diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs
index 6740001c38be1..428191bc8b934 100644
--- a/compiler/rustc_abi/src/lib.rs
+++ b/compiler/rustc_abi/src/lib.rs
@@ -1057,6 +1057,32 @@ impl Scalar {
     }
 }
 
+rustc_index::newtype_index! {
+    /// The *source-order* index of a field in a variant.
+    ///
+    /// This is how most code after type checking refers to fields, rather than
+    /// using names (as names have hygiene complications and more complex lookup).
+    ///
+    /// Particularly for `repr(Rust)` types, this may not be the same as *layout* order.
+    /// (It is for `repr(C)` `struct`s, however.)
+    ///
+    /// For example, in the following types,
+    /// ```rust
+    /// # enum Never {}
+    /// # #[repr(u16)]
+    /// enum Demo1 {
+    ///    Variant0 { a: Never, b: i32 } = 100,
+    ///    Variant1 { c: u8, d: u64 } = 10,
+    /// }
+    /// struct Demo2 { e: u8, f: u16, g: u8 }
+    /// ```
+    /// `b` is `FieldIdx(1)` in `VariantIdx(0)`,
+    /// `d` is `FieldIdx(1)` in `VariantIdx(1)`, and
+    /// `f` is `FieldIdx(1)` in `VariantIdx(0)`.
+    #[derive(HashStable_Generic)]
+    pub struct FieldIdx {}
+}
+
 /// Describes how the fields of a type are located in memory.
 #[derive(PartialEq, Eq, Hash, Clone, Debug)]
 #[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index 9f543b71c5fa4..5827fa81cffb5 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -9,15 +9,15 @@ use rustc_hir::GeneratorKind;
 use rustc_infer::infer::{LateBoundRegionConversionTime, TyCtxtInferExt};
 use rustc_middle::mir::tcx::PlaceTy;
 use rustc_middle::mir::{
-    AggregateKind, Constant, FakeReadCause, Field, Local, LocalInfo, LocalKind, Location, Operand,
-    Place, PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
+    AggregateKind, Constant, FakeReadCause, Local, LocalInfo, LocalKind, Location, Operand, Place,
+    PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
 };
 use rustc_middle::ty::print::Print;
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_mir_dataflow::move_paths::{InitLocation, LookupResult};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{symbol::sym, Span, Symbol, DUMMY_SP};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{
     type_known_to_meet_bound_modulo_regions, Obligation, ObligationCause,
@@ -302,7 +302,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     fn describe_field(
         &self,
         place: PlaceRef<'tcx>,
-        field: Field,
+        field: FieldIdx,
         including_tuple_field: IncludingTupleField,
     ) -> Option<String> {
         let place_ty = match place {
@@ -331,7 +331,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     fn describe_field_from_ty(
         &self,
         ty: Ty<'_>,
-        field: Field,
+        field: FieldIdx,
         variant_index: Option<VariantIdx>,
         including_tuple_field: IncludingTupleField,
     ) -> Option<String> {
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index a8c216407f931..9d90400965040 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -12,6 +12,7 @@ use rustc_middle::{
 use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{sym, BytePos, Span};
+use rustc_target::abi::FieldIdx;
 
 use crate::diagnostics::BorrowedContentSource;
 use crate::MirBorrowckCtxt;
@@ -1275,7 +1276,7 @@ fn is_closure_or_generator(ty: Ty<'_>) -> bool {
 fn get_mut_span_in_struct_field<'tcx>(
     tcx: TyCtxt<'tcx>,
     ty: Ty<'tcx>,
-    field: mir::Field,
+    field: FieldIdx,
 ) -> Option<Span> {
     // Expect our local to be a reference to a struct of some kind.
     if let ty::Ref(_, ty, _) = ty.kind()
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index b7ce3afce7bb2..2f64ccee686a8 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -33,12 +33,13 @@ use rustc_middle::mir::{
     Place, PlaceElem, PlaceRef, VarDebugInfoContents,
 };
 use rustc_middle::mir::{AggregateKind, BasicBlock, BorrowCheckResult, BorrowKind};
-use rustc_middle::mir::{Field, ProjectionElem, Promoted, Rvalue, Statement, StatementKind};
 use rustc_middle::mir::{InlineAsmOperand, Terminator, TerminatorKind};
+use rustc_middle::mir::{ProjectionElem, Promoted, Rvalue, Statement, StatementKind};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, CapturedPlace, ParamEnv, RegionVid, TyCtxt};
 use rustc_session::lint::builtin::UNUSED_MUT;
 use rustc_span::{Span, Symbol};
+use rustc_target::abi::FieldIdx;
 
 use either::Either;
 use smallvec::SmallVec;
@@ -597,7 +598,7 @@ struct MirBorrowckCtxt<'cx, 'tcx> {
     used_mut: FxIndexSet<Local>,
     /// If the function we're checking is a closure, then we'll need to report back the list of
     /// mutable upvars that have been used. This field keeps track of them.
-    used_mut_upvars: SmallVec<[Field; 8]>,
+    used_mut_upvars: SmallVec<[FieldIdx; 8]>,
     /// Region inference context. This contains the results from region inference and lets us e.g.
     /// find out which CFG points are contained in each borrow region.
     regioncx: Rc<RegionInferenceContext<'tcx>>,
@@ -2277,7 +2278,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// then returns the index of the field being projected. Note that this closure will always
     /// be `self` in the current MIR, because that is the only time we directly access the fields
     /// of a closure type.
-    fn is_upvar_field_projection(&self, place_ref: PlaceRef<'tcx>) -> Option<Field> {
+    fn is_upvar_field_projection(&self, place_ref: PlaceRef<'tcx>) -> Option<FieldIdx> {
         path_utils::is_upvar_field_projection(self.infcx.tcx, &self.upvars, place_ref, self.body())
     }
 
diff --git a/compiler/rustc_borrowck/src/path_utils.rs b/compiler/rustc_borrowck/src/path_utils.rs
index f8a99a2699e6f..ea9f8683ca7bb 100644
--- a/compiler/rustc_borrowck/src/path_utils.rs
+++ b/compiler/rustc_borrowck/src/path_utils.rs
@@ -7,8 +7,9 @@ use crate::BorrowIndex;
 use crate::Upvar;
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_middle::mir::BorrowKind;
-use rustc_middle::mir::{BasicBlock, Body, Field, Location, Place, PlaceRef, ProjectionElem};
+use rustc_middle::mir::{BasicBlock, Body, Location, Place, PlaceRef, ProjectionElem};
 use rustc_middle::ty::TyCtxt;
+use rustc_target::abi::FieldIdx;
 
 /// Returns `true` if the borrow represented by `kind` is
 /// allowed to be split into separate Reservation and
@@ -148,7 +149,7 @@ pub(crate) fn is_upvar_field_projection<'tcx>(
     upvars: &[Upvar<'tcx>],
     place_ref: PlaceRef<'tcx>,
     body: &Body<'tcx>,
-) -> Option<Field> {
+) -> Option<FieldIdx> {
     let mut place_ref = place_ref;
     let mut by_ref = false;
 
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index 4b27d24098517..04da6d6beff68 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -36,7 +36,7 @@ use rustc_middle::ty::{
 };
 use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::{Span, DUMMY_SP};
-use rustc_target::abi::FIRST_VARIANT;
+use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
 use rustc_trait_selection::traits::query::type_op::custom::scrape_region_constraints;
 use rustc_trait_selection::traits::query::type_op::custom::CustomTypeOp;
 use rustc_trait_selection::traits::query::type_op::{TypeOp, TypeOpOutput};
@@ -786,7 +786,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
         &mut self,
         parent: &dyn fmt::Debug,
         base_ty: PlaceTy<'tcx>,
-        field: Field,
+        field: FieldIdx,
         location: Location,
     ) -> Result<Ty<'tcx>, FieldAccessError> {
         let tcx = self.tcx();
diff --git a/compiler/rustc_codegen_cranelift/src/abi/mod.rs b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
index 3bc64c44524ed..91c085d3d6986 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
@@ -327,7 +327,7 @@ pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_
             ArgKind::Spread(params) => {
                 for (i, param) in params.into_iter().enumerate() {
                     if let Some(param) = param {
-                        place.place_field(fx, mir::Field::new(i)).write_cvalue(fx, param);
+                        place.place_field(fx, FieldIdx::new(i)).write_cvalue(fx, param);
                     }
                 }
             }
@@ -460,7 +460,7 @@ pub(crate) fn codegen_terminator_call<'tcx>(
         args.push(self_arg);
         for i in 0..tupled_arguments.len() {
             args.push(CallArgument {
-                value: pack_arg.value.value_field(fx, mir::Field::new(i)),
+                value: pack_arg.value.value_field(fx, FieldIdx::new(i)),
                 is_owned: pack_arg.is_owned,
             });
         }
diff --git a/compiler/rustc_codegen_cranelift/src/base.rs b/compiler/rustc_codegen_cranelift/src/base.rs
index 1825fb8cb2288..615ef58ff5829 100644
--- a/compiler/rustc_codegen_cranelift/src/base.rs
+++ b/compiler/rustc_codegen_cranelift/src/base.rs
@@ -797,7 +797,7 @@ fn codegen_stmt<'tcx>(
                             let index = fx.bcx.ins().iconst(fx.pointer_type, field_index as i64);
                             variant_dest.place_index(fx, index)
                         } else {
-                            variant_dest.place_field(fx, mir::Field::new(field_index))
+                            variant_dest.place_field(fx, FieldIdx::new(field_index))
                         };
                         to.write_cvalue(fx, operand);
                     }
diff --git a/compiler/rustc_codegen_cranelift/src/discriminant.rs b/compiler/rustc_codegen_cranelift/src/discriminant.rs
index 3cbf313adf0df..f740945a03c31 100644
--- a/compiler/rustc_codegen_cranelift/src/discriminant.rs
+++ b/compiler/rustc_codegen_cranelift/src/discriminant.rs
@@ -26,7 +26,7 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
             tag_encoding: TagEncoding::Direct,
             variants: _,
         } => {
-            let ptr = place.place_field(fx, mir::Field::new(tag_field));
+            let ptr = place.place_field(fx, FieldIdx::new(tag_field));
             let to = layout.ty.discriminant_for_variant(fx.tcx, variant_index).unwrap().val;
             let to = if ptr.layout().abi.is_signed() {
                 ty::ScalarInt::try_from_int(
@@ -47,7 +47,7 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
             variants: _,
         } => {
             if variant_index != untagged_variant {
-                let niche = place.place_field(fx, mir::Field::new(tag_field));
+                let niche = place.place_field(fx, FieldIdx::new(tag_field));
                 let niche_type = fx.clif_type(niche.layout().ty).unwrap();
                 let niche_value = variant_index.as_u32() - niche_variants.start().as_u32();
                 let niche_value = (niche_value as u128).wrapping_add(niche_start);
@@ -107,7 +107,7 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
     let cast_to = fx.clif_type(dest_layout.ty).unwrap();
 
     // Read the tag/niche-encoded discriminant from memory.
-    let tag = value.value_field(fx, mir::Field::new(tag_field));
+    let tag = value.value_field(fx, FieldIdx::new(tag_field));
     let tag = tag.load_scalar(fx);
 
     // Decode the discriminant (specifically if it's niche-encoded).
diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/llvm_x86.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/llvm_x86.rs
index e5c4b244a1afd..0f32d1a25ffad 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/llvm_x86.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/llvm_x86.rs
@@ -179,8 +179,8 @@ fn llvm_add_sub<'tcx>(
 
     // c + carry -> c + first intermediate carry or borrow respectively
     let int0 = crate::num::codegen_checked_int_binop(fx, bin_op, a, b);
-    let c = int0.value_field(fx, mir::Field::new(0));
-    let cb0 = int0.value_field(fx, mir::Field::new(1)).load_scalar(fx);
+    let c = int0.value_field(fx, FieldIdx::new(0));
+    let cb0 = int0.value_field(fx, FieldIdx::new(1)).load_scalar(fx);
 
