ConstraintKinds and reifyInstances
reifyInstances doesn't appear to know how to deal with a constraint that is just an alias. For example, the following prints (True,False):
{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE TemplateHaskell #-}
import Language.Haskell.TH
import Language.Haskell.TH.Syntax
class C a
instance C Int
type D a = C a
main = print $(
do isCInst <- isInstance ''C [ConT ''Int]
isDInst <- isInstance ''D [ConT ''Int]
lift (isCInst,isDInst))
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.6.3 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |