diff --git a/compiler/rustc_attr_data_structures/src/stability.rs b/compiler/rustc_attr_data_structures/src/stability.rs
index dfda04387ec5a..c2213fc9ed881 100644
--- a/compiler/rustc_attr_data_structures/src/stability.rs
+++ b/compiler/rustc_attr_data_structures/src/stability.rs
@@ -101,16 +101,6 @@ impl PartialConstStability {
     }
 }
 
-#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
-#[derive(HashStable_Generic)]
-pub enum AllowedThroughUnstableModules {
-    /// This does not get a deprecation warning. We still generally would prefer people to use the
-    /// fully stable path, and a warning will likely be emitted in the future.
-    WithoutDeprecation,
-    /// Emit the given deprecation warning.
-    WithDeprecation(Symbol),
-}
-
 /// The available stability levels.
 #[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
 #[derive(HashStable_Generic)]
@@ -147,8 +137,9 @@ pub enum StabilityLevel {
     Stable {
         /// Rust release which stabilized this feature.
         since: StableSince,
-        /// This is `Some` if this item allowed to be referred to on stable via unstable modules.
-        allowed_through_unstable_modules: Option<AllowedThroughUnstableModules>,
+        /// This is `Some` if this item allowed to be referred to on stable via unstable modules;
+        /// the `Symbol` is the deprecation message printed in that case.
+        allowed_through_unstable_modules: Option<Symbol>,
     },
 }
 
diff --git a/compiler/rustc_attr_parsing/src/attributes/stability.rs b/compiler/rustc_attr_parsing/src/attributes/stability.rs
index bfbe51b27d88d..454b8b5de82b5 100644
--- a/compiler/rustc_attr_parsing/src/attributes/stability.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/stability.rs
@@ -6,12 +6,12 @@ use rustc_ast::MetaItem;
 use rustc_ast::attr::AttributeExt;
 use rustc_ast_pretty::pprust;
 use rustc_attr_data_structures::{
-    AllowedThroughUnstableModules, ConstStability, DefaultBodyStability, Stability, StabilityLevel,
-    StableSince, UnstableReason, VERSION_PLACEHOLDER,
+    ConstStability, DefaultBodyStability, Stability, StabilityLevel, StableSince, UnstableReason,
+    VERSION_PLACEHOLDER,
 };
 use rustc_errors::ErrorGuaranteed;
 use rustc_session::Session;
-use rustc_span::{Span, Symbol, sym};
+use rustc_span::{Span, Symbol, kw, sym};
 
 use crate::attributes::util::UnsupportedLiteralReason;
 use crate::{parse_version, session_diagnostics};
@@ -29,10 +29,14 @@ pub fn find_stability(
     for attr in attrs {
         match attr.name_or_empty() {
             sym::rustc_allowed_through_unstable_modules => {
-                allowed_through_unstable_modules = Some(match attr.value_str() {
-                    Some(msg) => AllowedThroughUnstableModules::WithDeprecation(msg),
-                    None => AllowedThroughUnstableModules::WithoutDeprecation,
-                })
+                // The value is mandatory, but avoid ICEs in case such code reaches this function.
+                allowed_through_unstable_modules = Some(attr.value_str().unwrap_or_else(|| {
+                    sess.dcx().span_delayed_bug(
+                        item_sp,
+                        "`#[rustc_allowed_through_unstable_modules]` without deprecation message",
+                    );
+                    kw::Empty
+                }))
             }
             sym::unstable => {
                 if stab.is_some() {
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index 2656e0bb6a452..841cb782bc3bd 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -248,7 +248,98 @@ impl<'tcx> BorrowExplanation<'tcx> {
                         );
                         err.span_label(body.source_info(drop_loc).span, message);
 
