Not trying to be picky, but memory leak has its own meaning.

A piece of memory is said to be leaked, if there is no way the program can free it, as the handler to that piece of memory is lost because of mistakes.

A piece of code can be coded in such a way, that it does not free memories that it no longer want. That is not memory leak, although that is quite careless, as long as you still have the handler. If you want, you still can free it, as you still have the handler, so the momery is not leaked.

In general, pure Perl code does not cause memory leak.