Auto merge of #2803 - RalfJung:rustup, r=RalfJung

Rustup

52 files changed, 190 insertions, 190 deletions

diff --git a/src/tools/cargo b/src/tools/cargo
-Subproject 17b3d0de0897e1c6b8ca347bd39f850bb0a5b9f
+Subproject 9d5b32f503fc099c4064298465add14d4bce11e
diff --git a/src/tools/clippy/clippy_lints/src/dereference.rs b/src/tools/clippy/clippy_lints/src/dereference.rs
index b4543aa2544..644604a2e3f 100644
--- a/src/tools/clippy/clippy_lints/src/dereference.rs
+++ b/src/tools/clippy/clippy_lints/src/dereference.rs
@@ -27,7 +27,7 @@ use rustc_middle::mir::{Rvalue, StatementKind};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::{
     self, Binder, BoundVariableKind, Clause, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
-    ProjectionPredicate, Ty, TyCtxt, TypeVisitable, TypeckResults,
+    ProjectionPredicate, Ty, TyCtxt, TypeVisitableExt, TypeckResults,
 };
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{symbol::sym, Span, Symbol};
@@ -1022,7 +1022,7 @@ fn binding_ty_auto_deref_stability<'tcx>(
                     ))
                     .is_sized(cx.tcx, cx.param_env.without_caller_bounds()),
             ),
-            TyKind::OpaqueDef(..) | TyKind::Infer | TyKind::Typeof(..) | TyKind::TraitObject(..) | TyKind::Err => {
+            TyKind::OpaqueDef(..) | TyKind::Infer | TyKind::Typeof(..) | TyKind::TraitObject(..) | TyKind::Err(_) => {
                 Position::ReborrowStable(precedence)
             },
         };
@@ -1038,7 +1038,7 @@ fn ty_contains_infer(ty: &hir::Ty<'_>) -> bool {
             if self.0
                 || matches!(
                     ty.kind,
-                    TyKind::OpaqueDef(..) | TyKind::Infer | TyKind::Typeof(_) | TyKind::Err
+                    TyKind::OpaqueDef(..) | TyKind::Infer | TyKind::Typeof(_) | TyKind::Err(_)
                 )
             {
                 self.0 = true;
diff --git a/src/tools/clippy/clippy_lints/src/derive.rs b/src/tools/clippy/clippy_lints/src/derive.rs
index 1cdcccd5f14..b8428d66a5d 100644
--- a/src/tools/clippy/clippy_lints/src/derive.rs
+++ b/src/tools/clippy/clippy_lints/src/derive.rs
@@ -514,7 +514,7 @@ fn param_env_for_derived_eq(tcx: TyCtxt<'_>, did: DefId, eq_trait_id: DefId) ->
     }
 
     ParamEnv::new(
-        tcx.mk_predicates(ty_predicates.iter().map(|&(p, _)| p).chain(
+        tcx.mk_predicates_from_iter(ty_predicates.iter().map(|&(p, _)| p).chain(
             params.iter().filter(|&&(_, needs_eq)| needs_eq).map(|&(param, _)| {
                 tcx.mk_predicate(Binder::dummy(PredicateKind::Clause(Clause::Trait(TraitPredicate {
                     trait_ref: tcx.mk_trait_ref(eq_trait_id, [tcx.mk_param_from_def(param)]),
diff --git a/src/tools/clippy/clippy_lints/src/doc.rs b/src/tools/clippy/clippy_lints/src/doc.rs
index 0b31e20fc87..6fdb7de25cc 100644
--- a/src/tools/clippy/clippy_lints/src/doc.rs
+++ b/src/tools/clippy/clippy_lints/src/doc.rs
@@ -704,8 +704,10 @@ fn check_code(cx: &LateContext<'_>, text: &str, edition: Edition, span: Span) {
                 let filename = FileName::anon_source_code(&code);
 
                 let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
-                let fallback_bundle =
-                    rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
+                let fallback_bundle = rustc_errors::fallback_fluent_bundle(
+                    rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(),
+                    false
+                );
                 let emitter = EmitterWriter::new(
                     Box::new(io::sink()),
                     None,
diff --git a/src/tools/clippy/clippy_lints/src/eta_reduction.rs b/src/tools/clippy/clippy_lints/src/eta_reduction.rs
index ddade65c515..b2071f4dcb1 100644
--- a/src/tools/clippy/clippy_lints/src/eta_reduction.rs
+++ b/src/tools/clippy/clippy_lints/src/eta_reduction.rs
@@ -11,7 +11,7 @@ use rustc_hir::{Closure, Expr, ExprKind, Param, PatKind, Unsafety};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
 use rustc_middle::ty::binding::BindingMode;
-use rustc_middle::ty::{self, EarlyBinder, SubstsRef, Ty, TypeVisitable};
+use rustc_middle::ty::{self, EarlyBinder, SubstsRef, Ty, TypeVisitableExt};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::sym;
 
diff --git a/src/tools/clippy/clippy_lints/src/lib.rs b/src/tools/clippy/clippy_lints/src/lib.rs
index 565c5b7af00..9011f0896a0 100644
--- a/src/tools/clippy/clippy_lints/src/lib.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.rs
@@ -42,6 +42,7 @@ extern crate rustc_session;
 extern crate rustc_span;
 extern crate rustc_target;
 extern crate rustc_trait_selection;
+extern crate thin_vec;
 
 #[macro_use]
 extern crate clippy_utils;
diff --git a/src/tools/clippy/clippy_lints/src/loops/never_loop.rs b/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
index 14f161f5102..d7e00047312 100644
--- a/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
@@ -224,7 +224,7 @@ fn never_loop_expr(expr: &Expr<'_>, ignore_ids: &mut Vec<HirId>, main_loop_id: H
         | ExprKind::Path(_)
         | ExprKind::ConstBlock(_)
         | ExprKind::Lit(_)
-        | ExprKind::Err => NeverLoopResult::Otherwise,
+        | ExprKind::Err(_) => NeverLoopResult::Otherwise,
     }
 }
 
diff --git a/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs b/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs
index f587c69f730..b33a2478172 100644
--- a/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs
@@ -341,7 +341,7 @@ impl<'a, 'tcx> Visitor<'tcx> for SigDropHelper<'a, 'tcx> {
             ExprKind::ConstBlock(_) |
             ExprKind::Continue(_) |
             ExprKind::DropTemps(_) |
-            ExprKind::Err |
+            ExprKind::Err(_) |
             ExprKind::InlineAsm(_) |
             ExprKind::Let(_) |
             ExprKind::Lit(_) |
diff --git a/src/tools/clippy/clippy_lints/src/methods/needless_collect.rs b/src/tools/clippy/clippy_lints/src/methods/needless_collect.rs
index 8ddbacc3d7a..0b0c6adc504 100644
--- a/src/tools/clippy/clippy_lints/src/methods/needless_collect.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/needless_collect.rs
@@ -173,7 +173,7 @@ fn is_contains_sig(cx: &LateContext<'_>, call_id: HirId, iter_expr: &Expr<'_>) -
         && let Some(iter_item) = cx.tcx
             .associated_items(iter_trait)
             .find_by_name_and_kind(cx.tcx, Ident::with_dummy_span(Symbol::intern("Item")), AssocKind::Type, iter_trait)
-        && let substs = cx.tcx.intern_substs(&[GenericArg::from(typeck.expr_ty_adjusted(iter_expr))])
+        && let substs = cx.tcx.mk_substs(&[GenericArg::from(typeck.expr_ty_adjusted(iter_expr))])
         && let proj_ty = cx.tcx.mk_projection(iter_item.def_id, substs)
         && let Ok(item_ty) = cx.tcx.try_normalize_erasing_regions(cx.param_env, proj_ty)
     {
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
index 4e5af1c7c71..df26b36b7b3 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
@@ -414,7 +414,7 @@ fn can_change_type<'a>(cx: &LateContext<'a>, mut expr: &'a Expr<'a>, mut ty: Ty<
                             }
                         });
 
