diff --git a/src/d_player.h b/src/d_player.h
index 168327f8a..60acb25d2 100644
--- a/src/d_player.h
+++ b/src/d_player.h
@@ -73,13 +73,14 @@ class PClassPlayerPawn : public PClassActor
 {
 	DECLARE_CLASS(PClassPlayerPawn, PClassActor);
 protected:
-	virtual void Derive(PClass *newclass);
 public:
 	PClassPlayerPawn();
+	virtual void DeriveData(PClass *newclass);
 	void EnumColorSets(TArray<int> *out);
 	FPlayerColorSet *GetColorSet(int setnum) { return ColorSets.CheckKey(setnum); }
 	void SetPainFlash(FName type, PalEntry color);
 	bool GetPainFlash(FName type, PalEntry *color) const;
+	virtual void ReplaceClassRef(PClass *oldclass, PClass *newclass);
 
 	FString DisplayName;	// Display name (used in menus, etc.)
 	FString SoundClass;		// Sound class
diff --git a/src/dobject.h b/src/dobject.h
index 4b6f1ec49..f478cfc08 100644
--- a/src/dobject.h
+++ b/src/dobject.h
@@ -98,6 +98,7 @@ enum
 	CLASSREG_PClassPlayerPawn,
 	CLASSREG_PClassType,
 	CLASSREG_PClassClass,
+	CLASSREG_PClassWeaponPiece
 };
 
 struct ClassReg
diff --git a/src/dobjtype.cpp b/src/dobjtype.cpp
index 7e80eca0c..1762079fb 100644
--- a/src/dobjtype.cpp
+++ b/src/dobjtype.cpp
@@ -44,6 +44,7 @@
 #include "autosegs.h"
 #include "v_text.h"
 #include "a_pickups.h"
+#include "a_weaponpiece.h"
 #include "d_player.h"
 #include "fragglescript/t_fs.h"
 
@@ -2163,6 +2164,7 @@ PClass *ClassReg::RegisterClass()
 		&PClassPlayerPawn::RegistrationInfo,
 		&PClassType::RegistrationInfo,
 		&PClassClass::RegistrationInfo,
+		&PClassWeaponPiece::RegistrationInfo,
 	};
 
 	// Skip classes that have already been registered
@@ -2318,42 +2320,50 @@ PClass *PClass::CreateDerivedClass(FName name, unsigned int size)
 	assert (size >= Size);
 	PClass *type;
 	bool notnew;
+	size_t bucket;
 
-	const PClass *existclass = FindClass(name);
+	PClass *existclass = static_cast<PClass *>(TypeTable.FindType(RUNTIME_CLASS(PClass), /*FIXME:Outer*/0, name, &bucket));
 
 	// This is a placeholder so fill it in
-	if (existclass != NULL && (existclass->Size == TClass_Fatal || existclass->Size == TClass_Nonfatal))
+	if (existclass != NULL && (existclass->Size == TentativeClass))
 	{
 		type = const_cast<PClass*>(existclass);
 		if (!IsDescendantOf(type->ParentClass))
 		{
-			if (existclass->Size == TClass_Fatal)
-			{
-				I_Error("%s must inherit from %s but doesn't.", name.GetChars(), type->ParentClass->TypeName.GetChars());
-			}
-			else
-			{
-				Printf(TEXTCOLOR_RED "%s must inherit from %s but doesn't.", name.GetChars(), type->ParentClass->TypeName.GetChars());
-			}
+			I_Error("%s must inherit from %s but doesn't.", name.GetChars(), type->ParentClass->TypeName.GetChars());
 		}
 		DPrintf("Defining placeholder class %s\n", name.GetChars());
 		notnew = true;
 	}
 	else
 	{
-		// Create a new type object of the same type as us. (We may be a derived class of PClass.)
-		type = static_cast<PClass *>(GetClass()->CreateNew());
 		notnew = false;
 	}
 
