https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79702
Bug ID: 79702
Summary: AX_CXX_COMPILE_STDCXX([17]) does not work with
GCC=7.0.1
Product: gcc
Version: 7.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: kreckel at ginac dot de
Target Milestone: ---
This program is reduced from the C++17 conftest produced by the macro from
https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html:
#include <utility>
struct S
{
int x1 : 2;
volatile double y1;
};
S f3()
{
return {};
}
const auto [ x3, y3 ] = f3();
It fails to compile with g++ 7.0.1 20170205 on x86_64-pc-linux-gnu:
$ g++ -std=c++17 -c conftest.cpp
conftest.cpp:14:12: error: 'std::tuple_size<const S>::value' is not an integral
constant expression
const auto [ x3, y3 ] = f3();
^~~~~~~~~~
The error has something to do with <utility>, as it goes away if I comment out
the #include directive.
