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Hate to be a pedant, but that's really not what "zero cost abstractions" means. The idea behind those is that you get a cleaner interface to some gross machine functionality/OS API/etc. layer, but don't pay a performance cost vs. using the gross lower-level layer. E.g. Rust's Option, unlike C++'s std::optional.

What you're thinking of is "no runtime" or "lightweight runtime", which does often mean "no garbage collector".

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Rust's zero cost abstractions mainly stem from its affine ownership model managing memory lifetimes safely and correctly with zero cost - as that is the killer feature... That's what I do.

When people think of "zero cost" they don't think about std::optional. They think about not having to manage memory lifetimes AND NOT having to pay for a Garbage Collector to do it for you. That was always the trade you made until Rust.

I add on some cost to locks to prevent deadlock, and some cost to loops to insert co-operative yields in concurrent contexts unless you turn it off.

> affine ownership

huh? you can rotate and scale the ownership?

Affine as in substructural linear types. They correspond to linear logic [0], and affine logic is named such because the way it's defined corresponds to affine functions. You don't literally need to scale your pointers though.

[0] https://en.wikipedia.org/wiki/Linear_logic

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