commit https://github.com/vim/vim/commit/7069bf18e1b1b7bc7640335e07d1022b5acc9048 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Jan 7 20:39:53 2017 +0100 patch 8.0.0150: completion for :filter does not skip the pattern Problem: When the pattern of :filter does not have a separator then completion of the command fails. Solution: Skip over the pattern. (Ozaki Kiichi, clodes #1299)

" Test feedkeys() function.

func Test_feedkeys_x_with_empty_string()
  new
  call feedkeys("ifoo\<Esc>")
  call assert_equal('', getline('.'))
  call feedkeys('', 'x')
  call assert_equal('foo', getline('.'))

  " check it goes back to normal mode immediately.
  call feedkeys('i', 'x')
  call assert_equal('foo', getline('.'))
  quit!
endfunc