Possible compiler bug - no warning when calling extension method w/o await

[TahirAhmadov]

#nullable enable
using System;
using System.Threading.Tasks;

public class C {
    ActionAsync? _action;
    public async Task M() {
        await Task.Delay(100);
        this._action?.InvokeAsync(); // no warning here (this caused a bug for me)
        if(this._action != null)
            this._action(); // however, this one does get a warning (as expected)
    }
}

public delegate Task ActionAsync();

public static partial class _Delegate_Extensions
{
	public static async Task InvokeAsync(this ActionAsync? This)
	{
		if (This != null)
		{
			foreach (ActionAsync d in This.GetInvocationList())
			{
				await d();
			}
		}
	}
}

VS does offer to add an await on that this._action?.InvokeAsync(); line (but no warning).

PS. Never mind - I figured it out: I mistakenly added a ? after this._action to make it null-propagating, which converted the return of InvokeAsync to Task?, hence no warning.
Hopefully I don't need this InvokeAsync with nullable this parameter anymore when we get "await if Task not null" feature.

[HaloFour]

Looks like it's the result of the null-propagation operator, removing that will emit the warning. But an await there would throw if _action is null, so it's not exactly a good pattern in general, at least without await? or the like.

[TahirAhmadov]

I figured it out myself literally a minute after posting it. Yes we really need the await?.

[TahirAhmadov]

BTW, thanks for your response anyway.