I have a project that was building fine a few days ago, since then I haven't changed my dart-sdk or any library dependencies or update dart editor to my knowledge, I just made a very small change to one of my polymer elements to use paper-buttons instead of standard buttons, the change can be seen here Now when I run pub build I get the following errors, and I have no idea why, if I look in packages polymer/polymer.dart does exist and dart editor doesn't show any warnings in the project. similarly if I undo my latest changes and go back to my last working version I still get this exact same error, so I'm not sure how to debug this, any hints would be much appreciated.
Can't read 'package:polymer/polymer.dart' (Could not find asset polymer|lib/polymer.dart.).
import 'package:polymer/polymer.dart';
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^