KT-1254 "Implement members" gives strange result when implementing a method returning function type

#KT-1254 fixed

idea/testData/codeInsight/overrideImplement/functionMethod.kt

@@ -0,0 +1,8 @@
+// From KT-1254
+trait T {
+    fun Foo() : (String) -> Unit
+}
+
+class C : T {
+  <caret>
+}