How to describe this bug?

Sönke Hahn shahn at
Fri Jul 13 12:18:11 CEST 2012

On 07/13/2012 03:12 AM, Bardur Arantsson wrote:
> Speaking of which... would it be remiss of me to mention the elephant in
> the room, namely the Eq instance for Float?
> AFAICT there is no possible way for a Float value to fulfill the Eq type
> class requirements, so why is it an instance? (I'm thinking of the
> "weird" Nan/Infinity behvaior primarily). Is there *really* such a huge
> amount of code out there that relies on an Eq (or Ord for that matter!)
> instance for Float? If so... shouldn't that code be fixed rather than
> being subtly buggy?

Num inherits from Eq, so Float couldn't have an instance for Num if we
didn't have that Eq instance.

BTW: My newsgroup client seems to have eaten my last mail. I filed a bug
report here:


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