-                        if let LocalInfo::BlockTailTemp(info) = local_decl.local_info() {
+                        struct FindLetExpr<'hir> {
+                            span: Span,
+                            result: Option<(Span, &'hir hir::Pat<'hir>, &'hir hir::Expr<'hir>)>,
+                            tcx: TyCtxt<'hir>,
+                        }
+
+                        impl<'hir> rustc_hir::intravisit::Visitor<'hir> for FindLetExpr<'hir> {
+                            type NestedFilter = rustc_middle::hir::nested_filter::OnlyBodies;
+                            fn nested_visit_map(&mut self) -> Self::Map {
+                                self.tcx.hir()
+                            }
+                            fn visit_expr(&mut self, expr: &'hir hir::Expr<'hir>) {
+                                if let hir::ExprKind::If(cond, _conseq, _alt)
+                                | hir::ExprKind::Loop(
+                                    hir::Block {
+                                        expr:
+                                            Some(&hir::Expr {
+                                                kind: hir::ExprKind::If(cond, _conseq, _alt),
+                                                ..
+                                            }),
+                                        ..
+                                    },
+                                    _,
+                                    hir::LoopSource::While,
+                                    _,
+                                ) = expr.kind
+                                    && let hir::ExprKind::Let(hir::LetExpr {
+                                        init: let_expr_init,
+                                        span: let_expr_span,
+                                        pat: let_expr_pat,
+                                        ..
+                                    }) = cond.kind
+                                    && let_expr_init.span.contains(self.span)
+                                {
+                                    self.result =
+                                        Some((*let_expr_span, let_expr_pat, let_expr_init))
+                                } else {
+                                    hir::intravisit::walk_expr(self, expr);
+                                }
+                            }
+                        }
+
+                        if let &LocalInfo::IfThenRescopeTemp { if_then } = local_decl.local_info()
+                            && let hir::Node::Expr(expr) = tcx.hir_node(if_then)
+                            && let hir::ExprKind::If(cond, conseq, alt) = expr.kind
+                            && let hir::ExprKind::Let(&hir::LetExpr {
+                                span: _,
+                                pat,
+                                init,
+                                // FIXME(#101728): enable rewrite when type ascription is
+                                // stabilized again.
+                                ty: None,
+                                recovered: _,
+                            }) = cond.kind
+                            && pat.span.can_be_used_for_suggestions()
+                            && let Ok(pat) = tcx.sess.source_map().span_to_snippet(pat.span)
+                        {
+                            suggest_rewrite_if_let(tcx, expr, &pat, init, conseq, alt, err);
+                        } else if let Some((old, new)) = multiple_borrow_span
+                            && let def_id = body.source.def_id()
+                            && let Some(node) = tcx.hir().get_if_local(def_id)
+                            && let Some(body_id) = node.body_id()
+                            && let hir_body = tcx.hir().body(body_id)
+                            && let mut expr_finder = (FindLetExpr { span: old, result: None, tcx })
+                            && let Some((let_expr_span, let_expr_pat, let_expr_init)) = {
+                                expr_finder.visit_expr(hir_body.value);
+                                expr_finder.result
+                            }
+                            && !let_expr_span.contains(new)
+                        {
+                            // #133941: The `old` expression is at the conditional part of an
+                            // if/while let expression. Adding a semicolon won't work.
+                            // Instead, try suggesting the `matches!` macro or a temporary.
+                            if let_expr_pat
+                                .walk_short(|pat| !matches!(pat.kind, hir::PatKind::Binding(..)))
+                            {
+                                if let Ok(pat_snippet) =
+                                    tcx.sess.source_map().span_to_snippet(let_expr_pat.span)
+                                    && let Ok(init_snippet) =
+                                        tcx.sess.source_map().span_to_snippet(let_expr_init.span)
+                                {
+                                    err.span_suggestion_verbose(
+                                        let_expr_span,
+                                        "consider using the `matches!` macro",
+                                        format!("matches!({init_snippet}, {pat_snippet})"),
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                } else {
+                                    err.note("consider using the `matches!` macro");
+                                }
+                            }
+                        } else if let LocalInfo::BlockTailTemp(info) = local_decl.local_info() {
                             if info.tail_result_is_ignored {
                                 // #85581: If the first mutable borrow's scope contains
                                 // the second borrow, this suggestion isn't helpful.
@@ -281,23 +372,6 @@ impl<'tcx> BorrowExplanation<'tcx> {
                                     Applicability::MaybeIncorrect,
                                 );
                             };
-                        } else if let &LocalInfo::IfThenRescopeTemp { if_then } =
-                            local_decl.local_info()
-                            && let hir::Node::Expr(expr) = tcx.hir_node(if_then)
-                            && let hir::ExprKind::If(cond, conseq, alt) = expr.kind
-                            && let hir::ExprKind::Let(&hir::LetExpr {
-                                span: _,
-                                pat,
-                                init,
-                                // FIXME(#101728): enable rewrite when type ascription is
-                                // stabilized again.
-                                ty: None,
-                                recovered: _,
-                            }) = cond.kind
-                            && pat.span.can_be_used_for_suggestions()
-                            && let Ok(pat) = tcx.sess.source_map().span_to_snippet(pat.span)
-                        {
-                            suggest_rewrite_if_let(tcx, expr, &pat, init, conseq, alt, err);
                         }
                     }
                 }
diff --git a/compiler/rustc_builtin_macros/src/deriving/debug.rs b/compiler/rustc_builtin_macros/src/deriving/debug.rs
index eb01ca3941d83..8ab21986e68a0 100644
--- a/compiler/rustc_builtin_macros/src/deriving/debug.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/debug.rs
@@ -56,7 +56,7 @@ fn show_substructure(cx: &ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) ->
 
     let (ident, vdata, fields) = match substr.fields {
         Struct(vdata, fields) => (substr.type_ident, *vdata, fields),
-        EnumMatching(_, v, fields) => (v.ident, &v.data, fields),
+        EnumMatching(v, fields) => (v.ident, &v.data, fields),
         AllFieldlessEnum(enum_def) => return show_fieldless_enum(cx, span, enum_def, substr),
         EnumDiscr(..) | StaticStruct(..) | StaticEnum(..) => {
             cx.dcx().span_bug(span, "nonsensical .fields in `#[derive(Debug)]`")
diff --git a/compiler/rustc_builtin_macros/src/deriving/decodable.rs b/compiler/rustc_builtin_macros/src/deriving/decodable.rs
deleted file mode 100644
index 6348560496e95..0000000000000
--- a/compiler/rustc_builtin_macros/src/deriving/decodable.rs
+++ /dev/null
@@ -1,215 +0,0 @@
-//! The compiler code necessary for `#[derive(RustcDecodable)]`. See encodable.rs for more.
-
-use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, Expr, MetaItem, Mutability};
-use rustc_expand::base::{Annotatable, ExtCtxt};
-use rustc_span::{Ident, Span, Symbol, sym};
-use thin_vec::{ThinVec, thin_vec};
-
-use crate::deriving::generic::ty::*;
-use crate::deriving::generic::*;
-use crate::deriving::pathvec_std;
-
-pub(crate) fn expand_deriving_rustc_decodable(
-    cx: &ExtCtxt<'_>,
-    span: Span,
-    mitem: &MetaItem,
-    item: &Annotatable,
-    push: &mut dyn FnMut(Annotatable),
-    is_const: bool,
-) {
-    let krate = sym::rustc_serialize;
-    let typaram = sym::__D;
-
-    let trait_def = TraitDef {
-        span,
-        path: Path::new_(vec![krate, sym::Decodable], vec![], PathKind::Global),
-        skip_path_as_bound: false,
-        needs_copy_as_bound_if_packed: true,
-        additional_bounds: Vec::new(),
-        supports_unions: false,
-        methods: vec![MethodDef {
-            name: sym::decode,
-            generics: Bounds {
-                bounds: vec![(typaram, vec![Path::new_(
-                    vec![krate, sym::Decoder],
-                    vec![],
-                    PathKind::Global,
-                )])],
-            },
-            explicit_self: false,
-            nonself_args: vec![(
-                Ref(Box::new(Path(Path::new_local(typaram))), Mutability::Mut),
-                sym::d,
-            )],
-            ret_ty: Path(Path::new_(
-                pathvec_std!(result::Result),
-                vec![
-                    Box::new(Self_),
-                    Box::new(Path(Path::new_(vec![typaram, sym::Error], vec![], PathKind::Local))),
-                ],
-                PathKind::Std,
-            )),
-            attributes: ast::AttrVec::new(),
-            fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
-            combine_substructure: combine_substructure(Box::new(|a, b, c| {
-                decodable_substructure(a, b, c, krate)
-            })),
-        }],
-        associated_types: Vec::new(),
-        is_const,
-    };
-
-    trait_def.expand(cx, mitem, item, push)
-}
-
-fn decodable_substructure(
-    cx: &ExtCtxt<'_>,
-    trait_span: Span,
-    substr: &Substructure<'_>,
-    krate: Symbol,
-) -> BlockOrExpr {
-    let decoder = substr.nonselflike_args[0].clone();
-    let recurse = vec![
-        Ident::new(krate, trait_span),
-        Ident::new(sym::Decodable, trait_span),
-        Ident::new(sym::decode, trait_span),
-    ];
-    let exprdecode = cx.expr_path(cx.path_global(trait_span, recurse));
-    // throw an underscore in front to suppress unused variable warnings
-    let blkarg = Ident::new(sym::_d, trait_span);
-    let blkdecoder = cx.expr_ident(trait_span, blkarg);
-
-    let expr = match substr.fields {
-        StaticStruct(_, summary) => {
-            let nfields = match summary {
-                Unnamed(fields, _) => fields.len(),
-                Named(fields) => fields.len(),
-            };
-            let fn_read_struct_field_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_struct_field]);
-
-            let path = cx.path_ident(trait_span, substr.type_ident);
-            let result =
-                decode_static_fields(cx, trait_span, path, summary, |cx, span, name, field| {
-                    cx.expr_try(
-                        span,
-                        cx.expr_call_global(span, fn_read_struct_field_path.clone(), thin_vec![
-                            blkdecoder.clone(),
-                            cx.expr_str(span, name),
-                            cx.expr_usize(span, field),
-                            exprdecode.clone(),
-                        ]),
-                    )
-                });
-            let result = cx.expr_ok(trait_span, result);
-            let fn_read_struct_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_struct]);
-
-            cx.expr_call_global(trait_span, fn_read_struct_path, thin_vec![
-                decoder,
-                cx.expr_str(trait_span, substr.type_ident.name),
-                cx.expr_usize(trait_span, nfields),
-                cx.lambda1(trait_span, result, blkarg),
-            ])
-        }
-        StaticEnum(_, fields) => {
-            let variant = Ident::new(sym::i, trait_span);
-
-            let mut arms = ThinVec::with_capacity(fields.len() + 1);
-            let mut variants = ThinVec::with_capacity(fields.len());
-
-            let fn_read_enum_variant_arg_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_enum_variant_arg]);
-
-            for (i, &(ident, v_span, ref parts)) in fields.iter().enumerate() {
-                variants.push(cx.expr_str(v_span, ident.name));
-
-                let path = cx.path(trait_span, vec![substr.type_ident, ident]);
-                let decoded =
-                    decode_static_fields(cx, v_span, path, parts, |cx, span, _, field| {
-                        let idx = cx.expr_usize(span, field);
-                        cx.expr_try(
-                            span,
-                            cx.expr_call_global(
-                                span,
-                                fn_read_enum_variant_arg_path.clone(),
-                                thin_vec![blkdecoder.clone(), idx, exprdecode.clone()],
-                            ),
-                        )
-                    });
-
-                arms.push(cx.arm(v_span, cx.pat_lit(v_span, cx.expr_usize(v_span, i)), decoded));
-            }
-
-            arms.push(cx.arm_unreachable(trait_span));
-
-            let result = cx.expr_ok(
-                trait_span,
-                cx.expr_match(trait_span, cx.expr_ident(trait_span, variant), arms),
-            );
-            let lambda = cx.lambda(trait_span, vec![blkarg, variant], result);
-            let variant_array_ref = cx.expr_array_ref(trait_span, variants);
-            let fn_read_enum_variant_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_enum_variant]);
-            let result = cx.expr_call_global(trait_span, fn_read_enum_variant_path, thin_vec![
-                blkdecoder,
-                variant_array_ref,
-                lambda
-            ]);
-            let fn_read_enum_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_enum]);
