Revert "Implement override checks."

lib/compiler/implementation/resolver.dart

Index: lib/compiler/implementation/resolver.dart
diff --git a/lib/compiler/implementation/resolver.dart b/lib/compiler/implementation/resolver.dart
index fce5ad0efb3ebb8192a872983139ed7f183b6632..f2432c35b0c9ac53b81d9607f5c45f46e25ede72 100644
--- a/lib/compiler/implementation/resolver.dart
+++ b/lib/compiler/implementation/resolver.dart
@@ -229,100 +229,9 @@ class ResolverTask extends CompilerTask {
         new ClassResolverVisitor(compiler, element.getLibrary(), element);
       visitor.visit(tree);
       element.isResolved = true;
-
-      while (!toResolve.isEmpty()) {
-        ClassElement classElement = toResolve.removeFirst();
-        classElement.ensureResolved(compiler);
-      }
-
-      checkMembers(element);
     });
   }
 
-  checkMembers(ClassElement cls) {
-    if (cls === compiler.objectClass) return;
-    cls.forEachMember((holder, member) {
-      checkAbstractField(member);
-      checkValidOverride(member, cls.lookupSuperMember(member.name));
-    });
-  }
-
-  void checkAbstractField(Element member) {
-    if (member is !AbstractFieldElement) return;
-    if (member.getter === null) return;
-    if (member.setter === null) return;
-    int getterFlags = member.getter.modifiers.flags | Modifiers.FLAG_ABSTRACT;
-    int setterFlags = member.setter.modifiers.flags | Modifiers.FLAG_ABSTRACT;
-    if (getterFlags !== setterFlags) {
-      final mismatchedFlags =
-        new Modifiers.withFlags(null, getterFlags ^ setterFlags);
-      compiler.reportMessage(
-          compiler.spanFromElement(member.getter),
-          MessageKind.GETTER_MISMATCH.error([mismatchedFlags]),
-          api.Diagnostic.ERROR);
-      compiler.reportMessage(
-          compiler.spanFromElement(member.setter),
-          MessageKind.SETTER_MISMATCH.error([mismatchedFlags]),
-          api.Diagnostic.ERROR);
-    }
-  }
-
-  reportErrorWithContext(Element errorneousElement,
-                         MessageKind errorMessage,
-                         Element contextElement,
-                         MessageKind contextMessage) {
-    compiler.reportMessage(
-        compiler.spanFromElement(errorneousElement),
-        errorMessage.error([contextElement.name,
-                            contextElement.getEnclosingClass().name]),
-        api.Diagnostic.ERROR);
-    compiler.reportMessage(
-        compiler.spanFromElement(contextElement),
-        contextMessage.error(),
-        api.Diagnostic.INFO);
-  }
-
-
-  void checkValidOverride(Element member, Element superMember) {
-    if (superMember === null) return;
-    if (member.modifiers.isStatic()) {
-      reportErrorWithContext(
-          member, MessageKind.NO_STATIC_OVERRIDE,
-          superMember, MessageKind.NO_STATIC_OVERRIDE_CONT);
-    } else {
-      FunctionElement superFunction = superMember.asFunctionElement();
-      FunctionElement function = member.asFunctionElement();
-      if (superFunction === null || superFunction.isAccessor()) {
-        // Field or accessor in super.
-        if (function !== null && !function.isAccessor()) {
-          // But a plain method in this class.
-          reportErrorWithContext(
-              member, MessageKind.CANNOT_OVERRIDE_FIELD_WITH_METHOD,
-              superMember, MessageKind.CANNOT_OVERRIDE_FIELD_WITH_METHOD_CONT);
-        }
-      } else {
-        // Instance method in super.
-        if (function === null || function.isAccessor()) {
-          // But a field (or accessor) in this class.
-          reportErrorWithContext(
-              member, MessageKind.CANNOT_OVERRIDE_METHOD_WITH_FIELD,
-              superMember, MessageKind.CANNOT_OVERRIDE_METHOD_WITH_FIELD_CONT);
-        } else {
-          // Both are plain instance methods.
-          if (superFunction.requiredParameterCount(compiler) !=
-              function.requiredParameterCount(compiler)) {
-          reportErrorWithContext(
-              member,
-              MessageKind.BAD_ARITY_OVERRIDE,
-              superMember,
-              MessageKind.BAD_ARITY_OVERRIDE_CONT);
-          }
-          // TODO(ahe): Check optional parameters.
-        }
-      }
-    }
-  }
-
   FunctionSignature resolveSignature(FunctionElement element) {
     return compiler.withCurrentElement(element, () {
       FunctionExpression node =