From bb2c1c3485b0da4f2463c18caecc42975e8d8dfb Mon Sep 17 00:00:00 2001
From: Enrico Forestieri <forenr@lyx.org>
Date: Mon, 1 Mar 2021 10:08:08 +0100
Subject: [PATCH] Amend c2facb8c

Make sure the base of a script is not empty before accessing it.
---
 src/Cursor.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Cursor.cpp b/src/Cursor.cpp
index 6412c0e2f7..ad46e8c505 100644
--- a/src/Cursor.cpp
+++ b/src/Cursor.cpp
@@ -2041,7 +2041,7 @@ bool Cursor::mathForward(bool word)
 				while (pos() < lastpos() && mc == nextMath().mathClass());
 		} else if (openable(nextAtom())) {
 			InsetMathScript const * n = nextMath().asScriptInset();
-			bool to_brace_deco = n
+			bool to_brace_deco = n && !n->nuc().empty()
 				&& n->nuc().back()->lyxCode() == MATH_DECORATION_CODE
 				&& n->nuc().back()->mathClass() == MC_OP;
 			// single step: try to enter the next inset
@@ -2095,7 +2095,7 @@ bool Cursor::mathBackward(bool word)
 			}
 		} else if (openable(prevAtom())) {
 			InsetMathScript const * p = prevMath().asScriptInset();
-			bool to_brace_deco = p
+			bool to_brace_deco = p && !p->nuc().empty()
 				&& p->nuc().back()->lyxCode() == MATH_DECORATION_CODE
 				&& p->nuc().back()->mathClass() == MC_OP;
 			// single step: try to enter the preceding inset
-- 
2.39.5