[Sema] Fix leak of implementation-only imported types in SPI signatures

rdar://63193289

Author: xymus

lib/Sema/TypeCheckAccess.cpp

@@ -1483,11 +1483,14 @@ class UsableFromInlineChecker : public AccessControlCheckerBase,
   }
 };
 
+// Diagnose public APIs exposing types that are either imported as
+// implementation-only or declared as SPI.
 class ExportabilityChecker : public DeclVisitor<ExportabilityChecker> {
   class Diagnoser;
 
   void checkTypeImpl(
       Type type, const TypeRepr *typeRepr, const SourceFile &SF,
+      const Decl *context,
       const Diagnoser &diagnoser) {
     // Don't bother checking errors.
     if (type && type->hasError())
@@ -1500,14 +1503,15 @@ class ExportabilityChecker : public DeclVisitor<ExportabilityChecker> {
     if (typeRepr) {
       const_cast<TypeRepr *>(typeRepr)->walk(TypeReprIdentFinder(
           [&](const ComponentIdentTypeRepr *component) {
-        ModuleDecl *M = component->getBoundDecl()->getModuleContext();
-        if (!SF.isImportedImplementationOnly(M) &&
-            !SF.isImportedAsSPI(component->getBoundDecl()))
-          return true;
-
-        diagnoser.diagnoseType(component->getBoundDecl(), component,
-                               SF.isImportedImplementationOnly(M));
-        foundAnyIssues = true;
+        TypeDecl *typeDecl = component->getBoundDecl();
+        ModuleDecl *M = typeDecl->getModuleContext();
+        bool isImplementationOnly = SF.isImportedImplementationOnly(M);
+        if (isImplementationOnly ||
+            (SF.isImportedAsSPI(typeDecl) && !context->isSPI())) {
+          diagnoser.diagnoseType(typeDecl, component, isImplementationOnly);
+          foundAnyIssues = true;
+        }
+
         // We still continue even in the diagnostic case to report multiple
         // violations.
         return true;
@@ -1525,19 +1529,19 @@ class ExportabilityChecker : public DeclVisitor<ExportabilityChecker> {
 
     class ProblematicTypeFinder : public TypeDeclFinder {
       const SourceFile &SF;
+      const Decl *context;
       const Diagnoser &diagnoser;
     public:
-      ProblematicTypeFinder(const SourceFile &SF, const Diagnoser &diagnoser)
-        : SF(SF), diagnoser(diagnoser) {}
+      ProblematicTypeFinder(const SourceFile &SF, const Decl *context, const Diagnoser &diagnoser)
+        : SF(SF), context(context), diagnoser(diagnoser) {}
 
       void visitTypeDecl(const TypeDecl *typeDecl) {
         ModuleDecl *M = typeDecl->getModuleContext();
-        if (!SF.isImportedImplementationOnly(M) &&
-            !SF.isImportedAsSPI(typeDecl))
-          return;
-
-        diagnoser.diagnoseType(typeDecl, /*typeRepr*/nullptr,
-                               SF.isImportedImplementationOnly(M));
+        bool isImplementationOnly = SF.isImportedImplementationOnly(M);
+        if (isImplementationOnly ||
+            (SF.isImportedAsSPI(typeDecl) && !context->isSPI()))
+          diagnoser.diagnoseType(typeDecl, /*typeRepr*/nullptr,
+                                 isImplementationOnly);
       }
 
       void visitSubstitutionMap(SubstitutionMap subs) {
@@ -1597,15 +1601,15 @@ class ExportabilityChecker : public DeclVisitor<ExportabilityChecker> {
       }
     };
 
-    type.walk(ProblematicTypeFinder(SF, diagnoser));
+    type.walk(ProblematicTypeFinder(SF, context, diagnoser));
   }
 
   void checkType(
       Type type, const TypeRepr *typeRepr, const Decl *context,
       const Diagnoser &diagnoser) {
     auto *SF = context->getDeclContext()->getParentSourceFile();
     assert(SF && "checking a non-source declaration?");
-    return checkTypeImpl(type, typeRepr, *SF, diagnoser);
+    return checkTypeImpl(type, typeRepr, *SF, context, diagnoser);
   }
 
   void checkType(
@@ -1702,7 +1706,7 @@ class ExportabilityChecker : public DeclVisitor<ExportabilityChecker> {
     AccessScope accessScope =
         VD->getFormalAccessScope(nullptr,
                                  /*treatUsableFromInlineAsPublic*/true);
-    if (accessScope.isPublic() && !accessScope.isSPI())
+    if (accessScope.isPublic())
       return false;
 
     // Is this a stored property in a non-resilient struct or class?

test/SPI/implementation_only_spi_import_exposability.swift

@@ -0,0 +1,46 @@
+/// @_implementationOnly imported decls (SPI or not) should not be exposed in SPI.
+
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -DLIB %s -module-name Lib -emit-module-path %t/Lib.swiftmodule
+// RUN: %target-typecheck-verify-swift -DCLIENT -I %t
+
+#if LIB
+
+@_spi(A) public func spiFunc() {}
+
+@_spi(A) public struct SPIStruct {
+  public init() {}
+}
+
+@_spi(A) public protocol SPIProtocol {}
+
+public func ioiFunc() {}
+
+public struct IOIStruct {
+  public init() {}
+}
+
+public protocol IOIProtocol {}
+
+#elseif CLIENT
+
+@_spi(A) @_implementationOnly import Lib
+
+@_spi(B) public func leakSPIStruct(_ a: SPIStruct) -> SPIStruct { fatalError() } // expected-error 2 {{cannot use struct 'SPIStruct' here; 'Lib' has been imported as implementation-only}}
+@_spi(B) public func leakIOIStruct(_ a: IOIStruct) -> IOIStruct { fatalError() } // expected-error 2 {{cannot use struct 'IOIStruct' here; 'Lib' has been imported as implementation-only}}
+
+public struct PublicStruct : IOIProtocol, SPIProtocol { // expected-error {{cannot use protocol 'IOIProtocol' here; 'Lib' has been imported as implementation-only}}
+// expected-error @-1 {{cannot use protocol 'SPIProtocol' here; 'Lib' has been imported as implementation-only}}
+  public var spiStruct = SPIStruct() // expected-error {{cannot use struct 'SPIStruct' here; 'Lib' has been imported as implementation-only}}
+  public var ioiStruct = IOIStruct() // expected-error {{cannot use struct 'IOIStruct' here; 'Lib' has been imported as implementation-only}}
+
+  @inlinable
+  public func publicInlinable() {
+    spiFunc() // expected-error {{global function 'spiFunc()' is '@_spi' and cannot be referenced from an '@inlinable' function}}
+    ioiFunc() // expected-error {{global function 'ioiFunc()' cannot be used in an '@inlinable' function because 'Lib' was imported implementation-only}}
+    let s = SPIStruct() // expected-error {{struct 'SPIStruct' is '@_spi' and cannot be referenced from an '@inlinable' function}}
+    let i = IOIStruct() // expected-error {{struct 'IOIStruct' cannot be used in an '@inlinable' function because 'Lib' was imported implementation-only}}
+  }
+}
+
+#endif