Is there a way to convert between an existential type and the existential metatype of the same protocol, statically?

Using Swift
, ,
1

For example, is there any way to combine both of these associated types into one, and base the other off of it? I don't think so.

protocol P { }

protocol EP {
  associatedtype AnyP
  associatedtype AnyPType
}

enum E: EP {
  typealias AnyP = any P
  typealias AnyPType = any P.Type
}
2

Couldn't you say

func f(anyP: any P) {
  let anyPType = type(of: anyP)
}

?

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3

Of course. Thank you. I did a bad job simplifying my problem and have edited to ask what I actually needed to know, now.

4

That's right, there is no way to produce an any P.Type from a T.Type by substitution; you'll always get an (any P).Type. The type(of:) operation in the expression type checker does this as a special case, but the type of type(of:) cannot be expressed in the type system.

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