diff -Naur boost_1_50_0_beta1/boost/spirit/home/classic/utility/impl/chset/range_run.ipp boost_1_50_0_beta1_patch/boost/spirit/home/classic/utility/impl/chset/range_run.ipp
--- boost_1_50_0_beta1/boost/spirit/home/classic/utility/impl/chset/range_run.ipp	2008-06-22 20:35:38.000000000 +0530
+++ boost_1_50_0_beta1_patch/boost/spirit/home/classic/utility/impl/chset/range_run.ipp	2012-06-29 11:54:42.000000000 +0530
@@ -91,7 +91,7 @@
 
                 if (iter != run.end() && iter->includes(v))
                     return true;
-                if (iter != run.begin())
+                if (iter != run.end() && iter != run.begin())
                     return (--iter)->includes(v);
             }
             return false;