refactor(all): import arena `Box` and `Vec` as `ArenaBox` / `ArenaVec` by overlookmotel · Pull Request #23747 · oxc-project/oxc

overlookmotel · 2026-06-23T20:00:56Z

Pure refactor.

Use ArenaBox and ArenaVec everywhere for the arena-allocated types from oxc_allocator, instead of plain Box and Vec.

This disambiguates when Vec is oxc_allocator::Vec and when it's std::vec::Vec, making code clearer to follow.

Previously it was easy to confuse the two, and such confusion led to UB in Traverse (fixed in #23745).

Ditto other arena types - ArenaHashMap, ArenaHashSet, ArenaStringBuilder.

The only exceptions are:

Inside oxc_allocator crate itself.
AST type definitions.
Generated code (migrated separately in refactor(all): use ArenaBox and ArenaVec in generated code #23749).

overlookmotel · 2026-06-23T20:01:11Z

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codspeed-hq · 2026-06-23T20:09:47Z

Merging this PR will not alter performance

✅ 62 untouched benchmarks
⏩ 9 skipped benchmarks¹

_{Comparing om/06-23-refactor_all_import_arena_box_and_vec_as_arenabox___arenavec_ (2ea7dcc) with om/06-23-refactor_allocator_export_arenabox_and_arenavec_aliases (3f1e6c5)}

9 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

Copilot

Pull request overview

Refactors the codebase to consistently use oxc_allocator’s arena-allocated type aliases (ArenaBox, ArenaVec, ArenaHashMap, ArenaHashSet, ArenaStringBuilder, etc.) instead of importing/using plain Box/Vec/HashMap/HashSet directly, improving clarity about which collections are arena-backed.

Changes:

Updated imports and type annotations across many crates to prefer Arena* aliases for arena-allocated types.
Adjusted function signatures/return types and a few docs/comments to reflect the renamed arena types.
Updated several formatter/linter/parser implementations to use ArenaStringBuilder / ArenaVec consistently.