+	// Create a new type object of the same type as us. (We may be a derived class of PClass.)
+	type = static_cast<PClass *>(GetClass()->CreateNew());
+
 	type->TypeName = name;
 	type->Size = size;
 	type->bRuntimeClass = true;
 	Derive(type);
+	DeriveData(type);
 	if (!notnew)
 	{
 		type->InsertIntoHash();
 	}
+	else
+	{
+		PClassActor::AllActorClasses.Pop();	// remove the newly added class from the list
+		// todo: replace all affected fields
+		for (unsigned i = 0; i < PClassActor::AllActorClasses.Size(); i++)
+		{
+			PClassActor::AllActorClasses[i]->ReplaceClassRef(existclass, type);
+			if (PClassActor::AllActorClasses[i] == existclass)
+				PClassActor::AllActorClasses[i] = static_cast<PClassActor*>(type);
+		}
+		TypeTable.ReplaceType(type, existclass, bucket);
+	}
 	return type;
 }
 
@@ -2403,11 +2413,11 @@ PClass *PClass::FindClassTentative(FName name, bool fatal)
 		return static_cast<PClass *>(found);
 	}
 	PClass *type = static_cast<PClass *>(GetClass()->CreateNew());
-	DPrintf("Creating placeholder class %s : %s\n", name.GetChars(), TypeName.GetChars());
+	Printf("Creating placeholder class %s : %s\n", name.GetChars(), TypeName.GetChars());
 
 	type->TypeName = name;
 	type->ParentClass = this;
-	type->Size = fatal? TClass_Fatal : TClass_Nonfatal;
+	type->Size = TentativeClass;
 	type->bRuntimeClass = true;
 	TypeTable.AddType(type, RUNTIME_CLASS(PClass), (intptr_t)type->Outer, name, bucket);
 	return type;
diff --git a/src/dobjtype.h b/src/dobjtype.h
index 900059cab..9ba327658 100644
--- a/src/dobjtype.h
+++ b/src/dobjtype.h
@@ -601,8 +601,7 @@ public:
 
 enum
 {
-	TClass_Fatal = UINT_MAX,
-	TClass_Nonfatal = UINT_MAX - 1
+	TentativeClass = UINT_MAX,
 };
 
 class PClassClass;
@@ -611,13 +610,14 @@ class PClass : public PStruct
 	DECLARE_CLASS(PClass, PStruct);
 	HAS_OBJECT_POINTERS;
 protected:
-	virtual void Derive(PClass *newclass);
 	// We unravel _WITH_META here just as we did for PType.
 	enum { MetaClassNum = CLASSREG_PClassClass };
+	virtual void Derive(PClass *newclass);
 public:
 	typedef PClassClass MetaClass;
 	MetaClass *GetClass() const;
 
+	virtual void DeriveData(PClass *newclass) {}
 	static void StaticInit();
 	static void StaticShutdown();
 	static void StaticBootstrap();
@@ -678,9 +678,9 @@ class PClassType : public PClass
 {
 	DECLARE_CLASS(PClassType, PClass);
 protected:
-	virtual void Derive(PClass *newclass);
 public:
 	PClassType();
+	virtual void Derive(PClass *newclass);
 
 	PClass *TypeTableType;	// The type to use for hashing into the type table
 };
diff --git a/src/g_shared/a_pickups.cpp b/src/g_shared/a_pickups.cpp
index f6bca1294..4a73212aa 100644
--- a/src/g_shared/a_pickups.cpp
+++ b/src/g_shared/a_pickups.cpp
@@ -30,15 +30,37 @@ PClassInventory::PClassInventory()
 	AltHUDIcon.SetNull();
 }
 
-void PClassInventory::Derive(PClass *newclass)
+void PClassInventory::DeriveData(PClass *newclass)
 {
 	assert(newclass->IsKindOf(RUNTIME_CLASS(PClassInventory)));
-	Super::Derive(newclass);
+	Super::DeriveData(newclass);
 	PClassInventory *newc = static_cast<PClassInventory *>(newclass);
 