     // c + carry -> c + second intermediate carry or borrow respectively
     let cb_in_as_u64 = fx.bcx.ins().uextend(types::I64, cb_in);
diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
index 034b4e8072cc5..6f54a8d49c867 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
@@ -253,7 +253,7 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
             }
 
             ret.write_cvalue(fx, base);
-            let ret_lane = ret.place_field(fx, mir::Field::new(idx.try_into().unwrap()));
+            let ret_lane = ret.place_field(fx, FieldIdx::new(idx.try_into().unwrap()));
             ret_lane.write_cvalue(fx, val);
         }
 
diff --git a/compiler/rustc_codegen_cranelift/src/lib.rs b/compiler/rustc_codegen_cranelift/src/lib.rs
index 1bd03403f244b..8cc7f6c34b021 100644
--- a/compiler/rustc_codegen_cranelift/src/lib.rs
+++ b/compiler/rustc_codegen_cranelift/src/lib.rs
@@ -86,7 +86,7 @@ mod prelude {
         self, FloatTy, Instance, InstanceDef, IntTy, ParamEnv, Ty, TyCtxt, TypeAndMut,
         TypeFoldable, TypeVisitableExt, UintTy,
     };
-    pub(crate) use rustc_target::abi::{Abi, Scalar, Size, VariantIdx, FIRST_VARIANT};
+    pub(crate) use rustc_target::abi::{Abi, FieldIdx, Scalar, Size, VariantIdx, FIRST_VARIANT};
 
     pub(crate) use rustc_data_structures::fx::FxHashMap;
 
diff --git a/compiler/rustc_codegen_cranelift/src/unsize.rs b/compiler/rustc_codegen_cranelift/src/unsize.rs
index 93eefd92342d8..ff0e12410e703 100644
--- a/compiler/rustc_codegen_cranelift/src/unsize.rs
+++ b/compiler/rustc_codegen_cranelift/src/unsize.rs
@@ -147,8 +147,8 @@ pub(crate) fn coerce_unsized_into<'tcx>(
             assert_eq!(def_a, def_b);
 
             for i in 0..def_a.variant(FIRST_VARIANT).fields.len() {
-                let src_f = src.value_field(fx, mir::Field::new(i));
-                let dst_f = dst.place_field(fx, mir::Field::new(i));
+                let src_f = src.value_field(fx, FieldIdx::new(i));
+                let dst_f = dst.place_field(fx, FieldIdx::new(i));
 
                 if dst_f.layout().is_zst() {
                     continue;
diff --git a/compiler/rustc_codegen_cranelift/src/value_and_place.rs b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
index 58e0a498292d4..ffe3ccb0eca04 100644
--- a/compiler/rustc_codegen_cranelift/src/value_and_place.rs
+++ b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
@@ -10,7 +10,7 @@ fn codegen_field<'tcx>(
     base: Pointer,
     extra: Option<Value>,
     layout: TyAndLayout<'tcx>,
-    field: mir::Field,
+    field: FieldIdx,
 ) -> (Pointer, TyAndLayout<'tcx>) {
     let field_offset = layout.fields.offset(field.index());
     let field_layout = layout.field(&*fx, field.index());
@@ -210,7 +210,7 @@ impl<'tcx> CValue<'tcx> {
     pub(crate) fn value_field(
         self,
         fx: &mut FunctionCx<'_, '_, 'tcx>,
-        field: mir::Field,
+        field: FieldIdx,
     ) -> CValue<'tcx> {
         let layout = self.1;
         match self.0 {
@@ -687,7 +687,7 @@ impl<'tcx> CPlace<'tcx> {
     pub(crate) fn place_field(
         self,
         fx: &mut FunctionCx<'_, '_, 'tcx>,
-        field: mir::Field,
+        field: FieldIdx,
     ) -> CPlace<'tcx> {
         let layout = self.layout();
 
diff --git a/compiler/rustc_codegen_cranelift/src/vtable.rs b/compiler/rustc_codegen_cranelift/src/vtable.rs
index 94806e0d798ed..b309695c190f8 100644
--- a/compiler/rustc_codegen_cranelift/src/vtable.rs
+++ b/compiler/rustc_codegen_cranelift/src/vtable.rs
@@ -50,7 +50,7 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
         if let Abi::Scalar(_) = arg.layout().abi {
             'descend_newtypes: while !arg.layout().ty.is_unsafe_ptr() && !arg.layout().ty.is_ref() {
                 for i in 0..arg.layout().fields.count() {
-                    let field = arg.value_field(fx, mir::Field::new(i));
+                    let field = arg.value_field(fx, FieldIdx::new(i));
                     if !field.layout().is_zst() {
                         // we found the one non-zero-sized field that is allowed
                         // now find *its* non-zero-sized field, or stop if it's a
@@ -68,9 +68,9 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
             if ty.is_dyn_star() {
                 let inner_layout = fx.layout_of(arg.layout().ty.builtin_deref(true).unwrap().ty);
                 let dyn_star = CPlace::for_ptr(Pointer::new(arg.load_scalar(fx)), inner_layout);
-                let ptr = dyn_star.place_field(fx, mir::Field::new(0)).to_ptr();
+                let ptr = dyn_star.place_field(fx, FieldIdx::new(0)).to_ptr();
                 let vtable =
-                    dyn_star.place_field(fx, mir::Field::new(1)).to_cvalue(fx).load_scalar(fx);
+                    dyn_star.place_field(fx, FieldIdx::new(1)).to_cvalue(fx).load_scalar(fx);
                 break 'block (ptr, vtable);
             }
         }
diff --git a/compiler/rustc_codegen_llvm/messages.ftl b/compiler/rustc_codegen_llvm/messages.ftl
index e5df417370bb9..b6d7484bccefd 100644
--- a/compiler/rustc_codegen_llvm/messages.ftl
+++ b/compiler/rustc_codegen_llvm/messages.ftl
@@ -27,7 +27,8 @@ codegen_llvm_error_calling_dlltool =
     Error calling dlltool: {$error}
 
 codegen_llvm_dlltool_fail_import_library =
-    Dlltool could not create import library: {$stdout}\n{$stderr}
+    Dlltool could not create import library: {$stdout}
+    {$stderr}
 
 codegen_llvm_target_feature_disable_or_enable =
     the target features {$features} must all be either enabled or disabled together
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
index 54e850f25996b..3e4765fba57d5 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
@@ -6,7 +6,7 @@ use rustc_hir::def::CtorKind;
 use rustc_index::vec::IndexVec;
 use rustc_middle::{
     bug,
-    mir::{Field, GeneratorLayout, GeneratorSavedLocal},
+    mir::{GeneratorLayout, GeneratorSavedLocal},
     ty::{
         self,
         layout::{IntegerExt, LayoutOf, PrimitiveExt, TyAndLayout},
@@ -14,7 +14,9 @@ use rustc_middle::{
     },
 };
 use rustc_span::Symbol;
-use rustc_target::abi::{HasDataLayout, Integer, Primitive, TagEncoding, VariantIdx, Variants};
+use rustc_target::abi::{
+    FieldIdx, HasDataLayout, Integer, Primitive, TagEncoding, VariantIdx, Variants,
+};
 use std::borrow::Cow;
 
 use crate::{
@@ -353,7 +355,7 @@ pub fn build_generator_variant_struct_type_di_node<'ll, 'tcx>(
             let state_specific_fields: SmallVec<_> = (0..variant_layout.fields.count())
                 .map(|field_index| {
                     let generator_saved_local = generator_layout.variant_fields[variant_index]
-                        [Field::from_usize(field_index)];
+                        [FieldIdx::from_usize(field_index)];
                     let field_name_maybe = state_specific_upvar_names[generator_saved_local];
                     let field_name = field_name_maybe
                         .as_ref()
diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index d15774696a52b..ff25d1e38236d 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -8,7 +8,7 @@ use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
 use rustc_session::config::DebugInfo;
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{BytePos, Span};
-use rustc_target::abi::{Abi, Size, VariantIdx};
+use rustc_target::abi::{Abi, FieldIdx, Size, VariantIdx};
 
 use super::operand::{OperandRef, OperandValue};
 use super::place::PlaceRef;
@@ -79,7 +79,7 @@ impl<'tcx, S: Copy, L: Copy> DebugScope<S, L> {
 trait DebugInfoOffsetLocation<'tcx, Bx> {
     fn deref(&self, bx: &mut Bx) -> Self;
     fn layout(&self) -> TyAndLayout<'tcx>;
-    fn project_field(&self, bx: &mut Bx, field: mir::Field) -> Self;
+    fn project_field(&self, bx: &mut Bx, field: FieldIdx) -> Self;
     fn downcast(&self, bx: &mut Bx, variant: VariantIdx) -> Self;
 }
 
@@ -94,7 +94,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> DebugInfoOffsetLocation<'tcx, Bx>
         self.layout
     }
 
-    fn project_field(&self, bx: &mut Bx, field: mir::Field) -> Self {
+    fn project_field(&self, bx: &mut Bx, field: FieldIdx) -> Self {
         PlaceRef::project_field(*self, bx, field.index())
     }
 
@@ -116,7 +116,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> DebugInfoOffsetLocation<'tcx, Bx>
         *self
     }
 
-    fn project_field(&self, bx: &mut Bx, field: mir::Field) -> Self {
+    fn project_field(&self, bx: &mut Bx, field: FieldIdx) -> Self {
         self.field(bx.cx(), field.index())
     }
 
diff --git a/compiler/rustc_const_eval/messages.ftl b/compiler/rustc_const_eval/messages.ftl
index 33bb116d6fa23..f6751df443f7a 100644
--- a/compiler/rustc_const_eval/messages.ftl
+++ b/compiler/rustc_const_eval/messages.ftl
@@ -39,17 +39,25 @@ const_eval_unstable_const_fn = `{$def_path}` is not yet stable as a const fn
 const_eval_unallowed_mutable_refs =
     mutable references are not allowed in the final value of {$kind}s
     .teach_note =
-        References in statics and constants may only refer to immutable values.\n\n
+        References in statics and constants may only refer to immutable values.
+
+
         Statics are shared everywhere, and if they refer to mutable data one might violate memory
-        safety since holding multiple mutable references to shared data is not allowed.\n\n
+        safety since holding multiple mutable references to shared data is not allowed.
+
+
         If you really want global mutable state, try using static mut or a global UnsafeCell.
 
 const_eval_unallowed_mutable_refs_raw =
     raw mutable references are not allowed in the final value of {$kind}s
     .teach_note =
-        References in statics and constants may only refer to immutable values.\n\n
+        References in statics and constants may only refer to immutable values.
+
+
         Statics are shared everywhere, and if they refer to mutable data one might violate memory
-        safety since holding multiple mutable references to shared data is not allowed.\n\n
+        safety since holding multiple mutable references to shared data is not allowed.
+
+
         If you really want global mutable state, try using static mut or a global UnsafeCell.
 
 const_eval_non_const_fmt_macro_call =
diff --git a/compiler/rustc_incremental/messages.ftl b/compiler/rustc_incremental/messages.ftl
index 4852ee0d9595c..b760620e3d48b 100644
--- a/compiler/rustc_incremental/messages.ftl
+++ b/compiler/rustc_incremental/messages.ftl
@@ -24,7 +24,7 @@ incremental_field_associated_value_expected = associated value expected for `{$n
 incremental_no_field = no field `{$name}`
 
 incremental_assertion_auto =
-    `except` specified DepNodes that can not be affected for \"{$name}\": \"{$e}\"
+    `except` specified DepNodes that can not be affected for "{$name}": "{$e}"
 
 incremental_undefined_clean_dirty_assertions_item =
     clean/dirty auto-assertions not yet defined for Node::Item.node={$kind}
diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl
index 68e62c9789aed..d9c8142226d2b 100644
--- a/compiler/rustc_lint/messages.ftl
+++ b/compiler/rustc_lint/messages.ftl
@@ -91,7 +91,7 @@ lint_ty_qualified = usage of qualified `ty::{$ty}`
 lint_lintpass_by_hand = implementing `LintPass` by hand
     .help = try using `declare_lint_pass!` or `impl_lint_pass!` instead
 
-lint_non_existant_doc_keyword = found non-existing keyword `{$keyword}` used in `#[doc(keyword = \"...\")]`
+lint_non_existant_doc_keyword = found non-existing keyword `{$keyword}` used in `#[doc(keyword = "...")]`
     .help = only existing keywords are allowed in core/std
 
 lint_diag_out_of_impl =
@@ -197,7 +197,9 @@ lint_drop_glue =
     types that do not implement `Drop` can still have drop glue, consider instead using `{$needs_drop}` to detect whether a type is trivially dropped
 
 lint_range_endpoint_out_of_range = range endpoint is out of range for `{$ty}`
-    .suggestion = use an inclusive range instead
+
+lint_range_use_inclusive_range = use an inclusive range instead
+
 
 lint_overflowing_bin_hex = literal out of range for `{$ty}`
     .negative_note = the literal `{$lit}` (decimal `{$dec}`) does not fit into the type `{$ty}`
diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
index 308c02929ca42..8ec4c2b3d463a 100644
--- a/compiler/rustc_lint/src/lints.rs
+++ b/compiler/rustc_lint/src/lints.rs
@@ -1210,11 +1210,33 @@ impl<'a> DecorateLint<'a, ()> for DropGlue<'_> {
 #[diag(lint_range_endpoint_out_of_range)]
 pub struct RangeEndpointOutOfRange<'a> {
     pub ty: &'a str,
-    #[suggestion(code = "{start}..={literal}{suffix}", applicability = "machine-applicable")]
-    pub suggestion: Span,
-    pub start: String,
-    pub literal: u128,
-    pub suffix: &'a str,
+    #[subdiagnostic]
+    pub sub: UseInclusiveRange<'a>,
+}
+
+#[derive(Subdiagnostic)]
+pub enum UseInclusiveRange<'a> {
+    #[suggestion(
+        lint_range_use_inclusive_range,
+        code = "{start}..={literal}{suffix}",
+        applicability = "machine-applicable"
+    )]
+    WithoutParen {
+        #[primary_span]
+        sugg: Span,
+        start: String,
+        literal: u128,
+        suffix: &'a str,
+    },
+    #[multipart_suggestion(lint_range_use_inclusive_range, applicability = "machine-applicable")]
+    WithParen {
+        #[suggestion_part(code = "=")]
+        eq_sugg: Span,
+        #[suggestion_part(code = "{literal}{suffix}")]
+        lit_sugg: Span,
+        literal: u128,
+        suffix: &'a str,
+    },
 }
 
