Some("len".to_string()), Some("Lua".to_string()))
-            ]
+            vec![(None, "main"), (Some("len".to_string()), "Lua")]
         );
     } else {
         assert_eq!(
             *output,
-            vec![
-                (None, Some("main".to_string())),
-                (Some("len".to_string()), Some("C".to_string()))
-            ]
+            vec![(None, "main"), (Some("len".to_string()), "C")]
         );
     }
 
@@ -103,10 +95,8 @@ fn test_error_within_hook() -> Result<()> {
     let lua = Lua::new();
 
     lua.set_hook(HookTriggers::EVERY_LINE, |_lua, _debug| {
-        Err(Error::RuntimeError(
-            "Something happened in there!".to_string(),
-        ))
-    })?;
+        Err(Error::runtime("Something happened in there!"))
+    });
 
     let err = lua
         .load("x = 1")
@@ -138,12 +128,12 @@ fn test_limit_execution_instructions() -> Result<()> {
         move |_lua, debug| {
             assert_eq!(debug.event(), DebugEvent::Count);
             if max_instructions.fetch_sub(30, Ordering::Relaxed) <= 30 {
-                Err(Error::RuntimeError("time's up".to_string()))
+                Err(Error::runtime("time's up"))
             } else {
                 Ok(())
             }
         },
-    )?;
+    );
 
     lua.globals().set("x", Value::Integer(0))?;
     let _ = lua
@@ -167,11 +157,11 @@ fn test_hook_removal() -> Result<()> {
     lua.set_hook(
         HookTriggers::new().every_nth_instruction(1),
         |_lua, _debug| {
-            Err(Error::RuntimeError(
-                "this hook should've been removed by this time".to_string(),
+            Err(Error::runtime(
+                "this hook should've been removed by this time",
             ))
         },
-    )?;
+    );
 
     assert!(lua.load("local x = 1").exec().is_err());
     lua.remove_hook();
@@ -215,9 +205,10 @@ fn test_hook_swap_within_hook() -> Result<()> {
                             Ok(())
                         },
                     )
-                })
+                });
+                Ok(())
             })
-    })?;
+    });
 
     TL_LUA.with(|tl| {
         let tl = tl.borrow();

tests/luau.rs

@@ -7,7 +7,9 @@ use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::Arc;
 
-use mlua::{Compiler, CoverageInfo, Error, Lua, Result, Table, ThreadStatus, Value, VmState};
+use mlua::{
+    Compiler, CoverageInfo, Error, Lua, Result, Table, ThreadStatus, Value, Vector, VmState,
+};
 
 #[test]
 fn test_version() -> Result<()> {
@@ -50,13 +52,18 @@ fn test_require() -> Result<()> {
     .exec()
 }
 
+#[cfg(not(feature = "luau-vector4"))]
 #[test]
 fn test_vectors() -> Result<()> {
     let lua = Lua::new();
 
-    let v: [f32; 3] = lua.load("vector(1, 2, 3) + vector(3, 2, 1)").eval()?;
+    let v: Vector = lua.load("vector(1, 2, 3) + vector(3, 2, 1)").eval()?;
     assert_eq!(v, [4.0, 4.0, 4.0]);
 
+    // Test conversion into Rust array
+    let v: [f64; 3] = lua.load("vector(1, 2, 3)").eval()?;
+    assert!(v == [1.0, 2.0, 3.0]);
+
     // Test vector methods
     lua.load(
         r#"
@@ -83,6 +90,46 @@ fn test_vectors() -> Result<()> {
     Ok(())
 }
 
