Method dealloc

crates/core/src/slab.rs:431–447

(&mut self, id: Id)

    /// deallocate an arbitrary value.
    #[inline]
    pub fn dealloc(&mut self, id: Id) -> T {
        let entry = core::mem::replace(
            self.entries
                .get_mut(id.0.index())
                .expect("id from a different slab"),
            Entry::Free { next_free: None },
        );
        match entry {
            Entry::Free { .. } => panic!("attempt to deallocate an entry that is already vacant"),
            Entry::Occupied(value) => {
                let next_free = core::mem::replace(&mut self.free, Some(id.0));
                self.entries[id.0.index()] = Entry::Free { next_free };
                self.len -= 1;
                value
            }
        }
    }

    /// Iterate over all values currently allocated within this `Slab`.
    ///