Allow creating unhidden traps in special levels

des.trap({ type = "rust", seen = true });

src/mklev.c

@@ -1468,6 +1468,8 @@ mktrap(int num, int mktrapflags, struct mkroom *croom, coord *tm)
 
     if (kind == WEB && !(mktrapflags & MKTRAP_NOSPIDERONWEB))
         (void) makemon(&mons[PM_GIANT_SPIDER], m.x, m.y, NO_MM_FLAGS);
+    if ((mktrapflags & MKTRAP_SEEN))
+        t->tseen = TRUE;
 
     /* The hero isn't the only person who's entered the dungeon in
        search of treasure. On the very shallowest levels, there's a

src/sp_lev.c

@@ -1743,6 +1743,8 @@ create_trap(spltrap* t, struct mkroom* croom)
 
     if (!t->spider_on_web)
         mktrap_flags |= MKTRAP_NOSPIDERONWEB;
+    if (t->seen)
+        mktrap_flags |= MKTRAP_SEEN;
 
     tm.x = x;
     tm.y = y;
@@ -4117,6 +4119,7 @@ lspo_trap(lua_State *L)
         get_table_xy_or_coord(L, &x, &y);
         tmptrap.type = get_table_traptype_opt(L, "type", -1);
         tmptrap.spider_on_web = get_table_boolean_opt(L, "spider_on_web", 1);
+        tmptrap.seen = get_table_boolean_opt(L, "seen", FALSE);
     }
 
     if (tmptrap.type == NO_TRAP)