Multiple inheritance in its many forms (including interfaces as found in Java/C#/Golang) always makes casts interesting, even sometimes when methods aren't involved.

Somewhat related stuff that might be interesting:

dynamic_cast in C++: http://mentorembedded.github.io/cxx-abi/abi.html#rtti

Golang's interface casts (also used by Swift I believe): http://research.swtch.com/interfaces

Speculation for interface casts in Java: https://wiki.openjdk.java.net/display/HotSpot/PerformanceTec...