Package name is only printed in private swiftinterface. This causes

ambiguity during lookup when there are multiple public or inlinalbe
package decls in public interfaces. This PR adds a package name to
public swiftinterface and lets typecheck look up the package name
to narrow down the scope of access to package decls from an external
module.

Resolves rdar://117699160

Author: elsh

include/swift/AST/Module.h

@@ -210,6 +210,7 @@ class PackageUnit: public DeclContext {
   /// Equality check via package name instead of pointer comparison.
   /// Returns false if the name is empty.
   bool isSamePackageAs(PackageUnit *other) {
+    if (!other) return false;
     return !(getName().empty()) && getName() == other->getName();
   }
 };

lib/AST/Decl.cpp

@@ -4294,13 +4294,8 @@ static bool checkAccessUsingAccessScopes(const DeclContext *useDC,
       VD, access, useDC,
       /*treatUsableFromInlineAsPublic*/ includeInlineable);
   if (accessScope.getDeclContext() == useDC) return true;
-  if (!AccessScope(useDC).isChildOf(accessScope)) {
-    // Grant access if this VD is an inlinable package decl referenced by
-    // another module in an interface file.
-    if (VD->skipAccessCheckIfInterface(useDC, access, accessScope))
-      return true;
-    return false;
-  }
+  if (!AccessScope(useDC).isChildOf(accessScope)) return false;
+
   // useDC is null only when caller wants to skip non-public type checks.
   if (!useDC) return true;
 
@@ -4426,14 +4421,6 @@ static bool checkAccess(const DeclContext *useDC, const ValueDecl *VD,
     return useSF && useSF->hasTestableOrPrivateImport(access, sourceModule);
   }
   case AccessLevel::Package: {
-    auto srcFile = sourceDC->getParentSourceFile();
-
-    // srcFile could be null if VD decl is from an imported .swiftmodule
-    if (srcFile && srcFile->Kind == SourceFileKind::Interface) {
-      // If source file is interface, package decls must be usableFromInline or
-      // inlinable, and are accessed only within the defining module so return true
-      return true;
-    }
     auto srcPkg = sourceDC->getPackageContext(/*lookupIfNotCurrent*/ true);
     auto usePkg = useDC->getPackageContext(/*lookupIfNotCurrent*/ true);
     return srcPkg && usePkg && usePkg->isSamePackageAs(srcPkg);

lib/Frontend/ModuleInterfaceSupport.cpp

@@ -92,6 +92,10 @@ static void printToolVersionAndFlagsComment(raw_ostream &out,
       }
     }
   }
+  if (!M->getPackageName().empty()) {
+    StringRef pkgName = M->getPackageName().str();
+    out << " -package-name " << pkgName;
+  }
   out << "\n";
 
   if (!Opts.IgnorableFlags.empty()) {

lib/Sema/TypeCheckProtocol.cpp

@@ -4435,10 +4435,6 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
           requiredAccessScope.requiredAccessForDiagnostics();
         auto proto = conformance->getProtocol();
         auto protoAccessScope = proto->getFormalAccessScope(DC);
-        // Skip diagnostics of a witness of a package protocol that is inlinalbe
-        // referenced in an interface file.
-        if (proto->skipAccessCheckIfInterface(DC, requiredAccess, protoAccessScope))
-          return;
         bool protoForcesAccess =
           requiredAccessScope.hasEqualDeclContextWith(protoAccessScope);
         auto diagKind = protoForcesAccess

test/Sema/accessibility_package_inline_interface.swift

@@ -9,8 +9,8 @@
 // RUN: %target-swift-typecheck-module-from-interface(%t/Utils.swiftinterface) -I%t
 
 // RUN: %FileCheck %s -check-prefix CHECK-UTILS < %t/Utils.swiftinterface
-// CHECK-UTILS-NOT: -package-name myLib
 // CHECK-UTILS: -module-name Utils
+// CHECK-UTILS: -package-name myLib
 // CHECK-UTILS: @usableFromInline
 // CHECK-UTILS: package class PackageKlassProto {
 // CHECK-UTILS:   @usableFromInline

test/Sema/accessibility_package_interface.swift

@@ -12,13 +12,13 @@
 // RUN: %target-swift-typecheck-module-from-interface(%t/Utils.swiftinterface) -I %t
 // RUN: %FileCheck %s --check-prefix=CHECK-PUBLIC-UTILS < %t/Utils.swiftinterface
 
