Integration of null coalescing assignment and nullable reference type

[Logerfo]

Context

Currently, both null coalescing assignment and nullable reference types are available together in Visual Studio 19 Preview 1. However, I don't think they work together very well.

Code

#nullable enable
namespace A {
   public class C {
      public void M() {
         C? c = null;
         c ??= new C();
         c.M();
      }
   }
}

Expected behavior

The following code emits the same IL as the code above and has no warnings:

#nullable enable
namespace A {
   public class C {
      public void M() {
         C? c = null;
         if (c == null)
            c = new C();

         c.M();
      }
   }
}

For consistency reasons, the expected behavior for the stated code should also be zero warnings.

Atual behavior

Warning CS8602 Possible dereference of a null reference.

[Logerfo]

Found this listed on #22152, seems like it's already planned for preview 2.

[jaredpar]

Thanks for reporting. This is fixed now and covered sufficiently by NullCoalescingAssignment_UseInExpression