diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index 148b66d959e8a..df1150ec0b8ce 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -128,7 +128,7 @@ pub(crate) fn codegen_const_value<'tcx>(
     ty: Ty<'tcx>,
 ) -> CValue<'tcx> {
     let layout = fx.layout_of(ty);
-    assert!(!layout.is_unsized(), "sized const value");
+    assert!(layout.is_sized(), "unsized const value");
 
     if layout.is_zst() {
         return CValue::by_ref(crate::Pointer::dangling(layout.align.pref), layout);
diff --git a/compiler/rustc_codegen_cranelift/src/value_and_place.rs b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
index c3dfbd37279f9..c5bd574623df6 100644
--- a/compiler/rustc_codegen_cranelift/src/value_and_place.rs
+++ b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
@@ -19,7 +19,7 @@ fn codegen_field<'tcx>(
     };
 
     if let Some(extra) = extra {
-        if !field_layout.is_unsized() {
+        if field_layout.is_sized() {
             return simple(fx);
         }
         match field_layout.ty.kind() {
@@ -364,7 +364,7 @@ impl<'tcx> CPlace<'tcx> {
         fx: &mut FunctionCx<'_, '_, 'tcx>,
         layout: TyAndLayout<'tcx>,
     ) -> CPlace<'tcx> {
-        assert!(!layout.is_unsized());
+        assert!(layout.is_sized());
         if layout.size.bytes() == 0 {
             return CPlace {
                 inner: CPlaceInner::Addr(Pointer::dangling(layout.align.pref), None),
@@ -825,7 +825,7 @@ impl<'tcx> CPlace<'tcx> {
         fx: &FunctionCx<'_, '_, 'tcx>,
         variant: VariantIdx,
     ) -> Self {
-        assert!(!self.layout().is_unsized());
+        assert!(self.layout().is_sized());
         let layout = self.layout().for_variant(fx, variant);
         CPlace { inner: self.inner, layout }
     }
diff --git a/compiler/rustc_codegen_gcc/src/type_.rs b/compiler/rustc_codegen_gcc/src/type_.rs
index 862ed62c68b2a..bdf7318ce48c9 100644
--- a/compiler/rustc_codegen_gcc/src/type_.rs
+++ b/compiler/rustc_codegen_gcc/src/type_.rs
@@ -277,7 +277,7 @@ pub fn struct_fields<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, layout: TyAndLayout
         offset = target_offset + field.size;
         prev_effective_align = effective_field_align;
     }
-    if !layout.is_unsized() && field_count > 0 {
+    if layout.is_sized() && field_count > 0 {
         if offset > layout.size {
             bug!("layout: {:#?} stride: {:?} offset: {:?}", layout, layout.size, offset);
         }
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs b/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
index a40cfc8b23fb3..5cd0e1cb63ae1 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
@@ -72,7 +72,7 @@ pub(crate) fn fat_pointer_kind<'ll, 'tcx>(
         layout.is_unsized()
     );
 
-    if !layout.is_unsized() {
+    if layout.is_sized() {
         return None;
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/type_of.rs b/compiler/rustc_codegen_llvm/src/type_of.rs
index dc1165835e7ca..182adf8178571 100644
--- a/compiler/rustc_codegen_llvm/src/type_of.rs
+++ b/compiler/rustc_codegen_llvm/src/type_of.rs
@@ -140,7 +140,7 @@ fn struct_llfields<'a, 'tcx>(
         prev_effective_align = effective_field_align;
     }
     let padding_used = result.len() > field_count;
-    if !layout.is_unsized() && field_count > 0 {
+    if layout.is_sized() && field_count > 0 {
         if offset > layout.size {
             bug!("layout: {:#?} stride: {:?} offset: {:?}", layout, layout.size, offset);
         }
diff --git a/compiler/rustc_codegen_ssa/src/glue.rs b/compiler/rustc_codegen_ssa/src/glue.rs
index e6f402ef19d87..6015d48decae9 100644
--- a/compiler/rustc_codegen_ssa/src/glue.rs
+++ b/compiler/rustc_codegen_ssa/src/glue.rs
@@ -15,7 +15,7 @@ pub fn size_and_align_of_dst<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 ) -> (Bx::Value, Bx::Value) {
     let layout = bx.layout_of(t);
     debug!("size_and_align_of_dst(ty={}, info={:?}): layout: {:?}", t, info, layout);
-    if !layout.is_unsized() {
+    if layout.is_sized() {
         let size = bx.const_usize(layout.size.bytes());
         let align = bx.const_usize(layout.align.abi.bytes());
         return (size, align);
diff --git a/compiler/rustc_codegen_ssa/src/mir/place.rs b/compiler/rustc_codegen_ssa/src/mir/place.rs
index 8c72d6d1fbe36..908555385891d 100644
--- a/compiler/rustc_codegen_ssa/src/mir/place.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/place.rs
@@ -29,7 +29,7 @@ pub struct PlaceRef<'tcx, V> {
 
 impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
     pub fn new_sized(llval: V, layout: TyAndLayout<'tcx>) -> PlaceRef<'tcx, V> {
-        assert!(!layout.is_unsized());
+        assert!(layout.is_sized());
         PlaceRef { llval, llextra: None, layout, align: layout.align.abi }
     }
 
@@ -38,7 +38,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
         layout: TyAndLayout<'tcx>,
         align: Align,
     ) -> PlaceRef<'tcx, V> {
-        assert!(!layout.is_unsized());
+        assert!(layout.is_sized());
         PlaceRef { llval, llextra: None, layout, align }
     }
 
@@ -48,7 +48,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
         bx: &mut Bx,
         layout: TyAndLayout<'tcx>,
     ) -> Self {
-        assert!(!layout.is_unsized(), "tried to statically allocate unsized place");
+        assert!(layout.is_sized(), "tried to statically allocate unsized place");
         let tmp = bx.alloca(bx.cx().backend_type(layout), layout.align.abi);
         Self::new_sized(tmp, layout)
     }
@@ -145,7 +145,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
                 );
                 return simple();
             }
-            _ if !field.is_unsized() => return simple(),
+            _ if field.is_sized() => return simple(),
             ty::Slice(..) | ty::Str | ty::Foreign(..) => return simple(),
             ty::Adt(def, _) => {
                 if def.repr().packed() {
diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
index 1b1052fdf47a7..8f5e503d659da 100644
--- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -46,7 +46,7 @@ fn eval_body_using_ecx<'mir, 'tcx>(
         ecx.tcx.def_kind(cid.instance.def_id())
     );
     let layout = ecx.layout_of(body.bound_return_ty().subst(tcx, cid.instance.substs))?;
-    assert!(!layout.is_unsized());
+    assert!(layout.is_sized());
     let ret = ecx.allocate(layout, MemoryKind::Stack)?;
 
     trace!(
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index f7d64f6d4f48a..ab82268dde3ab 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -572,7 +572,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         metadata: &MemPlaceMeta<M::Provenance>,
         layout: &TyAndLayout<'tcx>,
     ) -> InterpResult<'tcx, Option<(Size, Align)>> {
-        if !layout.is_unsized() {
+        if layout.is_sized() {
             return Ok(Some((layout.size, layout.align.abi)));
         }
         match layout.ty.kind() {
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index b92a68788475f..e68456a1d731a 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -713,7 +713,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         rhs: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::Provenance>,
     ) -> InterpResult<'tcx, Scalar<M::Provenance>> {
         let layout = self.layout_of(lhs.layout.ty.builtin_deref(true).unwrap().ty)?;
-        assert!(!layout.is_unsized());
+        assert!(layout.is_sized());
 
         let get_bytes = |this: &InterpCx<'mir, 'tcx, M>,
                          op: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::Provenance>,
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index e5e015c1e1802..a529972db9d6f 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -683,7 +683,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // Use size and align of the type.
                 let ty = self.tcx.type_of(def_id);
                 let layout = self.tcx.layout_of(ParamEnv::empty().and(ty)).unwrap();
-                assert!(!layout.is_unsized());
+                assert!(layout.is_sized());
                 (layout.size, layout.align.abi, AllocKind::LiveData)
             }
             Some(GlobalAlloc::Memory(alloc)) => {
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index dd00678aa0cea..274917f09fe36 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -280,7 +280,7 @@ impl<'tcx, Prov: Provenance> OpTy<'tcx, Prov> {
         layout: TyAndLayout<'tcx>,
         cx: &impl HasDataLayout,
     ) -> InterpResult<'tcx, Self> {
-        assert!(!layout.is_unsized());
+        assert!(layout.is_sized());
         self.offset_with_meta(offset, MemPlaceMeta::None, layout, cx)
     }
 }
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index b0625b5f412e0..4d0125bf395d6 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -201,7 +201,7 @@ impl<'tcx, Prov: Provenance> MPlaceTy<'tcx, Prov> {
         layout: TyAndLayout<'tcx>,
         cx: &impl HasDataLayout,
     ) -> InterpResult<'tcx, Self> {
-        assert!(!layout.is_unsized());
+        assert!(layout.is_sized());
         self.offset_with_meta(offset, MemPlaceMeta::None, layout, cx)
     }
 