 	newc->PickupMessage = PickupMessage;
 	newc->GiveQuest = GiveQuest;
 	newc->AltHUDIcon = AltHUDIcon;
+	newc->ForbiddenToPlayerClass = ForbiddenToPlayerClass;
+	newc->RestrictedToPlayerClass = RestrictedToPlayerClass;
+}
+
+void PClassInventory::ReplaceClassRef(PClass *oldclass, PClass *newclass)
+{
+	Super::ReplaceClassRef(oldclass, newclass);
+	AInventory *def = (AInventory*)Defaults;
+	if (def != NULL)
+	{
+		if (def->PickupFlash == oldclass) def->PickupFlash = static_cast<PClassActor *>(newclass);
+		for (unsigned i = 0; i < ForbiddenToPlayerClass.Size(); i++)
+		{
+			if (ForbiddenToPlayerClass[i] == oldclass)
+				ForbiddenToPlayerClass[i] = static_cast<PClassPlayerPawn*>(newclass);
+		}
+		for (unsigned i = 0; i < RestrictedToPlayerClass.Size(); i++)
+		{
+			if (RestrictedToPlayerClass[i] == oldclass)
+				RestrictedToPlayerClass[i] = static_cast<PClassPlayerPawn*>(newclass);
+		}
+	}
 }
 
 IMPLEMENT_CLASS(PClassAmmo)
@@ -48,10 +70,10 @@ PClassAmmo::PClassAmmo()
 	DropAmount = 0;
 }
 
-void PClassAmmo::Derive(PClass *newclass)
+void PClassAmmo::DeriveData(PClass *newclass)
 {
 	assert(newclass->IsKindOf(RUNTIME_CLASS(PClassAmmo)));
-	Super::Derive(newclass);
+	Super::DeriveData(newclass);
 	PClassAmmo *newc = static_cast<PClassAmmo *>(newclass);
 
 	newc->DropAmount = DropAmount;
@@ -1524,7 +1546,7 @@ bool AInventory::CanPickup (AActor *toucher)
 	if (!toucher)
 		return false;
 
-	PClassActor *ai = GetClass();
+	PClassInventory *ai = GetClass();
 	// Is the item restricted to certain player classes?
 	if (ai->RestrictedToPlayerClass.Size() != 0)
 	{
@@ -1672,10 +1694,10 @@ PClassHealth::PClassHealth()
 //
 //===========================================================================
 
-void PClassHealth::Derive(PClass *newclass)
+void PClassHealth::DeriveData(PClass *newclass)
 {
 	assert(newclass->IsKindOf(RUNTIME_CLASS(PClassHealth)));
-	Super::Derive(newclass);
+	Super::DeriveData(newclass);
 	PClassHealth *newc = static_cast<PClassHealth *>(newclass);
 	
 	newc->LowHealth = LowHealth;
diff --git a/src/g_shared/a_pickups.h b/src/g_shared/a_pickups.h
index ef693394a..10391e0c8 100644
--- a/src/g_shared/a_pickups.h
+++ b/src/g_shared/a_pickups.h
@@ -135,14 +135,16 @@ enum
 class PClassInventory : public PClassActor
 {
 	DECLARE_CLASS(PClassInventory, PClassActor)
-protected:
-	virtual void Derive(PClass *newclass);
 public:
 	PClassInventory();
+	virtual void DeriveData(PClass *newclass);
+	virtual void ReplaceClassRef(PClass *oldclass, PClass *newclass);
 
 	FString PickupMessage;
 	int GiveQuest;			// Optionally give one of the quest items.
 	FTextureID AltHUDIcon;
+	TArray<PClassPlayerPawn *> RestrictedToPlayerClass;
+	TArray<PClassPlayerPawn *> ForbiddenToPlayerClass;
 };
 
 class AInventory : public AActor
@@ -241,7 +243,7 @@ class PClassAmmo : public PClassInventory
 {
 	DECLARE_CLASS(PClassAmmo, PClassInventory)
 protected:
-	virtual void Derive(PClass *newclass);
+	virtual void DeriveData(PClass *newclass);
 public:
 	PClassAmmo();
 
@@ -266,9 +268,10 @@ class PClassWeapon : public PClassInventory
 {
 	DECLARE_CLASS(PClassWeapon, PClassInventory);
 protected:
-	virtual void Derive(PClass *newclass);
+	virtual void DeriveData(PClass *newclass);
 public:
 	PClassWeapon();
+	virtual void ReplaceClassRef(PClass *oldclass, PClass *newclass);
 
 	int SlotNumber;
 	fixed_t SlotPriority;
@@ -401,9 +404,9 @@ class PClassHealth : public PClassInventory
 {
 	DECLARE_CLASS(PClassHealth, PClassInventory)
 protected:
-	virtual void Derive(PClass *newclass);
 public:
 	PClassHealth();
+	virtual void DeriveData(PClass *newclass);
 
