Merge pull request swiftlang#67904 from beccadax/your-candidate-is-not-required

Handle inherited required inits in @objcImpl

Author: swift-ci

lib/Sema/TypeCheckDeclObjC.cpp

@@ -3507,6 +3507,15 @@ class ObjCImplementationChecker {
     for (auto &pair : unmatchedCandidates) {
       auto cand = pair.first;
 
+      // `isObjCMemberImplementation()` incorrectly returns true for required
+      // inits that are overrides because checking in that accessor would create
+      // a cycle between override computations and access control. Don't
+      // diagnose such candidates.
+      // FIXME: Refactor around this so these methods are never made candidates.
+      if (auto ctor = dyn_cast<ConstructorDecl>(cand))
+        if (ctor->isRequired() && !ctor->getOverriddenDecls().empty())
+          continue;
+
       diagnose(cand, diag::member_of_objc_implementation_not_objc_or_final,
                cand, cand->getDeclContext()->getSelfClassDecl());
 

test/decl/ext/Inputs/objc_implementation.h

@@ -157,6 +157,12 @@
 
 @end
 
+@interface ObjCImplSubclass : ObjCClass
+
+@end
+
+
+
 struct ObjCStruct {
   int foo;
 };

test/decl/ext/objc_implementation.swift

@@ -386,6 +386,13 @@ protocol EmptySwiftProto {}
   func nonPointerArgument(_: CInt!) {} // expected-error {{method cannot be implicitly @objc because the type of the parameter cannot be represented in Objective-C}}
 }
 
+@_objcImplementation extension ObjCImplSubclass {
+    @objc(initFromProtocol1:)
+    required public init?(fromProtocol1: CInt) {
+      // OK
+    }
+}
+
 @_objcImplementation extension ObjCClass {}
 // expected-error@-1 {{duplicate implementation of Objective-C class 'ObjCClass'}}