@@ -340,7 +340,7 @@ where
         &self,
         place: &MPlaceTy<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx, Option<AllocRef<'_, 'tcx, M::Provenance, M::AllocExtra>>> {
-        assert!(!place.layout.is_unsized());
+        assert!(place.layout.is_sized());
         assert!(!place.meta.has_meta());
         let size = place.layout.size;
         self.get_ptr_alloc(place.ptr, size, place.align)
@@ -351,7 +351,7 @@ where
         &mut self,
         place: &MPlaceTy<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx, Option<AllocRefMut<'_, 'tcx, M::Provenance, M::AllocExtra>>> {
-        assert!(!place.layout.is_unsized());
+        assert!(place.layout.is_sized());
         assert!(!place.meta.has_meta());
         let size = place.layout.size;
         self.get_ptr_alloc_mut(place.ptr, size, place.align)
@@ -485,7 +485,7 @@ where
         src: Immediate<M::Provenance>,
         dest: &PlaceTy<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx> {
-        assert!(!dest.layout.is_unsized(), "Cannot write unsized data");
+        assert!(dest.layout.is_sized(), "Cannot write unsized data");
         trace!("write_immediate: {:?} <- {:?}: {}", *dest, src, dest.layout.ty);
 
         // See if we can avoid an allocation. This is the counterpart to `read_immediate_raw`,
@@ -746,7 +746,7 @@ where
         layout: TyAndLayout<'tcx>,
         kind: MemoryKind<M::MemoryKind>,
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> {
-        assert!(!layout.is_unsized());
+        assert!(layout.is_sized());
         let ptr = self.allocate_ptr(layout.size, layout.align.abi, kind)?;
         Ok(MPlaceTy::from_aligned_ptr(ptr.into(), layout))
     }
diff --git a/compiler/rustc_const_eval/src/interpret/step.rs b/compiler/rustc_const_eval/src/interpret/step.rs
index c6e04cbfb6bf3..3c286fa61bec5 100644
--- a/compiler/rustc_const_eval/src/interpret/step.rs
+++ b/compiler/rustc_const_eval/src/interpret/step.rs
@@ -209,7 +209,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
             Repeat(ref operand, _) => {
                 let src = self.eval_operand(operand, None)?;
-                assert!(!src.layout.is_unsized());
+                assert!(src.layout.is_sized());
                 let dest = self.force_allocation(&dest)?;
                 let length = dest.len(self)?;
 
diff --git a/compiler/rustc_const_eval/src/interpret/traits.rs b/compiler/rustc_const_eval/src/interpret/traits.rs
index cab23b7241ffc..fa15d466ac125 100644
--- a/compiler/rustc_const_eval/src/interpret/traits.rs
+++ b/compiler/rustc_const_eval/src/interpret/traits.rs
@@ -53,7 +53,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ) -> InterpResult<'tcx, (Size, Align)> {
         let (ty, _trait_ref) = self.get_ptr_vtable(vtable)?;
         let layout = self.layout_of(ty)?;
-        assert!(!layout.is_unsized(), "there are no vtables for unsized types");
+        assert!(layout.is_sized(), "there are no vtables for unsized types");
         Ok((layout.size, layout.align.abi))
     }
 }
diff --git a/compiler/rustc_middle/src/ty/vtable.rs b/compiler/rustc_middle/src/ty/vtable.rs
index 5ca51c25a9ce1..6eae94511e4d6 100644
--- a/compiler/rustc_middle/src/ty/vtable.rs
+++ b/compiler/rustc_middle/src/ty/vtable.rs
@@ -66,7 +66,7 @@ pub(super) fn vtable_allocation_provider<'tcx>(
     let layout = tcx
         .layout_of(ty::ParamEnv::reveal_all().and(ty))
         .expect("failed to build vtable representation");
-    assert!(!layout.is_unsized(), "can't create a vtable for an unsized type");
+    assert!(layout.is_sized(), "can't create a vtable for an unsized type");
     let size = layout.size.bytes();
     let align = layout.align.abi.bytes();
 
