From 6aabc74a535da1f2d5cf866346b31939d097cbac Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Tue, 16 Jul 2024 12:23:50 +0200
Subject: w

---
 compat/borrowed-ptr.hpp | 24 +++++++++++++-----------
 compat/borrowed-ptr.inl | 10 +++++++---
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/compat/borrowed-ptr.hpp b/compat/borrowed-ptr.hpp
index 62394087..7ab42ebb 100644
--- a/compat/borrowed-ptr.hpp
+++ b/compat/borrowed-ptr.hpp
@@ -24,25 +24,24 @@ struct control_block final
     static void weak_decrement(control_block*& blk) noexcept;
 };
 
+#if 0
 template<typename From, typename To>
-concept StaticCastable = requires(From* from) {
+concept StaticCastable = requires(From* from, To* to) {
     static_cast<To*>(from);
-    requires std::is_base_of_v<std::remove_cvref_t<From>, std::remove_cvref_t<To>>;
+    static_cast<const bptr_base*>(from);
+    static_cast<const bptr_base*>(to);
 };
 
 template<typename From, typename To>
-concept DerivedFrom = requires(From* x) {
-#if 0
+concept DerivedFrom = requires(From* from, To* to) {
+    static_cast<const bptr_base*>(from);
+    static_cast<const bptr_base*>(to);
     requires std::is_convertible_v<From*, To*>;
-    requires std::is_convertible_v<From*, const bptr_base*>;
-    requires std::is_convertible_v<To*, const bptr_base*>;
-    requires std::is_base_of_v<bptr_base, From>;
-    requires std::is_base_of_v<bptr_base, To>;
-    requires std::is_base_of_v<std::remove_cvref_t<To>, std::remove_cvref_t<From>>;
+};
 #else
-    static_cast<To*>(std::declval<From*>());
+template<typename From, typename To> concept DerivedFrom = true;
+template<typename From, typename To> concept StaticCastable = true;
 #endif
-};
 
 } // namespace floormat::detail_bptr
 
@@ -103,6 +102,9 @@ public:
     explicit operator bool() const noexcept;
 
     bool operator==(const bptr<const T>& other) const noexcept;
+    bool operator==(const bptr<T>& other) const noexcept requires (!std::is_const_v<T>);
+    bool operator==(const std::nullptr_t& other) const noexcept;
+
     std::strong_ordering operator<=>(const bptr<const T>& other) const noexcept;
 
     template<typename U> friend class bptr;
diff --git a/compat/borrowed-ptr.inl b/compat/borrowed-ptr.inl
index 2ffd1e92..327bd7cd 100644
--- a/compat/borrowed-ptr.inl
+++ b/compat/borrowed-ptr.inl
@@ -145,12 +145,16 @@ template<typename T> T& bptr<T>::operator*() const noexcept { return *operator->
 
 template<typename T> bptr<T>::operator bool() const noexcept { return blk && blk->_ptr; }
 
-template<typename T>
-bool bptr<T>::operator==(const bptr<const T>& other) const noexcept
+template<typename T> bool bptr<T>::operator==(const bptr<const T>& other) const noexcept
 {
-    return !blk == !other.blk && blk->_ptr == other.blk->_ptr;
+    return blk ? (other.blk && blk->_ptr == other.blk->_ptr) : !other.blk;
+}
+template<typename T> bool bptr<T>::operator==(const bptr<T>& other) const noexcept requires (!std::is_const_v<T>) {
+    return blk ? (other.blk && blk->_ptr == other.blk->_ptr) : !other.blk;
 }
 
+template<typename T> bool bptr<T>::operator==(const std::nullptr_t&) const noexcept { return !blk || !blk->_ptr; }
+
 template<typename T>
 std::strong_ordering bptr<T>::operator<=>(const bptr<const T>& other) const noexcept
 {
-- 
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