diff --git a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
index e099445117225..c8a63c9c3f8d3 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
@@ -10,7 +10,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{self, subst::SubstsRef, AdtDef, Ty};
 use rustc_span::DUMMY_SP;
 use rustc_trait_selection::traits::{
-    self, FulfillmentContext, ImplSource, Obligation, ObligationCause, SelectionContext,
+    self, ImplSource, Obligation, ObligationCause, SelectionContext, TraitEngineExt,
 };
 
 use super::ConstCx;
@@ -191,7 +191,7 @@ impl Qualif for NeedsNonConstDrop {
 
             // If we successfully found one, then select all of the predicates
             // implied by our const drop impl.
-            let mut fcx = FulfillmentContext::new();
+            let mut fcx = <dyn TraitEngine<'tcx>>::new(cx.tcx);
             for nested in impl_src.nested_obligations() {
                 fcx.register_predicate_obligation(&infcx, nested);
             }
diff --git a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
index 9bdd437333bb6..d0d9efe152cc0 100644
--- a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
+++ b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
@@ -17,7 +17,7 @@ impl<'a, 'tcx> CombineFields<'a, 'tcx> {
     ///
     /// This is implemented by first entering a new universe.
     /// We then replace all bound variables in `sup` with placeholders,
-    /// and all bound variables in `sup` with inference vars.
+    /// and all bound variables in `sub` with inference vars.
     /// We can then just relate the two resulting types as normal.
     ///
     /// Note: this is a subtle algorithm. For a full explanation, please see
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index 5763e6d1b559e..294c81d0b2111 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -205,7 +205,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
             // At this point, we already have all of the bounds we need. FulfillmentContext is used
             // to store all of the necessary region/lifetime bounds in the InferContext, as well as
             // an additional sanity check.
-            let mut fulfill = FulfillmentContext::new();
+            let mut fulfill = <dyn TraitEngine<'tcx>>::new(tcx);
             fulfill.register_bound(&infcx, full_env, ty, trait_did, ObligationCause::dummy());
             let errors = fulfill.select_all_or_error(&infcx);
 
diff --git a/compiler/rustc_trait_selection/src/traits/codegen.rs b/compiler/rustc_trait_selection/src/traits/codegen.rs
index 4b575ea660a79..c0700748c79f9 100644
--- a/compiler/rustc_trait_selection/src/traits/codegen.rs
+++ b/compiler/rustc_trait_selection/src/traits/codegen.rs
@@ -5,7 +5,7 @@
 
 use crate::infer::{DefiningAnchor, TyCtxtInferExt};
 use crate::traits::{
-    FulfillmentContext, ImplSource, Obligation, ObligationCause, SelectionContext, TraitEngine,
+    ImplSource, Obligation, ObligationCause, SelectionContext, TraitEngine, TraitEngineExt,
     Unimplemented,
 };
 use rustc_middle::traits::CodegenObligationError;
@@ -53,7 +53,7 @@ pub fn codegen_fulfill_obligation<'tcx>(
         // Currently, we use a fulfillment context to completely resolve
         // all nested obligations. This is because they can inform the
         // inference of the impl's type parameters.
-        let mut fulfill_cx = FulfillmentContext::new();
+        let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(tcx);
         let impl_source = selection.map(|predicate| {
             fulfill_cx.register_predicate_obligation(&infcx, predicate);
         });
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index f62ccb99df5eb..1c8cdf4ca8fff 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -11,7 +11,7 @@ use crate::traits::util::impl_subject_and_oblig;
 use crate::traits::SkipLeakCheck;
 use crate::traits::{
     self, FulfillmentContext, Normalized, Obligation, ObligationCause, PredicateObligation,
-    PredicateObligations, SelectionContext,
+    PredicateObligations, SelectionContext, TraitEngineExt,
 };
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::Diagnostic;
@@ -385,7 +385,7 @@ fn resolve_negative_obligation<'cx, 'tcx>(
         return false;
     };
 