-                        let new_subst = cx.tcx.mk_substs(
+                        let new_subst = cx.tcx.mk_substs_from_iter(
                             call_substs.iter()
                                 .enumerate()
                                 .map(|(i, t)|
diff --git a/src/tools/clippy/clippy_lints/src/mut_key.rs b/src/tools/clippy/clippy_lints/src/mut_key.rs
index 3cc765108d7..5a533261cad 100644
--- a/src/tools/clippy/clippy_lints/src/mut_key.rs
+++ b/src/tools/clippy/clippy_lints/src/mut_key.rs
@@ -3,7 +3,7 @@ use clippy_utils::{def_path_def_ids, trait_ref_of_method};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::TypeVisitable;
+use rustc_middle::ty::TypeVisitableExt;
 use rustc_middle::ty::{Adt, Array, Ref, Slice, Tuple, Ty};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::def_id::LocalDefId;
diff --git a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
index 996ea6ed723..da3b6fa9899 100644
--- a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
@@ -18,7 +18,7 @@ use rustc_hir_typeck::expr_use_visitor as euv;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::mir::FakeReadCause;
-use rustc_middle::ty::{self, TypeVisitable};
+use rustc_middle::ty::{self, TypeVisitableExt};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::symbol::kw;
diff --git a/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs b/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs
index 24aeb82a37f..d3de9699fe9 100644
--- a/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs
@@ -49,10 +49,10 @@ fn check_op(cx: &LateContext<'_>, expr: &Expr<'_>, other: &Expr<'_>, left: bool)
             (arg, arg.span)
         },
         ExprKind::Call(path, [arg])
-            if path_def_id(cx, path).map_or(false, |id| {
-                if match_def_path(cx, id, &paths::FROM_STR_METHOD) {
+            if path_def_id(cx, path).map_or(false, |did| {
+                if match_def_path(cx, did, &paths::FROM_STR_METHOD) {
                     true
-                } else if cx.tcx.lang_items().from_fn() == Some(id) {
+                } else if cx.tcx.is_diagnostic_item(sym::from_fn, did) {
                     !is_copy(cx, typeck.expr_ty(expr))
                 } else {
                     false
diff --git a/src/tools/clippy/clippy_lints/src/redundant_slicing.rs b/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
index 398329e455b..2fdd775ad48 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
@@ -134,7 +134,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantSlicing {
                 } else if let Some(target_id) = cx.tcx.lang_items().deref_target() {
                     if let Ok(deref_ty) = cx.tcx.try_normalize_erasing_regions(
                         cx.param_env,
-                        cx.tcx.mk_projection(target_id, cx.tcx.intern_substs(&[GenericArg::from(indexed_ty)])),
+                        cx.tcx.mk_projection(target_id, cx.tcx.mk_substs(&[GenericArg::from(indexed_ty)])),
                     ) {
                         if deref_ty == expr_ty {
                             let snip = snippet_with_context(cx, indexed.span, ctxt, "..", &mut app).0;
diff --git a/src/tools/clippy/clippy_lints/src/transmute/transmute_ptr_to_ref.rs b/src/tools/clippy/clippy_lints/src/transmute/transmute_ptr_to_ref.rs
index 54ac04df1c1..6bdb9aa5a26 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/transmute_ptr_to_ref.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/transmute_ptr_to_ref.rs
@@ -6,7 +6,7 @@ use clippy_utils::sugg;
 use rustc_errors::Applicability;
 use rustc_hir::{self as hir, Expr, GenericArg, Mutability, Path, TyKind};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, Ty, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TypeVisitableExt};
 
 /// Checks for `transmute_ptr_to_ref` lint.
 /// Returns `true` if it's triggered, otherwise returns `false`.
diff --git a/src/tools/clippy/clippy_lints/src/transmute/useless_transmute.rs b/src/tools/clippy/clippy_lints/src/transmute/useless_transmute.rs
index 871c3fadbba..56207fe767c 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/useless_transmute.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/useless_transmute.rs
@@ -4,7 +4,7 @@ use clippy_utils::sugg;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, Ty, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TypeVisitableExt};
 
 /// Checks for `useless_transmute` lint.
 /// Returns `true` if it's triggered, otherwise returns `false`.
diff --git a/src/tools/clippy/clippy_lints/src/types/redundant_allocation.rs b/src/tools/clippy/clippy_lints/src/types/redundant_allocation.rs
index f9b9a66b5fa..f7adc9d3555 100644
--- a/src/tools/clippy/clippy_lints/src/types/redundant_allocation.rs
+++ b/src/tools/clippy/clippy_lints/src/types/redundant_allocation.rs
@@ -5,7 +5,7 @@ use rustc_errors::Applicability;
 use rustc_hir::{self as hir, def_id::DefId, QPath, TyKind};
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::LateContext;
-use rustc_middle::ty::TypeVisitable;
+use rustc_middle::ty::TypeVisitableExt;
 use rustc_span::symbol::sym;
 
 use super::{utils, REDUNDANT_ALLOCATION};
diff --git a/src/tools/clippy/clippy_lints/src/types/vec_box.rs b/src/tools/clippy/clippy_lints/src/types/vec_box.rs
index 7a3c7cd8a99..d3062f3d2e3 100644
--- a/src/tools/clippy/clippy_lints/src/types/vec_box.rs
+++ b/src/tools/clippy/clippy_lints/src/types/vec_box.rs
@@ -7,7 +7,7 @@ use rustc_hir::{self as hir, def_id::DefId, GenericArg, QPath, TyKind};
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::LateContext;
 use rustc_middle::ty::layout::LayoutOf;
-use rustc_middle::ty::TypeVisitable;
+use rustc_middle::ty::TypeVisitableExt;
 use rustc_span::symbol::sym;
 
 use super::VEC_BOX;
diff --git a/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs b/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs
index 9f207d32fcf..6e802794f5a 100644
--- a/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs
+++ b/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs
@@ -7,6 +7,7 @@ use rustc_hir::{BorrowKind, Expr, ExprKind, LangItem, Mutability};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::sym;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -54,7 +55,7 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryOwnedEmptyStrings {
                         );
                 } else {
                     if_chain! {
-                        if Some(fun_def_id) == cx.tcx.lang_items().from_fn();
+                        if cx.tcx.is_diagnostic_item(sym::from_fn, fun_def_id);
                         if let [.., last_arg] = args;
                         if let ExprKind::Lit(spanned) = &last_arg.kind;
                         if let LitKind::Str(symbol, _) = spanned.node;
diff --git a/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs b/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
index 7355260ae4a..06d248204c1 100644
--- a/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
+++ b/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
@@ -12,9 +12,9 @@ use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::DUMMY_SP;
-
 use std::cell::Cell;
 use std::mem;
+use thin_vec::{thin_vec, ThinVec};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -214,7 +214,7 @@ macro_rules! always_pat {
 /// Focus on `focus_idx` in `alternatives`,
 /// attempting to extend it with elements of the same constructor `C`
 /// in `alternatives[focus_idx + 1..]`.
-fn transform_with_focus_on_idx(alternatives: &mut Vec<P<Pat>>, focus_idx: usize) -> bool {
+fn transform_with_focus_on_idx(alternatives: &mut ThinVec<P<Pat>>, focus_idx: usize) -> bool {
     // Extract the kind; we'll need to make some changes in it.
     let mut focus_kind = mem::replace(&mut alternatives[focus_idx].kind, PatKind::Wild);
     // We'll focus on `alternatives[focus_idx]`,
@@ -296,7 +296,7 @@ fn extend_with_struct_pat(
     fps1: &mut [ast::PatField],
     rest1: bool,
     start: usize,
-    alternatives: &mut Vec<P<Pat>>,
+    alternatives: &mut ThinVec<P<Pat>>,
 ) -> bool {
     (0..fps1.len()).any(|idx| {
         let pos_in_2 = Cell::new(None); // The element `k`.
@@ -336,9 +336,9 @@ fn extend_with_struct_pat(
 fn extend_with_matching_product(
     targets: &mut [P<Pat>],
     start: usize,
-    alternatives: &mut Vec<P<Pat>>,
+    alternatives: &mut ThinVec<P<Pat>>,
     predicate: impl Fn(&PatKind, &[P<Pat>], usize) -> bool,
-    extract: impl Fn(PatKind) -> Vec<P<Pat>>,
+    extract: impl Fn(PatKind) -> ThinVec<P<Pat>>,
 ) -> bool {
     (0..targets.len()).any(|idx| {
         let tail_or = drain_matching(
@@ -365,14 +365,14 @@ fn take_pat(from: &mut Pat) -> Pat {
 
