Currently this functions has the type

SocketPrim.Socket -> PrelHandle.IOMode -> IO PrelIOBase.Handle

Could you change the order of the arguments, please? I can`t see any particular requirement of the socket being the first argument, but swapping it with IOMode would eliminate an additional 'flip' when mapping socketToHandle over a list of sockets, e.g.:

handles <- mapM (socketToHandle ReadMode) sockets -- Volker Stolz * vs@foldr.org * PGP + S/MIME