methods and associated types treated differently wrt. qualification
Say I have the following module:
{-# LANGUAGE TypeFamilies #-}
module M where
class C a where
type T a :: *
m :: a
Now I use this module in another module via a qualified import:
{-# LANGUAGE TypeFamilies #-}
module U where
import qualified M
instance M.C Integer where
type M.T Integer = Integer
m = 0
Note that in the instance declaration, the associated type T
is qualified, while the method m
is not. Removing the qualification of T
is not accepted by GHC, but neither is adding a qualification to m
. I think this inconsistency is unfortunate, so that it might be good to remove it.
Trac metadata
Trac field | Value |
---|---|
Version | 7.0.4 |
Type | FeatureRequest |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |