makeinfo gets confused by @ref command inside @copying

[Bruno Haible]

Hi,

makeinfo fails with the same error message as reported in
  <http://lists.gnu.org/archive/html/bug-texinfo/2008-01/msg00024.html>

$ makeinfo --version
makeinfo (GNU texinfo) 4.13
...
$ makeinfo foo.texi
/tmp//foo.texi:41: Next field of node `Top' not pointed to (perhaps incorrect 
sectioning?).
/tmp//foo.texi:68: This node (Introduction) has the bad Prev.
makeinfo: Removing output file `/tmp/libunistring.info' due to errors; use 
--force to preserve.

The error goes away when I comment out or remove line 21, which contains a 
@ref{...}
command.

Bruno

foo.texi
Description: Text Data