+" Same for <C-@> (insert previously inserted text and leave insert mode).
+inoremap <C-@> <C-G>u<C-@>
+" And for <C-A> (insert previously inserted text).
+inoremap <C-A> <C-G>u<C-A>
+" And for <C-W> (delete word before cursor).
+inoremap <C-W> <C-G>u<C-W>