Sema: Rationalize availability checking in unavailable contexts.

Correct several behaviors of availability checking in unavailable contexts that were inconsistent with the checking model: - Avoid diagnosing unintroduced and obsolted declarations in contexts that are unavailable in the same domain. - Diagnose unavailability normally in type signature contexts.
2025-12-14 20:36:38 +01:00 · 2025-08-07 18:00:49 -07:00
parent 35e1276c7b
commit 4d41db3b5d
13 changed files with 125 additions and 143 deletions
--- a/lib/AST/AvailabilityConstraint.cpp
+++ b/lib/AST/AvailabilityConstraint.cpp
@@ -172,28 +172,9 @@ static bool canIgnoreConstraintInUnavailableContexts(
    return true;

  case AvailabilityConstraint::Reason::Unintroduced:
-    switch (domain.getKind()) {
-    case AvailabilityDomain::Kind::Universal:
-    case AvailabilityDomain::Kind::SwiftLanguage:
-    case AvailabilityDomain::Kind::PackageDescription:
-    case AvailabilityDomain::Kind::Embedded:
-    case AvailabilityDomain::Kind::Custom:
-      return false;
-    case AvailabilityDomain::Kind::Platform:
-      // Platform availability only applies to the target triple that the
-      // binary is being compiled for. Since the same declaration can be
-      // potentially unavailable from a given context when compiling for one
-      // platform, but available from that context when compiling for a
-      // different platform, it is overly strict to enforce potential platform
-      // unavailability constraints in contexts that are unavailable to that
-      // platform.
-      return true;
-    }
-    return constraint.getDomain().isPlatform();
-
  case AvailabilityConstraint::Reason::UnavailableObsolete:
  case AvailabilityConstraint::Reason::UnavailableUnintroduced:
-    return false;
+    return domain.isVersioned();
  }
 }

--- a/lib/Sema/TypeCheckAccess.cpp
+++ b/lib/Sema/TypeCheckAccess.cpp
@@ -2073,11 +2073,6 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
    // Don't bother checking errors.
    if (type && type->hasError())
      return;
-    
-    // If the decl which references this type is unavailable on the current
-    // platform, don't diagnose the availability of the type.
-    if (Where.getAvailability().isUnavailable())
-      return;

    diagnoseTypeAvailability(typeRepr, type, context->getLoc(),
                             Where.withReason(reason), flags);
--- a/lib/Sema/TypeCheckAvailability.cpp
+++ b/lib/Sema/TypeCheckAvailability.cpp
@@ -1502,9 +1502,12 @@ static void diagnoseIfDeprecated(SourceRange ReferenceRange,
  // We match the behavior of clang to not report deprecation warnings
  // inside declarations that are themselves deprecated on all deployment
  // targets.
-  if (Availability.isDeprecated()) {
+  if (Availability.isDeprecated())
+    return;
+
+  // Skip diagnosing deprecated types in unavailable contexts.
+  if (Availability.isUnavailable() && isa<TypeDecl>(DeprecatedDecl))
    return;
-  }

  auto *ReferenceDC = Where.getDeclContext();
  auto &Context = ReferenceDC->getASTContext();
--- a/test/ASTGen/embedded_availability.swift
+++ b/test/ASTGen/embedded_availability.swift
@@ -11,7 +11,7 @@ public struct UnavailableInEmbedded {}

@available(*, unavailable, message: "always unavailable")
 public struct UniverallyUnavailable {}
-// expected-note@-1 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}
+// expected-note@-1 3 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}

@_unavailableInEmbedded
 public func unavailable_in_embedded() { }
@@ -43,7 +43,7 @@ public struct Available {}
 extension Available {
  public func unavailable_in_embedded_method( // expected-note {{'unavailable_in_embedded_method' has been explicitly marked unavailable here}}
    _ uie: UnavailableInEmbedded,
-    _ uu: UniverallyUnavailable,
+    _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
    _ a: Available,
  ) {
    unavailable_in_embedded()
@@ -67,7 +67,7 @@ public func available(
@_unavailableInEmbedded
 public func also_unavailable_in_embedded(
  _ uie: UnavailableInEmbedded, // OK
-  _ uu: UniverallyUnavailable, // OK
+  _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
  _ a: Available,
 ) {
  unavailable_in_embedded() // OK
--- a/test/Availability/availability_custom_domains.swift
+++ b/test/Availability/availability_custom_domains.swift
@@ -522,11 +522,11 @@ class DerivedLessAvailable: BaseAvailableInEnabledDomain { // expected-error {{'
 }

