Some review comments.

src/ngraph/op.hpp

@@ -97,7 +97,7 @@ namespace ngraph
         /// Name of the builtin op, for debugging and logging.
         virtual std::string op_name() const = 0;
 
-        // TODO: Implement for each op
+        // TODO: Implement for each op. This enables graphs to be built for now.
         virtual void propagate_types() override {}
 
     protected:

src/ngraph/ops/constant.hpp

@@ -56,8 +56,7 @@ namespace ngraph
         template <typename U>
         static std::shared_ptr<ScalarConstantOp<T>> make(U value)
         {
-            return std::make_shared<ScalarConstantOp<T>>(
-                static_cast<ScalarConstantOp<T>::ctype>(value));
+            return std::make_shared<ScalarConstantOp<T>>(value);
         }
 
     protected: