On Mon, 9 Oct 2023 at 15:22, Joachim Breitner <mail@joachim-breitner.de> wrote:

That is my understanding, yes.  Oleg, who suggested this originally (I
just wrote it up) says (see motivation section of the proposal)

> not having -Wsevere=missing-methods by default essentially prevents 
> any (true) breakage assessment of adding new, non-defaulted members
> to existing type-classes.

If the goal is to do a breakage assessment, couldn't you make the change to your library and then build all of Hackage with `--ghc-option=-Werror=severe`?

Cheers
Simon
 


> Wouldn't this be something that PVP should guard against? Adding new
> fields should result in a new major version, because
> it's technically a breaking change?

Yeah, probably in a world where everyone follows the PVP perfectly, we
wouldn’t have this discussion.

Am Montag, dem 09.10.2023 um 14:38 +0100 schrieb Chris Dornan:
> If I understand you rightly, you are arguing that any legacy packages
> that would flag severe warnings should now fail to compile, even if 
> they are marked as being (say) Haskell2010?

I’m not arguing that we should do this, but I am arguing that this is
the question we are supposed to decide here. (I’m personally not
decided

> If the impetus for the proposal was driven by observed problematic
> failures of packaged code that could be caught by these warnings
> then, for me, there would be a discussion to be had.

My understanding, based on the motivation section, is that this _is_
the impetus.

Cheers,
Joachim


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

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