Undefining freed stack space

I have been guilty in the past of accessing out-of-scope data. It fortunately hasn’t happened recently, but I know I sometimes have not immediately noticed, when I did. Delayed noticing in particular happened, when the data was accessed directly after the function returned. There have been cases where I only noticed that there was a problem, when the code contained an intermediate function call, that in turn overwrote a small part of the stack, before the program accessed the out-of-scope data...