michaelkuc6/blog_os
1
0
Fork 0
mirror of https://github.com/phil-opp/blog_os.git synced 2025-12-19 15:57:48 +00:00
Code Issues Projects Releases Wiki Activity

Update playground error messages

Browse Source
This commit is contained in:
Thalia Archibald
2025-08-21 18:18:20 -06:00
parent bae61dd786
commit 1ba06fe61c
8 changed files with 23 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
blog/content/edition-2/posts/12-async-await/index.ja.md
View File

@@ -640,21 +640,21 @@ let mut heap_value = Box::pin(SelfReferential {
今、[調整した例を実行してみると](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=961b0db194bbe851ff4d0ed08d3bd98a)、動作しなくなっていることがわかります:
```
error[E0594]: cannot assign to data in a dereference of `std::pin::Pin<std::boxed::Box<SelfReferential>>`
error[E0594]: cannot assign to data in dereference of `Pin<Box<SelfReferential>>`
--> src/main.rs:10:5
|
10 | heap_value.self_ptr = ptr;
| ^^^^^^^^^^^^^^^^^^^^^^^^^ cannot assign
|
= help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `std::pin::Pin<std::boxed::Box<SelfReferential>>`
= help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<Box<SelfReferential>>`
error[E0596]: cannot borrow data in a dereference of `std::pin::Pin<std::boxed::Box<SelfReferential>>` as mutable
error[E0596]: cannot borrow data in dereference of `Pin<Box<SelfReferential>>` as mutable
--> src/main.rs:16:36
|
16 | let stack_value = mem::replace(&mut *heap_value, SelfReferential {
| ^^^^^^^^^^^^^^^^ cannot borrow as mutable
|
= help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `std::pin::Pin<std::boxed::Box<SelfReferential>>`
= help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Pin<Box<SelfReferential>>`
```
どちらのエラーも、`Pin<Box<SelfReferential>>` 型が `DerefMut` trait を実装しなくなったために発生します。これはまさに求めていた結果であり、というのも、`DerefMut` trait は `&mut` 参照を返してしまうからで、私達はこれを防ぎたかったのです。これは、`Unpin` を使用しないようにして、`Box::new` を `Box::pin` に変更したからこそ起こる現象です。