Fix #9107: Add regression test

Author: OlivierBlanvillain

tests/neg/9107.scala

@@ -0,0 +1,14 @@
+trait M[F[_]]
+trait Inv[T]
+
+object Test {
+  def ev[X] = implicitly[
+    (X match { case Inv[t] => Int }) =:=
+    (X match { case Inv[t] => t })
+  ] // error
+
+  def ev2[X] = implicitly[
+    (M[[t] =>> runtime.MatchCase[Inv[t], Int]])  =:=
+    (M[[t] =>> runtime.MatchCase[Inv[t], t]])
+  ] // error
+}