Incorrect type parameter ascription when extending from nonpolymorphic trait with polymorphic grandparent class

[wiwa]

  class C[A]

  trait T extends C[Int]

  class D extends T

--- obtained
+++ expected
@@ -7,3 +7,3 @@
∙
-  class D extends T[Int]
+  class D extends T
 }

Basically, RscCompat will incorrectly ascribe type parameters to the extends trait. This also happens when C is abstract class but not when it's a trait.

[wiwa]

scalameta/scalameta#1887