Basically, `Iterator` is re-exported via several steps, which happened to not be
resolved yet when we got to the prelude import, but since the name resolved to
the reexport from `core::iter` (just to no actual items), we gave up trying to
resolve it further.
Maybe part of the problem is that we can have
`PartialResolvedImport::Unresolved` or `PartialResolvedImport::Indeterminate`
with `None` in all namespaces, and handle them differently.
Fixes#2683.
The `-` turned into a `+` during a refactoring.
The original issue was caused by `Read` resolving wrongly to a trait without
type parameters instead of a struct with one parameter; this only fixes the
crash, not the wrong resolution.
2661: Implement infer await from async function r=flodiebold a=edwin0cheng
This PR is my attempt for trying to add support for infer `.await` expression from an `async` function, by desugaring its return type to `Impl Future<Output=RetType>`.
Note that I don't know it is supposed to desugaring it in that phase, if it is not suitable in current design, just feel free to reject it :)
r=@flodiebold
Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>
It's not very different, except we can directly use Salsa IDs instead of casting
them. This means we need to refactor the handling of errors to get rid of
UNKNOWN_TRAIT though.
2623: Add support macros in impl blocks r=matklad a=edwin0cheng
This PR add support for macros in impl blocks, which reuse `Expander` for macro expansion.
see also: #2459
Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>
When calling a function, argument-position impl Trait is transparent; same for
return-position impl Trait when inside the function. So in these cases, we need
to represent that type not by `Ty::Opaque`, but by a type variable that can be
unified with whatever flows into there.
If we are expecting a `&Foo` and get a `&something`, when checking the
`something`, we are *expecting* a `Foo`, but we shouldn't try to unify whatever
we get with that expectation, because it could actually be a `&Foo`, and `&&Foo`
coerces to `&Foo`. So this fixes quite a few false type mismatches.