-
-            cx.expr_call_global(trait_span, fn_read_enum_path, thin_vec![
-                decoder,
-                cx.expr_str(trait_span, substr.type_ident.name),
-                cx.lambda1(trait_span, result, blkarg),
-            ])
-        }
-        _ => cx.dcx().bug("expected StaticEnum or StaticStruct in derive(Decodable)"),
-    };
-    BlockOrExpr::new_expr(expr)
-}
-
-/// Creates a decoder for a single enum variant/struct:
-/// - `outer_pat_path` is the path to this enum variant/struct
-/// - `getarg` should retrieve the `usize`-th field with name `@str`.
-fn decode_static_fields<F>(
-    cx: &ExtCtxt<'_>,
-    trait_span: Span,
-    outer_pat_path: ast::Path,
-    fields: &StaticFields,
-    mut getarg: F,
-) -> P<Expr>
-where
-    F: FnMut(&ExtCtxt<'_>, Span, Symbol, usize) -> P<Expr>,
-{
-    match fields {
-        Unnamed(fields, is_tuple) => {
-            let path_expr = cx.expr_path(outer_pat_path);
-            if matches!(is_tuple, IsTuple::No) {
-                path_expr
-            } else {
-                let fields = fields
-                    .iter()
-                    .enumerate()
-                    .map(|(i, &span)| getarg(cx, span, Symbol::intern(&format!("_field{i}")), i))
-                    .collect();
-
-                cx.expr_call(trait_span, path_expr, fields)
-            }
-        }
-        Named(fields) => {
-            // use the field's span to get nicer error messages.
-            let fields = fields
-                .iter()
-                .enumerate()
-                .map(|(i, &(ident, span, _))| {
-                    let arg = getarg(cx, span, ident.name, i);
-                    cx.field_imm(span, ident, arg)
-                })
-                .collect();
-            cx.expr_struct(trait_span, outer_pat_path, fields)
-        }
-    }
-}
diff --git a/compiler/rustc_builtin_macros/src/deriving/default.rs b/compiler/rustc_builtin_macros/src/deriving/default.rs
index 3c7bebd0f192e..2388b7dd64823 100644
--- a/compiler/rustc_builtin_macros/src/deriving/default.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/default.rs
@@ -42,7 +42,7 @@ pub(crate) fn expand_deriving_default(
                     StaticStruct(_, fields) => {
                         default_struct_substructure(cx, trait_span, substr, fields)
                     }
-                    StaticEnum(enum_def, _) => {
+                    StaticEnum(enum_def) => {
                         default_enum_substructure(cx, trait_span, enum_def, item.span())
                     }
                     _ => cx.dcx().span_bug(trait_span, "method in `derive(Default)`"),
diff --git a/compiler/rustc_builtin_macros/src/deriving/encodable.rs b/compiler/rustc_builtin_macros/src/deriving/encodable.rs
deleted file mode 100644
index 20aacb2caca20..0000000000000
--- a/compiler/rustc_builtin_macros/src/deriving/encodable.rs
+++ /dev/null
@@ -1,284 +0,0 @@
-//! The compiler code necessary to implement the `#[derive(RustcEncodable)]`
-//! (and `RustcDecodable`, in `decodable.rs`) extension. The idea here is that
-//! type-defining items may be tagged with
-//! `#[derive(RustcEncodable, RustcDecodable)]`.
-//!
-//! For example, a type like:
-//!
-//! ```ignore (old code)
-//! #[derive(RustcEncodable, RustcDecodable)]
-//! struct Node { id: usize }
-//! ```
-//!
-//! would generate two implementations like:
-//!
-//! ```ignore (old code)
-//! # struct Node { id: usize }
-//! impl<S: Encoder<E>, E> Encodable<S, E> for Node {
-//!     fn encode(&self, s: &mut S) -> Result<(), E> {
-//!         s.emit_struct("Node", 1, |this| {
-//!             this.emit_struct_field("id", 0, |this| {
-//!                 Encodable::encode(&self.id, this)
-//!                 /* this.emit_usize(self.id) can also be used */
-//!             })
-//!         })
-//!     }
-//! }
-//!
-//! impl<D: Decoder<E>, E> Decodable<D, E> for Node {
-//!     fn decode(d: &mut D) -> Result<Node, E> {
-//!         d.read_struct("Node", 1, |this| {
-//!             match this.read_struct_field("id", 0, |this| Decodable::decode(this)) {
-//!                 Ok(id) => Ok(Node { id: id }),
-//!                 Err(e) => Err(e),
-//!             }
-//!         })
-//!     }
-//! }
-//! ```
-//!
-//! Other interesting scenarios are when the item has type parameters or
-//! references other non-built-in types. A type definition like:
-//!
-//! ```ignore (old code)
-//! # #[derive(RustcEncodable, RustcDecodable)]
-//! # struct Span;
-//! #[derive(RustcEncodable, RustcDecodable)]
-//! struct Spanned<T> { node: T, span: Span }
-//! ```
-//!
-//! would yield functions like:
-//!
-//! ```ignore (old code)
-//! # #[derive(RustcEncodable, RustcDecodable)]
-//! # struct Span;
-//! # struct Spanned<T> { node: T, span: Span }
-//! impl<
-//!     S: Encoder<E>,
-//!     E,
-//!     T: Encodable<S, E>
-//! > Encodable<S, E> for Spanned<T> {
-//!     fn encode(&self, s: &mut S) -> Result<(), E> {
-//!         s.emit_struct("Spanned", 2, |this| {
-//!             this.emit_struct_field("node", 0, |this| self.node.encode(this))
-//!                 .unwrap();
-//!             this.emit_struct_field("span", 1, |this| self.span.encode(this))
-//!         })
-//!     }
-//! }
-//!
-//! impl<
-//!     D: Decoder<E>,
-//!     E,
-//!     T: Decodable<D, E>
-//! > Decodable<D, E> for Spanned<T> {
-//!     fn decode(d: &mut D) -> Result<Spanned<T>, E> {
-//!         d.read_struct("Spanned", 2, |this| {
-//!             Ok(Spanned {
-//!                 node: this.read_struct_field("node", 0, |this| Decodable::decode(this))
-//!                     .unwrap(),
-//!                 span: this.read_struct_field("span", 1, |this| Decodable::decode(this))
-//!                     .unwrap(),
-//!             })
-//!         })
-//!     }
-//! }
-//! ```
-
-use rustc_ast::{AttrVec, ExprKind, MetaItem, Mutability};
-use rustc_expand::base::{Annotatable, ExtCtxt};
-use rustc_span::{Ident, Span, Symbol, sym};
-use thin_vec::{ThinVec, thin_vec};
-
-use crate::deriving::generic::ty::*;
-use crate::deriving::generic::*;
-use crate::deriving::pathvec_std;
-
-pub(crate) fn expand_deriving_rustc_encodable(
-    cx: &ExtCtxt<'_>,
-    span: Span,
-    mitem: &MetaItem,
-    item: &Annotatable,
-    push: &mut dyn FnMut(Annotatable),
-    is_const: bool,
-) {
-    let krate = sym::rustc_serialize;
-    let typaram = sym::__S;
-
-    let trait_def = TraitDef {
-        span,
-        path: Path::new_(vec![krate, sym::Encodable], vec![], PathKind::Global),
-        skip_path_as_bound: false,
-        needs_copy_as_bound_if_packed: true,
-        additional_bounds: Vec::new(),
-        supports_unions: false,
-        methods: vec![MethodDef {
-            name: sym::encode,
-            generics: Bounds {
-                bounds: vec![(typaram, vec![Path::new_(
-                    vec![krate, sym::Encoder],
-                    vec![],
-                    PathKind::Global,
-                )])],
-            },
-            explicit_self: true,
-            nonself_args: vec![(
-                Ref(Box::new(Path(Path::new_local(typaram))), Mutability::Mut),
