Re: Non-null objects, the Null Object pattern, and T.init

[Timon Gehr]

On 01/19/2014 01:03 PM, Michel Fortin wrote:

Actually, 'A?' would implicitly convert to 'A' where the compiler can
prove control flow prevents its value from being null.

I think the type should be upgraded. i.e.:

So you can
dereference it in a branch that checked for null:

     class A { int i; void foo(); }
     void bar(A a); // non-nullable parameter

     void test(A? a, A? a2)
     {
         a.i++; // error, 'a' might be null
         a.foo(); // error, 'a' might be null
         bar(a); // error, 'a' might be null

         if (a)
         {

               static assert(is(typeof(a)==A));

             a.i++; // valid [...]
             a.foo(); // valid [...]
             bar(a); // valid [...]
         }
     }