diff --git a/compiler/rustc_index/Cargo.toml b/compiler/rustc_index/Cargo.toml
index d8ea5aa80b87..e1cda5a9edda 100644
--- a/compiler/rustc_index/Cargo.toml
+++ b/compiler/rustc_index/Cargo.toml
@@ -7,6 +7,10 @@ edition = "2021"
 
 [dependencies]
 arrayvec = { version = "0.7", default-features = false }
-rustc_serialize = { path = "../rustc_serialize" }
-rustc_macros = { path = "../rustc_macros" }
+rustc_serialize = { path = "../rustc_serialize", optional = true }
+rustc_macros = { path = "../rustc_macros", optional = true }
 smallvec = "1.8.1"
+
+[features]
+default = ["nightly"]
+nightly = ["rustc_serialize", "rustc_macros"]
diff --git a/compiler/rustc_index/src/lib.rs b/compiler/rustc_index/src/lib.rs
index 23a4c1f06966..03d8ee139188 100644
--- a/compiler/rustc_index/src/lib.rs
+++ b/compiler/rustc_index/src/lib.rs
@@ -1,17 +1,20 @@
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
-#![feature(allow_internal_unstable)]
-#![feature(extend_one)]
-#![feature(min_specialization)]
-#![feature(new_uninit)]
-#![feature(step_trait)]
-#![feature(stmt_expr_attributes)]
-#![feature(test)]
+#![cfg_attr(feature = "nightly", feature(allow_internal_unstable))]
+#![cfg_attr(feature = "nightly", feature(extend_one))]
+#![cfg_attr(feature = "nightly", feature(min_specialization))]
+#![cfg_attr(feature = "nightly", feature(new_uninit))]
+#![cfg_attr(feature = "nightly", feature(step_trait))]
+#![cfg_attr(feature = "nightly", feature(stmt_expr_attributes))]
+#![cfg_attr(feature = "nightly", feature(test))]
 
+#[cfg(feature = "nightly")]
 pub mod bit_set;
+#[cfg(feature = "nightly")]
 pub mod interval;
 pub mod vec;
 
+#[cfg(feature = "rustc_macros")]
 pub use rustc_macros::newtype_index;
 
 /// Type size assertion. The first argument is a type and the second argument is its expected size.
diff --git a/compiler/rustc_index/src/vec.rs b/compiler/rustc_index/src/vec.rs
index 1519258c7943..39aa27a23c1d 100644
--- a/compiler/rustc_index/src/vec.rs
+++ b/compiler/rustc_index/src/vec.rs
@@ -1,3 +1,4 @@
+#[cfg(feature = "rustc_serialize")]
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 
 use std::fmt;
@@ -61,12 +62,14 @@ pub struct IndexVec<I: Idx, T> {
 // not the phantom data.
 unsafe impl<I: Idx, T> Send for IndexVec<I, T> where T: Send {}
 
+#[cfg(feature = "rustc_serialize")]
 impl<S: Encoder, I: Idx, T: Encodable<S>> Encodable<S> for IndexVec<I, T> {
     fn encode(&self, s: &mut S) {
         Encodable::encode(&self.raw, s);
     }
 }
 
+#[cfg(feature = "rustc_serialize")]
 impl<D: Decoder, I: Idx, T: Decodable<D>> Decodable<D> for IndexVec<I, T> {
     fn decode(d: &mut D) -> Self {
         IndexVec { raw: Decodable::decode(d), _marker: PhantomData }
@@ -359,11 +362,13 @@ impl<I: Idx, T> Extend<T> for IndexVec<I, T> {
     }
 
     #[inline]
+    #[cfg(feature = "nightly")]
     fn extend_one(&mut self, item: T) {
         self.raw.push(item);
     }
 
