diff --git a/src/pocketmine/block/Anvil.php b/src/pocketmine/block/Anvil.php
index f5a017a24..23ad43911 100644
--- a/src/pocketmine/block/Anvil.php
+++ b/src/pocketmine/block/Anvil.php
@@ -85,7 +85,7 @@ class Anvil extends Transparent implements Fallable{
 		return true;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = Facing::rotateY($player->getHorizontalFacing(), true);
 		}
diff --git a/src/pocketmine/block/BaseRail.php b/src/pocketmine/block/BaseRail.php
index ba9913d45..3dfb543ed 100644
--- a/src/pocketmine/block/BaseRail.php
+++ b/src/pocketmine/block/BaseRail.php
@@ -103,7 +103,7 @@ abstract class BaseRail extends Flowable{
 		return 0.7;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(!$blockReplace->getSide(Facing::DOWN)->isTransparent()){
 			$this->tryReconnect();
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Bed.php b/src/pocketmine/block/Bed.php
index 25fe96582..ef02373d9 100644
--- a/src/pocketmine/block/Bed.php
+++ b/src/pocketmine/block/Bed.php
@@ -174,7 +174,7 @@ class Bed extends Transparent{
 
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$this->color = DyeColor::fromMagicNumber($item->getDamage()); //TODO: replace this with a proper colour getter
 		$down = $this->getSide(Facing::DOWN);
 		if(!$down->isTransparent()){
diff --git a/src/pocketmine/block/Block.php b/src/pocketmine/block/Block.php
index 875ca491f..249502fce 100644
--- a/src/pocketmine/block/Block.php
+++ b/src/pocketmine/block/Block.php
@@ -61,7 +61,7 @@ class Block extends Position implements BlockIds, Metadatable{
 	 *
 	 * @return Block
 	 */
-	public static function get(int $id, int $meta = 0, Position $pos = null) : Block{
+	public static function get(int $id, int $meta = 0, ?Position $pos = null) : Block{
 		return BlockFactory::get($id, $meta, $pos);
 	}
 
@@ -233,7 +233,7 @@ class Block extends Position implements BlockIds, Metadatable{
 	 *
 	 * @return bool
 	 */
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		return $this->getLevel()->setBlock($blockReplace, $this);
 	}
 
