https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126120
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2026-07-06
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to winapiadmin from comment #0)
> Created attachment 64943 [details]
> The reproduce code, compiled with C++17
Strictly speaking, there are no Constraints in the C++17 standard:
Requires: Construction of d and a deleter of type D initialized with
std::move(d) shall not throw exceptions. The expression d(p) shall have
well-defined behavior and shall not throw exceptions.
That was replaced with Constraints: for C++20, but we do intend to implement
the Constraints: all the way back to C++11.
We do constrain the std::shared_ptr constructors:
template<typename _Yp, typename _Deleter,
typename = _Constructible<_Yp*, _Deleter>>
shared_ptr(_Yp* __p, _Deleter __d)
: __shared_ptr<_Tp>(__p, std::move(__d)) { }
But that _Constructible check only checks if the std::__shared_ptr base class
is constructible from those arguments, and the base constructor is *not*
constrained on the deleter being invocable.
So we need to either adjust the constrains on the derived class, or add the
correct constraints on the base class.