 /// Extend `target` as an or-pattern with the alternatives
 /// in `tail_or` if there are any and return if there were.
-fn extend_with_tail_or(target: &mut Pat, tail_or: Vec<P<Pat>>) -> bool {
-    fn extend(target: &mut Pat, mut tail_or: Vec<P<Pat>>) {
+fn extend_with_tail_or(target: &mut Pat, tail_or: ThinVec<P<Pat>>) -> bool {
+    fn extend(target: &mut Pat, mut tail_or: ThinVec<P<Pat>>) {
         match target {
             // On an existing or-pattern in the target, append to it.
             Pat { kind: Or(ps), .. } => ps.append(&mut tail_or),
             // Otherwise convert the target to an or-pattern.
             target => {
-                let mut init_or = vec![P(take_pat(target))];
+                let mut init_or = thin_vec![P(take_pat(target))];
                 init_or.append(&mut tail_or);
                 target.kind = Or(init_or);
             },
@@ -391,26 +391,42 @@ fn extend_with_tail_or(target: &mut Pat, tail_or: Vec<P<Pat>>) -> bool {
 // Only elements beginning with `start` are considered for extraction.
 fn drain_matching(
     start: usize,
-    alternatives: &mut Vec<P<Pat>>,
+    alternatives: &mut ThinVec<P<Pat>>,
     predicate: impl Fn(&PatKind) -> bool,
     extract: impl Fn(PatKind) -> P<Pat>,
-) -> Vec<P<Pat>> {
-    let mut tail_or = vec![];
+) -> ThinVec<P<Pat>> {
+    let mut tail_or = ThinVec::new();
     let mut idx = 0;
-    for pat in alternatives.drain_filter(|p| {
-        // Check if we should extract, but only if `idx >= start`.
+
+    // If `ThinVec` had the `drain_filter` method, this loop could be rewritten
+    // like so:
+    // 
+    //   for pat in alternatives.drain_filter(|p| {
+    //       // Check if we should extract, but only if `idx >= start`.
+    //       idx += 1;
+    //       idx > start && predicate(&p.kind)
+    //   }) {
+    //       tail_or.push(extract(pat.into_inner().kind));
+    //   }
+    let mut i = 0;
+    while i < alternatives.len() {
         idx += 1;
-        idx > start && predicate(&p.kind)
-    }) {
-        tail_or.push(extract(pat.into_inner().kind));
+        // Check if we should extract, but only if `idx >= start`.
+	if idx > start && predicate(&alternatives[i].kind) {
+	    let pat = alternatives.remove(i);
+            tail_or.push(extract(pat.into_inner().kind));
+	} else {
+	    i += 1;
+	}
     }
+
     tail_or
 }
 
 fn extend_with_matching(
     target: &mut Pat,
     start: usize,
-    alternatives: &mut Vec<P<Pat>>,
+    alternatives: &mut ThinVec<P<Pat>>,
     predicate: impl Fn(&PatKind) -> bool,
     extract: impl Fn(PatKind) -> P<Pat>,
 ) -> bool {
diff --git a/src/tools/clippy/clippy_lints/src/useless_conversion.rs b/src/tools/clippy/clippy_lints/src/useless_conversion.rs
index a95e7b61374..fede625f72a 100644
--- a/src/tools/clippy/clippy_lints/src/useless_conversion.rs
+++ b/src/tools/clippy/clippy_lints/src/useless_conversion.rs
@@ -161,7 +161,7 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
                         }
 
                         if_chain! {
-                            if Some(def_id) == cx.tcx.lang_items().from_fn();
+                            if cx.tcx.is_diagnostic_item(sym::from_fn, def_id);
                             if same_type_and_consts(a, b);
 
                             then {
diff --git a/src/tools/clippy/clippy_lints/src/utils/author.rs b/src/tools/clippy/clippy_lints/src/utils/author.rs
index bd7daf0773c..c37e5bb6716 100644
--- a/src/tools/clippy/clippy_lints/src/utils/author.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/author.rs
@@ -588,7 +588,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                     },
                 }
             },
-            ExprKind::Err => kind!("Err"),
+            ExprKind::Err(_) => kind!("Err"),
             ExprKind::DropTemps(expr) => {
                 bind!(self, expr);
                 kind!("DropTemps({expr})");
diff --git a/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs b/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs
index 6cf2a955fd5..93e4b023c5c 100644
--- a/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs
+++ b/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs
@@ -5,7 +5,7 @@ use rustc_hir::{self as hir, HirId, ItemKind, Node};
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::layout::LayoutOf as _;
-use rustc_middle::ty::{Adt, Ty, TypeVisitable};
+use rustc_middle::ty::{Adt, Ty, TypeVisitableExt};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils.rs b/src/tools/clippy/clippy_utils/src/ast_utils.rs
index 9d0263e93be..d82098523e3 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils.rs
@@ -144,7 +144,8 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
         (_, Paren(r)) => eq_expr(l, r),
         (Err, Err) => true,
         (Box(l), Box(r)) | (Try(l), Try(r)) | (Await(l), Await(r)) => eq_expr(l, r),
-        (Array(l), Array(r)) | (Tup(l), Tup(r)) => over(l, r, |l, r| eq_expr(l, r)),
+        (Array(l), Array(r)) => over(l, r, |l, r| eq_expr(l, r)),
+        (Tup(l), Tup(r)) => over(l, r, |l, r| eq_expr(l, r)),
         (Repeat(le, ls), Repeat(re, rs)) => eq_expr(le, re) && eq_expr(&ls.value, &rs.value),
         (Call(lc, la), Call(rc, ra)) => eq_expr(lc, rc) && over(la, ra, |l, r| eq_expr(l, r)),
         (
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index 8b00ce2cc25..bb8890dcaf9 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -237,7 +237,7 @@ pub fn constant<'tcx>(
         typeck_results,
         param_env: lcx.param_env,
         needed_resolution: false,
-        substs: lcx.tcx.intern_substs(&[]),
+        substs: ty::List::empty(),
     };
     cx.expr(e).map(|cst| (cst, cx.needed_resolution))
 }
@@ -306,7 +306,7 @@ pub fn constant_context<'a, 'tcx>(
         typeck_results,
         param_env: lcx.param_env,
         needed_resolution: false,
-        substs: lcx.tcx.intern_substs(&[]),
+        substs: ty::List::empty(),
     }
 }
 
diff --git a/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs b/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
index 6ff7728374f..ee2f816f181 100644
--- a/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
+++ b/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
@@ -193,7 +193,7 @@ fn expr_eagerness<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> EagernessS
                 | ExprKind::Ret(_)
                 | ExprKind::InlineAsm(_)
                 | ExprKind::Yield(..)
-                | ExprKind::Err => {
+                | ExprKind::Err(_) => {
                     self.eagerness = ForceNoChange;
                     return;
                 },
diff --git a/src/tools/clippy/clippy_utils/src/hir_utils.rs b/src/tools/clippy/clippy_utils/src/hir_utils.rs
index 2bbe1a19b62..0603755f8a9 100644
--- a/src/tools/clippy/clippy_utils/src/hir_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/hir_utils.rs
@@ -714,7 +714,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                 }
                 self.hash_pat(pat);
             },
-            ExprKind::Err => {},
+            ExprKind::Err(_) => {},
             ExprKind::Lit(ref l) => {
                 l.node.hash(&mut self.s);
             },
@@ -986,7 +986,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
             TyKind::Typeof(anon_const) => {
                 self.hash_body(anon_const.body);
             },
-            TyKind::Err | TyKind::Infer | TyKind::Never => {},
+            TyKind::Err(_) | TyKind::Infer | TyKind::Never => {},
         }
     }
 
