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

Calculating dependencies ...

!!! Problem resolving dependencies for =x11-misc/gpaste-3.42.5
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=x11-misc/gpaste-3.42.5" has unmet requirements.
- x11-misc/gpaste-3.42.5::gentoo USE="gnome -introspection (-systemd) -vala"

  The following REQUIRED_USE flag constraints are unsatisfied:
    gnome? ( introspection )

  The above constraints are a subset of the following complete expression:
    gnome? ( introspection ) vala? ( introspection )