fix(minifier): preserve annotation comments when inlining single-use variables during DCE#21567
Merged
graphite-app[bot] merged 1 commit intomainfrom Apr 20, 2026
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. |
Merging this PR will not alter performance
Comparing 
Footnotes
|
Member
Author
|
This is actually similar to what the workaround at vitejs/vite#21950 (comment) does. |
sapphi-red
approved these changes
Apr 20, 2026
Member
Author
Merge activity
|
…variables during DCE (#21567) When `substitute_single_use_symbol_in_expression` inlines a single-use `const` variable, it replaced the identifier with the init expression using `replacement.take_in()`, which kept the replacement's original span from the variable declaration site. Since comments are associated with AST nodes via the `attached_to` field (keyed by span start), `@vite-ignore` and `webpackIgnore` comments attached to the original identifier were lost because the replacement expression had a different span start. This only manifested in DCE mode (used by rolldown) because in full optimization mode, `inline_identifier_reference` runs first and correctly preserves the span via `ctx.value_to_expr(expr.span(), ...)`. The fix preserves the target identifier's span on the replacement expression after substitution. Fixes rolldown/rolldown#8248 Closes vitejs/vite#21950
c9588f4 to
385eb94
Compare
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
2 participants
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.
When
substitute_single_use_symbol_in_expressioninlines a single-useconstvariable, it replaced the identifier with the init expression usingreplacement.take_in(), which kept the replacement's original span from the variable declaration site. Since comments are associated with AST nodes via theattached_tofield (keyed by span start),@vite-ignoreandwebpackIgnorecomments attached to the original identifier were lost because the replacement expression had a different span start.This only manifested in DCE mode (used by rolldown) because in full optimization mode,
inline_identifier_referenceruns first and correctly preserves the span viactx.value_to_expr(expr.span(), ...).The fix preserves the target identifier's span on the replacement expression after substitution.
Fixes rolldown/rolldown#8248
Closes vitejs/vite#21950