From 07defbe5402fdbf119b70ee83ea420b6b7380131 Mon Sep 17 00:00:00 2001
From: Richard Brooksby <rb@ravenbrook.com>
Date: Thu, 9 Mar 2023 22:35:14 +0000
Subject: [PATCH] Clarifying purpose of local variables in response to review
 <https://github.com/Ravenbrook/mps/pull/34/files#r1123294923>.

---
 code/walk.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/code/walk.c b/code/walk.c
index 0b3d96baf9..088ede3ea0 100644
--- a/code/walk.c
+++ b/code/walk.c
@@ -453,8 +453,9 @@ static Res poolWalk(Arena arena, Pool pool, mps_area_scan_t area_scan, void *clo
   ss.fix = walkNoFix;
 
   RING_FOR(node, &pool->segRing, nextNode) {
-    Bool wasTotal;
+    Bool wasTotal; /* did we scan every object in the seg? */
     Seg seg = SegOfPoolRing(node);
+    /* Only segments that contain references need a summary. */
     Bool needSummary = SegRankSet(seg) != RankSetEMPTY;
 
     if (needSummary)