Why Enum's HasFlag method need boxing?

Question

I am reading \"C# via CLR\" and on page 380, there\'s a note saying the following:

Note The Enum class defines a HasFlag method defined as follows

Answer 1

There are two boxing operations involved in this call, not just one. And both are required for one simple reason: Enum.HasFlag() needs type information, not just values, for both this and flag.

Most of the time, an enum value truly is just a set of bits and the compiler has all the type information it needs from the enum types represented in the method signature.

However, in the case of Enum.HasFlags() the very first thing it does is call this.GetType() and flag.GetType() and make sure they're identical. If you wanted the typeless version, you'd be asking if ((attribute & flag) != 0), instead of calling Enum.HasFlags().