From 320f7362b0cecfc39da41c418f1751a909ff49e9 Mon Sep 17 00:00:00 2001
From: Steven WdV <swdv@cs.ru.nl>
Date: Tue, 5 Nov 2024 10:32:36 +0100
Subject: [PATCH] Fix C++23 compatibility

---
 Rx/v2/src/rxcpp/operators/rx-concat_map.hpp   |   4 -
 Rx/v2/src/rxcpp/operators/rx-reduce.hpp       |   5 -
 Rx/v2/src/rxcpp/operators/rx-subscribe_on.hpp |   6 -
 Rx/v2/src/rxcpp/rx-includes.hpp               |   1 +
 Rx/v2/src/rxcpp/rx-util.hpp                   | 109 ++++++------------
 5 files changed, 34 insertions(+), 91 deletions(-)

diff --git a/Rx/v2/src/rxcpp/operators/rx-concat_map.hpp b/Rx/v2/src/rxcpp/operators/rx-concat_map.hpp
index ba91e6619..bfce4ab6d 100644
--- a/Rx/v2/src/rxcpp/operators/rx-concat_map.hpp
+++ b/Rx/v2/src/rxcpp/operators/rx-concat_map.hpp
@@ -115,8 +115,6 @@ struct concat_map
         collection_selector_type selectCollection;
         result_selector_type selectResult;
         coordination_type coordination;
-    private:
-        values& operator=(const values&) RXCPP_DELETE;
     };
     values initial;
 
@@ -275,8 +273,6 @@ struct concat_map
         source->subscribe(std::move(selectedSink.get()));
 
     }
-private:
-    concat_map& operator=(const concat_map&) RXCPP_DELETE;
 };
 
 }
diff --git a/Rx/v2/src/rxcpp/operators/rx-reduce.hpp b/Rx/v2/src/rxcpp/operators/rx-reduce.hpp
index 724d4f7ae..285a9668a 100644
--- a/Rx/v2/src/rxcpp/operators/rx-reduce.hpp
+++ b/Rx/v2/src/rxcpp/operators/rx-reduce.hpp
@@ -124,9 +124,6 @@ struct reduce : public operator_base<rxu::value_type_t<reduce_traits<T, Observab
         accumulator_type accumulator;
         result_selector_type result_selector;
         seed_type seed;
-
-    private:
-        reduce_initial_type& operator=(reduce_initial_type o) RXCPP_DELETE;
     };
     reduce_initial_type initial;
 
@@ -181,8 +178,6 @@ struct reduce : public operator_base<rxu::value_type_t<reduce_traits<T, Observab
             }
         );
     }
-private:
-    reduce& operator=(reduce o) RXCPP_DELETE;
 };
 
 template<class T>
diff --git a/Rx/v2/src/rxcpp/operators/rx-subscribe_on.hpp b/Rx/v2/src/rxcpp/operators/rx-subscribe_on.hpp
index 1a4d854e7..31ff4b914 100644
--- a/Rx/v2/src/rxcpp/operators/rx-subscribe_on.hpp
+++ b/Rx/v2/src/rxcpp/operators/rx-subscribe_on.hpp
@@ -59,8 +59,6 @@ struct subscribe_on : public operator_base<T>
         }
         source_type source;
         coordination_type coordination;
-    private:
-        subscribe_on_values& operator=(subscribe_on_values o) RXCPP_DELETE;
     };
     const subscribe_on_values initial;
 
@@ -87,8 +85,6 @@ struct subscribe_on : public operator_base<T>
             }
             composite_subscription source_lifetime;
             output_type out;
-        private:
-            subscribe_on_state_type& operator=(subscribe_on_state_type o) RXCPP_DELETE;
         };
 
         composite_subscription coordinator_lifetime;
@@ -138,8 +134,6 @@ struct subscribe_on : public operator_base<T>
 
         controller.schedule(selectedProducer.get());
     }
-private:
-    subscribe_on& operator=(subscribe_on o) RXCPP_DELETE;
 };
 
 }
diff --git a/Rx/v2/src/rxcpp/rx-includes.hpp b/Rx/v2/src/rxcpp/rx-includes.hpp
index 55b1e0be1..3e53fbcc7 100644
--- a/Rx/v2/src/rxcpp/rx-includes.hpp
+++ b/Rx/v2/src/rxcpp/rx-includes.hpp
@@ -181,6 +181,7 @@
 #include <map>
 #include <set>
 #include <mutex>
+#include <optional>
 #include <deque>
 #include <thread>
 #include <future>
diff --git a/Rx/v2/src/rxcpp/rx-util.hpp b/Rx/v2/src/rxcpp/rx-util.hpp
index cf641812e..11c490e3a 100644
--- a/Rx/v2/src/rxcpp/rx-util.hpp
+++ b/Rx/v2/src/rxcpp/rx-util.hpp
@@ -490,8 +490,6 @@ struct endline
     void operator()() const {
         os << std::endl;
     }
-private:
-    endline& operator=(const endline&) RXCPP_DELETE;
 };
 
