1 files changed, 2 insertions, 1 deletions

diff --git a/crates/ra_parser/src/grammar/params.rs b/crates/ra_parser/src/grammar/params.rs
index a70f067f9..d027578b6 100644
--- a/crates/ra_parser/src/grammar/params.rs
+++ b/crates/ra_parser/src/grammar/params.rs
@@ -83,9 +83,10 @@ fn value_parameter(p: &mut Parser, flavor: Flavor) {
 
             // test trait_fn_placeholder_parameter
             // trait Foo {
-            //     fn bar(_: u64);
+            //     fn bar(_: u64, mut x: i32);
             // }
             if (la0 == IDENT || la0 == UNDERSCORE) && la1 == COLON
+                || la0 == MUT_KW && la1 == IDENT && la2 == COLON
                 || la0 == AMP && la1 == IDENT && la2 == COLON
                 || la0 == AMP && la1 == MUT_KW && la2 == IDENT && la3 == COLON
             {