From 751658b2be478b70528dfd6f8b506ac7f8d94aee Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Fri, 20 Jul 2018 17:48:51 +1000
Subject: [PATCH] Add saturating sub for deposits

---
 src/state/transition/deposits.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/state/transition/deposits.rs b/src/state/transition/deposits.rs
index fee217615..004dddd00 100644
--- a/src/state/transition/deposits.rs
+++ b/src/state/transition/deposits.rs
@@ -32,7 +32,8 @@ pub fn process_ffg_deposits(
         >= cry_state.total_deposits.saturating_mul(U256::from(2));
     let mut should_finalize = false;
     if should_justify {
-        if cry_state.last_justified_epoch == cry_state.current_epoch - 1 {
+        if cry_state.last_justified_epoch == 
+            cry_state.current_epoch.saturating_sub(1) {
             should_finalize = true;
         }
     }