Use failedAt in more places (misc)

pkg/compiler/lib/src/diagnostics/messages.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.
 
 /// The messages in this file should follow the [Guide for Writing
 /// Diagnostics](../../../../front_end/lib/src/fasta/diagnostics.md).
 ///
 /// Other things to keep in mind:
 ///
 /// An INFO message should always be preceded by a non-INFO message, and the
 /// INFO messages are additional details about the preceding non-INFO
 /// message. For example, consider duplicated elements. First report a WARNING
 /// or ERROR about the duplicated element, and then report an INFO about the
 /// location of the existing element.
 library dart2js.messages;
 
 import 'package:front_end/src/fasta/scanner.dart' show ErrorToken, Token;
 import 'generated/shared_messages.dart' as shared_messages;
-import 'invariant.dart' show invariant;
+import 'invariant.dart' show failedAt;
 import 'spannable.dart' show CURRENT_ELEMENT_SPANNABLE;
 
 const DONT_KNOW_HOW_TO_FIX = "Computer says no!";
 
 /// Keys for the [MessageTemplate]s.
 enum MessageKind {
   ABSTRACT_CLASS_INSTANTIATION,
   ABSTRACT_GETTER,
   ABSTRACT_METHOD,
   ABSTRACT_SETTER,
@@ skipping 3725 matching lines @@
   }
 
   MessageKind get kind => template.kind;
 
   String computeMessage() {
     if (message == null) {
       message = template.template;
       arguments.forEach((key, value) {
         message = message.replaceAll('#{${key}}', convertToString(value));
       });
-      assert(invariant(
-          CURRENT_ELEMENT_SPANNABLE,
+      assert(
           kind == MessageKind.GENERIC ||
               !message.contains(new RegExp(r'#\{.+\}')),
-          message: 'Missing arguments in error message: "$message"'));
+          failedAt(CURRENT_ELEMENT_SPANNABLE,
+              'Missing arguments in error message: "$message"'));
       if (!terse && template.hasHowToFix) {
         String howToFix = template.howToFix;
         arguments.forEach((key, value) {
           howToFix = howToFix.replaceAll('#{${key}}', convertToString(value));
         });
         message = '$message\n$howToFix';
       }
     }
     return message;
   }
@@ skipping 12 matching lines @@
   static String convertToString(value) {
     if (value is ErrorToken) {
       // Shouldn't happen.
       return value.assertionMessage;
     } else if (value is Token) {
       value = value.lexeme;
     }
     return '$value';
   }
 }