Fixed needs outer test

Author: odersky

src/dotty/tools/dotc/transform/ExplicitOuter.scala

@@ -137,7 +137,7 @@ object ExplicitOuter {
     nme.OUTER.expandedName(cls)
 
   /** Class needs an outer pointer, provided there is a reference to an outer this in it. */
-  private def needsOuterIfReferenced(cls: ClassSymbol)(implicit ctx: Context): Boolean = !(
+  def needsOuterIfReferenced(cls: ClassSymbol)(implicit ctx: Context): Boolean = !(
     cls.isStatic ||
     cls.owner.enclosingClass.isStaticOwner ||
     cls.is(Interface)

src/dotty/tools/dotc/transform/PatternMatcher.scala

@@ -740,8 +740,9 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
         // See the test for SI-7214 for motivation for dealias. Later `treeCondStrategy#outerTest`
         // generates an outer test based on `patType.prefix` with automatically dealises.
         patType.dealias match {
-          case TypeRef(pre, name) =>
-            (pre ne NoType)// && isPopulated(copyTypeRef(patType, pre1, sym, args), selType)
+          case tref @ TypeRef(pre, name) =>
+            (pre ne NoPrefix) && tref.symbol.isClass &&
+            ExplicitOuter.needsOuterIfReferenced(tref.symbol.asClass)
           case _ =>
             false
         }