Rework value parameter parsing

- `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

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) {}
+}