#nullable enable

public delegate void Del<T>(T t = default);

public class C<T>
{
    public void M0(T t) { }

    // Behavior for member methods, for comparison
    public void M1(T t = default)
    {
        M0(t); // warning CS8604: Possible null reference argument
    }
    
    public void M2()
    {
        Del<T> del = t => M0(t); // expected warning, but didn't get one
        Del<T> del1 = t => { t = default; M0(t); }; // warning CS8604: Possible null reference argument
    }
}