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index b2edd1bbfef..f02f8ecb43d 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -104,7 +104,7 @@ use rustc_middle::ty::fast_reject::SimplifiedType::{
     PtrSimplifiedType, SliceSimplifiedType, StrSimplifiedType, UintSimplifiedType,
 };
 use rustc_middle::ty::{
-    layout::IntegerExt, BorrowKind, ClosureKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeVisitable, UpvarCapture,
+    layout::IntegerExt, BorrowKind, ClosureKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeVisitableExt, UpvarCapture,
 };
 use rustc_middle::ty::{FloatTy, IntTy, UintTy};
 use rustc_span::hygiene::{ExpnKind, MacroKind};
diff --git a/src/tools/clippy/clippy_utils/src/mir/possible_borrower.rs b/src/tools/clippy/clippy_utils/src/mir/possible_borrower.rs
index e9dc7351b58..920ce8e655b 100644
--- a/src/tools/clippy/clippy_utils/src/mir/possible_borrower.rs
+++ b/src/tools/clippy/clippy_utils/src/mir/possible_borrower.rs
@@ -4,7 +4,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_index::bit_set::{BitSet, HybridBitSet};
 use rustc_lint::LateContext;
 use rustc_middle::mir::{self, visit::Visitor as _, Mutability};
-use rustc_middle::ty::{self, visit::ir::TypeVisitor, TyCtxt};
+use rustc_middle::ty::{self, visit::TypeVisitor, TyCtxt};
 use rustc_mir_dataflow::{impls::MaybeStorageLive, Analysis, ResultsCursor};
 use std::borrow::Cow;
 use std::ops::ControlFlow;
diff --git a/src/tools/clippy/clippy_utils/src/sugg.rs b/src/tools/clippy/clippy_utils/src/sugg.rs
index 78fb2e0eb7e..11ca81cfe6c 100644
--- a/src/tools/clippy/clippy_utils/src/sugg.rs
+++ b/src/tools/clippy/clippy_utils/src/sugg.rs
@@ -157,7 +157,7 @@ impl<'a> Sugg<'a> {
             | hir::ExprKind::Ret(..)
             | hir::ExprKind::Struct(..)
             | hir::ExprKind::Tup(..)
-            | hir::ExprKind::Err => Sugg::NonParen(get_snippet(expr.span)),
+            | hir::ExprKind::Err(_) => Sugg::NonParen(get_snippet(expr.span)),
             hir::ExprKind::DropTemps(inner) => Self::hir_from_snippet(inner, get_snippet),
             hir::ExprKind::Assign(lhs, rhs, _) => {
                 Sugg::BinOp(AssocOp::Assign, get_snippet(lhs.span), get_snippet(rhs.span))
diff --git a/src/tools/clippy/clippy_utils/src/ty.rs b/src/tools/clippy/clippy_utils/src/ty.rs
index 2ed301fcc22..f8ec4bb5493 100644
--- a/src/tools/clippy/clippy_utils/src/ty.rs
+++ b/src/tools/clippy/clippy_utils/src/ty.rs
@@ -17,8 +17,8 @@ use rustc_lint::LateContext;
 use rustc_middle::mir::interpret::{ConstValue, Scalar};
 use rustc_middle::ty::{
     self, AdtDef, AliasTy, AssocKind, Binder, BoundRegion, DefIdTree, FnSig, IntTy, List, ParamEnv, Predicate,
-    PredicateKind, Region, RegionKind, SubstsRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, ir::TypeVisitor, UintTy,
-    VariantDef, VariantDiscr,
+    PredicateKind, Region, RegionKind, SubstsRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, UintTy,
+    VariantDef, VariantDiscr, TypeVisitableExt,
 };
 use rustc_middle::ty::{GenericArg, GenericArgKind};
 use rustc_span::symbol::Ident;
@@ -237,7 +237,7 @@ pub fn implements_trait_with_env<'tcx>(
         kind: TypeVariableOriginKind::MiscVariable,
         span: DUMMY_SP,
     };
-    let ty_params = tcx.mk_substs(
+    let ty_params = tcx.mk_substs_from_iter(
         ty_params
             .into_iter()
             .map(|arg| arg.unwrap_or_else(|| infcx.next_ty_var(orig).into())),
@@ -847,7 +847,7 @@ pub fn for_each_top_level_late_bound_region<B>(
                 ControlFlow::Continue(())
             }
         }
-        fn visit_binder<T: TypeVisitable<'tcx>>(&mut self, t: &Binder<'tcx, T>) -> ControlFlow<Self::BreakTy> {
+        fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &Binder<'tcx, T>) -> ControlFlow<Self::BreakTy> {
             self.index += 1;
             let res = t.super_visit_with(self);
             self.index -= 1;
@@ -1065,7 +1065,7 @@ pub fn make_projection<'tcx>(
         tcx,
         container_id,
         assoc_ty,
-        tcx.mk_substs(substs.into_iter().map(Into::into)),
+        tcx.mk_substs_from_iter(substs.into_iter().map(Into::into)),
     )
 }
 
diff --git a/src/tools/clippy/clippy_utils/src/visitors.rs b/src/tools/clippy/clippy_utils/src/visitors.rs
index 00073bcd82a..d27a20bd4df 100644
--- a/src/tools/clippy/clippy_utils/src/visitors.rs
+++ b/src/tools/clippy/clippy_utils/src/visitors.rs
@@ -665,7 +665,7 @@ pub fn for_each_unconsumed_temporary<'tcx, B>(
             | ExprKind::Path(_)
             | ExprKind::Continue(_)
             | ExprKind::InlineAsm(_)
-            | ExprKind::Err => (),
+            | ExprKind::Err(_) => (),
         }
         ControlFlow::Continue(())
     }
diff --git a/src/tools/clippy/src/driver.rs b/src/tools/clippy/src/driver.rs
index e45835efe74..9ac849aecf1 100644
--- a/src/tools/clippy/src/driver.rs
+++ b/src/tools/clippy/src/driver.rs
@@ -209,7 +209,10 @@ fn report_clippy_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str) {
     // Separate the output with an empty line
     eprintln!();
 
-    let fallback_bundle = rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
+    let fallback_bundle = rustc_errors::fallback_fluent_bundle(
+        rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(),
+        false
+    );
     let emitter = Box::new(rustc_errors::emitter::EmitterWriter::stderr(
         rustc_errors::ColorConfig::Auto,
         None,
diff --git a/src/tools/clippy/tests/ui/missing_doc_impl.stderr b/src/tools/clippy/tests/ui/missing_doc_impl.stderr
index f22fa19dbca..b410f56e167 100644
--- a/src/tools/clippy/tests/ui/missing_doc_impl.stderr
+++ b/src/tools/clippy/tests/ui/missing_doc_impl.stderr
@@ -51,13 +51,13 @@ LL | |     fn foo_with_impl(&self) {}
 LL | | }
    | |_^
 
-error: missing documentation for an associated function
+error: missing documentation for a method
   --> $DIR/missing_doc_impl.rs:44:5
    |
 LL |     fn foo(&self);
    |     ^^^^^^^^^^^^^^
 