-    let mut fulfillment_cx = FulfillmentContext::new();
+    let mut fulfillment_cx = <dyn TraitEngine<'tcx>>::new(infcx.tcx);
     fulfillment_cx.register_predicate_obligation(infcx, o);
 
     let errors = fulfillment_cx.select_all_or_error(infcx);
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index d0a17f712d3df..9c6bb0731f441 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -164,7 +164,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'a, 'tcx>(
         // The handling of regions in this area of the code is terrible,
         // see issue #29149. We should be able to improve on this with
         // NLL.
-        let mut fulfill_cx = FulfillmentContext::new();
+        let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(infcx.tcx);
 
         // We can use a dummy node-id here because we won't pay any mind
         // to region obligations that arise (there shouldn't really be any
diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
index 5f77aae6f221f..28a1cb273a72f 100644
--- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
@@ -14,7 +14,9 @@ use specialization_graph::GraphExt;
 
 use crate::infer::{InferCtxt, InferOk, TyCtxtInferExt};
 use crate::traits::select::IntercrateAmbiguityCause;
-use crate::traits::{self, coherence, FutureCompatOverlapErrorKind, ObligationCause, TraitEngine};
+use crate::traits::{
+    self, coherence, FutureCompatOverlapErrorKind, ObligationCause, TraitEngine, TraitEngineExt,
+};
 use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_errors::{struct_span_err, EmissionGuarantee, LintDiagnosticBuilder};
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -24,8 +26,8 @@ use rustc_session::lint::builtin::COHERENCE_LEAK_CHECK;
 use rustc_session::lint::builtin::ORDER_DEPENDENT_TRAIT_OBJECTS;
 use rustc_span::{Span, DUMMY_SP};
 
-use super::util;
-use super::{FulfillmentContext, SelectionContext};
+use super::SelectionContext;
+use super::{util, FulfillmentContext};
 
 /// Information pertinent to an overlapping impl error.
 #[derive(Debug)]
@@ -207,7 +209,7 @@ fn fulfill_implication<'a, 'tcx>(
     // (which are packed up in penv)
 
     infcx.save_and_restore_in_snapshot_flag(|infcx| {
-        let mut fulfill_cx = FulfillmentContext::new();
+        let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(infcx.tcx);
         for oblig in obligations.chain(more_obligations) {
             fulfill_cx.register_predicate_obligation(&infcx, oblig);
         }
diff --git a/compiler/rustc_trait_selection/src/traits/structural_match.rs b/compiler/rustc_trait_selection/src/traits/structural_match.rs
index c278752e3d9f4..5829a0f92ee41 100644
--- a/compiler/rustc_trait_selection/src/traits/structural_match.rs
+++ b/compiler/rustc_trait_selection/src/traits/structural_match.rs
@@ -1,6 +1,6 @@
 use crate::infer::{InferCtxt, TyCtxtInferExt};
 use crate::traits::ObligationCause;
-use crate::traits::{self, TraitEngine};
+use crate::traits::{TraitEngine, TraitEngineExt};
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
@@ -72,7 +72,7 @@ fn type_marked_structural<'tcx>(
     adt_ty: Ty<'tcx>,
     cause: ObligationCause<'tcx>,
 ) -> bool {
-    let mut fulfillment_cx = traits::FulfillmentContext::new();
+    let mut fulfillment_cx = <dyn TraitEngine<'tcx>>::new(infcx.tcx);
     // require `#[derive(PartialEq)]`
     let structural_peq_def_id =
         infcx.tcx.require_lang_item(LangItem::StructuralPeq, Some(cause.span));
diff --git a/compiler/rustc_traits/src/implied_outlives_bounds.rs b/compiler/rustc_traits/src/implied_outlives_bounds.rs
index 4d4d55de5f457..e3e78f70b15ef 100644
--- a/compiler/rustc_traits/src/implied_outlives_bounds.rs
+++ b/compiler/rustc_traits/src/implied_outlives_bounds.rs
@@ -14,8 +14,7 @@ use rustc_span::source_map::DUMMY_SP;
 use rustc_trait_selection::infer::InferCtxtBuilderExt;
 use rustc_trait_selection::traits::query::{CanonicalTyGoal, Fallible, NoSolution};
 use rustc_trait_selection::traits::wf;
-use rustc_trait_selection::traits::FulfillmentContext;
-use rustc_trait_selection::traits::TraitEngine;
+use rustc_trait_selection::traits::{TraitEngine, TraitEngineExt};
 use smallvec::{smallvec, SmallVec};
 
