SE-0365: Allow implicit self for weak self captures, after self is unwrapped

[DevAndArtist (Adrian Meister)]

If this proposal would block self-rebinding for instances other than a captured self reference, then I would be very much against it (-1). Not needing to write self in some places is great, but it shouldn‘t be limited to only the captured outer self. This way, it would be a wasted opportunity.

Related discussion:

@Joe_Groff

We could steal an idea from Kotlin and let you bind self in the scope of a closure:

let dateFormatter = with(DateFormatter()) { self in
    dateStyle = .short
    timeStyle = .long
}

which seems like a reasonable extension of the much-demanded guard let self = self rebinding idea.