Infinite recursion
Using ipython version 7.5.0, python 3.7.3, anaconda 1.7.2, Ubuntu 18.04, Linux 4.15.0-51-generic, I cloned the git repository and ran python install.py. Then I ran ipython (it warned me to move the newly installed package to site-packaged instead, which I did, although this seems not to matter much.) Then I tested using gc.collect() without first importing. If barfed into an infinite recursion and I had to close the terminal. Looking through the source and this page (https://ipython.readthedocs.io/en/stable/api/generated/IPython.core.interactiveshell.html), it looks like all that is needed is to change run_code to run_cell since the string is not compiled. Indeed, making this small change fixed the issue for me.