From 3c4c9b9ff66e0b9a58aa27aab36bf1465dcc4bfa Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Thu, 12 Jul 2018 18:53:11 +1000
Subject: [PATCH] Fix mistaken mut on boolean_bitfield

---
 src/utils/boolean_bitfield.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/utils/boolean_bitfield.rs b/src/utils/boolean_bitfield.rs
index 92b461981e..77323fe048 100644
--- a/src/utils/boolean_bitfield.rs
+++ b/src/utils/boolean_bitfield.rs
@@ -62,7 +62,7 @@ impl BooleanBitfield {
     }
 
     // Return the total number of bits set to true.
-    pub fn num_true_bits(&mut self) -> u64 {
+    pub fn num_true_bits(&self) -> u64 {
         let mut count: u64 = 0;
         for byte in &self.vec {
             for bit in 0..8 {