diff --git a/Cargo.toml b/Cargo.toml
index e54ac656..fe18ed7f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -52,7 +52,7 @@ serde_json = "1.0.61"
 pyo3-build-config = { path = "pyo3-build-config", version = "0.15.1", features = ["resolve-config"] }
 
 [features]
-default = ["macros"]
+default = ["macros", "pyproto"]
 
 # Enables macros: #[pyclass], #[pymodule], #[pyfunction] etc.
 macros = ["pyo3-macros", "indoc", "unindent"]
@@ -60,6 +60,9 @@ macros = ["pyo3-macros", "indoc", "unindent"]
 # Enables multiple #[pymethods] per #[pyclass]
 multiple-pymethods = ["inventory", "pyo3-macros/multiple-pymethods"]
 
+# Enables deprecated #[pyproto] macro
+pyproto = ["pyo3-macros/pyproto"]
+
 # Use this feature when building an extension module.
 # It tells the linker to keep the python symbols unresolved,
 # so that the module can also be used with statically linked python interpreters.
@@ -83,7 +86,7 @@ nightly = []
 
 # Activates all additional features
 # This is mostly intended for testing purposes - activating *all* of these isn't particularly useful.
-full = ["macros", "multiple-pymethods", "num-bigint", "num-complex", "hashbrown", "serde", "indexmap", "eyre", "anyhow"]
+full = ["macros", "pyproto", "multiple-pymethods", "num-bigint", "num-complex", "hashbrown", "serde", "indexmap", "eyre", "anyhow"]
 
 [[bench]]
 name = "bench_call"
diff --git a/Makefile b/Makefile
index d7a87d47..668807e3 100644
--- a/Makefile
+++ b/Makefile
@@ -3,9 +3,6 @@
 ALL_ADDITIVE_FEATURES = macros multiple-pymethods num-bigint num-complex hashbrown serde indexmap eyre anyhow
 COVERAGE_PACKAGES = --package pyo3 --package pyo3-build-config --package pyo3-macros-backend --package pyo3-macros
 
-list_all_additive_features:
-	@echo $(ALL_ADDITIVE_FEATURES)
-
 test: lint test_py
 	cargo test
 	cargo test --features="abi3"
diff --git a/guide/src/class.md b/guide/src/class.md
index 51c6e01d..8ad79a35 100644
--- a/guide/src/class.md
+++ b/guide/src/class.md
@@ -849,17 +849,17 @@ impl pyo3::IntoPy<PyObject> for MyClass {
     }
 }
 
-impl pyo3::class::impl_::PyClassImpl for MyClass {
+impl pyo3::impl_::pyclass::PyClassImpl for MyClass {
     const DOC: &'static str = "Class for demonstration\u{0}";
     const IS_GC: bool = false;
     const IS_BASETYPE: bool = false;
     const IS_SUBCLASS: bool = false;
     type Layout = PyCell<MyClass>;
     type BaseType = PyAny;
-    type ThreadChecker = pyo3::class::impl_::ThreadCheckerStub<MyClass>;
+    type ThreadChecker = pyo3::impl_::pyclass::ThreadCheckerStub<MyClass>;
 
     fn for_each_method_def(visitor: &mut dyn FnMut(&[pyo3::class::PyMethodDefType])) {
-        use pyo3::class::impl_::*;
+        use pyo3::impl_::pyclass::*;
         let collector = PyClassImplCollector::<MyClass>::new();
         visitor(collector.py_methods());
         visitor(collector.py_class_descriptors());
@@ -870,23 +870,23 @@ impl pyo3::class::impl_::PyClassImpl for MyClass {
         visitor(collector.number_protocol_methods());
     }
     fn get_new() -> Option<pyo3::ffi::newfunc> {
-        use pyo3::class::impl_::*;
+        use pyo3::impl_::pyclass::*;
         let collector = PyClassImplCollector::<Self>::new();
         collector.new_impl()
     }
     fn get_alloc() -> Option<pyo3::ffi::allocfunc> {
-        use pyo3::class::impl_::*;
+        use pyo3::impl_::pyclass::*;
         let collector = PyClassImplCollector::<Self>::new();
         collector.alloc_impl()
     }
     fn get_free() -> Option<pyo3::ffi::freefunc> {
-        use pyo3::class::impl_::*;
+        use pyo3::impl_::pyclass::*;
         let collector = PyClassImplCollector::<Self>::new();
         collector.free_impl()
     }
     fn for_each_proto_slot(visitor: &mut dyn FnMut(&[pyo3::ffi::PyType_Slot])) {
         // Implementation which uses dtolnay specialization to load all slots.
-        use pyo3::class::impl_::*;
+        use pyo3::impl_::pyclass::*;
         let collector = PyClassImplCollector::<Self>::new();
         visitor(collector.object_protocol_slots());
         visitor(collector.number_protocol_slots());
diff --git a/guide/src/features.md b/guide/src/features.md
index 1a29885c..e96b486b 100644
--- a/guide/src/features.md
+++ b/guide/src/features.md
@@ -65,6 +65,12 @@ Most users should only need a single `#[pymethods]` per `#[pyclass]`. In additio
 
 See [the `#[pyclass]` implementation details](class.md#implementation-details) for more information.
 
+### `pyproto`
+
+This feature enables the `#[pyproto]` macro, which is an alternative (older, soon-to-be-deprecated) to `#[pymethods]` for defining magic methods such as `__eq__`.
+
+> This feature is enabled by default. To disable it, set `default-features = false` for the `pyo3` entry in your Cargo.toml.
+
 ### `nightly`
 
 The `nightly` feature needs the nightly Rust compiler. This allows PyO3 to use Rust's unstable specialization feature to apply the following optimizations:
diff --git a/pyo3-macros-backend/Cargo.toml b/pyo3-macros-backend/Cargo.toml
index 5abd99af..f46a0848 100644
--- a/pyo3-macros-backend/Cargo.toml
+++ b/pyo3-macros-backend/Cargo.toml
@@ -22,3 +22,6 @@ pyo3-build-config = { path = "../pyo3-build-config", version = "0.15.1", feature
 version = "1"
 default-features = false
 features = ["derive", "parsing", "printing", "clone-impls", "full", "extra-traits"]
+
+[features]
+pyproto = []
diff --git a/pyo3-macros-backend/src/lib.rs b/pyo3-macros-backend/src/lib.rs
index c6419427..fd6ec4a4 100644
--- a/pyo3-macros-backend/src/lib.rs
+++ b/pyo3-macros-backend/src/lib.rs
@@ -9,6 +9,7 @@
 mod utils;
 
 mod attributes;
+#[cfg(feature = "pyproto")]
 mod defs;
 mod deprecations;
 mod frompyobject;
@@ -16,11 +17,13 @@ mod konst;
 mod method;
 mod module;
 mod params;
+#[cfg(feature = "pyproto")]
 mod proto_method;
 mod pyclass;
 mod pyfunction;
 mod pyimpl;
 mod pymethod;
+#[cfg(feature = "pyproto")]
 mod pyproto;
 mod wrap;
 
@@ -29,6 +32,7 @@ pub use module::{process_functions_in_module, pymodule_impl, PyModuleOptions};
 pub use pyclass::{build_py_class, build_py_enum, PyClassArgs};
 pub use pyfunction::{build_py_function, PyFunctionOptions};
 pub use pyimpl::{build_py_methods, PyClassMethodsType};
+#[cfg(feature = "pyproto")]
 pub use pyproto::build_py_proto;
 pub use utils::get_doc;
 pub use wrap::{wrap_pyfunction_impl, wrap_pymodule_impl, WrapPyFunctionArgs};
diff --git a/pyo3-macros-backend/src/method.rs b/pyo3-macros-backend/src/method.rs
index 930b005b..8d03d75c 100644
--- a/pyo3-macros-backend/src/method.rs
+++ b/pyo3-macros-backend/src/method.rs
@@ -566,23 +566,23 @@ impl<'a> FnSpec<'a> {
         let doc = &self.doc;
         match self.convention {
             CallingConvention::Noargs => quote! {
-                _pyo3::class::methods::PyMethodDef::noargs(
+                _pyo3::impl_::pymethods::PyMethodDef::noargs(
                     #python_name,
-                    _pyo3::class::methods::PyCFunction(#wrapper),
+                    _pyo3::impl_::pymethods::PyCFunction(#wrapper),
                     #doc,
                 )
             },
             CallingConvention::Fastcall => quote! {
-                _pyo3::class::methods::PyMethodDef::fastcall_cfunction_with_keywords(
+                _pyo3::impl_::pymethods::PyMethodDef::fastcall_cfunction_with_keywords(
                     #python_name,
-                    _pyo3::class::methods::PyCFunctionFastWithKeywords(#wrapper),
+                    _pyo3::impl_::pymethods::PyCFunctionFastWithKeywords(#wrapper),
                     #doc,
                 )
             },
             CallingConvention::Varargs => quote! {
-                _pyo3::class::methods::PyMethodDef::cfunction_with_keywords(
+                _pyo3::impl_::pymethods::PyMethodDef::cfunction_with_keywords(
                     #python_name,
-                    _pyo3::class::methods::PyCFunctionWithKeywords(#wrapper),
+                    _pyo3::impl_::pymethods::PyCFunctionWithKeywords(#wrapper),
                     #doc,
                 )
             },
diff --git a/pyo3-macros-backend/src/pyclass.rs b/pyo3-macros-backend/src/pyclass.rs
index 3a32f4be..462b8a3c 100644
--- a/pyo3-macros-backend/src/pyclass.rs
+++ b/pyo3-macros-backend/src/pyclass.rs
@@ -511,11 +511,11 @@ fn unit_variants_as_descriptors<'a>(
         .map(|var| gen_py_const(&cls_type, &variant_to_attribute(var)));
 
     quote! {
-        impl _pyo3::class::impl_::PyClassDescriptors<#cls>
-            for _pyo3::class::impl_::PyClassImplCollector<#cls>
+        impl _pyo3::impl_::pyclass::PyClassDescriptors<#cls>
+            for _pyo3::impl_::pyclass::PyClassImplCollector<#cls>
         {
-            fn py_class_descriptors(self) -> &'static [_pyo3::class::methods::PyMethodDefType] {
-                static METHODS: &[_pyo3::class::methods::PyMethodDefType] = &[#(#py_methods),*];
+            fn py_class_descriptors(self) -> &'static [_pyo3::impl_::pymethods::PyMethodDefType] {
+                static METHODS: &[_pyo3::impl_::pymethods::PyMethodDefType] = &[#(#py_methods),*];
                 METHODS
             }
         }
@@ -574,11 +574,11 @@ fn impl_descriptors(
         .collect::<syn::Result<_>>()?;
 
     Ok(quote! {
-        impl _pyo3::class::impl_::PyClassDescriptors<#cls>
-            for _pyo3::class::impl_::PyClassImplCollector<#cls>
+        impl _pyo3::impl_::pyclass::PyClassDescriptors<#cls>
+            for _pyo3::impl_::pyclass::PyClassImplCollector<#cls>
         {
-            fn py_class_descriptors(self) -> &'static [_pyo3::class::methods::PyMethodDefType] {
-                static METHODS: &[_pyo3::class::methods::PyMethodDefType] = &[#(#py_methods),*];
+            fn py_class_descriptors(self) -> &'static [_pyo3::impl_::pymethods::PyMethodDefType] {
+                static METHODS: &[_pyo3::impl_::pymethods::PyMethodDefType] = &[#(#py_methods),*];
                 METHODS
             }
         }
@@ -676,7 +676,7 @@ impl<'a> PyClassImplsBuilder<'a> {
         };
 
         let base_nativetype = if attr.has_extends {
-            quote! { <Self::BaseType as _pyo3::class::impl_::PyClassBaseType>::BaseNativeType }
+            quote! { <Self::BaseType as _pyo3::impl_::pyclass::PyClassBaseType>::BaseNativeType }
         } else {
             quote! { _pyo3::PyAny }
         };
@@ -749,13 +749,13 @@ impl<'a> PyClassImplsBuilder<'a> {
         };
 
         let thread_checker = if self.attr.has_unsendable {
-            quote! { _pyo3::class::impl_::ThreadCheckerImpl<#cls> }
+            quote! { _pyo3::impl_::pyclass::ThreadCheckerImpl<#cls> }
         } else if self.attr.has_extends {
             quote! {
-                _pyo3::class::impl_::ThreadCheckerInherited<#cls, <#cls as _pyo3::class::impl_::PyClassImpl>::BaseType>
+                _pyo3::impl_::pyclass::ThreadCheckerInherited<#cls, <#cls as _pyo3::impl_::pyclass::PyClassImpl>::BaseType>
             }
         } else {
-            quote! { _pyo3::class::impl_::ThreadCheckerStub<#cls> }
+            quote! { _pyo3::impl_::pyclass::ThreadCheckerStub<#cls> }
         };
 
         let (for_each_py_method, methods_protos, inventory, inventory_class) = match self
@@ -775,13 +775,13 @@ impl<'a> PyClassImplsBuilder<'a> {
                 );
                 (
                     quote! {
-                        for inventory in _pyo3::inventory::iter::<<Self as _pyo3::class::impl_::PyClassImpl>::Inventory>() {
-                            visitor(_pyo3::class::impl_::PyClassInventory::methods(inventory));
+                        for inventory in _pyo3::inventory::iter::<<Self as _pyo3::impl_::pyclass::PyClassImpl>::Inventory>() {
+                            visitor(_pyo3::impl_::pyclass::PyClassInventory::methods(inventory));
                         }
                     },
                     quote! {
-                        for inventory in _pyo3::inventory::iter::<<Self as _pyo3::class::impl_::PyClassImpl>::Inventory>() {
-                            visitor(_pyo3::class::impl_::PyClassInventory::slots(inventory));
+                        for inventory in _pyo3::inventory::iter::<<Self as _pyo3::impl_::pyclass::PyClassImpl>::Inventory>() {
+                            visitor(_pyo3::impl_::pyclass::PyClassInventory::slots(inventory));
                         }
                     },
                     Some(quote! { type Inventory = #inventory_class_name; }),
@@ -789,8 +789,37 @@ impl<'a> PyClassImplsBuilder<'a> {
                 )
             }
         };
+
+        let pyproto_method_visitors = if cfg!(feature = "pyproto") {
+            Some(quote! {
+                visitor(collector.object_protocol_methods());
+                visitor(collector.async_protocol_methods());
+                visitor(collector.descr_protocol_methods());
+                visitor(collector.mapping_protocol_methods());
+                visitor(collector.number_protocol_methods());
+            })
+        } else {
+            None
+        };
+
+        let pyproto_proto_visitors = if cfg!(feature = "pyproto") {
+            Some(quote! {
+                visitor(collector.object_protocol_slots());
+                visitor(collector.number_protocol_slots());
+                visitor(collector.iter_protocol_slots());
+                visitor(collector.gc_protocol_slots());
+                visitor(collector.descr_protocol_slots());
+                visitor(collector.mapping_protocol_slots());
+                visitor(collector.sequence_protocol_slots());
+                visitor(collector.async_protocol_slots());
+                visitor(collector.buffer_protocol_slots());
+            })
+        } else {
+            None
+        };
+
         quote! {
-            impl _pyo3::class::impl_::PyClassImpl for #cls {
+            impl _pyo3::impl_::pyclass::PyClassImpl for #cls {
                 const DOC: &'static str = #doc;
                 const IS_GC: bool = #is_gc;
                 const IS_BASETYPE: bool = #is_basetype;
@@ -802,48 +831,36 @@ impl<'a> PyClassImplsBuilder<'a> {
                 #inventory
 
                 fn for_each_method_def(visitor: &mut dyn ::std::ops::FnMut(&[_pyo3::class::PyMethodDefType])) {
-                    use _pyo3::class::impl_::*;
+                    use _pyo3::impl_::pyclass::*;
                     let collector = PyClassImplCollector::<Self>::new();
                     #for_each_py_method;
                     visitor(collector.py_class_descriptors());
-                    visitor(collector.object_protocol_methods());
-                    visitor(collector.async_protocol_methods());
-                    visitor(collector.descr_protocol_methods());
-                    visitor(collector.mapping_protocol_methods());
-                    visitor(collector.number_protocol_methods());
+                    #pyproto_method_visitors
                 }
                 fn get_new() -> ::std::option::Option<_pyo3::ffi::newfunc> {
-                    use _pyo3::class::impl_::*;
+                    use _pyo3::impl_::pyclass::*;
                     let collector = PyClassImplCollector::<Self>::new();
                     collector.new_impl()
                 }
                 fn get_alloc() -> ::std::option::Option<_pyo3::ffi::allocfunc> {
-                    use _pyo3::class::impl_::*;
+                    use _pyo3::impl_::pyclass::*;
                     let collector = PyClassImplCollector::<Self>::new();
                     collector.alloc_impl()
                 }
                 fn get_free() -> ::std::option::Option<_pyo3::ffi::freefunc> {
-                    use _pyo3::class::impl_::*;
+                    use _pyo3::impl_::pyclass::*;
                     let collector = PyClassImplCollector::<Self>::new();
                     collector.free_impl()
                 }
 
                 fn for_each_proto_slot(visitor: &mut dyn ::std::ops::FnMut(&[_pyo3::ffi::PyType_Slot])) {
                     // Implementation which uses dtolnay specialization to load all slots.
-                    use _pyo3::class::impl_::*;
+                    use _pyo3::impl_::pyclass::*;
                     let collector = PyClassImplCollector::<Self>::new();
                     // This depends on Python implementation detail;
                     // an old slot entry will be overriden by newer ones.
                     visitor(collector.py_class_default_slots());
-                    visitor(collector.object_protocol_slots());
-                    visitor(collector.number_protocol_slots());
-                    visitor(collector.iter_protocol_slots());
-                    visitor(collector.gc_protocol_slots());
-                    visitor(collector.descr_protocol_slots());
-                    visitor(collector.mapping_protocol_slots());
-                    visitor(collector.sequence_protocol_slots());
-                    visitor(collector.async_protocol_slots());
-                    visitor(collector.buffer_protocol_slots());
+                    #pyproto_proto_visitors
                     #methods_protos
                 }
 
@@ -861,7 +878,7 @@ impl<'a> PyClassImplsBuilder<'a> {
 
         self.attr.freelist.as_ref().map_or(quote!{}, |freelist| {
             quote! {
-                impl _pyo3::class::impl_::PyClassWithFreeList for #cls {
+                impl _pyo3::impl_::pyclass::PyClassWithFreeList for #cls {
                     #[inline]
                     fn get_free_list(_py: _pyo3::Python<'_>) -> &mut _pyo3::impl_::freelist::FreeList<*mut _pyo3::ffi::PyObject> {
                         static mut FREELIST: *mut _pyo3::impl_::freelist::FreeList<*mut _pyo3::ffi::PyObject> = 0 as *mut _;
@@ -875,17 +892,17 @@ impl<'a> PyClassImplsBuilder<'a> {
                     }
                 }
 
-                impl _pyo3::class::impl_::PyClassAllocImpl<#cls> for _pyo3::class::impl_::PyClassImplCollector<#cls> {
+                impl _pyo3::impl_::pyclass::PyClassAllocImpl<#cls> for _pyo3::impl_::pyclass::PyClassImplCollector<#cls> {
                     #[inline]
                     fn alloc_impl(self) -> ::std::option::Option<_pyo3::ffi::allocfunc> {
-                        ::std::option::Option::Some(_pyo3::class::impl_::alloc_with_freelist::<#cls>)
+                        ::std::option::Option::Some(_pyo3::impl_::pyclass::alloc_with_freelist::<#cls>)
                     }
                 }
 
-                impl _pyo3::class::impl_::PyClassFreeImpl<#cls> for _pyo3::class::impl_::PyClassImplCollector<#cls> {
+                impl _pyo3::impl_::pyclass::PyClassFreeImpl<#cls> for _pyo3::impl_::pyclass::PyClassImplCollector<#cls> {
                     #[inline]
                     fn free_impl(self) -> ::std::option::Option<_pyo3::ffi::freefunc> {
-                        ::std::option::Option::Some(_pyo3::class::impl_::free_with_freelist::<#cls>)
+                        ::std::option::Option::Some(_pyo3::impl_::pyclass::free_with_freelist::<#cls>)
                     }
                 }
             }
@@ -928,7 +945,7 @@ fn define_inventory_class(inventory_class_name: &syn::Ident) -> TokenStream {
             }
         }
 