-error: missing documentation for an associated function
+error: missing documentation for a method
   --> $DIR/missing_doc_impl.rs:45:5
    |
 LL |     fn foo_with_impl(&self) {}
diff --git a/src/tools/compiletest/Cargo.toml b/src/tools/compiletest/Cargo.toml
index deed6fbd439..0db043a4fca 100644
--- a/src/tools/compiletest/Cargo.toml
+++ b/src/tools/compiletest/Cargo.toml
@@ -16,7 +16,7 @@ regex = "1.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 rustfix = "0.6.0"
-lazy_static = "1.0"
+once_cell = "1.16.0"
 walkdir = "2"
 glob = "0.3.0"
 lazycell = "1.3.0"
@@ -25,5 +25,5 @@ lazycell = "1.3.0"
 libc = "0.2"
 
 [target.'cfg(windows)'.dependencies]
-miow = "0.3"
+miow = "0.5"
 winapi = { version = "0.3", features = ["winerror"] }
diff --git a/src/tools/compiletest/src/errors.rs b/src/tools/compiletest/src/errors.rs
index 054235ec16d..c33e66e02ac 100644
--- a/src/tools/compiletest/src/errors.rs
+++ b/src/tools/compiletest/src/errors.rs
@@ -7,7 +7,7 @@ use std::io::BufReader;
 use std::path::Path;
 use std::str::FromStr;
 
-use lazy_static::lazy_static;
+use once_cell::sync::Lazy;
 use regex::Regex;
 use tracing::*;
 
@@ -117,10 +117,8 @@ fn parse_expected(
     //     //~^^^^^
     //     //[cfg1]~
     //     //[cfg1,cfg2]~^^
-    lazy_static! {
-        static ref RE: Regex =
-            Regex::new(r"//(?:\[(?P<cfgs>[\w,]+)])?~(?P<adjust>\||\^*)").unwrap();
-    }
+    static RE: Lazy<Regex> =
+        Lazy::new(|| Regex::new(r"//(?:\[(?P<cfgs>[\w,]+)])?~(?P<adjust>\||\^*)").unwrap());
 
     let captures = RE.captures(line)?;
 
diff --git a/src/tools/compiletest/src/main.rs b/src/tools/compiletest/src/main.rs
index c648b2f12f1..1760c29ec66 100644
--- a/src/tools/compiletest/src/main.rs
+++ b/src/tools/compiletest/src/main.rs
@@ -588,7 +588,8 @@ fn modified_tests(config: &Config, dir: &Path) -> Result<Vec<PathBuf>, String> {
     let full_paths = {
         let mut full_paths: Vec<PathBuf> = all_paths
             .into_iter()
-            .map(|f| fs::canonicalize(&f).unwrap().with_extension("").with_extension("rs"))
+            .map(|f| PathBuf::from(f).with_extension("").with_extension("rs"))
+            .filter_map(|f| if Path::new(&f).exists() { f.canonicalize().ok() } else { None })
             .collect();
         full_paths.dedup();
         full_paths.sort_unstable();
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 51c9a27c83d..7824ef81d7a 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -32,7 +32,7 @@ use std::process::{Child, Command, ExitStatus, Output, Stdio};
 use std::str;
 
 use glob::glob;
-use lazy_static::lazy_static;
+use once_cell::sync::Lazy;
 use tracing::*;
 
 use crate::extract_gdb_version;
@@ -52,9 +52,8 @@ fn disable_error_reporting<F: FnOnce() -> R, R>(f: F) -> R {
     use winapi::um::errhandlingapi::SetErrorMode;
     use winapi::um::winbase::SEM_NOGPFAULTERRORBOX;
 
-    lazy_static! {
-        static ref LOCK: Mutex<()> = Mutex::new(());
-    }
+    static LOCK: Mutex<()> = Mutex::new(());
+
     // Error mode is a global variable, so lock it so only one thread will change it
     let _lock = LOCK.lock().unwrap();
 
@@ -2848,11 +2847,10 @@ impl<'test> TestCx<'test> {
         // the form <crate-name1>.<crate-disambiguator1>-in-<crate-name2>.<crate-disambiguator2>,
         // remove all crate-disambiguators.
         fn remove_crate_disambiguator_from_cgu(cgu: &str) -> String {
-            lazy_static! {
-                static ref RE: Regex =
-                    Regex::new(r"^[^\.]+(?P<d1>\.[[:alnum:]]+)(-in-[^\.]+(?P<d2>\.[[:alnum:]]+))?")
-                        .unwrap();
-            }
+            static RE: Lazy<Regex> = Lazy::new(|| {
+                Regex::new(r"^[^\.]+(?P<d1>\.[[:alnum:]]+)(-in-[^\.]+(?P<d2>\.[[:alnum:]]+))?")
+                    .unwrap()
+            });
 
             let captures =
                 RE.captures(cgu).unwrap_or_else(|| panic!("invalid cgu name encountered: {}", cgu));
@@ -3170,12 +3168,12 @@ impl<'test> TestCx<'test> {
                 // 'uploaded "$TEST_BUILD_DIR/<test_executable>, waiting for result"'
                 // is printed to stdout by the client and then captured in the ProcRes,
                 // so it needs to be removed when comparing the run-pass test execution output
-                lazy_static! {
-                    static ref REMOTE_TEST_RE: Regex = Regex::new(
+                static REMOTE_TEST_RE: Lazy<Regex> = Lazy::new(|| {
+                    Regex::new(
                         "^uploaded \"\\$TEST_BUILD_DIR(/[[:alnum:]_\\-.]+)+\", waiting for result\n"
                     )
-                    .unwrap();
-                }
+                    .unwrap()
+                });
                 REMOTE_TEST_RE
                     .replace(
                         &self.normalize_output(&proc_res.stdout, &self.props.normalize_stdout),
@@ -3620,10 +3618,8 @@ impl<'test> TestCx<'test> {
         // with placeholders as we do not want tests needing updated when compiler source code
         // changes.
         // eg. $SRC_DIR/libcore/mem.rs:323:14 becomes $SRC_DIR/libcore/mem.rs:LL:COL
-        lazy_static! {
-            static ref SRC_DIR_RE: Regex =
-                Regex::new("SRC_DIR(.+):\\d+:\\d+(: \\d+:\\d+)?").unwrap();
-        }
+        static SRC_DIR_RE: Lazy<Regex> =
+            Lazy::new(|| Regex::new("SRC_DIR(.+):\\d+:\\d+(: \\d+:\\d+)?").unwrap());
 
         normalized = SRC_DIR_RE.replace_all(&normalized, "SRC_DIR$1:LL:COL").into_owned();
 
@@ -3634,19 +3630,17 @@ impl<'test> TestCx<'test> {
         // since they duplicate actual errors and make the output hard to read.
         // This mirrors the regex in src/tools/tidy/src/style.rs, please update
         // both if either are changed.
-        lazy_static! {
-            static ref ANNOTATION_RE: Regex = Regex::new("\\s*//(\\[.*\\])?~.*").unwrap();
-        }
+        static ANNOTATION_RE: Lazy<Regex> =
+            Lazy::new(|| Regex::new("\\s*//(\\[.*\\])?~.*").unwrap());
 
         normalized = ANNOTATION_RE.replace_all(&normalized, "").into_owned();
 
