How to describe this bug?

Aleksey Khudyakov alexey.skladnoy at
Fri Jul 13 17:41:59 CEST 2012

On 13.07.2012 19:27, Brandon Allbery wrote:
> On Fri, Jul 13, 2012 at 7:29 AM, Aleksey Khudyakov
> <alexey.skladnoy at <mailto:alexey.skladnoy at>> wrote:
>         Num inherits from Eq, so Float couldn't have an instance for Num
>         if we
>         didn't have that Eq instance.
>     No more since GHC 7.4. But Eq is indeed superclass of Ord and it Ord
>     is used a lot.
> ...but Float's Ord instance is even more dubious than its Eq.
What's wrong with it except for NaN? NaN surely breaks every law but 
otherwise it's OK.

More information about the Glasgow-haskell-users mailing list