Answer by HolyBlackCat for C++20 std::async with template lambda of zero arguments

Just for completeness, if upgrading to C++23 is an option and the lambda is non-capturing, you can make it static:

#include <future>#include <array>int main(){    auto func = []<int n>() static    {        std::array<double, n> arr;        };    func.operator()<5>(); // This compiles.    std::async(func.operator()<5>); // This also compiles.}