diff --git a/include/nlohmann/detail/output/binary_writer.hpp b/include/nlohmann/detail/output/binary_writer.hpp
index d3495a4bb..232e97d5c 100644
--- a/include/nlohmann/detail/output/binary_writer.hpp
+++ b/include/nlohmann/detail/output/binary_writer.hpp
@@ -1110,7 +1110,7 @@ class binary_writer
 
         const std::size_t embedded_document_size = std::accumulate(std::begin(value), std::end(value), static_cast<std::size_t>(0), [&array_index](std::size_t result, const typename BasicJsonType::array_t::value_type & el)
         {
-            return result + calc_bson_element_size(std::to_string(array_index++), el);
+            return result + calc_bson_element_size(static_cast<string_t>(std::to_string(array_index++)), el);
         });
 
         return sizeof(std::int32_t) + embedded_document_size + 1ul;
@@ -1137,7 +1137,7 @@ class binary_writer
 
         for (const auto& el : value)
         {
-            write_bson_element(std::to_string(array_index++), el);
+            write_bson_element(static_cast<string_t>(std::to_string(array_index++)), el);
         }
 
         oa->write_character(to_char_type(0x00));
diff --git a/include/nlohmann/detail/output/output_adapters.hpp b/include/nlohmann/detail/output/output_adapters.hpp
index 630bd8f73..0f5934035 100644
--- a/include/nlohmann/detail/output/output_adapters.hpp
+++ b/include/nlohmann/detail/output/output_adapters.hpp
@@ -124,7 +124,10 @@ class output_adapter
   public:
     template<typename AllocatorType = std::allocator<CharType>>
     output_adapter(std::vector<CharType, AllocatorType>& vec)
-        : oa(std::make_shared<output_vector_adapter<CharType, AllocatorType>>(vec)) {}
+    {
+        AllocatorType alloc;
+        oa = std::allocate_shared<output_vector_adapter<CharType, AllocatorType>>(alloc, vec);
+    }
 
 #ifndef JSON_NO_IO
     output_adapter(std::basic_ostream<CharType>& s)