NEWS.md: update for recent changes

Add entries for language changes (case/in NoMatchingPatternError, compound statement in tLPAREN_ARG), C API additions (mrb_bigint_p(), RVALUE union), compiler optimizations (literal chunking), build fixes (MSYS2), security fixes, and 26 merged pull requests. Co-authored-by: Claude <noreply@anthropic.com>
Merge pull request #6767 from mruby/fix/lparen-arg-compstmt
2026-06-08 16:11:16 +00:00 · 2026-04-02 20:17:19 +09:00 · 2026-03-30 07:54:31 +09:00 · 2026-03-30 07:06:30 +09:00 · 2026-03-29 22:55:13 +09:00 · 2026-03-28 23:14:46 +01:00
32 changed files with 2940 additions and 2716 deletions
@@ -32,6 +32,8 @@ jobs:
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Compiler version
@@ -45,6 +47,8 @@ jobs:
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Cache cosmocc
@@ -71,6 +75,8 @@ jobs:
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Build and test
@@ -19,6 +19,8 @@ jobs:
    steps:
      - name: Checkout repository
        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
      - name: Initialize CodeQL
        uses: github/codeql-action/init@v4
        with:
@@ -2,6 +2,9 @@ name: Coverage

 on: [push]

+permissions:
+  contents: read
+
 jobs:
  coverage:
    name: Coverage
@@ -17,6 +20,8 @@ jobs:
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Compiler version
@@ -12,6 +12,8 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
      - uses: ls-lint/action@v2.3.1
        with:
          config: .github/linters/.ls-lint.yml
@@ -13,7 +13,9 @@ jobs:
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
        uses: actions/checkout@v6
-      - uses: j178/prek-action@v1
+        with:
+          persist-credentials: false
+      - uses: j178/prek-action@v2
        with:
          install-only: true
      - name: Run manual pre-commit hooks
@@ -13,6 +13,8 @@ jobs:
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
        uses: actions/checkout@v6
-      - uses: j178/prek-action@v1
+        with:
+          persist-credentials: false
+      - uses: j178/prek-action@v2
        with:
          extra-args: --all-files
@@ -20,6 +20,8 @@ jobs:
    steps:
      - name: "Checkout ${{ github.ref_name }} ( ${{ github.sha }} )"
        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
      - name: Builds
        id: builds
        run: |
@@ -19,6 +19,7 @@ jobs:
        with:
          # Full git history is needed to get a proper list of changed files within `super-linter`
          fetch-depth: 0
+          persist-credentials: false
      - name: Lint Code Base
        uses: super-linter/super-linter/slim@v8.5.0
        env:
@@ -3,7 +3,7 @@
 default_stages: [pre-commit, pre-push]
 default_language_version:
  python: python3
-  node: 24.11.1
+  node: 24.14.0
 minimum_pre_commit_version: "3.2.0"
 exclude: "^tools/lrama/"
 repos:
@@ -35,13 +35,13 @@ repos:
          track and have security implications. Please remove the zip file from the repository.
        files: \.zip$
  - repo: https://github.com/gitleaks/gitleaks
-    rev: v8.30.0
+    rev: v8.30.1
    hooks:
      - id: gitleaks
        name: run gitleaks
        description: detect hardcoded secrets with gitleaks
  - repo: https://github.com/oxipng/oxipng
-    rev: v10.0.0
+    rev: v10.1.0
    hooks:
      - id: oxipng
        name: run oxipng
@@ -73,7 +73,7 @@ repos:
      - id: mixed-line-ending
      - id: trailing-whitespace
  - repo: https://github.com/Lucas-C/pre-commit-hooks
-    rev: v1.5.5
+    rev: v1.5.6
    hooks:
      - id: forbid-tabs
        name: run no-tabs checker
@@ -85,19 +85,19 @@ repos:
        args: [--whitespaces-count, "2"]
        exclude: Makefile$
  - repo: https://github.com/rhysd/actionlint
-    rev: v1.7.9
+    rev: v1.7.11
    hooks:
      - id: actionlint
        name: run actionlint
        description: lint GitHub Actions workflow files
  - repo: https://github.com/codespell-project/codespell
-    rev: v2.4.1
+    rev: v2.4.2
    hooks:
      - id: codespell
        name: run codespell
        description: check spelling with codespell
  - repo: https://github.com/igorshubovych/markdownlint-cli
-    rev: v0.46.0
+    rev: v0.48.0
    hooks:
      - id: markdownlint
        name: run markdownlint
@@ -106,7 +106,7 @@ repos:
        types: [markdown]
        files: \.md$
  - repo: https://github.com/rubocop/rubocop
-    rev: v1.81.7
+    rev: v1.86.0
    hooks:
      - id: rubocop
        name: run rubocop
@@ -120,7 +120,7 @@ repos:
        name: run shellcheck
        description: check shell scripts with a static analysis tool
  - repo: https://github.com/adrienverge/yamllint
-    rev: v1.37.1
+    rev: v1.38.0
    hooks:
      - id: yamllint
        name: run yamllint
@@ -23,6 +23,8 @@ mruby now supports pattern matching (case/in) syntax:
 - Trailing comma in method definition parameters: `def foo(a, b,)` ([f78334b](https://github.com/mruby/mruby/commit/f78334b))
 - Array/Hash/String subclasses can now override `[]` and `[]=` methods ([#6675](https://github.com/mruby/mruby/pull/6675))
 - `OP_SETIDX` optimization for Array and Hash ([ddd8fe1](https://github.com/mruby/mruby/commit/ddd8fe1))
+- `case`/`in` without `else` now raises `NoMatchingPatternError` ([d8de35b](https://github.com/mruby/mruby/commit/d8de35b))
+- Allow compound statement in parenthesized argument context ([919cbd8](https://github.com/mruby/mruby/commit/919cbd8))

 # Changes in C API

@@ -37,6 +39,8 @@ mruby now supports pattern matching (case/in) syntax:
 - `mrb_open()` returns mrb_state with exc set on init failure ([05ffe0c](https://github.com/mruby/mruby/commit/05ffe0c))
 - `mrb_utf8_to_buf()` for UTF-8 encoding consolidation ([7e28e68](https://github.com/mruby/mruby/commit/7e28e68))
 - `kh_is_end()` macro for safe khash iteration ([893cc75](https://github.com/mruby/mruby/commit/893cc75))
+- `mrb_bigint_p()` always defined regardless of bigint gem presence ([6c4a8c0](https://github.com/mruby/mruby/commit/6c4a8c0))
+- `RInteger` and `RFloat` added to `RVALUE` union ([13dbca0](https://github.com/mruby/mruby/commit/13dbca0))

 # ROM Method Tables

@@ -76,6 +80,7 @@ mruby-symbol-ext, mruby-range-ext, mruby-object-ext.
 - Emscripten: use native WASM exception handling ([ca364e3](https://github.com/mruby/mruby/commit/ca364e3))
 - HAL (Hardware Abstraction Layer) for platform abstraction in mruby-io, mruby-socket, mruby-dir, mruby-task ([74ca22f](https://github.com/mruby/mruby/commit/74ca22f))
 - `MRUBY_MIRB_READLINE` environment variable to control readline library selection ([0aafb83](https://github.com/mruby/mruby/commit/0aafb83))
+- MSYS2 drive letter support in build script ([77f6ffe](https://github.com/mruby/mruby/commit/77f6ffe))
 - Inter-gem headers separated from external API headers ([#6671](https://github.com/mruby/mruby/pull/6671))

 # Changes in mrbgems
@@ -110,6 +115,7 @@ mruby-symbol-ext, mruby-range-ext, mruby-object-ext.
 ## Other Gem Changes

 - **_NOTE_**: `Hash#deconstruct_keys` removed for CRuby compatibility ([34b9412](https://github.com/mruby/mruby/commit/34b9412))
+- **mruby-enum-lazy**: Fix `Lazy#flat_map` to handle non-enumerable block return values ([#6765](https://github.com/mruby/mruby/pull/6765))
 - **mruby-array-ext**: Add `Array#find` and `Array#rfind` methods
 - **mruby-io**: Add `IO#putc` and `Kernel#putc` ([baff6e6](https://github.com/mruby/mruby/commit/baff6e6))
 - **mruby-random**: Replace xoshiro with PCG for better memory efficiency ([f1bab01](https://github.com/mruby/mruby/commit/f1bab01))
@@ -125,6 +131,8 @@ mruby-symbol-ext, mruby-range-ext, mruby-object-ext.
 - Optimized masgn to generate literals directly into target registers ([fb5d966](https://github.com/mruby/mruby/commit/fb5d966))
 - Optimized splat of literal arrays in args/literals ([1cb8d73](https://github.com/mruby/mruby/commit/1cb8d73))
 - Early termination after too many parse errors ([510ebd7](https://github.com/mruby/mruby/commit/510ebd7))
+- Chunk array literals at 64 elements to reduce register pressure ([f98d641](https://github.com/mruby/mruby/commit/f98d641))
+- Chunk `%w()` and `%i()` literals to reduce register pressure ([62cf0dc](https://github.com/mruby/mruby/commit/62cf0dc))

