From 616f071cd93b2e6061878a7a581787a861cb2429 Mon Sep 17 00:00:00 2001
From: Skgland <bennet.blessmann+github@googlemail.com>
Date: Mon, 8 Dec 2025 19:59:43 +0100
Subject: [PATCH] fix another integer overflow

---
 src/machine/heap.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/machine/heap.rs b/src/machine/heap.rs
index c93d005b..d8c52ac8 100644
--- a/src/machine/heap.rs
+++ b/src/machine/heap.rs
@@ -1148,7 +1148,9 @@ pub fn sized_iter_to_heap_list<SrcT: Into<HeapCellValue>>(
 ) -> Result<HeapCellValue, AllocError> {
     if size > 0 {
         let h = heap.cell_len();
-        let mut writer = heap.reserve(1 + 2 * size)?;
+        // not using checked_add for 1 + as the result of multiplying by 2 will be even and the largest representable usize is odd,
+        // so the addition cannot overflow
+        let mut writer = heap.reserve(1 + size.checked_mul(2).ok_or(AllocError)?)?;
 
         writer.write_with(|section| {
             for (idx, value) in values.enumerate() {
-- 
2.54.0