Add test for #8931 and better checking

1 files changed, 29 insertions, 0 deletions

diff --git a/crates/ide_completion/src/completions/dot.rs b/crates/ide_completion/src/completions/dot.rs
index 7e4efe589..1bff55936 100644
--- a/crates/ide_completion/src/completions/dot.rs
+++ b/crates/ide_completion/src/completions/dot.rs
@@ -454,4 +454,33 @@ mod foo {
             "#]],
         );
     }
+
+    #[test]
+    fn issue_8931() {
+        check(
+            r#"
+#[lang = "fn_once"]
+trait FnOnce<Args> {
+    type Output;
+}
+struct S;
+
+struct Foo;
+impl Foo {
+    fn foo(&self) -> &[u8] { loop {} }
+}
+
+impl S {
+    fn indented(&mut self, f: impl FnOnce(&mut Self)) {
+    }
+
+    fn f(&mut self, v: Foo) {
+        self.indented(|this| v.$0)
+    }
+}
+        "#,
+            expect![[r#"
+            "#]],
+        );
+    }
 }