 pub(crate) fn provide(p: &mut Providers) {
@@ -52,7 +51,7 @@ fn compute_implied_outlives_bounds<'tcx>(
 
     let mut implied_bounds = vec![];
 
-    let mut fulfill_cx = FulfillmentContext::new();
+    let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(tcx);
 
     while let Some(arg) = wf_args.pop() {
         if !checked_wf_args.insert(arg) {
diff --git a/compiler/rustc_typeck/src/coherence/builtin.rs b/compiler/rustc_typeck/src/coherence/builtin.rs
index c23cbd71723a0..50946cc1def0c 100644
--- a/compiler/rustc_typeck/src/coherence/builtin.rs
+++ b/compiler/rustc_typeck/src/coherence/builtin.rs
@@ -109,7 +109,7 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
                 // it is not immediately clear why Copy is not implemented for a field, since
                 // all we point at is the field itself.
                 tcx.infer_ctxt().ignoring_regions().enter(|infcx| {
-                    let mut fulfill_cx = traits::FulfillmentContext::new();
+                    let mut fulfill_cx = <dyn TraitEngine<'_>>::new(tcx);
                     fulfill_cx.register_bound(
                         &infcx,
                         param_env,
diff --git a/compiler/rustc_typeck/src/hir_wf_check.rs b/compiler/rustc_typeck/src/hir_wf_check.rs
index 3dc728271b07a..55c7a15f9bcd1 100644
--- a/compiler/rustc_typeck/src/hir_wf_check.rs
+++ b/compiler/rustc_typeck/src/hir_wf_check.rs
@@ -7,7 +7,7 @@ use rustc_infer::traits::TraitEngine;
 use rustc_infer::traits::{ObligationCause, WellFormedLoc};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, Region, ToPredicate, TyCtxt, TypeFoldable, TypeFolder};
-use rustc_trait_selection::traits;
+use rustc_trait_selection::traits::{self, TraitEngineExt};
 
 pub fn provide(providers: &mut Providers) {
     *providers = Providers { diagnostic_hir_wf_check, ..*providers };
@@ -66,7 +66,7 @@ fn diagnostic_hir_wf_check<'tcx>(
     impl<'tcx> Visitor<'tcx> for HirWfCheck<'tcx> {
         fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
             self.tcx.infer_ctxt().enter(|infcx| {
-                let mut fulfill = traits::FulfillmentContext::new();
+                let mut fulfill = <dyn TraitEngine<'tcx>>::new(self.tcx);
                 let tcx_ty =
                     self.icx.to_ty(ty).fold_with(&mut EraseAllBoundRegions { tcx: self.tcx });
                 let cause = traits::ObligationCause::new(
diff --git a/compiler/rustc_typeck/src/outlives/outlives_bounds.rs b/compiler/rustc_typeck/src/outlives/outlives_bounds.rs
index 70b8bcd02208d..229a64650848c 100644
--- a/compiler/rustc_typeck/src/outlives/outlives_bounds.rs
+++ b/compiler/rustc_typeck/src/outlives/outlives_bounds.rs
@@ -3,7 +3,7 @@ use rustc_middle::ty::{self, Ty};
 use rustc_trait_selection::infer::InferCtxt;
 use rustc_trait_selection::traits::query::type_op::{self, TypeOp, TypeOpOutput};
 use rustc_trait_selection::traits::query::NoSolution;
-use rustc_trait_selection::traits::{FulfillmentContext, ObligationCause, TraitEngine};
+use rustc_trait_selection::traits::{ObligationCause, TraitEngine, TraitEngineExt};
 
 pub use rustc_middle::traits::query::OutlivesBound;
 
