Merge pull request #134 from dtolnay/nonstatic

Support non-static lifetime inside error(transparent)

src/aserror.rs

@@ -1,33 +1,33 @@
 use std::error::Error;
 
-pub trait AsDynError {
-    fn as_dyn_error(&self) -> &(dyn Error + 'static);
+pub trait AsDynError<'a> {
+    fn as_dyn_error(&self) -> &(dyn Error + 'a);
 }
 
-impl<T: Error + 'static> AsDynError for T {
+impl<'a, T: Error + 'a> AsDynError<'a> for T {
     #[inline]
-    fn as_dyn_error(&self) -> &(dyn Error + 'static) {
+    fn as_dyn_error(&self) -> &(dyn Error + 'a) {
         self
     }
 }
 
-impl AsDynError for dyn Error + 'static {
+impl<'a> AsDynError<'a> for dyn Error + 'a {
     #[inline]
-    fn as_dyn_error(&self) -> &(dyn Error + 'static) {
+    fn as_dyn_error(&self) -> &(dyn Error + 'a) {
         self
     }
 }
 
-impl AsDynError for dyn Error + Send + 'static {
+impl<'a> AsDynError<'a> for dyn Error + Send + 'a {
     #[inline]
-    fn as_dyn_error(&self) -> &(dyn Error + 'static) {
+    fn as_dyn_error(&self) -> &(dyn Error + 'a) {
         self
     }
 }
 
-impl AsDynError for dyn Error + Send + Sync + 'static {
+impl<'a> AsDynError<'a> for dyn Error + Send + Sync + 'a {
     #[inline]
-    fn as_dyn_error(&self) -> &(dyn Error + 'static) {
+    fn as_dyn_error(&self) -> &(dyn Error + 'a) {
         self
     }
 }

tests/test_transparent.rs

@@ -57,3 +57,24 @@ fn test_anyhow() {
     assert_eq!("outer", error.to_string());
     assert_eq!("inner", error.source().unwrap().to_string());
 }
+
+#[test]
+fn test_non_static() {
+    #[derive(Error, Debug)]
+    #[error(transparent)]
+    struct Error<'a> {
+        inner: ErrorKind<'a>,
+    }
+
+    #[derive(Error, Debug)]
+    enum ErrorKind<'a> {
+        #[error("unexpected token: {:?}", token)]
+        Unexpected { token: &'a str },
+    }
+
+    let error = Error {
+        inner: ErrorKind::Unexpected { token: "error" },
+    };
+    assert_eq!("unexpected token: \"error\"", error.to_string());
+    assert!(error.source().is_none());
+}