Force #to_liquid call in InputIterator#each

lib/liquid/extensions.rb

@@ -60,3 +60,9 @@ class NilClass
     self
   end
 end
+
+class Proc
+  def to_liquid # :nodoc:
+    self
+  end
+end

lib/liquid/standardfilters.rb

@@ -398,7 +398,7 @@ module Liquid
 
       def each
         @input.each do |e|
-          yield(e.respond_to?(:to_liquid) ? e.to_liquid : e)
+          yield(e.to_liquid)
         end
       end
     end