Nullable reference type as cascading type argument produces errors at design time

[jjonescz]

using Microsoft.AspNetCore.Components;

namespace Test;

[CascadingTypeParameter(nameof(TRow))]
public class Parent<TRow>: ComponentBase
{
    [Parameter]
    public RenderFragment<TRow>? ChildContent { get; set; }
}

public class Child<TRow> : ComponentBase
{
    [Parameter]
    public RenderFragment<TRow>? ChildContent { get; set; }
}

<Parent TRow="string?">
    <Child Context="childContext">@childContext.Length</Child>
</Parent>

In design time build, there's an error:

error CS8639: The typeof operator cannot be used on a nullable reference type

Because this code is generated:

        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
        {
            __o = typeof(
#nullable restore
#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
              string?

#line default
#line hidden
#nullable disable
            );
            __builder.AddAttribute(-1, "ChildContent", (global::Microsoft.AspNetCore.Components.RenderFragment<string?>)((context) => (__builder2) => {
                var __typeInference_CreateChild_0 = global::__Blazor.Test.TestComponent.TypeInference.CreateChild_0(__builder2, -1, default(string?)!, -1, (childContext) => (__builder3) => {
#nullable restore
#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
                             __o = childContext.Length;

#line default
#line hidden
#nullable disable
                }
                );
#nullable restore
#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
__o = typeof(global::Test.Child<>);

#line default
#line hidden
#nullable disable
            }
            ));
#nullable restore
#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
__o = typeof(global::Test.Parent<>);

#line default
#line hidden
#nullable disable
        }