@@ -63,7 +63,7 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'cx, 'tcx> {
         if let Some(constraints) = constraints {
             // Instantiation may have produced new inference variables and constraints on those
             // variables. Process these constraints.
-            let mut fulfill_cx = FulfillmentContext::new();
+            let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(self.tcx);
             let cause = ObligationCause::misc(span, body_id);
             for &constraint in &constraints.outlives {
                 let obligation = self.query_outlives_constraint_to_obligation(
diff --git a/library/core/src/alloc/global.rs b/library/core/src/alloc/global.rs
index 887246c600144..6756eecd0e0f8 100644
--- a/library/core/src/alloc/global.rs
+++ b/library/core/src/alloc/global.rs
@@ -74,7 +74,7 @@ use crate::ptr;
 ///         {
 ///             return null_mut();
 ///         };
-///         (self.arena.get() as *mut u8).add(allocated)
+///         self.arena.get().cast::<u8>().add(allocated)
 ///     }
 ///     unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
 /// }
diff --git a/library/core/src/ptr/const_ptr.rs b/library/core/src/ptr/const_ptr.rs
index e0655d68d2cfa..716f7c6af8f34 100644
--- a/library/core/src/ptr/const_ptr.rs
+++ b/library/core/src/ptr/const_ptr.rs
@@ -1267,20 +1267,21 @@ impl<T: ?Sized> *const T {
     /// Accessing adjacent `u8` as `u16`
     ///
     /// ```
-    /// # fn foo(n: usize) {
-    /// # use std::mem::align_of;
+    /// use std::mem::align_of;
+    ///
     /// # unsafe {
-    /// let x = [5u8, 6u8, 7u8, 8u8, 9u8];
-    /// let ptr = x.as_ptr().add(n) as *const u8;
+    /// let x = [5_u8, 6, 7, 8, 9];
+    /// let ptr = x.as_ptr();
     /// let offset = ptr.align_offset(align_of::<u16>());
-    /// if offset < x.len() - n - 1 {
-    ///     let u16_ptr = ptr.add(offset) as *const u16;
-    ///     assert_ne!(*u16_ptr, 500);
+    ///
+    /// if offset < x.len() - 1 {
+    ///     let u16_ptr = ptr.add(offset).cast::<u16>();
+    ///     assert!(*u16_ptr == u16::from_ne_bytes([5, 6]) || *u16_ptr == u16::from_ne_bytes([6, 7]));
     /// } else {
     ///     // while the pointer can be aligned via `offset`, it would point
     ///     // outside the allocation
     /// }
-    /// # } }
+    /// # }
     /// ```
     #[stable(feature = "align_offset", since = "1.36.0")]
     #[rustc_const_unstable(feature = "const_align_offset", issue = "90962")]
diff --git a/library/core/src/ptr/mut_ptr.rs b/library/core/src/ptr/mut_ptr.rs
index fc3dd2a9b25a9..b8551eeed9e0d 100644
--- a/library/core/src/ptr/mut_ptr.rs
+++ b/library/core/src/ptr/mut_ptr.rs
@@ -1545,20 +1545,23 @@ impl<T: ?Sized> *mut T {
     /// Accessing adjacent `u8` as `u16`
     ///
     /// ```
-    /// # fn foo(n: usize) {
-    /// # use std::mem::align_of;
+    /// use std::mem::align_of;
+    ///
     /// # unsafe {
-    /// let x = [5u8, 6u8, 7u8, 8u8, 9u8];
-    /// let ptr = x.as_ptr().add(n) as *const u8;
+    /// let mut x = [5_u8, 6, 7, 8, 9];
+    /// let ptr = x.as_mut_ptr();
     /// let offset = ptr.align_offset(align_of::<u16>());
-    /// if offset < x.len() - n - 1 {
-    ///     let u16_ptr = ptr.add(offset) as *const u16;
-    ///     assert_ne!(*u16_ptr, 500);
+    ///
+    /// if offset < x.len() - 1 {
+    ///     let u16_ptr = ptr.add(offset).cast::<u16>();
+    ///     *u16_ptr = 0;
     /// } else {
     ///     // while the pointer can be aligned via `offset`, it would point
     ///     // outside the allocation
     /// }
-    /// # } }
+    ///
+    /// assert!(x == [0, 0, 7, 8, 9] || x == [5, 0, 0, 8, 9]);
+    /// # }
     /// ```
     #[stable(feature = "align_offset", since = "1.36.0")]
     #[rustc_const_unstable(feature = "const_align_offset", issue = "90962")]
diff --git a/library/core/src/slice/iter.rs b/library/core/src/slice/iter.rs
index 76b4a534e5db5..c310ffe091d2c 100644
--- a/library/core/src/slice/iter.rs
+++ b/library/core/src/slice/iter.rs
@@ -92,7 +92,7 @@ impl<'a, T> Iter<'a, T> {
             assume(!ptr.is_null());
 
