Also require a rune to go from D:15 to D:14.

In case you somehow ended up there (for example early portal to Hell).

1 files changed, 19 insertions, 0 deletions

diff --git a/crawl-ref/source/stairs.cc b/crawl-ref/source/stairs.cc
index 8032a8e3ab..db17108349 100644
--- a/crawl-ref/source/stairs.cc
+++ b/crawl-ref/source/stairs.cc
@@ -352,6 +352,25 @@ void up_stairs(dungeon_feature_type force_stair)
             return down_stairs(force_stair);
     }
 
+    if (player_in_branch(BRANCH_MAIN_DUNGEON)
+        && you.depth == RUNE_LOCK_DEPTH + 1
+        && (feat_is_stone_stair(stair_find) || feat_is_escape_hatch(stair_find)))
+    {
+        bool has_rune = false;
+        for (int i = 0; i < NUM_RUNE_TYPES; i++)
+            if (you.runes[i])
+            {
+                has_rune = true;
+                break;
+            }
+
+        if (!has_rune)
+        {
+            mpr("You need a rune to go back up.");
+            return;
+        }
+    }
+
     // Only check the current position for a legal stair traverse.
     if (!force_stair && !_check_stairs(stair_find))
         return;