Fix kernel/visitor_test

tests/compiler/dart2js/kernel/class_hierarchy_test.dart

+// Copyright (c) 2016, 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.
+
+/// Test that the dart2js copy of [KernelVisitor] generates the expected class
+/// hierarchy.
+
+import 'package:compiler/src/compiler.dart' show Compiler;
+import 'package:compiler/src/elements/elements.dart';
+import 'package:compiler/src/js_backend/backend.dart' show JavaScriptBackend;
+import 'package:compiler/src/commandline_options.dart' show Flags;
+import 'package:kernel/ast.dart' as ir;
+import 'package:kernel/class_hierarchy.dart';
+import 'package:test/test.dart';
+
+import '../memory_compiler.dart';
+
+main(List<String> arguments) {
+  Compiler compiler = compilerFor(memorySourceFiles: {
+    'main.dart': '''
+      class S {
+        sMethod() {}
+      }
+      class M {
+        mMethod() {}
+      }
+      class C extends S with M {
+        cMethod() {}
+      }
+      main() {}
+      '''
+  }, options: [
+    Flags.analyzeOnly,
+    Flags.analyzeMain,
+    Flags.useKernel
+  ]);
+  test('mixin', () async {
+    Uri mainUri = Uri.parse('memory:main.dart');
+    LibraryElement library = await compiler.analyzeUri(mainUri);
+    JavaScriptBackend backend = compiler.backend;
+    ir.Program program = backend.kernelTask.buildProgram(library);
+    ClassHierarchy hierarchy = new ClassHierarchy(program);
+
+    ir.Class getClass(String name) {
+      for (ir.Class cls in hierarchy.classes) {
+        if (cls.enclosingLibrary.importUri == mainUri && cls.name == name) {
+          if (arguments.contains('-v')) {
+            print('$cls');
+            print(' dispatch targets:');
+            hierarchy
+                .getDispatchTargets(cls)
+                .forEach((member) => print('  $member'));
+          }
+          return cls;
+        }
+      }
+      fail('Class $name not found.');
+    }
+
+    ir.Class classS = getClass('S');
+    ir.Class classM = getClass('M');
+    ir.Class classC = getClass('C');
+
+    void checkInheritance(ir.Class superClass, ir.Class subClass) {
+      for (ir.Member member in hierarchy.getDispatchTargets(superClass)) {
+        expect(
+            hierarchy.getDispatchTarget(subClass, member.name), equals(member),
+            reason: 'Unexpected dispatch target for ${member.name} '
+                'in $subClass');
+      }
+    }
+
+    checkInheritance(classS, classC);
+    checkInheritance(classM, classC);
+  });
+}