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

// Inheritable: method with 'Self' in contravariant position.
protocol P1 {
  func f1a(_ x: Self?) -> Bool

  func f1b(_ x: [Self])

  func f1c(_ x: [String : Self])
}

// Inheritable: property with 'Self' in its signature.
protocol P2 {
  var prop2: Self { get set }
}
protocol P2a {
  var prop2a: Self { get set }
}

// Inheritable: subscript with 'Self' in its result type.
protocol P3 {
  subscript (i: Int) -> Self { get }
}

// Inheritable: subscript with 'Self' in its index type.
protocol P4 {
  subscript (s: Self) -> Int { get }
}

// Potentially inheritable: method returning Self
protocol P5 {
  func f5() -> Self
}
protocol P5a {
  func f5a() -> Self
}

// Inheritable: method returning Self
protocol P6 {
  func f6() -> Self
}

// Inheritable: method involving associated type.
protocol P7 {
  associatedtype Assoc
  func f7() -> Assoc
}

// Inheritable: initializer requirement.
protocol P8 {
  init(int: Int)
}

// Inheritable: operator requirement.
protocol P9 {
  static func ==(x: Self, y: Self) -> Bool 
}

// Never inheritable: method with 'Self' in invariant position.
struct G<T> {}
protocol P10 {
  func f10(_ arr: G<Self>)
}
protocol P10a {
  func f10a(_ arr: G<Self>)
}

// Never inheritable: method with 'Self' in curried position.
protocol P11 {
  func f11() -> (_ x: Self) -> Int
}

// Inheritable: parameter is a function returning 'Self'.
protocol P12 {
  func f12(_ s: () -> (Self, Self))
}

// Never inheritable: parameter is a function accepting 'Self'.
protocol P13 {
  func f13(_ s: (Self) -> ())
}

// Inheritable: parameter is a function accepting a function
// accepting 'Self'.
protocol P14 {
  func f14(_ s: ((Self) -> ()) -> ())
}

// Never inheritable: parameter is a function accepting a function
// returning 'Self'.
// Not Inheritable: method returning tuple containing 'Self'.
// Not Inheritable: method returning array of 'Self'.
// Not Inheritable: requirement with reference to covariant 'Self', if this
// reference is not the uncurried type, stripped of any optionality.
protocol P15 {
  func f15(_ s: (() -> Self) -> ())
  func f16() -> (Self, Self)
  func f17() -> Array<Self>
  func f18() -> (Never, Array<Self>)
}
extension P15 {
  func f18() -> (Never, Array<Self>) {} // expected-note {{'f18()' declared here}}
}

// Class A conforms to everything that can be conformed to by a
// non-final class.
class A : P1, P2, P3, P4, P5, P6, P7, P8, P9, P10 {
  // P1
  func f1a(_ x: A?) -> Bool { return true }

  func f1b(_ x: [A]) { }

  func f1c(_ x: [String : A]) { }

  // P2
  var prop2: A { // expected-error{{property 'prop2' in non-final class 'A' must specify type 'Self' to conform to protocol 'P2'}}
    get { return self }
    set {}
  }

  // P2a
  var prop2a: A { // expected-note {{'prop2a' declared here}}
    get { return self }
    set {}
  }

  // P3
  subscript (i: Int) -> A { // expected-error{{subscript 'subscript(_:)' in non-final class 'A' must return 'Self' to conform to protocol 'P3'}}
    get {
     return self
    }
  }

  // P4
  subscript (a: A) -> Int { 
    get {
      return 5
    }
  }

  // P5
  func f5() -> A { return self } // expected-error{{method 'f5()' in non-final class 'A' must return 'Self' to conform to protocol 'P5'}}

  // P5a
  func f5a() -> A { return self } // expected-note {{'f5a()' declared here}}

  // P6
  func f6() -> Self { return self }

  // P7
  func f7() -> Int { return 5 }

  // P8
  required init(int: Int) { }

  // P10
  func f10(_ arr: G<A>) { } // expected-error{{protocol 'P10' requirement 'f10' cannot be satisfied by a non-final class ('A') because it uses 'Self' in a non-parameter, non-result type position}}

