Repository: nlohmann/json
File: src/json.hpp (C++)

Code before:
        /// array (stored with pointer to save storage)
        array_t* array;
        /// string (stored with pointer to save storage)
        string_t* string;
        /// boolean
        boolean_t boolean;
        /// number (integer)
        number_integer_t number_integer;
        /// number (unsigned integer)
        number_unsigned_t number_unsigned;
        /// number (floating-point)
        number_float_t number_float;

        /// default constructor (for null values)
        json_value() = default;
        /// constructor for booleans
        json_value(boolean_t v) noexcept : boolean(v) {}
        /// constructor for numbers (integer)
        json_value(number_integer_t v) noexcept : number_integer(v) {}
        /// constructor for numbers (unsigned)
        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
        /// constructor for numbers (floating-point)
        json_value(number_float_t v) noexcept : number_float(v) {}
        /// constructor for empty values of a given type
        json_value(value_t t)
            : object(nullptr)
        {
            switch (t)
            {
                case value_t::object:
                {
                    object = create<object_t>();
                    break;
                }

                case value_t::array:
                {
                    array = create<array_t>();
                    break;
                }

                case value_t::string:
                {
                    string = create<string_t>("");
                    break;
                }

                case value_t::boolean:
                {
                    boolean = boolean_t(false);
                    break;

Review comment (bug):
If this is required, then maybe we can remove the lines

```cpp
object = nullptr;  // silence warning, see #821
```

below which have been added when discussing #821.

Code after:
    /// helper for exception-safe object creation
    template<typename T, typename... Args>
    static T* create(Args&& ... args)
    {
        AllocatorType<T> alloc;
        using AllocatorTraits = std::allocator_traits<AllocatorType<T>>;

        auto deleter = [&](T * object)
        {
            AllocatorTraits::deallocate(alloc, object, 1);
        };
        std::unique_ptr<T, decltype(deleter)> object(AllocatorTraits::allocate(alloc, 1), deleter);
        AllocatorTraits::construct(alloc, object.get(), std::forward<Args>(args)...);
        assert(object != nullptr);
        return object.release();
    }

    ////////////////////////
    // JSON value storage //
    ////////////////////////

    /*!
    @brief a JSON value

    The actual storage for a JSON value of the @ref basic_json class. This
    union combines the different storage types for the JSON value types
    defined in @ref value_t.

    JSON type | value_t type    | used type
    --------- | --------------- | ------------------------
    object    | object          | pointer to @ref object_t
    array     | array           | pointer to @ref array_t
    string    | string          | pointer to @ref string_t
    boolean   | boolean         | @ref boolean_t
    number    | number_integer  | @ref number_integer_t
    number    | number_unsigned | @ref number_unsigned_t
    number    | number_float    | @ref number_float_t
    null      | null            | *no value is stored*

    @note Variable-length types (objects, arrays, and strings) are stored as
    pointers. The size of the union should not exceed 64 bits if the default
    value types are used.

    @since version 1.0.0
    */
    union json_value
    {
        /// object (stored with pointer to save storage)
        object_t* object;
        /// array (stored with pointer to save storage)
        array_t* array;