Second Draft: Placement New Expression

[Paul Backus]

On Wednesday, 20 November 2024 at 01:49:23 UTC, Walter Bright 
wrote:
> On 11/19/2024 11:02 AM, Paul Backus wrote:
>> Using a typed lvalue instead of void[] is just asking to shoot 
>> yourself in the foot, especially when it comes to 
>> const/immutable:
>
> This (and some other reasons) is why placement new will not be 
> allowed in @safe code. The compiler will never be able to 
> properly vet the provenance of the memory being overwritten by 
> placement new.

I agree that it can't be @safe, void[] or not. But my impression 
is that even in @system code, D generally tries to guide the 
programmer away from error-prone constructs (for example, 
requiring an explicit `= void` to leave a variable 
uninitialized). Using a void[] instead of a typed lvalue would be 
consistent with that approach.