From f5f25ffcabcfe9dbc2640b55dc36776d74133678 Mon Sep 17 00:00:00 2001
From: Bas Schoenmaeckers <b.schoenmaeckers@zandersgroup.com>
Date: Mon, 11 May 2026 13:23:49 +0200
Subject: [PATCH 1/2] Add macro for type check function in c-api

---
 crates/capi/src/object.rs | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/crates/capi/src/object.rs b/crates/capi/src/object.rs
index 47ac58560db..c3ce0a5d023 100644
--- a/crates/capi/src/object.rs
+++ b/crates/capi/src/object.rs
@@ -7,6 +7,35 @@ use rustpython_vm::{AsObject, Py};
 
 pub type PyTypeObject = Py<PyType>;
 
+macro_rules! define_py_check {
+    ($name:ident, $($ctx_path:ident).+) => {
+        #[unsafe(no_mangle)]
+        pub unsafe extern "C" fn $name(obj: *mut crate::PyObject) -> core::ffi::c_int {
+            crate::pystate::with_vm(|vm| unsafe {
+                obj
+                .as_ref()
+                .map(|obj| obj.class().is_subtype(vm.ctx.$($ctx_path).+))
+                .unwrap_or_default()
+            })
+        }
+    };
+    (exact $name:ident, $($ctx_path:ident).+) => {
+        #[unsafe(no_mangle)]
+        pub unsafe extern "C" fn $name(obj: *mut crate::PyObject) -> core::ffi::c_int {
+            use rustpython_vm::AsObject;
+            crate::pystate::with_vm(|vm| unsafe {
+                obj
+                .as_ref()
+                .map(|obj| obj.class().is(vm.ctx.$($ctx_path).+))
+                .unwrap_or_default()
+            })
+        }
+    };
+}
+
+define_py_check!(PyType_Check, types.type_type);
+define_py_check!(exact PyType_CheckExact, types.type_type);
+
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn Py_TYPE(op: *mut PyObject) -> *const PyTypeObject {
     unsafe { (*op).class() }
@@ -27,6 +56,15 @@ pub unsafe extern "C" fn PyType_GetFlags(ptr: *const PyTypeObject) -> c_ulong {
     ty.slots.flags.bits() as u32 as c_ulong
 }
 
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyType_IsSubtype(a: *const PyTypeObject, b: *const PyTypeObject) -> c_int {
+    with_vm(move |_vm| {
+        let a = unsafe { &*a };
+        let b = unsafe { &*b };
+        Ok(a.is_subtype(b))
+    })
+}
+
 #[unsafe(no_mangle)]
 pub extern "C" fn Py_GetConstantBorrowed(constant_id: c_uint) -> *mut PyObject {
     with_vm(|vm| {

From cc1455b74c7ceb8cc7866f5dbf60592f6487689a Mon Sep 17 00:00:00 2001
From: Bas Schoenmaeckers <b.schoenmaeckers@zandersgroup.com>
Date: Sat, 16 May 2026 13:11:28 +0200
Subject: [PATCH 2/2] Add `fn` to macro

---
 crates/capi/src/object.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/crates/capi/src/object.rs b/crates/capi/src/object.rs
index c3ce0a5d023..f71475049f8 100644
--- a/crates/capi/src/object.rs
+++ b/crates/capi/src/object.rs
@@ -8,7 +8,7 @@ use rustpython_vm::{AsObject, Py};
 pub type PyTypeObject = Py<PyType>;
 
 macro_rules! define_py_check {
-    ($name:ident, $($ctx_path:ident).+) => {
+    (fn $name:ident, $($ctx_path:ident).+) => {
         #[unsafe(no_mangle)]
         pub unsafe extern "C" fn $name(obj: *mut crate::PyObject) -> core::ffi::c_int {
             crate::pystate::with_vm(|vm| unsafe {
@@ -19,7 +19,7 @@ macro_rules! define_py_check {
             })
         }
     };
-    (exact $name:ident, $($ctx_path:ident).+) => {
+    (exact fn $name:ident, $($ctx_path:ident).+) => {
         #[unsafe(no_mangle)]
         pub unsafe extern "C" fn $name(obj: *mut crate::PyObject) -> core::ffi::c_int {
             use rustpython_vm::AsObject;
@@ -33,8 +33,8 @@ macro_rules! define_py_check {
     };
 }
 
-define_py_check!(PyType_Check, types.type_type);
-define_py_check!(exact PyType_CheckExact, types.type_type);
+define_py_check!(fn PyType_Check, types.type_type);
+define_py_check!(exact fn PyType_CheckExact, types.type_type);
 
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn Py_TYPE(op: *mut PyObject) -> *const PyTypeObject {