Gabriel439/Haskell-Pipes-Parse-Library — pull request #13 by k0001 (2013-08-02 01:27:48+00:00)
Title: Add missing LANGUAGE RankNTypes

This happened again.

I looked around, and it seems there was an issue in GHC that allowed higher-ranked types to be used without explicitly enabling them, [as explained in this comment in GHC issue #6302](http://ghc.haskell.org/trac/ghc/ticket/6032#comment:1). That could be why your GHC version isn't complaining.