Allow overrides in @_objcImplementation extensions

include/swift/AST/Decl.h

@@ -2379,6 +2379,10 @@ class ValueDecl : public Decl {
   /// Asserts if this is not a member of a protocol.
   bool isProtocolRequirement() const;
 
+  /// Return true if this is a member implementation for an \c @_objcImplementation
+  /// extension.
+  bool isObjCMemberImplementation() const;
+
   void setUserAccessible(bool Accessible) {
     Bits.ValueDecl.IsUserAccessible = Accessible;
   }

include/swift/AST/DiagnosticsSema.def

@@ -1511,10 +1511,6 @@ ERROR(attr_objc_implementation_category_not_found,none,
 NOTE(attr_objc_implementation_fixit_remove_category_name,none,
      "remove arguments to implement the main '@interface' for this class",
      ())
-ERROR(attr_objc_implementation_no_objc_final,none,
-      "%0 %1 cannot be 'final' because Objective-C subclasses of %2 can "
-      "override it",
-      (DescriptiveDeclKind, ValueDecl *, ValueDecl *))
 
 ERROR(member_of_objc_implementation_not_objc_or_final,none,
       "%0 %1 does not match any %0 declared in the headers for %2; did you use "

lib/AST/ASTDumper.cpp

@@ -1458,6 +1458,7 @@ void ValueDecl::dumpRef(raw_ostream &os) const {
 
 void LLVM_ATTRIBUTE_USED ValueDecl::dumpRef() const {
   dumpRef(llvm::errs());
+  llvm::errs() << "\n";
 }
 
 void SourceFile::dump() const {

lib/AST/Decl.cpp

@@ -3739,18 +3739,29 @@ static bool checkAccessUsingAccessScopes(const DeclContext *useDC,
 /// Checks if \p VD is an ObjC member implementation:
 ///
 /// \li It's in an \c \@_objcImplementation extension
-/// \li It's \c \@objc
+/// \li It's not explicitly \c final
 /// \li Its access level is not \c private or \c fileprivate
 static bool
 isObjCMemberImplementation(const ValueDecl *VD,
                            llvm::function_ref<AccessLevel()> getAccessLevel) {
   if (auto ED = dyn_cast<ExtensionDecl>(VD->getDeclContext()))
-    if (ED->isObjCImplementation())
-      return VD->isObjC() && getAccessLevel() >= AccessLevel::Internal;
+    if (ED->isObjCImplementation() && !isa<TypeDecl>(VD)) {
+      auto attrDecl = isa<AccessorDecl>(VD)
+                    ? cast<AccessorDecl>(VD)->getStorage()
+                    : VD;
+      return !attrDecl->isFinal()
+                  && !attrDecl->getAttrs().hasAttribute<OverrideAttr>()
+                  && getAccessLevel() >= AccessLevel::Internal;
+    }
 
   return false;
 }
 
+bool ValueDecl::isObjCMemberImplementation() const {
+  return ::isObjCMemberImplementation(
+              this, [&]() { return this->getFormalAccess(); });
+}
+
 /// Checks if \p VD may be used from \p useDC, taking \@testable and \@_spi
 /// imports into account.
 ///

lib/AST/NameLookup.cpp

@@ -1701,11 +1701,24 @@ NominalTypeDecl::lookupDirect(ObjCSelector selector, bool isInstance) {
   return stored.Methods;
 }
 
+static bool inObjCImplExtension(AbstractFunctionDecl *newDecl) {
+  if (auto ext = dyn_cast<ExtensionDecl>(newDecl->getDeclContext()))
+    return ext->isObjCImplementation();
+  return false;
+}
+
 /// If there is an apparent conflict between \p newDecl and one of the methods
 /// in \p vec, should we diagnose it?
 static bool
 shouldDiagnoseConflict(NominalTypeDecl *ty, AbstractFunctionDecl *newDecl,
                        llvm::TinyPtrVector<AbstractFunctionDecl *> &vec) {
+  // Conflicts between member implementations and their interfaces, or
+  // inherited inits and their overrides in @_objcImpl extensions, are spurious.
+  if (newDecl->isObjCMemberImplementation()
+      || (isa<ConstructorDecl>(newDecl) && inObjCImplExtension(newDecl)
+          && newDecl->getAttrs().hasAttribute<OverrideAttr>()))
+    return false;
+
   // Are all conflicting methods imported from ObjC and in our ObjC half or a
   // bridging header? Some code bases implement ObjC methods in Swift even
   // though it's not exactly supported.

lib/Sema/TypeCheckDecl.cpp

@@ -811,22 +811,6 @@ IsFinalRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
   if (!cls)
     return false;
 
