Fix #10077: Add regression test

Author: OlivierBlanvillain

tests/pos/10077.scala

@@ -0,0 +1,13 @@
+trait T[F[_[_]]]
+
+type Inner[x] = [X[_]] =>> x match { case T[f] => f[X] }
+
+trait Monad[F[_]]
+type TMonad = T[Monad]
+
+trait U[T0]:
+  type T0_member = T0
+  def f(x: Inner[T0][List]): Unit
+
+class X extends U[T[Monad]]:
+  def f(x: Inner[T0_member][List]): Unit = ???