diff --git a/apps/openmw/mwgui/charactercreation.cpp b/apps/openmw/mwgui/charactercreation.cpp
index b2c9f1038..2deb62215 100644
--- a/apps/openmw/mwgui/charactercreation.cpp
+++ b/apps/openmw/mwgui/charactercreation.cpp
@@ -246,8 +246,8 @@ namespace MWGui
                     mReviewDialog->setBirthSign(player.getBirthSign());
 
                     {
-                        MWWorld::Ptr player = MWMechanics::getPlayer();
-                        const MWMechanics::CreatureStats& stats = player.getClass().getCreatureStats(player);
+                        MWWorld::Ptr playerPtr = MWMechanics::getPlayer();
+                        const MWMechanics::CreatureStats& stats = playerPtr.getClass().getCreatureStats(playerPtr);
 
                         mReviewDialog->setHealth ( stats.getHealth()  );
                         mReviewDialog->setMagicka( stats.getMagicka() );
diff --git a/apps/openmw/mwmechanics/actors.cpp b/apps/openmw/mwmechanics/actors.cpp
index 2b475e475..431ad09b3 100644
--- a/apps/openmw/mwmechanics/actors.cpp
+++ b/apps/openmw/mwmechanics/actors.cpp
@@ -78,7 +78,7 @@ class CheckActorCommanded : public MWMechanics::EffectSourceVisitor
     MWWorld::Ptr mActor;
 public:
     bool mCommanded;
-    CheckActorCommanded(MWWorld::Ptr actor)
+    CheckActorCommanded(const MWWorld::Ptr& actor)
         : mActor(actor)
     , mCommanded(false){}
 
@@ -114,9 +114,7 @@ void adjustCommandedActor (const MWWorld::Ptr& actor)
     }
 
     if (!check.mCommanded && hasCommandPackage)
-    {
         stats.getAiSequence().erase(it);
-    }
 }
 
 void getRestorationPerHourOfSleep (const MWWorld::Ptr& ptr, float& health, float& magicka)
@@ -151,7 +149,7 @@ namespace MWMechanics
         MWWorld::Ptr mActor;
         bool mTrapped;
     public:
-        SoulTrap(MWWorld::Ptr trappedCreature)
+        SoulTrap(const MWWorld::Ptr& trappedCreature)
             : mCreature(trappedCreature)
             , mTrapped(false)
         {
@@ -722,16 +720,8 @@ namespace MWMechanics
 
         // any value of calm > 0 will stop the actor from fighting
         if ((effects.get(ESM::MagicEffect::CalmHumanoid).getMagnitude() > 0 && ptr.getClass().isNpc())
-                || (effects.get(ESM::MagicEffect::CalmCreature).getMagnitude() > 0 && !ptr.getClass().isNpc()))
-        {
-            for (std::list<AiPackage*>::const_iterator it = creatureStats.getAiSequence().begin(); it != creatureStats.getAiSequence().end(); )
-            {
-                if ((*it)->getTypeId() == AiPackage::TypeIdCombat)
-                    it = creatureStats.getAiSequence().erase(it);
-                else
-                    ++it;
-            }
-        }
+            || (effects.get(ESM::MagicEffect::CalmCreature).getMagnitude() > 0 && !ptr.getClass().isNpc()))
+            creatureStats.getAiSequence().stopCombat();
 
         // Update bound effects
         // Note: in vanilla MW multiple bound items of the same type can be created by different spells.
@@ -820,7 +810,7 @@ namespace MWMechanics
         NpcStats &stats = ptr.getClass().getNpcStats(ptr);
 
         // When npc stats are just initialized, mTimeToStartDrowning == -1 and we should get value from GMST
-        static const int fHoldBreathTime = MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fHoldBreathTime")->getFloat();
+        static const float fHoldBreathTime = MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fHoldBreathTime")->getFloat();
         if (stats.getTimeToStartDrowning() == -1.f)
             stats.setTimeToStartDrowning(fHoldBreathTime);
 
