patch 9.0.2159: screenpos() may crash with neg. column

Problem:  screenpos() may crash with neg. column
Solution: validate and correct column

closes: #13669

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/move.c b/src/move.c
index fbb352a..861d84b 100644
--- a/src/move.c
+++ b/src/move.c
@@ -1531,6 +1531,8 @@
 	return;
     }
     pos.col = tv_get_number(&argvars[2]) - 1;
+    if (pos.col < 0)
+	pos.col = 0;
     pos.coladd = 0;
     textpos2screenpos(wp, &pos, &row, &scol, &ccol, &ecol);
 
diff --git a/src/testdir/test_cursor_func.vim b/src/testdir/test_cursor_func.vim
index 3cdf4cb..2bdda86 100644
--- a/src/testdir/test_cursor_func.vim
+++ b/src/testdir/test_cursor_func.vim
@@ -206,6 +206,11 @@
   nmenu WinBar.TEST :
   call assert_equal(#{col: 1, row: 2, endcol: 1, curscol: 1}, screenpos(win_getid(), 1, 1))
   nunmenu WinBar.TEST
+  call assert_equal(#{col: 1, row: 1, endcol: 1, curscol: 1}, screenpos(win_getid(), 1, 1))
+
+  call assert_equal(#{col: 0, row: 0, endcol: 0, curscol: 0}, screenpos(0, 0, 1))
+  call assert_equal(#{col: 0, row: 0, endcol: 0, curscol: 0}, screenpos(0, -1, 1))
+  call assert_equal(#{col: 1, row: 1, endcol: 1, curscol: 1}, screenpos(0, 1, -v:maxcol))
 endfunc
 
 func Test_screenpos_fold()
diff --git a/src/version.c b/src/version.c
index 4bb1c90..15ff51d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2159,
+/**/
     2158,
 /**/
     2157,