Land Alexander's change that turns assert into a keyword.

lib/compiler/implementation/scanner/keyword.dart

 // 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.
 
 /**
  * A keyword in the Dart programming language.
  */
 class Keyword implements SourceString {
   static const List<Keyword> values = const <Keyword> [
+      const Keyword("assert"),
       const Keyword("break"),
       const Keyword("case"),
       const Keyword("catch"),
       const Keyword("class"),
       const Keyword("const"),
       const Keyword("continue"),
       const Keyword("default"),
       const Keyword("do"),
       const Keyword("else"),
       const Keyword("extends"),
@@ skipping 15 matching lines @@
       const Keyword("var"),
       const Keyword("void"),
       const Keyword("while"),
 
       // TODO(ahe): Don't think this is a reserved word.
       // See: http://dartbug.com/5579
       const Keyword("is", info: IS_INFO),
 
       const Keyword("abstract", isBuiltIn: true),
       const Keyword("as", info: AS_INFO, isBuiltIn: true),
-      const Keyword("assert", isBuiltIn: true),
       const Keyword("dynamic", isBuiltIn: true),
       const Keyword("export", isBuiltIn: true),
       const Keyword("external", isBuiltIn: true),
       const Keyword("factory", isBuiltIn: true),
       const Keyword("get", isBuiltIn: true),
       const Keyword("implements", isBuiltIn: true),
       const Keyword("import", isBuiltIn: true),
       const Keyword("interface", isBuiltIn: true),
       const Keyword("library", isBuiltIn: true),
       const Keyword("operator", isBuiltIn: true),
@@ skipping 166 matching lines @@
   final Keyword keyword;
 
   LeafKeywordState(String syntax) : keyword = Keyword.keywords[syntax];
 
   bool isLeaf() => true;
 
   KeywordState next(int c) => null;
 
   String toString() => keyword.syntax;
 }