[6.2] Sema: Never record argument label mismatches for unlabeled trailing closures #82156
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…losures Fixes a crash on invalid. The previous logic was causing a label mismatch constraint fix to be recorded for an unlabeled trailing closure argument matching a variadic paramater after a late recovery argument claim in `matchCallArgumentsImpl`, because the recovery claiming skips arguments matching defaulted parameters, but not variadic ones. We may want to reconsider that last part, but currently it regresses the quality of some diagnostics, and this is a targeted fix. The previous behavior is fine because the diagnosis routine associate with the constraint fix (`diagnoseArgumentLabelError`) skips unlabeled trailing closures when tallying labeling issues — *unless* there are no other issues and the tally is zero, which we assert it is not. Fixes rdar://152313388. (cherry picked from commit f2e1420)
bnbarham
approved these changes
Jun 10, 2025
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@swift-ci please test |
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Explanation:
Fixes a crash on invalid. The previous logic was causing a label mismatch constraint fix to be recorded for an unlabeled trailing closure argument matching a variadic paramater after a late recovery argument claim in
matchCallArgumentsImpl, because the recovery claiming skips arguments matching defaulted parameters, but not variadic ones. We may want to reconsider that last part, but currently it regresses the quality of some diagnostics, and this is a targeted fix.The previous behavior is fine because the diagnosis routine associate with the constraint fix (
diagnoseArgumentLabelError) skips unlabeled trailing closures when tallying labeling issues — unless there are no other issues and the tally is zero, which we assert it is not.Does not miscompile with assertions disabled.
Scope: Unlabeled trailing closure argument matching diagnostics QoI.
Issues: rdar://152313388.
Original PRs: Sema: Never record argument label mismatches for unlabeled trailing closures #82020.
Risk: Low. Worst-case potential regression should be in diagnostic quality.
Testing: Passed source compatibility suite.
Reviewers: @xedin