Sema: Report public conformances to non-publicly imported protocols

include/swift/AST/DiagnosticsSema.def

@@ -3648,7 +3648,8 @@ ERROR(decl_from_hidden_module,none,
       "cannot use %kind0 %select{here|as property wrapper here|"
       "as result builder here|"
       "in an extension with public or '@usableFromInline' members|"
-      "in an extension with conditional conformances}1; "
+      "in an extension with conditional conformances|"
+      "in a public or '@usableFromInline' conformance}1; "
       "%select{%2 has been imported as implementation-only|"
       "it is an SPI imported from %2|"
       "it is SPI|"
@@ -3662,7 +3663,8 @@ ERROR(typealias_desugars_to_type_from_hidden_module,none,
       "as property wrapper here|"
       "as result builder here|"
       "in an extension with public or '@usableFromInline' members|"
-      "in an extension with conditional conformances}3 "
+      "in an extension with conditional conformance|"
+      "in a public or '@usableFromInline' conformance}3 "
       "because %select{%4 has been imported as implementation-only|"
       "it is an SPI imported from %4|"
       "<<ERROR>>|"
@@ -3675,7 +3677,8 @@ ERROR(conformance_from_implementation_only_module,none,
       "cannot use conformance of %0 to %1 %select{here|as property wrapper here|"
       "as result builder here|"
       "in an extension with public or '@usableFromInline' members|"
-      "in an extension with conditional conformances}2; "
+      "in an extension with conditional conformances|"
+      "<<ERROR>>}2; "
       "%select{%3 has been imported as implementation-only|"
       "the conformance is declared as SPI in %3|"
       "the conformance is declared as SPI|"

lib/Sema/ResilienceDiagnostics.cpp

@@ -248,11 +248,22 @@ static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
   }
 
   // Access levels from imports are reported with the others access levels.
-  // Except for extensions, we report them here.
-  if (originKind == DisallowedOriginKind::NonPublicImport &&
-      reason != ExportabilityReason::ExtensionWithPublicMembers &&
-      reason != ExportabilityReason::ExtensionWithConditionalConformances)
-    return false;
+  // Except for extensions and protocol conformances, we report them here.
+  if (originKind == DisallowedOriginKind::NonPublicImport) {
+    bool reportHere = [&] {
+      switch (*reason) {
+        case ExportabilityReason::ExtensionWithPublicMembers:
+        case ExportabilityReason::ExtensionWithConditionalConformances:
+          return true;
+        case ExportabilityReason::Inheritance:
+          return isa<ProtocolDecl>(D);
+        default:
+          return false;
+      }
+    }();
+    if (!reportHere)
+      return false;
+  }
 
   if (ctx.LangOpts.EnableModuleApiImportRemarks &&
       import.has_value() && where.isExported() &&

lib/Sema/TypeCheckAccess.cpp

@@ -2259,7 +2259,7 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
 
     for (TypeLoc inherited : nominal->getInherited().getEntries()) {
       checkType(inherited.getType(), inherited.getTypeRepr(), nominal,
-                ExportabilityReason::General, flags);
+                ExportabilityReason::Inheritance, flags);
     }
   }
 
@@ -2361,7 +2361,7 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
     // must be exported.
     for (TypeLoc inherited : ED->getInherited().getEntries()) {
       checkType(inherited.getType(), inherited.getTypeRepr(), ED,
-                ExportabilityReason::General,
+                ExportabilityReason::Inheritance,
                 DeclAvailabilityFlag::AllowPotentiallyUnavailableProtocol);
     }
 

lib/Sema/TypeCheckAvailability.h

@@ -72,7 +72,8 @@ enum class ExportabilityReason : unsigned {
   PropertyWrapper,
   ResultBuilder,
   ExtensionWithPublicMembers,
-  ExtensionWithConditionalConformances
+  ExtensionWithConditionalConformances,
+  Inheritance
 };
 
