From b44ff4b8e8f679ecc946947f4157b8b295a21c14 Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@klayout.de>
Date: Sun, 6 Oct 2024 19:07:17 +0200
Subject: [PATCH] Avoid a potential hard assertion in debug mode

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

diff --git a/src/lay/lay/layMacroEditorPage.cc b/src/lay/lay/layMacroEditorPage.cc
index b0818e6f4..5b601b6e9 100644
--- a/src/lay/lay/layMacroEditorPage.cc
+++ b/src/lay/lay/layMacroEditorPage.cc
@@ -753,7 +753,7 @@ void MacroEditorPage::fill_completer_list ()
   QString ssel = c.selectedText ();
   QString s = ssel.mid (0, pos - pos0);
 
-  if (! s[0].isLetter () && s[0].toLatin1 () != '_') {
+  if (s.length () == 0 || (! s[0].isLetter () && s[0].toLatin1 () != '_')) {
     return;  // not a word
   }