diff --git a/src/c_cmds.cpp b/src/c_cmds.cpp
index 988567995..23e2634dc 100644
--- a/src/c_cmds.cpp
+++ b/src/c_cmds.cpp
@@ -931,12 +931,12 @@ static bool IsActorAMonster(AActor *mo)
 
 static bool IsActorAnItem(AActor *mo)
 {
-	return mo->IsKindOf(RUNTIME_CLASS(AInventory)) && mo->flags&MF_SPECIAL;
+	return mo->IsKindOf(NAME_Inventory) && mo->flags&MF_SPECIAL;
 }
 
 static bool IsActorACountItem(AActor *mo)
 {
-	return mo->IsKindOf(RUNTIME_CLASS(AInventory)) && mo->flags&MF_SPECIAL && mo->flags&MF_COUNTITEM;
+	return mo->IsKindOf(NAME_Inventory) && mo->flags&MF_SPECIAL && mo->flags&MF_COUNTITEM;
 }
 
 // [SP] for all actors
diff --git a/src/d_dehacked.cpp b/src/d_dehacked.cpp
index 619ccc4a6..5b11431fa 100644
--- a/src/d_dehacked.cpp
+++ b/src/d_dehacked.cpp
@@ -3065,7 +3065,7 @@ void FinishDehPatch ()
 		FStateDefinitions statedef;
 		statedef.MakeStateDefines(type);
 
-		if (!type->IsDescendantOf(RUNTIME_CLASS(AInventory)))
+		if (!type->IsDescendantOf(NAME_Inventory))
 		{
 			// If this is a hacked non-inventory item we must also copy AInventory's special states
 			statedef.AddStateDefines(RUNTIME_CLASS(AInventory)->GetStateLabels());
diff --git a/src/fragglescript/t_func.cpp b/src/fragglescript/t_func.cpp
index ac2fb8dfa..2e6ccc5ee 100644
--- a/src/fragglescript/t_func.cpp
+++ b/src/fragglescript/t_func.cpp
@@ -3669,7 +3669,7 @@ void FParser::SF_ThingCount(void)
 again:
 		TThinkerIterator<AActor> it;
 
