diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index dacd8f7c12cfd..550715abc10bf 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -423,14 +423,14 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
     }
 
     #[inline(always)]
-    fn stack(
+    fn stack<'a>(
         ecx: &'a InterpCx<'mir, 'tcx, Self>,
     ) -> &'a [Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>] {
         &ecx.machine.stack
     }
 
     #[inline(always)]
-    fn stack_mut(
+    fn stack_mut<'a>(
         ecx: &'a mut InterpCx<'mir, 'tcx, Self>,
     ) -> &'a mut Vec<Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>> {
         &mut ecx.machine.stack
diff --git a/compiler/rustc_const_eval/src/const_eval/mod.rs b/compiler/rustc_const_eval/src/const_eval/mod.rs
index a334165df4cb1..91b17d1ac1ef8 100644
--- a/compiler/rustc_const_eval/src/const_eval/mod.rs
+++ b/compiler/rustc_const_eval/src/const_eval/mod.rs
@@ -25,9 +25,9 @@ pub use fn_queries::*;
 pub use machine::*;
 
 pub(crate) fn const_caller_location(
-    tcx: TyCtxt<'tcx>,
+    tcx: TyCtxt<'_>,
     (file, line, col): (Symbol, u32, u32),
-) -> ConstValue<'tcx> {
+) -> ConstValue<'_> {
     trace!("const_caller_location: {}:{}:{}", file, line, col);
     let mut ecx = mk_eval_cx(tcx, DUMMY_SP, ty::ParamEnv::reveal_all(), false);
 
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index 67351aa3653f3..d768f06c4f00d 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -935,7 +935,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     }
 
     #[must_use]
-    pub fn dump_place(&'a self, place: Place<M::PointerTag>) -> PlacePrinter<'a, 'mir, 'tcx, M> {
+    pub fn dump_place(&self, place: Place<M::PointerTag>) -> PlacePrinter<'_, 'mir, 'tcx, M> {
         PlacePrinter { ecx: self, place }
     }
 
diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs
index 84e79408397e5..a1dd587c17ab5 100644
--- a/compiler/rustc_const_eval/src/interpret/intern.rs
+++ b/compiler/rustc_const_eval/src/interpret/intern.rs
@@ -292,14 +292,15 @@ pub enum InternKind {
 /// Any errors here would anyway be turned into `const_err` lints, whereas validation failures
 /// are hard errors.
 #[tracing::instrument(level = "debug", skip(ecx))]
-pub fn intern_const_alloc_recursive<M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>>(
+pub fn intern_const_alloc_recursive<
+    'mir,
+    'tcx: 'mir,
+    M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>,
+>(
     ecx: &mut InterpCx<'mir, 'tcx, M>,
     intern_kind: InternKind,
     ret: &MPlaceTy<'tcx>,
-) -> Result<(), ErrorReported>
-where
-    'tcx: 'mir,
-{
+) -> Result<(), ErrorReported> {
     let tcx = ecx.tcx;
     let base_intern_mode = match intern_kind {
         InternKind::Static(mutbl) => InternMode::Static(mutbl),
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
index 5b4a5ac357722..b77c1c71a15d6 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
@@ -148,7 +148,7 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
     }
 }
 
-impl PrettyPrinter<'tcx> for AbsolutePathPrinter<'tcx> {
+impl<'tcx> PrettyPrinter<'tcx> for AbsolutePathPrinter<'tcx> {
     fn region_should_not_be_omitted(&self, _region: ty::Region<'_>) -> bool {
         false
     }
diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs
index 51207828935d2..727099848a4ff 100644
--- a/compiler/rustc_const_eval/src/interpret/machine.rs
+++ b/compiler/rustc_const_eval/src/interpret/machine.rs
@@ -374,12 +374,12 @@ pub trait Machine<'mir, 'tcx>: Sized {
     ) -> InterpResult<'tcx, Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>>;
 
     /// Borrow the current thread's stack.
-    fn stack(
+    fn stack<'a>(
         ecx: &'a InterpCx<'mir, 'tcx, Self>,
     ) -> &'a [Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>];
 
     /// Mutably borrow the current thread's stack.
-    fn stack_mut(
+    fn stack_mut<'a>(
         ecx: &'a mut InterpCx<'mir, 'tcx, Self>,
     ) -> &'a mut Vec<Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>>;
 
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index e82ce73c814ff..dfec4509685f6 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -106,7 +106,7 @@ pub struct ImmTy<'tcx, Tag: Provenance = AllocId> {
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 rustc_data_structures::static_assert_size!(ImmTy<'_>, 72);
 
-impl<Tag: Provenance> std::fmt::Display for ImmTy<'tcx, Tag> {
+impl<Tag: Provenance> std::fmt::Display for ImmTy<'_, Tag> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         /// Helper function for printing a scalar to a FmtPrinter
         fn p<'a, 'tcx, F: std::fmt::Write, Tag: Provenance>(
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index e526bfa2b52c7..851c2a6bb2e39 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -150,7 +150,7 @@ impl<Tag: Provenance> MemPlace<Tag> {
     }
 
     #[inline]
-    pub fn offset(
+    pub fn offset<'tcx>(
         self,
         offset: Size,
         meta: MemPlaceMeta<Tag>,
@@ -420,7 +420,7 @@ where
 