 	FString LowHealthMessage;
 	int LowHealth;
@@ -518,8 +521,8 @@ class PClassPuzzleItem : public PClassInventory
 {
 	DECLARE_CLASS(PClassPuzzleItem, PClassInventory);
 protected:
-	virtual void Derive(PClass *newclass);
 public:
+	virtual void DeriveData(PClass *newclass);
 	FString PuzzFailMessage;
 };
 
diff --git a/src/g_shared/a_puzzleitems.cpp b/src/g_shared/a_puzzleitems.cpp
index 0d60ab829..837ac3463 100644
--- a/src/g_shared/a_puzzleitems.cpp
+++ b/src/g_shared/a_puzzleitems.cpp
@@ -11,9 +11,9 @@
 
 IMPLEMENT_CLASS(PClassPuzzleItem)
 
-void PClassPuzzleItem::Derive(PClass *newclass)
+void PClassPuzzleItem::DeriveData(PClass *newclass)
 {
-	Super::Derive(newclass);
+	Super::DeriveData(newclass);
 	assert(newclass->IsKindOf(RUNTIME_CLASS(PClassPuzzleItem)));
 	static_cast<PClassPuzzleItem *>(newclass)->PuzzFailMessage = PuzzFailMessage;
 }
diff --git a/src/g_shared/a_weaponpiece.cpp b/src/g_shared/a_weaponpiece.cpp
index 6862c1911..1a4c27882 100644
--- a/src/g_shared/a_weaponpiece.cpp
+++ b/src/g_shared/a_weaponpiece.cpp
@@ -3,8 +3,20 @@
 #include "doomstat.h"
 #include "farchive.h"
 
+IMPLEMENT_CLASS(PClassWeaponPiece)
 IMPLEMENT_CLASS (AWeaponHolder)
 
+void PClassWeaponPiece::ReplaceClassRef(PClass *oldclass, PClass *newclass)
+{
+	Super::ReplaceClassRef(oldclass, newclass);
+	AWeaponPiece *def = (AWeaponPiece*)Defaults;
+	if (def != NULL)
+	{
+		if (def->WeaponClass == oldclass) def->WeaponClass = static_cast<PClassWeapon *>(newclass);
+	}
+}
+
+
 void AWeaponHolder::Serialize (FArchive &arc)
 {
 	Super::Serialize(arc);
diff --git a/src/g_shared/a_weaponpiece.h b/src/g_shared/a_weaponpiece.h
index 9f495a06e..dfa30f5d7 100644
--- a/src/g_shared/a_weaponpiece.h
+++ b/src/g_shared/a_weaponpiece.h
@@ -1,7 +1,16 @@
 
+// Ammo: Something a weapon needs to operate
+class PClassWeaponPiece : public PClassInventory
+{
+	DECLARE_CLASS(PClassWeaponPiece, PClassInventory)
+protected:
+public:
+	virtual void ReplaceClassRef(PClass *oldclass, PClass *newclass);
+};
+
 class AWeaponPiece : public AInventory
 {
-	DECLARE_CLASS (AWeaponPiece, AInventory)
+	DECLARE_CLASS_WITH_META(AWeaponPiece, AInventory, PClassWeaponPiece)
 	HAS_OBJECT_POINTERS
 protected:
 	bool PrivateShouldStay ();
diff --git a/src/g_shared/a_weapons.cpp b/src/g_shared/a_weapons.cpp
index c972c7120..09ab0ffd8 100644
--- a/src/g_shared/a_weapons.cpp
+++ b/src/g_shared/a_weapons.cpp
@@ -44,16 +44,29 @@ PClassWeapon::PClassWeapon()
 	SlotPriority = FIXED_MAX;
 }
 
