Making save a little faster:

compiler/java/com/google/dart/compiler/ast/DartFunction.java

 // 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.
 
 package com.google.dart.compiler.ast;
 
 import java.util.List;
 
 /**
  * Represents a Dart function.
  */
 public class DartFunction extends DartNode {
 
   private final NodeList<DartParameter> parameters = NodeList.create(this);
   private final int parametersOptionalOpen;
   private final int parametersOptionalClose;
   private final int parametersCloseParen;
   private DartBlock body;
   private DartTypeNode returnTypeNode;
 
   public DartFunction(List<DartParameter> parameters, int parametersOptionalOpen,
       int parametersOptionalClose, int parametersCloseParen, DartBlock body,
       DartTypeNode returnTypeNode) {
     this.parametersOptionalOpen = parametersOptionalOpen;
     this.parametersOptionalClose = parametersOptionalClose;
-    this.parameters.addAll(parameters);
+    if (parameters != null && !parameters.isEmpty()) {
+      this.parameters.addAll(parameters);
+    }
     this.parametersCloseParen = parametersCloseParen;
     this.body = becomeParentOf(body);
     this.returnTypeNode = becomeParentOf(returnTypeNode);
   }
 
   public DartBlock getBody() {
     return body;
   }
 
   public List<DartParameter> getParameters() {
@@ skipping 21 matching lines @@
     parameters.accept(visitor);
     safelyVisitChild(body, visitor);
     safelyVisitChild(returnTypeNode, visitor);
   }
 
   @Override
   public <R> R accept(ASTVisitor<R> visitor) {
     return visitor.visitFunction(this);
   }
 }