From 7e64f29534c21bee76775d73f44c595965e97a3d Mon Sep 17 00:00:00 2001
From: Alex Touchet <alextouchet@outlook.com>
Date: Mon, 15 Jan 2024 13:57:29 -0800
Subject: [PATCH 01/12] Update Readme

---
 README.md | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index da9e3556b4cac..6d6383351caf7 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,7 @@ If you wish to _contribute_ to the compiler, you should read
 <summary>Table of Contents</summary>
 
 - [Quick Start](#quick-start)
+- [Installing from Source](#installing-from-source)
 - [Getting Help](#getting-help)
 - [Contributing](#contributing)
 - [License](#license)
@@ -29,9 +30,10 @@ Read ["Installation"] from [The Book].
 ["Installation"]: https://doc.rust-lang.org/book/ch01-01-installation.html
 [The Book]: https://doc.rust-lang.org/book/index.html
 
-## Installing from source
+## Installing from Source
 
-If you really want to install from source (though this is not recommended), see [INSTALL.md](INSTALL.md).
+If you really want to install from source (though this is not recommended), see
+[INSTALL.md](INSTALL.md).
 
 ## Getting Help
 

From aa72e549cf779f82170203f70cc519fbbbfaa98b Mon Sep 17 00:00:00 2001
From: Scott McMurray <scottmcm@users.noreply.github.com>
Date: Tue, 16 Jan 2024 21:33:43 -0800
Subject: [PATCH 02/12] Un-hide `iter::repeat_n`

---
 library/core/src/iter/sources/repeat_n.rs | 2 --
 1 file changed, 2 deletions(-)

diff --git a/library/core/src/iter/sources/repeat_n.rs b/library/core/src/iter/sources/repeat_n.rs
index 0b0445850bf52..db2f8b7ac283f 100644
--- a/library/core/src/iter/sources/repeat_n.rs
+++ b/library/core/src/iter/sources/repeat_n.rs
@@ -59,7 +59,6 @@ use crate::num::NonZeroUsize;
 /// ```
 #[inline]
 #[unstable(feature = "iter_repeat_n", issue = "104434")]
-#[doc(hidden)] // waiting on ACP#120 to decide whether to expose publicly
 pub fn repeat_n<T: Clone>(element: T, count: usize) -> RepeatN<T> {
     let mut element = ManuallyDrop::new(element);
 
@@ -79,7 +78,6 @@ pub fn repeat_n<T: Clone>(element: T, count: usize) -> RepeatN<T> {
 /// See its documentation for more.
 #[derive(Clone, Debug)]
 #[unstable(feature = "iter_repeat_n", issue = "104434")]
-#[doc(hidden)] // waiting on ACP#120 to decide whether to expose publicly
 pub struct RepeatN<A> {
     count: usize,
     // Invariant: has been dropped iff count == 0.

From 06a9dbe5e80c55b20f79aac6d32ad7a81cf544d2 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Fri, 19 Jan 2024 09:42:30 +0000
Subject: [PATCH 03/12] Fix a soundness bug in `with_tables`.

We were able to uplift any value from `Tables` to `'static`, which is unsound.
---
 compiler/rustc_smir/src/rustc_internal/mod.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_smir/src/rustc_internal/mod.rs b/compiler/rustc_smir/src/rustc_internal/mod.rs
index b99640d2f2d68..cd4ad724b00af 100644
--- a/compiler/rustc_smir/src/rustc_internal/mod.rs
+++ b/compiler/rustc_smir/src/rustc_internal/mod.rs
@@ -162,12 +162,12 @@ where
 
 /// Loads the current context and calls a function with it.
 /// Do not nest these, as that will ICE.
-pub(crate) fn with_tables<'tcx, R>(f: impl FnOnce(&mut Tables<'tcx>) -> R) -> R {
+pub(crate) fn with_tables<R>(f: impl for<'tcx> FnOnce(&mut Tables<'tcx>) -> R) -> R {
     assert!(TLV.is_set());
     TLV.with(|tlv| {
         let ptr = tlv.get();
         assert!(!ptr.is_null());
-        let wrapper = ptr as *const TablesWrapper<'tcx>;
+        let wrapper = ptr as *const TablesWrapper<'_>;
         let mut tables = unsafe { (*wrapper).0.borrow_mut() };
         f(&mut *tables)
     })

From 61361c16aac632367c0137ce74f6d3248edd8932 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Fri, 19 Jan 2024 09:42:51 +0000
Subject: [PATCH 04/12] Fix `Stable` trait and its impls to work with the new
 `with_tables`

---
 compiler/rustc_arena/src/lib.rs               |  13 ++
 compiler/rustc_middle/src/mir/consts.rs       |   4 +-
 compiler/rustc_middle/src/ty/context.rs       |  23 +++-
 .../rustc_smir/src/rustc_smir/convert/abi.rs  |  34 ++---
 .../src/rustc_smir/convert/error.rs           |   4 +-
 .../rustc_smir/src/rustc_smir/convert/mir.rs  |  82 ++++++------
 .../rustc_smir/src/rustc_smir/convert/mod.rs  |  12 +-
 .../rustc_smir/src/rustc_smir/convert/ty.rs   | 117 +++++++++---------
 compiler/rustc_smir/src/rustc_smir/mod.rs     |  16 +--
 9 files changed, 173 insertions(+), 132 deletions(-)

diff --git a/compiler/rustc_arena/src/lib.rs b/compiler/rustc_arena/src/lib.rs
index 621516af9c053..90ddeec4bc7a4 100644
--- a/compiler/rustc_arena/src/lib.rs
+++ b/compiler/rustc_arena/src/lib.rs
@@ -484,6 +484,19 @@ impl DroplessArena {
         }
     }
 
+    /// Used by `Lift` to check whether this slice is allocated
+    /// in this arena.
+    #[inline]
+    pub fn contains_slice<T>(&self, slice: &[T]) -> bool {
+        for chunk in self.chunks.borrow_mut().iter_mut() {
+            let ptr = slice.as_ptr().cast::<u8>().cast_mut();
+            if chunk.start() <= ptr && chunk.end() >= ptr {
+                return true;
+            }
+        }
+        false
+    }
+
     /// Allocates a string slice that is copied into the `DroplessArena`, returning a
     /// reference to it. Will panic if passed an empty string.
     ///
diff --git a/compiler/rustc_middle/src/mir/consts.rs b/compiler/rustc_middle/src/mir/consts.rs
index 2c38f998c9590..9731d86fb17c2 100644
--- a/compiler/rustc_middle/src/mir/consts.rs
+++ b/compiler/rustc_middle/src/mir/consts.rs
@@ -195,7 +195,7 @@ impl<'tcx> ConstValue<'tcx> {
 /// Constants
 
 #[derive(Clone, Copy, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable, Debug)]
-#[derive(TypeFoldable, TypeVisitable)]
+#[derive(TypeFoldable, TypeVisitable, Lift)]
 pub enum Const<'tcx> {
     /// This constant came from the type system.
     ///
@@ -456,7 +456,7 @@ impl<'tcx> Const<'tcx> {
 
 /// An unevaluated (potentially generic) constant used in MIR.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
-#[derive(Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(Hash, HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct UnevaluatedConst<'tcx> {
     pub def: DefId,
     pub args: GenericArgsRef<'tcx>,
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 6807eacb7f177..8fa60a3763ea8 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1416,6 +1416,7 @@ nop_lift! {const_; Const<'a> => Const<'tcx>}
 nop_lift! {const_allocation; ConstAllocation<'a> => ConstAllocation<'tcx>}
 nop_lift! {predicate; Predicate<'a> => Predicate<'tcx>}
 nop_lift! {predicate; Clause<'a> => Clause<'tcx>}
+nop_lift! {layout; Layout<'a> => Layout<'tcx>}
 
 nop_list_lift! {type_lists; Ty<'a> => Ty<'tcx>}
 nop_list_lift! {poly_existential_predicates; PolyExistentialPredicate<'a> => PolyExistentialPredicate<'tcx>}
@@ -1424,8 +1425,28 @@ nop_list_lift! {bound_variable_kinds; ty::BoundVariableKind => ty::BoundVariable
 // This is the impl for `&'a GenericArgs<'a>`.
 nop_list_lift! {args; GenericArg<'a> => GenericArg<'tcx>}
 
+macro_rules! nop_slice_lift {
+    ($ty:ty => $lifted:ty) => {
+        impl<'a, 'tcx> Lift<'tcx> for &'a [$ty] {
+            type Lifted = &'tcx [$lifted];
+            fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
+                if self.is_empty() {
+                    return Some(&[]);
+                }
+                tcx.interners
+                    .arena
+                    .dropless
+                    .contains_slice(self)
+                    .then(|| unsafe { mem::transmute(self) })
+            }
+        }
+    };
+}
+
+nop_slice_lift! {ty::ValTree<'a> => ty::ValTree<'tcx>}
+
 TrivialLiftImpls! {
-    ImplPolarity,
+    ImplPolarity, Promoted
 }
 
 macro_rules! sty_debug_print {
diff --git a/compiler/rustc_smir/src/rustc_smir/convert/abi.rs b/compiler/rustc_smir/src/rustc_smir/convert/abi.rs
index 632e97b32f520..68b564741dc1f 100644
--- a/compiler/rustc_smir/src/rustc_smir/convert/abi.rs
+++ b/compiler/rustc_smir/src/rustc_smir/convert/abi.rs
@@ -14,7 +14,7 @@ use stable_mir::{opaque, Opaque};
 
 impl<'tcx> Stable<'tcx> for rustc_target::abi::VariantIdx {
     type T = VariantIdx;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         VariantIdx::to_val(self.as_usize())
     }
 }
@@ -22,7 +22,7 @@ impl<'tcx> Stable<'tcx> for rustc_target::abi::VariantIdx {
 impl<'tcx> Stable<'tcx> for rustc_abi::Endian {
     type T = stable_mir::target::Endian;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         match self {
             rustc_abi::Endian::Little => stable_mir::target::Endian::Little,
             rustc_abi::Endian::Big => stable_mir::target::Endian::Big,
@@ -33,7 +33,7 @@ impl<'tcx> Stable<'tcx> for rustc_abi::Endian {
 impl<'tcx> Stable<'tcx> for rustc_target::abi::TyAndLayout<'tcx, ty::Ty<'tcx>> {
     type T = TyAndLayout;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         TyAndLayout { ty: self.ty.stable(tables), layout: self.layout.stable(tables) }
     }
 }
@@ -41,8 +41,8 @@ impl<'tcx> Stable<'tcx> for rustc_target::abi::TyAndLayout<'tcx, ty::Ty<'tcx>> {
 impl<'tcx> Stable<'tcx> for rustc_target::abi::Layout<'tcx> {
     type T = Layout;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.layout_id(*self)
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
+        tables.layout_id(tables.tcx.lift(*self).unwrap())
     }
 }
 
@@ -51,7 +51,7 @@ impl<'tcx> Stable<'tcx>
 {
     type T = LayoutShape;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         LayoutShape {
             fields: self.fields.stable(tables),
             variants: self.variants.stable(tables),
@@ -65,7 +65,7 @@ impl<'tcx> Stable<'tcx>
 impl<'tcx> Stable<'tcx> for rustc_target::abi::call::FnAbi<'tcx, ty::Ty<'tcx>> {
     type T = FnAbi;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         assert!(self.args.len() >= self.fixed_count as usize);
         assert!(!self.c_variadic || matches!(self.conv, Conv::C));
         FnAbi {
@@ -81,7 +81,7 @@ impl<'tcx> Stable<'tcx> for rustc_target::abi::call::FnAbi<'tcx, ty::Ty<'tcx>> {
 impl<'tcx> Stable<'tcx> for rustc_target::abi::call::ArgAbi<'tcx, ty::Ty<'tcx>> {
     type T = ArgAbi;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         ArgAbi {
             ty: self.layout.ty.stable(tables),
             layout: self.layout.layout.stable(tables),
@@ -93,7 +93,7 @@ impl<'tcx> Stable<'tcx> for rustc_target::abi::call::ArgAbi<'tcx, ty::Ty<'tcx>>
 impl<'tcx> Stable<'tcx> for rustc_target::abi::call::Conv {
     type T = CallConvention;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         match self {
             Conv::C => CallConvention::C,
             Conv::Rust => CallConvention::Rust,
@@ -122,7 +122,7 @@ impl<'tcx> Stable<'tcx> for rustc_target::abi::call::Conv {
 impl<'tcx> Stable<'tcx> for rustc_target::abi::call::PassMode {
     type T = PassMode;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         match self {
             rustc_target::abi::call::PassMode::Ignore => PassMode::Ignore,
             rustc_target::abi::call::PassMode::Direct(attr) => PassMode::Direct(opaque(attr)),
@@ -146,7 +146,7 @@ impl<'tcx> Stable<'tcx> for rustc_target::abi::call::PassMode {
 impl<'tcx> Stable<'tcx> for rustc_abi::FieldsShape<rustc_target::abi::FieldIdx> {
     type T = FieldsShape;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             rustc_abi::FieldsShape::Primitive => FieldsShape::Primitive,
             rustc_abi::FieldsShape::Union(count) => FieldsShape::Union(*count),
@@ -165,7 +165,7 @@ impl<'tcx> Stable<'tcx>
 {
     type T = VariantsShape;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             rustc_abi::Variants::Single { index } => {
                 VariantsShape::Single { index: index.stable(tables) }
@@ -185,7 +185,7 @@ impl<'tcx> Stable<'tcx>
 impl<'tcx> Stable<'tcx> for rustc_abi::TagEncoding<rustc_target::abi::VariantIdx> {
     type T = TagEncoding;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             rustc_abi::TagEncoding::Direct => TagEncoding::Direct,
             rustc_abi::TagEncoding::Niche { untagged_variant, niche_variants, niche_start } => {
@@ -202,7 +202,7 @@ impl<'tcx> Stable<'tcx> for rustc_abi::TagEncoding<rustc_target::abi::VariantIdx
 impl<'tcx> Stable<'tcx> for rustc_abi::Abi {
     type T = ValueAbi;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match *self {
             rustc_abi::Abi::Uninhabited => ValueAbi::Uninhabited,
             rustc_abi::Abi::Scalar(scalar) => ValueAbi::Scalar(scalar.stable(tables)),
@@ -220,7 +220,7 @@ impl<'tcx> Stable<'tcx> for rustc_abi::Abi {
 impl<'tcx> Stable<'tcx> for rustc_abi::Size {
     type T = Size;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         self.bytes_usize()
     }
 }
@@ -228,7 +228,7 @@ impl<'tcx> Stable<'tcx> for rustc_abi::Size {
 impl<'tcx> Stable<'tcx> for rustc_abi::Align {
     type T = Align;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         self.bytes()
     }
 }
@@ -236,7 +236,7 @@ impl<'tcx> Stable<'tcx> for rustc_abi::Align {
 impl<'tcx> Stable<'tcx> for rustc_abi::Scalar {
     type T = Opaque;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         opaque(self)
     }
 }
diff --git a/compiler/rustc_smir/src/rustc_smir/convert/error.rs b/compiler/rustc_smir/src/rustc_smir/convert/error.rs
index 6c582b799f867..8298450f741fb 100644
--- a/compiler/rustc_smir/src/rustc_smir/convert/error.rs
+++ b/compiler/rustc_smir/src/rustc_smir/convert/error.rs
@@ -8,7 +8,7 @@ use rustc_middle::ty::layout::LayoutError;
 impl<'tcx> Stable<'tcx> for LayoutError<'tcx> {
     type T = stable_mir::Error;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         stable_mir::Error::new(format!("{self:?}"))
     }
 }
@@ -16,7 +16,7 @@ impl<'tcx> Stable<'tcx> for LayoutError<'tcx> {
 impl<'tcx> Stable<'tcx> for AllocError {
     type T = stable_mir::Error;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         stable_mir::Error::new(format!("{self:?}"))
     }
 }
diff --git a/compiler/rustc_smir/src/rustc_smir/convert/mir.rs b/compiler/rustc_smir/src/rustc_smir/convert/mir.rs
index 2f3d9d69b8589..e433460e2ad9d 100644
--- a/compiler/rustc_smir/src/rustc_smir/convert/mir.rs
+++ b/compiler/rustc_smir/src/rustc_smir/convert/mir.rs
@@ -13,7 +13,7 @@ use crate::rustc_smir::{alloc, Stable, Tables};
 impl<'tcx> Stable<'tcx> for mir::Body<'tcx> {
     type T = stable_mir::mir::Body;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         stable_mir::mir::Body::new(
             self.basic_blocks
                 .iter()
@@ -44,7 +44,7 @@ impl<'tcx> Stable<'tcx> for mir::Body<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::VarDebugInfo<'tcx> {
     type T = stable_mir::mir::VarDebugInfo;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         stable_mir::mir::VarDebugInfo {
             name: self.name.to_string(),
             source_info: self.source_info.stable(tables),
@@ -57,21 +57,21 @@ impl<'tcx> Stable<'tcx> for mir::VarDebugInfo<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::Statement<'tcx> {
     type T = stable_mir::mir::Statement;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         Statement { kind: self.kind.stable(tables), span: self.source_info.span.stable(tables) }
     }
 }
 
