(not to be included in commit message) do not impl PinCoerceUnsized

Author: dingxiangfei2009

rust/kernel/lib.rs

@@ -13,10 +13,7 @@
 
 #![no_std]
 #![feature(arbitrary_self_types)]
-#![cfg_attr(
-    CONFIG_RUST_COERCE_POINTEE,
-    feature(derive_coerce_pointee, pin_coerce_unsized_trait)
-)]
+#![cfg_attr(CONFIG_RUST_COERCE_POINTEE, feature(derive_coerce_pointee))]
 #![cfg_attr(
     not(CONFIG_RUST_COERCE_POINTEE),
     feature(coerce_unsized, dispatch_from_dyn, unsize)

rust/kernel/list/arc.rs

@@ -462,13 +462,6 @@ where
 {
 }
 
-/// `ListArc` is well-behaved so that its dereferencing operation does not mutate.
-#[cfg(CONFIG_RUST_COERCE_POINTEE)]
-unsafe impl<T: ?Sized + ListArcSafe<ID>, const ID: u64> core::pin::PinCoerceUnsized
-    for ListArc<T, ID>
-{
-}
-
 /// A utility for tracking whether a [`ListArc`] exists using an atomic.
 ///
 /// # Invariant