Fix mixin resolution order when multiple mixins present.

pkg/analysis_server/test/services/completion/local_computer_test.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 test.services.completion.dart.local;
 
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:analysis_server/src/services/completion/local_computer.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 43 matching lines @@
       String declaringType, String returnType, {int relevance:
       COMPLETION_RELEVANCE_DEFAULT, bool isDeprecated: false}) {
     return assertSuggestMethod(
         name,
         declaringType,
         returnType,
         relevance: relevance,
         isDeprecated: isDeprecated);
   }
 
+  fail_mixin_ordering() {
+    // TODO(paulberry): Duplicates aren't being removed, so we see both M1.m()
+    // and M2.m().
+    addTestSource('''
+class B {}
+class M1 {
+  void m() {}
+}
+class M2 {
+  void m() {}
+}
+class C extends B with M1, M2 {
+  void f() {
+    ^
+  }
+}
+''');
+    expect(computeFast(), isTrue);
+    assertSuggestMethod('m', 'M2', 'void');
+  }
+
   @override
   void setUpComputer() {
     computer = new LocalComputer();
   }
 
   test_break_ignores_outer_functions_using_closure() {
     addTestSource('''
 void main() {
   foo: while (true) {
     var f = () {
@@ skipping 485 matching lines @@
     CompletionSuggestion suggestion = assertSuggestMethod('m', 'A', 'void');
     expect(suggestion.parameterNames, hasLength(2));
     expect(suggestion.parameterNames[0], 'x');
     expect(suggestion.parameterTypes[0], 'dynamic');
     expect(suggestion.parameterNames[1], 'y');
     expect(suggestion.parameterTypes[1], 'int');
     expect(suggestion.requiredParameterCount, 2);
     expect(suggestion.hasNamedParameters, false);
   }
 }