Outdated comment (or bug?) in `types/TyCon.hs`
The docstring for
coreExpandTyCon_maybe says it should do something different than
tcExpandTyCon_maybe, but it doesn't:
-- ^ Used to create the view the /typechecker/ has on 'TyCon's. -- We expand (closed) synonyms only, cf. 'coreExpandTyCon_maybe' tcExpandTyCon_maybe = ... -- ^ Used to create the view /Core/ has on 'TyCon's. We expand -- not only closed synonyms like 'tcExpandTyCon_maybe', -- but also non-recursive @newtype@s coreExpandTyCon_maybe tycon tys = tcExpandTyCon_maybe tycon tys
If the code is correct, and the comment is just outdated, than Note [Newtype eta] and the docstrings for
Type.tcView should be updated as well.
The last big change to
coreExpandTyCon_maybe was made in commit fdf86568.