refactor(ast): remove `inherit_variants!` macro by overlookmotel · Pull Request #23960 · oxc-project/oxc

overlookmotel · 2026-06-30T00:00:32Z

Remove the inherit_variants! macro from oxc_ast.

Before:

inherit_variants! {
    #[ast]
    pub enum Expression<'a> {
        // ... own variants ...
        INHERIT(MemberExpression<'a>),
    }
}

After:

#[ast]
pub enum Expression<'a> {
    // ... own variants ...
    INHERIT(MemberExpression<'a>),
}

The way it works now is that ast_tools generates the data the #[ast] macro needs to add the inherited enum variants, and #[ast] macro uses that data to add the variants (from MemberExpression, in this case).

This has a few advantages:

Wrapping enums in inherit_variants! { ... } was ugly. Now it's gone.
inherit_variants! macro no longer needs to be maintained by hand. Changes to AST will now be reflected automatically.
Inherited variants are auto-generated, so it's now statically guaranteed by codegen that variants' "payloads" and discriminants match between the inheriting and inherited enums, so we can remove 2000 lines of const assertions which checked this.
Better IDE experience. "Jump to definition" on MemberExpression in INHERIT(MemberExpression<'a>) now jumps to MemberExpression's definition.

Only changes the means by which enum inheritance is implemented, does not change how it operates.

overlookmotel · 2026-06-30T00:00:57Z

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codspeed-hq · 2026-06-30T00:12:09Z

Merging this PR will not alter performance

✅ 62 untouched benchmarks
⏩ 9 skipped benchmarks¹

_{Comparing om/06-29-refactor_ast_remove_inherit_variants_macro (be17950) with main (e94b6cd)²}

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. ↩
No successful run was found on main (37cbf88) during the generation of this report, so e94b6cd was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

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overlookmotel · 2026-06-30T10:30:00Z

@claude review

graphite-app · 2026-06-30T13:04:20Z

Merge activity

Jun 30, 1:04 PM UTC: overlookmotel added this pull request to the Graphite merge queue.
Jun 30, 1:14 PM UTC: The Graphite merge queue removed this pull request due to downstack failures on PR #23948.
Jun 30, 1:14 PM UTC: The Graphite merge queue removed this pull request due to downstack failures on PR #23948.
Jun 30, 4:20 PM UTC: overlookmotel added this pull request to the Graphite merge queue.
Jun 30, 4:43 PM UTC: Merged by the Graphite merge queue.

@inherit

Change the syntax used to declare that one enum inherits the variants from another. Before: ```rust enum Expression<'a> { // ... own variants ... @inherit MemberExpression } ``` After: ```rust enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } ``` Reason for this change is that the latter is valid Rust code, and can be parsed normally by Rust compiler and `syn`. This removes the need for custom parsing logic in `ast_tools` - now we can just use `syn`'s standard parser for enums. The downside it that this complicates the `inherit_variants!` macro - this PR reimplements it as a TT-muncher. But this macro is removed entirely in a later PR (#23960). No change to behavior - only affects _how_ inheritance is declared, not how it works.

Remove the `inherit_variants!` macro from `oxc_ast`. Before: ```rust inherit_variants! { #[ast] pub enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } } ``` After: ```rust #[ast] pub enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } ``` The way it works now is that `ast_tools` generates the data the `#[ast]` macro needs to add the inherited enum variants, and `#[ast]` macro uses that data to add the variants (from `MemberExpression`, in this case). This has a few advantages: - Wrapping enums in `inherit_variants! { ... }` was ugly. Now it's gone. - `inherit_variants!` macro no longer needs to be maintained by hand. Changes to AST will now be reflected automatically. - Inherited variants are auto-generated, so it's now statically guaranteed by codegen that variants' "payloads" and discriminants match between the inheriting and inherited enums, so we can remove 2000 lines of const assertions which checked this. - Better IDE experience. "Jump to definition" on `MemberExpression` in `INHERIT(MemberExpression<'a>)` now jumps to `MemberExpression`'s definition. Only changes the _means_ by which enum inheritance is implemented, does not change how it operates.

camc314 · 2026-06-30T14:08:25Z

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Remove the `inherit_variants!` macro from `oxc_ast`. Before: ```rust inherit_variants! { #[ast] pub enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } } ``` After: ```rust #[ast] pub enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } ``` The way it works now is that `ast_tools` generates the data the `#[ast]` macro needs to add the inherited enum variants, and `#[ast]` macro uses that data to add the variants (from `MemberExpression`, in this case). This has a few advantages: - Wrapping enums in `inherit_variants! { ... }` was ugly. Now it's gone. - `inherit_variants!` macro no longer needs to be maintained by hand. Changes to AST will now be reflected automatically. - Inherited variants are auto-generated, so it's now statically guaranteed by codegen that variants' "payloads" and discriminants match between the inheriting and inherited enums, so we can remove 2000 lines of const assertions which checked this. - Better IDE experience. "Jump to definition" on `MemberExpression` in `INHERIT(MemberExpression<'a>)` now jumps to `MemberExpression`'s definition. Only changes the _means_ by which enum inheritance is implemented, does not change how it operates.

