11598: feat: Parse destructuring assignment r=Veykril a=ChayimFriedman2
Part of #11532.
Lowering is not as easy and may not even be feasible right now as it requires generating identifiers: `(a, b) = (b, a)` is desugared into
```rust
{
let (<gensym_a>, <gensym_b>) = (b, a);
a = <gensym_a>;
b = <gensym_b>;
}
```
rustc uses hygiene to implement that, but we don't support hygiene yet.
However, I think parsing was the main problem as lowering will just affect type inference, and while `{unknown}` is not nice it's much better than a syntax error.
I'm still looking for the best way to do lowering, though.
Fixes#11454.
Co-authored-by: Chayim Refael Friedman <chayimfr@gmail.com>
- don't return the receiver type from method resolution; instead just
return the autorefs/autoderefs that happened and repeat them. This
ensures all the effects like trait obligations and whatever we learned
about type variables from derefing them are actually applied. Also, it
allows us to get rid of `decanonicalize_ty`, which was just wrong in
principle.
- Autoderef itself now directly works with an inference table. Sadly
this has the effect of making it harder to use as an iterator, often
requiring manual `while let` loops. (rustc works around this by using
inner mutability in the inference context, so that things like unifying
types don't require a unique reference.)
- We now record the adjustments (autoref/deref) for method receivers
and index expressions, which we didn't before.
- Removed the redundant crate parameter from method resolution, since
the trait_env contains the crate as well.
- in the HIR API, the methods now take a scope to determine the trait env.
`Type` carries a trait env, but I think that's probably a bad decision
because it's easy to create it with the wrong env, e.g. by using
`Adt::ty`. This mostly didn't matter so far because
`iterate_method_candidates` took a crate parameter and ignored
`self.krate`, but the trait env would still have been wrong in those
cases, which I think would give some wrong results in some edge cases.
Fixes#10058.
11182: fix: don't panic on seeing an unexpected offset r=Veykril a=dimbleby
Intended as a fix, or at least a sticking plaster, for #11081.
I have arranged that [offset()](1ba9a924d7/crates/ide_db/src/line_index.rs (L105-L107)) returns `Option<TextSize>` instead of going out of bounds; other changes are the result of following the compiler after doing this.
Perhaps there's still an issue here - I suppose the server and client have gotten out of sync and that probably shouldn't happen in the first place? I see that https://github.com/rust-analyzer/rust-analyzer/issues/10138#issuecomment-913727554 suggests what sounds like a more substantial fix which I think might be aimed in this direction. So perhaps that one should be left open to cover such things?
Meanwhile, I hope that not-crashing is a good improvement: and I can confirm that it works out just fine in the repro I have at #11081.
Co-authored-by: David Hotham <david.hotham@metaswitch.com>
