class Foo {
    Bar? b;
    Bar b2;
    Foo() {
        b.DoSomething(); //valid, but will cause exception
        b2.DoSomething(); //?
    }
}

String s = mayBeNull?.toString() ?: "null";

if (myObj)
{
    // in this scope, myObj is non-nullable, so can be used
}

if (SomeMethodReturningANullable() into anotherObj)
{
    // anotherObj is non-nullable, so can be used
}

string message = GetMessage() into m ? m : "No message available";

string message = GetMessage() or "No message available";

class SpecSharpExampleClass
{
    private string! _nonNullableExampleField;

    public SpecSharpExampleClass(string s)
        : _nonNullableExampleField(s)
    {

    }
}

b?->DoSomething();