-  // Objective-C doesn't have a way to prevent overriding, so if this member
-  // is accessible from ObjC and it's possible to subclass its parent from ObjC,
-  // `final` doesn't make sense even when inferred.
-  //
-  // FIXME: This is technically true iff `!cls->hasKnownSwiftImplementation()`,
-  //        but modeling that would be source-breaking, so instead we only
-  //        enforce it in `@_objcImplementation extension`s.
-  if (auto ext = dyn_cast<ExtensionDecl>(decl->getDeclContext()))
-    if (ext->isObjCImplementation() && decl->isObjC()) {
-      if (explicitFinalAttr)
-        diagnoseAndRemoveAttr(decl, explicitFinalAttr,
-                              diag::attr_objc_implementation_no_objc_final,
-                              decl->getDescriptiveKind(), decl, cls);
-      return false;
-    }
-
   switch (decl->getKind()) {
     case DeclKind::Var: {
       // Properties are final if they are declared 'static' or a 'let'
@@ -854,6 +838,12 @@ IsFinalRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
           return true;
 
         if (VD->isLet()) {
+          // If this `let` is in an `@_objcImplementation extension`, don't
+          // infer `final` unless it is written explicitly.
+          auto ed = dyn_cast<ExtensionDecl>(VD->getDeclContext());
+          if (!explicitFinalAttr && ed && ed->isObjCImplementation())
+            return false;
+
           if (VD->getFormalAccess() == AccessLevel::Open) {
             auto &context = decl->getASTContext();
             auto diagID = diag::implicitly_final_cannot_be_open;
@@ -974,6 +964,11 @@ IsDynamicRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
     return true;
   }
 
+  // @_objcImplementation extension member implementations are implicitly
+  // dynamic.
+  if (decl->isObjCMemberImplementation())
+    return true;
+
   if (auto accessor = dyn_cast<AccessorDecl>(decl)) {
     // Runtime-replaceable accessors are dynamic when their storage declaration
     // is dynamic and they were explicitly defined or they are implicitly defined
@@ -1005,12 +1000,6 @@ IsDynamicRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
   if (isa<ExtensionDecl>(dc) && dc->getSelfClassDecl())
     return true;
 
-  // @objc declarations in @_objcImplementation extensions are implicitly
-  // dynamic.
-  if (auto ED = dyn_cast_or_null<ExtensionDecl>(dc->getAsDecl()))
-    if (ED->isObjCImplementation())
-      return true;
-
   // If any of the declarations overridden by this declaration are dynamic
   // or were imported from Objective-C, this declaration is dynamic.
   // Don't do this if the declaration is not exposed to Objective-C; that's

lib/Sema/TypeCheckDeclObjC.cpp

@@ -1881,26 +1881,6 @@ static ObjCSelector inferObjCName(ValueDecl *decl) {
   return *decl->getObjCRuntimeName(true);
 }
 
-static bool isObjCImplementation(AbstractFunctionDecl *method,
-                                 ObjCSelector methodName) {
-  auto ext = dyn_cast<ExtensionDecl>(method->getDeclContext());
-  if (!ext || !ext->isObjCImplementation())
-    return false;
-
-  auto contextInterface =
-      dyn_cast<IterableDeclContext>(ext->getImplementedObjCDecl());
-
-  for (auto otherMember : contextInterface->getMembers()) {
-    auto otherMethod = dyn_cast<AbstractFunctionDecl>(otherMember);
-    if (!otherMethod) continue;
-
-    if (otherMethod->getObjCSelector() == methodName)
-      return true;
-  }
-
-  return false;
-}
-
 /// Mark the given declaration as being Objective-C compatible (or
 /// not) as appropriate.
 ///
@@ -2062,8 +2042,7 @@ void markAsObjC(ValueDecl *D, ObjCReason reason,
 
     // Record the method in the type, if it's a member of one.
     if (auto tyDecl = D->getDeclContext()->getSelfNominalTypeDecl()) {
-      if (!isObjCImplementation(method, selector))
-        tyDecl->recordObjCMethod(method, selector);
+      tyDecl->recordObjCMethod(method, selector);
     }
 
     // Record the method in the source file.

