From f655dbb86a2fac08bada154aed1902b8af2c926c Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Mon, 16 Feb 2026 00:48:00 -0500
Subject: [PATCH] xo-expression2 stack: expand MemorySizeInfo w/ per-type
 detail

---
 include/xo/reflectutil/typeseq.hpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/xo/reflectutil/typeseq.hpp b/include/xo/reflectutil/typeseq.hpp
index 336f011c..d337cd5b 100644
--- a/include/xo/reflectutil/typeseq.hpp
+++ b/include/xo/reflectutil/typeseq.hpp
@@ -61,7 +61,7 @@ namespace xo {
             }
 
         private:
-            int32_t seqno_ = 0;
+            int32_t seqno_ = -1;
             std::string_view name_;
         };
 
@@ -91,10 +91,11 @@ namespace xo {
                 return typeseq(xo::reflect::typerecd::recd<T>().seqno());
             }
 
+            bool is_sentinel() const { return seqno_ == -1; }
             int32_t seqno() const { return seqno_; }
 
         private:
-            int32_t seqno_ = 0;
+            int32_t seqno_ = -1;
         };
 
         //template <typename Tag>