     // Iterates over all fields of an array. Much more efficient than doing the
     // same by repeatedly calling `mplace_array`.
-    pub(super) fn mplace_array_fields(
+    pub(super) fn mplace_array_fields<'a>(
         &self,
         base: &'a MPlaceTy<'tcx, Tag>,
     ) -> InterpResult<'tcx, impl Iterator<Item = InterpResult<'tcx, MPlaceTy<'tcx, Tag>>> + 'a>
diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs
index f308e764e861d..bb0ecdd928100 100644
--- a/compiler/rustc_const_eval/src/lib.rs
+++ b/compiler/rustc_const_eval/src/lib.rs
@@ -11,7 +11,6 @@ Rust MIR: a lowered representation of Rust.
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(exact_size_is_empty)]
-#![feature(in_band_lifetimes)]
 #![feature(iter_zip)]
 #![feature(let_else)]
 #![feature(map_try_insert)]
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
index 5a4aa06f3bbae..1d5f463015294 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
@@ -35,7 +35,7 @@ pub struct Qualifs<'mir, 'tcx> {
     needs_non_const_drop: Option<QualifResults<'mir, 'tcx, NeedsNonConstDrop>>,
 }
 
-impl Qualifs<'mir, 'tcx> {
+impl<'mir, 'tcx> Qualifs<'mir, 'tcx> {
     /// Returns `true` if `local` is `NeedsDrop` at the given `Location`.
     ///
     /// Only updates the cursor if absolutely necessary
@@ -185,7 +185,7 @@ pub struct Checker<'mir, 'tcx> {
     secondary_errors: Vec<Diagnostic>,
 }
 
-impl Deref for Checker<'mir, 'tcx> {
+impl<'mir, 'tcx> Deref for Checker<'mir, 'tcx> {
     type Target = ConstCx<'mir, 'tcx>;
 
     fn deref(&self) -> &Self::Target {
@@ -193,7 +193,7 @@ impl Deref for Checker<'mir, 'tcx> {
     }
 }
 
-impl Checker<'mir, 'tcx> {
+impl<'mir, 'tcx> Checker<'mir, 'tcx> {
     pub fn new(ccx: &'mir ConstCx<'mir, 'tcx>) -> Self {
         Checker {
             span: ccx.body.span,
@@ -273,7 +273,7 @@ impl Checker<'mir, 'tcx> {
                 struct StorageDeads {
                     locals: BitSet<Local>,
                 }
-                impl Visitor<'tcx> for StorageDeads {
+                impl<'tcx> Visitor<'tcx> for StorageDeads {
                     fn visit_statement(&mut self, stmt: &Statement<'tcx>, _: Location) {
                         if let StatementKind::StorageDead(l) = stmt.kind {
                             self.locals.insert(l);
@@ -460,7 +460,7 @@ impl Checker<'mir, 'tcx> {
     }
 }
 
-impl Visitor<'tcx> for Checker<'mir, 'tcx> {
+impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
     fn visit_basic_block_data(&mut self, bb: BasicBlock, block: &BasicBlockData<'tcx>) {
         trace!("visit_basic_block_data: bb={:?} is_cleanup={:?}", bb, block.is_cleanup);
 
@@ -1042,7 +1042,7 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> {
     }
 }
 
-fn place_as_reborrow(
+fn place_as_reborrow<'tcx>(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,
     place: Place<'tcx>,
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/mod.rs b/compiler/rustc_const_eval/src/transform/check_consts/mod.rs
index dc44409d500a0..b026bb2bad657 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/mod.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/mod.rs
@@ -28,7 +28,7 @@ pub struct ConstCx<'mir, 'tcx> {
     pub const_kind: Option<hir::ConstContext>,
 }
 
-impl ConstCx<'mir, 'tcx> {
+impl<'mir, 'tcx> ConstCx<'mir, 'tcx> {
     pub fn new(tcx: TyCtxt<'tcx>, body: &'mir mir::Body<'tcx>) -> Self {
         let def_id = body.source.def_id().expect_local();
         let param_env = tcx.param_env(def_id);
@@ -72,11 +72,7 @@ impl ConstCx<'mir, 'tcx> {
     }
 }
 
-pub fn rustc_allow_const_fn_unstable(
-    tcx: TyCtxt<'tcx>,
-    def_id: DefId,
-    feature_gate: Symbol,
-) -> bool {
+pub fn rustc_allow_const_fn_unstable(tcx: TyCtxt<'_>, def_id: DefId, feature_gate: Symbol) -> bool {
     let attrs = tcx.get_attrs(def_id);
     attr::rustc_allow_const_fn_unstable(&tcx.sess, attrs).any(|name| name == feature_gate)
 }
@@ -89,7 +85,7 @@ pub fn rustc_allow_const_fn_unstable(
 // functions can be called in a const-context by users of the stable compiler. "const-stable"
 // functions are subject to more stringent restrictions than "const-unstable" functions: They
 // cannot use unstable features and can only call other "const-stable" functions.
-pub fn is_const_stable_const_fn(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool {
+pub fn is_const_stable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     use attr::{ConstStability, Stability, StabilityLevel};
 
     // A default body marked const is not const-stable because const
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
index 421c559474a97..24c4a4915e5e8 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
@@ -39,7 +39,7 @@ pub trait NonConstOp: std::fmt::Debug {
         DiagnosticImportance::Primary
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx>;
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx>;
 }
 