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 4e4515888454b..4f30e8a0be03e 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -385,7 +385,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             // I don't know how return types can seem to be unsized but this happens in the
             // `type/type-unsatisfiable.rs` test.
             .filter(|ret_layout| {
-                !ret_layout.is_unsized() && ret_layout.size < Size::from_bytes(MAX_ALLOC_LIMIT)
+                ret_layout.is_sized() && ret_layout.size < Size::from_bytes(MAX_ALLOC_LIMIT)
             })
             .unwrap_or_else(|| ecx.layout_of(tcx.types.unit).unwrap());
 
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 479c4e577d4e3..163446c52e4c2 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -199,7 +199,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             // I don't know how return types can seem to be unsized but this happens in the
             // `type/type-unsatisfiable.rs` test.
             .filter(|ret_layout| {
-                !ret_layout.is_unsized() && ret_layout.size < Size::from_bytes(MAX_ALLOC_LIMIT)
+                ret_layout.is_sized() && ret_layout.size < Size::from_bytes(MAX_ALLOC_LIMIT)
             })
             .unwrap_or_else(|| ecx.layout_of(tcx.types.unit).unwrap());
 
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index 78afa2f25f8e1..af49d438a22cb 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -536,6 +536,14 @@ impl<'tcx> MissingStabilityAnnotations<'tcx> {
             return;
         }
 
+        // if the const impl is derived using the `derive_const` attribute,
+        // then it would be "stable" at least for the impl.
+        // We gate usages of it using `feature(const_trait_impl)` anyways
+        // so there is no unstable leakage
+        if self.tcx.is_builtin_derive(def_id.to_def_id()) {
+            return;
+        }
+
         let is_const = self.tcx.is_const_fn(def_id.to_def_id())
             || self.tcx.is_const_trait_impl_raw(def_id.to_def_id());
         let is_stable = self
diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index 423c57275333a..e7e419c9b4238 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -469,9 +469,11 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         }
 
                         // Replace `use foo::{ self };` with `use foo;`
+                        let self_span = source.ident.span;
                         source = module_path.pop().unwrap();
                         if rename.is_none() {
-                            ident = source.ident;
+                            // Keep the span of `self`, but the name of `foo`
+                            ident = Ident { name: source.ident.name, span: self_span };
                         }
                     }
                 } else {
diff --git a/compiler/rustc_target/src/abi/mod.rs b/compiler/rustc_target/src/abi/mod.rs
index 7171ca7bf8950..decbefc2f7c62 100644
--- a/compiler/rustc_target/src/abi/mod.rs
+++ b/compiler/rustc_target/src/abi/mod.rs
@@ -1083,6 +1083,11 @@ impl Abi {
         }
     }
 
+    #[inline]
+    pub fn is_sized(&self) -> bool {
+        !self.is_unsized()
+    }
+
     /// Returns `true` if this is a single signed integer scalar
     #[inline]
     pub fn is_signed(&self) -> bool {
@@ -1490,6 +1495,11 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
         self.abi.is_unsized()
     }
 
+    #[inline]
+    pub fn is_sized(&self) -> bool {
+        self.abi.is_sized()
+    }
+
     /// Returns `true` if the type is a ZST and not unsized.
     pub fn is_zst(&self) -> bool {
         match self.abi {
diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs
index 52ba0eee97cd5..b59be0a0ea794 100644
--- a/compiler/rustc_ty_utils/src/layout.rs
+++ b/compiler/rustc_ty_utils/src/layout.rs
@@ -668,7 +668,7 @@ fn layout_of_uncached<'tcx>(
                 let mut abi = Abi::Aggregate { sized: true };
                 let index = VariantIdx::new(0);
                 for field in &variants[index] {
-                    assert!(!field.is_unsized());
+                    assert!(field.is_sized());
                     align = align.max(field.align);
 
                     // If all non-ZST fields have the same ABI, forward this ABI
diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs
index f0fa2e1d2c190..5db5cbfc3dfdd 100644
--- a/library/core/src/cmp.rs
+++ b/library/core/src/cmp.rs
@@ -24,6 +24,7 @@
 
 use crate::const_closure::ConstFnMutClosure;
 use crate::marker::Destruct;
+#[cfg(bootstrap)]
 use crate::marker::StructuralPartialEq;
 
