perf(isolated_declarations): use `TakeIn` not `CloneIn` by overlookmotel · Pull Request #23847 · oxc-project/oxc

overlookmotel · 2026-06-26T19:10:21Z

There's no need to clone the node here. Both call sites already cloned the entire BindingPattern before calling remove_assignments_from_kind.

Instead use take_in, which is much cheaper if the pattern is deeply nested.

BindingPattern::take_in is cheaper than AssignmentPattern::take_in, so do it that way around.

oxc/crates/oxc_ast/src/generated/derive_dummy.rs

Lines 1071 to 1078 in 84a5aa3

    
           impl<'a> Dummy<'a> for BindingPattern<'a> { 
        
               /// Create a dummy [`BindingPattern`]. 
        
               /// 
        
               /// Has cost of making 1 allocation (32 bytes). 
        
               fn dummy(allocator: &'a Allocator) -> Self { 
        
                   Self::BindingIdentifier(Dummy::dummy(allocator)) 
        
               } 
        
           }

oxc/crates/oxc_ast/src/generated/derive_dummy.rs

Lines 1080 to 1092 in 84a5aa3

    
           impl<'a> Dummy<'a> for AssignmentPattern<'a> { 
        
               /// Create a dummy [`AssignmentPattern`]. 
        
               /// 
        
               /// Has cost of making 2 allocations (48 bytes). 
        
               fn dummy(allocator: &'a Allocator) -> Self { 
        
                   Self { 
        
                       node_id: Dummy::dummy(allocator), 
        
                       span: Dummy::dummy(allocator), 
        
                       left: Dummy::dummy(allocator), 
        
                       right: Dummy::dummy(allocator), 
        
                   } 
        
               } 
        
           }

overlookmotel · 2026-06-26T19:10:33Z

perf(isolated_declarations): use TakeIn not CloneIn #23847 👈 (View in Graphite)
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codspeed-hq · 2026-06-26T19:15:25Z

Merging this PR will not alter performance

✅ 52 untouched benchmarks
⏩ 19 skipped benchmarks¹

_{Comparing om/06-26-perf_isolated_declarations_use_takein_not_clonein_ (ddb771b) with main (84a5aa3)}

19 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. ↩

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Dunqing · 2026-06-29T01:37:43Z

Merge activity

Jun 29, 1:37 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Jun 29, 1:37 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Jun 29, 1:42 AM UTC: Merged by the Graphite merge queue.

There's no need to clone the node here. Both call sites already cloned the entire `BindingPattern` before calling `remove_assignments_from_kind`. Instead use `take_in`, which is much cheaper if the pattern is deeply nested. `BindingPattern::take_in` is cheaper than `AssignmentPattern::take_in`, so do it that way around. https://github.com/oxc-project/oxc/blob/84a5aa3246bf514d6544384bbb577cd989c9d3b9/crates/oxc_ast/src/generated/derive_dummy.rs#L1071-L1078 https://github.com/oxc-project/oxc/blob/84a5aa3246bf514d6544384bbb577cd989c9d3b9/crates/oxc_ast/src/generated/derive_dummy.rs#L1080-L1092

### 💥 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>

There's no need to clone the node here. Both call sites already cloned the entire `BindingPattern` before calling `remove_assignments_from_kind`. Instead use `take_in`, which is much cheaper if the pattern is deeply nested. `BindingPattern::take_in` is cheaper than `AssignmentPattern::take_in`, so do it that way around. https://github.com/oxc-project/oxc/blob/84a5aa3246bf514d6544384bbb577cd989c9d3b9/crates/oxc_ast/src/generated/derive_dummy.rs#L1071-L1078 https://github.com/oxc-project/oxc/blob/84a5aa3246bf514d6544384bbb577cd989c9d3b9/crates/oxc_ast/src/generated/derive_dummy.rs#L1080-L1092

### 💥 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>

github-actions Bot added the A-isolated-declarations Isolated Declarations label Jun 26, 2026

overlookmotel assigned Dunqing Jun 26, 2026

overlookmotel force-pushed the om/06-26-perf_isolated_declarations_use_takein_not_clonein_ branch from 1af7268 to ddb771b Compare June 26, 2026 19:48

overlookmotel marked this pull request as ready for review June 26, 2026 19:53

overlookmotel requested a review from Dunqing as a code owner June 26, 2026 19:53

Copilot AI review requested due to automatic review settings June 26, 2026 19:53

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graphite-app Bot force-pushed the om/06-26-perf_isolated_declarations_use_takein_not_clonein_ branch from ddb771b to 53d083f Compare June 29, 2026 01:38

graphite-app Bot merged commit 53d083f into main Jun 29, 2026
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graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label Jun 29, 2026

graphite-app Bot deleted the om/06-26-perf_isolated_declarations_use_takein_not_clonein_ branch June 29, 2026 01:42

oxc-guard Bot mentioned this pull request Jun 29, 2026

release(crates): oxc v0.138.0 #23934

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perf(isolated_declarations): use `TakeIn` not `CloneIn`#23847

perf(isolated_declarations): use `TakeIn` not `CloneIn`#23847
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	impl<'a> Dummy<'a> for BindingPattern<'a> {
	/// Create a dummy [`BindingPattern`].
	///
	/// Has cost of making 1 allocation (32 bytes).
	fn dummy(allocator: &'a Allocator) -> Self {
	Self::BindingIdentifier(Dummy::dummy(allocator))
	}
	}

	impl<'a> Dummy<'a> for AssignmentPattern<'a> {
	/// Create a dummy [`AssignmentPattern`].
	///
	/// Has cost of making 2 allocations (48 bytes).
	fn dummy(allocator: &'a Allocator) -> Self {
	Self {
	node_id: Dummy::dummy(allocator),
	span: Dummy::dummy(allocator),
	left: Dummy::dummy(allocator),
	right: Dummy::dummy(allocator),
	}
	}
	}

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Merging this PR will not alter performance

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