perf(allocator): remove unwrap from ReplaceWith#24365
Merged
graphite-app[bot] merged 1 commit intoJul 10, 2026
Merged
Conversation
Member
Author
How to use the Graphite Merge QueueAdd either label to this PR to merge it via the merge queue:
You must have a Graphite account in order to use the merge queue. Sign up using this link. An organization admin has enabled the Graphite Merge Queue in this repository. Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue. This stack of pull requests is managed by Graphite. Learn more about stacking. |
Contributor
There was a problem hiding this comment.
Pull request overview
This PR updates ReplaceWith’s panic-path dummy allocator creation to use Rust 1.95’s Vec::push_mut, removing an infallible unwrap and letting the compiler eliminate an unnecessary panicking branch.
Changes:
- Replace
push+last().unwrap()withpush_mutto obtain the newly pushed allocator reference directly. - Minor comment wording/formatting adjustments around the allocator push and reference acquisition.
Merging this PR will not alter performance
Comparing 
Footnotes
|
Member
Author
Merge activity
|
#24359 bumped our MSRV to 1.95.0. We can now use `Vec::push_mut`. Use it in `ReplaceWith` to remove an infallible `unwrap` which compiler previously couldn't prove was infallible. Previously it emitted a panicking branch, now it doesn't. This code is on a cold path, so perf impact is miniscule, but why not use the best API for the job?
graphite-app
Bot
force-pushed
the
om/07-10-perf_allocator_remove_unwrap_from_replacewith_
branch
from
July 10, 2026 19:58
8dc3e75 to
3ff0234
Compare
graphite-app
Bot
deleted the
om/07-10-perf_allocator_remove_unwrap_from_replacewith_
branch
July 10, 2026 20:03
Boshen
added a commit
that referenced
this pull request
Jul 14, 2026
### 🚀 Features - 616bfa2 minifier: Remove unreachable code after terminating statements (#24441) (Dunqing) - ddab89a data_structures: Add `likely` and `unlikely` functions (#24368) (overlookmotel) - a3a39f9 react_compiler: Implement enableEmitHookGuards codegen (#24329) (Boshen) - b79eef7 minifier: Apply De Morgan's law to negated comparison chains in jump guards and loop tests (#24279) (Dunqing) - 34ff7b4 minifier: Drop write-only property assignments to unused local bindings by default (#24112) (Dunqing) - 1b829d8 semantic: Record const enums in EnumData (#24268) (Dunqing) - ba0944c semantic: Add `Scoping::set_symbol_span` (#24221) (camc314) ### 🐛 Bug Fixes - 7d33363 minifier: Preserve guaranteed throws from class heritage evaluation (#24349) (Dunqing) - 058a62f semantic: Track ambient contexts in `SemanticBuilder` (#24327) (camc314) - 721eb0b transformer/decorator: Scope accessor class binding (#24330) (camc314) - 1ebdce3 semantic: Allow reserved keywords in ambient declaration types (#24325) (camc314) - 460176a track-memory-allocations: Exclude arena chunks from Sys allocs (#24292) (Dunqing) - af4922b transformer: Clear lowered namespace redeclarations (#24300) (camc314) - ffd2765 semantic: Mark declared computed `MethodDefinition`s as type references (#24296) (camc314) - f17514b isolated-declarations: Emit const readonly fields as types (#24288) (camc314) - 40f769d minifier: Make `__proto__` write tracking execution-order independent (#24280) (Dunqing) - 6371fed transformer: Remove stale enum member bindings (#24272) (camc314) - f05dfab transformer: Correct symbol flags for lowered namespaces (#24271) (Dunqing) - 84eeb55 transformer: Correct symbol flags for lowered enums (#24269) (Dunqing) - c3057da transformer: Preserve generated class binding spans (#24220) (camc314) - 8260096 transformer: Correct span for lowered namespace symbol (#24222) (camc314) - 42d00d3 semantic: Mark declared class heritage as type references (#24237) (camc314) - 588d997 semantic: Mark TS `PropertyDefinition`s computed fields as type references (#24233) (camc314) - 9b95632 semantic: Mark computed method keys in `TSMethodSignature`s as type references (#24232) (camc314) ### ⚡ Performance - 5b26643 transformer_plugins: Dispatch global defines by trailing name (#23666) (Boshen) - dce0f29 react_compiler: Replace all compiled functions in a single AST walk (#24403) (Boshen) - f85f0d8 ast: Delegate inherited enum variants in clone_in and estree derives (#23555) (Boshen) - 3ff0234 allocator: Remove `unwrap` from `ReplaceWith` (#24365) (overlookmotel) - ab22e80 transformer: Fix Rust 1.97 performance regression (#24354) (camc314) - b47585c parser: Use `ReplaceWith` instead of `TakeIn` (#24018) (overlookmotel) - b227a06 minifier: Use `ReplaceWith` instead of `TakeIn` (#24017) (overlookmotel) Co-authored-by: Boshen <[email protected]>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
#24359 bumped our MSRV to 1.95.0. We can now use
Vec::push_mut.Use it in
ReplaceWithto remove an infallibleunwrapwhich compiler previously couldn't prove was infallible. Previously it emitted a panicking branch, now it doesn't.This code is on a cold path, so perf impact is miniscule, but why not use the best API for the job?