 #[derive(LintDiagnostic)]
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs
index 7ca50f5a2db70..f6bca7045c846 100644
--- a/compiler/rustc_lint/src/types.rs
+++ b/compiler/rustc_lint/src/types.rs
@@ -4,7 +4,8 @@ use crate::{
         AtomicOrderingFence, AtomicOrderingLoad, AtomicOrderingStore, ImproperCTypes,
         InvalidAtomicOrderingDiag, OnlyCastu8ToChar, OverflowingBinHex, OverflowingBinHexSign,
         OverflowingBinHexSub, OverflowingInt, OverflowingIntHelp, OverflowingLiteral,
-        OverflowingUInt, RangeEndpointOutOfRange, UnusedComparisons, VariantSizeDifferencesDiag,
+        OverflowingUInt, RangeEndpointOutOfRange, UnusedComparisons, UseInclusiveRange,
+        VariantSizeDifferencesDiag,
     },
 };
 use crate::{LateContext, LateLintPass, LintContext};
@@ -136,6 +137,14 @@ fn lint_overflowing_range_endpoint<'tcx>(
     expr: &'tcx hir::Expr<'tcx>,
     ty: &str,
 ) -> bool {
+    // Look past casts to support cases like `0..256 as u8`
+    let (expr, lit_span) = if let Node::Expr(par_expr) = cx.tcx.hir().get(cx.tcx.hir().parent_id(expr.hir_id))
+      && let ExprKind::Cast(_, _) = par_expr.kind {
+        (par_expr, expr.span)
+    } else {
+        (expr, expr.span)
+    };
+
     // We only want to handle exclusive (`..`) ranges,
     // which are represented as `ExprKind::Struct`.
     let par_id = cx.tcx.hir().parent_id(expr.hir_id);
@@ -155,7 +164,6 @@ fn lint_overflowing_range_endpoint<'tcx>(
     if !(eps[1].expr.hir_id == expr.hir_id && lit_val - 1 == max) {
         return false;
     };
-    let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) else { return false };
 
     use rustc_ast::{LitIntType, LitKind};
     let suffix = match lit.node {
@@ -164,16 +172,28 @@ fn lint_overflowing_range_endpoint<'tcx>(
         LitKind::Int(_, LitIntType::Unsuffixed) => "",
         _ => bug!(),
     };
-    cx.emit_spanned_lint(
-        OVERFLOWING_LITERALS,
-        struct_expr.span,
-        RangeEndpointOutOfRange {
-            ty,
-            suggestion: struct_expr.span,
+
+    let sub_sugg = if expr.span.lo() == lit_span.lo() {
+        let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) else { return false };
+        UseInclusiveRange::WithoutParen {
+            sugg: struct_expr.span.shrink_to_lo().to(lit_span.shrink_to_hi()),
             start,
             literal: lit_val - 1,
             suffix,
-        },
+        }
+    } else {
+        UseInclusiveRange::WithParen {
+            eq_sugg: expr.span.shrink_to_lo(),
+            lit_sugg: lit_span,
+            literal: lit_val - 1,
+            suffix,
+        }
+    };
+
+    cx.emit_spanned_lint(
+        OVERFLOWING_LITERALS,
+        struct_expr.span,
+        RangeEndpointOutOfRange { ty, sub: sub_sugg },
     );
 
     // We've just emitted a lint, special cased for `(...)..MAX+1` ranges,
diff --git a/compiler/rustc_macros/src/diagnostics/fluent.rs b/compiler/rustc_macros/src/diagnostics/fluent.rs
index 38c0f4895db06..3b2f5cfdc7316 100644
--- a/compiler/rustc_macros/src/diagnostics/fluent.rs
+++ b/compiler/rustc_macros/src/diagnostics/fluent.rs
@@ -111,6 +111,18 @@ pub(crate) fn fluent_messages(input: proc_macro::TokenStream) -> proc_macro::Tok
             .emit();
         return failed(&crate_name);
     }
+    let mut bad = false;
+    for esc in ["\\n", "\\\"", "\\'"] {
+        for _ in resource_contents.matches(esc) {
+            bad = true;
+            Diagnostic::spanned(resource_span, Level::Error, format!("invalid escape `{esc}` in Fluent resource"))
+                .note("Fluent does not interpret these escape sequences (<https://projectfluent.org/fluent/guide/special.html>)")
+                .emit();
+        }
+    }
+    if bad {
+        return failed(&crate_name);
+    }
 
     let resource = match FluentResource::try_new(resource_contents) {
         Ok(resource) => resource,
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 9c575f6eb9fd0..37356b53c0271 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -21,7 +21,7 @@ use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
 use rustc_hir::{self, GeneratorKind, ImplicitSelfKind};
 use rustc_hir::{self as hir, HirId};
 use rustc_session::Session;
-use rustc_target::abi::{Size, VariantIdx};
+use rustc_target::abi::{FieldIdx, Size, VariantIdx};
 
 use polonius_engine::Atom;
 pub use rustc_ast::Mutability;
@@ -1512,7 +1512,7 @@ impl<V, T> ProjectionElem<V, T> {
     }
 
     /// Returns `true` if this is a `Field` projection with the given index.
-    pub fn is_field_to(&self, f: Field) -> bool {
+    pub fn is_field_to(&self, f: FieldIdx) -> bool {
         matches!(*self, Self::Field(x, _) if x == f)
     }
 }
@@ -1521,22 +1521,6 @@ impl<V, T> ProjectionElem<V, T> {
 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
 pub type ProjectionKind = ProjectionElem<(), ()>;
 
-rustc_index::newtype_index! {
-    /// A [newtype'd][wrapper] index type in the MIR [control-flow graph][CFG]
-    ///
-    /// A field (e.g., `f` in `_1.f`) is one variant of [`ProjectionElem`]. Conceptually,
-    /// rustc can identify that a field projection refers to either two different regions of memory
-    /// or the same one between the base and the 'projection element'.
-    /// Read more about projections in the [rustc-dev-guide][mir-datatypes]
-    ///
-    /// [wrapper]: https://rustc-dev-guide.rust-lang.org/appendix/glossary.html#newtype
-    /// [CFG]: https://rustc-dev-guide.rust-lang.org/appendix/background.html#cfg
-    /// [mir-datatypes]: https://rustc-dev-guide.rust-lang.org/mir/index.html#mir-data-types
-    #[derive(HashStable)]
-    #[debug_format = "field[{}]"]
-    pub struct Field {}
-}
-
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub struct PlaceRef<'tcx> {
     pub local: Local,
@@ -2685,12 +2669,17 @@ impl<'tcx> UserTypeProjections {
         self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
     }
 
-    pub fn leaf(self, field: Field) -> Self {
+    pub fn leaf(self, field: FieldIdx) -> Self {
         self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
     }
 
-    pub fn variant(self, adt_def: AdtDef<'tcx>, variant_index: VariantIdx, field: Field) -> Self {
-        self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
+    pub fn variant(
+        self,
+        adt_def: AdtDef<'tcx>,
+        variant_index: VariantIdx,
+        field_index: FieldIdx,
+    ) -> Self {
+        self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field_index))
     }
 }
 
@@ -2733,7 +2722,7 @@ impl UserTypeProjection {
         self
     }
 
-    pub(crate) fn leaf(mut self, field: Field) -> Self {
+    pub(crate) fn leaf(mut self, field: FieldIdx) -> Self {
         self.projs.push(ProjectionElem::Field(field, ()));
         self
     }
@@ -2742,13 +2731,13 @@ impl UserTypeProjection {
         mut self,
         adt_def: AdtDef<'_>,
         variant_index: VariantIdx,
-        field: Field,
+        field_index: FieldIdx,
     ) -> Self {
         self.projs.push(ProjectionElem::Downcast(
             Some(adt_def.variant(variant_index).name),
             variant_index,
         ));
-        self.projs.push(ProjectionElem::Field(field, ()));
+        self.projs.push(ProjectionElem::Field(field_index, ()));
         self
     }
 }
diff --git a/compiler/rustc_middle/src/mir/query.rs b/compiler/rustc_middle/src/mir/query.rs
index 786c2e9cd943e..68561cf6dd775 100644
--- a/compiler/rustc_middle/src/mir/query.rs
+++ b/compiler/rustc_middle/src/mir/query.rs
@@ -10,12 +10,12 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_index::bit_set::BitMatrix;
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_span::Span;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use smallvec::SmallVec;
 use std::cell::Cell;
 use std::fmt::{self, Debug};
 
-use super::{Field, SourceInfo};
+use super::SourceInfo;
 
 #[derive(Copy, Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
 pub enum UnsafetyViolationKind {
@@ -152,7 +152,7 @@ pub struct GeneratorLayout<'tcx> {
 
     /// Which of the above fields are in each variant. Note that one field may
     /// be stored in multiple variants.
-    pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
+    pub variant_fields: IndexVec<VariantIdx, IndexVec<FieldIdx, GeneratorSavedLocal>>,
 
     /// The source that led to each variant being created (usually, a yield or
     /// await).
@@ -229,7 +229,7 @@ pub struct BorrowCheckResult<'tcx> {
     /// unerased regions.
     pub concrete_opaque_types: FxIndexMap<LocalDefId, OpaqueHiddenType<'tcx>>,
     pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
-    pub used_mut_upvars: SmallVec<[Field; 8]>,
+    pub used_mut_upvars: SmallVec<[FieldIdx; 8]>,
     pub tainted_by_errors: Option<ErrorGuaranteed>,
 }
 
@@ -353,7 +353,7 @@ pub enum ConstraintCategory<'tcx> {
     /// like `Foo { field: my_val }`)
     Usage,
     OpaqueType,
-    ClosureUpvar(Field),
+    ClosureUpvar(FieldIdx),
 
     /// A constraint from a user-written predicate
     /// with the provided span, written on the item
@@ -375,7 +375,7 @@ pub enum ConstraintCategory<'tcx> {
 #[derive(TyEncodable, TyDecodable, HashStable, TypeVisitable, TypeFoldable)]
 pub enum ReturnConstraint {
     Normal,
-    ClosureUpvar(Field),
+    ClosureUpvar(FieldIdx),
 }
 
 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index bbd913d071d48..8fb693055fa8a 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -3,7 +3,7 @@
 //! This is in a dedicated file so that changes to this file can be reviewed more carefully.
 //! The intention is that this file only contains datatype declarations, no code.
 
-use super::{BasicBlock, Constant, Field, Local, SwitchTargets, UserTypeProjection};
+use super::{BasicBlock, Constant, Local, SwitchTargets, UserTypeProjection};
 
 use crate::mir::coverage::{CodeRegion, CoverageKind};
 use crate::traits::Reveal;
@@ -16,7 +16,7 @@ use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_hir::def_id::DefId;
 use rustc_hir::{self as hir};
 use rustc_hir::{self, GeneratorKind};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 
 use rustc_ast::Mutability;
 use rustc_span::def_id::LocalDefId;
@@ -888,7 +888,15 @@ pub struct Place<'tcx> {
 #[derive(TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
 pub enum ProjectionElem<V, T> {
     Deref,
-    Field(Field, T),
+
+    /// A field (e.g., `f` in `_1.f`) is one variant of [`ProjectionElem`]. Conceptually,
+    /// rustc can identify that a field projection refers to either two different regions of memory
+    /// or the same one between the base and the 'projection element'.
+    /// Read more about projections in the [rustc-dev-guide][mir-datatypes]
+    ///
+    /// [mir-datatypes]: https://rustc-dev-guide.rust-lang.org/mir/index.html#mir-data-types
+    Field(FieldIdx, T),
+
     /// Index into a slice/array.
     ///
     /// Note that this does not also dereference, and so it does not exactly correspond to slice
diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs
index ee439df8b6b7c..4a28aabf8a358 100644
--- a/compiler/rustc_middle/src/mir/tcx.rs
+++ b/compiler/rustc_middle/src/mir/tcx.rs
@@ -6,7 +6,7 @@
 use crate::mir::*;
 use crate::ty::{self, Ty, TyCtxt};
 use rustc_hir as hir;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 
 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
 pub struct PlaceTy<'tcx> {
@@ -33,7 +33,7 @@ impl<'tcx> PlaceTy<'tcx> {
     ///
     /// Note that the resulting type has not been normalized.
     #[instrument(level = "debug", skip(tcx), ret)]
-    pub fn field_ty(self, tcx: TyCtxt<'tcx>, f: Field) -> Ty<'tcx> {
+    pub fn field_ty(self, tcx: TyCtxt<'tcx>, f: FieldIdx) -> Ty<'tcx> {
         match self.ty.kind() {
             ty::Adt(adt_def, substs) => {
                 let variant_def = match self.variant_index {
@@ -61,14 +61,14 @@ impl<'tcx> PlaceTy<'tcx> {
     /// `place_ty.projection_ty_core(tcx, elem, |...| { ... })`
     /// projects `place_ty` onto `elem`, returning the appropriate
     /// `Ty` or downcast variant corresponding to that projection.
-    /// The `handle_field` callback must map a `Field` to its `Ty`,
+    /// The `handle_field` callback must map a `FieldIdx` to its `Ty`,
     /// (which should be trivial when `T` = `Ty`).
     pub fn projection_ty_core<V, T>(
         self,
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         elem: &ProjectionElem<V, T>,
-        mut handle_field: impl FnMut(&Self, Field, T) -> Ty<'tcx>,
+        mut handle_field: impl FnMut(&Self, FieldIdx, T) -> Ty<'tcx>,
         mut handle_opaque_cast: impl FnMut(&Self, T) -> Ty<'tcx>,
     ) -> PlaceTy<'tcx>
     where
diff --git a/compiler/rustc_middle/src/query/keys.rs b/compiler/rustc_middle/src/query/keys.rs
index ca65fbc2fd470..4a096a2c0e840 100644
--- a/compiler/rustc_middle/src/query/keys.rs
+++ b/compiler/rustc_middle/src/query/keys.rs
@@ -12,6 +12,7 @@ use rustc_hir::hir_id::{HirId, OwnerId};
 use rustc_query_system::query::{DefaultCacheSelector, SingleCacheSelector, VecCacheSelector};
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
+use rustc_target::abi::FieldIdx;
 
 /// Placeholder for `CrateNum`'s "local" counterpart
 #[derive(Copy, Clone, Debug)]
@@ -332,7 +333,7 @@ impl<'tcx> Key for (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>) {
     }
 }
 