     #[inline]
+    #[cfg(feature = "nightly")]
     fn extend_reserve(&mut self, additional: usize) {
         self.raw.reserve(additional);
     }
diff --git a/compiler/rustc_middle/src/arena.rs b/compiler/rustc_middle/src/arena.rs
index f8aae86fe3dc..7bd4b6c0c276 100644
--- a/compiler/rustc_middle/src/arena.rs
+++ b/compiler/rustc_middle/src/arena.rs
@@ -6,7 +6,7 @@
 macro_rules! arena_types {
     ($macro:path) => (
         $macro!([
-            [] layout: rustc_target::abi::LayoutS<'tcx>,
+            [] layout: rustc_target::abi::LayoutS<rustc_target::abi::VariantIdx>,
             [] fn_abi: rustc_target::abi::call::FnAbi<'tcx, rustc_middle::ty::Ty<'tcx>>,
             // AdtDef are interned and compared by address
             [decode] adt_def: rustc_middle::ty::AdtDefData,
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 26d30308ed37..f298e44e0893 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -148,7 +148,7 @@ pub struct CtxtInterners<'tcx> {
     const_: InternedSet<'tcx, ConstS<'tcx>>,
     const_allocation: InternedSet<'tcx, Allocation>,
     bound_variable_kinds: InternedSet<'tcx, List<ty::BoundVariableKind>>,
-    layout: InternedSet<'tcx, LayoutS<'tcx>>,
+    layout: InternedSet<'tcx, LayoutS<VariantIdx>>,
     adt_def: InternedSet<'tcx, AdtDefData>,
 }
 
@@ -2244,7 +2244,7 @@ direct_interners! {
     region: mk_region(RegionKind<'tcx>): Region -> Region<'tcx>,
     const_: mk_const_internal(ConstS<'tcx>): Const -> Const<'tcx>,
     const_allocation: intern_const_alloc(Allocation): ConstAllocation -> ConstAllocation<'tcx>,
-    layout: intern_layout(LayoutS<'tcx>): Layout -> Layout<'tcx>,
+    layout: intern_layout(LayoutS<VariantIdx>): Layout -> Layout<'tcx>,
     adt_def: intern_adt_def(AdtDefData): AdtDef -> AdtDef<'tcx>,
 }
 
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index c74d6bc3774a..fea2aa8cbf82 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -610,7 +610,7 @@ where
                 })
             }
 
-            Variants::Multiple { ref variants, .. } => variants[variant_index],
+            Variants::Multiple { ref variants, .. } => cx.tcx().intern_layout(variants[variant_index].clone()),
         };
 
         assert_eq!(*layout.variants(), Variants::Single { index: variant_index });
diff --git a/compiler/rustc_target/Cargo.toml b/compiler/rustc_target/Cargo.toml
index fc37fdb1c43c..58eb4f69c44f 100644
--- a/compiler/rustc_target/Cargo.toml
+++ b/compiler/rustc_target/Cargo.toml
@@ -7,9 +7,20 @@ edition = "2021"
 bitflags = "1.2.1"
 tracing = "0.1"
 serde_json = "1.0.59"
-rustc_data_structures = { path = "../rustc_data_structures" }
-rustc_feature = { path = "../rustc_feature" }
-rustc_index = { path = "../rustc_index" }
-rustc_macros = { path = "../rustc_macros" }
-rustc_serialize = { path = "../rustc_serialize" }
-rustc_span = { path = "../rustc_span" }
+rustc_data_structures = { path = "../rustc_data_structures", optional = true  }
+rustc_feature = { path = "../rustc_feature", optional = true }
+rustc_index = { path = "../rustc_index", default-features = false }
+rustc_macros = { path = "../rustc_macros", optional = true }
+rustc_serialize = { path = "../rustc_serialize", optional = true  }
+rustc_span = { path = "../rustc_span", optional = true }
+
+[features]
+default = ["nightly"]
+nightly = [
+    "rustc_data_structures",
+    "rustc_feature",
+    "rustc_index/nightly",
+    "rustc_macros",
+    "rustc_serialize",
+    "rustc_span",
+]
\ No newline at end of file
diff --git a/compiler/rustc_target/src/abi/mod.rs b/compiler/rustc_target/src/abi/mod.rs
index decbefc2f7c6..fa6af2ed7f3a 100644
--- a/compiler/rustc_target/src/abi/mod.rs
+++ b/compiler/rustc_target/src/abi/mod.rs
@@ -2,23 +2,29 @@ pub use Integer::*;
 pub use Primitive::*;
 
