commit https://github.com/vim/vim/commit/fe38b494fff56cd9b2fcaeef26a8fd7b6557d69c Author: Bram Moolenaar <Bram@vim.org> Date: Sun Dec 11 21:34:23 2016 +0100 patch 8.0.0133 Problem: "2;'(" causes ml_get errors in an empty buffer. (Dominique Pelle) Solution: Check the cursor line earlier.

--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -234,3 +234,10 @@ func Test_remove_char_in_cmdline()
   call feedkeys(":abc def\<S-Left>\<C-U>\<C-B>\"\<CR>", 'tx')
   call assert_equal('"def', @:)
 endfunc
+
+func Test_illegal_address()
+  new
+  2;'(
+  2;')
+  quit
+endfunc