             let end = if mem::size_of::<T>() == 0 {
-                (ptr as *const u8).wrapping_add(slice.len()) as *const T
+                ptr.wrapping_byte_add(slice.len())
             } else {
                 ptr.add(slice.len())
             };
@@ -228,7 +228,7 @@ impl<'a, T> IterMut<'a, T> {
             assume(!ptr.is_null());
 
             let end = if mem::size_of::<T>() == 0 {
-                (ptr as *mut u8).wrapping_add(slice.len()) as *mut T
+                ptr.wrapping_byte_add(slice.len())
             } else {
                 ptr.add(slice.len())
             };
diff --git a/library/core/tests/const_ptr.rs b/library/core/tests/const_ptr.rs
index 152fed803ecdb..d874f08317f61 100644
--- a/library/core/tests/const_ptr.rs
+++ b/library/core/tests/const_ptr.rs
@@ -3,7 +3,7 @@ const DATA: [u16; 2] = [u16::from_ne_bytes([0x01, 0x23]), u16::from_ne_bytes([0x
 
 const fn unaligned_ptr() -> *const u16 {
     // Since DATA.as_ptr() is aligned to two bytes, adding 1 byte to that produces an unaligned *const u16
-    unsafe { (DATA.as_ptr() as *const u8).add(1) as *const u16 }
+    unsafe { DATA.as_ptr().byte_add(1) }
 }
 
