it is done

core/src/mindustry/entities/traits/SpawnerTrait.java

@@ -0,0 +1,18 @@
+package mindustry.entities.traits;
+
+import arc.math.geom.Position;
+import mindustry.entities.type.*;
+import mindustry.world.Tile;
+
+public interface SpawnerTrait extends TargetTrait, Position{
+    Tile getTile();
+
+    void updateSpawning(Player unit);
+
+    boolean hasUnit(Unit unit);
+
+    @Override
+    default boolean isValid(){
+        return getTile().entity instanceof SpawnerTrait;
+    }
+}