concurrent_value_checking.swift

// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -DALLOW_TYPECHECKER_ERRORS -verify-additional-prefix typechecker- -verify-additional-prefix tns-allow-typechecker-

// RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -strict-concurrency=complete -parse-as-library %s -emit-sil -o /dev/null -verify -verify-additional-prefix tns-

// REQUIRES: concurrency
// REQUIRES: asserts

class NotConcurrent { } // expected-note 12{{class 'NotConcurrent' does not conform to the 'Sendable' protocol}}
// expected-tns-allow-typechecker-note @-1 {{class 'NotConcurrent' does not conform to the 'Sendable' protocol}}

// ----------------------------------------------------------------------
// Sendable restriction on actor operations
// ----------------------------------------------------------------------

actor A1 {
  let localLet: NotConcurrent = NotConcurrent()
  func synchronous() -> NotConcurrent? { nil }
  func asynchronous(_: NotConcurrent?) async { }
}

@MainActor var booleanValue: Bool { false }

// Actor initializers and Sendable
actor A2 {
  var localVar: NotConcurrent

  init(value: NotConcurrent) {
    self.localVar = value
  }

  init(forwardSync value: NotConcurrent) {
    self.init(value: value)
  }

  init(delegatingSync value: NotConcurrent) {
    self.init(forwardSync: value)
  }

  init(valueAsync value: NotConcurrent) async {
    self.localVar = value
  }

  init(forwardAsync value: NotConcurrent) async {
    await self.init(valueAsync: value)
  }

  nonisolated init(nonisoAsync value: NotConcurrent, _ c: Int) async {
    if c == 0 {
      await self.init(valueAsync: value)
    } else {
      self.init(value: value)
    }
  }

  init(delegatingAsync value: NotConcurrent, _ c: Int) async {
    if c == 0 {
      await self.init(valueAsync: value)
    } else if c == 1 {
      self.init(value: value)
    } else if c == 2 {
      await self.init(forwardAsync: value)
    } else {
      self.init(delegatingSync: value)
    }
  }
}

func testActorCreation(value: NotConcurrent) async {
  _ = A2(value: value)
  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(value:)' risks causing data races between actor-isolated and task-isolated uses}}

  _ = await A2(valueAsync: value)
  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(valueAsync:)' risks causing data races between actor-isolated and task-isolated uses}}

  _ = A2(delegatingSync: value)
  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(delegatingSync:)' risks causing data races between actor-isolated and task-isolated uses}}

  _ = await A2(delegatingAsync: value, 9)
  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(delegatingAsync:_:)' risks causing data races between actor-isolated and task-isolated uses}}

  _ = await A2(nonisoAsync: value, 3)
  // expected-tns-warning @-1 {{sending 'value' risks causing data races}}
  // expected-tns-note @-2 {{sending task-isolated 'value' to actor-isolated initializer 'init(nonisoAsync:_:)' risks causing data races between actor-isolated and task-isolated uses}}
}

extension A1 {
  func testIsolation(other: A1) async {
    // All within the same actor domain, so the Sendable restriction
    // does not apply.
    _ = localLet
    _ = synchronous()
    _ = await asynchronous(nil)
    _ = self.localLet
    _ = self.synchronous()
    _ = await self.asynchronous(nil)

    // Across to a different actor, so Sendable restriction is enforced.
    _ = other.localLet // expected-warning{{non-sendable type 'NotConcurrent' of property 'localLet' cannot exit actor-isolated context}}
    // expected-warning@-1 {{expression is 'async' but is not marked with 'await'}}
    // expected-note@-2 {{property access is 'async'}}
    _ = await other.synchronous() // expected-tns-warning {{non-Sendable 'NotConcurrent?'-typed result can not be returned from actor-isolated instance method 'synchronous()' to actor-isolated context}}
    _ = await other.asynchronous(nil)
  }
}

// ----------------------------------------------------------------------
// Sendable restriction on global actor operations
// ----------------------------------------------------------------------
actor TestActor {}

@globalActor
struct SomeGlobalActor {
  static var shared: TestActor { TestActor() }
}

