Add command-line parameter enabling assert messages.

pkg/compiler/lib/src/scanner/parser.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.
 
 part of scanner;
 
 class FormalParameterType {
   final String type;
   const FormalParameterType(this.type);
   bool get isRequired => this == REQUIRED;
@@ skipping 25 matching lines @@
  * suffix can be one of "opt", or "star". "opt" means zero or one
  * matches, "star" means zero or more matches. For example,
  * [parseMetadataStar] corresponds to this grammar snippet: [:
  * metadata* :], and [parseTypeOpt] corresponds to: [: type? :].
  */
 class Parser {
   final Listener listener;
   bool mayParseFunctionExpressions = true;
   bool yieldIsKeyword;
   bool awaitIsKeyword;
+  bool allowAssertMessage;
 
   Parser(this.listener,
-         {this.yieldIsKeyword: false, this.awaitIsKeyword: false});
+         {this.yieldIsKeyword: false,
+          this.awaitIsKeyword: false,
+          this.allowAssertMessage: false}) {
+    print("PARSER: $allowAssertMessage");
+    if (!allowAssertMessage) {
+      try {throw 0;} catch(e,s) {print(s);}
+    }
+  }
 
   Token parseUnit(Token token) {
     listener.beginCompilationUnit(token);
     int count = 0;
     while (!identical(token.kind, EOF_TOKEN)) {
       token = parseTopLevelDeclaration(token);
       listener.endTopLevelDeclaration(token);
       count++;
     }
     listener.endCompilationUnit(count, token);
@@ skipping 2608 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }