fix: Add consteval-friendly path

Author: FrozenLemonTee

src/primitive/impl.cppm

@@ -43,8 +43,7 @@ struct resolve_concurrency_policy<First, Rest...> {
 };
 
 template <policy::policy_type... Policies>
-using resolve_concurrency_policy_t =
-    typename resolve_concurrency_policy<Policies...>::type;
+using resolve_concurrency_policy_t = resolve_concurrency_policy<Policies...>::type;
 
 } // namespace details
 
@@ -58,44 +57,85 @@ public:
                 "Multiple concurrency policies are not allowed");
 
   constexpr explicit primitive(value_type v) noexcept : value_(v) {}
-  primitive(primitive const &other) noexcept : value_(other.load()) {}
-  auto operator=(primitive const &other) noexcept -> primitive & {
+
+  constexpr primitive(primitive const &other) noexcept {
+    if consteval {
+      value_ = other.value_;
+    } else {
+      value_ = other.load();
+    }
+  }
+
+  constexpr auto operator=(primitive const &other) noexcept -> primitive & {
     if (this == &other) {
       return *this;
     }
 
-    store(other.load());
+    if consteval {
+      value_ = other.value_;
+    } else {
+      store(other.load());
+    }
     return *this;
   }
 
-  primitive(primitive &&other) noexcept : value_(other.load()) {}
-  auto operator=(primitive &&other) noexcept -> primitive & {
+  constexpr primitive(primitive &&other) noexcept {
+    if consteval {
+      value_ = other.value_;
+    } else {
+      value_ = other.load();
+    }
+  }
+
+  constexpr auto operator=(primitive &&other) noexcept -> primitive & {
     if (this == &other) {
       return *this;
     }
 
-    store(other.load());
+    if consteval {
+      value_ = other.value_;
+    } else {
+      store(other.load());
+    }
     return *this;
   }
 
   constexpr value_type &value() noexcept { return value_; }
+
   [[nodiscard]] constexpr value_type const &value() const noexcept {
     return value_;
   }
+
   constexpr explicit operator value_type() const noexcept { return value_; }
 
-  [[nodiscard]] auto load() const noexcept -> value_type {
+  [[nodiscard]] constexpr auto load() const noexcept -> value_type {
+    if consteval {
+      return value_;
+    }
     require_access_handler_();
     return access_handler_t::load(value_);
   }
 
-  auto store(value_type desired) noexcept -> void {
-    require_access_handler_();
-    access_handler_t::store(value_, desired);
+  constexpr auto store(value_type desired) noexcept -> void {
+    if consteval {
+      value_ = desired;
+    } else {
+      require_access_handler_();
+      access_handler_t::store(value_, desired);
+    }
   }
 
-  auto compare_exchange(value_type &expected, value_type desired) noexcept
-      -> bool {
+  constexpr auto compare_exchange(value_type &expected,
+                                  value_type desired) noexcept -> bool {
+    if consteval {
+      if (value_ != expected) {
+        expected = value_;
+        return false;
+      }
+
+      value_ = desired;
+      return true;
+    }
     require_access_handler_();
     return access_handler_t::compare_exchange(value_, expected, desired);
   }