[6.1] AST: Only apply MemberImportVisibility to lookups from the main module

lib/AST/NameLookup.cpp

@@ -2330,22 +2330,27 @@ ObjCCategoryNameMap ClassDecl::getObjCCategoryNameMap() {
                            ObjCCategoryNameMap());
 }
 
-static bool missingImportForMemberDecl(const DeclContext *dc, ValueDecl *decl) {
-  // Only require explicit imports for members when MemberImportVisibility is
-  // enabled.
-  auto &ctx = dc->getASTContext();
+/// Determines whether MemberImportVisiblity should be enforced for lookups in
+/// the given context.
+static bool shouldRequireImportsInContext(const DeclContext *lookupContext) {
+  auto &ctx = lookupContext->getASTContext();
   if (!ctx.LangOpts.hasFeature(Feature::MemberImportVisibility))
     return false;
 
-  return !dc->isDeclImported(decl);
+  // Code outside of the main module (which is often synthesized) isn't subject
+  // to MemberImportVisibility rules.
+  if (lookupContext->getParentModule() != ctx.MainModule)
+    return false;
+
+  return true;
 }
 
 /// Determine whether the given declaration is an acceptable lookup
 /// result when searching from the given DeclContext.
-static bool isAcceptableLookupResult(const DeclContext *dc,
-                                     NLOptions options,
+static bool isAcceptableLookupResult(const DeclContext *dc, NLOptions options,
                                      ValueDecl *decl,
-                                     bool onlyCompleteObjectInits) {
+                                     bool onlyCompleteObjectInits,
+                                     bool requireImport) {
   // Filter out designated initializers, if requested.
   if (onlyCompleteObjectInits) {
     if (auto ctor = dyn_cast<ConstructorDecl>(decl)) {
@@ -2373,10 +2378,9 @@ static bool isAcceptableLookupResult(const DeclContext *dc,
 
   // Check that there is some import in the originating context that makes this
   // decl visible.
-  if (!(options & NL_IgnoreMissingImports)) {
-    if (missingImportForMemberDecl(dc, decl))
+  if (requireImport && !(options & NL_IgnoreMissingImports))
+    if (!dc->isDeclImported(decl))
       return false;
-  }
 
   return true;
 }
@@ -2593,6 +2597,9 @@ QualifiedLookupRequest::evaluate(Evaluator &eval, const DeclContext *DC,
   // Whether we only want to return complete object initializers.
   bool onlyCompleteObjectInits = false;
 
+  // Whether to enforce MemberImportVisibility import restrictions.
+  bool requireImport = shouldRequireImportsInContext(DC);
+
   // Visit all of the nominal types we know about, discovering any others
   // we need along the way.
   bool wantProtocolMembers = (options & NL_ProtocolMembers);
@@ -2625,7 +2632,8 @@ QualifiedLookupRequest::evaluate(Evaluator &eval, const DeclContext *DC,
       if ((options & NL_OnlyMacros) && !isa<MacroDecl>(decl))
         continue;
 
-      if (isAcceptableLookupResult(DC, options, decl, onlyCompleteObjectInits))
+      if (isAcceptableLookupResult(DC, options, decl, onlyCompleteObjectInits,
+                                   requireImport))
         decls.push_back(decl);
     }
 
@@ -2762,6 +2770,9 @@ AnyObjectLookupRequest::evaluate(Evaluator &evaluator, const DeclContext *dc,
                                              member.getFullName(), allDecls);
   }
 
+  /// Whether to enforce MemberImportVisibility import restrictions.
+  bool requireImport = shouldRequireImportsInContext(dc);
+
   // For each declaration whose context is not something we've
   // already visited above, add it to the list of declarations.
   llvm::SmallPtrSet<ValueDecl *, 4> knownDecls;
@@ -2794,7 +2805,8 @@ AnyObjectLookupRequest::evaluate(Evaluator &evaluator, const DeclContext *dc,
     // result, add it to the list.
     if (knownDecls.insert(decl).second &&
         isAcceptableLookupResult(dc, options, decl,
-                                 /*onlyCompleteObjectInits=*/false))
+                                 /*onlyCompleteObjectInits=*/false,
+                                 requireImport))
       decls.push_back(decl);
   }
 

validation-test/ClangImporter/cfobject-conformances.swift

@@ -0,0 +1,23 @@
+// RUN: %target-swift-frontend -emit-sil %s -verify
+// RUN: %target-swift-frontend -emit-sil %s -enable-upcoming-feature MemberImportVisibility -verify
+
+// REQUIRES: VENDOR=apple
+// REQUIRES: swift_feature_MemberImportVisibility
+
+import CoreFoundation
+
+public func takesHashable<T: Hashable>(_ t: T) {}
+
+public func takesCFObjects(
+  _ string: CFString,
+  _ number: CFNumber,
+  _ date: CFDate,
+  _ data: CFData,
+  _ set: CFSet,
+) {
+  takesHashable(string)
+  takesHashable(number)
+  takesHashable(date)
+  takesHashable(data)
+  takesHashable(set)
+}