diff --git a/modules/dnn/CMakeLists.txt b/modules/dnn/CMakeLists.txt
index 62ec379bd..950d7998d 100644
--- a/modules/dnn/CMakeLists.txt
+++ b/modules/dnn/CMakeLists.txt
@@ -9,7 +9,7 @@ if(${PROTOBUF_FOUND} AND EXISTS ${PROTOBUF_PROTOC_EXECUTABLE})
   file(GLOB PROTO_FILES src/*.proto)
   PROTOBUF_GENERATE_CPP(PROTO_HDRS PROTO_SRCS ${PROTO_FILES})
   set(HAVE_PROTOBUF ON)
-  add_definitions(-DHAVE_PROTOBUF 1)
+  add_definitions(-DHAVE_PROTOBUF=1)
 else()
   message(STATUS "PROTOBUF not found. Caffe import function will be disabled.")
   set(HAVE_PROTOBUF OFF)
@@ -19,9 +19,9 @@ endif()
 endmacro(_dnn_find_protobuf)
 
 if(BUILD_opencv_core)#build as OpenCV module
-_dnn_find_protobuf()
 set(the_description "Deep neural network module. It allows to load models and to make forward pass")
 set(OPENCV_MODULE_IS_PART_OF_WORLD OFF)
+_dnn_find_protobuf()
 
 ocv_add_module(dnn opencv_imgproc opencv_core opencv_highgui WRAP python matlab)
 ocv_warnings_disable(CMAKE_CXX_FLAGS -Wno-shadow -Wno-parentheses)
diff --git a/modules/dnn/include/opencv2/dnn/dict.hpp b/modules/dnn/include/opencv2/dnn/dict.hpp
index b44af2501..25a87522f 100644
--- a/modules/dnn/include/opencv2/dnn/dict.hpp
+++ b/modules/dnn/include/opencv2/dnn/dict.hpp
@@ -43,7 +43,7 @@ private:
     void release();
 };
 
-class Dict
+class CV_EXPORTS Dict
 {
     //TODO: maybe this mechanism was realized somewhere in OpenCV?
     typedef std::map<String, DictValue> _Dict;
diff --git a/modules/dnn/src/dnn.cpp b/modules/dnn/src/dnn.cpp
index a67b5319d..3f8b1f20d 100644
--- a/modules/dnn/src/dnn.cpp
+++ b/modules/dnn/src/dnn.cpp
@@ -145,9 +145,8 @@ struct LayerOutId
 struct LayerData
 {
     LayerData() {}
-    LayerData(const String &_name, const String &_type, LayerParams &_params = LayerParams())
-        : name(_name), type(_type), params(_params)
-    {}
+    LayerData(const String &_name, const String &_type, LayerParams &_params)
+        : name(_name), type(_type), params(_params) {}
 
     String name;
     String type;
@@ -179,7 +178,8 @@ struct Net::Impl
 {
     Impl()
     {
-        layers.insert(make_pair(0, LayerData("_input", "_input")));
+        LayerParams paramsEmpty;
+        layers.insert(make_pair(0, LayerData("_input", "_noType", paramsEmpty)));
         lastLayerId = 1;
         netWasAllocated = false;
     }
@@ -218,9 +218,12 @@ struct Net::Impl
         if (v.isString())
             return getLayerId(v.get<String>());
         else if (v.isInt())
-            int id = v.get<int>();
+            return v.get<int>();
         else
+        {
             CV_Assert(v.isString() || v.isInt());
+            return -1;
+        }
     }
 
     LayerData& getLayerData(const DictValue &v)