diff --git a/include/turtle/detail/function.hpp b/include/turtle/detail/function.hpp
index fed3802..e231a95 100644
--- a/include/turtle/detail/function.hpp
+++ b/include/turtle/detail/function.hpp
@@ -30,7 +30,6 @@
 #include <boost/preprocessor/comparison/greater.hpp>
 #include <boost/test/utils/basic_cstring/basic_cstring.hpp>
 #include <boost/test/utils/lazy_ostream.hpp>
-#include <boost/call_traits.hpp>
 #include <boost/optional.hpp>
 #include <ostream>
 #include <vector>
diff --git a/include/turtle/detail/is_functor.hpp b/include/turtle/detail/is_functor.hpp
index ca804b7..0b8f53a 100644
--- a/include/turtle/detail/is_functor.hpp
+++ b/include/turtle/detail/is_functor.hpp
@@ -17,15 +17,13 @@ namespace mock
 {
 namespace detail
 {
-    template< typename F, typename P, class = void >
-    struct is_callable : std::false_type
+    /// Trait to return true if F is a functor that can be called with a single argument Arg
+    template< typename F, typename Arg, class = void >
+    struct is_functor : std::false_type
     {};
-    template< typename F, typename P >
-    struct is_callable< F, P, boost::void_t<decltype( std::declval<F>()( std::declval<P>() ) )> >: std::true_type
+    template< typename F, typename Arg >
+    struct is_functor< F, Arg, boost::void_t<decltype( std::declval<F>()( std::declval<Arg>() ) )> >: std::true_type
     {};
-
-    template< typename T, typename P >
-    using is_functor = is_callable< T, P >;
 }
 } // mock
 
diff --git a/include/turtle/log.hpp b/include/turtle/log.hpp
index b7728d0..06a8928 100644
--- a/include/turtle/log.hpp
+++ b/include/turtle/log.hpp
@@ -13,7 +13,6 @@
 #include "stream.hpp"
 #include "format.hpp"
 #include <boost/detail/container_fwd.hpp>
-#include <boost/function_types/is_callable_builtin.hpp>
 #include <boost/none.hpp>
 #include <memory>
 #include <type_traits>
@@ -51,6 +50,15 @@ namespace detail
             s << (it == begin ? "" : ",") << mock::format( *it );
         s << ')';
     }
+    template<typename T>
+    struct is_callable_impl: std::false_type
+    {};
+    template<typename R, typename... Args>
+    struct is_callable_impl<R(Args...)>: std::true_type
+    {};
+    template<typename T>
+    struct is_callable: is_callable_impl< std::remove_cv_t<T> >
+    {};
 }
 
 #ifdef MOCK_AUTO_PTR
@@ -182,19 +190,13 @@ namespace detail
     }
 
     template< typename T >
-    std::enable_if_t<
-        boost::function_types::is_callable_builtin< T >::value,
-        stream&
-    >
+    std::enable_if_t< detail::is_callable< T >::value, stream& >
     operator<<( stream& s, T* )
     {
         return s << '?';
     }
     template< typename T >
-    std::enable_if_t<
-        !boost::function_types::is_callable_builtin< T >::value,
-        stream&
-    >
+    std::enable_if_t< !detail::is_callable< T >::value, stream& >
     operator<<( stream& s, T* t )
     {
         *s.s_ << t;
diff --git a/test/detail/test_is_functor.cpp b/test/detail/test_is_functor.cpp
index e384f83..6d48a19 100644
--- a/test/detail/test_is_functor.cpp
+++ b/test/detail/test_is_functor.cpp
@@ -28,12 +28,12 @@ namespace
     template< typename T >
     void is_functor( T )
     {
-        static_assert( mock::detail::is_functor< T, int >::value, "Should be functor");
+        static_assert( mock::detail::is_functor< T, int >::value, "Should be a functor taking an int");
     }
     template< typename T >
     void is_not_functor( T )
     {
-        static_assert( !mock::detail::is_functor< T, int >::value, "Should not be a functor" );
+        static_assert( !mock::detail::is_functor< T, int >::value, "Should not be a functor taking an int" );
     }
 
     void f0() {}