Implement generalized function types.

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

 // Copyright (c) 2016, 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.errors;
 
 import 'dart:async' show Future;
 
 import 'dart:convert' show JSON;
 
@@ skipping 33 matching lines @@
 /// Used to report an error in input.
 ///
 /// Avoid using this for reporting compile-time errors, instead use
 /// `LibraryBuilder.addCompileTimeError` for those.
 ///
 /// An input error is any error that isn't an internal error. We use the term
 /// "input error" in favor of "user error". This way, if an input error isn't
 /// 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);
 }
 
 String printUnexpected(Uri uri, int charOffset, String message) {
   String formattedMessage = formatUnexpected(uri, charOffset, message);
   if (errorsAreFatal) {
     print(formattedMessage);
     if (isVerbose) print(StackTrace.current);
     throw new InputError(uri, charOffset, message);
   }
@@ skipping 107 matching lines @@
   return new Future.error(error, trace);
 }
 
 String safeToString(Object object) {
   try {
     return "$object";
   } catch (e) {
     return "Error when converting ${object.runtimeType} to string.";
   }
 }