https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94831
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #0)
> In r277342 I changed std::_Construct for P0784R7, "More constexpr
> containers" and the non-void return type means this no longer compiles:
>
> #include <vector>
> std::vector<float[2]> v(1);
>
> This was never valid in C++98, and in C++11 to C++17 it's undefined (because
> the pseudo-destructor call in allocator_traits<std::allocator<T>>::destroy
> is ill-formed for arrays). But for libstdc++ it happened to compile, because
> we elide the calls to trivial destructors.
We should consider making this change in stage 1, to stop silently accepting
that non-standard code in strict mode:
--- a/libstdc++-v3/include/bits/alloc_traits.h
+++ b/libstdc++-v3/include/bits/alloc_traits.h
@@ -734,6 +734,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Destroy(_ForwardIterator __first, _ForwardIterator __last,
allocator<_Tp>&)
{
+#if __cplusplus >= 201103L && defined __STRICT_ANSI__
+ static_assert(!is_array<_Tp>::value,
+ "arrays are not Erasable from containers using std::allocator");
+#endif
_Destroy(__first, __last);
}
