commit https://github.com/vim/vim/commit/33a80eeb859a78ba93432da6fa585786cfd77249 Author: Bram Moolenaar <Bram@vim.org> Date: Mon Sep 5 21:51:14 2016 +0200 patch 7.4.2331 Problem: Using CTRL-X CTRL-V to complete a command line from Insert mode does not work after entering an expression on the command line. Solution: Don't use "ccline" when not actually using a command line. (test by Hirohito Higashi)

" Test for joining lines.

func Test_join_with_count()
  new
  call setline(1, ['one', 'two', 'three', 'four'])
  normal J
  call assert_equal('one two', getline(1))
  %del
  call setline(1, ['one', 'two', 'three', 'four'])
  normal 10J
  call assert_equal('one two three four', getline(1))
  quit!
endfunc