Does Clojure actually force you to use those abstractions though? Many languages provide concurrency primitives, but Rust will fail to compile if you try to use non-concurrency safe objects from multiple threads.
The long version is that you could use 'set!' with Vars. But this is very much an avoided practice. Another caveat is that Clojure is hosted (primarily JVM and JS), so any code you call via interop has the characteristics of the host target.
But idiomatic Clojure uses at least Atoms or Refs and even those are discouraged for anything else than storing state, all the algorithmic (transformation, branching and so on) code follows the FP paradigm.
A Rust analogy is the 'unsafe' escape hatch. You can use it but it would be unidiomatic, inconvenient and in most cases unnecessary.
tl;dr: no
Both using 'unsafe' and using String instead of an Enum would compile without runtime guarantees. But such code would stick out.
These markers are irrelevant in a single-threaded scenario.
I’ve googled everywhere but I can’t find a single source of information that completely explains this, possibly showing realistic source code and elaborating the way it could generate memory errors or be miscompiled in case of multiple mutable references.
The TL;DR is: iterator invalidation can happen even without threads.
Another example is if someone tried to use a Vec x inside the closure passed to x.drain.
> doesn’t Rust refuse to compile even when you use non-concurrency safe objects in a single thread?
and given that most types (Vec, HashMap, etc.) aren't "concurrency-safe" (thread-safe?), your answer
> yes
is rather perplexing.