cabal: express condition positively

andreasabel · andreasabel · commit f967427f65ef · 2021-07-19T14:29:58.000+02:00
diff --git a/regex-posix.cabal b/regex-posix.cabal
@@ -94,7 +94,7 @@ library
                , bytestring >= 0.9 && < 0.12
                , array      >= 0.3 && < 0.6
 
-  if !impl(ghc >= 8)
+  if impl(ghc < 8)
       build-depends: fail == 4.9.*
 
   ghc-options: -O2
