swift-mirror/test/Generics/unavailable_conformances.swift

// RUN: %target-typecheck-verify-swift

protocol P { }

struct X { }

@available(*, unavailable)
extension X: P { }

struct Y<T: P> { }

@available(*, unavailable)
extension Y {
  // Okay, because the unavailable conformance is used within an
  // unavailable context.
  init() where T == X { }
}

// A more elaborate setup that hits the conformance check in property map
// construction rather than concrete contraction.

protocol AssocP {}

@available(*, unavailable)
struct ConcreteP {}

@available(*, unavailable)
extension ConcreteP: AssocP {}

protocol Base {
  associatedtype T : AssocP
}

@available(*, unavailable)
extension Base where T == ConcreteP {}

// Hashable conformance synthesis ran into problems if the conformance was
// unavailable (which is legal if the type is unavailable also).
@available(*, unavailable)
struct Foo {
  class Bar {}
}

@available(*, unavailable)
extension Foo.Bar: Equatable {
    static func == (lhs: Foo.Bar, rhs: Foo.Bar) -> Bool { return false }
}

@available(*, unavailable)
extension Foo.Bar: Hashable {
    func hash(into hasher: inout Hasher) {}
}