 impl<'tcx> Stable<'tcx> for mir::SourceInfo {
     type T = stable_mir::mir::SourceInfo;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         stable_mir::mir::SourceInfo { span: self.span.stable(tables), scope: self.scope.into() }
     }
 }
 
 impl<'tcx> Stable<'tcx> for mir::VarDebugInfoFragment<'tcx> {
     type T = stable_mir::mir::VarDebugInfoFragment;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         VarDebugInfoFragment {
             ty: self.ty.stable(tables),
             projection: self.projection.iter().map(|e| e.stable(tables)).collect(),
@@ -81,7 +81,7 @@ impl<'tcx> Stable<'tcx> for mir::VarDebugInfoFragment<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::VarDebugInfoContents<'tcx> {
     type T = stable_mir::mir::VarDebugInfoContents;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             mir::VarDebugInfoContents::Place(place) => {
                 stable_mir::mir::VarDebugInfoContents::Place(place.stable(tables))
@@ -100,7 +100,7 @@ impl<'tcx> Stable<'tcx> for mir::VarDebugInfoContents<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::StatementKind<'tcx> {
     type T = stable_mir::mir::StatementKind;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             mir::StatementKind::Assign(assign) => stable_mir::mir::StatementKind::Assign(
                 assign.0.stable(tables),
@@ -158,7 +158,7 @@ impl<'tcx> Stable<'tcx> for mir::StatementKind<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::Rvalue<'tcx> {
     type T = stable_mir::mir::Rvalue;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::Rvalue::*;
         match self {
             Use(op) => stable_mir::mir::Rvalue::Use(op.stable(tables)),
@@ -214,7 +214,7 @@ impl<'tcx> Stable<'tcx> for mir::Rvalue<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::Mutability {
     type T = stable_mir::mir::Mutability;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_hir::Mutability::*;
         match *self {
             Not => stable_mir::mir::Mutability::Not,
@@ -225,7 +225,7 @@ impl<'tcx> Stable<'tcx> for mir::Mutability {
 
 impl<'tcx> Stable<'tcx> for mir::BorrowKind {
     type T = stable_mir::mir::BorrowKind;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::BorrowKind::*;
         match *self {
             Shared => stable_mir::mir::BorrowKind::Shared,
@@ -237,7 +237,7 @@ impl<'tcx> Stable<'tcx> for mir::BorrowKind {
 
 impl<'tcx> Stable<'tcx> for mir::MutBorrowKind {
     type T = stable_mir::mir::MutBorrowKind;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::MutBorrowKind::*;
         match *self {
             Default => stable_mir::mir::MutBorrowKind::Default,
@@ -249,7 +249,7 @@ impl<'tcx> Stable<'tcx> for mir::MutBorrowKind {
 
 impl<'tcx> Stable<'tcx> for mir::NullOp<'tcx> {
     type T = stable_mir::mir::NullOp;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::NullOp::*;
         match self {
             SizeOf => stable_mir::mir::NullOp::SizeOf,
@@ -263,7 +263,7 @@ impl<'tcx> Stable<'tcx> for mir::NullOp<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::CastKind {
     type T = stable_mir::mir::CastKind;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::CastKind::*;
         match self {
             PointerExposeAddress => stable_mir::mir::CastKind::PointerExposeAddress,
@@ -283,7 +283,7 @@ impl<'tcx> Stable<'tcx> for mir::CastKind {
 
 impl<'tcx> Stable<'tcx> for mir::FakeReadCause {
     type T = stable_mir::mir::FakeReadCause;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::FakeReadCause::*;
         match self {
             ForMatchGuard => stable_mir::mir::FakeReadCause::ForMatchGuard,
@@ -299,7 +299,7 @@ impl<'tcx> Stable<'tcx> for mir::FakeReadCause {
 
 impl<'tcx> Stable<'tcx> for mir::Operand<'tcx> {
     type T = stable_mir::mir::Operand;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::Operand::*;
         match self {
             Copy(place) => stable_mir::mir::Operand::Copy(place.stable(tables)),
@@ -312,7 +312,7 @@ impl<'tcx> Stable<'tcx> for mir::Operand<'tcx> {
 impl<'tcx> Stable<'tcx> for mir::ConstOperand<'tcx> {
     type T = stable_mir::mir::Constant;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         stable_mir::mir::Constant {
             span: self.span.stable(tables),
             user_ty: self.user_ty.map(|u| u.as_usize()).or(None),
@@ -323,7 +323,7 @@ impl<'tcx> Stable<'tcx> for mir::ConstOperand<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::Place<'tcx> {
     type T = stable_mir::mir::Place;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         stable_mir::mir::Place {
             local: self.local.as_usize(),
             projection: self.projection.iter().map(|e| e.stable(tables)).collect(),
@@ -333,7 +333,7 @@ impl<'tcx> Stable<'tcx> for mir::Place<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::PlaceElem<'tcx> {
     type T = stable_mir::mir::ProjectionElem;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::ProjectionElem::*;
         match self {
             Deref => stable_mir::mir::ProjectionElem::Deref,
@@ -368,21 +368,21 @@ impl<'tcx> Stable<'tcx> for mir::PlaceElem<'tcx> {
 impl<'tcx> Stable<'tcx> for mir::UserTypeProjection {
     type T = stable_mir::mir::UserTypeProjection;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         UserTypeProjection { base: self.base.as_usize(), projection: opaque(&self.projs) }
     }
 }
 
 impl<'tcx> Stable<'tcx> for mir::Local {
     type T = stable_mir::mir::Local;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         self.as_usize()
     }
 }
 
 impl<'tcx> Stable<'tcx> for mir::RetagKind {
     type T = stable_mir::mir::RetagKind;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::RetagKind;
         match self {
             RetagKind::FnEntry => stable_mir::mir::RetagKind::FnEntry,
@@ -395,7 +395,7 @@ impl<'tcx> Stable<'tcx> for mir::RetagKind {
 
 impl<'tcx> Stable<'tcx> for mir::UnwindAction {
     type T = stable_mir::mir::UnwindAction;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::UnwindAction;
         match self {
             UnwindAction::Continue => stable_mir::mir::UnwindAction::Continue,
@@ -409,7 +409,7 @@ impl<'tcx> Stable<'tcx> for mir::UnwindAction {
 impl<'tcx> Stable<'tcx> for mir::NonDivergingIntrinsic<'tcx> {
     type T = stable_mir::mir::NonDivergingIntrinsic;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::NonDivergingIntrinsic;
         use stable_mir::mir::CopyNonOverlapping;
         match self {
@@ -429,7 +429,7 @@ impl<'tcx> Stable<'tcx> for mir::NonDivergingIntrinsic<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::AssertMessage<'tcx> {
     type T = stable_mir::mir::AssertMessage;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::AssertKind;
         match self {
             AssertKind::BoundsCheck { len, index } => stable_mir::mir::AssertMessage::BoundsCheck {
@@ -468,7 +468,7 @@ impl<'tcx> Stable<'tcx> for mir::AssertMessage<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::BinOp {
     type T = stable_mir::mir::BinOp;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::BinOp;
         match self {
             BinOp::Add => stable_mir::mir::BinOp::Add,
@@ -499,7 +499,7 @@ impl<'tcx> Stable<'tcx> for mir::BinOp {
 
 impl<'tcx> Stable<'tcx> for mir::UnOp {
     type T = stable_mir::mir::UnOp;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::UnOp;
         match self {
             UnOp::Not => stable_mir::mir::UnOp::Not,
@@ -510,7 +510,7 @@ impl<'tcx> Stable<'tcx> for mir::UnOp {
 
 impl<'tcx> Stable<'tcx> for mir::AggregateKind<'tcx> {
     type T = stable_mir::mir::AggregateKind;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             mir::AggregateKind::Array(ty) => {
                 stable_mir::mir::AggregateKind::Array(ty.stable(tables))
@@ -544,7 +544,7 @@ impl<'tcx> Stable<'tcx> for mir::AggregateKind<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::InlineAsmOperand<'tcx> {
     type T = stable_mir::mir::InlineAsmOperand;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::mir::InlineAsmOperand;
 
         let (in_value, out_place) = match self {
@@ -564,7 +564,7 @@ impl<'tcx> Stable<'tcx> for mir::InlineAsmOperand<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::Terminator<'tcx> {
     type T = stable_mir::mir::Terminator;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::mir::Terminator;
         Terminator { kind: self.kind.stable(tables), span: self.source_info.span.stable(tables) }
     }
@@ -572,7 +572,7 @@ impl<'tcx> Stable<'tcx> for mir::Terminator<'tcx> {
 
 impl<'tcx> Stable<'tcx> for mir::TerminatorKind<'tcx> {
     type T = stable_mir::mir::TerminatorKind;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::mir::TerminatorKind;
         match self {
             mir::TerminatorKind::Goto { target } => {
@@ -649,7 +649,7 @@ impl<'tcx> Stable<'tcx> for mir::TerminatorKind<'tcx> {
 impl<'tcx> Stable<'tcx> for mir::interpret::ConstAllocation<'tcx> {
     type T = Allocation;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         self.inner().stable(tables)
     }
 }
@@ -657,7 +657,7 @@ impl<'tcx> Stable<'tcx> for mir::interpret::ConstAllocation<'tcx> {
 impl<'tcx> Stable<'tcx> for mir::interpret::Allocation {
     type T = stable_mir::ty::Allocation;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         alloc::allocation_filter(
             self,
             alloc_range(rustc_target::abi::Size::ZERO, self.size()),
@@ -668,7 +668,7 @@ impl<'tcx> Stable<'tcx> for mir::interpret::Allocation {
 
 impl<'tcx> Stable<'tcx> for mir::interpret::AllocId {
     type T = stable_mir::mir::alloc::AllocId;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         tables.create_alloc_id(*self)
     }
 }
@@ -676,7 +676,7 @@ impl<'tcx> Stable<'tcx> for mir::interpret::AllocId {
 impl<'tcx> Stable<'tcx> for mir::interpret::GlobalAlloc<'tcx> {
     type T = GlobalAlloc;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             mir::interpret::GlobalAlloc::Function(instance) => {
                 GlobalAlloc::Function(instance.stable(tables))
@@ -695,7 +695,7 @@ impl<'tcx> Stable<'tcx> for mir::interpret::GlobalAlloc<'tcx> {
 impl<'tcx> Stable<'tcx> for rustc_middle::mir::Const<'tcx> {
     type T = stable_mir::ty::Const;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match *self {
             mir::Const::Ty(c) => c.stable(tables),
             mir::Const::Unevaluated(unev_const, ty) => {
@@ -706,18 +706,20 @@ impl<'tcx> Stable<'tcx> for rustc_middle::mir::Const<'tcx> {
                         promoted: unev_const.promoted.map(|u| u.as_u32()),
                     });
                 let ty = ty.stable(tables);
-                let id = tables.intern_const(*self);
+                let id = tables.intern_const(tables.tcx.lift(*self).unwrap());
                 Const::new(kind, ty, id)
             }
             mir::Const::Val(mir::ConstValue::ZeroSized, ty) => {
                 let ty = ty.stable(tables);
-                let id = tables.intern_const(*self);
+                let id = tables.intern_const(tables.tcx.lift(*self).unwrap());
                 Const::new(ConstantKind::ZeroSized, ty, id)
             }
             mir::Const::Val(val, ty) => {
+                let ty = tables.tcx.lift(ty).unwrap();
+                let val = tables.tcx.lift(val).unwrap();
                 let kind = ConstantKind::Allocated(alloc::new_allocation(ty, val, tables));
                 let ty = ty.stable(tables);
-                let id = tables.intern_const(*self);
+                let id = tables.intern_const(tables.tcx.lift(*self).unwrap());
                 Const::new(kind, ty, id)
             }
         }
@@ -727,7 +729,7 @@ impl<'tcx> Stable<'tcx> for rustc_middle::mir::Const<'tcx> {
 impl<'tcx> Stable<'tcx> for mir::interpret::ErrorHandled {
     type T = Error;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         Error::new(format!("{self:?}"))
     }
 }
@@ -735,7 +737,7 @@ impl<'tcx> Stable<'tcx> for mir::interpret::ErrorHandled {
 impl<'tcx> Stable<'tcx> for MonoItem<'tcx> {
     type T = stable_mir::mir::mono::MonoItem;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::mir::mono::MonoItem as StableMonoItem;
         match self {
             MonoItem::Fn(instance) => StableMonoItem::Fn(instance.stable(tables)),
diff --git a/compiler/rustc_smir/src/rustc_smir/convert/mod.rs b/compiler/rustc_smir/src/rustc_smir/convert/mod.rs
index 2446671770ecb..41b0a84dd80f1 100644
--- a/compiler/rustc_smir/src/rustc_smir/convert/mod.rs
+++ b/compiler/rustc_smir/src/rustc_smir/convert/mod.rs
@@ -11,7 +11,7 @@ mod ty;
 
 impl<'tcx> Stable<'tcx> for rustc_hir::Unsafety {
     type T = stable_mir::mir::Safety;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             rustc_hir::Unsafety::Unsafe => stable_mir::mir::Safety::Unsafe,
             rustc_hir::Unsafety::Normal => stable_mir::mir::Safety::Normal,
@@ -21,14 +21,14 @@ impl<'tcx> Stable<'tcx> for rustc_hir::Unsafety {
 
 impl<'tcx> Stable<'tcx> for FieldIdx {
     type T = usize;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         self.as_usize()
     }
 }
 
 impl<'tcx> Stable<'tcx> for rustc_hir::CoroutineSource {
     type T = stable_mir::mir::CoroutineSource;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_hir::CoroutineSource;
         match self {
             CoroutineSource::Block => stable_mir::mir::CoroutineSource::Block,
@@ -40,7 +40,7 @@ impl<'tcx> Stable<'tcx> for rustc_hir::CoroutineSource {
 
 impl<'tcx> Stable<'tcx> for rustc_hir::CoroutineKind {
     type T = stable_mir::mir::CoroutineKind;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_hir::{CoroutineDesugaring, CoroutineKind};
         match *self {
             CoroutineKind::Desugared(CoroutineDesugaring::Async, source) => {
@@ -71,7 +71,7 @@ impl<'tcx> Stable<'tcx> for rustc_hir::CoroutineKind {
 impl<'tcx> Stable<'tcx> for rustc_span::Symbol {
     type T = stable_mir::Symbol;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         self.to_string()
     }
 }
@@ -79,7 +79,7 @@ impl<'tcx> Stable<'tcx> for rustc_span::Symbol {
 impl<'tcx> Stable<'tcx> for rustc_span::Span {
     type T = stable_mir::ty::Span;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         tables.create_span(*self)
     }
 }
diff --git a/compiler/rustc_smir/src/rustc_smir/convert/ty.rs b/compiler/rustc_smir/src/rustc_smir/convert/ty.rs
index c0ecbfb991413..cffbdc376f1fa 100644
--- a/compiler/rustc_smir/src/rustc_smir/convert/ty.rs
+++ b/compiler/rustc_smir/src/rustc_smir/convert/ty.rs
@@ -11,7 +11,7 @@ use crate::rustc_smir::{alloc, Stable, Tables};
 
 impl<'tcx> Stable<'tcx> for ty::AliasKind {
     type T = stable_mir::ty::AliasKind;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             ty::Projection => stable_mir::ty::AliasKind::Projection,
             ty::Inherent => stable_mir::ty::AliasKind::Inherent,
@@ -23,7 +23,7 @@ impl<'tcx> Stable<'tcx> for ty::AliasKind {
 
 impl<'tcx> Stable<'tcx> for ty::AliasTy<'tcx> {
     type T = stable_mir::ty::AliasTy;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::AliasTy { args, def_id, .. } = self;
         stable_mir::ty::AliasTy { def_id: tables.alias_def(*def_id), args: args.stable(tables) }
     }
@@ -32,7 +32,7 @@ impl<'tcx> Stable<'tcx> for ty::AliasTy<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::DynKind {
     type T = stable_mir::ty::DynKind;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             ty::Dyn => stable_mir::ty::DynKind::Dyn,
             ty::DynStar => stable_mir::ty::DynKind::DynStar,
@@ -43,7 +43,7 @@ impl<'tcx> Stable<'tcx> for ty::DynKind {
 impl<'tcx> Stable<'tcx> for ty::ExistentialPredicate<'tcx> {
     type T = stable_mir::ty::ExistentialPredicate;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::ExistentialPredicate::*;
         match self {
             ty::ExistentialPredicate::Trait(existential_trait_ref) => {
@@ -60,7 +60,7 @@ impl<'tcx> Stable<'tcx> for ty::ExistentialPredicate<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::ExistentialTraitRef<'tcx> {
     type T = stable_mir::ty::ExistentialTraitRef;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::ExistentialTraitRef { def_id, args } = self;
         stable_mir::ty::ExistentialTraitRef {
             def_id: tables.trait_def(*def_id),
@@ -72,7 +72,7 @@ impl<'tcx> Stable<'tcx> for ty::ExistentialTraitRef<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::TermKind<'tcx> {
     type T = stable_mir::ty::TermKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::TermKind;
         match self {
             ty::TermKind::Ty(ty) => TermKind::Type(ty.stable(tables)),
@@ -87,7 +87,7 @@ impl<'tcx> Stable<'tcx> for ty::TermKind<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::ExistentialProjection<'tcx> {
     type T = stable_mir::ty::ExistentialProjection;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::ExistentialProjection { def_id, args, term } = self;
         stable_mir::ty::ExistentialProjection {
             def_id: tables.trait_def(*def_id),
@@ -99,7 +99,7 @@ impl<'tcx> Stable<'tcx> for ty::ExistentialProjection<'tcx> {
 
 impl<'tcx> Stable<'tcx> for ty::adjustment::PointerCoercion {
     type T = stable_mir::mir::PointerCoercion;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::ty::adjustment::PointerCoercion;
         match self {
             PointerCoercion::ReifyFnPointer => stable_mir::mir::PointerCoercion::ReifyFnPointer,
@@ -118,7 +118,7 @@ impl<'tcx> Stable<'tcx> for ty::adjustment::PointerCoercion {
 
 impl<'tcx> Stable<'tcx> for ty::UserTypeAnnotationIndex {
     type T = usize;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         self.as_usize()
     }
 }
@@ -126,7 +126,7 @@ impl<'tcx> Stable<'tcx> for ty::UserTypeAnnotationIndex {
 impl<'tcx> Stable<'tcx> for ty::AdtKind {
     type T = AdtKind;
 
-    fn stable(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _tables: &mut Tables<'_>) -> Self::T {
         match self {
             ty::AdtKind::Struct => AdtKind::Struct,
             ty::AdtKind::Union => AdtKind::Union,
@@ -138,7 +138,7 @@ impl<'tcx> Stable<'tcx> for ty::AdtKind {
 impl<'tcx> Stable<'tcx> for ty::FieldDef {
     type T = stable_mir::ty::FieldDef;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         stable_mir::ty::FieldDef {
             def: tables.create_def_id(self.did),
             name: self.name.stable(tables),
@@ -148,7 +148,7 @@ impl<'tcx> Stable<'tcx> for ty::FieldDef {
 
 impl<'tcx> Stable<'tcx> for ty::GenericArgs<'tcx> {
     type T = stable_mir::ty::GenericArgs;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         GenericArgs(self.iter().map(|arg| arg.unpack().stable(tables)).collect())
     }
 }
@@ -156,7 +156,7 @@ impl<'tcx> Stable<'tcx> for ty::GenericArgs<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::GenericArgKind<'tcx> {
     type T = stable_mir::ty::GenericArgKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::GenericArgKind;
         match self {
             ty::GenericArgKind::Lifetime(region) => GenericArgKind::Lifetime(region.stable(tables)),
@@ -172,7 +172,7 @@ where
 {
     type T = stable_mir::ty::Binder<V>;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::Binder;
 
         Binder {
@@ -192,7 +192,7 @@ where
 {
     type T = stable_mir::ty::EarlyBinder<V>;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::EarlyBinder;
 
         EarlyBinder { value: self.as_ref().skip_binder().stable(tables) }
@@ -201,7 +201,7 @@ where
 
 impl<'tcx> Stable<'tcx> for ty::FnSig<'tcx> {
     type T = stable_mir::ty::FnSig;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_target::spec::abi;
         use stable_mir::ty::{Abi, FnSig};
 
@@ -245,7 +245,7 @@ impl<'tcx> Stable<'tcx> for ty::FnSig<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::BoundTyKind {
     type T = stable_mir::ty::BoundTyKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::BoundTyKind;
 
         match self {
@@ -260,7 +260,7 @@ impl<'tcx> Stable<'tcx> for ty::BoundTyKind {
 impl<'tcx> Stable<'tcx> for ty::BoundRegionKind {
     type T = stable_mir::ty::BoundRegionKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::BoundRegionKind;
 
         match self {
@@ -276,7 +276,7 @@ impl<'tcx> Stable<'tcx> for ty::BoundRegionKind {
 impl<'tcx> Stable<'tcx> for ty::BoundVariableKind {
     type T = stable_mir::ty::BoundVariableKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::BoundVariableKind;
 
         match self {
@@ -294,7 +294,7 @@ impl<'tcx> Stable<'tcx> for ty::BoundVariableKind {
 impl<'tcx> Stable<'tcx> for ty::IntTy {
     type T = IntTy;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             ty::IntTy::Isize => IntTy::Isize,
             ty::IntTy::I8 => IntTy::I8,
@@ -309,7 +309,7 @@ impl<'tcx> Stable<'tcx> for ty::IntTy {
 impl<'tcx> Stable<'tcx> for ty::UintTy {
     type T = UintTy;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             ty::UintTy::Usize => UintTy::Usize,
             ty::UintTy::U8 => UintTy::U8,
@@ -324,7 +324,7 @@ impl<'tcx> Stable<'tcx> for ty::UintTy {
 impl<'tcx> Stable<'tcx> for ty::FloatTy {
     type T = FloatTy;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             ty::FloatTy::F32 => FloatTy::F32,
             ty::FloatTy::F64 => FloatTy::F64,
@@ -334,14 +334,14 @@ impl<'tcx> Stable<'tcx> for ty::FloatTy {
 
 impl<'tcx> Stable<'tcx> for Ty<'tcx> {
     type T = stable_mir::ty::Ty;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.intern_ty(*self)
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
+        tables.intern_ty(tables.tcx.lift(*self).unwrap())
     }
 }
 
 impl<'tcx> Stable<'tcx> for ty::TyKind<'tcx> {
     type T = stable_mir::ty::TyKind;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             ty::Bool => TyKind::RigidTy(RigidTy::Bool),
             ty::Char => TyKind::RigidTy(RigidTy::Char),
@@ -414,17 +414,22 @@ impl<'tcx> Stable<'tcx> for ty::TyKind<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::Const<'tcx> {
     type T = stable_mir::ty::Const;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let kind = match self.kind() {
             ty::Value(val) => {
-                let const_val = tables.tcx.valtree_to_const_val((self.ty(), val));
+                let val = match val {
+                    ty::ValTree::Leaf(scalar) => ty::ValTree::Leaf(scalar),
+                    ty::ValTree::Branch(branch) => {
+                        ty::ValTree::Branch(tables.tcx.lift(branch).unwrap())
+                    }
+                };
+                let ty = tables.tcx.lift(self.ty()).unwrap();
+                let const_val = tables.tcx.valtree_to_const_val((ty, val));
                 if matches!(const_val, mir::ConstValue::ZeroSized) {
                     ConstantKind::ZeroSized
                 } else {
                     stable_mir::ty::ConstantKind::Allocated(alloc::new_allocation(
-                        self.ty(),
-                        const_val,
-                        tables,
+                        ty, const_val, tables,
                     ))
                 }
             }
@@ -443,14 +448,14 @@ impl<'tcx> Stable<'tcx> for ty::Const<'tcx> {
             ty::ExprCt(_) => unimplemented!(),
         };
         let ty = self.ty().stable(tables);
-        let id = tables.intern_const(mir::Const::Ty(*self));
+        let id = tables.intern_const(mir::Const::Ty(tables.tcx.lift(*self).unwrap()));
         Const::new(kind, ty, id)
     }
 }
 
 impl<'tcx> Stable<'tcx> for ty::ParamConst {
     type T = stable_mir::ty::ParamConst;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::ParamConst;
         ParamConst { index: self.index, name: self.name.to_string() }
     }
@@ -458,7 +463,7 @@ impl<'tcx> Stable<'tcx> for ty::ParamConst {
 
 impl<'tcx> Stable<'tcx> for ty::ParamTy {
     type T = stable_mir::ty::ParamTy;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::ParamTy;
         ParamTy { index: self.index, name: self.name.to_string() }
     }
@@ -466,7 +471,7 @@ impl<'tcx> Stable<'tcx> for ty::ParamTy {
 
 impl<'tcx> Stable<'tcx> for ty::BoundTy {
     type T = stable_mir::ty::BoundTy;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::BoundTy;
         BoundTy { var: self.var.as_usize(), kind: self.kind.stable(tables) }
     }
@@ -474,7 +479,7 @@ impl<'tcx> Stable<'tcx> for ty::BoundTy {
 
 impl<'tcx> Stable<'tcx> for ty::trait_def::TraitSpecializationKind {
     type T = stable_mir::ty::TraitSpecializationKind;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::TraitSpecializationKind;
 
         match self {
@@ -489,7 +494,7 @@ impl<'tcx> Stable<'tcx> for ty::trait_def::TraitSpecializationKind {
 
 impl<'tcx> Stable<'tcx> for ty::TraitDef {
     type T = stable_mir::ty::TraitDecl;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::opaque;
         use stable_mir::ty::TraitDecl;
 
@@ -514,7 +519,7 @@ impl<'tcx> Stable<'tcx> for ty::TraitDef {
 
 impl<'tcx> Stable<'tcx> for ty::TraitRef<'tcx> {
     type T = stable_mir::ty::TraitRef;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::TraitRef;
 
         TraitRef::try_new(tables.trait_def(self.def_id), self.args.stable(tables)).unwrap()
@@ -524,7 +529,7 @@ impl<'tcx> Stable<'tcx> for ty::TraitRef<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::Generics {
     type T = stable_mir::ty::Generics;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::Generics;
 
         let params: Vec<_> = self.params.iter().map(|param| param.stable(tables)).collect();
@@ -549,7 +554,7 @@ impl<'tcx> Stable<'tcx> for ty::Generics {
 impl<'tcx> Stable<'tcx> for rustc_middle::ty::GenericParamDefKind {
     type T = stable_mir::ty::GenericParamDefKind;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::GenericParamDefKind;
         match self {
             ty::GenericParamDefKind::Lifetime => GenericParamDefKind::Lifetime,
@@ -566,7 +571,7 @@ impl<'tcx> Stable<'tcx> for rustc_middle::ty::GenericParamDefKind {
 impl<'tcx> Stable<'tcx> for rustc_middle::ty::GenericParamDef {
     type T = stable_mir::ty::GenericParamDef;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         GenericParamDef {
             name: self.name.to_string(),
             def_id: tables.generic_def(self.def_id),
@@ -580,7 +585,7 @@ impl<'tcx> Stable<'tcx> for rustc_middle::ty::GenericParamDef {
 impl<'tcx> Stable<'tcx> for ty::PredicateKind<'tcx> {
     type T = stable_mir::ty::PredicateKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::ty::PredicateKind;
         match self {
             PredicateKind::Clause(clause_kind) => {
@@ -614,7 +619,7 @@ impl<'tcx> Stable<'tcx> for ty::PredicateKind<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::ClauseKind<'tcx> {
     type T = stable_mir::ty::ClauseKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use rustc_middle::ty::ClauseKind;
         match *self {
             ClauseKind::Trait(trait_object) => {
@@ -650,7 +655,7 @@ impl<'tcx> Stable<'tcx> for ty::ClauseKind<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::ClosureKind {
     type T = stable_mir::ty::ClosureKind;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::ty::ClosureKind::*;
         match self {
             Fn => stable_mir::ty::ClosureKind::Fn,
@@ -663,7 +668,7 @@ impl<'tcx> Stable<'tcx> for ty::ClosureKind {
 impl<'tcx> Stable<'tcx> for ty::SubtypePredicate<'tcx> {
     type T = stable_mir::ty::SubtypePredicate;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::SubtypePredicate { a, b, a_is_expected: _ } = self;
         stable_mir::ty::SubtypePredicate { a: a.stable(tables), b: b.stable(tables) }
     }
@@ -672,7 +677,7 @@ impl<'tcx> Stable<'tcx> for ty::SubtypePredicate<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::CoercePredicate<'tcx> {
     type T = stable_mir::ty::CoercePredicate;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::CoercePredicate { a, b } = self;
         stable_mir::ty::CoercePredicate { a: a.stable(tables), b: b.stable(tables) }
     }
@@ -681,7 +686,7 @@ impl<'tcx> Stable<'tcx> for ty::CoercePredicate<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::AliasRelationDirection {
     type T = stable_mir::ty::AliasRelationDirection;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::ty::AliasRelationDirection::*;
         match self {
             Equate => stable_mir::ty::AliasRelationDirection::Equate,
@@ -693,7 +698,7 @@ impl<'tcx> Stable<'tcx> for ty::AliasRelationDirection {
 impl<'tcx> Stable<'tcx> for ty::TraitPredicate<'tcx> {
     type T = stable_mir::ty::TraitPredicate;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::TraitPredicate { trait_ref, polarity } = self;
         stable_mir::ty::TraitPredicate {
             trait_ref: trait_ref.stable(tables),
@@ -709,7 +714,7 @@ where
 {
     type T = stable_mir::ty::OutlivesPredicate<U, V>;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::OutlivesPredicate(a, b) = self;
         stable_mir::ty::OutlivesPredicate(a.stable(tables), b.stable(tables))
     }
@@ -718,7 +723,7 @@ where
 impl<'tcx> Stable<'tcx> for ty::ProjectionPredicate<'tcx> {
     type T = stable_mir::ty::ProjectionPredicate;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         let ty::ProjectionPredicate { projection_ty, term } = self;
         stable_mir::ty::ProjectionPredicate {
             projection_ty: projection_ty.stable(tables),
@@ -730,7 +735,7 @@ impl<'tcx> Stable<'tcx> for ty::ProjectionPredicate<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::ImplPolarity {
     type T = stable_mir::ty::ImplPolarity;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         use rustc_middle::ty::ImplPolarity::*;
         match self {
             Positive => stable_mir::ty::ImplPolarity::Positive,
@@ -743,7 +748,7 @@ impl<'tcx> Stable<'tcx> for ty::ImplPolarity {
 impl<'tcx> Stable<'tcx> for ty::Region<'tcx> {
     type T = stable_mir::ty::Region;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         Region { kind: self.kind().stable(tables) }
     }
 }
@@ -751,7 +756,7 @@ impl<'tcx> Stable<'tcx> for ty::Region<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::RegionKind<'tcx> {
     type T = stable_mir::ty::RegionKind;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         use stable_mir::ty::{BoundRegion, EarlyParamRegion, RegionKind};
         match self {
             ty::ReEarlyParam(early_reg) => RegionKind::ReEarlyParam(EarlyParamRegion {
@@ -782,8 +787,8 @@ impl<'tcx> Stable<'tcx> for ty::RegionKind<'tcx> {
 impl<'tcx> Stable<'tcx> for ty::Instance<'tcx> {
     type T = stable_mir::mir::mono::Instance;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        let def = tables.instance_def(*self);
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
+        let def = tables.instance_def(tables.tcx.lift(*self).unwrap());
         let kind = match self.def {
             ty::InstanceDef::Item(..) => stable_mir::mir::mono::InstanceKind::Item,
             ty::InstanceDef::Intrinsic(..) => stable_mir::mir::mono::InstanceKind::Intrinsic,
@@ -805,7 +810,7 @@ impl<'tcx> Stable<'tcx> for ty::Instance<'tcx> {
 
