From a5718ba377fbc915618062d7562229a4eb754c9f Mon Sep 17 00:00:00 2001
From: "Brian J. Burg" <burg@cs.washington.edu>
Date: Thu, 8 Nov 2012 16:25:22 -0800
Subject: [PATCH] Change option::expect to not require a Copy bound, and move
 instead.

---
 src/libcore/option.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index 3b1d2079800..0bb3262e569 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -85,16 +85,17 @@ pub enum Option<T> {
     }
 }
 
-pub pure fn expect<T: Copy>(opt: Option<T>, reason: ~str) -> T {
+pub pure fn expect<T>(opt: Option<T>, reason: ~str) -> T {
     /*!
-     * Gets the value out of an option, printing a specified message on
-     * failure
+     * Gets the value out of an option without copying, printing a 
+     * specified message on failure.
      *
      * # Failure
      *
      * Fails if the value equals `none`
      */
-    match opt { Some(copy x) => x, None => fail reason }
+    if opt.is_some() { move option::unwrap(move opt) }
+    else { fail reason }
 }
 
 pub pure fn map<T, U>(opt: &Option<T>, f: fn(x: &T) -> U) -> Option<U> {