Considering Go is the only language with a garbage collector out of the three languages you mentioned, I'm not sure how you reach the conclusion they're all as close to the metal.

C and Rust both have predictable memory behaviour, Go does not.

When I read the article it was very clear, due to the compiler's in-memory graphs, that they needed a GC.

(IE, as opposed to reference counting, where if you have cyclic loops, you need to manually go in and "break" the loop so memory gets reclaimed.)

> When I read the article it was very clear, due to the compiler's in-memory graphs, that they needed a GC.

It's actually pretty easy to do something like this with C, just using something like an arena allocator, or honestly, leaking memory. I actually wrote a little allocator yesterday that just dumps memory into a linkedlist, it's not very complicated: http://github.com/danieltuveson/dsalloc/

You allocate wherever you want, and when you're done with the big messy memory graph, you throw it all out at once.

There are obviously a lot of other reasons to choose go over C, though (easier to learn, nicer tooling, memory safety, etc).

I get the impression they'd use smart pointers (C++) or Rc/Arc (Rust)

Go isn't that bad in terms of memory predictability to be honest. It generally has roughly 100% overhead in terms of memory usage compared to no GC. This can be reduced by using GOGC env variable, at the cost of worse performance if not careful.