-		if (t_argc<2 || intvalue(t_argv[1])==0 || pClass->IsDescendantOf(RUNTIME_CLASS(AInventory)))
+		if (t_argc<2 || intvalue(t_argv[1])==0 || pClass->IsDescendantOf(NAME_Inventory))
 		{
 			while ((mo=it.Next()))
 			{
diff --git a/src/g_inventory/a_keys.cpp b/src/g_inventory/a_keys.cpp
index 845131706..0e5e2a8bd 100644
--- a/src/g_inventory/a_keys.cpp
+++ b/src/g_inventory/a_keys.cpp
@@ -182,7 +182,7 @@ static void AddOneKey(Keygroup *keygroup, PClassActor *mi, FScanner &sc)
 	if (mi)
 	{
 		// Any inventory item can be used to unlock a door
-		if (mi->IsDescendantOf(RUNTIME_CLASS(AInventory)))
+		if (mi->IsDescendantOf(NAME_Inventory))
 		{
 			OneKey k = {mi,1};
 			keygroup->anykeylist.Push (k);
diff --git a/src/g_shared/a_specialspot.cpp b/src/g_shared/a_specialspot.cpp
index cdf3742ca..1484e3def 100644
--- a/src/g_shared/a_specialspot.cpp
+++ b/src/g_shared/a_specialspot.cpp
@@ -455,7 +455,7 @@ DEFINE_ACTION_FUNCTION(ASpecialSpot, A_SpawnSingleItem)
 		{
 			spawned->flags &= ~MF_DROPPED;
 		}
-		if (spawned->IsKindOf(RUNTIME_CLASS(AInventory)))
+		if (spawned->IsKindOf(NAME_Inventory))
 		{
 			static_cast<AInventory*>(spawned)->SpawnPointClass = self->GetClass();
 		}
diff --git a/src/gl/scene/gl_sprite.cpp b/src/gl/scene/gl_sprite.cpp
index d9976cbeb..ff74017a3 100644
--- a/src/gl/scene/gl_sprite.cpp
+++ b/src/gl/scene/gl_sprite.cpp
@@ -584,7 +584,7 @@ void GLSprite::SplitSprite(sector_t * frontsector, bool translucent)
 void GLSprite::PerformSpriteClipAdjustment(AActor *thing, const DVector2 &thingpos, float spriteheight)
 {
 	const float NO_VAL = 100000000.0f;
-	bool clipthing = (thing->player || thing->flags3&MF3_ISMONSTER || thing->IsKindOf(RUNTIME_CLASS(AInventory))) && (thing->flags&MF_ICECORPSE || !(thing->flags&MF_CORPSE));
+	bool clipthing = (thing->player || thing->flags3&MF3_ISMONSTER || thing->IsKindOf(NAME_Inventory)) && (thing->flags&MF_ICECORPSE || !(thing->flags&MF_CORPSE));
 	bool smarterclip = !clipthing && gl_spriteclip == 3;
 	if (clipthing || gl_spriteclip > 1)
 	{
diff --git a/src/info.cpp b/src/info.cpp
index c02767c44..76eb20ce9 100644
--- a/src/info.cpp
+++ b/src/info.cpp
@@ -346,7 +346,7 @@ static void LoadAltHudStuff()
 				{
 					Printf("Unknown item class '%s' in ALTHUDCF\n", sc.String);
 				}
-				else if (!ti->IsDescendantOf(RUNTIME_CLASS(AInventory)))
+				else if (!ti->IsDescendantOf(NAME_Inventory))
 				{
 					Printf("Invalid item class '%s' in ALTHUDCF\n", sc.String);
 					ti = NULL;
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index d0e8f9713..95a9b71db 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -1846,7 +1846,7 @@ static int CheckInventory (AActor *activator, const char *type, bool max)
 		DPrintf (DMSG_ERROR, "ACS: '%s': Unknown actor class.\n", type);
 		return 0;
 	}
-	else if (!info->IsDescendantOf(RUNTIME_CLASS(AInventory)))
+	else if (!info->IsDescendantOf(NAME_Inventory))
 	{
 		DPrintf(DMSG_ERROR, "ACS: '%s' is not an inventory item.\n", type);
 		return 0;
@@ -1860,7 +1860,7 @@ static int CheckInventory (AActor *activator, const char *type, bool max)
 		{
 			return item->MaxAmount;
 		}
-		else if (info != nullptr && info->IsDescendantOf(RUNTIME_CLASS(AInventory)))
+		else if (info != nullptr && info->IsDescendantOf(NAME_Inventory))
 		{
 			return ((AInventory *)GetDefaultByType(info))->MaxAmount;
 		}
diff --git a/src/p_actionfunctions.cpp b/src/p_actionfunctions.cpp
index d8cf5a57e..d36c8f218 100644
--- a/src/p_actionfunctions.cpp
+++ b/src/p_actionfunctions.cpp
@@ -4062,7 +4062,7 @@ static bool DoRadiusGive(AActor *self, AActor *thing, PClassActor *item, int amo
 			return false;
 		doPass = true;
 	}
-	else if (((flags & RGF_ITEMS) && thing->IsKindOf(RUNTIME_CLASS(AInventory))) ||
+	else if (((flags & RGF_ITEMS) && thing->IsKindOf(NAME_Inventory)) ||
 			((flags & RGF_CORPSES) && thing->flags & MF_CORPSE) ||
 			((flags & RGF_KILLED) && thing->flags6 & MF6_KILLED))
 	{
diff --git a/src/p_conversation.cpp b/src/p_conversation.cpp
index 058e2e6d7..93182e51c 100644
--- a/src/p_conversation.cpp
+++ b/src/p_conversation.cpp
@@ -380,7 +380,7 @@ static FStrifeDialogueNode *ReadRetailNode (FileReader &lump, uint32_t &prevSpea
 	for (j = 0; j < 3; ++j)
 	{
 		auto inv = GetStrifeType(speech.ItemCheck[j]);
-		if (!inv->IsDescendantOf(RUNTIME_CLASS(AInventory))) inv = nullptr;
+		if (!inv->IsDescendantOf(NAME_Inventory)) inv = nullptr;
 		node->ItemCheck[j].Item = inv;
 		node->ItemCheck[j].Amount = -1;
 	}
@@ -526,7 +526,7 @@ static void ParseReplies (FStrifeDialogueReply **replyptr, Response *responses)
 		for (k = 0; k < 3; ++k)
 		{
 			auto inv = GetStrifeType(rsp->Item[k]);
-			if (!inv->IsDescendantOf(RUNTIME_CLASS(AInventory))) inv = nullptr;
+			if (!inv->IsDescendantOf(NAME_Inventory)) inv = nullptr;
 			reply->ItemCheck[k].Item = inv;
 			reply->ItemCheck[k].Amount = rsp->Count[k];
 		}
@@ -958,7 +958,7 @@ static void HandleReply(player_t *player, bool isconsole, int nodenum, int reply
 	takestuff = true;
 	if (reply->GiveType != NULL)
 	{
-		if (reply->GiveType->IsDescendantOf(RUNTIME_CLASS(AInventory)))
+		if (reply->GiveType->IsDescendantOf(NAME_Inventory))
 		{
 			if (reply->GiveType->IsDescendantOf(NAME_Weapon))
 			{
diff --git a/src/p_map.cpp b/src/p_map.cpp
index f9cfdaed6..e50e7e527 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -552,7 +552,7 @@ bool	P_TeleportMove(AActor* thing, const DVector3 &pos, bool telefrag, bool modi
 			continue;
 