-                sym::s,
-            )],
-            ret_ty: Path(Path::new_(
-                pathvec_std!(result::Result),
-                vec![
-                    Box::new(Unit),
-                    Box::new(Path(Path::new_(vec![typaram, sym::Error], vec![], PathKind::Local))),
-                ],
-                PathKind::Std,
-            )),
-            attributes: AttrVec::new(),
-            fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
-            combine_substructure: combine_substructure(Box::new(|a, b, c| {
-                encodable_substructure(a, b, c, krate)
-            })),
-        }],
-        associated_types: Vec::new(),
-        is_const,
-    };
-
-    trait_def.expand(cx, mitem, item, push)
-}
-
-fn encodable_substructure(
-    cx: &ExtCtxt<'_>,
-    trait_span: Span,
-    substr: &Substructure<'_>,
-    krate: Symbol,
-) -> BlockOrExpr {
-    let encoder = substr.nonselflike_args[0].clone();
-    // throw an underscore in front to suppress unused variable warnings
-    let blkarg = Ident::new(sym::_e, trait_span);
-    let blkencoder = cx.expr_ident(trait_span, blkarg);
-    let fn_path = cx.expr_path(cx.path_global(trait_span, vec![
-        Ident::new(krate, trait_span),
-        Ident::new(sym::Encodable, trait_span),
-        Ident::new(sym::encode, trait_span),
-    ]));
-
-    match substr.fields {
-        Struct(_, fields) => {
-            let fn_emit_struct_field_path =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Encoder, sym::emit_struct_field]);
-            let mut stmts = ThinVec::new();
-            for (i, &FieldInfo { name, ref self_expr, span, .. }) in fields.iter().enumerate() {
-                let name = match name {
-                    Some(id) => id.name,
-                    None => Symbol::intern(&format!("_field{i}")),
-                };
-                let self_ref = cx.expr_addr_of(span, self_expr.clone());
-                let enc =
-                    cx.expr_call(span, fn_path.clone(), thin_vec![self_ref, blkencoder.clone()]);
-                let lambda = cx.lambda1(span, enc, blkarg);
-                let call = cx.expr_call_global(span, fn_emit_struct_field_path.clone(), thin_vec![
-                    blkencoder.clone(),
-                    cx.expr_str(span, name),
-                    cx.expr_usize(span, i),
-                    lambda,
-                ]);
-
-                // last call doesn't need a try!
-                let last = fields.len() - 1;
-                let call = if i != last {
-                    cx.expr_try(span, call)
-                } else {
-                    cx.expr(span, ExprKind::Ret(Some(call)))
-                };
-
-                let stmt = cx.stmt_expr(call);
-                stmts.push(stmt);
-            }
-
-            // unit structs have no fields and need to return Ok()
-            let blk = if stmts.is_empty() {
-                let ok = cx.expr_ok(trait_span, cx.expr_tuple(trait_span, ThinVec::new()));
-                cx.lambda1(trait_span, ok, blkarg)
-            } else {
-                cx.lambda_stmts_1(trait_span, stmts, blkarg)
-            };
-
-            let fn_emit_struct_path =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Encoder, sym::emit_struct]);
-
-            let expr = cx.expr_call_global(trait_span, fn_emit_struct_path, thin_vec![
-                encoder,
-                cx.expr_str(trait_span, substr.type_ident.name),
-                cx.expr_usize(trait_span, fields.len()),
-                blk,
-            ]);
-            BlockOrExpr::new_expr(expr)
-        }
-
-        EnumMatching(idx, variant, fields) => {
-            // We're not generating an AST that the borrow checker is expecting,
-            // so we need to generate a unique local variable to take the
-            // mutable loan out on, otherwise we get conflicts which don't
-            // actually exist.
-            let me = cx.stmt_let(trait_span, false, blkarg, encoder);
-            let encoder = cx.expr_ident(trait_span, blkarg);
-
-            let fn_emit_enum_variant_arg_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Encoder, sym::emit_enum_variant_arg]);
-
-            let mut stmts = ThinVec::new();
-            if !fields.is_empty() {
-                let last = fields.len() - 1;
-                for (i, &FieldInfo { ref self_expr, span, .. }) in fields.iter().enumerate() {
-                    let self_ref = cx.expr_addr_of(span, self_expr.clone());
-                    let enc = cx
-                        .expr_call(span, fn_path.clone(), thin_vec![self_ref, blkencoder.clone()]);
-                    let lambda = cx.lambda1(span, enc, blkarg);
-
-                    let call = cx.expr_call_global(
-                        span,
-                        fn_emit_enum_variant_arg_path.clone(),
-                        thin_vec![blkencoder.clone(), cx.expr_usize(span, i), lambda],
-                    );
-                    let call = if i != last {
-                        cx.expr_try(span, call)
-                    } else {
-                        cx.expr(span, ExprKind::Ret(Some(call)))
-                    };
-                    stmts.push(cx.stmt_expr(call));
-                }
-            } else {
-                let ok = cx.expr_ok(trait_span, cx.expr_tuple(trait_span, ThinVec::new()));
-                let ret_ok = cx.expr(trait_span, ExprKind::Ret(Some(ok)));
-                stmts.push(cx.stmt_expr(ret_ok));
-            }
-
-            let blk = cx.lambda_stmts_1(trait_span, stmts, blkarg);
-            let name = cx.expr_str(trait_span, variant.ident.name);
-
-            let fn_emit_enum_variant_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Encoder, sym::emit_enum_variant]);
-
-            let call = cx.expr_call_global(trait_span, fn_emit_enum_variant_path, thin_vec![
-                blkencoder,
-                name,
-                cx.expr_usize(trait_span, *idx),
-                cx.expr_usize(trait_span, fields.len()),
-                blk,
-            ]);
-
-            let blk = cx.lambda1(trait_span, call, blkarg);
-            let fn_emit_enum_path: Vec<_> =
-                cx.def_site_path(&[sym::rustc_serialize, sym::Encoder, sym::emit_enum]);
-            let expr = cx.expr_call_global(trait_span, fn_emit_enum_path, thin_vec![
-                encoder,
-                cx.expr_str(trait_span, substr.type_ident.name),
-                blk
-            ]);
-            BlockOrExpr::new_mixed(thin_vec![me], Some(expr))
-        }
-
-        _ => cx.dcx().bug("expected Struct or EnumMatching in derive(Encodable)"),
-    }
-}
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
index f0a5e44e066ee..755a733286cea 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
@@ -311,7 +311,7 @@ pub(crate) enum SubstructureFields<'a> {
     /// Matching variants of the enum: variant index, ast::Variant,
     /// fields: the field name is only non-`None` in the case of a struct
     /// variant.
-    EnumMatching(usize, &'a ast::Variant, Vec<FieldInfo>),
+    EnumMatching(&'a ast::Variant, Vec<FieldInfo>),
 