-void PClassWeapon::Derive(PClass *newclass)
+void PClassWeapon::DeriveData(PClass *newclass)
 {
 	assert(newclass->IsKindOf(RUNTIME_CLASS(PClassWeapon)));
-	Super::Derive(newclass);
+	Super::DeriveData(newclass);
 	PClassWeapon *newc = static_cast<PClassWeapon *>(newclass);
 
 	newc->SlotNumber = SlotNumber;
 	newc->SlotPriority = SlotPriority;
 }
 
+
+void PClassWeapon::ReplaceClassRef(PClass *oldclass, PClass *newclass)
+{
+	Super::ReplaceClassRef(oldclass, newclass);
+	AWeapon *def = (AWeapon*)Defaults;
+	if (def != NULL)
+	{
+		if (def->AmmoType1 == oldclass) def->AmmoType1 = static_cast<PClassAmmo *>(newclass);
+		if (def->AmmoType2 == oldclass) def->AmmoType2 = static_cast<PClassAmmo *>(newclass);
+		if (def->SisterWeaponType == oldclass) def->SisterWeaponType = static_cast<PClassWeapon *>(newclass);
+	}
+}
+
 //===========================================================================
 //
 // AWeapon :: Serialize
diff --git a/src/info.cpp b/src/info.cpp
index 8c2ae06a6..3a800e2cf 100644
--- a/src/info.cpp
+++ b/src/info.cpp
@@ -201,16 +201,11 @@ PClassActor::PClassActor()
 	FastSpeed = FIXED_MIN;
 	RDFactor = FRACUNIT;
 	CameraHeight = FIXED_MIN;
-	BloodType = NAME_Blood;
-	BloodType2 = NAME_BloodSplatter;
-	BloodType3 = NAME_AxeBlood;
 
 	DropItems = NULL;
 
 	DontHurtShooter = false;
-	ExplosionDamage = 128;
 	ExplosionRadius = -1;
-	MissileHeight = 32*FRACUNIT;
 	MeleeDamage = 0;
 
 	// Record this in the master list.
@@ -250,10 +245,9 @@ PClassActor::~PClassActor()
 //
 //==========================================================================
 
-void PClassActor::Derive(PClass *newclass)
+void PClassActor::DeriveData(PClass *newclass)
 {
 	assert(newclass->IsKindOf(RUNTIME_CLASS(PClassActor)));
-	Super::Derive(newclass);
 	PClassActor *newa = static_cast<PClassActor *>(newclass);
 
 	newa->Obituary = Obituary;
@@ -281,6 +275,22 @@ void PClassActor::Derive(PClass *newclass)
 	newa->MeleeSound = MeleeSound;
 	newa->MissileName = MissileName;
 	newa->MissileHeight = MissileHeight;
+
+	newa->VisibleToPlayerClass = VisibleToPlayerClass;
+
+	if (DamageFactors != NULL)
+	{
+		// copy damage factors from parent
+		newa->DamageFactors = new DmgFactors;
+		*newa->DamageFactors = *DamageFactors;
+	}
+	if (PainChances != NULL)
+	{
+		// copy pain chances from parent
+		newa->PainChances = new PainChanceList;
+		*newa->PainChances = *PainChances;
+	}
+
 }
 
 //==========================================================================
@@ -522,6 +532,27 @@ void PClassActor::SetPainChance(FName type, int chance)
 	}
 }
 
+//==========================================================================
+//
+// PClassActor :: ReplaceClassRef
+//
+//==========================================================================
+
+void PClassActor::ReplaceClassRef(PClass *oldclass, PClass *newclass)
+{
+	for (unsigned i = 0; i < VisibleToPlayerClass.Size(); i++)
+	{
+		if (VisibleToPlayerClass[i] == oldclass)
+			VisibleToPlayerClass[i] = static_cast<PClassPlayerPawn*>(newclass);
+	}
+	AActor *def = (AActor*)Defaults;
+	if (def != NULL)
+	{
+		if (def->TeleFogSourceType == oldclass) def->TeleFogSourceType = static_cast<PClassActor *>(newclass);
+		if (def->TeleFogDestType == oldclass) def->TeleFogDestType = static_cast<PClassActor *>(newclass);
+	}
+}
+
 //==========================================================================
 //
 // DmgFactors :: CheckFactor
diff --git a/src/info.h b/src/info.h
index 2d0c627ec..460adb0fb 100644
--- a/src/info.h
+++ b/src/info.h
@@ -192,14 +192,15 @@ class PClassActor : public PClass
 	DECLARE_CLASS(PClassActor, PClass);
 	HAS_OBJECT_POINTERS;
 protected:
-	virtual void Derive(PClass *newclass);
 public:
 	static void StaticInit ();
 	static void StaticSetActorNums ();
+	virtual void DeriveData(PClass *newclass);
 
 	PClassActor();
 	~PClassActor();
 