 #[derive(Debug)]
@@ -53,7 +53,7 @@ impl NonConstOp for FloatingPointOp {
         }
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         feature_err(
             &ccx.tcx.sess.parse_sess,
             sym::const_fn_floating_point_arithmetic,
@@ -67,7 +67,7 @@ impl NonConstOp for FloatingPointOp {
 #[derive(Debug)]
 pub struct FnCallIndirect;
 impl NonConstOp for FnCallIndirect {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.struct_span_err(span, "function pointers are not allowed in const fn")
     }
 }
@@ -76,7 +76,7 @@ impl NonConstOp for FnCallIndirect {
 #[derive(Debug)]
 pub struct FnCallNonConst<'tcx>(pub Option<(DefId, SubstsRef<'tcx>)>);
 impl<'a> NonConstOp for FnCallNonConst<'a> {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             ccx.tcx.sess,
             span,
@@ -149,7 +149,7 @@ impl<'a> NonConstOp for FnCallNonConst<'a> {
 pub struct FnCallUnstable(pub DefId, pub Option<Symbol>);
 
 impl NonConstOp for FnCallUnstable {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let FnCallUnstable(def_id, feature) = *self;
 
         let mut err = ccx.tcx.sess.struct_span_err(
@@ -183,7 +183,7 @@ impl NonConstOp for FnPtrCast {
         }
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         feature_err(
             &ccx.tcx.sess.parse_sess,
             sym::const_fn_fn_ptr_basics,
@@ -204,7 +204,7 @@ impl NonConstOp for Generator {
         }
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let msg = format!("{}s are not allowed in {}s", self.0, ccx.const_kind());
         if let hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Block) = self.0 {
             feature_err(&ccx.tcx.sess.parse_sess, sym::const_async_blocks, span, &msg)
@@ -217,7 +217,7 @@ impl NonConstOp for Generator {
 #[derive(Debug)]
 pub struct HeapAllocation;
 impl NonConstOp for HeapAllocation {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             ccx.tcx.sess,
             span,
@@ -241,7 +241,7 @@ impl NonConstOp for HeapAllocation {
 #[derive(Debug)]
 pub struct InlineAsm;
 impl NonConstOp for InlineAsm {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(
             ccx.tcx.sess,
             span,
@@ -257,7 +257,7 @@ pub struct LiveDrop {
     pub dropped_at: Option<Span>,
 }
 impl NonConstOp for LiveDrop {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             ccx.tcx.sess,
             span,
@@ -285,7 +285,7 @@ impl NonConstOp for TransientCellBorrow {
         // not additionally emit a feature gate error if activating the feature gate won't work.
         DiagnosticImportance::Secondary
     }
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         feature_err(
             &ccx.tcx.sess.parse_sess,
             sym::const_refs_to_cell,
@@ -301,7 +301,7 @@ impl NonConstOp for TransientCellBorrow {
 /// it in the future for static items.
 pub struct CellBorrow;
 impl NonConstOp for CellBorrow {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             ccx.tcx.sess,
             span,
@@ -348,7 +348,7 @@ impl NonConstOp for MutBorrow {
         DiagnosticImportance::Secondary
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let raw = match self.0 {
             hir::BorrowKind::Raw => "raw ",
             hir::BorrowKind::Ref => "",
@@ -387,7 +387,7 @@ impl NonConstOp for TransientMutBorrow {
         Status::Unstable(sym::const_mut_refs)
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let raw = match self.0 {
             hir::BorrowKind::Raw => "raw ",
             hir::BorrowKind::Ref => "",
@@ -414,7 +414,7 @@ impl NonConstOp for MutDeref {
         DiagnosticImportance::Secondary
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         feature_err(
             &ccx.tcx.sess.parse_sess,
             sym::const_mut_refs,
@@ -428,7 +428,7 @@ impl NonConstOp for MutDeref {
 #[derive(Debug)]
 pub struct PanicNonStr;
 impl NonConstOp for PanicNonStr {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.struct_span_err(
             span,
             "argument to `panic!()` in a const context must have type `&str`",
@@ -442,7 +442,7 @@ impl NonConstOp for PanicNonStr {
 #[derive(Debug)]
 pub struct RawPtrComparison;
 impl NonConstOp for RawPtrComparison {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let mut err = ccx
             .tcx
             .sess
@@ -462,7 +462,7 @@ impl NonConstOp for RawMutPtrDeref {
         Status::Unstable(sym::const_mut_refs)
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         feature_err(
             &ccx.tcx.sess.parse_sess,
             sym::const_mut_refs,
@@ -478,7 +478,7 @@ impl NonConstOp for RawMutPtrDeref {
 #[derive(Debug)]
 pub struct RawPtrToIntCast;
 impl NonConstOp for RawPtrToIntCast {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let mut err = ccx
             .tcx
             .sess
@@ -503,7 +503,7 @@ impl NonConstOp for StaticAccess {
         }
     }
 
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             ccx.tcx.sess,
             span,
@@ -529,7 +529,7 @@ impl NonConstOp for StaticAccess {
 #[derive(Debug)]
 pub struct ThreadLocalAccess;
 impl NonConstOp for ThreadLocalAccess {
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+    fn build_error<'tcx>(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(
             ccx.tcx.sess,
             span,
@@ -560,7 +560,11 @@ pub mod ty {
             }
         }
 
-        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+        fn build_error<'tcx>(
+            &self,
+            ccx: &ConstCx<'_, 'tcx>,
+            span: Span,
+        ) -> DiagnosticBuilder<'tcx> {
             feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_mut_refs,
@@ -590,7 +594,11 @@ pub mod ty {
             }
         }
 
-        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+        fn build_error<'tcx>(
+            &self,
+            ccx: &ConstCx<'_, 'tcx>,
+            span: Span,
+        ) -> DiagnosticBuilder<'tcx> {
             feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_fn_fn_ptr_basics,
@@ -607,7 +615,11 @@ pub mod ty {
             Status::Unstable(sym::const_impl_trait)
         }
 
-        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+        fn build_error<'tcx>(
+            &self,
+            ccx: &ConstCx<'_, 'tcx>,
+            span: Span,
+        ) -> DiagnosticBuilder<'tcx> {
             feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_impl_trait,
@@ -637,7 +649,11 @@ pub mod ty {
             }
         }
 
