There are so many more differences between C and C++. Templates, RAII, type inference, lambdas, etc. These are the abstractions that try to be zero cost; C has

There are so many more differences between C and C++. Templates, RAII, type inference, lambdas, etc. These are the abstractions that try to be zero cost; C has little abstraction overall so it doesn't claim "zero cost abstraction". I don't think you need to be fully OOP to claim to be a C++ successor, but you definitely need to have decent zero cost abstractions, including a form of templates/generics. Having RAII might also be a requirement.