This is working, but I'm not that happy with how the lowering works. We might
need an additional representation between `TypeRef` and `Ty` where names are
resolved and `impl Trait` bounds are separated out, but things like inference
variables don't exist and `impl Trait` is always represented the same
way.
Also note that this doesn't implement correct handling of RPIT *inside* the
function (which involves turning the `impl Trait`s into variables and creating
obligations for them). That intermediate representation might help there as
well.
4651: Use first match branch in case of type mismatch, not last r=kjeremy a=flodiebold
The comment says this was intentional, but I do agree with #4304 that it makes
more sense the other way around (for if/else as well).
Fixes#4304.
Co-authored-by: Florian Diebold <florian.diebold@freiheit.com>
Function pointers can be 'higher-ranked' over lifetimes, which is why they're
not an application type in Chalk, but since we don't model lifetimes it doesn't
matter for us yet.
4497: Create LowerCtx on the fly r=matklad a=edwin0cheng
Previously we create `LowerCtx` at the beginning of lowering, however, the hygiene content is in fact changing between macro expression expanding.
This PR change it to create the `LowerCtx` on the fly to fix above bug.
However, #4465 is not fixed by this PR, the goto-def is still not work yet. It only fixed the infer part.
Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>
This fixes an issue where the following code sample would fail to infer
the type contained in the option:
```rust
fn main() {
let mut end = None; // TODO: Fix inference for this in RA
loop {
end = Some(true);
}
}
```
4175: Introduce HirDisplay method for rendering source code & use it in add_function assist r=flodiebold a=TimoFreiberg
Next feature for #3639.
So far the only change in the new `HirDisplay` method is that paths are qualified, but more changes will be necessary (omitting the function name from function types, returning an error instead of printing `"{unknown}"`, probably more).
Is that approach okay?
Co-authored-by: Timo Freiberg <timo.freiberg@gmail.com>
E.g. in
```rust
match x {
1 => function1,
2 => function2,
}
```
we need to try coercing both to pointers. Turns out this is a special case in
rustc as well (see the link in the comment).
Divergence here means that for some reason, the end of a block will not be
reached. We tried to model this just using the never type, but that doesn't work
fully (e.g. in `let x = { loop {}; "foo" };` x should still have type `&str`);
so this introduces a `diverges` flag that the type checker keeps track of, like
rustc does.
4173: Use core instead of std for builtin derive macros r=edwin0cheng a=edwin0cheng
Fixed#4087.
We can't use `$crate` here right now because :
1. We have to able to detect `macro` 2.0 in collecting phase for finding `rustc_builtin_macro` attrs.
2. And we have to make hygiene works for builtin derive macro.
r= @flodiebold
Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>
So e.g. if we have `fn foo<T: SomeTrait<u32>>() -> T::Item`, we want to lower
that to `<T as SomeTrait<u32>>::Item` and not `<T as SomeTrait<_>>::Item`.
We need to shift in when we're substituting inside a binder.
This should fix#4053 (it doesn't fix the occasional overflow that also occurs
on the Diesel codebase though).
