https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108948
Bug ID: 108948
Summary: <unresolved overloaded function type> for function
template with auto return and parameter pack
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: egpt.gcc at wolke7 dot net
Target Milestone: ---
Hello,
consider the following code (with -std=c++17):
------------------------------------------------------------------
#include <tuple>
template <typename... Types>
auto add1(const Types... x) { return std::make_tuple((x+1)...); }
int main() {
auto x = std::apply(add1<int,int>, std::make_tuple(10,20));
return 0;
}
------------------------------------------------------------------
Compiling with g++ 12.2.0 (Debian testing) yields the following error message:
------------------------------------------------------------------
add1.cpp: In function 'int main()':
add1.cpp:11:29: error: invalid initialization of non-const reference of type
'std::tuple<int, int> (&)(int, int)' from an rvalue of type '<unresolved
overloaded function type>'
11 | auto x = std::apply(add1<int,int>, t);
| ^~~~~~~~~~~~~
------------------------------------------------------------------
Both, clang++ 14.0.6 (Debian testing) and icpx 2023.0.0 compile just fine. It
seems related to the resolved bug 64194. It works with add1 being defined
without parameter pack as follows:
------------------------------------------------------------------
template <typename Type1, typename Type2>
auto add1(const Type1 x, const Type2 y) { return std::make_tuple(x+1,y+1); }
------------------------------------------------------------------
Kind regards
Elmar
