"Preserving user bottoms" was found to be better behavior for us with Void
as well back in the day. Evaluating such a term to get the bottom out is
better than making up one that loses information for the user about
precisely what bottom it is they had. We do so with absurd and the like for
Void.
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 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
> inhabitan
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
snozzcu
