[Bug c++/67268] demangler does not elide empty argument pack in operator()

[ian at airs dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67268

--- Comment #1 from Ian Lance Taylor <ian at airs dot com> ---
This symbol shows a similar, though perhaps not identical, issue:

_ZNSt11_Tuple_implILm0EJN12stats_census7tracing2OpEEEC2IRS2_JEvEEOT_DpOT0_

The demangler turns this into

std::_Tuple_impl<0ul,
stats_census::tracing::Op>::_Tuple_impl<stats_census::tracing::Op&, ,
void>(stats_census::tracing::Op&)


It should be

std::_Tuple_impl<0ul,
stats_census::tracing::Op>::_Tuple_impl<stats_census::tracing::Op&,
void>(stats_census::tracing::Op&)