Fix ICE in normalization during closure capture analysis (#149746) #149800
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| let input = self.typing_env.as_query_input(arg); | ||
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| // 2. Use unwrap_or(arg) to return the original arg if it fails | ||
| self.tcx.try_normalize_generic_arg_after_erasing_regions(input).unwrap_or(arg) |
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we're intentionally using a bug! here as we're in normalize_generic_arg_after_erasing_regions.
The issue happens in the caller:
- we either have to change the caller to use
try_normalize...to avoid this ICE if the error is unavoidable - or prevent this error entirely by not calling
normalize_...for types which aren#t well-formed
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Thanks for the feedback @lcnr ! I have reverted the global change in rustc_middle and moved the fix to compiler/rustc_hir_typeck/src/upvar.rs as requested. specifically, I updated the needs_drop closure within has_significant_drop_outside_of_captures to use try_normalize_erasing_regions; if normalization fails, it now conservatively returns false (assuming no significant drop) instead of panicking.
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This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed. Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers. |
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@lcnr anything else that needs to be changed? |
Co-authored-by: León Orell Valerian Liehr <me@fmease.dev>
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This fixes an internal compiler error that occurred when normalizing associated types during closure capture analysis.
The Fix: Modified rustc_middle/src/ty/normalize_erasing_regions.rs to gracefully handle projection normalization failures instead of panicking when analyzing closure captures.
Regression Test: Added tests/ui/associated-types/normalization-ice-issue-149746.rs, a reproduction case involving complex associated type projections (<() as Owner>::Ty) that previously crashed the compiler. Verified it now emits a standard type error (E0277).
Fixes #149746