09bc67b915
stricter hidden type wf-check [based on #115008] Original work by `@aliemjay` in #115008. A huge thanks to them for originally figuring out this approach ❤️ Fixes https://github.com/rust-lang/rust/issues/114728 Fixes https://github.com/rust-lang/rust/issues/114572 Instead of adding the `WellFormed` obligations when relating opaque types, we now always emit such an obligation when defining the hidden type. This causes nested opaque types which aren't wf to error, see the comment below for the described impact. I believe this change to be desirable as it significantly reduces complexity by removing special-cases. It also caused an issue with RPITIT: in defaulted trait methods, we add a `Projection(synthetic_assoc, rpit_of_trait_method)` clause to the `param_env`. This clause is not added to the `ParamEnv` of the nested coroutines. This caused a normalization failure in `fn check_coroutine_obligations` with the new solver. I fixed that by using the env of the typeck root instead. r? `@oli-obk` |
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| README.md | ||
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.