when there is no index file

[積丹尼 Dan Jacobson]

Messages like
user-error: No ‘file’ in index
user-error: No ‘a’ in index
would better be
user-error: No Index file found.

Or noting when reading the gv manual,

    i runs the command Info-index (found in Info-mode-map),
    ...
    Give an empty topic name to go to the Index node itself.

OK I did, but ended up on
(info "(gv) GNU General Public License")

One notes if one is at the very top, one sees
     byte-code: The Info directory node has no index; use m to select a manual
so that case is already covered.