@@ -301,7 +301,7 @@ class Block extends Position implements BlockIds, Metadatable{
 	 *
 	 * @return bool
 	 */
-	public function onBreak(Item $item, Player $player = null) : bool{
+	public function onBreak(Item $item, ?Player $player = null) : bool{
 		if(($t = $this->level->getTile($this)) !== null){
 			$t->onBlockDestroyed();
 		}
diff --git a/src/pocketmine/block/BlockFactory.php b/src/pocketmine/block/BlockFactory.php
index 3448741ae..6731ac073 100644
--- a/src/pocketmine/block/BlockFactory.php
+++ b/src/pocketmine/block/BlockFactory.php
@@ -590,7 +590,7 @@ class BlockFactory{
 	 *
 	 * @return Block
 	 */
-	public static function get(int $id, int $meta = 0, Position $pos = null) : Block{
+	public static function get(int $id, int $meta = 0, ?Position $pos = null) : Block{
 		if($meta < 0 or $meta > 0xf){
 			throw new \InvalidArgumentException("Block meta value $meta is out of bounds");
 		}
diff --git a/src/pocketmine/block/Button.php b/src/pocketmine/block/Button.php
index cc5086e87..1ff248414 100644
--- a/src/pocketmine/block/Button.php
+++ b/src/pocketmine/block/Button.php
@@ -51,7 +51,7 @@ abstract class Button extends Flowable{
 		return 0b1111;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		//TODO: check valid target block
 		$this->facing = $face;
 		return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Cactus.php b/src/pocketmine/block/Cactus.php
index ec8b51400..dcf965520 100644
--- a/src/pocketmine/block/Cactus.php
+++ b/src/pocketmine/block/Cactus.php
@@ -113,7 +113,7 @@ class Cactus extends Transparent{
 		}
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() === self::SAND or $down->getId() === self::CACTUS){
 			foreach(Facing::HORIZONTAL as $side){
diff --git a/src/pocketmine/block/Cake.php b/src/pocketmine/block/Cake.php
index d18073243..335f0f644 100644
--- a/src/pocketmine/block/Cake.php
+++ b/src/pocketmine/block/Cake.php
@@ -61,7 +61,7 @@ class Cake extends Transparent implements FoodSource{
 			->trim(Facing::WEST, $this->bites / 8);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() !== self::AIR){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Carpet.php b/src/pocketmine/block/Carpet.php
index bc8efe52c..bf2974af8 100644
--- a/src/pocketmine/block/Carpet.php
+++ b/src/pocketmine/block/Carpet.php
@@ -43,7 +43,7 @@ class Carpet extends Flowable{
 		return AxisAlignedBB::one()->trim(Facing::UP, 15 / 16);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() !== self::AIR){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Chest.php b/src/pocketmine/block/Chest.php
index 14e27f7c5..757e67c3d 100644
--- a/src/pocketmine/block/Chest.php
+++ b/src/pocketmine/block/Chest.php
@@ -61,7 +61,7 @@ class Chest extends Transparent{
 		return AxisAlignedBB::one()->contract(0.025, 0, 0.025)->trim(Facing::UP, 0.05);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
diff --git a/src/pocketmine/block/CocoaBlock.php b/src/pocketmine/block/CocoaBlock.php
index fca8c5078..0046d27aa 100644
--- a/src/pocketmine/block/CocoaBlock.php
+++ b/src/pocketmine/block/CocoaBlock.php
@@ -76,7 +76,7 @@ class CocoaBlock extends Transparent{
 			->trim($this->facing, (11 - $this->age * 2) / 16); //outward face
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(Facing::axis($face) !== Facing::AXIS_Y and $blockClicked instanceof Wood and $blockClicked->getTreeType() === TreeType::JUNGLE()){
 			$this->facing = $face;
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Crops.php b/src/pocketmine/block/Crops.php
index 50eb5aad4..2586d9109 100644
--- a/src/pocketmine/block/Crops.php
+++ b/src/pocketmine/block/Crops.php
@@ -48,7 +48,7 @@ abstract class Crops extends Flowable{
 		return 0b111;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($blockReplace->getSide(Facing::DOWN)->getId() === Block::FARMLAND){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
 		}
diff --git a/src/pocketmine/block/Dandelion.php b/src/pocketmine/block/Dandelion.php
index dba08c717..410d98073 100644
--- a/src/pocketmine/block/Dandelion.php
+++ b/src/pocketmine/block/Dandelion.php
@@ -31,7 +31,7 @@ use pocketmine\Player;
 class Dandelion extends Flowable{
 
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() === Block::GRASS or $down->getId() === Block::DIRT or $down->getId() === Block::FARMLAND){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/DeadBush.php b/src/pocketmine/block/DeadBush.php
index b1167f639..0ca036fcd 100644
--- a/src/pocketmine/block/DeadBush.php
+++ b/src/pocketmine/block/DeadBush.php
@@ -32,7 +32,7 @@ use function mt_rand;
 
 class DeadBush extends Flowable{
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(!$this->getSide(Facing::DOWN)->isTransparent()){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
 		}
diff --git a/src/pocketmine/block/Door.php b/src/pocketmine/block/Door.php
index 15ad3518a..39e56e5f8 100644
--- a/src/pocketmine/block/Door.php
+++ b/src/pocketmine/block/Door.php
@@ -103,7 +103,7 @@ abstract class Door extends Transparent{
 		}
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($face === Facing::UP){
 			$blockUp = $this->getSide(Facing::UP);
 			$blockDown = $this->getSide(Facing::DOWN);
diff --git a/src/pocketmine/block/DoublePlant.php b/src/pocketmine/block/DoublePlant.php
index 30ecab275..a9dd48ee0 100644
--- a/src/pocketmine/block/DoublePlant.php
+++ b/src/pocketmine/block/DoublePlant.php
@@ -47,7 +47,7 @@ class DoublePlant extends Flowable{
 		return 0b1000;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$id = $blockReplace->getSide(Facing::DOWN)->getId();
 		if(($id === Block::GRASS or $id === Block::DIRT) and $blockReplace->getSide(Facing::UP)->canBeReplaced()){
 			$top = clone $this;
diff --git a/src/pocketmine/block/EndPortalFrame.php b/src/pocketmine/block/EndPortalFrame.php
index 8f59f1ff3..aebdc7b47 100644
--- a/src/pocketmine/block/EndPortalFrame.php
+++ b/src/pocketmine/block/EndPortalFrame.php
@@ -71,7 +71,7 @@ class EndPortalFrame extends Solid{
 		return AxisAlignedBB::one()->trim(Facing::UP, 3 / 16);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
diff --git a/src/pocketmine/block/EndRod.php b/src/pocketmine/block/EndRod.php
index f83133705..129081538 100644
--- a/src/pocketmine/block/EndRod.php
+++ b/src/pocketmine/block/EndRod.php
@@ -54,7 +54,7 @@ class EndRod extends Flowable{
 		return 0b111;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$this->facing = $face;
 		if($blockClicked instanceof EndRod and $blockClicked->facing === $this->facing){
 			$this->facing = Facing::opposite($face);
diff --git a/src/pocketmine/block/FenceGate.php b/src/pocketmine/block/FenceGate.php
index a146b7251..b26152064 100644
--- a/src/pocketmine/block/FenceGate.php
+++ b/src/pocketmine/block/FenceGate.php
@@ -78,7 +78,7 @@ class FenceGate extends Transparent{
 		);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = $player->getHorizontalFacing();
 		}
diff --git a/src/pocketmine/block/Flower.php b/src/pocketmine/block/Flower.php
index 8ab6d0b93..a8465af39 100644
--- a/src/pocketmine/block/Flower.php
+++ b/src/pocketmine/block/Flower.php
@@ -41,7 +41,7 @@ class Flower extends Flowable{
 	public const TYPE_CORNFLOWER = 9;
 	public const TYPE_LILY_OF_THE_VALLEY = 10;
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() === Block::GRASS or $down->getId() === Block::DIRT or $down->getId() === Block::FARMLAND){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/FlowerPot.php b/src/pocketmine/block/FlowerPot.php
index a8af03df7..057827e65 100644
--- a/src/pocketmine/block/FlowerPot.php
+++ b/src/pocketmine/block/FlowerPot.php
@@ -51,7 +51,7 @@ class FlowerPot extends Flowable{
 		return AxisAlignedBB::one()->contract(3 / 16, 0, 3 / 16)->trim(Facing::UP, 5 / 8);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($this->getSide(Facing::DOWN)->isTransparent()){
 			return false;
 		}
diff --git a/src/pocketmine/block/Furnace.php b/src/pocketmine/block/Furnace.php
index 780771eae..a407aa75d 100644
--- a/src/pocketmine/block/Furnace.php
+++ b/src/pocketmine/block/Furnace.php
@@ -87,7 +87,7 @@ class Furnace extends Solid{
 		return $this;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
diff --git a/src/pocketmine/block/GlazedTerracotta.php b/src/pocketmine/block/GlazedTerracotta.php
index 83244b556..a3f4957ba 100644
--- a/src/pocketmine/block/GlazedTerracotta.php
+++ b/src/pocketmine/block/GlazedTerracotta.php
@@ -60,7 +60,7 @@ class GlazedTerracotta extends Solid{
 		return TieredTool::TIER_WOODEN;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
diff --git a/src/pocketmine/block/Ice.php b/src/pocketmine/block/Ice.php
index ccd3e72d8..2bbacded1 100644
--- a/src/pocketmine/block/Ice.php
+++ b/src/pocketmine/block/Ice.php
@@ -45,7 +45,7 @@ class Ice extends Transparent{
 		return BlockToolType::TYPE_PICKAXE;
 	}
 