-        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+        fn build_error<'tcx>(
+            &self,
+            ccx: &ConstCx<'_, 'tcx>,
+            span: Span,
+        ) -> DiagnosticBuilder<'tcx> {
             let mut err = feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_fn_trait_bound,
@@ -676,7 +692,11 @@ pub mod ty {
             }
         }
 
-        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+        fn build_error<'tcx>(
+            &self,
+            ccx: &ConstCx<'_, 'tcx>,
+            span: Span,
+        ) -> DiagnosticBuilder<'tcx> {
             let mut err = feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_fn_trait_bound,
@@ -703,7 +723,11 @@ pub mod ty {
             Status::Unstable(sym::const_trait_bound_opt_out)
         }
 
-        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
+        fn build_error<'tcx>(
+            &self,
+            ccx: &ConstCx<'_, 'tcx>,
+            span: Span,
+        ) -> DiagnosticBuilder<'tcx> {
             feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_trait_bound_opt_out,
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs b/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs
index c1d47baa40531..4e210f66353f3 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs
@@ -23,7 +23,7 @@ pub fn checking_enabled(ccx: &ConstCx<'_, '_>) -> bool {
 ///
 /// This is separate from the rest of the const checking logic because it must run after drop
 /// elaboration.
-pub fn check_live_drops(tcx: TyCtxt<'tcx>, body: &mir::Body<'tcx>) {
+pub fn check_live_drops<'tcx>(tcx: TyCtxt<'tcx>, body: &mir::Body<'tcx>) {
     let def_id = body.source.def_id().expect_local();
     let const_kind = tcx.hir().body_const_context(def_id);
     if const_kind.is_none() {
@@ -50,7 +50,7 @@ struct CheckLiveDrops<'mir, 'tcx> {
 }
 
 // So we can access `body` and `tcx`.
-impl std::ops::Deref for CheckLiveDrops<'mir, 'tcx> {
+impl<'mir, 'tcx> std::ops::Deref for CheckLiveDrops<'mir, 'tcx> {
     type Target = ConstCx<'mir, 'tcx>;
 
     fn deref(&self) -> &Self::Target {
@@ -58,13 +58,13 @@ impl std::ops::Deref for CheckLiveDrops<'mir, 'tcx> {
     }
 }
 
-impl CheckLiveDrops<'mir, 'tcx> {
+impl CheckLiveDrops<'_, '_> {
     fn check_live_drop(&self, span: Span) {
         ops::LiveDrop { dropped_at: None }.build_error(self.ccx, span).emit();
     }
 }
 
-impl Visitor<'tcx> for CheckLiveDrops<'mir, 'tcx> {
+impl<'tcx> Visitor<'tcx> for CheckLiveDrops<'_, 'tcx> {
     fn visit_basic_block_data(&mut self, bb: BasicBlock, block: &mir::BasicBlockData<'tcx>) {
         trace!("visit_basic_block_data: bb={:?} is_cleanup={:?}", bb, block.is_cleanup);
 
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 43612292f5283..a8077b258bb75 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
@@ -13,7 +13,7 @@ use rustc_trait_selection::traits::{
 
 use super::ConstCx;
 
-pub fn in_any_value_of_ty(
+pub fn in_any_value_of_ty<'tcx>(
     cx: &ConstCx<'_, 'tcx>,
     ty: Ty<'tcx>,
     error_occured: Option<ErrorReported>,
@@ -58,7 +58,7 @@ pub trait Qualif {
     /// from a call to another function.
     ///
     /// It also determines the `Qualif`s for primitive types.
-    fn in_any_value_of_ty(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool;
+    fn in_any_value_of_ty<'tcx>(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool;
 
     /// Returns `true` if this `Qualif` is inherent to the given struct or enum.
     ///
@@ -68,7 +68,7 @@ pub trait Qualif {
     /// with a custom `Drop` impl is inherently `NeedsDrop`.
     ///
     /// Returning `true` for `in_adt_inherently` but `false` for `in_any_value_of_ty` is unsound.
-    fn in_adt_inherently(
+    fn in_adt_inherently<'tcx>(
         cx: &ConstCx<'_, 'tcx>,
         adt: &'tcx AdtDef,
         substs: SubstsRef<'tcx>,
@@ -89,11 +89,15 @@ impl Qualif for HasMutInterior {
         qualifs.has_mut_interior
     }
 
-    fn in_any_value_of_ty(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
+    fn in_any_value_of_ty<'tcx>(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
         !ty.is_freeze(cx.tcx.at(DUMMY_SP), cx.param_env)
     }
 
-    fn in_adt_inherently(cx: &ConstCx<'_, 'tcx>, adt: &'tcx AdtDef, _: SubstsRef<'tcx>) -> bool {
+    fn in_adt_inherently<'tcx>(
+        cx: &ConstCx<'_, 'tcx>,
+        adt: &'tcx AdtDef,
+        _: SubstsRef<'tcx>,
+    ) -> bool {
         // Exactly one type, `UnsafeCell`, has the `HasMutInterior` qualif inherently.
         // It arises structurally for all other types.
         Some(adt.did) == cx.tcx.lang_items().unsafe_cell_type()
@@ -115,11 +119,15 @@ impl Qualif for NeedsDrop {
         qualifs.needs_drop
     }
 
-    fn in_any_value_of_ty(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
+    fn in_any_value_of_ty<'tcx>(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
         ty.needs_drop(cx.tcx, cx.param_env)
     }
 
-    fn in_adt_inherently(cx: &ConstCx<'_, 'tcx>, adt: &'tcx AdtDef, _: SubstsRef<'tcx>) -> bool {
+    fn in_adt_inherently<'tcx>(
+        cx: &ConstCx<'_, 'tcx>,
+        adt: &'tcx AdtDef,
+        _: SubstsRef<'tcx>,
+    ) -> bool {
         adt.has_dtor(cx.tcx)
     }
 }
@@ -137,7 +145,7 @@ impl Qualif for NeedsNonConstDrop {
         qualifs.needs_non_const_drop
     }
 
-    fn in_any_value_of_ty(cx: &ConstCx<'_, 'tcx>, mut ty: Ty<'tcx>) -> bool {
+    fn in_any_value_of_ty<'tcx>(cx: &ConstCx<'_, 'tcx>, mut ty: Ty<'tcx>) -> bool {
         // Avoid selecting for simple cases.
         match ty::util::needs_drop_components(ty, &cx.tcx.data_layout).as_deref() {
             Ok([]) => return false,
@@ -177,7 +185,11 @@ impl Qualif for NeedsNonConstDrop {
         )
     }
 
-    fn in_adt_inherently(cx: &ConstCx<'_, 'tcx>, adt: &'tcx AdtDef, _: SubstsRef<'tcx>) -> bool {
+    fn in_adt_inherently<'tcx>(
+        cx: &ConstCx<'_, 'tcx>,
+        adt: &'tcx AdtDef,
+        _: SubstsRef<'tcx>,
+    ) -> bool {
         adt.has_non_const_dtor(cx.tcx)
     }
 }
@@ -192,7 +204,7 @@ impl Qualif for CustomEq {
         qualifs.custom_eq
     }
 
-    fn in_any_value_of_ty(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
+    fn in_any_value_of_ty<'tcx>(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
         // If *any* component of a composite data type does not implement `Structural{Partial,}Eq`,
         // we know that at least some values of that type are not structural-match. I say "some"
         // because that component may be part of an enum variant (e.g.,
@@ -202,7 +214,7 @@ impl Qualif for CustomEq {
         traits::search_for_structural_match_violation(id, cx.body.span, cx.tcx, ty).is_some()
     }
 
-    fn in_adt_inherently(
+    fn in_adt_inherently<'tcx>(
         cx: &ConstCx<'_, 'tcx>,
         adt: &'tcx AdtDef,
         substs: SubstsRef<'tcx>,
@@ -215,7 +227,11 @@ impl Qualif for CustomEq {
 // FIXME: Use `mir::visit::Visitor` for the `in_*` functions if/when it supports early return.
 
 /// Returns `true` if this `Rvalue` contains qualif `Q`.
-pub fn in_rvalue<Q, F>(cx: &ConstCx<'_, 'tcx>, in_local: &mut F, rvalue: &Rvalue<'tcx>) -> bool
+pub fn in_rvalue<'tcx, Q, F>(
+    cx: &ConstCx<'_, 'tcx>,
+    in_local: &mut F,
+    rvalue: &Rvalue<'tcx>,
+) -> bool
 where
     Q: Qualif,
     F: FnMut(Local) -> bool,
@@ -270,7 +286,7 @@ where
 }
 
 /// Returns `true` if this `Place` contains qualif `Q`.
-pub fn in_place<Q, F>(cx: &ConstCx<'_, 'tcx>, in_local: &mut F, place: PlaceRef<'tcx>) -> bool
+pub fn in_place<'tcx, Q, F>(cx: &ConstCx<'_, 'tcx>, in_local: &mut F, place: PlaceRef<'tcx>) -> bool
 where
     Q: Qualif,
     F: FnMut(Local) -> bool,
@@ -302,7 +318,11 @@ where
 }
 
 /// Returns `true` if this `Operand` contains qualif `Q`.
-pub fn in_operand<Q, F>(cx: &ConstCx<'_, 'tcx>, in_local: &mut F, operand: &Operand<'tcx>) -> bool
+pub fn in_operand<'tcx, Q, F>(
+    cx: &ConstCx<'_, 'tcx>,
+    in_local: &mut F,
+    operand: &Operand<'tcx>,
+) -> bool
 where
     Q: Qualif,
     F: FnMut(Local) -> bool,
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/resolver.rs b/compiler/rustc_const_eval/src/transform/check_consts/resolver.rs
index 249b4ea0602c1..fd7febc17a3a7 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/resolver.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/resolver.rs
@@ -28,7 +28,7 @@ struct TransferFunction<'a, 'mir, 'tcx, Q> {
     _qualif: PhantomData<Q>,
 }
 
-impl<Q> TransferFunction<'a, 'mir, 'tcx, Q>
+impl<'a, 'mir, 'tcx, Q> TransferFunction<'a, 'mir, 'tcx, Q>
 where
     Q: Qualif,
 {
@@ -127,7 +127,7 @@ where
     }
 }
 
-impl<Q> Visitor<'tcx> for TransferFunction<'_, '_, 'tcx, Q>
+impl<'tcx, Q> Visitor<'tcx> for TransferFunction<'_, '_, 'tcx, Q>
 where
     Q: Qualif,
 {
@@ -330,7 +330,7 @@ impl JoinSemiLattice for State {
     }
 }
 
-impl<Q> AnalysisDomain<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
+impl<'tcx, Q> AnalysisDomain<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
 where
     Q: Qualif,
 {
@@ -350,7 +350,7 @@ where
     }
 }
 
-impl<Q> Analysis<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
+impl<'tcx, Q> Analysis<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
 where
     Q: Qualif,
 {
diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs
index 3c06074a1b33f..1537de993d197 100644
--- a/compiler/rustc_const_eval/src/transform/promote_consts.rs
+++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs
@@ -168,8 +168,8 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
     }
 }
 
