// RUN: %target-swift-emit-silgen %s | %FileCheck %s

struct Foo<T> {
}

protocol Runcible {
  associatedtype Spoon
  associatedtype Hat
}

extension Foo {
  // An unconstrained extension in the same module doesn't use the extension
  // mangling, since the implementation can be resiliently moved into the
  // definition.
  // CHECK-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooV1aSivg
  // NO-SELF-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooV1aSivg
  var a: Int { return 0 }

  // NO-SELF-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooV3zimyyF
  func zim() { }
  // NO-SELF-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooV4zangyyqd__lF
  func zang<U>(_: U) { }
  // NO-SELF-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooV4zungyyqd__AA8RuncibleRd__3HatQyd__Rs_lF
  func zung<U: Runcible>(_: U) where U.Hat == T { }
}

extension Foo where T: Runcible {
  // A constrained extension always uses the extension mangling.
  // CHECK-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooVA2A8RuncibleRzlE1aSivg
  var a: Int { return 0 }

  // CHECK-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooVA2A8RuncibleRzlE1bxvg
  var b: T { get { } }
}

extension Foo where T: Runcible, T.Spoon: Runcible {
  // CHECK-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooVA2A8RuncibleRzAaD5SpoonRpzlE1aSivg
  var a: Int { return 0 }

  // CHECK-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions3FooVA2A8RuncibleRzAaD5SpoonRpzlE1bxvg
  var b: T { get { } }
}

// Protocol extensions always use the extension mangling.
// TODO: When default implementations are properly implemented, and protocol
// extensions receive dynamic dispatch, it would be possible for an
// unconstrained protocol extension method to be moved in or out of its
// declaration, so we would no longer want to use the extension mangling
// in unconstrained cases.
extension Runcible {
  // CHECK-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions8RunciblePAAE5runceyyF
  func runce() {}
}

extension Runcible where Self.Spoon == Self.Hat {
  // CHECK-LABEL: sil hidden [ossa] @$s27mangling_generic_extensions8RunciblePAA5SpoonQz3HatRtzrlE5runceyyF
  func runce() {}
}


struct Bar<T: Runcible, U: Runcible> { }

extension Bar {
  // CHECK-LABEL: $s27mangling_generic_extensions3BarV4bar1yyqd__AA8RuncibleRd__AaE5SpoonRpzAFQy_AGRSlF
  func bar1<V: Runcible>(_: V) where U.Spoon: Runcible, T.Spoon == U.Spoon { }

  // CHECK-LABEL: $s27mangling_generic_extensions3BarV4bar1yyqd__AA8RuncibleRd__AaE5SpoonRp_lF
  func bar1<V: Runcible>(_: V) where U.Spoon: Runcible { }
}