-	public function onBreak(Item $item, Player $player = null) : bool{
+	public function onBreak(Item $item, ?Player $player = null) : bool{
 		if(($player === null or $player->isSurvival()) and !$item->hasEnchantment(Enchantment::SILK_TOUCH())){
 			return $this->getLevel()->setBlock($this, BlockFactory::get(Block::WATER));
 		}
diff --git a/src/pocketmine/block/ItemFrame.php b/src/pocketmine/block/ItemFrame.php
index 1f65296f1..1c862fb0b 100644
--- a/src/pocketmine/block/ItemFrame.php
+++ b/src/pocketmine/block/ItemFrame.php
@@ -70,7 +70,7 @@ class ItemFrame extends Flowable{
 		}
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($face === Facing::DOWN or $face === Facing::UP or !$blockClicked->isSolid()){
 			return false;
 		}
diff --git a/src/pocketmine/block/Ladder.php b/src/pocketmine/block/Ladder.php
index c7af4a453..e5589279e 100644
--- a/src/pocketmine/block/Ladder.php
+++ b/src/pocketmine/block/Ladder.php
@@ -74,7 +74,7 @@ class Ladder extends Transparent{
 	}
 
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(!$blockClicked->isTransparent() and Facing::axis($face) !== Facing::AXIS_Y){
 			$this->facing = $face;
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Leaves.php b/src/pocketmine/block/Leaves.php
index a61bacce7..563f378e3 100644
--- a/src/pocketmine/block/Leaves.php
+++ b/src/pocketmine/block/Leaves.php
@@ -120,7 +120,7 @@ class Leaves extends Transparent{
 		}
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$this->noDecay = true; //artificial leaves don't decay
 		return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
 	}
diff --git a/src/pocketmine/block/Lever.php b/src/pocketmine/block/Lever.php
index ce88e9bed..458fb8932 100644
--- a/src/pocketmine/block/Lever.php
+++ b/src/pocketmine/block/Lever.php
@@ -77,7 +77,7 @@ class Lever extends Flowable{
 		return 0.5;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(!$blockClicked->isSolid()){
 			return false;
 		}
diff --git a/src/pocketmine/block/NetherWartPlant.php b/src/pocketmine/block/NetherWartPlant.php
index 60775f882..fb2f9cb5e 100644
--- a/src/pocketmine/block/NetherWartPlant.php
+++ b/src/pocketmine/block/NetherWartPlant.php
@@ -49,7 +49,7 @@ class NetherWartPlant extends Flowable{
 		return 0b11;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() === Block::SOUL_SAND){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Pumpkin.php b/src/pocketmine/block/Pumpkin.php
index d0abc3653..0f760987f 100644
--- a/src/pocketmine/block/Pumpkin.php
+++ b/src/pocketmine/block/Pumpkin.php
@@ -55,7 +55,7 @@ class Pumpkin extends Solid{
 		return BlockToolType::TYPE_AXE;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
diff --git a/src/pocketmine/block/RedMushroom.php b/src/pocketmine/block/RedMushroom.php
index 8f23f1c48..35f832da6 100644
--- a/src/pocketmine/block/RedMushroom.php
+++ b/src/pocketmine/block/RedMushroom.php
@@ -40,7 +40,7 @@ class RedMushroom extends Flowable{
 		}
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if(!$down->isTransparent()){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/RedstoneOre.php b/src/pocketmine/block/RedstoneOre.php
index c5f13c09f..3ab072028 100644
--- a/src/pocketmine/block/RedstoneOre.php
+++ b/src/pocketmine/block/RedstoneOre.php
@@ -71,7 +71,7 @@ class RedstoneOre extends Solid{
 		return $this->lit ? 9 : 0;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		return $this->getLevel()->setBlock($this, $this, false);
 	}
 
