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

[Timon Gehr]

On 01/20/2014 01:44 AM, Michel Fortin wrote:
>
> That's one way to do it. Note that this means you can't assign null to
> 'a' inside the 'if' branch.  ...

Such an assignment could downgrade the type again. An alternative would 
be to not use flow analysis at all and require eg:

A? a=foo();
if(A b=a){
     // use b of type 'A' here
}

A solution that sometimes allows A? to be dereferenced will likely have 
issues with eg. IFTI.