@@ -860,10 +850,7 @@ namespace MWMechanics
             }
         }
         else
-        {
-            static const float fHoldBreathTime = world->getStore().get<ESM::GameSetting>().find("fHoldBreathTime")->getFloat();
             stats.setTimeToStartDrowning(fHoldBreathTime);
-        }
     }
 
     void Actors::updateEquippedLight (const MWWorld::Ptr& ptr, float duration)
diff --git a/apps/openmw/mwmechanics/aisequence.cpp b/apps/openmw/mwmechanics/aisequence.cpp
index 84c8eca49..125805507 100644
--- a/apps/openmw/mwmechanics/aisequence.cpp
+++ b/apps/openmw/mwmechanics/aisequence.cpp
@@ -96,16 +96,16 @@ std::list<AiPackage*>::const_iterator AiSequence::end() const
     return mPackages.end();
 }
 
-std::list<AiPackage*>::const_iterator AiSequence::erase(std::list<AiPackage*>::const_iterator package)
+void AiSequence::erase(std::list<AiPackage*>::const_iterator package)
 {
     // Not sure if manually terminated packages should trigger mDone, probably not?
     for(std::list<AiPackage*>::iterator it = mPackages.begin(); it != mPackages.end(); ++it)
     {
         if (package == it)
         {
-            AiPackage* packagePtr = *it;
-            delete packagePtr;
-            return mPackages.erase(it);
+            delete *it;
+            mPackages.erase(it);
+            return;
         }
     }
     throw std::runtime_error("can't find package to erase");
diff --git a/apps/openmw/mwmechanics/aisequence.hpp b/apps/openmw/mwmechanics/aisequence.hpp
index 4f8b542a4..4b6ec156a 100644
--- a/apps/openmw/mwmechanics/aisequence.hpp
+++ b/apps/openmw/mwmechanics/aisequence.hpp
@@ -64,7 +64,7 @@ namespace MWMechanics
             std::list<AiPackage*>::const_iterator begin() const;
             std::list<AiPackage*>::const_iterator end() const;
 
-            std::list<AiPackage*>::const_iterator erase (std::list<AiPackage*>::const_iterator package);
+            void erase (std::list<AiPackage*>::const_iterator package);
 
             /// Returns currently executing AiPackage type
             /** \see enum AiPackage::TypeId **/
diff --git a/apps/openmw/mwmechanics/aiwander.cpp b/apps/openmw/mwmechanics/aiwander.cpp
index 5396b5b39..eba37d7a7 100644
--- a/apps/openmw/mwmechanics/aiwander.cpp
+++ b/apps/openmw/mwmechanics/aiwander.cpp
@@ -893,7 +893,7 @@ namespace MWMechanics
         storage.mAllowedNodes.push_back(PathFinder::MakePathgridPoint(vectorStart + delta));
     }
 
-    void AiWander::SetCurrentNodeToClosestAllowedNode(osg::Vec3f npcPos, AiWanderStorage& storage)
+    void AiWander::SetCurrentNodeToClosestAllowedNode(const osg::Vec3f& npcPos, AiWanderStorage& storage)
     {
         float distanceToClosestNode = std::numeric_limits<float>::max();
         unsigned int index = 0;
diff --git a/apps/openmw/mwmechanics/aiwander.hpp b/apps/openmw/mwmechanics/aiwander.hpp
index f9b03ca5e..13a4a1b4a 100644
--- a/apps/openmw/mwmechanics/aiwander.hpp
+++ b/apps/openmw/mwmechanics/aiwander.hpp
@@ -122,7 +122,7 @@ namespace MWMechanics
             /// convert point from local (i.e. cell) to world coordinates
             void ToWorldCoordinates(ESM::Pathgrid::Point& point, const ESM::Cell * cell);
 
