I know, the meaning of "zero cost abstraction" is really "zero cost to not use the abstraction."
But that's like saying if you don't use rust you don't pay for it. Just because there is the unsafe escape hatch in the language, you don't get to label the language as zero cost abstraction. Because practically speaking there is a lot more runtime cost to rust than people will tell you.
Many langauges (almost anything without a runtime) meet that definition of zero cost abstraction then.
But that's like saying if you don't use rust you don't pay for it. Just because there is the unsafe escape hatch in the language, you don't get to label the language as zero cost abstraction. Because practically speaking there is a lot more runtime cost to rust than people will tell you.
Many langauges (almost anything without a runtime) meet that definition of zero cost abstraction then.