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -1230,8 +1230,11 @@ static void checkObjCImplementationMemberAvoidsVTable(ValueDecl *VD) {
          !ED->getSelfClassDecl()->hasKnownSwiftImplementation() &&
          "@_objcImplementation on non-class or Swift class?");
 
-  if (VD->isSemanticallyFinal() || VD->isObjC()) {
-    assert(isa<DestructorDecl>(VD) || !VD->isObjC() || VD->isDynamic() &&
+  if (!VD->isObjCMemberImplementation())
+    return;
+
+  if (VD->isObjC()) {
+    assert(isa<DestructorDecl>(VD) || VD->isDynamic() &&
            "@objc decls in @_objcImplementations should be dynamic!");
     return;
   }

test/IRGen/objc_implementation.swift

@@ -75,14 +75,14 @@
 // CHECK: [[_METACLASS_DATA_SwiftSubclass]] = internal constant { i32, i32, i32, i32, i8*, i8*, i8*, i8*, i8*, i8*, i8* } { i32 129, i32 40, i32 40, i32 0, i8* null, i8* getelementptr inbounds ([41 x i8], [41 x i8]* @.str.40._TtC19objc_implementation13SwiftSubclass, i64 0, i64 0), i8* null, i8* null, i8* null, i8* null, i8* null }, section "__DATA, __objc_const", align 8
 
 // Class
-// CHECK: [[_INSTANCE_METHODS_SwiftSubclass:@[^, ]+]] = internal constant { i32, i32, [1 x { i8*, i8*, i8* }] } { i32 24, i32 1, [1 x { i8*, i8*, i8* }] [{ i8*, i8*, i8* } { i8* getelementptr inbounds ([12 x i8], [12 x i8]* [[selector_data_mainMethod_]], i64 0, i64 0), i8* getelementptr inbounds ([11 x i8], [11 x i8]* @".str.10.v20@0:8i16", i64 0, i64 0), i8* bitcast ({{.*}}* @"$s19objc_implementation13SwiftSubclassC10mainMethodyys5Int32VFTo{{(\.ptrauth)?}}" to i8*) }] }, section "__DATA, __objc_data", align 8
-// CHECK: [[_DATA_SwiftSubclass:@[^, ]+]] = internal constant { i32, i32, i32, i32, i8*, i8*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* } { i32 128, i32 24, i32 24, i32 0, i8* null, i8* getelementptr inbounds ([41 x i8], [41 x i8]* @.str.40._TtC19objc_implementation13SwiftSubclass, i64 0, i64 0), { i32, i32, [1 x { i8*, i8*, i8* }] }* [[_INSTANCE_METHODS_SwiftSubclass]], i8* null, i8* null, i8* null, i8* null }, section "__DATA, __objc_data", align 8
+// CHECK: [[_INSTANCE_METHODS_SwiftSubclass:@[^, ]+]] = internal constant { i32, i32, [2 x { i8*, i8*, i8* }] } { i32 24, i32 2, [2 x { i8*, i8*, i8* }] [{ i8*, i8*, i8* } { i8* getelementptr inbounds ([12 x i8], [12 x i8]* [[selector_data_mainMethod_]], i64 0, i64 0), i8* getelementptr inbounds ([11 x i8], [11 x i8]* @".str.10.v20@0:8i16", i64 0, i64 0), i8* bitcast ({{.*}}* @"$s19objc_implementation13SwiftSubclassC10mainMethodyys5Int32VFTo{{(\.ptrauth)?}}" to i8*) }, { i8*, i8*, i8* } { i8* getelementptr inbounds ([5 x i8], [5 x i8]* [[selector_data_init]], i64 0, i64 0), i8* getelementptr inbounds ([8 x i8], [8 x i8]* @".str.7.@16@0:8", i64 0, i64 0), i8* bitcast ({{.*}}* @"$s19objc_implementation13SwiftSubclassCACycfcTo{{(\.ptrauth)?}}" to i8*) }] }, section "__DATA, __objc_data", align 8
+// CHECK: [[_DATA_SwiftSubclass:@[^, ]+]] = internal constant { i32, i32, i32, i32, i8*, i8*, { i32, i32, [2 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* } { i32 128, i32 24, i32 24, i32 0, i8* null, i8* getelementptr inbounds ([41 x i8], [41 x i8]* @.str.40._TtC19objc_implementation13SwiftSubclass, i64 0, i64 0), { i32, i32, [2 x { i8*, i8*, i8* }] }* [[_INSTANCE_METHODS_SwiftSubclass]], i8* null, i8* null, i8* null, i8* null }, section "__DATA, __objc_data", align 8
 