-            void SetCurrentNodeToClosestAllowedNode(osg::Vec3f npcPos, AiWanderStorage& storage);
+            void SetCurrentNodeToClosestAllowedNode(const osg::Vec3f& npcPos, AiWanderStorage& storage);
 
             void AddNonPathGridAllowedPoints(osg::Vec3f npcPos, const ESM::Pathgrid * pathGrid, int pointIndex, AiWanderStorage& storage);
 
diff --git a/apps/openmw/mwmechanics/character.cpp b/apps/openmw/mwmechanics/character.cpp
index 85749d947..b71f31550 100644
--- a/apps/openmw/mwmechanics/character.cpp
+++ b/apps/openmw/mwmechanics/character.cpp
@@ -2242,7 +2242,7 @@ void CharacterController::setAttackingOrSpell(bool attackingOrSpell)
     mAttackingOrSpell = attackingOrSpell;
 }
 
-void CharacterController::setAIAttackType(std::string attackType)
+void CharacterController::setAIAttackType(const std::string& attackType)
 {
     mAttackType = attackType;
 }
diff --git a/apps/openmw/mwmechanics/character.hpp b/apps/openmw/mwmechanics/character.hpp
index 9db127084..a3cdf097d 100644
--- a/apps/openmw/mwmechanics/character.hpp
+++ b/apps/openmw/mwmechanics/character.hpp
@@ -268,7 +268,7 @@ public:
     bool isSneaking() const;
 
     void setAttackingOrSpell(bool attackingOrSpell);
-    void setAIAttackType(std::string attackType); // set and used by AiCombat
+    void setAIAttackType(const std::string& attackType);
     static void setAttackTypeRandomly(std::string& attackType);
 
     bool readyToPrepareAttack() const;
diff --git a/apps/openmw/mwmechanics/enchanting.cpp b/apps/openmw/mwmechanics/enchanting.cpp
index 57ece6a79..714b5a09c 100644
--- a/apps/openmw/mwmechanics/enchanting.cpp
+++ b/apps/openmw/mwmechanics/enchanting.cpp
@@ -21,7 +21,7 @@ namespace MWMechanics
         , mSelfEnchanting(false)
     {}
 
-    void Enchanting::setOldItem(MWWorld::Ptr oldItem)
+    void Enchanting::setOldItem(const MWWorld::Ptr& oldItem)
     {
         mOldItemPtr=oldItem;
         if(!itemEmpty())
@@ -39,7 +39,7 @@ namespace MWMechanics
         mNewItemName=s;
     }
 
-    void Enchanting::setEffect(ESM::EffectList effectList)
+    void Enchanting::setEffect(const ESM::EffectList& effectList)
     {
         mEffectList=effectList;
     }
@@ -49,7 +49,7 @@ namespace MWMechanics
         return mCastStyle;
     }
 
-    void Enchanting::setSoulGem(MWWorld::Ptr soulGem)
+    void Enchanting::setSoulGem(const MWWorld::Ptr& soulGem)
     {
         mSoulGemPtr=soulGem;
     }
@@ -269,7 +269,7 @@ namespace MWMechanics
         mSelfEnchanting = selfEnchanting;
     }
 
-    void Enchanting::setEnchanter(MWWorld::Ptr enchanter)
+    void Enchanting::setEnchanter(const MWWorld::Ptr& enchanter)
     {
         mEnchanter = enchanter;
     }
diff --git a/apps/openmw/mwmechanics/enchanting.hpp b/apps/openmw/mwmechanics/enchanting.hpp
index a53027bb9..8e3b00e5a 100644
--- a/apps/openmw/mwmechanics/enchanting.hpp
+++ b/apps/openmw/mwmechanics/enchanting.hpp
@@ -29,14 +29,14 @@ namespace MWMechanics
 
