Incrementing past-the-end iterator is not permitted by the standard, see [lib.input.iterators]. --- ginac/inifcns_nstdsums.cpp | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/ginac/inifcns_nstdsums.cpp b/ginac/inifcns_nstdsums.cpp index b410533..11a91dd 100644 --- a/ginac/inifcns_nstdsums.cpp +++ b/ginac/inifcns_nstdsums.cpp @@ -659,6 +659,8 @@ Gparameter::const_iterator check_parameter_G(const Gparameter& a, int scale, ++trailing_zeros; } } + if (lastnonzero == a.end()) + return a.end(); return ++lastnonzero; } -- 1.6.3.3