-impl<'tcx> Key for (ty::Const<'tcx>, mir::Field) {
+impl<'tcx> Key for (ty::Const<'tcx>, FieldIdx) {
     type CacheSelector = DefaultCacheSelector<Self>;
 
     fn default_span(&self, _: TyCtxt<'_>) -> Span {
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index 3b11fab8cdf57..29e3055a4b860 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -17,14 +17,14 @@ use rustc_index::newtype_index;
 use rustc_index::vec::IndexVec;
 use rustc_middle::middle::region;
 use rustc_middle::mir::interpret::AllocId;
-use rustc_middle::mir::{self, BinOp, BorrowKind, FakeReadCause, Field, Mutability, UnOp};
+use rustc_middle::mir::{self, BinOp, BorrowKind, FakeReadCause, Mutability, UnOp};
 use rustc_middle::ty::adjustment::PointerCast;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, AdtDef, FnSig, Ty, UpvarSubsts};
 use rustc_middle::ty::{CanonicalUserType, CanonicalUserTypeAnnotation};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{sym, Span, Symbol, DUMMY_SP};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_target::asm::InlineAsmRegOrRegClass;
 use std::fmt;
 use std::ops::Index;
@@ -366,7 +366,7 @@ pub enum ExprKind<'tcx> {
         /// Variant containing the field.
         variant_index: VariantIdx,
         /// This can be a named (`.foo`) or unnamed (`.0`) field.
-        name: Field,
+        name: FieldIdx,
     },
     /// A *non-overloaded* indexing operation.
     Index {
@@ -491,7 +491,7 @@ pub enum ExprKind<'tcx> {
 /// This is used in struct constructors.
 #[derive(Clone, Debug, HashStable)]
 pub struct FieldExpr {
-    pub name: Field,
+    pub name: FieldIdx,
     pub expr: ExprId,
 }
 
@@ -570,7 +570,7 @@ pub enum BindingMode {
 
 #[derive(Clone, Debug, HashStable)]
 pub struct FieldPat<'tcx> {
-    pub field: Field,
+    pub field: FieldIdx,
     pub pattern: Box<Pat<'tcx>>,
 }
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index a1c1acc4a2541..8d0aa622244cd 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -12,9 +12,7 @@ use crate::middle::codegen_fn_attrs::CodegenFnAttrs;
 use crate::middle::resolve_bound_vars;
 use crate::middle::stability;
 use crate::mir::interpret::{self, Allocation, ConstAllocation};
-use crate::mir::{
-    Body, BorrowCheckResult, Field, Local, Place, PlaceElem, ProjectionKind, Promoted,
-};
+use crate::mir::{Body, BorrowCheckResult, Local, Place, PlaceElem, ProjectionKind, Promoted};
 use crate::query::LocalCrate;
 use crate::thir::Thir;
 use crate::traits;
@@ -65,7 +63,7 @@ use rustc_span::def_id::{DefPathHash, StableCrateId};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-use rustc_target::abi::{Layout, LayoutS, TargetDataLayout, VariantIdx};
+use rustc_target::abi::{FieldIdx, Layout, LayoutS, TargetDataLayout, VariantIdx};
 use rustc_target::spec::abi;
 use rustc_type_ir::sty::TyKind::*;
 use rustc_type_ir::WithCachedTypeInfo;
@@ -2125,7 +2123,7 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    pub fn mk_place_field(self, place: Place<'tcx>, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
+    pub fn mk_place_field(self, place: Place<'tcx>, f: FieldIdx, ty: Ty<'tcx>) -> Place<'tcx> {
         self.mk_place_elem(place, PlaceElem::Field(f, ty))
     }
 
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index c6bb814679586..d4f058440b954 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -4,7 +4,7 @@
 //! to help with the tedium.
 
 use crate::mir::interpret;
-use crate::mir::{Field, ProjectionKind};
+use crate::mir::ProjectionKind;
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{with_no_trimmed_paths, FmtPrinter, Printer};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
@@ -217,6 +217,7 @@ CloneLiftImpls! {
 // implementation and traversal implementations (the latter only for
 // TyCtxt<'_> interners).
 TrivialTypeTraversalAndLiftImpls! {
+    ::rustc_target::abi::FieldIdx,
     ::rustc_target::abi::VariantIdx,
     crate::middle::region::Scope,
     crate::ty::FloatTy,
@@ -268,7 +269,6 @@ TrivialTypeTraversalAndLiftImpls! {
     ::rustc_span::Span,
     ::rustc_span::symbol::Ident,
     ::rustc_errors::ErrorGuaranteed,
-    Field,
     interpret::Scalar,
     rustc_target::abi::Size,
     ty::BoundVar,
diff --git a/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
index bf58b3090fb8e..77a5017b3630f 100644
--- a/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
+++ b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
@@ -3,7 +3,7 @@ use rustc_middle::mir::tcx::PlaceTy;
 use rustc_middle::ty::cast::mir_cast_kind;
 use rustc_middle::{mir::*, thir::*, ty};
 use rustc_span::Span;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 
 use crate::build::custom::ParseError;
 use crate::build::expr::as_constant::as_constant_inner;
@@ -223,7 +223,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
         let (parent, proj) = parse_by_kind!(self, expr_id, expr, "place",
             @call("mir_field", args) => {
                 let (parent, ty) = self.parse_place_inner(args[0])?;
-                let field = Field::from_u32(self.parse_integer_literal(args[1])? as u32);
+                let field = FieldIdx::from_u32(self.parse_integer_literal(args[1])? as u32);
                 let field_ty = ty.field_ty(self.tcx, field);
                 let proj = PlaceElem::Field(field, field_ty);
                 let place = parent.project_deeper(&[proj], self.tcx);
diff --git a/compiler/rustc_mir_build/src/build/expr/as_place.rs b/compiler/rustc_mir_build/src/build/expr/as_place.rs
index e112bf9829b68..0fc99e57d1229 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_place.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_place.rs
@@ -13,7 +13,7 @@ use rustc_middle::thir::*;
 use rustc_middle::ty::AdtDef;
 use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, Ty, Variance};
 use rustc_span::Span;
-use rustc_target::abi::{VariantIdx, FIRST_VARIANT};
+use rustc_target::abi::{FieldIdx, VariantIdx, FIRST_VARIANT};
 
 use std::assert_matches::assert_matches;
 use std::iter;
@@ -293,7 +293,7 @@ impl<'tcx> PlaceBuilder<'tcx> {
         &self.projection
     }
 
-    pub(crate) fn field(self, f: Field, ty: Ty<'tcx>) -> Self {
+    pub(crate) fn field(self, f: FieldIdx, ty: Ty<'tcx>) -> Self {
         self.project(PlaceElem::Field(f, ty))
     }
 
diff --git a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
index 7fff801b1692d..d1878bf77ef1e 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
@@ -17,6 +17,7 @@ use rustc_middle::thir::*;
 use rustc_middle::ty::cast::{mir_cast_kind, CastTy};
 use rustc_middle::ty::{self, Ty, UpvarSubsts};
 use rustc_span::Span;
+use rustc_target::abi::FieldIdx;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// Returns an rvalue suitable for use until the end of the current
@@ -553,8 +554,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     result_value,
                     Rvalue::CheckedBinaryOp(op, Box::new((lhs.to_copy(), rhs.to_copy()))),
                 );
-                let val_fld = Field::new(0);
-                let of_fld = Field::new(1);
+                let val_fld = FieldIdx::new(0);
+                let of_fld = FieldIdx::new(1);
 
                 let tcx = self.tcx;
                 let val = tcx.mk_place_field(result_value, val_fld, ty);
diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs
index ebe8ea25ad3af..b8260c719c89a 100644
--- a/compiler/rustc_mir_build/src/build/expr/into.rs
+++ b/compiler/rustc_mir_build/src/build/expr/into.rs
@@ -10,6 +10,7 @@ use rustc_index::vec::Idx;
 use rustc_middle::mir::*;
 use rustc_middle::thir::*;
 use rustc_middle::ty::CanonicalUserTypeAnnotation;
+use rustc_target::abi::FieldIdx;
 use std::iter;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
@@ -344,7 +345,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     .collect();
 
                 let field_names: Vec<_> =
-                    (0..adt_def.variant(variant_index).fields.len()).map(Field::new).collect();
+                    (0..adt_def.variant(variant_index).fields.len()).map(FieldIdx::new).collect();
 
                 let fields: Vec<_> = if let Some(FruInfo { base, field_types }) = base {
                     let place_builder =
diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs
index 1923e10ddb586..e87e38fd04caf 100644
--- a/compiler/rustc_mir_build/src/build/mod.rs
+++ b/compiler/rustc_mir_build/src/build/mod.rs
@@ -25,6 +25,7 @@ use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 use rustc_span::Symbol;
+use rustc_target::abi::FieldIdx;
 use rustc_target::spec::abi::Abi;
 
 use super::lints;
@@ -793,7 +794,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let mutability = captured_place.mutability;
 
                 let mut projs = closure_env_projs.clone();
-                projs.push(ProjectionElem::Field(Field::new(i), ty));
+                projs.push(ProjectionElem::Field(FieldIdx::new(i), ty));
                 match capture {
                     ty::UpvarCapture::ByValue => {}
                     ty::UpvarCapture::ByRef(..) => {
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index 04e9273fc46c9..2a0b5d0473313 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -10,7 +10,7 @@ use rustc_middle::hir::place::Place as HirPlace;
 use rustc_middle::hir::place::PlaceBase as HirPlaceBase;
 use rustc_middle::hir::place::ProjectionKind as HirProjectionKind;
 use rustc_middle::middle::region;
-use rustc_middle::mir::{self, BinOp, BorrowKind, Field, UnOp};
+use rustc_middle::mir::{self, BinOp, BorrowKind, UnOp};
 use rustc_middle::thir::*;
 use rustc_middle::ty::adjustment::{
     Adjust, Adjustment, AutoBorrow, AutoBorrowMutability, PointerCast,
@@ -20,7 +20,7 @@ use rustc_middle::ty::{
     self, AdtKind, InlineConstSubsts, InlineConstSubstsParts, ScalarInt, Ty, UpvarSubsts, UserType,
 };
 use rustc_span::{sym, Span};
-use rustc_target::abi::FIRST_VARIANT;
+use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
 
 impl<'tcx> Cx<'tcx> {
     pub(crate) fn mirror_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) -> ExprId {
@@ -379,7 +379,7 @@ impl<'tcx> Cx<'tcx> {
                             .iter()
                             .enumerate()
                             .map(|(idx, e)| FieldExpr {
-                                name: Field::new(idx),
+                                name: FieldIdx::new(idx),
                                 expr: self.mirror_expr(e),
                             })
                             .collect();
@@ -733,7 +733,7 @@ impl<'tcx> Cx<'tcx> {
             hir::ExprKind::Field(ref source, ..) => ExprKind::Field {
                 lhs: self.mirror_expr(source),
                 variant_index: FIRST_VARIANT,
-                name: Field::new(self.typeck_results.field_index(expr.hir_id)),
+                name: FieldIdx::new(self.typeck_results.field_index(expr.hir_id)),
             },
             hir::ExprKind::Cast(ref source, ref cast_ty) => {
                 // Check for a user-given type annotation on this `cast`
@@ -1053,7 +1053,7 @@ impl<'tcx> Cx<'tcx> {
                 HirProjectionKind::Field(field, variant_index) => ExprKind::Field {
                     lhs: self.thir.exprs.push(captured_place_expr),
                     variant_index,
-                    name: Field::new(field as usize),
+                    name: FieldIdx::new(field as usize),
                 },
                 HirProjectionKind::Index | HirProjectionKind::Subslice => {
                     // We don't capture these projections, so we can ignore them here
@@ -1107,7 +1107,7 @@ impl<'tcx> Cx<'tcx> {
         fields
             .iter()
             .map(|field| FieldExpr {
-                name: Field::new(self.typeck_results.field_index(field.hir_id)),
+                name: FieldIdx::new(self.typeck_results.field_index(field.hir_id)),
                 expr: self.mirror_expr(field.expr),
             })
             .collect()
diff --git a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
index 274c2f06137a3..2dbef740d1a6e 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
@@ -2,11 +2,12 @@ use rustc_hir as hir;
 use rustc_index::vec::Idx;
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::Obligation;
-use rustc_middle::mir::{self, Field};
+use rustc_middle::mir;
 use rustc_middle::thir::{FieldPat, Pat, PatKind};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_session::lint;
 use rustc_span::Span;
+use rustc_target::abi::FieldIdx;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{self, ObligationCause};
 