@available(EnabledDomain, unavailable)
-class DerivedUnavailable: BaseAvailableInEnabledDomain { }
+class DerivedUnavailable: BaseAvailableInEnabledDomain { } // expected-error {{'BaseAvailableInEnabledDomain' is only available in EnabledDomain}}

-// FIXME: This shouldn't be accepted
@available(DisabledDomain, unavailable)
-class DerivedUnavailable2: BaseAvailableInEnabledDomain { }
+class DerivedUnavailable2: BaseAvailableInEnabledDomain { } // expected-error {{'BaseAvailableInEnabledDomain' is only available in EnabledDomain}}
+// expected-note@-1 {{add '@available' attribute to enclosing class}}

@available(EnabledDomain)
@available(DisabledDomain, unavailable)
--- a/test/Availability/availability_target_min_inlining.swift
+++ b/test/Availability/availability_target_min_inlining.swift
@@ -350,7 +350,7 @@ public func alwaysUnavailable(
  _ = BetweenTargets()
  _ = AtDeploymentTarget()
  _ = AfterDeploymentTarget()
-  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedBetweenTargets()
  _ = Unavailable()
  
  if #available(macOS 11, *) {
@@ -630,7 +630,7 @@ public func spiDeployedUseNoAvailable( // expected-note 3 {{add '@available' att
  defer {
    _ = AtDeploymentTarget()
    _ = AfterDeploymentTarget()
-    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+    _ = ObsoletedBetweenTargets()
  }
  _ = NoAvailable()
  _ = BeforeInliningTarget()
@@ -638,12 +638,12 @@ public func spiDeployedUseNoAvailable( // expected-note 3 {{add '@available' att
  _ = BetweenTargets()
  _ = AtDeploymentTarget()
  _ = AfterDeploymentTarget()
-  _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _ = ObsoletedBetweenTargets()
  _ = Unavailable()

  if #available(macOS 11, *) {
    _ = AfterDeploymentTarget()
-    _ = ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+    _ = ObsoletedBetweenTargets()
  }
 }

@@ -930,7 +930,7 @@ public func defaultArgsUseUnavailable(
  _: Any = BetweenTargets.self,
  _: Any = AtDeploymentTarget.self,
  _: Any = AfterDeploymentTarget.self,
-  _: Any = ObsoletedBetweenTargets.self, // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+  _: Any = ObsoletedBetweenTargets.self,
  _: Any = Unavailable.self
 ) {}

@@ -1056,7 +1056,7 @@ public struct PublicStruct { // expected-note 21 {{add '@available' attribute}}

  @available(macOS, unavailable)
  public var gUnavailable: ObsoletedBetweenTargets {
-    ObsoletedBetweenTargets() // expected-error {{'ObsoletedBetweenTargets' is unavailable in macOS}}
+    ObsoletedBetweenTargets()
  }

  // The inferred types of public properties are exposed.
--- a/test/Availability/conformance_availability.swift
+++ b/test/Availability/conformance_availability.swift
@@ -70,7 +70,7 @@ public struct HasUnavailableConformance3 {}

@available(swift 12)
 extension HasUnavailableConformance3 : Horse {}
-// expected-note@-1 12{{conformance of 'HasUnavailableConformance3' to 'Horse' was introduced in Swift 12}}
+// expected-note@-1 6{{conformance of 'HasUnavailableConformance3' to 'Horse' was introduced in Swift 12}}

 func passUnavailableConformance3(x: HasUnavailableConformance3) {
  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
@@ -83,12 +83,12 @@ func passUnavailableConformance3(x: HasUnavailableConformance3) {

@available(swift 12)
 func passUnavailableConformance3a(x: HasUnavailableConformance3) {
-  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  takesHorseExistential(x) // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  x.giddyUp() // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  _ = x.isGalloping // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  _ = x[keyPath: \.isGalloping] // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
-  _ = UsesHorse<HasUnavailableConformance3>.self // expected-error {{conformance of 'HasUnavailableConformance3' to 'Horse' is unavailable}}
+  takesHorse(x)
+  takesHorseExistential(x)
+  x.giddyUp()
+  _ = x.isGalloping
+  _ = x[keyPath: \.isGalloping]
+  _ = UsesHorse<HasUnavailableConformance3>.self
 }

