Remove eq and show from num class

[Bardur Arantsson]

On 2017-09-08 13:55, Anthony Clayden wrote:

>> This has been how it is in GHC for a long time now,
>> so it really is a matter for the Haskell' committee
>> rather than one of the GHC committees.
> 
> MPTCs, GADTs (for example) have been in GHC
> far longer.

AFAIUI these are far from trivial to spec without reference to
implementation details such as the type inference algorithm, etc.

> 
> OK it's bit naughty GHC doesn't have a flag
> for something that's not compliant to the report.
> But that's a GHC issue, not a grounds for changing
> the language spec.
> 

It's a strong hint that the spec should be changed. There aren't really
any widely used Haskell compilers other than GHC and speccing for things
that aren't actually used in practice is a waste of time (at best) and
actively harmful (at worst). There's a reason that Design by Committee
is generally seen as a bad thing if you don't actually have an
implementation to guide the spec.

Regards,