Sema: Fix isExported() for extension decls

lib/Sema/TypeCheckAvailability.cpp

@@ -78,6 +78,33 @@ bool swift::isExported(const ValueDecl *VD) {
   return false;
 }
 
+bool swift::isExported(const ExtensionDecl *ED) {
+  // An extension can only be exported if it extends an exported type.
+  if (auto *NTD = ED->getExtendedNominal()) {
+    if (!isExported(NTD))
+      return false;
+  }
+
+  // If there are any exported members then the extension is exported.
+  for (const Decl *D : ED->getMembers()) {
+    if (isExported(D))
+      return true;
+  }
+
+  // If the extension declares a conformance to a public protocol then the
+  // extension is exported.
+  auto protocols = ED->getLocalProtocols(ConformanceLookupKind::OnlyExplicit);
+  for (const ProtocolDecl *PD : protocols) {
+    AccessScope scope =
+      PD->getFormalAccessScope(/*useDC*/nullptr,
+                               /*treatUsableFromInlineAsPublic*/true);
+    if (scope.isPublic())
+      return true;
+  }
+
+  return false;
+}
+
 bool swift::isExported(const Decl *D) {
   if (auto *VD = dyn_cast<ValueDecl>(D)) {
     return isExported(VD);
@@ -91,10 +118,7 @@ bool swift::isExported(const Decl *D) {
     return false;
   }
   if (auto *ED = dyn_cast<ExtensionDecl>(D)) {
-    if (auto *NTD = ED->getExtendedNominal())
-      return isExported(NTD);
-
-    return false;
+    return isExported(ED);
   }
 
   return true;

lib/Sema/TypeCheckAvailability.h

@@ -183,9 +183,10 @@ class ExportContext {
   Optional<ExportabilityReason> getExportabilityReason() const;
 };
 
-/// Check if a public declaration is part of a module's API; that is, this
-/// will return false if the declaration is @_spi or @_implementationOnly.
+/// Check if a declaration is exported as part of a module's external interface.
+/// This includes public and @usableFromInline decls.
 bool isExported(const ValueDecl *VD);
+bool isExported(const ExtensionDecl *ED);
 bool isExported(const Decl *D);
 
 /// Diagnose uses of unavailable declarations in expressions.

test/Sema/availability_refinement_contexts_target_min_inlining.swift

@@ -0,0 +1,18 @@
+// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -target %target-next-stable-abi-triple -typecheck -dump-type-refinement-contexts -target-min-inlining-version min %s > %t.dump 2>&1
+// RUN: %FileCheck --strict-whitespace --check-prefix CHECK-%target-os %s < %t.dump
+
+// REQUIRES: swift_stable_abi
+
+// Verify that -target-min-inlining-version min implies the correct OS version
+// for the target OS.
+
+// CHECK-macosx: {{^}}(root versions=[10.10.0,+Inf)
+// CHECK-ios: {{^}}(root versions=[8.0,+Inf)
+// CHECK-tvos: {{^}}(root versions=[9.0,+Inf)
+// CHECK-watchos: {{^}}(root versions=[2.0,+Inf)
+
+// CHECK-macosx-NEXT: {{^}}  (resilience_boundary versions=[10.15.0,+Inf) decl=foo()
+// CHECK-ios-NEXT: {{^}}  (resilience_boundary versions=[13.0.0,+Inf) decl=foo()
+// CHECK-tvos-NEXT: {{^}}  (resilience_boundary versions=[13.0.0,+Inf) decl=foo()
+// CHECK-watchos-NEXT: {{^}}  (resilience_boundary versions=[6.0.0,+Inf) decl=foo()
+func foo() {}

test/Sema/availability_refinement_contexts_target_min_inlining_maccatalyst.swift

@@ -0,0 +1,15 @@
+// This test is the same as availability_refinement_contexts_target_min_inlining.swift
+// but with a different run invocation to specifically test macCatalyst because
+// currently there are no bots that run the tests with macCatalyst as the
+// target OS.
+
+// RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -target %target-cpu-apple-ios14.4-macabi -typecheck -dump-type-refinement-contexts -target-min-inlining-version min %s > %t.dump 2>&1
+// RUN: %FileCheck --strict-whitespace %s < %t.dump
+
+// REQUIRES: maccatalyst_support
+
+// Verify that -target-min-inlining-version min implies 13.1 on macCatalyst.
+
+// CHECK: {{^}}(root versions=[13.1,+Inf)
+// CHECK-NEXT: {{^}}  (resilience_boundary versions=[14.4.0,+Inf) decl=foo()
+func foo() {}

test/attr/attr_inlinable_available.swift

@@ -71,11 +71,42 @@ public struct AfterDeploymentTarget {
   @usableFromInline internal init() {}
 }
 