-// CHECK-PUBLIC-UTILS-NOT: -package-name swift-utils.log
 // CHECK-PUBLIC-UTILS-NOT: package func packageFunc()
 // CHECK-PUBLIC-UTILS-NOT: package protocol PackageProto
 // CHECK-PUBLIC-UTILS-NOT: var pkgVar
 // CHECK-PUBLIC-UTILS-NOT: package class PackageKlass
 // CHECK-PUBLIC-UTILS-NOT: package var pkgVar
 // CHECK-PUBLIC-UTILS: -module-name Utils
+// CHECK-PUBLIC-UTILS: -package-name swift-utils.log
 // CHECK-PUBLIC-UTILS: public func publicFunc()
 // CHECK-PUBLIC-UTILS: @usableFromInline
 // CHECK-PUBLIC-UTILS: package func ufiPackageFunc()
@@ -39,7 +39,7 @@
 // CHECK-PRIVATE-UTILS-NOT: package class PackageKlass
 // CHECK-PRIVATE-UTILS-NOT: package var pkgVar
 // CHECK-PRIVATE-UTILS: -module-name Utils
-// CHECK-PRIVATE-UTILS: swift-module-flags-ignorable-private: -package-name swift-utils.log
+// CHECK-PRIVATE-UTILS: -package-name swift-utils.log
 // CHECK-PRIVATE-UTILS: public func publicFunc()
 // CHECK-PRIVATE-UTILS: @usableFromInline
 // CHECK-PRIVATE-UTILS: package func ufiPackageFunc()
@@ -64,7 +64,7 @@
 
 // RUN: %target-swift-typecheck-module-from-interface(%t/Client.swiftinterface) -I %t -verify
 // RUN: %FileCheck %s --check-prefix=CHECK-PUBLIC-CLIENT < %t/Client.swiftinterface
-// CHECK-PUBLIC-CLIENT-NOT: -package-name swift-utils.log
+// CHECK-PUBLIC-CLIENT: -package-name swift-utils.log
 // CHECK-PUBLIC-CLIENT: @inlinable public func clientFunc()
 // CHECK-PUBLIC-CLIENT: publicFunc()
 // CHECK-PUBLIC-CLIENT: ufiPackageFunc()

test/Serialization/load_package_module.swift

@@ -19,11 +19,11 @@
 // RUN: %target-swift-typecheck-module-from-interface(%t/LibInterface.swiftinterface) -I %t
 // RUN: %FileCheck %s --check-prefix=CHECK-PUBLIC < %t/LibInterface.swiftinterface
 // CHECK-PUBLIC: -module-name LibInterface
-// CHECK-PUBLIC-NOT: -package-name
+// CHECK-PUBLIC: -package-name
 
 // RUN: %target-swift-typecheck-module-from-interface(%t/LibInterface.private.swiftinterface) -module-name LibInterface -I %t
 // RUN: %FileCheck %s --check-prefix=CHECK-PRIVATE < %t/LibInterface.private.swiftinterface
-// CHECK-PRIVATE: swift-module-flags-ignorable-private: -package-name libPkg
+// CHECK-PRIVATE: -package-name libPkg
 
 // RUN: not %target-swift-frontend -typecheck %t/ClientLoadInterface.swift -package-name otherPkg -I %t 2> %t/resultX.output
 // RUN: %FileCheck %s -check-prefix CHECK-X < %t/resultX.output

test/Serialization/module_package_name.swift

@@ -11,12 +11,12 @@
 // RUN: %target-swift-typecheck-module-from-interface(%t/Logging.swiftinterface) -I %t
 // RUN: %FileCheck %s --check-prefix=CHECK-PUBLIC < %t/Logging.swiftinterface
 // CHECK-PUBLIC: -module-name Logging
-// CHECK-PUBLIC-NOT: -package-name
+// CHECK-PUBLIC: -package-name
 
 // RUN: %target-swift-typecheck-module-from-interface(%t/Logging.private.swiftinterface) -module-name Logging -I %t
 // RUN: %FileCheck %s --check-prefix=CHECK-PRIVATE < %t/Logging.private.swiftinterface
 // CHECK-PRIVATE: -module-name Logging
-// CHECK-PRIVATE: swift-module-flags-ignorable-private: -package-name MyLoggingPkg
+// CHECK-PRIVATE: -package-name MyLoggingPkg
 
 //--- File.swift
 public func log(level: Int) {}