Update (2021-03-31):

Just use neovim.coc instead of YouCompleteMe or Syntastic.

It's faster, easier to setup, and works intuitively. ALE is still wonderful and useful, though there's a lot of overlap - coc can lint as well.

Jump Lists and Change Lists

If you're going to be jumping around to where things are defined, you will need to know how to jump back again. It seems there are two lists you need to be aware of, the jump list¹ and the change list².

Jump List

• A list of locations that the cursor has jumped to.
• <C-O> move up the jump list
• <C-I> mode down the jump list
• Jumping to a definition, or a search result

Change List

• g; and g, → move up and down the change list
• A list of locations where a change was made.
• '. → go to the location of your last edit (. is a mark).
• '' → go back to where you were before your last jump

Original Post:

There are multiple ways of doing anything with vim, including going to where a function or object is defined, and I usually need to do something at least 3 times before I can do it without breaking my focus or train of thought.

My memory is hazy but I remember spending a 1/2 day looking into this and considering which solution I wanted to commit to.³ My options seemed to be between YouCompleteMe and ALE. [Update!⁴]

I can't remember everything I read and tried, but I trust my conclusions. Looking in my .vimrc I see that I have <leader>x mapped to :YcmCompleter GoTo and it works just fine, even when a module is imported from somewhere outside the current project. The tool was working and ready to use, I just hadn't internalized it yet.

Commands to remember:

• <Leader>x - GoTo definition - YCMs best guess at an 'intelligent' goto command, whether its a declaration or a definition.
• <F2> - Toggle tagbar