How can I write an inline recursive lambda in C++?

Question

As I know in C++17, I can write a recursive lambda like this:

auto dfs = [&](const auto &self, int x) -> void {
    // ....
    self(self, x);
};

dfs(dfs, 0);

Unfortunately, I have to endure one more parameter which is a bit ugly. And I doubt the possibility for the compiler to make it inline. Are there new options in new C++ standards? (C++20 or C++23)

Answer 1

You can use an explicit object parameter with a deduced type:

auto dfs = [&](this const auto &self, int x) -> void {
    // ....
    self(x);
};

dfs(0);  // `self` is `dfs`

This is a C++23 feature