advanced patterns when using std::variant with std::visit in C++17 leading to incorrect type handling
Hey everyone, I'm running into an issue that's driving me crazy. I'm working with an scenario with `std::variant` and `std::visit` in my C++17 application. I have a `std::variant<int, std::string>` which is meant to hold either an integer or a string, but when I use `std::visit` to process it, the results are not what I expect, especially when the variant holds a string. Here’s a simplified version of my code: ```cpp #include <iostream> #include <variant> #include <string> std::variant<int, std::string> myVariant; void processVariant(const std::variant<int, std::string>& v) { std::visit([](auto&& arg) { std::cout << "Value: " << arg << '\n'; }, v); } int main() { myVariant = std::string("Hello, World!"); processVariant(myVariant); return 0; } ``` When I run this, I expect it to print `Value: Hello, World!`, but I get the following behavior instead: ``` behavior: invalid initialization of non-static data member 'arg' from type 'const std::string&' ``` I’ve checked my code for any potential issues and confirmed that `myVariant` is correctly initialized with a string type. I've also tried replacing the lambda with a function pointer and that didn't help either. It seems like there's an scenario with how I've set up the lambda and the `std::visit`. What am I missing here? Is there a specific way I need to handle types within the lambda when using `std::visit` with a `std::variant`? Any insights would be greatly appreciated! My team is using C++ for this service. Thanks in advance!