I agree that it shouldn't compile, and for 2 separate reasons:

1: A's default constructor cannot access the default constructor for the
member copy_protection - remember that protected access only gives you
access to protected members of bases through pointers, references and
objects of the derived class, not the base class (this is to prevent one
derived class from breaking objects of other derived classes derived
from the same base). As a result, A doesn't have a well-formed default
constructor, so even "A a;" shouldn't compile. This is covered in 11.5/1
of the standard.

Delete the member copy_protection to get around this, and try a
different compiler to get the error in the first place.

2: In the call, "c" is copy initialized from a default constructed A.
The compiler is allowed to optimize out the copy, but according to the
standard it must check that the copy could be made (e.g. that there is
an accessible copy constructor). This is covered in 12.2/1 of the standard.

Again, use a different compiler to get the error.

Should be:

class A : noncopyable // no need for public inheritance
{
};

You may want to report the bugs to MS.

Tom