On Fri, Jan 20 2012 at 06:22 +0100, Evan Laforge wrote: > On Thu, Jan 19, 2012 at 8:53 PM, Edward Z. Yang <[email protected]> wrote: >> It's not obvious that this should be turned on by -Wall, since >> you would also trigger errors on uses like: >> >> [ x | Just x <- xs ]
> [...] > I would have suggested that listcomp > match failures yield [] but monad ones be errors, but now that list > comps and monads are back together again maybe that's not so easy to > do... > Perhaps a generalization of this would be to warn only if fail was inherited by the original Monad typeclass, where it seems obvious that fail takes the role of a ``work-around''. When fail is overwritten one could perhaps assume that calling it is the intended behavior for pattern match failures. Lu _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
