diff --git a/src/corelib/tools/qvarlengtharray.h b/src/corelib/tools/qvarlengtharray.h
index 6ecc22213f4..67d8463a515 100644
--- a/src/corelib/tools/qvarlengtharray.h
+++ b/src/corelib/tools/qvarlengtharray.h
@@ -619,6 +619,8 @@ template <typename...Args>
 Q_OUTOFLINE_TEMPLATE auto QVarLengthArray<T, Prealloc>::emplace(const_iterator before, Args &&...args) -> iterator
 {
     Q_ASSERT_X(isValidIterator(before), "QVarLengthArray::insert", "The specified const_iterator argument 'before' is invalid");
+    Q_ASSERT(s <= a);
+    Q_ASSERT(a > 0);
 
     qsizetype offset = qsizetype(before - ptr);
     if (s == a)