Add rustc_do_not_implement_via_object

Author: compiler-errors

core/src/marker.rs

@@ -174,6 +174,7 @@ pub trait Sized {
 #[unstable(feature = "unsize", issue = "18598")]
 #[lang = "unsize"]
 #[rustc_deny_explicit_impl]
+#[cfg_attr(not(bootstrap), rustc_do_not_implement_via_object)]
 pub trait Unsize<T: ?Sized> {
     // Empty.
 }
@@ -855,6 +856,7 @@ impl<T: ?Sized> StructuralEq for PhantomData<T> {}
 )]
 #[lang = "discriminant_kind"]
 #[rustc_deny_explicit_impl]
+#[cfg_attr(not(bootstrap), rustc_do_not_implement_via_object)]
 pub trait DiscriminantKind {
     /// The type of the discriminant, which must satisfy the trait
     /// bounds required by `mem::Discriminant`.
@@ -960,6 +962,7 @@ marker_impls! {
 #[lang = "destruct"]
 #[rustc_on_unimplemented(message = "can't drop `{Self}`", append_const_msg)]
 #[rustc_deny_explicit_impl]
+#[cfg_attr(not(bootstrap), rustc_do_not_implement_via_object)]
 #[const_trait]
 pub trait Destruct {}
 
@@ -971,6 +974,7 @@ pub trait Destruct {}
 #[lang = "tuple_trait"]
 #[rustc_on_unimplemented(message = "`{Self}` is not a tuple")]
 #[rustc_deny_explicit_impl]
+#[cfg_attr(not(bootstrap), rustc_do_not_implement_via_object)]
 pub trait Tuple {}
 
 /// A marker for pointer-like types.

core/src/mem/transmutability.rs

@@ -7,6 +7,7 @@ use crate::marker::ConstParamTy;
 /// notwithstanding whatever safety checks you have asked the compiler to [`Assume`] are satisfied.
 #[unstable(feature = "transmutability", issue = "99571")]
 #[lang = "transmute_trait"]
+#[cfg_attr(not(bootstrap), rustc_do_not_implement_via_object)]
 pub unsafe trait BikeshedIntrinsicFrom<Src, Context, const ASSUME: Assume = { Assume::NOTHING }>
 where
     Src: ?Sized,

core/src/ptr/metadata.rs

@@ -51,6 +51,7 @@ use crate::hash::{Hash, Hasher};
 /// [`to_raw_parts`]: *const::to_raw_parts
 #[lang = "pointee_trait"]
 #[rustc_deny_explicit_impl]
+#[cfg_attr(not(bootstrap), rustc_do_not_implement_via_object)]
 pub trait Pointee {
     /// The type for metadata in pointers and references to `Self`.
     #[lang = "metadata_type"]