Build: Enable -Wimplicit-fallthrough on clang (#25056)

* Misc: Use [[fallthrough]] attribute instead of comment to mark intentional fallthroughs

Related: #25006

* Misc: Add some missing breaks (no-ops) to satisfy clang

Related: #25006
Closes #25055

* Build: Enable -Wimplicit-fallthrough on clang

Closes #25006

src/server/game/Conditions/ConditionMgr.cpp

@@ -3474,6 +3474,7 @@ int32 EvalSingleValue(ByteBuffer& buffer, Player const* player)
                 return 0;
 
             value = WorldStateExpressionFunctions[functionType](player, arg1, arg2);
+            break;
         }
         default:
             break;

src/server/game/Entities/Player/Player.cpp

@@ -12750,6 +12750,7 @@ void Player::DestroyItem(uint8 bag, uint8 slot, bool update)
                     case EQUIPMENT_SLOT_MAINHAND:
                     case EQUIPMENT_SLOT_OFFHAND:
                         RecalculateRating(CR_ARMOR_PENETRATION);
+                        break;
                     default:
                         break;
                 }
@@ -21105,6 +21106,7 @@ void Player::_SaveInventory(CharacterDatabaseTransaction& trans)
                 stmt = CharacterDatabase.GetPreparedStatement(CHAR_DEL_CHAR_INVENTORY_BY_ITEM);
                 stmt->setUInt64(0, item->GetGUID().GetCounter());
                 trans->Append(stmt);
+                break;
             case ITEM_UNCHANGED:
                 break;
         }
@@ -26645,6 +26647,7 @@ void Player::_LoadSkills(PreparedQueryResult result)
                     break;
                 case SKILL_RANGE_LEVEL:
                     max = GetMaxSkillValueForLevel();
+                    break;
                 default:
                     break;
             }

src/server/game/Entities/Unit/Unit.cpp

@@ -11697,6 +11697,7 @@ uint32 Unit::GetModelForForm(ShapeshiftForm form, uint32 spellId) const
             {
                 if (HasAura(58135)) // Glyph of Spectral Wolf
                     return 60247;
+                break;
             }
             default:
                 break;

src/server/game/Handlers/GroupHandler.cpp

@@ -562,6 +562,7 @@ void WorldSession::HandleSetPartyAssignment(WorldPackets::Party::SetPartyAssignm
         case GROUP_ASSIGN_MAINTANK:
             group->RemoveUniqueGroupMemberFlag(MEMBER_FLAG_MAINTANK);           // Remove main assist flag from current if any.
             group->SetGroupMemberFlag(packet.Target, packet.Set, MEMBER_FLAG_MAINTANK);
+            break;
         default:
             break;
     }

src/server/game/Maps/Map.cpp

@@ -3241,6 +3241,7 @@ size_t Map::DespawnAll(SpawnObjectType type, ObjectGuid::LowType spawnId)
         case SPAWN_TYPE_GAMEOBJECT:
             for (auto const& pair : Trinity::Containers::MapEqualRange(GetGameObjectBySpawnIdStore(), spawnId))
                 toUnload.push_back(pair.second);
+            break;
         default:
             break;
     }

src/server/game/Spells/Spell.cpp

@@ -8616,6 +8616,7 @@ bool WorldObjectSpellTargetCheck::operator()(WorldObject* target) const
             case TARGET_OBJECT_TYPE_CORPSE_ENEMY:
                 if (unitTarget->IsAlive())
                     return false;
+                break;
             default:
                 break;
         }

src/server/game/Spells/SpellEffects.cpp

@@ -1540,6 +1540,7 @@ void Spell::SendLoot(ObjectGuid guid, LootType loottype)
                     gameObjTarget->TriggeringLinkedGameObject(trapEntry, player);
 
                 // Don't return, let loots been taken
+                break;
             default:
                 break;
         }

src/server/game/Spells/SpellInfo.cpp

@@ -4455,7 +4455,8 @@ bool _isPositiveEffectImpl(SpellInfo const* spellInfo, SpellEffectInfo const& ef
                 if (otherEffect.EffectIndex != effect.EffectIndex && // for spells like 38044: instakill effect is negative but auras on target must count as buff
                     otherEffect.TargetA.GetTarget() == effect.TargetA.GetTarget() &&
                     otherEffect.TargetB.GetTarget() == effect.TargetB.GetTarget())
-                return false;
+                    return false;
+                break;
             default:
                 break;
         }

src/server/scripts/Battlefield/BattlefieldWG.cpp

@@ -773,6 +773,7 @@ void BattlefieldWG::DoCompleteOrIncrementAchievement(uint32 achievement, Player*
         case ACHIEVEMENTS_WIN_WG_100:
         {
             // player->UpdateCriteria();
+            break;
         }
         default:
         {

src/server/scripts/EasternKingdoms/BlackrockMountain/BlackrockSpire/instance_blackrock_spire.cpp