Reviewed changes

Copilot reviewed 101 out of 101 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tasks/rulegen/src/main.rs	Switches parsed argument vec types to `ArenaVec` and updates imports accordingly.
tasks/ast_tools/src/parse/parse.rs	Allows parsing type names `ArenaBox`/`ArenaVec` as arena `Box`/`Vec` equivalents.
napi/parser/src/raw_transfer_types.rs	Migrates transfer structs/helpers from allocator `Vec` to `ArenaVec`.
crates/oxc_traverse/src/context/scoping.rs	Updates scope insertion API to take `&ArenaVec<'a, Statement<'a>>`.
crates/oxc_traverse/src/context/mod.rs	Updates `TraverseCtx` arena allocation docs and `ArenaVec` statement APIs.
crates/oxc_transformer/src/jsx/jsx_impl.rs	Fixes JSX transform API to accept `ArenaVec<'a, JSXChild<'a>>`.
crates/oxc_transformer_plugins/src/replace_global_defines.rs	Uses `ArenaBox` in imports and parameter types.
crates/oxc_syntax/src/module_record.rs	Migrates module record containers to `ArenaHashMap`/`ArenaVec`.
crates/oxc_str/src/ident.rs	Updates arena ident map alias to `ArenaHashMap`.
crates/oxc_span/src/cmp.rs	Uses `ArenaBox`/`ArenaVec` for `ContentEq` blanket impls and imports.
crates/oxc_semantic/src/builder.rs	Migrates decorator vec references to `ArenaVec`.
crates/oxc_regular_expression/src/parser/pattern_parser/pattern_parser_impl.rs	Migrates regex parser allocations to `ArenaBox`/`ArenaVec`.
crates/oxc_regular_expression/src/ast.rs	Updates regex AST node storage to `ArenaBox`/`ArenaVec`.
crates/oxc_react_compiler/src/lib.rs	Uses `ArenaVec` for preserved comments buffer.
crates/oxc_react_compiler/src/convert_ast_reverse.rs	Switches builder output vectors/boxes and string building to arena aliases.
crates/oxc_parser/src/ts/types.rs	Migrates TS type parsing APIs to `ArenaBox`/`ArenaVec`.
crates/oxc_parser/src/ts/statement.rs	Migrates TS statement parsing APIs to `ArenaBox`/`ArenaVec`.
crates/oxc_parser/src/module_record.rs	Uses `ArenaVec` inside the module record builder.
crates/oxc_parser/src/lib.rs	Updates parser return/token storage and statement reparsing APIs to `ArenaVec`.
crates/oxc_parser/src/lexer/unicode.rs	Switches lexer string building to `ArenaStringBuilder`.
crates/oxc_parser/src/lexer/template.rs	Switches template literal building to `ArenaStringBuilder`.
crates/oxc_parser/src/lexer/string.rs	Switches string literal building to `ArenaStringBuilder`.
crates/oxc_parser/src/lexer/identifier.rs	Switches identifier escape building to `ArenaStringBuilder`.
crates/oxc_parser/src/jsx/mod.rs	Migrates JSX parsing allocations and child vectors to arena aliases.
crates/oxc_parser/src/js/statement.rs	Migrates statement parsing allocations to `ArenaBox`/`ArenaVec`.
crates/oxc_parser/src/js/object.rs	Migrates object parsing allocations to `ArenaBox`.
crates/oxc_parser/src/js/module.rs	Migrates module parsing allocations/specifier vectors to `ArenaVec`/`ArenaBox`.
crates/oxc_parser/src/js/function.rs	Migrates function parsing allocations/parameter lists to arena aliases.
crates/oxc_parser/src/js/expression.rs	Migrates expression parsing allocations/argument vectors to arena aliases.
crates/oxc_parser/src/js/declaration.rs	Migrates variable declaration parsing allocations to `ArenaBox`.
crates/oxc_parser/src/js/class.rs	Migrates class parsing allocations and implements/extends vectors to arena aliases.
crates/oxc_parser/src/js/binding.rs	Migrates binding pattern parsing allocations to `ArenaBox`.
crates/oxc_parser/src/js/arrow.rs	Migrates arrow head types to `ArenaBox`.
crates/oxc_parser/src/cursor.rs	Migrates list parsing helpers to return/accept `ArenaVec` and arena boxes.
crates/oxc_minifier/src/traverse_context/scoping.rs	Updates scope insertion API to take `&ArenaVec<'a, Statement<'a>>`.
crates/oxc_minifier/src/traverse_context/mod.rs	Updates `TraverseCtx` docs and `ArenaVec` statement APIs.
crates/oxc_minifier/src/peephole/substitute_alternate_syntax.rs	Uses `ArenaVec` for peephole argument lists.
crates/oxc_minifier/src/peephole/replace_known_methods.rs	Uses `ArenaVec` alias for arguments and `ArenaBox` for regex pattern storage.
crates/oxc_minifier/src/peephole/remove_unused_expression.rs	Uses `ArenaVec` for argument folding outputs and return types.
crates/oxc_minifier/src/peephole/remove_dead_code.rs	Uses `ArenaVec` for spread-argument removal API.
crates/oxc_minifier/src/peephole/normalize.rs	Uses `ArenaVec` for statement lists in traversal hook.
crates/oxc_minifier/src/peephole/mod.rs	Uses `ArenaVec` throughout peephole traversal entrypoints.
crates/oxc_minifier/src/peephole/minimize_statements.rs	Migrates peephole minimization buffers and statement vecs to arena aliases.
crates/oxc_mangler/src/lib.rs	Migrates mangler’s temp arena collections to `ArenaVec`/`ArenaHashSet`.
crates/oxc_linter/src/utils/jest/parse_jest_fn.rs	Uses `ArenaVec` references for AST argument lists.
crates/oxc_linter/src/rules/vitest/prefer_called_exactly_once_with.rs	Migrates block statement vec references to `ArenaVec`.
crates/oxc_linter/src/rules/unicorn/require_module_attributes.rs	Migrates object property vec references to `ArenaVec`.
crates/oxc_linter/src/rules/unicorn/no_unreadable_array_destructuring.rs	Migrates array destructuring element vec type to `ArenaVec`.
crates/oxc_linter/src/rules/unicorn/no_invalid_fetch_options.rs	Migrates object expression box type to `ArenaBox`.
crates/oxc_linter/src/rules/typescript/prefer_function_type.rs	Simplifies body binding while relying on `ArenaVec` typing.
crates/oxc_linter/src/rules/typescript/no_inferrable_types.rs	Migrates parameter vec references to `ArenaVec`.
