Index: boost/proto/operators.hpp
===================================================================
--- boost/proto/operators.hpp	(revision 66967)
+++ boost/proto/operators.hpp	(working copy)
@@ -62,6 +62,10 @@
         template<typename Domain, typename Grammar, typename Trait, typename Tag, typename Left, typename Right>
         struct enable_binary
           : boost::lazy_enable_if_c<
+                //Trait::value
+                //lazy_matches<result_of::as_child<Left>, Grammar>::value
+                //lazy_matches<result_of::as_child<Right>, Grammar>::value
+                //lazy_matches<result_of::make_expr<Tag, Domain, Left &, Right &>, Grammar>::value
                 boost::mpl::and_<
                     Trait
                   , lazy_matches<result_of::as_child<Left>, Grammar>
@@ -105,7 +109,7 @@
       , BOOST_PROTO_APPLY_UNARY_(TRAIT, Arg)                                                        \
       , TAG                                                                                         \
       , Arg                                                                                         \
-    >::type const                                                                                   \
+    >::type                                                                                   \
     operator OP(Arg &arg BOOST_PROTO_UNARY_OP_IS_POSTFIX_ ## POST)                                  \
     {                                                                                               \
         return boost::proto::detail::make_expr_<TAG, DOMAIN, Arg &>()(arg);                         \
@@ -118,7 +122,7 @@
       , BOOST_PROTO_APPLY_UNARY_(TRAIT, Arg)                                                        \
       , TAG                                                                                         \
       , Arg const                                                                                   \
-    >::type const                                                                                   \
+    >::type                                                                                         \
     operator OP(Arg const &arg BOOST_PROTO_UNARY_OP_IS_POSTFIX_ ## POST)                            \
     {                                                                                               \
         return boost::proto::detail::make_expr_<TAG, DOMAIN, Arg const &>()(arg);                   \
@@ -134,7 +138,7 @@
       , TAG                                                                                         \
       , Left                                                                                        \
       , Right                                                                                       \
-    >::type const                                                                                   \
+    >::type                                                                                         \
     operator OP(Left &left, Right &right)                                                           \
     {                                                                                               \
         return boost::proto::detail::make_expr_<TAG, DOMAIN, Left &, Right &>()(left, right);       \
@@ -148,7 +152,7 @@
       , TAG                                                                                         \
       , Left                                                                                        \
       , Right const                                                                                 \
-    >::type const                                                                                   \
+    >::type                                                                                         \
     operator OP(Left &left, Right const &right)                                                     \
     {                                                                                               \
         return boost::proto::detail::make_expr_<TAG, DOMAIN, Left &, Right const &>()(left, right); \
@@ -162,7 +166,7 @@
       , TAG                                                                                         \
       , Left const                                                                                  \
       , Right                                                                                       \
-    >::type const                                                                                   \
+    >::type                                                                                         \
     operator OP(Left const &left, Right &right)                                                     \
     {                                                                                               \
         return boost::proto::detail::make_expr_<TAG, DOMAIN, Left const &, Right &>()(left, right); \
@@ -176,7 +180,7 @@
       , TAG                                                                                         \
       , Left const                                                                                  \
       , Right const                                                                                 \
-    >::type const                                                                                   \
+    >::type                                                                                         \
     operator OP(Left const &left, Right const &right)                                               \
     {                                                                                               \
         return boost::proto::detail::make_expr_<TAG, DOMAIN, Left const &, Right const &>()(left, right);\