-        impl _pyo3::class::impl_::PyClassInventory for #inventory_class_name {
+        impl _pyo3::impl_::pyclass::PyClassInventory for #inventory_class_name {
             fn methods(&'static self) -> &'static [_pyo3::class::PyMethodDefType] {
                 self.methods
             }
diff --git a/pyo3-macros-backend/src/pyimpl.rs b/pyo3-macros-backend/src/pyimpl.rs
index bb5a90f7..e2d0be19 100644
--- a/pyo3-macros-backend/src/pyimpl.rs
+++ b/pyo3-macros-backend/src/pyimpl.rs
@@ -190,7 +190,7 @@ pub fn gen_py_const(cls: &syn::Type, spec: &ConstSpec) -> TokenStream {
         _pyo3::class::PyMethodDefType::ClassAttribute({
             _pyo3::class::PyClassAttributeDef::new(
                 #python_name,
-                _pyo3::class::methods::PyClassAttributeFactory({
+                _pyo3::impl_::pymethods::PyClassAttributeFactory({
                     fn __wrap(py: _pyo3::Python<'_>) -> _pyo3::PyObject {
                         #deprecations
                         _pyo3::IntoPy::into_py(#cls::#member, py)
@@ -234,8 +234,8 @@ pub fn gen_default_slot_impls(cls: &syn::Ident, method_defs: Vec<TokenStream>) -
         impl #cls {
             #(#method_defs)*
         }
-        impl ::pyo3::class::impl_::PyClassDefaultSlots<#cls>
-            for ::pyo3::class::impl_::PyClassImplCollector<#cls> {
+        impl ::pyo3::impl_::pyclass::PyClassDefaultSlots<#cls>
+            for ::pyo3::impl_::pyclass::PyClassImplCollector<#cls> {
                 fn py_class_default_slots(self) -> &'static [::pyo3::ffi::PyType_Slot] {
                     &[#(#proto_impls),*]
                 }
@@ -245,11 +245,11 @@ pub fn gen_default_slot_impls(cls: &syn::Ident, method_defs: Vec<TokenStream>) -
 
 fn impl_py_methods(ty: &syn::Type, methods: Vec<TokenStream>) -> TokenStream {
     quote! {
-        impl _pyo3::class::impl_::PyMethods<#ty>
-            for _pyo3::class::impl_::PyClassImplCollector<#ty>
+        impl _pyo3::impl_::pyclass::PyMethods<#ty>
+            for _pyo3::impl_::pyclass::PyClassImplCollector<#ty>
         {
-            fn py_methods(self) -> &'static [_pyo3::class::methods::PyMethodDefType] {
-                static METHODS: &[_pyo3::class::methods::PyMethodDefType] = &[#(#methods),*];
+            fn py_methods(self) -> &'static [_pyo3::impl_::pymethods::PyMethodDefType] {
+                static METHODS: &[_pyo3::impl_::pymethods::PyMethodDefType] = &[#(#methods),*];
                 METHODS
             }
         }
@@ -266,7 +266,7 @@ fn add_shared_proto_slots(
             let first_implemented = implemented_proto_fragments.remove($first);
             let second_implemented = implemented_proto_fragments.remove($second);
             if first_implemented || second_implemented {
-                proto_impls.push(quote! { _pyo3::class::impl_::$slot!(#ty) })
+                proto_impls.push(quote! { _pyo3::impl_::pyclass::$slot!(#ty) })
             }
         }};
     }
@@ -300,8 +300,8 @@ fn add_shared_proto_slots(
 
 fn impl_protos(ty: &syn::Type, proto_impls: Vec<TokenStream>) -> TokenStream {
     quote! {
-        impl _pyo3::class::impl_::PyMethodsProtocolSlots<#ty>
-            for _pyo3::class::impl_::PyClassImplCollector<#ty>
+        impl _pyo3::impl_::pyclass::PyMethodsProtocolSlots<#ty>
+            for _pyo3::impl_::pyclass::PyClassImplCollector<#ty>
         {
             fn methods_protocol_slots(self) -> &'static [_pyo3::ffi::PyType_Slot] {
                 &[#(#proto_impls),*]
@@ -317,7 +317,7 @@ fn submit_methods_inventory(
 ) -> TokenStream {
     quote! {
         _pyo3::inventory::submit! {
-            type Inventory = <#ty as _pyo3::class::impl_::PyClassImpl>::Inventory;
+            type Inventory = <#ty as _pyo3::impl_::pyclass::PyClassImpl>::Inventory;
             Inventory::new(&[#(#methods),*], &[#(#proto_impls),*])
         }
     }
diff --git a/pyo3-macros-backend/src/pymethod.rs b/pyo3-macros-backend/src/pymethod.rs
index 57aac487..c4c901b8 100644
--- a/pyo3-macros-backend/src/pymethod.rs
+++ b/pyo3-macros-backend/src/pymethod.rs
@@ -194,7 +194,7 @@ fn impl_py_method_def_new(cls: &syn::Type, spec: &FnSpec) -> Result<TokenStream>
     let wrapper_ident = syn::Ident::new("__wrap", Span::call_site());
     let wrapper = spec.get_wrapper_function(&wrapper_ident, Some(cls))?;
     Ok(quote! {
-        impl _pyo3::class::impl_::PyClassNewImpl<#cls> for _pyo3::class::impl_::PyClassImplCollector<#cls> {
+        impl _pyo3::impl_::pyclass::PyClassNewImpl<#cls> for _pyo3::impl_::pyclass::PyClassImplCollector<#cls> {
             fn new_impl(self) -> ::std::option::Option<_pyo3::ffi::newfunc> {
                 ::std::option::Option::Some({
                     #wrapper
@@ -229,7 +229,7 @@ fn impl_py_class_attribute(cls: &syn::Type, spec: &FnSpec) -> TokenStream {
         _pyo3::class::PyMethodDefType::ClassAttribute({
             _pyo3::class::PyClassAttributeDef::new(
                 #python_name,
-                _pyo3::class::methods::PyClassAttributeFactory({
+                _pyo3::impl_::pymethods::PyClassAttributeFactory({
                     fn __wrap(py: _pyo3::Python<'_>) -> _pyo3::PyObject {
                         #deprecations
                         _pyo3::IntoPy::into_py(#cls::#name(), py)
@@ -299,7 +299,7 @@ pub fn impl_py_setter_def(cls: &syn::Type, property_type: PropertyType) -> Resul
             #deprecations
             _pyo3::class::PySetterDef::new(
                 #python_name,
-                _pyo3::class::methods::PySetter({
+                _pyo3::impl_::pymethods::PySetter({
                     unsafe extern "C" fn __wrap(
                         _slf: *mut _pyo3::ffi::PyObject,
                         _value: *mut _pyo3::ffi::PyObject,
@@ -379,7 +379,7 @@ pub fn impl_py_getter_def(cls: &syn::Type, property_type: PropertyType) -> Resul
             #deprecations
             _pyo3::class::PyGetterDef::new(
                 #python_name,
-                _pyo3::class::methods::PyGetter({
+                _pyo3::impl_::pymethods::PyGetter({
                     unsafe extern "C" fn __wrap(
                         _slf: *mut _pyo3::ffi::PyObject,
                         _: *mut ::std::os::raw::c_void
@@ -972,7 +972,7 @@ impl SlotFragmentDef {
         let body = generate_method_body(cls, spec, &py, arguments, *extract_error_mode, None)?;
         let ret_ty = ret_ty.ffi_type();
         Ok(quote! {
-            impl _pyo3::class::impl_::#fragment_trait<#cls> for _pyo3::class::impl_::PyClassImplCollector<#cls> {
+            impl _pyo3::impl_::pyclass::#fragment_trait<#cls> for _pyo3::impl_::pyclass::PyClassImplCollector<#cls> {
 
                 #[inline]
                 unsafe fn #method(
diff --git a/pyo3-macros-backend/src/pyproto.rs b/pyo3-macros-backend/src/pyproto.rs
index 198fb517..3c7973ac 100644
--- a/pyo3-macros-backend/src/pyproto.rs
+++ b/pyo3-macros-backend/src/pyproto.rs
@@ -109,11 +109,11 @@ fn impl_normal_methods(
     let methods_trait = proto.methods_trait();
     let methods_trait_methods = proto.methods_trait_methods();
     quote! {
-        impl _pyo3::class::impl_::#methods_trait<#ty>
-            for _pyo3::class::impl_::PyClassImplCollector<#ty>
+        impl _pyo3::impl_::pyclass::#methods_trait<#ty>
+            for _pyo3::impl_::pyclass::PyClassImplCollector<#ty>
         {
-            fn #methods_trait_methods(self) -> &'static [_pyo3::class::methods::PyMethodDefType] {
-                static METHODS: &[_pyo3::class::methods::PyMethodDefType] =
+            fn #methods_trait_methods(self) -> &'static [_pyo3::impl_::pymethods::PyMethodDefType] {
+                static METHODS: &[_pyo3::impl_::pymethods::PyMethodDefType] =
                     &[#(#py_methods),*];
                 METHODS
             }
@@ -153,8 +153,8 @@ fn impl_proto_methods(
     }
 
     quote! {
-        impl _pyo3::class::impl_::#slots_trait<#ty>
-            for _pyo3::class::impl_::PyClassImplCollector<#ty>
+        impl _pyo3::impl_::pyclass::#slots_trait<#ty>
+            for _pyo3::impl_::pyclass::PyClassImplCollector<#ty>
         {
             fn #slots_trait_slots(self) -> &'static [_pyo3::ffi::PyType_Slot] {
                 &[#(#tokens),*]
diff --git a/pyo3-macros/Cargo.toml b/pyo3-macros/Cargo.toml
index 6f55d41a..a12d7d7c 100644
--- a/pyo3-macros/Cargo.toml
+++ b/pyo3-macros/Cargo.toml
@@ -16,6 +16,8 @@ proc-macro = true
 [features]
 multiple-pymethods = []
 
+pyproto = ["pyo3-macros-backend/pyproto"]
+
 [dependencies]
 proc-macro2 = { version = "1", default-features = false }
 quote = "1"
diff --git a/pyo3-macros/src/lib.rs b/pyo3-macros/src/lib.rs
index c03d3c86..54070202 100644
--- a/pyo3-macros/src/lib.rs
+++ b/pyo3-macros/src/lib.rs
@@ -9,9 +9,8 @@ use proc_macro::TokenStream;
 use proc_macro2::TokenStream as TokenStream2;
 use pyo3_macros_backend::{
     build_derive_from_pyobject, build_py_class, build_py_enum, build_py_function, build_py_methods,
-    build_py_proto, get_doc, process_functions_in_module, pymodule_impl, wrap_pyfunction_impl,
-    wrap_pymodule_impl, PyClassArgs, PyClassMethodsType, PyFunctionOptions, PyModuleOptions,
-    WrapPyFunctionArgs,
+    get_doc, process_functions_in_module, pymodule_impl, wrap_pyfunction_impl, wrap_pymodule_impl,
+    PyClassArgs, PyClassMethodsType, PyFunctionOptions, PyModuleOptions, WrapPyFunctionArgs,
 };
 use quote::quote;
 use syn::{parse::Nothing, parse_macro_input};
@@ -68,9 +67,10 @@ pub fn pymodule(args: TokenStream, input: TokenStream) -> TokenStream {
 /// [4]: ../class/gc/trait.PyGCProtocol.html
 /// [5]: ../class/iter/trait.PyIterProtocol.html
 #[proc_macro_attribute]
+#[cfg(feature = "pyproto")]
 pub fn pyproto(_: TokenStream, input: TokenStream) -> TokenStream {
     let mut ast = parse_macro_input!(input as syn::ItemImpl);
-    let expanded = build_py_proto(&mut ast).unwrap_or_compile_error();
+    let expanded = pyo3_macros_backend::build_py_proto(&mut ast).unwrap_or_compile_error();
 
     quote!(
         #ast
diff --git a/pytests/src/subclassing.rs b/pytests/src/subclassing.rs
index d54bbc4d..8fd111e0 100644
--- a/pytests/src/subclassing.rs
+++ b/pytests/src/subclassing.rs
@@ -11,10 +11,7 @@ impl Subclassable {
     fn new() -> Self {
         Subclassable {}
     }
-}
 
-#[pyproto]
-impl pyo3::PyObjectProtocol for Subclassable {
     fn __str__(&self) -> PyResult<&'static str> {
         Ok("Subclassable")
     }
diff --git a/src/class/basic.rs b/src/class/basic.rs
index 9d4d569b..b2d0e9ab 100644
--- a/src/class/basic.rs
+++ b/src/class/basic.rs
@@ -12,37 +12,6 @@ use crate::callback::{HashCallbackOutput, IntoPyCallbackOutput};
 use crate::{exceptions, ffi, FromPyObject, PyAny, PyCell, PyClass, PyObject};
 use std::os::raw::c_int;
 
-/// Operators for the `__richcmp__` method
-#[derive(Debug, Clone, Copy)]
-pub enum CompareOp {
-    /// The *less than* operator.
-    Lt = ffi::Py_LT as isize,
-    /// The *less than or equal to* operator.
-    Le = ffi::Py_LE as isize,
-    /// The equality operator.
-    Eq = ffi::Py_EQ as isize,
-    /// The *not equal to* operator.
-    Ne = ffi::Py_NE as isize,
-    /// The *greater than* operator.
-    Gt = ffi::Py_GT as isize,
-    /// The *greater than or equal to* operator.
-    Ge = ffi::Py_GE as isize,
-}
-
-impl CompareOp {
-    pub fn from_raw(op: c_int) -> Option<Self> {
-        match op {
-            ffi::Py_LT => Some(CompareOp::Lt),
-            ffi::Py_LE => Some(CompareOp::Le),
-            ffi::Py_EQ => Some(CompareOp::Eq),
-            ffi::Py_NE => Some(CompareOp::Ne),
-            ffi::Py_GT => Some(CompareOp::Gt),
-            ffi::Py_GE => Some(CompareOp::Ge),
-            _ => None,
-        }
-    }
-}
-
 /// Basic Python class customization
 #[allow(unused_variables)]
 pub trait PyObjectProtocol<'p>: PyClass {
@@ -202,3 +171,5 @@ py_func_set_del!(
     __delattr__
 );
 py_unary_func!(bool, PyObjectBoolProtocol, T::__bool__, c_int);
+
+pub use crate::pyclass::CompareOp;
diff --git a/src/class/impl_.rs b/src/class/impl_.rs
deleted file mode 100644
index a3041da9..00000000
--- a/src/class/impl_.rs
+++ /dev/null
@@ -1,818 +0,0 @@
-// Copyright (c) 2017-present PyO3 Project and Contributors
-
-use crate::{
-    exceptions::{PyAttributeError, PyNotImplementedError},
-    ffi,
-    impl_::freelist::FreeList,
-    pycell::PyCellLayout,
-    pyclass_init::PyObjectInit,
-    type_object::{PyLayout, PyTypeObject},
-    PyClass, PyMethodDefType, PyNativeType, PyResult, PyTypeInfo, Python,
-};
-use std::{
-    marker::PhantomData,
-    os::raw::{c_int, c_void},
-    ptr::NonNull,
-    thread,
-};
-
-/// This type is used as a "dummy" type on which dtolnay specializations are
-/// applied to apply implementations from `#[pymethods]` & `#[pyproto]`
-pub struct PyClassImplCollector<T>(PhantomData<T>);
-
-impl<T> PyClassImplCollector<T> {
-    pub fn new() -> Self {
-        Self(PhantomData)
-    }
-}
-
-impl<T> Default for PyClassImplCollector<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> Clone for PyClassImplCollector<T> {
-    fn clone(&self) -> Self {
-        Self::new()
-    }
-}
-
-impl<T> Copy for PyClassImplCollector<T> {}
-
-/// Implements the underlying functionality of `#[pyclass]`, assembled by various proc macros.
-///
-/// Users are discouraged from implementing this trait manually; it is a PyO3 implementation detail
-/// and may be changed at any time.
-pub trait PyClassImpl: Sized {
-    /// Class doc string
-    const DOC: &'static str = "\0";
-
-    /// #[pyclass(gc)]
-    const IS_GC: bool = false;
-
-    /// #[pyclass(subclass)]
-    const IS_BASETYPE: bool = false;
-
-    /// #[pyclass(extends=...)]
-    const IS_SUBCLASS: bool = false;
-
-    /// Layout
-    type Layout: PyLayout<Self>;
-
-    /// Base class
-    type BaseType: PyTypeInfo + PyTypeObject + PyClassBaseType;
-
-    /// This handles following two situations:
-    /// 1. In case `T` is `Send`, stub `ThreadChecker` is used and does nothing.
-    ///    This implementation is used by default. Compile fails if `T: !Send`.
-    /// 2. In case `T` is `!Send`, `ThreadChecker` panics when `T` is accessed by another thread.
-    ///    This implementation is used when `#[pyclass(unsendable)]` is given.
-    ///    Panicking makes it safe to expose `T: !Send` to the Python interpreter, where all objects
-    ///    can be accessed by multiple threads by `threading` module.
-    type ThreadChecker: PyClassThreadChecker<Self>;
-
-    #[cfg(feature = "multiple-pymethods")]
-    type Inventory: PyClassInventory;
-
-    fn for_each_method_def(_visitor: &mut dyn FnMut(&[PyMethodDefType])) {}
-    fn for_each_proto_slot(_visitor: &mut dyn FnMut(&[ffi::PyType_Slot])) {}
-
-    #[inline]
-    fn get_new() -> Option<ffi::newfunc> {
-        None
-    }
-    #[inline]
-    fn get_alloc() -> Option<ffi::allocfunc> {
-        None
-    }
-    #[inline]
-    fn get_free() -> Option<ffi::freefunc> {
-        None
-    }
-    #[inline]
-    fn dict_offset() -> Option<ffi::Py_ssize_t> {
-        None
-    }
-    #[inline]
-    fn weaklist_offset() -> Option<ffi::Py_ssize_t> {
-        None
-    }
-}
-
-// Traits describing known special methods.
-
-pub trait PyClassNewImpl<T> {
-    fn new_impl(self) -> Option<ffi::newfunc>;
-}
-
-impl<T> PyClassNewImpl<T> for &'_ PyClassImplCollector<T> {
-    fn new_impl(self) -> Option<ffi::newfunc> {
-        None
-    }
-}
-
-macro_rules! slot_fragment_trait {
-    ($trait_name:ident, $($default_method:tt)*) => {
-        #[allow(non_camel_case_types)]
-        pub trait $trait_name<T>: Sized {
-            $($default_method)*
-        }
-
-        impl<T> $trait_name<T> for &'_ PyClassImplCollector<T> {}
-    }
-}
-
-/// Macro which expands to three items
-/// - Trait for a __setitem__ dunder
-/// - Trait for the corresponding __delitem__ dunder
-/// - A macro which will use dtolnay specialisation to generate the shared slot for the two dunders
-macro_rules! define_pyclass_setattr_slot {
-    (
-        $set_trait:ident,
-        $del_trait:ident,
-        $set:ident,
-        $del:ident,
-        $set_error:expr,
-        $del_error:expr,
-        $generate_macro:ident,
-        $slot:ident,
-        $func_ty:ident,
-    ) => {
-        slot_fragment_trait! {
-            $set_trait,
-
-            /// # Safety: _slf and _attr must be valid non-null Python objects
-            #[inline]
-            unsafe fn $set(
-                self,
-                _py: Python,
-                _slf: *mut ffi::PyObject,
-                _attr: *mut ffi::PyObject,
-                _value: NonNull<ffi::PyObject>,
-            ) -> PyResult<()> {
-                $set_error
-            }
-        }
-
-        slot_fragment_trait! {
-            $del_trait,
-
-            /// # Safety: _slf and _attr must be valid non-null Python objects
-            #[inline]
-            unsafe fn $del(
-                self,
-                _py: Python,
-                _slf: *mut ffi::PyObject,
-                _attr: *mut ffi::PyObject,
-            ) -> PyResult<()> {
-                $del_error
-            }
-        }
-
-        #[doc(hidden)]
-        #[macro_export]
-        macro_rules! $generate_macro {
-            ($cls:ty) => {{
-                unsafe extern "C" fn __wrap(
-                    _slf: *mut $crate::ffi::PyObject,
-                    attr: *mut $crate::ffi::PyObject,
-                    value: *mut $crate::ffi::PyObject,
-                ) -> ::std::os::raw::c_int {
-                    use ::std::option::Option::*;
-                    use $crate::callback::IntoPyCallbackOutput;
-                    use $crate::class::impl_::*;
-                    $crate::callback::handle_panic(|py| {
-                        let collector = PyClassImplCollector::<$cls>::new();
-                        if let Some(value) = ::std::ptr::NonNull::new(value) {
-                            collector.$set(py, _slf, attr, value).convert(py)
-                        } else {
-                            collector.$del(py, _slf, attr).convert(py)
-                        }
-                    })
-                }
-                $crate::ffi::PyType_Slot {
-                    slot: $crate::ffi::$slot,
-                    pfunc: __wrap as $crate::ffi::$func_ty as _,
-                }
-            }};
-        }
-        pub use $generate_macro;
-    };
-}
-
-define_pyclass_setattr_slot! {
-    PyClass__setattr__SlotFragment,
-    PyClass__delattr__SlotFragment,
-    __setattr__,
-    __delattr__,
-    Err(PyAttributeError::new_err("can't set attribute")),
-    Err(PyAttributeError::new_err("can't delete attribute")),
-    generate_pyclass_setattr_slot,
-    Py_tp_setattro,
-    setattrofunc,
-}
-
-define_pyclass_setattr_slot! {
-    PyClass__set__SlotFragment,
-    PyClass__delete__SlotFragment,
-    __set__,
-    __delete__,
-    Err(PyNotImplementedError::new_err("can't set descriptor")),
-    Err(PyNotImplementedError::new_err("can't delete descriptor")),
-    generate_pyclass_setdescr_slot,
-    Py_tp_descr_set,
-    descrsetfunc,
-}
-
-define_pyclass_setattr_slot! {
-    PyClass__setitem__SlotFragment,
-    PyClass__delitem__SlotFragment,
-    __setitem__,
-    __delitem__,
-    Err(PyNotImplementedError::new_err("can't set item")),
-    Err(PyNotImplementedError::new_err("can't delete item")),
-    generate_pyclass_setitem_slot,
-    Py_mp_ass_subscript,
-    objobjargproc,
-}
-
-/// Macro which expands to three items
-/// - Trait for a lhs dunder e.g. __add__
-/// - Trait for the corresponding rhs e.g. __radd__
-/// - A macro which will use dtolnay specialisation to generate the shared slot for the two dunders
-macro_rules! define_pyclass_binary_operator_slot {
-    (
-        $lhs_trait:ident,
-        $rhs_trait:ident,
-        $lhs:ident,
-        $rhs:ident,
-        $generate_macro:ident,
-        $slot:ident,
-        $func_ty:ident,
-    ) => {
-        slot_fragment_trait! {
-            $lhs_trait,
-
-            /// # Safety: _slf and _other must be valid non-null Python objects
-            #[inline]
-            unsafe fn $lhs(
-                self,
-                _py: Python,
-                _slf: *mut ffi::PyObject,
-                _other: *mut ffi::PyObject,
-            ) -> PyResult<*mut ffi::PyObject> {
-                Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
-            }
-        }
-
-        slot_fragment_trait! {
-            $rhs_trait,
-
-            /// # Safety: _slf and _other must be valid non-null Python objects
-            #[inline]
-            unsafe fn $rhs(
-                self,
-                _py: Python,
-                _slf: *mut ffi::PyObject,
-                _other: *mut ffi::PyObject,
-            ) -> PyResult<*mut ffi::PyObject> {
-                Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
-            }
-        }
-
-        #[doc(hidden)]
-        #[macro_export]
-        macro_rules! $generate_macro {
-            ($cls:ty) => {{
-                unsafe extern "C" fn __wrap(
-                    _slf: *mut $crate::ffi::PyObject,
-                    _other: *mut $crate::ffi::PyObject,
-                ) -> *mut $crate::ffi::PyObject {
-                    $crate::callback::handle_panic(|py| {
-                        use $crate::class::impl_::*;
-                        let collector = PyClassImplCollector::<$cls>::new();
-                        let lhs_result = collector.$lhs(py, _slf, _other)?;
-                        if lhs_result == $crate::ffi::Py_NotImplemented() {
-                            $crate::ffi::Py_DECREF(lhs_result);
-                            collector.$rhs(py, _other, _slf)
-                        } else {
-                            ::std::result::Result::Ok(lhs_result)
-                        }
-                    })
-                }
-                $crate::ffi::PyType_Slot {
-                    slot: $crate::ffi::$slot,
-                    pfunc: __wrap as $crate::ffi::$func_ty as _,
-                }
-            }};
-        }
-        pub use $generate_macro;
-    };
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__add__SlotFragment,
-    PyClass__radd__SlotFragment,
-    __add__,
-    __radd__,
-    generate_pyclass_add_slot,
-    Py_nb_add,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__sub__SlotFragment,
-    PyClass__rsub__SlotFragment,
-    __sub__,
-    __rsub__,
-    generate_pyclass_sub_slot,
-    Py_nb_subtract,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__mul__SlotFragment,
-    PyClass__rmul__SlotFragment,
-    __mul__,
-    __rmul__,
-    generate_pyclass_mul_slot,
-    Py_nb_multiply,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__mod__SlotFragment,
-    PyClass__rmod__SlotFragment,
-    __mod__,
-    __rmod__,
-    generate_pyclass_mod_slot,
-    Py_nb_remainder,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__divmod__SlotFragment,
-    PyClass__rdivmod__SlotFragment,
-    __divmod__,
-    __rdivmod__,
-    generate_pyclass_divmod_slot,
-    Py_nb_divmod,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__lshift__SlotFragment,
-    PyClass__rlshift__SlotFragment,
-    __lshift__,
-    __rlshift__,
-    generate_pyclass_lshift_slot,
-    Py_nb_lshift,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__rshift__SlotFragment,
-    PyClass__rrshift__SlotFragment,
-    __rshift__,
-    __rrshift__,
-    generate_pyclass_rshift_slot,
-    Py_nb_rshift,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__and__SlotFragment,
-    PyClass__rand__SlotFragment,
-    __and__,
-    __rand__,
-    generate_pyclass_and_slot,
-    Py_nb_and,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__or__SlotFragment,
-    PyClass__ror__SlotFragment,
-    __or__,
-    __ror__,
-    generate_pyclass_or_slot,
-    Py_nb_or,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__xor__SlotFragment,
-    PyClass__rxor__SlotFragment,
-    __xor__,
-    __rxor__,
-    generate_pyclass_xor_slot,
-    Py_nb_xor,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__matmul__SlotFragment,
-    PyClass__rmatmul__SlotFragment,
-    __matmul__,
-    __rmatmul__,
-    generate_pyclass_matmul_slot,
-    Py_nb_matrix_multiply,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__truediv__SlotFragment,
-    PyClass__rtruediv__SlotFragment,
-    __truediv__,
-    __rtruediv__,
-    generate_pyclass_truediv_slot,
-    Py_nb_true_divide,
-    binaryfunc,
-}
-
-define_pyclass_binary_operator_slot! {
-    PyClass__floordiv__SlotFragment,
-    PyClass__rfloordiv__SlotFragment,
-    __floordiv__,
-    __rfloordiv__,
-    generate_pyclass_floordiv_slot,
-    Py_nb_floor_divide,
-    binaryfunc,
-}
-
-slot_fragment_trait! {
-    PyClass__pow__SlotFragment,
-
-    /// # Safety: _slf and _other must be valid non-null Python objects
-    #[inline]
-    unsafe fn __pow__(
-        self,
-        _py: Python,
-        _slf: *mut ffi::PyObject,
-        _other: *mut ffi::PyObject,
-        _mod: *mut ffi::PyObject,
-    ) -> PyResult<*mut ffi::PyObject> {
-        Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
-    }
-}
-
-slot_fragment_trait! {
-    PyClass__rpow__SlotFragment,
-
-    /// # Safety: _slf and _other must be valid non-null Python objects
-    #[inline]
-    unsafe fn __rpow__(
-        self,
-        _py: Python,
-        _slf: *mut ffi::PyObject,
-        _other: *mut ffi::PyObject,
-        _mod: *mut ffi::PyObject,
-    ) -> PyResult<*mut ffi::PyObject> {
-        Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
-    }
-}
-
-#[doc(hidden)]
-#[macro_export]
-macro_rules! generate_pyclass_pow_slot {
-    ($cls:ty) => {{
-        unsafe extern "C" fn __wrap(
-            _slf: *mut $crate::ffi::PyObject,
-            _other: *mut $crate::ffi::PyObject,
-            _mod: *mut $crate::ffi::PyObject,
-        ) -> *mut $crate::ffi::PyObject {
-            $crate::callback::handle_panic(|py| {
-                use $crate::class::impl_::*;
-                let collector = PyClassImplCollector::<$cls>::new();
-                let lhs_result = collector.__pow__(py, _slf, _other, _mod)?;
-                if lhs_result == $crate::ffi::Py_NotImplemented() {
-                    $crate::ffi::Py_DECREF(lhs_result);
-                    collector.__rpow__(py, _other, _slf, _mod)
-                } else {
-                    ::std::result::Result::Ok(lhs_result)
-                }
-            })
-        }
-        $crate::ffi::PyType_Slot {
-            slot: $crate::ffi::Py_nb_power,
-            pfunc: __wrap as $crate::ffi::ternaryfunc as _,
-        }
-    }};
-}
-pub use generate_pyclass_pow_slot;
-
-pub trait PyClassAllocImpl<T> {
-    fn alloc_impl(self) -> Option<ffi::allocfunc>;
-}
-
-impl<T> PyClassAllocImpl<T> for &'_ PyClassImplCollector<T> {
-    fn alloc_impl(self) -> Option<ffi::allocfunc> {
-        None
-    }
-}
-
-pub trait PyClassFreeImpl<T> {
-    fn free_impl(self) -> Option<ffi::freefunc>;
-}
-
-impl<T> PyClassFreeImpl<T> for &'_ PyClassImplCollector<T> {
-    fn free_impl(self) -> Option<ffi::freefunc> {
-        None
-    }
-}
-
-/// Implements a freelist.
-///
-/// Do not implement this trait manually. Instead, use `#[pyclass(freelist = N)]`
-/// on a Rust struct to implement it.
-pub trait PyClassWithFreeList: PyClass {
-    fn get_free_list(py: Python) -> &mut FreeList<*mut ffi::PyObject>;
-}
-
-/// Implementation of tp_alloc for `freelist` classes.
-///
-/// # Safety
-/// - `subtype` must be a valid pointer to the type object of T or a subclass.
-/// - The GIL must be held.
-pub unsafe extern "C" fn alloc_with_freelist<T: PyClassWithFreeList>(
-    subtype: *mut ffi::PyTypeObject,
-    nitems: ffi::Py_ssize_t,
-) -> *mut ffi::PyObject {
-    let py = Python::assume_gil_acquired();
-
-    #[cfg(not(Py_3_8))]
-    bpo_35810_workaround(py, subtype);
-
-    let self_type = T::type_object_raw(py);
-    // If this type is a variable type or the subtype is not equal to this type, we cannot use the
-    // freelist
-    if nitems == 0 && subtype == self_type {
-        if let Some(obj) = T::get_free_list(py).pop() {
-            ffi::PyObject_Init(obj, subtype);
-            return obj as _;
-        }
-    }
-
-    ffi::PyType_GenericAlloc(subtype, nitems)
-}
-
-/// Implementation of tp_free for `freelist` classes.
-///
-/// # Safety
-/// - `obj` must be a valid pointer to an instance of T (not a subclass).
-/// - The GIL must be held.
-pub unsafe extern "C" fn free_with_freelist<T: PyClassWithFreeList>(obj: *mut c_void) {
-    let obj = obj as *mut ffi::PyObject;
-    debug_assert_eq!(
-        T::type_object_raw(Python::assume_gil_acquired()),
-        ffi::Py_TYPE(obj)
-    );
-    if let Some(obj) = T::get_free_list(Python::assume_gil_acquired()).insert(obj) {
-        let ty = ffi::Py_TYPE(obj);
-
-        // Deduce appropriate inverse of PyType_GenericAlloc
-        let free = if ffi::PyType_IS_GC(ty) != 0 {
-            ffi::PyObject_GC_Del
-        } else {
-            ffi::PyObject_Free
-        };
-        free(obj as *mut c_void);
-
-        #[cfg(Py_3_8)]
-        if ffi::PyType_HasFeature(ty, ffi::Py_TPFLAGS_HEAPTYPE) != 0 {
-            ffi::Py_DECREF(ty as *mut ffi::PyObject);
-        }
-    }
-}
-
-/// Workaround for Python issue 35810; no longer necessary in Python 3.8
-#[inline]
-#[cfg(not(Py_3_8))]
-unsafe fn bpo_35810_workaround(_py: Python, ty: *mut ffi::PyTypeObject) {
-    #[cfg(Py_LIMITED_API)]
-    {
-        // Must check version at runtime for abi3 wheels - they could run against a higher version
-        // than the build config suggests.
-        use crate::once_cell::GILOnceCell;
-        static IS_PYTHON_3_8: GILOnceCell<bool> = GILOnceCell::new();
-
-        if *IS_PYTHON_3_8.get_or_init(_py, || _py.version_info() >= (3, 8)) {
-            // No fix needed - the wheel is running on a sufficiently new interpreter.
-            return;
-        }
-    }
-
-    ffi::Py_INCREF(ty as *mut ffi::PyObject);
-}
-
-// General methods implementation: either dtolnay specialization trait or inventory if
-// multiple-pymethods feature is enabled.
-
-macro_rules! methods_trait {
-    ($name:ident, $function_name: ident) => {
-        pub trait $name<T> {
-            fn $function_name(self) -> &'static [PyMethodDefType];
-        }
-
-        impl<T> $name<T> for &'_ PyClassImplCollector<T> {
-            fn $function_name(self) -> &'static [PyMethodDefType] {
-                &[]
-            }
-        }
-    };
-}
-
-/// Implementation detail. Only to be used through our proc macro code.
-/// Method storage for `#[pyclass]`.
-/// Allows arbitrary `#[pymethod]` blocks to submit their methods,
-/// which are eventually collected by `#[pyclass]`.
-#[cfg(feature = "multiple-pymethods")]
-pub trait PyClassInventory: inventory::Collect {
-    /// Returns the methods for a single `#[pymethods] impl` block
-    fn methods(&'static self) -> &'static [PyMethodDefType];
-
-    /// Returns the slots for a single `#[pymethods] impl` block
-    fn slots(&'static self) -> &'static [ffi::PyType_Slot];
-}
-
-// Methods from #[pyo3(get, set)] on struct fields.
-methods_trait!(PyClassDescriptors, py_class_descriptors);
-
-// Methods from #[pymethods] if not using inventory.
-#[cfg(not(feature = "multiple-pymethods"))]
-methods_trait!(PyMethods, py_methods);
-
-// All traits describing slots, as well as the fallback implementations for unimplemented protos
-//
-// Protos which are implemented use dtolnay specialization to implement for PyClassImplCollector<T>.
-//
-// See https://github.com/dtolnay/case-studies/blob/master/autoref-specialization/README.md
-
-macro_rules! slots_trait {
-    ($name:ident, $function_name: ident) => {
-        pub trait $name<T> {
-            fn $function_name(self) -> &'static [ffi::PyType_Slot];
-        }
-
-        impl<T> $name<T> for &'_ PyClassImplCollector<T> {
-            fn $function_name(self) -> &'static [ffi::PyType_Slot] {
-                &[]
-            }
-        }
-    };
-}
-
-slots_trait!(PyObjectProtocolSlots, object_protocol_slots);
-slots_trait!(PyDescrProtocolSlots, descr_protocol_slots);
-slots_trait!(PyGCProtocolSlots, gc_protocol_slots);
-slots_trait!(PyIterProtocolSlots, iter_protocol_slots);
-slots_trait!(PyMappingProtocolSlots, mapping_protocol_slots);
-slots_trait!(PyNumberProtocolSlots, number_protocol_slots);
-slots_trait!(PyAsyncProtocolSlots, async_protocol_slots);
-slots_trait!(PySequenceProtocolSlots, sequence_protocol_slots);
-slots_trait!(PyBufferProtocolSlots, buffer_protocol_slots);
-
-// slots that PyO3 implements by default, but can be overidden by the users.
-slots_trait!(PyClassDefaultSlots, py_class_default_slots);
-
-// Protocol slots from #[pymethods] if not using inventory.
-#[cfg(not(feature = "multiple-pymethods"))]
-slots_trait!(PyMethodsProtocolSlots, methods_protocol_slots);
-
-methods_trait!(PyObjectProtocolMethods, object_protocol_methods);
-methods_trait!(PyAsyncProtocolMethods, async_protocol_methods);
-methods_trait!(PyDescrProtocolMethods, descr_protocol_methods);
-methods_trait!(PyMappingProtocolMethods, mapping_protocol_methods);
-methods_trait!(PyNumberProtocolMethods, number_protocol_methods);
-
-// Thread checkers
-
-#[doc(hidden)]
-pub trait PyClassThreadChecker<T>: Sized {
-    fn ensure(&self);
-    fn new() -> Self;
-    private_decl! {}
-}
-
-/// Stub checker for `Send` types.
-#[doc(hidden)]
-pub struct ThreadCheckerStub<T: Send>(PhantomData<T>);
-
-impl<T: Send> PyClassThreadChecker<T> for ThreadCheckerStub<T> {
-    fn ensure(&self) {}
-    #[inline]
-    fn new() -> Self {
-        ThreadCheckerStub(PhantomData)
-    }
-    private_impl! {}
-}
-
-impl<T: PyNativeType> PyClassThreadChecker<T> for ThreadCheckerStub<crate::PyObject> {
-    fn ensure(&self) {}
-    #[inline]
-    fn new() -> Self {
-        ThreadCheckerStub(PhantomData)
-    }
-    private_impl! {}
-}
-
-/// Thread checker for unsendable types.
-/// Panics when the value is accessed by another thread.
-#[doc(hidden)]
-pub struct ThreadCheckerImpl<T>(thread::ThreadId, PhantomData<T>);
-
-impl<T> PyClassThreadChecker<T> for ThreadCheckerImpl<T> {
-    fn ensure(&self) {
-        if thread::current().id() != self.0 {
-            panic!(
-                "{} is unsendable, but sent to another thread!",
-                std::any::type_name::<T>()
-            );
-        }
-    }
-    fn new() -> Self {
-        ThreadCheckerImpl(thread::current().id(), PhantomData)
-    }
-    private_impl! {}
-}
-
-/// Thread checker for types that have `Send` and `extends=...`.
-/// Ensures that `T: Send` and the parent is not accessed by another thread.
-#[doc(hidden)]
-pub struct ThreadCheckerInherited<T: Send, U: PyClassBaseType>(PhantomData<T>, U::ThreadChecker);
-
-impl<T: Send, U: PyClassBaseType> PyClassThreadChecker<T> for ThreadCheckerInherited<T, U> {
-    fn ensure(&self) {
-        self.1.ensure();
-    }
-    fn new() -> Self {
-        ThreadCheckerInherited(PhantomData, U::ThreadChecker::new())
-    }
-    private_impl! {}
-}
-
-/// Trait denoting that this class is suitable to be used as a base type for PyClass.
-pub trait PyClassBaseType: Sized {
-    type LayoutAsBase: PyCellLayout<Self>;
-    type BaseNativeType;
-    type ThreadChecker: PyClassThreadChecker<Self>;
-    type Initializer: PyObjectInit<Self>;
-}
-
-/// All PyClasses can be used as a base type.
-impl<T: PyClass> PyClassBaseType for T {
-    type LayoutAsBase = crate::pycell::PyCell<T>;
-    type BaseNativeType = T::BaseNativeType;
-    type ThreadChecker = T::ThreadChecker;
-    type Initializer = crate::pyclass_init::PyClassInitializer<Self>;
-}
-
-/// Default new implementation
-pub(crate) unsafe extern "C" fn fallback_new(
-    _subtype: *mut ffi::PyTypeObject,
-    _args: *mut ffi::PyObject,
-    _kwds: *mut ffi::PyObject,
-) -> *mut ffi::PyObject {
-    crate::callback_body!(py, {
-        Err::<(), _>(crate::exceptions::PyTypeError::new_err(
-            "No constructor defined",
-        ))
-    })
-}
-
-/// Implementation of tp_dealloc for all pyclasses
-pub(crate) unsafe extern "C" fn tp_dealloc<T: PyClass>(obj: *mut ffi::PyObject) {
-    crate::callback_body!(py, T::Layout::tp_dealloc(obj, py))
-}
-
-pub(crate) unsafe extern "C" fn get_sequence_item_from_mapping(
-    obj: *mut ffi::PyObject,
-    index: ffi::Py_ssize_t,
-) -> *mut ffi::PyObject {
-    let index = ffi::PyLong_FromSsize_t(index);
-    if index.is_null() {
-        return std::ptr::null_mut();
-    }
-    let result = ffi::PyObject_GetItem(obj, index);
-    ffi::Py_DECREF(index);
-    result
-}
-
-pub(crate) unsafe extern "C" fn assign_sequence_item_from_mapping(
-    obj: *mut ffi::PyObject,
-    index: ffi::Py_ssize_t,
-    value: *mut ffi::PyObject,
-) -> c_int {
-    let index = ffi::PyLong_FromSsize_t(index);
-    if index.is_null() {
-        return -1;
-    }
-    let result = if value.is_null() {
-        ffi::PyObject_DelItem(obj, index)
-    } else {
-        ffi::PyObject_SetItem(obj, index, value)
-    };
-    ffi::Py_DECREF(index);
-    result
-}
diff --git a/src/class/iter.rs b/src/class/iter.rs
index 2ac29a9d..3d980375 100644
--- a/src/class/iter.rs
+++ b/src/class/iter.rs
@@ -4,8 +4,7 @@
 
 use crate::callback::IntoPyCallbackOutput;
 use crate::derive_utils::TryFromPyCell;
-use crate::err::PyResult;
-use crate::{ffi, IntoPy, IntoPyPointer, PyClass, PyObject, Python};
+use crate::{PyClass, PyObject};
 