     /// The discriminant of an enum. The first field is a `FieldInfo` for the discriminants, as
     /// if they were fields. The second field is the expression to combine the
@@ -322,7 +322,7 @@ pub(crate) enum SubstructureFields<'a> {
     StaticStruct(&'a ast::VariantData, StaticFields),
 
     /// A static method where `Self` is an enum.
-    StaticEnum(&'a ast::EnumDef, Vec<(Ident, Span, StaticFields)>),
+    StaticEnum(&'a ast::EnumDef),
 }
 
 /// Combine the values of all the fields together. The last argument is
@@ -1270,7 +1270,7 @@ impl<'a> MethodDef<'a> {
                     trait_,
                     type_ident,
                     nonselflike_args,
-                    &EnumMatching(0, variant, Vec::new()),
+                    &EnumMatching(variant, Vec::new()),
                 );
             }
         }
@@ -1282,9 +1282,8 @@ impl<'a> MethodDef<'a> {
         // where each tuple has length = selflike_args.len()
         let mut match_arms: ThinVec<ast::Arm> = variants
             .iter()
-            .enumerate()
-            .filter(|&(_, v)| !(unify_fieldless_variants && v.data.fields().is_empty()))
-            .map(|(index, variant)| {
+            .filter(|&v| !(unify_fieldless_variants && v.data.fields().is_empty()))
+            .map(|variant| {
                 // A single arm has form (&VariantK, &VariantK, ...) => BodyK
                 // (see "Final wrinkle" note below for why.)
 
@@ -1316,7 +1315,7 @@ impl<'a> MethodDef<'a> {
                 // expressions for referencing every field of every
                 // Self arg, assuming all are instances of VariantK.
                 // Build up code associated with such a case.
-                let substructure = EnumMatching(index, variant, fields);
+                let substructure = EnumMatching(variant, fields);
                 let arm_expr = self
                     .call_substructure_method(
                         cx,
@@ -1344,7 +1343,7 @@ impl<'a> MethodDef<'a> {
                         trait_,
                         type_ident,
                         nonselflike_args,
-                        &EnumMatching(0, v, Vec::new()),
+                        &EnumMatching(v, Vec::new()),
                     )
                     .into_expr(cx, span),
                 )
@@ -1407,21 +1406,12 @@ impl<'a> MethodDef<'a> {
         type_ident: Ident,
         nonselflike_args: &[P<Expr>],
     ) -> BlockOrExpr {
-        let summary = enum_def
-            .variants
-            .iter()
-            .map(|v| {
-                let sp = v.span.with_ctxt(trait_.span.ctxt());
-                let summary = trait_.summarise_struct(cx, &v.data);
-                (v.ident, sp, summary)
-            })
-            .collect();
         self.call_substructure_method(
             cx,
             trait_,
             type_ident,
             nonselflike_args,
-            &StaticEnum(enum_def, summary),
+            &StaticEnum(enum_def),
         )
     }
 }
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs b/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs
index af6dc62db7a90..f34a6ae1d9829 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs
@@ -21,7 +21,6 @@ pub(crate) struct Path {
 #[derive(Clone)]
 pub(crate) enum PathKind {
     Local,
-    Global,
     Std,
 }
 
@@ -57,7 +56,6 @@ impl Path {
         let params = tys.map(GenericArg::Type).collect();
 
         match self.kind {
-            PathKind::Global => cx.path_all(span, true, idents, params),
             PathKind::Local => cx.path_all(span, false, idents, params),
             PathKind::Std => {
                 let def_site = cx.with_def_site_ctxt(DUMMY_SP);
diff --git a/compiler/rustc_builtin_macros/src/deriving/mod.rs b/compiler/rustc_builtin_macros/src/deriving/mod.rs
index ec058b4131376..c112589b1319d 100644
--- a/compiler/rustc_builtin_macros/src/deriving/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/mod.rs
@@ -23,9 +23,7 @@ pub(crate) mod bounds;
 pub(crate) mod clone;
 pub(crate) mod coerce_pointee;
 pub(crate) mod debug;
-pub(crate) mod decodable;
 pub(crate) mod default;
-pub(crate) mod encodable;
 pub(crate) mod hash;
 
 #[path = "cmp/eq.rs"]
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index 0918403b8555a..6987ae95980a6 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -132,8 +132,6 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
         Ord: ord::expand_deriving_ord,
         PartialEq: partial_eq::expand_deriving_partial_eq,
         PartialOrd: partial_ord::expand_deriving_partial_ord,
-        RustcDecodable: decodable::expand_deriving_rustc_decodable,
-        RustcEncodable: encodable::expand_deriving_rustc_encodable,
         CoercePointee: coerce_pointee::expand_deriving_coerce_pointee,
     }
 
