This is a regression.

Steps to reproduce:
- modify Welcome sample in the following way
#include <iostream>

void go();

int main(int argc, char**argv) {
    // Prints welcome message...
    go();
    // Prints arguments...
    if (argc > 1) {
        std::cout << std::endl << "Arguments:" << std::endl;
        for (int i = 1; i < argc; i++) {
            std::cout << i << ": " << argv[i] << std::endl;
        }
    }
    
    return 0;
}

void go(){
    std::cout << "Welcome ..." << std::endl;
    
}

- in Navigator window call context menu on "go()" or main() and choose "Change Function Parameters..."

Result: "Change Function Parameters" window reports "Cannot refactor unresolved elements" error.