Merge from rustc

Author: RalfJung

tests/pass-dep/shims/libc-fs-with-isolation.rs

@@ -22,7 +22,8 @@ fn main() {
     }
 
     // test `stat`
-    assert_eq!(fs::metadata("foo.txt").unwrap_err().kind(), ErrorKind::PermissionDenied);
+    let err = fs::metadata("foo.txt").unwrap_err();
+    assert_eq!(err.kind(), ErrorKind::PermissionDenied);
     // check that it is the right kind of `PermissionDenied`
-    assert_eq!(Error::last_os_error().raw_os_error(), Some(libc::EACCES));
+    assert_eq!(err.raw_os_error(), Some(libc::EACCES));
 }