patch 8.0.0571: negative line number when using :z^ in an empty buffer commit https://github.com/vim/vim/commit/a364cdb648ae009fa7aa05382f5659335683d349 Author: Bram Moolenaar <Bram@vim.org> Date: Thu Apr 20 21:12:30 2017 +0200 patch 8.0.0571: negative line number when using :z^ in an empty buffer Problem: The cursor line number becomes negative when using :z^ in an empty buffer. (neovim https://github.com/vim/vim/issues/6557) Solution: Correct the line number. Also reset the column.

--- a/src/testdir/test_ex_z.vim
+++ b/src/testdir/test_ex_z.vim
@@ -68,7 +68,7 @@ func Test_z()
   bw!
 endfunc
 
-func Test_z_bug()
+func Test_z_overflow()
   " This used to access invalid memory as a result of an integer overflow
   " and freeze vim.
   normal ox
@@ -76,3 +76,10 @@ func Test_z_bug()
   z777777776666666
   ')
 endfunc
+
+func Test_z_negative_lnum()
+  new
+  z^
+  call assert_equal(1, line('.'))
+  bwipe!
+endfunc