suggest only superclass elements for "super."

pkg/analysis_server/lib/src/services/completion/prefixed_element_contributor.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library services.completion.contributor.dart.invocation;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:analysis_server/src/services/completion/local_declaration_visitor.dart';
@@ skipping 55 matching lines @@
       node = (node as PropertyAccess).realTarget;
     }
     if (node is Identifier) {
       Element elem = node.bestElement;
       if (elem is ClassElement || elem is PrefixElement) {
         elem.accept(new _PrefixedIdentifierSuggestionBuilder(request));
         return new Future.value(true);
       }
     }
     if (node is Expression) {
-      InterfaceTypeSuggestionBuilder.suggestionsFor(request, node.bestType);
+      InterfaceTypeSuggestionBuilder.suggestionsFor(request, node.bestType,
+          isSuper: node is SuperExpression);
       return new Future.value(true);
     }
     return new Future.value(false);
   }
 }
 
 /**
  * A suggestion builder for 'this.' constructor arguments.
  */
 class _FieldFormalSuggestionBuilder implements SuggestionBuilder {
@@ skipping 338 matching lines @@
     }
     return new Future.value(false);
   }
 
   @override
   Future<bool> visitVariableElement(VariableElement element) {
     InterfaceTypeSuggestionBuilder.suggestionsFor(request, element.type);
     return new Future.value(true);
   }
 }