 # VM Optimizations

@@ -185,6 +193,10 @@ Other optimizations:
 - [#6705](https://github.com/mruby/mruby/issues/6705) Can't get outer class of an object in C
 - [#6713](https://github.com/mruby/mruby/issues/6713) mruby-polarssl not work
 - [#6720](https://github.com/mruby/mruby/issues/6720) Random float range: different behavior from CRuby
+- [#6722](https://github.com/mruby/mruby/issues/6722) RBreak size overflow on 32-bit platforms with MRB_NO_BOXING
+- [#6740](https://github.com/mruby/mruby/issues/6740) `%w()`/`%i()` register pressure with large literals
+- [#6741](https://github.com/mruby/mruby/issues/6741) `case`/`in` without `else` should raise `NoMatchingPatternError`
+- [#6760](https://github.com/mruby/mruby/issues/6760) `mrb_gc_unregister()` not removing all matching entries

 # Merged Pull Requests

@@ -260,6 +272,7 @@ Other optimizations:
 - [#6589](https://github.com/mruby/mruby/pull/6589) Add pre-commit hook `check-zip-file-is-not-committed`
 - [#6591](https://github.com/mruby/mruby/pull/6591) mruby-eval fix license link in README
 - [#6593](https://github.com/mruby/mruby/pull/6593) README: Add Contributors Avatars, Star History, Table of Contents
+- [#6598](https://github.com/mruby/mruby/pull/6598) Fix heap buffer overflow in `#method_missing`
 - [#6599](https://github.com/mruby/mruby/pull/6599) pre-commit: run `markdown-link-check`, `oxipng`, `prettier` manually
 - [#6600](https://github.com/mruby/mruby/pull/6600) `dreamcast_shelf build config`: update to use KallistiOS wrappers
 - [#6601](https://github.com/mruby/mruby/pull/6601) fix: skip local build_config.rb when working in MRUBY_ROOT
@@ -303,6 +316,30 @@ Other optimizations:
 - [#6716](https://github.com/mruby/mruby/pull/6716) Fixes identity for proc object
 - [#6717](https://github.com/mruby/mruby/pull/6717) Fix mruby-task: wrapping by critical section and setting initial task receiver
 - [#6718](https://github.com/mruby/mruby/pull/6718) Add installation instructions for conda and Homebrew
+- [#6723](https://github.com/mruby/mruby/pull/6723) Add `RInteger` and `RFloat` to `RVALUE`
+- [#6727](https://github.com/mruby/mruby/pull/6727) Language documentation: update wording of "overloading" section
+- [#6729](https://github.com/mruby/mruby/pull/6729) Simplifying dependency addition for gensym task
+- [#6730](https://github.com/mruby/mruby/pull/6730) Simplifying presym file generation actions
+- [#6733](https://github.com/mruby/mruby/pull/6733) Include `mruby/presym.h` for all source files
+- [#6734](https://github.com/mruby/mruby/pull/6734) Chunk array literals at 64 elements to reduce register pressure
+- [#6735](https://github.com/mruby/mruby/pull/6735) Prevent full recompilation without changes to presym file
+- [#6739](https://github.com/mruby/mruby/pull/6739) Fix MSYS2 build error with drive letters
+- [#6743](https://github.com/mruby/mruby/pull/6743) Chunk `%w()` and `%i()` literals to reduce register pressure
+- [#6744](https://github.com/mruby/mruby/pull/6744) Raise `NoMatchingPatternError` in `case`/`in` without `else`
+- [#6747](https://github.com/mruby/mruby/pull/6747) Correctly handle empty hash as default named argument
+- [#6749](https://github.com/mruby/mruby/pull/6749) Fix microcontroller profile
+- [#6750](https://github.com/mruby/mruby/pull/6750) Fix out-of-bounds read and divide-by-zero in `Array#product`
+- [#6752](https://github.com/mruby/mruby/pull/6752) Fix `attr_reader`-generated methods accepting extra arguments
+- [#6753](https://github.com/mruby/mruby/pull/6753) Further optimize `Array#product`
+- [#6754](https://github.com/mruby/mruby/pull/6754) Mark `attr_reader` procs as noarg
+- [#6755](https://github.com/mruby/mruby/pull/6755) Reload `ci` after `mrb_hash_delete_key()` in keyword argument handling
+- [#6756](https://github.com/mruby/mruby/pull/6756) Avoid impact of object modifications caused by `mrb_vm_exec()` calls
+- [#6758](https://github.com/mruby/mruby/pull/6758) Don't assign result of `mrb_funcall()` directly to `regs`
+- [#6759](https://github.com/mruby/mruby/pull/6759) Define `mrb_bigint_p()` always
+- [#6761](https://github.com/mruby/mruby/pull/6761) Fix `mrb_gc_unregister()` to remove all matching entries
+- [#6762](https://github.com/mruby/mruby/pull/6762) Write generated test C files atomically to avoid build race condition
+- [#6765](https://github.com/mruby/mruby/pull/6765) Fix `Lazy#flat_map` to handle non-enumerable block return values
+- [#6767](https://github.com/mruby/mruby/pull/6767) Allow compound statement in parenthesized argument context

 # Security Fixes

@@ -320,4 +357,6 @@ Other optimizations:
 - Heap-use-after-free in insertion_sort ([099d2c47](https://github.com/mruby/mruby/commit/099d2c47))
 - Integer overflow in str_check_length ([6afff1c3](https://github.com/mruby/mruby/commit/6afff1c3))
 - Integer overflow in Integer#lcm ([070bef24](https://github.com/mruby/mruby/commit/070bef24))
+- Heap buffer overflow in `#method_missing` ([550d10a](https://github.com/mruby/mruby/commit/550d10a))
+- Out-of-bounds read and divide-by-zero in `Array#product` ([8441eaf](https://github.com/mruby/mruby/commit/8441eaf))
 - Multiple memory leak fixes in bigint, Set, Array, and Task gems
@@ -30,7 +30,7 @@ MRuby::CrossBuild.new("ArduinoDue") do |conf|

    #configuration for low memory environment
    cc.defines << %w(MRB_HEAP_PAGE_SIZE=64)
-    cc.defines << %w(KHASH_DEFAULT_SIZE=8)
+    cc.defines << %w(KHASH_INITIAL_SIZE=8)
    cc.defines << %w(MRB_GC_STRESS)
    #cc.defines << %w(MRB_NO_STDIO) #if you don't need stdio.
    #cc.defines << %w(POOL_PAGE_SIZE=1000) #effective only for use with mruby-eval
@@ -16,7 +16,7 @@ MRuby::CrossBuild.new("RX630") do |conf|
    #configuration for low memory environment
    cc.defines << %w(MRB_USE_FLOAT32)
    cc.defines << %w(MRB_HEAP_PAGE_SIZE=64)
-    cc.defines << %w(KHASH_DEFAULT_SIZE=8)
+    cc.defines << %w(KHASH_INITIAL_SIZE=8)
    cc.defines << %w(MRB_GC_STRESS)
    cc.defines << %w(MRB_NO_STDIO) #if you don't need stdio.
    #cc.defines << %w(POOL_PAGE_SIZE=1000) #effective only for use with mruby-eval
@@ -27,7 +27,7 @@ MRuby::CrossBuild.new("chipKITMax32") do |conf|

    #configuration for low memory environment
    cc.defines << %w(MRB_HEAP_PAGE_SIZE=64)
-    cc.defines << %w(KHASH_DEFAULT_SIZE=8)
+    cc.defines << %w(KHASH_INITIAL_SIZE=8)
    cc.defines << %w(MRB_GC_STRESS)
    #cc.defines << %w(MRB_NO_STDIO) #if you don't need stdio.
    #cc.defines << %w(POOL_PAGE_SIZE=1000) #effective only for use with mruby-eval
@@ -233,10 +233,10 @@ end
 - Specifies 4th argument(`argc`) max value of `mrb_funcall`.
 - Raises `ArgumentError` when the `argc` argument is bigger then this value `mrb_funcall`.

-`KHASH_DEFAULT_SIZE`
+`KHASH_INITIAL_SIZE`

 - Default value is `32`.
- Specifies default size of khash table bucket.
+- Specifies initial size of khash table bucket.
 - Used in `kh_init_ ## name` function.

 `MRB_NO_METHOD_CACHE`
@@ -272,7 +272,7 @@ deployment targets. Define one of the following:
 `MRB_CONSTRAINED_BASELINE_PROFILE`

 - For micro controllers.
- Enables `MRB_NO_METHOD_CACHE`, reduces `KHASH_DEFAULT_SIZE` to `16`,
+- Enables `MRB_NO_METHOD_CACHE`, reduces `KHASH_INITIAL_SIZE` to `16`,
  and `MRB_HEAP_PAGE_SIZE` to `256`.

 `MRB_BASELINE_PROFILE`
@@ -138,8 +138,8 @@
 /* turn off generational GC by default */
 //#define MRB_GC_TURN_OFF_GENERATIONAL

-/* default size of khash table bucket */
-//#define KHASH_DEFAULT_SIZE 32
+/* initial size of khash table bucket */
+//#define KHASH_INITIAL_SIZE 32

 /* allocated memory address alignment */
 //#define POOL_ALIGNMENT 4
@@ -208,8 +208,8 @@
 #  define MRB_NO_METHOD_CACHE
 # endif

-# ifndef KHASH_DEFAULT_SIZE
-#  define KHASH_DEFAULT_SIZE 16
+# ifndef KHASH_INITIAL_SIZE
+#  define KHASH_INITIAL_SIZE 16
 # endif

 # ifndef MRB_HEAP_PAGE_SIZE
@@ -21,7 +21,7 @@ typedef uint32_t khint_t;
 typedef khint_t khiter_t;

 #ifndef KHASH_INITIAL_SIZE
-# define KHASH_INITIAL_SIZE 8
+# define KHASH_INITIAL_SIZE 32
 #endif
 #define KHASH_MIN_SIZE 8
 #define KHASH_SMALL_LIMIT 4
@@ -316,7 +316,11 @@ struct RCptr {
 #endif
 #define mrb_test(o)   mrb_bool(o)
 #ifndef mrb_bigint_p
+#ifdef MRB_USE_BIGINT
 #define mrb_bigint_p(o) (mrb_type(o) == MRB_TT_BIGINT)
+#else
+#define mrb_bigint_p(o) FALSE
+#endif
 #endif

 /**
@@ -611,37 +611,15 @@ class Array
  #   ary.product(*arys)                  ->   array
  #   ary.product(*arys) { |item| ... }   ->   self
  def product(*arys, &block)
-    size = arys.size
-    i = size
-    while i > 0
-      i -= 1
-      unless arys[i].kind_of?(Array)
-        raise TypeError, "no implicit conversion into Array"
+    gen = __product_generate(arys, &block)
+    return gen unless block
+
+    if gen
+      while group = __product_next(arys, gen)
+        yield group
      end
    end
-
-    i = size
-    total = self.size
-    total *= arys[i -= 1].size while i > 0
-
-    if block
-      i = 0
-      while i < total
-        group = self.__product_group(arys, i, size + 1)
-        block.call(group)
-        i += 1
-      end
-      return self
-    else
-      result = [nil] * total
-      i = 0
-      while i < total
-        group = self.__product_group(arys, i, size + 1)
-        result[i] = group
-        i += 1
-      end
-      return result
-    end
+    self
  end

  ##
@@ -6,6 +6,7 @@
 #include <mruby/hash.h>
 #include <mruby/data.h>
 #include <mruby/class.h>
+#include <mruby/numeric.h>
 #include <mruby/internal.h>
 #include <mruby/khash.h>
 #include <mruby/error.h>
@@ -78,11 +79,14 @@ ary_assoc(mrb_state *mrb, mrb_value ary)
 {
  mrb_value k = mrb_get_arg1(mrb);

+  int ai = mrb_gc_arena_save(mrb);
  for (mrb_int i = 0; i < RARRAY_LEN(ary); i++) {
    mrb_value v = mrb_check_array_type(mrb, RARRAY_PTR(ary)[i]);
+    mrb_gc_protect(mrb, v); // v may be removed from ary by mrb_equal()
    if (!mrb_nil_p(v) && RARRAY_LEN(v) > 0 &&
        mrb_equal(mrb, RARRAY_PTR(v)[0], k))
      return v;
+    mrb_gc_arena_restore(mrb, ai);
  }
  return mrb_nil_value();
 }
@@ -106,12 +110,15 @@ ary_rassoc(mrb_state *mrb, mrb_value ary)
 {
  mrb_value value = mrb_get_arg1(mrb);

+  int ai = mrb_gc_arena_save(mrb);
  for (mrb_int i = 0; i < RARRAY_LEN(ary); i++) {
    mrb_value v = RARRAY_PTR(ary)[i];
+    mrb_gc_protect(mrb, v); // v may be removed from ary by mrb_equal()
    if (mrb_array_p(v) &&
        RARRAY_LEN(v) > 1 &&
        mrb_equal(mrb, RARRAY_PTR(v)[1], value))
      return v;
+    mrb_gc_arena_restore(mrb, ai);
  }
  return mrb_nil_value();
 }
@@ -409,9 +416,12 @@ ary_init_temp_set(mrb_state *mrb, ary_set_t *set, mrb_int capacity)
 static void
 ary_populate_temp_set(mrb_state *mrb, ary_set_t *set, mrb_value ary)
 {
-  mrb_int len = RARRAY_LEN(ary);
-  for (mrb_int i = 0; i < len; i++) {
-    kh_put(ary_set, mrb, set, RARRAY_PTR(ary)[i]);
+  int ai = mrb_gc_arena_save(mrb);
+  for (mrb_int i = 0; i < RARRAY_LEN(ary); i++) {
+    mrb_value p = RARRAY_PTR(ary)[i];
+    mrb_gc_protect(mrb, p); // p may be removed from ary by kh_put(ary_set, ...)
+    kh_put(ary_set, mrb, set, p);
+    mrb_gc_arena_restore(mrb, ai);
  }
 }

@@ -460,12 +470,15 @@ ary_subtract_body(mrb_state *mrb, void *data)
    ary_populate_temp_set(mrb, ctx->set, ctx->argv[i]);
  }

+  int ai = mrb_gc_arena_save(mrb);
  for (mrb_int i = 0; i < RARRAY_LEN(ctx->self); i++) {
    mrb_value p = RARRAY_PTR(ctx->self)[i];
+    mrb_gc_protect(mrb, p); // p may be removed from self by kh_get(ary_set, ...)
    khiter_t k = kh_get(ary_set, mrb, ctx->set, p);
    if (kh_is_end(ctx->set, k)) {  /* key doesn't exist in any ary */
      mrb_ary_push(mrb, ctx->result, p);
    }
+    mrb_gc_arena_restore(mrb, ai);
  }

  return ctx->result;
@@ -499,13 +512,13 @@ ary_subtract_internal(mrb_state *mrb, mrb_value self, mrb_int argc, const mrb_va
    }
  }
  else {
-    mrb_int self_len = RARRAY_LEN(self);
-    for (mrb_int i = 0; i < self_len; i++) {
+    int ai = mrb_gc_arena_save(mrb);
+    for (mrb_int i = 0; i < RARRAY_LEN(self); i++) {
      mrb_value p = RARRAY_PTR(self)[i];
+      mrb_gc_protect(mrb, p); // p may be removed from self by mrb_equal()
      mrb_bool found = FALSE;
      for (mrb_int j = 0; j < argc; j++) {
-        mrb_int len = RARRAY_LEN(argv[j]);
-        for (mrb_int k = 0; k < len; k++) {
+        for (mrb_int k = 0; k < RARRAY_LEN(argv[j]); k++) {
          if (mrb_equal(mrb, p, RARRAY_PTR(argv[j])[k])) {
            found = TRUE;
            break;
@@ -516,6 +529,7 @@ ary_subtract_internal(mrb_state *mrb, mrb_value self, mrb_int argc, const mrb_va
      if (!found) {
        mrb_ary_push(mrb, result, p);
      }
+      mrb_gc_arena_restore(mrb, ai);
    }
  }

@@ -559,12 +573,10 @@ ary_difference(mrb_state *mrb, mrb_value self)
  return ary_subtract_internal(mrb, self, argc, argv);
 }

-
 static void
 add_uniq(mrb_state *mrb, mrb_value item, mrb_value result)
 {
-  const mrb_int len = RARRAY_LEN(result);
-  for (mrb_int i = 0; i < len; i++) {
+  for (mrb_int i = 0; i < RARRAY_LEN(result); i++) {
    if (mrb_eql(mrb, item, RARRAY_PTR(result)[i])) {
      return;
    }
@@ -584,15 +596,18 @@ static mrb_value
 ary_union_body(mrb_state *mrb, void *data)
 {
  struct ary_union_ctx *ctx = (struct ary_union_ctx *)data;
+  int ai = mrb_gc_arena_save(mrb);

  /* Add unique elements from self */
  for (mrb_int i = 0; i < RARRAY_LEN(ctx->self_copy); i++) {
    mrb_value elem = RARRAY_PTR(ctx->self_copy)[i];
+    mrb_gc_protect(mrb, elem); // elem may be removed from self_copy by kh_get(ary_set, ...)
    khiter_t k = kh_get(ary_set, mrb, ctx->set, elem);
    if (kh_is_end(ctx->set, k)) {
      kh_put(ary_set, mrb, ctx->set, elem);
      mrb_ary_push(mrb, ctx->result, elem);
    }
+    mrb_gc_arena_restore(mrb, ai);
  }

  /* Add unique elements from others */
@@ -600,11 +615,13 @@ ary_union_body(mrb_state *mrb, void *data)
    mrb_value other = ctx->argv[i];
    for (mrb_int j = 0; j < RARRAY_LEN(other); j++) {
      mrb_value elem = RARRAY_PTR(other)[j];
+      mrb_gc_protect(mrb, elem); // elem may be removed from other by kh_get(ary_set, ...)
      khiter_t k = kh_get(ary_set, mrb, ctx->set, elem);
      if (kh_is_end(ctx->set, k)) {
        kh_put(ary_set, mrb, ctx->set, elem);
        mrb_ary_push(mrb, ctx->result, elem);
      }
+      mrb_gc_arena_restore(mrb, ai);
    }
  }