+#[cfg(feature = "luau-vector4")]
+#[test]
+fn test_vectors() -> Result<()> {
+    let lua = Lua::new();
+
+    let v: Vector = lua.load("vector(1, 2, 3, 4) + vector(4, 3, 2, 1)").eval()?;
+    assert_eq!(v, [5.0, 5.0, 5.0, 5.0]);
+
+    // Test conversion into Rust array
+    let v: [f64; 4] = lua.load("vector(1, 2, 3, 4)").eval()?;
+    assert!(v == [1.0, 2.0, 3.0, 4.0]);
+
+    // Test vector methods
+    lua.load(
+        r#"
+        local v = vector(1, 2, 3, 4)
+        assert(v.x == 1)
+        assert(v.y == 2)
+        assert(v.z == 3)
+        assert(v.w == 4)
+    "#,
+    )
+    .exec()?;
+
+    // Test vector methods (fastcall)
+    lua.load(
+        r#"
+        local v = vector(1, 2, 3, 4)
+        assert(v.x == 1)
+        assert(v.y == 2)
+        assert(v.z == 3)
+        assert(v.w == 4)
+    "#,
+    )
+    .set_compiler(Compiler::new().set_vector_ctor(Some("vector".to_string())))
+    .exec()?;
+
+    Ok(())
+}
+
 #[test]
 fn test_readonly_table() -> Result<()> {
     let lua = Lua::new();
@@ -232,7 +279,7 @@ fn test_interrupts() -> Result<()> {
     //
     // Test errors in interrupts
     //
-    lua.set_interrupt(|_| Err(Error::RuntimeError("error from interrupt".into())));
+    lua.set_interrupt(|_| Err(Error::runtime("error from interrupt")));
     match f.call::<_, ()>(()) {
         Err(Error::CallbackError { cause, .. }) => match *cause {
             Error::RuntimeError(ref m) if m == "error from interrupt" => {}
@@ -254,8 +301,8 @@ fn test_coverage() -> Result<()> {
 
     let f = lua
         .load(
-            r#"local v = vector(1, 2, 3)
-        assert(v.x == 1 and v.y == 2 and v.z == 3)
+            r#"local s = "abc"
+        assert(#s == 3)
 
         function abc(i)
             if i < 5 then

tests/module/src/lib.rs

@@ -26,7 +26,7 @@ struct MyUserData(i32);
 
 impl LuaUserData for MyUserData {}
 
-#[mlua::lua_module(name = "test_module_second")]
+#[mlua::lua_module(name = "test_module_second", skip_memory_check)]
 fn test_module2(lua: &Lua) -> LuaResult<LuaTable> {
     let exports = lua.create_table()?;
     exports.set("userdata", MyUserData(123))?;

tests/serde.rs

@@ -145,7 +145,7 @@ fn test_serialize_failure() -> Result<(), Box<dyn StdError>> {
     Ok(())
 }
 
-#[cfg(feature = "luau")]
+#[cfg(all(feature = "luau", not(feature = "luau-vector4")))]
 #[test]
 fn test_serialize_vector() -> Result<(), Box<dyn StdError>> {
     let lua = Lua::new();
@@ -153,7 +153,7 @@ fn test_serialize_vector() -> Result<(), Box<dyn StdError>> {
     let globals = lua.globals();
     globals.set(
         "vector",
-        lua.create_function(|_, (x, y, z)| Ok(Value::Vector(x, y, z)))?,
+        lua.create_function(|_, (x, y, z)| Ok(mlua::Vector::new(x, y, z)))?,
     )?;
 
     let val = lua.load("{_vector = vector(1, 2, 3)}").eval::<Value>()?;
@@ -168,6 +168,29 @@ fn test_serialize_vector() -> Result<(), Box<dyn StdError>> {
     Ok(())
 }
 
+#[cfg(feature = "luau-vector4")]
+#[test]
+fn test_serialize_vector() -> Result<(), Box<dyn StdError>> {
+    let lua = Lua::new();
+
+    let globals = lua.globals();
+    globals.set(
+        "vector",
+        lua.create_function(|_, (x, y, z, w)| Ok(mlua::Vector::new(x, y, z, w)))?,
+    )?;
+
+    let val = lua.load("{_vector = vector(1, 2, 3, 4)}").eval::<Value>()?;
+    let json = serde_json::json!({
+        "_vector": [1.0, 2.0, 3.0, 4.0],
+    });
+    assert_eq!(serde_json::to_value(&val)?, json);
+
+    let expected_json = lua.from_value::<serde_json::Value>(val)?;
+    assert_eq!(expected_json, json);
+
+    Ok(())
+}
+
 #[test]
 fn test_to_value_struct() -> LuaResult<()> {
     let lua = Lua::new();

tests/table.rs

@@ -1,7 +1,7 @@
 use mlua::{Error, Lua, Nil, Result, Table, TableExt, Value};
 