 /// Python Iterator Interface.
 ///
@@ -73,49 +72,4 @@ pub trait PyIterNextProtocol<'p>: PyIterProtocol<'p> {
 py_unarys_func!(iter, PyIterIterProtocol, Self::__iter__);
 py_unarys_func!(iternext, PyIterNextProtocol, Self::__next__);
 
-/// Output of `__next__` which can either `yield` the next value in the iteration, or
-/// `return` a value to raise `StopIteration` in Python.
-///
-/// See [`PyIterProtocol`](trait.PyIterProtocol.html) for an example.
-pub enum IterNextOutput<T, U> {
-    /// The value yielded by the iterator.
-    Yield(T),
-    /// The `StopIteration` object.
-    Return(U),
-}
-
-pub type PyIterNextOutput = IterNextOutput<PyObject, PyObject>;
-
-impl IntoPyCallbackOutput<*mut ffi::PyObject> for PyIterNextOutput {
-    fn convert(self, _py: Python) -> PyResult<*mut ffi::PyObject> {
-        match self {
-            IterNextOutput::Yield(o) => Ok(o.into_ptr()),
-            IterNextOutput::Return(opt) => Err(crate::exceptions::PyStopIteration::new_err((opt,))),
-        }
-    }
-}
-
-impl<T, U> IntoPyCallbackOutput<PyIterNextOutput> for IterNextOutput<T, U>
-where
-    T: IntoPy<PyObject>,
-    U: IntoPy<PyObject>,
-{
-    fn convert(self, py: Python) -> PyResult<PyIterNextOutput> {
-        match self {
-            IterNextOutput::Yield(o) => Ok(IterNextOutput::Yield(o.into_py(py))),
-            IterNextOutput::Return(o) => Ok(IterNextOutput::Return(o.into_py(py))),
-        }
-    }
-}
-
-impl<T> IntoPyCallbackOutput<PyIterNextOutput> for Option<T>
-where
-    T: IntoPy<PyObject>,
-{
-    fn convert(self, py: Python) -> PyResult<PyIterNextOutput> {
-        match self {
-            Some(o) => Ok(PyIterNextOutput::Yield(o.into_py(py))),
-            None => Ok(PyIterNextOutput::Return(py.None())),
-        }
-    }
-}
+pub use crate::pyclass::{IterNextOutput, PyIterNextOutput};
diff --git a/src/class/methods.rs b/src/class/methods.rs
index 5f537e3a..e69de29b 100644
--- a/src/class/methods.rs
+++ b/src/class/methods.rs
@@ -1,220 +0,0 @@
-// Copyright (c) 2017-present PyO3 Project and Contributors
-
-use crate::internal_tricks::{extract_cstr_or_leak_cstring, NulByteInString};
-use crate::{ffi, PyObject, Python};
-use std::ffi::CStr;
-use std::fmt;
-use std::os::raw::c_int;
-
-/// `PyMethodDefType` represents different types of Python callable objects.
-/// It is used by the `#[pymethods]` and `#[pyproto]` annotations.
-#[derive(Debug)]
-pub enum PyMethodDefType {
-    /// Represents class method
-    Class(PyMethodDef),
-    /// Represents static method
-    Static(PyMethodDef),
-    /// Represents normal method
-    Method(PyMethodDef),
-    /// Represents class attribute, used by `#[attribute]`
-    ClassAttribute(PyClassAttributeDef),
-    /// Represents getter descriptor, used by `#[getter]`
-    Getter(PyGetterDef),
-    /// Represents setter descriptor, used by `#[setter]`
-    Setter(PySetterDef),
-}
-
-#[derive(Copy, Clone, Debug)]
-pub enum PyMethodType {
-    PyCFunction(PyCFunction),
-    PyCFunctionWithKeywords(PyCFunctionWithKeywords),
-    #[cfg(not(Py_LIMITED_API))]
-    PyCFunctionFastWithKeywords(PyCFunctionFastWithKeywords),
-}
-
-// These newtype structs serve no purpose other than wrapping which are function pointers - because
-// function pointers aren't allowed in const fn, but types wrapping them are!
-#[derive(Clone, Copy, Debug)]
-pub struct PyCFunction(pub ffi::PyCFunction);
-#[derive(Clone, Copy, Debug)]
-pub struct PyCFunctionWithKeywords(pub ffi::PyCFunctionWithKeywords);
-#[cfg(not(Py_LIMITED_API))]
-#[derive(Clone, Copy, Debug)]
-pub struct PyCFunctionFastWithKeywords(pub ffi::_PyCFunctionFastWithKeywords);
-#[derive(Clone, Copy, Debug)]
-pub struct PyGetter(pub ffi::getter);
-#[derive(Clone, Copy, Debug)]
-pub struct PySetter(pub ffi::setter);
-#[derive(Clone, Copy)]
-pub struct PyClassAttributeFactory(pub for<'p> fn(Python<'p>) -> PyObject);
-
-// TODO: it would be nice to use CStr in these types, but then the constructors can't be const fn
-// until `CStr::from_bytes_with_nul_unchecked` is const fn.
-
-#[derive(Clone, Debug)]
-pub struct PyMethodDef {
-    pub(crate) ml_name: &'static str,
-    pub(crate) ml_meth: PyMethodType,
-    pub(crate) ml_flags: c_int,
-    pub(crate) ml_doc: &'static str,
-}
-
-#[derive(Copy, Clone)]
-pub struct PyClassAttributeDef {
-    pub(crate) name: &'static str,
-    pub(crate) meth: PyClassAttributeFactory,
-}
-
-#[derive(Clone, Debug)]
-pub struct PyGetterDef {
-    pub(crate) name: &'static str,
-    pub(crate) meth: PyGetter,
-    doc: &'static str,
-}
-
-#[derive(Clone, Debug)]
-pub struct PySetterDef {
-    pub(crate) name: &'static str,
-    pub(crate) meth: PySetter,
-    doc: &'static str,
-}
-
-unsafe impl Sync for PyMethodDef {}
-
-unsafe impl Sync for PyGetterDef {}
-
-unsafe impl Sync for PySetterDef {}
-
-impl PyMethodDef {
-    /// Define a function with no `*args` and `**kwargs`.
-    pub const fn noargs(name: &'static str, cfunction: PyCFunction, doc: &'static str) -> Self {
-        Self {
-            ml_name: name,
-            ml_meth: PyMethodType::PyCFunction(cfunction),
-            ml_flags: ffi::METH_NOARGS,
-            ml_doc: doc,
-        }
-    }
-
-    /// Define a function that can take `*args` and `**kwargs`.
-    pub const fn cfunction_with_keywords(
-        name: &'static str,
-        cfunction: PyCFunctionWithKeywords,
-        doc: &'static str,
-    ) -> Self {
-        Self {
-            ml_name: name,
-            ml_meth: PyMethodType::PyCFunctionWithKeywords(cfunction),
-            ml_flags: ffi::METH_VARARGS | ffi::METH_KEYWORDS,
-            ml_doc: doc,
-        }
-    }
-
-    /// Define a function that can take `*args` and `**kwargs`.
-    #[cfg(not(Py_LIMITED_API))]
-    pub const fn fastcall_cfunction_with_keywords(
-        name: &'static str,
-        cfunction: PyCFunctionFastWithKeywords,
-        doc: &'static str,
-    ) -> Self {
-        Self {
-            ml_name: name,
-            ml_meth: PyMethodType::PyCFunctionFastWithKeywords(cfunction),
-            ml_flags: ffi::METH_FASTCALL | ffi::METH_KEYWORDS,
-            ml_doc: doc,
-        }
-    }
-
-    pub const fn flags(mut self, flags: c_int) -> Self {
-        self.ml_flags |= flags;
-        self
-    }
-
-    /// Convert `PyMethodDef` to Python method definition struct `ffi::PyMethodDef`
-    pub(crate) fn as_method_def(&self) -> Result<ffi::PyMethodDef, NulByteInString> {
-        let meth = match self.ml_meth {
-            PyMethodType::PyCFunction(meth) => meth.0,
-            PyMethodType::PyCFunctionWithKeywords(meth) => unsafe { std::mem::transmute(meth.0) },
-            #[cfg(not(Py_LIMITED_API))]
-            PyMethodType::PyCFunctionFastWithKeywords(meth) => unsafe {
-                std::mem::transmute(meth.0)
-            },
-        };
-
-        Ok(ffi::PyMethodDef {
-            ml_name: get_name(self.ml_name)?.as_ptr(),
-            ml_meth: Some(meth),
-            ml_flags: self.ml_flags,
-            ml_doc: get_doc(self.ml_doc)?.as_ptr(),
-        })
-    }
-}
-
-impl PyClassAttributeDef {
-    /// Define a class attribute.
-    pub const fn new(name: &'static str, meth: PyClassAttributeFactory) -> Self {
-        Self { name, meth }
-    }
-}
-
-// Manual implementation because `Python<'_>` does not implement `Debug` and
-// trait bounds on `fn` compiler-generated derive impls are too restrictive.
-impl fmt::Debug for PyClassAttributeDef {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("PyClassAttributeDef")
-            .field("name", &self.name)
-            .finish()
-    }
-}
-
-impl PyGetterDef {
-    /// Define a getter.
-    pub const fn new(name: &'static str, getter: PyGetter, doc: &'static str) -> Self {
-        Self {
-            name,
-            meth: getter,
-            doc,
-        }
-    }
-
-    /// Copy descriptor information to `ffi::PyGetSetDef`
-    pub fn copy_to(&self, dst: &mut ffi::PyGetSetDef) {
-        if dst.name.is_null() {
-            dst.name = get_name(self.name).unwrap().as_ptr() as _;
-        }
-        if dst.doc.is_null() {
-            dst.doc = get_doc(self.doc).unwrap().as_ptr() as _;
-        }
-        dst.get = Some(self.meth.0);
-    }
-}
-
-impl PySetterDef {
-    /// Define a setter.
-    pub const fn new(name: &'static str, setter: PySetter, doc: &'static str) -> Self {
-        Self {
-            name,
-            meth: setter,
-            doc,
-        }
-    }
-
-    /// Copy descriptor information to `ffi::PyGetSetDef`
-    pub fn copy_to(&self, dst: &mut ffi::PyGetSetDef) {
-        if dst.name.is_null() {
-            dst.name = get_name(self.name).unwrap().as_ptr() as _;
-        }
-        if dst.doc.is_null() {
-            dst.doc = get_doc(self.doc).unwrap().as_ptr() as _;
-        }
-        dst.set = Some(self.meth.0);
-    }
-}
-
-fn get_name(name: &'static str) -> Result<&'static CStr, NulByteInString> {
-    extract_cstr_or_leak_cstring(name, "Function name cannot contain NUL byte.")
-}
-
-fn get_doc(doc: &'static str) -> Result<&'static CStr, NulByteInString> {
-    extract_cstr_or_leak_cstring(doc, "Document cannot contain NUL byte.")
-}
diff --git a/src/class/mod.rs b/src/class/mod.rs
index 0e889573..3220ad3a 100644
--- a/src/class/mod.rs
+++ b/src/class/mod.rs
@@ -10,12 +10,10 @@ pub mod basic;
 pub mod buffer;
 pub mod descr;
 pub mod gc;
-#[doc(hidden)]
-pub mod impl_;
 pub mod iter;
 pub mod mapping;
 #[doc(hidden)]
-pub mod methods;
+pub use crate::impl_::pymethods as methods;
 pub mod number;
 pub mod pyasync;
 pub mod sequence;
diff --git a/src/class/pyasync.rs b/src/class/pyasync.rs
index f79cd7ac..96053824 100644
--- a/src/class/pyasync.rs
+++ b/src/class/pyasync.rs
@@ -9,8 +9,7 @@
 
 use crate::callback::IntoPyCallbackOutput;
 use crate::derive_utils::TryFromPyCell;
-use crate::err::PyResult;
-use crate::{ffi, IntoPy, IntoPyPointer, PyClass, PyObject, Python};
+use crate::{PyClass, PyObject};
 
 /// Python Async/Await support interface.
 ///
@@ -58,51 +57,4 @@ py_unarys_func!(await_, PyAsyncAwaitProtocol, Self::__await__);
 py_unarys_func!(aiter, PyAsyncAiterProtocol, Self::__aiter__);
 py_unarys_func!(anext, PyAsyncAnextProtocol, Self::__anext__);
 
-/// Output of `__anext__`.
-///
-/// <https://docs.python.org/3/reference/expressions.html#agen.__anext__>
-pub enum IterANextOutput<T, U> {
-    /// An expression which the generator yielded.
-    Yield(T),
-    /// A `StopAsyncIteration` object.
-    Return(U),
-}
-
-/// An [IterANextOutput] of Python objects.
-pub type PyIterANextOutput = IterANextOutput<PyObject, PyObject>;
-
-impl IntoPyCallbackOutput<*mut ffi::PyObject> for PyIterANextOutput {
-    fn convert(self, _py: Python) -> PyResult<*mut ffi::PyObject> {
-        match self {
-            IterANextOutput::Yield(o) => Ok(o.into_ptr()),
-            IterANextOutput::Return(opt) => {
-                Err(crate::exceptions::PyStopAsyncIteration::new_err((opt,)))
-            }
-        }
-    }
-}
-
-impl<T, U> IntoPyCallbackOutput<PyIterANextOutput> for IterANextOutput<T, U>
-where
-    T: IntoPy<PyObject>,
-    U: IntoPy<PyObject>,
-{
-    fn convert(self, py: Python) -> PyResult<PyIterANextOutput> {
-        match self {
-            IterANextOutput::Yield(o) => Ok(IterANextOutput::Yield(o.into_py(py))),
-            IterANextOutput::Return(o) => Ok(IterANextOutput::Return(o.into_py(py))),
-        }
-    }
-}
-
-impl<T> IntoPyCallbackOutput<PyIterANextOutput> for Option<T>
-where
-    T: IntoPy<PyObject>,
-{
-    fn convert(self, py: Python) -> PyResult<PyIterANextOutput> {
-        match self {
-            Some(o) => Ok(PyIterANextOutput::Yield(o.into_py(py))),
-            None => Ok(PyIterANextOutput::Return(py.None())),
-        }
-    }
-}
+pub use crate::pyclass::{IterANextOutput, PyIterANextOutput};
diff --git a/src/impl_/pyclass.rs b/src/impl_/pyclass.rs
index ae534611..66ac7c83 100644
--- a/src/impl_/pyclass.rs
+++ b/src/impl_/pyclass.rs
@@ -1,4 +1,13 @@
-use crate::{ffi, PyCell, PyClass, Python};
+use crate::{
+    exceptions::{PyAttributeError, PyNotImplementedError},
+    ffi,
+    impl_::freelist::FreeList,
+    pycell::PyCellLayout,
+    pyclass_init::PyObjectInit,
+    type_object::{PyLayout, PyTypeObject},
+    PyCell, PyClass, PyMethodDefType, PyNativeType, PyResult, PyTypeInfo, Python,
+};
+use std::{marker::PhantomData, os::raw::{c_int, c_void}, ptr::NonNull, thread};
 
