diff --git a/src/d_dehacked.cpp b/src/d_dehacked.cpp
index 71deb01691..97d15e4d0d 100644
--- a/src/d_dehacked.cpp
+++ b/src/d_dehacked.cpp
@@ -808,22 +808,23 @@ void SetDehParams(FState *state, int codepointer)
 	else
 	{
 		VMFunctionBuilder buildit(true);
+		int numargs = sym->GetImplicitArgs();
 		// Allocate registers used to pass parameters in.
 		// self, stateowner, state (all are pointers)
-		buildit.Registers[REGT_POINTER].Get(NAP);
+		buildit.Registers[REGT_POINTER].Get(numargs);
 		// Emit code to pass the standard action function parameters.
-		for (int i = 0; i < NAP; i++)
+		for (int i = 0; i < numargs; i++)
 		{
 			buildit.Emit(OP_PARAM, 0, REGT_POINTER, i);
 		}
 		// Emit code for action parameters.
 		int argcount = MBFCodePointerFactories[codepointer](buildit, value1, value2);
-		buildit.Emit(OP_TAIL_K, buildit.GetConstantAddress(sym->Variants[0].Implementation, ATAG_OBJECT), NAP + argcount, 0);
+		buildit.Emit(OP_TAIL_K, buildit.GetConstantAddress(sym->Variants[0].Implementation, ATAG_OBJECT), numargs + argcount, 0);
 		// Attach it to the state.
 		VMScriptFunction *sfunc = new VMScriptFunction;
 		buildit.MakeFunction(sfunc);
-		sfunc->NumArgs = NAP;
-		sfunc->ImplicitArgs = NAP;
+		sfunc->NumArgs = numargs;
+		sfunc->ImplicitArgs = numargs;
 		state->SetAction(sfunc);
 		sfunc->PrintableName.Format("Dehacked.%s.%d.%d", MBFCodePointers[codepointer].name.GetChars(), value1, value2);
 	}
@@ -2121,7 +2122,8 @@ static int PatchCodePtrs (int dummy)
 				else
 				{
 					TArray<DWORD> &args = sym->Variants[0].ArgFlags;
-					if ((sym->Variants[0].Flags & (VARF_Method | VARF_Action)) != (VARF_Method | VARF_Action) || (args.Size() > NAP && !(args[NAP] & VARF_Optional)))
+					unsigned numargs = sym->GetImplicitArgs();
+					if ((sym->Variants[0].Flags & VARF_Virtual || (args.Size() > numargs && !(args[numargs] & VARF_Optional))))
 					{
 						Printf("Frame %d: Incompatible code pointer '%s'\n", frame, Line2);
 						sym = NULL;
@@ -2733,7 +2735,8 @@ static bool LoadDehSupp ()
 						else
 						{
 							TArray<DWORD> &args = sym->Variants[0].ArgFlags;
-							if ((sym->Variants[0].Flags & (VARF_Method|VARF_Action)) != (VARF_Method | VARF_Action) || (args.Size() > NAP && !(args[NAP] & VARF_Optional)))
+							unsigned numargs = sym->GetImplicitArgs();
+							if ((sym->Variants[0].Flags & VARF_Virtual || (args.Size() > numargs && !(args[numargs] & VARF_Optional))))
 							{
 								sc.ScriptMessage("Incompatible code pointer '%s'", sc.String);
 							}
diff --git a/src/p_enemy.cpp b/src/p_enemy.cpp
index 1a2bddda49..14ea2b7c1e 100644
--- a/src/p_enemy.cpp
+++ b/src/p_enemy.cpp
@@ -2773,7 +2773,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_Chase)
 	PARAM_STATE_OPT	(missile)	{ missile = NULL; }
 	PARAM_INT_OPT	(flags)		{ flags = 0; }
 
-	if (numparam >= NAP + 1)
+	if (numparam > 1)
 	{
 		if ((flags & CHF_RESURRECT) && P_CheckForResurrection(self, false))
 			return 0;
diff --git a/src/scripting/decorate/thingdef_states.cpp b/src/scripting/decorate/thingdef_states.cpp
index 8b75b935f4..dda25f9265 100644
--- a/src/scripting/decorate/thingdef_states.cpp
+++ b/src/scripting/decorate/thingdef_states.cpp
@@ -38,7 +38,7 @@
 **
 */
 
-#include "actor.h"
+#include "a_pickups.h"
 #include "info.h"
 #include "sc_man.h"
 #include "tarray.h"
@@ -602,16 +602,16 @@ void ParseFunctionParameters(FScanner &sc, PClassActor *cls, TArray<FxExpression
 	int pnum = 0;
 	bool zeroparm;
 
-	if (afd->Variants[0].Flags & VARF_Method)
+	if (afd->Variants[0].Flags & VARF_Action)
+	{
+		numparams -= NAP;
+		pnum += NAP;
+	}
+	else if (afd->Variants[0].Flags & VARF_Method)
 	{
 		numparams--;
 		pnum++;
 	}
-	if (afd->Variants[0].Flags & VARF_Action)
-	{
-		numparams -= 2;
-		pnum += 2;
-	}
 	assert(numparams >= 0);
 	zeroparm = numparams == 0;
 	if (numparams > 0 && !(paramflags[pnum] & VARF_Optional))
diff --git a/src/scripting/thingdef.cpp b/src/scripting/thingdef.cpp
index 45e77b3ad9..2798ab633a 100644
--- a/src/scripting/thingdef.cpp
+++ b/src/scripting/thingdef.cpp
@@ -143,7 +143,7 @@ PFunction *CreateAnonymousFunction(PClass *containingclass, PType *returntype, i
 	SetImplicitArgs(&args, &argflags, &argnames, containingclass, flags);
 
 	PFunction *sym = new PFunction(containingclass, NAME_None);	// anonymous functions do not have names.
-	sym->AddVariant(NewPrototype(rets, args), argflags, argnames, nullptr, VARF_Action|VARF_Method);
+	sym->AddVariant(NewPrototype(rets, args), argflags, argnames, nullptr, flags);
 	return sym;
 }
 
diff --git a/src/scripting/zscript/zcc_compile.cpp b/src/scripting/zscript/zcc_compile.cpp
index 9b4212820e..e702f7d2a4 100644
--- a/src/scripting/zscript/zcc_compile.cpp
+++ b/src/scripting/zscript/zcc_compile.cpp
@@ -32,7 +32,7 @@
 **
 */
 
-#include "actor.h"
+#include "a_pickups.h"
 #include "thingdef.h"
 #include "sc_man.h"
 #include "c_console.h"