 use crate::json::{Json, ToJson};
+#[cfg(feature = "nightly")]
 use crate::spec::Target;
 
 use std::convert::{TryFrom, TryInto};
 use std::fmt;
+#[cfg(feature = "nightly")]
 use std::iter::Step;
 use std::num::{NonZeroUsize, ParseIntError};
 use std::ops::{Add, AddAssign, Deref, Mul, RangeInclusive, Sub};
 use std::str::FromStr;
 
+#[cfg(feature = "nightly")]
 use rustc_data_structures::intern::Interned;
 use rustc_index::vec::{Idx, IndexVec};
+#[cfg(feature = "nightly")]
 use rustc_macros::HashStable_Generic;
 
+#[cfg(feature = "nightly")]
 pub mod call;
 
 /// Parsed [Data layout](https://llvm.org/docs/LangRef.html#data-layout)
 /// for a target, which contains everything needed to compute layouts.
+#[derive(Debug, PartialEq, Eq)]
 pub struct TargetDataLayout {
     pub endian: Endian,
     pub i1_align: AbiAndPrefAlign,
@@ -80,6 +86,7 @@ pub enum TargetDataLayoutErrors<'a> {
 }
 
 impl TargetDataLayout {
+    #[cfg(feature = "nightly")]
     pub fn parse<'a>(target: &'a Target) -> Result<TargetDataLayout, TargetDataLayoutErrors<'a>> {
         // Parse an address space index from a string.
         let parse_address_space = |s: &'a str, cause: &'a str| {
@@ -248,7 +255,7 @@ impl HasDataLayout for TargetDataLayout {
 }
 
 /// Endianness of the target, which must match cfg(target-endian).
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, Eq)]
 pub enum Endian {
     Little,
     Big,
@@ -288,8 +295,8 @@ impl ToJson for Endian {
 }
 
 /// Size of a type in bytes.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable)]
-#[derive(HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[cfg_attr(feature = "nightly", derive(Encodable, Decodable, HashStable_Generic))]
 pub struct Size {
     raw: u64,
 }
@@ -466,6 +473,7 @@ impl AddAssign for Size {
     }
 }
 
+#[cfg(feature = "nightly")]
 impl Step for Size {
     #[inline]
     fn steps_between(start: &Self, end: &Self) -> Option<usize> {
@@ -504,8 +512,8 @@ impl Step for Size {
 }
 
 /// Alignment of a type in bytes (always a power of two).
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable)]
-#[derive(HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[cfg_attr(feature = "nightly", derive(Encodable, Decodable, HashStable_Generic))]
 pub struct Align {
     pow2: u8,
 }
@@ -588,7 +596,8 @@ impl Align {
 
 /// A pair of alignments, ABI-mandated and preferred.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-#[derive(HashStable_Generic)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+
 pub struct AbiAndPrefAlign {
     pub abi: Align,
     pub pref: Align,
@@ -612,7 +621,9 @@ impl AbiAndPrefAlign {
 }
 
 /// Integers, also used for enum discriminants.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+
 pub enum Integer {
     I8,
     I16,
@@ -710,7 +721,8 @@ impl Integer {
 }
 
 /// Fundamental unit of memory access and layout.
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub enum Primitive {
     /// The `bool` is the signedness of the `Integer` type.
     ///
@@ -777,7 +789,7 @@ impl Primitive {
 ///
 /// This is intended specifically to mirror LLVM’s `!range` metadata semantics.
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
-#[derive(HashStable_Generic)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub struct WrappingRange {
     pub start: u128,
     pub end: u128,
@@ -834,7 +846,7 @@ impl fmt::Debug for WrappingRange {
 
