Handle symbol literals in closed_world2_test

pkg/compiler/lib/src/inferrer/builder.dart

 // Copyright (c) 2013, 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 simple_types_inferrer;
 
 import '../closure.dart' show ClosureClassMap;
 import '../common.dart';
 import '../common/names.dart' show Identifiers, Selectors;
 import '../compiler.dart' show Compiler;
@@ skipping 224 matching lines @@
   }
 
   TypeInformation visitLiteralNull(ast.LiteralNull node) {
     return types.nullType;
   }
 
   TypeInformation visitLiteralSymbol(ast.LiteralSymbol node) {
     // TODO(kasperl): We should be able to tell that the type of a literal
     // symbol is always a non-null exact symbol implementation -- not just
     // any non-null subtype of the symbol interface.
-    return types.nonNullSubtype(closedWorld.commonElements.symbolClass);
+    return types
+        .nonNullSubtype(closedWorld.commonElements.symbolImplementationClass);
   }
 
   @override
   void previsitDeferredAccess(ast.Send node, PrefixElement prefix, _) {
     // Deferred access does not affect inference.
   }
 
   TypeInformation handleTypeLiteralGet() {
     return types.typeType;
   }
@@ skipping 2691 matching lines @@
     Selector moveNextSelector = Selectors.moveNext;
     TypeMask moveNextMask = inTreeData.typeOfIteratorMoveNext(node);
 
     TypeInformation iteratorType = handleDynamicSend(node, iteratorSelector,
         iteratorMask, expressionType, new ArgumentsTypes.empty());
 
     return handleForInLoop(node, iteratorType, currentSelector, currentMask,
         moveNextSelector, moveNextMask);
   }
 }