-pub fn collect_temps_and_candidates(
-    ccx: &ConstCx<'mir, 'tcx>,
+pub fn collect_temps_and_candidates<'tcx>(
+    ccx: &ConstCx<'_, 'tcx>,
     rpo: &mut ReversePostorder<'_, 'tcx>,
 ) -> (IndexVec<Local, TempState>, Vec<Candidate>) {
     let mut collector = Collector {
@@ -191,7 +191,7 @@ struct Validator<'a, 'tcx> {
     temps: &'a IndexVec<Local, TempState>,
 }
 
-impl std::ops::Deref for Validator<'a, 'tcx> {
+impl<'a, 'tcx> std::ops::Deref for Validator<'a, 'tcx> {
     type Target = ConstCx<'a, 'tcx>;
 
     fn deref(&self) -> &Self::Target {
diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs
index 448a04f76b10a..c3f81a3ab838f 100644
--- a/compiler/rustc_const_eval/src/transform/validate.rs
+++ b/compiler/rustc_const_eval/src/transform/validate.rs
@@ -66,7 +66,7 @@ impl<'tcx> MirPass<'tcx> for Validator {
 ///
 /// The point of this function is to approximate "equal up to subtyping".  However,
 /// the approximation is incorrect as variance is ignored.
-pub fn equal_up_to_regions(
+pub fn equal_up_to_regions<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ParamEnv<'tcx>,
     src: Ty<'tcx>,
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index fdf7a8102a028..1807bd3654fcc 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -522,7 +522,7 @@ pub struct GenericParam<'hir> {
     pub kind: GenericParamKind<'hir>,
 }
 
-impl GenericParam<'hir> {
+impl<'hir> GenericParam<'hir> {
     pub fn bounds_span_for_suggestions(&self) -> Option<Span> {
         self.bounds
             .iter()
@@ -557,7 +557,7 @@ pub struct Generics<'hir> {
     pub span: Span,
 }
 
-impl Generics<'hir> {
+impl<'hir> Generics<'hir> {
     pub const fn empty() -> Generics<'hir> {
         Generics {
             params: &[],
@@ -622,7 +622,7 @@ pub enum WherePredicate<'hir> {
     EqPredicate(WhereEqPredicate<'hir>),
 }
 
-impl WherePredicate<'_> {
+impl<'hir> WherePredicate<'hir> {
     pub fn span(&self) -> Span {
         match self {
             WherePredicate::BoundPredicate(p) => p.span,
@@ -644,7 +644,7 @@ pub struct WhereBoundPredicate<'hir> {
     pub bounds: GenericBounds<'hir>,
 }
 
-impl WhereBoundPredicate<'hir> {
+impl<'hir> WhereBoundPredicate<'hir> {
     /// Returns `true` if `param_def_id` matches the `bounded_ty` of this predicate.
     pub fn is_param_bound(&self, param_def_id: DefId) -> bool {
         let path = match self.bounded_ty.kind {
@@ -1236,7 +1236,7 @@ pub struct Body<'hir> {
     pub generator_kind: Option<GeneratorKind>,
 }
 
-impl Body<'hir> {
+impl<'hir> Body<'hir> {
     pub fn id(&self) -> BodyId {
         BodyId { hir_id: self.value.hir_id }
     }
@@ -2623,7 +2623,7 @@ pub enum VariantData<'hir> {
     Unit(HirId),
 }
 
-impl VariantData<'hir> {
+impl<'hir> VariantData<'hir> {
     /// Return the fields of this variant.
     pub fn fields(&self) -> &'hir [FieldDef<'hir>] {
         match *self {
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 21f89104c4b58..a2f1db3579a8e 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -139,7 +139,7 @@ pub trait Map<'hir> {
 }
 
 // Used when no map is actually available, forcing manual implementation of nested visitors.
-impl Map<'hir> for ! {
+impl<'hir> Map<'hir> for ! {
     fn find(&self, _: HirId) -> Option<Node<'hir>> {
         unreachable!()
     }
diff --git a/compiler/rustc_hir/src/lib.rs b/compiler/rustc_hir/src/lib.rs
index 93224d388c00f..1df9b5f9c78a9 100644
--- a/compiler/rustc_hir/src/lib.rs
+++ b/compiler/rustc_hir/src/lib.rs
@@ -4,7 +4,6 @@
 
 #![feature(const_btree_new)]
 #![feature(crate_visibility_modifier)]
-#![feature(in_band_lifetimes)]
 #![feature(once_cell)]
 #![feature(min_specialization)]
 #![feature(never_type)]
diff --git a/compiler/rustc_hir/src/stable_hash_impls.rs b/compiler/rustc_hir/src/stable_hash_impls.rs
index 6e7b765a0c441..c8d729a999e83 100644
--- a/compiler/rustc_hir/src/stable_hash_impls.rs
+++ b/compiler/rustc_hir/src/stable_hash_impls.rs
@@ -211,7 +211,7 @@ impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Item<'_> {
     }
 }
 
-impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'tcx> {
+impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'tcx> {
     fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
         // We ignore the `nodes` and `bodies` fields since these refer to information included in
         // `hash` which is hashed in the collector and used for the crate hash.
@@ -221,7 +221,7 @@ impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'tcx> {
     }
 }
 
-impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for AttributeMap<'tcx> {
+impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for AttributeMap<'tcx> {
     fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
         // We ignore the `map` since it refers to information included in `hash` which is hashed in
         // the collector and used for the crate hash.
diff --git a/compiler/rustc_mir_transform/src/reveal_all.rs b/compiler/rustc_mir_transform/src/reveal_all.rs
index a717dd3e0cd8a..ee661793a44aa 100644
--- a/compiler/rustc_mir_transform/src/reveal_all.rs
+++ b/compiler/rustc_mir_transform/src/reveal_all.rs
@@ -36,6 +36,9 @@ impl<'tcx> MutVisitor<'tcx> for RevealAllVisitor<'tcx> {
 
