10 use super::Vec;
12 /// A draining iterator for `Vec<T>`.
14 /// This `struct` is created by [`Vec::drain`].
20 /// let mut v = vec![0, 1, 2];
21 /// let iter: std::vec::Drain<'_, _> = v.drain(..);
35     pub(super) vec: NonNull<Vec<T, A>>,  field
51     /// let mut vec = vec!['a', 'b', 'c'];
52     /// let mut drain = vec.drain(..);
68         unsafe { self.vec.as_ref().allocator() }  in allocator()
71     /// Keep unyielded elements in the source `Vec`.
78     /// let mut vec = vec!['a', 'b', 'c'];
79     /// let mut drain = vec.drain(..);
83     /// // This call keeps 'b' and 'c' in the vec.
87     /// // `vec` would be empty.
88     /// assert_eq!(vec, ['b', 'c']);
102         // 3. Update length of the original vec to `len(head) + len(unyielded) + len(tail)`  in keep_rest()
108             let source_vec = this.vec.as_mut();  in keep_rest()
178         /// Moves back the un-`Drain`ed elements to restore the original `Vec`.  in drop()
185                         let source_vec = self.0.vec.as_mut();  in drop()
203         let mut vec = self.vec;  in drop()  localVariable
207 …   // this can be achieved by manipulating the Vec length instead of moving values out from `iter`.  in drop()
209                 let vec = vec.as_mut();  in drop()  localVariable
210                 let old_len = vec.len();  in drop()
211                 vec.set_len(old_len + drop_len + self.tail_len);  in drop()
212                 vec.truncate(old_len + self.tail_len);  in drop()
226         // it also gets touched by vec::Splice which may turn it into a dangling pointer  in drop()
227         // which would make it and the vec pointer point to different allocations which would  in drop()
234             // it from the original vec but also avoid creating a &mut to the front since that could  in drop()
236             let vec_ptr = vec.as_mut().as_mut_ptr();  in drop()