It's quite ironic that on a page about safety they use an if statement without {} braces:

        if(x % 2)
          vec^.push_back(x);

        unsafe printf("%d\n", x);

Skipping the braces for single line conditionals in C++ is a lazy practice that almost inevitably leads to bugs, like Apple's famous goto fail bug: https://www.synopsys.com/blogs/software-security/understandi... . While memory bugs are difficult to prevent, this particular class of logic bug can be eliminated entirely just by always remembering to write two {} around the statement, so a language concerned with correctness should promote such good practices.

        if(x % 2){
          vec^.push_back(x);
        }