vim-patch:8.2.1957: diff and cursorcolumn highlighting don't mix

Problem:    Diff and cursorcolumn highlighting don't mix.
Solution:   Fix condition for what attribute to use. (Christian Brabandt,
            closes vim/vim#7258, closes vim/vim#7260)
fabc3ca896

src/nvim/screen.c

@@ -4139,8 +4139,11 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow,
     // Also highlight the 'colorcolumn' if it is different than
     // 'cursorcolumn'
     vcol_save_attr = -1;
-    if (draw_state == WL_LINE && !lnum_in_visual_area
-        && search_attr == 0 && area_attr == 0) {
+    if (draw_state == WL_LINE
+        && !lnum_in_visual_area
+        && search_attr == 0
+        && area_attr == 0
+        && filler_todo <= 0) {
       if (wp->w_p_cuc && VCOL_HLC == (long)wp->w_virtcol
           && lnum != wp->w_cursor.lnum) {
         vcol_save_attr = char_attr;

src/nvim/testdir/test_diffmode.vim

@@ -1148,5 +1148,38 @@ func Test_diff_and_scroll()
   set ls&
 endfunc
 
+func Test_diff_filler_cursorcolumn()
+  CheckScreendump
+
+  let content =<< trim END
+    call setline(1, ['aa', 'bb', 'cc'])
+    vnew
+    call setline(1, ['aa', 'cc'])
+    windo diffthis
+    wincmd p
+    setlocal cursorcolumn foldcolumn=0
+    norm! gg0
+    redraw!
+  END
+  call writefile(content, 'Xtest_diff_cuc')
+  let buf = RunVimInTerminal('-S Xtest_diff_cuc', {})
+
+  call VerifyScreenDump(buf, 'Test_diff_cuc_01', {})
+
+  call term_sendkeys(buf, "l")
+  call term_sendkeys(buf, "\<C-l>")
+  call VerifyScreenDump(buf, 'Test_diff_cuc_02', {})
+  call term_sendkeys(buf, "0j")
+  call term_sendkeys(buf, "\<C-l>")
+  call VerifyScreenDump(buf, 'Test_diff_cuc_03', {})
+  call term_sendkeys(buf, "l")
+  call term_sendkeys(buf, "\<C-l>")
+  call VerifyScreenDump(buf, 'Test_diff_cuc_04', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('Xtest_diff_cuc')
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab