rust/rust-error.md

@@ -29,3 +29,15 @@ file_result: Err(IO(Os { code: 21, kind: Other, message: "Is a directory" }))
 ```
 
 `source`属性を付加すると既存のエラーをラップして独自のエラーの中に情報を追加できる
+
+[dtolnay/thiserror: derive\(Error\) for struct and enum error types]( https://github.com/dtolnay/thiserror )
+
+``` rs
+#[derive(Error, Debug)]
+pub enum MyError {
+    ...
+
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),  // source and Display delegate to anyhow::Error
+}
+```
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