standalone deriving for typeable fails
import Data.Typeable
data D a = C1 a | C2 (D a)
deriving instance Typeable a => Typeable (D a)
-- deriving Typeable
x = show $ typeOf (undefined::D Int)
main = print x
yields:
[1 of 1] Compiling Main ( T.hs, T.o )
ghc-6.8.1: panic! (the 'impossible' happened)
(GHC version 6.8.1 for i386-unknown-linux):
No match in record selector Var.tcTyVarDetails
Trac metadata
Trac field | Value |
---|---|
Version | 6.8.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | Unknown |
Architecture | Unknown |