@@ -636,19 +653,25 @@ ary_union_internal(mrb_state *mrb, mrb_value self, mrb_int argc, const mrb_value
    }
  }
  else {
+    int ai = mrb_gc_arena_save(mrb);
+
    /* Use linear search for small arrays */
    /* Add unique elements from self */
-    mrb_int alen = RARRAY_LEN(self);
-    for (mrb_int i = 0; i < alen; i++) {
-      add_uniq(mrb, RARRAY_PTR(self)[i], result);
+    for (mrb_int i = 0; i < RARRAY_LEN(self); i++) {
+      mrb_value p = RARRAY_PTR(self)[i];
+      mrb_gc_protect(mrb, p); // p may be removed from self by add_uniq()
+      add_uniq(mrb, p, result);
+      mrb_gc_arena_restore(mrb, ai);
    }

    /* Add unique elements from others */
    for (mrb_int i = 0; i < argc; i++) {
      mrb_value other = argv[i];
-      mrb_int olen = RARRAY_LEN(other);
-      for (mrb_int j = 0; j < olen; j++) {
-        add_uniq(mrb, RARRAY_PTR(other)[j], result);
+      for (mrb_int j = 0; j < RARRAY_LEN(other); j++) {
+        mrb_value p = RARRAY_PTR(other)[j];
+        mrb_gc_protect(mrb, p); // p may be removed from other by add_uniq()
+        add_uniq(mrb, p, result);
+        mrb_gc_arena_restore(mrb, ai);
      }
    }
  }
@@ -711,13 +734,16 @@ ary_intersection_body(mrb_state *mrb, void *data)
    ary_populate_temp_set(mrb, ctx->set, ctx->argv[i]);
  }

+  int ai = mrb_gc_arena_save(mrb);
  for (mrb_int i = 0; i < RARRAY_LEN(ctx->self); i++) {
    mrb_value p = RARRAY_PTR(ctx->self)[i];
+    mrb_gc_protect(mrb, p); // p may be removed from self by kh_get(ary_set, ...)
    khiter_t k = kh_get(ary_set, mrb, ctx->set, p);
    if (!kh_is_end(ctx->set, k)) {
      mrb_ary_push(mrb, ctx->result, p);
      kh_del(ary_set, mrb, ctx->set, k);
    }
+    mrb_gc_arena_restore(mrb, ai);
  }

  return ctx->result;
@@ -751,15 +777,15 @@ ary_intersection_internal(mrb_state *mrb, mrb_value self, mrb_int argc, const mr
    }
  }
  else {
-    mrb_int self_len = RARRAY_LEN(self);
-    for (mrb_int i = 0; i < self_len; i++) {
+    int ai = mrb_gc_arena_save(mrb);
+    for (mrb_int i = 0; i < RARRAY_LEN(self); i++) {
      mrb_value p = RARRAY_PTR(self)[i];
+      mrb_gc_protect(mrb, p); // p may be removed from self by mrb_equal()
      mrb_bool found_in_all = TRUE;

      for (mrb_int j = 0; j < argc; j++) {
        mrb_bool found_in_current_other = FALSE;
-        mrb_int len = RARRAY_LEN(argv[j]);
-        for (mrb_int k = 0; k < len; k++) {
+        for (mrb_int k = 0; k < RARRAY_LEN(argv[j]); k++) {
          if (mrb_equal(mrb, p, RARRAY_PTR(argv[j])[k])) {
            found_in_current_other = TRUE;
            break;
@@ -773,8 +799,7 @@ ary_intersection_internal(mrb_state *mrb, mrb_value self, mrb_int argc, const mr

      if (found_in_all) {
        mrb_bool already_added = FALSE;
-        mrb_int result_len = RARRAY_LEN(result);
-        for (mrb_int j = 0; j < result_len; j++) {
+        for (mrb_int j = 0; j < RARRAY_LEN(result); j++) {
          if (mrb_equal(mrb, p, RARRAY_PTR(result)[j])) {
            already_added = TRUE;
            break;
@@ -784,6 +809,7 @@ ary_intersection_internal(mrb_state *mrb, mrb_value self, mrb_int argc, const mr
          mrb_ary_push(mrb, result, p);
        }
      }
+      mrb_gc_arena_restore(mrb, ai);
    }
  }
  return result;
@@ -854,8 +880,12 @@ ary_intersect_p_body(mrb_state *mrb, void *data)

  ary_populate_temp_set(mrb, ctx->set, ctx->shorter_ary_copy);

+  int ai = mrb_gc_arena_save(mrb);
  for (mrb_int i = 0; i < RARRAY_LEN(ctx->longer_ary); i++) {
-    khiter_t k = kh_get(ary_set, mrb, ctx->set, RARRAY_PTR(ctx->longer_ary)[i]);
+    mrb_value p = RARRAY_PTR(ctx->longer_ary)[i];
+    mrb_gc_protect(mrb, p); // p may be removed from longer_ary by kh_get(ary_set, ...)
+    khiter_t k = kh_get(ary_set, mrb, ctx->set, p);
+    mrb_gc_arena_restore(mrb, ai);
    if (!kh_is_end(ctx->set, k)) {
      *ctx->found = TRUE;
      break;
@@ -905,12 +935,16 @@ ary_intersect_p(mrb_state *mrb, mrb_value self)
    }
  }
  else {
+    int ai = mrb_gc_arena_save(mrb);
    for (mrb_int i = 0; i < RARRAY_LEN(longer_ary); i++) {
+      mrb_value p = RARRAY_PTR(longer_ary)[i];
+      mrb_gc_protect(mrb, p); // p may be removed from longer_ary by mrb_equal()
      for (mrb_int j = 0; j < RARRAY_LEN(shorter_ary); j++) {
-        if (mrb_equal(mrb, RARRAY_PTR(longer_ary)[i], RARRAY_PTR(shorter_ary)[j])) {
+        if (mrb_equal(mrb, p, RARRAY_PTR(shorter_ary)[j])) {
          return mrb_true_value();
        }
      }
+      mrb_gc_arena_restore(mrb, ai);
    }
  }

@@ -1041,6 +1075,7 @@ ary_fill_exec(mrb_state *mrb, mrb_value self)
  }

  /* Fill the array */
+  mrb_ary_modify(mrb, ary);
  mrb_value *ptr = ARY_PTR(ary) + start;
  for (mrb_int i = 0; i < length; i++) {
    ptr[i] = obj;
@@ -1058,7 +1093,6 @@ struct ary_uniq_bang_ctx {
  mrb_value self_copy;
  mrb_value self;
  mrb_int *write_pos;
-  mrb_int len;
 };

 static mrb_value
@@ -1068,15 +1102,19 @@ ary_uniq_bang_body(mrb_state *mrb, void *data)

  ary_populate_temp_set(mrb, ctx->set, ctx->self_copy);

-  for (mrb_int read_pos = 0; read_pos < ctx->len; read_pos++) {
+  int ai = mrb_gc_arena_save(mrb);
+  for (mrb_int read_pos = 0; read_pos < RARRAY_LEN(ctx->self); read_pos++) {
    mrb_value elem = RARRAY_PTR(ctx->self)[read_pos];
+    mrb_gc_protect(mrb, elem); // elem may be removed from self by kh_get(ary_set, ...)
    khiter_t k = kh_get(ary_set, mrb, ctx->set, elem);
    if (!kh_is_end(ctx->set, k)) {
-      if (*ctx->write_pos != read_pos) {
+      if (*ctx->write_pos != read_pos && *ctx->write_pos < RARRAY_LEN(ctx->self)) {
+        mrb_ary_modify(mrb, mrb_ary_ptr(ctx->self));
        RARRAY_PTR(ctx->self)[*ctx->write_pos] = elem;
      }
      (*ctx->write_pos)++;
      kh_del(ary_set, mrb, ctx->set, k);
+      mrb_gc_arena_restore(mrb, ai);
    }
  }

@@ -1103,28 +1141,32 @@ ary_uniq_bang(mrb_state *mrb, mrb_value self)
    ary_set_t *set = &set_struct;
    ary_init_temp_set(mrb, set, len);

