diff --git a/pkgs/development/haskell-modules/configuration-ghc-6.12.x.nix b/pkgs/development/haskell-modules/configuration-ghc-6.12.x.nix index 33c7060f5f4..764064ae903 100644 --- a/pkgs/development/haskell-modules/configuration-ghc-6.12.x.nix +++ b/pkgs/development/haskell-modules/configuration-ghc-6.12.x.nix @@ -59,9 +59,7 @@ self: super: { ChasingBottoms = dontHaddock super.ChasingBottoms; # https://github.com/glguy/utf8-string/issues/9 - utf8-string = overrideCabal super.utf8-string (drv: { - patchPhase = "sed -ir -e 's|Extensions: | Extensions: UndecidableInstances, |' utf8-string.cabal"; - }); + utf8-string = appendConfigureFlag super.utf8-string "--ghc-option=-XUndecidableInstances"; # https://github.com/haskell/HTTP/issues/80 HTTP = doJailbreak super.HTTP;