 /// Information about one scalar component of a Rust type.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
-#[derive(HashStable_Generic)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub enum Scalar {
     Initialized {
         value: Primitive,
@@ -924,7 +936,8 @@ impl Scalar {
 }
 
 /// Describes how the fields of a type are located in memory.
-#[derive(PartialEq, Eq, Hash, Debug, HashStable_Generic)]
+#[derive(PartialEq, Eq, Hash, Clone, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub enum FieldsShape {
     /// Scalar primitives and `!`, which never have fields.
     Primitive,
@@ -1058,7 +1071,9 @@ impl AddressSpace {
 
 /// Describes how values of the type are passed by target ABIs,
 /// in terms of categories of C types there are ABI rules for.
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+
 pub enum Abi {
     Uninhabited,
     Scalar(Scalar),
@@ -1113,16 +1128,18 @@ impl Abi {
     }
 }
 
+#[cfg(feature = "nightly")]
 rustc_index::newtype_index! {
     pub struct VariantIdx {
         derive [HashStable_Generic]
     }
 }
 
-#[derive(PartialEq, Eq, Hash, Debug, HashStable_Generic)]
-pub enum Variants<'a> {
+#[derive(PartialEq, Eq, Hash, Clone, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+pub enum Variants<V: Idx> {
     /// Single enum variants, structs/tuples, unions, and all non-ADTs.
-    Single { index: VariantIdx },
+    Single { index: V },
 
     /// Enum-likes with more than one inhabited variant: each variant comes with
     /// a *discriminant* (usually the same as the variant index but the user can
@@ -1132,14 +1149,15 @@ pub enum Variants<'a> {
     /// For enums, the tag is the sole field of the layout.
     Multiple {
         tag: Scalar,
-        tag_encoding: TagEncoding,
+        tag_encoding: TagEncoding<V>,
         tag_field: usize,
-        variants: IndexVec<VariantIdx, Layout<'a>>,
+        variants: IndexVec<V, LayoutS<V>>,
     },
 }
 
-#[derive(PartialEq, Eq, Hash, Debug, HashStable_Generic)]
-pub enum TagEncoding {
+#[derive(PartialEq, Eq, Hash, Clone, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+pub enum TagEncoding<V: Idx> {
     /// The tag directly stores the discriminant, but possibly with a smaller layout
     /// (so converting the tag to the discriminant can require sign extension).
     Direct,
@@ -1155,13 +1173,15 @@ pub enum TagEncoding {
     /// `None` has a null pointer for the second tuple field, and
     /// `Some` is the identity function (with a non-null reference).
     Niche {
-        untagged_variant: VariantIdx,
-        niche_variants: RangeInclusive<VariantIdx>,
+        untagged_variant: V,
+        #[cfg(feature = "nightly")]
+        niche_variants: RangeInclusive<V>,
         niche_start: u128,
     },
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub struct Niche {
     pub offset: Size,
     pub value: Primitive,
@@ -1244,8 +1264,9 @@ impl Niche {
     }
 }
 
-#[derive(PartialEq, Eq, Hash, HashStable_Generic)]
-pub struct LayoutS<'a> {
+#[derive(PartialEq, Eq, Hash, Clone)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+pub struct LayoutS<V: Idx> {
     /// Says where the fields are located within the layout.
     pub fields: FieldsShape,
 
@@ -1256,7 +1277,7 @@ pub struct LayoutS<'a> {
     ///
     /// To access all fields of this layout, both `fields` and the fields of the active variant
     /// must be taken into account.
-    pub variants: Variants<'a>,
+    pub variants: Variants<V>,
 
     /// The `abi` defines how this data is passed between functions, and it defines
     /// value restrictions via `valid_range`.
@@ -1275,13 +1296,13 @@ pub struct LayoutS<'a> {
     pub size: Size,
 }
 
