Hi,
Boost.PolyCollection tests have started to cycle and I found VS 2017 aka
MSVC 14.1 fails
at test_algorithm.cpp:
http://tinyurl.com/yb4zdkys
whereas this test compiles and runs OK with VS 2015 aka MSVC 4.0
(_MSC_FULL_VER = 190023026). I've distilled down the problem to this
test case:
#include <algorithm>
#include <utility>
template
struct all_of
{
template
auto operator()(Args&&... args)const->
decltype(std::all_of(std::forward<Args>(args)...))
{
return std::all_of(std::forward<Args>(args)...);
}
};
int main()
{
int x;
all_of<> alg;
alg(&x,&x,[](int){return true;});
}
which works fine with GCC and VS 2015 but fails in webcompiler.cloudapp.net
with
Compiled with /EHsc /nologo /W4 /c
main.cpp
main.cpp(9): error C3546: '...': there are no parameter packs
available to expand
main.cpp(18): note: see reference to class template instantiation
'all_of<>' being compiled
(_MSC_FULL_VER = 191125331, which I think is VS 2017.3 or something).
This looks like a regression to me. Deleting the ->decltype(...) bit
makes the problem
go away but I need to stay within C+11.
* Can someone (STL?) confirm this is indeed a compiler bug?
* Any rewording of the code that might be generally applicable to C++11
so that I don't
have to include a specific workaround for VS 2017?
Thank you,
Joaquín M López Muñoz
