8108ad9e0e
Extending visitor makes it impossible to get a static error when new syntax is added to Kernel. Also, add @override annotations so we can get a hint when syntax is removed from Kernel. Change-Id: I9f3111e406e9994e76a637d2782e24cde264fd31 Reviewed-on: https://dart-review.googlesource.com/46721 Commit-Queue: Kevin Millikin <kmillikin@google.com> Reviewed-by: Dmitry Stefantsov <dmitryas@google.com>