Merge #3040

3040: Rework value parameter parsing r=matklad a=tobz1000

Fixes #2847.

- `Fn__(...)` parameters with idents/patterns no longer parse
- Trait function parameters with arbitrary patterns parse
- Trait function parameters without idents/patterns no longer parse
- `fn(...)` parameters no longer parse with patterns other than a single ident

__Question__: The pre-existing test `param_list_opt_patterns` has been kept as-is, although the name no longer makes sense (it's testing `Fn__(...)` params, which aren't allowed patterns any more). What would be best to do about this?

Co-authored-by: Toby Dimmick <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0152_fn_patterns.rs b/crates/ra_syntax/test_data/parser/inline/ok/0152_fn_patterns.rs
new file mode 100644
index 000000000..b49e872d7
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0152_fn_patterns.rs
@@ -0,0 +1,6 @@
+impl U {
+    fn f1((a, b): (usize, usize)) {}
+    fn f2(S { a, b }: S) {}
+    fn f3(NewType(a): NewType) {}
+    fn f4(&&a: &&usize) {}
+}