-impl<'a> LayoutS<'a> {
+impl<V: Idx> LayoutS<V> {
     pub fn scalar<C: HasDataLayout>(cx: &C, scalar: Scalar) -> Self {
         let largest_niche = Niche::from_scalar(cx, Size::ZERO, scalar);
         let size = scalar.size(cx);
         let align = scalar.align(cx);
         LayoutS {
-            variants: Variants::Single { index: VariantIdx::new(0) },
+            variants: Variants::Single { index: V::new(0) },
             fields: FieldsShape::Primitive,
             abi: Abi::Scalar(scalar),
             largest_niche,
@@ -1289,9 +1310,39 @@ impl<'a> LayoutS<'a> {
             align,
         }
     }
+
+    #[inline]
+    pub fn fields(&self) -> &FieldsShape {
+        &self.fields
+    }
+
+    #[inline]
+    pub fn variants(&self) -> &Variants<V> {
+        &self.variants
+    }
+
+    #[inline]
+    pub fn abi(&self) -> Abi {
+        self.abi
+    }
+
+    #[inline]
+    pub fn largest_niche(&self) -> Option<Niche> {
+        self.largest_niche
+    }
+
+    #[inline]
+    pub fn align(&self) -> AbiAndPrefAlign {
+        self.align
+    }
+
+    #[inline]
+    pub fn size(&self) -> Size {
+        self.size
+    }
 }
 
-impl<'a> fmt::Debug for LayoutS<'a> {
+impl<V: Idx> fmt::Debug for LayoutS<V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // This is how `Layout` used to print before it become
         // `Interned<LayoutS>`. We print it like this to avoid having to update
@@ -1308,10 +1359,12 @@ impl<'a> fmt::Debug for LayoutS<'a> {
     }
 }
 
+#[cfg(feature = "nightly")]
 #[derive(Copy, Clone, PartialEq, Eq, Hash, HashStable_Generic)]
 #[rustc_pass_by_value]
-pub struct Layout<'a>(pub Interned<'a, LayoutS<'a>>);
+pub struct Layout<'a>(pub Interned<'a, LayoutS<VariantIdx>>);
 
+#[cfg(feature = "nightly")]
 impl<'a> fmt::Debug for Layout<'a> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // See comment on `<LayoutS as Debug>::fmt` above.
@@ -1319,12 +1372,13 @@ impl<'a> fmt::Debug for Layout<'a> {
     }
 }
 
+#[cfg(feature = "nightly")]
 impl<'a> Layout<'a> {
     pub fn fields(self) -> &'a FieldsShape {
         &self.0.0.fields
     }
 
-    pub fn variants(self) -> &'a Variants<'a> {
+    pub fn variants(self) -> &'a Variants<VariantIdx> {
         &self.0.0.variants
     }
 
@@ -1352,15 +1406,18 @@ impl<'a> Layout<'a> {
 /// to that obtained from `layout_of(ty)`, as we need to produce
 /// layouts for which Rust types do not exist, such as enum variants
 /// or synthetic fields of enums (i.e., discriminants) and fat pointers.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable_Generic)]
+#[cfg(feature = "nightly")]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub struct TyAndLayout<'a, Ty> {
     pub ty: Ty,
     pub layout: Layout<'a>,
 }
 
+#[cfg(feature = "nightly")]
 impl<'a, Ty> Deref for TyAndLayout<'a, Ty> {
-    type Target = &'a LayoutS<'a>;
-    fn deref(&self) -> &&'a LayoutS<'a> {
+    type Target = &'a LayoutS<VariantIdx>;
+    fn deref(&self) -> &&'a LayoutS<VariantIdx> {
         &self.layout.0.0
     }
 }
@@ -1402,6 +1459,7 @@ pub enum InitKind {
 
