From c95f803a5bb2d8447c8021b3157bc2706bc3ecdf Mon Sep 17 00:00:00 2001
From: Emil Dotchevski <emildotchevski@gmail.com>
Date: Tue, 12 Dec 2023 10:33:37 -0800
Subject: [PATCH] Minor tweaks to leaf_detail::capture_list

---
 include/boost/leaf/detail/capture_list.hpp | 28 +++++++++-------------
 include/boost/leaf/error.hpp               | 11 +++++----
 2 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/include/boost/leaf/detail/capture_list.hpp b/include/boost/leaf/detail/capture_list.hpp
index 4d0e2992..491415a8 100644
--- a/include/boost/leaf/detail/capture_list.hpp
+++ b/include/boost/leaf/detail/capture_list.hpp
@@ -49,8 +49,7 @@ namespace leaf_detail
                 *last = this;
                 last = &next_;
             }
-        };
-        node * first_;
+        } * first_;
 
         template <class F>
         BOOST_LEAF_CONSTEXPR void for_each( F f ) const
@@ -59,17 +58,6 @@ namespace leaf_detail
                 f(*p);
         }
 
-        void clear() noexcept
-        {
-            for( node const * p = first_; p; )
-            {
-                node const * n = p -> next_;
-                delete p;
-                p = n;
-            }
-            first_ = nullptr;
-        }
-
     public:
 
         BOOST_LEAF_CONSTEXPR explicit capture_list( node * first ) noexcept:
@@ -85,18 +73,24 @@ namespace leaf_detail
 
         ~capture_list() noexcept
         {
-            clear();
+            for( node const * p = first_; p; )
+            {
+                node const * n = p -> next_;
+                delete p;
+                p = n;
+            }
         }
 
         void unload( int const err_id )
         {
+            capture_list moved(first_);
+            first_ = nullptr;
             tls::write_uint<leaf_detail::tls_tag_id_factory_current_id>(unsigned(err_id));
-            for_each(
+            moved.for_each(
                 [err_id]( node & n )
                 {
-                    n.unload(err_id);
+                    n.unload(err_id); // last node may throw
                 } );
-            clear();
         }
 
         template <class CharT, class Traits>
diff --git a/include/boost/leaf/error.hpp b/include/boost/leaf/error.hpp
index dd890e82..b77b68c1 100644
--- a/include/boost/leaf/error.hpp
+++ b/include/boost/leaf/error.hpp
@@ -337,7 +337,7 @@ namespace leaf_detail
             BOOST_LEAF_ASSERT(last_ != nullptr);
             BOOST_LEAF_ASSERT(*last_ == nullptr);
             BOOST_LEAF_ASSERT(other.first_ == nullptr);
-            other.last_ = nullptr;
+            other.last_ = &other.first_;
         }
 
         template <class E>
@@ -364,18 +364,19 @@ namespace leaf_detail
 
         bool empty() const noexcept
         {
-            return last_ == &first_;
+            BOOST_LEAF_ASSERT(first_ != nullptr || last_ == &first_);
+            return first_ != nullptr;
         }
 
         int size() const noexcept
         {
-            int n = 0;
+            int c = 0;
             for_each(
                 [&]( capture_list::node const & )
                 {
-                    ++n;
+                    ++c;
                 } );
-            return n;
+            return c;
         }
 
         template <class T>