         // This code normalizes various hashes in v0 symbol mangling that is
         // emitted in the ui and mir-opt tests.
-        lazy_static! {
-            static ref V0_CRATE_HASH_PREFIX_RE: Regex =
-                Regex::new(r"_R.*?Cs[0-9a-zA-Z]+_").unwrap();
-            static ref V0_CRATE_HASH_RE: Regex = Regex::new(r"Cs[0-9a-zA-Z]+_").unwrap();
-        }
+        static V0_CRATE_HASH_PREFIX_RE: Lazy<Regex> =
+            Lazy::new(|| Regex::new(r"_R.*?Cs[0-9a-zA-Z]+_").unwrap());
+        static V0_CRATE_HASH_RE: Lazy<Regex> =
+            Lazy::new(|| Regex::new(r"Cs[0-9a-zA-Z]+_").unwrap());
 
         const V0_CRATE_HASH_PLACEHOLDER: &str = r"CsCRATE_HASH_";
         if V0_CRATE_HASH_PREFIX_RE.is_match(&normalized) {
@@ -3655,10 +3649,9 @@ impl<'test> TestCx<'test> {
                 V0_CRATE_HASH_RE.replace_all(&normalized, V0_CRATE_HASH_PLACEHOLDER).into_owned();
         }
 
-        lazy_static! {
-            static ref V0_BACK_REF_PREFIX_RE: Regex = Regex::new(r"\(_R.*?B[0-9a-zA-Z]_").unwrap();
-            static ref V0_BACK_REF_RE: Regex = Regex::new(r"B[0-9a-zA-Z]_").unwrap();
-        }
+        static V0_BACK_REF_PREFIX_RE: Lazy<Regex> =
+            Lazy::new(|| Regex::new(r"\(_R.*?B[0-9a-zA-Z]_").unwrap());
+        static V0_BACK_REF_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"B[0-9a-zA-Z]_").unwrap());
 
         const V0_BACK_REF_PLACEHOLDER: &str = r"B<REF>_";
         if V0_BACK_REF_PREFIX_RE.is_match(&normalized) {
@@ -3681,21 +3674,23 @@ impl<'test> TestCx<'test> {
     /// Replaces backslashes in paths with forward slashes, and replaces CRLF line endings
     /// with LF.
     fn normalize_platform_differences(output: &str) -> String {
-        lazy_static! {
-            /// Used to find Windows paths.
-            ///
-            /// It's not possible to detect paths in the error messages generally, but this is a
-            /// decent enough heuristic.
-            static ref PATH_BACKSLASH_RE: Regex = Regex::new(r#"(?x)
+        /// Used to find Windows paths.
+        ///
+        /// It's not possible to detect paths in the error messages generally, but this is a
+        /// decent enough heuristic.
+        static PATH_BACKSLASH_RE: Lazy<Regex> = Lazy::new(|| {
+            Regex::new(
+                r#"(?x)
                 (?:
                   # Match paths that don't include spaces.
                   (?:\\[\pL\pN\.\-_']+)+\.\pL+
                 |
                   # If the path starts with a well-known root, then allow spaces.
                   \$(?:DIR|SRC_DIR|TEST_BUILD_DIR|BUILD_DIR|LIB_DIR)(?:\\[\pL\pN\.\-_' ]+)+
-                )"#
-            ).unwrap();
-        }
+                )"#,
+            )
+            .unwrap()
+        });
 
         let output = output.replace(r"\\", r"\");
 
diff --git a/src/tools/error_index_generator/Cargo.toml b/src/tools/error_index_generator/Cargo.toml
index f4dac6e947e..76c2e330b21 100644
--- a/src/tools/error_index_generator/Cargo.toml
+++ b/src/tools/error_index_generator/Cargo.toml
@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 mdbook = { version = "0.4", default-features = false, features = ["search"] }
+rustc_error_codes = { version = "0.0.0", path = "../../../compiler/rustc_error_codes" }
 
 [[bin]]
 name = "error_index_generator"
diff --git a/src/tools/error_index_generator/main.rs b/src/tools/error_index_generator/main.rs
index 98eda97e236..f984275b164 100644
--- a/src/tools/error_index_generator/main.rs
+++ b/src/tools/error_index_generator/main.rs
@@ -2,9 +2,6 @@
 
 extern crate rustc_driver;
 
-// We use the function we generate from `register_diagnostics!`.
-use crate::error_codes::error_codes;
-
 use std::env;
 use std::error::Error;
 use std::fs::{self, File};
@@ -17,22 +14,6 @@ use std::str::FromStr;
 use mdbook::book::{parse_summary, BookItem, Chapter};
 use mdbook::{Config, MDBook};
 
-macro_rules! register_diagnostics {
-    ($($error_code:ident: $message:expr,)+ ; $($undocumented:ident,)* ) => {
-        pub fn error_codes() -> Vec<(&'static str, Option<&'static str>)> {
-            let mut errors: Vec<(&str, Option<&str>)> = vec![
-                $((stringify!($error_code), Some($message)),)+
-                $((stringify!($undocumented), None),)+
-            ];
-            errors.sort();
-            errors
-        }
-    }
-}
-
-#[path = "../../../compiler/rustc_error_codes/src/error_codes.rs"]
-mod error_codes;
-
 enum OutputFormat {
     HTML,
     Markdown,
@@ -55,11 +36,8 @@ fn render_markdown(output_path: &Path) -> Result<(), Box<dyn Error>> {
 
     write!(output_file, "# Rust Compiler Error Index\n")?;
 
-    for (err_code, description) in error_codes().iter() {
-        match description {
-            Some(ref desc) => write!(output_file, "## {}\n{}\n", err_code, desc)?,
-            None => {}
-        }
+    for (err_code, description) in rustc_error_codes::DIAGNOSTICS.iter() {
+        write!(output_file, "## {}\n{}\n", err_code, description)?
     }
 
     Ok(())
@@ -105,27 +83,23 @@ This page lists all the error codes emitted by the Rust compiler.
 "
     );
 
-    let err_codes = error_codes();
+    let err_codes = rustc_error_codes::DIAGNOSTICS;
     let mut chapters = Vec::with_capacity(err_codes.len());
 
     for (err_code, explanation) in err_codes.iter() {
-        if let Some(explanation) = explanation {
-            introduction.push_str(&format!(" * [{0}](./{0}.html)\n", err_code));
-
-            let content = add_rust_attribute_on_codeblock(explanation);
-            chapters.push(BookItem::Chapter(Chapter {
-                name: err_code.to_string(),
-                content: format!("# Error code {}\n\n{}\n", err_code, content),
-                number: None,
-                sub_items: Vec::new(),
-                // We generate it into the `error_codes` folder.
-                path: Some(PathBuf::from(&format!("{}.html", err_code))),
-                source_path: None,
-                parent_names: Vec::new(),
-            }));
-        } else {
-            introduction.push_str(&format!(" * {}\n", err_code));
-        }
+        introduction.push_str(&format!(" * [{0}](./{0}.html)\n", err_code));
+
+        let content = add_rust_attribute_on_codeblock(explanation);
+        chapters.push(BookItem::Chapter(Chapter {
+            name: err_code.to_string(),
+            content: format!("# Error code {}\n\n{}\n", err_code, content),
+            number: None,
+            sub_items: Vec::new(),
+            // We generate it into the `error_codes` folder.
+            path: Some(PathBuf::from(&format!("{}.html", err_code))),
+            source_path: None,
+            parent_names: Vec::new(),
+        }));
     }
 
     let mut config = Config::from_str(include_str!("book_config.toml"))?;
diff --git a/src/tools/jsondoclint/src/validator.rs b/src/tools/jsondoclint/src/validator.rs
index c6f55410e44..a1f675a3b40 100644
--- a/src/tools/jsondoclint/src/validator.rs
+++ b/src/tools/jsondoclint/src/validator.rs
@@ -71,6 +71,19 @@ impl<'a> Validator<'a> {
         }
     }
 
+    fn check_items(&mut self, id: &Id, items: &[Id]) {
+        let mut visited_ids = HashSet::with_capacity(items.len());
+
+        for item in items {
+            if !visited_ids.insert(item) {
+                self.fail(
+                    id,
+                    ErrorKind::Custom(format!("Duplicated entry in `items` field: `{item:?}`")),
+                );
+            }
+        }
+    }
+
     fn check_item(&mut self, id: &'a Id) {
         if let Some(item) = &self.krate.index.get(id) {
             item.links.values().for_each(|id| self.add_any_id(id));
@@ -83,9 +96,9 @@ impl<'a> Validator<'a> {
                 ItemEnum::Enum(x) => self.check_enum(x),
                 ItemEnum::Variant(x) => self.check_variant(x, id),
                 ItemEnum::Function(x) => self.check_function(x),
-                ItemEnum::Trait(x) => self.check_trait(x),
+                ItemEnum::Trait(x) => self.check_trait(x, id),
                 ItemEnum::TraitAlias(x) => self.check_trait_alias(x),
-                ItemEnum::Impl(x) => self.check_impl(x),
+                ItemEnum::Impl(x) => self.check_impl(x, id),
                 ItemEnum::Typedef(x) => self.check_typedef(x),
                 ItemEnum::OpaqueTy(x) => self.check_opaque_ty(x),
                 ItemEnum::Constant(x) => self.check_constant(x),
@@ -94,7 +107,7 @@ impl<'a> Validator<'a> {
                 ItemEnum::Macro(x) => self.check_macro(x),
                 ItemEnum::ProcMacro(x) => self.check_proc_macro(x),
                 ItemEnum::Primitive(x) => self.check_primitive_type(x),
-                ItemEnum::Module(x) => self.check_module(x),
+                ItemEnum::Module(x) => self.check_module(x, id),
                 // FIXME: Why don't these have their own structs?
                 ItemEnum::ExternCrate { .. } => {}
                 ItemEnum::AssocConst { type_, default: _ } => self.check_type(type_),
@@ -112,7 +125,8 @@ impl<'a> Validator<'a> {
     }
 
     // Core checkers
-    fn check_module(&mut self, module: &'a Module) {
+    fn check_module(&mut self, module: &'a Module, id: &Id) {
+        self.check_items(id, &module.items);
         module.items.iter().for_each(|i| self.add_mod_item_id(i));
     }
 
@@ -181,7 +195,8 @@ impl<'a> Validator<'a> {
         self.check_fn_decl(&x.decl);
     }
 
-    fn check_trait(&mut self, x: &'a Trait) {
+    fn check_trait(&mut self, x: &'a Trait, id: &Id) {
+        self.check_items(id, &x.items);
         self.check_generics(&x.generics);
         x.items.iter().for_each(|i| self.add_trait_item_id(i));
         x.bounds.iter().for_each(|i| self.check_generic_bound(i));
@@ -193,7 +208,8 @@ impl<'a> Validator<'a> {
         x.params.iter().for_each(|i| self.check_generic_bound(i));
     }
 
-    fn check_impl(&mut self, x: &'a Impl) {
+    fn check_impl(&mut self, x: &'a Impl, id: &Id) {
+        self.check_items(id, &x.items);
         self.check_generics(&x.generics);
         if let Some(path) = &x.trait_ {
             self.check_path(path, PathKind::Trait);
diff --git a/src/tools/miri/rust-version b/src/tools/miri/rust-version
index 461add9f508..53ec1ba0821 100644
--- a/src/tools/miri/rust-version
+++ b/src/tools/miri/rust-version
@@ -1 +1 @@
-f715e430aac0de131e2ad21804013ea405722a66
+c4e0cd966062ca67daed20775f4e8a60c28e57df
diff --git a/src/tools/miri/src/eval.rs b/src/tools/miri/src/eval.rs
index ebb71b57ae3..8443e907938 100644
--- a/src/tools/miri/src/eval.rs
+++ b/src/tools/miri/src/eval.rs
@@ -363,7 +363,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
                 tcx,
                 ty::ParamEnv::reveal_all(),
                 start_id,
-                tcx.intern_substs(&[ty::subst::GenericArg::from(main_ret_ty)]),
+                tcx.mk_substs(&[ty::subst::GenericArg::from(main_ret_ty)]),
             )
             .unwrap()
             .unwrap();
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs b/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs
index c82c274524a..f21b4f84c4c 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs
@@ -173,7 +173,7 @@ pub fn layout_of_ty(db: &dyn HirDatabase, ty: &Ty, krate: CrateId) -> Result<Lay
 
             // let pointee = tcx.normalize_erasing_regions(param_env, pointee);
             // if pointee.is_sized(tcx.at(DUMMY_SP), param_env) {
-            //     return Ok(tcx.intern_layout(LayoutS::scalar(cx, data_ptr)));
+            //     return Ok(tcx.mk_layout(LayoutS::scalar(cx, data_ptr)));
             // }
 
             let unsized_part = struct_tail_erasing_lifetimes(db, pointee.clone());
diff --git a/src/tools/rustfmt/src/chains.rs b/src/tools/rustfmt/src/chains.rs
index 39b8d687809..cbe523c6c3c 100644
--- a/src/tools/rustfmt/src/chains.rs
+++ b/src/tools/rustfmt/src/chains.rs
@@ -74,6 +74,8 @@ use crate::utils::{
     rewrite_ident, trimmed_last_line_width, wrap_str,
 };
 
+use thin_vec::ThinVec;
+
 /// Provides the original input contents from the span
 /// of a chain element with trailing spaces trimmed.
 fn format_overflow_style(span: Span, context: &RewriteContext<'_>) -> Option<String> {
@@ -168,7 +170,7 @@ enum ChainItemKind {
     MethodCall(
         ast::PathSegment,
         Vec<ast::GenericArg>,
-        Vec<ptr::P<ast::Expr>>,
+        ThinVec<ptr::P<ast::Expr>>,
     ),
     StructField(symbol::Ident),
     TupleField(symbol::Ident, bool),
diff --git a/src/tools/rustfmt/src/closures.rs b/src/tools/rustfmt/src/closures.rs
index 8fd0fcf8f5c..340113866c4 100644
--- a/src/tools/rustfmt/src/closures.rs
+++ b/src/tools/rustfmt/src/closures.rs
@@ -1,5 +1,6 @@
 use rustc_ast::{ast, ptr};
 use rustc_span::Span;
+use thin_vec::thin_vec;
 
 use crate::attr::get_attrs_from_stmt;
 use crate::config::lists::*;
@@ -150,7 +151,7 @@ fn rewrite_closure_with_block(
     }
 
     let block = ast::Block {
-        stmts: vec![ast::Stmt {
+        stmts: thin_vec![ast::Stmt {
             id: ast::NodeId::root(),
             kind: ast::StmtKind::Expr(ptr::P(body.clone())),
             span: body.span,
diff --git a/src/tools/rustfmt/src/lib.rs b/src/tools/rustfmt/src/lib.rs
index 0c27bcacfb8..b27405efdb7 100644
--- a/src/tools/rustfmt/src/lib.rs
+++ b/src/tools/rustfmt/src/lib.rs
@@ -23,6 +23,7 @@ extern crate rustc_expand;
 extern crate rustc_parse;
 extern crate rustc_session;
 extern crate rustc_span;
+extern crate thin_vec;
 
