Fix fuzzer teleporting out of Fort Ludios

src/do.c

@@ -1635,7 +1635,9 @@ goto_level(
                 /* returning from tutorial via portal */
                 u_on_newpos(stway->sx, stway->sy);
             } else {
-                panic("goto_level: no corresponding portal!");
+                if (!iflags.debug_fuzzer)
+                    impossible("goto_level: no corresponding portal!");
+                u_on_rndspot(0);
             }
         } else {
             seetrap(ttrap);

src/dog.c

@@ -490,6 +490,9 @@ mon_arrive(struct monst *mtmp, int when)
         if (t) {
             xlocale = t->tx, ylocale = t->ty;
             break;
+        } else if (iflags.debug_fuzzer && (stway = stairway_find_dir(TRUE)) != 0) {
+            /* debugfuzzer returning from knox */
+            xlocale = stway->sx, ylocale = stway->sy;
         } else if (!(u.uevent.qexpelled
                      && (Is_qstart(&u.uz0) || Is_qstart(&u.uz)))) {
             impossible("mon_arrive: no corresponding portal?");

src/mklev.c

@@ -1313,7 +1313,10 @@ place_branch(
     }
 
     if (br->type == BR_PORTAL) {
-        mkportal(x, y, dest->dnum, dest->dlevel);
+        if (u.ucamefrom.dnum || u.ucamefrom.dlevel)
+            mkportal(x, y, u.ucamefrom.dnum, u.ucamefrom.dlevel);
+        else
+            mkportal(x, y, dest->dnum, dest->dlevel);
     } else if (make_stairs) {
         boolean goes_up = on_level(&br->end1, &u.uz) ? br->end1_up
                                                      : !br->end1_up;

src/teleport.c

@@ -866,6 +866,7 @@ level_tele(void)
                  || gd.dungeons[newlevel.dnum].flags.unconnected
                  || !gd.dungeons[newlevel.dnum].num_dunlevs);
         newlevel.dlevel = 1 + rn2(dunlevs_in_dungeon(&newlevel));
+        assign_level(&u.ucamefrom, &u.uz);
         schedule_goto(&newlevel, UTOTYPE_NONE, (char *) 0, (char *) 0);
         return;
     }