From 199a02cb68b956fbfb1891164541ae51c02a24de Mon Sep 17 00:00:00 2001
From: Erick Tryzelaar <erick.tryzelaar@gmail.com>
Date: Thu, 6 Aug 2015 09:31:37 -0700
Subject: [PATCH] i64::wrapping_neg is not stable yet

---
 serde_json/src/de.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/serde_json/src/de.rs b/serde_json/src/de.rs
index 8dea69e1..04491899 100644
--- a/serde_json/src/de.rs
+++ b/serde_json/src/de.rs
@@ -259,7 +259,9 @@ impl<Iter> Deserializer<Iter>
                 if pos {
                     visitor.visit_u64(res)
                 } else {
-                    let res_i64 = (res as i64).wrapping_neg();
+                    // FIXME: `wrapping_neg` will be stable in Rust 1.2
+                    //let res_i64 = (res as i64).wrapping_neg();
+                    let res_i64 = (!res + 1) as i64;
 
                     // Convert into a float if we underflow.
                     if res_i64 > 0 {