• Do you have libgccjit installed and GCC and Binutils on PATH?

Can confirm it was a mishandled msys2 path, sorry about that.

On the other hand I confirm this bug still happens under WSL Ubuntu for emacs30 but not for emacs 28.2, haven’t tried emacs29 and my config depends on some things

and features in emacs29, gonna wait until pretest I guess.