dart2js: Pass type information to constructor rather than add later.

pkg/compiler/lib/src/js_backend/constant_emitter.dart

 // Copyright (c) 2012, 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.
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../io/code_output.dart';
@@ skipping 233 matching lines @@
     if ((className == JavaScriptMapConstant.DART_STRING_CLASS &&
             emittedArgumentCount != 3) ||
         (className == JavaScriptMapConstant.DART_PROTO_CLASS &&
             emittedArgumentCount != 4) ||
         (className == JavaScriptMapConstant.DART_GENERAL_CLASS &&
             emittedArgumentCount != 1)) {
       reporter.internalError(classElement,
           "Compiler and ${className} disagree on number of fields.");
     }
 
+    if (backend.classNeedsRtiField(classElement)) {
+      arguments.add(_reifiedTypeArguments(constant.type));
+    }
+
     jsAst.Expression constructor =
         backend.emitter.constructorAccess(classElement);
     jsAst.Expression value = new jsAst.New(constructor, arguments);
-    return maybeAddTypeArguments(constant.type, value);
+    return value;
   }
 
   JavaScriptBackend get backend => compiler.backend;
 
   jsAst.PropertyAccess getHelperProperty(Element helper) {
     return backend.emitter.staticFunctionAccess(helper);
   }
 
   @override
   jsAst.Expression visitType(TypeConstantValue constant, [_]) {
@@ skipping 32 matching lines @@
       StringConstantValue str = constant.fields.values.single;
       String value = str.primitiveValue.slowToString();
       return new jsAst.LiteralExpression(stripComments(value));
     }
     jsAst.Expression constructor =
         backend.emitter.constructorAccess(constant.type.element);
     List<jsAst.Expression> fields = <jsAst.Expression>[];
     element.forEachInstanceField((_, FieldElement field) {
       fields.add(constantReferenceGenerator(constant.fields[field]));
     }, includeSuperAndInjectedMembers: true);
+    if (backend.classNeedsRtiField(constant.type.element)) {
+      fields.add(_reifiedTypeArguments(constant.type));
+    }
     jsAst.New instantiation = new jsAst.New(constructor, fields);
     return maybeAddTypeArguments(constant.type, instantiation);
   }
 
   String stripComments(String rawJavaScript) {
     return rawJavaScript.replaceAll(COMMENT_RE, '');
   }
 
   jsAst.Expression maybeAddTypeArguments(
       InterfaceType type, jsAst.Expression value) {
@@ skipping 22 matching lines @@
       arguments.add(rtiEncoder.getTypeRepresentation(argument, unexpected));
     }
     return new jsAst.ArrayInitializer(arguments);
   }
 
   @override
   jsAst.Expression visitDeferred(DeferredConstantValue constant, [_]) {
     return constantReferenceGenerator(constant.referenced);
   }
 }