https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104706
Bug ID: 104706
Summary: make_unique cannot create struct of size of 0 due to
default_delete's static_assert failure
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nickhuang99 at hotmail dot com
Target Milestone: ---
See code in compiler explorer: https://www.godbolt.org/z/cb8973Ys1
struct of size of 0 does have its usage and it is supported by GNU C
(https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html). However, make_unique
makes it impossible to create such an unique_ptr because its default_delete
requires "A" must have non-zero size.
struct A{
alignas(int[0]) int ptr[0];
};
void test(){
unique_ptr<A> ptr=make_unique<A>();
}
error: static assertion failed: can't delete pointer to incomplete type
83 | static_assert(sizeof(_Tp)>0,
| ~~~~~~~~~~~^~
I am not arguing that static_assert is reasonable. My point is that
"make_shared" can actually deal this properly. i.e.
shared_ptr ptr=make_shared<A>();
gives no error at all.
