Second Draft: Placement New Expression

[Paul Backus]

On Tuesday, 19 November 2024 at 05:05:57 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> This still includes typed expressions, which I have some 
> concerns about.
>
> We should not be condoning uninitialized memory as having a 
> type. It can only cause problems for people. If we stick to 
> ``void[]`` as the input, we can limit the source to ``@system`` 
> code only.
>
> No double-init bugs please.

+1

Using a typed lvalue instead of void[] is just asking to shoot 
yourself in the foot, especially when it comes to const/immutable:

     struct S { int i; char c; }

     void main()
     {
         S dest;
         immutable(S)* p = new immutable(S)(dest)(123, 'A');
         assert(p.i == 123 && p.c == 'A');
         dest.i = 0; // oops, undefined behavior!
     }