[ghc-steering-committee] Fwd: Please review #640: Fix quantification order for a `op` b and a %m -> b (Recommendation: Accept)

[Malte Ott]

Okay, let me summarize the voiced opinions:

We have agreement on the change to multiplicities.

On the infix type operator we are a bit stuck:

* Richard, Eric and I are in favor of fixing the bug.
* Adam and Arnaud are in favor of staying stable, living with the exception
* Simon was on the fix side but switched to undecided, waiting for more opinions
* Moritz preferred staying stable, but deferred to Simon before his switch

Overall slightly more votes for the change but subjectively hold less strongly
than the opinions against it.

Since I am unclear on how to proceed I’d love to hear more opinions (especially
of committee members who haven’t voiced theirs about this proposal).

I am generally not a fan of enshrining historic coincidence in the language when
the cost of fixing it is bareable. On the other hand this is such a minor detail
that I don’t think it will matter much in either direction.

If we cannot come to a consensus soon I will put it a to a vote. We
shouldn’t spend too much time on this.

Best
Malte

On 2024-03-19 15:12, Arnaud Spiwack wrote:
> On Tue, 19 Mar 2024 at 10:26, Simon Peyton Jones <
> simon.peytonjones at gmail.com> wrote:
> 
> > But I think you are now saying that *even if a left-to-right order was
> > "best", *there is a long-standing bug in GHC that puts `b` first in (a
> > `b` c`), and it's not worth the risk of change.   So instead we should
> > institutionalise the bug into the spec.
> >
> 
> This is, at least, my position. This is a bug fix, but the bug is so tiny,
> that even if the breakage is rare, it's not necessarily worth it, and it
> may be better to bake the exception into the spec. I'm weakly on the side
> that baking the exception is better.

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