crates/oxc_linter/src/rules/typescript/explicit_module_boundary_types.rs	Migrates statement vec references to `ArenaVec`.
crates/oxc_linter/src/rules/typescript/consistent_generic_constructors.rs	Migrates type annotation box reference to `ArenaBox`.
crates/oxc_linter/src/rules/shared/jest_vitest/valid_expect_in_promise.rs	Migrates statement/argument vec references to `ArenaVec`.
crates/oxc_linter/src/rules/shared/jest_vitest/require_hook.rs	Migrates statement vec references to `ArenaVec`.
crates/oxc_linter/src/rules/shared/jest_vitest/no_test_return_statement.rs	Migrates function body box reference to `ArenaBox`.
crates/oxc_linter/src/rules/react/no_danger_with_children.rs	Migrates object property vec references to `ArenaVec`.
crates/oxc_linter/src/rules/react/jsx_no_useless_fragment.rs	Migrates JSX children vec references to `ArenaVec`.
crates/oxc_linter/src/rules/react/jsx_curly_brace_presence.rs	Migrates JSX children vec references to `ArenaVec`.
crates/oxc_linter/src/rules/react/exhaustive_deps.rs	Uses `ArenaVec` when constructing dependency arrays in fixes.
crates/oxc_linter/src/rules/promise/no_return_in_finally.rs	Migrates function body box reference to `ArenaBox`.
crates/oxc_linter/src/rules/oxc/no_map_spread.rs	Updates safety comment to refer to `ArenaBox`.
crates/oxc_linter/src/rules/import/consistent_type_specifier_style.rs	Uses `ArenaVec` to build new import specifier lists.
crates/oxc_linter/src/rules/eslint/require_unicode_regexp.rs	Migrates argument vec type to `ArenaVec`.
crates/oxc_linter/src/rules/eslint/prefer_object_spread.rs	Migrates object expression box type to `ArenaBox`.
crates/oxc_linter/src/rules/eslint/no_useless_return.rs	Migrates statement vec reference type to `ArenaVec`.
crates/oxc_linter/src/rules/eslint/no_regex_spaces.rs	Migrates argument vec reference type to `ArenaVec`.
crates/oxc_linter/src/rules/eslint/no_obj_calls.rs	Migrates identifier reference box type to `ArenaBox`.
crates/oxc_linter/src/rules/eslint/grouped_accessor_pairs.rs	Updates map value types to use `ArenaBox` with explicit lifetimes.
crates/oxc_linter/src/rules/eslint/array_callback_return/return_checker.rs	Migrates statement vec reference to `ArenaVec`.
crates/oxc_linter/src/ast_util.rs	Migrates regex flag extractor to accept `ArenaVec`.
crates/oxc_formatter/src/print/variable_declaration.rs	Migrates `AstNode<Vec<...>>` formatting impl to `ArenaVec`.
crates/oxc_formatter/src/print/union_type.rs	Migrates union list formatting to `ArenaVec` and updates comment.
crates/oxc_formatter/src/print/type_parameters.rs	Migrates type parameter list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/tuple_type.rs	Migrates tuple element list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/template/mod.rs	Migrates template printing string building to `ArenaStringBuilder`.
crates/oxc_formatter/src/print/template/embed/markdown.rs	Migrates markdown embed string building to `ArenaStringBuilder`.
crates/oxc_formatter/src/print/template/embed/html.rs	Migrates html embed string building to `ArenaStringBuilder`.
crates/oxc_formatter/src/print/template/embed/css.rs	Migrates css embed string building to `ArenaStringBuilder`.
crates/oxc_formatter/src/print/switch_statement.rs	Migrates switch case list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/program.rs	Migrates program directive/statement list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/mod.rs	Migrates multiple list-formatting impls to `ArenaVec`.
crates/oxc_formatter/src/print/jsx/mod.rs	Migrates JSX attribute list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/jsx/element.rs	Migrates JSX children list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/intersection_type.rs	Migrates intersection list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/import_declaration.rs	Migrates import specifier/attribute list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/export_declarations.rs	Migrates export specifier list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/decorators.rs	Migrates decorator list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/class.rs	Migrates class element/implements/etc formatting to `ArenaVec`.
crates/oxc_formatter/src/print/call_like_expression/arguments.rs	Migrates call argument list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/block_statement.rs	Migrates block statement list formatting to `ArenaVec`.
crates/oxc_formatter/src/print/binding_property_list.rs	Migrates binding property list node types to `ArenaVec`.
crates/oxc_formatter/src/print/assignment_pattern_property_list.rs	Migrates assignment target property list node types to `ArenaVec`.
crates/oxc_formatter/src/print/array_element_list.rs	Migrates array element list node types to `ArenaVec`.
crates/oxc_formatter/src/formatter/trivia.rs	Migrates trivia/comment normalization to `ArenaStringBuilder`.
crates/oxc_formatter/src/ast_nodes/node.rs	Migrates import-expression argument synthesis vec to `ArenaVec`.
crates/oxc_formatter/src/ast_nodes/iterator.rs	Migrates `AstNode<Vec<...>>` iterator impls to `AstNode<ArenaVec<...>>`.
crates/oxc_formatter_json/src/comments.rs	Migrates JSON comment normalization to `ArenaStringBuilder`.
crates/oxc_ecmascript/src/constant_evaluation/call_expr.rs	Migrates constant-eval helpers to accept `ArenaVec` argument lists.
crates/oxc_ast/src/ast_builder_impl.rs	Migrates `AstBuilder` APIs to return `ArenaBox`/`ArenaVec`.
apps/oxfmt/src/prettier_compat/from_prettier_doc.rs	Migrates doc conversion string building to `ArenaStringBuilder`.

