Why do I get possible null-assignment warning on nullable types

Question

class Test {
}

//Main method
Test ccc = null;
string sss = null;

I am wondering why do I get a warning when I assign null to a string or to a class? Both are perfectly nullable. If I add the nullable ? annotation and say

Test? ccc = null;
string? sss = null;

then the warning will go away. But internally nothing has changed. What is the point of this?

Answer 1

What is the point of this?

The point is you can try to communicate, with the absence or presence of the ? mark, if the value of the reference type can be null, or not. And the C# compiler has static analysis that tries to assist you, so you do not run into a NullReferenceException as easily as you did in older versions of C#.

If you do not like it, it is possible to set nullable context to "disable". See link Nullable reference type for more.