Before filing a bug, please ensure that your configuration is not the cause of
the bug.  At the very least, this can help narrow down exactly where the bug
exists or what option is causing the behavior.

If the potential bug is part of Vim's basic functionality, run

  (g)vim -u NONE -U NONE -N

If the potential bug is part of Vim's plugins, run

  (g)vim -u NORC -U NORC -N

If the potential bug is part of Vim's filetype-specific functionality, run

  (g)vim -u NORC -U NORC --cmd 'filetype plugin indent on' -N