Rollup merge of rust-lang#58963 - seanmonstar:patch-3, r=cramertj

pietroalbini · web-flow · commit 378a0118f36f · 2019-03-08T09:42:10.000+01:00
libstd: implement Error::source for io::Error
diff --git a/src/libstd/io/error.rs b/src/libstd/io/error.rs
@@ -556,6 +556,14 @@ impl error::Error for Error {
             Repr::Custom(ref c) => c.error.cause(),
         }
     }
+
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Simple(..) => None,
+            Repr::Custom(ref c) => c.error.source(),
+        }
+    }
 }
 
 fn _assert_error_is_sync_send() {

Original file line number	Diff line number	Diff line change
`@@ -556,6 +556,14 @@ impl error::Error for Error {`
`556`	`556`	`Repr::Custom(ref c) => c.error.cause(),`
`557`	`557`	`}`
`558`	`558`	`}`
	`559`	`+`
	`560`	`+ fn source(&self) -> Option<&(dyn error::Error + 'static)> {`
	`561`	`+ match self.repr {`
	`562`	`+ Repr::Os(..) => None,`
	`563`	`+ Repr::Simple(..) => None,`
	`564`	`+ Repr::Custom(ref c) => c.error.source(),`
	`565`	`+ }`
	`566`	`+ }`
`559`	`567`	`}`
`560`	`568`
`561`	`569`	`fn _assert_error_is_sync_send() {`