Rollup merge of #70982 - ldm0:fncoerce, r=eddyb

Normalize function signature in function casting check procedure

Fixes #54094
```rust
trait Zoo {
    type X;
}

impl Zoo for u16 {
    type X = usize;
}

fn foo(abc: <u16 as Zoo>::X) {}

fn main() {
    let x: *const u8 = foo as _;
}
```

Currently a `FnDef` need to be checked if it's able to cast to `FnPtr` before it is actually casted. But the signature of `FnPtr` target's associated types are not normalized:

https://github.com/rust-lang/rust/blob/96d77f0e5f103612d62b85938aacfb33f5768433/src/librustc_typeck/check/cast.rs#L536-L553
However, during the coercion check, the signature of `FnPtr` target's associated types are normalized (The `<u16 as Zoo>::X` turns into `usize`).

https://github.com/rust-lang/rust/blob/96d77f0e5f103612d62b85938aacfb33f5768433/src/librustc_typeck/check/coercion.rs#L687-L729

This inconsistency leads to the error:`Err(Sorts(ExpectedFound { expected: <u16 as Zoo>::X, found: usize }))`.

0 files changed, 0 insertions, 0 deletions