The kind of (=>)
This is mainly a request for clarification, and not very important.
Is there any good (theoretical, implementation, practical, ...) reason why (with
ConstraintKinds) enabled, the
=> symbol on the type-level is still treated as a built-in syntactic construct rather than a type-level operator with
GHCi> :kind (=>) (=>) :: Constraint -> * -> *
Note that I'm not actually proposing to make it re-definable, but to treat it similarly to the
(->) type operator.