 #[test]
@@ -67,7 +67,7 @@ fn write() {
     const fn write_unaligned() -> [u16; 2] {
         let mut two_aligned = [0u16; 2];
         unsafe {
-            let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16;
+            let unaligned_ptr = two_aligned.as_mut_ptr().byte_add(1);
             ptr::write_unaligned(unaligned_ptr, u16::from_ne_bytes([0x23, 0x45]));
         }
         two_aligned
@@ -91,7 +91,7 @@ fn mut_ptr_write() {
     const fn write_unaligned() -> [u16; 2] {
         let mut two_aligned = [0u16; 2];
         unsafe {
-            let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16;
+            let unaligned_ptr = two_aligned.as_mut_ptr().byte_add(1);
             unaligned_ptr.write_unaligned(u16::from_ne_bytes([0x23, 0x45]));
         }
         two_aligned
diff --git a/library/core/tests/lib.rs b/library/core/tests/lib.rs
index db94368f6e0cc..df9b1073a0994 100644
--- a/library/core/tests/lib.rs
+++ b/library/core/tests/lib.rs
@@ -14,6 +14,7 @@
 #![feature(const_maybe_uninit_assume_init_read)]
 #![feature(const_nonnull_new)]
 #![feature(const_num_from_num)]
+#![feature(const_pointer_byte_offsets)]
 #![feature(const_ptr_as_ref)]
 #![feature(const_ptr_read)]
 #![feature(const_ptr_write)]
@@ -74,6 +75,7 @@
 #![feature(never_type)]
 #![feature(unwrap_infallible)]
 #![feature(result_into_ok_or_err)]
+#![feature(pointer_byte_offsets)]
 #![feature(portable_simd)]
 #![feature(ptr_metadata)]
 #![feature(once_cell)]
diff --git a/library/std/src/sys/sgx/abi/usercalls/alloc.rs b/library/std/src/sys/sgx/abi/usercalls/alloc.rs
index ea24fedd0eb3d..22cbbcf689abd 100644
--- a/library/std/src/sys/sgx/abi/usercalls/alloc.rs
+++ b/library/std/src/sys/sgx/abi/usercalls/alloc.rs
@@ -115,7 +115,7 @@ pub unsafe trait UserSafe {
     /// * the pointer is null.
     /// * the pointed-to range is not in user memory.
     unsafe fn check_ptr(ptr: *const Self) {
-        let is_aligned = |p| -> bool { 0 == (p as usize) & (Self::align_of() - 1) };
+        let is_aligned = |p| -> bool { 0 == p.addr() & (Self::align_of() - 1) };
 
         assert!(is_aligned(ptr as *const u8));
         assert!(is_user_range(ptr as _, mem::size_of_val(unsafe { &*ptr })));
diff --git a/library/std/src/sys/unsupported/alloc.rs b/library/std/src/sys/unsupported/alloc.rs
index 8d5d0a2f5ccd1..d715ae45401e6 100644
--- a/library/std/src/sys/unsupported/alloc.rs
+++ b/library/std/src/sys/unsupported/alloc.rs
@@ -1,15 +1,16 @@
 use crate::alloc::{GlobalAlloc, Layout, System};
+use crate::ptr::null_mut;
 
 #[stable(feature = "alloc_system_type", since = "1.28.0")]
 unsafe impl GlobalAlloc for System {
     #[inline]
     unsafe fn alloc(&self, _layout: Layout) -> *mut u8 {
-        0 as *mut u8
+        null_mut()
     }
 
     #[inline]
     unsafe fn alloc_zeroed(&self, _layout: Layout) -> *mut u8 {
-        0 as *mut u8
+        null_mut()
     }
 
     #[inline]
@@ -17,6 +18,6 @@ unsafe impl GlobalAlloc for System {
 
     #[inline]
     unsafe fn realloc(&self, _ptr: *mut u8, _layout: Layout, _new_size: usize) -> *mut u8 {
-        0 as *mut u8
+        null_mut()
     }
 }
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index 3347246ea8f6f..4d548dbb63875 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -345,13 +345,6 @@ impl Step for Llvm {
             cfg.define("LLVM_ENABLE_ZLIB", "OFF");
         }
 
-        if builder.config.llvm_thin_lto {
-            cfg.define("LLVM_ENABLE_LTO", "Thin");
-            if !target.contains("apple") {
-                cfg.define("LLVM_ENABLE_LLD", "ON");
-            }
-        }
-
         // This setting makes the LLVM tools link to the dynamic LLVM library,
         // which saves both memory during parallel links and overall disk space
         // for the tools. We don't do this on every platform as it doesn't work
@@ -463,15 +456,8 @@ impl Step for Llvm {
             cfg.define("LLVM_VERSION_SUFFIX", suffix);
         }
 
