diff --git a/include/mapnik/expression_evaluator.hpp b/include/mapnik/expression_evaluator.hpp
index 5da143a1d..1008be4ee 100644
--- a/include/mapnik/expression_evaluator.hpp
+++ b/include/mapnik/expression_evaluator.hpp
@@ -57,9 +57,9 @@ struct evaluate : boost::static_visitor<T1>
         return attr.value<value_type,feature_type>(feature_);
     }
 
-    value_type operator() (geometry_type_attribute const& attr) const
+    value_type operator() (geometry_type_attribute const& geom) const
     {
-        return attr.value<value_type,feature_type>(feature_);
+        return geom.value<value_type,feature_type>(feature_);
     }
 
     value_type operator() (binary_node<tags::logical_and> const & x) const