Fix GetEnumerator when C# enumerator gets passed to native and back a…

…nd add tests

src/Authoring/WinRT.SourceGenerator/CsWinRTDiagnosticStrings.resx

@@ -113,7 +113,7 @@
     <value>Class is not marked partial</value>
   </data>
   <data name="ClassNotMarkedPartial_Text" xml:space="preserve">
-    <value>Class '{0}' implements WinRT interfaces but isn't marked partial.  Type should be marked partial for trimming and AOT compatibility if passed across the ABI.</value>
+    <value>Class '{0}' implements WinRT interfaces but isn't marked partial.  Type should be marked partial for trimming and AOT compatibility if passed across the WinRT ABI.</value>
   </data>
   <data name="DisjointNamespaceRule_Brief" xml:space="preserve">
     <value>Namespace is disjoint from main (winmd) namespace</value>
@@ -130,7 +130,7 @@
     <value>Project does not enable unsafe blocks</value>
   </data>
   <data name="EnableUnsafe_Text" xml:space="preserve">
-    <value>Type '{0}' implements generic WinRT interfaces which requires generated code using unsafe for trimming and AOT compatibility if passed across the ABI. Project needs to be updated with '&lt;AllowUnsafeBlocks&gt;true&lt;/AllowUnsafeBlocks&gt;'.</value>
+    <value>Type '{0}' implements generic WinRT interfaces which requires generated code using unsafe for trimming and AOT compatibility if passed across the WinRT ABI. Project needs to be updated with '&lt;AllowUnsafeBlocks&gt;true&lt;/AllowUnsafeBlocks&gt;'.</value>
   </data>
   <data name="GenericTypeRule_Brief" xml:space="preserve">
     <value>Class (or interface) is generic</value>

src/Tests/FunctionalTests/CCW/Program.cs

@@ -642,7 +642,7 @@ partial class Language
 {
     private readonly string[] _values = new string[4];
 
-    public string Name { get; } = "Language";
+    public string Name { get; init; } = "Language";
     public int Value { get; set; }
     public string this[int i]
     {

src/Tests/FunctionalTests/Collections/Program.cs

@@ -179,6 +179,46 @@
     return 101;
 }
 
+int sum = 0;
+var enumerator = instance.GetIteratorForCollection(expected);
+while (enumerator.MoveNext())
+{
+    sum += enumerator.Current;
+}
+
+if (sum != 3)
+{
+    return 101;
+}
+
+sum = 0;
+
+CustomIterableTest customIterableTest = new CustomIterableTest();
+foreach (var i in customIterableTest)
+{
+    sum += i;
+}
+
+if (sum != 6)
+{
+    return 101;
+}
+
+sum = 0;
+
+var arr = new int[] { 2, 4, 6 };
+CustomIterableTest customIterableTest2 = new CustomIterableTest(arr);
+foreach (var i in customIterableTest2)
+{
+    sum += i;
+}
+
+if (sum != 12)
+{
+    return 101;
+}
+
+
 return 100;
 
 static bool SequencesEqual<T>(IEnumerable<T> x, params IEnumerable<T>[] list) => list.All((y) => x.SequenceEqual(y));

src/Tests/TestComponentCSharp/Class.cpp

@@ -1503,6 +1503,11 @@ namespace winrt::TestComponentCSharp::implementation
         return winrt::single_threaded_vector(std::vector{ first, second });
     }
 
+    IIterator<int32_t> Class::GetIteratorForCollection(IIterable<int32_t> iterable)
+	{
+		return iterable.First();
+	}
+
     IBindableIterable Class::BindableIterableProperty()
     {
         return _bindableIterable;

src/Tests/TestComponentCSharp/Class.h

@@ -302,6 +302,8 @@ namespace winrt::TestComponentCSharp::implementation
         Windows::Foundation::Collections::IIterable<TestComponentCSharp::EnumValue> GetEnumIterable();
         Windows::Foundation::Collections::IIterable<TestComponentCSharp::CustomDisposableTest> GetClassIterable();
 
+        Windows::Foundation::Collections::IIterator<int32_t> GetIteratorForCollection(Windows::Foundation::Collections::IIterable<int32_t> iterable);
+
         Microsoft::UI::Xaml::Interop::IBindableIterable BindableIterableProperty();
         void BindableIterableProperty(Microsoft::UI::Xaml::Interop::IBindableIterable const& value);
         void RaiseBindableIterableChanged();

src/Tests/TestComponentCSharp/CustomIterableTest.cpp

@@ -0,0 +1,21 @@
+#include "pch.h"
+#include "CustomIterableTest.h"
+#include "CustomIterableTest.g.cpp"
+
+namespace winrt::TestComponentCSharp::implementation
+{
+    CustomIterableTest::CustomIterableTest()
+    {
+        _iterable = winrt::single_threaded_vector(std::vector{ 0, 2, 4 });
+    }
+
+    CustomIterableTest::CustomIterableTest(winrt::Windows::Foundation::Collections::IIterable<int32_t> const& iterable)
+    {
+		_iterable = iterable;
+    }
+
+    winrt::Windows::Foundation::Collections::IIterator<int32_t> CustomIterableTest::First()
+    {
+        return _iterable.First();
+    }
+}

