patch 8.1.1299: "extends" from 'listchars' is used when 'list' is off

Problem:    "extends" from 'listchars' is used when 'list' is off. (Hiroyuki
            Yoshinaga)
Solution:   Only use the "extends" character when 'list' is on. (Hirohito
            Higashi, closes #4360)

src/screen.c

@@ -5594,8 +5594,10 @@ win_line(
 	    break;
 	}
 
-	/* line continues beyond line end */
-	if (lcs_ext
+	// Show "extends" character from 'listchars' if beyond the line end and
+	// 'list' is set.
+	if (lcs_ext != NUL
+		&& wp->w_p_list
 		&& !wp->w_p_wrap
 #ifdef FEAT_DIFF
 		&& filler_todo <= 0

src/testdir/test_listchars.vim

@@ -110,6 +110,25 @@ func Test_listchars()
   call cursor(1, 1)
   call assert_equal([expected], ScreenLines(1, virtcol('$')))
 
+  " test extends
+  normal ggdG
+  set listchars=extends:Z
+  set nowrap
+  set nolist
+  call append(0, [ repeat('A', &columns + 1) ])
+
+  let expected = repeat('A', &columns)
+
+  redraw!
+  call cursor(1, 1)
+  call assert_equal([expected], ScreenLines(1, &columns))
+
+  set list
+  let expected = expected[:-2] . 'Z'
+  redraw!
+  call cursor(1, 1)
+  call assert_equal([expected], ScreenLines(1, &columns))
+
   enew!
   set listchars& ff&
 endfunc

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1299,
 /**/
     1298,
 /**/