[rust-lang/rust] E0716 without "let's call this" and spurious "requirement introduced here"

### ROOT CAUSE The error E0716 occurs because a temporary value created by `Rc::clone` is dropped too early, while a mutable borrow is still active. The closure `f` requires the value to outlive its borrow, but the temporary value's lifetime is insufficient. ### CODE FIX ```rust // Original problematic code let value = Rc::clone(&map).borrow_mut().entry(self.key.clone()); // Fixed code: Clone the Arc into a variable first let map_clone = Rc::clone(&map); let mut entry = map_clone.borrow_mut().entry(self.key.clone()); // Then use entry or pass it directly if needed f(entry); ``` This change ensures the clone lives long enough for the mutable borrow, resolving the temporary value issue and the spurious lifetime requirement.