Scoped kind variables do not work with default associated types
I have
{-# LANGUAGE PolyKinds, TypeFamilies, ScopedTypeVariables #-}
module Bug where
class C (a :: k) where
type F (a :: k)
type F (a :: k) = IntCompiling gives me
Bug.hs:7:11:
The signature specified kind ‘k1’, but ‘a’ has kind ‘k2’
In the type ‘(a :: k)’
In the type instance declaration for ‘F’
In the class declaration for ‘C’The error is on the line declaring the default associated type for F. This happens in both 7.8.2 and HEAD. Having !ScopedTypeVariables causes no change, but I put it in the example to emphasize that adding !ScopedTypeVariables is not the solution.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.8.2 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |