binary compatibility post 1.0

[kailuowang]

If we lock binary compatibility post 1.0, I think the main implication is that we can't add methods existing traits, however we can still add new traits.
If someone want to add a new extension to Option, he just need to create a new trait say OptionSyntax2 and let the
mouse.all extends and mouse.option extend this new trait.
Here is an example of this solution I am trying to suggest in a cats PR
typelevel/cats#2138 (comment)
In the case of implicit extension namespace collusion, I don't know a good solution, I imagine when user encounter this they just need to stop using the all-inclusive import and use specific imports to avoid the ones that causing conflicts.

[benhutchison]

IIUC that sort of binary compatibility break (methods added to trait) affects implementers of the trait only. Mouse doesn’t publish any traits designed to be extended by users, in contrast to cats.

So I think binary compatibility isn’t likely to be as problematic. My preference is to defer any promises until there’s feedback from users that they’re having problems.

[kailuowang]

That's a good point. I am +1 on deferring.