relaxed rule requiring `override` modifiers so ...

relaxed rule requiring `override` modifiers so that it's OK if self type
contains overridden symbol.

1 files changed, 14 insertions, 10 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index fbe01c7fac..c4a3981a51 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -453,21 +453,25 @@ abstract class RefChecks extends InfoTransform {
         if (!(clazz hasFlag ABSTRACT)) checkNoAbstractDecls(clazz)
       }
 
-      /** Does there exists a symbol declared in class `inclazz` with name `name` and
-       *  whose type seen as a member of `class.thisType` matches `tpe`?
+      /** Returns whether there is a symbol declared in class `inclazz`
+       *  (which must be different from `clazz`) whose name and type
+       *  seen as a member of `class.thisType` matches `member`'s.
        */
-      def hasMatchingSym(inclazz: Symbol, name: Name, tpe: Type): Boolean =
-        inclazz.info.nonPrivateDecl(name).filter(sym =>
-          !sym.isTerm || (tpe matches clazz.thisType.memberType(sym))) != NoSymbol
+      def hasMatchingSym(inclazz: Symbol, member: Symbol): Boolean =
+        inclazz != clazz && {
+          val isVarargs = hasRepeatedParam(member.tpe)
+          inclazz.info.nonPrivateDecl(member.name).filter { sym =>
+            !sym.isTerm || {
+              val symtpe = clazz.thisType.memberType(sym)
+              (member.tpe matches symtpe) || isVarargs && (toJavaRepeatedParam(member.tpe) matches symtpe)
+            }
+          } != NoSymbol
+        }
 
       // 4. Check that every defined member with an `override' modifier overrides some other member.
       for (member <- clazz.info.decls.toList)
         if ((member hasFlag (OVERRIDE | ABSOVERRIDE)) &&
-            !(clazz.ancestors exists { bc =>
-               hasMatchingSym(bc, member.name, member.tpe) ||
-               hasRepeatedParam(member.tpe) &&
-               hasMatchingSym(bc, member.name, toJavaRepeatedParam(member.tpe))
-            })) {
+            !(clazz.thisType.baseClasses exists (hasMatchingSym(_, member)))) {
           // for (bc <- clazz.info.baseClasses.tail) Console.println("" + bc + " has " + bc.info.decl(member.name) + ":" + bc.info.decl(member.name).tpe);//DEBUG
           unit.error(member.pos, member.toString() + " overrides nothing");
           member resetFlag OVERRIDE