From ed73046c13401b42038a22bd1436a4de549181b4 Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@koefferlein.de>
Date: Sat, 16 Jan 2021 18:08:23 +0100
Subject: [PATCH] Allow flatten for non-editable layouts too

---
 src/db/db/dbLayout.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/db/db/dbLayout.cc b/src/db/db/dbLayout.cc
index b9b50047a..f08b0e6ce 100644
--- a/src/db/db/dbLayout.cc
+++ b/src/db/db/dbLayout.cc
@@ -984,7 +984,7 @@ Layout::flatten (const db::Cell &source_cell, db::Cell &target_cell, const db::I
       //  even an iteration of the instances requires an update.
       start_changes ();
 
-      db::Instances old_instances (0);
+      db::Instances old_instances (&target_cell);
       old_instances = target_cell.instances ();
       target_cell.clear_insts ();