diff --git a/lib/liquid/tokenizer.rb b/lib/liquid/tokenizer.rb
index dcd001f8..e7fb3b53 100644
--- a/lib/liquid/tokenizer.rb
+++ b/lib/liquid/tokenizer.rb
@@ -92,6 +92,7 @@ module Liquid
       end
 
       @ss = nil
+      @source = nil
     end
 
     def shift_normal