         public:
             Enchanting();
-            void setEnchanter(MWWorld::Ptr enchanter);
+            void setEnchanter(const MWWorld::Ptr& enchanter);
             void setSelfEnchanting(bool selfEnchanting);
-            void setOldItem(MWWorld::Ptr oldItem);
+            void setOldItem(const MWWorld::Ptr& oldItem);
             MWWorld::Ptr getOldItem() { return mOldItemPtr; }
             MWWorld::Ptr getGem() { return mSoulGemPtr; }
             void setNewItemName(const std::string& s);
-            void setEffect(ESM::EffectList effectList);
-            void setSoulGem(MWWorld::Ptr soulGem);
+            void setEffect(const ESM::EffectList& effectList);
+            void setSoulGem(const MWWorld::Ptr& soulGem);
             bool create(); //Return true if created, false if failed.
             void nextCastStyle(); //Set enchant type to next possible type (for mOldItemPtr object)
             int getCastStyle() const;
diff --git a/apps/openmw/mwmechanics/pathfinding.cpp b/apps/openmw/mwmechanics/pathfinding.cpp
index b0bdce8f1..5c0456096 100644
--- a/apps/openmw/mwmechanics/pathfinding.cpp
+++ b/apps/openmw/mwmechanics/pathfinding.cpp
@@ -15,7 +15,7 @@ namespace
     // Chooses a reachable end pathgrid point.  start is assumed reachable.
     std::pair<int, bool> getClosestReachablePoint(const ESM::Pathgrid* grid,
                                                   const MWWorld::CellStore *cell,
-                                                  const osg::Vec3f pos, int start)
+                                                  const osg::Vec3f& pos, int start)
     {
         assert(grid && !grid->mPoints.empty());
 
diff --git a/apps/openmw/mwphysics/physicssystem.cpp b/apps/openmw/mwphysics/physicssystem.cpp
index 40805a4b1..d209d0d95 100644
--- a/apps/openmw/mwphysics/physicssystem.cpp
+++ b/apps/openmw/mwphysics/physicssystem.cpp
@@ -794,7 +794,7 @@ namespace MWPhysics
         btVector3 mContactPoint;
         btScalar mLeastDistSqr;
 
-        DeepestNotMeContactTestResultCallback(const btCollisionObject* me, const std::vector<const btCollisionObject*> targets, const btVector3 &origin)
+        DeepestNotMeContactTestResultCallback(const btCollisionObject* me, const std::vector<const btCollisionObject*>& targets, const btVector3 &origin)
           : mMe(me), mTargets(targets), mOrigin(origin), mObject(NULL), mContactPoint(0,0,0),
             mLeastDistSqr(std::numeric_limits<float>::max())
         { }
@@ -912,7 +912,7 @@ namespace MWPhysics
     class ClosestNotMeRayResultCallback : public btCollisionWorld::ClosestRayResultCallback
     {
     public:
-        ClosestNotMeRayResultCallback(const btCollisionObject* me, const std::vector<const btCollisionObject*> targets, const btVector3& from, const btVector3& to)
+        ClosestNotMeRayResultCallback(const btCollisionObject* me, const std::vector<const btCollisionObject*>& targets, const btVector3& from, const btVector3& to)
             : btCollisionWorld::ClosestRayResultCallback(from, to)
             , mMe(me), mTargets(targets)
         {
@@ -938,7 +938,7 @@ namespace MWPhysics
         const std::vector<const btCollisionObject*> mTargets;
     };
 
-    PhysicsSystem::RayResult PhysicsSystem::castRay(const osg::Vec3f &from, const osg::Vec3f &to, MWWorld::ConstPtr ignore, std::vector<MWWorld::Ptr> targets, int mask, int group) const
+    PhysicsSystem::RayResult PhysicsSystem::castRay(const osg::Vec3f &from, const osg::Vec3f &to, const MWWorld::ConstPtr& ignore, std::vector<MWWorld::Ptr> targets, int mask, int group) const
     {
         btVector3 btFrom = toBullet(from);
         btVector3 btTo = toBullet(to);
diff --git a/apps/openmw/mwphysics/physicssystem.hpp b/apps/openmw/mwphysics/physicssystem.hpp
index 81385d675..5351d99dd 100644
--- a/apps/openmw/mwphysics/physicssystem.hpp
+++ b/apps/openmw/mwphysics/physicssystem.hpp
@@ -114,7 +114,7 @@ namespace MWPhysics
             };
 
