In case of input iterators, the loop that assigns to existing elements should run up to number of elements in vector (_M_size) not capacity (_Nm).
PR libstdc++/119137 libstdc++-v3/ChangeLog: * include/std/inplace_vector (inplace_vector::assign_range): Replace _Nm with _M_size in the assigment loop. --- This obvious type was detected by adding more constexpr test, that I will post later. Committing it direclty, as this is new C++26 code. Pushed to trunk. libstdc++-v3/include/std/inplace_vector | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libstdc++-v3/include/std/inplace_vector b/libstdc++-v3/include/std/inplace_vector index e0943f52ab8..290cf6eb0e9 100644 --- a/libstdc++-v3/include/std/inplace_vector +++ b/libstdc++-v3/include/std/inplace_vector @@ -269,7 +269,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION auto __in = ranges::begin(__rg); auto __end = ranges::end(__rg); size_type __n = 0; - for (; __n < _Nm && __in != __end; ++__in) + for (; __n < _M_size && __in != __end; ++__in) _M_elems[__n++] = *__in; if (__in == __end) -- 2.49.0