From 1fbb9d035ddd0c9ae56a91167fda2f100c3987ad Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Fri, 13 Jul 2012 18:43:47 -0700
Subject: [PATCH] improve failure message when key is not present

---
 src/libstd/map.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/libstd/map.rs b/src/libstd/map.rs
index bce843224d1f..90ca5e233720 100644
--- a/src/libstd/map.rs
+++ b/src/libstd/map.rs
@@ -237,7 +237,10 @@ mod chained {
         }
 
         fn get(k: K) -> V {
-            self.find(k).expect(~"Key not found in table")
+            alt self.find(k) {
+              some(v) => {v}
+              none => {fail #fmt["Key not found in table: %?", k]}
+            }
         }
 
         fn [](k: K) -> V {