4227: Report invalid, nested, multi-segment crate-paths r=matklad a=djrenren
There was a bug in the previous path-validating code that didn't detect multi-segment paths that started with `crate`.
```rust
// Successfully reported
use foo::{crate};
// BUG: was not being reported
use foo::{crate::bar};
```
This was due to my confusion about path-associativity. That is, the path with no qualifier is the innermost path, not the outermost. I've updated the code with a lot of comments to explain what's going on.
This bug was discovered when I found an erroneous `ok` test which I reported here:
https://github.com/rust-analyzer/rust-analyzer/issues/4226
This test now fails and has been modified, hopefully in the spirit of the original test, to be correct. Sorry about submitting the bug in the first place!
Co-authored-by: John Renner <john@jrenner.net>
The sytax tree output files now use .rast extension
(rust-analyzer syntax tree or rust abstract syntax tree
(whatever)).
This format has a editors/code/ra_syntax_tree.tmGrammar.json declaration
that supplies nice syntax highlighting for .rast files.
We treat macro calls as expressions (there's appropriate Into impl),
which causes problem if there's expresison and non-expression macro in
the same node (like in the match arm).
We fix this problem by nesting macor patterns into another node (the
same way we nest path into PathExpr or PathPat). Ideally, we probably
should add a similar nesting for macro expressions, but that needs
some careful thinking about macros in blocks: `{ am_i_expression!() }`.
