diff --git a/ortools/constraint_solver/csharp/constraint_solver.i b/ortools/constraint_solver/csharp/constraint_solver.i
index e9da28f602..4ab4587268 100644
--- a/ortools/constraint_solver/csharp/constraint_solver.i
+++ b/ortools/constraint_solver/csharp/constraint_solver.i
@@ -28,7 +28,7 @@ using System.Collections.Generic;
 %include "std_string.i"
 
 %include "ortools/base/base.i"
-%include "ortools/util/csharp/vector.i"
+%import "ortools/util/csharp/vector.i"
 %include "ortools/util/csharp/proto.i"
 
 // We need to forward-declare the proto here, so that PROTO_INPUT involving it