Index: b/cereal.cabal
===================================================================
--- a/cereal.cabal
+++ b/cereal.cabal
@@ -39,9 +39,6 @@ library
         build-depends:          base >= 4.4 && < 5, containers, array,
                                 ghc-prim >= 0.2
 
-        if !impl(ghc >= 8.0)
-          build-depends:        fail == 4.9.*
-
         if flag(bytestring-builder)
           build-depends:        bytestring >= 0.9    && < 0.10.4,
                                 bytestring-builder >= 0.10.4 && < 1
