David Ford (FirefighterBlu3) added the comment:
> @stinner your traceback suggestion was highly useful and much appreciated. i have spent several dozen hours researching ResourceWarnings in the past and tearing my hair out because the emitted warning was very much useless. i couldn't even make educated guesses about the code as socket pairs were used randomly.

So did I. Why do you think that I implemented this feature? :-D

> i strongly approve of mentioning the tracemalloc / traceback in the warning, and i would also very much encourage saying "this filename:position could be completely wrong" or do away with it all together.

I dislike removing filename:line information: in some cases, the
information is valid and helps to understand a warning.

Ok, let's go to add a line suggestion to enable tracemalloc. Is there
someone here interested to propose a pull request? It should only be
done in Python 3.7 and later 3.6, it's a new feature in Python 3.6.