 template<class OStream, class ValueType>
@@ -503,8 +501,6 @@ struct insert_value
     void operator()() const {
         os << value;
     }
-private:
-    insert_value& operator=(const insert_value&) RXCPP_DELETE;
 };
 
 template<class OStream, class Function>
@@ -516,8 +512,6 @@ struct insert_function
     void operator()() const {
         call(os);
     }
-private:
-    insert_function& operator=(const insert_function&) RXCPP_DELETE;
 };
 
 template<class OStream, class Delimit>
@@ -568,131 +562,94 @@ namespace detail {
 template <class T>
 class maybe
 {
-    bool is_set;
-    typename std::aligned_storage<sizeof(T), std::alignment_of<T>::value>::type
-        storage;
+    std::optional<T> val_;
 public:
-    maybe()
-    : is_set(false)
-    {
-    }
+    maybe() = default;
 
     maybe(const T& value)
-    : is_set(false)
+    : val_(value)
     {
-        new (reinterpret_cast<T*>(&storage)) T(value);
-        is_set = true;
     }
 
     maybe(T&& value)
-    : is_set(false)
-    {
-        new (reinterpret_cast<T*>(&storage)) T(std::move(value));
-        is_set = true;
-    }
-
-    maybe(const maybe& other)
-    : is_set(false)
-    {
-        if (other.is_set) {
-            new (reinterpret_cast<T*>(&storage)) T(other.get());
-            is_set = true;
-        }
-    }
-    maybe(maybe&& other)
-    : is_set(false)
+    : val_(std::move(value))
     {
-        if (other.is_set) {
-            new (reinterpret_cast<T*>(&storage)) T(std::move(other.get()));
-            is_set = true;
-            other.reset();
-        }
     }
 
-    ~maybe()
-    {
-        reset();
-    }
+    maybe(const maybe& other) = default;
+    maybe(maybe&& other) = default;
 
     using value_type = T;
     using iterator = T *;
     using const_iterator = const T *;
 
     bool empty() const {
-        return !is_set;
+        return !val_;
     }
 
     std::size_t size() const {
-        return is_set ? 1 : 0;
+        return val_ ? 1 : 0;
     }
 
     iterator begin() {
-        return reinterpret_cast<T*>(&storage);
+        return val_ ? &*val_ : nullptr;
     }
     const_iterator begin() const {
-        return reinterpret_cast<T*>(&storage);
+        return val_ ? &*val_ : nullptr;
     }
 
     iterator end() {
-        return reinterpret_cast<T*>(&storage) + size();
+        return begin() + size();
     }
     const_iterator end() const {
-        return reinterpret_cast<T*>(&storage) + size();
+        return begin() + size();
     }
 
     T* operator->() {
-        if (!is_set) std::terminate();
-        return reinterpret_cast<T*>(&storage);
+        if (!val_) std::terminate();
+        return val_.operator->();
     }
     const T* operator->() const {
-        if (!is_set) std::terminate();
-        return reinterpret_cast<T*>(&storage);
+        if (!val_) std::terminate();
+        return val_.operator->();
     }
 
     T& operator*() {
-        if (!is_set) std::terminate();
-        return *reinterpret_cast<T*>(&storage);
+        if (!val_) std::terminate();
+        return *val_;
     }
     const T& operator*() const {
-        if (!is_set) std::terminate();
-        return *reinterpret_cast<T*>(&storage);
+        if (!val_) std::terminate();
+        return *val_;
     }
 
     T& get() {
-        if (!is_set) std::terminate();
-        return *reinterpret_cast<T*>(&storage);
+        return **this;
     }
     const T& get() const {
-        if (!is_set) std::terminate();
-        return *reinterpret_cast<const T*>(&storage);
+        return **this;
     }
 
     void reset()
     {
-        if (is_set) {
-            is_set = false;
-            reinterpret_cast<T*>(&storage)->~T();
-            //std::fill_n(reinterpret_cast<char*>(&storage), sizeof(T), 0);
-        }
+        val_.reset();
     }
 
-    template<class U>
+    template<class U = T>
     void reset(U&& value) {
-        reset();
-        new (reinterpret_cast<T*>(&storage)) T(std::forward<U>(value));
-        is_set = true;
+        *this = std::forward<U>(value);
     }
 
-    maybe& operator=(const T& other) {
-        reset(other);
+    maybe& operator=(const maybe& other) = default;
+    maybe& operator=(maybe&& other) = default;
+
+    maybe& operator=(const T& value) {
+        val_ = value;
         return *this;
     }
-    maybe& operator=(const maybe& other) {
-        if (!other.empty()) {
-            reset(other.get());
-        } else {
-            reset();
-        }
+
+    maybe& operator=(T&& value) {
+        val_ = std::move(value);
         return *this;
     }
 };