Use `typeck_results` to get accurate qpath res for arg mismatch error
Improves error message from "function" to actually what we're calling (e.g. enum variant constrcutor) in a few cases 😸
Do not constraint TAITs when checking impl/trait item compatibility
Check out the UI test for the example.
Open to other approaches to fix this issue -- ideally we _would_ be able to collect this opaque type constraint in a way to use it in `find_opaque_ty_constraints`, so we can report a better mismatch error in the incompatible case, and just allow it in the compatible case. But that seems like a bigger refactor, so I wouldn't want to start it unless someone else thought it was a good idea.
cc #99348
r? ``@oli-obk``
Be more precise when suggesting removal of parens on unit ctor
* Fixes#99240 by only suggesting to remove parens on path exprs, not arbitrary expressions with enum type
* Generalizes by suggesting removal of parens on unit struct, too, because why not?
Remove some usages of `guess_head_span`
No need to pass things through `guess_head_span` if they already point to the head span.
Only major change is that we point to the head span of `enum`s on some errors now, which I prefer.
r? `@cjgillot`
Implement `for<>` lifetime binder for closures
This PR implements RFC 3216 ([TI](https://github.com/rust-lang/rust/issues/97362)) and allows code like the following:
```rust
let _f = for<'a, 'b> |a: &'a A, b: &'b B| -> &'b C { b.c(a) };
// ^^^^^^^^^^^--- new!
```
cc ``@Aaron1011`` ``@cjgillot``
Fix drop-tracking ICE when a struct containing a field with a significant drop is used across an await
Previously, drop-tracking would incorrectly assume the struct would be dropped immediately, which was not true.
Fixes#98476. Also fixes https://github.com/rust-lang/rust/issues/98477, I think because the parent HIR node for type variables is the whole function instead of the expression where the variable is used.
r? `@eholk`
Keep unstable target features for asm feature checking
Inline assembly uses the target features to determine which registers
are available on the current target. However it needs to be able to
access unstable target features for this.
Fixes#99071
Lower let-else in MIR
This MR will switch to lower let-else statements in MIR building instead.
To lower let-else in MIR, we build a mini-switch two branches. One branch leads to the matching case, and the other leads to the `else` block. This arrangement will allow temporary lifetime analysis running as-is so that the temporaries are properly extended according to the same rule applied to regular `let` statements.
cc https://github.com/rust-lang/rust/issues/87335Fix#98672
