Comment by phire

> whereas a Rust object only has identity if it has a non-zero size.

Rust also has the complication that function pointers are not guaranteed to have an unique identity; If multiple functions compile to the same code, the compiler is allowed de-duplicate them.

The documentation [0] also warns it's also possible for the compiler to create multiple versions of the same function. And while I've absolutely seen the compiler to create multiple optimised versions of functions in disassembled code (partial inlining based on the caller), I'm not sure it's possible to get pointers to more than one version.

[0] https://doc.rust-lang.org/std/ptr/fn.fn_addr_eq.html