Hi,
This is the simplest possible repro I could get:
#include
class A {};
class B : private A {};
typedef boost::variant variant_t;
int main()
{
B b;
variant_t v (b);
}
This used to work with Boost 1.59.0 but fails with 1.64.0
Using wandbox I've found that:
- it started failing in 1.62.0
- clang does not have this problem
- newer and older versions of gcc do have the same problem
The error is miles long. I think the important parts are:
boost/type_traits/is_convertible.hpp:149:53: error: 'A' is an inaccessible
base of 'B'
error: no matching function for call to 'boost::variant::variant(B&)'
It seems the metaprogramming messes up due to the private inheritance, and
decides that the variant is *not* constructible from B
Workarounds are very welcome!
Switching to C++14 is not an option (yet).
Regards