 // Platform obsoleted
@@ -96,7 +96,7 @@ public struct HasUnavailableConformance4 {}

@available(macOS, obsoleted: 10.1)
 extension HasUnavailableConformance4 : Horse {}
-// expected-note@-1 12{{conformance of 'HasUnavailableConformance4' to 'Horse' was obsoleted in macOS 10.1}}
+// expected-note@-1 6{{conformance of 'HasUnavailableConformance4' to 'Horse' was obsoleted in macOS 10.1}}

 func passUnavailableConformance4(x: HasUnavailableConformance4) {
  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
@@ -109,12 +109,12 @@ func passUnavailableConformance4(x: HasUnavailableConformance4) {

@available(macOS, obsoleted: 10.1)
 func passUnavailableConformance4a(x: HasUnavailableConformance4) {
-  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
-  takesHorseExistential(x) // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
-  x.giddyUp() // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
-  _ = x.isGalloping // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable}}
-  _ = x[keyPath: \.isGalloping] // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable}}
-  _ = UsesHorse<HasUnavailableConformance4>.self // expected-error {{conformance of 'HasUnavailableConformance4' to 'Horse' is unavailable in macOS}}
+  takesHorse(x)
+  takesHorseExistential(x)
+  x.giddyUp()
+  _ = x.isGalloping
+  _ = x[keyPath: \.isGalloping]
+  _ = UsesHorse<HasUnavailableConformance4>.self
 }

 // Swift obsoleted
@@ -122,7 +122,7 @@ public struct HasUnavailableConformance5 {}

@available(swift, obsoleted: 4)
 extension HasUnavailableConformance5 : Horse {}
-// expected-note@-1 12{{conformance of 'HasUnavailableConformance5' to 'Horse' was obsoleted in Swift 4}}
+// expected-note@-1 6{{conformance of 'HasUnavailableConformance5' to 'Horse' was obsoleted in Swift 4}}

 func passUnavailableConformance5(x: HasUnavailableConformance5) {
  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
@@ -135,12 +135,12 @@ func passUnavailableConformance5(x: HasUnavailableConformance5) {

@available(swift, obsoleted: 4)
 func passUnavailableConformance5a(x: HasUnavailableConformance5) {
-  takesHorse(x) // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  takesHorseExistential(x) // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  x.giddyUp() // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  _ = x.isGalloping // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  _ = x[keyPath: \.isGalloping] // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
-  _ = UsesHorse<HasUnavailableConformance5>.self // expected-error {{conformance of 'HasUnavailableConformance5' to 'Horse' is unavailable}}
+  takesHorse(x)
+  takesHorseExistential(x)
+  x.giddyUp()
+  _ = x.isGalloping
+  _ = x[keyPath: \.isGalloping]
+  _ = UsesHorse<HasUnavailableConformance5>.self
 }

 // Unavailable with message
--- a/test/Availability/property_wrapper_availability.swift
+++ b/test/Availability/property_wrapper_availability.swift
@@ -23,7 +23,7 @@ struct DeprecatedWrapper<T> {

@available(*, unavailable)
@propertyWrapper
-struct UnavailableWrapper<T> { // expected-note 8 {{'UnavailableWrapper' has been explicitly marked unavailable here}}
+struct UnavailableWrapper<T> { // expected-note 12 {{'UnavailableWrapper' has been explicitly marked unavailable here}}
  var wrappedValue: T
 }

@@ -113,8 +113,8 @@ struct UnavailableOnMacOSStruct {
  @DeprecatedWrapper var deprecatedExplicit: S
  @DeprecatedWrapper var deprecatedInferred = S()

-  @UnavailableWrapper var unavailableExplicit: S
-  @UnavailableWrapper var unavailableInferred = S()
+  @UnavailableWrapper var unavailableExplicit: S // expected-error {{'UnavailableWrapper' is unavailable}}
+  @UnavailableWrapper var unavailableInferred = S() // expected-error {{'UnavailableWrapper' is unavailable}}

