Created attachment 404 [details]
program reproducing the bug

non-const Ptr<T>::operator * () returns const reference. 

This cause compilation of the attached program to fail with the following errors:

../scratch/ptr-dereference-and-assign.cc: In function ‘int main(int, char**)’:
../scratch/ptr-dereference-and-assign.cc:38: error: passing ‘const One’ as ‘this’ argument of ‘One& One::operator=(const One&)’ discards qualifiers
../scratch/ptr-dereference-and-assign.cc:48: error: passing ‘const Two’ as ‘this’ argument of ‘Two& Two::operator=(const Two&)’ discards qualifiers