[boost] is_enum implementation, why add_reference ?

From: Grégory Pakosz (gpakosz_at_[hidden])
Date: 2007-04-17 04:11:17

Hello,

I'm currently having a look at boost's type traits implementation.
At the moment, I'm curious about is_enum. Can please someone explain me 
why add_reference is applied before testing convertibility to 
int_convertible ???

Trying to find more information about how to detect enum types, I only 
found this reference 
http://groups.google.com/group/comp.lang.c++.moderated/browse_thread/thread/898b98475c804f5b/0e6e68dd917ff1fb?hl=en& 
where it's explained that "An enum is a user-defined type that is 
convertible to int without an user-defined conversion (and two 
user-defined conversions in a row are illegal, so you can detect that)."

Thank you.
Regards,
Gregory.