The values for each value of the `BoxFit` enum all say they are `const BoxFit(null)`

[Hixie]

The values for each value of the BoxFit enum all say they are const BoxFit(null):

https://docs.flutter.io/flutter/painting/BoxFit-class.html

[jcollins-g]

This doesn't seem to be widespread, but no immediate idea what's gone wrong here.

[jcollins-g]

Code references trigger construction of enum members in a way the class doesn't expect, creating this bug.

[jcollins-g]

Also broken:
https://docs.flutter.io/flutter/rendering/AxisDirection-class.html
https://docs.flutter.io/flutter/widgets/BannerLocation-class.html
https://docs.flutter.io/flutter/painting/BorderStyle-class.html
https://docs.flutter.io/flutter/dart-ui/BlurStyle-class.html
https://docs.flutter.io/flutter/widgets/CrossFadeState-class.html
...
and apparently, quite a few more. This may be getting worse than when it was initially reported as more code references are added.