bo0ts/expand-region.el — comment on commit 83644ffdee46786bdc3db0d54be286493b3c1e95
File:  line 0
By gvol:

I made `er/mark-defun` for modes where `er/mark-outside-pairs` doesn't work, like `c++-mode`, and thought I would turn it on everywhere since it's always defined and that's how I found the bug.