@SomeGlobalActor
let globalValue: NotConcurrent? = nil

@SomeGlobalActor
func globalSync(_: NotConcurrent?) {
}

@SomeGlobalActor
func globalAsync(_: NotConcurrent?) async {
  if await booleanValue {
    return
  }
  await globalAsync(globalValue) // both okay because we're in the actor
  globalSync(nil)
}

enum E {
  @SomeGlobalActor static let notSafe: NotConcurrent? = nil
}

func globalTest() async {
  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'}}
  // expected-note@+1 {{property access is 'async'}}
  let a = globalValue // expected-warning{{non-sendable type 'NotConcurrent?' of let 'globalValue' cannot exit global actor 'SomeGlobalActor'-isolated context}}
  await globalAsync(a) // expected-tns-warning {{sending 'a' risks causing data races}}
  // expected-tns-note @-1 {{sending global actor 'SomeGlobalActor'-isolated 'a' to global actor 'SomeGlobalActor'-isolated global function 'globalAsync' risks causing data races between global actor 'SomeGlobalActor'-isolated and local nonisolated uses}}
  await globalSync(a) // expected-tns-note {{access can happen concurrently}}

  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'}}
  // expected-note@+1 {{property access is 'async'}}
  let _ = E.notSafe // expected-warning{{non-sendable type 'NotConcurrent?' of static property 'notSafe' cannot exit global actor 'SomeGlobalActor'-isolated context}}

#if ALLOW_TYPECHECKER_ERRORS
  // expected-typechecker-error@+3 {{expression is 'async' but is not marked with 'await'}}
  // expected-typechecker-note@+2 {{call is 'async'}}
  // expected-typechecker-note@+1 {{property access is 'async'}}
  globalAsync(E.notSafe)

  // expected-typechecker-warning@-2 {{non-sendable type 'NotConcurrent?' of static property 'notSafe' cannot exit global actor 'SomeGlobalActor'-isolated context}}
#endif
}

struct HasSubscript {
  @SomeGlobalActor
  subscript (i: Int) -> NotConcurrent? { nil }
}

class ClassWithGlobalActorInits { // expected-tns-note 2{{class 'ClassWithGlobalActorInits' does not conform to the 'Sendable' protocol}}
  @SomeGlobalActor
  init(_: NotConcurrent) { }

  @SomeGlobalActor
  init() { }
}


@MainActor
func globalTestMain(nc: NotConcurrent) async {
  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'}}
  // expected-note@+1 {{property access is 'async'}}
  let a = globalValue // expected-warning {{non-sendable type 'NotConcurrent?' of let 'globalValue' cannot exit global actor 'SomeGlobalActor'-isolated context}}
  await globalAsync(a) // expected-tns-warning {{sending 'a' risks causing data races}}
  // expected-tns-note @-1 {{sending global actor 'SomeGlobalActor'-isolated 'a' to global actor 'SomeGlobalActor'-isolated global function 'globalAsync' risks causing data races between global actor 'SomeGlobalActor'-isolated and local main actor-isolated uses}}
  await globalSync(a) // expected-tns-note {{access can happen concurrently}}
  _ = await ClassWithGlobalActorInits(nc)
  // expected-tns-warning @-1 {{non-Sendable 'ClassWithGlobalActorInits'-typed result can not be returned from global actor 'SomeGlobalActor'-isolated initializer 'init(_:)' to main actor-isolated context}}
  // expected-tns-warning @-2 {{sending 'nc' risks causing data races}}
  // expected-tns-note @-3 {{sending main actor-isolated 'nc' to global actor 'SomeGlobalActor'-isolated initializer 'init(_:)' risks causing data races between global actor 'SomeGlobalActor'-isolated and main actor-isolated uses}}
  _ = await ClassWithGlobalActorInits() // expected-tns-warning {{non-Sendable 'ClassWithGlobalActorInits'-typed result can not be returned from global actor 'SomeGlobalActor'-isolated initializer 'init()' to main actor-isolated context}}
}

@SomeGlobalActor
func someGlobalTest(nc: NotConcurrent) {
  let hs = HasSubscript()
  let _ = hs[0] // okay
  _ = ClassWithGlobalActorInits(nc)
}

// ----------------------------------------------------------------------
// Sendable restriction on captures.
// ----------------------------------------------------------------------
func acceptNonConcurrent(_: () -> Void) { }
func acceptConcurrent(_: @Sendable () -> Void) { }

func testConcurrency() {
  let x = NotConcurrent()
  var y = NotConcurrent()
  y = NotConcurrent()
  acceptNonConcurrent {
    print(x) // okay
    print(y) // okay
  }
  acceptConcurrent {
    print(x) // expected-warning{{capture of 'x' with non-sendable type 'NotConcurrent' in a '@Sendable' closure}}
    print(y) // expected-warning{{capture of 'y' with non-sendable type 'NotConcurrent' in a '@Sendable' closure}}
    // expected-warning@-1{{reference to captured var 'y' in concurrently-executing code}}
  }
}