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index b96df81485294..29a74ed3f4e48 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -644,7 +644,14 @@ impl<'a, G: EmissionGuarantee> Diag<'a, G> {
         found_label: &dyn fmt::Display,
         found: DiagStyledString,
     ) -> &mut Self {
-        self.note_expected_found_extra(expected_label, expected, found_label, found, &"", &"")
+        self.note_expected_found_extra(
+            expected_label,
+            expected,
+            found_label,
+            found,
+            DiagStyledString::normal(""),
+            DiagStyledString::normal(""),
+        )
     }
 
     #[rustc_lint_diagnostics]
@@ -654,8 +661,8 @@ impl<'a, G: EmissionGuarantee> Diag<'a, G> {
         expected: DiagStyledString,
         found_label: &dyn fmt::Display,
         found: DiagStyledString,
-        expected_extra: &dyn fmt::Display,
-        found_extra: &dyn fmt::Display,
+        expected_extra: DiagStyledString,
+        found_extra: DiagStyledString,
     ) -> &mut Self {
         let expected_label = expected_label.to_string();
         let expected_label = if expected_label.is_empty() {
@@ -680,10 +687,13 @@ impl<'a, G: EmissionGuarantee> Diag<'a, G> {
             expected_label
         ))];
         msg.extend(expected.0);
-        msg.push(StringPart::normal(format!("`{expected_extra}\n")));
+        msg.push(StringPart::normal(format!("`")));
+        msg.extend(expected_extra.0);
+        msg.push(StringPart::normal(format!("\n")));
         msg.push(StringPart::normal(format!("{}{} `", " ".repeat(found_padding), found_label)));
         msg.extend(found.0);
-        msg.push(StringPart::normal(format!("`{found_extra}")));
+        msg.push(StringPart::normal(format!("`")));
+        msg.extend(found_extra.0);
 
         // For now, just attach these as notes.
         self.highlighted_note(msg);
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index 684fc5e37e0bb..e0543977e98d8 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -616,7 +616,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         EncodeCrossCrate::No, "allow_internal_unsafe side-steps the unsafe_code lint",
     ),
     rustc_attr!(
-        rustc_allowed_through_unstable_modules, Normal, template!(Word, NameValueStr: "deprecation message"),
+        rustc_allowed_through_unstable_modules, Normal, template!(NameValueStr: "deprecation message"),
         WarnFollowing, EncodeCrossCrate::No,
         "rustc_allowed_through_unstable_modules special cases accidental stabilizations of stable items \
         through unstable paths"
diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs
index 153fd6001bbc8..83acc7dd6afc5 100644
--- a/compiler/rustc_hir_typeck/src/coercion.rs
+++ b/compiler/rustc_hir_typeck/src/coercion.rs
@@ -50,7 +50,6 @@ use rustc_infer::traits::{
     IfExpressionCause, MatchExpressionArmCause, Obligation, PredicateObligation,
     PredicateObligations,
 };
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::span_bug;
 use rustc_middle::traits::BuiltinImplSource;
 use rustc_middle::ty::adjustment::{
@@ -1937,7 +1936,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
                     cond_expr.span.desugaring_kind(),
                     None | Some(DesugaringKind::WhileLoop)
                 )
-                && !in_external_macro(fcx.tcx.sess, cond_expr.span)
+                && !cond_expr.span.in_external_macro(fcx.tcx.sess.source_map())
                 && !matches!(
                     cond_expr.kind,
                     hir::ExprKind::Match(.., hir::MatchSource::TryDesugar(_))
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index beddbf971fd3e..217ebd9cd2bf4 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -14,7 +14,6 @@ use rustc_hir::{
 };
 use rustc_hir_analysis::hir_ty_lowering::HirTyLowerer;
 use rustc_hir_analysis::suggest_impl_trait;
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::span_bug;
 use rustc_middle::ty::print::with_no_trimmed_paths;
@@ -770,7 +769,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         // If the expression is from an external macro, then do not suggest
                         // adding a semicolon, because there's nowhere to put it.
                         // See issue #81943.
-                        && !in_external_macro(self.tcx.sess, expression.span) =>
+                        && !expression.span.in_external_macro(self.tcx.sess.source_map()) =>
                 {
                     if needs_block {
                         err.multipart_suggestion(
@@ -2261,7 +2260,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Ty<'tcx>,
         expr_ty: Ty<'tcx>,
     ) -> bool {
-        if in_external_macro(self.tcx.sess, expr.span) {
+        if expr.span.in_external_macro(self.tcx.sess.source_map()) {
             return false;
         }
         if let ty::Adt(expected_adt, args) = expected.kind() {
@@ -2589,14 +2588,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     )> {
         let sess = self.sess();
         let sp = expr.span;
+        let sm = sess.source_map();
 
         // If the span is from an external macro, there's no suggestion we can make.
-        if in_external_macro(sess, sp) {
+        if sp.in_external_macro(sm) {
             return None;
         }
 
-        let sm = sess.source_map();
-
         let replace_prefix = |s: &str, old: &str, new: &str| {
             s.strip_prefix(old).map(|stripped| new.to_string() + stripped)
         };
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index e8a4e9a84c467..e2bafbed6e123 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -29,7 +29,6 @@ use rustc_hir::def_id::{CRATE_DEF_ID, DefId, LocalDefId};
 use rustc_hir::intravisit::FnKind as HirFnKind;
 use rustc_hir::{Body, FnDecl, GenericParamKind, PatKind, PredicateOrigin};
 use rustc_middle::bug;
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt, Upcast, VariantDef};
@@ -2029,7 +2028,7 @@ impl ExplicitOutlivesRequirements {
                 }
 
                 let span = bound.span().find_ancestor_inside(predicate_span)?;
-                if in_external_macro(tcx.sess, span) {
+                if span.in_external_macro(tcx.sess.source_map()) {
                     return None;
                 }
 
diff --git a/compiler/rustc_lint/src/early/diagnostics/check_cfg.rs b/compiler/rustc_lint/src/early/diagnostics/check_cfg.rs
index da6dd8161ee58..946dbc34f7138 100644
--- a/compiler/rustc_lint/src/early/diagnostics/check_cfg.rs
+++ b/compiler/rustc_lint/src/early/diagnostics/check_cfg.rs
@@ -135,7 +135,7 @@ pub(super) fn unexpected_cfg_name(
     };
 
     let is_from_cargo = rustc_session::utils::was_invoked_from_cargo();
-    let is_from_external_macro = rustc_middle::lint::in_external_macro(sess, name_span);
+    let is_from_external_macro = name_span.in_external_macro(sess.source_map());
     let mut is_feature_cfg = name == sym::feature;
 
     let code_sugg = if is_feature_cfg && is_from_cargo {
@@ -281,7 +281,7 @@ pub(super) fn unexpected_cfg_value(
         .collect();
 
     let is_from_cargo = rustc_session::utils::was_invoked_from_cargo();
-    let is_from_external_macro = rustc_middle::lint::in_external_macro(sess, name_span);
+    let is_from_external_macro = name_span.in_external_macro(sess.source_map());
 