     #[inline]
     fn visit_ty(&mut self, ty: &mut Ty<'tcx>, _: TyContext) {
-        *ty = self.tcx.normalize_erasing_regions(self.param_env, ty);
+        // We have to use `try_normalize_erasing_regions` here, since it's
+        // possible that we visit impossible-to-satisfy where clauses here,
+        // see #91745
+        *ty = self.tcx.try_normalize_erasing_regions(self.param_env, *ty).unwrap_or(ty);
     }
 }
diff --git a/compiler/rustc_passes/src/weak_lang_items.rs b/compiler/rustc_passes/src/weak_lang_items.rs
index c6c32e69aab77..61c82f031dd5b 100644
--- a/compiler/rustc_passes/src/weak_lang_items.rs
+++ b/compiler/rustc_passes/src/weak_lang_items.rs
@@ -67,10 +67,16 @@ fn verify<'tcx>(tcx: TyCtxt<'tcx>, items: &lang_items::LanguageItems) {
             } else if item == LangItem::Oom {
                 if !tcx.features().default_alloc_error_handler {
                     tcx.sess.err("`#[alloc_error_handler]` function required, but not found");
-                    tcx.sess.note_without_error("Use `#![feature(default_alloc_error_handler)]` for a default error handler");
+                    tcx.sess.note_without_error("use `#![feature(default_alloc_error_handler)]` for a default error handler");
                 }
             } else {
-                tcx.sess.err(&format!("language item required, but not found: `{}`", name));
+                tcx
+                    .sess
+                    .diagnostic()
+                    .struct_err(&format!("language item required, but not found: `{}`", name))
+                    .note(&format!("this can occur when a binary crate with `#![no_std]` is compiled for a target where `{}` is defined in the standard library", name))
+                    .help(&format!("you may be able to compile for a target that doesn't need `{}`, specify a target with `--target` or in `.cargo/config`", name))
+                    .emit();
             }
         }
     }
diff --git a/compiler/rustc_type_ir/src/lib.rs b/compiler/rustc_type_ir/src/lib.rs
index 91dbbec782f89..f11c93e933996 100644
--- a/compiler/rustc_type_ir/src/lib.rs
+++ b/compiler/rustc_type_ir/src/lib.rs
@@ -559,6 +559,7 @@ impl<CTX> HashStable<CTX> for FloatTy {
 impl<CTX> HashStable<CTX> for InferTy {
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
         use InferTy::*;
+        discriminant(self).hash_stable(ctx, hasher);
         match self {
             TyVar(v) => v.as_u32().hash_stable(ctx, hasher),
             IntVar(v) => v.index.hash_stable(ctx, hasher),
diff --git a/library/alloc/src/collections/binary_heap.rs b/library/alloc/src/collections/binary_heap.rs
index 76fbfa9fc59f7..6fc6002d551be 100644
--- a/library/alloc/src/collections/binary_heap.rs
+++ b/library/alloc/src/collections/binary_heap.rs
@@ -149,6 +149,7 @@ use core::mem::{self, swap, ManuallyDrop};
 use core::ops::{Deref, DerefMut};
 use core::ptr;
 
+use crate::collections::TryReserveError;
 use crate::slice;
 use crate::vec::{self, AsIntoIter, Vec};
 
@@ -953,6 +954,84 @@ impl<T> BinaryHeap<T> {
         self.data.reserve(additional);
     }
 