  @WrappedValueUnavailableOnMacOS var unavailableWrappedValue: S
  @WrappedValueAvailable51 var wrappedValueAavailable51: S
@@ -175,14 +175,14 @@ func unavailableOnMacOSFunc(
  @AlwaysAvailableWrapper _ alwaysAvailable: S,
  @Available51Wrapper _ available51: S,
  @DeprecatedWrapper _ deprecated: S,
-  @UnavailableWrapper _ unavailable: S,
+  @UnavailableWrapper _ unavailable: S, // expected-error {{'UnavailableWrapper' is unavailable}}
  @WrappedValueUnavailableOnMacOS _ unavailableWrappedValue: S,
  @WrappedValueAvailable51 _ wrappedValueAavailable51: S
 ) {
  @AlwaysAvailableWrapper var alwaysAvailableLocal = S()
  @Available51Wrapper var available51Local = S()
  @DeprecatedWrapper var deprecatedLocal = S()
-  @UnavailableWrapper var unavailableLocal = S()
+  @UnavailableWrapper var unavailableLocal = S() // expected-error {{'UnavailableWrapper' is unavailable}}
  @WrappedValueUnavailableOnMacOS var unavailableWrappedValueLocal = S()
  @WrappedValueAvailable51 var wrappedValueAavailable51 = S()
 }
--- a/test/attr/attr_availability_transitive.swift
+++ b/test/attr/attr_availability_transitive.swift
@@ -27,13 +27,13 @@ func never() -> NeverAvailable { // expected-note * {{'never()' has been explici
@available(swift, obsoleted: 4)
@discardableResult
 func unavailableInSwift4() -> UnavailableInSwift4 { // expected-note * {{'unavailableInSwift4()' was obsoleted in Swift 4}}
-  UnavailableInSwift4() // expected-error {{'UnavailableInSwift4' is unavailable}}
+  UnavailableInSwift4()
 }

@available(swift, introduced: 99)
@discardableResult
 func availableInFutureSwift() -> AvailableInFutureSwift { // expected-note * {{'availableInFutureSwift()' was introduced in Swift 99}}
-  AvailableInFutureSwift() // expected-error {{'AvailableInFutureSwift' is unavailable}}
+  AvailableInFutureSwift()
 }

 // MARK: Global functions
@@ -59,34 +59,34 @@ func never_available_func(
 ) {
  always()
  never() // expected-error {{'never()' is unavailable}}
-  unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  unavailableInSwift4()
+  availableInFutureSwift()
 }

@available(swift, obsoleted: 4)
 func unavailable_in_swift4_func(
  _: AlwaysAvailable,
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  _: UnavailableInSwift4,
  _: AvailableInFutureSwift,
 ) {
  always()
  never() // expected-error {{'never()' is unavailable}}
-  unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  unavailableInSwift4()
+  availableInFutureSwift()
 }

@available(swift, introduced: 99)
 func introduced_in_future_swift_func(
  _: AlwaysAvailable,
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  _: UnavailableInSwift4,
  _: AvailableInFutureSwift,
 ) {
  always()
  never() // expected-error {{'never()' is unavailable}}
-  unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  unavailableInSwift4()
+  availableInFutureSwift()
 }

 // MARK: Global vars
@@ -112,34 +112,34 @@ var never_var: (
 ) = (
  always(),
  never(), // expected-error {{'never()' is unavailable}}
-  unavailableInSwift4(), // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable}}
+  unavailableInSwift4(),
+  availableInFutureSwift(),
 )

@available(swift, obsoleted: 4)
 var unavailable_in_swift4_var: (
  AlwaysAvailable,
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  UnavailableInSwift4,
  AvailableInFutureSwift
 ) = (
  always(),
  never(), // expected-error {{'never()' is unavailable}}
-  unavailableInSwift4(), // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable}}
+  unavailableInSwift4(),
+  availableInFutureSwift(),
 )

@available(swift, introduced: 99)
 var available_in_future_swift_var: (
  AlwaysAvailable,
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  UnavailableInSwift4,
  AvailableInFutureSwift
 ) = (
  always(),
  never(), // expected-error {{'never()' is unavailable}}
-  unavailableInSwift4(), // expected-error {{'unavailableInSwift4()' is unavailable}}
-  availableInFutureSwift(), // expected-error {{'availableInFutureSwift()' is unavailable}}
+  unavailableInSwift4(),
+  availableInFutureSwift(),
 )


