692d764e53
Map RPITIT's opaque type bounds back from projections to opaques
An RPITIT in a program's AST is eventually translated into both a projection GAT and an opaque. The opaque is used for default trait methods, like:
```
trait Foo {
fn bar() -> impl Sized { 0i32 }
}
```
The item bounds for both the projection and opaque are identical, and both have a *projection* self ty. This is mostly okay, since we can normalize this projection within the default trait method body to the opaque, but it does two things:
1. it leads to bugs in places where we don't normalize item bounds, like `deduce_future_output_from_obligations`
2. it leads to extra match arms that are both suspicious looking and also easy to miss
This PR maps the opaque type bounds of the RPITIT's *opaque* back to the opaque's self type to avoid this quirk. Then we can fix the UI test for #108304 (1.) and also remove a bunch of match arms (2.).
Fixes #108304
r? `@spastorino`
|
||
|---|---|---|
| .. | ||
| abi.rs | ||
| assoc.rs | ||
| common_traits.rs | ||
| consts.rs | ||
| errors.rs | ||
| implied_bounds.rs | ||
| instance.rs | ||
| layout.rs | ||
| layout_sanity_check.rs | ||
| lib.rs | ||
| needs_drop.rs | ||
| opaque_types.rs | ||
| representability.rs | ||
| structural_match.rs | ||
| ty.rs | ||