diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index bdd3642f..d27940b8 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -5678,7 +5678,7 @@ class binary_reader
                     const int exp = (half >> 10u) & 0x1Fu;
                     const unsigned int mant = half & 0x3FFu;
                     assert(0 <= exp and exp <= 32);
-                    assert(0 <= mant and mant <= 1024);
+                    assert(mant <= 1024);
                     switch (exp)
                     {
                         case 0:
@@ -12044,13 +12044,12 @@ class binary_writer
     */
     static std::size_t calc_bson_array_size(const typename BasicJsonType::array_t& value)
     {
-        std::size_t embedded_document_size = 0ul;
         std::size_t array_index = 0ul;
 
-        for (const auto& el : value)
+        const std::size_t embedded_document_size = std::accumulate(std::begin(value), std::end(value), 0ul, [&array_index](std::size_t result, const typename BasicJsonType::array_t::value_type & el)
         {
-            embedded_document_size += calc_bson_element_size(std::to_string(array_index++), el);
-        }
+            return result + calc_bson_element_size(std::to_string(array_index++), el);
+        });
 
         return sizeof(std::int32_t) + embedded_document_size + 1ul;
     }