 // Necessary to pull in object code as the rest of the rustc crates are shipped only as rmeta
 // files.
diff --git a/src/tools/rustfmt/src/modules.rs b/src/tools/rustfmt/src/modules.rs
index 7a0d1736c59..af9a154a6ae 100644
--- a/src/tools/rustfmt/src/modules.rs
+++ b/src/tools/rustfmt/src/modules.rs
@@ -6,6 +6,7 @@ use rustc_ast::ast;
 use rustc_ast::visit::Visitor;
 use rustc_span::symbol::{self, sym, Symbol};
 use rustc_span::Span;
+use thin_vec::ThinVec;
 use thiserror::Error;
 
 use crate::attr::MetaVisitor;
@@ -25,7 +26,7 @@ type FileModMap<'ast> = BTreeMap<FileName, Module<'ast>>;
 #[derive(Debug, Clone)]
 pub(crate) struct Module<'a> {
     ast_mod_kind: Option<Cow<'a, ast::ModKind>>,
-    pub(crate) items: Cow<'a, Vec<rustc_ast::ptr::P<ast::Item>>>,
+    pub(crate) items: Cow<'a, ThinVec<rustc_ast::ptr::P<ast::Item>>>,
     inner_attr: ast::AttrVec,
     pub(crate) span: Span,
 }
@@ -34,7 +35,7 @@ impl<'a> Module<'a> {
     pub(crate) fn new(
         mod_span: Span,
         ast_mod_kind: Option<Cow<'a, ast::ModKind>>,
-        mod_items: Cow<'a, Vec<rustc_ast::ptr::P<ast::Item>>>,
+        mod_items: Cow<'a, ThinVec<rustc_ast::ptr::P<ast::Item>>>,
         mod_attrs: Cow<'a, ast::AttrVec>,
     ) -> Self {
         let inner_attr = mod_attrs
@@ -157,7 +158,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                     Module::new(
                         module_item.item.span,
                         Some(Cow::Owned(sub_mod_kind.clone())),
-                        Cow::Owned(vec![]),
+                        Cow::Owned(ThinVec::new()),
                         Cow::Owned(ast::AttrVec::new()),
                     ),
                 )?;
@@ -169,7 +170,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
     /// Visit modules defined inside macro calls.
     fn visit_mod_outside_ast(
         &mut self,
-        items: Vec<rustc_ast::ptr::P<ast::Item>>,
+        items: ThinVec<rustc_ast::ptr::P<ast::Item>>,
     ) -> Result<(), ModuleResolutionError> {
         for item in items {
             if is_cfg_if(&item) {
@@ -184,7 +185,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                     Module::new(
                         span,
                         Some(Cow::Owned(sub_mod_kind.clone())),
-                        Cow::Owned(vec![]),
+                        Cow::Owned(ThinVec::new()),
                         Cow::Owned(ast::AttrVec::new()),
                     ),
                 )?;
@@ -210,7 +211,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                     Module::new(
                         span,
                         Some(Cow::Borrowed(sub_mod_kind)),
-                        Cow::Owned(vec![]),
+                        Cow::Owned(ThinVec::new()),
                         Cow::Borrowed(&item.attrs),
                     ),
                 )?;
diff --git a/src/tools/rustfmt/src/parse/parser.rs b/src/tools/rustfmt/src/parse/parser.rs
index e0bd065518b..7ab042506bd 100644
--- a/src/tools/rustfmt/src/parse/parser.rs
+++ b/src/tools/rustfmt/src/parse/parser.rs
@@ -6,6 +6,7 @@ use rustc_ast::{ast, ptr};
 use rustc_errors::Diagnostic;
 use rustc_parse::{new_parser_from_file, parser::Parser as RawParser};
 use rustc_span::{sym, Span};
+use thin_vec::ThinVec;
 
 use crate::attr::first_attr_value_str_by_name;
 use crate::parse::session::ParseSess;
@@ -109,7 +110,7 @@ impl<'a> Parser<'a> {
         sess: &'a ParseSess,
         path: &Path,
         span: Span,
-    ) -> Result<(ast::AttrVec, Vec<ptr::P<ast::Item>>, Span), ParserError> {
+    ) -> Result<(ast::AttrVec, ThinVec<ptr::P<ast::Item>>, Span), ParserError> {
         let result = catch_unwind(AssertUnwindSafe(|| {
             let mut parser = new_parser_from_file(sess.inner(), path, Some(span));
             match parser.parse_mod(&TokenKind::Eof) {
diff --git a/src/tools/rustfmt/src/parse/session.rs b/src/tools/rustfmt/src/parse/session.rs
index 9014026b0aa..a64963db6a7 100644
--- a/src/tools/rustfmt/src/parse/session.rs
+++ b/src/tools/rustfmt/src/parse/session.rs
@@ -123,8 +123,10 @@ fn default_handler(
     let emitter = if hide_parse_errors {
         silent_emitter()
     } else {
-        let fallback_bundle =
-            rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
+        let fallback_bundle = rustc_errors::fallback_fluent_bundle(
+            rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(),
+            false,
+        );
         Box::new(EmitterWriter::stderr(
             color_cfg,
             Some(source_map.clone()),
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 4c93f8a16b6..bddfdcfaf19 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -120,6 +120,7 @@ const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
     "dissimilar",
     "dlmalloc",
     "either",
+    "elsa",
     "ena",
     "expect-test",
     "fallible-iterator", // dependency of `thorin`
diff --git a/src/tools/tidy/src/error_codes.rs b/src/tools/tidy/src/error_codes.rs
index dd2fd1911f2..c60caa0d49c 100644
--- a/src/tools/tidy/src/error_codes.rs
+++ b/src/tools/tidy/src/error_codes.rs
@@ -31,7 +31,7 @@ const IGNORE_DOCTEST_CHECK: &[&str] = &["E0464", "E0570", "E0601", "E0602", "E06
 
 // Error codes that don't yet have a UI test. This list will eventually be removed.
 const IGNORE_UI_TEST_CHECK: &[&str] =
-    &["E0461", "E0465", "E0476", "E0514", "E0554", "E0640", "E0717", "E0729"];
+    &["E0461", "E0465", "E0514", "E0554", "E0640", "E0717", "E0729"];
 
 macro_rules! verbose_print {
     ($verbose:expr, $($fmt:tt)*) => {
@@ -45,7 +45,7 @@ pub fn check(root_path: &Path, search_paths: &[&Path], verbose: bool, bad: &mut
     let mut errors = Vec::new();
 
     // Stage 1: create list
-    let error_codes = extract_error_codes(root_path, &mut errors, verbose);
+    let error_codes = extract_error_codes(root_path, &mut errors);
     println!("Found {} error codes", error_codes.len());
     println!("Highest error code: `{}`", error_codes.iter().max().unwrap());
 
@@ -65,18 +65,17 @@ pub fn check(root_path: &Path, search_paths: &[&Path], verbose: bool, bad: &mut
 }
 
 /// Stage 1: Parses a list of error codes from `error_codes.rs`.
-fn extract_error_codes(root_path: &Path, errors: &mut Vec<String>, verbose: bool) -> Vec<String> {
+fn extract_error_codes(root_path: &Path, errors: &mut Vec<String>) -> Vec<String> {
     let path = root_path.join(Path::new(ERROR_CODES_PATH));
     let file =
         fs::read_to_string(&path).unwrap_or_else(|e| panic!("failed to read `{path:?}`: {e}"));
 
     let mut error_codes = Vec::new();
-    let mut reached_undocumented_codes = false;
 
     for line in file.lines() {
         let line = line.trim();
 
-        if !reached_undocumented_codes && line.starts_with('E') {
+        if line.starts_with('E') {
             let split_line = line.split_once(':');
 
             // Extract the error code from the line, emitting a fatal error if it is not in a correct format.
@@ -111,23 +110,6 @@ fn extract_error_codes(root_path: &Path, errors: &mut Vec<String>, verbose: bool
             }
 
             error_codes.push(err_code);
-        } else if reached_undocumented_codes && line.starts_with('E') {
-            let err_code = match line.split_once(',') {
-                None => line,
-                Some((err_code, _)) => err_code,
-            }
-            .to_string();
-
-            verbose_print!(verbose, "warning: Error code `{}` is undocumented.", err_code);
-
-            if error_codes.contains(&err_code) {
-                errors.push(format!("Found duplicate error code: `{}`", err_code));
-            }
-
-            error_codes.push(err_code);
-        } else if line == ";" {
-            // Once we reach the undocumented error codes, adapt to different syntax.
-            reached_undocumented_codes = true;
         }
     }