https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67796
Bug ID: 67796
Summary: Definition for custom std::swap found by ADL but not
used
Product: gcc
Version: 5.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rkirchge at gmail dot com
Target Milestone: ---
I am trying to use ADL to find a custom implementation of swap for tuples of an
reference types. I am compiling with "-std=c++14 -Wall -Wextra".
Without the following definition, the compiler reports that it cannot find the
function required. With the code, the compilation succeeds without warning but
"ADL works" does not print.
namespace std {
template <typename... T>
void swap(std::tuple<T&...> lhs, std::tuple<T&...> rhs) noexcept
{
std::cout<<"ADL works!"<<std::endl;
std::tuple<T...> tmp = lhs;
lhs = rhs;
rhs = tmp;
}
>From my tests the swap function being used when I include the above code
behaves as:
auto tmp = lhs;
lhs = rhs;
rhs = lhs;
But since these are std::tuples of reference types, the temporary value created
is also a tuple of reference types, so it does not work as I intend.