 /// A description of the restrictions on what declarations can be referenced

test/SPI/implementation_only_spi_import_exposability.swift

@@ -32,8 +32,8 @@ public protocol IOIProtocol {}
 @_spi(B) public func leakSPIStruct(_ a: SPIStruct) -> SPIStruct { fatalError() } // expected-warning 2 {{cannot use struct 'SPIStruct' here; 'Lib' has been imported as implementation-only}}
 @_spi(B) public func leakIOIStruct(_ a: IOIStruct) -> IOIStruct { fatalError() } // expected-warning 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 struct PublicStruct : IOIProtocol, SPIProtocol { // expected-error {{cannot use protocol 'IOIProtocol' in a public or '@usableFromInline' conformance; 'Lib' has been imported as implementation-only}}
+// expected-error @-1 {{cannot use protocol 'SPIProtocol' in a public or '@usableFromInline' conformance; '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}}
 
@@ -49,8 +49,8 @@ public struct PublicStruct : IOIProtocol, SPIProtocol { // expected-error {{cann
 }
 
 @_spi(B)
-public struct LocalSPIStruct : IOIProtocol, SPIProtocol { // expected-warning {{cannot use protocol 'IOIProtocol' here; 'Lib' has been imported as implementation-only}}
-// expected-warning @-1 {{cannot use protocol 'SPIProtocol' here; 'Lib' has been imported as implementation-only}}
+public struct LocalSPIStruct : IOIProtocol, SPIProtocol { // expected-warning {{cannot use protocol 'IOIProtocol' in a public or '@usableFromInline' conformance; 'Lib' has been imported as implementation-only}}
+// expected-warning @-1 {{cannot use protocol 'SPIProtocol' in a public or '@usableFromInline' conformance; 'Lib' has been imported as implementation-only}}
 }
 
 #endif

test/SPI/local_spi_decls.swift

@@ -70,7 +70,7 @@ private protocol PrivateProtocol {} // expected-note {{type declared here}}
 
 @_spi(S) public class BadSubclass : InternalClass {} // expected-error{{class cannot be declared public because its superclass is internal}}
 @_spi(S) public class OkSPISubclass : SPIClass {} // OK
-public class BadPublicClass : SPIClass {} // expected-error {{cannot use class 'SPIClass' here; it is SPI}}
+public class BadPublicClass : SPIClass {} // expected-error {{cannot use class 'SPIClass' in a public or '@usableFromInline' conformance; it is SPI}}
 @_spi(S) public class BadSPIClass : PrivateClass {} // expected-error {{class cannot be declared public because its superclass is private}}
 
 @_spi(s) public func genFunc<T: PrivateProtocol>(_ t: T) {} // expected-error {{global function cannot be declared public because its generic parameter uses a private type}}

test/Sema/access-level-import-conforming-types.swift

@@ -0,0 +1,70 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -emit-module -o %t/NormalLibrary.swiftmodule \
+// RUN:  %S/Inputs/implementation-only-import-in-decls-public-helper.swift \
+// RUN:  -enable-library-evolution -swift-version 5
+
+// RUN: %target-swift-frontend -emit-module -o %t/BADLibrary.swiftmodule \
+// RUN:  %S/Inputs/implementation-only-import-in-decls-helper.swift -I %t \
+// RUN:  -enable-library-evolution -swift-version 5
+
+// RUN: %target-typecheck-verify-swift -I %t \
+// RUN:  -swift-version 5 -package-name pkg -enable-library-evolution
+// RUN: %target-typecheck-verify-swift -I %t \
+// RUN:  -swift-version 5 -package-name pkg
+
+internal import BADLibrary // expected-note 9 {{protocol 'BadProto' imported as 'internal' from 'BADLibrary' here}}
+// expected-note @-1 2 {{struct 'IntLike' imported as 'internal' from 'BADLibrary' here}}
+// expected-note @-2 2 {{class 'BadClass' imported as 'internal' from 'BADLibrary' here}}
+
+public protocol LocalProto {}
+
+public struct TestConformance: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+public struct TestConformanceComposition: LocalProto & BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+@usableFromInline struct TestConformanceUFI: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+public class TestConformanceClass: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+public enum TestConformanceEnum: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+public struct TestExtensionStruct {}
+extension TestExtensionStruct: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+package struct TestConformancePackage: BadProto {} // FIXME-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+package struct TestConformanceCompositionPackage: LocalProto & BadProto {} // FIXME-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+@usableFromInline struct TestConformanceUFIPackage: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+package class TestConformanceClassPackage: BadProto {} // FIXME-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+package enum TestConformanceEnumPackage: BADLibrary.BadProto {} // FIXME-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+package struct TestExtensionStructPackage {}
+extension TestExtensionStructPackage: BadProto {} // FIXME-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' was not imported publicly}}
+
+/// Other inheritance types are covered by the classic access-level check.
+
+public class TestSubclass: BadClass { // expected-error {{class cannot be declared public because its superclass is internal}}
+// expected-note @-1 {{class 'BadClass' is imported by this file as 'internal' from 'BADLibrary'}}
+}
+
+public enum TestRawType: IntLike { // expected-error {{enum cannot be declared public because its raw type uses an internal type}}
+// expected-note @-1 {{struct 'IntLike' is imported by this file as 'internal' from 'BADLibrary'}}
+  case x = 1
+}
+
+public protocol TestRefinedProto: BadProto { // expected-error {{public protocol cannot refine an internal protocol}}
+// expected-note @-1 {{protocol 'BadProto' is imported by this file as 'internal' from 'BADLibrary'}}
+}
+
+package class TestSubclassPackage: BadClass { // expected-error {{class cannot be declared package because its superclass is internal}}
+// expected-note @-1 {{class 'BadClass' is imported by this file as 'internal' from 'BADLibrary'}}
+}
+
+package enum TestRawTypePackage: IntLike { // expected-error {{enum cannot be declared package because its raw type uses an internal type}}
+// expected-note @-1 {{struct 'IntLike' is imported by this file as 'internal' from 'BADLibrary'}}
+  case x = 1
+}
+
+package protocol TestRefinedProtoPackage: BadProto { // expected-error {{package protocol cannot refine an internal protocol}}
+// expected-note @-1 {{protocol 'BadProto' is imported by this file as 'internal' from 'BADLibrary'}}
+}

test/Sema/access-level-import-typealias.swift

@@ -24,11 +24,10 @@ public typealias ClazzAlias = Clazz
 public import Aliases
 internal import Original // expected-note 2 {{class 'Clazz' imported as 'internal' from 'Original' here}}
 
-// expected-error@+1 {{'ClazzAlias' aliases 'Original.Clazz' and cannot be used here because 'Original' was not imported publicly}}
+// expected-error@+1 {{'ClazzAlias' aliases 'Original.Clazz' and cannot be used in a public or '@usableFromInline' conformance because 'Original' was not imported publicly}}
 public class InheritsFromClazzAlias: ClazzAlias {}
 
 @inlinable public func inlinableFunc() {
   // expected-error@+1 {{'ClazzAlias' aliases 'Original.Clazz' and cannot be used in an '@inlinable' function because 'Original' was not imported publicly}}
   _ = ClazzAlias.self
 }
-

test/Sema/implementation-only-import-in-decls.swift

@@ -11,15 +11,14 @@ import NormalLibrary
 @_implementationOnly import BADLibrary
 // expected-warning @-1 {{'@_implementationOnly' is deprecated, use 'internal import' instead}}
 
-public struct TestConformance: BadProto {} // expected-error {{cannot use protocol 'BadProto' here; 'BADLibrary' has been imported as implementation-only}}
+public struct TestConformance: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' has been imported as implementation-only}}
 