-    struct ary_uniq_bang_ctx ctx = { set, self_copy, self, &write_pos, len };
+    struct ary_uniq_bang_ctx ctx = { set, self_copy, self, &write_pos };
    mrb_value result;
    MRB_ENSURE(mrb, result, ary_uniq_bang_body, &ctx) {
      ary_destroy_temp_set(mrb, set);
    }
  }
  else {
-    for (mrb_int read_pos = 0; read_pos < len; read_pos++) {
+    int ai = mrb_gc_arena_save(mrb);
+    for (mrb_int read_pos = 0; read_pos < RARRAY_LEN(self); read_pos++) {
      mrb_value elem = RARRAY_PTR(self)[read_pos];
+      mrb_gc_protect(mrb, elem); // elem may be removed from self by mrb_equal()
      mrb_bool found = FALSE;
-      for (mrb_int j = 0; j < write_pos; j++) {
+      for (mrb_int j = 0; j < write_pos && j < RARRAY_LEN(self); j++) {
        if (mrb_equal(mrb, elem, RARRAY_PTR(self)[j])) {
          found = TRUE;
          break;
        }
      }
      if (!found) {
-        if (write_pos != read_pos) {
+        if (write_pos != read_pos && write_pos < RARRAY_LEN(self)) {
+          mrb_ary_modify(mrb, mrb_ary_ptr(self));
          RARRAY_PTR(self)[write_pos] = elem;
        }
        write_pos++;
      }
+      mrb_gc_arena_restore(mrb, ai);
    }
  }

@@ -1373,6 +1415,13 @@ ary_insert(mrb_state *mrb, mrb_value self)
  return self;
 }

+struct ary_product_generator {
+  mrb_int total;
+  mrb_int cursor;
+};
+
+static struct mrb_data_type ary_product_generator_type = { "ary_product_generator", mrb_free };
+
 /*
 *  Internal helper for Array#product to construct a group array.
 *  Takes the base array (self), the array of other arrays (arys),
@@ -1380,29 +1429,85 @@ ary_insert(mrb_state *mrb, mrb_value self)
 *  of the group array (group_len).
 */
 static mrb_value
-ary_product_group(mrb_state *mrb, mrb_value self_ary)
+ary_product_fetch(mrb_state *mrb, mrb_value self_ary, mrb_value arys_ary, mrb_int n)
 {
-  mrb_value arys_ary;
-  mrb_int current_i, group_len;
-  mrb_get_args(mrb, "Aii", &arys_ary, &current_i, &group_len);
-
-  mrb_value group = mrb_ary_new_capa(mrb, group_len);
  mrb_int j = RARRAY_LEN(arys_ary); // Corresponds to 'size' in Ruby
-  mrb_int n = current_i;
+  mrb_value group = mrb_ary_new_capa(mrb, j + 1 /* self_ary */);

-  while (j > 0) {
-    j -= 1;
+  while (j-- > 0) {
    mrb_value a = RARRAY_PTR(arys_ary)[j]; // arys[j]
    mrb_check_type(mrb, a, MRB_TT_ARRAY);
    mrb_int b = RARRAY_LEN(a);             // a.size
+    if (b <= 0) {
+      mrb_raise(mrb, E_ARGUMENT_ERROR, "cannot compute product with an empty array");
+    }
    mrb_ary_set(mrb, group, j + 1, RARRAY_PTR(a)[n % b]);
    n /= b;
  }
+  if (n >= RARRAY_LEN(self_ary)) {
+    mrb_raise(mrb, E_INDEX_ERROR, "index out of range");
+  }
  mrb_ary_set(mrb, group, 0, RARRAY_PTR(self_ary)[n]);

  return group;
 }

+static mrb_value
+ary_product_generate(mrb_state *mrb, mrb_value self)
+{
+  mrb_value arys_ary, block;
+  mrb_get_args(mrb, "A&", &arys_ary, &block);
+
+  mrb_int total = RARRAY_LEN(self);
+  for (mrb_int i = 0; i < RARRAY_LEN(arys_ary); i++) {
+    mrb_value a = RARRAY_PTR(arys_ary)[i];
+    mrb_check_type(mrb, a, MRB_TT_ARRAY);
+    mrb_int n = RARRAY_LEN(a);
+    if (n == 0) {
+      total = 0;
+      break;
+    }
+    if (mrb_int_mul_overflow(total, n, &total)) {
+      mrb_raise(mrb, E_ARGUMENT_ERROR, "result too big");
+    }
+  }
+
+  if (mrb_nil_p(block)) {
+    mrb_value result = mrb_ary_new_capa(mrb, total);
+    for (mrb_int i = 0; i < total; i++) {
+      mrb_value group = ary_product_fetch(mrb, self, arys_ary, i);
+      mrb_ary_push(mrb, result, group);
+    }
+    return result;
+  }
+  else if (total > 0) {
+    struct RData *d;
+    struct ary_product_generator *g;
+    Data_Make_Struct(mrb, mrb->object_class, struct ary_product_generator,
+                     &ary_product_generator_type, g, d);
+    g->total = total;
+    g->cursor = 0;
+    return mrb_obj_value(d);
+  }
+  else {
+    return mrb_nil_value();
+  }
+}
+
+static mrb_value
+ary_product_next(mrb_state *mrb, mrb_value self)
+{
+  mrb_value arys;
+  struct ary_product_generator *g;
+  mrb_get_args(mrb, "Ad", &arys, &g, &ary_product_generator_type);
+
+  if (g->cursor >= g->total) {
+    return mrb_nil_value();
+  }
+
+  return ary_product_fetch(mrb, self, arys, g->cursor++);
+}
+
 /*
 *  call-seq:
 *     ary.deconstruct -> ary
@@ -1563,7 +1668,8 @@ static const mrb_mt_entry array_ext_rom_entries[] = {
  MRB_MT_ENTRY(ary_fetch,              MRB_SYM(__fetch),            MRB_ARGS_REQ(3)),
  MRB_MT_ENTRY(ary_insert,             MRB_SYM(insert),             MRB_ARGS_ARG(1,-1)),
  MRB_MT_ENTRY(ary_deconstruct,        MRB_SYM(deconstruct),        MRB_ARGS_NONE()),
-  MRB_MT_ENTRY(ary_product_group,      MRB_SYM(__product_group),    MRB_ARGS_REQ(3)),
+  MRB_MT_ENTRY(ary_product_generate,   MRB_SYM(__product_generate), MRB_ARGS_REQ(1)),
+  MRB_MT_ENTRY(ary_product_next,       MRB_SYM(__product_next),     MRB_ARGS_REQ(2)),
  MRB_MT_ENTRY(ary_combination_init,   MRB_SYM(__combination_init), MRB_ARGS_REQ(2)),
  MRB_MT_ENTRY(ary_combination_next,   MRB_SYM(__combination_next), MRB_ARGS_REQ(1)),
 };
@@ -3260,7 +3260,7 @@ primary         : literal
                      $<stack>$ = p->cmdarg_stack;
                      p->cmdarg_stack = 0;
                    }
-                  stmt {p->lstate = EXPR_ENDARG;} rparen
+                  compstmt {p->lstate = EXPR_ENDARG;} rparen
                    {
                      p->cmdarg_stack = $<stack>2;
                      $$ = $3;
@@ -4563,13 +4563,13 @@ f_label         : tIDENTIFIER tLABEL_TAG
                    {
                      $$ = $1;
                      local_nest(p);
-                      p->lstate = EXPR_ARG;  /* make newlines significant after label */
+                      p->lstate = EXPR_MID;  /* make newlines significant after label */
                    }
                | tNUMPARAM tLABEL_TAG
                    {
                      $$ = intern_numparam($1);
                      local_nest(p);
-                      p->lstate = EXPR_ARG;  /* make newlines significant after label */
+                      p->lstate = EXPR_MID;  /* make newlines significant after label */
                    }
                ;

@@ -291,11 +291,12 @@ class Enumerator
    #
    def flat_map(&block)
      Lazy.new(self){|yielder, val|
-        ary = block.call(val)
-        # TODO: check ary is an Array
-        ary.each {|x|
-          yielder << x
-        }
+        result = block.call(val)
+        if result.respond_to?(:each)
+          result.each {|x| yielder << x }
+        else
+          yielder << result
+        end
      }
    end
    alias collect_concat flat_map
@@ -46,6 +46,18 @@ assert("Enumerator::Lazy#to_enum") do
  assert_equal [0*1, 2*3, 4*5, 6*7], lazy_enum.map { |a| a.first * a.last }.first(4)
 end