@@ -156,27 +156,29 @@ struct AlwaysAvailableContainer {
 }

@available(*, unavailable)
-struct NeverAvailableContainer { // expected-note {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
+struct NeverAvailableContainer { // expected-note 3 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
  let always_var: AlwaysAvailable = always()
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
-  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4()
+  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift()
 }

@available(swift, obsoleted: 4)
 struct UnavailableInSwift4Container { // expected-note {{'UnavailableInSwift4Container' was obsoleted in Swift 4}}
  let always_var: AlwaysAvailable = always()
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
-  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
+  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4()
+  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift()
 }

@available(swift, introduced: 99)
 struct AvailableInFutureSwiftContainer { // expected-note {{'AvailableInFutureSwiftContainer' was introduced in Swift 99}}
  let always_var: AlwaysAvailable = always()
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
-  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
+  let unavailable_in_swift4_var: UnavailableInSwift4 = unavailableInSwift4()
+  let available_in_future_swift_var: AvailableInFutureSwift = availableInFutureSwift()
 }

 // MARK: Extensions
@@ -198,7 +200,7 @@ extension AvailableInFutureSwiftContainer {}
@available(swift, obsoleted: 4)
 extension AlwaysAvailableContainer {}
@available(swift, obsoleted: 4)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
@available(swift, obsoleted: 4)
 extension UnavailableInSwift4Container {}
@available(swift, obsoleted: 4)
@@ -207,7 +209,7 @@ extension AvailableInFutureSwiftContainer {}
@available(swift, introduced: 99)
 extension AlwaysAvailableContainer {}
@available(swift, introduced: 99)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
@available(swift, introduced: 99)
 extension UnavailableInSwift4Container {}
@available(swift, introduced: 99)
@@ -227,8 +229,8 @@ extension ExtendMe {
  ) {
    always()
    never() // expected-error {{'never()' is unavailable}}
-    unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    unavailableInSwift4()
+    availableInFutureSwift()
  }

  @available(*, unavailable)
@@ -240,8 +242,8 @@ extension ExtendMe {
  ) {
    always()
    never() // expected-error {{'never()' is unavailable}}
-    unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    unavailableInSwift4()
+    availableInFutureSwift()
  }

  @available(swift, obsoleted: 4)
@@ -253,8 +255,8 @@ extension ExtendMe {
  ) {
    always()
    never() // expected-error {{'never()' is unavailable}}
-    unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    unavailableInSwift4()
+    availableInFutureSwift()
  }

  @available(swift, introduced: 99)
@@ -266,10 +268,9 @@ extension ExtendMe {
  ) {
    always()
    never() // expected-error {{'never()' is unavailable}}
-    unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    unavailableInSwift4()
+    availableInFutureSwift()
  }
-
 }

@available(swift, obsoleted: 4)
@@ -285,8 +286,8 @@ extension ExtendMe {
  ) {
    always()
    never() // expected-error {{'never()' is unavailable}}
-    unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    unavailableInSwift4()
+    availableInFutureSwift()
  }
 }

@@ -303,8 +304,8 @@ extension ExtendMe {
  ) {
    always()
    never() // expected-error {{'never()' is unavailable}}
-    unavailableInSwift4() // expected-error {{'unavailableInSwift4()' is unavailable}}
-    availableInFutureSwift() // expected-error {{'availableInFutureSwift()' is unavailable}}
+    unavailableInSwift4()
+    availableInFutureSwift()
  }
 }

--- a/test/attr/attr_availability_transitive_osx.swift
+++ b/test/attr/attr_availability_transitive_osx.swift
@@ -96,7 +96,7 @@ func never_available_func(
@available(OSX, unavailable)
 func osx_func(
  _: AlwaysAvailable,
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  _: OSXFutureAvailable,
  _: OSXUnavailable,
  _: MultiPlatformUnavailable,
@@ -166,7 +166,7 @@ var never_var: (
@available(OSX, unavailable)
 var osx_var: (
  AlwaysAvailable,
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  OSXFutureAvailable,
  OSXUnavailable,
  MultiPlatformUnavailable,
@@ -213,7 +213,7 @@ struct AlwaysAvailableContainer { // expected-note 2 {{add '@available' attribut
 }