             /// @param me Optional, a Ptr to ignore in the list of results. targets are actors to filter for, ignoring all other actors.
-            RayResult castRay(const osg::Vec3f &from, const osg::Vec3f &to, MWWorld::ConstPtr ignore = MWWorld::ConstPtr(),
+            RayResult castRay(const osg::Vec3f &from, const osg::Vec3f &to, const MWWorld::ConstPtr& ignore = MWWorld::ConstPtr(),
                     std::vector<MWWorld::Ptr> targets = std::vector<MWWorld::Ptr>(),
                     int mask = CollisionType_World|CollisionType_HeightMap|CollisionType_Actor|CollisionType_Door, int group=0xff) const;
 
diff --git a/apps/openmw/mwrender/animation.cpp b/apps/openmw/mwrender/animation.cpp
index fe20ac437..c825e74f2 100644
--- a/apps/openmw/mwrender/animation.cpp
+++ b/apps/openmw/mwrender/animation.cpp
@@ -282,7 +282,7 @@ namespace MWRender
     class GlowUpdater : public SceneUtil::StateSetUpdater
     {
     public:
-        GlowUpdater(int texUnit, osg::Vec4f color, const std::vector<osg::ref_ptr<osg::Texture2D> >& textures,
+        GlowUpdater(int texUnit, const osg::Vec4f& color, const std::vector<osg::ref_ptr<osg::Texture2D> >& textures,
             osg::Node* node, float duration, Resource::ResourceSystem* resourcesystem)
             : mTexUnit(texUnit)
             , mColor(color)
@@ -383,7 +383,7 @@ namespace MWRender
             return mDone;
         }
 
-        void setColor(osg::Vec4f color)
+        void setColor(const osg::Vec4f& color)
         {
             mColor = color;
             mColorChanged = true;
@@ -1362,7 +1362,7 @@ namespace MWRender
                             useQuadratic, quadraticValue, quadraticRadiusMult, useLinear, linearRadiusMult, linearValue);
     }
 
-    void Animation::addEffect (const std::string& model, int effectId, bool loop, const std::string& bonename, std::string texture)
+    void Animation::addEffect (const std::string& model, int effectId, bool loop, const std::string& bonename, const std::string& texture)
     {
         if (!mObjectRoot.get())
             return;
diff --git a/apps/openmw/mwrender/animation.hpp b/apps/openmw/mwrender/animation.hpp
index 27572544f..202595182 100644
--- a/apps/openmw/mwrender/animation.hpp
+++ b/apps/openmw/mwrender/animation.hpp
@@ -362,7 +362,7 @@ public:
      * @param texture override the texture specified in the model's materials - if empty, do not override
      * @note Will not add an effect twice.
      */
-    void addEffect (const std::string& model, int effectId, bool loop = false, const std::string& bonename = "", std::string texture = "");
+    void addEffect (const std::string& model, int effectId, bool loop = false, const std::string& bonename = "", const std::string& texture = "");
     void removeEffect (int effectId);
     void getLoopingEffects (std::vector<int>& out) const;
 
diff --git a/apps/openmw/mwrender/characterpreview.cpp b/apps/openmw/mwrender/characterpreview.cpp
index dfb737d5e..db778e88d 100644
--- a/apps/openmw/mwrender/characterpreview.cpp
+++ b/apps/openmw/mwrender/characterpreview.cpp
@@ -105,7 +105,7 @@ namespace MWRender
     };
 
     CharacterPreview::CharacterPreview(osg::Group* parent, Resource::ResourceSystem* resourceSystem,
-                                       MWWorld::Ptr character, int sizeX, int sizeY, const osg::Vec3f& position, const osg::Vec3f& lookAt)
+                                       const MWWorld::Ptr& character, int sizeX, int sizeY, const osg::Vec3f& position, const osg::Vec3f& lookAt)
         : mParent(parent)
         , mResourceSystem(resourceSystem)
         , mPosition(position)
@@ -244,7 +244,7 @@ namespace MWRender
     // --------------------------------------------------------------------------------------------------
 