+	virtual void ReplaceClassRef(PClass *oldclass, PClass *newclass);
 	void BuildDefaults();
 	void ApplyDefaults(BYTE *defaults);
 	void RegisterIDs();
@@ -236,8 +237,6 @@ public:
 	PainChanceList *PainChances;
 
 	TArray<PClassPlayerPawn *> VisibleToPlayerClass;
-	TArray<PClassPlayerPawn *> RestrictedToPlayerClass;
-	TArray<PClassPlayerPawn *> ForbiddenToPlayerClass;
 
 	FString Obituary;		// Player was killed by this actor
 	FString HitObituary;	// Player was killed by this actor in melee
diff --git a/src/p_user.cpp b/src/p_user.cpp
index 0427bd64f..59098e83a 100644
--- a/src/p_user.cpp
+++ b/src/p_user.cpp
@@ -515,10 +515,10 @@ PClassPlayerPawn::PClassPlayerPawn()
 	ColorRangeEnd = 0;
 }
 
-void PClassPlayerPawn::Derive(PClass *newclass)
+void PClassPlayerPawn::DeriveData(PClass *newclass)
 {
 	assert(newclass->IsKindOf(RUNTIME_CLASS(PClassPlayerPawn)));
-	Super::Derive(newclass);
+	Super::DeriveData(newclass);
 	PClassPlayerPawn *newp = static_cast<PClassPlayerPawn *>(newclass);
 	size_t i;
 
@@ -581,6 +581,16 @@ bool PClassPlayerPawn::GetPainFlash(FName type, PalEntry *color) const
 	return false;
 }
 
+void PClassPlayerPawn::ReplaceClassRef(PClass *oldclass, PClass *newclass)
+{
+	Super::ReplaceClassRef(oldclass, newclass);
+	APlayerPawn *def = (APlayerPawn*)Defaults;
+	if (def != NULL)
+	{
+		if (def->FlechetteType == oldclass) def->FlechetteType = static_cast<PClassInventory *>(newclass);
+	}
+}
+
 //===========================================================================
 //
 // player_t :: SendPitchLimits
diff --git a/src/thingdef/thingdef.cpp b/src/thingdef/thingdef.cpp
index b12f45abe..a85f0ea08 100644
--- a/src/thingdef/thingdef.cpp
+++ b/src/thingdef/thingdef.cpp
@@ -137,6 +137,7 @@ PClassActor *CreateNewActor(const FScriptPosition &sc, FName typeName, FName par
 			goto create;
 		}
 		ti->InitializeNativeDefaults();
+		ti->ParentClass->DeriveData(ti);
 	}
 	else
 	{
@@ -144,23 +145,6 @@ PClassActor *CreateNewActor(const FScriptPosition &sc, FName typeName, FName par
 		ti = static_cast<PClassActor *>(parent->CreateDerivedClass (typeName, parent->Size));
 	}
 
-	// Copy class lists from parent
-	ti->ForbiddenToPlayerClass = parent->ForbiddenToPlayerClass;
-	ti->RestrictedToPlayerClass = parent->RestrictedToPlayerClass;
-	ti->VisibleToPlayerClass = parent->VisibleToPlayerClass;
-
-	if (parent->DamageFactors != NULL)
-	{
-		// copy damage factors from parent
-		ti->DamageFactors = new DmgFactors;
-		*ti->DamageFactors = *parent->DamageFactors;
-	}
-	if (parent->PainChances != NULL)
-	{
-		// copy pain chances from parent
-		ti->PainChances = new PainChanceList;
-		*ti->PainChances = *parent->PainChances;
-	}
 	ti->Replacee = ti->Replacement = NULL;
 	ti->DoomEdNum = -1;
 	return ti;
@@ -340,15 +324,10 @@ static void FinishThingdef()
 	{
 		PClassActor *ti = PClassActor::AllActorClasses[i];
 
