Report messages instead of just printing.

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

Index: pkg/front_end/lib/src/fasta/problems.dart
diff --git a/pkg/front_end/lib/src/fasta/problems.dart b/pkg/front_end/lib/src/fasta/problems.dart
index 26b34233ece93de135e939555334b525553d8d5d..a9105f54fd8234c802cc13c0653ff7486f3a7375 100644
--- a/pkg/front_end/lib/src/fasta/problems.dart
+++ b/pkg/front_end/lib/src/fasta/problems.dart
@@ -4,15 +4,18 @@
 
 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
@@ -23,15 +26,8 @@ import 'messages.dart'
 ///
 /// 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]) {