diff --git a/src/pocketmine/block/RedstoneRepeater.php b/src/pocketmine/block/RedstoneRepeater.php
index 160703cdc..ab16eead2 100644
--- a/src/pocketmine/block/RedstoneRepeater.php
+++ b/src/pocketmine/block/RedstoneRepeater.php
@@ -82,7 +82,7 @@ class RedstoneRepeater extends Flowable{
 		return $this;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(!$blockReplace->getSide(Facing::DOWN)->isTransparent()){
 			if($player !== null){
 				$this->facing = Facing::opposite($player->getHorizontalFacing());
diff --git a/src/pocketmine/block/Sapling.php b/src/pocketmine/block/Sapling.php
index e6d789be6..0b725ffab 100644
--- a/src/pocketmine/block/Sapling.php
+++ b/src/pocketmine/block/Sapling.php
@@ -57,7 +57,7 @@ class Sapling extends Flowable{
 		return 0b1000;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() === self::GRASS or $down->getId() === self::DIRT or $down->getId() === self::FARMLAND){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/SignPost.php b/src/pocketmine/block/SignPost.php
index e8a196865..1470fea51 100644
--- a/src/pocketmine/block/SignPost.php
+++ b/src/pocketmine/block/SignPost.php
@@ -59,7 +59,7 @@ class SignPost extends Transparent{
 		return null;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($face !== Facing::DOWN){
 
 			if($face === Facing::UP){
diff --git a/src/pocketmine/block/Skull.php b/src/pocketmine/block/Skull.php
index 37d88cdd5..78df03dc6 100644
--- a/src/pocketmine/block/Skull.php
+++ b/src/pocketmine/block/Skull.php
@@ -82,7 +82,7 @@ class Skull extends Flowable{
 		return AxisAlignedBB::one()->contract(0.25, 0, 0.25)->trim(Facing::UP, 0.5);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($face === Facing::DOWN){
 			return false;
 		}
diff --git a/src/pocketmine/block/Slab.php b/src/pocketmine/block/Slab.php
index e1de5a78e..75e3b6c7e 100644
--- a/src/pocketmine/block/Slab.php
+++ b/src/pocketmine/block/Slab.php
@@ -104,7 +104,7 @@ abstract class Slab extends Transparent{
 		return false;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		/* note these conditions can't be merged, since one targets clicked and the other replace */
 