src/Tests/TestComponentCSharp/CustomIterableTest.h

@@ -0,0 +1,22 @@
+#pragma once
+#include "CustomIterableTest.g.h"
+
+namespace winrt::TestComponentCSharp::implementation
+{
+    struct CustomIterableTest : CustomIterableTestT<CustomIterableTest>
+    {
+        CustomIterableTest();
+        CustomIterableTest(winrt::Windows::Foundation::Collections::IIterable<int32_t> const& iterable);
+
+        winrt::Windows::Foundation::Collections::IIterator<int32_t> First();
+
+        winrt::Windows::Foundation::Collections::IIterable<int32_t> _iterable;
+    };
+}
+
+namespace winrt::TestComponentCSharp::factory_implementation
+{
+    struct CustomIterableTest : CustomIterableTestT<CustomIterableTest, implementation::CustomIterableTest>
+    {
+    };
+}

src/Tests/TestComponentCSharp/TestComponentCSharp.idl

@@ -349,6 +349,8 @@ namespace TestComponentCSharp
         Windows.Foundation.Collections.IIterable<EnumValue> GetEnumIterable();
         Windows.Foundation.Collections.IIterable<CustomDisposableTest> GetClassIterable();
 
+        Windows.Foundation.Collections.IIterator<Int32> GetIteratorForCollection(Windows.Foundation.Collections.IIterable<Int32> iterable);
+
         // Bindable
         Microsoft.UI.Xaml.Interop.IBindableIterable BindableIterableProperty;
         void RaiseBindableIterableChanged();
@@ -518,6 +520,13 @@ namespace TestComponentCSharp
         CustomIteratorTest();
     }
 
+    [default_interface]
+    runtimeclass CustomIterableTest : Windows.Foundation.Collections.IIterable<Int32>
+    {
+		CustomIterableTest();
+        CustomIterableTest(Windows.Foundation.Collections.IIterable<Int32> iterable);
+    }
+
     // SupportedOSPlatform warning tests
     [contract(Windows.Foundation.UniversalApiContract, 10)]
     [attributeusage(target_all)]

src/Tests/TestComponentCSharp/TestComponentCSharp.vcxproj

@@ -84,6 +84,7 @@
     <ClInclude Include="ClassWithExplicitIUnknown.h" />
     <ClInclude Include="CustomExperimentClass.h" />
     <ClInclude Include="CustomEquals.h" />
+    <ClInclude Include="CustomIterableTest.h" />
     <ClInclude Include="ManualProjectionTestClasses.h" />
     <ClInclude Include="pch.h" />
     <ClInclude Include="Class.h">
@@ -105,6 +106,7 @@
     <ClCompile Include="ClassWithExplicitIUnknown.cpp" />
     <ClCompile Include="CustomExperimentClass.cpp" />
     <ClCompile Include="CustomEquals.cpp" />
+    <ClCompile Include="CustomIterableTest.cpp" />
     <ClCompile Include="pch.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>
     </ClCompile>

src/Tests/TestComponentCSharp/TestComponentCSharp.vcxproj.filters

@@ -23,6 +23,8 @@
     <ClCompile Include="CustomExperimentClass.cpp" />
     <ClCompile Include="WinRT.Class.cpp" />
     <ClCompile Include="ClassWithExplicitIUnknown.cpp" />
+    <ClCompile Include="NonUniqueClass.cpp" />
+    <ClCompile Include="CustomIterableTest.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="pch.h" />
@@ -39,6 +41,8 @@
     <ClInclude Include="CustomExperimentClass.h" />
     <ClInclude Include="WinRT.Class.h" />
     <ClInclude Include="ClassWithExplicitIUnknown.h" />
+    <ClInclude Include="NonUniqueClass.h" />
+    <ClInclude Include="CustomIterableTest.h" />
   </ItemGroup>
   <ItemGroup>
     <Midl Include="TestComponentCSharp.idl" />

src/WinRT.Runtime/Projections/IEnumerable.net5.cs

@@ -238,6 +238,11 @@ static IEnumerableMethods()
             {
                 return new global::ABI.System.Collections.Generic.FromAbiEnumerator<T>(ienumeratorImpl);
             }
+            else if (first is global::ABI.System.Collections.Generic.ToAbiEnumeratorAdapter<T> toAbiAdapter)
+            {
+                // Unwrap to get the C# enumerator if it was originally one.
+                return toAbiAdapter.m_enumerator;
+            }
 
             throw new InvalidOperationException("Unexpected type for enumerator");
         }
@@ -939,7 +944,7 @@ public ComWrappers.ComInterfaceEntry[] GetExposedInterfaces()
     // we can't make them AOT friendly due to we can't reference them.
     public sealed class ToAbiEnumeratorAdapter<T> : global::System.Collections.Generic.IEnumerator<T>, global::System.Collections.IEnumerator
     {
-        private readonly global::System.Collections.Generic.IEnumerator<T> m_enumerator;
+        internal readonly global::System.Collections.Generic.IEnumerator<T> m_enumerator;
 
         internal ToAbiEnumeratorAdapter(global::System.Collections.Generic.IEnumerator<T> enumerator) => m_enumerator = enumerator;