+    /// Tries to reserve the minimum capacity for exactly `additional`
+    /// elements to be inserted in the given `BinaryHeap<T>`. After calling
+    /// `try_reserve_exact`, capacity will be greater than or equal to
+    /// `self.len() + additional` if it returns `Ok(())`.
+    /// Does nothing if the capacity is already sufficient.
+    ///
+    /// Note that the allocator may give the collection more space than it
+    /// requests. Therefore, capacity can not be relied upon to be precisely
+    /// minimal. Prefer [`try_reserve`] if future insertions are expected.
+    ///
+    /// [`try_reserve`]: BinaryHeap::try_reserve
+    ///
+    /// # Errors
+    ///
+    /// If the capacity overflows, or the allocator reports a failure, then an error
+    /// is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(try_reserve_2)]
+    /// use std::collections::BinaryHeap;
+    /// use std::collections::TryReserveError;
+    ///
+    /// fn find_max_slow(data: &[u32]) -> Result<Option<u32>, TryReserveError> {
+    ///     let mut heap = BinaryHeap::new();
+    ///
+    ///     // Pre-reserve the memory, exiting if we can't
+    ///     heap.try_reserve_exact(data.len())?;
+    ///
+    ///     // Now we know this can't OOM in the middle of our complex work
+    ///     heap.extend(data.iter());
+    ///
+    ///     Ok(heap.pop())
+    /// }
+    /// # find_max_slow(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
+    /// ```
+    #[unstable(feature = "try_reserve_2", issue = "91789")]
+    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
+        self.data.try_reserve_exact(additional)
+    }
+
+    /// Tries to reserve capacity for at least `additional` more elements to be inserted
+    /// in the given `BinaryHeap<T>`. The collection may reserve more space to avoid
+    /// frequent reallocations. After calling `try_reserve`, capacity will be
+    /// greater than or equal to `self.len() + additional`. Does nothing if
+    /// capacity is already sufficient.
+    ///
+    /// # Errors
+    ///
+    /// If the capacity overflows, or the allocator reports a failure, then an error
+    /// is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(try_reserve_2)]
+    /// use std::collections::BinaryHeap;
+    /// use std::collections::TryReserveError;
+    ///
+    /// fn find_max_slow(data: &[u32]) -> Result<Option<u32>, TryReserveError> {
+    ///     let mut heap = BinaryHeap::new();
+    ///
+    ///     // Pre-reserve the memory, exiting if we can't
+    ///     heap.try_reserve(data.len())?;
+    ///
+    ///     // Now we know this can't OOM in the middle of our complex work
+    ///     heap.extend(data.iter());
+    ///
+    ///     Ok(heap.pop())
+    /// }
+    /// # find_max_slow(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
+    /// ```
+    #[unstable(feature = "try_reserve_2", issue = "91789")]
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+        self.data.try_reserve(additional)
+    }
+
     /// Discards as much additional capacity as possible.
     ///
     /// # Examples
diff --git a/library/core/src/mem/maybe_uninit.rs b/library/core/src/mem/maybe_uninit.rs
index 9a29094b52c46..783a4b08ec19f 100644
--- a/library/core/src/mem/maybe_uninit.rs
+++ b/library/core/src/mem/maybe_uninit.rs
@@ -394,10 +394,11 @@ impl<T> MaybeUninit<T> {
     /// // This is undefined behavior. ⚠️
     /// ```
     #[stable(feature = "maybe_uninit", since = "1.36.0")]
+    #[rustc_const_unstable(feature = "const_maybe_uninit_zeroed", issue = "91850")]
     #[must_use]
     #[inline]
     #[rustc_diagnostic_item = "maybe_uninit_zeroed"]
-    pub fn zeroed() -> MaybeUninit<T> {
+    pub const fn zeroed() -> MaybeUninit<T> {
         let mut u = MaybeUninit::<T>::uninit();
         // SAFETY: `u.as_mut_ptr()` points to allocated memory.
         unsafe {
diff --git a/src/test/ui/extern-flag/empty-extern-arg.stderr b/src/test/ui/extern-flag/empty-extern-arg.stderr
index b0628a4f6dd62..39a66c08de098 100644
--- a/src/test/ui/extern-flag/empty-extern-arg.stderr
+++ b/src/test/ui/extern-flag/empty-extern-arg.stderr
@@ -1,6 +1,9 @@
 error: extern location for std does not exist: 
 
 error: language item required, but not found: `eh_personality`
+   |
+   = note: this can occur when a binary crate with `#![no_std]` is compiled for a target where `eh_personality` is defined in the standard library
+   = help: you may be able to compile for a target that doesn't need `eh_personality`, specify a target with `--target` or in `.cargo/config`
 
 error: `#[panic_handler]` function required, but not found
 
diff --git a/src/test/ui/mir/issue-91745.rs b/src/test/ui/mir/issue-91745.rs
new file mode 100644
index 0000000000000..ca3d66b1c8eb7
--- /dev/null
+++ b/src/test/ui/mir/issue-91745.rs
@@ -0,0 +1,21 @@
+// check-pass
+
+pub trait Foo {
+    type Bar;
+}
+
+pub trait Broken {
+    type Assoc;
+    fn broken(&self) where Self::Assoc: Foo;
+}
+
+impl<T> Broken for T {
+    type Assoc = ();
+    fn broken(&self) where Self::Assoc: Foo {
+        let _x: <Self::Assoc as Foo>::Bar;
+    }
+}
+
+fn main() {
+    let _m: &dyn Broken<Assoc=()> = &();
+}
diff --git a/src/test/ui/missing/missing-alloc_error_handler.stderr b/src/test/ui/missing/missing-alloc_error_handler.stderr
index ed84493deb563..995fa7cf85e96 100644
--- a/src/test/ui/missing/missing-alloc_error_handler.stderr
+++ b/src/test/ui/missing/missing-alloc_error_handler.stderr
@@ -1,6 +1,6 @@
 error: `#[alloc_error_handler]` function required, but not found
 
-note: Use `#![feature(default_alloc_error_handler)]` for a default error handler
+note: use `#![feature(default_alloc_error_handler)]` for a default error handler
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/panic-handler/weak-lang-item.stderr b/src/test/ui/panic-handler/weak-lang-item.stderr
index 1f14b20e4514d..cc25f08e33a80 100644
--- a/src/test/ui/panic-handler/weak-lang-item.stderr
+++ b/src/test/ui/panic-handler/weak-lang-item.stderr
@@ -11,6 +11,9 @@ LL | extern crate core as other_core;
    |
 
 error: language item required, but not found: `eh_personality`
+   |
+   = note: this can occur when a binary crate with `#![no_std]` is compiled for a target where `eh_personality` is defined in the standard library
+   = help: you may be able to compile for a target that doesn't need `eh_personality`, specify a target with `--target` or in `.cargo/config`
 
 error: `#[panic_handler]` function required, but not found
 
diff --git a/src/test/ui/traits/vtable/issue-91807.rs b/src/test/ui/traits/vtable/issue-91807.rs
new file mode 100644
index 0000000000000..f435ff09dc3af
--- /dev/null
+++ b/src/test/ui/traits/vtable/issue-91807.rs
@@ -0,0 +1,17 @@
+// check-pass
+// incremental
+
+struct Struct<T>(T);
+
+impl<T> std::ops::Deref for Struct<T> {
+    type Target = dyn Fn(T);
+    fn deref(&self) -> &Self::Target {
+        unimplemented!()
+    }
+}
+
+fn main() {
+    let f = Struct(Default::default());
+    f(0);
+    f(0);
+}