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Matthias Krüger
db9591cfb6
Check normalized call signature for WF in mir typeck Unfortunately we don't check that the built-in implementations for `Fn*` traits are actually well-formed in the same way that we do for user-provided impls. Essentially, when checking a call terminator, we end up with a signature that references an unnormalized `<[closure] as FnOnce<...>>::Output` in its output. That output type, due to the built-in impl, doesn't follow the expected rule that `WF(ty)` implies `WF(normalized(ty))`. We fix this by also checking the normalized signature here. **See** boxy's detailed and useful explanation comment which explains this in more detail: https://github.com/rust-lang/rust/issues/114936#issuecomment-1710388741 Fixes #114936 Fixes #118876 r? types cc ``@BoxyUwU`` ``@lcnr``