 use self::Ordering::*;
@@ -331,6 +332,7 @@ pub struct AssertParamIsEq<T: Eq + ?Sized> {
 /// assert_eq!(Ordering::Greater, result);
 /// ```
 #[derive(Clone, Copy, Eq, Debug, Hash)]
+#[cfg_attr(not(bootstrap), derive_const(PartialOrd, Ord, PartialEq))]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[repr(i8)]
 pub enum Ordering {
@@ -877,10 +879,12 @@ pub macro Ord($item:item) {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg(bootstrap)]
 impl StructuralPartialEq for Ordering {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+#[cfg(bootstrap)]
 impl const PartialEq for Ordering {
     #[inline]
     fn eq(&self, other: &Self) -> bool {
@@ -890,6 +894,7 @@ impl const PartialEq for Ordering {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+#[cfg(bootstrap)]
 impl const Ord for Ordering {
     #[inline]
     fn cmp(&self, other: &Ordering) -> Ordering {
@@ -899,6 +904,7 @@ impl const Ord for Ordering {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+#[cfg(bootstrap)]
 impl const PartialOrd for Ordering {
     #[inline]
     fn partial_cmp(&self, other: &Ordering) -> Option<Ordering> {
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 5dc7427bee003..8425354837841 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -185,6 +185,7 @@
 #![feature(const_refs_to_cell)]
 #![feature(decl_macro)]
 #![feature(deprecated_suggestion)]
+#![cfg_attr(not(bootstrap), feature(derive_const))]
 #![feature(doc_cfg)]
 #![feature(doc_notable_trait)]
 #![feature(rustdoc_internals)]
diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs
index 565c38d222a2c..fd6fe46bf50a8 100644
--- a/library/core/src/ptr/mod.rs
+++ b/library/core/src/ptr/mod.rs
@@ -35,7 +35,8 @@
 //!   be used for inter-thread synchronization.
 //! * The result of casting a reference to a pointer is valid for as long as the
 //!   underlying object is live and no reference (just raw pointers) is used to
-//!   access the same memory.
+//!   access the same memory. That is, reference and pointer accesses cannot be
+//!   interleaved.
 //!
 //! These axioms, along with careful use of [`offset`] for pointer arithmetic,
 //! are enough to correctly implement many useful things in unsafe code. Stronger guarantees
@@ -64,7 +65,6 @@
 //! separate allocated object), heap allocations (each allocation created by the global allocator is
 //! a separate allocated object), and `static` variables.
 //!
-//!
 //! # Strict Provenance
 //!
 //! **The following text is non-normative, insufficiently formal, and is an extremely strict
diff --git a/src/test/ui/use/use-crate-self.rs b/src/test/ui/use/use-crate-self.rs
new file mode 100644
index 0000000000000..65ab948147cdc
--- /dev/null
+++ b/src/test/ui/use/use-crate-self.rs
@@ -0,0 +1,4 @@
+use crate::{self};
+        //~^ ERROR crate root imports need to be explicitly named: `use crate as name;`
+
+fn main() {}
diff --git a/src/test/ui/use/use-crate-self.stderr b/src/test/ui/use/use-crate-self.stderr
new file mode 100644
index 0000000000000..dd4036bfff475
--- /dev/null
+++ b/src/test/ui/use/use-crate-self.stderr
@@ -0,0 +1,8 @@
+error: crate root imports need to be explicitly named: `use crate as name;`
+  --> $DIR/use-crate-self.rs:1:13
+   |
+LL | use crate::{self};
+   |             ^^^^
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/src/stacked_borrows/mod.rs b/src/tools/miri/src/stacked_borrows/mod.rs
index 7f18e5dbae052..9ce02a02ec408 100644
--- a/src/tools/miri/src/stacked_borrows/mod.rs
+++ b/src/tools/miri/src/stacked_borrows/mod.rs
@@ -1053,7 +1053,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 // pointers we need to retag, so we can stop recursion early.
                 // This optimization is crucial for ZSTs, because they can contain way more fields
                 // than we can ever visit.
-                if !place.layout.is_unsized() && place.layout.size < self.ecx.pointer_size() {
+                if place.layout.is_sized() && place.layout.size < self.ecx.pointer_size() {
                     return Ok(());
                 }
 
diff --git a/triagebot.toml b/triagebot.toml
index 8efd9af41a42d..985e065652d62 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -182,6 +182,7 @@ trigger_files = [
     "x.ps1",
     "src/bootstrap",
     "src/tools/rust-installer",
+    "src/tools/x",
     "configure",
     "Cargo.toml",
     "Cargo.lock",
@@ -583,3 +584,4 @@ fallback = [
 "/src/tools/rustdoc-js" =                    ["rustdoc"]
 "/src/tools/rustdoc-themes" =                ["rustdoc"]
 "/src/tools/tidy" =                          ["bootstrap"]
+"/src/tools/x" =                             ["bootstrap"]