The problem is that it is now impossible to install gnome-light because of this problem. The dev-lang/spidermonkey package is not built with the current version of the rust-bin compiler I managed to solve my problem by fixing the rust compiler version to 1.77.1. Please consider fixing the compiler version for this package or solve the bug, it has killed a lot of nerve cells in my brain and (probably) right now there are people who are also experiencing it.
need emerge --info as a comment, and then either the full emerge output as a comment or build.log as an attachment (compressed, if necessary)
you can change the status back / reopen when the info is provided