diff --git a/indexer/feature_decl.hpp b/indexer/feature_decl.hpp
index 4de877b396..333c8ae1dc 100644
--- a/indexer/feature_decl.hpp
+++ b/indexer/feature_decl.hpp
@@ -7,7 +7,7 @@
 
 namespace feature
 {
-enum class GeomType
+enum class GeomType : int8_t
 {
   Undefined = -1,
   Point = 0,