emerge --info [this-is-not-a-valid-atom] currently outputs as if the invalid atom has not been included. Since this leads incomplete output, bug wrangling then requires extra steps on both parts to get the required information (viz. the equivalent of `emerge -vpq [atom]'). It should instead recognise that the atom is invalid and output an error and nothing else.
This is fixed in git: http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=437c0f1987fa770bd2edf31f1a5a1812391e37fd
Now enhanced with search for similar names: http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=372d0e0dced3f94ba619e722e8a87f0256d52aea
This is fixed in 2.1.11.32 and 2.2.0_alpha143.