Thanks for the patch!
I noticed the patch also works for org-link, which had been a headache for me.

On Fri, Sep 18, 2020, at 04:52, Protesilaos Stavrou wrote:
> Ihor Radchenko <yantar92@gmail.com> [2020-09-17, 16:25 +0800]:
> 
> > The attached patch seems to fix the issue.
> > Can anyone test?

I also tested, with the following org file. Works well with one exception: the underline for org-link, which remains the color of itself. The reason is that face org-link inherits face link, which has :underline t in its setting. Therefore, it should be the expected behavior.
> * test ~code~ =verb= [[link]]
>   #+begin_src emacs-lisp
> (set-face-attribute 'org-level-1 nil :height 3.0 :weight 'normal)
> (set-face-attribute 'org-level-1 nil :weight 'bold)
> (set-face-attribute 'org-level-1 nil :background "white")
> (set-face-attribute 'org-level-1 nil :overline "yellow")
> (set-face-attribute 'org-level-1 nil :underline "red")
>   #+end_src


Sheng Yang(杨圣), PhD student
Computer Science Department
University of Maryland, College Park
E-mail: styang@fastmail.com
E-mail (old but still used): yangsheng6810@gmail.com