 #[test]
-fn test_set_get() -> Result<()> {
+fn test_globals_set_get() -> Result<()> {
     let lua = Lua::new();
 
     let globals = lua.globals();
@@ -43,6 +43,7 @@ fn test_table() -> Result<()> {
     let table3 = globals.get::<_, Table>("table3")?;
 
     assert_eq!(table1.len()?, 5);
+    assert!(!table1.is_empty());
     assert_eq!(
         table1
             .clone()
@@ -57,8 +58,10 @@ fn test_table() -> Result<()> {
             .collect::<Result<Vec<i64>>>()?,
         vec![1, 2, 3, 4, 5]
     );
+    assert_eq!(table1, [1, 2, 3, 4, 5]);
 
     assert_eq!(table2.len()?, 0);
+    assert!(table2.is_empty());
     assert_eq!(
         table2
             .clone()
@@ -66,12 +69,10 @@ fn test_table() -> Result<()> {
             .collect::<Result<Vec<(i64, i64)>>>()?,
         vec![]
     );
-    assert_eq!(
-        table2.sequence_values().collect::<Result<Vec<i64>>>()?,
-        vec![]
-    );
+    assert_eq!(table2, [0; 0]);
 
     // sequence_values should only iterate until the first border
+    assert_eq!(table3, [1, 2]);
     assert_eq!(
         table3.sequence_values().collect::<Result<Vec<i64>>>()?,
         vec![1, 2]
@@ -116,17 +117,12 @@ fn test_table_push_pop() -> Result<()> {
     // Test raw access
     let table1 = lua.create_sequence_from(vec![123])?;
     table1.raw_push(321)?;
-    assert_eq!(
-        table1
-            .clone()
-            .raw_sequence_values::<i64>()
-            .collect::<Result<Vec<_>>>()?,
-        vec![123, 321]
-    );
+    assert_eq!(table1, [123, 321]);
     assert_eq!(table1.raw_pop::<i64>()?, 321);
     assert_eq!(table1.raw_pop::<i64>()?, 123);
     assert_eq!(table1.raw_pop::<Value>()?, Value::Nil); // An extra pop should do nothing
     assert_eq!(table1.raw_len(), 0);
+    assert_eq!(table1, [0; 0]);
 
     // Test access through metamethods
     let table2 = lua
@@ -144,6 +140,13 @@ fn test_table_push_pop() -> Result<()> {
         .eval::<Table>()?;
     table2.push(345)?;
     assert_eq!(table2.len()?, 2);
+    assert_eq!(
+        table2
+            .clone()
+            .sequence_values::<i64>()
+            .collect::<Result<Vec<_>>>()?,
+        vec![]
+    );
     assert_eq!(table2.pop::<i64>()?, 345);
     assert_eq!(table2.pop::<i64>()?, 234);
     assert_eq!(table2.pop::<Value>()?, Value::Nil);
@@ -191,8 +194,10 @@ fn test_table_clear() -> Result<()> {
         )
         .eval::<Table>()?;
     assert_eq!(t2.raw_len(), 3);
+    assert!(!t2.is_empty());
     t2.clear()?;
     assert_eq!(t2.raw_len(), 0);
+    assert!(t2.is_empty());
     assert_eq!(t2.raw_get::<_, Value>("a")?, Value::Nil);
     assert_ne!(t2.get_metatable(), None);
 
@@ -205,29 +210,9 @@ fn test_table_sequence_from() -> Result<()> {
 
     let get_table = lua.create_function(|_, t: Table| Ok(t))?;
 
-    assert_eq!(
-        get_table
-            .call::<_, Table>(vec![1, 2, 3])?
-            .sequence_values()
-            .collect::<Result<Vec<i64>>>()?,
-        vec![1, 2, 3]
-    );
-
-    assert_eq!(
-        get_table
-            .call::<_, Table>([1, 2, 3].as_ref())?
-            .sequence_values()
-            .collect::<Result<Vec<i64>>>()?,
-        vec![1, 2, 3]
-    );
-
-    assert_eq!(
-        get_table
-            .call::<_, Table>([1, 2, 3])?
-            .sequence_values()
-            .collect::<Result<Vec<i64>>>()?,
-        vec![1, 2, 3]
-    );
+    assert_eq!(get_table.call::<_, Table>(vec![1, 2, 3])?, [1, 2, 3]);
+    assert_eq!(get_table.call::<_, Table>([4, 5, 6])?, [4, 5, 6]);
+    assert_eq!(get_table.call::<_, Table>([7, 8, 9].as_slice())?, [7, 8, 9]);
 
     Ok(())
 }
@@ -377,11 +362,8 @@ fn test_table_call() -> Result<()> {
     let table: Table = lua.globals().get("table")?;
 
     assert_eq!(table.call::<_, String>("b")?, "call_2");
-    assert_eq!(table.call_function::<_, _, String>("func", "a")?, "func_a");
-    assert_eq!(
-        table.call_method::<_, _, String>("method", "a")?,
-        "method_1"
-    );
+    assert_eq!(table.call_function::<_, String>("func", "a")?, "func_a");
+    assert_eq!(table.call_method::<_, String>("method", "a")?, "method_1");
 
     // Test calling non-callable table
     let table2 = lua.create_table()?;

tests/tests.rs

@@ -1226,8 +1226,8 @@ fn test_inspect_stack() -> Result<()> {
 
     let logline = lua.create_function(|lua, msg: StdString| {
         let debug = lua.inspect_stack(1).unwrap(); // caller
-        let source = debug.source().short_src.map(core::str::from_utf8);
-        let source = source.transpose().unwrap().unwrap_or("?");
+        let source = debug.source().short_src;
+        let source = source.as_deref().unwrap_or("?");
         let line = debug.curr_line();
         Ok(format!("{}:{} {}", source, line, msg))
     })?;
@@ -1278,20 +1278,20 @@ fn test_warnings() -> Result<()> {
     let lua = Lua::new();
     lua.set_app_data::<Vec<(StdString, bool)>>(Vec::new());
 
-    lua.set_warning_function(|lua, msg, tocont| {
-        let msg = msg.to_string_lossy().to_string();
+    lua.set_warning_function(|lua, msg, incomplete| {
         lua.app_data_mut::<Vec<(StdString, bool)>>()
             .unwrap()
-            .push((msg, tocont));
+            .push((msg.to_string(), incomplete));
         Ok(())
     });
 
-    lua.warning("native warning ...", true)?;
-    lua.warning("finish", false)?;
+    lua.warning("native warning ...", true);
+    lua.warning("finish", false);
+    lua.warning("\0", false);
     lua.load(r#"warn("lua warning", "continue")"#).exec()?;
 
     lua.remove_warning_function();
-    lua.warning("one more warning", false)?;
+    lua.warning("one more warning", false);
 
     let messages = lua.app_data_ref::<Vec<(StdString, bool)>>().unwrap();
     assert_eq!(
@@ -1299,13 +1299,14 @@ fn test_warnings() -> Result<()> {
         vec![
             ("native warning ...".to_string(), true),
             ("finish".to_string(), false),
+            ("".to_string(), false),
             ("lua warning".to_string(), true),
             ("continue".to_string(), false),
         ]
     );
 
     // Trigger error inside warning
-    lua.set_warning_function(|_, _, _| Err(Error::RuntimeError("warning error".to_string())));
+    lua.set_warning_function(|_, _, _| Err(Error::runtime("warning error")));
     assert!(matches!(
         lua.load(r#"warn("test")"#).exec(),
         Err(Error::CallbackError { cause, .. })

tests/userdata.rs

@@ -411,21 +411,21 @@ fn test_user_values() -> Result<()> {
     ud.set_nth_user_value(1, "hello")?;
     ud.set_nth_user_value(2, "world")?;
     ud.set_nth_user_value(65535, 321)?;
-    assert_eq!(ud.get_nth_user_value::<String>(1)?, "hello");
-    assert_eq!(ud.get_nth_user_value::<String>(2)?, "world");
-    assert_eq!(ud.get_nth_user_value::<Value>(3)?, Value::Nil);
-    assert_eq!(ud.get_nth_user_value::<i32>(65535)?, 321);
+    assert_eq!(ud.nth_user_value::<String>(1)?, "hello");
+    assert_eq!(ud.nth_user_value::<String>(2)?, "world");
+    assert_eq!(ud.nth_user_value::<Value>(3)?, Value::Nil);
+    assert_eq!(ud.nth_user_value::<i32>(65535)?, 321);
 
