https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116769
Bug ID: 116769
Summary: Instantiation of defaulted default constructor with
non default constructible NDSMIs
Product: gcc
Version: 14.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dangelog at gmail dot com
Target Milestone: ---
Hi,
Consider this testcase:
#include <type_traits>
struct NDC { NDC(int); };
template <typename T>
struct Wrap
{
Wrap() = default;
Wrap(const T &t) : t(t) {}
T t = T();
};
static_assert(!std::is_default_constructible_v<Wrap<NDC>>);
GCC accepts this, while Clang / MSVC reject:
https://gcc.godbolt.org/z/njh6Tvj19
Is this supposed to be ill-formed instead? Wrap's default constructor is going
to be defined (and NOT deleted, https://eel.is/c++draft/class.default.ctor#2.5
should not apply here), and that should cause the =T() initialization for the
member to fail to compile.
