PHPStan: don't remember possibly-impure function return values

I don't think we get much benefit from this, and the assumption that functions with a return value are pure is sketchy.
In any case, it's better to avoid these repeated calls anyway.

phpstan.neon.dist

@@ -19,6 +19,7 @@ rules:
 parameters:
 	level: 9
 	checkMissingCallableSignature: true
+	rememberPossiblyImpureFunctionValues: false #risky to remember these, better for performance to avoid repeated calls anyway
 	treatPhpDocTypesAsCertain: false
 	bootstrapFiles:
 		- tests/phpstan/bootstrap.php

src/entity/projectile/Projectile.php

@@ -290,10 +290,11 @@ abstract class Projectile extends Entity{
 		$damage = $this->getResultDamage();
 
 		if($damage >= 0){
-			if($this->getOwningEntity() === null){
+			$owner = $this->getOwningEntity();
+			if($owner === null){
 				$ev = new EntityDamageByEntityEvent($this, $entityHit, EntityDamageEvent::CAUSE_PROJECTILE, $damage);
 			}else{
-				$ev = new EntityDamageByChildEntityEvent($this->getOwningEntity(), $this, $entityHit, EntityDamageEvent::CAUSE_PROJECTILE, $damage);
+				$ev = new EntityDamageByChildEntityEvent($owner, $this, $entityHit, EntityDamageEvent::CAUSE_PROJECTILE, $damage);
 			}
 
 			$entityHit->attack($ev);

src/permission/BanEntry.php

@@ -101,11 +101,12 @@ class BanEntry{
 	}
 
 	public function getString() : string{
+		$expires = $this->getExpires();
 		return implode("|", [
 			$this->getName(),
 			$this->getCreated()->format(self::$format),
 			$this->getSource(),
-			$this->getExpires() === null ? "Forever" : $this->getExpires()->format(self::$format),
+			$expires === null ? "Forever" : $expires->format(self::$format),
 			$this->getReason()
 		]);
 	}