@available(*, unavailable)
-struct NeverAvailableContainer { // expected-note 2 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
+struct NeverAvailableContainer { // expected-note 3 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
  let always_var: AlwaysAvailable = always()
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
  let osx_future_var: OSXFutureAvailable = osx_future()
@@ -226,6 +226,7 @@ struct NeverAvailableContainer { // expected-note 2 {{'NeverAvailableContainer'
 struct OSXUnavailableContainer { // expected-note 2 {{'OSXUnavailableContainer' has been explicitly marked unavailable here}}
  let always_var: AlwaysAvailable = always()
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
  let osx_future_var: OSXFutureAvailable = osx_future()
  let osx_var: OSXUnavailable = osx()
  let osx_ios_var: MultiPlatformUnavailable = osx_ios()
@@ -265,7 +266,7 @@ extension OSXAppExtensionsUnavailableContainer {}
@available(OSX, unavailable)
 extension AlwaysAvailableContainer {}
@available(OSX, unavailable)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
@available(OSX, unavailable)
 extension OSXUnavailableContainer {}
@available(OSX, unavailable)
@@ -366,7 +367,7 @@ extension ExtendMe {

  func osx_extension_available_method( // expected-note * {{add '@available' attribute to enclosing instance method}}
    _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXFutureAvailable,
    _: OSXUnavailable,
    _: MultiPlatformUnavailable,
@@ -400,7 +401,7 @@ extension ExtendMe {
  @available(OSX, unavailable)
  func osx_extension_osx_method(
    _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXFutureAvailable,
    _: OSXUnavailable,
    _: MultiPlatformUnavailable,
@@ -417,7 +418,7 @@ extension ExtendMe {
  @available(OSXApplicationExtension, unavailable)
  func osx_extension_osx_app_extension_method(
    _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXFutureAvailable,
    _: OSXUnavailable,
    _: MultiPlatformUnavailable,
@@ -476,7 +477,7 @@ extension ExtendMe { // expected-note * {{add '@available' attribute to enclosin
  @available(OSX, unavailable)
  func osx_app_extension_extension_osx_method(
    _: AlwaysAvailable,
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXFutureAvailable,
    _: OSXUnavailable,
    _: MultiPlatformUnavailable,
@@ -522,7 +523,7 @@ func available_func_call_extension_methods(_ e: ExtendMe) { // expected-note {{a
 }

@available(OSX, obsoleted: 10.9)
-struct OSXObsoleted {} // expected-note 4 {{'OSXObsoleted' was obsoleted in macOS 10.9}}
+struct OSXObsoleted {}

@available(OSX, unavailable)
@available(OSX, introduced: 99)
@@ -549,16 +550,15 @@ func osx_unavailable_func(
  OSXUnavailableAndIntroducedInFutureSameAttribute,
  OSXIntroducedInFutureAndUnavailable
 ) {
-  // FIXME: [availability] Stop diagnosing obsoletion in an unavailable context.
  _ = OSXFutureAvailable()
-  _ = OSXObsoleted() // expected-error {{'OSXObsoleted' is unavailable in macOS}}
+  _ = OSXObsoleted()
  _ = OSXUnavailableAndIntroducedInFuture()
  _ = OSXUnavailableAndIntroducedInFutureSameAttribute()
  _ = OSXIntroducedInFutureAndUnavailable()

  func takesType<T>(_ t: T.Type) {}
  takesType(OSXFutureAvailable.self)
-  takesType(OSXObsoleted.self) // expected-error {{'OSXObsoleted' is unavailable in macOS}}
+  takesType(OSXObsoleted.self)
  takesType(OSXUnavailableAndIntroducedInFuture.self)
  takesType(OSXUnavailableAndIntroducedInFutureSameAttribute.self)
  takesType(OSXIntroducedInFutureAndUnavailable.self)
@@ -580,16 +580,15 @@ func osx_unavailable_and_introduced_func(
  OSXUnavailableAndIntroducedInFutureSameAttribute,
  OSXIntroducedInFutureAndUnavailable
 ) {
-  // FIXME: [availability] Stop diagnosing obsoletion in an unavailable context.
  _ = OSXFutureAvailable()
-  _ = OSXObsoleted() // expected-error {{'OSXObsoleted' is unavailable in macOS}}
+  _ = OSXObsoleted()
  _ = OSXUnavailableAndIntroducedInFuture()
  _ = OSXUnavailableAndIntroducedInFutureSameAttribute()
  _ = OSXIntroducedInFutureAndUnavailable()

