Pin 与 Unpin

  编译:成功
  运行(退出码 0):
    创建后:data 在 0x16b3426e8,ptr 指向 0x16b3426e8,二者相同: true
    移动后:data 在 0x16b342788,ptr 仍指向 0x16b3426e8,二者相同: false

  编译:成功
  运行(退出码 0):
    Pin<Box<Data>> 被移动了两次,Data 的地址不变: true

  源码:
      1 | use std::{pin::Pin, marker::PhantomPinned};
      2 | struct NoMove { v: u32, _p: PhantomPinned }
      3 | fn main() {
      4 |     let mut p = Box::pin(NoMove { v: 1, _p: PhantomPinned });
      5 |     let r: &mut NoMove = p.as_mut().get_mut();
      6 |     r.v = 2;
      7 | }
  编译:失败
    warning: unused import: `pin::Pin`
     --> <实验目录>/src/u106c.rs:1:11
      |
    1 | use std::{pin::Pin, marker::PhantomPinned};
      |           ^^^^^^^^
      |
      = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
    
    error[E0277]: `PhantomPinned` cannot be unpinned
        --> <实验目录>/src/u106c.rs:5:37
         |
       5 |     let r: &mut NoMove = p.as_mut().get_mut();
         |                                     ^^^^^^^ within `NoMove`, the trait `Unpin` is not implemented for `PhantomPinned`
         |
         = note: consider using the `pin!` macro
                 consider using `Box::pin` if you need to access the pinned value outside of the current scope
    note: required because it appears within the type `NoMove`
        --> <实验目录>/src/u106c.rs:2:8
         |
       2 | struct NoMove { v: u32, _p: PhantomPinned }
         |        ^^^^^^
    note: required by a bound in `Pin::<&'a mut T>::get_mut`
        --> <rust 标准库源码>/library/core/src/pin.rs:1598:12
         |
    1596 |     pub const fn get_mut(self) -> &'a mut T
         |                  ------- required by a bound in this associated function
    1597 |     where
    1598 |         T: Unpin,
         |            ^^^^^ required by this bound in `Pin::<&mut T>::get_mut`
    
    …(共 33 行)
  源码:
      1 | use std::{pin::Pin, marker::PhantomPinned};
      2 | struct NoMove { v: u32, _p: PhantomPinned }
      3 | fn main() { let x = NoMove { v: 1, _p: PhantomPinned }; let p = Pin::new(&x); let _ = p; }
  编译:失败
    error[E0277]: `PhantomPinned` cannot be unpinned
        --> <实验目录>/src/u106d.rs:3:74
         |
       3 | fn main() { let x = NoMove { v: 1, _p: PhantomPinned }; let p = Pin::new(&x); let _ = p; }
         |                                                                 -------- ^^ within `NoMove`, the trait `Unpin` is not implemented for `PhantomPinned`
         |                                                                 |
         |                                                                 required by a bound introduced by this call
         |
         = note: consider using the `pin!` macro
                 consider using `Box::pin` if you need to access the pinned value outside of the current scope
    note: required because it appears within the type `NoMove`
        --> <实验目录>/src/u106d.rs:2:8
         |
       2 | struct NoMove { v: u32, _p: PhantomPinned }
         |        ^^^^^^
    note: required by a bound in `Pin::<Ptr>::new`
        --> <rust 标准库源码>/library/core/src/pin.rs:1159:25
         |
    1159 | impl<Ptr: Deref<Target: Unpin>> Pin<Ptr> {
         |                         ^^^^^ required by this bound in `Pin::<Ptr>::new`
    ...
    1181 |     pub const fn new(pointer: Ptr) -> Pin<Ptr> {
         |                  --- required by a bound in this associated function
    
    error: aborting due to 1 previous error
    
    For more information about this error, try `rustc --explain E0277`.

  i32                              Unpin: ✓
  String                           Unpin: ✓
  Vec<u8>                          Unpin: ✓
  Box<T>                           Unpin: ✓
  &mut i32                         Unpin: ✓
  PhantomPinned                    Unpin: ✗
  含 PhantomPinned 的 struct         Unpin: ✗
  async fn 的 Future(跨 await 借用)    Unpin: ✗
  async 块(无借用)                     Unpin: ✗

  编译:成功;警告:
    warning: unused import: `Poll`
     --> <实验目录>/src/u106f.rs:1:53
      |
    1 | use std::{pin::pin, future::Future, task::{Context, Poll, Waker}};
      |                                                     ^^^^
      |
      = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
    
    warning: 1 warning emitted
  运行(退出码 0):
    poll 栈上固定的 Future: Ready(6)
  编译:成功
  运行(退出码 0):
    x