That error likely means either Coqtail wasn't installed correctly, it didn't load because of the file type, or it doesn't support your version of Vim/NeoVim.
To check for the first case, see if Coqtail is in your Vim runtime path (:echo &rtp
). If not, double check that you didn't miss a step while installing with whatever package manager you're using (e.g., forgetting to do :PlugInstall
with vim-plug). See https://github.com/whonore/Coqtail#installation-and-requirements for some options.
If it is installed, make sure the buffer you're editing has filetype=coq
. This should be set automatically if you open a .v
file, but you can also set it manually with :set ft=coq
.
Finally, if everything is installed and you're editing a Coq file, check if g:coqtail#supported
is 0
. Coqtail requires Python 3.6 or newer and it will fail to load and print an error if your Vim/NeoVim installation doesn't have it.