Hi Ungureanu,

On 2026-06-16T15:49:20+0300, Ungureanu Radu wrote:
> On Tue Jun 16, 2026 at 3:13 PM EEST, Alejandro Colomar wrote:
> > Hi Ungureanu,
> >
> > On 2026-06-16T13:08:18+0300, Ungureanu Radu via Std-Proposals wrote:
> >> You bring up a good point, but I think that this can be solved by making
> >> it only for named parameters only. For example:
> >>
> >> void f(X x{5}); // OK
> >> void f(X {5}); // Not allowed by the proposed syntax
> >>
> >> This would avoid changing the current disambiguation rules for something
> >> like:
> >>
> >> X g(X{5});
> >>
> >> which would continue to be parsed as it is today. Otherwise, the
> >> disambiguation would have to get even more complex and could possibly
> >> break existing code.
> >
> > I don't know if this would be ambiguous to a compiler or not. But it
> > will most certainly be ambiguous to a human.
> >
> >
> > Have a lovely day!
> > Alex
>
> Hi Alex,
>
> I am not so sure about this being ambiguous to readers. Let's take an
> ordinary declaration for example:
>
> int x{5};
>
> Here, the braces are usually understood as initializing x. Similarly,
>
> void f(int x{5});
>
> can naturally be read as "x has initializer {5}".
>
> While a parameter declaration is not an object definition, parameters
> still have initialization semantics. When an argument is supplied, the
> parameter is initialized with that argument. When it's not supplied,
> then the parameter is initialized from the default expression.
>
> This proposal simply expresses that initialization more directly,
> without requiring the type to be repeated in the default argument
> expression
>
> Can you elaborate on the ambiguity you have in mind? I may be missing a
> point of confusion here.

T f(T x{5});
T g(T{5});

These two are too similar to have a different meaning, IMO.


Cheers,
Alex

>
> Best regards,
> Radu
>

-- 
<https://www.alejandro-colomar.es>