[forwarding this manually as the BTS doesn't send to a mailing list; the bug is at http://hackage.haskell.org/trac/hackage/ticket/100 ] I'm not sure if this should be a bug(enhancement) report or on the mailing list, but I've gone with putting it here so that it won't be accidentally forgotten about. Allowing both Setup.hs and Setup.lhs causes minor annoyances all over the place when working with cabal packages, and moreso when writing tools to work with cabal packages. There are also a couple of larger problems I've had. For example, when writing a Makefile that builds all cabal packages in subdirectories (i.e. (re)make setup if necessary, configure and build) it is hard (for me at least!) to tell make "setup depends on whichever of Setup.hs and Setup.lhs exists". The benefits of allowing Setup.hs are small. For the common case you only save a couple of copies of > , while for larger Setup.lhs files \begin{code} and \end{code} at the start and end is not significant overhead. The reason for choosing to keep Setup.lhs over Setup.hs is so that we can use #! scripts etc without having to worry about the Haskell impl trying to parse it. Thus I would like to propose dropping support for Setup.hs and supporting Setup.lhs only. It would probably be necessary for cabal to complain if it finds a Setup.hs file, as otherwise people wouldn't notice they hadn't updated their packages. Thanks Ian