avoid warnings

libsrc/core/archive.hpp

@@ -729,6 +729,8 @@ namespace ngcore
     Archive& operator&(std::tuple<T...> &t)
     {
       // call operator& for each element of the tuple
+      // std::ignore to avoid MSVC warning 
+      std::ignore =     
         std::apply([this](auto&... arg) { std::make_tuple(((*this) & arg).IsParallel()...);}, t);
       return *this;
     }

libsrc/core/ng_mpi.cpp

@@ -49,7 +49,7 @@ void gather_strided_array(size_t count, char* data) {
   if constexpr (size < stride) {
     char* dst = data;
     char* src = data;
-    for (auto i : Range(count)) {
+    for ( [[maybe_unused]] auto i : Range(count)) {
       memcpy(dst, src, size);
       dst += size;
       src += stride;