Inaccessible niches occasionally have iron bars

doc/fixes35.0

@@ -900,6 +900,7 @@ mithril armor should have silver color
 lichen corpse is an acid indicator
 camera may contain a picture-painting demon
 some monsters can eat through iron bars
+inaccessible niches occasionally have iron bars in front
 
 
 Platform- and/or Interface-Specific Fixes

src/mklev.c

@@ -493,6 +493,15 @@ int trap_type;
 		if(rn2(7))
 		    dosdoor(xx, yy, aroom, rn2(5) ? SDOOR : DOOR);
 		else {
+		    /* inaccessible niches occasionally have iron bars */
+                    if (!rn2(5) && IS_WALL(levl[xx][yy].typ)) {
+                        levl[xx][yy].typ = IRONBARS;
+                        if (rn2(3))
+                            (void) mkcorpstat(CORPSE,
+                                              (struct monst *)0,
+                                              mkclass(S_HUMAN, 0),
+                                              xx, yy+dy, TRUE);
+                    }
 		    if (!level.flags.noteleport)
 			(void) mksobj_at(SCR_TELEPORTATION,
 					 xx, yy+dy, TRUE, FALSE);