- after realizing that changing the sector's MOD variable to an FNameNoInit doesn't do anything bad, I just went ahead and got rid of the last place in the engine that still used this data type for internal storage.

src/p_lnspec.cpp

@@ -2276,7 +2276,7 @@ FUNC(LS_Sector_SetDamage)
 			}
 		}
 		sectors[secnum].damageamount = (short)arg1;
-		sectors[secnum].damagemod = (short)arg2;
+		sectors[secnum].damagetype = MODtoDamageType(arg2);
 		sectors[secnum].damageinterval = (short)arg3;
 		sectors[secnum].leakydamage = (short)arg4;
 	}

src/p_saveg.cpp

@@ -369,15 +369,18 @@ void P_SerializeWorld (FArchive &arc)
 			<< sec->heightsec
 			<< sec->bottommap << sec->midmap << sec->topmap
 			<< sec->gravity
-			<< sec->damageamount
-			<< sec->damagemod;
+			<< sec->damageamount;
 		if (SaveVersion >= 4528)
 		{
 			arc << sec->damageinterval
-				<< sec->leakydamage;
+				<< sec->leakydamage
+				<< sec->damagetype;
 		}
 		else
 		{
+			short damagemod;
+			arc << damagemod;
+			sec->damagetype = MODtoDamageType(damagemod);
 			if (sec->damageamount < 20)
 			{
 				sec->leakydamage = 0;

src/p_spec.cpp

@@ -570,7 +570,7 @@ void P_PlayerInSpecialSector (player_t *player, sector_t * sector)
 	{
 		if (level.time % sector->damageinterval == 0 && (ironfeet == NULL || pr_playerinspecialsector() < sector->leakydamage))
 		{
-			P_DamageMobj (player->mo, NULL, NULL, sector->damageamount, MODtoDamageType (sector->damagemod));
+			P_DamageMobj (player->mo, NULL, NULL, sector->damageamount, sector->damagetype);
 		}
 	}
 
@@ -1439,7 +1439,7 @@ void P_SpawnSpecials (void)
 					{
 						sector_t *sec = &sectors[s];
 						sec->damageamount = damage;
-						sec->damagemod = 0;//MOD_UNKNOWN;
+						sec->damagetype = NAME_None;
 						if (sec->damageamount < 20)
 						{
 							sec->leakydamage = 0;

src/r_defs.h

@@ -710,8 +710,8 @@ struct sector_t
 	struct msecnode_t *touching_thinglist;				// phares 3/14/98
 
 	float gravity;			// [RH] Sector gravity (1.0 is normal)
+	FNameNoInit damagetype;		// [RH] Means-of-death for applied damage
 	short damageamount;			// [RH] Damage to do while standing on floor
-	short damagemod;		// [RH] Means-of-death for applied damage
 	short damageinterval;	// Interval for damage application
 	short leakydamage;		// chance of leaking through radiation suit