Ugh, I remember seeing null `this` values used on purpose in some old Windows MFC program, or maybe it was COM... I imagine the author was an old-school C prog

Ugh, I remember seeing null `this` values used on purpose in some old Windows MFC program, or maybe it was COM... I imagine the author was an old-school C programmer who understood well how the C++ object veneer maps down to equivalent C code / assembly. From that perspective, dealing with null `this` pointers is just another way to get the compiler to spit out the assembly instructions you want, and maybe enables some elegant patterns in client code... but it's exactly the kind of thing that makes newcomers hate C++.