 
-    InventoryPreview::InventoryPreview(osg::Group* parent, Resource::ResourceSystem* resourceSystem, MWWorld::Ptr character)
+    InventoryPreview::InventoryPreview(osg::Group* parent, Resource::ResourceSystem* resourceSystem, const MWWorld::Ptr& character)
         : CharacterPreview(parent, resourceSystem, character, 512, 1024, osg::Vec3f(0, 700, 71), osg::Vec3f(0,0,71))
     {
     }
diff --git a/apps/openmw/mwrender/characterpreview.hpp b/apps/openmw/mwrender/characterpreview.hpp
index 273bacedb..f0d5ad0c9 100644
--- a/apps/openmw/mwrender/characterpreview.hpp
+++ b/apps/openmw/mwrender/characterpreview.hpp
@@ -28,7 +28,7 @@ namespace MWRender
     class CharacterPreview
     {
     public:
-        CharacterPreview(osg::Group* parent, Resource::ResourceSystem* resourceSystem, MWWorld::Ptr character, int sizeX, int sizeY,
+        CharacterPreview(osg::Group* parent, Resource::ResourceSystem* resourceSystem, const MWWorld::Ptr& character, int sizeX, int sizeY,
                          const osg::Vec3f& position, const osg::Vec3f& lookAt);
         virtual ~CharacterPreview();
 
@@ -73,7 +73,7 @@ namespace MWRender
     {
     public:
 
-        InventoryPreview(osg::Group* parent, Resource::ResourceSystem* resourceSystem, MWWorld::Ptr character);
+        InventoryPreview(osg::Group* parent, Resource::ResourceSystem* resourceSystem, const MWWorld::Ptr& character);
 
         void updatePtr(const MWWorld::Ptr& ptr);
 
diff --git a/apps/openmw/mwrender/npcanimation.cpp b/apps/openmw/mwrender/npcanimation.cpp
index 87b6ae2bc..6e95ce481 100644
--- a/apps/openmw/mwrender/npcanimation.cpp
+++ b/apps/openmw/mwrender/npcanimation.cpp
@@ -99,7 +99,7 @@ private:
 private:
     void resetBlinkTimer();
 public:
-    HeadAnimationTime(MWWorld::Ptr reference);
+    HeadAnimationTime(const MWWorld::Ptr& reference);
 
     void updatePtr(const MWWorld::Ptr& updated);
 
@@ -128,7 +128,7 @@ public:
     {
     }
 
-    void setOffset(osg::Vec3f offset)
+    void setOffset(const osg::Vec3f& offset)
     {
         mOffset = offset;
     }
@@ -155,7 +155,7 @@ private:
 
 // --------------------------------------------------------------------------------------------------------------
 
-HeadAnimationTime::HeadAnimationTime(MWWorld::Ptr reference)
+HeadAnimationTime::HeadAnimationTime(const MWWorld::Ptr& reference)
     : mReference(reference), mTalkStart(0), mTalkStop(0), mBlinkStart(0), mBlinkStop(0), mEnabled(true), mValue(0)
 {
     resetBlinkTimer();
diff --git a/apps/openmw/mwrender/objects.hpp b/apps/openmw/mwrender/objects.hpp
index 8864e4483..659853763 100644
--- a/apps/openmw/mwrender/objects.hpp
+++ b/apps/openmw/mwrender/objects.hpp
@@ -37,7 +37,7 @@ class Animation;
 class PtrHolder : public osg::Object
 {
 public:
-    PtrHolder(MWWorld::Ptr ptr)
+    PtrHolder(const MWWorld::Ptr& ptr)
         : mPtr(ptr)
     {
     }
diff --git a/apps/openmw/mwrender/util.cpp b/apps/openmw/mwrender/util.cpp
index 74047b58b..ed10d86ac 100644
--- a/apps/openmw/mwrender/util.cpp
+++ b/apps/openmw/mwrender/util.cpp
@@ -14,7 +14,7 @@ namespace MWRender
 class TextureOverrideVisitor : public osg::NodeVisitor
     {
     public:
-        TextureOverrideVisitor(std::string texture, Resource::ResourceSystem* resourcesystem)
+        TextureOverrideVisitor(const std::string& texture, Resource::ResourceSystem* resourcesystem)
             : osg::NodeVisitor(TRAVERSE_ALL_CHILDREN)
             , mTexture(texture)
             , mResourcesystem(resourcesystem)
diff --git a/apps/openmw/mwscript/interpretercontext.cpp b/apps/openmw/mwscript/interpretercontext.cpp
index 0c70b6996..2462d72ae 100644
--- a/apps/openmw/mwscript/interpretercontext.cpp
+++ b/apps/openmw/mwscript/interpretercontext.cpp
@@ -137,7 +137,7 @@ namespace MWScript
 
