Serialization: Handle enum cases in ExternallyAccessibleDeclVisitor.

Author: tshortli

lib/Serialization/Serialization.cpp

@@ -3416,9 +3416,20 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     UNREACHABLE(IfConfig);
     UNREACHABLE(PrecedenceGroup);
     UNREACHABLE(Operator);
-    UNREACHABLE(EnumCase);
 
 #undef UNREACHABLE
+
+    // Uninteresting decls are always considered external. A kind of decl might
+    // always be external if it is declared at the top level and access control
+    // does not apply to it. Or, a kind of decl could be considered always
+    // external because it is only found nested within other declarations that
+    // have their own access level, in which case we assume that the declaration
+    // context has already been checked.
+#define UNINTERESTING(KIND)                                                    \
+  bool visit##KIND##Decl(const KIND##Decl *D) { return true; }
+    UNINTERESTING(EnumCase);
+
+#undef UNINTERESTING
   };
 
 public:

test/Inputs/lazy_typecheck.swift

@@ -168,6 +168,26 @@ class InternalClass: DoesNotExist { // expected-error {{cannot find type 'DoesNo
   init(x: DoesNotExist) {} // expected-error {{cannot find type 'DoesNotExist' in scope}}
 }
 
+public enum PublicEnum {
+  case a
+  case b(x: Int)
+
+  public func publicMethod() -> Int {
+    return true // expected-error {{cannot convert return expression of type 'Bool' to return type 'Int'}}
+  }
+
+  public var publicComputedVar: Int {
+    return true // expected-error {{cannot convert return expression of type 'Bool' to return type 'Int'}}
+  }
+}
+
+enum InternalEnum {
+  case bad(DoesNotExist) // expected-error {{cannot find type 'DoesNotExist' in scope}}
+
+  func method() -> DoesNotExist { // expected-error {{cannot find type 'DoesNotExist' in scope}}
+  }
+}
+
 // MARK: - Conformances
 
 public struct PublicStructConformingToPublicProto: PublicProto {
@@ -222,4 +242,3 @@ extension PublicGenericStruct where T == InternalStructForConstraint {}
 
 extension PublicGenericStruct: EmptyPublicProto where T == InternalStructForConstraint {}
 
-// FIXME: Test enums

test/Inputs/lazy_typecheck_client.swift

@@ -50,6 +50,16 @@ func testPublicClass() {
   PublicDerivedClass.publicClassMethod()
 }
 
+func testPublicEnum(_ e: PublicEnum) {
+  switch e {
+  case .a: ()
+  case .b(let x): let _: Int = x
+  }
+
+  let _: Int = e.publicMethod()
+  let _: Int = e.publicComputedVar
+}
+
 func testConformances() {
   let array: [any PublicProto] = [
     PublicStructConformingToPublicProto(),

test/ModuleInterface/lazy-typecheck.swift

@@ -69,6 +69,14 @@
 // CHECK:         override public init(x: Swift.Int)
 // CHECK:         deinit
 // CHECK:       }
+// CHECK:       public enum PublicEnum {
+// CHECK:         case a
+// CHECK:         case b(x: Swift.Int)
+// CHECK:         public func publicMethod() -> Swift.Int
+// CHECK:         public var publicComputedVar: Swift.Int {
+// CHECK-NEXT:      get
+// CHECK-NEXT:    }
+// CHECK:       }
 // CHECK:       public struct PublicStructConformingToPublicProto : lazy_typecheck.PublicProto {
 // CHECK:         public init()
 // CHECK:         public func req() -> Swift.Int

test/TBD/lazy-typecheck.swift

@@ -56,7 +56,12 @@ exports:
                        '_$s14lazy_typecheck034PublicStructIndirectlyConformingToC5ProtoVMa',
                        '_$s14lazy_typecheck034PublicStructIndirectlyConformingToC5ProtoVMn',
                        '_$s14lazy_typecheck034PublicStructIndirectlyConformingToC5ProtoVN',
-                       '_$s14lazy_typecheck10publicFuncSiyF', '_$s14lazy_typecheck11PublicClassC06publicD6MethodyyFZTj',
+                       '_$s14lazy_typecheck10PublicEnumO12publicMethodSiyF', '_$s14lazy_typecheck10PublicEnumO17publicComputedVarSivg',
+                       '_$s14lazy_typecheck10PublicEnumO17publicComputedVarSivpMV',
+                       '_$s14lazy_typecheck10PublicEnumO1ayA2CmFWC', '_$s14lazy_typecheck10PublicEnumO1byACSi_tcACmFWC',
+                       '_$s14lazy_typecheck10PublicEnumOMa', '_$s14lazy_typecheck10PublicEnumOMn',
+                       '_$s14lazy_typecheck10PublicEnumON', '_$s14lazy_typecheck10publicFuncSiyF',
+                       '_$s14lazy_typecheck11PublicClassC06publicD6MethodyyFZTj',
                        '_$s14lazy_typecheck11PublicClassC06publicD6MethodyyFZTq',
                        '_$s14lazy_typecheck11PublicClassC12publicMethodSiyFTj', '_$s14lazy_typecheck11PublicClassC12publicMethodSiyFTq',
                        '_$s14lazy_typecheck11PublicClassC14publicPropertySivMTj',