@opensdh: could you kindly review this?

The discussion on the issue mostly focused on the "enclosing" phrasing. Isn't the using-directive necessary for unqualified lookup? [namespace.qual]/1 says that qualified lookup "additionally searches every element of the inline namespace set", but unqualified lookup has only the directives ([basic.lookup.unqual]/2.2).

@jensmaurer: any thoughts?

@opensdh, you're right. I'll reduce this pull request to just talk about "innermost enclosing" then, and leave the using-directive alone.

Do you feel we could/should add an explicit bullet to basic.lookup.unqual that talks about looking in the inline namespace set? That feels a lot more straightforward than introducing a hypothetical using-directive.

@tkoeppe, this should be pretty straightforward now.

Thanks, that's indeed straight-forward. @opensdh: what do you think about following up as Jens suggests?

Since using-directives are transitive, you would have to add not a bullet to [basic.lookup.unqual]/2 but a rule after those bullets that for every namespace's scope explicitly searched in them, a search is also performed in every member of its inline namespace set. I don't know whether that's nicer than the current formulation.

@opensdh: Thanks! I find it hard to tell. @jensmaurer, feel free to propose something if you think the exposition could be made easier to follow here, and we can see if it's worth it. But it sounds like the status quo isn't all that bad, either.