That would require an effects system[0] like Koka's[1]. Then one could not only express the absence of panics but also allocations, infinite loops and various other undesirable effects within some call-trees. This is a desirable feature, but an enormous undertaking.

Absent that there are hacks like no_panic[2]

[0] https://blog.yoshuawuyts.com/extending-rusts-effect-system/ [1] https://koka-lang.github.io/koka/doc/book.html#why-effects [2] https://crates.io/crates/no-panic