You can disable the monomorphism restriction in your .ghci so it needn't trouble your interactive sessions further. My .ghci follows my signature. -- _jsn :set -XOverlappingInstances :set -XNoMonomorphismRestriction :set -XUnicodeSyntax :set -XArrows :set -Wall :set -fno-warn-name-shadowing :set -fwarn-unused-imports :set -fglasgow-exts :set +t