From 627b75d945a482f4062ab6a58fc4f660a9e62128 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Tue, 11 Jan 2011 11:45:39 -0800
Subject: [PATCH] System superclass check can be done prior to instantiating

This also fixes a 1.8.7 incompatibility.
---
 lib/vagrant/vm.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/vagrant/vm.rb b/lib/vagrant/vm.rb
index ff29c6dcc..691f35361 100644
--- a/lib/vagrant/vm.rb
+++ b/lib/vagrant/vm.rb
@@ -53,8 +53,8 @@ module Vagrant
       system ||= env.config.vm.system
 
       if system.is_a?(Class)
+        raise Errors::VMSystemError, :_key => :invalid_class, :system => system.to_s if !(system <= Systems::Base)
         @system = system.new(self)
-        raise Errors::VMSystemError, :_key => :invalid_class, :system => system.to_s if !@system.is_a?(Systems::Base)
       elsif system.is_a?(Symbol)
         # Hard-coded internal systems
         mapping = {