--?     print('', '', #pane.line_cache[i].screen_line_starting_pos, pane.left, pane.right)

  Text.populate_screen_line_starting_pos(pane, loc.line)
  for i,screen_line_starting_pos in ipairs(pane.line_cache[loc.line].screen_line_starting_pos) do
    assert(screen_line_starting_pos <= loc.pos)
    if screen_line_starting_pos == loc.pos then
      break
    end
    result = result + Line_height
  end