-@usableFromInline struct TestConformanceUFI: BadProto {} // expected-error {{cannot use protocol 'BadProto' here; 'BADLibrary' has been imported as implementation-only}}
+@usableFromInline struct TestConformanceUFI: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' has been imported as implementation-only}}
 
 struct TestConformanceOkay: BadProto {} // ok
 
-public class TestConformanceClass: BadProto {} // expected-error {{cannot use protocol 'BadProto' here; 'BADLibrary' has been imported as implementation-only}}
-public enum TestConformanceEnum: BadProto {} // expected-error {{cannot use protocol 'BadProto' here; 'BADLibrary' has been imported as implementation-only}}
-
+public class TestConformanceClass: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' has been imported as implementation-only}}
+public enum TestConformanceEnum: BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' has been imported as implementation-only}}
 
 public struct TestGenericParams<T: BadProto> {} // expected-error {{cannot use protocol 'BadProto' here; 'BADLibrary' has been imported as implementation-only}}
 
@@ -75,11 +74,11 @@ public protocol TestAssocTypeWhereClause {
   associatedtype Assoc: Collection where Assoc.Element: BadProto // expected-error {{cannot use protocol 'BadProto' here; 'BADLibrary' has been imported as implementation-only}}
 }
 
-public enum TestRawType: IntLike { // expected-error {{cannot use struct 'IntLike' here; 'BADLibrary' has been imported as implementation-only}}
+public enum TestRawType: IntLike { // expected-error {{cannot use struct 'IntLike' in a public or '@usableFromInline' conformance; 'BADLibrary' has been imported as implementation-only}}
   case x = 1
 }
 
-public class TestSubclass: BadClass { // expected-error {{cannot use class 'BadClass' here; 'BADLibrary' has been imported as implementation-only}}
+public class TestSubclass: BadClass { // expected-error {{cannot use class 'BadClass' in a public or '@usableFromInline' conformance; 'BADLibrary' has been imported as implementation-only}}
 }
 
 public typealias TestUnderlying = BadStruct // expected-error {{cannot use struct 'BadStruct' here; 'BADLibrary' has been imported as implementation-only}}
@@ -121,7 +120,7 @@ extension Array where Element == BadStruct {
   subscript(okay _: Int) -> Int { 0 } // okay
 }
 
-extension Int: @retroactive BadProto {} // expected-error {{cannot use protocol 'BadProto' here; 'BADLibrary' has been imported as implementation-only}}
+extension Int: @retroactive BadProto {} // expected-error {{cannot use protocol 'BadProto' in a public or '@usableFromInline' conformance; 'BADLibrary' has been imported as implementation-only}}
 struct TestExtensionConformanceOkay {}
 extension TestExtensionConformanceOkay: BadProto {} // okay
 

test/Sema/missing-import-typealias-swift6.swift

@@ -28,6 +28,6 @@ public typealias ClazzAlias = Clazz
 
 public import Aliases
 
-// expected-error@+1 {{'ClazzAlias' aliases 'Original.Clazz' and cannot be used here because 'Original' was not imported by this file}}
+// expected-error@+1 {{'ClazzAlias' aliases 'Original.Clazz' and cannot be used in a public or '@usableFromInline' conformance because 'Original' was not imported by this file}}
 public class InheritsFromClazzAlias: ClazzAlias {}
 

test/Sema/missing-import-typealias.swift

@@ -66,7 +66,7 @@ import Aliases
 
 // CHECK-NON-RESILIENT-NOT: was not imported by this file
 
-// expected-warning@+2 {{'ClazzAlias' aliases 'Original.Clazz' and cannot be used here because 'Original' was not imported by this file; this is an error in the Swift 6 language mode}}
+// expected-warning@+2 {{'ClazzAlias' aliases 'Original.Clazz' and cannot be used in a public or '@usableFromInline' conformance because 'Original' was not imported by this file; this is an error in the Swift 6 language mode}}
 // expected-note@+1 {{The missing import of module 'Original' will be added implicitly}}
 public class InheritsFromClazzAlias: ClazzAlias {}