Function from_json

3rd/nlohmann_json/single_include/nlohmann/json.hpp:3962–3969

{
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
{
    if (JSON_HEDLEY_UNLIKELY(!j.is_null()))
    {
        JSON_THROW(type_error::create(302, "type must be null, but is " + std::string(j.type_name()), j));
    }
    n = nullptr;
}

// overloads for basic_json template parameters
template < typename BasicJsonType, typename ArithmeticType,