Implement generalized function types.

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

Index: pkg/front_end/lib/src/fasta/errors.dart
diff --git a/pkg/front_end/lib/src/fasta/errors.dart b/pkg/front_end/lib/src/fasta/errors.dart
index f80c09d0e5839d3f1f9bbf30842c83cd7ebda49b..98493c4db5d06d7e8356d6e7c71f9b973cbe13a5 100644
--- a/pkg/front_end/lib/src/fasta/errors.dart
+++ b/pkg/front_end/lib/src/fasta/errors.dart
@@ -51,6 +51,9 @@ dynamic internalError(Object error, [Uri uri, int charOffset = -1]) {
 /// handled correctly, the user will never see a stack trace that says "user
 /// error".
 dynamic inputError(Uri uri, int charOffset, Object error) {
+  if (errorsAreFatal && isVerbose) {
+    print(StackTrace.current);
+  }
   throw new InputError(uri, charOffset, error);
 }