Detecting if a class type (which may or may not have a defaultconstructor) is abstract

[BCS]

Reply to Jarrett,

> I just don't think it's possible.  If all classes had default ctors,
> it'd be easy; is(typeof(new T)) would be false if and only if T were
> abstract.  But since that's not the case, I can't think of a way to
> generically see if a given class type is abstract.  Any ideas?
> 
> It's always a little frustrating when doing type introspection and
> having to rely on weird side-effects and properties of types, when the
> compiler is just keeping it in some flag or field somewhere.  Sigh.
> "is(T == abstract)"?  :P
> 

_traits(isAbstractClass, Class) // 2.0 only IIRC