@@ -218,7 +219,7 @@ impl<'tcx> ConstToPat<'tcx> {
     ) -> Result<Vec<FieldPat<'tcx>>, FallbackToConstRef> {
         vals.enumerate()
             .map(|(idx, val)| {
-                let field = Field::new(idx);
+                let field = FieldIdx::new(idx);
                 Ok(FieldPat { field, pattern: self.recur(val, false)? })
             })
             .collect()
diff --git a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
index 8a7b1fce51db4..e619e095496bc 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
@@ -53,14 +53,14 @@ use smallvec::{smallvec, SmallVec};
 use rustc_data_structures::captures::Captures;
 use rustc_hir::{HirId, RangeEnd};
 use rustc_index::vec::Idx;
-use rustc_middle::mir::{self, Field};
+use rustc_middle::mir;
 use rustc_middle::thir::{FieldPat, Pat, PatKind, PatRange};
 use rustc_middle::ty::layout::IntegerExt;
 use rustc_middle::ty::{self, Ty, TyCtxt, VariantDef};
 use rustc_middle::{middle::stability::EvalResult, mir::interpret::ConstValue};
 use rustc_session::lint;
 use rustc_span::{Span, DUMMY_SP};
-use rustc_target::abi::{Integer, Size, VariantIdx, FIRST_VARIANT};
+use rustc_target::abi::{FieldIdx, Integer, Size, VariantIdx, FIRST_VARIANT};
 
 use self::Constructor::*;
 use self::SliceKind::*;
@@ -1126,7 +1126,7 @@ impl<'tcx> SplitWildcard<'tcx> {
 /// Note that the number of fields of a constructor may not match the fields declared in the
 /// original struct/variant. This happens if a private or `non_exhaustive` field is uninhabited,
 /// because the code mustn't observe that it is uninhabited. In that case that field is not
-/// included in `fields`. For that reason, when you have a `mir::Field` you must use
+/// included in `fields`. For that reason, when you have a `FieldIdx` you must use
 /// `index_with_declared_idx`.
 #[derive(Debug, Clone, Copy)]
 pub(super) struct Fields<'p, 'tcx> {
@@ -1165,7 +1165,7 @@ impl<'p, 'tcx> Fields<'p, 'tcx> {
         cx: &'a MatchCheckCtxt<'p, 'tcx>,
         ty: Ty<'tcx>,
         variant: &'a VariantDef,
-    ) -> impl Iterator<Item = (Field, Ty<'tcx>)> + Captures<'a> + Captures<'p> {
+    ) -> impl Iterator<Item = (FieldIdx, Ty<'tcx>)> + Captures<'a> + Captures<'p> {
         let ty::Adt(adt, substs) = ty.kind() else { bug!() };
         // Whether we must not match the fields of this variant exhaustively.
         let is_non_exhaustive = variant.is_field_list_non_exhaustive() && !adt.did().is_local();
@@ -1180,7 +1180,7 @@ impl<'p, 'tcx> Fields<'p, 'tcx> {
             if is_uninhabited && (!is_visible || is_non_exhaustive) {
                 None
             } else {
-                Some((Field::new(i), ty))
+                Some((FieldIdx::new(i), ty))
             }
         })
     }
@@ -1438,7 +1438,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                 ty::Tuple(..) => PatKind::Leaf {
                     subpatterns: subpatterns
                         .enumerate()
-                        .map(|(i, pattern)| FieldPat { field: Field::new(i), pattern })
+                        .map(|(i, pattern)| FieldPat { field: FieldIdx::new(i), pattern })
                         .collect(),
                 },
                 ty::Adt(adt_def, _) if adt_def.is_box() => {
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
index f356c8a68380c..72b4041aa1b72 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -21,12 +21,13 @@ use rustc_middle::mir::interpret::{
     ConstValue, ErrorHandled, LitToConstError, LitToConstInput, Scalar,
 };
 use rustc_middle::mir::{self, UserTypeProjection};
-use rustc_middle::mir::{BorrowKind, Field, Mutability};
+use rustc_middle::mir::{BorrowKind, Mutability};
 use rustc_middle::thir::{Ascription, BindingMode, FieldPat, LocalVarId, Pat, PatKind, PatRange};
 use rustc_middle::ty::subst::{GenericArg, SubstsRef};
 use rustc_middle::ty::CanonicalUserTypeAnnotation;
 use rustc_middle::ty::{self, AdtDef, ConstKind, Region, Ty, TyCtxt, UserType};
 use rustc_span::{Span, Symbol};
+use rustc_target::abi::FieldIdx;
 
 use std::cmp::Ordering;
 
@@ -356,7 +357,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 let subpatterns = fields
                     .iter()
                     .map(|field| FieldPat {
-                        field: Field::new(self.typeck_results.field_index(field.hir_id)),
+                        field: FieldIdx::new(self.typeck_results.field_index(field.hir_id)),
                         pattern: self.lower_pattern(&field.pat),
                     })
                     .collect();
@@ -379,7 +380,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         pats.iter()
             .enumerate_and_adjust(expected_len, gap_pos)
             .map(|(i, subpattern)| FieldPat {
-                field: Field::new(i),
+                field: FieldIdx::new(i),
                 pattern: self.lower_pattern(subpattern),
             })
             .collect()
@@ -723,7 +724,7 @@ macro_rules! ClonePatternFoldableImpls {
 }
 
 ClonePatternFoldableImpls! { <'tcx>
-    Span, Field, Mutability, Symbol, LocalVarId, usize,
+    Span, FieldIdx, Mutability, Symbol, LocalVarId, usize,
     Region<'tcx>, Ty<'tcx>, BindingMode, AdtDef<'tcx>,
     SubstsRef<'tcx>, &'tcx GenericArg<'tcx>, UserType<'tcx>,
     UserTypeProjection, CanonicalUserTypeAnnotation<'tcx>
diff --git a/compiler/rustc_mir_dataflow/src/elaborate_drops.rs b/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
index fe6728fc76e4c..37787d99c2d51 100644
--- a/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
@@ -7,7 +7,7 @@ use rustc_middle::traits::Reveal;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::util::IntTypeExt;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_target::abi::{VariantIdx, FIRST_VARIANT};
+use rustc_target::abi::{FieldIdx, VariantIdx, FIRST_VARIANT};
 use std::{fmt, iter};
 
 /// The value of an inserted drop flag.
@@ -129,7 +129,7 @@ pub trait DropElaborator<'a, 'tcx>: fmt::Debug {
     /// Returns the subpath of a field of `path` (or `None` if there is no dedicated subpath).
     ///
     /// If this returns `None`, `field` will not get a dedicated drop flag.
-    fn field_subpath(&self, path: Self::Path, field: Field) -> Option<Self::Path>;
+    fn field_subpath(&self, path: Self::Path, field: FieldIdx) -> Option<Self::Path>;
 
     /// Returns the subpath of a dereference of `path` (or `None` if there is no dedicated subpath).
     ///
@@ -269,7 +269,7 @@ where
             .iter()
             .enumerate()
             .map(|(i, f)| {
-                let field = Field::new(i);
+                let field = FieldIdx::new(i);
                 let subpath = self.elaborator.field_subpath(variant_path, field);
                 let tcx = self.tcx();
 
@@ -397,8 +397,8 @@ where
             .enumerate()
             .map(|(i, &ty)| {
                 (
-                    self.tcx().mk_place_field(self.place, Field::new(i), ty),
-                    self.elaborator.field_subpath(self.path, Field::new(i)),
+                    self.tcx().mk_place_field(self.place, FieldIdx::new(i), ty),
+                    self.elaborator.field_subpath(self.path, FieldIdx::new(i)),
                 )
             })
             .collect();
@@ -416,9 +416,9 @@ where
             unique_ty.ty_adt_def().unwrap().non_enum_variant().fields[0].ty(self.tcx(), substs);
         let ptr_ty = self.tcx().mk_imm_ptr(substs[0].expect_ty());
 
-        let unique_place = self.tcx().mk_place_field(self.place, Field::new(0), unique_ty);
-        let nonnull_place = self.tcx().mk_place_field(unique_place, Field::new(0), nonnull_ty);
-        let ptr_place = self.tcx().mk_place_field(nonnull_place, Field::new(0), ptr_ty);
+        let unique_place = self.tcx().mk_place_field(self.place, FieldIdx::new(0), unique_ty);
+        let nonnull_place = self.tcx().mk_place_field(unique_place, FieldIdx::new(0), nonnull_ty);
+        let ptr_place = self.tcx().mk_place_field(nonnull_place, FieldIdx::new(0), ptr_ty);
         let interior = self.tcx().mk_place_deref(ptr_place);
 
         let interior_path = self.elaborator.deref_subpath(self.path);
@@ -899,7 +899,7 @@ where
             .iter()
             .enumerate()
             .map(|(i, f)| {
-                let field = Field::new(i);
+                let field = FieldIdx::new(i);
                 let field_ty = f.ty(tcx, substs);
                 Operand::Move(tcx.mk_place_field(self.place, field, field_ty))
             })
diff --git a/compiler/rustc_mir_dataflow/src/value_analysis.rs b/compiler/rustc_mir_dataflow/src/value_analysis.rs
index 7f560d6119428..63e553bec5329 100644
--- a/compiler/rustc_mir_dataflow/src/value_analysis.rs
+++ b/compiler/rustc_mir_dataflow/src/value_analysis.rs
@@ -40,7 +40,7 @@ use rustc_index::vec::IndexVec;
 use rustc_middle::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 
 use crate::lattice::{HasBottom, HasTop};
 use crate::{
@@ -919,7 +919,7 @@ impl<V: HasTop> ValueOrPlace<V> {
 /// Although only field projections are currently allowed, this could change in the future.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum TrackElem {
-    Field(Field),
+    Field(FieldIdx),
     Variant(VariantIdx),
     Discriminant,
 }
@@ -941,7 +941,7 @@ pub fn iter_fields<'tcx>(
     ty: Ty<'tcx>,
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
-    mut f: impl FnMut(Option<VariantIdx>, Field, Ty<'tcx>),
+    mut f: impl FnMut(Option<VariantIdx>, FieldIdx, Ty<'tcx>),
 ) {
     match ty.kind() {
         ty::Tuple(list) => {
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index a7218a4f2500d..15f5df41153b2 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -13,8 +13,7 @@ use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_mir_dataflow::value_analysis::{Map, State, TrackElem, ValueAnalysis, ValueOrPlace};
 use rustc_mir_dataflow::{lattice::FlatSet, Analysis, ResultsVisitor, SwitchIntEdgeEffects};
 use rustc_span::DUMMY_SP;
-use rustc_target::abi::Align;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{Align, FieldIdx, VariantIdx};
 
 use crate::MirPass;
 
@@ -148,7 +147,7 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'_, 'tcx> {
                         for (field_index, operand) in operands.iter().enumerate() {
                             if let Some(field) = self.map().apply(
                                 variant_target_idx,
-                                TrackElem::Field(Field::from_usize(field_index)),
+                                TrackElem::Field(FieldIdx::from_usize(field_index)),
                             ) {
                                 let result = self.handle_operand(operand, state);
                                 state.insert_idx(field, result, self.map());
diff --git a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
index 954bb5aff8de6..58bc083280a30 100644
--- a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
@@ -9,6 +9,7 @@ use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{Ty, TyCtxt};
+use rustc_target::abi::FieldIdx;
 
 /// Constructs the types used when accessing a Box's pointer
 pub fn build_ptr_tys<'tcx>(
@@ -32,9 +33,9 @@ pub fn build_projection<'tcx>(
     ptr_ty: Ty<'tcx>,
 ) -> [PlaceElem<'tcx>; 3] {
     [
-        PlaceElem::Field(Field::new(0), unique_ty),
-        PlaceElem::Field(Field::new(0), nonnull_ty),
-        PlaceElem::Field(Field::new(0), ptr_ty),
+        PlaceElem::Field(FieldIdx::new(0), unique_ty),
+        PlaceElem::Field(FieldIdx::new(0), nonnull_ty),
+        PlaceElem::Field(FieldIdx::new(0), ptr_ty),
     ]
 }
 
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index 3faccca823a57..a028d6356d50e 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -15,7 +15,7 @@ use rustc_mir_dataflow::MoveDataParamEnv;
 use rustc_mir_dataflow::{on_all_children_bits, on_all_drop_children_bits};
 use rustc_mir_dataflow::{Analysis, ResultsCursor};
 use rustc_span::{DesugaringKind, Span};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use std::fmt;
 
 /// During MIR building, Drop terminators are inserted in every place where a drop may occur.
@@ -252,7 +252,7 @@ impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, 'tcx> {
         }
     }
 
-    fn field_subpath(&self, path: Self::Path, field: Field) -> Option<Self::Path> {
+    fn field_subpath(&self, path: Self::Path, field: FieldIdx) -> Option<Self::Path> {
         rustc_mir_dataflow::move_path_children_matching(self.ctxt.move_data(), path, |e| match e {
             ProjectionElem::Field(idx, _) => idx == field,
             _ => false,
diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs
index 8a6360114dc54..50538248d91ee 100644
--- a/compiler/rustc_mir_transform/src/generator.rs
+++ b/compiler/rustc_mir_transform/src/generator.rs
@@ -73,7 +73,7 @@ use rustc_mir_dataflow::{self, Analysis};
 use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_target::spec::PanicStrategy;
 use std::{iter, ops};
 
@@ -162,9 +162,10 @@ impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {
                 place,
                 Place {
                     local: SELF_ARG,
-                    projection: self
-                        .tcx()
-                        .mk_place_elems(&[ProjectionElem::Field(Field::new(0), self.ref_gen_ty)]),
+                    projection: self.tcx().mk_place_elems(&[ProjectionElem::Field(
+                        FieldIdx::new(0),
+                        self.ref_gen_ty,
+                    )]),
                 },
                 self.tcx,
             );
@@ -297,7 +298,7 @@ impl<'tcx> TransformVisitor<'tcx> {
         let self_place = Place::from(SELF_ARG);
         let base = self.tcx.mk_place_downcast_unnamed(self_place, variant_index);
         let mut projection = base.projection.to_vec();
-        projection.push(ProjectionElem::Field(Field::new(idx), ty));
+        projection.push(ProjectionElem::Field(FieldIdx::new(idx), ty));
 
         Place { local: base.local, projection: self.tcx.mk_place_elems(&projection) }
     }
@@ -967,7 +968,7 @@ fn compute_layout<'tcx>(
 
     // Build the generator variant field list.
     // Create a map from local indices to generator struct indices.
-    let mut variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>> =
+    let mut variant_fields: IndexVec<VariantIdx, IndexVec<FieldIdx, GeneratorSavedLocal>> =
         iter::repeat(IndexVec::new()).take(RESERVED_VARIANTS).collect();
     let mut remap = FxHashMap::default();
     for (suspension_point_idx, live_locals) in live_locals_at_suspension_points.iter().enumerate() {
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 5c7415192b936..98d2df7197864 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -10,7 +10,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
 use rustc_session::config::OptLevel;
 use rustc_span::{hygiene::ExpnKind, ExpnData, LocalExpnId, Span};
-use rustc_target::abi::FIRST_VARIANT;
+use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
 use rustc_target::spec::abi::Abi;
 
 use crate::simplify::{remove_dead_blocks, CfgSimplifier};
@@ -701,7 +701,7 @@ impl<'tcx> Inliner<'tcx> {
             // The `tmp0`, `tmp1`, and `tmp2` in our example above.
             let tuple_tmp_args = tuple_tys.iter().enumerate().map(|(i, ty)| {
                 // This is e.g., `tuple_tmp.0` in our example above.
-                let tuple_field = Operand::Move(tcx.mk_place_field(tuple, Field::new(i), ty));
+                let tuple_field = Operand::Move(tcx.mk_place_field(tuple, FieldIdx::new(i), ty));
 
