feat(ast): add AST creation methods to AST types by overlookmotel · Pull Request #23650 · oxc-project/oxc

overlookmotel · 2026-06-19T14:26:46Z

Part of #23043.

Codegen AST builder methods on AST types, matching the methods which are generated on current AstBuidler type.

Add a single new AstBuilder type which is the simplest possible - just creates all nodes with dummy NodeIds - same as current builder does. But this PR includes the traits to add other AstBuild implementations later e.g. a builder for transformer which generates unique NodeId for each AST node.

Design is much the same as outlined in #23043 but:

Extra trait to reduce trait bounds in generated methods (so reducing code size and compile time).
Different naming for enum methods - Expression::new_null_literal not Expression::null_literal. This naming is more verbose, but clearer, and avoids clashing with existing methods e.g. ModuleExportName::identifier_name.

Note: All these methods are inlined (they need to be, to make AST nodes be constructed in arena directly, not built on stack and copied to arena). So the traits should not have any affect on binary size.

overlookmotel · 2026-06-19T14:27:01Z

feat(ast): add custom builder methods to AST types #23651 : 2 dependent PRs (#23729 , #23730 )
feat(ast): add AST creation methods to AST types #23650 👈 (View in Graphite)
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codspeed-hq · 2026-06-19T14:33:53Z

Merging this PR will not alter performance

✅ 62 untouched benchmarks
⏩ 9 skipped benchmarks¹

_{Comparing om/06-06-feat_ast_add_ast_creation_methods_to_ast_types (f3b599f) with main (2580eda)}

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

Adds a new, feature-gated (“builder_new”) AST construction API where builder/factory methods are generated as inherent methods on AST node types (instead of being methods on the legacy AstBuilder). This is part of the longer-term AstBuilder redesign to support alternative builders (e.g. real NodeId generation) while keeping the current builder available for compatibility.

Changes:

Register a new BuilderMethodsGenerator in tasks/ast_tools to generate builder_methods.rs for AST types.
Add a new crates/oxc_ast::builder module (behind builder_new) defining AstBuild / GetAstBuilder traits plus a minimal AstBuilder that returns NodeId::DUMMY.
Wire the generated builder_methods module into oxc_ast behind the builder_new feature and add the feature flag to Cargo.toml.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tasks/ast_tools/src/main.rs	Registers the new generator in the ast_tools pipeline.
tasks/ast_tools/src/generators/mod.rs	Adds the new generator module/export.
tasks/ast_tools/src/generators/builder_methods.rs	Implements codegen for inherent AST-type builder methods (`new`, `boxed`, and `new_*` for enum variants).
crates/oxc_ast/src/lib.rs	Introduces feature-gated `builder` module + generated `builder_methods` module integration while keeping legacy `AstBuilder` re-export.
crates/oxc_ast/src/builder/mod.rs	Defines the new builder traits and minimal `AstBuilder` implementation (feature-gated via `lib.rs`).
crates/oxc_ast/Cargo.toml	Adds the `builder_new` cargo feature.

graphite-app · 2026-06-25T01:45:04Z

Merge activity

Jun 25, 1:45 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Jun 25, 1:52 AM UTC: Merged by the Graphite merge queue.

Part of #23043. Codegen AST builder methods on AST types, matching the methods which are generated on current `AstBuidler` type. Add a single new `AstBuilder` type which is the simplest possible - just creates all nodes with dummy `NodeId`s - same as current builder does. But this PR includes the traits to add other `AstBuild` implementations later e.g. a builder for transformer which generates unique `NodeId` for each AST node. Design is much the same as outlined in #23043 but: * Extra trait to reduce trait bounds in generated methods (so reducing code size and compile time). * Different naming for enum methods - `Expression::new_null_literal` not `Expression::null_literal`. This naming is more verbose, but clearer, and avoids clashing with existing methods e.g. `ModuleExportName::identifier_name`. Note: All these methods are inlined (they need to be, to make AST nodes be constructed in arena directly, not built on stack and copied to arena). So the traits should not have any affect on binary size.

