How to highlight tabs in Emacs

Question

I use spaces for indentation in source code, how can I highlight/mark tabs, that are in code?

It could be red, the same as when I use (setq-default show-trailing-whitespace t)

Answer 1

As a hint from @abo-abo I found that I can use whitespace-mode with this code:

(setq whitespace-style '(face tabs))
(whitespace-mode)