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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/114479] [14 Regression] std::is_array_v<int[0]> changed
 from false to true in GCC 14
Date: Sun, 31 Mar 2024 10:05:42 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114479

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
[dcl.array] says that for T[N] the value "N specifies the array bound, i.e.,
the
number of elements in the array; N shall be greater than zero."

So T[0] is not a valid array type. And std::is_array<T[0]> has never been t=
rue
for any traditional implementation based on partial specialization of class
templates, only when switching to an intrinsic __is_array that fails to
accurately give the same behaviour as the std::is_array trait.

Since the purpose of the __is_array intrinsic is to optimize the std::is_ar=
ray
trait, it should have the same behaviour. For the optimization to change the
behaviour of the trait seems like the tail wagging the dog.=