Report messages instead of just printing.

pkg/front_end/lib/src/fasta/problems.dart

 // Copyright (c) 2017, 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 fasta.problems;
 
+import 'compiler_context.dart' show CompilerContext;
+
 import 'messages.dart'
     show
         Message,
-        deprecated_format,
         templateInternalProblemUnexpected,
         templateInternalProblemUnhandled,
         templateInternalProblemUnimplemented,
         templateInternalProblemUnsupported;
 
+import 'severity.dart' show Severity;
+
 /// Used to report an internal error.
 ///
 /// Internal errors should be avoided as best as possible, but are preferred
 /// over assertion failures. The message should start with an upper-case letter
 /// and contain a short description that may help a developer debug the issue.
 /// This method should be called instead of using `throw`, as this allows us to
 /// ensure that there are no throws anywhere else in the codebase.
 ///
 /// Before printing the message, the string `"Internal error: "` is prepended.
 dynamic internalProblem(Message message, int charOffset, Uri uri) {
-  String text = "Internal error: ${message.message}";
-  if (message.tip != null) {
-    text += "\n${message.tip}";
-  }
-  if (uri == null && charOffset == -1) {
-    throw text;
-  } else {
-    throw deprecated_format(uri, charOffset, text);
-  }
+  throw CompilerContext.current
+      .format(message.withLocation(uri, charOffset), Severity.internalProblem);
 }
 
 dynamic unimplemented(String what, [int charOffset = -1, Uri uri = null]) {
   return internalProblem(
       templateInternalProblemUnimplemented.withArguments(what),
       charOffset,
       uri);
 }
 
 dynamic unhandled(String what, String where, int charOffset, Uri uri) {
   return internalProblem(
       templateInternalProblemUnhandled.withArguments(what, where),
       charOffset,
       uri);
 }
 
 dynamic unexpected(String expected, String actual, int charOffset, Uri uri) {
   return internalProblem(
       templateInternalProblemUnexpected.withArguments(expected, actual),
       charOffset,
       uri);
 }
 
 dynamic unsupported(String operation, int charOffset, Uri uri) {
   return internalProblem(
       templateInternalProblemUnsupported.withArguments(operation),
       charOffset,
       uri);
 }