diagnostic refers to the wrong object's lifetime

[spookyvision]

Code

use std::{any::Any, cell::RefCell, rc::Rc};

fn doit(it: &dyn Any) {
    if let Some(s) = it.downcast_ref::<&str>() {
        println!("{s}");
    }
}
fn main() {
    // this works fine:
    let s = Rc::new(RefCell::new("hello, inner!"));
    let inner: &str = &s.borrow();
    doit(&inner as &dyn Any);
    // the commented line at the bottom doesn't compile:
    // `s` dropped here while still borrowed
    //
    // but it seems the real issue is not the lifetime of `s` but the
    // intermediate `Ref` created by `borrow()` that gets dropped too early.
    //
    //doit(&s.borrow() as &dyn Any);
}

Current output

error[E0597]: `s` does not live long enough
(...)
`s` dropped here while still borrowed

Desired output

casting Ref<'_, &'static str> to &dyn Any requires that `s` is borrowed for 'static

Rationale and extra context

the lifetime of s isn't the problem - it's the implicit temporary Ref object that does not live long enough

Other cases

No response

Rust Version

rustc 1.79.0 (129f3b996 2024-06-10)
binary: rustc
commit-hash: 129f3b9964af4d4a709d1383930ade12dfe7c081
commit-date: 2024-06-10
host: aarch64-apple-darwin
release: 1.79.0
LLVM version: 18.1.7

Anything else?

thanks to @Dirbaio for both figuring out the actual problem and suggesting the improved diagnostic!