 impl<'tcx> Stable<'tcx> for ty::Variance {
     type T = stable_mir::mir::Variance;
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             ty::Variance::Bivariant => stable_mir::mir::Variance::Bivariant,
             ty::Variance::Contravariant => stable_mir::mir::Variance::Contravariant,
@@ -818,7 +823,7 @@ impl<'tcx> Stable<'tcx> for ty::Variance {
 impl<'tcx> Stable<'tcx> for ty::Movability {
     type T = stable_mir::ty::Movability;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, _: &mut Tables<'_>) -> Self::T {
         match self {
             ty::Movability::Static => stable_mir::ty::Movability::Static,
             ty::Movability::Movable => stable_mir::ty::Movability::Movable,
diff --git a/compiler/rustc_smir/src/rustc_smir/mod.rs b/compiler/rustc_smir/src/rustc_smir/mod.rs
index e1ee40c0b60ee..bd02e52794c0c 100644
--- a/compiler/rustc_smir/src/rustc_smir/mod.rs
+++ b/compiler/rustc_smir/src/rustc_smir/mod.rs
@@ -102,11 +102,11 @@ pub(crate) fn new_item_kind(kind: DefKind) -> ItemKind {
 }
 
 /// Trait used to convert between an internal MIR type to a Stable MIR type.
-pub trait Stable<'tcx> {
+pub trait Stable<'cx> {
     /// The stable representation of the type implementing Stable.
     type T;
     /// Converts an object to the equivalent Stable MIR representation.
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T;
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T;
 }
 
 impl<'tcx, T> Stable<'tcx> for &T
@@ -115,7 +115,7 @@ where
 {
     type T = T::T;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         (*self).stable(tables)
     }
 }
@@ -126,7 +126,7 @@ where
 {
     type T = Option<T::T>;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         self.as_ref().map(|value| value.stable(tables))
     }
 }
@@ -138,7 +138,7 @@ where
 {
     type T = Result<T::T, E::T>;
 
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         match self {
             Ok(val) => Ok(val.stable(tables)),
             Err(error) => Err(error.stable(tables)),
@@ -151,7 +151,7 @@ where
     T: Stable<'tcx>,
 {
     type T = Vec<T::T>;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         self.iter().map(|e| e.stable(tables)).collect()
     }
 }
@@ -162,7 +162,7 @@ where
     U: Stable<'tcx>,
 {
     type T = (T::T, U::T);
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         (self.0.stable(tables), self.1.stable(tables))
     }
 }
@@ -172,7 +172,7 @@ where
     T: Stable<'tcx>,
 {
     type T = RangeInclusive<T::T>;
-    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn stable(&self, tables: &mut Tables<'_>) -> Self::T {
         RangeInclusive::new(self.start().stable(tables), self.end().stable(tables))
     }
 }

From 9aace6723572438a94378451793ca37deb768e72 Mon Sep 17 00:00:00 2001
From: "Celina G. Val" <celinval@amazon.com>
Date: Wed, 17 Jan 2024 18:35:19 -0800
Subject: [PATCH 05/12] Ensure internal function is safe

The internal function was unsound, it could cause UB in rare cases where
the user inadvertly stored the returned object in a location that could
outlive the TyCtxt.

In order to make it safe, we now take a type context as an argument to
the internal fn, and we ensure that interned items are lifted using the
provided context.

Thus, this change ensures that the compiler can properly enforce
that the object does not outlive the type context it was lifted to.
---
 .../rustc_smir/src/rustc_internal/internal.rs | 333 ++++++++++--------
 compiler/rustc_smir/src/rustc_internal/mod.rs |  39 +-
 compiler/rustc_smir/src/rustc_smir/alloc.rs   |   3 +-
 compiler/rustc_smir/src/rustc_smir/context.rs | 117 +++---
 tests/ui-fulldeps/stable-mir/smir_internal.rs |   4 +-
 5 files changed, 296 insertions(+), 200 deletions(-)

diff --git a/compiler/rustc_smir/src/rustc_internal/internal.rs b/compiler/rustc_smir/src/rustc_internal/internal.rs
index 5689e8f3b3d94..01260659fd53f 100644
--- a/compiler/rustc_smir/src/rustc_internal/internal.rs
+++ b/compiler/rustc_smir/src/rustc_internal/internal.rs
@@ -5,7 +5,7 @@
 
 // Prefer importing stable_mir over internal rustc constructs to make this file more readable.
 use crate::rustc_smir::Tables;
-use rustc_middle::ty::{self as rustc_ty, Ty as InternalTy};
+use rustc_middle::ty::{self as rustc_ty, Ty as InternalTy, TyCtxt};
 use rustc_span::Symbol;
 use stable_mir::abi::Layout;
 use stable_mir::mir::alloc::AllocId;
@@ -21,118 +21,120 @@ use stable_mir::{CrateItem, CrateNum, DefId};
 
 use super::RustcInternal;
 
-impl<'tcx> RustcInternal<'tcx> for CrateItem {
+unsafe impl<'tcx> RustcInternal<'tcx> for CrateItem {
     type T = rustc_span::def_id::DefId;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        self.0.internal(tables)
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        self.0.internal(tables, tcx)
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for CrateNum {
+unsafe impl<'tcx> RustcInternal<'tcx> for CrateNum {
     type T = rustc_span::def_id::CrateNum;
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         rustc_span::def_id::CrateNum::from_usize(*self)
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for DefId {
+unsafe impl<'tcx> RustcInternal<'tcx> for DefId {
     type T = rustc_span::def_id::DefId;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.def_ids[*self]
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.lift(tables.def_ids[*self]).unwrap()
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for GenericArgs {
+unsafe impl<'tcx> RustcInternal<'tcx> for GenericArgs {
     type T = rustc_ty::GenericArgsRef<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.tcx.mk_args_from_iter(self.0.iter().map(|arg| arg.internal(tables)))
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.mk_args_from_iter(self.0.iter().map(|arg| arg.internal(tables, tcx)))
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for GenericArgKind {
+unsafe impl<'tcx> RustcInternal<'tcx> for GenericArgKind {
     type T = rustc_ty::GenericArg<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        match self {
-            GenericArgKind::Lifetime(reg) => reg.internal(tables).into(),
-            GenericArgKind::Type(ty) => ty.internal(tables).into(),
-            GenericArgKind::Const(cnst) => ty_const(cnst, tables).into(),
-        }
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        let arg: rustc_ty::GenericArg<'tcx> = match self {
+            GenericArgKind::Lifetime(reg) => reg.internal(tables, tcx).into(),
+            GenericArgKind::Type(ty) => ty.internal(tables, tcx).into(),
+            GenericArgKind::Const(cnst) => ty_const(cnst, tables, tcx).into(),
+        };
+        tcx.lift(arg).unwrap()
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Region {
+unsafe impl<'tcx> RustcInternal<'tcx> for Region {
     type T = rustc_ty::Region<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        // Cannot recover region. Use erased instead.
-        tables.tcx.lifetimes.re_erased
+    fn internal(&self, _tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        // Cannot recover region. Use erased for now.
+        tcx.lifetimes.re_erased
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Ty {
+unsafe impl<'tcx> RustcInternal<'tcx> for Ty {
     type T = InternalTy<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.types[*self]
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.lift(tables.types[*self]).unwrap()
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for RigidTy {
+unsafe impl<'tcx> RustcInternal<'tcx> for RigidTy {
     type T = rustc_ty::TyKind<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             RigidTy::Bool => rustc_ty::TyKind::Bool,
             RigidTy::Char => rustc_ty::TyKind::Char,
-            RigidTy::Int(int_ty) => rustc_ty::TyKind::Int(int_ty.internal(tables)),
-            RigidTy::Uint(uint_ty) => rustc_ty::TyKind::Uint(uint_ty.internal(tables)),
-            RigidTy::Float(float_ty) => rustc_ty::TyKind::Float(float_ty.internal(tables)),
+            RigidTy::Int(int_ty) => rustc_ty::TyKind::Int(int_ty.internal(tables, tcx)),
+            RigidTy::Uint(uint_ty) => rustc_ty::TyKind::Uint(uint_ty.internal(tables, tcx)),
+            RigidTy::Float(float_ty) => rustc_ty::TyKind::Float(float_ty.internal(tables, tcx)),
             RigidTy::Never => rustc_ty::TyKind::Never,
             RigidTy::Array(ty, cnst) => {
-                rustc_ty::TyKind::Array(ty.internal(tables), ty_const(cnst, tables))
+                rustc_ty::TyKind::Array(ty.internal(tables, tcx), ty_const(cnst, tables, tcx))
             }
             RigidTy::Adt(def, args) => {
-                rustc_ty::TyKind::Adt(def.internal(tables), args.internal(tables))
+                rustc_ty::TyKind::Adt(def.internal(tables, tcx), args.internal(tables, tcx))
             }
             RigidTy::Str => rustc_ty::TyKind::Str,
-            RigidTy::Slice(ty) => rustc_ty::TyKind::Slice(ty.internal(tables)),
+            RigidTy::Slice(ty) => rustc_ty::TyKind::Slice(ty.internal(tables, tcx)),
             RigidTy::RawPtr(ty, mutability) => rustc_ty::TyKind::RawPtr(rustc_ty::TypeAndMut {
-                ty: ty.internal(tables),
-                mutbl: mutability.internal(tables),
+                ty: ty.internal(tables, tcx),
+                mutbl: mutability.internal(tables, tcx),
             }),
             RigidTy::Ref(region, ty, mutability) => rustc_ty::TyKind::Ref(
-                region.internal(tables),
-                ty.internal(tables),
-                mutability.internal(tables),
+                region.internal(tables, tcx),
+                ty.internal(tables, tcx),
+                mutability.internal(tables, tcx),
             ),
-            RigidTy::Foreign(def) => rustc_ty::TyKind::Foreign(def.0.internal(tables)),
+            RigidTy::Foreign(def) => rustc_ty::TyKind::Foreign(def.0.internal(tables, tcx)),
             RigidTy::FnDef(def, args) => {
-                rustc_ty::TyKind::FnDef(def.0.internal(tables), args.internal(tables))
+                rustc_ty::TyKind::FnDef(def.0.internal(tables, tcx), args.internal(tables, tcx))
             }
-            RigidTy::FnPtr(sig) => rustc_ty::TyKind::FnPtr(sig.internal(tables)),
+            RigidTy::FnPtr(sig) => rustc_ty::TyKind::FnPtr(sig.internal(tables, tcx)),
             RigidTy::Closure(def, args) => {
-                rustc_ty::TyKind::Closure(def.0.internal(tables), args.internal(tables))
+                rustc_ty::TyKind::Closure(def.0.internal(tables, tcx), args.internal(tables, tcx))
             }
             RigidTy::Coroutine(def, args, _mov) => {
-                rustc_ty::TyKind::Coroutine(def.0.internal(tables), args.internal(tables))
-            }
-            RigidTy::CoroutineWitness(def, args) => {
-                rustc_ty::TyKind::CoroutineWitness(def.0.internal(tables), args.internal(tables))
+                rustc_ty::TyKind::Coroutine(def.0.internal(tables, tcx), args.internal(tables, tcx))
             }
+            RigidTy::CoroutineWitness(def, args) => rustc_ty::TyKind::CoroutineWitness(
+                def.0.internal(tables, tcx),
+                args.internal(tables, tcx),
+            ),
             RigidTy::Dynamic(predicate, region, dyn_kind) => rustc_ty::TyKind::Dynamic(
-                tables.tcx.mk_poly_existential_predicates(&predicate.internal(tables)),
-                region.internal(tables),
-                dyn_kind.internal(tables),
+                tcx.mk_poly_existential_predicates(&predicate.internal(tables, tcx)),
+                region.internal(tables, tcx),
+                dyn_kind.internal(tables, tcx),
             ),
             RigidTy::Tuple(tys) => {
-                rustc_ty::TyKind::Tuple(tables.tcx.mk_type_list(&tys.internal(tables)))
+                rustc_ty::TyKind::Tuple(tcx.mk_type_list(&tys.internal(tables, tcx)))
             }
         }
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for IntTy {
+unsafe impl<'tcx> RustcInternal<'tcx> for IntTy {
     type T = rustc_ty::IntTy;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             IntTy::Isize => rustc_ty::IntTy::Isize,
             IntTy::I8 => rustc_ty::IntTy::I8,
@@ -144,10 +146,10 @@ impl<'tcx> RustcInternal<'tcx> for IntTy {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for UintTy {
+unsafe impl<'tcx> RustcInternal<'tcx> for UintTy {
     type T = rustc_ty::UintTy;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             UintTy::Usize => rustc_ty::UintTy::Usize,
             UintTy::U8 => rustc_ty::UintTy::U8,
@@ -159,10 +161,10 @@ impl<'tcx> RustcInternal<'tcx> for UintTy {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for FloatTy {
+unsafe impl<'tcx> RustcInternal<'tcx> for FloatTy {
     type T = rustc_ty::FloatTy;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             FloatTy::F32 => rustc_ty::FloatTy::F32,
             FloatTy::F64 => rustc_ty::FloatTy::F64,
@@ -170,10 +172,10 @@ impl<'tcx> RustcInternal<'tcx> for FloatTy {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Mutability {
+unsafe impl<'tcx> RustcInternal<'tcx> for Mutability {
     type T = rustc_ty::Mutability;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             Mutability::Not => rustc_ty::Mutability::Not,
             Mutability::Mut => rustc_ty::Mutability::Mut,
@@ -181,10 +183,10 @@ impl<'tcx> RustcInternal<'tcx> for Mutability {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Movability {
+unsafe impl<'tcx> RustcInternal<'tcx> for Movability {
     type T = rustc_ty::Movability;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             Movability::Static => rustc_ty::Movability::Static,
             Movability::Movable => rustc_ty::Movability::Movable,
@@ -192,37 +194,44 @@ impl<'tcx> RustcInternal<'tcx> for Movability {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for FnSig {
+unsafe impl<'tcx> RustcInternal<'tcx> for FnSig {
     type T = rustc_ty::FnSig<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        rustc_ty::FnSig {
-            inputs_and_output: tables.tcx.mk_type_list(&self.inputs_and_output.internal(tables)),
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.lift(rustc_ty::FnSig {
+            inputs_and_output: tables
+                .tcx
+                .mk_type_list(&self.inputs_and_output.internal(tables, tcx)),
             c_variadic: self.c_variadic,
-            unsafety: self.unsafety.internal(tables),
-            abi: self.abi.internal(tables),
-        }
+            unsafety: self.unsafety.internal(tables, tcx),
+            abi: self.abi.internal(tables, tcx),
+        })
+        .unwrap()
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for VariantIdx {
+unsafe impl<'tcx> RustcInternal<'tcx> for VariantIdx {
     type T = rustc_target::abi::VariantIdx;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         rustc_target::abi::VariantIdx::from(self.to_index())
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for VariantDef {
+unsafe impl<'tcx> RustcInternal<'tcx> for VariantDef {
     type T = &'tcx rustc_ty::VariantDef;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        self.adt_def.internal(tables).variant(self.idx.internal(tables))
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        self.adt_def.internal(tables, tcx).variant(self.idx.internal(tables, tcx))
     }
 }
 
