Getting seg fault while trying to use appendSymbol

[mageshb]

Here is test code

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}
module Lib
    ( someFunc
    ) where

import Data.Constraint
import Data.Constraint.Symbol
import Data.Proxy
import GHC.TypeLits

someFunc :: IO ()
someFunc = do
  putStrLn $ ((symbolVal (Proxy :: Proxy ("Foo" ++ "Bar")))
              \\ (appendSymbol :: ((KnownSymbol "Foo", KnownSymbol "Bar") :- KnownSymbol ("Foo" ++ "Bar")))
             )

It core dumped in GHC 8.0.1 as well in 8.0.2
Is it a bug or am I missing something here

[RyanGlScott]

It is a bug, and it was fixed upstream in 55836e5. I'll try to get a new release on Hackage soon with this fix.

[mageshb]

Thank you @RyanGlScott

[RyanGlScott]

I've uploaded constraints-0.9.1 to Hackage with this fix.