 		// Don't let players and monsters block item teleports (all other actor types will still block.)
-		if (thing->IsKindOf(RUNTIME_CLASS(AInventory)) && !(thing->flags & MF_SOLID) && ((th->flags3 & MF3_ISMONSTER) || th->player != nullptr))
+		if (thing->IsKindOf(NAME_Inventory) && !(thing->flags & MF_SOLID) && ((th->flags3 & MF3_ISMONSTER) || th->player != nullptr))
 			continue;
 
 		// monsters don't stomp things except on boss level
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 45ef4b2be..7619a5ae6 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -636,7 +636,7 @@ DEFINE_ACTION_FUNCTION(AActor, InStateSequence)
 bool AActor::IsMapActor()
 {
 	// [SP] Don't remove owned inventory objects.
-	return (!IsKindOf(RUNTIME_CLASS(AInventory)) || static_cast<AInventory *>(this)->Owner == nullptr);
+	return (!IsKindOf(NAME_Inventory) || static_cast<AInventory *>(this)->Owner == nullptr);
 }
 
 //==========================================================================
diff --git a/src/p_usdf.cpp b/src/p_usdf.cpp
index 01c091de9..9774371e5 100644
--- a/src/p_usdf.cpp
+++ b/src/p_usdf.cpp
@@ -78,7 +78,7 @@ class USDFParser : public UDMFParserBase
 	PClassActor *CheckInventoryActorType(const char *key)
 	{
 		PClassActor* const type = CheckActorType(key);
-		return nullptr != type && type->IsDescendantOf(RUNTIME_CLASS(AInventory)) ? type : nullptr;
+		return nullptr != type && type->IsDescendantOf(NAME_Inventory) ? type : nullptr;
 	}
 
 	//===========================================================================
diff --git a/src/polyrenderer/scene/poly_sprite.cpp b/src/polyrenderer/scene/poly_sprite.cpp
index 4e1e8f89a..c50d2ed82 100644
--- a/src/polyrenderer/scene/poly_sprite.cpp
+++ b/src/polyrenderer/scene/poly_sprite.cpp
@@ -225,7 +225,7 @@ double RenderPolySprite::PerformSpriteClipAdjustment(AActor *thing, const DVecto
 	if (!(spriteheight > 0 && spriteclip > 0 && spritetype == RF_FACESPRITE))
 		return z2;
 
-	bool clipthing = (thing->player || thing->flags3&MF3_ISMONSTER || thing->IsKindOf(RUNTIME_CLASS(AInventory))) && (thing->flags&MF_ICECORPSE || !(thing->flags&MF_CORPSE));
+	bool clipthing = (thing->player || thing->flags3&MF3_ISMONSTER || thing->IsKindOf(NAME_Inventory)) && (thing->flags&MF_ICECORPSE || !(thing->flags&MF_CORPSE));
 	bool smarterclip = !clipthing && spriteclip == 3;
 	if (clipthing || spriteclip > 1)
 	{