Blazor: suspicious CS8601 on nullable delegate/Func/Action component parameters

[airwedge1]

Is there an existing issue for this?

• [X] I have searched the existing issues

Describe the bug

Re-opening https://github.com/dotnet/aspnetcore/issues/22488 as this is quite annoying.

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

7.0.402.

Anything else?

No response

[mkArtakMSFT]

Thanks for raising this. Which .NET SDK version are you seeing this issues with?

[ghost]

Hi @airwedge1. We have added the "Needs: Author Feedback" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[ghost]

Thank you for filing this issue. In order for us to investigate this issue, please provide a minimal repro project that illustrates the problem without unnecessary code. Please share with us in a public GitHub repo because we cannot open ZIP attachments, and don't include any confidential content.

[airwedge1]

7.0.402. This happens on every .net core version since blazor was created.

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[ImrePyhvelMerit]

Hey, this is obviously a bug, and annoying at that.

The minimal repro wasa already given in #22488, I can repro this on .Net core 7.0.11:

Repro: For example, take Component1.razor:

<h3>Component 1</h3>

@Content

@code {
    [Parameter]
    public RenderFragment? Content { get; set; }

    [Parameter]
    public Func<int, int>? MyFunc { get; set; }

    [Parameter]
    public (int, int)? MyTuple { get; set; }

}

Which is used into Component2.razor:

<h3>Component 2</h3>

<Component1 Content="ContentNullable"  /* Warning CS8601 */
            MyFunc="MyFuncNullable"    /* Warning CS8601 */
            MyTuple="MyTupleNullable"> /* Ok */
</Component1>

@code {
    public RenderFragment? ContentNullable { get; set; }

    public Func<int, int>? MyFuncNullable { get; set; }

    public (int, int)? MyTupleNullable { get; set; }
}

And you get the CS8601 warning on Content and MyFunc parameters assignment.

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s). If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues. To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s). If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues. To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[1cue-jrupp]

We're also facing this issue with several components that accept nullable Parameters for a good reason. This is quite annoying troughout all .NET Versions including the newest .NET 8 release.