Need kind annotations
In his blog post Edward Kmett finds that he needs kind annotations. In particular, he wants to be able to say this:
class Category (c :: k -> k -> *) where
type Ob c :: k -> Constraint
id :: Ob c a => c a a
(.) :: (Ob c a, Ob c b, Ob c c) => c b c -> c a b -> c a c
Note that the kind of Ob
must match the kind of c
, so to declare its kind you need to mention the kind variable k
, and that means k
must be in scope.
Trac metadata
Trac field | Value |
---|---|
Version | 7.4.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |