Fix a --mapstat crash with > 8 octorings.

Data such as uniques or artefacts generated is cleared between generator runs,
and there is enough runs for oddities like this.

1 files changed, 4 insertions, 0 deletions

diff --git a/crawl-ref/source/dbg-maps.cc b/crawl-ref/source/dbg-maps.cc
index a7fc38bc71..ec72f16390 100644
--- a/crawl-ref/source/dbg-maps.cc
+++ b/crawl-ref/source/dbg-maps.cc
@@ -405,6 +405,10 @@ static void _write_mapgen_stats()
 
 void generate_map_stats()
 {
+    // Warn assertions about possible oddities like the artefact list being
+    // cleared.
+    you.wizard = true;
+
     initialise_branch_depths();
     // We have to run map preludes ourselves.
     run_map_global_preludes();