I don't know what you mean. fmap for an uninhabited type is vacuously strict: its result is always _|_.
On Sun, Jan 15, 2017 at 11:00 PM, Kevin Cotrone <kevincotr...@gmail.com> wrote: > That seems to have a surprising strictness. > > I'm not sure if it would be the best idea to try and evaluate a type with no > inhabitants. > > On Sun, Jan 15, 2017 at 2:37 PM, David Feuer <david.fe...@gmail.com> wrote: >> >> Currently, if you write >> >> data V a deriving Functor >> >> GHC generates >> >> fmap _ _ = error "Void fmap" >> >> This seems quite unfortunate, because it loses potentially useful error >> information: >> >> fmap (+ 3) (error "Too many snozzcumbers!") >> >> throws "Void fmap", rather than the much more precise "Too many >> snozzcumbers!" I've opened Trac #13117 to fix this, but I figured I should >> double check that no one is opposed. >> >> David Feuer >> >> _______________________________________________ >> Libraries mailing list >> librar...@haskell.org >> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries >> > _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users