What's the difference between subtyping and inheritance?
See the following discussions in other stack exchange groups.

See discussion in https://stackoverflow.com/questions/23592131/what-is-the-difference-between-subtyping-and-inheritance-in-oo-programming

Also see https://cstheory.stackexchange.com/questions/10620/how-does-inheritance-differ-from-subtyping 

However there is some differences of opinion. See Inheritance Is Subtyping as well as Inheritance Is Not Subtyping