introduce `Bound::as_borrowed`

src/instance.rs

@@ -197,6 +197,15 @@ impl<'py, T> Bound<'py, T> {
         self.into_non_null().as_ptr()
     }
 
+    /// Casts this `Bound<T>` to a `Borrowed<T>` smart pointer.
+    pub fn as_borrowed<'a>(&'a self) -> Borrowed<'a, 'py, T> {
+        Borrowed(
+            unsafe { NonNull::new_unchecked(self.as_ptr()) },
+            PhantomData,
+            self.py(),
+        )
+    }
+
     /// Casts this `Bound<T>` as the corresponding "GIL Ref" type.
     ///
     /// This is a helper to be used for migration from the deprecated "GIL Refs" API.
@@ -300,11 +309,7 @@ impl<'a, 'py> Borrowed<'a, 'py, PyAny> {
 impl<'a, 'py, T> From<&'a Bound<'py, T>> for Borrowed<'a, 'py, T> {
     /// Create borrow on a Bound
     fn from(instance: &'a Bound<'py, T>) -> Self {
-        Self(
-            unsafe { NonNull::new_unchecked(instance.as_ptr()) },
-            PhantomData,
-            instance.py(),
-        )
+        instance.as_borrowed()
     }
 }
 

src/types/bytearray.rs

@@ -400,16 +400,16 @@ impl<'py> PyByteArrayMethods<'py> for Bound<'py, PyByteArray> {
     }
 
     fn data(&self) -> *mut u8 {
-        Borrowed::from(self).data()
+        self.as_borrowed().data()
     }
 
     unsafe fn as_bytes(&self) -> &[u8] {
-        Borrowed::from(self).as_bytes()
+        self.as_borrowed().as_bytes()
     }
 
     #[allow(clippy::mut_from_ref)]
     unsafe fn as_bytes_mut(&self) -> &mut [u8] {
-        Borrowed::from(self).as_bytes_mut()
+        self.as_borrowed().as_bytes_mut()
     }
 
     fn to_vec(&self) -> Vec<u8> {

src/types/bytes.rs

@@ -107,7 +107,7 @@ pub trait PyBytesMethods<'py> {
 impl<'py> PyBytesMethods<'py> for Bound<'py, PyBytes> {
     #[inline]
     fn as_bytes(&self) -> &[u8] {
-        Borrowed::from(self).as_bytes()
+        self.as_borrowed().as_bytes()
     }
 }
 

src/types/string.rs

@@ -280,20 +280,20 @@ pub trait PyStringMethods<'py> {
 impl<'py> PyStringMethods<'py> for Bound<'py, PyString> {
     #[cfg(any(Py_3_10, not(Py_LIMITED_API)))]
     fn to_str(&self) -> PyResult<&str> {
-        Borrowed::from(self).to_str()
+        self.as_borrowed().to_str()
     }
 
     fn to_cow(&self) -> PyResult<Cow<'_, str>> {
-        Borrowed::from(self).to_cow()
+        self.as_borrowed().to_cow()
     }
 
     fn to_string_lossy(&self) -> Cow<'_, str> {
-        Borrowed::from(self).to_string_lossy()
+        self.as_borrowed().to_string_lossy()
     }
 
     #[cfg(not(Py_LIMITED_API))]
     unsafe fn data(&self) -> PyResult<PyStringData<'_>> {
-        Borrowed::from(self).data()
+        self.as_borrowed().data()
     }
 }