From f1e71a5b41a0622c21952d23ddeba6f3d9025881 Mon Sep 17 00:00:00 2001
From: Ellen <supbscripter@gmail.com>
Date: Sat, 25 Sep 2021 00:34:02 +0100
Subject: [PATCH] arrr caught ya caller

awd
---
 compiler/rustc_data_structures/src/steal.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_data_structures/src/steal.rs b/compiler/rustc_data_structures/src/steal.rs
index 30f659c2f71b..a1ffbae8b15f 100644
--- a/compiler/rustc_data_structures/src/steal.rs
+++ b/compiler/rustc_data_structures/src/steal.rs
@@ -33,10 +33,11 @@ impl<T> Steal<T> {
 
     #[track_caller]
     pub fn borrow(&self) -> MappedReadGuard<'_, T> {
-        ReadGuard::map(self.value.borrow(), |opt| match *opt {
-            None => panic!("attempted to read from stolen value"),
-            Some(ref v) => v,
-        })
+        let borrow = self.value.borrow();
+        if let None = &*borrow {
+            panic!("attempted to read from stolen value: {}", std::any::type_name::<T>());
+        }
+        ReadGuard::map(borrow, |opt| opt.as_ref().unwrap())
     }
 
     #[track_caller]