error: while evaluating the attribute 'nativeBuildInputs' of the derivation 'interactive-work-on-multi--combined-pkg-0-environment' at /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/pkgs/stdenv/generic/make-derivation.nix:177:11:
while evaluating the attribute 'paths' of the derivation 'ghc-8.0.2-with-packages' at /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/pkgs/stdenv/generic/make-derivation.nix:177:11:
while evaluating the attribute 'buildPhase' of the derivation 'hoogle-local-0.1' at /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/pkgs/stdenv/generic/make-derivation.nix:177:11:
while evaluating 'optionalString' at /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/lib/strings.nix:147:26, called from /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/pkgs/development/haskell-modules/hoogle.nix:65:7:
while evaluating 'concatMapStringsSep' at /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/lib/strings.nix:64:33, called from /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/pkgs/development/haskell-modules/hoogle.nix:68:10:
while evaluating anonymous function at /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/pkgs/development/haskell-modules/hoogle.nix:68:40, called from undefined position:
value is a list while a set was expected, at /nix/store/pxh6ar7qdnx3w5vhpqpf0d9jr1bxrsy1-source/pkgs/development/haskell-modules/hoogle.nix:68:43