Merge pull request scala#5632 from adriaanm/ticket/9114

SI-9114 Fix crasher in pattern matcher with type aliases

Author: adriaanm

src/reflect/scala/reflect/internal/Types.scala

@@ -3891,7 +3891,7 @@ trait Types
    *        any corresponding non-variant type arguments of bt1 and bt2 are the same
    */
   def isPopulated(tp1: Type, tp2: Type): Boolean = {
-    def isConsistent(tp1: Type, tp2: Type): Boolean = (tp1, tp2) match {
+    def isConsistent(tp1: Type, tp2: Type): Boolean = (tp1.dealias, tp2.dealias) match {
       case (TypeRef(pre1, sym1, args1), TypeRef(pre2, sym2, args2)) =>
         assert(sym1 == sym2, (sym1, sym2))
         (    pre1 =:= pre2

test/files/run/t9114.scala

@@ -0,0 +1,31 @@
+import annotation.unchecked
+
+class Test {
+  trait Two[A, B]
+  type One[A] = Two[A,A]
+  class View extends One[Any]
+
+  def checkAny(x: Some[One[Any]]) = x match { // okay
+    case Some(_: View) => true
+    case _ => false
+  }
+  def checkAbstract[A](x: Some[One[A]]) = x match { // okay
+    case Some(_: View) => true
+    case _ => false
+  }
+
+  def checkExistential(x: Some[One[_]]) = x match {
+    case Some(_: View) => true // compiler crash
+    case _ => false
+  }
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val t1 = new Test
+    val t2 = new Test
+    assert(t1.checkAny(Some(new t1.View)))
+    assert(t1.checkAbstract(Some(new t1.View)))
+    assert(t1.checkExistential(Some(new t1.View)))
+  }
+}