Check compiler exitCode.

sdk/lib/_internal/compiler/implementation/util/util.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.
 
 library dart2js.util;
 
 import "dart:collection";
 import 'util_implementation.dart';
 import 'characters.dart';
 
@@ skipping 19 matching lines @@
 }
 
 const Spannable CURRENT_ELEMENT_SPANNABLE =
     const _SpannableSentinel("Current element");
 
 class SpannableAssertionFailure {
   final Spannable node;
   final String message;
   SpannableAssertionFailure(this.node, this.message);
 
-  String toString() => 'Compiler crashed: $message';
+  String toString() => 'Assertion failure: $message';
 }
 
 /**
  * Helper method for printing stack traces for debugging.
  *
  * [message] is printed as the header of the stack trace.
  *
  * If [condition] is provided, the stack trace is only printed if [condition]
  * returns [:true:] on the stack trace text. This can be used to filter the
  * printed stack traces based on their content. For instance only print stack
@@ skipping 232 matching lines @@
   }
   buffer.write(string);
 }
 
 int computeHashCode(part1, [part2, part3, part4]) {
   return (part1.hashCode
           ^ part2.hashCode
           ^ part3.hashCode
           ^ part4.hashCode) & 0x3fffffff;
 }