Fix explicit instantiation regression

include/boost/smart_ptr/shared_ptr.hpp

@@ -655,7 +655,7 @@ public:
         BOOST_ASSERT( px != 0 );
         BOOST_ASSERT( i >= 0 && ( i < boost::detail::sp_extent< T >::value || boost::detail::sp_extent< T >::value == 0 ) );
 
-        return px[ i ];
+        return static_cast< typename boost::detail::sp_array_access< T >::type >( px[ i ] );
     }
 
     element_type * get() const BOOST_NOEXCEPT

test/Jamfile.v2

@@ -171,5 +171,7 @@ import testing ;
 
           [ run weak_from_raw_test.cpp ]
           [ run weak_from_raw_test2.cpp ]
+
+          [ compile sp_explicit_inst_test.cpp ]
         ;
 }

test/array_fail_array_access.cpp

@@ -12,8 +12,12 @@ struct X
 {
 };
 
+template<class T> void f( T & /*t*/ )
+{
+}
+
 int main()
 {
     boost::shared_ptr<X> px( new X );
-    px[ 0 ];
+    f( px[ 0 ] );
 }

test/sp_explicit_inst_test.cpp

@@ -0,0 +1,23 @@
+//
+// Explicit instantiations are reported to exist in user code
+//
+// Copyright (c) 2014 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//
+
+#include <boost/shared_ptr.hpp>
+
+template class boost::shared_ptr< int >;
+
+struct X
+{
+};
+
+template class boost::shared_ptr< X >;
+
+int main()
+{
+}