 		if($blockClicked instanceof Slab and $blockClicked->slabType !== SlabType::DOUBLE() and $blockClicked->isSameType($this) and (
diff --git a/src/pocketmine/block/SnowLayer.php b/src/pocketmine/block/SnowLayer.php
index 617ef79c7..e80b18cf8 100644
--- a/src/pocketmine/block/SnowLayer.php
+++ b/src/pocketmine/block/SnowLayer.php
@@ -75,7 +75,7 @@ class SnowLayer extends Flowable implements Fallable{
 		return AxisAlignedBB::one()->trim(Facing::UP, $this->layers >= 4 ? 0.5 : 1);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($blockReplace instanceof SnowLayer){
 			if($blockReplace->layers >= 8){
 				return false;
diff --git a/src/pocketmine/block/Stair.php b/src/pocketmine/block/Stair.php
index 2af550a0f..a66ef1d11 100644
--- a/src/pocketmine/block/Stair.php
+++ b/src/pocketmine/block/Stair.php
@@ -106,7 +106,7 @@ abstract class Stair extends Transparent{
 		) ? $side->facing : null;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = $player->getHorizontalFacing();
 		}
diff --git a/src/pocketmine/block/StandingBanner.php b/src/pocketmine/block/StandingBanner.php
index aa2bf1735..e20490fbb 100644
--- a/src/pocketmine/block/StandingBanner.php
+++ b/src/pocketmine/block/StandingBanner.php
@@ -62,7 +62,7 @@ class StandingBanner extends Transparent{
 		return null;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($face !== Facing::DOWN){
 			if($face === Facing::UP and $player !== null){
 				$this->rotation = ((int) floor((($player->yaw + 180) * 16 / 360) + 0.5)) & 0x0f;
diff --git a/src/pocketmine/block/Sugarcane.php b/src/pocketmine/block/Sugarcane.php
index 2b1bc5862..6a0281213 100644
--- a/src/pocketmine/block/Sugarcane.php
+++ b/src/pocketmine/block/Sugarcane.php
@@ -106,7 +106,7 @@ class Sugarcane extends Flowable{
 		}
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN);
 		if($down->getId() === self::SUGARCANE_BLOCK){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/TallGrass.php b/src/pocketmine/block/TallGrass.php
index 43e8f685d..688a4a47e 100644
--- a/src/pocketmine/block/TallGrass.php
+++ b/src/pocketmine/block/TallGrass.php
@@ -36,7 +36,7 @@ class TallGrass extends Flowable{
 		return true;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$down = $this->getSide(Facing::DOWN)->getId();
 		if($down === self::GRASS or $down === self::DIRT){
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Torch.php b/src/pocketmine/block/Torch.php
index 46a2036c5..7e076f7c5 100644
--- a/src/pocketmine/block/Torch.php
+++ b/src/pocketmine/block/Torch.php
@@ -59,7 +59,7 @@ class Torch extends Flowable{
 		}
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($blockClicked->canBeReplaced() and !$blockClicked->getSide(Facing::DOWN)->isTransparent()){
 			$this->facing = Facing::UP;
 			return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
diff --git a/src/pocketmine/block/Trapdoor.php b/src/pocketmine/block/Trapdoor.php
index b2c6ddb4f..1cc736894 100644
--- a/src/pocketmine/block/Trapdoor.php
+++ b/src/pocketmine/block/Trapdoor.php
@@ -66,7 +66,7 @@ class Trapdoor extends Transparent{
 		return AxisAlignedBB::one()->trim($this->open ? $this->facing : ($this->top ? Facing::DOWN : Facing::UP), 13 / 16);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($player !== null){
 			$this->facing = Facing::opposite($player->getHorizontalFacing());
 		}
diff --git a/src/pocketmine/block/TripwireHook.php b/src/pocketmine/block/TripwireHook.php
index d35b15bc1..b91887f36 100644
--- a/src/pocketmine/block/TripwireHook.php
+++ b/src/pocketmine/block/TripwireHook.php
@@ -53,7 +53,7 @@ class TripwireHook extends Flowable{
 		return 0b1111;
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(Facing::axis($face) !== Facing::AXIS_Y){
 			//TODO: check face is valid
 			$this->facing = $face;
diff --git a/src/pocketmine/block/Vine.php b/src/pocketmine/block/Vine.php
index a4b671652..27b59636a 100644
--- a/src/pocketmine/block/Vine.php
+++ b/src/pocketmine/block/Vine.php
@@ -143,7 +143,7 @@ class Vine extends Flowable{
 		return [];
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if(!$blockClicked->isSolid() or Facing::axis($face) === Facing::AXIS_Y){
 			return false;
 		}
diff --git a/src/pocketmine/block/WaterLily.php b/src/pocketmine/block/WaterLily.php
index 390891225..9719427b2 100644
--- a/src/pocketmine/block/WaterLily.php
+++ b/src/pocketmine/block/WaterLily.php
@@ -39,7 +39,7 @@ class WaterLily extends Flowable{
 		return AxisAlignedBB::one()->contract(1 / 16, 0, 1 / 16)->trim(Facing::UP, 63 / 64);
 	}
 
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		if($blockClicked instanceof Water){
 			$up = $blockClicked->getSide(Facing::UP);
 			if($up->canBeReplaced()){
diff --git a/src/pocketmine/block/utils/PillarRotationTrait.php b/src/pocketmine/block/utils/PillarRotationTrait.php
index 8b4aa32cb..7113ae764 100644
--- a/src/pocketmine/block/utils/PillarRotationTrait.php
+++ b/src/pocketmine/block/utils/PillarRotationTrait.php
@@ -94,7 +94,7 @@ trait PillarRotationTrait{
 	 *
 	 * @return bool
 	 */
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
 		$this->axis = Facing::axis($face);
 		/** @see Block::place() */
 		return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);