Is there a way to tell a compiler that argument's property is not null if method returns

[maxkoshevoi]

I have code like this:

bool CheckProperty(MyType instance) => instance.A?.B?.C != null;

void Main()
{
    if (CheckProperty(instance))
    {
        Console.WriteLine(instance.A.B.C); // <- Warning here
    }
}

Is there a way to annotate CheckProperty method so that Console.WriteLine(instance.A.B.C); line wouldn't show a warning?

[jnm2]

No, not currently. The list of possible annotations is at https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/attributes/nullable-analysis.

[Joe4evr]

You can't use the attributes to inform null analysis beyond the scope of the current type.
The best you'll get here today is

if (instance.A?.B?.C is {} c)
{
     Console.WriteLine(c);
}