These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.10 s (backtrack: 0/20).


The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
>=app-crypt/gcr-4.4.1 introspection
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
>=gui-libs/gtk-4.22.5-r1 introspection
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
=x11-wm/mutter-48.8 introspection
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
>=sys-auth/polkit-126-r3 introspection
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
>=gnome-base/gsettings-desktop-schemas-50.1 introspection
# required by gnome-base/gnome-shell-48.8::gentoo[networkmanager]
# required by =gnome-base/gnome-shell-48.8 (argument)
>=net-misc/networkmanager-1.58.1-r3 introspection
# required by gnome-base/gnome-shell-48.8::gentoo[networkmanager]
# required by =gnome-base/gnome-shell-48.8 (argument)
>=net-libs/libnma-1.10.6-r2 introspection
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
>=app-accessibility/at-spi2-core-2.60.7 introspection
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
>=x11-libs/gdk-pixbuf-2.44.8 introspection
# required by gnome-base/gnome-shell-48.8::gentoo
# required by =gnome-base/gnome-shell-48.8 (argument)
>=sys-apps/accountsservice-26.27.3 introspection
# required by gnome-base/gnome-shell-48.8::gentoo[ibus]
# required by =gnome-base/gnome-shell-48.8 (argument)
>=app-i18n/ibus-1.5.34-r2 introspection

!!! The ebuild selected to satisfy ">=sys-apps/accountsservice-0.6.14[introspection]" has unmet requirements.
- sys-apps/accountsservice-26.27.3::gentoo USE="-doc -elogind -gtk-doc -introspection (-selinux) (-systemd) -test -vala -xcrypt"

  The following REQUIRED_USE flag constraints are unsatisfied:
    exactly-one-of ( elogind systemd )

(dependency required by "gnome-base/gnome-shell-48.8::gentoo" [ebuild])
(dependency required by "=gnome-base/gnome-shell-48.8" [argument])