illFormedType :: ErrorExtractor v loc (C.Context v loc)
illFormedType = cause >>= \case
  C.IllFormedType c -> pure c
  _                 -> mzero
illFormedType :: ErrorExtractor v loc (C.Context v loc)
illFormedType = cause >>= \case
  C.IllFormedType c -> pure c
  _                 -> mzero
illFormedType = cause >>= \case
  C.IllFormedType c -> pure c
  _                 -> mzero