:map <c-n> showing multiple maps when not being set in .vimrc

Question

I have this added to my vimrc

map <C-n> :cnext<CR>
map <C-m> :cprevious<CR>
nnoremap <leader>a :cclose<CR>

This is from vim-go-tutorial here.

While after running a simple :GoBuild with some errors, while trying to jump to the next error, it doesn't do as intended jump to the next definition. While doing :cnext and then doing a <C-m> works and executes :cprevious

While in the file, I tried running :map <c-m> and it only shows being mapped to :cprevious which is why this command was working in the first place, but then when I tried doing a :map <c-n>, It showed me a couple of things being mapped

x  <C-N>       * :<C-U>call multiple_cursors#new("v", 0)<CR>
n  <C-N>       * :call multiple_cursors#new("n", 1)<CR>
os <C-N>         :cnext<CR>

While I don't have the other two mappings being showed in my vimrc, how do I remove these two other invocations and just have :cnext

Answer 1

They were added by a plugin

It looks like these mappings are added by the vim-multiple-cursors plugin.

To prevent that plugin from overriding your <C-n> mapping, you can either remove the plugin (the fact that you didn't recognise it suggests you don't use it?) or tell it not to create mappings and set up your own:

let g:multi_cursor_use_default_mapping=0

" Default mapping
"let g:multi_cursor_start_word_key      = '<C-n>' USE SOMETHING ELSE INSTEAD
"                                         OF `<C-n>` HERE
let g:multi_cursor_select_all_word_key = '<A-n>'
let g:multi_cursor_start_key           = 'g<C-n>'
let g:multi_cursor_select_all_key      = 'g<A-n>'
let g:multi_cursor_next_key            = '<C-n>' AND PROBABLY HERE
let g:multi_cursor_prev_key            = '<C-p>'
let g:multi_cursor_skip_key            = '<C-x>'
let g:multi_cursor_quit_key            = '<Esc>'

N.B. The vim-multiple-cursors GitHub page has a massive banner saying that the plugin is deprecated and that you should use vim-visual-multi instead. Note that vim-visual-multi also overrides <C-n> by default, but has a different mechanism for changing the mapping it uses.

Using both sets of mappings

If you only want to use your <C-n> mapping in Go files, and want to use the vim-multiple-cursors plugin's mapping elsewhere, then you could instead set up your mappings for the Go filetype by creating the file ~/.vim/after/ftplugin/go if it doesn't already exist, and then adding your mapping as a buffer-local mapping in that file:

nnoremap <buffer> <C-n> :cnext<CR>
nnoremap <buffer> <C-m> :cprevious<CR>