[Bug c++/72789] add -Wunused-private-field

[jean-christian.cirstea at tuta dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72789

--- Comment #5 from Jean-Christian CÎRSTEA <jean-christian.cirstea at tuta dot 
com> ---
A [patch](https://gcc.gnu.org/pipermail/gcc-patches/2026-March/711320.html) has
been sent.