From cc01d3f59aedfa6acefc82660e52d615f3165df5 Mon Sep 17 00:00:00 2001
From: Xu Cheng <xucheng@me.com>
Date: Wed, 6 Jul 2016 16:18:24 +0800
Subject: [PATCH] doctor: fix undefined method `include?' for nil:NilClass

Closes https://github.com/Homebrew/homebrew-core/issues/2758
---
 Library/Homebrew/extend/os/mac/diagnostic.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Library/Homebrew/extend/os/mac/diagnostic.rb b/Library/Homebrew/extend/os/mac/diagnostic.rb
index 00a297d34b..25b451e9f0 100644
--- a/Library/Homebrew/extend/os/mac/diagnostic.rb
+++ b/Library/Homebrew/extend/os/mac/diagnostic.rb
@@ -314,6 +314,7 @@ module Homebrew
       end
 
       def check_for_beta_xquartz
+        return unless MacOS::XQuartz.version
         return unless MacOS::XQuartz.version.include? "beta"
 
         <<-EOS.undent