#include <cassert>
#include <memory>
#include <stdexcept>

struct Worker {
    static int alive;
    Worker() { ++alive; }
    ~Worker() { --alive; }
};
int Worker::alive = 0;

void run(bool fail) {
    auto worker = std::make_unique<Worker>();
    if (fail) throw std::runtime_error("cancelled");
}

int main() {
    bool caught = false;
    try { run(true); }
    catch (const std::runtime_error&) { caught = true; }
    assert(caught && Worker::alive == 0);
    run(false);
    assert(Worker::alive == 0);
}