Memory safe in D

[Nick Treleaven]

On Saturday, 30 March 2024 at 03:00:32 UTC, Walter Bright wrote:
> On 3/22/2024 3:51 AM, Nick Treleaven wrote:
>> I think this is workable without DFA, the compiler just tracks 
>> when a variable is initialized. There is never a state where a 
>> variable may be both initialized and not initialized
>
> ```
> A a = null;
> if (i)
>     a = new A();
> // a is both initialized and not initialized
> ```

There `a` is always initialized. It's a nullable type. If you 
remove the `= null` and make `a` a non-nullable type, you would 
get an error for the `if` statement because it initializes `a` in 
its branch, and there is no `else` branch which is required to 
also initialize `a`.

> Now throw in loops and goto's, and DFA is needed. Compiler 
> optimizers use DFA because it works and ad-hoc techniques do 
> not.

This does not need DFA, correct?