-		if (ti->Size == TClass_Fatal || ti->Size == TClass_Nonfatal)
+		if (ti->Size == TentativeClass)
 		{
 			Printf(TEXTCOLOR_RED "Class %s referenced but not defined\n", ti->TypeName.GetChars());
-			if (ti->Size == TClass_Fatal) errorcount++;
-			else
-			{
-				// In order to prevent a crash, this class needs to be completed, even though it defines nothing.
-				ti->ParentClass->CreateDerivedClass(ti->TypeName, ti->ParentClass->Size);
-			}
+			errorcount++;
 			continue;
 		}
 
diff --git a/src/thingdef/thingdef_exp.cpp b/src/thingdef/thingdef_exp.cpp
index e198ec20b..e8a043d31 100644
--- a/src/thingdef/thingdef_exp.cpp
+++ b/src/thingdef/thingdef_exp.cpp
@@ -72,12 +72,15 @@ static FxExpression *ParseExpressionB (FScanner &sc, PClassActor *cls);
 static FxExpression *ParseExpressionA (FScanner &sc, PClassActor *cls);
 static FxExpression *ParseExpression0 (FScanner &sc, PClassActor *cls);
 
-FxExpression *ParseExpression (FScanner &sc, PClassActor *cls)
+FxExpression *ParseExpression (FScanner &sc, PClassActor *cls, bool mustresolve)
 {
 	FxExpression *data = ParseExpressionM (sc, cls);
 
-	FCompileContext ctx(cls);
-	data = data->Resolve(ctx);
+	if (mustresolve)
+	{
+		FCompileContext ctx(cls);
+		data = data->Resolve(ctx);
+	}
 
 	return data;
 }
diff --git a/src/thingdef/thingdef_exp.h b/src/thingdef/thingdef_exp.h
index 6dd11a681..f81dd2b54 100644
--- a/src/thingdef/thingdef_exp.h
+++ b/src/thingdef/thingdef_exp.h
@@ -984,7 +984,7 @@ public:
 };
 
 
-FxExpression *ParseExpression (FScanner &sc, PClassActor *cls);
+FxExpression *ParseExpression (FScanner &sc, PClassActor *cls, bool mustresolve = false);
 
 
 #endif
diff --git a/src/thingdef/thingdef_expression.cpp b/src/thingdef/thingdef_expression.cpp
index b86c690f5..8b2c52405 100644
--- a/src/thingdef/thingdef_expression.cpp
+++ b/src/thingdef/thingdef_expression.cpp
@@ -52,6 +52,7 @@
 #include "thingdef_exp.h"
 #include "m_fixed.h"
 #include "vmbuilder.h"
+#include "v_text.h"
 
 ExpEmit::ExpEmit(VMFunctionBuilder *build, int type)
 : RegNum(build->Registers[type].Get(1)), RegType(type), Konst(false), Fixed(false)
@@ -3546,15 +3547,25 @@ FxExpression *FxClassTypeCast::Resolve(FCompileContext &ctx)
 
 		if (clsname != NAME_None)
 		{
-			// for backwards compatibility with old times it cannot be made a fatal error, if the class is not defined. :(
-			cls = desttype->FindClassTentative(clsname, false);
-			if (!cls->IsDescendantOf(desttype))
+			cls = PClass::FindClass(clsname);
+			if (cls == NULL)
 			{
-				ScriptPosition.Message(MSG_ERROR,"class '%s' is not compatible with '%s'", clsname.GetChars(), desttype->TypeName.GetChars());
-				delete this;
-				return NULL;
+				/* lax */
+				// Since this happens in released WADs it must pass without a terminal error... :(
+				ScriptPosition.Message(MSG_WARNING,
+					"Unknown class name '%s'",
+					clsname.GetChars(), desttype->TypeName.GetChars());
+			}
+			else
+			{
+				if (!cls->IsDescendantOf(desttype))
+				{
+					ScriptPosition.Message(MSG_ERROR, "class '%s' is not compatible with '%s'", clsname.GetChars(), desttype->TypeName.GetChars());
+					delete this;
+					return NULL;
+				}
+				ScriptPosition.Message(MSG_DEBUG, "resolving '%s' as class name", clsname.GetChars());
 			}
-			ScriptPosition.Message(MSG_DEBUG,"resolving '%s' as class name", clsname.GetChars());
 		}
 		FxExpression *x = new FxConstant(cls, ScriptPosition);
 		delete this;
diff --git a/src/thingdef/thingdef_parse.cpp b/src/thingdef/thingdef_parse.cpp
index 1db878bfa..cf76fb10b 100644
--- a/src/thingdef/thingdef_parse.cpp
+++ b/src/thingdef/thingdef_parse.cpp
@@ -79,7 +79,7 @@ FxExpression *ParseParameter(FScanner &sc, PClassActor *cls, PType *type, bool c
 	}
 	else if (type == TypeSInt32 || type == TypeFloat64)
 	{
-		x = ParseExpression (sc, cls);
+		x = ParseExpression (sc, cls, constant);
 		if (constant && !x->isConstant())
 		{
 			sc.ScriptMessage("Default parameter must be constant.");
@@ -190,7 +190,7 @@ static void ParseConstant (FScanner &sc, PSymbolTable *symt, PClassActor *cls)
 		sc.MustGetToken(TK_Identifier);
 		FName symname = sc.String;
 		sc.MustGetToken('=');
-		FxExpression *expr = ParseExpression (sc, cls);
+		FxExpression *expr = ParseExpression (sc, cls, true);
 		sc.MustGetToken(';');
 
