vim-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 vim/vim#4360)
a5c6a0b6c7

src/nvim/screen.c

@@ -3995,8 +3995,10 @@ win_line (
       break;
     }
 
-    // line continues beyond line end
+    // Show "extends" character from 'listchars' if beyond the line end and
-    if (wp->w_p_lcs_chars.ext
+    // 'list' is set.
+    if (wp->w_p_lcs_chars.ext != NUL
+        && wp->w_p_list
         && !wp->w_p_wrap
         && filler_todo <= 0
         && (wp->w_p_rl ? col == 0 : col == grid->Columns - 1)

src/nvim/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