From d2fb2fb2a5f58839eda54e5f347e0959ed6eec7c Mon Sep 17 00:00:00 2001
From: Corey Farwell <coreyf@rwell.org>
Date: Tue, 10 Jul 2018 22:25:38 -0400
Subject: [PATCH] Avoid unwrapping in PanicInfo doc example.

Fixes https://github.com/rust-lang/rust/issues/51768.
---
 src/libcore/panic.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/libcore/panic.rs b/src/libcore/panic.rs
index 1b4129b99fc..10f02ca2fdc 100644
--- a/src/libcore/panic.rs
+++ b/src/libcore/panic.rs
@@ -30,7 +30,11 @@
 /// use std::panic;
 ///
 /// panic::set_hook(Box::new(|panic_info| {
-///     println!("panic occurred: {:?}", panic_info.payload().downcast_ref::<&str>().unwrap());
+///     if let Some(s) = panic_info.payload().downcast_ref::<&str>() {
+///         println!("panic occurred: {:?}", s);
+///     } else {
+///         println!("panic occurred");
+///     }
 /// }));
 ///
 /// panic!("Normal panic");
-- 
2.44.0