 /// Trait that needs to be implemented by the higher-level type representation
 /// (e.g. `rustc_middle::ty::Ty`), to provide `rustc_target::abi` functionality.
+#[cfg(feature = "nightly")]
 pub trait TyAbiInterface<'a, C>: Sized {
     fn ty_and_layout_for_variant(
         this: TyAndLayout<'a, Self>,
@@ -1420,6 +1478,7 @@ pub trait TyAbiInterface<'a, C>: Sized {
     fn is_unit(this: TyAndLayout<'a, Self>) -> bool;
 }
 
+#[cfg(feature = "nightly")]
 impl<'a, Ty> TyAndLayout<'a, Ty> {
     pub fn for_variant<C>(self, cx: &C, variant_index: VariantIdx) -> Self
     where
@@ -1489,7 +1548,7 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
     }
 }
 
-impl<'a, Ty> TyAndLayout<'a, Ty> {
+impl<V: Idx> LayoutS<V> {
     /// Returns `true` if the layout corresponds to an unsized type.
     pub fn is_unsized(&self) -> bool {
         self.abi.is_unsized()
diff --git a/compiler/rustc_target/src/lib.rs b/compiler/rustc_target/src/lib.rs
index aaba0d7f093a..1065980a26ac 100644
--- a/compiler/rustc_target/src/lib.rs
+++ b/compiler/rustc_target/src/lib.rs
@@ -8,13 +8,13 @@
 //! LLVM.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
-#![feature(assert_matches)]
-#![feature(associated_type_bounds)]
-#![feature(exhaustive_patterns)]
-#![feature(min_specialization)]
-#![feature(never_type)]
-#![feature(rustc_attrs)]
-#![feature(step_trait)]
+#![cfg_attr(feature = "nightly", feature(assert_matches))]
+#![cfg_attr(feature = "nightly", feature(associated_type_bounds))]
+#![cfg_attr(feature = "nightly", feature(exhaustive_patterns))]
+#![cfg_attr(feature = "nightly", feature(min_specialization))]
+#![cfg_attr(feature = "nightly", feature(never_type))]
+#![cfg_attr(feature = "nightly", feature(rustc_attrs))]
+#![cfg_attr(feature = "nightly", feature(step_trait))]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
@@ -22,14 +22,18 @@ use std::iter::FromIterator;
 use std::path::{Path, PathBuf};
 
 #[macro_use]
+#[cfg(feature = "nightly")]
 extern crate rustc_macros;
 
 #[macro_use]
+#[cfg(feature = "nightly")]
 extern crate tracing;
 
 pub mod abi;
+#[cfg(feature = "nightly")]
 pub mod asm;
 pub mod json;
+#[cfg(feature = "nightly")]
 pub mod spec;
 
 #[cfg(test)]
diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs
index 07af3dc51647..5e77ad4054a5 100644
--- a/compiler/rustc_ty_utils/src/layout.rs
+++ b/compiler/rustc_ty_utils/src/layout.rs
@@ -89,7 +89,11 @@ fn invert_mapping(map: &[u32]) -> Vec<u32> {
     inverse
 }
 
-fn scalar_pair<'tcx>(cx: &LayoutCx<'tcx, TyCtxt<'tcx>>, a: Scalar, b: Scalar) -> LayoutS<'tcx> {
+fn scalar_pair<'tcx>(
+    cx: &LayoutCx<'tcx, TyCtxt<'tcx>>,
+    a: Scalar,
+    b: Scalar,
+) -> LayoutS<VariantIdx> {
     let dl = cx.data_layout();
     let b_align = b.align(dl);
     let align = a.align(dl).max(b_align).max(dl.aggregate_align);
@@ -122,7 +126,7 @@ fn univariant_uninterned<'tcx>(
     fields: &[TyAndLayout<'_>],
     repr: &ReprOptions,
     kind: StructKind,
-) -> Result<LayoutS<'tcx>, LayoutError<'tcx>> {
+) -> Result<LayoutS<VariantIdx>, LayoutError<'tcx>> {
     let dl = cx.data_layout();
     let pack = repr.pack;
     if pack.is_some() && repr.align.is_some() {
@@ -864,13 +868,13 @@ fn layout_of_uncached<'tcx>(
             // variant layouts, so we can't store them in the
             // overall LayoutS. Store the overall LayoutS
             // and the variant LayoutSs here until then.
-            struct TmpLayout<'tcx> {
-                layout: LayoutS<'tcx>,
-                variants: IndexVec<VariantIdx, LayoutS<'tcx>>,
+            struct TmpLayout {
+                layout: LayoutS<VariantIdx>,
+                variants: IndexVec<VariantIdx, LayoutS<VariantIdx>>,
             }
 
