--- a/rust/land2d/src/lib.rs	Tue Nov 06 23:45:54 2018 +0300
+++ b/rust/land2d/src/lib.rs	Wed Nov 07 00:02:48 2018 +0300
@@ -122,8 +122,8 @@
     }
 
     pub fn fill(&mut self, start_point: Point, border_value: T, fill_value: T) {
-        debug_assert!(self.is_valid_coordinate(start_point.x - 1, start_point.y));
-        debug_assert!(self.is_valid_coordinate(start_point.x, start_point.y));
+        assert!(self.is_valid_coordinate(start_point.x - 1, start_point.y));
+        assert!(self.is_valid_coordinate(start_point.x, start_point.y));
 
         let mask = self.mask;
         let width = self.width();