-    assert!(ud.get_nth_user_value::<Value>(0).is_err());
-    assert!(ud.get_nth_user_value::<Value>(65536).is_err());
+    assert!(ud.nth_user_value::<Value>(0).is_err());
+    assert!(ud.nth_user_value::<Value>(65536).is_err());
 
     // Named user values
     ud.set_named_user_value("name", "alex")?;
     ud.set_named_user_value("age", 10)?;
 
-    assert_eq!(ud.get_named_user_value::<String>("name")?, "alex");
-    assert_eq!(ud.get_named_user_value::<i32>("age")?, 10);
-    assert_eq!(ud.get_named_user_value::<Value>("nonexist")?, Value::Nil);
+    assert_eq!(ud.named_user_value::<String>("name")?, "alex");
+    assert_eq!(ud.named_user_value::<i32>("age")?, 10);
+    assert_eq!(ud.named_user_value::<Value>("nonexist")?, Value::Nil);
 
     Ok(())
 }
@@ -495,7 +495,7 @@ fn test_fields() -> Result<()> {
             });
 
             // Use userdata "uservalue" storage
-            fields.add_field_function_get("uval", |_, ud| ud.get_user_value::<Option<String>>());
+            fields.add_field_function_get("uval", |_, ud| ud.user_value::<Option<String>>());
             fields
                 .add_field_function_set("uval", |_, ud, s| ud.set_user_value::<Option<String>>(s));
 
@@ -625,10 +625,33 @@ fn test_userdata_wrapped() -> Result<()> {
     let lua = Lua::new();
     let globals = lua.globals();
 
+    // Rc<T>
     #[cfg(not(feature = "send"))]
     {
-        let ud1 = Rc::new(RefCell::new(MyUserData(1)));
-        globals.set("rc_refcell_ud", ud1.clone())?;
+        let ud = Rc::new(MyUserData(1));
+        globals.set("rc_ud", ud.clone())?;
+        lua.load(
+            r#"
+            assert(rc_ud.static == "constant")
+            local ok, err = pcall(function() rc_ud.data = 2 end)
+            assert(
+                tostring(err):sub(1, 32) == "error mutably borrowing userdata",
+                "expected error mutably borrowing userdata, got " .. tostring(err)
+            )
+            assert(rc_ud.data == 1)
+        "#,
+        )
+        .exec()?;
+        globals.set("rc_ud", Nil)?;
+        lua.gc_collect()?;
+        assert_eq!(Rc::strong_count(&ud), 1);
+    }
+
+    // Rc<RefCell<T>>
+    #[cfg(not(feature = "send"))]
+    {
+        let ud = Rc::new(RefCell::new(MyUserData(1)));
+        globals.set("rc_refcell_ud", ud.clone())?;
         lua.load(
             r#"
             assert(rc_refcell_ud.static == "constant")
@@ -637,12 +660,32 @@ fn test_userdata_wrapped() -> Result<()> {
         "#,
         )
         .exec()?;
-        assert_eq!(ud1.borrow().0, 2);
+        assert_eq!(ud.borrow().0, 2);
         globals.set("rc_refcell_ud", Nil)?;
         lua.gc_collect()?;
-        assert_eq!(Rc::strong_count(&ud1), 1);
+        assert_eq!(Rc::strong_count(&ud), 1);
     }
 