             let calculate_niche_filling_layout =
-                || -> Result<Option<TmpLayout<'tcx>>, LayoutError<'tcx>> {
+                || -> Result<Option<TmpLayout>, LayoutError<'tcx>> {
                     // The current code for niche-filling relies on variant indices
                     // instead of actual discriminants, so enums with
                     // explicit discriminants (RFC #2363) would misbehave.
@@ -1317,7 +1321,7 @@ fn layout_of_uncached<'tcx>(
                     // pick the layout with the larger niche; otherwise,
                     // pick tagged as it has simpler codegen.
                     use Ordering::*;
-                    let niche_size = |tmp_l: &TmpLayout<'_>| {
+                    let niche_size = |tmp_l: &TmpLayout| {
                         tmp_l.layout.largest_niche.map_or(0, |n| n.available(dl))
                     };
                     match (
@@ -1338,11 +1342,7 @@ fn layout_of_uncached<'tcx>(
                     tag,
                     tag_encoding,
                     tag_field,
-                    variants: best_layout
-                        .variants
-                        .into_iter()
-                        .map(|layout| tcx.intern_layout(layout))
-                        .collect(),
+                    variants: best_layout.variants,
                 },
                 _ => bug!(),
             };
@@ -1657,7 +1657,7 @@ fn generator_layout<'tcx>(
 
             size = size.max(variant.size);
             align = align.max(variant.align);
-            Ok(tcx.intern_layout(variant))
+            Ok(variant)
         })
         .collect::<Result<IndexVec<VariantIdx, _>, _>>()?;
 
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 0f9b3b15c77f..daaeee9e84b6 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -10,7 +10,7 @@ use rustc_middle::ty::layout::LayoutError;
 use rustc_middle::ty::{self, Adt, TyCtxt};
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Symbol};
-use rustc_target::abi::{Layout, Primitive, TagEncoding, Variants};
+use rustc_target::abi::{LayoutS, Primitive, TagEncoding, VariantIdx, Variants};
 use std::cmp::Ordering;
 use std::fmt;
 use std::rc::Rc;
@@ -1892,7 +1892,7 @@ fn document_non_exhaustive(w: &mut Buffer, item: &clean::Item) {
 }
 
 fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
-    fn write_size_of_layout(w: &mut Buffer, layout: Layout<'_>, tag_size: u64) {
+    fn write_size_of_layout(w: &mut Buffer, layout: &LayoutS<VariantIdx>, tag_size: u64) {
         if layout.abi().is_unsized() {
             write!(w, "(unsized)");
         } else {
@@ -1927,7 +1927,7 @@ fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
                  chapter for details on type layout guarantees.</p></div>"
             );
             w.write_str("<p><strong>Size:</strong> ");
-            write_size_of_layout(w, ty_layout.layout, 0);
+            write_size_of_layout(w, &ty_layout.layout.0, 0);
             writeln!(w, "</p>");
             if let Variants::Multiple { variants, tag, tag_encoding, .. } =
                 &ty_layout.layout.variants()
@@ -1953,7 +1953,7 @@ fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
                     for (index, layout) in variants.iter_enumerated() {
                         let name = adt.variant(index).name;
                         write!(w, "<li><code>{name}</code>: ", name = name);
-                        write_size_of_layout(w, *layout, tag_size);
+                        write_size_of_layout(w, layout, tag_size);
                         writeln!(w, "</li>");
                     }
                     w.write_str("</ul>");