-fn ty_const<'tcx>(constant: &Const, tables: &mut Tables<'tcx>) -> rustc_ty::Const<'tcx> {
-    match constant.internal(tables) {
+fn ty_const<'tcx>(
+    constant: &Const,
+    tables: &mut Tables<'tcx>,
+    tcx: TyCtxt<'tcx>,
+) -> rustc_ty::Const<'tcx> {
+    match constant.internal(tables, tcx) {
         rustc_middle::mir::Const::Ty(c) => c,
         cnst => {
             panic!("Trying to convert constant `{constant:?}` to type constant, but found {cnst:?}")
@@ -230,21 +239,33 @@ fn ty_const<'tcx>(constant: &Const, tables: &mut Tables<'tcx>) -> rustc_ty::Cons
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Const {
+unsafe impl<'tcx> RustcInternal<'tcx> for Const {
     type T = rustc_middle::mir::Const<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.constants[self.id]
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        let constant = tables.constants[self.id];
+        match constant {
+            rustc_middle::mir::Const::Ty(ty) => rustc_middle::mir::Const::Ty(tcx.lift(ty).unwrap()),
+            rustc_middle::mir::Const::Unevaluated(uneval, ty) => {
+                rustc_middle::mir::Const::Unevaluated(
+                    lift_unevaluated(tcx, uneval),
+                    tcx.lift(ty).unwrap(),
+                )
+            }
+            rustc_middle::mir::Const::Val(const_val, ty) => {
+                rustc_middle::mir::Const::Val(tcx.lift(const_val).unwrap(), tcx.lift(ty).unwrap())
+            }
+        }
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for MonoItem {
+unsafe impl<'tcx> RustcInternal<'tcx> for MonoItem {
     type T = rustc_middle::mir::mono::MonoItem<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         use rustc_middle::mir::mono as rustc_mono;
         match self {
-            MonoItem::Fn(instance) => rustc_mono::MonoItem::Fn(instance.internal(tables)),
-            MonoItem::Static(def) => rustc_mono::MonoItem::Static(def.internal(tables)),
+            MonoItem::Fn(instance) => rustc_mono::MonoItem::Fn(instance.internal(tables, tcx)),
+            MonoItem::Static(def) => rustc_mono::MonoItem::Static(def.internal(tables, tcx)),
             MonoItem::GlobalAsm(_) => {
                 unimplemented!()
             }
@@ -252,55 +273,56 @@ impl<'tcx> RustcInternal<'tcx> for MonoItem {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Instance {
+unsafe impl<'tcx> RustcInternal<'tcx> for Instance {
     type T = rustc_ty::Instance<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.instances[self.def]
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.lift(tables.instances[self.def]).unwrap()
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for StaticDef {
+unsafe impl<'tcx> RustcInternal<'tcx> for StaticDef {
     type T = rustc_span::def_id::DefId;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        self.0.internal(tables)
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        self.0.internal(tables, tcx)
     }
 }
 
 #[allow(rustc::usage_of_qualified_ty)]
-impl<'tcx, T> RustcInternal<'tcx> for Binder<T>
+unsafe impl<'tcx, T> RustcInternal<'tcx> for Binder<T>
 where
     T: RustcInternal<'tcx>,
     T::T: rustc_ty::TypeVisitable<rustc_ty::TyCtxt<'tcx>>,
 {
     type T = rustc_ty::Binder<'tcx, T::T>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         rustc_ty::Binder::bind_with_vars(
-            self.value.internal(tables),
-            tables.tcx.mk_bound_variable_kinds_from_iter(
-                self.bound_vars.iter().map(|bound| bound.internal(tables)),
+            self.value.internal(tables, tcx),
+            tcx.mk_bound_variable_kinds_from_iter(
+                self.bound_vars.iter().map(|bound| bound.internal(tables, tcx)),
             ),
         )
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for BoundVariableKind {
+unsafe impl<'tcx> RustcInternal<'tcx> for BoundVariableKind {
     type T = rustc_ty::BoundVariableKind;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             BoundVariableKind::Ty(kind) => rustc_ty::BoundVariableKind::Ty(match kind {
                 BoundTyKind::Anon => rustc_ty::BoundTyKind::Anon,
-                BoundTyKind::Param(def, symbol) => {
-                    rustc_ty::BoundTyKind::Param(def.0.internal(tables), Symbol::intern(symbol))
-                }
+                BoundTyKind::Param(def, symbol) => rustc_ty::BoundTyKind::Param(
+                    def.0.internal(tables, tcx),
+                    Symbol::intern(symbol),
+                ),
             }),
             BoundVariableKind::Region(kind) => rustc_ty::BoundVariableKind::Region(match kind {
                 BoundRegionKind::BrAnon => rustc_ty::BoundRegionKind::BrAnon,
                 BoundRegionKind::BrNamed(def, symbol) => rustc_ty::BoundRegionKind::BrNamed(
-                    def.0.internal(tables),
+                    def.0.internal(tables, tcx),
                     Symbol::intern(symbol),
                 ),
                 BoundRegionKind::BrEnv => rustc_ty::BoundRegionKind::BrEnv,
@@ -310,10 +332,10 @@ impl<'tcx> RustcInternal<'tcx> for BoundVariableKind {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for DynKind {
+unsafe impl<'tcx> RustcInternal<'tcx> for DynKind {
     type T = rustc_ty::DynKind;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             DynKind::Dyn => rustc_ty::DynKind::Dyn,
             DynKind::DynStar => rustc_ty::DynKind::DynStar,
@@ -321,81 +343,81 @@ impl<'tcx> RustcInternal<'tcx> for DynKind {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for ExistentialPredicate {
+unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialPredicate {
     type T = rustc_ty::ExistentialPredicate<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             ExistentialPredicate::Trait(trait_ref) => {
-                rustc_ty::ExistentialPredicate::Trait(trait_ref.internal(tables))
+                rustc_ty::ExistentialPredicate::Trait(trait_ref.internal(tables, tcx))
             }
             ExistentialPredicate::Projection(proj) => {
-                rustc_ty::ExistentialPredicate::Projection(proj.internal(tables))
+                rustc_ty::ExistentialPredicate::Projection(proj.internal(tables, tcx))
             }
             ExistentialPredicate::AutoTrait(trait_def) => {
-                rustc_ty::ExistentialPredicate::AutoTrait(trait_def.0.internal(tables))
+                rustc_ty::ExistentialPredicate::AutoTrait(trait_def.0.internal(tables, tcx))
             }
         }
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for ExistentialProjection {
+unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialProjection {
     type T = rustc_ty::ExistentialProjection<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         rustc_ty::ExistentialProjection {
-            def_id: self.def_id.0.internal(tables),
-            args: self.generic_args.internal(tables),
-            term: self.term.internal(tables),
+            def_id: self.def_id.0.internal(tables, tcx),
+            args: self.generic_args.internal(tables, tcx),
+            term: self.term.internal(tables, tcx),
         }
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for TermKind {
+unsafe impl<'tcx> RustcInternal<'tcx> for TermKind {
     type T = rustc_ty::Term<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
-            TermKind::Type(ty) => ty.internal(tables).into(),
-            TermKind::Const(const_) => ty_const(const_, tables).into(),
+            TermKind::Type(ty) => ty.internal(tables, tcx).into(),
+            TermKind::Const(const_) => ty_const(const_, tables, tcx).into(),
         }
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for ExistentialTraitRef {
+unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialTraitRef {
     type T = rustc_ty::ExistentialTraitRef<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         rustc_ty::ExistentialTraitRef {
-            def_id: self.def_id.0.internal(tables),
-            args: self.generic_args.internal(tables),
+            def_id: self.def_id.0.internal(tables, tcx),
+            args: self.generic_args.internal(tables, tcx),
         }
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for TraitRef {
+unsafe impl<'tcx> RustcInternal<'tcx> for TraitRef {
     type T = rustc_ty::TraitRef<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
         rustc_ty::TraitRef::new(
-            tables.tcx,
-            self.def_id.0.internal(tables),
-            self.args().internal(tables),
+            tcx,
+            self.def_id.0.internal(tables, tcx),
+            self.args().internal(tables, tcx),
         )
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for AllocId {
+unsafe impl<'tcx> RustcInternal<'tcx> for AllocId {
     type T = rustc_middle::mir::interpret::AllocId;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.alloc_ids[*self]
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.lift(tables.alloc_ids[*self]).unwrap()
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for ClosureKind {
+unsafe impl<'tcx> RustcInternal<'tcx> for ClosureKind {
     type T = rustc_ty::ClosureKind;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             ClosureKind::Fn => rustc_ty::ClosureKind::Fn,
             ClosureKind::FnMut => rustc_ty::ClosureKind::FnMut,
@@ -404,17 +426,17 @@ impl<'tcx> RustcInternal<'tcx> for ClosureKind {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for AdtDef {
+unsafe impl<'tcx> RustcInternal<'tcx> for AdtDef {
     type T = rustc_ty::AdtDef<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.tcx.adt_def(self.0.internal(&mut *tables))
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.adt_def(self.0.internal(tables, tcx))
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Abi {
+unsafe impl<'tcx> RustcInternal<'tcx> for Abi {
     type T = rustc_target::spec::abi::Abi;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match *self {
             Abi::Rust => rustc_target::spec::abi::Abi::Rust,
             Abi::C { unwind } => rustc_target::spec::abi::Abi::C { unwind },
@@ -447,10 +469,10 @@ impl<'tcx> RustcInternal<'tcx> for Abi {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Safety {
+unsafe impl<'tcx> RustcInternal<'tcx> for Safety {
     type T = rustc_hir::Unsafety;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         match self {
             Safety::Unsafe => rustc_hir::Unsafety::Unsafe,
             Safety::Normal => rustc_hir::Unsafety::Normal,
@@ -458,51 +480,62 @@ impl<'tcx> RustcInternal<'tcx> for Safety {
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Span {
+unsafe impl<'tcx> RustcInternal<'tcx> for Span {
     type T = rustc_span::Span;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+    fn internal(&self, tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
         tables[*self]
     }
 }
 
-impl<'tcx> RustcInternal<'tcx> for Layout {
+unsafe impl<'tcx> RustcInternal<'tcx> for Layout {
     type T = rustc_target::abi::Layout<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        tables.layouts[*self]
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        tcx.lift(tables.layouts[*self]).unwrap()
     }
 }
 
-impl<'tcx, T> RustcInternal<'tcx> for &T
+unsafe impl<'tcx, T> RustcInternal<'tcx> for &T
 where
     T: RustcInternal<'tcx>,
 {
     type T = T::T;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        (*self).internal(tables)
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        (*self).internal(tables, tcx)
     }
 }
 
-impl<'tcx, T> RustcInternal<'tcx> for Option<T>
+unsafe impl<'tcx, T> RustcInternal<'tcx> for Option<T>
 where
     T: RustcInternal<'tcx>,
 {
     type T = Option<T::T>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        self.as_ref().map(|inner| inner.internal(tables))
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        self.as_ref().map(|inner| inner.internal(tables, tcx))
     }
 }
 
-impl<'tcx, T> RustcInternal<'tcx> for Vec<T>
+unsafe impl<'tcx, T> RustcInternal<'tcx> for Vec<T>
 where
     T: RustcInternal<'tcx>,
 {
     type T = Vec<T::T>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
-        self.iter().map(|e| e.internal(tables)).collect()
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+        self.iter().map(|e| e.internal(tables, tcx)).collect()
+    }
+}
+
+fn lift_unevaluated<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    uneval: rustc_middle::mir::UnevaluatedConst<'tcx>,
+) -> rustc_middle::mir::UnevaluatedConst<'tcx> {
+    rustc_middle::mir::UnevaluatedConst {
+        def: uneval.def,
+        args: tcx.lift(uneval.args).unwrap(),
+        promoted: uneval.promoted,
     }
 }
diff --git a/compiler/rustc_smir/src/rustc_internal/mod.rs b/compiler/rustc_smir/src/rustc_internal/mod.rs
index cd4ad724b00af..b17ad153ed5ba 100644
--- a/compiler/rustc_smir/src/rustc_internal/mod.rs
+++ b/compiler/rustc_smir/src/rustc_internal/mod.rs
@@ -24,12 +24,38 @@ use std::ops::Index;
 mod internal;
 pub mod pretty;
 
+/// Convert an internal Rust compiler item into its stable counterpart, if one exists.
+///
+/// # Warning
+///
+/// This function is unstable, and its behavior may change at any point.
+/// E.g.: Items that were previously supported, may no longer be supported, or its translation may
+/// change.
+///
+/// # Panics
+///
+/// This function will panic if StableMIR has not been properly initialized.
 pub fn stable<'tcx, S: Stable<'tcx>>(item: S) -> S::T {
     with_tables(|tables| item.stable(tables))
 }
 
-pub fn internal<'tcx, S: RustcInternal<'tcx>>(item: S) -> S::T {
-    with_tables(|tables| item.internal(tables))
+/// Convert a stable item into its internal Rust compiler counterpart, if one exists.
+///
+/// # Warning
+///
+/// This function is unstable, and it's behavior may change at any point.
+/// Not every stable item can be converted to an internal one.
+/// Furthermore, items that were previously supported, may no longer be supported in newer versions.
+///
+/// # Panics
+///
+/// This function will panic if StableMIR has not been properly initialized.
+pub fn internal<'tcx, S>(tcx: TyCtxt<'tcx>, item: S) -> S::T
+where
+    S: RustcInternal<'tcx>,
+{
+    // The tcx argument ensures that the item won't outlive the type context.
+    with_tables(|tables| item.internal(tables, tcx))
 }
 
 impl<'tcx> Index<stable_mir::DefId> for Tables<'tcx> {
@@ -393,7 +419,12 @@ impl<K: PartialEq + Hash + Eq, V: Copy + Debug + PartialEq + IndexedVal> Index<V
 /// Trait used to translate a stable construct to its rustc counterpart.
 ///
 /// This is basically a mirror of [crate::rustc_smir::Stable].
-pub trait RustcInternal<'tcx> {
+///
+/// # Safety
+///
+/// This trait is unsafe, and every implementation should ensure that their translation
+/// is lifted if necessary with the given type context (`tcx`).
+pub unsafe trait RustcInternal<'tcx> {
     type T;
-    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T;
+    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T;
 }
diff --git a/compiler/rustc_smir/src/rustc_smir/alloc.rs b/compiler/rustc_smir/src/rustc_smir/alloc.rs
index 48cb164c308a7..5d02e3d6e9213 100644
--- a/compiler/rustc_smir/src/rustc_smir/alloc.rs
+++ b/compiler/rustc_smir/src/rustc_smir/alloc.rs
@@ -27,7 +27,8 @@ pub fn new_allocation<'tcx>(
     const_value: ConstValue<'tcx>,
     tables: &mut Tables<'tcx>,
 ) -> Allocation {
-    try_new_allocation(ty, const_value, tables).unwrap()
+    try_new_allocation(ty, const_value, tables)
+        .expect(&format!("Failed to convert: {const_value:?} to {ty:?}"))
 }
 
