opAssign() still accepted for classes???

[KennyTM~]

On Apr 30, 11 00:14, Alexander wrote:
> On 29.04.2011 17:05, Steven Schveighoffer wrote:
>
>> x = y is equivalent to x.opAssign(y).  So x is null, you are dereferencing a null pointer.
>
>    Second thought... Since compiler *knows* that the pointer is null at this point, shouldn't it produce a warning at least?
>
> /Alexander

That requires data flow analysis. For example, how could the compiler 
knows the 'x' below is 'null'?

     K x;
     if (veryComplexCondition(y))
        x = new K;
     x = 4.0;   // <----

See http://www.digitalmars.com/d/2.0/faq.html#nan.

(That said, I see no problem treating this as a warning (which is 
outside of the D spec) if a variable is provable 'null'.)