diff --git a/pkgs/development/haskell-modules/configuration-ghc-7.10.x.nix b/pkgs/development/haskell-modules/configuration-ghc-7.10.x.nix
index 15a9d5a7f82..a453fac9dce 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-7.10.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-7.10.x.nix
@@ -108,6 +108,7 @@ self: super: {
   safecopy = dontCheck (super.safecopy);
 
   # test suite broken, some instance is declared twice.
+  # https://bitbucket.org/FlorianHartwig/attobencode/issue/1
   AttoBencode = dontCheck super.AttoBencode;
 
   # bos/attoparsec#92