e52e7115c7
correctly deal with user type ascriptions in pat supersedes #93856 `thir::PatKind::AscribeUserType` previously resulted in `CanonicalUserTypeAnnotations` where the inferred type already had a subtyping relation according to `variance` to the `user_ty`. The bug can pretty much be summarized as follows: - during mir building - `user_ty -> inferred_ty`: considers variance - `StatementKind::AscribeUserType`: `inferred_ty` is the type of the place, so no variance needed - during mir borrowck - `user_ty -> inferred_ty`: does not consider variance - `StatementKind::AscribeUserType`: applies variance This mostly worked fine. The lifetimes in `inferred_ty` were only bound by its relation to `user_ty` and to the `place` of `StatementKind::AscribeUserType`, so it doesn't matter where exactly the subtyping happens. It does however matter when having higher ranked subtying. At this point the place where the subtyping happens is forced, causing this mismatch between building and borrowck to result in unintended errors. cc #96514 which is pretty much the same issue r? `@nikomatsakis` |
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| .. | ||
| bootstrap | ||
| ci | ||
| doc | ||
| etc | ||
| librustdoc | ||
| llvm-project@4784866596 | ||
| rustdoc-json-types | ||
| test | ||
| tools | ||
| README.md | ||
| stage0.json | ||
| version | ||
This directory contains the source code of the rust project, including:
- The test suite
- The bootstrapping build system
- Various submodules for tools, like rustdoc, rls, etc.
For more information on how various parts of the compiler work, see the rustc dev guide.