 		if (!expr->isConstant())
@@ -248,7 +248,7 @@ static void ParseEnum (FScanner &sc, PSymbolTable *symt, PClassActor *cls)
 		FName symname = sc.String;
 		if (sc.CheckToken('='))
 		{
-			FxExpression *expr = ParseExpression (sc, cls);
+			FxExpression *expr = ParseExpression (sc, cls, true);
 			if (!expr->isConstant())
 			{
 				sc.ScriptMessage("'%s' must be constant", symname.GetChars());
@@ -536,7 +536,7 @@ static void ParseUserVariable (FScanner &sc, PSymbolTable *symt, PClassActor *cl
 
 	if (sc.CheckToken('['))
 	{
-		FxExpression *expr = ParseExpression(sc, cls);
+		FxExpression *expr = ParseExpression(sc, cls, true);
 		if (!expr->isConstant())
 		{
 			sc.ScriptMessage("Array size must be a constant");
diff --git a/src/thingdef/thingdef_properties.cpp b/src/thingdef/thingdef_properties.cpp
index cecdfb172..57de3684f 100644
--- a/src/thingdef/thingdef_properties.cpp
+++ b/src/thingdef/thingdef_properties.cpp
@@ -1534,12 +1534,12 @@ DEFINE_PROPERTY(riplevelmax, I, Actor)
 //==========================================================================
 DEFINE_CLASS_PROPERTY(restrictedto, Ssssssssssssssssssss, Inventory)
 {
-	info->RestrictedToPlayerClass.Clear();
+	static_cast<PClassInventory*>(info)->RestrictedToPlayerClass.Clear();
 	for(int i = 0;i < PROP_PARM_COUNT;++i)
 	{
 		PROP_STRING_PARM(n, i);
 		if (*n != 0)
-			info->RestrictedToPlayerClass.Push(FindClassTentativePlayerPawn(n));
+			static_cast<PClassInventory*>(info)->RestrictedToPlayerClass.Push(FindClassTentativePlayerPawn(n));
 	}
 }
 
@@ -1548,12 +1548,12 @@ DEFINE_CLASS_PROPERTY(restrictedto, Ssssssssssssssssssss, Inventory)
 //==========================================================================
 DEFINE_CLASS_PROPERTY(forbiddento, Ssssssssssssssssssss, Inventory)
 {
-	info->ForbiddenToPlayerClass.Clear();
+	static_cast<PClassInventory*>(info)->ForbiddenToPlayerClass.Clear();
 	for(int i = 0;i < PROP_PARM_COUNT;++i)
 	{
 		PROP_STRING_PARM(n, i);
 		if (*n != 0)
-			info->ForbiddenToPlayerClass.Push(FindClassTentativePlayerPawn(n));
+			static_cast<PClassInventory*>(info)->ForbiddenToPlayerClass.Push(FindClassTentativePlayerPawn(n));
 	}
 }
 
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index 8677cfb82..8a79dd170 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -32,6 +32,10 @@ ACTOR Actor native //: Thinker
 	RipLevelMin 0
 	RipLevelMax 0
 	DefThreshold 100
+	BloodType "Blood", "BloodSplatter", "AxeBlood"
+	ExplosionDamage 128
+	MissileHeight 32
+	
 
 	// Functions
 	native bool CheckClass(class<Actor> checkclass, int ptr_select = AAPTR_DEFAULT, bool match_superclass = false);