-        if let Some(ref linker) = builder.config.llvm_use_linker {
-            cfg.define("LLVM_USE_LINKER", linker);
-        }
-
-        if builder.config.llvm_allow_old_toolchain {
-            cfg.define("LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN", "YES");
-        }
-
         configure_cmake(builder, target, &mut cfg, true, ldflags);
+        configure_llvm(builder, target, &mut cfg);
 
         for (key, val) in &builder.config.llvm_build_config {
             cfg.define(key, val);
@@ -731,6 +717,25 @@ fn configure_cmake(
     }
 }
 
+fn configure_llvm(builder: &Builder<'_>, target: TargetSelection, cfg: &mut cmake::Config) {
+    // ThinLTO is only available when building with LLVM, enabling LLD is required.
+    // Apple's linker ld64 supports ThinLTO out of the box though, so don't use LLD on Darwin.
+    if builder.config.llvm_thin_lto {
+        cfg.define("LLVM_ENABLE_LTO", "Thin");
+        if !target.contains("apple") {
+            cfg.define("LLVM_ENABLE_LLD", "ON");
+        }
+    }
+
+    if let Some(ref linker) = builder.config.llvm_use_linker {
+        cfg.define("LLVM_USE_LINKER", linker);
+    }
+
+    if builder.config.llvm_allow_old_toolchain {
+        cfg.define("LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN", "YES");
+    }
+}
+
 // Adapted from https://github.com/alexcrichton/cc-rs/blob/fba7feded71ee4f63cfe885673ead6d7b4f2f454/src/lib.rs#L2347-L2365
 fn get_var(var_base: &str, host: &str, target: &str) -> Option<OsString> {
     let kind = if host == target { "HOST" } else { "TARGET" };
@@ -794,6 +799,7 @@ impl Step for Lld {
         }
 
         configure_cmake(builder, target, &mut cfg, true, ldflags);
+        configure_llvm(builder, target, &mut cfg);
 
         // This is an awful, awful hack. Discovered when we migrated to using
         // clang-cl to compile LLVM/LLD it turns out that LLD, when built out of
@@ -825,10 +831,6 @@ impl Step for Lld {
             .define("LLVM_CONFIG_PATH", llvm_config_shim)
             .define("LLVM_INCLUDE_TESTS", "OFF");
 
-        if builder.config.llvm_allow_old_toolchain {
-            cfg.define("LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN", "YES");
-        }
-
         // While we're using this horrible workaround to shim the execution of
         // llvm-config, let's just pile on more. I can't seem to figure out how
         // to build LLD as a standalone project and also cross-compile it at the
diff --git a/src/librustdoc/html/render/write_shared.rs b/src/librustdoc/html/render/write_shared.rs
index 27ad91d09e064..6fb41ff327916 100644
--- a/src/librustdoc/html/render/write_shared.rs
+++ b/src/librustdoc/html/render/write_shared.rs
@@ -366,13 +366,15 @@ pub(super) fn write_shared(
                 .collect::<Vec<_>>();
             files.sort_unstable();
             let subs = subs.iter().map(|s| s.to_json_string()).collect::<Vec<_>>().join(",");
-            let dirs =
-                if subs.is_empty() { String::new() } else { format!(",\"dirs\":[{}]", subs) };
+            let dirs = if subs.is_empty() && files.is_empty() {
+                String::new()
+            } else {
+                format!(",[{}]", subs)
+            };
             let files = files.join(",");
-            let files =
-                if files.is_empty() { String::new() } else { format!(",\"files\":[{}]", files) };
+            let files = if files.is_empty() { String::new() } else { format!(",[{}]", files) };
             format!(
-                "{{\"name\":\"{name}\"{dirs}{files}}}",
+                "[\"{name}\"{dirs}{files}]",
                 name = self.elem.to_str().expect("invalid osstring conversion"),
                 dirs = dirs,
                 files = files
@@ -411,18 +413,23 @@ pub(super) fn write_shared(
         let dst = cx.dst.join(&format!("source-files{}.js", cx.shared.resource_suffix));
         let make_sources = || {
             let (mut all_sources, _krates) =
-                try_err!(collect(&dst, krate.name(cx.tcx()).as_str(), "sourcesIndex"), &dst);
+                try_err!(collect_json(&dst, krate.name(cx.tcx()).as_str()), &dst);
             all_sources.push(format!(
-                "sourcesIndex[\"{}\"] = {};",
+                r#""{}":{}"#,
                 &krate.name(cx.tcx()),
-                hierarchy.to_json_string()
+                hierarchy
+                    .to_json_string()
+                    // All these `replace` calls are because we have to go through JS string for JSON content.
+                    .replace('\\', r"\\")
+                    .replace('\'', r"\'")
+                    // We need to escape double quotes for the JSON.
+                    .replace("\\\"", "\\\\\"")
             ));
             all_sources.sort();
-            Ok(format!(
-                "var sourcesIndex = {{}};\n{}\ncreateSourceSidebar();\n",
-                all_sources.join("\n")
-            )
-            .into_bytes())
+            let mut v = String::from("var sourcesIndex = JSON.parse('{\\\n");
+            v.push_str(&all_sources.join(",\\\n"));
+            v.push_str("\\\n}');\ncreateSourceSidebar();\n");
+            Ok(v.into_bytes())
         };
         write_crate("source-files.js", &make_sources)?;
     }
diff --git a/src/librustdoc/html/static/js/source-script.js b/src/librustdoc/html/static/js/source-script.js
index a6a0b09ef31fe..c45d614293a85 100644
--- a/src/librustdoc/html/static/js/source-script.js
+++ b/src/librustdoc/html/static/js/source-script.js
@@ -12,6 +12,10 @@
 const rootPath = document.getElementById("rustdoc-vars").attributes["data-root-path"].value;
 let oldScrollPosition = 0;
 
+const NAME_OFFSET = 0;
+const DIRS_OFFSET = 1;
+const FILES_OFFSET = 2;
+
 function closeSidebarIfMobile() {
     if (window.innerWidth < window.RUSTDOC_MOBILE_BREAKPOINT) {
         updateLocalStorage("source-sidebar-show", "false");
@@ -24,15 +28,15 @@ function createDirEntry(elem, parent, fullPath, hasFoundFile) {
 
     dirEntry.className = "dir-entry";
 
-    fullPath += elem["name"] + "/";
+    fullPath += elem[NAME_OFFSET] + "/";
 
-    summary.innerText = elem["name"];
+    summary.innerText = elem[NAME_OFFSET];
     dirEntry.appendChild(summary);
 
     const folders = document.createElement("div");
     folders.className = "folders";
-    if (elem.dirs) {
-        for (const dir of elem.dirs) {
+    if (elem[DIRS_OFFSET]) {
+        for (const dir of elem[DIRS_OFFSET]) {
             if (createDirEntry(dir, folders, fullPath, false)) {
                 dirEntry.open = true;
                 hasFoundFile = true;
@@ -43,8 +47,8 @@ function createDirEntry(elem, parent, fullPath, hasFoundFile) {
 
     const files = document.createElement("div");
     files.className = "files";
-    if (elem.files) {
-        for (const file_text of elem.files) {
+    if (elem[FILES_OFFSET]) {
+        for (const file_text of elem[FILES_OFFSET]) {
             const file = document.createElement("a");
             file.innerText = file_text;
             file.href = rootPath + "src/" + fullPath + file_text + ".html";
@@ -125,7 +129,7 @@ function createSourceSidebar() {
     title.innerText = "Files";
     sidebar.appendChild(title);
     Object.keys(sourcesIndex).forEach(key => {
-        sourcesIndex[key].name = key;
+        sourcesIndex[key][NAME_OFFSET] = key;
         hasFoundFile = createDirEntry(sourcesIndex[key], sidebar, "",
             hasFoundFile);
     });