15 Jan
2017
15 Jan
'17
11 p.m.
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
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 Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries