static_cast<Derived*>(&arg)->open();
 
and
 
static_cast<Derived&>(arg).open();

work.

 

 

You used the mix

 

static_cast<Derived&>(arg)->open();


 

-----Ursprüngliche Nachricht-----
Von: Frederick Virchanza Gotham via Std-Proposals <std-proposals@lists.isocpp.org>
Gesendet: Di 27.02.2024 22:07
Betreff: Re: [std-proposals] dynamic_cast<void*>(void*)
An: std-proposals@lists.isocpp.org;
CC: Frederick Virchanza Gotham <cauldwell.thomas@gmail.com>;
On Tue, Feb 27, 2024 at 3:58 PM Thiago Macieira wrote:
>
> Never mind, then. I've never used dynamic_cast in that scenario precisely
> because static_cast works, so I didn't actually remember it was already
> forbidden.


We're downcasting here -- not upcasting. Replacing dynamic_cast with
static_cast won't work here.
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