is_empty and is_stateless don't work with inaccessible destructors

[cskludev@…]

The following code:

struct Indestructible { private:

~Indestructible() {}

};

bool isEmpty = boost::is_empty<Indestructible>::value; bool isStateless = boost::is_stateless<Indestructible>::value;

generates the following errors (on MSVC2008):

warning C4624: 'boost::detail::empty_helper_t1<T>' : destructor could not be generated because a base class destructor is inaccessible

This does compile on gcc (3.4.5 using MinGW).

[Steven Watanabe]

That isn't an error. It's a warning.

[John Maddock]

(In [60525]) Fixes #4000.