lambda-coerce.cpp

// When using first-class functions, c++11 will silently coerce a function returning a value
//  into a std::function returning a reference, thus creating a ticking time bomb.

#include <stdio.h>
#include <functional>

const int& f1 (std::function<const int& ()> func) {
    return func();
};

int f () { return 4; }

int main () {
    const int& p = f1(f);
    printf("%d\n", p);  // Prints 32767 or somesuch.
    return 0;
}