Visual Studio 2015 UP3 support

dlib/dnn/core.h

@@ -208,6 +208,8 @@ namespace dlib
         };
 
         template <typename T> struct alwaysbool { typedef bool type; };
+        // one more structure for VS 2015 UP3 support workaround
+        template <typename T> struct alwaysbool2 { typedef bool type; };
 
         resizable_tensor& rt();
 
@@ -254,7 +256,7 @@ namespace dlib
         constexpr auto has_inplace_backward(
             layer_type& layer,
             SUBNET& sub
-        ) -> typename alwaysbool<decltype(layer.backward(rt(),rt(),sub,rt()))>::type
+        ) -> typename alwaysbool2<decltype(layer.backward(rt(),rt(),sub,rt()))>::type
         {
             return false;
         }
@@ -263,7 +265,7 @@ namespace dlib
         constexpr auto has_inplace_backward(
             layer_type& layer,
             SUBNET& sub
-        ) -> typename alwaysbool<decltype(layer.backward(rt(),sub,rt()))>::type
+        ) -> typename alwaysbool2<decltype(layer.backward(rt(),sub,rt()))>::type
         {
             return false;
         }
@@ -272,7 +274,7 @@ namespace dlib
         constexpr auto has_inplace_backward(
             layer_type& layer,
             SUBNET& sub
-        ) -> typename alwaysbool<decltype(layer.backward_inplace(rt(),rt(),sub.get_gradient_input(),rt()))>::type
+        ) -> typename alwaysbool2<decltype(layer.backward_inplace(rt(),rt(),sub.get_gradient_input(),rt()))>::type
         {
             return true;
         }
@@ -281,7 +283,7 @@ namespace dlib
         constexpr auto has_inplace_backward(
             layer_type& layer,
             SUBNET& sub
-        ) -> typename alwaysbool<decltype(layer.backward_inplace(rt(),sub.get_gradient_input(),rt()))>::type
+        ) -> typename alwaysbool2<decltype(layer.backward_inplace(rt(),sub.get_gradient_input(),rt()))>::type
         {
             return true;
         }
@@ -290,7 +292,7 @@ namespace dlib
         constexpr auto is_inplace_layer(
             layer_type& layer,
             const SUBNET& sub 
-        ) -> typename alwaysbool<decltype(layer.forward(sub,rt()))>::type
+        ) -> typename alwaysbool2<decltype(layer.forward(sub,rt()))>::type
         {
             return false;
         }

dlib/use_cpp_11.cmake

@@ -61,7 +61,6 @@ else()
        ";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";cxx_delegating_constructors;" AND
        ";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";cxx_thread_local;" AND
        ";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";cxx_constexpr;" AND
-       ";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";cxx_decltype_incomplete_return_types;" AND
        ";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";cxx_auto_type;")
 
       set(COMPILER_CAN_DO_CPP_11 1)