Make `eqTypeIO` that sees through type families
In my experience, the fact that
eqType only sees through type synonyms, but not type families, severely limits its usefulness.
It seems that it should be possible to implement
eqTypeIO that sees through type families, via
runTcInteractive, although I haven't studied the details.
The type would be something like
eqTypeIO :: HscEnv -> Type -> Type -> IO Bool (or a different monad, if
IO is not a good fit).
eqTypeIO, if possible.