+// MARK: - Internal functions
 
+//
+// Both the signature and the body of internal functions should be typechecked
+// using the minimum deployment target.
+//
+
+internal func internalFn( // expected-note 3 {{add @available attribute to enclosing global function}}
+  _: NoAvailable,
+  _: BeforeInliningTarget,
+  _: AtInliningTarget,
+  _: BetweenTargets,
+  _: AtDeploymentTarget,
+  _: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in}}
+) {
+  defer {
+    _ = AtDeploymentTarget()
+    _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in}} expected-note {{add 'if #available'}}
+  }
+  _ = NoAvailable()
+  _ = BeforeInliningTarget()
+  _ = AtInliningTarget()
+  _ = BetweenTargets()
+  _ = AtDeploymentTarget()
+  _ = AfterDeploymentTarget() // expected-error {{'AfterDeploymentTarget' is only available in}} expected-note {{add 'if #available'}}
+
+  if #available(macOS 11, iOS 14, tvOS 14, watchOS 7, *) {
+    _ = AfterDeploymentTarget()
+  }
+}
+
+// MARK: - Resilient functions
 
 //
-// Uses in resilient functions are based on the minimum deployment target
-// (i.e. the -target).
+// The body of a resilient function is typechecked using the minimum deployment
+// but the function's signature should be checked with the inlining target.
 //
 
 public func deployedUseNoAvailable( // expected-note 5 {{add @available attribute}}
@@ -224,9 +255,11 @@ public func deployedUseAfterDeploymentTarget(
 }
 
 
+// MARK: - @inlinable functions
 
 //
-// Uses in inlinable functions are based on the minimum inlining target
+// Both the bodies and signatures of inlinable functions need to be typechecked
+// using the minimum inlining target.
 //
 
 @inlinable public func inlinedUseNoAvailable( // expected-note 8 {{add @available attribute}}
@@ -395,15 +428,8 @@ public func deployedUseAfterDeploymentTarget(
   _ = AfterDeploymentTarget()
 }
 
-//
-// Edge cases.
-//
-
-// Internal functions should use the minimum deployment target.
 
-internal func fn() {
-  _ = AtDeploymentTarget()
-}
+// MARK: - @_alwaysEmitIntoClient functions
 
 // @_alwaysEmitIntoClient acts like @inlinable.
 
@@ -437,6 +463,9 @@ internal func fn() {
   }
 }
 
+
+// MARK: - @_backDeploy functions
+
 // @_backDeploy acts like @inlinable.
 
 @available(macOS 10.10, iOS 8.0, tvOS 9.0, watchOS 2.0, *)
@@ -471,6 +500,9 @@ public func backDeployedToInliningTarget(
   }
 }
 
+
+// MARK: - Default arguments
+
 // Default arguments act like @inlinable.
 
 public func defaultArgsUseNoAvailable( // expected-note 3 {{add @available attribute}}
@@ -551,6 +583,116 @@ internal struct InternalStruct { // expected-note {{add @available attribute}}
   var fInternal: AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in}}
 }
 
