Adding upstream version 1.66.0+dfsg1.upstream/1.66.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/library/alloc/src/boxed/thin.rs b/library/alloc/src/boxed/thin.rs
index 649ccfcaa..c477c4490 100644
--- a/library/alloc/src/boxed/thin.rs
+++ b/library/alloc/src/boxed/thin.rs
@@ -2,6 +2,7 @@
 // https://github.com/matthieu-m/rfc2580/blob/b58d1d3cba0d4b5e859d3617ea2d0943aaa31329/examples/thin.rs
 // by matthieu-m
 use crate::alloc::{self, Layout, LayoutError};
+use core::error::Error;
 use core::fmt::{self, Debug, Display, Formatter};
 use core::marker::PhantomData;
 #[cfg(not(no_global_oom_handling))]
@@ -271,3 +272,10 @@ impl<H> WithHeader<H> {
         Layout::new::<H>().extend(value_layout)
     }
 }
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T: ?Sized + Error> Error for ThinBox<T> {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        self.deref().source()
+    }
+}