Diamond shaped class structure with a covariant return method causes GCC to fail to adjust base pointers. In the attached program, the output is a huge number instead of the expected 123.
Looking at what happens in GDB, it appears that the this pointer in the call of A(const A &other) gets a B reference rather than an A reference. The place where it expects to find the member A::a is actually outside of the object of type F. If I'm reading the output from GDB correctly. -- Summary: Diamond virtual inheritence with covariant return type confuses GCC Product: gcc Version: 4.4.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: goeran at uddeborg dot se http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43120