Fix compile error for ghc-7.10.2
Fix compile error for ghc-7.10.2

gibiansky/IHaskell,franklx/IHaskell,sumitsahrawat/IHaskell,artuuge/IHaskell,qzchenwl/IHaskell,FranklinChen/IHaskell,artuuge/IHaskell,thomasjm/IHaskell,kfiz/IHaskell,FranklinChen/IHaskell,qzchenwl/IHaskell,FranklinChen/IHaskell,franklx/IHaskell,sumitsahrawat/IHaskell,gibiansky/IHaskell,artuuge/IHaskell,wyager/IHaskell,wyager/IHaskell,kfiz/IHaskell,gibiansky/IHaskell,thomasjm/IHaskell,qzchenwl/IHaskell,artuuge/IHaskell,FranklinChen/IHaskell,thomasjm/IHaskell,franklx/IHaskell,wyager/IHaskell,franklx/IHaskell,kfiz/IHaskell,sumitsahrawat/IHaskell,beni55/IHaskell,wyager/IHaskell,beni55/IHaskell,beni55/IHaskell,thomasjm/IHaskell,kfiz/IHaskell,qzchenwl/IHaskell,beni55/IHaskell