Dear Maintainer,

For years Gnus has had no problem reading the newsgroup
"gwene.com.fatwallet.hotdeals" from the news.gmane.org server.
Suddenly it's no longer possible to even enter the summary buffer for
this particular group.  After attempting to enter the summary buffer,
this is in the *messages* buffer:

===8<----------------------------------------
Retrieving newsgroup: nntp+news.gmane.org:gwene.com.fatwallet.hotdeals...
Fetching headers for nntp+news.gmane.org:gwene.com.fatwallet.hotdeals...
byte-code: Invalid read syntax: ". in wrong context"
Mark saved where search started
===8<----------------------------------------

A message in there must be corrupting the gnus parser.  I cannot even
delete the messages in the group to try to move forward, because I'm
blocked from the summary buffer.  The articles continue to download
okay, perhaps because I use the agent to download all groups for
offline reading:

 $ emacs -batch -l gnus.el -f gnus-agent-batch-fetch

Clearing the unread flags doesn't help.  Even if I could delete all
the messages, gnus-agent-batch-fetch would just retrieve them all
again anyway.

In any case, it should be investigated how a message could cause gnus
to fail in this apparently unrecoverable way.