| Just (io_tycon, io_res_ty, co) <- tcSplitIOType_maybe result_ty
-- isIOType_maybe handles the case where the type is a
-- simple wrapping of IO. E.g.
| Just (io_tycon, io_res_ty, co) <- tcSplitIOType_maybe result_ty
-- isIOType_maybe handles the case where the type is a
-- simple wrapping of IO. E.g.