Fix explicit deref problems in closure capture
fix the `need-mut` part of #14562
Perhaps surprisingly, it wasn't unique immutable borrow. The code still doesn't emit any of them, and I think those won't happen in edition 2021 (which is currently the only thing implemented), since we always capture `&mut *x` instead of `&mut x`. But I'm not very sure about it.
internal: Warn when loading sysroot fails to find the core library
Should help a bit more with user experience, before we only logged this now we show it in the status
Closes https://github.com/rust-lang/rust-analyzer/issues/11606
feat: make inlay hints insertable
Part of #13812
This PR implements text edit for inlay hints. When an inlay hint contain text edit, user can "accept" it (e.g. by double-clicking in VS Code) to make the hint actual code (effectively deprecating the hint itself).
This PR does not implement auto import despite the original request; text edits only insert qualified types along with necessary punctuation. I feel there are some missing pieces to implement efficient auto import (in particular, type traversal function with early exit) so left it for future work. Even without it, user can use `replace_qualified_name_with_use` assist after accepting the edit to achieve the same result.
I implemented for the following inlay hints:
- top-level identifier pattern in let statements
- top-level identifier pattern in closure parameters
- closure return type when its has block body
One somewhat strange interaction can be observed when top-level identifier pattern has subpattern: text edit inserts type annotation in different place than the inlay hint. Do we want to allow it or should we not provide text edits for these cases at all?
```rust
let a /* inlay hint shown here */ @ (b, c) = foo();
let a @ (b, c) /* text edit inserts types here */ = foo();
```
Don't suggest unstable items on stable toolchain
Closes#3020
This PR implements stability check in `ide-completion` so that unstable items are only suggested if you're on nightly toolchain.
It's a bit unfortunate `CompletionContext::check_stability()` is spammed all over the crate, but we should call it before building `CompletionItem` as you cannot get attributes on the item it's completing from that struct. I looked up every callsite of `Builder::add_to()`, `Completions::add[_opt]()`, and`Completions::add_all()` and inserted the check wherever necessary.
The tests are admittedly incomplete in that I didn't add tests for every kind of item as I thought that would be too big and not worthwhile. I copy-pasted some existing basic tests in every test module and adjusted them.
