Resolve some clippy complains

src/object.rs

@@ -162,7 +162,7 @@ impl PyObject {
     where
         D: FromPyObject<'p>,
     {
-        FromPyObject::extract(self.as_ref(py).into())
+        FromPyObject::extract(self.as_ref(py))
     }
 
     /// Retrieves an attribute value.

src/pyclass.rs

@@ -307,12 +307,21 @@ pub struct PyClassInitializer<T: PyTypeInfo> {
     super_init: Option<*mut PyClassInitializer<T::BaseType>>,
 }
 
+impl<T: PyTypeInfo> Default for PyClassInitializer<T> {
+    fn default() -> Self {
+        Self {
+            init: None,
+            super_init: None,
+        }
+    }
+}
+
 impl<T: PyTypeInfo> PyClassInitializer<T> {
     /// Construct `PyClassInitializer` for specified value `value`.
     ///
     /// Same as
     /// ```ignore
-    /// let mut init = PyClassInitializer::<T>();
+    /// let mut init = PyClassInitializer::default::<T>();
     /// init.init(value);
     /// ```
     pub fn from_value(value: T) -> Self {
@@ -322,17 +331,8 @@ impl<T: PyTypeInfo> PyClassInitializer<T> {
         }
     }
 
-    /// Make new `PyClassInitializer` with empty values.
-    pub fn new() -> Self {
-        PyClassInitializer {
-            init: None,
-            super_init: None,
-        }
-    }
-
     #[must_use]
-    #[doc(hiddden)]
-    pub fn init_class(self, shell: &mut T::ConcreteLayout) -> PyResult<()> {
+    fn init_class(self, shell: &mut T::ConcreteLayout) -> PyResult<()> {
         macro_rules! raise_err {
             ($name: path) => {
                 return Err(PyErr::new::<RuntimeError, _>(format!(
@@ -369,7 +369,7 @@ impl<T: PyTypeInfo> PyClassInitializer<T> {
         if let Some(super_init) = self.super_init {
             return unsafe { &mut *super_init };
         }
-        let super_init = Box::into_raw(Box::new(PyClassInitializer::new()));
+        let super_init = Box::into_raw(Box::new(PyClassInitializer::default()));
         self.super_init = Some(super_init);
         unsafe { &mut *super_init }
     }

src/pyclass_slots.rs

@@ -1,5 +1,4 @@
 //! This module contains additional fields pf pyclass
-// TODO(kngwyu): Add vectorcall support
 use crate::{ffi, Python};
 
 const POINTER_SIZE: isize = std::mem::size_of::<*mut ffi::PyObject>() as _;
@@ -8,7 +7,7 @@ const POINTER_SIZE: isize = std::mem::size_of::<*mut ffi::PyObject>() as _;
 pub trait PyClassDict {
     const OFFSET: Option<isize> = None;
     fn new() -> Self;
-    fn clear_dict(&mut self, _py: Python) {}
+    unsafe fn clear_dict(&mut self, _py: Python) {}
     private_decl! {}
 }
 
@@ -16,7 +15,7 @@ pub trait PyClassDict {
 pub trait PyClassWeakRef {
     const OFFSET: Option<isize> = None;
     fn new() -> Self;
-    fn clear_weakrefs(&mut self, _obj: *mut ffi::PyObject, _py: Python) {}
+    unsafe fn clear_weakrefs(&mut self, _obj: *mut ffi::PyObject, _py: Python) {}
     private_decl! {}
 }
 
@@ -47,9 +46,9 @@ impl PyClassDict for PyClassDictSlot {
     fn new() -> Self {
         Self(std::ptr::null_mut())
     }
-    fn clear_dict(&mut self, _py: Python) {
-        if self.0 != std::ptr::null_mut() {
-            unsafe { ffi::PyDict_Clear(self.0) }
+    unsafe fn clear_dict(&mut self, _py: Python) {
+        if !self.0.is_null() {
+            ffi::PyDict_Clear(self.0)
         }
     }
 }
@@ -64,9 +63,9 @@ impl PyClassWeakRef for PyClassWeakRefSlot {
     fn new() -> Self {
         Self(std::ptr::null_mut())
     }
-    fn clear_weakrefs(&mut self, obj: *mut ffi::PyObject, _py: Python) {
-        if self.0 != std::ptr::null_mut() {
-            unsafe { ffi::PyObject_ClearWeakRefs(obj) }
+    unsafe fn clear_weakrefs(&mut self, obj: *mut ffi::PyObject, _py: Python) {
+        if !self.0.is_null() {
+            ffi::PyObject_ClearWeakRefs(obj)
         }
     }
 }

src/type_object.rs

@@ -7,7 +7,11 @@ use crate::types::{PyAny, PyType};
 use crate::{ffi, AsPyPointer, Python};
 use std::ptr::NonNull;
 
-/// TODO: write document
+/// `T: PyObjectLayout<U>` represents that `T` is a concrete representaion of `U` in Python heap.
+/// E.g., `PyClassShell` is a concrete representaion of all `pyclass`es, and `ffi::PyObject`
+/// is of `PyAny`.
+///
+/// This trait is intended to be used internally.
 pub trait PyObjectLayout<T: PyTypeInfo> {
     const NEED_INIT: bool = false;
     const IS_NATIVE_TYPE: bool = true;
@@ -19,6 +23,8 @@ pub trait PyObjectLayout<T: PyTypeInfo> {
     unsafe fn internal_ref_cast(obj: &PyAny) -> &T {
         &*(obj as *const _ as *const T)
     }
+
+    #[allow(clippy::mut_from_ref)]
     unsafe fn internal_mut_cast(obj: &PyAny) -> &mut T {
         &mut *(obj as *const _ as *const T as *mut T)
     }
@@ -27,6 +33,11 @@ pub trait PyObjectLayout<T: PyTypeInfo> {
     unsafe fn py_drop(&mut self, _py: Python) {}
 }
 
+/// `T: PyObjectSizedLayout<U>` represents `T` is not a instance of
+/// [`PyVarObject`](https://docs.python.org/3.8/c-api/structures.html?highlight=pyvarobject#c.PyVarObject).
+/// , in addition that `T` is a concrete representaion of `U`.
+///
+/// `pyclass`es need this trait for their base class.
 pub trait PyObjectSizedLayout<T: PyTypeInfo>: PyObjectLayout<T> + Sized {}
 
 /// Our custom type flags

src/types/string.rs

@@ -207,7 +207,7 @@ mod test {
         let s = "Hello Python";
         let py_string = s.to_object(py);
 
-        let s2: &str = FromPyObject::extract(py_string.as_ref(py).into()).unwrap();
+        let s2: &str = FromPyObject::extract(py_string.as_ref(py)).unwrap();
         assert_eq!(s, s2);
     }
 

src/types/tuple.rs

@@ -119,7 +119,7 @@ impl<'a> Iterator for PyTupleIterator<'a> {
         if self.index < self.slice.len() {
             let item = self.slice[self.index].as_ref(self.py);
             self.index += 1;
-            Some(item.into())
+            Some(item)
         } else {
             None
         }

tests/test_inheritance.rs

@@ -91,7 +91,7 @@ struct InvalidSubClass2 {
 impl InvalidSubClass2 {
     #[new]
     fn new() -> PyClassInitializer<Self> {
-        PyClassInitializer::new()
+        PyClassInitializer::default()
     }
 }