Merge pull request #83387 from swiftlang/private-fileid-not-retroactive

[cxx-interop] Do not consider extensions blessed by SWIFT_PRIVATE_FILEID to be retroactive

Author: j-hui

lib/AST/ProtocolConformance.cpp

@@ -28,10 +28,12 @@
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/PackConformance.h"
+#include "swift/AST/Type.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/Statistic.h"
+#include "swift/ClangImporter/ClangImporter.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/SaveAndRestore.h"
@@ -248,6 +250,18 @@ bool ProtocolConformance::isRetroactive() const {
     if (isSameRetroactiveContext(extensionModule, conformingTypeModule)) {
       return false;
     }
+
+    auto *useSF = getDeclContext()->getOutermostParentSourceFile();
+    auto blessesSF = [&](auto &blessed) {
+      auto blessedFileID = SourceFile::FileIDStr::parse(blessed.first);
+      return blessedFileID && blessedFileID->matches(useSF);
+    };
+    auto *clangDecl = dyn_cast_or_null<clang::CXXRecordDecl>(
+        conformingTypeDecl->getClangDecl());
+    if (clangDecl &&
+        llvm::any_of(importer::getPrivateFileIDAttrs(clangDecl), blessesSF)) {
+      return false;
+    }
   }
 
   return true;

test/Interop/Cxx/class/access/private-fileid-conformance.swift

@@ -0,0 +1,53 @@
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -typecheck -verify -I %t/Cxx/include %t/PrivateFile.swift -cxx-interoperability-mode=default -module-name Module
+// RUN: %target-swift-frontend -typecheck -verify -I %t/Cxx/include %t/HasRetroactive.swift -cxx-interoperability-mode=default -module-name Module
+// RUN: %target-swift-frontend -typecheck -verify -I %t/Cxx/include %t/NoRetroactive.swift -cxx-interoperability-mode=default -module-name Module
+
+//--- Cxx/include/module.modulemap
+module CxxModule {
+    requires cplusplus
+    header "cxx-header.h"
+}
+
+//--- Cxx/include/cxx-header.h
+#pragma once
+
+#define SWIFT_PRIVATE_FILEID(_fileID) \
+  __attribute__((swift_attr("private_fileid:" _fileID)))
+
+class SWIFT_PRIVATE_FILEID("Module/PrivateFile.swift") Foo { void privateMethod(void) const {} };
+
+//--- PrivateFile.swift
+import CxxModule
+
+extension Foo : ExpressibleByIntegerLiteral {
+    public typealias IntegerLiteralType = Int
+    public init(integerLiteral: Self.IntegerLiteralType) {
+        self.init()
+        self.privateMethod()
+    }
+}
+
+//--- HasRetroactive.swift
+import CxxModule
+
+extension Foo : @retroactive ExpressibleByIntegerLiteral {
+    public typealias IntegerLiteralType = Int
+    public init(integerLiteral: Self.IntegerLiteralType) {
+        self.init()
+        self.privateMethod() // expected-error {{'privateMethod' is inaccessible due to 'private' protection level}}
+    }
+}
+
+//--- NoRetroactive.swift
+import CxxModule
+
+// expected-warning@+2 {{extension declares a conformance of imported type 'Foo' to imported protocol 'ExpressibleByIntegerLiteral'}}
+// expected-note@+1 {{add '@retroactive' to silence this warning}}
+extension Foo : ExpressibleByIntegerLiteral {
+    public typealias IntegerLiteralType = Int
+    public init(integerLiteral: Self.IntegerLiteralType) {
+        self.init()
+        self.privateMethod() // expected-error {{'privateMethod' is inaccessible due to 'private' protection level}}
+    }
+}