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NativeAOT fails with GVM runtime lookup that involves an unboxing stub #129696
Description
Found in #128702 (comment)
Repro:
public class GenericVirtualMethodTests
{
public static void Main()
{
RuntimeLookupDelegate();
}
public static void RuntimeLookupDelegate()
{
RuntimeLookupDelegateGenericVirtual.Test<string>();
}
}
internal class RuntimeLookupDelegateGenericVirtual
{
internal static void Test<T>()
{
IBase foo = new DerivedStruct();
Delegate d = foo.Foo<List<T>>();
MethodInfo expected = typeof(DerivedStruct).GetMethod(nameof(DerivedStruct.Foo))!.MakeGenericMethod(typeof(List<T>));
Assert.Equal(expected, d.Method);
}
}
internal interface IBase
{
Delegate Foo<U>();
}
internal struct DerivedStruct : IBase
{
public Delegate Foo<U>()
{
return Foo<U>;
}
}Publish with NativeAOT and run:
Unhandled exception. System.ArgumentException: An item with the same key has already been added.
at Internal.Runtime.TypeLoader.TypeLoaderEnvironment.RegisterDynamicGenericTypesAndMethods(TypeLoaderEnvironment.DynamicGenericsRegistrationData) + 0x382
at Internal.Runtime.TypeLoader.TypeBuilder.RegisterGenericTypesAndMethods() + 0x150
at Internal.Runtime.TypeLoader.TypeBuilder.FinishTypeAndMethodBuilding() + 0x372
at Internal.Runtime.TypeLoader.TypeBuilder.TryBuildGenericMethod(InstantiatedMethod, IntPtr&) + 0x35
at Internal.Runtime.TypeLoader.TypeLoaderEnvironment.TryGetGenericVirtualMethodPointer(InstantiatedMethod, IntPtr&, IntPtr&) + 0x24d
at Internal.Runtime.TypeLoader.TypeLoaderEnvironment.ResolveGenericVirtualMethodTarget(RuntimeTypeHandle, RuntimeMethodHandle) + 0xae
at System.Runtime.TypeLoaderExports.CacheMiss(IntPtr, IntPtr, RuntimeObjectFactory, Object) + 0x3c
at System.Runtime.TypeLoaderExports.GVMLookupForSlotSlow(Object, RuntimeMethodHandle) + 0x68
at RuntimeLookupDelegateGenericVirtual.Test[T]() + 0x2e
at GenericVirtualMethodTests.Main() + 0x10
Activity
dotnet-policy-service commentedon Jun 22, 2026
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[-]NativeAOT fails with GVM lookup that has an unboxing stub[/-][+]NativeAOT fails with GVM runtime lookup that involves an unboxing stub[/+]MihuBot commentedon Jun 22, 2026
I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):
Internal.Runtime.TypeLoader.TypeLoaderEnvironment.RegisterDynamicGenericTypesAndMethodswhen calling some GVMs #118072Fix building unboxing and real generic method targets at the same time (
Fix building unboxing and real generic method targets at the same time (