21 May
2021
21 May
'21
2:11 a.m.
encouraging the use of a standalone signature for type declarations where at least one parameter of the datatype does not have kind Type.
So Dict, Eq both get a sig but Fix and Either do not? type Dict :: Constraint -> Type type Eq :: Type -> Constraint type Fix :: (Type -> Type) -> Type It's sensible to exclude tired tropes like `Type` and `Type -> Type` but higher-order functors (like Fix) warrant a signature. Caveat: The kind of type synonyms, type families and data families is not necessarily determined by counting the syntactic arguments of X like for a `data' declaration as Y could be a type, a functor, a bifunctor.. type X = Y