 /// Gets the offset of the dictionary from the start of the object in bytes.
 #[inline]
@@ -94,3 +103,804 @@ impl PyClassWeakRef for PyClassWeakRefSlot {
         }
     }
 }
+
+/// This type is used as a "dummy" type on which dtolnay specializations are
+/// applied to apply implementations from `#[pymethods]` & `#[pyproto]`
+pub struct PyClassImplCollector<T>(PhantomData<T>);
+
+impl<T> PyClassImplCollector<T> {
+    pub fn new() -> Self {
+        Self(PhantomData)
+    }
+}
+
+impl<T> Default for PyClassImplCollector<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T> Clone for PyClassImplCollector<T> {
+    fn clone(&self) -> Self {
+        Self::new()
+    }
+}
+
+impl<T> Copy for PyClassImplCollector<T> {}
+
+/// Implements the underlying functionality of `#[pyclass]`, assembled by various proc macros.
+///
+/// Users are discouraged from implementing this trait manually; it is a PyO3 implementation detail
+/// and may be changed at any time.
+pub trait PyClassImpl: Sized {
+    /// Class doc string
+    const DOC: &'static str = "\0";
+
+    /// #[pyclass(gc)]
+    const IS_GC: bool = false;
+
+    /// #[pyclass(subclass)]
+    const IS_BASETYPE: bool = false;
+
+    /// #[pyclass(extends=...)]
+    const IS_SUBCLASS: bool = false;
+
+    /// Layout
+    type Layout: PyLayout<Self>;
+
+    /// Base class
+    type BaseType: PyTypeInfo + PyTypeObject + PyClassBaseType;
+
+    /// This handles following two situations:
+    /// 1. In case `T` is `Send`, stub `ThreadChecker` is used and does nothing.
+    ///    This implementation is used by default. Compile fails if `T: !Send`.
+    /// 2. In case `T` is `!Send`, `ThreadChecker` panics when `T` is accessed by another thread.
+    ///    This implementation is used when `#[pyclass(unsendable)]` is given.
+    ///    Panicking makes it safe to expose `T: !Send` to the Python interpreter, where all objects
+    ///    can be accessed by multiple threads by `threading` module.
+    type ThreadChecker: PyClassThreadChecker<Self>;
+
+    #[cfg(feature = "multiple-pymethods")]
+    type Inventory: PyClassInventory;
+
+    fn for_each_method_def(_visitor: &mut dyn FnMut(&[PyMethodDefType])) {}
+    fn for_each_proto_slot(_visitor: &mut dyn FnMut(&[ffi::PyType_Slot])) {}
+
+    #[inline]
+    fn get_new() -> Option<ffi::newfunc> {
+        None
+    }
+    #[inline]
+    fn get_alloc() -> Option<ffi::allocfunc> {
+        None
+    }
+    #[inline]
+    fn get_free() -> Option<ffi::freefunc> {
+        None
+    }
+    #[inline]
+    fn dict_offset() -> Option<ffi::Py_ssize_t> {
+        None
+    }
+    #[inline]
+    fn weaklist_offset() -> Option<ffi::Py_ssize_t> {
+        None
+    }
+}
+
+// Traits describing known special methods.
+
+pub trait PyClassNewImpl<T> {
+    fn new_impl(self) -> Option<ffi::newfunc>;
+}
+
+impl<T> PyClassNewImpl<T> for &'_ PyClassImplCollector<T> {
+    fn new_impl(self) -> Option<ffi::newfunc> {
+        None
+    }
+}
+
+macro_rules! slot_fragment_trait {
+    ($trait_name:ident, $($default_method:tt)*) => {
+        #[allow(non_camel_case_types)]
+        pub trait $trait_name<T>: Sized {
+            $($default_method)*
+        }
+
+        impl<T> $trait_name<T> for &'_ PyClassImplCollector<T> {}
+    }
+}
+
+/// Macro which expands to three items
+/// - Trait for a __setitem__ dunder
+/// - Trait for the corresponding __delitem__ dunder
+/// - A macro which will use dtolnay specialisation to generate the shared slot for the two dunders
+macro_rules! define_pyclass_setattr_slot {
+    (
+        $set_trait:ident,
+        $del_trait:ident,
+        $set:ident,
+        $del:ident,
+        $set_error:expr,
+        $del_error:expr,
+        $generate_macro:ident,
+        $slot:ident,
+        $func_ty:ident,
+    ) => {
+        slot_fragment_trait! {
+            $set_trait,
+
+            /// # Safety: _slf and _attr must be valid non-null Python objects
+            #[inline]
+            unsafe fn $set(
+                self,
+                _py: Python,
+                _slf: *mut ffi::PyObject,
+                _attr: *mut ffi::PyObject,
+                _value: NonNull<ffi::PyObject>,
+            ) -> PyResult<()> {
+                $set_error
+            }
+        }
+
+        slot_fragment_trait! {
+            $del_trait,
+
+            /// # Safety: _slf and _attr must be valid non-null Python objects
+            #[inline]
+            unsafe fn $del(
+                self,
+                _py: Python,
+                _slf: *mut ffi::PyObject,
+                _attr: *mut ffi::PyObject,
+            ) -> PyResult<()> {
+                $del_error
+            }
+        }
+
+        #[doc(hidden)]
+        #[macro_export]
+        macro_rules! $generate_macro {
+            ($cls:ty) => {{
+                unsafe extern "C" fn __wrap(
+                    _slf: *mut $crate::ffi::PyObject,
+                    attr: *mut $crate::ffi::PyObject,
+                    value: *mut $crate::ffi::PyObject,
+                ) -> ::std::os::raw::c_int {
+                    use ::std::option::Option::*;
+                    use $crate::callback::IntoPyCallbackOutput;
+                    use $crate::impl_::pyclass::*;
+                    $crate::callback::handle_panic(|py| {
+                        let collector = PyClassImplCollector::<$cls>::new();
+                        if let Some(value) = ::std::ptr::NonNull::new(value) {
+                            collector.$set(py, _slf, attr, value).convert(py)
+                        } else {
+                            collector.$del(py, _slf, attr).convert(py)
+                        }
+                    })
+                }
+                $crate::ffi::PyType_Slot {
+                    slot: $crate::ffi::$slot,
+                    pfunc: __wrap as $crate::ffi::$func_ty as _,
+                }
+            }};
+        }
+        pub use $generate_macro;
+    };
+}
+
+define_pyclass_setattr_slot! {
+    PyClass__setattr__SlotFragment,
+    PyClass__delattr__SlotFragment,
+    __setattr__,
+    __delattr__,
+    Err(PyAttributeError::new_err("can't set attribute")),
+    Err(PyAttributeError::new_err("can't delete attribute")),
+    generate_pyclass_setattr_slot,
+    Py_tp_setattro,
+    setattrofunc,
+}
+
+define_pyclass_setattr_slot! {
+    PyClass__set__SlotFragment,
+    PyClass__delete__SlotFragment,
+    __set__,
+    __delete__,
+    Err(PyNotImplementedError::new_err("can't set descriptor")),
+    Err(PyNotImplementedError::new_err("can't delete descriptor")),
+    generate_pyclass_setdescr_slot,
+    Py_tp_descr_set,
+    descrsetfunc,
+}
+
+define_pyclass_setattr_slot! {
+    PyClass__setitem__SlotFragment,
+    PyClass__delitem__SlotFragment,
+    __setitem__,
+    __delitem__,
+    Err(PyNotImplementedError::new_err("can't set item")),
+    Err(PyNotImplementedError::new_err("can't delete item")),
+    generate_pyclass_setitem_slot,
+    Py_mp_ass_subscript,
+    objobjargproc,
+}
+
+/// Macro which expands to three items
+/// - Trait for a lhs dunder e.g. __add__
+/// - Trait for the corresponding rhs e.g. __radd__
+/// - A macro which will use dtolnay specialisation to generate the shared slot for the two dunders
+macro_rules! define_pyclass_binary_operator_slot {
+    (
+        $lhs_trait:ident,
+        $rhs_trait:ident,
+        $lhs:ident,
+        $rhs:ident,
+        $generate_macro:ident,
+        $slot:ident,
+        $func_ty:ident,
+    ) => {
+        slot_fragment_trait! {
+            $lhs_trait,
+
+            /// # Safety: _slf and _other must be valid non-null Python objects
+            #[inline]
+            unsafe fn $lhs(
+                self,
+                _py: Python,
+                _slf: *mut ffi::PyObject,
+                _other: *mut ffi::PyObject,
+            ) -> PyResult<*mut ffi::PyObject> {
+                Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
+            }
+        }
+
+        slot_fragment_trait! {
+            $rhs_trait,
+
+            /// # Safety: _slf and _other must be valid non-null Python objects
+            #[inline]
+            unsafe fn $rhs(
+                self,
+                _py: Python,
+                _slf: *mut ffi::PyObject,
+                _other: *mut ffi::PyObject,
+            ) -> PyResult<*mut ffi::PyObject> {
+                Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
+            }
+        }
+
+        #[doc(hidden)]
+        #[macro_export]
+        macro_rules! $generate_macro {
+            ($cls:ty) => {{
+                unsafe extern "C" fn __wrap(
+                    _slf: *mut $crate::ffi::PyObject,
+                    _other: *mut $crate::ffi::PyObject,
+                ) -> *mut $crate::ffi::PyObject {
+                    $crate::callback::handle_panic(|py| {
+                        use $crate::impl_::pyclass::*;
+                        let collector = PyClassImplCollector::<$cls>::new();
+                        let lhs_result = collector.$lhs(py, _slf, _other)?;
+                        if lhs_result == $crate::ffi::Py_NotImplemented() {
+                            $crate::ffi::Py_DECREF(lhs_result);
+                            collector.$rhs(py, _other, _slf)
+                        } else {
+                            ::std::result::Result::Ok(lhs_result)
+                        }
+                    })
+                }
+                $crate::ffi::PyType_Slot {
+                    slot: $crate::ffi::$slot,
+                    pfunc: __wrap as $crate::ffi::$func_ty as _,
+                }
+            }};
+        }
+        pub use $generate_macro;
+    };
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__add__SlotFragment,
+    PyClass__radd__SlotFragment,
+    __add__,
+    __radd__,
+    generate_pyclass_add_slot,
+    Py_nb_add,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__sub__SlotFragment,
+    PyClass__rsub__SlotFragment,
+    __sub__,
+    __rsub__,
+    generate_pyclass_sub_slot,
+    Py_nb_subtract,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__mul__SlotFragment,
+    PyClass__rmul__SlotFragment,
+    __mul__,
+    __rmul__,
+    generate_pyclass_mul_slot,
+    Py_nb_multiply,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__mod__SlotFragment,
+    PyClass__rmod__SlotFragment,
+    __mod__,
+    __rmod__,
+    generate_pyclass_mod_slot,
+    Py_nb_remainder,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__divmod__SlotFragment,
+    PyClass__rdivmod__SlotFragment,
+    __divmod__,
+    __rdivmod__,
+    generate_pyclass_divmod_slot,
+    Py_nb_divmod,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__lshift__SlotFragment,
+    PyClass__rlshift__SlotFragment,
+    __lshift__,
+    __rlshift__,
+    generate_pyclass_lshift_slot,
+    Py_nb_lshift,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__rshift__SlotFragment,
+    PyClass__rrshift__SlotFragment,
+    __rshift__,
+    __rrshift__,
+    generate_pyclass_rshift_slot,
+    Py_nb_rshift,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__and__SlotFragment,
+    PyClass__rand__SlotFragment,
+    __and__,
+    __rand__,
+    generate_pyclass_and_slot,
+    Py_nb_and,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__or__SlotFragment,
+    PyClass__ror__SlotFragment,
+    __or__,
+    __ror__,
+    generate_pyclass_or_slot,
+    Py_nb_or,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__xor__SlotFragment,
+    PyClass__rxor__SlotFragment,
+    __xor__,
+    __rxor__,
+    generate_pyclass_xor_slot,
+    Py_nb_xor,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__matmul__SlotFragment,
+    PyClass__rmatmul__SlotFragment,
+    __matmul__,
+    __rmatmul__,
+    generate_pyclass_matmul_slot,
+    Py_nb_matrix_multiply,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__truediv__SlotFragment,
+    PyClass__rtruediv__SlotFragment,
+    __truediv__,
+    __rtruediv__,
+    generate_pyclass_truediv_slot,
+    Py_nb_true_divide,
+    binaryfunc,
+}
+
+define_pyclass_binary_operator_slot! {
+    PyClass__floordiv__SlotFragment,
+    PyClass__rfloordiv__SlotFragment,
+    __floordiv__,
+    __rfloordiv__,
+    generate_pyclass_floordiv_slot,
+    Py_nb_floor_divide,
+    binaryfunc,
+}
+
+slot_fragment_trait! {
+    PyClass__pow__SlotFragment,
+
+    /// # Safety: _slf and _other must be valid non-null Python objects
+    #[inline]
+    unsafe fn __pow__(
+        self,
+        _py: Python,
+        _slf: *mut ffi::PyObject,
+        _other: *mut ffi::PyObject,
+        _mod: *mut ffi::PyObject,
+    ) -> PyResult<*mut ffi::PyObject> {
+        Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
+    }
+}
+
+slot_fragment_trait! {
+    PyClass__rpow__SlotFragment,
+
+    /// # Safety: _slf and _other must be valid non-null Python objects
+    #[inline]
+    unsafe fn __rpow__(
+        self,
+        _py: Python,
+        _slf: *mut ffi::PyObject,
+        _other: *mut ffi::PyObject,
+        _mod: *mut ffi::PyObject,
+    ) -> PyResult<*mut ffi::PyObject> {
+        Ok(ffi::_Py_NewRef(ffi::Py_NotImplemented()))
+    }
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! generate_pyclass_pow_slot {
+    ($cls:ty) => {{
+        unsafe extern "C" fn __wrap(
+            _slf: *mut $crate::ffi::PyObject,
+            _other: *mut $crate::ffi::PyObject,
+            _mod: *mut $crate::ffi::PyObject,
+        ) -> *mut $crate::ffi::PyObject {
+            $crate::callback::handle_panic(|py| {
+                use $crate::impl_::pyclass::*;
+                let collector = PyClassImplCollector::<$cls>::new();
+                let lhs_result = collector.__pow__(py, _slf, _other, _mod)?;
+                if lhs_result == $crate::ffi::Py_NotImplemented() {
+                    $crate::ffi::Py_DECREF(lhs_result);
+                    collector.__rpow__(py, _other, _slf, _mod)
+                } else {
+                    ::std::result::Result::Ok(lhs_result)
+                }
+            })
+        }
+        $crate::ffi::PyType_Slot {
+            slot: $crate::ffi::Py_nb_power,
+            pfunc: __wrap as $crate::ffi::ternaryfunc as _,
+        }
+    }};
+}
+pub use generate_pyclass_pow_slot;
+
+pub trait PyClassAllocImpl<T> {
+    fn alloc_impl(self) -> Option<ffi::allocfunc>;
+}
+
+impl<T> PyClassAllocImpl<T> for &'_ PyClassImplCollector<T> {
+    fn alloc_impl(self) -> Option<ffi::allocfunc> {
+        None
+    }
+}
+
+pub trait PyClassFreeImpl<T> {
+    fn free_impl(self) -> Option<ffi::freefunc>;
+}
+
+impl<T> PyClassFreeImpl<T> for &'_ PyClassImplCollector<T> {
+    fn free_impl(self) -> Option<ffi::freefunc> {
+        None
+    }
+}
+
+/// Implements a freelist.
+///
+/// Do not implement this trait manually. Instead, use `#[pyclass(freelist = N)]`
+/// on a Rust struct to implement it.
+pub trait PyClassWithFreeList: PyClass {
+    fn get_free_list(py: Python) -> &mut FreeList<*mut ffi::PyObject>;
+}
+
+/// Implementation of tp_alloc for `freelist` classes.
+///
+/// # Safety
+/// - `subtype` must be a valid pointer to the type object of T or a subclass.
+/// - The GIL must be held.
+pub unsafe extern "C" fn alloc_with_freelist<T: PyClassWithFreeList>(
+    subtype: *mut ffi::PyTypeObject,
+    nitems: ffi::Py_ssize_t,
+) -> *mut ffi::PyObject {
+    let py = Python::assume_gil_acquired();
+
+    #[cfg(not(Py_3_8))]
+    bpo_35810_workaround(py, subtype);
+
+    let self_type = T::type_object_raw(py);
+    // If this type is a variable type or the subtype is not equal to this type, we cannot use the
+    // freelist
+    if nitems == 0 && subtype == self_type {
+        if let Some(obj) = T::get_free_list(py).pop() {
+            ffi::PyObject_Init(obj, subtype);
+            return obj as _;
+        }
+    }
+
+    ffi::PyType_GenericAlloc(subtype, nitems)
+}
+
+/// Implementation of tp_free for `freelist` classes.
+///
+/// # Safety
+/// - `obj` must be a valid pointer to an instance of T (not a subclass).
+/// - The GIL must be held.
+pub unsafe extern "C" fn free_with_freelist<T: PyClassWithFreeList>(obj: *mut c_void) {
+    let obj = obj as *mut ffi::PyObject;
+    debug_assert_eq!(
+        T::type_object_raw(Python::assume_gil_acquired()),
+        ffi::Py_TYPE(obj)
+    );
+    if let Some(obj) = T::get_free_list(Python::assume_gil_acquired()).insert(obj) {
+        let ty = ffi::Py_TYPE(obj);
+
+        // Deduce appropriate inverse of PyType_GenericAlloc
+        let free = if ffi::PyType_IS_GC(ty) != 0 {
+            ffi::PyObject_GC_Del
+        } else {
+            ffi::PyObject_Free
+        };
+        free(obj as *mut c_void);
+
+        #[cfg(Py_3_8)]
+        if ffi::PyType_HasFeature(ty, ffi::Py_TPFLAGS_HEAPTYPE) != 0 {
+            ffi::Py_DECREF(ty as *mut ffi::PyObject);
+        }
+    }
+}
+
+/// Workaround for Python issue 35810; no longer necessary in Python 3.8
+#[inline]
+#[cfg(not(Py_3_8))]
+unsafe fn bpo_35810_workaround(_py: Python, ty: *mut ffi::PyTypeObject) {
+    #[cfg(Py_LIMITED_API)]
+    {
+        // Must check version at runtime for abi3 wheels - they could run against a higher version
+        // than the build config suggests.
+        use crate::once_cell::GILOnceCell;
+        static IS_PYTHON_3_8: GILOnceCell<bool> = GILOnceCell::new();
+
+        if *IS_PYTHON_3_8.get_or_init(_py, || _py.version_info() >= (3, 8)) {
+            // No fix needed - the wheel is running on a sufficiently new interpreter.
+            return;
+        }
+    }
+
+    ffi::Py_INCREF(ty as *mut ffi::PyObject);
+}
+
+// General methods implementation: either dtolnay specialization trait or inventory if
+// multiple-pymethods feature is enabled.
+
+macro_rules! methods_trait {
+    ($name:ident, $function_name: ident) => {
+        pub trait $name<T> {
+            fn $function_name(self) -> &'static [PyMethodDefType];
+        }
+
+        impl<T> $name<T> for &'_ PyClassImplCollector<T> {
+            fn $function_name(self) -> &'static [PyMethodDefType] {
+                &[]
+            }
+        }
+    };
+}
+
+/// Implementation detail. Only to be used through our proc macro code.
+/// Method storage for `#[pyclass]`.
+/// Allows arbitrary `#[pymethod]` blocks to submit their methods,
+/// which are eventually collected by `#[pyclass]`.
+#[cfg(feature = "multiple-pymethods")]
+pub trait PyClassInventory: inventory::Collect {
+    /// Returns the methods for a single `#[pymethods] impl` block
+    fn methods(&'static self) -> &'static [PyMethodDefType];
+
+    /// Returns the slots for a single `#[pymethods] impl` block
+    fn slots(&'static self) -> &'static [ffi::PyType_Slot];
+}
+
+// Methods from #[pyo3(get, set)] on struct fields.
+methods_trait!(PyClassDescriptors, py_class_descriptors);
+
+// Methods from #[pymethods] if not using inventory.
+#[cfg(not(feature = "multiple-pymethods"))]
+methods_trait!(PyMethods, py_methods);
+
+// All traits describing slots, as well as the fallback implementations for unimplemented protos
+//
+// Protos which are implemented use dtolnay specialization to implement for PyClassImplCollector<T>.
+//
+// See https://github.com/dtolnay/case-studies/blob/master/autoref-specialization/README.md
+
+macro_rules! slots_trait {
+    ($name:ident, $function_name: ident) => {
+        pub trait $name<T> {
+            fn $function_name(self) -> &'static [ffi::PyType_Slot];
+        }
+
+        impl<T> $name<T> for &'_ PyClassImplCollector<T> {
+            fn $function_name(self) -> &'static [ffi::PyType_Slot] {
+                &[]
+            }
+        }
+    };
+}
+
+slots_trait!(PyObjectProtocolSlots, object_protocol_slots);
+slots_trait!(PyDescrProtocolSlots, descr_protocol_slots);
+slots_trait!(PyGCProtocolSlots, gc_protocol_slots);
+slots_trait!(PyIterProtocolSlots, iter_protocol_slots);
+slots_trait!(PyMappingProtocolSlots, mapping_protocol_slots);
+slots_trait!(PyNumberProtocolSlots, number_protocol_slots);
+slots_trait!(PyAsyncProtocolSlots, async_protocol_slots);
+slots_trait!(PySequenceProtocolSlots, sequence_protocol_slots);
+slots_trait!(PyBufferProtocolSlots, buffer_protocol_slots);
+
+// slots that PyO3 implements by default, but can be overidden by the users.
+slots_trait!(PyClassDefaultSlots, py_class_default_slots);
+
+// Protocol slots from #[pymethods] if not using inventory.
+#[cfg(not(feature = "multiple-pymethods"))]
+slots_trait!(PyMethodsProtocolSlots, methods_protocol_slots);
+
+methods_trait!(PyObjectProtocolMethods, object_protocol_methods);
+methods_trait!(PyAsyncProtocolMethods, async_protocol_methods);
+methods_trait!(PyDescrProtocolMethods, descr_protocol_methods);
+methods_trait!(PyMappingProtocolMethods, mapping_protocol_methods);
+methods_trait!(PyNumberProtocolMethods, number_protocol_methods);
+
+// Thread checkers
+
+#[doc(hidden)]
+pub trait PyClassThreadChecker<T>: Sized {
+    fn ensure(&self);
+    fn new() -> Self;
+    private_decl! {}
+}
+
+/// Stub checker for `Send` types.
+#[doc(hidden)]
+pub struct ThreadCheckerStub<T: Send>(PhantomData<T>);
+
+impl<T: Send> PyClassThreadChecker<T> for ThreadCheckerStub<T> {
+    fn ensure(&self) {}
+    #[inline]
+    fn new() -> Self {
+        ThreadCheckerStub(PhantomData)
+    }
+    private_impl! {}
+}
+
+impl<T: PyNativeType> PyClassThreadChecker<T> for ThreadCheckerStub<crate::PyObject> {
+    fn ensure(&self) {}
+    #[inline]
+    fn new() -> Self {
+        ThreadCheckerStub(PhantomData)
+    }
+    private_impl! {}
+}
+
+/// Thread checker for unsendable types.
+/// Panics when the value is accessed by another thread.
+#[doc(hidden)]
+pub struct ThreadCheckerImpl<T>(thread::ThreadId, PhantomData<T>);
+
+impl<T> PyClassThreadChecker<T> for ThreadCheckerImpl<T> {
+    fn ensure(&self) {
+        if thread::current().id() != self.0 {
+            panic!(
+                "{} is unsendable, but sent to another thread!",
+                std::any::type_name::<T>()
+            );
+        }
+    }
+    fn new() -> Self {
+        ThreadCheckerImpl(thread::current().id(), PhantomData)
+    }
+    private_impl! {}
+}
+
+/// Thread checker for types that have `Send` and `extends=...`.
+/// Ensures that `T: Send` and the parent is not accessed by another thread.
+#[doc(hidden)]
+pub struct ThreadCheckerInherited<T: Send, U: PyClassBaseType>(PhantomData<T>, U::ThreadChecker);
+
+impl<T: Send, U: PyClassBaseType> PyClassThreadChecker<T> for ThreadCheckerInherited<T, U> {
+    fn ensure(&self) {
+        self.1.ensure();
+    }
+    fn new() -> Self {
+        ThreadCheckerInherited(PhantomData, U::ThreadChecker::new())
+    }
+    private_impl! {}
+}
+
+/// Trait denoting that this class is suitable to be used as a base type for PyClass.
+pub trait PyClassBaseType: Sized {
+    type LayoutAsBase: PyCellLayout<Self>;
+    type BaseNativeType;
+    type ThreadChecker: PyClassThreadChecker<Self>;
+    type Initializer: PyObjectInit<Self>;
+}
+
+/// All PyClasses can be used as a base type.
+impl<T: PyClass> PyClassBaseType for T {
+    type LayoutAsBase = crate::pycell::PyCell<T>;
+    type BaseNativeType = T::BaseNativeType;
+    type ThreadChecker = T::ThreadChecker;
+    type Initializer = crate::pyclass_init::PyClassInitializer<Self>;
+}
+
+/// Default new implementation
+pub(crate) unsafe extern "C" fn fallback_new(
+    _subtype: *mut ffi::PyTypeObject,
+    _args: *mut ffi::PyObject,
+    _kwds: *mut ffi::PyObject,
+) -> *mut ffi::PyObject {
+    crate::callback_body!(py, {
+        Err::<(), _>(crate::exceptions::PyTypeError::new_err(
+            "No constructor defined",
+        ))
+    })
+}
+
+/// Implementation of tp_dealloc for all pyclasses
+pub(crate) unsafe extern "C" fn tp_dealloc<T: PyClass>(obj: *mut ffi::PyObject) {
+    crate::callback_body!(py, T::Layout::tp_dealloc(obj, py))
+}
+
+pub(crate) unsafe extern "C" fn get_sequence_item_from_mapping(
+    obj: *mut ffi::PyObject,
+    index: ffi::Py_ssize_t,
+) -> *mut ffi::PyObject {
+    let index = ffi::PyLong_FromSsize_t(index);
+    if index.is_null() {
+        return std::ptr::null_mut();
+    }
+    let result = ffi::PyObject_GetItem(obj, index);
+    ffi::Py_DECREF(index);
+    result
+}
+
+pub(crate) unsafe extern "C" fn assign_sequence_item_from_mapping(
+    obj: *mut ffi::PyObject,
+    index: ffi::Py_ssize_t,
+    value: *mut ffi::PyObject,
+) -> c_int {
+    let index = ffi::PyLong_FromSsize_t(index);
+    if index.is_null() {
+        return -1;
+    }
+    let result = if value.is_null() {
+        ffi::PyObject_DelItem(obj, index)
+    } else {
+        ffi::PyObject_SetItem(obj, index, value)
+    };
+    ffi::Py_DECREF(index);
+    result
+}
diff --git a/src/impl_/pyfunction.rs b/src/impl_/pyfunction.rs
index f852e63b..01cd3f08 100644
--- a/src/impl_/pyfunction.rs
+++ b/src/impl_/pyfunction.rs
@@ -1,5 +1,5 @@
 use crate::{
-    class::methods::PyMethodDef, derive_utils::PyFunctionArguments, types::PyCFunction, PyResult,
+    derive_utils::PyFunctionArguments, impl_::pymethods::PyMethodDef, types::PyCFunction, PyResult,
 };
 