### 💥 BREAKING CHANGES - 94fbacb ast: [**BREAKING**] Only export `AstBuilder` and `NONE` in `builder` module (#23876) (overlookmotel) - 8de5122 ecmascript: [**BREAKING**] Switch to new `AstBuilder` (#23834) (overlookmotel) - dc0ef38 transformer: [**BREAKING**] Switch to new `AstBuilder` (#23831) (overlookmotel) - 88f4455 str: [**BREAKING**] `Str` and `Ident` methods take `&GetAllocator` (#23781) (overlookmotel) - 36009dd allocator: [**BREAKING**] `GetAllocator::allocator` take `&self` (#23676) (overlookmotel) - bd74f9d allocator: [**BREAKING**] Rename `AllocatorAccessor` trait to `GetAllocator` (#23675) (overlookmotel) ### 🚀 Features - 326fe25 transformer_plugins: Support `typeof` `define` keys (#23605) (Alexander Lichter) - f2091b3 ast: Unify old and new `AstBuilder`s (#23875) (overlookmotel) - cd1fd12 codegen: Expose `Codegen::print_string` API (#23785) (camc314) - 785461b ast: Add custom builder methods to AST types (#23651) (overlookmotel) - 05d1357 ast: Add AST creation methods to AST types (#23650) (overlookmotel) - 2580eda str: Add `Str::from_str_in` and `Ident::from_str_in` methods (#23767) (overlookmotel) - 6883fcf minifier: Fold write-once falsy var to false in boolean context (#23540) (Dunqing) - fcbf993 allocator: Add `Vec::from_value_in` method (#23718) (overlookmotel) - 989ddb7 allocator: Add `Vec::from_box_in` method (#23717) (overlookmotel) - 9d1aa7f allocator: Improve `PartialEq` for `Vec` (#23716) (overlookmotel) ### 🐛 Bug Fixes - da0e5bf minifier: Don't reorder a closed-over TDZ read when inlining a var (#23771) (Dunqing) - 0b3021f allocator: Remove `Vec::from_box_in` (#23873) (overlookmotel) - 0ab64ec ast: Silence deprecation warnings within files defining deprecated `AstBuilder` methods (#23889) (overlookmotel) - 8c07cad all: Enable `disable_old_builder` Cargo feature for `oxc_ast` crate in tests (#23888) (overlookmotel) - 3800f01 ast: Legacy `AstBuilder` methods take `self` not `&self` (#23891) (overlookmotel) - 869ac20 semantic/cfg: Connect for update exit to loop test (#23791) (camc314) - d3e92d5 semantic/cfg: Connect while branches from condition exit (#23790) (camc314) - 025045d ast: `ExportNamedDeclaration` plain builder methods return boxed nodes (#23783) (overlookmotel) - 7537c58 ast: Fix name of `AstBuilder` method for `Expression::V8IntrinsicExpression` (#23766) (overlookmotel) - 3f574f5 traverse: Fix unsoundness in `Traverse` walk functions (#23745) (overlookmotel) - 585760f parser: String in AST reference arena (#23721) (overlookmotel) - 7231d55 allocator: Fix unsound lifetime extension in `Box::new_in` (#23685) (overlookmotel) ### ⚡ Performance - d5c916a semantic: Flatten hoisting_variables to avoid per-scope map allocation (#23927) (Lawrence Lin) - e71609d minifier: Bail member-expr folding before the side-effect walk (#23924) (Lawrence Lin) - e1f89ab minifier: Reduce string allocations folding addition (#23846) (overlookmotel) - 9f6ee3b isolated-declarations: Pool scope maps to avoid per-scope alloc/rehash (#23761) (Boshen) - 0b07c4c semantic: Avoid heap alloc for catch-clause binding ids (#23911) (Lawrence Lin) - c5eef8b regular_expression: Skip capturing-group pre-parse when pattern has no `(` (#23908) (Lawrence Lin) - b4f5b4b isolated_declarations: Remove redundant clone of formal parameter pattern (#23912) (Lawrence Lin) - 53d083f isolated_declarations: Use `TakeIn` not `CloneIn` (#23847) (overlookmotel) - 3ea9304 react_compiler: Use faster API to arena allocate strings (#23849) (overlookmotel) - a6d8e45 parser: Avoid span lookup for arrow expression body (#23788) (camc314) - e1886a0 transformer, minifier: Use `static_ident!` macro to create static `Ident`s (#23727) (overlookmotel) - 5527bef transformer/object-rest-spread: Reduce iteration (#23720) (overlookmotel) - 680ffbc transformer: Allocate AST nodes in arena directly (#23711) (overlookmotel) - 1c63c66 parser: Allocate AST nodes in arena directly (#23712) (overlookmotel) - 3855f0c minifier: Allocate AST nodes in arena directly (#23710) (overlookmotel) - d025887 isolated_declarations: Allocate AST nodes in arena directly (#23709) (overlookmotel) - 10b96c6 parser: Remove string search from parsing JSX element name (#23713) (overlookmotel) ### 📚 Documentation - 3d61dea all: Correct capitalization in comments (#23887) (overlookmotel) - aa1ad74 ast: Add `#[deprecated]` to legacy `AstBuilder` methods (#23877) (overlookmotel) - a4676db ast: Correct doc comment for `NONE` (#23765) (overlookmotel) - 419ec80 syntax: Fix typo in doc comment (#23674) (overlookmotel) ### 🛡️ Security - 3cdd18f deps: Update npm packages (#23690) (renovate[bot]) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com> Co-authored-by: Cameron <cameron.clark@hey.com>