 
     InterpreterContext::InterpreterContext (
-        MWScript::Locals *locals, MWWorld::Ptr reference, const std::string& targetId)
+        MWScript::Locals *locals, const MWWorld::Ptr& reference, const std::string& targetId)
     : mLocals (locals), mReference (reference), mTargetId (targetId)
     {
         // If we run on a reference (local script, dialogue script or console with object
diff --git a/apps/openmw/mwscript/interpretercontext.hpp b/apps/openmw/mwscript/interpretercontext.hpp
index fdd5aa55f..80861d1a7 100644
--- a/apps/openmw/mwscript/interpretercontext.hpp
+++ b/apps/openmw/mwscript/interpretercontext.hpp
@@ -51,7 +51,7 @@ namespace MWScript
 
         public:
 
-            InterpreterContext (MWScript::Locals *locals, MWWorld::Ptr reference,
+            InterpreterContext (MWScript::Locals *locals, const MWWorld::Ptr& reference,
                 const std::string& targetId = "");
             ///< The ownership of \a locals is not transferred. 0-pointer allowed.
 
diff --git a/apps/openmw/mwworld/player.cpp b/apps/openmw/mwworld/player.cpp
index fe13a4d60..d233fba6f 100644
--- a/apps/openmw/mwworld/player.cpp
+++ b/apps/openmw/mwworld/player.cpp
@@ -255,7 +255,7 @@ namespace MWWorld
         return MWBase::Environment::get().getMechanicsManager()->getEnemiesNearby(getPlayer()).size() != 0;
     }
 
-    void Player::markPosition(CellStore *markedCell, ESM::Position markedPosition)
+    void Player::markPosition(CellStore *markedCell, const ESM::Position& markedPosition)
     {
         mMarkedCell = markedCell;
         mMarkedPosition = markedPosition;
diff --git a/apps/openmw/mwworld/player.hpp b/apps/openmw/mwworld/player.hpp
index 157501803..4ba66e37e 100644
--- a/apps/openmw/mwworld/player.hpp
+++ b/apps/openmw/mwworld/player.hpp
@@ -61,7 +61,7 @@ namespace MWWorld
         void setWerewolfSkillsAttributes();
 
         // For mark/recall magic effects
-        void markPosition (CellStore* markedCell, ESM::Position markedPosition);
+        void markPosition (CellStore* markedCell, const ESM::Position& markedPosition);
         void getMarkedPosition (CellStore*& markedCell, ESM::Position& markedPosition) const;
 
