Generic type alias access level regression [4.2 04/30/2018]

lib/AST/DeclContext.cpp

@@ -821,6 +821,9 @@ IterableDeclContext::castDeclToIterableDeclContext(const Decl *D) {
 /// declaration or extension, the supplied context is returned.
 static const DeclContext *
 getPrivateDeclContext(const DeclContext *DC, const SourceFile *useSF) {
+  if (DC->getASTContext().isSwiftVersion3())
+    return DC;
+
   auto NTD = DC->getAsNominalTypeOrNominalTypeExtensionContext();
   if (!NTD)
     return DC;

lib/Sema/TypeCheckDecl.cpp

@@ -1408,8 +1408,7 @@ class TypeAccessScopeChecker : private TypeWalker, AccessScopeChecker {
       return Action::Stop;
 
     if (!CanonicalizeParentTypes) {
-      return isa<NameAliasType>(T.getPointer()) ? Action::SkipChildren
-                                                     : Action::Continue;
+      return Action::Continue;
     }
 
     Type nominalParentTy;

test/Compatibility/accessibility_private.swift

@@ -171,8 +171,10 @@ extension Container {
 extension Container {
   private struct VeryPrivateStruct { // expected-note * {{type declared here}}
     private typealias VeryPrivateType = Int // expected-note * {{type declared here}}
+    private struct VeryPrivateInnerStruct {}
     var privateVar: VeryPrivateType { fatalError() } // expected-warning {{property should be declared private because its type uses a private type}}
     var privateVar2 = VeryPrivateType() // expected-warning {{property should be declared private because its type 'Container.VeryPrivateStruct.VeryPrivateType' (aka 'Int') uses a private type}}
+    var privateVar3 = VeryPrivateInnerStruct() // expected-warning {{property should be declared private because its type 'Container.VeryPrivateStruct.VeryPrivateInnerStruct' uses a private type}}
     typealias PrivateAlias = VeryPrivateType // expected-warning {{type alias should be declared private because its underlying type uses a private type}}
     subscript(_: VeryPrivateType) -> Void { return () } // expected-warning {{subscript should be declared private because its index uses a private type}}
     func privateMethod(_: VeryPrivateType) -> Void {} // expected-warning {{method should be declared private because its parameter uses a private type}} {{none}}

test/Sema/accessibility_private.swift

@@ -171,8 +171,10 @@ extension Container {
 extension Container {
   private struct VeryPrivateStruct { // expected-note * {{type declared here}}
     private typealias VeryPrivateType = Int // expected-note * {{type declared here}}
+    private struct VeryPrivateInnerStruct {}
     var privateVar: VeryPrivateType { fatalError() } // expected-error {{property must be declared private because its type uses a private type}}
     var privateVar2 = VeryPrivateType() // expected-error {{property must be declared private because its type 'Container.VeryPrivateStruct.VeryPrivateType' (aka 'Int') uses a private type}}
+    var privateVar3 = VeryPrivateInnerStruct() // expected-error {{property must be declared private because its type 'Container.VeryPrivateStruct.VeryPrivateInnerStruct' uses a private type}}
     typealias PrivateAlias = VeryPrivateType // expected-error {{type alias must be declared private because its underlying type uses a private type}}
     subscript(_: VeryPrivateType) -> Void { return () } // expected-error {{subscript must be declared private because its index uses a private type}}
     func privateMethod(_: VeryPrivateType) -> Void {} // expected-error {{method must be declared private because its parameter uses a private type}} {{none}}

test/Sema/accessibility_typealias.swift

@@ -90,3 +90,13 @@ public var failNested2: (_ x: (main.ActuallyPrivate) -> Void) -> Void = { _ in }
 public func failTest(x: ActuallyPrivate) {} // expected-error {{cannot be declared public}}
 public func failTest2(x: main.ActuallyPrivate) {} // expected-error {{cannot be declared public}}
 
+// Property has an inferred type, public alias with
+// private generic parameter bound.
+public struct PublicGeneric<T> {}
+
+public typealias GenericAlias<T> = PublicGeneric<T>
+
+fileprivate func makeAValue() -> GenericAlias<ActuallyPrivate> { }
+
+public var cannotBePublic = makeAValue()
+// expected-error@-1 {{variable cannot be declared public because its type 'GenericAlias<ActuallyPrivate>' (aka 'PublicGeneric<ActuallyPrivate>') uses a private type}}