The following code tries to create a templated lambda and pass it to a function that calls it. However compilation fails because the type of lambda argument is wrong.

#include <functional>

void foo(std::function<void(void)>&lambda) {
  lambda.template operator()<int>();
}

int main() {
  auto f = []<class T>() {};
  foo(f);
}

How should I define the type of an argument that receives a templated lambda?

Using auto works but I need the explicit type (so I can modify foo to return whatever the lambda returns).

void foo(auto &lambda) { // Works but not what I want

I tried this but doesn’t compile:

template<class T>
void foo(std::function<void<T>(void)>&lambda) {