Move Constructor Syntax

[Arafel]

On 16.10.24 15:06, Timon Gehr wrote:

> With Walter's current preferred design, a new dummy object is created in the old memory location. I.e., it has to be valid, but it does not have to contain any data.

[...]

> A key difference between `this(S s)` and `=this(ref S)` is that the 
> latter elides the destructor by default, while for the former, the least 
> surprising semantics would be that it calls the destructor of the source 
> at the end of the scope by default. There would then need to be an 
> additional feature to elide the destructor call with manual syntax.

Let me go back to my original example, slightly modified to make my 
point more clear:


```d
struct S {
     int i;
     this(C)(C c) if (is(C : int)) {
         this.i = c;
     }

     alias i this;
}

void main() {
     S s1, s2, s3;
     int i = 1;
     s1 = S(1);
     s2 = S(i);
     s3 = S(s2); // This was most certainly not intended as a move 
constructor.
     assert(s2.i == 1);
     assert(s3.i == 1);
}
```

Would this code still be guaranteed to pass the asserts if the signature 
for move constructors becomes `this (S s)` (Walter's proposal)? I mean 
based on assurances by the language itself, not on what the compiler 
might decide to do (or not) with s2.