@@ -303,6 +303,7 @@ public:
                     for (GuidList::const_iterator itr = _incarceratorList.begin(); itr != _incarceratorList.end(); ++itr)
                         if (Creature* creature = instance->GetCreature(*itr))
                             creature->Respawn();
+                    break;
                 default:
                     break;
             }

src/server/scripts/EasternKingdoms/MagistersTerrace/instance_magisters_terrace.cpp

@@ -126,6 +126,7 @@ class instance_magisters_terrace : public InstanceMapScript
                     case NPC_SUNBLADE_BLOOD_KNIGHT:
                         if (creature->GetDistance(KaelthasTrashGroupDistanceComparisonPos) < 10.0f)
                             _kaelthasPreTrashGUIDs.insert(creature->GetGUID());
+                        break;
                     default:
                         break;
                 }

src/server/scripts/EasternKingdoms/ScarletMonastery/boss_high_inquisitor_fairbanks.cpp

@@ -146,6 +146,7 @@ struct boss_high_inquisitor_fairbanks : public BossAI
                 if (Unit* target = SelectTarget(SelectTargetMethod::MaxThreat, 0, 30.f, true, false))
                     DoCast(target, SPELL_SLEEP);
                 events.Repeat(30s);
+                break;
             default:
                 break;
         }

src/server/scripts/Kalimdor/CavernsOfTime/CullingOfStratholme/npc_arthas.cpp

@@ -1485,6 +1485,7 @@ public:
                             chromie->AI()->Talk(RP5_LINE_CHROMIE0);
                             chromie->AddNpcFlag(NPCFlags(UNIT_NPC_FLAG_GOSSIP | UNIT_NPC_FLAG_QUESTGIVER));
                         }
+                        break;
                     default:
                         break;
                 }

src/server/scripts/Kalimdor/zone_bloodmyst_isle.cpp

@@ -330,8 +330,11 @@ public:
                     std::list<Creature*> creatureList;
                     GetCreatureListWithEntryInGrid(creatureList, me, NPC_BLOODMYST_TESLA_COIL, 500.0f);
                     if (!creatureList.empty())
+                    {
                         for (std::list<Creature*>::iterator itr = creatureList.begin(); itr != creatureList.end(); ++itr)
                             (*itr)->InterruptNonMeleeSpells(true, SPELL_BLOODMYST_TESLA);
+                    }
+                    break;
                 }
                 default:
                     break;

src/server/scripts/Northrend/IcecrownCitadel/boss_professor_putricide.cpp

@@ -691,6 +691,7 @@ class boss_professor_putricide : public CreatureScript
                                 default:
                                     break;
                             }
+                            break;
                         }
                         default:
                             break;

src/server/scripts/Northrend/IcecrownCitadel/boss_rotface.cpp

@@ -352,6 +352,7 @@ class npc_big_ooze : public CreatureScript
                         case EVENT_STICKY_OOZE:
                             DoCastVictim(SPELL_STICKY_OOZE);
                             events.ScheduleEvent(EVENT_STICKY_OOZE, 15s);
+                            break;
                         default:
                             break;
                     }

src/server/scripts/Northrend/Naxxramas/boss_kelthuzad.cpp

@@ -815,6 +815,7 @@ public:
                         me->SetImmuneToPC(true);
                         me->DespawnOrUnsummon(30 * IN_MILLISECONDS); // just in case anything interrupts the movement
                         me->GetMotionMaster()->MoveTargetedHome();
+                        break;
                     default:
                         break;
                 }

src/server/scripts/Northrend/Naxxramas/boss_thaddius.cpp

@@ -796,6 +796,7 @@ public:
                         if (GameObject* coil = myCoilGO())
                             coil->SetGoState(GO_STATE_READY);
                         me->DespawnOrUnsummon(0, Hours(24 * 7));
+                        break;
                     default:
                         break;
                 }

src/server/scripts/Northrend/Ulduar/Ulduar/boss_flame_leviathan.cpp

@@ -357,6 +357,7 @@ class boss_flame_leviathan : public CreatureScript
                     case DATA_ORBIT_ACHIEVEMENTS:
                         if (ActiveTowers) // Only on HardMode
                             return ActiveTowersCount;
+                        break;
                     default:
                         break;
                 }

src/server/scripts/Outland/BlackTemple/instance_black_temple.cpp

@@ -169,6 +169,7 @@ class instance_black_temple : public InstanceMapScript
                         break;
                     case DATA_AKAMA_ILLIDAN_INTRO:
                         AkamaIllidanIntro = data;
+                        break;
                     default:
                         break;
                 }