@inherit

…3953) Change the syntax used to declare that one enum inherits the variants from another. Before: ```rust enum Expression<'a> { // ... own variants ... @inherit MemberExpression } ``` After: ```rust enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } ``` Reason for this change is that the latter is valid Rust code, and can be parsed normally by Rust compiler and `syn`. This removes the need for custom parsing logic in `ast_tools` - now we can just use `syn`'s standard parser for enums. The downside it that this complicates the `inherit_variants!` macro - this PR reimplements it as a TT-muncher. But this macro is removed entirely in a later PR (oxc-project#23960). No change to behavior - only affects _how_ inheritance is declared, not how it works.

@inherit

Change the syntax used to declare that one enum inherits the variants from another. Before: ```rust enum Expression<'a> { // ... own variants ... @inherit MemberExpression } ``` After: ```rust enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } ``` Reason for this change is that the latter is valid Rust code, and can be parsed normally by Rust compiler and `syn`. This removes the need for custom parsing logic in `ast_tools` - now we can just use `syn`'s standard parser for enums. The downside it that this complicates the `inherit_variants!` macro - this PR reimplements it as a TT-muncher. But this macro is removed entirely in a later PR (#23960). No change to behavior - only affects _how_ inheritance is declared, not how it works.

Remove the `inherit_variants!` macro from `oxc_ast`. Before: ```rust inherit_variants! { #[ast] pub enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } } ``` After: ```rust #[ast] pub enum Expression<'a> { // ... own variants ... INHERIT(MemberExpression<'a>), } ``` The way it works now is that `ast_tools` generates the data the `#[ast]` macro needs to add the inherited enum variants, and `#[ast]` macro uses that data to add the variants (from `MemberExpression`, in this case). This has a few advantages: - Wrapping enums in `inherit_variants! { ... }` was ugly. Now it's gone. - `inherit_variants!` macro no longer needs to be maintained by hand. Changes to AST will now be reflected automatically. - Inherited variants are auto-generated, so it's now statically guaranteed by codegen that variants' "payloads" and discriminants match between the inheriting and inherited enums, so we can remove 2000 lines of const assertions which checked this. - Better IDE experience. "Jump to definition" on `MemberExpression` in `INHERIT(MemberExpression<'a>)` now jumps to `MemberExpression`'s definition. Only changes the _means_ by which enum inheritance is implemented, does not change how it operates.

This was referenced Jun 30, 2026

feat(ast): add method to widen inherited enum ref to parent ref #23961

Merged

refactor(ast): enum conversion methods use NonNull #23962

Merged

github-actions Bot added A-ast Area - AST A-ast-tools Area - AST tools labels Jun 30, 2026

overlookmotel force-pushed the om/06-29-refactor_ast_remove_inherit_variants_macro branch from fb873ae to 36bf6df Compare June 30, 2026 00:34

overlookmotel self-assigned this Jun 30, 2026

overlookmotel marked this pull request as ready for review June 30, 2026 10:09

Copilot AI review requested due to automatic review settings June 30, 2026 10:09

Copilot AI reviewed Jun 30, 2026

overlookmotel force-pushed the om/06-29-refactor_ast_remove_inherit_variants_macro branch from 36bf6df to 77fd40f Compare June 30, 2026 10:12

overlookmotel force-pushed the om/06-29-docs_ast_macros_document_fields_of_structdetails_ branch from 0f34447 to 42dd69e Compare June 30, 2026 10:12

graphite-app Bot force-pushed the om/06-29-docs_ast_macros_document_fields_of_structdetails_ branch from 42dd69e to f7e10d3 Compare June 30, 2026 13:10

graphite-app Bot force-pushed the om/06-29-refactor_ast_remove_inherit_variants_macro branch from 77fd40f to ae158ec Compare June 30, 2026 13:11

chatgpt-codex-connector Bot reviewed Jun 30, 2026

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Comment thread tasks/ast_tools/src/generators/inherit_variants.rs

overlookmotel force-pushed the om/06-29-docs_ast_macros_document_fields_of_structdetails_ branch from f7e10d3 to c604411 Compare June 30, 2026 14:47

overlookmotel force-pushed the om/06-29-refactor_ast_remove_inherit_variants_macro branch from ae158ec to c16f762 Compare June 30, 2026 14:47

graphite-app Bot force-pushed the om/06-29-docs_ast_macros_document_fields_of_structdetails_ branch from c604411 to 37cbf88 Compare June 30, 2026 16:32

graphite-app Bot force-pushed the om/06-29-refactor_ast_remove_inherit_variants_macro branch from c16f762 to be17950 Compare June 30, 2026 16:33

Base automatically changed from om/06-29-docs_ast_macros_document_fields_of_structdetails_ to main June 30, 2026 16:41

graphite-app Bot merged commit be17950 into main Jun 30, 2026
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graphite-app Bot deleted the om/06-29-refactor_ast_remove_inherit_variants_macro branch June 30, 2026 16:43

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refactor(ast): remove `inherit_variants!` macro#23960

refactor(ast): remove `inherit_variants!` macro#23960
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