+assert("Enumerator::Lazy#flat_map with array from block") do
+  assert_equal [1, 10, 2, 20, 3, 30], [1, 2, 3].lazy.flat_map {|x| [x, x*10]}.force
+end
+
+assert("Enumerator::Lazy#flat_map with non-enumerable from block") do
+  assert_equal [1, 2, 3], [1, 2, 3].lazy.flat_map {|x| x}.force
+end
+
+assert("Enumerator::Lazy#flat_map with nested array from block") do
+  assert_equal [[1, 2], [3, 4]], [1, 3].lazy.flat_map {|x| [[x, x+1]]}.force
+end
+
 assert("Enumerator::Lazy#grep_v") do
  lazy_grep_v = (0..).lazy.grep_v(2..4)
  assert_kind_of Enumerator::Lazy, lazy_grep_v
@@ -190,11 +190,7 @@ int_powm(mrb_state *mrb, mrb_value x)
    return mrb_int_pow(mrb, x, mrb_get_arg1(mrb));
  }
  mrb_get_args(mrb, "oo", &e, &m);
-  if (!mrb_integer_p(e)
-#ifdef MRB_USE_BIGINT
-      && !mrb_bigint_p(e)
-#endif
-      ) {
+  if (!mrb_integer_p(e) && !mrb_bigint_p(e)) {
    mrb_raise(mrb, E_TYPE_ERROR, "int.pow(n,m): 2nd argument not allowed unless 1st argument is an integer");
  }
 #ifdef MRB_USE_BIGINT
@@ -19,9 +19,11 @@ MRuby::Gem::Specification.new('mruby-test') do |spec|
  file assert_c => [assert_rb, build.mrbcfile] do |t|
    _pp "GEN", t.name.relative_path
    mkdir_p File.dirname(t.name)
-    open(t.name, 'w') do |f|
+    tmpfile = t.name + ".tmp"
+    open(tmpfile, 'w') do |f|
      mrbc.run f, assert_rb, 'mrbtest_assert_irep', cdump: false
    end
+    File.rename(tmpfile, t.name)
  end

  gem_table = build.gems.generate_gem_table build
@@ -36,7 +38,8 @@ MRuby::Gem::Specification.new('mruby-test') do |spec|
    file g.test_rbireps => [g.test_rbfiles, build.mrbcfile].flatten do |t|
      _pp "GEN", t.name.relative_path
      mkdir_p File.dirname(t.name)
-      open(t.name, 'w') do |f|
+      tmpfile = t.name + ".tmp"
+      open(tmpfile, 'w') do |f|
        g.print_gem_test_header(f)
        test_preload = g.test_preload and [g.dir, MRUBY_ROOT].map {|dir|
          File.expand_path(g.test_preload, dir)
@@ -117,6 +120,7 @@ MRuby::Gem::Specification.new('mruby-test') do |spec|
        end
        f.puts %Q[}]
      end
+      File.rename(tmpfile, t.name)
    end
  end

@@ -134,7 +138,8 @@ MRuby::Gem::Specification.new('mruby-test') do |spec|
  file clib => ["#{build.build_dir}/mrbgems/active_gems.txt", build.mrbcfile, __FILE__] do |_t|
    _pp "GEN", clib.relative_path
    mkdir_p File.dirname(clib)
-    open(clib, 'w') do |f|
+    tmpfile = clib + ".tmp"
+    open(tmpfile, 'w') do |f|
      f.puts %Q[/*]
      f.puts %Q[ * This file contains a list of all]
      f.puts %Q[ * test functions.]
@@ -169,5 +174,6 @@ MRuby::Gem::Specification.new('mruby-test') do |spec|
      end
      f.puts %Q[}]
    end
+    File.rename(tmpfile, clib)
  end
 end
@@ -2748,7 +2748,7 @@ prepare_writer_name(mrb_state *mrb, mrb_sym sym)
 }

 static mrb_value
-mod_attr_define(mrb_state *mrb, mrb_value mod, mrb_value (*accessor)(mrb_state*, mrb_value), mrb_sym (*access_name)(mrb_state*, mrb_sym))
+mod_attr_define(mrb_state *mrb, mrb_value mod, mrb_int aargc, mrb_value (*accessor)(mrb_state*, mrb_value), mrb_sym (*access_name)(mrb_state*, mrb_sym))
 {
  struct RClass *c = mrb_class_ptr(mod);
  const mrb_value *argv;
@@ -2765,6 +2765,7 @@ mod_attr_define(mrb_state *mrb, mrb_value mod, mrb_value (*accessor)(mrb_state*,
    }

    struct RProc *p = mrb_proc_new_cfunc_with_env(mrb, accessor, 1, &name);
+    p->flags |= aargc == 0 ? MRB_PROC_NOARG : 0;
    mrb_method_t m;
    MRB_METHOD_FROM_PROC(m, p);
    mrb_define_method_raw(mrb, c, method, m);
@@ -2783,7 +2784,7 @@ attr_reader(mrb_state *mrb, mrb_value obj)
 static mrb_value
 mrb_mod_attr_reader(mrb_state *mrb, mrb_value mod)
 {
-  return mod_attr_define(mrb, mod, attr_reader, NULL);
+  return mod_attr_define(mrb, mod, 0, attr_reader, NULL);
 }

 static mrb_value
@@ -2799,7 +2800,7 @@ attr_writer(mrb_state *mrb, mrb_value obj)
 static mrb_value
 mrb_mod_attr_writer(mrb_state *mrb, mrb_value mod)
 {
-  return mod_attr_define(mrb, mod, attr_writer, prepare_writer_name);
+  return mod_attr_define(mrb, mod, 1, attr_writer, prepare_writer_name);
 }

 static mrb_value
@@ -541,15 +541,15 @@ mrb_gc_unregister(mrb_state *mrb, mrb_value obj)
  if (!mrb_array_p(table)) return;
  struct RArray *a = mrb_ary_ptr(table);
  mrb_ary_modify(mrb, a);
-  mrb_int len = ARY_LEN(a)-1;
+  mrb_int len = ARY_LEN(a);
  mrb_value *ptr = ARY_PTR(a);
-  for (mrb_int i = 0; i <= len; i++) {
-    if (mrb_ptr(ptr[i]) == mrb_ptr(obj)) {
-      ARY_SET_LEN(a, len);
-      memmove(&ptr[i], &ptr[i + 1], (len - i) * sizeof(mrb_value));
-      break;
+  mrb_int w = 0;
+  for (mrb_int r = 0; r < len; r++) {
+    if (mrb_ptr(ptr[r]) != mrb_ptr(obj)) {
+      ptr[w++] = ptr[r];
    }
  }
+  ARY_SET_LEN(a, w);
 }

 MRB_API struct RBasic*
@@ -432,11 +432,7 @@ mrb_get_values_at(mrb_state *mrb, mrb_value obj, mrb_int olen, mrb_int argc, con
  for (mrb_int i = 0; i < argc; i++) {
    mrb_value v = argv[i];

-    if (mrb_integer_p(v)
-#ifdef MRB_USE_BIGINT
-        || mrb_bigint_p(v)
-#endif
-        ) {
+    if (mrb_integer_p(v) || mrb_bigint_p(v)) {
      mrb_int i = mrb_as_int(mrb, v);
      mrb_ary_push(mrb, result, func(mrb, obj, i));
    }
@@ -2703,11 +2703,10 @@ RETRY_TRY_BLOCK:
      if (kidx < 0 || !mrb_hash_p(kdict=regs[kidx]) || !mrb_hash_key_p(mrb, kdict, k)) {
        RAISE_FORMAT(mrb, E_ARGUMENT_ERROR, "missing keyword: %v", k);
      }
-      v = mrb_hash_get(mrb, kdict, k);
+
+      v = mrb_hash_delete_key(mrb, kdict, k);
      ci = mrb->c->ci;
      regs[a] = v;
-      mrb_hash_delete_key(mrb, kdict, k);
-      ci = mrb->c->ci;
      NEXT;
    }

@@ -3113,7 +3112,9 @@ RETRY_TRY_BLOCK:
      {                                                                     \
        mrb_value arg = mrb_int_value(mrb, c);                              \
        mrb_sym mid = MRB_OPSYM(op_name);                                   \
-        regs[a] = mrb_funcall_argv(mrb, regs[a], mid, 1, &arg);             \
+        mrb_value v = mrb_funcall_argv(mrb, regs[a], mid, 1, &arg);         \
+        ci = mrb->c->ci;                                                    \
+        regs[a] = v;                                                        \
        mrb_gc_arena_restore(mrb, ai);                                      \
      }                                                                     \
      break;                                                                \
@@ -29,7 +29,7 @@ MRuby.each_target do |build|
    end
  end

-  file presym.list_path => ppps do
+  presym_task = file presym.list_path => ppps do
    presyms = presym.scan(ppps)
    current_presyms = presym.read_list if File.exist?(presym.list_path)
    if presyms != current_presyms
@@ -41,6 +41,21 @@ MRuby.each_target do |build|
    end
  end

+  # Don't directly write dependency tasks in the "task" arguments.
+  # The rake system tracks dependencies recursively
+  # (see Rake::Task#all_prerequisite_tasks and #collect_prerequisites).
+  # Therefore, indirect dependencies from ".o" to ".pi" must be eliminated.
+  # ref. https://github.com/mruby/mruby/issues/6721
+  # This task acts a proxy-like for the "presym.list_path" task.
+  presym_proxy = task "gensym:update:#{build.name}" do
+    presym_task.invoke
+  end
+
+  # Override the "timestamp" method to reflect the presym file.
+  presym_proxy.define_singleton_method :timestamp do
+    presym_task.timestamp
+  end
+
  # Ensure .o files depend on presym headers being generated.
  # This is critical when a build's .o files are compiled during another
  # build's presym scanning chain (before :gensym completes), e.g.:
@@ -50,7 +65,7 @@ MRuby.each_target do |build|
    next unless File.extname(prereq) == build.exts.object
    next unless prereq.start_with?(build_dir)
    next if mrbc_build_dir && prereq.start_with?(mrbc_build_dir)
-    file prereq => presym.list_path
+    file prereq => presym_proxy
  end

  task gensym: presym.list_path
@@ -163,6 +163,9 @@ assert('Module#attr_reader', '15.2.2.4.13') do

