What is often meant by that is "This is a zero run-time cost abstraction". That's a very different thing from a zero cost abstraction. Even if the abstraction

What is often meant by that is "This is a zero run-time cost abstraction". That's a very different thing from a zero cost abstraction. Even if the abstraction actually has a zero run-time cost, which is absolutely not a give, it still has a compile-time cost and a human-time cost. See for example: https://www.youtube.com/watch?v=rHIkrotSwcc https://www.youtube.com/watch?v=rHIkrotSwcc