Fire sources can ignite candles, lamps, and potions of oil

... on the floor, in monster inventory, and in hero's inventory.

Items in your inventory being ignited produce a message even if you're
blind - you can see the lit-state by viewing inventory anyway, so just
give player the message.

(via xNetHack)

src/mcastu.c

@@ -553,6 +553,7 @@ int spellnum;
         destroy_item(SCROLL_CLASS, AD_FIRE);
         destroy_item(POTION_CLASS, AD_FIRE);
         destroy_item(SPBOOK_CLASS, AD_FIRE);
+        ignite_items(g.invent);
         (void) burn_floor_objects(u.ux, u.uy, TRUE, FALSE);
         break;
     case CLC_LIGHTNING: {