  AttrTestReader.cattr_val = 'test'
  assert_equal 'test', AttrTestReader.cattr
+
+  assert_raise(ArgumentError) { attr_instance.iattr(1) }
+  assert_raise(ArgumentError) { attr_instance.iattr(1, 2, 3) }
 end

 assert('Module#attr_writer', '15.2.2.4.14') do
@@ -680,6 +680,20 @@ assert 'keyword arguments' do
  assert_equal [{a: 1}, {b: 2}], m({a: 1}, b: 2)
  assert_raise(ArgumentError) { m({a: 1}, {b: 2}) }

+  def m1(a: {}) a end
+  assert_equal({}, m1)
+  assert_equal(:abc, m1(a: :abc))
+
+  def m2(a: +1) a end
+  assert_equal(1, m2)
+
+  assert_nothing_raised do
+    def m3 arg:
+      123
+    end
+  end
+  assert_equal(123, m3(arg: 456))
+
  def m(*, a:) a end
  assert_equal 1, m(a: 1)
  assert_equal 3, m(1, 2, a: 3)
Author	SHA1	Message	Date
Yukihiro "Matz" Matsumoto	3a5c45f282	NEWS.md: update for recent changes Add entries for language changes (case/in NoMatchingPatternError, compound statement in tLPAREN_ARG), C API additions (mrb_bigint_p(), RVALUE union), compiler optimizations (literal chunking), build fixes (MSYS2), security fixes, and 26 merged pull requests. Co-authored-by: Claude <noreply@anthropic.com>	2026-04-02 20:17:19 +09:00
Yukihiro "Matz" Matsumoto	ac9f7aedd2	Merge pull request #6767 from mruby/fix/lparen-arg-compstmt	2026-03-30 07:54:31 +09:00
Yukihiro "Matz" Matsumoto	919cbd8fea	mruby-compiler: allow compound statement in tLPAREN_ARG Change the grammar rule for tLPAREN_ARG from accepting only a single stmt to accepting compstmt. This allows compound statements with semicolons inside parenthesized arguments when the parenthesis is preceded by a space, e.g., `p (f1; f2)`. This matches the behavior of CRuby 3.3+. Fixes #6766. Co-authored-by: Claude <noreply@anthropic.com>	2026-03-30 07:06:30 +09:00
Yukihiro "Matz" Matsumoto	801eefeab6	Merge pull request #6765 from khasinski/fix-lazy-flat-map	2026-03-29 22:55:13 +09:00
Chris Hasiński	8f71887e46	Improve flat_map test descriptions for clarity	2026-03-28 23:14:46 +01:00
Chris Hasiński	3f52ef6cfc	Fix Lazy#flat_map to handle non-enumerable block return values When the block passed to Lazy#flat_map returns a non-enumerable value (e.g. an Integer), mruby raised NoMethodError because it unconditionally called #each on the result. CRuby yields non-enumerable values directly. Use respond_to?(:each) to match CRuby behavior: iterate enumerable results, yield non-enumerable results as-is.	2026-03-28 22:59:11 +01:00
Yukihiro "Matz" Matsumoto	28c5b1b17b	Merge pull request #6763 from mruby/dependabot/github_actions/github-actions-dependencies-19ba90ca6e	2026-03-26 14:27:05 +09:00
dependabot[bot]	d50932c50f	build(deps): bump j178/prek-action Bumps the github-actions-dependencies group with 1 update: [j178/prek-action](https://github.com/j178/prek-action). Updates `j178/prek-action` from 1 to 2 - [Release notes](https://github.com/j178/prek-action/releases) - [Commits](https://github.com/j178/prek-action/compare/v1...v2) --- updated-dependencies: - dependency-name: j178/prek-action dependency-version: '2' dependency-type: direct:production update-type: version-update:semver-major dependency-group: github-actions-dependencies ... Signed-off-by: dependabot[bot] <support@github.com>	2026-03-25 14:54:41 +00:00
Yukihiro "Matz" Matsumoto	b7e3743130	Merge pull request #6762 from mruby/fix-test-build-race	2026-03-25 15:49:46 +09:00
Yukihiro "Matz" Matsumoto	805e6dbc33	Merge pull request #6761 from mruby/fix-gc-unregister-leak	2026-03-25 15:44:44 +09:00
Yukihiro "Matz" Matsumoto	e8c5e7c0cd	mruby-test: write generated C files atomically to avoid race condition With `rake -m`, the C compiler can start reading a partially-written gem_test.c before generation completes. Write to a .tmp file first, then rename to the final path. Co-authored-by: Claude <noreply@anthropic.com>	2026-03-25 15:32:36 +09:00
Yukihiro "Matz" Matsumoto	ab249864cc	gc.c: remove all matching entries in mrb_gc_unregister() Previously only the first match was removed, leaking duplicate entries when the same object was registered multiple times. Use two-pointer compaction for O(N) removal. Fixes #6760. Co-authored-by: Claude <noreply@anthropic.com>	2026-03-25 15:29:27 +09:00
Yukihiro "Matz" Matsumoto	c2b588139f	Merge pull request #6758 from dearblue/vm	2026-03-25 15:17:02 +09:00
Yukihiro "Matz" Matsumoto	21dc829903	Merge pull request #6759 from dearblue/bigint	2026-03-25 15:15:49 +09:00
dearblue	6c4a8c09db	Define `mrb_bigint_p()` always. Define the `mrb_bigint_p()` macro function, which returns false if `MRB_USE_BIGINT` is undefined.	2026-03-24 22:16:15 +09:00
dearblue	c52faebb7f	Don't assign the result of `mrb_funcall()` directly to `regs` There are two reasons: - If the mruby call stack is extended, the `ci` variable may become invalid. - The C language does not specify the order in which the left-hand and right-hand sides of an assignment expression are evaluated. Therefore, if the mruby data stack is extended, `ci->stack` may become invalid.	2026-03-24 21:25:46 +09:00
Yukihiro "Matz" Matsumoto	f61ab96689	Merge pull request #6756 from dearblue/array-ext	2026-03-24 15:04:58 +09:00
Yukihiro "Matz" Matsumoto	07a6c6e56b	Merge pull request #6757 from mruby/dependabot/pre_commit/pre-commit-hooks-ae77450b09	2026-03-24 09:30:46 +09:00
dependabot[bot]	45ebb3d0c8	build(deps): bump https://github.com/rubocop/rubocop Bumps the pre-commit-hooks group with 1 update: [https://github.com/rubocop/rubocop](https://github.com/rubocop/rubocop). Updates `https://github.com/rubocop/rubocop` from v1.85.1 to 1.86.0 - [Release notes](https://github.com/rubocop/rubocop/releases) - [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md) - [Commits](https://github.com/rubocop/rubocop/compare/v1.85.1...v1.86.0) --- updated-dependencies: - dependency-name: https://github.com/rubocop/rubocop dependency-version: 1.86.0 dependency-type: direct:production dependency-group: pre-commit-hooks ... Signed-off-by: dependabot[bot] <support@github.com>	2026-03-23 15:23:09 +00:00
dearblue	2135088ada	Avoid the impact of object modifications caused by calls to `mrb_vm_exec()` Several methods defined in mruby-array-ext are written in C and may call `mrb_vm_exec()`. If array objects are modified on the Ruby side, problems may arise in subsequent processing. - Using objects that have been removed from the array and garbage collected - Using pointers or array lengths that have become invalid due to changes to the array object - Modifying the contents of a shared array object directly ref: https://github.com/mruby/mruby/issues/6662	2026-03-22 23:05:37 +09:00
Yukihiro "Matz" Matsumoto	04f998238e	Merge pull request #6755 from leviongit/vm/karg/delete-return	2026-03-21 17:03:27 +09:00
Yukihiro "Matz" Matsumoto	affcbb000b	Merge pull request #6754 from leviongit/core/attr_accessor/nullary	2026-03-21 17:02:24 +09:00
Yukihiro "Matz" Matsumoto	ff5e6a2491	Merge pull request #6753 from dearblue/array.product	2026-03-21 16:57:49 +09:00
leviongit	e8d0750458	reload `ci` after `mrb_hash_delete_key`	2026-03-20 21:35:26 +01:00
leviongit	88e356e7da	remove redundant `mrb_hash_get` call `mrb_hash_delete` returns the removed element (which is guaranteed to exist due to the `mrb_hash_key_p` check), this prevents the hash from being searched twice.	2026-03-20 21:20:18 +01:00
leviongit	95ece95e37	prefer marking the procs implementing `attr_reader` methods as noarg this commit works on #6752 so it doesn't require a call to `mrb_get_args`	2026-03-20 19:14:54 +01:00
dearblue	98d763603c	Further optimize `Array#product` Replace `__product_group` method with `__product_generate` and `__product_next`. This change eliminates the need for Ruby to perform internal state calculations, allowing it to simply receive the results.	2026-03-20 21:13:52 +09:00
Yukihiro "Matz" Matsumoto	01ce2f8c71	Merge pull request #6747 from katafrakt/handle-hash-default-arg	2026-03-20 16:44:27 +09:00
