Fix named parameters handling of values that are falsy in JS.

compiler/java/com/google/dart/compiler/util/AstUtil.java

 // Copyright (c) 2011, 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.
 
 package com.google.dart.compiler.util;
 
 import com.google.dart.compiler.InternalCompilerException;
 import com.google.dart.compiler.backend.js.ast.JsArrayAccess;
 import com.google.dart.compiler.backend.js.ast.JsBinaryOperation;
 import com.google.dart.compiler.backend.js.ast.JsBinaryOperator;
@@ skipping 48 matching lines @@
   }
 
   public static JsNameRef newNameRef(JsExpression qualifier, String prop) {
     JsNameRef nameRef = new JsNameRef(prop);
     if (qualifier != null) {
       nameRef.setQualifier(qualifier);
     }
     return nameRef;
   }
 
+  public static JsNameRef nameref(SourceInfo info, JsName qualifier, JsName prop) {
+    JsNameRef nameRef = new JsNameRef(prop);
+    if (qualifier != null) {
+      nameRef.setQualifier(qualifier.makeRef());
+    }
+    nameRef.setSourceRef(info);
+    return nameRef;
+  }
+
   public static JsNameRef newNameRef(JsExpression qualifier, JsName prop) {
     JsNameRef nameRef = new JsNameRef(prop);
     if (qualifier != null) {
       nameRef.setQualifier(qualifier);
     }
     return nameRef;
   }
 
   public static JsNameRef newPrototypeNameRef(JsExpression qualifier) {
     return newNameRef(qualifier, "prototype");
@@ skipping 88 matching lines @@
       }
     }
     fn.setBody(newBlock(stmts));
     return fn;
   }
 
   public static JsInvocation call(SourceInfo src, JsExpression target, JsExpression ... params) {
     return (JsInvocation) newInvocation(target, params).setSourceRef(src);
   }
 
-  public static JsExpression comma(SourceInfo src, JsExpression op1, JsExpression op2) {
-    return new JsBinaryOperation(JsBinaryOperator.COMMA, op1, op2).setSourceRef(src);
+  public static JsBinaryOperation comma(SourceInfo src, JsExpression op1, JsExpression op2) {
+    return (JsBinaryOperation)new JsBinaryOperation(JsBinaryOperator.COMMA, op1, op2)
+       .setSourceRef(src);
   }
 
   public static JsNameRef nameref(SourceInfo src, String name) {
     return (JsNameRef) new JsNameRef(name).setSourceRef(src);
   }
 
   public static JsNameRef nameref(SourceInfo src, JsName qualifier, String prop) {
     return AstUtil.nameref(src, qualifier.makeRef().setSourceRef(src), prop);
   }
 
   public static JsNameRef nameref(SourceInfo src, JsExpression qualifier, String prop) {
     return (JsNameRef) newNameRef(qualifier, prop).setSourceRef(src);
   }
 
   public static JsExpression assign(SourceInfo src, JsNameRef op1, JsExpression op2) {
     return newAssignment(op1, op2).setSourceRef(src);
   }
 
   public static JsExpression neq(SourceInfo src, JsExpression op1, JsExpression op2) {
     return new JsBinaryOperation(JsBinaryOperator.NEQ, op1, op2).setSourceRef(src);
   }
 
   public static JsExpression not(SourceInfo src, JsExpression op1) {
     return new JsPrefixOperation(JsUnaryOperator.NOT, op1).setSourceRef(src);
   }
 
+  public static JsExpression preinc(SourceInfo src, JsExpression op1) {
+    return new JsPrefixOperation(JsUnaryOperator.INC, op1).setSourceRef(src);
+  }
+
   public static JsExpression and(SourceInfo src, JsExpression op1, JsExpression op2) {
-    return new JsBinaryOperation(JsBinaryOperator.AND, op1, op2);
+    return new JsBinaryOperation(JsBinaryOperator.AND, op1, op2).setSourceRef(src);
+  }
+
+  public static JsExpression in(SourceInfo src, JsExpression propName, JsExpression obj) {
+    return new JsBinaryOperation(JsBinaryOperator.INOP, propName, obj).setSourceRef(src);
   }
 }