diff --git a/lib/mutant/diff.rb b/lib/mutant/diff.rb
index a97a43ea..666bcef2 100644
--- a/lib/mutant/diff.rb
+++ b/lib/mutant/diff.rb
@@ -18,7 +18,7 @@ module Mutant
     # @api private
     #
     def diff
-      return if diffs.length.equal?(0)
+      return if diffs.empty?
 
       minimized_hunks.map do |hunk|
         hunk.diff(:unified) << NEWLINE