[Boost-users] [concept_check] Why does char not qualify as "Integer"?

The statement BOOST_CONCEPT_ASSERT((boost::Integer<T>)); triggers an error if T is the type char. It does not trigger an error if T is either of type signed char or unsigned char. I can understand why it's not so easy to detect for SignedInteger or UnsignedInteger given type char, but to my understanding using type char should work with the above statement. Peter