fix #27320, better DDC temp generation

pkg/dev_compiler/lib/src/js_ast/template.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.
 
 part of js_ast;
 
 class TemplateManager {
   Map<String, Template> expressionTemplates = new Map<String, Template>();
   Map<String, Template> statementTemplates = new Map<String, Template>();
 
@@ skipping 391 matching lines @@
     };
   }
 
   Instantiator visitFor(For node) {
     Instantiator makeInit = visitNullable(node.init);
     Instantiator makeCondition = visitNullable(node.condition);
     Instantiator makeUpdate = visitNullable(node.update);
     Instantiator makeBody = visit(node.body);
     return (arguments) {
       return new For(makeInit(arguments), makeCondition(arguments),
-          makeUpdate(arguments), makeBody(arguments));
+          makeUpdate(arguments)?.toVoidExpression(), makeBody(arguments));
     };
   }
 
   Instantiator visitForIn(ForIn node) {
     Instantiator makeLeftHandSide = visit(node.leftHandSide);
     Instantiator makeObject = visit(node.object);
     Instantiator makeBody = visit(node.body);
     return (arguments) {
       return new ForIn(makeLeftHandSide(arguments), makeObject(arguments),
           makeBody(arguments));
@@ skipping 30 matching lines @@
     };
   }
 
   Instantiator visitContinue(Continue node) =>
       (arguments) => new Continue(node.targetLabel);
 
   Instantiator visitBreak(Break node) =>
       (arguments) => new Break(node.targetLabel);
 
   Instantiator visitReturn(Return node) {
-    Instantiator makeExpression = visitNullable(node.value);
-    return (arguments) => new Return(makeExpression(arguments));
+    if (node.value == null) return (args) => new Return();
+    Instantiator makeExpression = visit(node.value);
+    return (args) => makeExpression(args).toReturn();
   }
 
   Instantiator visitDartYield(DartYield node) {
     Instantiator makeExpression = visit(node.expression);
     return (arguments) =>
         new DartYield(makeExpression(arguments), node.hasStar);
   }
 
   Instantiator visitThrow(Throw node) {
     Instantiator makeExpression = visit(node.expression);
@@ skipping 70 matching lines @@
       }
       return new VariableDeclarationList(node.keyword, declarations);
     };
   }
 
   Instantiator visitAssignment(Assignment node) {
     Instantiator makeLeftHandSide = visit(node.leftHandSide);
     String op = node.op;
     Instantiator makeValue = visitNullable(node.value);
     return (arguments) {
-      return new Assignment.compound(
-          makeLeftHandSide(arguments), op, makeValue(arguments));
+      return makeValue(arguments)
+          .toAssignExpression(makeLeftHandSide(arguments), op);
     };
   }
 
   Instantiator visitVariableInitialization(VariableInitialization node) {
     Instantiator makeDeclaration = visit(node.declaration);
     Instantiator makeValue = visitNullable(node.value);
     return (arguments) {
       return new VariableInitialization(
           makeDeclaration(arguments), makeValue(arguments));
     };
@@ skipping 342 matching lines @@
     if (count != before) containsInterpolatedNode.add(node);
     return null;
   }
 
   visitInterpolatedNode(InterpolatedNode node) {
     containsInterpolatedNode.add(node);
     if (node.isNamed) holeNames.add(node.nameOrPosition);
     ++count;
   }
 }