commit https://github.com/vim/vim/commit/5cefd4098204b4677387511b586673649f2fab48 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Feb 16 12:44:26 2016 +0100 patch 7.4.1329 Problem: Crash when using channel that failed to open. Solution: Check for NULL. Update messages. (Yukihiro Nakadaira)

--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -318,3 +318,9 @@ endfunc
 func Test_unlet_handle()
   call s:run_server('s:unlet_handle')
 endfunc
+
+func Test_open_fail()
+  silent! let ch = ch_open("noserver")
+  echo ch
+  let d = ch
+endfunc