bug#42539: 28.0.50 font face in mode line problem ?

[Eli Zaretskii]

> From: Fabrice Popineau <fabrice.popineau@gmail.com>
> Date: Sat, 25 Jul 2020 21:21:36 +0200
> 
> ><------------------------------------------------------------------------------------><
> (set-face-font 'default "Roboto Mono Light 14")
> 
> (set-fontset-font "fontset-default"  '(#x2600 . #x26ff) "Fira Code 16")
> 
> (defun mode-line-render (left right)
>   (let* ((available-width (- (window-width) (length left) )))
>     (format (format "%%s %%%ds" available-width) left right)))
> 
> (setq-default mode-line-format
>      '((:eval
>         (mode-line-render
> (format-mode-line
>  (list
>   (propertize "☰" 'face `(:inherit mode-line-buffer-id)
>                        'help-echo "Mode(s) menu"
>                        'mouse-face 'mode-line-highlight
>                        'local-map   mode-line-major-mode-keymap)
>            " %b "
>            (if (and buffer-file-name (buffer-modified-p))
>                (propertize "(modified)" 'face `(:inherit face-faded)))))
> (format-mode-line
>           (propertize "%4l:%2c  " 'face `(:inherit face-faded)))))))
> ><------------------------------------------------------------------------------------><
> When evalutating this code from `emacs -Q', the intended character is never 
> displayed (I assume that it is
> because it is not looked in the Fira Code font)

Does it help to give the nil value to use-default-font-for-symbols?