Implement alloc::rc::{Rc,Weak,UniqueRc} with alloc::raw_rc types

Author: EFanZh

library/alloc/src/raw_rc/mod.rs

@@ -59,12 +59,14 @@
 //! - Converting `Option<Rc<T>>` to `Option<&T>` without checking for `None` values.
 //! - Converting `&[Rc<T>]` to `&[&T]` with zero cost.
 
-#![allow(dead_code)]
-
 use core::cell::UnsafeCell;
 use core::mem;
 use core::sync::atomic::Atomic;
 
+pub(crate) use crate::raw_rc::raw_rc::RawRc;
+pub(crate) use crate::raw_rc::raw_unique_rc::RawUniqueRc;
+pub(crate) use crate::raw_rc::raw_weak::RawWeak;
+
 mod raw_rc;
 mod raw_unique_rc;
 mod raw_weak;

library/alloc/src/raw_rc/raw_rc.rs

@@ -836,7 +836,7 @@ where
     T: ?Sized,
 {
     fn as_ref(&self) -> &T {
-        unsafe { self.weak.as_ptr().as_ref() }
+        self.as_ref()
     }
 }