diff --git a/map/booking_filter_availability_params.hpp b/map/booking_filter_availability_params.hpp
index 216f4abd0d..0c1ea8ab3e 100644
--- a/map/booking_filter_availability_params.hpp
+++ b/map/booking_filter_availability_params.hpp
@@ -16,7 +16,6 @@ namespace filter
 namespace availability
 {
 using Results = platform::SafeCallback<void(search::Results const &results)>;
-using ResultsUnsafe = std::function<void(search::Results const &results)>;
 
 struct Params
 {
@@ -26,11 +25,16 @@ struct Params
   Results m_callback;
 };
 
-struct ParamsInternal
+namespace internal
+{
+using ResultsUnsafe = std::function<void(search::Results const &results)>;
+
+struct Params
 {
   AvailabilityParams m_params;
   ResultsUnsafe m_callback;
 };
+}  // namespace internal
 }  // namespace availability
 }  // namespace filter
 }  // namespace booking
diff --git a/search/everywhere_search_callback.hpp b/search/everywhere_search_callback.hpp
index 78346fb43d..a31e5abd02 100644
--- a/search/everywhere_search_callback.hpp
+++ b/search/everywhere_search_callback.hpp
@@ -22,6 +22,8 @@ public:
     virtual bool IsLocalAdsCustomer(Result const & result) const = 0;
   };
 
+  // The signature of the callback should be the same as EverywhereSaerchParams::OnResults, but
+  // EverywhereSaerchParams is located in map project and we do not need dependency.
   using OnResults =
     std::function<void(Results const & results, std::vector<bool> const & isLocalAdsCustomer)>;