diff --git a/lib/puppet/parser/functions/versioncmp.rb b/lib/puppet/parser/functions/versioncmp.rb
index 62df38ffc..2120851e3 100644
--- a/lib/puppet/parser/functions/versioncmp.rb
+++ b/lib/puppet/parser/functions/versioncmp.rb
@@ -1,10 +1,10 @@
 require 'puppet/util/package'
 
-Puppet::Parser::Functions::newfunction(:versioncmp,  :doc => "Compares two versions.") do |args|
+Puppet::Parser::Functions::newfunction(:versioncmp, :type => :rvalue, :doc => "Compares two versions.") do |args|
 
     unless args.length == 2
         raise Puppet::ParseError, "versioncmp should have 2 arguments"
     end
 
     return Puppet::Util::Package.versioncmp(args[0], args[1])
 end