main.rs

use cpp::cpp;
use cpp::cpp_class;

cpp!{{
    #include <iostream>
    
    using std::string;

    class Test {
    public:
        Test() {
            std::cout << "creating" << std::endl;
        }
        virtual ~Test() {
            std::cout << "destroying" << std::endl;
        }

    protected:
        std::string message; // -> removing this and we don't get the issue
    };
}}

cpp_class!(pub unsafe struct Test as "Test");
impl Test {
    fn new() -> Self {
        unsafe { cpp!([] -> Test as "Test" { return Test(); }) }
    }
}

fn main() {
    let test = Test::new();
}