https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82647
Bug ID: 82647
Summary: std::tuple_size_v is missing from <array> and
<utility>
Product: gcc
Version: 7.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: bitbug1985 at icloud dot com
Target Milestone: ---
x.cpp:
#include <array>
int
main()
{
std::array<int, 3> arr;
auto size = std::tuple_size_v<decltype(arr)>;
}
% g++ --version
g++ (MacPorts gcc7 7.2.0_0) 7.2.0
% g++ -std=c++17 -o x x.cpp
x.cpp: In function 'int main()':
x.cpp:7:22: error: 'tuple_size_v' is not a member of 'std'
auto size = std::tuple_size_v<decltype(arr)>;
^~~~~~~~~~~~
x.cpp:7:22: note: suggested alternative: 'tuple_size'
auto size = std::tuple_size_v<decltype(arr)>;
^~~~~~~~~~~~
tuple_size
x.cpp:7:35: error: expected primary-expression before 'decltype'
auto size = std::tuple_size_v<decltype(arr)>;
^~~~~~~~
I get the same error if I replace std::array with std::pair. If I additionally
include <tuple>, which should be unnecessary, this compiles. For what it's
worth, it compiles as-is in clang++.