 #[allow(rustc::usage_of_qualified_ty)]
diff --git a/compiler/rustc_smir/src/rustc_smir/context.rs b/compiler/rustc_smir/src/rustc_smir/context.rs
index fffc454804d29..10085f659b370 100644
--- a/compiler/rustc_smir/src/rustc_smir/context.rs
+++ b/compiler/rustc_smir/src/rustc_smir/context.rs
@@ -29,7 +29,7 @@ use stable_mir::{Crate, CrateItem, CrateNum, DefId, Error, Filename, ItemKind, S
 use std::cell::RefCell;
 use std::iter;
 
-use crate::rustc_internal::{internal, RustcInternal};
+use crate::rustc_internal::RustcInternal;
 use crate::rustc_smir::builder::BodyBuilder;
 use crate::rustc_smir::{alloc, new_item_kind, smir_crate, Stable, Tables};
 
@@ -74,9 +74,8 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn trait_decls(&self, crate_num: CrateNum) -> stable_mir::TraitDecls {
         let mut tables = self.0.borrow_mut();
-        tables
-            .tcx
-            .traits(crate_num.internal(&mut *tables))
+        let tcx = tables.tcx;
+        tcx.traits(crate_num.internal(&mut *tables, tcx))
             .iter()
             .map(|trait_def_id| tables.trait_def(*trait_def_id))
             .collect()
@@ -101,9 +100,8 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn trait_impls(&self, crate_num: CrateNum) -> stable_mir::ImplTraitDecls {
         let mut tables = self.0.borrow_mut();
-        tables
-            .tcx
-            .trait_impls_in_crate(crate_num.internal(&mut *tables))
+        let tcx = tables.tcx;
+        tcx.trait_impls_in_crate(crate_num.internal(&mut *tables, tcx))
             .iter()
             .map(|impl_def_id| tables.impl_def(*impl_def_id))
             .collect()
@@ -229,57 +227,68 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn adt_kind(&self, def: AdtDef) -> AdtKind {
         let mut tables = self.0.borrow_mut();
-        def.internal(&mut *tables).adt_kind().stable(&mut *tables)
+        let tcx = tables.tcx;
+        def.internal(&mut *tables, tcx).adt_kind().stable(&mut *tables)
     }
 
     fn adt_is_box(&self, def: AdtDef) -> bool {
         let mut tables = self.0.borrow_mut();
-        def.internal(&mut *tables).is_box()
+        let tcx = tables.tcx;
+        def.internal(&mut *tables, tcx).is_box()
     }
 
     fn adt_is_simd(&self, def: AdtDef) -> bool {
         let mut tables = self.0.borrow_mut();
-        def.internal(&mut *tables).repr().simd()
+        let tcx = tables.tcx;
+        def.internal(&mut *tables, tcx).repr().simd()
     }
 
     fn adt_is_cstr(&self, def: AdtDef) -> bool {
         let mut tables = self.0.borrow_mut();
-        let def_id = def.0.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
         tables.tcx.lang_items().c_str() == Some(def_id)
     }
 
     fn fn_sig(&self, def: FnDef, args: &GenericArgs) -> PolyFnSig {
         let mut tables = self.0.borrow_mut();
-        let def_id = def.0.internal(&mut *tables);
-        let sig = tables.tcx.fn_sig(def_id).instantiate(tables.tcx, args.internal(&mut *tables));
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
+        let sig =
+            tables.tcx.fn_sig(def_id).instantiate(tables.tcx, args.internal(&mut *tables, tcx));
         sig.stable(&mut *tables)
     }
 
     fn closure_sig(&self, args: &GenericArgs) -> PolyFnSig {
         let mut tables = self.0.borrow_mut();
-        let args_ref = args.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let args_ref = args.internal(&mut *tables, tcx);
         let sig = args_ref.as_closure().sig();
         sig.stable(&mut *tables)
     }
 
     fn adt_variants_len(&self, def: AdtDef) -> usize {
         let mut tables = self.0.borrow_mut();
-        def.internal(&mut *tables).variants().len()
+        let tcx = tables.tcx;
+        def.internal(&mut *tables, tcx).variants().len()
     }
 
     fn variant_name(&self, def: VariantDef) -> Symbol {
         let mut tables = self.0.borrow_mut();
-        def.internal(&mut *tables).name.to_string()
+        let tcx = tables.tcx;
+        def.internal(&mut *tables, tcx).name.to_string()
     }
 
     fn variant_fields(&self, def: VariantDef) -> Vec<FieldDef> {
         let mut tables = self.0.borrow_mut();
-        def.internal(&mut *tables).fields.iter().map(|f| f.stable(&mut *tables)).collect()
+        let tcx = tables.tcx;
+        def.internal(&mut *tables, tcx).fields.iter().map(|f| f.stable(&mut *tables)).collect()
     }
 
     fn eval_target_usize(&self, cnst: &Const) -> Result<u64, Error> {
         let mut tables = self.0.borrow_mut();
-        let mir_const = cnst.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let mir_const = cnst.internal(&mut *tables, tcx);
         mir_const
             .try_eval_target_usize(tables.tcx, ParamEnv::empty())
             .ok_or_else(|| Error::new(format!("Const `{cnst:?}` cannot be encoded as u64")))
@@ -299,30 +308,36 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn new_rigid_ty(&self, kind: RigidTy) -> stable_mir::ty::Ty {
         let mut tables = self.0.borrow_mut();
-        let internal_kind = kind.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let internal_kind = kind.internal(&mut *tables, tcx);
         tables.tcx.mk_ty_from_kind(internal_kind).stable(&mut *tables)
     }
 
     fn new_box_ty(&self, ty: stable_mir::ty::Ty) -> stable_mir::ty::Ty {
         let mut tables = self.0.borrow_mut();
-        let inner = ty.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let inner = ty.internal(&mut *tables, tcx);
         ty::Ty::new_box(tables.tcx, inner).stable(&mut *tables)
     }
 
     fn def_ty(&self, item: stable_mir::DefId) -> stable_mir::ty::Ty {
         let mut tables = self.0.borrow_mut();
-        tables.tcx.type_of(item.internal(&mut *tables)).instantiate_identity().stable(&mut *tables)
+        let tcx = tables.tcx;
+        tcx.type_of(item.internal(&mut *tables, tcx)).instantiate_identity().stable(&mut *tables)
     }
 
     fn def_ty_with_args(&self, item: stable_mir::DefId, args: &GenericArgs) -> stable_mir::ty::Ty {
         let mut tables = self.0.borrow_mut();
-        let args = args.internal(&mut *tables);
-        let def_ty = tables.tcx.type_of(item.internal(&mut *tables));
+        let tcx = tables.tcx;
+        let args = args.internal(&mut *tables, tcx);
+        let def_ty = tables.tcx.type_of(item.internal(&mut *tables, tcx));
         def_ty.instantiate(tables.tcx, args).stable(&mut *tables)
     }
 
     fn const_literal(&self, cnst: &stable_mir::ty::Const) -> String {
-        internal(cnst).to_string()
+        let mut tables = self.0.borrow_mut();
+        let tcx = tables.tcx;
+        cnst.internal(&mut *tables, tcx).to_string()
     }
 
     fn span_of_an_item(&self, def_id: stable_mir::DefId) -> Span {
@@ -337,7 +352,8 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn rigid_ty_discriminant_ty(&self, ty: &RigidTy) -> stable_mir::ty::Ty {
         let mut tables = self.0.borrow_mut();
-        let internal_kind = ty.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let internal_kind = ty.internal(&mut *tables, tcx);
         let internal_ty = tables.tcx.mk_ty_from_kind(internal_kind);
         internal_ty.discriminant_ty(tables.tcx).stable(&mut *tables)
     }
@@ -407,8 +423,9 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         args: &stable_mir::ty::GenericArgs,
     ) -> Option<stable_mir::mir::mono::Instance> {
         let mut tables = self.0.borrow_mut();
-        let def_id = def.0.internal(&mut *tables);
-        let args_ref = args.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
+        let args_ref = args.internal(&mut *tables, tcx);
         match Instance::resolve(tables.tcx, ParamEnv::reveal_all(), def_id, args_ref) {
             Ok(Some(instance)) => Some(instance.stable(&mut *tables)),
             Ok(None) | Err(_) => None,
@@ -417,7 +434,8 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn resolve_drop_in_place(&self, ty: stable_mir::ty::Ty) -> stable_mir::mir::mono::Instance {
         let mut tables = self.0.borrow_mut();
-        let internal_ty = ty.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let internal_ty = ty.internal(&mut *tables, tcx);
         let instance = Instance::resolve_drop_in_place(tables.tcx, internal_ty);
         instance.stable(&mut *tables)
     }
@@ -428,8 +446,9 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         args: &GenericArgs,
     ) -> Option<stable_mir::mir::mono::Instance> {
         let mut tables = self.0.borrow_mut();
-        let def_id = def.0.internal(&mut *tables);
-        let args_ref = args.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
+        let args_ref = args.internal(&mut *tables, tcx);
         Instance::resolve_for_fn_ptr(tables.tcx, ParamEnv::reveal_all(), def_id, args_ref)
             .stable(&mut *tables)
     }
@@ -441,36 +460,44 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         kind: ClosureKind,
     ) -> Option<stable_mir::mir::mono::Instance> {
         let mut tables = self.0.borrow_mut();
-        let def_id = def.0.internal(&mut *tables);
-        let args_ref = args.internal(&mut *tables);
-        let closure_kind = kind.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
+        let args_ref = args.internal(&mut *tables, tcx);
+        let closure_kind = kind.internal(&mut *tables, tcx);
         Instance::resolve_closure(tables.tcx, def_id, args_ref, closure_kind).stable(&mut *tables)
     }
 
     fn eval_instance(&self, def: InstanceDef, const_ty: Ty) -> Result<Allocation, Error> {
         let mut tables = self.0.borrow_mut();
         let instance = tables.instances[def];
-        let result = tables.tcx.const_eval_instance(
+        let tcx = tables.tcx;
+        let result = tcx.const_eval_instance(
             ParamEnv::reveal_all(),
             instance,
-            Some(tables.tcx.def_span(instance.def_id())),
+            Some(tcx.def_span(instance.def_id())),
         );
         result
             .map(|const_val| {
-                alloc::try_new_allocation(const_ty.internal(&mut *tables), const_val, &mut *tables)
+                alloc::try_new_allocation(
+                    const_ty.internal(&mut *tables, tcx),
+                    const_val,
+                    &mut *tables,
+                )
             })
             .map_err(|e| e.stable(&mut *tables))?
     }
 
     fn eval_static_initializer(&self, def: StaticDef) -> Result<Allocation, Error> {
         let mut tables = self.0.borrow_mut();
-        let def_id = def.0.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
         tables.tcx.eval_static_initializer(def_id).stable(&mut *tables)
     }
 
     fn global_alloc(&self, alloc: stable_mir::mir::alloc::AllocId) -> GlobalAlloc {
         let mut tables = self.0.borrow_mut();
-        let alloc_id = alloc.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let alloc_id = alloc.internal(&mut *tables, tcx);
         tables.tcx.global_alloc(alloc_id).stable(&mut *tables)
     }
 
@@ -480,9 +507,11 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
     ) -> Option<stable_mir::mir::alloc::AllocId> {
         let mut tables = self.0.borrow_mut();
         let GlobalAlloc::VTable(ty, trait_ref) = global_alloc else { return None };
-        let alloc_id = tables
-            .tcx
-            .vtable_allocation((ty.internal(&mut *tables), trait_ref.internal(&mut *tables)));
+        let tcx = tables.tcx;
+        let alloc_id = tables.tcx.vtable_allocation((
+            ty.internal(&mut *tables, tcx),
+            trait_ref.internal(&mut *tables, tcx),
+        ));
         Some(alloc_id.stable(&mut *tables))
     }
 
@@ -510,14 +539,16 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn ty_layout(&self, ty: Ty) -> Result<Layout, Error> {
         let mut tables = self.0.borrow_mut();
-        let ty = ty.internal(&mut *tables);
+        let tcx = tables.tcx;
+        let ty = ty.internal(&mut *tables, tcx);
         let layout = tables.layout_of(ty)?.layout;
         Ok(layout.stable(&mut *tables))
     }
 
     fn layout_shape(&self, id: Layout) -> LayoutShape {
         let mut tables = self.0.borrow_mut();
-        id.internal(&mut *tables).0.stable(&mut *tables)
+        let tcx = tables.tcx;
+        id.internal(&mut *tables, tcx).0.stable(&mut *tables)
     }
 }
 
diff --git a/tests/ui-fulldeps/stable-mir/smir_internal.rs b/tests/ui-fulldeps/stable-mir/smir_internal.rs
index b4faaeb4fc06d..e23b0f6820a7d 100644
--- a/tests/ui-fulldeps/stable-mir/smir_internal.rs
+++ b/tests/ui-fulldeps/stable-mir/smir_internal.rs
@@ -26,11 +26,11 @@ use std::ops::ControlFlow;
 
 const CRATE_NAME: &str = "input";
 
-fn test_translation(_tcx: TyCtxt) -> ControlFlow<()> {
+fn test_translation(tcx: TyCtxt<'_>) -> ControlFlow<()> {
     let main_fn = stable_mir::entry_fn().unwrap();
     let body = main_fn.body();
     let orig_ty = body.locals()[0].ty;
-    let rustc_ty = rustc_internal::internal(&orig_ty);
+    let rustc_ty = rustc_internal::internal(tcx, &orig_ty);
     assert!(rustc_ty.is_unit());
     ControlFlow::Continue(())
 }

From 6cd6539026dbcd5a7ea85a51bd07770a716ed605 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Fri, 19 Jan 2024 10:17:29 +0000
Subject: [PATCH 06/12] Use the new `with_tables` everywhere

---
 .../rustc_smir/src/rustc_internal/internal.rs | 257 +++++++++---------
 compiler/rustc_smir/src/rustc_internal/mod.rs |  15 +-
 2 files changed, 127 insertions(+), 145 deletions(-)

diff --git a/compiler/rustc_smir/src/rustc_internal/internal.rs b/compiler/rustc_smir/src/rustc_internal/internal.rs
index 01260659fd53f..fa52f52d60b99 100644
--- a/compiler/rustc_smir/src/rustc_internal/internal.rs
+++ b/compiler/rustc_smir/src/rustc_internal/internal.rs
@@ -21,37 +21,37 @@ use stable_mir::{CrateItem, CrateNum, DefId};
 
 use super::RustcInternal;
 
-unsafe impl<'tcx> RustcInternal<'tcx> for CrateItem {
-    type T = rustc_span::def_id::DefId;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for CrateItem {
+    type T<'tcx> = rustc_span::def_id::DefId;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         self.0.internal(tables, tcx)
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for CrateNum {
-    type T = rustc_span::def_id::CrateNum;
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for CrateNum {
+    type T<'tcx> = rustc_span::def_id::CrateNum;
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         rustc_span::def_id::CrateNum::from_usize(*self)
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for DefId {
-    type T = rustc_span::def_id::DefId;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for DefId {
+    type T<'tcx> = rustc_span::def_id::DefId;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.lift(tables.def_ids[*self]).unwrap()
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for GenericArgs {
-    type T = rustc_ty::GenericArgsRef<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for GenericArgs {
+    type T<'tcx> = rustc_ty::GenericArgsRef<'tcx>;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.mk_args_from_iter(self.0.iter().map(|arg| arg.internal(tables, tcx)))
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for GenericArgKind {
-    type T = rustc_ty::GenericArg<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for GenericArgKind {
+    type T<'tcx> = rustc_ty::GenericArg<'tcx>;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         let arg: rustc_ty::GenericArg<'tcx> = match self {
             GenericArgKind::Lifetime(reg) => reg.internal(tables, tcx).into(),
             GenericArgKind::Type(ty) => ty.internal(tables, tcx).into(),
@@ -61,25 +61,25 @@ unsafe impl<'tcx> RustcInternal<'tcx> for GenericArgKind {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Region {
-    type T = rustc_ty::Region<'tcx>;
-    fn internal(&self, _tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for Region {
+    type T<'tcx> = rustc_ty::Region<'tcx>;
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         // Cannot recover region. Use erased for now.
         tcx.lifetimes.re_erased
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Ty {
-    type T = InternalTy<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for Ty {
+    type T<'tcx> = InternalTy<'tcx>;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.lift(tables.types[*self]).unwrap()
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for RigidTy {
-    type T = rustc_ty::TyKind<'tcx>;
+impl RustcInternal for RigidTy {
+    type T<'tcx> = rustc_ty::TyKind<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             RigidTy::Bool => rustc_ty::TyKind::Bool,
             RigidTy::Char => rustc_ty::TyKind::Char,
@@ -131,10 +131,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for RigidTy {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for IntTy {
-    type T = rustc_ty::IntTy;
+impl RustcInternal for IntTy {
+    type T<'tcx> = rustc_ty::IntTy;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             IntTy::Isize => rustc_ty::IntTy::Isize,
             IntTy::I8 => rustc_ty::IntTy::I8,
@@ -146,10 +146,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for IntTy {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for UintTy {
-    type T = rustc_ty::UintTy;
+impl RustcInternal for UintTy {
+    type T<'tcx> = rustc_ty::UintTy;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             UintTy::Usize => rustc_ty::UintTy::Usize,
             UintTy::U8 => rustc_ty::UintTy::U8,
@@ -161,10 +161,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for UintTy {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for FloatTy {
-    type T = rustc_ty::FloatTy;
+impl RustcInternal for FloatTy {
+    type T<'tcx> = rustc_ty::FloatTy;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             FloatTy::F32 => rustc_ty::FloatTy::F32,
             FloatTy::F64 => rustc_ty::FloatTy::F64,
@@ -172,10 +172,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for FloatTy {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Mutability {
-    type T = rustc_ty::Mutability;
+impl RustcInternal for Mutability {
+    type T<'tcx> = rustc_ty::Mutability;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             Mutability::Not => rustc_ty::Mutability::Not,
             Mutability::Mut => rustc_ty::Mutability::Mut,
@@ -183,10 +183,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for Mutability {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Movability {
-    type T = rustc_ty::Movability;
+impl RustcInternal for Movability {
+    type T<'tcx> = rustc_ty::Movability;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             Movability::Static => rustc_ty::Movability::Static,
             Movability::Movable => rustc_ty::Movability::Movable,
@@ -194,14 +194,12 @@ unsafe impl<'tcx> RustcInternal<'tcx> for Movability {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for FnSig {
-    type T = rustc_ty::FnSig<'tcx>;
+impl RustcInternal for FnSig {
+    type T<'tcx> = rustc_ty::FnSig<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.lift(rustc_ty::FnSig {
-            inputs_and_output: tables
-                .tcx
-                .mk_type_list(&self.inputs_and_output.internal(tables, tcx)),
+            inputs_and_output: tcx.mk_type_list(&self.inputs_and_output.internal(tables, tcx)),
             c_variadic: self.c_variadic,
             unsafety: self.unsafety.internal(tables, tcx),
             abi: self.abi.internal(tables, tcx),
@@ -210,25 +208,25 @@ unsafe impl<'tcx> RustcInternal<'tcx> for FnSig {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for VariantIdx {
-    type T = rustc_target::abi::VariantIdx;
+impl RustcInternal for VariantIdx {
+    type T<'tcx> = rustc_target::abi::VariantIdx;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         rustc_target::abi::VariantIdx::from(self.to_index())
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for VariantDef {
-    type T = &'tcx rustc_ty::VariantDef;
+impl RustcInternal for VariantDef {
+    type T<'tcx> = &'tcx rustc_ty::VariantDef;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         self.adt_def.internal(tables, tcx).variant(self.idx.internal(tables, tcx))
     }
 }
 
 fn ty_const<'tcx>(
     constant: &Const,
-    tables: &mut Tables<'tcx>,
+    tables: &mut Tables<'_>,
     tcx: TyCtxt<'tcx>,
 ) -> rustc_ty::Const<'tcx> {
     match constant.internal(tables, tcx) {
@@ -239,15 +237,15 @@ fn ty_const<'tcx>(
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Const {
-    type T = rustc_middle::mir::Const<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for Const {
+    type T<'tcx> = rustc_middle::mir::Const<'tcx>;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         let constant = tables.constants[self.id];
         match constant {
             rustc_middle::mir::Const::Ty(ty) => rustc_middle::mir::Const::Ty(tcx.lift(ty).unwrap()),
             rustc_middle::mir::Const::Unevaluated(uneval, ty) => {
                 rustc_middle::mir::Const::Unevaluated(
-                    lift_unevaluated(tcx, uneval),
+                    tcx.lift(uneval).unwrap(),
                     tcx.lift(ty).unwrap(),
                 )
             }
@@ -258,10 +256,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for Const {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for MonoItem {
-    type T = rustc_middle::mir::mono::MonoItem<'tcx>;
+impl RustcInternal for MonoItem {
+    type T<'tcx> = rustc_middle::mir::mono::MonoItem<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         use rustc_middle::mir::mono as rustc_mono;
         match self {
             MonoItem::Fn(instance) => rustc_mono::MonoItem::Fn(instance.internal(tables, tcx)),
@@ -273,31 +271,31 @@ unsafe impl<'tcx> RustcInternal<'tcx> for MonoItem {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Instance {
-    type T = rustc_ty::Instance<'tcx>;
+impl RustcInternal for Instance {
+    type T<'tcx> = rustc_ty::Instance<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.lift(tables.instances[self.def]).unwrap()
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for StaticDef {
-    type T = rustc_span::def_id::DefId;
+impl RustcInternal for StaticDef {
+    type T<'tcx> = rustc_span::def_id::DefId;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         self.0.internal(tables, tcx)
     }
 }
 
 #[allow(rustc::usage_of_qualified_ty)]
-unsafe impl<'tcx, T> RustcInternal<'tcx> for Binder<T>
+impl<T> RustcInternal for Binder<T>
 where
-    T: RustcInternal<'tcx>,
-    T::T: rustc_ty::TypeVisitable<rustc_ty::TyCtxt<'tcx>>,
+    T: RustcInternal,
+    for<'tcx> T::T<'tcx>: rustc_ty::TypeVisitable<rustc_ty::TyCtxt<'tcx>>,
 {
-    type T = rustc_ty::Binder<'tcx, T::T>;
+    type T<'tcx> = rustc_ty::Binder<'tcx, T::T<'tcx>>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         rustc_ty::Binder::bind_with_vars(
             self.value.internal(tables, tcx),
             tcx.mk_bound_variable_kinds_from_iter(
@@ -307,10 +305,10 @@ where
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for BoundVariableKind {
-    type T = rustc_ty::BoundVariableKind;
+impl RustcInternal for BoundVariableKind {
+    type T<'tcx> = rustc_ty::BoundVariableKind;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             BoundVariableKind::Ty(kind) => rustc_ty::BoundVariableKind::Ty(match kind {
                 BoundTyKind::Anon => rustc_ty::BoundTyKind::Anon,
@@ -332,10 +330,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for BoundVariableKind {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for DynKind {
-    type T = rustc_ty::DynKind;
+impl RustcInternal for DynKind {
+    type T<'tcx> = rustc_ty::DynKind;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             DynKind::Dyn => rustc_ty::DynKind::Dyn,
             DynKind::DynStar => rustc_ty::DynKind::DynStar,
@@ -343,10 +341,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for DynKind {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialPredicate {
-    type T = rustc_ty::ExistentialPredicate<'tcx>;
+impl RustcInternal for ExistentialPredicate {
+    type T<'tcx> = rustc_ty::ExistentialPredicate<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             ExistentialPredicate::Trait(trait_ref) => {
                 rustc_ty::ExistentialPredicate::Trait(trait_ref.internal(tables, tcx))
@@ -361,10 +359,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialPredicate {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialProjection {
-    type T = rustc_ty::ExistentialProjection<'tcx>;
+impl RustcInternal for ExistentialProjection {
+    type T<'tcx> = rustc_ty::ExistentialProjection<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         rustc_ty::ExistentialProjection {
             def_id: self.def_id.0.internal(tables, tcx),
             args: self.generic_args.internal(tables, tcx),
@@ -373,10 +371,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialProjection {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for TermKind {
-    type T = rustc_ty::Term<'tcx>;
+impl RustcInternal for TermKind {
+    type T<'tcx> = rustc_ty::Term<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             TermKind::Type(ty) => ty.internal(tables, tcx).into(),
             TermKind::Const(const_) => ty_const(const_, tables, tcx).into(),
@@ -384,10 +382,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for TermKind {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialTraitRef {
-    type T = rustc_ty::ExistentialTraitRef<'tcx>;
+impl RustcInternal for ExistentialTraitRef {
+    type T<'tcx> = rustc_ty::ExistentialTraitRef<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         rustc_ty::ExistentialTraitRef {
             def_id: self.def_id.0.internal(tables, tcx),
             args: self.generic_args.internal(tables, tcx),
@@ -395,10 +393,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for ExistentialTraitRef {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for TraitRef {
-    type T = rustc_ty::TraitRef<'tcx>;
+impl RustcInternal for TraitRef {
+    type T<'tcx> = rustc_ty::TraitRef<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         rustc_ty::TraitRef::new(
             tcx,
             self.def_id.0.internal(tables, tcx),
@@ -407,17 +405,17 @@ unsafe impl<'tcx> RustcInternal<'tcx> for TraitRef {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for AllocId {
-    type T = rustc_middle::mir::interpret::AllocId;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for AllocId {
+    type T<'tcx> = rustc_middle::mir::interpret::AllocId;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.lift(tables.alloc_ids[*self]).unwrap()
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for ClosureKind {
-    type T = rustc_ty::ClosureKind;
+impl RustcInternal for ClosureKind {
+    type T<'tcx> = rustc_ty::ClosureKind;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             ClosureKind::Fn => rustc_ty::ClosureKind::Fn,
             ClosureKind::FnMut => rustc_ty::ClosureKind::FnMut,
@@ -426,17 +424,17 @@ unsafe impl<'tcx> RustcInternal<'tcx> for ClosureKind {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for AdtDef {
-    type T = rustc_ty::AdtDef<'tcx>;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+impl RustcInternal for AdtDef {
+    type T<'tcx> = rustc_ty::AdtDef<'tcx>;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.adt_def(self.0.internal(tables, tcx))
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Abi {
-    type T = rustc_target::spec::abi::Abi;
+impl RustcInternal for Abi {
+    type T<'tcx> = rustc_target::spec::abi::Abi;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match *self {
             Abi::Rust => rustc_target::spec::abi::Abi::Rust,
             Abi::C { unwind } => rustc_target::spec::abi::Abi::C { unwind },
@@ -469,10 +467,10 @@ unsafe impl<'tcx> RustcInternal<'tcx> for Abi {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Safety {
-    type T = rustc_hir::Unsafety;
+impl RustcInternal for Safety {
+    type T<'tcx> = rustc_hir::Unsafety;
 
-    fn internal(&self, _tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         match self {
             Safety::Unsafe => rustc_hir::Unsafety::Unsafe,
             Safety::Normal => rustc_hir::Unsafety::Normal,
@@ -480,62 +478,51 @@ unsafe impl<'tcx> RustcInternal<'tcx> for Safety {
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Span {
-    type T = rustc_span::Span;
+impl RustcInternal for Span {
+    type T<'tcx> = rustc_span::Span;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, _tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tables[*self]
     }
 }
 
-unsafe impl<'tcx> RustcInternal<'tcx> for Layout {
-    type T = rustc_target::abi::Layout<'tcx>;
+impl RustcInternal for Layout {
+    type T<'tcx> = rustc_target::abi::Layout<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         tcx.lift(tables.layouts[*self]).unwrap()
     }
 }
 
-unsafe impl<'tcx, T> RustcInternal<'tcx> for &T
+impl<T> RustcInternal for &T
 where
-    T: RustcInternal<'tcx>,
+    T: RustcInternal,
 {
-    type T = T::T;
+    type T<'tcx> = T::T<'tcx>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         (*self).internal(tables, tcx)
     }
 }
 
-unsafe impl<'tcx, T> RustcInternal<'tcx> for Option<T>
+impl<T> RustcInternal for Option<T>
 where
-    T: RustcInternal<'tcx>,
+    T: RustcInternal,
 {
-    type T = Option<T::T>;
+    type T<'tcx> = Option<T::T<'tcx>>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         self.as_ref().map(|inner| inner.internal(tables, tcx))
     }
 }
 
-unsafe impl<'tcx, T> RustcInternal<'tcx> for Vec<T>
+impl<T> RustcInternal for Vec<T>
 where
-    T: RustcInternal<'tcx>,
+    T: RustcInternal,
 {
-    type T = Vec<T::T>;
+    type T<'tcx> = Vec<T::T<'tcx>>;
 
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T {
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
         self.iter().map(|e| e.internal(tables, tcx)).collect()
     }
 }
-
-fn lift_unevaluated<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    uneval: rustc_middle::mir::UnevaluatedConst<'tcx>,
-) -> rustc_middle::mir::UnevaluatedConst<'tcx> {
-    rustc_middle::mir::UnevaluatedConst {
-        def: uneval.def,
-        args: tcx.lift(uneval.args).unwrap(),
-        promoted: uneval.promoted,
-    }
-}
diff --git a/compiler/rustc_smir/src/rustc_internal/mod.rs b/compiler/rustc_smir/src/rustc_internal/mod.rs
index b17ad153ed5ba..43987fcf10fc9 100644
--- a/compiler/rustc_smir/src/rustc_internal/mod.rs
+++ b/compiler/rustc_smir/src/rustc_internal/mod.rs
@@ -50,9 +50,9 @@ pub fn stable<'tcx, S: Stable<'tcx>>(item: S) -> S::T {
 /// # Panics
 ///
 /// This function will panic if StableMIR has not been properly initialized.
-pub fn internal<'tcx, S>(tcx: TyCtxt<'tcx>, item: S) -> S::T
+pub fn internal<'tcx, S>(tcx: TyCtxt<'tcx>, item: S) -> S::T<'tcx>
 where
-    S: RustcInternal<'tcx>,
+    S: RustcInternal,
 {
     // The tcx argument ensures that the item won't outlive the type context.
     with_tables(|tables| item.internal(tables, tcx))
@@ -419,12 +419,7 @@ impl<K: PartialEq + Hash + Eq, V: Copy + Debug + PartialEq + IndexedVal> Index<V
 /// Trait used to translate a stable construct to its rustc counterpart.
 ///
 /// This is basically a mirror of [crate::rustc_smir::Stable].
-///
-/// # Safety
-///
-/// This trait is unsafe, and every implementation should ensure that their translation
-/// is lifted if necessary with the given type context (`tcx`).
-pub unsafe trait RustcInternal<'tcx> {
-    type T;
-    fn internal(&self, tables: &mut Tables<'tcx>, tcx: TyCtxt<'tcx>) -> Self::T;
+pub trait RustcInternal {
+    type T<'tcx>;
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx>;
 }

