fix: Simplify macro statement expansion handling
I only meant to fix https://github.com/rust-lang/rust-analyzer/issues/12644 but that somehow turned into a rewrite of the statement handling ... at least this fixes a few more issues in the IDE layer now
fix: improve whitespace insertion in pretty printer
Fixes#12591
The `=>` token in the macro_rules! should be parsed as one fat arrow, but it ["requires a lot of changes in r-a"](143cc528b1), so I left it for the larger refactoring in the future and put a FIXME note.
feat: Show witnesses of non-exhaustiveness in `missing-match-arm` diagnostic
Shamelessly copied from rustc. Thus reporting format is same.
This extends public api `hir::diagnostics::MissingMatchArms` with `uncovered_patterns: String` field. It does not expose data for implementing a quick fix yet.
-----
Worth to note: current implementation does not give a comprehensive list of missing patterns. Also mentioned in [paper](http://moscova.inria.fr/~maranget/papers/warn/warn.pdf):
> One may think that algorithm I should make an additional effort to provide more
> non-matching values, by systematically computing recursive calls on specialized
> matrices when possible, and by returning a list of all pattern vectors returned by
> recursive calls. We can first observe that it is not possible in general to supply the
> users with all non-matching values, since the signature of integers is (potentially)
> infinite.
fix: trailing ':' on empty inactive reasons
## Description
Fixes trailing ':' even when there is no explanation. e.g.
``` sh
code is inactive due to #[cfg] directives:
```
## Issue
Fixes: #12615
feat: implement destructuring assignment
This is an attempt to implement destructuring assignments, or more specifically, type inference for [assignee expressions](https://doc.rust-lang.org/reference/expressions.html#place-expressions-and-value-expressions).
I'm not sure if this is the right approach, so I don't even expect this to be merged (hence the branch name 😉) but rather want to propose one direction we could choose. I don't mind getting merged if this is good enough though!
Some notes on the implementation choices:
- Assignee expressions are **not** desugared on HIR level unlike rustc, but are inferred directly along with other expressions. This matches the processing of other syntaxes that are desugared in rustc but not in r-a. I find this reasonable because r-a only needs to infer types and it's easier to relate AST nodes and HIR nodes, so I followed it.
- Assignee expressions obviously resemble patterns, so type inference for each kind of pattern and its corresponding assignee expressions share a significant amount of logic. I tried to reuse the type inference functions for patterns by introducing `PatLike` trait which generalizes assignee expressions and patterns.
- This is not the most elegant solution I suspect (and I really don't like the name of the trait!), but it's cleaner and the change is smaller than other ways I experimented, like making the functions generic without such trait, or making them take `Either<ExprId, PatId>` in place of `PatId`.
in case this is merged:
Closes#11532Closes#11839Closes#12322
fix: Report proc macro errors in expressions correctly as well
They didn't have a krate before, resulting in the generic "proc macro not found" error.
Also improve error messages a bit more.