 pub trait PyFunctionDef {
diff --git a/src/impl_/pymethods.rs b/src/impl_/pymethods.rs
index 2a8d743a..cbaa2994 100644
--- a/src/impl_/pymethods.rs
+++ b/src/impl_/pymethods.rs
@@ -1,4 +1,8 @@
-use crate::{ffi, FromPyObject, PyAny, PyResult, Python};
+use crate::internal_tricks::{extract_cstr_or_leak_cstring, NulByteInString};
+use crate::{ffi, FromPyObject, PyAny, PyObject, PyResult, Python};
+use std::ffi::CStr;
+use std::fmt;
+use std::os::raw::c_int;
 
 /// Python 3.8 and up - __ipow__ has modulo argument correctly populated.
 #[cfg(Py_3_8)]
@@ -31,3 +35,216 @@ impl IPowModulo {
         unsafe { py.from_borrowed_ptr::<PyAny>(ffi::Py_None()) }.extract()
     }
 }
+
+/// `PyMethodDefType` represents different types of Python callable objects.
+/// It is used by the `#[pymethods]` and `#[pyproto]` annotations.
+#[derive(Debug)]
+pub enum PyMethodDefType {
+    /// Represents class method
+    Class(PyMethodDef),
+    /// Represents static method
+    Static(PyMethodDef),
+    /// Represents normal method
+    Method(PyMethodDef),
+    /// Represents class attribute, used by `#[attribute]`
+    ClassAttribute(PyClassAttributeDef),
+    /// Represents getter descriptor, used by `#[getter]`
+    Getter(PyGetterDef),
+    /// Represents setter descriptor, used by `#[setter]`
+    Setter(PySetterDef),
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum PyMethodType {
+    PyCFunction(PyCFunction),
+    PyCFunctionWithKeywords(PyCFunctionWithKeywords),
+    #[cfg(not(Py_LIMITED_API))]
+    PyCFunctionFastWithKeywords(PyCFunctionFastWithKeywords),
+}
+
+// These newtype structs serve no purpose other than wrapping which are function pointers - because
+// function pointers aren't allowed in const fn, but types wrapping them are!
+#[derive(Clone, Copy, Debug)]
+pub struct PyCFunction(pub ffi::PyCFunction);
+#[derive(Clone, Copy, Debug)]
+pub struct PyCFunctionWithKeywords(pub ffi::PyCFunctionWithKeywords);
+#[cfg(not(Py_LIMITED_API))]
+#[derive(Clone, Copy, Debug)]
+pub struct PyCFunctionFastWithKeywords(pub ffi::_PyCFunctionFastWithKeywords);
+#[derive(Clone, Copy, Debug)]
+pub struct PyGetter(pub ffi::getter);
+#[derive(Clone, Copy, Debug)]
+pub struct PySetter(pub ffi::setter);
+#[derive(Clone, Copy)]
+pub struct PyClassAttributeFactory(pub for<'p> fn(Python<'p>) -> PyObject);
+
+// TODO: it would be nice to use CStr in these types, but then the constructors can't be const fn
+// until `CStr::from_bytes_with_nul_unchecked` is const fn.
+
+#[derive(Clone, Debug)]
+pub struct PyMethodDef {
+    pub(crate) ml_name: &'static str,
+    pub(crate) ml_meth: PyMethodType,
+    pub(crate) ml_flags: c_int,
+    pub(crate) ml_doc: &'static str,
+}
+
+#[derive(Copy, Clone)]
+pub struct PyClassAttributeDef {
+    pub(crate) name: &'static str,
+    pub(crate) meth: PyClassAttributeFactory,
+}
+
+#[derive(Clone, Debug)]
+pub struct PyGetterDef {
+    pub(crate) name: &'static str,
+    pub(crate) meth: PyGetter,
+    doc: &'static str,
+}
+
+#[derive(Clone, Debug)]
+pub struct PySetterDef {
+    pub(crate) name: &'static str,
+    pub(crate) meth: PySetter,
+    doc: &'static str,
+}
+
+unsafe impl Sync for PyMethodDef {}
+
+unsafe impl Sync for PyGetterDef {}
+
+unsafe impl Sync for PySetterDef {}
+
+impl PyMethodDef {
+    /// Define a function with no `*args` and `**kwargs`.
+    pub const fn noargs(name: &'static str, cfunction: PyCFunction, doc: &'static str) -> Self {
+        Self {
+            ml_name: name,
+            ml_meth: PyMethodType::PyCFunction(cfunction),
+            ml_flags: ffi::METH_NOARGS,
+            ml_doc: doc,
+        }
+    }
+
+    /// Define a function that can take `*args` and `**kwargs`.
+    pub const fn cfunction_with_keywords(
+        name: &'static str,
+        cfunction: PyCFunctionWithKeywords,
+        doc: &'static str,
+    ) -> Self {
+        Self {
+            ml_name: name,
+            ml_meth: PyMethodType::PyCFunctionWithKeywords(cfunction),
+            ml_flags: ffi::METH_VARARGS | ffi::METH_KEYWORDS,
+            ml_doc: doc,
+        }
+    }
+
+    /// Define a function that can take `*args` and `**kwargs`.
+    #[cfg(not(Py_LIMITED_API))]
+    pub const fn fastcall_cfunction_with_keywords(
+        name: &'static str,
+        cfunction: PyCFunctionFastWithKeywords,
+        doc: &'static str,
+    ) -> Self {
+        Self {
+            ml_name: name,
+            ml_meth: PyMethodType::PyCFunctionFastWithKeywords(cfunction),
+            ml_flags: ffi::METH_FASTCALL | ffi::METH_KEYWORDS,
+            ml_doc: doc,
+        }
+    }
+
+    pub const fn flags(mut self, flags: c_int) -> Self {
+        self.ml_flags |= flags;
+        self
+    }
+
+    /// Convert `PyMethodDef` to Python method definition struct `ffi::PyMethodDef`
+    pub(crate) fn as_method_def(&self) -> Result<ffi::PyMethodDef, NulByteInString> {
+        let meth = match self.ml_meth {
+            PyMethodType::PyCFunction(meth) => meth.0,
+            PyMethodType::PyCFunctionWithKeywords(meth) => unsafe { std::mem::transmute(meth.0) },
+            #[cfg(not(Py_LIMITED_API))]
+            PyMethodType::PyCFunctionFastWithKeywords(meth) => unsafe {
+                std::mem::transmute(meth.0)
+            },
+        };
+
+        Ok(ffi::PyMethodDef {
+            ml_name: get_name(self.ml_name)?.as_ptr(),
+            ml_meth: Some(meth),
+            ml_flags: self.ml_flags,
+            ml_doc: get_doc(self.ml_doc)?.as_ptr(),
+        })
+    }
+}
+
+impl PyClassAttributeDef {
+    /// Define a class attribute.
+    pub const fn new(name: &'static str, meth: PyClassAttributeFactory) -> Self {
+        Self { name, meth }
+    }
+}
+
+// Manual implementation because `Python<'_>` does not implement `Debug` and
+// trait bounds on `fn` compiler-generated derive impls are too restrictive.
+impl fmt::Debug for PyClassAttributeDef {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("PyClassAttributeDef")
+            .field("name", &self.name)
+            .finish()
+    }
+}
+
+impl PyGetterDef {
+    /// Define a getter.
+    pub const fn new(name: &'static str, getter: PyGetter, doc: &'static str) -> Self {
+        Self {
+            name,
+            meth: getter,
+            doc,
+        }
+    }
+
+    /// Copy descriptor information to `ffi::PyGetSetDef`
+    pub fn copy_to(&self, dst: &mut ffi::PyGetSetDef) {
+        if dst.name.is_null() {
+            dst.name = get_name(self.name).unwrap().as_ptr() as _;
+        }
+        if dst.doc.is_null() {
+            dst.doc = get_doc(self.doc).unwrap().as_ptr() as _;
+        }
+        dst.get = Some(self.meth.0);
+    }
+}
+
+impl PySetterDef {
+    /// Define a setter.
+    pub const fn new(name: &'static str, setter: PySetter, doc: &'static str) -> Self {
+        Self {
+            name,
+            meth: setter,
+            doc,
+        }
+    }
+
+    /// Copy descriptor information to `ffi::PyGetSetDef`
+    pub fn copy_to(&self, dst: &mut ffi::PyGetSetDef) {
+        if dst.name.is_null() {
+            dst.name = get_name(self.name).unwrap().as_ptr() as _;
+        }
+        if dst.doc.is_null() {
+            dst.doc = get_doc(self.doc).unwrap().as_ptr() as _;
+        }
+        dst.set = Some(self.meth.0);
+    }
+}
+
+fn get_name(name: &'static str) -> Result<&'static CStr, NulByteInString> {
+    extract_cstr_or_leak_cstring(name, "Function name cannot contain NUL byte.")
+}
+
+fn get_doc(doc: &'static str) -> Result<&'static CStr, NulByteInString> {
+    extract_cstr_or_leak_cstring(doc, "Document cannot contain NUL byte.")
+}
diff --git a/src/lib.rs b/src/lib.rs
index bb6d6ace..5f11571c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -300,6 +300,30 @@ pub use crate::python::{Python, PythonVersionInfo};
 pub use crate::type_object::PyTypeInfo;
 pub use crate::types::PyAny;
 
+// Old directory layout, to be rethought?
+#[cfg(not(feature = "pyproto"))]
+pub mod class {
+    #[doc(hidden)]
+    pub use crate::impl_::pymethods as methods;
+
+    #[doc(hidden)]
+    pub use self::methods::{
+        PyClassAttributeDef, PyGetterDef, PyMethodDef, PyMethodDefType, PyMethodType, PySetterDef,
+    };
+
+    pub mod basic {
+        pub use crate::pyclass::CompareOp;
+    }
+
+    pub mod pyasync {
+        pub use crate::pyclass::{IterANextOutput, PyIterANextOutput};
+    }
+
+    pub mod iter {
+        pub use crate::pyclass::{IterNextOutput, PyIterNextOutput};
+    }
+}
+
 #[cfg(feature = "macros")]
 #[doc(hidden)]
 pub use {
@@ -317,6 +341,7 @@ mod internal_tricks;
 pub mod buffer;
 #[doc(hidden)]
 pub mod callback;
+#[cfg(feature = "pyproto")]
 pub mod class;
 pub mod conversion;
 mod conversions;
@@ -350,12 +375,16 @@ pub use crate::conversions::*;
 )]
 #[cfg(feature = "macros")]
 pub mod proc_macro {
-    pub use pyo3_macros::{pyclass, pyfunction, pymethods, pymodule, pyproto};
+    #[cfg(feature = "pyproto")]
+    pub use pyo3_macros::pyproto;
+    pub use pyo3_macros::{pyclass, pyfunction, pymethods, pymodule};
 }
 
+#[cfg(all(feature = "macros", feature = "pyproto"))]
+pub use pyo3_macros::pyproto;
 #[cfg(feature = "macros")]
 pub use pyo3_macros::{
-    pyclass, pyfunction, pymethods, pymodule, pyproto, wrap_pyfunction, wrap_pymodule, FromPyObject,
+    pyclass, pyfunction, pymethods, pymodule, wrap_pyfunction, wrap_pymodule, FromPyObject,
 };
 
 #[cfg(feature = "macros")]
diff --git a/src/prelude.rs b/src/prelude.rs
index 52f79ac6..b4dcaedf 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -22,6 +22,7 @@ pub use crate::python::Python;
 pub use crate::types::{PyAny, PyModule};
 
 #[cfg(feature = "macros")]
-pub use pyo3_macros::{
-    pyclass, pyfunction, pymethods, pymodule, pyproto, wrap_pyfunction, FromPyObject,
-};
+pub use pyo3_macros::{pyclass, pyfunction, pymethods, pymodule, wrap_pyfunction, FromPyObject};
+
+#[cfg(all(feature = "macros", feature = "pyproto"))]
+pub use pyo3_macros::pyproto;
diff --git a/src/pycell.rs b/src/pycell.rs
index a0c9e197..b8b2e395 100644
--- a/src/pycell.rs
+++ b/src/pycell.rs
@@ -175,12 +175,11 @@
 //! [Interior Mutability]: https://doc.rust-lang.org/book/ch15-05-interior-mutability.html "RefCell<T> and the Interior Mutability Pattern - The Rust Programming Language"
 