 // Swift metadata
 // CHECK: @"$s19objc_implementationMXM" = linkonce_odr hidden constant <{ i32, i32, i32 }> <{ i32 0, i32 0, i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.19.objc_implementation to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32 }>, <{ i32, i32, i32 }>* @"$s19objc_implementationMXM", i32 0, i32 2) to i64)) to i32) }>, section "__TEXT,__const", align 4
 // CHECK: @"symbolic So9ImplClassC" = linkonce_odr hidden constant <{ [13 x i8], i8 }> <{ [13 x i8] c"So9ImplClassC", i8 0 }>, section "__TEXT,__swift5_typeref, regular", align 2
 // CHECK: @"$s19objc_implementation13SwiftSubclassCMn" = constant <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }> <{ i32 80, i32 trunc (i64 sub (i64 ptrtoint (<{ i32, i32, i32 }>* @"$s19objc_implementationMXM" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 1) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* @.str.13.SwiftSubclass to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (%swift.metadata_response (i64)* @"$s19objc_implementation13SwiftSubclassCMa" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 3) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ({ i32, i32, i16, i16, i32 }* @"$s19objc_implementation13SwiftSubclassCMF" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 4) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (<{ [13 x i8], i8 }>* @"symbolic So9ImplClassC" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn", i32 0, i32 5) to i64)) to i32), i32 2, i32 10, i32 0, i32 0, i32 10 }>, section "__TEXT,__const", align 4
-// CHECK: @"$s19objc_implementation13SwiftSubclassCMf" = internal global <{ void (%T19objc_implementation13SwiftSubclassC*)*, i8**, i64, %objc_class*, %swift.opaque*, %swift.opaque*, {{i64|%swift.opaque\*}}, i32, i32, i32, i16, i16, i32, i32, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>*, i8* }> <{ {{.*}}* @"$s19objc_implementation13SwiftSubclassCfD{{(\.ptrauth)?}}"{{( to void \(.*\)\*\))?}}, i8** @"$sBOWV", i64 ptrtoint (%objc_class* @"OBJC_METACLASS_$__TtC19objc_implementation13SwiftSubclass" to i64), %objc_class* bitcast (<{ i64, %objc_class*, %swift.opaque*, %swift.opaque*, { i32, i32, i32, i32, i8*, i8*, { i32, i32, [5 x { i8*, i8*, i8* }] }*, i8*, { i32, i32, [2 x { i64*, i8*, i8*, i32, i32 }] }*, i8*, { i32, i32, [1 x { i8*, i8* }] }* }* }>* @"OBJC_CLASS_$_ImplClass" to %objc_class*), %swift.opaque* @_objc_empty_cache, %swift.opaque* null, {{i64 add \(i64 ptrtoint|%swift.opaque\* bitcast \(i8\* getelementptr \(i8, i8\* bitcast}} ({ i32, i32, i32, i32, i8*, i8*, { i32, i32, [1 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* }* @_DATA__TtC19objc_implementation13SwiftSubclass to {{i64\), i64 1|i8\*\), i64 1\) to %swift.opaque\*}}), i32 0, i32 0, i32 24, i16 7, i16 0, i32 96, i32 16, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* {{(bitcast \(\{ i8\*, i32, i64, i64 \}\* )?}}@"$s19objc_implementation13SwiftSubclassCMn{{(\.ptrauth)?}}"{{( to <\{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 \}>\*\))?}}, i8* null }>, section "__DATA,__objc_data, regular", align 8
+// CHECK: @"$s19objc_implementation13SwiftSubclassCMf" = internal global <{ void (%T19objc_implementation13SwiftSubclassC*)*, i8**, i64, %objc_class*, %swift.opaque*, %swift.opaque*, {{i64|%swift.opaque\*}}, i32, i32, i32, i16, i16, i32, i32, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>*, i8* }> <{ {{.*}}* @"$s19objc_implementation13SwiftSubclassCfD{{(\.ptrauth)?}}"{{( to void \(.*\)\*\))?}}, i8** @"$sBOWV", i64 ptrtoint (%objc_class* @"OBJC_METACLASS_$__TtC19objc_implementation13SwiftSubclass" to i64), %objc_class* bitcast (<{ i64, %objc_class*, %swift.opaque*, %swift.opaque*, { i32, i32, i32, i32, i8*, i8*, { i32, i32, [5 x { i8*, i8*, i8* }] }*, i8*, { i32, i32, [2 x { i64*, i8*, i8*, i32, i32 }] }*, i8*, { i32, i32, [1 x { i8*, i8* }] }* }* }>* @"OBJC_CLASS_$_ImplClass" to %objc_class*), %swift.opaque* @_objc_empty_cache, %swift.opaque* null, {{i64 add \(i64 ptrtoint|%swift.opaque\* bitcast \(i8\* getelementptr \(i8, i8\* bitcast}} ({ i32, i32, i32, i32, i8*, i8*, { i32, i32, [2 x { i8*, i8*, i8* }] }*, i8*, i8*, i8*, i8* }* @_DATA__TtC19objc_implementation13SwiftSubclass to {{i64\), i64 1|i8\*\), i64 1\) to %swift.opaque\*}}), i32 0, i32 0, i32 24, i16 7, i16 0, i32 96, i32 16, <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* {{(bitcast \(\{ i8\*, i32, i64, i64 \}\* )?}}@"$s19objc_implementation13SwiftSubclassCMn{{(\.ptrauth)?}}"{{( to <\{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 \}>\*\))?}}, i8* null }>, section "__DATA,__objc_data, regular", align 8
 // CHECK: @"symbolic _____ 19objc_implementation13SwiftSubclassC" = linkonce_odr hidden constant <{ i8, i32, i8 }> <{ i8 1, i32 trunc (i64 sub (i64 ptrtoint (<{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>* @"$s19objc_implementation13SwiftSubclassCMn" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i8, i32, i8 }>, <{ i8, i32, i8 }>* @"symbolic _____ 19objc_implementation13SwiftSubclassC", i32 0, i32 1) to i64)) to i32), i8 0 }>, section "__TEXT,__swift5_typeref, regular", align 2
 // CHECK: @"$s19objc_implementation13SwiftSubclassCMF" = internal constant { i32, i32, i16, i16, i32 } { i32 trunc (i64 sub (i64 ptrtoint (<{ i8, i32, i8 }>* @"symbolic _____ 19objc_implementation13SwiftSubclassC" to i64), i64 ptrtoint ({ i32, i32, i16, i16, i32 }* @"$s19objc_implementation13SwiftSubclassCMF" to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (<{ [13 x i8], i8 }>* @"symbolic So9ImplClassC" to i64), i64 ptrtoint (i32* getelementptr inbounds ({ i32, i32, i16, i16, i32 }, { i32, i32, i16, i16, i32 }* @"$s19objc_implementation13SwiftSubclassCMF", i32 0, i32 1) to i64)) to i32), i16 7, i16 12, i32 0 }, section "__TEXT,__swift5_fieldmd, regular", align 4
 open class SwiftSubclass: ImplClass {

