Swift Tuple Wat

wat.swift

struct S<Args, Return> {}

infix operator ~
func ~ <A, T>(lhs: (A) -> T, rhs: String) -> S<(A), T> {
	return S()
}
func ~ <A, B, T>(lhs: (A, B) -> T, rhs: String) -> S<(A, B), T> {
	return S()
}

func f(_: Int, _: Int) -> Int { return 0 }

// Swift can't tell which `~` to use. That makes some sense.
_ = f ~ ""

// But this is also ambiguous:
let _: S<(Int, Int), Int> = f ~ ""

// However, more than one set of parens will disambiguate:
let _: S<((((Int, Int)))), Int> = f ~ ""