From 5796b3c16733f3d9cb2f3476ed1dc0fe05b14e25 Mon Sep 17 00:00:00 2001
From: The 8472 <git@infinite-source.de>
Date: Fri, 19 Jan 2024 22:42:52 +0100
Subject: [PATCH 07/12] fix: Drop guard was deallocating with the incorrect
 size

InPlaceDstBufDrop holds onto the allocation before the shrinking happens
which means it must deallocate the destination elements but the source
allocation.
---
 library/alloc/src/vec/in_place_collect.rs | 10 +++++----
 library/alloc/src/vec/in_place_drop.rs    | 26 ++++++++++++++++-------
 library/alloc/src/vec/mod.rs              |  2 +-
 3 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/library/alloc/src/vec/in_place_collect.rs b/library/alloc/src/vec/in_place_collect.rs
index ec5f32539f2c2..633ca8c99b408 100644
--- a/library/alloc/src/vec/in_place_collect.rs
+++ b/library/alloc/src/vec/in_place_collect.rs
@@ -72,7 +72,7 @@
 //! This is handled by the [`InPlaceDrop`] guard for sink items (`U`) and by
 //! [`vec::IntoIter::forget_allocation_drop_remaining()`] for remaining source items (`T`).
 //!
-//! If dropping any remaining source item (`T`) panics then [`InPlaceDstBufDrop`] will handle dropping
+//! If dropping any remaining source item (`T`) panics then [`InPlaceDstDataSrcBufDrop`] will handle dropping
 //! the already collected sink items (`U`) and freeing the allocation.
 //!
 //! [`vec::IntoIter::forget_allocation_drop_remaining()`]: super::IntoIter::forget_allocation_drop_remaining()
@@ -158,11 +158,12 @@ use crate::alloc::{handle_alloc_error, Global};
 use core::alloc::Allocator;
 use core::alloc::Layout;
 use core::iter::{InPlaceIterable, SourceIter, TrustedRandomAccessNoCoerce};
+use core::marker::PhantomData;
 use core::mem::{self, ManuallyDrop, SizedTypeProperties};
 use core::num::NonZeroUsize;
 use core::ptr::{self, NonNull};
 
-use super::{InPlaceDrop, InPlaceDstBufDrop, SpecFromIter, SpecFromIterNested, Vec};
+use super::{InPlaceDrop, InPlaceDstDataSrcBufDrop, SpecFromIter, SpecFromIterNested, Vec};
 
 const fn in_place_collectible<DEST, SRC>(
     step_merge: Option<NonZeroUsize>,
@@ -262,7 +263,7 @@ where
             );
         }
 
-        // The ownership of the allocation and the new `T` values is temporarily moved into `dst_guard`.
+        // The ownership of the source allocation and the new `T` values is temporarily moved into `dst_guard`.
         // This is safe because
         // * `forget_allocation_drop_remaining` immediately forgets the allocation
         // before any panic can occur in order to avoid any double free, and then proceeds to drop
@@ -273,7 +274,8 @@ where
         // Note: This access to the source wouldn't be allowed by the TrustedRandomIteratorNoCoerce
         // contract (used by SpecInPlaceCollect below). But see the "O(1) collect" section in the
         // module documentation why this is ok anyway.
-        let dst_guard = InPlaceDstBufDrop { ptr: dst_buf, len, cap: dst_cap };
+        let dst_guard =
+            InPlaceDstDataSrcBufDrop { ptr: dst_buf, len, src_cap, src: PhantomData::<I::Src> };
         src.forget_allocation_drop_remaining();
 
         // Adjust the allocation if the alignment didn't match or the source had a capacity in bytes
diff --git a/library/alloc/src/vec/in_place_drop.rs b/library/alloc/src/vec/in_place_drop.rs
index 25ca33c6a7bf0..40a540b57fc22 100644
--- a/library/alloc/src/vec/in_place_drop.rs
+++ b/library/alloc/src/vec/in_place_drop.rs
@@ -1,6 +1,10 @@
-use core::ptr::{self};
+use core::marker::PhantomData;
+use core::ptr::{self, drop_in_place};
 use core::slice::{self};
 
+use crate::alloc::Global;
+use crate::raw_vec::RawVec;
+
 // A helper struct for in-place iteration that drops the destination slice of iteration,
 // i.e. the head. The source slice (the tail) is dropped by IntoIter.
 pub(super) struct InPlaceDrop<T> {
@@ -23,17 +27,23 @@ impl<T> Drop for InPlaceDrop<T> {
     }
 }
 
-// A helper struct for in-place collection that drops the destination allocation and elements,
-// to avoid leaking them if some other destructor panics.
-pub(super) struct InPlaceDstBufDrop<T> {
-    pub(super) ptr: *mut T,
+// A helper struct for in-place collection that drops the destination items together with
+// the source allocation - i.e. before the reallocation happened - to avoid leaking them
+// if some other destructor panics.
+pub(super) struct InPlaceDstDataSrcBufDrop<Src, Dest> {
+    pub(super) ptr: *mut Dest,
     pub(super) len: usize,
-    pub(super) cap: usize,
+    pub(super) src_cap: usize,
+    pub(super) src: PhantomData<Src>,
 }
 
-impl<T> Drop for InPlaceDstBufDrop<T> {
+impl<Src, Dest> Drop for InPlaceDstDataSrcBufDrop<Src, Dest> {
     #[inline]
     fn drop(&mut self) {
-        unsafe { super::Vec::from_raw_parts(self.ptr, self.len, self.cap) };
+        unsafe {
+            let _drop_allocation =
+                RawVec::<Src>::from_raw_parts_in(self.ptr.cast::<Src>(), self.src_cap, Global);
+            drop_in_place(core::ptr::slice_from_raw_parts_mut::<Dest>(self.ptr, self.len));
+        };
     }
 }
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 35ea97bfe609c..48daec152286b 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -123,7 +123,7 @@ use self::set_len_on_drop::SetLenOnDrop;
 mod set_len_on_drop;
 
 #[cfg(not(no_global_oom_handling))]
-use self::in_place_drop::{InPlaceDrop, InPlaceDstBufDrop};
+use self::in_place_drop::{InPlaceDrop, InPlaceDstDataSrcBufDrop};
 
 #[cfg(not(no_global_oom_handling))]
 mod in_place_drop;

From 270f1510bebd3d7b1bb688283ee254a9a3988218 Mon Sep 17 00:00:00 2001
From: Georgiy Komarov <jubnzv@gmail.com>
Date: Sat, 20 Jan 2024 07:39:33 -0300
Subject: [PATCH 08/12] rustc_mir_dataflow: Add exports for external tools

Added back previously available exports:

* Forward/Backward: used when implementing `AnalysisDomain`
* Engine: used in user's code to solve the dataflow problem
* SwitchIntEdgeEffects: used when implementing functions of the `Analysis` trait
* graphviz: potentially useful for debugging purposes

These exports are used when implementing external tools based on MIR
dataflow framework.

Closes #120130
---
 compiler/rustc_mir_dataflow/src/lib.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_mir_dataflow/src/lib.rs b/compiler/rustc_mir_dataflow/src/lib.rs
index b805f8ca23eb4..637e6ca83ef52 100644
--- a/compiler/rustc_mir_dataflow/src/lib.rs
+++ b/compiler/rustc_mir_dataflow/src/lib.rs
@@ -21,10 +21,10 @@ pub use self::drop_flag_effects::{
     move_path_children_matching, on_all_children_bits, on_lookup_result_bits,
 };
 pub use self::framework::{
-    fmt, lattice, visit_results, Analysis, AnalysisDomain, Direction, GenKill, GenKillAnalysis,
-    JoinSemiLattice, MaybeReachable, Results, ResultsCursor, ResultsVisitable, ResultsVisitor,
+    fmt, graphviz, lattice, visit_results, Analysis, AnalysisDomain, Backward, Direction, Engine,
+    Forward, GenKill, GenKillAnalysis, JoinSemiLattice, MaybeReachable, Results, ResultsCursor,
+    ResultsVisitable, ResultsVisitor, SwitchIntEdgeEffects,
 };
-use self::framework::{Backward, SwitchIntEdgeEffects};
 use self::move_paths::MoveData;
 
 pub mod debuginfo;

From f6b3bcc4313b7d6c217a92f8e9615f0b136c9ab3 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 20 Jan 2024 09:47:53 -0800
Subject: [PATCH 09/12] Capture the rationale for -Zallow-features= in
 bootstrap.py

---
 src/bootstrap/bootstrap.py | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/bootstrap/bootstrap.py b/src/bootstrap/bootstrap.py
index 28d96cb1cfe56..83fdcddecf27a 100644
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -924,17 +924,29 @@ def build_bootstrap_cmd(self, env):
         # default toolchain is not nightly.
         #
         # But that setting has the collateral effect of rust-analyzer also
-        # passing RUSTC_BOOTSTRAP=1 to all x.py invocations too (the various overrideCommand).
-        # For compiling bootstrap that can cause spurious rebuilding of bootstrap when
-        # rust-analyzer x.py invocations are interleaved with handwritten ones on the
-        # command line.
+        # passing RUSTC_BOOTSTRAP=1 to all x.py invocations too (the various
+        # overrideCommand).
         #
-        # Set RUSTC_BOOTSTRAP=1 consistently.
+        # Set a consistent RUSTC_BOOTSTRAP=1 here to prevent spurious rebuilds
+        # of bootstrap when rust-analyzer x.py invocations are interleaved with
+        # handwritten ones on the command line.
         env["RUSTC_BOOTSTRAP"] = "1"
 
-        default_rustflags = "" if env.get("RUSTFLAGS_BOOTSTRAP", "") else "-Zallow-features="
-
-        env.setdefault("RUSTFLAGS", default_rustflags)
+        # If any of RUSTFLAGS or RUSTFLAGS_BOOTSTRAP are present and nonempty,
+        # we allow arbitrary compiler flags in there, including unstable ones
+        # such as `-Zthreads=8`.
+        #
+        # But if there aren't custom flags being passed to bootstrap, then we
+        # cancel the RUSTC_BOOTSTRAP=1 from above by passing `-Zallow-features=`
+        # to ensure unstable language or library features do not accidentally
+        # get introduced into bootstrap over time. Distros rely on being able to
+        # compile bootstrap with a variety of their toolchains, not necessarily
+        # the same as Rust's CI uses.
+        if env.get("RUSTFLAGS", "") or env.get("RUSTFLAGS_BOOTSTRAP", ""):
+            # Preserve existing RUSTFLAGS.
+            env.setdefault("RUSTFLAGS", "")
+        else:
+            env["RUSTFLAGS"] = "-Zallow-features="
 
         target_features = []
         if self.get_toml("crt-static", build_section) == "true":

From 7842043b992587505358540dd3dfe50684c13f5f Mon Sep 17 00:00:00 2001
From: Georgiy Komarov <jubnzv@gmail.com>
Date: Sat, 20 Jan 2024 16:52:18 -0300
Subject: [PATCH 10/12] Add a warning comment

---
 compiler/rustc_mir_dataflow/src/lib.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/compiler/rustc_mir_dataflow/src/lib.rs b/compiler/rustc_mir_dataflow/src/lib.rs
index 637e6ca83ef52..8d189babee891 100644
--- a/compiler/rustc_mir_dataflow/src/lib.rs
+++ b/compiler/rustc_mir_dataflow/src/lib.rs
@@ -16,6 +16,8 @@ extern crate rustc_middle;
 
 use rustc_middle::ty;
 
+// Please change the public `use` directives cautiously, as they might be used by external tools.
+// See issue #120130.
 pub use self::drop_flag_effects::{
     drop_flag_effects_for_function_entry, drop_flag_effects_for_location,
     move_path_children_matching, on_all_children_bits, on_lookup_result_bits,

From cc8e56b1e93ada97a32fa7b5c6482e1f20963ca6 Mon Sep 17 00:00:00 2001
From: Mark Rousskov <mark.simulacrum@gmail.com>
Date: Sat, 20 Jan 2024 16:22:02 -0500
Subject: [PATCH 11/12] Warn users about limited review for tier 2 and 3 code

---
 src/doc/rustc/src/platform-support.md | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index 2ddf5737fbd91..9e5c1ed87489e 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -72,6 +72,12 @@ ensure that each tier 2 target can be used as build target after each change. Au
 not always run so it's not guaranteed to produce a working build, but tier 2
 targets often work to quite a good degree and patches are always welcome!
 
+Tier 2 target-specific code is not closely scrutinized by Rust team(s) when
+modifications are made. Bugs are possible in all code, but the level of quality
+control for these targets is likely to be lower. See [library team
+policy](https://std-dev-guide.rust-lang.org/policy/target-code.html) for
+details on the review practices for standard library code.
+
 Tier 2 targets with host tools additionally support running tools like `rustc`
 and `cargo` natively on the target, and automated builds ensure that the host
 tools build as well. This allows the target to be used as a development
@@ -121,6 +127,12 @@ The `std` column in the table below has the following meanings:
 
 [`no_std`]: https://rust-embedded.github.io/book/intro/no-std.html
 
+Tier 2 target-specific code is not closely scrutinized by Rust team(s) when
+modifications are made. Bugs are possible in all code, but the level of quality
+control for these targets is likely to be lower. See [library team
+policy](https://std-dev-guide.rust-lang.org/policy/target-code.html) for
+details on the review practices for standard library code.
+
 **NOTE:** The `rust-docs` component is not usually built for tier 2 targets,
 so Rustup may install the documentation for a similar tier 1 target instead.
 
@@ -211,6 +223,12 @@ The `std` column in the table below has the following meanings:
 
 [`no_std`]: https://rust-embedded.github.io/book/intro/no-std.html
 
+Tier 3 target-specific code is not closely scrutinized by Rust team(s) when
+modifications are made. Bugs are possible in all code, but the level of quality
+control for these targets is likely to be lower. See [library team
+policy](https://std-dev-guide.rust-lang.org/policy/target-code.html) for
+details on the review practices for standard library code.
+
 The `host` column indicates whether the codebase includes support for building
 host tools.
 

From 6f1944d394923fcc88a02f46de5258a36896e99e Mon Sep 17 00:00:00 2001
From: Zalathar <Zalathar@users.noreply.github.com>
Date: Sun, 21 Jan 2024 11:55:04 +1100
Subject: [PATCH 12/12] Document some alternatives to `Vec::split_off`

---
 library/alloc/src/vec/mod.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 35ea97bfe609c..fe835a8ba4045 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -2167,6 +2167,12 @@ impl<T, A: Allocator> Vec<T, A> {
     /// `[at, len)`. After the call, the original vector will be left containing
     /// the elements `[0, at)` with its previous capacity unchanged.
     ///
+    /// - If you want to take ownership of the entire contents and capacity of
+    ///   the vector, see [`mem::take`] or [`mem::replace`].
+    /// - If you don't need the returned vector at all, see [`Vec::truncate`].
+    /// - If you want to take ownership of an arbitrary subslice, or you don't
+    ///   necessarily want to store the removed items in a vector, see [`Vec::drain`].
+    ///
     /// # Panics
     ///
     /// Panics if `at > len`.