When we have one of these, the `Trait` doesn't need to be in scope to call its
methods. So we need to consider this when looking for method
candidates. (Actually I think the same is true when we have a bound `T:
some::Trait`, but we don't handle that yet).
At the same time, since Chalk doesn't handle these types yet, add a small hack
to skip Chalk in method resolution and just consider `impl Trait: Trait` always
true. This is enough to e.g. get completions for `impl Trait`, but since we
don't do any unification we won't infer the return type of e.g. `impl
Into<i64>::into()`.
- refactor bounds handling in the AST a bit
- add HIR for bounds
- add `Ty::Dyn` and `Ty::Opaque` variants and lower `dyn Trait` / `impl Trait`
syntax to them
This adds three different representations, copied from the Chalk model:
- `Ty::Projection` is an associated type projection written somewhere in the
code, like `<Foo as Trait>::Bar`.
- `Ty::UnselectedProjection` is similar, but we don't know the trait
yet (`Foo::Bar`).
- The above representations are normalized to their actual types during type
inference. When that isn't possible, for example for `T::Item` inside an `fn
foo<T: Iterator>`, the type is normalized to an application type with
`TypeCtor::AssociatedType`.
1562: Continue support for .await r=matklad a=unrealhoang
- add await expr to ast and HIR Expr
- infer type for `.await`
Co-authored-by: Unreal Hoang <unrealhoang@gmail.com>
1515: Trait environment r=matklad a=flodiebold
This adds the environment, i.e. the set of `where` clauses in scope, when solving trait goals. That means that e.g. in
```rust
fn foo<T: SomeTrait>(t: T) {}
```
, we are able to complete methods of `SomeTrait` on the `t`. This affects the trait APIs quite a bit (since every method that needs to be able to solve for some trait needs to get this environment somehow), so I thought I'd do it rather sooner than later ;)
Co-authored-by: Florian Diebold <flodiebold@gmail.com>
