- block off the Substitute function by making it private to the 3 classes that really need it.

src/scripting/vmthunks_actors.cpp

@@ -1614,6 +1614,22 @@ DEFINE_ACTION_FUNCTION_NATIVE(AActor, Substitute, StaticPointerSubstitution)
 	return 0;
 }
 
+DEFINE_ACTION_FUNCTION_NATIVE(_PlayerPawn, Substitute, StaticPointerSubstitution)
+{
+	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_OBJECT(replace, AActor);
+	StaticPointerSubstitution(self, replace);
+	return 0;
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(_MorphedMonster, Substitute, StaticPointerSubstitution)
+{
+	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_OBJECT(replace, AActor);
+	StaticPointerSubstitution(self, replace);
+	return 0;
+}
+
 DEFINE_ACTION_FUNCTION_NATIVE(AActor, GetSpawnableType, P_GetSpawnableType)
 {
 	PARAM_PROLOGUE;

wadsrc/static/zscript/actors/actor.zs

@@ -459,7 +459,7 @@ class Actor : Thinker native
 	virtual native void Die(Actor source, Actor inflictor, int dmgflags = 0, Name MeansOfDeath = 'none');
 	virtual native bool Slam(Actor victim);
 	virtual native void Touch(Actor toucher);
-	native void Substitute(Actor replacement);
+	private native void Substitute(Actor replacement);
 	native ui void DisplayNameTag();
 
 	// Called by inventory items to see if this actor is capable of touching them.

wadsrc/static/zscript/actors/player/player_morph.zs

@@ -1,5 +1,7 @@
 extend class PlayerPawn
 {
+	private native void Substitute(PlayerPawn replacement);
+
 	//===========================================================================
 	//
 	// EndAllPowerupEffects
@@ -503,6 +505,8 @@ class MorphedMonster : Actor
 		+FLOORCLIP
 	}
 
+	private native void Substitute(Actor replacement);
+
 	override void OnDestroy ()
 	{
 		if (UnmorphedMe != NULL)