braces in xrefs failure with texinfo.tex

[Karl Berry]

Hi Gavin - somewhere in all the brace/indexing changes to texinfo.tex,
it seems that using @{ or @} inside @xref or other ref commands started
to fail (or maybe it never worked, I guess I'm not entirely sure, come
to think of it).  Now, something like

  @address@hidden

gets (with texinfo.tex 2016-01-11.19):
  ./refbrace.tex:4: Missing @endcsname inserted.
  <to be read again> 
                     @indexrbrace 
  @}->address@hidden 
  ...
                    }
  <argument> address@hidden
                b
  @xrefX address@hidden @Xthisreftitle @csname XR#1

Passing on since I saw it.  I can't delve into it right now, but if you
don't have time I can get to it eventually.  --thanks, k.


Trivial example file:
------
\input texinfo
@setfilename refbrace.info

@address@hidden
@address@hidden

@bye