From 69ecab39f264ce1a5faa69f5648b38b3e94e0641 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Tue, 24 Feb 2026 17:10:01 -0500
Subject: [PATCH] Allow comparing rcp<T> to rcp<U>

---
 include/rcp.h  | 10 ++++++----
 test/tests.cpp | 12 ++++++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/rcp.h b/include/rcp.h
index 8e8f595..fbcd38c 100644
--- a/include/rcp.h
+++ b/include/rcp.h
@@ -147,14 +147,16 @@ public:
         return ptr != nullptr;
     }
 
-    bool operator==(const rcp & other) const
+    template <typename U>
+    bool operator==(const rcp<U> & other) const
     {
-        return ptr == other.ptr;
+        return static_cast<const void *>(ptr) == static_cast<const void *>(other.ptr);
     }
 
-    bool operator!=(const rcp & other) const
+    template <typename U>
+    bool operator!=(const rcp<U> & other) const
     {
-        return ptr != other.ptr;
+        return static_cast<const void *>(ptr) != static_cast<const void *>(other.ptr);
     }
 
     bool operator==(std::nullptr_t) const
diff --git a/test/tests.cpp b/test/tests.cpp
index 2e34fde..d4dac69 100644
--- a/test/tests.cpp
+++ b/test/tests.cpp
@@ -181,6 +181,17 @@ void test_move_assignment_releases_existing()
     assert(mybase_destruct == destructed_before + 2);
 }
 
+void test_cross_type_comparison()
+{
+    rcp<MyDerived> derived = MyDerived::create(1.5);
+    rcp<MyBase> base = derived;
+    assert(base == derived);
+    assert(!(base != derived));
+    rcp<MyBase> other = MyBase::create(1, 2);
+    assert(base != other);
+    assert(!(base == other));
+}
+
 void test_reset()
 {
     int destructed_before = mybase_destruct;
@@ -238,6 +249,7 @@ int main(int argc, char * argv[])
     test_create();
     test_multi_construct_from_raw_pointers();
     test_copy_assignment_decrements_previous_reference();
+    test_cross_type_comparison();
     test_reset();
     test_move_constructor();
     test_move_assignment();