@preconcurrency func acceptUnsafeSendable(_ fn: @Sendable () -> Void) { }

func testUnsafeSendableNothing() {
  var x = 5
  acceptUnsafeSendable {
    x = 17 // expected-warning{{mutation of captured var 'x' in concurrently-executing code}}
  }
  print(x)
}

func testUnsafeSendableInAsync() async {
  var x = 5
  acceptUnsafeSendable {
    x = 17 // expected-warning{{mutation of captured var 'x' in concurrently-executing code}}
  }
  print(x)
}

// ----------------------------------------------------------------------
// Sendable restriction on key paths.
// ----------------------------------------------------------------------
class NC: Hashable { // expected-note 3{{class 'NC' does not conform to the 'Sendable' protocol}}
  func hash(into: inout Hasher) { }
  static func==(_: NC, _: NC) -> Bool { true }
}

class HasNC {
  var dict: [NC: Int] = [:]
}

func testKeyPaths(dict: [NC: Int], nc: NC) {
  _ = \HasNC.dict[nc] // expected-warning{{cannot form key path that captures non-sendable type 'NC'}}
}

// ----------------------------------------------------------------------
// Sendable restriction on nonisolated declarations.
// ----------------------------------------------------------------------
actor ANI {
  nonisolated let nc = NC() // expected-warning {{'nonisolated' can not be applied to variable with non-'Sendable' type 'NC'; this is an error in the Swift 6 language mode}}
  nonisolated func f() -> NC? { nil }
}

func testANI(ani: ANI) async {
  _ = ani.nc // expected-warning{{non-sendable type 'NC' of property 'nc' cannot exit nonisolated context}}
}

// ----------------------------------------------------------------------
// Sendable restriction on conformances.
// ----------------------------------------------------------------------
protocol AsyncProto {
  func asyncMethod(_: NotConcurrent) async
}

extension A1: AsyncProto {
  func asyncMethod(_: NotConcurrent) async { } // expected-warning{{non-sendable parameter type 'NotConcurrent' cannot be sent from caller of protocol requirement 'asyncMethod' into actor-isolated implementation}}
}

protocol MainActorProto {
  func asyncMainMethod(_: NotConcurrent) async
}

class SomeClass: MainActorProto {
  @SomeGlobalActor
  func asyncMainMethod(_: NotConcurrent) async { } // expected-warning{{non-sendable parameter type 'NotConcurrent' cannot be sent from caller of protocol requirement 'asyncMainMethod' into global actor 'SomeGlobalActor'-isolated implementation}}
}

// ----------------------------------------------------------------------
// Sendable restriction on concurrent functions.
// ----------------------------------------------------------------------

@Sendable func concurrentFunc() -> NotConcurrent? { nil }

// ----------------------------------------------------------------------
// No Sendable restriction on @Sendable function types.
// ----------------------------------------------------------------------
typealias CF = @Sendable () -> NotConcurrent?
typealias BadGenericCF<T> = @Sendable () -> T?
typealias GoodGenericCF<T: Sendable> = @Sendable () -> T? // okay

var concurrentFuncVar: (@Sendable (NotConcurrent) -> Void)? = nil // expected-warning{{var 'concurrentFuncVar' is not concurrency-safe because it is nonisolated global shared mutable state; this is an error in the Swift 6 language mode}}
// expected-note@-1 {{add '@MainActor' to make var 'concurrentFuncVar' part of global actor 'MainActor'}}
// expected-note@-2 {{disable concurrency-safety checks if accesses are protected by an external synchronization mechanism}}
// expected-note@-3 {{convert 'concurrentFuncVar' to a 'let' constant to make 'Sendable' shared state immutable}}

// ----------------------------------------------------------------------
// Sendable restriction on @Sendable closures.
// ----------------------------------------------------------------------
func acceptConcurrentUnary<T>(_: @Sendable (T) -> T) { }

func concurrentClosures<T>(_: T) { // expected-note{{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{26-26=: Sendable}}
  acceptConcurrentUnary { (x: T) in
    _ = x // ok
    acceptConcurrentUnary { _ in x } // expected-warning{{capture of 'x' with non-sendable type 'T' in a '@Sendable' closure}}
    let y: T? = nil
    return y!
  }
}

