AST: Get SPI status of PatternBindingDecl from anchoring VarDecl.

For property declarations, the `@_spi` attribute is attached to the VarDecl AST
node, rather than the PatternBindingDecl AST node, so the `isSPI()` query
should take this into account. Failing to do so caused the availability checker
to erroneously require that `@_spi` properties of types in `-library-level api`
libraries have availability annotations.

Resolves rdar://113587321.

Author: tshortli

lib/AST/Availability.cpp

@@ -747,6 +747,8 @@ ASTContext::getSwift5PlusAvailability(llvm::VersionTuple swiftVersion) {
       swiftVersion.getAsString());
 }
 
+// FIXME: Rename abstractSyntaxDeclForAvailableAttribute since it's useful
+// for more attributes than `@available`.
 const Decl *
 swift::abstractSyntaxDeclForAvailableAttribute(const Decl *ConcreteSyntaxDecl) {
   // This function needs to be kept in sync with its counterpart,

lib/AST/Module.cpp

@@ -3480,12 +3480,14 @@ bool Decl::isSPI() const {
 }
 
 ArrayRef<Identifier> Decl::getSPIGroups() const {
-  if (!isa<ValueDecl>(this) &&
-      !isa<ExtensionDecl>(this))
+  const Decl *D = abstractSyntaxDeclForAvailableAttribute(this);
+
+  if (!isa<ValueDecl>(D) &&
+      !isa<ExtensionDecl>(D))
     return ArrayRef<Identifier>();
 
   return evaluateOrDefault(getASTContext().evaluator,
-                           SPIGroupsRequest{ this },
+                           SPIGroupsRequest{ D },
                            ArrayRef<Identifier>());
 }
 

test/attr/attr_inlinable_available.swift

@@ -743,7 +743,7 @@ public struct PropertyWrapper<T> {
   public init(_ value: T) { self.wrappedValue = value }
 }
 
-public struct PublicStruct { // expected-note 13 {{add @available attribute}}
+public struct PublicStruct { // expected-note 15 {{add @available attribute}}
   // Public property declarations are exposed.
   public var aPublic: NoAvailable,
              bPublic: BeforeInliningTarget,
@@ -760,6 +760,44 @@ public struct PublicStruct { // expected-note 13 {{add @available attribute}}
              ePublicAvailBetween: AtDeploymentTarget, // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
              fPublicAvailBetween: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
 
+  @_spi(Private)
+  public var aSPI: NoAvailable,
+             bSPI: BeforeInliningTarget,
+             cSPI: AtInliningTarget,
+             dSPI: BetweenTargets,
+             eSPI: AtDeploymentTarget,
+             fSPI: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  @available(macOS, unavailable)
+  public var aUnavailable: NoAvailable {
+    NoAvailable()
+  }
+
+  @available(macOS, unavailable)
+  public var bUnavailable: BeforeInliningTarget {
+    BeforeInliningTarget()
+  }
+
+  @available(macOS, unavailable)
+  public var cUnavailable: AtInliningTarget {
+    AtInliningTarget()
+  }
+
+  @available(macOS, unavailable)
+  public var dUnavailable: BetweenTargets {
+    BetweenTargets()
+  }
+
+  @available(macOS, unavailable)
+  public var eUnavailable: AtDeploymentTarget {
+    AtDeploymentTarget()
+  }
+
+  @available(macOS, unavailable)
+  public var fUnavailable: AfterDeploymentTarget {
+    AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add 'if #available' version check}}
+  }
+
   // The inferred types of public properties are exposed.
   public var aPublicInferred = NoAvailable(),
              bPublicInferred = BeforeInliningTarget(),
@@ -1357,6 +1395,41 @@ enum InternalNoAvailableEnumWithTypeAliases { // expected-note {{add @available
   public typealias F = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}} expected-note {{add @available attribute to enclosing type alias}}
 }
 
+// MARK: - Enums with payloads
+
+public enum PublicNoAvailableEnumWithPayloads { // expected-note 5 {{add @available attribute to enclosing enum}}
+  case aNoAvailable(NoAvailable),
+       bNoAvailable(BeforeInliningTarget),
+       cNoAvailable(AtInliningTarget),
+       dNoAvailable(BetweenTargets), // expected-error {{'BetweenTargets' is only available in macOS 10.14.5 or newer; clients of 'Test' may have a lower deployment target}}
+       eNoAvailable(AtDeploymentTarget), // expected-error {{'AtDeploymentTarget' is only available in macOS 10.15 or newer; clients of 'Test' may have a lower deployment target}}
+       fNoAvailable(AfterDeploymentTarget) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  @available(macOS, introduced: 10.15)
+  case aAtDeploymentTarget(NoAvailable),
+       bAtDeploymentTarget(BeforeInliningTarget),
+       cAtDeploymentTarget(AtInliningTarget),
+       dAtDeploymentTarget(BetweenTargets),
+       eAtDeploymentTarget(AtDeploymentTarget),
+       fAtDeploymentTarget(AfterDeploymentTarget) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  @_spi(Private)
+  case aSPI(NoAvailable),
+       bSPI(BeforeInliningTarget),
+       cSPI(AtInliningTarget),
+       dSPI(BetweenTargets),
+       eSPI(AtDeploymentTarget),
+       fSPI(AfterDeploymentTarget) // expected-error {{'AfterDeploymentTarget' is only available in macOS 11 or newer}}
+
+  @available(macOS, unavailable)
+  case aUnavailable(NoAvailable),
+       bUnavailable(BeforeInliningTarget),
+       cUnavailable(AtInliningTarget),
+       dUnavailable(BetweenTargets),
+       eUnavailable(AtDeploymentTarget),
+       fUnavailable(AfterDeploymentTarget)
+}
+
 // MARK: - Class inheritance
 
 // FIXME: Duplicate 'add @available' emitted when classes are nested in a decl