graphite-app · 2026-06-24T01:20:51Z

Merge activity

Jun 24, 1:20 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Jun 24, 1:27 AM UTC: Merged by the Graphite merge queue.

#23747) Pure refactor. Use `ArenaBox` and `ArenaVec` everywhere for the arena-allocated types from `oxc_allocator`, instead of plain `Box` and `Vec`. This disambiguates when `Vec` is `oxc_allocator::Vec` and when it's `std::vec::Vec`, making code clearer to follow. Previously it was easy to confuse the two, and such confusion led to UB in `Traverse` (fixed in #23745). Ditto other arena types - `ArenaHashMap`, `ArenaHashSet`, `ArenaStringBuilder`. The only exceptions are: 1. Inside `oxc_allocator` crate itself. 2. AST type definitions. 3. Generated code (migrated separately in #23749).

Pure refactor. #23747 changed all usage of `Vec` and `Box` to `ArenaVec` / `ArenaBox` in hand-written code. Do the same for generated code.

#23747) Pure refactor. Use `ArenaBox` and `ArenaVec` everywhere for the arena-allocated types from `oxc_allocator`, instead of plain `Box` and `Vec`. This disambiguates when `Vec` is `oxc_allocator::Vec` and when it's `std::vec::Vec`, making code clearer to follow. Previously it was easy to confuse the two, and such confusion led to UB in `Traverse` (fixed in #23745). Ditto other arena types - `ArenaHashMap`, `ArenaHashSet`, `ArenaStringBuilder`. The only exceptions are: 1. Inside `oxc_allocator` crate itself. 2. AST type definitions. 3. Generated code (migrated separately in #23749).

Pure refactor. #23747 changed all usage of `Vec` and `Box` to `ArenaVec` / `ArenaBox` in hand-written code. Do the same for generated code.

This was referenced Jun 23, 2026

refactor(allocator): export ArenaBox and ArenaVec aliases #23746

Merged

refactor(all): shorten redundant std::vec::Vec #23748

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refactor(all): use ArenaBox and ArenaVec in generated code #23749

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github-actions Bot added A-linter Area - Linter A-parser Area - Parser A-semantic Area - Semantic A-cli Area - CLI A-minifier Area - Minifier A-ast Area - AST A-transformer Area - Transformer / Transpiler A-ast-tools Area - AST tools A-formatter Area - Formatter labels Jun 23, 2026

overlookmotel marked this pull request as ready for review June 23, 2026 20:09

overlookmotel requested review from Dunqing, camc314 and leaysgur as code owners June 23, 2026 20:09

Copilot AI review requested due to automatic review settings June 23, 2026 20:09

Copilot started reviewing on behalf of overlookmotel June 23, 2026 20:09 View session

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Comment thread crates/oxc_formatter/src/print/call_like_expression/arguments.rs Outdated

Comment thread crates/oxc_traverse/src/context/mod.rs Outdated

Comment thread crates/oxc_minifier/src/traverse_context/mod.rs Outdated

Comment thread crates/oxc_span/src/cmp.rs Outdated

overlookmotel force-pushed the om/06-23-refactor_all_import_arena_box_and_vec_as_arenabox___arenavec_ branch from 4b2595a to 2ea7dcc Compare June 23, 2026 20:30

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graphite-app Bot force-pushed the om/06-23-refactor_allocator_export_arenabox_and_arenavec_aliases branch from 3f1e6c5 to 8c6481b Compare June 24, 2026 01:21

graphite-app Bot force-pushed the om/06-23-refactor_all_import_arena_box_and_vec_as_arenabox___arenavec_ branch from 2ea7dcc to d1f18cd Compare June 24, 2026 01:22

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camc314 pushed a commit that referenced this pull request Jul 3, 2026

refactor(all): use ArenaBox and ArenaVec in generated code (#23749)

6d4a7c8

Pure refactor. #23747 changed all usage of `Vec` and `Box` to `ArenaVec` / `ArenaBox` in hand-written code. Do the same for generated code.

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refactor(all): import arena `Box` and `Vec` as `ArenaBox` / `ArenaVec`#23747

refactor(all): import arena `Box` and `Vec` as `ArenaBox` / `ArenaVec`#23747
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