[Pitch] Introduce existential `any`

[Jumhyn (Frederick Kellison-Linn)]

@xwu

I’m of the understanding that the pitched meaning for (any P).Type is exactly what @Joe_Groff describes in the text you quote (“the type of the existential itself”). Indeed I cannot contemplate that spelling meaning anything else.

A different quote a bit further up better illustrates the difference:

@Joe_Groff

With the any modifier, there’s an opportunity to revise the current meta type syntax to be more obvious. P.Protocol , the type of P.self , would be (any P).Type , whereas the type of all T.self where T: P would be any P.Type if we say that P.Type is a generic constraint for a meta type conforming to P.

This proposal suggests that P.Type would become (any P).Type. Joe's previous suggestion was that P.Type becomes any (P.Type).