  func takesType<T>(_ t: T.Type) {}
  takesType(OSXFutureAvailable.self)
-  takesType(OSXObsoleted.self) // expected-error {{'OSXObsoleted' is unavailable in macOS}}
+  takesType(OSXObsoleted.self)
  takesType(OSXUnavailableAndIntroducedInFuture.self)
  takesType(OSXUnavailableAndIntroducedInFutureSameAttribute.self)
  takesType(OSXIntroducedInFutureAndUnavailable.self)
--- a/test/attr/attr_availability_transitive_osx_appext.swift
+++ b/test/attr/attr_availability_transitive_osx_appext.swift
@@ -55,7 +55,7 @@ func never_available_func(

@available(OSX, unavailable)
 func osx_func(
-  _: NeverAvailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  _: OSXUnavailable,
  _: OSXAppExtensionsUnavailable
 ) {
@@ -66,8 +66,8 @@ func osx_func(

@available(OSXApplicationExtension, unavailable)
 func osx_extension_func(
-  _: NeverAvailable,
-  _: OSXUnavailable,
+  _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+  _: OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
  _: OSXAppExtensionsUnavailable
 ) {
  never() // expected-error {{'never()' is unavailable}}
@@ -100,7 +100,7 @@ var never_var: (

@available(OSX, unavailable)
 var osx_var: (
-  NeverAvailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
  OSXUnavailable,
  OSXAppExtensionsUnavailable
 ) = (
@@ -111,8 +111,8 @@ var osx_var: (

@available(OSXApplicationExtension, unavailable)
 var osx_extension_var: (
-  NeverAvailable,
-  OSXUnavailable,
+  NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+  OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
  OSXAppExtensionsUnavailable
 ) = (
  never(), // expected-error {{'never()' is unavailable}}
@@ -132,15 +132,16 @@ struct AlwaysAvailabileContainer {
 }

@available(*, unavailable)
-struct NeverAvailableContainer { // expected-note {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
+struct NeverAvailableContainer { // expected-note 3 {{'NeverAvailableContainer' has been explicitly marked unavailable here}}
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
  let osx_var: OSXUnavailable = osx()
  let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
 }

@available(OSX, unavailable)
-struct OSXUnavailableContainer { // expected-note {{'OSXUnavailableContainer' has been explicitly marked unavailable here}}
+struct OSXUnavailableContainer { // expected-note 2 {{'OSXUnavailableContainer' has been explicitly marked unavailable here}}
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
  let osx_var: OSXUnavailable = osx()
  let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
 }
@@ -148,7 +149,9 @@ struct OSXUnavailableContainer { // expected-note {{'OSXUnavailableContainer' ha
@available(OSXApplicationExtension, unavailable)
 struct OSXAppExtensionsUnavailableContainer { // expected-note {{'OSXAppExtensionsUnavailableContainer' has been explicitly marked unavailable here}}
  let never_var: NeverAvailable = never() // expected-error {{'never()' is unavailable}}
+  // expected-error@-1 {{'NeverAvailable' is unavailable}}
  let osx_var: OSXUnavailable = osx() // expected-error {{'osx()' is unavailable}}
+  // expected-error@-1 {{'OSXUnavailable' is unavailable in macOS}}
  let osx_extension_var: OSXAppExtensionsUnavailable = osx_extension()
 }

@@ -171,7 +174,7 @@ extension OSXAppExtensionsUnavailableContainer {}
@available(OSX, unavailable)
 extension AlwaysAvailabileContainer {}
@available(OSX, unavailable)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
@available(OSX, unavailable)
 extension OSXUnavailableContainer {}
@available(OSX, unavailable)
@@ -180,9 +183,9 @@ extension OSXAppExtensionsUnavailableContainer {}
@available(OSXApplicationExtension, unavailable)
 extension AlwaysAvailabileContainer {}
@available(OSXApplicationExtension, unavailable)
-extension NeverAvailableContainer {}
+extension NeverAvailableContainer {} // expected-error {{'NeverAvailableContainer' is unavailable}}
@available(OSXApplicationExtension, unavailable)
-extension OSXUnavailableContainer {}
+extension OSXUnavailableContainer {} // expected-error {{'OSXUnavailableContainer' is unavailable in macOS}}
@available(OSXApplicationExtension, unavailable)
 extension OSXAppExtensionsUnavailableContainer {}