Part of #23043. Codegen AST builder methods on AST types, matching the methods which are generated on current `AstBuidler` type. Add a single new `AstBuilder` type which is the simplest possible - just creates all nodes with dummy `NodeId`s - same as current builder does. But this PR includes the traits to add other `AstBuild` implementations later e.g. a builder for transformer which generates unique `NodeId` for each AST node. Design is much the same as outlined in #23043 but: * Extra trait to reduce trait bounds in generated methods (so reducing code size and compile time). * Different naming for enum methods - `Expression::new_null_literal` not `Expression::null_literal`. This naming is more verbose, but clearer, and avoids clashing with existing methods e.g. `ModuleExportName::identifier_name`. Note: All these methods are inlined (they need to be, to make AST nodes be constructed in arena directly, not built on stack and copied to arena). So the traits should not have any affect on binary size.

### 💥 BREAKING CHANGES - 94fbacb ast: [**BREAKING**] Only export `AstBuilder` and `NONE` in `builder` module (#23876) (overlookmotel) - 8de5122 ecmascript: [**BREAKING**] Switch to new `AstBuilder` (#23834) (overlookmotel) - dc0ef38 transformer: [**BREAKING**] Switch to new `AstBuilder` (#23831) (overlookmotel) - 88f4455 str: [**BREAKING**] `Str` and `Ident` methods take `&GetAllocator` (#23781) (overlookmotel) - 36009dd allocator: [**BREAKING**] `GetAllocator::allocator` take `&self` (#23676) (overlookmotel) - bd74f9d allocator: [**BREAKING**] Rename `AllocatorAccessor` trait to `GetAllocator` (#23675) (overlookmotel) ### 🚀 Features - 326fe25 transformer_plugins: Support `typeof` `define` keys (#23605) (Alexander Lichter) - f2091b3 ast: Unify old and new `AstBuilder`s (#23875) (overlookmotel) - cd1fd12 codegen: Expose `Codegen::print_string` API (#23785) (camc314) - 785461b ast: Add custom builder methods to AST types (#23651) (overlookmotel) - 05d1357 ast: Add AST creation methods to AST types (#23650) (overlookmotel) - 2580eda str: Add `Str::from_str_in` and `Ident::from_str_in` methods (#23767) (overlookmotel) - 6883fcf minifier: Fold write-once falsy var to false in boolean context (#23540) (Dunqing) - fcbf993 allocator: Add `Vec::from_value_in` method (#23718) (overlookmotel) - 989ddb7 allocator: Add `Vec::from_box_in` method (#23717) (overlookmotel) - 9d1aa7f allocator: Improve `PartialEq` for `Vec` (#23716) (overlookmotel) ### 🐛 Bug Fixes - da0e5bf minifier: Don't reorder a closed-over TDZ read when inlining a var (#23771) (Dunqing) - 0b3021f allocator: Remove `Vec::from_box_in` (#23873) (overlookmotel) - 0ab64ec ast: Silence deprecation warnings within files defining deprecated `AstBuilder` methods (#23889) (overlookmotel) - 8c07cad all: Enable `disable_old_builder` Cargo feature for `oxc_ast` crate in tests (#23888) (overlookmotel) - 3800f01 ast: Legacy `AstBuilder` methods take `self` not `&self` (#23891) (overlookmotel) - 869ac20 semantic/cfg: Connect for update exit to loop test (#23791) (camc314) - d3e92d5 semantic/cfg: Connect while branches from condition exit (#23790) (camc314) - 025045d ast: `ExportNamedDeclaration` plain builder methods return boxed nodes (#23783) (overlookmotel) - 7537c58 ast: Fix name of `AstBuilder` method for `Expression::V8IntrinsicExpression` (#23766) (overlookmotel) - 3f574f5 traverse: Fix unsoundness in `Traverse` walk functions (#23745) (overlookmotel) - 585760f parser: String in AST reference arena (#23721) (overlookmotel) - 7231d55 allocator: Fix unsound lifetime extension in `Box::new_in` (#23685) (overlookmotel) ### ⚡ Performance - d5c916a semantic: Flatten hoisting_variables to avoid per-scope map allocation (#23927) (Lawrence Lin) - e71609d minifier: Bail member-expr folding before the side-effect walk (#23924) (Lawrence Lin) - e1f89ab minifier: Reduce string allocations folding addition (#23846) (overlookmotel) - 9f6ee3b isolated-declarations: Pool scope maps to avoid per-scope alloc/rehash (#23761) (Boshen) - 0b07c4c semantic: Avoid heap alloc for catch-clause binding ids (#23911) (Lawrence Lin) - c5eef8b regular_expression: Skip capturing-group pre-parse when pattern has no `(` (#23908) (Lawrence Lin) - b4f5b4b isolated_declarations: Remove redundant clone of formal parameter pattern (#23912) (Lawrence Lin) - 53d083f isolated_declarations: Use `TakeIn` not `CloneIn` (#23847) (overlookmotel) - 3ea9304 react_compiler: Use faster API to arena allocate strings (#23849) (overlookmotel) - a6d8e45 parser: Avoid span lookup for arrow expression body (#23788) (camc314) - e1886a0 transformer, minifier: Use `static_ident!` macro to create static `Ident`s (#23727) (overlookmotel) - 5527bef transformer/object-rest-spread: Reduce iteration (#23720) (overlookmotel) - 680ffbc transformer: Allocate AST nodes in arena directly (#23711) (overlookmotel) - 1c63c66 parser: Allocate AST nodes in arena directly (#23712) (overlookmotel) - 3855f0c minifier: Allocate AST nodes in arena directly (#23710) (overlookmotel) - d025887 isolated_declarations: Allocate AST nodes in arena directly (#23709) (overlookmotel) - 10b96c6 parser: Remove string search from parsing JSX element name (#23713) (overlookmotel) ### 📚 Documentation - 3d61dea all: Correct capitalization in comments (#23887) (overlookmotel) - aa1ad74 ast: Add `#[deprecated]` to legacy `AstBuilder` methods (#23877) (overlookmotel) - a4676db ast: Correct doc comment for `NONE` (#23765) (overlookmotel) - 419ec80 syntax: Fix typo in doc comment (#23674) (overlookmotel) ### 🛡️ Security - 3cdd18f deps: Update npm packages (#23690) (renovate[bot]) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com> Co-authored-by: Cameron <cameron.clark@hey.com>

This was referenced Jun 19, 2026

refactor(ast): add ast_builder Cargo feature #23649

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feat(ast): add custom builder methods to AST types #23651

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github-actions Bot added A-ast Area - AST A-ast-tools Area - AST tools labels Jun 19, 2026

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feat(ast)!: put AstBuilder behind builder Cargo feature #23739

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refactor(ast): add builder Cargo feature #23743

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