 use crate::exceptions::PyRuntimeError;
-use crate::impl_::pyclass::{PyClassDict, PyClassWeakRef};
+use crate::impl_::pyclass::{PyClassBaseType, PyClassDict, PyClassThreadChecker, PyClassWeakRef};
 use crate::pyclass::PyClass;
 use crate::pyclass_init::PyClassInitializer;
 use crate::type_object::{PyLayout, PySizedLayout};
 use crate::types::PyAny;
-use crate::{class::impl_::PyClassBaseType, class::impl_::PyClassThreadChecker};
 use crate::{
     conversion::{AsPyPointer, FromPyPointer, ToPyObject},
     ffi::PyBaseObject_Type,
diff --git a/src/pyclass.rs b/src/pyclass.rs
index bbbca7f3..7381732d 100644
--- a/src/pyclass.rs
+++ b/src/pyclass.rs
@@ -1,12 +1,10 @@
 //! `PyClass` and related traits.
 use crate::{
-    class::impl_::{
-        assign_sequence_item_from_mapping, fallback_new, get_sequence_item_from_mapping,
-        tp_dealloc, PyClassImpl,
-    },
+    callback::IntoPyCallbackOutput,
     ffi,
-    impl_::pyclass::{PyClassDict, PyClassWeakRef},
-    PyCell, PyErr, PyMethodDefType, PyNativeType, PyResult, PyTypeInfo, Python,
+    impl_::pyclass::{assign_sequence_item_from_mapping, get_sequence_item_from_mapping, fallback_new, tp_dealloc, PyClassDict, PyClassImpl, PyClassWeakRef},
+    IntoPy, IntoPyPointer, PyCell, PyErr, PyMethodDefType, PyNativeType, PyObject, PyResult,
+    PyTypeInfo, Python,
 };
 use std::{
     convert::TryInto,
@@ -435,3 +433,130 @@ const PY_GET_SET_DEF_INIT: ffi::PyGetSetDef = ffi::PyGetSetDef {
     doc: ptr::null_mut(),
     closure: ptr::null_mut(),
 };
+
+/// Operators for the `__richcmp__` method
+#[derive(Debug, Clone, Copy)]
+pub enum CompareOp {
+    /// The *less than* operator.
+    Lt = ffi::Py_LT as isize,
+    /// The *less than or equal to* operator.
+    Le = ffi::Py_LE as isize,
+    /// The equality operator.
+    Eq = ffi::Py_EQ as isize,
+    /// The *not equal to* operator.
+    Ne = ffi::Py_NE as isize,
+    /// The *greater than* operator.
+    Gt = ffi::Py_GT as isize,
+    /// The *greater than or equal to* operator.
+    Ge = ffi::Py_GE as isize,
+}
+
+impl CompareOp {
+    pub fn from_raw(op: c_int) -> Option<Self> {
+        match op {
+            ffi::Py_LT => Some(CompareOp::Lt),
+            ffi::Py_LE => Some(CompareOp::Le),
+            ffi::Py_EQ => Some(CompareOp::Eq),
+            ffi::Py_NE => Some(CompareOp::Ne),
+            ffi::Py_GT => Some(CompareOp::Gt),
+            ffi::Py_GE => Some(CompareOp::Ge),
+            _ => None,
+        }
+    }
+}
+
+/// Output of `__next__` which can either `yield` the next value in the iteration, or
+/// `return` a value to raise `StopIteration` in Python.
+///
+/// See [`PyIterProtocol`](trait.PyIterProtocol.html) for an example.
+pub enum IterNextOutput<T, U> {
+    /// The value yielded by the iterator.
+    Yield(T),
+    /// The `StopIteration` object.
+    Return(U),
+}
+
+pub type PyIterNextOutput = IterNextOutput<PyObject, PyObject>;
+
+impl IntoPyCallbackOutput<*mut ffi::PyObject> for PyIterNextOutput {
+    fn convert(self, _py: Python) -> PyResult<*mut ffi::PyObject> {
+        match self {
+            IterNextOutput::Yield(o) => Ok(o.into_ptr()),
+            IterNextOutput::Return(opt) => Err(crate::exceptions::PyStopIteration::new_err((opt,))),
+        }
+    }
+}
+
+impl<T, U> IntoPyCallbackOutput<PyIterNextOutput> for IterNextOutput<T, U>
+where
+    T: IntoPy<PyObject>,
+    U: IntoPy<PyObject>,
+{
+    fn convert(self, py: Python) -> PyResult<PyIterNextOutput> {
+        match self {
+            IterNextOutput::Yield(o) => Ok(IterNextOutput::Yield(o.into_py(py))),
+            IterNextOutput::Return(o) => Ok(IterNextOutput::Return(o.into_py(py))),
+        }
+    }
+}
+
+impl<T> IntoPyCallbackOutput<PyIterNextOutput> for Option<T>
+where
+    T: IntoPy<PyObject>,
+{
+    fn convert(self, py: Python) -> PyResult<PyIterNextOutput> {
+        match self {
+            Some(o) => Ok(PyIterNextOutput::Yield(o.into_py(py))),
+            None => Ok(PyIterNextOutput::Return(py.None())),
+        }
+    }
+}
+
+/// Output of `__anext__`.
+///
+/// <https://docs.python.org/3/reference/expressions.html#agen.__anext__>
+pub enum IterANextOutput<T, U> {
+    /// An expression which the generator yielded.
+    Yield(T),
+    /// A `StopAsyncIteration` object.
+    Return(U),
+}
+
+/// An [IterANextOutput] of Python objects.
+pub type PyIterANextOutput = IterANextOutput<PyObject, PyObject>;
+
+impl IntoPyCallbackOutput<*mut ffi::PyObject> for PyIterANextOutput {
+    fn convert(self, _py: Python) -> PyResult<*mut ffi::PyObject> {
+        match self {
+            IterANextOutput::Yield(o) => Ok(o.into_ptr()),
+            IterANextOutput::Return(opt) => {
+                Err(crate::exceptions::PyStopAsyncIteration::new_err((opt,)))
+            }
+        }
+    }
+}
+
+impl<T, U> IntoPyCallbackOutput<PyIterANextOutput> for IterANextOutput<T, U>
+where
+    T: IntoPy<PyObject>,
+    U: IntoPy<PyObject>,
+{
+    fn convert(self, py: Python) -> PyResult<PyIterANextOutput> {
+        match self {
+            IterANextOutput::Yield(o) => Ok(IterANextOutput::Yield(o.into_py(py))),
+            IterANextOutput::Return(o) => Ok(IterANextOutput::Return(o.into_py(py))),
+        }
+    }
+}
+
+impl<T> IntoPyCallbackOutput<PyIterANextOutput> for Option<T>
+where
+    T: IntoPy<PyObject>,
+{
+    fn convert(self, py: Python) -> PyResult<PyIterANextOutput> {
+        match self {
+            Some(o) => Ok(PyIterANextOutput::Yield(o.into_py(py))),
+            None => Ok(PyIterANextOutput::Return(py.None())),
+        }
+    }
+}
diff --git a/src/pyclass_init.rs b/src/pyclass_init.rs
index 5fb84a96..b8b2025b 100644
--- a/src/pyclass_init.rs
+++ b/src/pyclass_init.rs
@@ -1,7 +1,6 @@
 //! Contains initialization utilities for `#[pyclass]`.
-use crate::class::impl_::PyClassThreadChecker;
-use crate::impl_::pyclass::{PyClassDict, PyClassWeakRef};
-use crate::{callback::IntoPyCallbackOutput, class::impl_::PyClassBaseType};
+use crate::callback::IntoPyCallbackOutput;
+use crate::impl_::pyclass::{PyClassBaseType, PyClassDict, PyClassThreadChecker, PyClassWeakRef};
 use crate::{ffi, PyCell, PyClass, PyErr, PyResult, Python};
 use crate::{
     ffi::PyTypeObject,
diff --git a/src/types/function.rs b/src/types/function.rs
index fb31b087..4e72eefe 100644
--- a/src/types/function.rs
+++ b/src/types/function.rs
@@ -2,8 +2,9 @@ use crate::derive_utils::PyFunctionArguments;
 use crate::exceptions::PyValueError;
 use crate::prelude::*;
 use crate::{
-    class::methods::{self, PyMethodDef},
-    ffi, types, AsPyPointer,
+    ffi,
+    impl_::pymethods::{self, PyMethodDef},
+    types, AsPyPointer,
 };
 use std::os::raw::c_void;
 
@@ -64,7 +65,11 @@ impl PyCFunction {
         py_or_module: PyFunctionArguments<'a>,
     ) -> PyResult<&'a Self> {
         Self::internal_new(
-            PyMethodDef::cfunction_with_keywords(name, methods::PyCFunctionWithKeywords(fun), doc),
+            PyMethodDef::cfunction_with_keywords(
+                name,
+                pymethods::PyCFunctionWithKeywords(fun),
+                doc,
+            ),
             py_or_module,
         )
     }
@@ -77,7 +82,7 @@ impl PyCFunction {
         py_or_module: PyFunctionArguments<'a>,
     ) -> PyResult<&'a Self> {
         Self::internal_new(
-            PyMethodDef::noargs(name, methods::PyCFunction(fun), doc),
+            PyMethodDef::noargs(name, pymethods::PyCFunction(fun), doc),
             py_or_module,
         )
     }
@@ -115,9 +120,9 @@ impl PyCFunction {
                 ),
             )?
         };
-        let method_def = methods::PyMethodDef::cfunction_with_keywords(
+        let method_def = pymethods::PyMethodDef::cfunction_with_keywords(
             "pyo3-closure",
-            methods::PyCFunctionWithKeywords(run_closure::<F, R>),
+            pymethods::PyCFunctionWithKeywords(run_closure::<F, R>),
             "",
         );
         Self::internal_new_from_pointers(method_def, py, capsule.as_ptr(), std::ptr::null_mut())
diff --git a/src/types/mod.rs b/src/types/mod.rs
index d2765bac..1058a16a 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -196,10 +196,10 @@ macro_rules! pyobject_native_type_sized {
     ($name:ty, $layout:path $(;$generics:ident)*) => {
         unsafe impl $crate::type_object::PyLayout<$name> for $layout {}
         impl $crate::type_object::PySizedLayout<$name> for $layout {}
-        impl<'a, $($generics,)*> $crate::class::impl_::PyClassBaseType for $name {
+        impl<'a, $($generics,)*> $crate::impl_::pyclass::PyClassBaseType for $name {
             type LayoutAsBase = $crate::pycell::PyCellBase<$layout>;
             type BaseNativeType = $name;
-            type ThreadChecker = $crate::class::impl_::ThreadCheckerStub<$crate::PyObject>;
+            type ThreadChecker = $crate::impl_::pyclass::ThreadCheckerStub<$crate::PyObject>;
             type Initializer = $crate::pyclass_init::PyNativeTypeInitializer<Self>;
         }
     }
diff --git a/tests/test_arithmetics_protos.rs b/tests/test_arithmetics_protos.rs
index 86b30c13..b991599a 100644
--- a/tests/test_arithmetics_protos.rs
+++ b/tests/test_arithmetics_protos.rs
@@ -1,5 +1,6 @@
 #![allow(deprecated)] // for deprecated protocol methods
 #![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")]
 
 use pyo3::class::basic::CompareOp;
 use pyo3::class::*;
diff --git a/tests/test_buffer.rs b/tests/test_buffer.rs
index bfdf39fb..70e468c9 100644
--- a/tests/test_buffer.rs
+++ b/tests/test_buffer.rs
@@ -1,10 +1,7 @@
 #![cfg(feature = "macros")]
 #![cfg(not(Py_LIMITED_API))]
 
-use pyo3::{
-    buffer::PyBuffer, class::PyBufferProtocol, exceptions::PyBufferError, ffi, prelude::*,
-    AsPyPointer,
-};
+use pyo3::{buffer::PyBuffer, exceptions::PyBufferError, ffi, prelude::*, AsPyPointer};
 use std::{
     ffi::CStr,
     os::raw::{c_int, c_void},
@@ -28,9 +25,13 @@ struct TestBufferErrors {
     error: Option<TestGetBufferError>,
 }
 
-#[pyproto]
-impl PyBufferProtocol for TestBufferErrors {
-    fn bf_getbuffer(slf: PyRefMut<Self>, view: *mut ffi::Py_buffer, flags: c_int) -> PyResult<()> {
+#[pymethods]
+impl TestBufferErrors {
+    unsafe fn __getbuffer__(
+        slf: PyRefMut<Self>,
+        view: *mut ffi::Py_buffer,
+        flags: c_int,
+    ) -> PyResult<()> {
         if view.is_null() {
             return Err(PyBufferError::new_err("View is null"));
         }
@@ -39,53 +40,47 @@ impl PyBufferProtocol for TestBufferErrors {
             return Err(PyBufferError::new_err("Object is not writable"));
         }
 
-        unsafe {
-            (*view).obj = ffi::_Py_NewRef(slf.as_ptr());
-        }
+        (*view).obj = ffi::_Py_NewRef(slf.as_ptr());
 
         let bytes = &slf.buf;
 
-        unsafe {
-            (*view).buf = bytes.as_ptr() as *mut c_void;
-            (*view).len = bytes.len() as isize;
-            (*view).readonly = 1;
-            (*view).itemsize = std::mem::size_of::<u32>() as isize;
+        (*view).buf = bytes.as_ptr() as *mut c_void;
+        (*view).len = bytes.len() as isize;
+        (*view).readonly = 1;
+        (*view).itemsize = std::mem::size_of::<u32>() as isize;
 
-            let msg = CStr::from_bytes_with_nul(b"I\0").unwrap();
-            (*view).format = msg.as_ptr() as *mut _;
+        let msg = CStr::from_bytes_with_nul(b"I\0").unwrap();
+        (*view).format = msg.as_ptr() as *mut _;
 
-            (*view).ndim = 1;
-            (*view).shape = &mut (*view).len;
+        (*view).ndim = 1;
+        (*view).shape = &mut (*view).len;
 
-            (*view).strides = &mut (*view).itemsize;
+        (*view).strides = &mut (*view).itemsize;
 
-            (*view).suboffsets = ptr::null_mut();
-            (*view).internal = ptr::null_mut();
+        (*view).suboffsets = ptr::null_mut();
+        (*view).internal = ptr::null_mut();
 
-            if let Some(err) = &slf.error {
-                use TestGetBufferError::*;
-                match err {
-                    NullShape => {
-                        (*view).shape = std::ptr::null_mut();
-                    }
-                    NullStrides => {
-                        (*view).strides = std::ptr::null_mut();
-                    }
-                    IncorrectItemSize => {
-                        (*view).itemsize += 1;
-                    }
-                    IncorrectFormat => {
-                        (*view).format = CStr::from_bytes_with_nul(b"B\0").unwrap().as_ptr() as _;
-                    }
-                    IncorrectAlignment => (*view).buf = (*view).buf.add(1),
+        if let Some(err) = &slf.error {
+            use TestGetBufferError::*;
+            match err {
+                NullShape => {
+                    (*view).shape = std::ptr::null_mut();
                 }
+                NullStrides => {
+                    (*view).strides = std::ptr::null_mut();
+                }
+                IncorrectItemSize => {
+                    (*view).itemsize += 1;
+                }
+                IncorrectFormat => {
+                    (*view).format = CStr::from_bytes_with_nul(b"B\0").unwrap().as_ptr() as _;
+                }
+                IncorrectAlignment => (*view).buf = (*view).buf.add(1),
             }
         }
 
         Ok(())
     }
-
-    fn bf_releasebuffer(_slf: PyRefMut<Self>, _view: *mut ffi::Py_buffer) {}
 }
 
 #[test]
diff --git a/tests/test_buffer_protocol_pyproto.rs b/tests/test_buffer_protocol_pyproto.rs
index 81c5a7f0..1ee36f15 100644
--- a/tests/test_buffer_protocol_pyproto.rs
+++ b/tests/test_buffer_protocol_pyproto.rs
@@ -1,4 +1,5 @@
 #![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")]
 #![cfg(not(Py_LIMITED_API))]
 
 use pyo3::buffer::PyBuffer;
diff --git a/tests/test_frompyobject.rs b/tests/test_frompyobject.rs
index 0a213acb..17428ced 100644
--- a/tests/test_frompyobject.rs
+++ b/tests/test_frompyobject.rs
@@ -3,7 +3,6 @@
 use pyo3::exceptions::PyValueError;
 use pyo3::prelude::*;
 use pyo3::types::{PyDict, PyString, PyTuple};
-use pyo3::PyMappingProtocol;
 
 #[macro_use]
 mod common;
@@ -39,8 +38,8 @@ pub struct PyA {
     foo: Option<String>,
 }
 
-#[pyproto]
-impl PyMappingProtocol for PyA {
+#[pymethods]
+impl PyA {
     fn __getitem__(&self, key: String) -> pyo3::PyResult<String> {
         if key == "t" {
             Ok("bar".into())
diff --git a/tests/test_gc.rs b/tests/test_gc.rs
index bf0ca182..92854473 100644
--- a/tests/test_gc.rs
+++ b/tests/test_gc.rs
@@ -1,4 +1,5 @@
 #![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")] // FIXME: #[pymethods] to support gc protocol
 
 use pyo3::class::PyGCProtocol;
 use pyo3::class::PyTraverseError;
diff --git a/tests/test_gc_pyproto.rs b/tests/test_gc_pyproto.rs
new file mode 100644
index 00000000..cf6793b7
--- /dev/null
+++ b/tests/test_gc_pyproto.rs
@@ -0,0 +1,282 @@
+#![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")]
+
+use pyo3::class::PyGCProtocol;
+use pyo3::class::PyTraverseError;
+use pyo3::class::PyVisit;
+use pyo3::prelude::*;
+use pyo3::type_object::PyTypeObject;
+use pyo3::{py_run, AsPyPointer, PyCell, PyTryInto};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+
+mod common;
+
+#[pyclass(freelist = 2)]
+struct ClassWithFreelist {}
+
+#[test]
+fn class_with_freelist() {
+    let ptr;
+    {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+
+        let inst = Py::new(py, ClassWithFreelist {}).unwrap();
+        let _inst2 = Py::new(py, ClassWithFreelist {}).unwrap();
+        ptr = inst.as_ptr();
+        drop(inst);
+    }
+
+    {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+
+        let inst3 = Py::new(py, ClassWithFreelist {}).unwrap();
+        assert_eq!(ptr, inst3.as_ptr());
+
+        let inst4 = Py::new(py, ClassWithFreelist {}).unwrap();
+        assert_ne!(ptr, inst4.as_ptr())
+    }
+}
+
+struct TestDropCall {
+    drop_called: Arc<AtomicBool>,
+}
+
+impl Drop for TestDropCall {
+    fn drop(&mut self) {
+        self.drop_called.store(true, Ordering::Relaxed);
+    }
+}
+
+#[allow(dead_code)]
+#[pyclass]
+struct DataIsDropped {
+    member1: TestDropCall,
+    member2: TestDropCall,
+}
+
+#[test]
+fn data_is_dropped() {
+    let drop_called1 = Arc::new(AtomicBool::new(false));
+    let drop_called2 = Arc::new(AtomicBool::new(false));
+
+    {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+        let data_is_dropped = DataIsDropped {
+            member1: TestDropCall {
+                drop_called: Arc::clone(&drop_called1),
+            },
+            member2: TestDropCall {
+                drop_called: Arc::clone(&drop_called2),
+            },
+        };
+        let inst = Py::new(py, data_is_dropped).unwrap();
+        assert!(!drop_called1.load(Ordering::Relaxed));
+        assert!(!drop_called2.load(Ordering::Relaxed));
+        drop(inst);
+    }
+
+    assert!(drop_called1.load(Ordering::Relaxed));
+    assert!(drop_called2.load(Ordering::Relaxed));
+}
+
+#[allow(dead_code)]
+#[pyclass]
+struct GcIntegration {
+    self_ref: PyObject,
+    dropped: TestDropCall,
+}
+
+#[pyproto]
+impl PyGCProtocol for GcIntegration {
+    fn __traverse__(&self, visit: PyVisit) -> Result<(), PyTraverseError> {
+        visit.call(&self.self_ref)
+    }
+
+    fn __clear__(&mut self) {
+        let gil = Python::acquire_gil();
+        self.self_ref = gil.python().None();
+    }
+}
+
+#[test]
+fn gc_integration() {
+    let drop_called = Arc::new(AtomicBool::new(false));
+
+    {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+        let inst = PyCell::new(
+            py,
+            GcIntegration {
+                self_ref: py.None(),
+                dropped: TestDropCall {
+                    drop_called: Arc::clone(&drop_called),
+                },
+            },
+        )
+        .unwrap();
+
+        let mut borrow = inst.borrow_mut();
+        borrow.self_ref = inst.to_object(py);
+    }
+
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    py.run("import gc; gc.collect()", None, None).unwrap();
+    assert!(drop_called.load(Ordering::Relaxed));
+}
+
+#[pyclass(gc)]
+struct GcIntegration2 {}
+
+#[pyproto]
+impl PyGCProtocol for GcIntegration2 {
+    fn __traverse__(&self, _visit: PyVisit) -> Result<(), PyTraverseError> {
+        Ok(())
+    }
+    fn __clear__(&mut self) {}
+}
+
+#[test]
+fn gc_integration2() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let inst = PyCell::new(py, GcIntegration2 {}).unwrap();
+    py_run!(py, inst, "import gc; assert inst in gc.get_objects()");
+}
+
+#[pyclass(subclass)]
+struct BaseClassWithDrop {
+    data: Option<Arc<AtomicBool>>,
+}
+
+#[pymethods]
+impl BaseClassWithDrop {
+    #[new]
+    fn new() -> BaseClassWithDrop {
+        BaseClassWithDrop { data: None }
+    }
+}
+
+impl Drop for BaseClassWithDrop {
+    fn drop(&mut self) {
+        if let Some(data) = &self.data {
+            data.store(true, Ordering::Relaxed);
+        }
+    }
+}
+
+#[pyclass(extends = BaseClassWithDrop)]
+struct SubClassWithDrop {
+    data: Option<Arc<AtomicBool>>,
+}
+
+#[pymethods]
+impl SubClassWithDrop {
+    #[new]
+    fn new() -> (Self, BaseClassWithDrop) {
+        (
+            SubClassWithDrop { data: None },
+            BaseClassWithDrop { data: None },
+        )
+    }
+}
+
+impl Drop for SubClassWithDrop {
+    fn drop(&mut self) {
+        if let Some(data) = &self.data {
+            data.store(true, Ordering::Relaxed);
+        }
+    }
+}
+
+#[test]
+fn inheritance_with_new_methods_with_drop() {
+    let drop_called1 = Arc::new(AtomicBool::new(false));
+    let drop_called2 = Arc::new(AtomicBool::new(false));
+
+    {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+        let _typebase = py.get_type::<BaseClassWithDrop>();
+        let typeobj = py.get_type::<SubClassWithDrop>();
+        let inst = typeobj.call((), None).unwrap();
+
+        let obj: &PyCell<SubClassWithDrop> = inst.try_into().unwrap();
+        let mut obj_ref_mut = obj.borrow_mut();
+        obj_ref_mut.data = Some(Arc::clone(&drop_called1));
+        let base: &mut BaseClassWithDrop = obj_ref_mut.as_mut();
+        base.data = Some(Arc::clone(&drop_called2));
+    }
+
+    assert!(drop_called1.load(Ordering::Relaxed));
+    assert!(drop_called2.load(Ordering::Relaxed));
+}
+
+#[pyclass(gc)]
+struct TraversableClass {
+    traversed: AtomicBool,
+}
+
+impl TraversableClass {
+    fn new() -> Self {
+        Self {
+            traversed: AtomicBool::new(false),
+        }
+    }
+}
+
+#[pyproto]
+impl PyGCProtocol for TraversableClass {
+    fn __clear__(&mut self) {}
+    fn __traverse__(&self, _visit: PyVisit) -> Result<(), PyTraverseError> {
+        self.traversed.store(true, Ordering::Relaxed);
+        Ok(())
+    }
+}
+
+unsafe fn get_type_traverse(tp: *mut pyo3::ffi::PyTypeObject) -> Option<pyo3::ffi::traverseproc> {
+    std::mem::transmute(pyo3::ffi::PyType_GetSlot(tp, pyo3::ffi::Py_tp_traverse))
+}
+
+#[test]
+fn gc_during_borrow() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    unsafe {
+        // declare a dummy visitor function
+        extern "C" fn novisit(
+            _object: *mut pyo3::ffi::PyObject,
+            _arg: *mut core::ffi::c_void,
+        ) -> std::os::raw::c_int {
+            0
+        }
+
+        // get the traverse function
+        let ty = TraversableClass::type_object(py).as_type_ptr();
+        let traverse = get_type_traverse(ty).unwrap();
+
+        // create an object and check that traversing it works normally
+        // when it's not borrowed
+        let cell = PyCell::new(py, TraversableClass::new()).unwrap();
+        let obj = cell.to_object(py);
+        assert!(!cell.borrow().traversed.load(Ordering::Relaxed));
+        traverse(obj.as_ptr(), novisit, std::ptr::null_mut());
+        assert!(cell.borrow().traversed.load(Ordering::Relaxed));
+
+        // create an object and check that it is not traversed if the GC
+        // is invoked while it is already borrowed mutably
+        let cell2 = PyCell::new(py, TraversableClass::new()).unwrap();
+        let obj2 = cell2.to_object(py);
+        let guard = cell2.borrow_mut();
+        assert!(!guard.traversed.load(Ordering::Relaxed));
+        traverse(obj2.as_ptr(), novisit, std::ptr::null_mut());
+        assert!(!guard.traversed.load(Ordering::Relaxed));
+        drop(guard);
+    }
+}
diff --git a/tests/test_mapping.rs b/tests/test_mapping.rs
index 221496b5..0e65f60d 100644
--- a/tests/test_mapping.rs
+++ b/tests/test_mapping.rs
@@ -7,7 +7,6 @@ use pyo3::prelude::*;
 use pyo3::py_run;
 use pyo3::types::IntoPyDict;
 use pyo3::types::PyList;
-use pyo3::PyMappingProtocol;
 
 mod common;
 
