Fix potential access to destroyed variable on stack

AI/BattleAI/AttackPossibility.cpp

@@ -45,11 +45,12 @@ void DamageCache::buildObstacleDamageCache(std::shared_ptr<HypotheticBattle> hb,
 			continue;
 
 		std::unique_ptr<spells::BattleCast> cast = nullptr;
+		std::unique_ptr<spells::ObstacleCasterProxy> caster = nullptr;
 		if(spellObstacle->obstacleType == SpellCreatedObstacle::EObstacleType::SPELL_CREATED)
 		{
 			const auto * hero = hb->battleGetFightingHero(spellObstacle->casterSide);
-			auto caster = spells::ObstacleCasterProxy(hb->getSidePlayer(spellObstacle->casterSide), hero, *spellObstacle);
-			cast = std::make_unique<spells::BattleCast>(spells::BattleCast(hb.get(), &caster, spells::Mode::PASSIVE, obst->getTrigger().toSpell()));
+			caster = std::make_unique<spells::ObstacleCasterProxy>(hb->getSidePlayer(spellObstacle->casterSide), hero, *spellObstacle);
+			cast = std::make_unique<spells::BattleCast>(spells::BattleCast(hb.get(), caster.get(), spells::Mode::PASSIVE, obst->getTrigger().toSpell()));
 		}
 
 		auto affectedHexes = obst->getAffectedTiles();