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 236 matching lines @@
             emittedArgumentCount != 4) ||
         (className == JavaScriptMapConstant.DART_GENERAL_CLASS &&
             emittedArgumentCount != 1)) {
       reporter.internalError(classElement,
           "Compiler and ${className} disagree on number of fields.");
     }
 
     jsAst.Expression constructor =
         backend.emitter.constructorAccess(classElement);
     jsAst.Expression value = new jsAst.New(constructor, arguments);
+    // Fix. Add an argument.

[Siggi Cherem (dart-lang), 2016/08/19 16:39:46]

did you indent to fix this one with this CL too?

     return maybeAddTypeArguments(constant.type, value);
   }
 
   JavaScriptBackend get backend => compiler.backend;
 
   jsAst.PropertyAccess getHelperProperty(Element helper) {
     return backend.emitter.staticFunctionAccess(helper);
   }
 
   @override
@@ skipping 33 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.classNeedsRti(constant.type.element)) {
+      fields.add(_reifiedTypeArguments(constant.type));
+    }
     jsAst.New instantiation = new jsAst.New(constructor, fields);
-    return maybeAddTypeArguments(constant.type, instantiation);
+    return instantiation;
   }
 
   String stripComments(String rawJavaScript) {
     return rawJavaScript.replaceAll(COMMENT_RE, '');
   }
 
   jsAst.Expression maybeAddTypeArguments(
       InterfaceType type, jsAst.Expression value) {
     if (type is InterfaceType &&
         !type.treatAsRaw &&
         backend.classNeedsRti(type.element)) {
-      InterfaceType interface = type;
-      RuntimeTypesEncoder rtiEncoder = backend.rtiEncoder;
-      Iterable<jsAst.Expression> arguments = interface.typeArguments.map(
-          (DartType type) =>
-              rtiEncoder.getTypeRepresentationWithPlaceholders(type, (_) {}));
-      jsAst.Expression argumentList =
-          new jsAst.ArrayInitializer(arguments.toList());
       return new jsAst.Call(
           getHelperProperty(backend.helpers.setRuntimeTypeInfo),
-          [value, argumentList]);
+          [value, _reifiedTypeArguments(type)]);
     }
     return value;
   }
 
+  jsAst.Expression _reifiedTypeArguments(InterfaceType type) {
+    RuntimeTypesEncoder rtiEncoder = backend.rtiEncoder;
+    Iterable<jsAst.Expression> arguments = type.typeArguments.map(
+        (DartType type) =>
+        rtiEncoder.getTypeRepresentationWithPlaceholders(type, (_) {}));
+    jsAst.Expression argumentList =
+        new jsAst.ArrayInitializer(arguments.toList());
+    return argumentList;
+  }
+
   @override
   jsAst.Expression visitDeferred(DeferredConstantValue constant, [_]) {
     return constantReferenceGenerator(constant.referenced);
   }
 }