Ref counting is also no GC by the definition of a GC I was brought up with.

But yes, I was also thinking about the borrow checker.

Not necessarily in Rust, as other languages start to adopt similar techniques.

Maybe not how you were brought up, and people argue... But Watson & Watson, back in '87, described ref counting as "An efficient garbage collection scheme for parallel computer architectures".

Even the dragon book refers to ref counting as a form of garbage collection.

Line 2 of Ref counting's Wikipedia page refers to garbage collection.

People have argued since the invention in 1960, but... Ref counting is one form of GC. [0] It might not be a tracing GC, but it is GC.

[0] https://dl.acm.org/doi/10.1145/367487.367501

As refcounting and tracing are the two primary starting points for garbage collection, they're its two pillars so to speak (e.g. https://web.eecs.umich.edu/~weimerw/2012-4610/reading/bacon-...), I don't know of any serious person in the memory management space who doesn't see refcounting as a GC, although some languages with a refcounting GC say "they don't have a GC" in their marketing material.

As a general rule, tracing seeks to optimise for throughput while refcounting seeks to optimise for footprint, although the two can become more elaborate and converge (as shown in the paper I linked).

Then somehow someone has taught you badly, any proper CS reference book in academia has it, like the famous GC Handbook,

https://gchandbook.org/

The other languages adopting such type systems, also keep automatic resource management around for productivity.

The ones that don't, are still in the looking for meaningful adoption stage.

Most academic definitions of garbage collection include reference counting. It’s just a form of it.

https://gchandbook.org/contents.html