@@ -256,7 +259,7 @@ extension ExtendMe {
  func osx_extension_osx_app_extension_method() {} // expected-note 2 {{'osx_extension_osx_app_extension_method()' has been explicitly marked unavailable here}}

  func osx_extension_available_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXUnavailable,
    _: OSXAppExtensionsUnavailable
  ) {
@@ -278,7 +281,7 @@ extension ExtendMe {

  @available(OSX, unavailable)
  func osx_extension_osx_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXUnavailable,
    _: OSXAppExtensionsUnavailable
  ) {
@@ -289,7 +292,7 @@ extension ExtendMe {

  @available(OSXApplicationExtension, unavailable)
  func osx_extension_osx_app_extension_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXUnavailable,
    _: OSXAppExtensionsUnavailable
  ) {
@@ -316,8 +319,8 @@ extension ExtendMe {
  func osx_app_extension_extension_osx_app_extension_method() {} // expected-note {{'osx_app_extension_extension_osx_app_extension_method()' has been explicitly marked unavailable here}}

  func osx_app_extension_extension_available_method(
-    _: NeverAvailable,
-    _: OSXUnavailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+    _: OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
    _: OSXAppExtensionsUnavailable
  ) {
    never() // expected-error {{'never()' is unavailable}}
@@ -338,7 +341,7 @@ extension ExtendMe {

  @available(OSX, unavailable)
  func osx_app_extension_extension_osx_method(
-    _: NeverAvailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
    _: OSXUnavailable,
    _: OSXAppExtensionsUnavailable
  ) {
@@ -349,8 +352,8 @@ extension ExtendMe {

  @available(OSXApplicationExtension, unavailable)
  func osx_app_extension_extension_osx_app_extension_method(
-    _: NeverAvailable,
-    _: OSXUnavailable,
+    _: NeverAvailable, // expected-error {{'NeverAvailable' is unavailable}}
+    _: OSXUnavailable, // expected-error {{'OSXUnavailable' is unavailable in macOS}}
    _: OSXAppExtensionsUnavailable
  ) {
    never() // expected-error {{'never()' is unavailable}}
--- a/test/embedded/availability.swift
+++ b/test/embedded/availability.swift
@@ -9,7 +9,7 @@ public struct UnavailableInEmbedded {}

@available(*, unavailable, message: "always unavailable")
 public struct UniverallyUnavailable {}
-// expected-note@-1 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}
+// expected-note@-1 3 {{'UniverallyUnavailable' has been explicitly marked unavailable here}}

@_unavailableInEmbedded
 public func unavailable_in_embedded() { }
@@ -41,7 +41,7 @@ public struct Available {}
 extension Available {
  public func unavailable_in_embedded_method( // expected-note {{'unavailable_in_embedded_method' has been explicitly marked unavailable here}}
    _ uie: UnavailableInEmbedded,
-    _ uu: UniverallyUnavailable,
+    _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
    _ a: Available,
  ) {
    unavailable_in_embedded()
@@ -65,7 +65,7 @@ public func available(
@_unavailableInEmbedded
 public func also_unavailable_in_embedded(
  _ uie: UnavailableInEmbedded, // OK
-  _ uu: UniverallyUnavailable, // OK
+  _ uu: UniverallyUnavailable, // expected-error {{'UniverallyUnavailable' is unavailable: always unavailable}}
  _ a: Available,
 ) {
  unavailable_in_embedded() // OK
--- a/validation-test/compiler_crashers_2_fixed/af7dc08992398ff.swift
+++ b/validation-test/compiler_crashers_2_fixed/af7dc08992398ff.swift
@@ -1,4 +1,4 @@
 // {"kind":"typecheck","signature":"constrainDomainInfos(llvm::SmallVectorImpl<swift::AvailabilityContext::DomainInfo>&, llvm::ArrayRef<swift::AvailabilityContext::DomainInfo>)","signatureAssert":"Assertion failed: (!isConstrained), function constrainDomainInfos"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
@available(*, unavailable) @available(_PackageDescription 3) func a {
  @available(_PackageDescription 5) func b