From f568cc6d968aa77105bc2442705a6320613f185c Mon Sep 17 00:00:00 2001
From: 0penBrain <48731257+0penBrain@users.noreply.github.com>
Date: Mon, 29 Nov 2021 21:40:20 +0100
Subject: [PATCH] [Sketcher][Bugfix] Slot: fix segfault accessing empty vector

---
 src/Mod/Sketcher/Gui/CommandCreateGeo.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
index 26bb0f6ebe..ac64ff6663 100644
--- a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
+++ b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
@@ -7145,7 +7145,8 @@ public:
             try {
                 Gui::Command::openCommand(QT_TRANSLATE_NOOP("Command", "Add slot"));
 
-                AutoConstraint lastCons = sugConstr2.back();
+                AutoConstraint lastCons = {Sketcher::None, Sketcher::Constraint::GeoUndef, Sketcher::none};
+                if (!sugConstr2.empty()) lastCons = sugConstr2.back();
 
                 ostringstream snapCon = ostringstream("");
                 if (SnapMode == SNAP_MODE_Straight) {