+
+// MARK: - Extensions
+
+//
+// Extensions are externally visible if they extend a public type and (1) have
+// public members or (2) declare a conformance to a public protocol. Externally
+// visible extensions should be typechecked with the inlining target.
+//
+
+// OK, NoAvailable is always available, both internally and externally.
+extension NoAvailable {}
+extension NoAvailable {
+  public func publicFunc1() {}
+}
+
+// OK, no public members and BetweenTargets is always available internally.
+extension BetweenTargets {}
+
+// OK, no public members and BetweenTargets is always available internally.
+extension BetweenTargets {
+  internal func internalFunc1() {}
+  private func privateFunc1() {}
+  fileprivate func fileprivateFunc1() {}
+}
+
+// expected-error@+1 {{'BetweenTargets' is only available in}} expected-note@+1 {{add @available attribute to enclosing extension}}
+extension BetweenTargets {
+  public func publicFunc1() {}
+}
+
+// expected-error@+1 {{'BetweenTargets' is only available in}} expected-note@+1 {{add @available attribute to enclosing extension}}
+extension BetweenTargets {
+  @usableFromInline
+  internal func usableFromInlineFunc1() {}
+}
+
+// expected-error@+1 {{'BetweenTargets' is only available in}} expected-note@+1 {{add @available attribute to enclosing extension}}
+extension BetweenTargets {
+  internal func internalFunc2() {}
+  private func privateFunc2() {}
+  fileprivate func fileprivateFunc2() {}
+  public func publicFunc2() {}
+}
+
+// Same availability as BetweenTargets but internal instead of public.
+@available(macOS 10.14.5, iOS 12.3, tvOS 12.3, watchOS 5.3, *)
+internal struct BetweenTargetsInternal {}
+
+// OK, extensions on internal types are never visible externally.
+extension BetweenTargetsInternal {}
+extension BetweenTargetsInternal {
+  public func publicFunc() {}
+}
+
+// expected-error@+1 {{'AfterDeploymentTarget' is only available in}} expected-note@+1 {{add @available attribute to enclosing extension}}
+extension AfterDeploymentTarget {}
+
+// expected-error@+1 {{'AfterDeploymentTarget' is only available in}} expected-note@+1 {{add @available attribute to enclosing extension}}
+extension AfterDeploymentTarget {
+  internal func internalFunc1() {}
+  private func privateFunc1() {}
+  fileprivate func fileprivateFunc1() {}
+}
+
+// expected-error@+1 {{'AfterDeploymentTarget' is only available in}} expected-note@+1 {{add @available attribute to enclosing extension}}
+extension AfterDeploymentTarget {
+  public func publicFunc1() {}
+}
+
+
+// MARK: Protocol conformances
+
+internal protocol InternalProto {}
+
+extension NoAvailable: InternalProto {}
+extension BeforeInliningTarget: InternalProto {}
+extension AtInliningTarget: InternalProto {}
+extension BetweenTargets: InternalProto {}
+extension AtDeploymentTarget: InternalProto {}
+extension AfterDeploymentTarget: InternalProto {} // expected-error {{'AfterDeploymentTarget' is only available in}} expected-note {{add @available attribute to enclosing extension}}
+
+public protocol PublicProto {}
+
+extension NoAvailable: PublicProto {}
+extension BeforeInliningTarget: PublicProto {}
+extension AtInliningTarget: PublicProto {}
+extension BetweenTargets: PublicProto {} // expected-error {{'BetweenTargets' is only available in}} expected-note {{add @available attribute to enclosing extension}}
+extension AtDeploymentTarget: PublicProto {} // expected-error {{'AtDeploymentTarget' is only available in}} expected-note {{add @available attribute to enclosing extension}}
+extension AfterDeploymentTarget: PublicProto {} // expected-error {{'AfterDeploymentTarget' is only available in}} expected-note {{add @available attribute to enclosing extension}}
+
+
+// MARK: - Type aliases
+
+public typealias PublicNoAvailableAlias = NoAvailable
+public typealias PublicBeforeInliningTargetAlias = BeforeInliningTarget
+public typealias PublicAtInliningTargetAlias = AtInliningTarget
+public typealias PublicBetweenTargetsAlias = BetweenTargets // expected-error {{'BetweenTargets' is only available in}}
+public typealias PublicAtDeploymentTargetAlias = AtDeploymentTarget // expected-error {{'AtDeploymentTarget' is only available in}}
+public typealias PublicAfterDeploymentTargetAlias = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in}}
+
+typealias InternalNoAvailableAlias = NoAvailable
+typealias InternalBeforeInliningTargetAlias = BeforeInliningTarget
+typealias InternalAtInliningTargetAlias = AtInliningTarget
+typealias InternalBetweenTargetsAlias = BetweenTargets
+typealias InternalAtDeploymentTargetAlias = AtDeploymentTarget
+typealias InternalAfterDeploymentTargetAlias = AfterDeploymentTarget // expected-error {{'AfterDeploymentTarget' is only available in}}
+
+
+// MARK: - Top-level code
+
 // Top-level code, if somehow present in a resilient module, is treated like
 // a non-inlinable function.
 defer {