bug#64759: Broken faces

[Juri Linkov]

>> No, it's not the same.  The latter uses a white background on the mode line.
>
> So I ask again: what is the semantics of nil in this case?  We cannot
> have in Emacs something that triggers undefined behavior, let alone
> use it in our own sources.  The semantics of this must be known and
> documented before we can use it.

The semantics of nil could be the same as '((t nil)).

Do you agree that currently the value '((t nil))
should be used for faces without default face attributes?