+    // Arc<T>
+    let ud1 = Arc::new(MyUserData(2));
+    globals.set("arc_ud", ud1.clone())?;
+    lua.load(
+        r#"
+        assert(arc_ud.static == "constant")
+        local ok, err = pcall(function() arc_ud.data = 3 end)
+        assert(
+            tostring(err):sub(1, 32) == "error mutably borrowing userdata",
+            "expected error mutably borrowing userdata, got " .. tostring(err)
+        )
+        assert(arc_ud.data == 2)
+    "#,
+    )
+    .exec()?;
+    globals.set("arc_ud", Nil)?;
+    lua.gc_collect()?;
+    assert_eq!(Arc::strong_count(&ud1), 1);
+
+    // Arc<Mutex<T>>
     let ud2 = Arc::new(Mutex::new(MyUserData(2)));
     globals.set("arc_mutex_ud", ud2.clone())?;
     lua.load(
@@ -657,7 +700,11 @@ fn test_userdata_wrapped() -> Result<()> {
     assert_eq!(ud2.lock().unwrap().0, 3);
     #[cfg(feature = "parking_lot")]
     assert_eq!(ud2.lock().0, 3);
+    globals.set("arc_mutex_ud", Nil)?;
+    lua.gc_collect()?;
+    assert_eq!(Arc::strong_count(&ud2), 1);
 
+    // Arc<RwLock<T>>
     let ud3 = Arc::new(RwLock::new(MyUserData(3)));
     globals.set("arc_rwlock_ud", ud3.clone())?;
     lua.load(
@@ -672,12 +719,8 @@ fn test_userdata_wrapped() -> Result<()> {
     assert_eq!(ud3.read().unwrap().0, 4);
     #[cfg(feature = "parking_lot")]
     assert_eq!(ud3.read().0, 4);
-
-    // Test drop
-    globals.set("arc_mutex_ud", Nil)?;
     globals.set("arc_rwlock_ud", Nil)?;
     lua.gc_collect()?;
-    assert_eq!(Arc::strong_count(&ud2), 1);
     assert_eq!(Arc::strong_count(&ud3), 1);
 
     Ok(())
@@ -753,6 +796,27 @@ fn test_any_userdata() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_any_userdata_wrap() -> Result<()> {
+    let lua = Lua::new();
+
+    lua.register_userdata_type::<StdString>(|reg| {
+        reg.add_method("get", |_, this, ()| Ok(this.clone()));
+    })?;
+
+    lua.globals()
+        .set("s", AnyUserData::wrap("hello".to_string()))?;
+    lua.load(
+        r#"
+        assert(s:get() == "hello")
+    "#,
+    )
+    .exec()
+    .unwrap();
+
+    Ok(())
+}
+
 #[test]
 fn test_userdata_ext() -> Result<()> {
     let lua = Lua::new();

tests/value.rs

@@ -101,11 +101,16 @@ fn test_value_to_string() -> Result<()> {
     );
     assert_eq!(Value::Integer(1).to_string()?, "1");
     assert_eq!(Value::Number(34.59).to_string()?, "34.59");
-    #[cfg(feature = "luau")]
+    #[cfg(all(feature = "luau", not(feature = "luau-vector4")))]
     assert_eq!(
-        Value::Vector(10.0, 11.1, 12.2).to_string()?,
+        Value::Vector(mlua::Vector::new(10.0, 11.1, 12.2)).to_string()?,
         "vector(10, 11.1, 12.2)"
     );
+    #[cfg(feature = "luau-vector4")]
+    assert_eq!(
+        Value::Vector(mlua::Vector::new(10.0, 11.1, 12.2, 13.3)).to_string()?,
+        "vector(10, 11.1, 12.2, 13.3)"
+    );
     assert_eq!(
         Value::String(lua.create_string("hello")?).to_string()?,
         "hello"
@@ -135,7 +140,7 @@ fn test_value_to_string() -> Result<()> {
     let ud: Value = Value::UserData(lua.create_userdata(MyUserData)?);
     assert!(ud.to_string()?.starts_with("MyUserData:"));
 
-    let err = Value::Error(Error::RuntimeError("test error".to_string()));
+    let err = Value::Error(Error::runtime("test error"));
     assert_eq!(err.to_string()?, "runtime error: test error");
 
     Ok(())