         /// Interiors can not always be mapped to a world position. However
diff --git a/apps/openmw/mwworld/worldimp.cpp b/apps/openmw/mwworld/worldimp.cpp
index 536f5ac76..217a06ee1 100644
--- a/apps/openmw/mwworld/worldimp.cpp
+++ b/apps/openmw/mwworld/worldimp.cpp
@@ -2989,7 +2989,7 @@ namespace MWWorld
 
     struct AddDetectedReferenceVisitor
     {
-        AddDetectedReferenceVisitor(std::vector<Ptr>& out, Ptr detector, World::DetectionType type, float squaredDist)
+        AddDetectedReferenceVisitor(std::vector<Ptr>& out, const Ptr& detector, World::DetectionType type, float squaredDist)
             : mOut(out), mDetector(detector), mSquaredDist(squaredDist), mType(type)
         {
         }
diff --git a/components/esm/esmwriter.hpp b/components/esm/esmwriter.hpp
index d11b3c940..5d7aebaf9 100644
--- a/components/esm/esmwriter.hpp
+++ b/components/esm/esmwriter.hpp
@@ -86,7 +86,7 @@ private:
         // Prevent using writeHNT with strings. This already happened by accident and results in
         // state being discarded without any error on writing or reading it. :(
         // writeHNString and friends must be used instead.
-        void writeHNT(const std::string &name, std::string data)
+        void writeHNT(const std::string& name, const std::string& data)
         {
         }
         void writeT(const std::string& data)
diff --git a/components/nifosg/controller.cpp b/components/nifosg/controller.cpp
index 8d0c73bff..87a0b830e 100644
--- a/components/nifosg/controller.cpp
+++ b/components/nifosg/controller.cpp
@@ -218,7 +218,7 @@ UVController::UVController()
 {
 }
 
-UVController::UVController(const Nif::NiUVData *data, std::set<int> textureUnits)
+UVController::UVController(const Nif::NiUVData *data, const std::set<int>& textureUnits)
     : mUTrans(data->mKeyList[0], 0.f)
     , mVTrans(data->mKeyList[1], 0.f)
     , mUScale(data->mKeyList[2], 1.f)
@@ -381,14 +381,14 @@ void MaterialColorController::apply(osg::StateSet *stateset, osg::NodeVisitor *n
     }
 }
 
-FlipController::FlipController(const Nif::NiFlipController *ctrl, std::vector<osg::ref_ptr<osg::Texture2D> > textures)
+FlipController::FlipController(const Nif::NiFlipController *ctrl, const std::vector<osg::ref_ptr<osg::Texture2D> >& textures)
     : mTexSlot(ctrl->mTexSlot)
     , mDelta(ctrl->mDelta)
     , mTextures(textures)
 {
 }
 
-FlipController::FlipController(int texSlot, float delta, std::vector<osg::ref_ptr<osg::Texture2D> > textures)
+FlipController::FlipController(int texSlot, float delta, const std::vector<osg::ref_ptr<osg::Texture2D> >& textures)
     : mTexSlot(texSlot)
     , mDelta(delta)
     , mTextures(textures)
diff --git a/components/nifosg/controller.hpp b/components/nifosg/controller.hpp
index ce268f587..e517f9189 100644
--- a/components/nifosg/controller.hpp
+++ b/components/nifosg/controller.hpp
@@ -223,7 +223,7 @@ namespace NifOsg
     public:
         UVController();
         UVController(const UVController&,const osg::CopyOp&);
-        UVController(const Nif::NiUVData *data, std::set<int> textureUnits);
+        UVController(const Nif::NiUVData *data, const std::set<int>& textureUnits);
 
         META_Object(NifOsg,UVController)
 
@@ -297,8 +297,8 @@ namespace NifOsg
         std::vector<osg::ref_ptr<osg::Texture2D> > mTextures;
 
     public:
-        FlipController(const Nif::NiFlipController* ctrl, std::vector<osg::ref_ptr<osg::Texture2D> > textures);
-        FlipController(int texSlot, float delta, std::vector<osg::ref_ptr<osg::Texture2D> > textures);
+        FlipController(const Nif::NiFlipController* ctrl, const std::vector<osg::ref_ptr<osg::Texture2D> >& textures);
+        FlipController(int texSlot, float delta, const std::vector<osg::ref_ptr<osg::Texture2D> >& textures);
         FlipController();
         FlipController(const FlipController& copy, const osg::CopyOp& copyop);