https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79406
--- Comment #1 from Jean-Michaƫl Celerier <jeanmichael.celerier at gmail dot com> --- This stems from the usage of the following lambda expression : [&] (auto&&... args) { return this->fun(std::forward<decltype(args)>(args)...); } Unlike bug 77950 the enclosing function is not a template but a simple class constructor that takes two int16_t. The arguments passed to the lambda are either : * (std::weak_ptr<void>) * (std::weak_ptr<void>, const std::string&)