ghc: panic! (the 'impossible' happened)
ghc: panic! (the 'impossible' happened)
(GHC version 8.0.2 for x86_64-unknown-linux):
initTc: unsolved constraints
WC {wc_insol =
[W] ask_an9K :: t_an9J[tau:1] (CHoleCan: ask)
[W] put_an9Q :: t_an9P[tau:1] (CHoleCan: put)}
So this code derives an instance of the Decimal type incorrectly, but not sure if this is causing the error.
I have some nested records, which contain a few Decimals. I am trying to make them acidic.
instance SafeCopy (DecimalRaw a) where
putCopy (Decimal d) = contain $ safePut d
getCopy = contain $ Decimal <$> safeGet
deriveSafeCopy 0 'base ''Client
deriveSafeCopy 0 'base ''Article
deriveSafeCopy 0 'base ''ServerData
makeLenses ''ServerData
writeState :: String -> Update ServerData ()
writeState newValue
= put (ServerData newValue)
queryState :: Update ServerData String
queryState = do ServerData string <- ask
return string
makeAcidic ''ServerData ['writeState 'queryState]
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |