On Wed, Nov 25, 2020 at 12:43 PM Joachim Breitner <mail@joachim-breitner.de> wrote:
Hi,

Thanks! I’ll update the tally later today.

Am Mittwoch, den 25.11.2020, 12:20 +0100 schrieb Spiwack, Arnaud:
> UnicodeSyntax: maybe
>     ^ I think it changes error messages. I don't think that we can
>     make error messages in Unicode by default. If it only affects
>     parsing, then I'm in favour.

That is my sentiment as well, and I would phrase my vote as:

  GHC2021 implies UnicodeSyntax, but not -fprint-unicode-syntax.
  Enabling UnicodeSyntax explicitly may still imply -fprint-unicode-syntax.

I guess the details of how GHC formats its messages are not strictly
our authority, so I didn't spell this out, but yes: it helps to paint
the picture here more clearly.

> InstanceSigs: no
>   -- ^ It does feel mostly innocuous on the surface, but it has a
>   probably surprising semantics. Considering that it's quite rarely
>   used, probably better left out.

Interesting, I don’t see a mention of this on
https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#extension-InstanceSigs
Can you elaborate?

I'm referring to:
> The type signature in the instance declaration must be more polymorphic than (or the same as) the one in the class declaration, instantiated with the instance type.

I may be overly conservative here, to be honest. But I'm just a tad hesitant. I should probably have written “a tad hesistant” instead of “no”, though. But this is a long list of extensions, and I was getting tired :) .

Also thanks for looking up which extensions are already in GHC,
Haskell2010 and are deprecated. I should indicate that in the table
somehow (or simply drop them from the ballot, at least the deprecated
ones).

 I don't claim exhaustiveness there. Nor am I 100% sure about correctness. For instance, I'm pretty sure that n+k patterns are considered deprecated, but the documentation doesn't reflect it. I still stored it in the deprecated section as there is basically no way that we turn this one on by default again.