Index: boost/gil/gil_concept.hpp
===================================================================
--- boost/gil/gil_concept.hpp	(revision 81326)
+++ boost/gil/gil_concept.hpp	(working copy)
@@ -254,6 +254,10 @@
     // accessor/modifier of the value of each axis.
     template <size_t K> const typename axis<K>::type& T::axis_value() const;
     template <size_t K>       typename axis<K>::type& T::axis_value();
+
+    // subscript operator support for getting an lvalue reference to the appropriate axis
+    value_type& T::operator[](size_t) const;
+    value_type& T::operator[](size_t);
 };
 \endcode
 */
@@ -272,8 +276,10 @@
         LT lt=axis_value<N-1>(point);
         axis_value<N-1>(point)=lt;
     
-        value_type v=point[0];  ignore_unused_variable_warning(v);
-        point[0]=point[0];
+        value_type v=point[0];
+        point[0]=v;
+        const P& p=point;
+        p[0]=v;
     }
     P point;
 };
@@ -456,11 +462,12 @@
     template <typename T>
     struct ChannelIsMutableConcept {
         void constraints() {
-            c=c;
+            c1=c2;
             using std::swap;
-            swap(c,c);
+            swap(c1,c2);
         }
-        T c;
+        T c1;
+        T c2;
     };
 }
 
@@ -951,9 +958,10 @@
     void constraints() {
         gil_function_requires<HomogeneousPixelConcept<P> >();
         gil_function_requires<MutableHomogeneousColorBaseConcept<P> >();
-        p[0]=p[0];
+        p[0]=v;
     }
     P p;
+    typename P::template element_type<P>::type v;
 };
 
 /// \brief Pixel concept that is a Regular type
Index: libs/gil/test/pixel_iterator.cpp
===================================================================
--- libs/gil/test/pixel_iterator.cpp	(revision 81326)
+++ libs/gil/test/pixel_iterator.cpp	(working copy)
@@ -147,14 +147,14 @@
     unsigned char v8 = get_color( p8, gray_color_t() );
 
 	// all values should be 110b ( 6 );
-    //assert( v1 == 6 );
-    //assert( v2 == 6 );
-    //assert( v3 == 6 );
-    //assert( v4 == 6 );
-    //assert( v5 == 6 );
-    //assert( v6 == 6 );
-    //assert( v7 == 6 );
-    //assert( v8 == 6 );
+    assert( v1 == 6 );
+    assert( v2 == 6 );
+    assert( v3 == 6 );
+    assert( v4 == 6 );
+    assert( v5 == 6 );
+    assert( v6 == 6 );
+    assert( v7 == 6 );
+    assert( v8 == 6 );
 }
 
 // TODO: Make better tests. Use some code from below.