From 66e3ccc0266e0c21e86cc7dc88bb9010d5bd2ebf Mon Sep 17 00:00:00 2001
From: Dan Spencer <dan@atomicpotato.net>
Date: Mon, 26 Jan 2015 17:38:16 -0700
Subject: [PATCH] Panic with less ambiguous message if render target is already
 borrowed

It's better than seeing 'RefCell<T> already borrowed', in which case
you can't tell _which_ RefCell was borrowed.
---
 src/sdl2/render.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/sdl2/render.rs b/src/sdl2/render.rs
index 08f91268..3844daec 100644
--- a/src/sdl2/render.rs
+++ b/src/sdl2/render.rs
@@ -248,7 +248,10 @@ impl Renderer {
 
     pub fn render_target(&self) -> Option<RefMut<RenderTarget>> {
         if self.render_target_supported() {
-            Some(self.render_target.borrow_mut())
+            match self.render_target.try_borrow_mut() {
+                Some(render_target) => Some(render_target),
+                None => panic!("Render target already borrowed")
+            }
         } else {
             None
         }