// ----------------------------------------------------------------------
// Sendable checking
// ----------------------------------------------------------------------
struct S1: Sendable {
  var nc: NotConcurrent // expected-warning{{stored property 'nc' of 'Sendable'-conforming struct 'S1' has non-sendable type 'NotConcurrent'}}
}

struct S2<T>: Sendable { // expected-note{{consider making generic parameter 'T' conform to the 'Sendable' protocol}} {{12-12=: Sendable}}
  var nc: T // expected-warning{{stored property 'nc' of 'Sendable'-conforming generic struct 'S2' has non-sendable type 'T'}}
}

struct S3<T> {
  var c: T
  var array: [T]
}

extension S3: Sendable where T: Sendable { }

enum E1: Sendable {
  case payload(NotConcurrent) // expected-warning{{associated value 'payload' of 'Sendable'-conforming enum 'E1' has non-sendable type 'NotConcurrent'}}
}

enum E2<T> {
  case payload(T)
}

extension E2: Sendable where T: Sendable { }

final class C1: Sendable {
  let nc: NotConcurrent? = nil // expected-warning{{stored property 'nc' of 'Sendable'-conforming class 'C1' has non-sendable type 'NotConcurrent?'}}
  var x: Int = 0 // expected-warning{{stored property 'x' of 'Sendable'-conforming class 'C1' is mutable}}
  let i: Int = 0
}

final class C2: Sendable {
  let x: Int = 0
}

class C3 { }

class C4: C3, @unchecked Sendable {
  var y: Int = 0 // okay
}

class C5: @unchecked Sendable {
  var x: Int = 0 // okay
}

// expected-warning@+1 {{class 'C6' must restate inherited '@unchecked Sendable' conformance}}{{13-13=, @unchecked Sendable}}
class C6: C5 {
  var y: Int = 0 // still okay, it's unsafe
}

class C6_Restated: C5, @unchecked Sendable {
  var y: Int = 0 // still okay, it's unsafe
}

class C6_Restated_Extension: C5 {
  var y: Int = 0 // still okay, it's unsafe
}

extension C6_Restated_Extension: @unchecked Sendable {}

final class C7<T>: Sendable { }

class C9: Sendable { } // expected-warning{{non-final class 'C9' cannot conform to 'Sendable'; use '@unchecked Sendable'}}

@available(*, unavailable)
extension HasUnavailableSendable : @unchecked Sendable { }

class HasUnavailableSendable {
}

class NoRestated: HasUnavailableSendable {} // okay

@globalActor
struct SomeActor {
  static let shared = A1()
}

class NotSendable {}

// actor-isolated mutable properties are valid
final class C10: Sendable { // expected-warning{{default initializer for 'C10' cannot be both nonisolated and main actor-isolated}}
  @MainActor var x = 0
  @MainActor var ns1 : NotSendable? // expected-note{{initializer for property 'ns1' is main actor-isolated}}
  @MainActor let ns : NotSendable? = nil
}

final class C14: Sendable { // expected-warning{{default initializer for 'C14' cannot be both nonisolated and global actor 'SomeActor'-isolated}}
  @SomeActor var y = 1
  @SomeActor var nc = NotConcurrent() // expected-note{{initializer for property 'nc' is global actor 'SomeActor'-isolated}}
  @SomeActor let nc1 = NotConcurrent()
}

extension NotConcurrent {
  func f() { }

  func test() {
    Task { // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
      f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
    }

    Task { // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
      self.f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
    }

    Task { [self] in // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
      f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
    }

    Task { [self] in // expected-tns-warning {{passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure}}
      self.f() // expected-tns-note {{closure captures 'self' which is accessible to code in the current task}}
    }
  }
}

// ----------------------------------------------------------------------
// @unchecked Sendable disabling checking
// ----------------------------------------------------------------------
struct S11: @unchecked Sendable {
  var nc: NotConcurrent // okay
}

struct S12<T>: @unchecked Sendable {
  var nc: T // okay
}

enum E11<T>: @unchecked Sendable {
  case payload(NotConcurrent) // okay
  case other(T) // okay
}

#if ALLOW_TYPECHECKER_ERRORS

class C11 { }

class C12: @unchecked C11 { } // expected-typechecker-error{{'unchecked' attribute cannot apply to non-protocol type 'C11'}}

protocol P { }

protocol Q: @unchecked Sendable { } // expected-typechecker-error{{'unchecked' attribute only applies in inheritance clauses}}

typealias TypeAlias1 = @unchecked P // expected-typechecker-error{{'unchecked' attribute only applies in inheritance clauses}}

#endif

// ----------------------------------------------------------------------
// UnsafeSendable historical name
// ----------------------------------------------------------------------
enum E12<T>: UnsafeSendable { // expected-warning{{'UnsafeSendable' is deprecated: Use @unchecked Sendable instead}}
  case payload(NotConcurrent) // okay
  case other(T) // okay
}

// ----------------------------------------------------------------------
// @Sendable inference through optionals
// ----------------------------------------------------------------------
func testSendableOptionalInference(nc: NotConcurrent) {
  var fn: (@Sendable () -> Void)? = nil
  fn = {
    print(nc) // expected-warning{{capture of 'nc' with non-sendable type 'NotConcurrent' in a '@Sendable' closure}}
  }
  _ = fn
}