Only allow attacking adjacent locations for rats

Author: erasedbird

engine/src/main/battlecode/world/RobotControllerImpl.java

@@ -950,6 +950,10 @@ private void assertCanAttackRat(MapLocation loc, int cheeseConsumed) throws Game
         assertIsActionReady();
         // Attack is limited to vision radius
         assertCanActLocation(loc, this.getType().getVisionRadiusSquared());
+        if (!this.getLocation().isAdjacentTo(loc)) {
+            throw new GameActionException(CANT_DO_THAT, "Rats can only attack adjacent squares!");
+        }
+
         if (!this.gameWorld.isPassable(loc))
             throw new GameActionException(CANT_DO_THAT, "Rats cannot attack squares with walls or dirt on them!");