  // P10a
  func f10a(_ arr: G<A>) { } // expected-note {{'f10a' declared here}}

  // P11
  func f11() -> (_ x: A) -> Int { return { x in 5 } }
}

extension A: P2a, P5a, P10a {}
// expected-error@-1 {{property 'prop2a' in non-final class 'A' must specify type 'Self' to conform to protocol 'P2a'}}
// expected-error@-2 {{method 'f5a()' in non-final class 'A' must return 'Self' to conform to protocol 'P5a'}}
// expected-error@-3 {{protocol 'P10a' requirement 'f10a' cannot be satisfied by a non-final class ('A') because it uses 'Self' in a non-parameter, non-result type position}}

// P9
func ==(x: A, y: A) -> Bool { return true }

// Class B inherits A; gets all of its conformances.
class B : A { 
  required init(int: Int) { }
}

func testB(_ b: B) {
  var _: any P1 = b
  var _: any P4 = b
  var _: any P5 = b
  var _: any P6 = b
  var _: any P7 = b
  var _: any P8 = b
  var _: any P9 = b
}

// Class A5 conforms to P5 in an inheritable manner.
class A5 : P5 {
  // P5 
  func f5() -> Self { return self }
}

// Class B5 inherits A5; gets all of its conformances.
class B5 : A5 { }

func testB5(_ b5: B5) {
  var _: P5 = b5 // okay
}

// Class A8 conforms to P8 in an inheritable manner.
class A8 : P8 {
  required init(int: Int) { }
}

class B8 : A8 {
  required init(int: Int) { }
}

func testB8(_ b8: B8) {
  var _: P8 = b8 // okay
}

// Class A9 conforms to everything.
final class A9 : P1, P2, P3, P4, P5, P6, P7, P8, P9, P10 {
  // P1
  func f1a(_ x: A9?) -> Bool { return true }

  func f1b(_ x: [A9]) { }

  func f1c(_ x: [String : A9]) { }

  // P2
  var prop2: A9 {
    get { return self }
    set {}
  }

  // P3
  subscript (i: Int) -> A9 {
    get {
     return self
    }
  }

  // P4
  subscript (a: A9) -> Int { 
    get {
      return 5
    }
  }

  // P5
  func f5() -> A9 { return self }

  // P6
  func f6() -> Self { return self }

  // P7
  func f7() -> Int { return 5 }

  // P8
  required init(int: Int) { }

  // P10
  func f10(_ arr: G<A9>) { }

  // P11
  func f11() -> (_ x: A9) -> Int { return { x in 5 } }
}

// P9
func ==(x: A9, y: A9) -> Bool { return true }

class A12 : P12 {
  func f12(_ s: () -> (A12, A12)) {}
}

class A13 : P13 {
  func f13(_ s: (A13) -> ()) {} // expected-error{{protocol 'P13' requirement 'f13' cannot be satisfied by a non-final class ('A13') because it uses 'Self' in a non-parameter, non-result type position}}
}

class A14 : P14 {
  func f14(_ s: ((A14) -> ()) -> ()) {}
}

class A15 : P15 { // expected-error{{protocol 'P15' requirement 'f18()' cannot be satisfied by a non-final class ('A15') because it uses 'Self' in a non-parameter, non-result type position}}
  func f15(_ s: (() -> A15) -> ()) {} // expected-error{{protocol 'P15' requirement 'f15' cannot be satisfied by a non-final class ('A15') because it uses 'Self' in a non-parameter, non-result type position}}
  func f16() -> (A15, A15) {} // expected-error{{protocol 'P15' requirement 'f16()' cannot be satisfied by a non-final class ('A15') because it uses 'Self' in a non-parameter, non-result type position}}
  func f17() -> Array<A15> {} // expected-error{{protocol 'P15' requirement 'f17()' cannot be satisfied by a non-final class ('A15') because it uses 'Self' in a non-parameter, non-result type position}}
}