[Bug c++/95349] Using std::launder(p) produces unexpected behavior where (p) produces expected behavior

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95349

--- Comment #51 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #48)
> (In reply to Christopher Nerz from comment #47)
> > But shouldn't both give the same value?
> 
> I'm not sure what the standard says to this.  Does std::launder(...)
> sanitize earlier "undefined behavior"?  For example failing to initialize
> an object?

No.

The example appears to be trying to use std::launder as std::start_lifetime_as,
but they're not the same.