From 574e0de431aef23534f80813af3a5fb3ade312b3 Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Thu, 14 Nov 2024 15:32:00 +0000
Subject: [PATCH 1/3] report type name on borrow failure

---
 src/world/mod.rs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/world/mod.rs b/src/world/mod.rs
index e78e7a9..95c4bae 100644
--- a/src/world/mod.rs
+++ b/src/world/mod.rs
@@ -476,9 +476,14 @@ impl World {
         T: Resource,
     {
         let res_id = ResourceId::new::<T>();
-
-        self.resources.get(&res_id).map(|r| FetchMut {
-            inner: AtomicRefMut::map(r.borrow_mut(), Box::as_mut),
+        let resource = self.resources.get(&res_id)?;
+
+        let borrowed_res = match resource.try_borrow_mut() {
+            Ok(v) => v,
+            Err(e) => panic!("{}: {e}", std::any::type_name::<T>())
+        };
+        Some(FetchMut {
+            inner: AtomicRefMut::map(borrowed_res, Box::as_mut),
             phantom: PhantomData,
         })
     }

From 99ab04b73f34308389845cdbb666ed34692d3c80 Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Thu, 14 Nov 2024 15:38:38 +0000
Subject: [PATCH 2/3] same for immutable borrow

---
 src/world/mod.rs | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/world/mod.rs b/src/world/mod.rs
index 95c4bae..ce47a41 100644
--- a/src/world/mod.rs
+++ b/src/world/mod.rs
@@ -426,9 +426,15 @@ impl World {
         T: Resource,
     {
         let res_id = ResourceId::new::<T>();
+        let resource = self.resources.get(&res_id)?;
 
-        self.resources.get(&res_id).map(|r| Fetch {
-            inner: AtomicRef::map(r.borrow(), Box::as_ref),
+        let borrow = match resource.try_borrow() {
+            Ok(res) => res,
+            Err(e) => panic!("{}: {e}", std::any::type_name::<T>())
+        };
+
+        Some(Fetch {
+            inner: AtomicRef::map(borrow, Box::as_ref),
             phantom: PhantomData,
         })
     }

From 1d4e24f91c574b3e89244b469c6c5de75ef01a94 Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Fri, 28 Feb 2025 12:24:28 +0000
Subject: [PATCH 3/3] fix tests

---
 src/world/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/world/mod.rs b/src/world/mod.rs
index ce47a41..12724c9 100644
--- a/src/world/mod.rs
+++ b/src/world/mod.rs
@@ -735,7 +735,7 @@ mod tests {
 
     #[allow(unused)]
     #[test]
-    #[should_panic(expected = "already immutably borrowed")]
+    #[should_panic(expected = "shred::world::tests::Res: already borrowed")]
     fn read_write_fails() {
         let mut world = World::empty();
         world.insert(Res);