@@ -33,10 +32,7 @@ impl Mapping {
             })
         }
     }
-}
 
-#[pyproto]
-impl PyMappingProtocol for Mapping {
     fn __len__(&self) -> usize {
         self.index.len()
     }
diff --git a/tests/test_mapping_pyproto.rs b/tests/test_mapping_pyproto.rs
new file mode 100644
index 00000000..f82b876a
--- /dev/null
+++ b/tests/test_mapping_pyproto.rs
@@ -0,0 +1,110 @@
+#![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")]
+
+use std::collections::HashMap;
+
+use pyo3::exceptions::PyKeyError;
+use pyo3::prelude::*;
+use pyo3::py_run;
+use pyo3::types::IntoPyDict;
+use pyo3::types::PyList;
+use pyo3::PyMappingProtocol;
+
+mod common;
+
+#[pyclass]
+struct Mapping {
+    index: HashMap<String, usize>,
+}
+
+#[pymethods]
+impl Mapping {
+    #[new]
+    fn new(elements: Option<&PyList>) -> PyResult<Self> {
+        if let Some(pylist) = elements {
+            let mut elems = HashMap::with_capacity(pylist.len());
+            for (i, pyelem) in pylist.into_iter().enumerate() {
+                let elem = String::extract(pyelem)?;
+                elems.insert(elem, i);
+            }
+            Ok(Self { index: elems })
+        } else {
+            Ok(Self {
+                index: HashMap::new(),
+            })
+        }
+    }
+}
+
+#[pyproto]
+impl PyMappingProtocol for Mapping {
+    fn __len__(&self) -> usize {
+        self.index.len()
+    }
+
+    fn __getitem__(&self, query: String) -> PyResult<usize> {
+        self.index
+            .get(&query)
+            .copied()
+            .ok_or_else(|| PyKeyError::new_err("unknown key"))
+    }
+
+    fn __setitem__(&mut self, key: String, value: usize) {
+        self.index.insert(key, value);
+    }
+
+    fn __delitem__(&mut self, key: String) -> PyResult<()> {
+        if self.index.remove(&key).is_none() {
+            Err(PyKeyError::new_err("unknown key"))
+        } else {
+            Ok(())
+        }
+    }
+}
+
+/// Return a dict with `m = Mapping(['1', '2', '3'])`.
+fn map_dict(py: Python) -> &pyo3::types::PyDict {
+    let d = [("Mapping", py.get_type::<Mapping>())].into_py_dict(py);
+    py_run!(py, *d, "m = Mapping(['1', '2', '3'])");
+    d
+}
+
+#[test]
+fn test_getitem() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let d = map_dict(py);
+
+    py_assert!(py, *d, "m['1'] == 0");
+    py_assert!(py, *d, "m['2'] == 1");
+    py_assert!(py, *d, "m['3'] == 2");
+    py_expect_exception!(py, *d, "print(m['4'])", PyKeyError);
+}
+
+#[test]
+fn test_setitem() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let d = map_dict(py);
+
+    py_run!(py, *d, "m['1'] = 4; assert m['1'] == 4");
+    py_run!(py, *d, "m['0'] = 0; assert m['0'] == 0");
+    py_assert!(py, *d, "len(m) == 4");
+    py_expect_exception!(py, *d, "m[0] = 'hello'", PyTypeError);
+    py_expect_exception!(py, *d, "m[0] = -1", PyTypeError);
+}
+
+#[test]
+fn test_delitem() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let d = map_dict(py);
+    py_run!(
+        py,
+        *d,
+        "del m['1']; assert len(m) == 2 and m['2'] == 1 and m['3'] == 2"
+    );
+    py_expect_exception!(py, *d, "del m[-1]", PyTypeError);
+    py_expect_exception!(py, *d, "del m['4']", PyKeyError);
+}
diff --git a/tests/test_pyproto.rs b/tests/test_pyproto.rs
index 7e15d73e..0d963c1a 100644
--- a/tests/test_pyproto.rs
+++ b/tests/test_pyproto.rs
@@ -1,4 +1,5 @@
 #![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")]
 
 use pyo3::class::{
     PyAsyncProtocol, PyDescrProtocol, PyIterProtocol, PyMappingProtocol, PyObjectProtocol,
diff --git a/tests/test_pyself.rs b/tests/test_pyself.rs
index 7e2eb50f..86f4f291 100644
--- a/tests/test_pyself.rs
+++ b/tests/test_pyself.rs
@@ -3,7 +3,7 @@
 //! Test slf: PyRef/PyMutRef<Self>(especially, slf.into::<Py>) works
 use pyo3::prelude::*;
 use pyo3::types::{PyBytes, PyString};
-use pyo3::{PyCell, PyIterProtocol};
+use pyo3::PyCell;
 use std::collections::HashMap;
 
 mod common;
@@ -54,9 +54,9 @@ struct Iter {
     idx: usize,
 }
 
-#[pyproto]
-impl PyIterProtocol for Iter {
-    fn __iter__(slf: PyRef<Self>) -> PyRef<'p, Self> {
+#[pymethods]
+impl Iter {
+    fn __iter__(slf: PyRef<Self>) -> PyRef<Self> {
         slf
     }
 
diff --git a/tests/test_sequence.rs b/tests/test_sequence.rs
index eebd8650..e156b9ff 100644
--- a/tests/test_sequence.rs
+++ b/tests/test_sequence.rs
@@ -1,4 +1,5 @@
 #![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")] // FIXME: change this to use #[pymethods] once supports sequence protocol
 
 use pyo3::class::PySequenceProtocol;
 use pyo3::exceptions::{PyIndexError, PyValueError};
diff --git a/tests/test_sequence_pyproto.rs b/tests/test_sequence_pyproto.rs
new file mode 100644
index 00000000..db4b6d41
--- /dev/null
+++ b/tests/test_sequence_pyproto.rs
@@ -0,0 +1,304 @@
+#![cfg(feature = "macros")]
+#![cfg(feature = "pyproto")]
+
+use pyo3::class::PySequenceProtocol;
+use pyo3::exceptions::{PyIndexError, PyValueError};
+use pyo3::prelude::*;
+use pyo3::types::{IntoPyDict, PyList};
+
+use pyo3::py_run;
+
+mod common;
+
+#[pyclass]
+struct ByteSequence {
+    elements: Vec<u8>,
+}
+
+#[pymethods]
+impl ByteSequence {
+    #[new]
+    fn new(elements: Option<&PyList>) -> PyResult<Self> {
+        if let Some(pylist) = elements {
+            let mut elems = Vec::with_capacity(pylist.len());
+            for pyelem in pylist.into_iter() {
+                let elem = u8::extract(pyelem)?;
+                elems.push(elem);
+            }
+            Ok(Self { elements: elems })
+        } else {
+            Ok(Self {
+                elements: Vec::new(),
+            })
+        }
+    }
+}
+
+#[pyproto]
+impl PySequenceProtocol for ByteSequence {
+    fn __len__(&self) -> usize {
+        self.elements.len()
+    }
+
+    fn __getitem__(&self, idx: isize) -> PyResult<u8> {
+        self.elements
+            .get(idx as usize)
+            .copied()
+            .ok_or_else(|| PyIndexError::new_err("list index out of range"))
+    }
+
+    fn __setitem__(&mut self, idx: isize, value: u8) {
+        self.elements[idx as usize] = value;
+    }
+
+    fn __delitem__(&mut self, idx: isize) -> PyResult<()> {
+        if (idx < self.elements.len() as isize) && (idx >= 0) {
+            self.elements.remove(idx as usize);
+            Ok(())
+        } else {
+            Err(PyIndexError::new_err("list index out of range"))
+        }
+    }
+
+    fn __contains__(&self, other: &PyAny) -> bool {
+        match u8::extract(other) {
+            Ok(x) => self.elements.contains(&x),
+            Err(_) => false,
+        }
+    }
+
+    fn __concat__(&self, other: PyRef<'p, Self>) -> Self {
+        let mut elements = self.elements.clone();
+        elements.extend_from_slice(&other.elements);
+        Self { elements }
+    }
+
+    fn __repeat__(&self, count: isize) -> PyResult<Self> {
+        if count >= 0 {
+            let mut elements = Vec::with_capacity(self.elements.len() * count as usize);
+            for _ in 0..count {
+                elements.extend(&self.elements);
+            }
+            Ok(Self { elements })
+        } else {
+            Err(PyValueError::new_err("invalid repeat count"))
+        }
+    }
+}
+
+/// Return a dict with `s = ByteSequence([1, 2, 3])`.
+fn seq_dict(py: Python) -> &pyo3::types::PyDict {
+    let d = [("ByteSequence", py.get_type::<ByteSequence>())].into_py_dict(py);
+    // Though we can construct `s` in Rust, let's test `__new__` works.
+    py_run!(py, *d, "s = ByteSequence([1, 2, 3])");
+    d
+}
+
+#[test]
+fn test_getitem() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let d = seq_dict(py);
+
+    py_assert!(py, *d, "s[0] == 1");
+    py_assert!(py, *d, "s[1] == 2");
+    py_assert!(py, *d, "s[2] == 3");
+    py_expect_exception!(py, *d, "print(s[-4])", PyIndexError);
+    py_expect_exception!(py, *d, "print(s[4])", PyIndexError);
+}
+
+#[test]
+fn test_setitem() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let d = seq_dict(py);
+
+    py_run!(py, *d, "s[0] = 4; assert list(s) == [4, 2, 3]");
+    py_expect_exception!(py, *d, "s[0] = 'hello'", PyTypeError);
+}
+
+#[test]
+fn test_delitem() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let d = [("ByteSequence", py.get_type::<ByteSequence>())].into_py_dict(py);
+
+    py_run!(
+        py,
+        *d,
+        "s = ByteSequence([1, 2, 3]); del s[0]; assert list(s) == [2, 3]"
+    );
+    py_run!(
+        py,
+        *d,
+        "s = ByteSequence([1, 2, 3]); del s[1]; assert list(s) == [1, 3]"
+    );
+    py_run!(
+        py,
+        *d,
+        "s = ByteSequence([1, 2, 3]); del s[-1]; assert list(s) == [1, 2]"
+    );
+    py_run!(
+        py,
+        *d,
+        "s = ByteSequence([1, 2, 3]); del s[-2]; assert list(s) == [1, 3]"
+    );
+    py_expect_exception!(
+        py,
+        *d,
+        "s = ByteSequence([1, 2, 3]); del s[-4]; print(list(s))",
+        PyIndexError
+    );
+    py_expect_exception!(
+        py,
+        *d,
+        "s = ByteSequence([1, 2, 3]); del s[4]",
+        PyIndexError
+    );
+}
+
+#[test]
+fn test_contains() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let d = seq_dict(py);
+
+    py_assert!(py, *d, "1 in s");
+    py_assert!(py, *d, "2 in s");
+    py_assert!(py, *d, "3 in s");
+    py_assert!(py, *d, "4 not in s");
+    py_assert!(py, *d, "'hello' not in s");
+}
+
+#[test]
+fn test_concat() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let d = seq_dict(py);
+
+    py_run!(
+        py,
+        *d,
+        "s1 = ByteSequence([1, 2]); s2 = ByteSequence([3, 4]); assert list(s1 + s2) == [1, 2, 3, 4]"
+    );
+    py_expect_exception!(
+        py,
+        *d,
+        "s1 = ByteSequence([1, 2]); s2 = 'hello'; s1 + s2",
+        PyTypeError
+    );
+}
+
+#[test]
+fn test_inplace_concat() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let d = seq_dict(py);
+
+    py_run!(
+        py,
+        *d,
+        "s += ByteSequence([4, 5]); assert list(s) == [1, 2, 3, 4, 5]"
+    );
+    py_expect_exception!(py, *d, "s += 'hello'", PyTypeError);
+}
+
+#[test]
+fn test_repeat() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let d = seq_dict(py);
+
+    py_run!(py, *d, "s2 = s * 2; assert list(s2) == [1, 2, 3, 1, 2, 3]");
+    py_expect_exception!(py, *d, "s2 = s * -1", PyValueError);
+}
+
+#[test]
+fn test_inplace_repeat() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let d = [("ByteSequence", py.get_type::<ByteSequence>())].into_py_dict(py);
+
+    py_run!(
+        py,
+        *d,
+        "s = ByteSequence([1, 2]); s *= 3; assert list(s) == [1, 2, 1, 2, 1, 2]"
+    );
+    py_expect_exception!(py, *d, "s = ByteSequence([1, 2]); s *= -1", PyValueError);
+}
+
+// Check that #[pyo3(get, set)] works correctly for Vec<PyObject>
+
+#[pyclass]
+struct GenericList {
+    #[pyo3(get, set)]
+    items: Vec<PyObject>,
+}
+
+#[test]
+fn test_generic_list_get() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let list: PyObject = GenericList {
+        items: [1, 2, 3].iter().map(|i| i.to_object(py)).collect(),
+    }
+    .into_py(py);
+
+    py_assert!(py, list, "list.items == [1, 2, 3]");
+}
+
+#[test]
+fn test_generic_list_set() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let list = PyCell::new(py, GenericList { items: vec![] }).unwrap();
+
+    py_run!(py, list, "list.items = [1, 2, 3]");
+    assert_eq!(
+        list.borrow().items,
+        vec![1.to_object(py), 2.to_object(py), 3.to_object(py)]
+    );
+}
+
+#[pyclass]
+struct OptionList {
+    #[pyo3(get, set)]
+    items: Vec<Option<i64>>,
+}
+
+#[pyproto]
+impl PySequenceProtocol for OptionList {
+    fn __getitem__(&self, idx: isize) -> PyResult<Option<i64>> {
+        match self.items.get(idx as usize) {
+            Some(x) => Ok(*x),
+            None => Err(PyIndexError::new_err("Index out of bounds")),
+        }
+    }
+}
+
+#[test]
+fn test_option_list_get() {
+    // Regression test for #798
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+
+    let list = PyCell::new(
+        py,
+        OptionList {
+            items: vec![Some(1), None],
+        },
+    )
+    .unwrap();
+
+    py_assert!(py, list, "list[0] == 1");
+    py_assert!(py, list, "list[1] == None");
+    py_expect_exception!(py, list, "list[2]", PyIndexError);
+}
diff --git a/tests/ui/abi3_nativetype_inheritance.stderr b/tests/ui/abi3_nativetype_inheritance.stderr
index 762250a4..360a0a45 100644
--- a/tests/ui/abi3_nativetype_inheritance.stderr
+++ b/tests/ui/abi3_nativetype_inheritance.stderr
@@ -15,7 +15,7 @@ error[E0277]: the trait bound `PyDict: PyClass` is not satisfied
     |
     = note: required because of the requirements on the impl of `PyClassBaseType` for `PyDict`
 note: required by a bound in `ThreadCheckerInherited`
-   --> src/class/impl_.rs
+   --> src/impl_/pyclass.rs
     |
     | pub struct ThreadCheckerInherited<T: Send, U: PyClassBaseType>(PhantomData<T>, U::ThreadChecker);
     |                                               ^^^^^^^^^^^^^^^ required by this bound in `ThreadCheckerInherited`
diff --git a/tests/ui/not_send.stderr b/tests/ui/not_send.stderr
index 166a3d6f..d4a0d4d4 100644
--- a/tests/ui/not_send.stderr
+++ b/tests/ui/not_send.stderr
@@ -6,9 +6,9 @@ error[E0277]: `*mut pyo3::Python<'static>` cannot be shared between threads safe
     |
     = help: within `pyo3::Python<'_>`, the trait `Sync` is not implemented for `*mut pyo3::Python<'static>`
     = note: required because it appears within the type `PhantomData<*mut pyo3::Python<'static>>`
-    = note: required because it appears within the type `pyo3::impl_::not_send::NotSend`
-    = note: required because it appears within the type `(&GILGuard, pyo3::impl_::not_send::NotSend)`
-    = note: required because it appears within the type `PhantomData<(&GILGuard, pyo3::impl_::not_send::NotSend)>`
+    = note: required because it appears within the type `impl_::not_send::NotSend`
+    = note: required because it appears within the type `(&GILGuard, impl_::not_send::NotSend)`
+    = note: required because it appears within the type `PhantomData<(&GILGuard, impl_::not_send::NotSend)>`
     = note: required because it appears within the type `pyo3::Python<'_>`
     = note: required because of the requirements on the impl of `Send` for `&pyo3::Python<'_>`
     = note: required because it appears within the type `[closure@$DIR/tests/ui/not_send.rs:4:22: 4:38]`
diff --git a/tests/ui/pyclass_send.stderr b/tests/ui/pyclass_send.stderr
index 531a4e9d..287430ac 100644
--- a/tests/ui/pyclass_send.stderr
+++ b/tests/ui/pyclass_send.stderr
@@ -11,7 +11,7 @@ note: required because it appears within the type `NotThreadSafe`
 5   | struct NotThreadSafe {
     |        ^^^^^^^^^^^^^
 note: required by a bound in `ThreadCheckerStub`
-   --> src/class/impl_.rs
+   --> src/impl_/pyclass.rs
     |
     | pub struct ThreadCheckerStub<T: Send>(PhantomData<T>);
     |                                 ^^^^ required by this bound in `ThreadCheckerStub`