Fix mixin resolution order when multiple mixins present.

pkg/analyzer/lib/src/generated/resolver.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 engine.resolver;
 
 import "dart:math" as math;
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/utilities_collection.dart';
@@ skipping 5942 matching lines @@
         }
       } else {
         // This case happens only when the superclass was previously visited and
         // not in the lookup, meaning this is meant to shorten the compute for
         // recursive cases.
         _classLookup[superclassElt] = resultMap;
         return resultMap;
       }
     }
     //
-    // Include the members from the mixins in the resultMap
+    // Include the members from the mixins in the resultMap.  If there are
+    // multiple mixins, visit them in the order listed so that methods in later
+    // mixins will overwrite identically-named methods in earlier mixins.
     //
     List<InterfaceType> mixins = classElt.mixins;
-    for (int i = mixins.length - 1; i >= 0; i--) {
-      ClassElement mixinElement = mixins[i].element;
+    for (InterfaceType mixin in mixins) {
+      ClassElement mixinElement = mixin.element;
       if (mixinElement != null) {
         if (!visitedClasses.contains(mixinElement)) {
           visitedClasses.add(mixinElement);
           try {
             MemberMap map =
                 new MemberMap.con2(_computeClassChainLookupMap(mixinElement, visitedClasses));
             //
             // Substitute the super types down the hierarchy.
             //
-            _substituteTypeParametersDownHierarchy(mixins[i], map);
+            _substituteTypeParametersDownHierarchy(mixin, map);
             //
             // Include the members from the superclass in the resultMap.
             //
-            _recordMapWithClassMembers(map, mixins[i], false);
+            _recordMapWithClassMembers(map, mixin, false);
             //
             // Add the members from map into result map.
             //
             for (int j = 0; j < map.size; j++) {
               String key = map.getKey(j);
               ExecutableElement value = map.getValue(j);
               if (key != null) {
                 if (resultMap.get(key) == null ||
                     (resultMap.get(key) != null && !_isAbstract(value))) {
                   resultMap.put(key, value);
@@ skipping 9466 matching lines @@
    * library.
    */
   final HashSet<String> members = new HashSet<String>();
 
   /**
    * Names of resolved or unresolved class members that are read in the
    * library.
    */
   final HashSet<String> readMembers = new HashSet<String>();
 }