Issue 25558. Report an error, but don't crash when AST it too deep.

pkg/analyzer/lib/src/dart/error/syntactic_errors.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.
 
 /**
  * The errors produced during syntactic analysis (scanning and parsing).
  */
 library analyzer.src.dart.error.syntactic_errors;
 
 import 'package:analyzer/error/error.dart';
@@ skipping 816 matching lines @@
           'REDIRECTION_IN_NON_FACTORY_CONSTRUCTOR',
           "Only factory constructor can specify '=' redirection.",
           "Try making this a factory constructor, or "
           "not making this a redirecting constructor.");
 
   static const ParserErrorCode SETTER_IN_FUNCTION = const ParserErrorCode(
       'SETTER_IN_FUNCTION',
       "Setters can't be defined within methods or functions.",
       "Try moving the setter outside the method or function.");
 
+  static const ParserErrorCode STACK_OVERFLOW = const ParserErrorCode(
+      'STACK_OVERFLOW',
+      "The file has too many nested expressions or statements.",
+      "Try simplifying the code.");
+
   static const ParserErrorCode STATIC_AFTER_CONST = const ParserErrorCode(
       'STATIC_AFTER_CONST',
       "The modifier 'static' should be before the modifier 'const'.",
       "Try re-ordering the modifiers.");
 
   static const ParserErrorCode STATIC_AFTER_FINAL = const ParserErrorCode(
       'STATIC_AFTER_FINAL',
       "The modifier 'static' should be before the modifier 'final'.",
       "Try re-ordering the modifiers.");
 
@@ skipping 150 matching lines @@
    */
   const ParserErrorCode(String name, String message, [String correction])
       : super(name, message, correction);
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.ERROR;
 
   @override
   ErrorType get type => ErrorType.SYNTACTIC_ERROR;
 }