ghc panic with TypeError
When playing around with TypeError
I got a ghc panic with the following code:
{-# LANGUAGE DataKinds, FlexibleContexts, TypeOperators,
FlexibleInstances, UndecidableInstances #-}
import GHC.TypeLits
class C t where
instance
(TypeError (Text "A" :<>: {- Text -} "B"))
=> C t where
main :: IO ()
main = return ()
Compiling this results in
ghc: panic! (the 'impossible' happened)
(GHC version 8.0.0.20160204 for x86_64-unknown-linux):
fvProv falls into a hole {a1bh}
Commenting "in" the second Text
removes the panic.
Trac metadata
Trac field | Value |
---|---|
Version | 7.10.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |