This change appears to break vim-plug's on-demand loading mechanism.

This Plug call:

Plug 'elixir-editors/vim-elixir', {'for': 'elixir'}

... was previously sufficient to lazily load this plugin for both direct Elixir buffers (filetype elixir) as well as indirect usages, such as embedding the elixir syntax in fenced markdown code blocks via g:markdown_fenced_languages = ['elixir'].

The latter no longer works unless you also load vim-elixir for markdown buffers (Plug 'elixir-editors/vim-elixir', {'for': ['elixir', 'markdown']}).

I think the issue is more about the plugin/elixir.vim file itself rather than the g:loaded_elixir guard within it. I still see the issue if that file is entirely empty.

I don't have an alternate solution to propose, but it seems like this current approach is exposing some kind of flaw.

Interesting! I need to read up more on this but I'm totally happy to have this reverted.

Thanks for speaking up @jparise and apologies for messing with your workflow.

Reverted in #575