What is __argvalue?

Question

Also, there is one other thing that is an lvalue in VC#, though it's a language extension - __argvalue().

Source

That was the only Google result for __argvalue.

I tried it in LINQPad and it doesn't seem to exist.

Answer 1

I can definitively state that there is no __argvalue in C# as of .NET Framework 4.0. The compiler binary contains a table of tokens. You can find the other hidden __ prefixed keywords starting at 0x00009840. However, a search of the entire binary shows that there is no __argvalue token.

The author of that comment may have been referring to __arglist, which can be an lvalue.