Move Constructor Syntax

[RazvanN]

On Tuesday, 15 October 2024 at 16:54:50 UTC, Manu wrote:

> Okay, but I've asked people to stop talking about move 
> constructors... it seems to have poisoned everyone's brains 
> with irrelevant focus. We're talking about function arguments 
> in general, we don't need more bizarre edge cases, especially 
> not so deep in the foundations.
>
> Run your thought experiment with:
>   void f(T);
>   void f(ref T)
>
> The constructor isn't special... don't special-case the 
> constructor.
>

I think that Timon did an excellent job at explaining why we are 
focusing on constructors. Also, as he noted, those are 
implementation details - modifying
the code to fix the current infinite recursion depends largely on 
how we treat
overload resolution with respect to copy/move constructors. I 
tried to express
the same idea, but Timon did it better. So, from my perspective, 
which is an
implementation perspective, it's a matter if we are willing to 
special case the
move/copy constructor base case in the overload resolution 
mechanism or not.

> "Trade offs"? Do you have anything in mind?
> I would be surprised if there are any 'trade-offs'; any change 
> here will
> probably be fixing language holes or broken edge cases... what 
> actually
> stands to break? What good-stuff™ could we possibly be 
> 'trading' away?

I was talking about implementation trade-offs, not user facing 
trade-offs.
I.E. we are modifying the overload resolution algorithm by adding 
a special (or base) case. It could be that this is desirable in 
this case, I do not know, but
I suspect that this is the reason why Walter is on the "let's add 
new syntax for this" wagon (but I might be wrong).

As for the `this(typeof(this))` being a move constructor - I 
completely agree with everything you've said this far. I am not 
counter-arguing anything that you said, I'm just presenting what 
the situation with respect to the compiler implementation is.

RazvanN