https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122062
--- Comment #2 from 康桓瑋 <hewillk at gmail dot com> --- (In reply to Jonathan Wakely from comment #1) > --- a/libstdc++-v3/include/bits/random.tcc > +++ b/libstdc++-v3/include/bits/random.tcc > @@ -83,7 +83,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > __normalize(_InputIterator __first, _InputIterator __last, > _OutputIterator __result, const _Tp& __factor) > { > - for (; __first != __last; ++__first, ++__result) > + for (; __first != __last; ++__first, (void) ++__result) > *__result = *__first / __factor; > return __result; > } > @@ -3197,7 +3197,7 @@ namespace __detail > _InputIteratorW __wbegin) > : _M_int(), _M_den(), _M_cp(), _M_m() > { > - for (; __bbegin != __bend; ++__bbegin, ++__wbegin) > + for (; __bbegin != __bend; ++__bbegin, (void) ++__wbegin) > { > _M_int.push_back(*__bbegin); > _M_den.push_back(*__wbegin); __normalize doesn't seem to be needed, since it only takes vector::iterator.