Don't emit default ctor for non activatable types

src/Authoring/WinRT.SourceGenerator/WinRTTypeWriter.cs

@@ -1932,12 +1932,25 @@ void AddComponentType(INamedTypeSymbol type, Action visitTypeDeclaration = null)
 
  bool isInterface = type.TypeKind == TypeKind.Interface;
  bool hasConstructor = false;
+ bool hasAtLeastOneNonPublicConstructor = false;
  bool hasDefaultConstructor = false;
  foreach (var member in type.GetMembers())
  {
  if (!IsPublic(member) || typeDeclaration.CustomMappedSymbols.Contains(member))
  {
  Logger.Log(member.Kind + " member skipped " + member.Name);
+
+ // We want to track whether a given public class has at least one non-public constructor.
+ // In this case, the class is still exposed to WinRT, but it's not activatable. This is
+ // different than a class with no explicit constructor, where we do want to generate that
+ // in the .winmd, and make the class activatable. But we want to avoid always emitting a
+ // default constructor for classes that only have non-public ones.
+ if (type.TypeKind == TypeKind.Class &&
+ member is IMethodSymbol { MethodKind: MethodKind.Constructor })
+ {
+ hasAtLeastOneNonPublicConstructor = true;
+ }
+
  continue;
  }
 
@@ -1988,8 +2001,8 @@ void AddComponentType(INamedTypeSymbol type, Action visitTypeDeclaration = null)
  CheckAndMarkSymbolForAttributes(member);
  }
 
- // implicit constructor if none defined
- if (!hasConstructor && type.TypeKind == TypeKind.Class && !type.IsStatic)
+ // Implicit constructor if none defined, but only if the type doesn't already have some non-public constructor
+ if (!hasConstructor && !hasAtLeastOneNonPublicConstructor && type.TypeKind == TypeKind.Class && !type.IsStatic)
  {
  string constructorMethodName = ".ctor";
  var methodDefinitionHandle = AddMethodDefinition(

src/Tests/AuthoringConsumptionTest/AuthoringConsumptionTest.exe.manifest

@@ -82,9 +82,21 @@
  name="AuthoringTest.CustomXamlMetadataProvider"
  threadingModel="both"
  xmlns="urn:schemas-microsoft-com:winrt.v1" />
-  <activatableClass
+ <activatableClass
  name="AuthoringTest.CustomInterfaceGuidClass"
  threadingModel="both"
  xmlns="urn:schemas-microsoft-com:winrt.v1" />
+ <activatableClass
+ name="AuthoringTest.NonActivatableType"
+ threadingModel="both"
+ xmlns="urn:schemas-microsoft-com:winrt.v1" />
+ <activatableClass
+ name="AuthoringTest.NonActivatableFactory"
+ threadingModel="both"
+ xmlns="urn:schemas-microsoft-com:winrt.v1" />
+ <activatableClass
+ name="AuthoringTest.TypeOnlyActivatableViaItsOwnFactory"
+ threadingModel="both"
+ xmlns="urn:schemas-microsoft-com:winrt.v1" />
  </file>
 </assembly>

src/Tests/AuthoringConsumptionTest/test.cpp

@@ -735,4 +735,14 @@ TEST(AuthoringTest, CustomInterfaceGuid)
  check_hresult(customInterfaceClassUnknown->QueryInterface(customInterfaceIid, reinterpret_cast<void**>(winrt::put_abi(customInterface))));
 
  EXPECT_EQ(customInterface.HelloWorld(), L"Hello World!");
+}
+
+TEST(AuthoringTest, NonActivatableFactory)
+{
+ EXPECT_EQ(NonActivatableFactory::Create().GetText(), L"Test123");
+}
+
+TEST(AuthoringTest, TypeOnlyActivatableViaItsOwnFactory)
+{
+ EXPECT_EQ(TypeOnlyActivatableViaItsOwnFactory::Create().GetText(), L"Hello!");
 }

src/Tests/AuthoringTest/Program.cs

@@ -1865,6 +1865,50 @@ public sealed class CustomInterfaceGuidClass : ICustomInterfaceGuid
  {
  public string HelloWorld() => "Hello World!";
  }
+
+ public sealed class NonActivatableType
+ {
+ private readonly string _text;
+
+ // This should not be referenced by the generated activation factory
+ internal NonActivatableType(string text)
+ {
+ _text = text;
+ }
+
+ public string GetText()
+ {
+ return _text;
+ }
+ }
+
+ public static class NonActivatableFactory
+ {
+ public static NonActivatableType Create()
+ {
+ return new("Test123");
+ }
+ }
+
+ public sealed class TypeOnlyActivatableViaItsOwnFactory
+ {
+ private readonly string _text;
+
+ private TypeOnlyActivatableViaItsOwnFactory(string text)
+ {
+ _text = text;
+ }
+
+ public static TypeOnlyActivatableViaItsOwnFactory Create()
+ {
+ return new("Hello!");
+ }
+
+ public string GetText()
+ {
+ return _text;
+ }
+ }
 }
 
 namespace ABI.AuthoringTest