Fix tests to conform to new behavior

Author: odersky

tests/neg/overrides.scala

@@ -79,27 +79,6 @@ class X3 {
   override type T = A1 // error: overrides nothing
 }
 
-package p3 {
-
-// Dotty change of rules: Toverrider#f does not
-// override TCommon#f, hence the accidental override rule
-// applies.
-trait TCommon {
-  def f: String
-}
-
-class C1 extends TCommon {
-  def f = "in C1"
-}
-
-trait TOverrider { this: TCommon =>
-  override def f = "in TOverrider"   // The overridden self-type member...
-}
-
-class C2 extends C1 with TOverrider  // ... fails to override, here. // error: accidental override
-
-}
-
 package p4 {
 
   abstract class C[T] { def head: T }

tests/pos/override-via-self.scala

@@ -0,0 +1,18 @@
+// Question: Does TOverrider#f override TCommon#f?
+// If not, the accidental override rule applies.
+// Dotty used to say no, but with the change to baseClasses in AndTypes says
+// yes. Not sure what the right answer is. But in any case we should
+// keep the test to notice if there's a difference in behavior.
+trait TCommon {
+  def f: String
+}
+class C1 extends TCommon {
+  def f = "in C1"
+}
+
+trait TOverrider { this: TCommon =>
+  override def f = "in TOverrider"   // The overridden self-type member...
+}
+
+class C2 extends C1 with TOverrider  // ... failed to override, here. But now it is OK.
+