                 // Spill to a local to make e.g., `tmp0`.
                 self.create_temp_if_necessary(tuple_field, callsite, caller_body)
diff --git a/compiler/rustc_mir_transform/src/instcombine.rs b/compiler/rustc_mir_transform/src/instcombine.rs
index c9750e899a51e..3d06a0a495f79 100644
--- a/compiler/rustc_mir_transform/src/instcombine.rs
+++ b/compiler/rustc_mir_transform/src/instcombine.rs
@@ -3,14 +3,14 @@
 use crate::MirPass;
 use rustc_hir::Mutability;
 use rustc_middle::mir::{
-    BinOp, Body, CastKind, Constant, ConstantKind, Field, LocalDecls, Operand, Place,
-    ProjectionElem, Rvalue, SourceInfo, Statement, StatementKind, SwitchTargets, Terminator,
-    TerminatorKind, UnOp,
+    BinOp, Body, CastKind, Constant, ConstantKind, LocalDecls, Operand, Place, ProjectionElem,
+    Rvalue, SourceInfo, Statement, StatementKind, SwitchTargets, Terminator, TerminatorKind, UnOp,
 };
 use rustc_middle::ty::layout::ValidityRequirement;
 use rustc_middle::ty::util::IntTypeExt;
 use rustc_middle::ty::{self, ParamEnv, SubstsRef, Ty, TyCtxt};
 use rustc_span::symbol::Symbol;
+use rustc_target::abi::FieldIdx;
 
 pub struct InstCombine;
 
@@ -187,7 +187,7 @@ impl<'tcx> InstCombineContext<'tcx, '_> {
                     for (i, field) in variant.fields.iter().enumerate() {
                         let field_ty = field.ty(self.tcx, substs);
                         if field_ty == *cast_ty {
-                            let place = place.project_deeper(&[ProjectionElem::Field(Field::from_usize(i), *cast_ty)], self.tcx);
+                            let place = place.project_deeper(&[ProjectionElem::Field(FieldIdx::from_usize(i), *cast_ty)], self.tcx);
                             let operand = if operand.is_move() { Operand::Move(place) } else { Operand::Copy(place) };
                             *rvalue = Rvalue::Use(operand);
                             return;
diff --git a/compiler/rustc_mir_transform/src/lower_intrinsics.rs b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
index 6a7ceb8fef73f..c136642dff277 100644
--- a/compiler/rustc_mir_transform/src/lower_intrinsics.rs
+++ b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
@@ -6,7 +6,7 @@ use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 
 pub struct LowerIntrinsics;
 
@@ -211,7 +211,7 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
                                                     Some(sym::Some),
                                                     VariantIdx::from_u32(1),
                                                 ),
-                                                PlaceElem::Field(Field::from_u32(0), *dest_ty),
+                                                PlaceElem::Field(FieldIdx::from_u32(0), *dest_ty),
                                             ],
                                             tcx,
                                         ),
diff --git a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
index e72729b152e69..1f9e521d315d8 100644
--- a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
+++ b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
@@ -1,10 +1,11 @@
 use rustc_index::bit_set::ChunkedBitSet;
-use rustc_middle::mir::{Body, Field, TerminatorKind};
+use rustc_middle::mir::{Body, TerminatorKind};
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, VariantDef};
 use rustc_mir_dataflow::impls::MaybeInitializedPlaces;
 use rustc_mir_dataflow::move_paths::{LookupResult, MoveData, MovePathIndex};
 use rustc_mir_dataflow::{self, move_path_children_matching, Analysis, MoveDataParamEnv};
+use rustc_target::abi::FieldIdx;
 
 use crate::MirPass;
 
@@ -130,7 +131,7 @@ fn is_needs_drop_and_init<'tcx>(
                     .fields
                     .iter()
                     .enumerate()
-                    .map(|(f, field)| (Field::from_usize(f), field.ty(tcx, substs), mpi))
+                    .map(|(f, field)| (FieldIdx::from_usize(f), field.ty(tcx, substs), mpi))
                     .any(field_needs_drop_and_init)
             })
         }
@@ -138,7 +139,7 @@ fn is_needs_drop_and_init<'tcx>(
         ty::Tuple(fields) => fields
             .iter()
             .enumerate()
-            .map(|(f, f_ty)| (Field::from_usize(f), f_ty, mpi))
+            .map(|(f, f_ty)| (FieldIdx::from_usize(f), f_ty, mpi))
             .any(field_needs_drop_and_init),
 
         _ => true,
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
index 2ef5c1062fe28..9e406eba0fcaa 100644
--- a/compiler/rustc_mir_transform/src/shim.rs
+++ b/compiler/rustc_mir_transform/src/shim.rs
@@ -5,7 +5,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, EarlyBinder, GeneratorSubsts, Ty, TyCtxt};
-use rustc_target::abi::{VariantIdx, FIRST_VARIANT};
+use rustc_target::abi::{FieldIdx, VariantIdx, FIRST_VARIANT};
 
 use rustc_index::vec::{Idx, IndexVec};
 
@@ -309,7 +309,7 @@ impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> {
 
     fn clear_drop_flag(&mut self, _location: Location, _path: Self::Path, _mode: DropFlagMode) {}
 
-    fn field_subpath(&self, _path: Self::Path, _field: Field) -> Option<Self::Path> {
+    fn field_subpath(&self, _path: Self::Path, _field: FieldIdx) -> Option<Self::Path> {
         None
     }
     fn deref_subpath(&self, _path: Self::Path) -> Option<Self::Path> {
@@ -530,7 +530,7 @@ impl<'tcx> CloneShimBuilder<'tcx> {
             // created by block 2*i. We store this block in `unwind` so that the next clone block
             // will unwind to it if cloning fails.
 
-            let field = Field::new(i);
+            let field = FieldIdx::new(i);
             let src_field = self.tcx.mk_place_field(src, field, ity);
 
             let dest_field = self.tcx.mk_place_field(dest, field, ity);
@@ -753,7 +753,7 @@ fn build_call_shim<'tcx>(
     if let Some(untuple_args) = untuple_args {
         let tuple_arg = Local::new(1 + (sig.inputs().len() - 1));
         args.extend(untuple_args.iter().enumerate().map(|(i, ity)| {
-            Operand::Move(tcx.mk_place_field(Place::from(tuple_arg), Field::new(i), *ity))
+            Operand::Move(tcx.mk_place_field(Place::from(tuple_arg), FieldIdx::new(i), *ity))
         }));
     }
 
diff --git a/compiler/rustc_mir_transform/src/sroa.rs b/compiler/rustc_mir_transform/src/sroa.rs
index ca2221520c825..c798bd05345e2 100644
--- a/compiler/rustc_mir_transform/src/sroa.rs
+++ b/compiler/rustc_mir_transform/src/sroa.rs
@@ -6,6 +6,7 @@ use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_mir_dataflow::value_analysis::{excluded_locals, iter_fields};
+use rustc_target::abi::FieldIdx;
 
 pub struct ScalarReplacementOfAggregates;
 
@@ -115,7 +116,7 @@ fn escaping_locals(excluded: &BitSet<Local>, body: &Body<'_>) -> BitSet<Local> {
 struct ReplacementMap<'tcx> {
     /// Pre-computed list of all "new" locals for each "old" local. This is used to expand storage
     /// and deinit statement and debuginfo.
-    fragments: IndexVec<Local, Option<IndexVec<Field, Option<(Ty<'tcx>, Local)>>>>,
+    fragments: IndexVec<Local, Option<IndexVec<FieldIdx, Option<(Ty<'tcx>, Local)>>>>,
 }
 
 impl<'tcx> ReplacementMap<'tcx> {
@@ -129,7 +130,7 @@ impl<'tcx> ReplacementMap<'tcx> {
     fn place_fragments(
         &self,
         place: Place<'tcx>,
-    ) -> Option<impl Iterator<Item = (Field, Ty<'tcx>, Local)> + '_> {
+    ) -> Option<impl Iterator<Item = (FieldIdx, Ty<'tcx>, Local)> + '_> {
         let local = place.as_local()?;
         let fields = self.fragments[local].as_ref()?;
         Some(fields.iter_enumerated().filter_map(|(field, &opt_ty_local)| {
diff --git a/compiler/rustc_trait_selection/src/solve/assembly.rs b/compiler/rustc_trait_selection/src/solve/assembly.rs
index 0f7a0eb337ba6..856b1c08b7237 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly.rs
@@ -6,6 +6,7 @@ use super::trait_goals::structural_traits::*;
 use super::{EvalCtxt, SolverMode};
 use crate::traits::coherence;
 use itertools::Itertools;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir::def_id::DefId;
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::util::elaborate_predicates;
@@ -489,9 +490,21 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         };
 
         let tcx = self.tcx();
-        for assumption in
-            elaborate_predicates(tcx, bounds.iter().map(|bound| bound.with_self_ty(tcx, self_ty)))
-        {
+        let own_bounds: FxIndexSet<_> =
+            bounds.iter().map(|bound| bound.with_self_ty(tcx, self_ty)).collect();
+        for assumption in elaborate_predicates(tcx, own_bounds.iter().copied()) {
+            // FIXME: Predicates are fully elaborated in the object type's existential bounds
+            // list. We want to only consider these pre-elaborated projections, and not other
+            // projection predicates that we reach by elaborating the principal trait ref,
+            // since that'll cause ambiguity.
+            //
+            // We can remove this when we have implemented intersections in responses.
+            if assumption.to_opt_poly_projection_pred().is_some()
+                && !own_bounds.contains(&assumption)
+            {
+                continue;
+            }
+
             match G::consider_object_bound_candidate(self, goal, assumption) {
                 Ok(result) => {
                     candidates.push(Candidate { source: CandidateSource::BuiltinImpl, result })
diff --git a/compiler/rustc_trait_selection/src/solve/canonical/canonicalize.rs b/compiler/rustc_trait_selection/src/solve/canonicalize.rs
similarity index 100%
rename from compiler/rustc_trait_selection/src/solve/canonical/canonicalize.rs
rename to compiler/rustc_trait_selection/src/solve/canonicalize.rs
diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs
index e47b5ae21b5af..e64b4a7656f25 100644
--- a/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs
@@ -6,9 +6,9 @@ use rustc_infer::infer::{
     DefineOpaqueTypes, InferCtxt, InferOk, LateBoundRegionConversionTime, TyCtxtInferExt,
 };
 use rustc_infer::traits::query::NoSolution;
-use rustc_infer::traits::solve::{CanonicalGoal, Certainty, MaybeCause, QueryResult};
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
+use rustc_middle::traits::solve::{CanonicalGoal, Certainty, MaybeCause, QueryResult};
 use rustc_middle::ty::{
     self, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
     TypeVisitor,
@@ -16,13 +16,32 @@ use rustc_middle::ty::{
 use rustc_span::DUMMY_SP;
 use std::ops::ControlFlow;
 
+use crate::traits::specialization_graph;
+
 use super::search_graph::{self, OverflowHandler};
 use super::SolverMode;
 use super::{search_graph::SearchGraph, Goal};
 
+mod canonical;
+
 pub struct EvalCtxt<'a, 'tcx> {
-    // FIXME: should be private.
-    pub(super) infcx: &'a InferCtxt<'tcx>,
+    /// The inference context that backs (mostly) inference and placeholder terms
+    /// instantiated while solving goals.
+    ///
+    /// NOTE: The `InferCtxt` that backs the `EvalCtxt` is intentionally private,
+    /// because the `InferCtxt` is much more general than `EvalCtxt`. Methods such
+    /// as  `take_registered_region_obligations` can mess up query responses,
+    /// using `At::normalize` is totally wrong, calling `evaluate_root_goal` can
+    /// cause coinductive unsoundness, etc.
+    ///
+    /// Methods that are generally of use for trait solving are *intentionally*
+    /// re-declared through the `EvalCtxt` below, often with cleaner signatures
+    /// since we don't care about things like `ObligationCause`s and `Span`s here.
+    /// If some `InferCtxt` method is missing, please first think defensively about
+    /// the method's compatibility with this solver, or if an existing one does
+    /// the job already.
+    infcx: &'a InferCtxt<'tcx>,
+
     pub(super) var_values: CanonicalVarValues<'tcx>,
     /// The highest universe index nameable by the caller.
     ///
@@ -393,7 +412,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                 if let &ty::Infer(ty::TyVar(vid)) = ty.kind() {
                     match self.infcx.probe_ty_var(vid) {
                         Ok(value) => bug!("resolved var in query: {goal:?} {value:?}"),
-                        Err(universe) => universe == self.universe(),
+                        Err(universe) => universe == self.infcx.universe(),
                     }
                 } else {
                     false
@@ -403,7 +422,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                 if let ty::ConstKind::Infer(ty::InferConst::Var(vid)) = ct.kind() {
                     match self.infcx.probe_const_var(vid) {
                         Ok(value) => bug!("resolved var in query: {goal:?} {value:?}"),
-                        Err(universe) => universe == self.universe(),
+                        Err(universe) => universe == self.infcx.universe(),
                     }
                 } else {
                     false
@@ -545,7 +564,43 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         self.infcx.fresh_substs_for_item(DUMMY_SP, def_id)
     }
 
-    pub(super) fn universe(&self) -> ty::UniverseIndex {
-        self.infcx.universe()
+    pub(super) fn translate_substs(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        source_impl: DefId,
+        source_substs: ty::SubstsRef<'tcx>,
+        target_node: specialization_graph::Node,
+    ) -> ty::SubstsRef<'tcx> {
+        crate::traits::translate_substs(
+            self.infcx,
+            param_env,
+            source_impl,
+            source_substs,
+            target_node,
+        )
+    }
+
+    pub(super) fn register_ty_outlives(&self, ty: Ty<'tcx>, lt: ty::Region<'tcx>) {
+        self.infcx.register_region_obligation_with_cause(ty, lt, &ObligationCause::dummy());
+    }
+
+    pub(super) fn register_region_outlives(&self, a: ty::Region<'tcx>, b: ty::Region<'tcx>) {
+        // `b : a` ==> `a <= b`
+        // (inlined from `InferCtxt::region_outlives_predicate`)
+        self.infcx.sub_regions(
+            rustc_infer::infer::SubregionOrigin::RelateRegionParamBound(DUMMY_SP),
+            b,
+            a,
+        );
+    }
+
+    /// Computes the list of goals required for `arg` to be well-formed
+    pub(super) fn well_formed_goals(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        arg: ty::GenericArg<'tcx>,
+    ) -> Option<impl Iterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>> {
+        crate::traits::wf::unnormalized_obligations(self.infcx, param_env, arg)
+            .map(|obligations| obligations.into_iter().map(|obligation| obligation.into()))
     }
 }
diff --git a/compiler/rustc_trait_selection/src/solve/canonical/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs
similarity index 92%
rename from compiler/rustc_trait_selection/src/solve/canonical/mod.rs
rename to compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs
index efecaf33ef987..ee90488730a64 100644
--- a/compiler/rustc_trait_selection/src/solve/canonical/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs
@@ -8,22 +8,19 @@
 /// section of the [rustc-dev-guide][c].
 ///
 /// [c]: https://rustc-dev-guide.rust-lang.org/solve/canonicalization.html
-use self::canonicalize::{CanonicalizeMode, Canonicalizer};
 use super::{CanonicalGoal, Certainty, EvalCtxt, Goal};
-use super::{CanonicalResponse, ExternalConstraints, QueryResult, Response};
+use crate::solve::canonicalize::{CanonicalizeMode, Canonicalizer};
+use crate::solve::{CanonicalResponse, QueryResult, Response};
 use rustc_infer::infer::canonical::query_response::make_query_region_constraints;
 use rustc_infer::infer::canonical::CanonicalVarValues;
 use rustc_infer::infer::canonical::{CanonicalExt, QueryRegionConstraints};
-use rustc_infer::traits::query::NoSolution;
-use rustc_infer::traits::solve::ExternalConstraintsData;
-use rustc_infer::traits::ObligationCause;
+use rustc_middle::traits::query::NoSolution;
+use rustc_middle::traits::solve::{ExternalConstraints, ExternalConstraintsData};
 use rustc_middle::ty::{self, GenericArgKind};
 use rustc_span::DUMMY_SP;
 use std::iter;
 use std::ops::Deref;
 
-mod canonicalize;
-
 impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// Canonicalizes the goal remembering the original values
     /// for each bound variable.
@@ -48,7 +45,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// - `external_constraints`: additional constraints which aren't expressable
     ///   using simple unification of inference variables.
     #[instrument(level = "debug", skip(self))]
-    pub(super) fn evaluate_added_goals_and_make_canonical_response(
+    pub(in crate::solve) fn evaluate_added_goals_and_make_canonical_response(
         &mut self,
         certainty: Certainty,
     ) -> QueryResult<'tcx> {
@@ -219,15 +216,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     fn register_region_constraints(&mut self, region_constraints: &QueryRegionConstraints<'tcx>) {
         for &(ty::OutlivesPredicate(lhs, rhs), _) in &region_constraints.outlives {
             match lhs.unpack() {
-                GenericArgKind::Lifetime(lhs) => self.infcx.region_outlives_predicate(
-                    &ObligationCause::dummy(),
-                    ty::Binder::dummy(ty::OutlivesPredicate(lhs, rhs)),
-                ),
-                GenericArgKind::Type(lhs) => self.infcx.register_region_obligation_with_cause(
-                    lhs,
-                    rhs,
-                    &ObligationCause::dummy(),
-                ),
+                GenericArgKind::Lifetime(lhs) => self.register_region_outlives(lhs, rhs),
+                GenericArgKind::Type(lhs) => self.register_ty_outlives(lhs, rhs),
                 GenericArgKind::Const(_) => bug!("const outlives: {lhs:?}: {rhs:?}"),
             }
         }
diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs
index 65e7bcb7f019d..a96ec2c60f097 100644
--- a/compiler/rustc_trait_selection/src/solve/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/mod.rs
@@ -13,18 +13,15 @@ use rustc_hir::def_id::DefId;
 use rustc_infer::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc_infer::traits::query::NoSolution;
 use rustc_middle::traits::solve::{
-    CanonicalGoal, CanonicalResponse, Certainty, ExternalConstraints, ExternalConstraintsData,
-    Goal, QueryResult, Response,
+    CanonicalResponse, Certainty, ExternalConstraintsData, Goal, QueryResult, Response,
 };
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::ty::{
     CoercePredicate, RegionOutlivesPredicate, SubtypePredicate, TypeOutlivesPredicate,
 };
 
-use crate::traits::ObligationCause;
-
 mod assembly;
-mod canonical;
+mod canonicalize;
 mod eval_ctxt;
 mod fulfill;
 mod project_goals;
@@ -66,7 +63,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         goal: Goal<'tcx, TypeOutlivesPredicate<'tcx>>,
     ) -> QueryResult<'tcx> {
         let ty::OutlivesPredicate(ty, lt) = goal.predicate;
-        self.infcx.register_region_obligation_with_cause(ty, lt, &ObligationCause::dummy());
+        self.register_ty_outlives(ty, lt);
         self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
     }
 
@@ -75,10 +72,8 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         &mut self,
         goal: Goal<'tcx, RegionOutlivesPredicate<'tcx>>,
     ) -> QueryResult<'tcx> {
-        self.infcx.region_outlives_predicate(
-            &ObligationCause::dummy(),
-            ty::Binder::dummy(goal.predicate),
-        );
+        let ty::OutlivesPredicate(a, b) = goal.predicate;
+        self.register_region_outlives(a, b);
         self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
     }
 
@@ -142,13 +137,9 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         &mut self,
         goal: Goal<'tcx, ty::GenericArg<'tcx>>,
     ) -> QueryResult<'tcx> {
-        match crate::traits::wf::unnormalized_obligations(
-            self.infcx,
-            goal.param_env,
-            goal.predicate,
-        ) {
-            Some(obligations) => {
-                self.add_goals(obligations.into_iter().map(|o| o.into()));
+        match self.well_formed_goals(goal.param_env, goal.predicate) {
+            Some(goals) => {
+                self.add_goals(goals);
                 self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
             }
             None => self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS),
diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs
index 91b56fe3522ca..48f7d3e3e4023 100644
--- a/compiler/rustc_trait_selection/src/solve/project_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs
@@ -1,4 +1,4 @@
-use crate::traits::{specialization_graph, translate_substs};
+use crate::traits::specialization_graph;
 
 use super::assembly;
 use super::trait_goals::structural_traits;
@@ -7,7 +7,6 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_hir::LangItem;
-use rustc_infer::infer::InferCtxt;
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::specialization_graph::LeafDef;
 use rustc_infer::traits::Reveal;
@@ -165,7 +164,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
             // return ambiguity this would otherwise be incomplete, resulting in
             // unsoundness during coherence (#105782).
             let Some(assoc_def) = fetch_eligible_assoc_item_def(
-                ecx.infcx,
+                ecx,
                 goal.param_env,
                 goal_trait_ref,
                 goal.predicate.def_id(),
@@ -196,8 +195,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
                 goal_trait_ref.def_id,
                 impl_substs,
             );
-            let substs = translate_substs(
-                ecx.infcx,
+            let substs = ecx.translate_substs(
                 goal.param_env,
                 impl_def_id,
                 impl_substs_with_gat,
@@ -504,15 +502,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
 ///
 /// FIXME: We should merge these 3 implementations as it's likely that they otherwise
 /// diverge.
-#[instrument(level = "debug", skip(infcx, param_env), ret)]
+#[instrument(level = "debug", skip(ecx, param_env), ret)]
 fn fetch_eligible_assoc_item_def<'tcx>(
-    infcx: &InferCtxt<'tcx>,
+    ecx: &EvalCtxt<'_, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     goal_trait_ref: ty::TraitRef<'tcx>,
     trait_assoc_def_id: DefId,
     impl_def_id: DefId,
 ) -> Result<Option<LeafDef>, NoSolution> {
-    let node_item = specialization_graph::assoc_def(infcx.tcx, impl_def_id, trait_assoc_def_id)
+    let node_item = specialization_graph::assoc_def(ecx.tcx(), impl_def_id, trait_assoc_def_id)
         .map_err(|ErrorGuaranteed { .. }| NoSolution)?;
 
     let eligible = if node_item.is_final() {
@@ -524,7 +522,7 @@ fn fetch_eligible_assoc_item_def<'tcx>(
         // transmute checking and polymorphic MIR optimizations could
         // get a result which isn't correct for all monomorphizations.
         if param_env.reveal() == Reveal::All {
-            let poly_trait_ref = infcx.resolve_vars_if_possible(goal_trait_ref);
+            let poly_trait_ref = ecx.resolve_vars_if_possible(goal_trait_ref);
             !poly_trait_ref.still_further_specializable()
         } else {
             debug!(?node_item.item.def_id, "not eligible due to default");
diff --git a/library/alloc/src/alloc.rs b/library/alloc/src/alloc.rs
index 3a797bd5ecaa8..6f2ba957bcda0 100644
--- a/library/alloc/src/alloc.rs
+++ b/library/alloc/src/alloc.rs
@@ -14,8 +14,6 @@ use core::ptr::{self, NonNull};
 #[doc(inline)]
 pub use core::alloc::*;
 
-use core::marker::Destruct;
-
 #[cfg(test)]
 mod tests;
 
@@ -331,16 +329,12 @@ unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
 
 #[cfg_attr(not(test), lang = "box_free")]
 #[inline]
-#[rustc_const_unstable(feature = "const_box", issue = "92521")]
 // This signature has to be the same as `Box`, otherwise an ICE will happen.
 // When an additional parameter to `Box` is added (like `A: Allocator`), this has to be added here as
 // well.
 // For example if `Box` is changed to  `struct Box<T: ?Sized, A: Allocator>(Unique<T>, A)`,
 // this function has to be changed to `fn box_free<T: ?Sized, A: Allocator>(Unique<T>, A)` as well.
-pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Destruct>(
-    ptr: Unique<T>,
-    alloc: A,
-) {
+pub(crate) unsafe fn box_free<T: ?Sized, A: Allocator>(ptr: Unique<T>, alloc: A) {
     unsafe {
         let size = size_of_val(ptr.as_ref());
         let align = min_align_of_val(ptr.as_ref());
diff --git a/library/alloc/src/borrow.rs b/library/alloc/src/borrow.rs
index 83a1385599bec..0c8c796ae9b81 100644
--- a/library/alloc/src/borrow.rs
+++ b/library/alloc/src/borrow.rs
@@ -328,10 +328,9 @@ impl<B: ?Sized + ToOwned> Cow<'_, B> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_deref", issue = "88955")]
-impl<B: ?Sized + ToOwned> const Deref for Cow<'_, B>
+impl<B: ?Sized + ToOwned> Deref for Cow<'_, B>
 where
-    B::Owned: ~const Borrow<B>,
+    B::Owned: Borrow<B>,
 {
     type Target = B;
 
diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index 241b11c3f5f52..09041bb119bb7 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -159,7 +159,7 @@ use core::hash::{Hash, Hasher};
 use core::iter::FromIterator;
 use core::iter::{FusedIterator, Iterator};
 use core::marker::Tuple;
-use core::marker::{Destruct, Unpin, Unsize};
+use core::marker::{Unpin, Unsize};
 use core::mem;
 use core::ops::{
     CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Generator, GeneratorState, Receiver,
@@ -376,12 +376,11 @@ impl<T, A: Allocator> Box<T, A> {
     /// ```
     #[cfg(not(no_global_oom_handling))]
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[must_use]
     #[inline]
-    pub const fn new_in(x: T, alloc: A) -> Self
+    pub fn new_in(x: T, alloc: A) -> Self
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let mut boxed = Self::new_uninit_in(alloc);
         unsafe {
@@ -406,12 +405,10 @@ impl<T, A: Allocator> Box<T, A> {
     /// # Ok::<(), std::alloc::AllocError>(())
     /// ```
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>
+    pub fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>
     where
-        T: ~const Destruct,
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let mut boxed = Self::try_new_uninit_in(alloc)?;
         unsafe {
@@ -441,13 +438,12 @@ impl<T, A: Allocator> Box<T, A> {
     /// assert_eq!(*five, 5)
     /// ```
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[cfg(not(no_global_oom_handling))]
     #[must_use]
     // #[unstable(feature = "new_uninit", issue = "63291")]
-    pub const fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+    pub fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
@@ -482,10 +478,9 @@ impl<T, A: Allocator> Box<T, A> {
     /// ```
     #[unstable(feature = "allocator_api", issue = "32838")]
     // #[unstable(feature = "new_uninit", issue = "63291")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-    pub const fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+    pub fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         let ptr = alloc.allocate(layout)?.cast();
@@ -513,13 +508,12 @@ impl<T, A: Allocator> Box<T, A> {
     ///
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[cfg(not(no_global_oom_handling))]
     // #[unstable(feature = "new_uninit", issue = "63291")]
     #[must_use]
-    pub const fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+    pub fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
@@ -554,10 +548,9 @@ impl<T, A: Allocator> Box<T, A> {
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[unstable(feature = "allocator_api", issue = "32838")]
     // #[unstable(feature = "new_uninit", issue = "63291")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-    pub const fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+    pub fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         let ptr = alloc.allocate_zeroed(layout)?.cast();
@@ -573,12 +566,11 @@ impl<T, A: Allocator> Box<T, A> {
     /// construct a (pinned) `Box` in a different way than with [`Box::new_in`].
     #[cfg(not(no_global_oom_handling))]
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[must_use]
     #[inline(always)]
-    pub const fn pin_in(x: T, alloc: A) -> Pin<Self>
+    pub fn pin_in(x: T, alloc: A) -> Pin<Self>
     where
-        A: 'static + ~const Allocator + ~const Destruct,
+        A: 'static + Allocator,
     {
         Self::into_pin(Self::new_in(x, alloc))
     }
@@ -605,12 +597,8 @@ impl<T, A: Allocator> Box<T, A> {
     /// assert_eq!(Box::into_inner(c), 5);
     /// ```
     #[unstable(feature = "box_into_inner", issue = "80437")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const fn into_inner(boxed: Self) -> T
-    where
-        Self: ~const Destruct,
-    {
+    pub fn into_inner(boxed: Self) -> T {
         *boxed
     }
 }
diff --git a/library/alloc/tests/boxed.rs b/library/alloc/tests/boxed.rs
index af49826ff30a3..68ebd8e35ee3d 100644
--- a/library/alloc/tests/boxed.rs
+++ b/library/alloc/tests/boxed.rs
@@ -179,18 +179,3 @@ unsafe impl const Allocator for ConstAllocator {
         self
     }
 }
-
-#[test]
-fn const_box() {
-    const VALUE: u32 = {
-        let mut boxed = Box::new_in(1u32, ConstAllocator);
-        assert!(*boxed == 1);
-
-        *boxed = 42;
-        assert!(*boxed == 42);
-
-        *Box::leak(boxed)
-    };
-
-    assert!(VALUE == 42);
-}
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 966cf57511630..c27ca642e9b1f 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -3,7 +3,6 @@
 #![feature(assert_matches)]
 #![feature(btree_drain_filter)]
 #![feature(cow_is_borrowed)]
-#![feature(const_box)]
 #![feature(const_convert)]
 #![feature(const_cow_is_borrowed)]
 #![feature(const_heap)]
diff --git a/library/std/src/sys/hermit/mod.rs b/library/std/src/sys/hermit/mod.rs
index 743e93a2fd4db..c7cb8466705cb 100644
--- a/library/std/src/sys/hermit/mod.rs
+++ b/library/std/src/sys/hermit/mod.rs
@@ -75,9 +75,18 @@ pub fn abort_internal() -> ! {
     }
 }
 
-// FIXME: just a workaround to test the system
 pub fn hashmap_random_keys() -> (u64, u64) {
-    (1, 2)
+    let mut buf = [0; 16];
+    let mut slice = &mut buf[..];
+    while !slice.is_empty() {
+        let res = cvt(unsafe { abi::read_entropy(slice.as_mut_ptr(), slice.len(), 0) })
+            .expect("failed to generate random hashmap keys");
+        slice = &mut slice[res as usize..];
+    }
+
+    let key1 = buf[..8].try_into().unwrap();
+    let key2 = buf[8..].try_into().unwrap();
+    (u64::from_ne_bytes(key1), u64::from_ne_bytes(key2))
 }
 
 // This function is needed by the panic runtime. The symbol is named in
diff --git a/src/librustdoc/passes/strip_hidden.rs b/src/librustdoc/passes/strip_hidden.rs
index 890b3e8d67f7a..a688aa14863a9 100644
--- a/src/librustdoc/passes/strip_hidden.rs
+++ b/src/librustdoc/passes/strip_hidden.rs
@@ -121,9 +121,14 @@ impl<'a, 'tcx> DocFolder for Stripper<'a, 'tcx> {
                 // strip things like impl methods but when doing so
                 // we must not add any items to the `retained` set.
                 let old = mem::replace(&mut self.update_retained, false);
-                let ret = strip_item(self.set_is_in_hidden_item_and_fold(true, i));
+                let ret = self.set_is_in_hidden_item_and_fold(true, i);
                 self.update_retained = old;
-                Some(ret)
+                if ret.is_crate() {
+                    // We don't strip the crate, even if it has `#[doc(hidden)]`.
+                    Some(ret)
+                } else {
+                    Some(strip_item(ret))
+                }
             }
             _ => {
                 let ret = self.set_is_in_hidden_item_and_fold(true, i);
diff --git a/tests/rustdoc/issue-109695-crate-doc-hidden.rs b/tests/rustdoc/issue-109695-crate-doc-hidden.rs
new file mode 100644
index 0000000000000..7a3e53a0d32eb
--- /dev/null
+++ b/tests/rustdoc/issue-109695-crate-doc-hidden.rs
@@ -0,0 +1,8 @@
+// This test ensures that even if the crate module is `#[doc(hidden)]`, the file
+// is generated.
+
+// @has 'foo/index.html'
+// @has 'foo/all.html'
+
+#![crate_name = "foo"]
+#![doc(hidden)]
diff --git a/tests/ui-fulldeps/fluent-messages/invalid-escape.ftl b/tests/ui-fulldeps/fluent-messages/invalid-escape.ftl
new file mode 100644
index 0000000000000..e28852ea0050e
--- /dev/null
+++ b/tests/ui-fulldeps/fluent-messages/invalid-escape.ftl
@@ -0,0 +1 @@
+no_crate_bad_escape = don't use \n, \', or \"
diff --git a/tests/ui-fulldeps/fluent-messages/test.rs b/tests/ui-fulldeps/fluent-messages/test.rs
index 66575eb8e30cf..1ee7227a8e992 100644
--- a/tests/ui-fulldeps/fluent-messages/test.rs
+++ b/tests/ui-fulldeps/fluent-messages/test.rs
@@ -92,3 +92,12 @@ mod missing_message_ref {
     fluent_messages! { "./missing-message-ref.ftl" }
     //~^ ERROR referenced message `message` does not exist
 }
+
+mod bad_escape {
+    use super::fluent_messages;
+
+    fluent_messages! { "./invalid-escape.ftl" }
+    //~^ ERROR invalid escape `\n`
+    //~| ERROR invalid escape `\"`
+    //~| ERROR invalid escape `\'`
+}
diff --git a/tests/ui-fulldeps/fluent-messages/test.stderr b/tests/ui-fulldeps/fluent-messages/test.stderr
index c7961ed22f2b4..8a6a4a91cc201 100644
--- a/tests/ui-fulldeps/fluent-messages/test.stderr
+++ b/tests/ui-fulldeps/fluent-messages/test.stderr
@@ -83,5 +83,29 @@ LL |     fluent_messages! { "./missing-message-ref.ftl" }
    |
    = help: you may have meant to use a variable reference (`{$message}`)
 
-error: aborting due to 10 previous errors
+error: invalid escape `\n` in Fluent resource
+  --> $DIR/test.rs:99:24
+   |
+LL |     fluent_messages! { "./invalid-escape.ftl" }
+   |                        ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: os-specific message
+
+error: invalid escape `\"` in Fluent resource
+  --> $DIR/test.rs:99:24
+   |
+LL |     fluent_messages! { "./invalid-escape.ftl" }
+   |                        ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: os-specific message
+
+error: invalid escape `\'` in Fluent resource
+  --> $DIR/test.rs:99:24
+   |
+LL |     fluent_messages! { "./invalid-escape.ftl" }
+   |                        ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: os-specific message
+
+error: aborting due to 13 previous errors
 
diff --git a/tests/ui-fulldeps/internal-lints/existing_doc_keyword.stderr b/tests/ui-fulldeps/internal-lints/existing_doc_keyword.stderr
index 4e296fff6d0ba..5110b9be08a53 100644
--- a/tests/ui-fulldeps/internal-lints/existing_doc_keyword.stderr
+++ b/tests/ui-fulldeps/internal-lints/existing_doc_keyword.stderr
@@ -1,4 +1,4 @@
-error: found non-existing keyword `tadam` used in `#[doc(keyword = \"...\")]`
+error: found non-existing keyword `tadam` used in `#[doc(keyword = "...")]`
   --> $DIR/existing_doc_keyword.rs:10:1
    |
 LL | #[doc(keyword = "tadam")]
diff --git a/tests/ui/lint/issue-109529.fixed b/tests/ui/lint/issue-109529.fixed
new file mode 100644
index 0000000000000..5ad489073eead
--- /dev/null
+++ b/tests/ui/lint/issue-109529.fixed
@@ -0,0 +1,6 @@
+// run-rustfix
+
+fn main() {
+    for _ in 0..=255 as u8 {} //~ ERROR range endpoint is out of range
+    for _ in 0..=(255 as u8) {} //~ ERROR range endpoint is out of range
+}
diff --git a/tests/ui/lint/issue-109529.rs b/tests/ui/lint/issue-109529.rs
new file mode 100644
index 0000000000000..383d7bc4cf31f
--- /dev/null
+++ b/tests/ui/lint/issue-109529.rs
@@ -0,0 +1,6 @@
+// run-rustfix
+
+fn main() {
+    for _ in 0..256 as u8 {} //~ ERROR range endpoint is out of range
+    for _ in 0..(256 as u8) {} //~ ERROR range endpoint is out of range
+}
diff --git a/tests/ui/lint/issue-109529.stderr b/tests/ui/lint/issue-109529.stderr
new file mode 100644
index 0000000000000..9e857d1b0ab5d
--- /dev/null
+++ b/tests/ui/lint/issue-109529.stderr
@@ -0,0 +1,23 @@
+error: range endpoint is out of range for `u8`
+  --> $DIR/issue-109529.rs:4:14
+   |
+LL |     for _ in 0..256 as u8 {}
+   |              ------^^^^^^
+   |              |
+   |              help: use an inclusive range instead: `0..=255`
+   |
+   = note: `#[deny(overflowing_literals)]` on by default
+
+error: range endpoint is out of range for `u8`
+  --> $DIR/issue-109529.rs:5:14
+   |
+LL |     for _ in 0..(256 as u8) {}
+   |              ^^^^^^^^^^^^^^
+   |
+help: use an inclusive range instead
+   |
+LL |     for _ in 0..=(255 as u8) {}
+   |                 + ~~~
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/traits/new-solver/dont-elaborate-for-projections.rs b/tests/ui/traits/new-solver/dont-elaborate-for-projections.rs
new file mode 100644
index 0000000000000..e608250063c0b
--- /dev/null
+++ b/tests/ui/traits/new-solver/dont-elaborate-for-projections.rs
@@ -0,0 +1,12 @@
+// compile-flags: -Ztrait-solver=next
+// check-pass
+
+trait Iter<'a, I: 'a>: Iterator<Item = &'a I> {}
+
+fn needs_iter<'a, T: Iter<'a, I> + ?Sized, I: 'a>(_: &T) {}
+
+fn test(x: &dyn Iter<'_, ()>) {
+    needs_iter(x);
+}
+
+fn main() {}
diff --git a/tests/ui/traits/new-solver/more-object-bound.rs b/tests/ui/traits/new-solver/more-object-bound.rs
index 712759ef0e612..bb730b18ef77b 100644
--- a/tests/ui/traits/new-solver/more-object-bound.rs
+++ b/tests/ui/traits/new-solver/more-object-bound.rs
@@ -10,7 +10,7 @@ trait Trait: SuperTrait<A = <Self as SuperTrait>::B> {}
 
 fn transmute<A, B>(x: A) -> B {
     foo::<A, B, dyn Trait<A = A, B = B>>(x)
-    //~^ ERROR type annotations needed: cannot satisfy `dyn Trait<A = A, B = B>: Trait`
+    //~^ ERROR the trait bound `dyn Trait<A = A, B = B>: Trait` is not satisfied
 }
 
 fn foo<A, B, T: ?Sized>(x: T::A) -> B
diff --git a/tests/ui/traits/new-solver/more-object-bound.stderr b/tests/ui/traits/new-solver/more-object-bound.stderr
index 208fdecb08fc9..4554b8c7473cb 100644
--- a/tests/ui/traits/new-solver/more-object-bound.stderr
+++ b/tests/ui/traits/new-solver/more-object-bound.stderr
@@ -1,10 +1,9 @@
-error[E0283]: type annotations needed: cannot satisfy `dyn Trait<A = A, B = B>: Trait`
-  --> $DIR/more-object-bound.rs:12:5
+error[E0277]: the trait bound `dyn Trait<A = A, B = B>: Trait` is not satisfied
+  --> $DIR/more-object-bound.rs:12:17
    |
 LL |     foo::<A, B, dyn Trait<A = A, B = B>>(x)
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `dyn Trait<A = A, B = B>`
    |
-   = note: cannot satisfy `dyn Trait<A = A, B = B>: Trait`
 note: required by a bound in `foo`
   --> $DIR/more-object-bound.rs:18:8
    |
@@ -13,7 +12,11 @@ LL | fn foo<A, B, T: ?Sized>(x: T::A) -> B
 LL | where
 LL |     T: Trait<B = B>,
    |        ^^^^^^^^^^^^ required by this bound in `foo`
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
+   |
+LL | fn transmute<A, B>(x: A) -> B where dyn Trait<A = A, B = B>: Trait {
+   |                               ++++++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0283`.
+For more information about this error, try `rustc --explain E0277`.