Yukihiro "Matz" Matsumoto	f08dede1d9	Merge pull request #6752 from khasinski/fix-attr-reader-arity	2026-03-20 16:40:45 +09:00
Yukihiro "Matz" Matsumoto	3bfe703f80	Merge pull request #6750 from dearblue/array.product	2026-03-20 10:24:10 +09:00
Yukihiro "Matz" Matsumoto	e82fa70004	Merge pull request #6749 from hasumikin/fix/microcontroller-profile	2026-03-20 10:22:32 +09:00
Yukihiro "Matz" Matsumoto	8d53f65b96	Merge pull request #6748 from jbampton/clean-up-workflows	2026-03-20 10:21:45 +09:00
Chris Hasiński	c0b1e87c09	Fix attr_reader-generated methods accepting extra arguments attr_reader-generated getter methods silently ignored any arguments passed to them. CRuby raises ArgumentError in this case. Add mrb_get_args(mrb, "") to enforce zero arguments, matching CRuby.	2026-03-19 23:12:14 +01:00
dearblue	8441eaf633	Fixed "Out-of-bounds Read" and "Divide-by-Zero" in `ary_product_group()` Reproduction: - Out-of-bounds Read ```console % build/host/bin/mruby -e '([nil] * 256).__product_group([[nil] * 256], 1 << 32, 256)' zsh: segmentation fault (core dumped) build/host/bin/mruby -e ``` - Divide-by-Zero ```console % build/host/bin/mruby -e '([nil] * 256).__product_group([[]], 1 << 32, 256)' zsh: floating point exception (core dumped) build/host/bin/mruby -e '([nil] * 256).__product_group([[]], 1 << 32, 256)' ```	2026-03-19 23:11:06 +09:00
HASUMI Hitoshi	736a72cdc9	[skip ci] Update include/mrbconf.h Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>	2026-03-19 09:50:15 +09:00
HASUMI Hitoshi	5e9eed2d0c	Fix KHASH_DEFAULT_SIZE to KHASH_INITIAL_SIZE rename inconsistencies Commit `250bf6edd` renamed KHASH_DEFAULT_SIZE to KHASH_INITIAL_SIZE but missed updating build_config files and documentation. Also restore the default value in khash.h to 32, consistent with the documented default and the profile hierarchy (MRB_CONSTRAINED_BASELINE_PROFILE reduces it to 16).	2026-03-19 09:38:36 +09:00
John Bampton	80d84188fd	pre-commit bump Node.js	2026-03-18 17:57:33 +10:00
John Bampton	55ef8e1728	Update workflows	2026-03-18 17:57:05 +10:00
Paweł Świątkowski	13d9d770fc	Correctly handle empty hash as default named argument ``` def func(arg: {}) p arg end ``` This used to work in earlier mruby versions, but broke somewhere recently.	2026-03-18 08:53:20 +01:00
Yukihiro "Matz" Matsumoto	a41eeaed33	Merge pull request #6735 from dearblue/presym	2026-03-16 21:55:22 +09:00
Yukihiro "Matz" Matsumoto	4ed4326dd5	Merge pull request #6746 from mruby/dependabot/pre_commit/pre-commit-hooks-6e50fbf5c1	2026-03-16 21:47:31 +09:00
dearblue	000acedc35	Prevent full recompilation without changes to presym file Commit `b9a1a1fb23` is a revert of commit `8df9a22a85`, differing only in the comment. This means the issue from https://github.com/mruby/mruby/issues/6721 has reappeared. The cause of https://github.com/mruby/mruby/issues/6721, as stated in the commit message for commit `8df9a22a85`, is that each ".o" file has an indirect dependency on all ".pi" files through the presym file. This patch therefore adds a proxy-like task `gensym:update:#{build.name}` between tasks. Its purpose is to hide the direct dependency from ".o" files to the presym file from the rake system.	2026-03-14 17:14:37 +09:00
dependabot[bot]	14e98c60c3	build(deps): bump the pre-commit-hooks group across 1 directory with 8 updates Bumps the pre-commit-hooks group with 8 updates in the / directory: \| Package \| From \| To \| \| --- \| --- \| --- \| \| [https://github.com/gitleaks/gitleaks](https://github.com/gitleaks/gitleaks) \| `v8.30.0` \| `8.30.1` \| \| [https://github.com/oxipng/oxipng](https://github.com/oxipng/oxipng) \| `v10.0.0` \| `10.1.0` \| \| [https://github.com/Lucas-C/pre-commit-hooks](https://github.com/Lucas-C/pre-commit-hooks) \| `v1.5.5` \| `1.5.6` \| \| [https://github.com/rhysd/actionlint](https://github.com/rhysd/actionlint) \| `v1.7.9` \| `1.7.11` \| \| [https://github.com/codespell-project/codespell](https://github.com/codespell-project/codespell) \| `v2.4.1` \| `2.4.2` \| \| [https://github.com/igorshubovych/markdownlint-cli](https://github.com/igorshubovych/markdownlint-cli) \| `v0.46.0` \| `0.48.0` \| \| [https://github.com/rubocop/rubocop](https://github.com/rubocop/rubocop) \| `v1.81.7` \| `1.85.1` \| \| [https://github.com/adrienverge/yamllint](https://github.com/adrienverge/yamllint) \| `v1.37.1` \| `1.38.0` \| Updates `https://github.com/gitleaks/gitleaks` from v8.30.0 to 8.30.1 - [Release notes](https://github.com/gitleaks/gitleaks/releases) - [Commits](https://github.com/gitleaks/gitleaks/compare/v8.30.0...v8.30.1) Updates `https://github.com/oxipng/oxipng` from v10.0.0 to 10.1.0 - [Release notes](https://github.com/oxipng/oxipng/releases) - [Changelog](https://github.com/oxipng/oxipng/blob/master/CHANGELOG.md) - [Commits](https://github.com/oxipng/oxipng/compare/v10.0.0...v10.1.0) Updates `https://github.com/Lucas-C/pre-commit-hooks` from v1.5.5 to 1.5.6 - [Release notes](https://github.com/Lucas-C/pre-commit-hooks/releases) - [Commits](https://github.com/Lucas-C/pre-commit-hooks/compare/v1.5.5...v1.5.6) Updates `https://github.com/rhysd/actionlint` from v1.7.9 to 1.7.11 - [Release notes](https://github.com/rhysd/actionlint/releases) - [Changelog](https://github.com/rhysd/actionlint/blob/main/CHANGELOG.md) - [Commits](https://github.com/rhysd/actionlint/compare/v1.7.9...v1.7.11) Updates `https://github.com/codespell-project/codespell` from v2.4.1 to 2.4.2 - [Release notes](https://github.com/codespell-project/codespell/releases) - [Commits](https://github.com/codespell-project/codespell/compare/v2.4.1...v2.4.2) Updates `https://github.com/igorshubovych/markdownlint-cli` from v0.46.0 to 0.48.0 - [Release notes](https://github.com/igorshubovych/markdownlint-cli/releases) - [Commits](https://github.com/igorshubovych/markdownlint-cli/compare/v0.46.0...v0.48.0) Updates `https://github.com/rubocop/rubocop` from v1.81.7 to 1.85.1 - [Release notes](https://github.com/rubocop/rubocop/releases) - [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md) - [Commits](https://github.com/rubocop/rubocop/compare/v1.81.7...v1.85.1) Updates `https://github.com/adrienverge/yamllint` from v1.37.1 to 1.38.0 - [Release notes](https://github.com/adrienverge/yamllint/releases) - [Changelog](https://github.com/adrienverge/yamllint/blob/master/CHANGELOG.rst) - [Commits](https://github.com/adrienverge/yamllint/compare/v1.37.1...v1.38.0) --- updated-dependencies: - dependency-name: https://github.com/gitleaks/gitleaks dependency-version: 8.30.1 dependency-type: direct:production dependency-group: pre-commit-hooks - dependency-name: https://github.com/oxipng/oxipng dependency-version: 10.1.0 dependency-type: direct:production dependency-group: pre-commit-hooks - dependency-name: https://github.com/Lucas-C/pre-commit-hooks dependency-version: 1.5.6 dependency-type: direct:production dependency-group: pre-commit-hooks - dependency-name: https://github.com/rhysd/actionlint dependency-version: 1.7.11 dependency-type: direct:production dependency-group: pre-commit-hooks - dependency-name: https://github.com/codespell-project/codespell dependency-version: 2.4.2 dependency-type: direct:production dependency-group: pre-commit-hooks - dependency-name: https://github.com/igorshubovych/markdownlint-cli dependency-version: 0.48.0 dependency-type: direct:production dependency-group: pre-commit-hooks - dependency-name: https://github.com/rubocop/rubocop dependency-version: 1.85.1 dependency-type: direct:production dependency-group: pre-commit-hooks - dependency-name: https://github.com/adrienverge/yamllint dependency-version: 1.38.0 dependency-type: direct:production dependency-group: pre-commit-hooks ... Signed-off-by: dependabot[bot] <support@github.com>	2026-03-13 14:57:23 +00:00