rust/compiler/rustc_middle
Matthias Krüger dd0fa6f871
Rollup merge of #98496 - BoxyUwU:instancers_bad_equality, r=lcnr
make `compare_const_impl` a query and use it in `instance.rs`

Fixes #88365

the bug in #88365 was caused by some `instance.rs` code using the `PartialEq` impl on `Ty` to check that the type of the associated const in an impl is the same as the type of the associated const in the trait definition. This was wrong for two reasons:
- the check typeck does is that the impl type is a subtype of the trait definition's type (see `mismatched_impl_ty_2.rs` which [was ICEing](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=f6d60ebe6745011f0d52ab2bc712025d) before this PR on stable)
- it assumes that if two types are equal then the `PartialEq` impl will reflect that which isnt true for higher ranked types or type level constants when `feature(generic_const_exprs)` is enabled (see `mismatched_impl_ty_3.rs` for higher ranked types which was [ICEing on stable](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=d7af131a655ed515b035624626c62c71))

r? `@lcnr`
2022-10-06 16:29:43 +02:00
..
src Rollup merge of #98496 - BoxyUwU:instancers_bad_equality, r=lcnr 2022-10-06 16:29:43 +02:00
Cargo.toml Move utils from rustc_middle to rustc_ty_utils 2022-10-03 09:12:03 -05:00
README.md

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