When I use imap or inoremap to create any shortcut in Neovim 0.2.0, the shortcuts seem to act as if they are not there! Here is an example that I just tried.
nnoremap <F2> :w!<CR> vnoremap <F2> <Esc>:w!<CR>gv inoremap <F2> <Esc>:w!<CR>gi
The insert mode mapping just types in the key combination when I enter it in insert mode. However, the normal and visual mode mappings work just fine. I have tried other combinations such as
C-s and others.
P.S. I have
stty -ixon in my shell rc file.