I've left comments on the Github thread.

I'm rather sympathetic to this idea. I personally think that the implicit binding rules that we have in place are a bit messy, so simply turning them off may be of help.

My Github comments raise two points:

- The proposal is a tad challenging to read, and I'd like some improvements before acceptance be considered

- I'm questioning whether we really want two extensions for these two very related behaviours

On Mon, Nov 11, 2019 at 10:44 AM Simon Marlow <marlowsd@gmail.com> wrote:

Proposal #285:

https://github.com/ghc-proposals/ghc-proposals/pull/285

suggests two new LANGUAGE pragmas -XNoImplicitForall and -XNoPatternSignatureBinds.

They have the effect of making a subset of existing programs illegal, and in that sense I don't think these are problematic. The intention is that these would be used with ExplicitForalls to enforce that all identifiers have explicit binding sites. I'm generally supportive of that.

However I think we should be wary of the potential future direction, mentioned in the proposal:

> As described in the motivation, this opens the door to other means to bind the previously implicitly bound variables.

i.e. an unbound name in a type could refer to a type variable bound in an enclosing scope. This would be a language *change*, not merely an addition or subtraction, and hence potentially fork-like. So we would want to consider very carefully whether that's the direction we want to take the language.

But since that isn't part of the current proposal, and the current proposal is merely an optional subtraction, I don't think it's controversial.

Cheers

Simon

On Thu, 7 Nov 2019 at 09:29, Joachim Breitner <mail@joachim-breitner.de> wrote:

Dear Committee,

this is your secretary speaking:

-XNoImplicitForAll
has been proposed by John Ericson
https://github.com/ghc-proposals/ghc-proposals/pull/285
https://github.com/Ericson2314/ghc-proposals/blob/no-implicit-forall/proposals/0000-no-implicit-forall.rst

I propose Simon Marlow as the shepherd.

Please reach consensus as described in
https://github.com/ghc-proposals/ghc-proposals#committee-process
I suggest you make a recommendation, in a new e-mail thread with the
proposal number in the subject, about the decision, maybe point out
debatable points, and assume that anyone who stays quiet agrees with
you.

Thanks,
Joachim
--
Joachim Breitner
  mail@joachim-breitner.de
  http://www.joachim-breitner.de/

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