Add support for assert statements with messages to the analyzer.

pkg/analyzer/lib/src/generated/error.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.
 
 library engine.error;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/ast.dart' show AstNode;
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 1160 matching lines @@
    * Parameters:
    * 0: the name of the type that cannot be extended
    *
    * See [IMPLEMENTS_DEFERRED_CLASS], and [MIXIN_DEFERRED_CLASS].
    */
   static const CompileTimeErrorCode EXTENDS_DEFERRED_CLASS =
       const CompileTimeErrorCode('EXTENDS_DEFERRED_CLASS',
           "This class cannot extend the deferred class '{0}'");
 
   /**
+   * DEP 37 extends the syntax for assert() to allow a second "message"
+   * argument.  We issue this error if the user tries to supply a "message"
+   * argument but the DEP is not enabled.
+   */
+  static const CompileTimeErrorCode EXTRA_ARGUMENT_TO_ASSERT =
+      const CompileTimeErrorCode('EXTRA_ARGUMENT_TO_ASSERT',
+          "Assertions only accept a single argument");
+
+  /**
    * 12.14.2 Binding Actuals to Formals: It is a static warning if <i>m &lt;
    * h</i> or if <i>m &gt; n</i>.
    *
    * 12.11.2 Const: It is a compile-time error if evaluation of a constant
    * object results in an uncaught exception being thrown.
    *
    * Parameters:
    * 0: the maximum number of positional arguments
    * 1: the actual number of positional arguments given
    */
@@ skipping 4462 matching lines @@
    * Initialize a newly created error code to have the given [name].
    */
   const TodoCode(String name) : super(name, "{0}");
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.INFO;
 
   @override
   ErrorType get type => ErrorType.TODO;
 }