Block implementations do not have associated block types

[haykam821]

[Patbox]

While technically this is a bug, currently that feature is unused outside of datagen exports, and even then many mods don't work with it (including mine). This is something that will make most sense to fix when vanilla ends up using these outside of that, likely once the blocks become data driven (but also then it might make sense to fully rethink how the Polymer's replacement system works)