test/Interpreter/objc_implementation.swift

@@ -35,6 +35,7 @@ class LastWords {
       print("implProperty =", impl.implProperty)
       impl.implProperty = 42
       print("implProperty =", impl.implProperty)
+      print("description =", impl.description)
     }
 
     do {
@@ -43,7 +44,7 @@ class LastWords {
       print("implProperty =", swiftSub.implProperty)
       swiftSub.implProperty = 42
       print("implProperty =", swiftSub.implProperty)
-      
+
       print("otherProperty =", swiftSub.otherProperty)
       swiftSub.otherProperty = 13
       print("otherProperty =", swiftSub.otherProperty)
@@ -52,6 +53,10 @@ class LastWords {
   }
 
   @objc func someMethod() -> String { "ImplClass.someMethod()" }
+
+  open override var description: String {
+    "ImplClass(implProperty: \(implProperty), object: \(object))"
+  }
 }
 
 class SwiftSubclass: ImplClass {
@@ -70,6 +75,7 @@ ImplClass.runTests()
 // CHECK: someMethod = ImplClass.someMethod()
 // CHECK: implProperty = 0
 // CHECK: implProperty = 42
+// CHECK: description = ImplClass(implProperty: 42, object: main.LastWords)
 // CHECK: ImplClass It's better to burn out than to fade away.
 // CHECK: someMethod = SwiftSubclass.someMethod()
 // CHECK: implProperty = 0

test/decl/ext/Inputs/objc_implementation.h

@@ -1,4 +1,16 @@
-@interface ObjCClass
+@interface ObjCBaseClass
+
+
+// Need two initializers to reproduce certain conflict bugs.
+- (instancetype)initFromSuperclass:(int)param  __attribute__((objc_designated_initializer));
+- (instancetype)initFromSuperclass2:(int)param  __attribute__((objc_designated_initializer));
+
+- (void)superclassMethod:(int)param;
+@property (assign) int superclassProperty;
+
+@end
+
+@interface ObjCClass : ObjCBaseClass
 - (void)methodFromHeader1:(int)param;
 - (void)methodFromHeader2:(int)param;
 - (void)methodFromHeader3:(int)param;
@@ -40,6 +52,12 @@
 
 @end
 
+@interface ObjCSubclass : ObjCClass
+
+- (void)subclassMethodFromHeader1:(int)param;
+
+@end
+
 struct ObjCStruct {
   int foo;
 };

test/decl/ext/Inputs/objc_implementation_private.modulemap

@@ -0,0 +1,4 @@
+module objc_implementation_private {
+  header "objc_implementation.h"
+  export *
+}