diff --git a/crates/ide/src/completion/complete_qualified_path.rs b/crates/ide/src/completion/complete_qualified_path.rs
index 79de5079278..00e89f0fdf2 100644
--- a/crates/ide/src/completion/complete_qualified_path.rs
+++ b/crates/ide/src/completion/complete_qualified_path.rs
@@ -730,4 +730,26 @@ fn f() {}
             expect![[""]],
         );
     }
+
+    #[test]
+    fn completes_function() {
+        check(
+            r#"
+fn foo(
+    a: i32,
+    b: i32
+) {
+
+}
+
+fn main() {
+    fo<|>
+}
+"#,
+            expect![[r#"
+                fn foo(…) fn foo(a: i32, b: i32)
+                fn main() fn main()
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide/src/display.rs b/crates/ide/src/display.rs
index 41b5bdc490c..2484dbbf12b 100644
--- a/crates/ide/src/display.rs
+++ b/crates/ide/src/display.rs
@@ -41,7 +41,14 @@ pub(crate) fn function_declaration(node: &ast::Fn) -> String {
         format_to!(buf, "{}", type_params);
     }
     if let Some(param_list) = node.param_list() {
-        format_to!(buf, "{}", param_list);
+        let params: Vec<String> = param_list
+            .self_param()
+            .into_iter()
+            .map(|self_param| self_param.to_string())
+            .chain(param_list.params().map(|param| param.to_string()))
+            .collect();
+        // Useful to inline parameters
+        format_to!(buf, "({})", params.join(", "));
     }
     if let Some(ret_type) = node.ret_type() {
         if ret_type.ty().is_some() {