https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97632
Bug ID: 97632
Summary: unhelpful -Winit-list-lifetime warning for
default-initialized object in unevaluated context
Product: gcc
Version: 10.2.1
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
Target Milestone: ---
// { dg-options "-std=gnu++20" }
#include <initializer_list>
template<typename _Tp>
concept default_initializable =
requires
{
_Tp{};
(void) ::new _Tp;
};
static_assert( default_initializable<std::initializer_list<int>> );
GCC warns about this code:
warning: 'new' of 'initializer_list' does not extend the lifetime of the
underlying array [-Winit-list-lifetime]
I'm not sure this is very useful. Firstly, it's an unevaluated operand, so
there's no lifetime of anything here. Secondly, it's being constructed without
a new-initializer, so it's just an empty std::initializer_list, so there's no
underlying array.