     // Show the full list if all possible values for a given name, but don't do it
     // for names as the possibilities could be very long
diff --git a/compiler/rustc_lint/src/non_fmt_panic.rs b/compiler/rustc_lint/src/non_fmt_panic.rs
index 6f047b4da4954..648d06756275f 100644
--- a/compiler/rustc_lint/src/non_fmt_panic.rs
+++ b/compiler/rustc_lint/src/non_fmt_panic.rs
@@ -2,7 +2,6 @@ use rustc_ast as ast;
 use rustc_errors::Applicability;
 use rustc_hir::{self as hir, LangItem};
 use rustc_infer::infer::TyCtxtInferExt;
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::{bug, ty};
 use rustc_parse_format::{ParseMode, Parser, Piece};
 use rustc_session::lint::FutureIncompatibilityReason;
@@ -100,7 +99,7 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
 
     let (span, panic, symbol) = panic_call(cx, f);
 
-    if in_external_macro(cx.sess(), span) {
+    if span.in_external_macro(cx.sess().source_map()) {
         // Nothing that can be done about it in the current crate.
         return;
     }
@@ -229,14 +228,15 @@ fn check_panic_str<'tcx>(
 
     let (span, _, _) = panic_call(cx, f);
 
-    if in_external_macro(cx.sess(), span) && in_external_macro(cx.sess(), arg.span) {
+    let sm = cx.sess().source_map();
+    if span.in_external_macro(sm) && arg.span.in_external_macro(sm) {
         // Nothing that can be done about it in the current crate.
         return;
     }
 
     let fmt_span = arg.span.source_callsite();
 
-    let (snippet, style) = match cx.sess().psess.source_map().span_to_snippet(fmt_span) {
+    let (snippet, style) = match sm.span_to_snippet(fmt_span) {
         Ok(snippet) => {
             // Count the number of `#`s between the `r` and `"`.
             let style = snippet.strip_prefix('r').and_then(|s| s.find('"'));
@@ -283,7 +283,7 @@ fn check_panic_str<'tcx>(
 /// Given the span of `some_macro!(args);`, gives the span of `(` and `)`,
 /// and the type of (opening) delimiter used.
 fn find_delimiters(cx: &LateContext<'_>, span: Span) -> Option<(Span, Span, char)> {
-    let snippet = cx.sess().psess.source_map().span_to_snippet(span).ok()?;
+    let snippet = cx.sess().source_map().span_to_snippet(span).ok()?;
     let (open, open_ch) = snippet.char_indices().find(|&(_, c)| "([{".contains(c))?;
     let close = snippet.rfind(|c| ")]}".contains(c))?;
     Some((
diff --git a/compiler/rustc_middle/src/lint.rs b/compiler/rustc_middle/src/lint.rs
index cae980cde613f..ab711aca573e5 100644
--- a/compiler/rustc_middle/src/lint.rs
+++ b/compiler/rustc_middle/src/lint.rs
@@ -8,8 +8,7 @@ use rustc_macros::{Decodable, Encodable, HashStable};
 use rustc_session::Session;
 use rustc_session::lint::builtin::{self, FORBIDDEN_LINT_GROUPS};
 use rustc_session::lint::{FutureIncompatibilityReason, Level, Lint, LintExpectationId, LintId};
-use rustc_span::hygiene::{ExpnKind, MacroKind};
-use rustc_span::{DUMMY_SP, DesugaringKind, Span, Symbol, kw};
+use rustc_span::{DUMMY_SP, Span, Symbol, kw};
 use tracing::instrument;
 
 use crate::ty::TyCtxt;
@@ -201,7 +200,7 @@ impl LintExpectation {
     }
 }
 
-pub fn explain_lint_level_source(
+fn explain_lint_level_source(
     lint: &'static Lint,
     level: Level,
     src: LintLevelSource,
@@ -325,7 +324,7 @@ pub fn lint_level(
         // If this code originates in a foreign macro, aka something that this crate
         // did not itself author, then it's likely that there's nothing this crate
         // can do about it. We probably want to skip the lint entirely.
-        if err.span.primary_spans().iter().any(|s| in_external_macro(sess, *s)) {
+        if err.span.primary_spans().iter().any(|s| s.in_external_macro(sess.source_map())) {
             // Any suggestions made here are likely to be incorrect, so anything we
             // emit shouldn't be automatically fixed by rustfix.
             err.disable_suggestions();
@@ -422,36 +421,3 @@ pub fn lint_level(
     }
     lint_level_impl(sess, lint, level, src, span, Box::new(decorate))
 }
-
-/// Returns whether `span` originates in a foreign crate's external macro.
-///
-/// This is used to test whether a lint should not even begin to figure out whether it should
-/// be reported on the current node.
-pub fn in_external_macro(sess: &Session, span: Span) -> bool {
-    let expn_data = span.ctxt().outer_expn_data();
-    match expn_data.kind {
-        ExpnKind::Root
-        | ExpnKind::Desugaring(
-            DesugaringKind::ForLoop
-            | DesugaringKind::WhileLoop
-            | DesugaringKind::OpaqueTy
-            | DesugaringKind::Async
-            | DesugaringKind::Await,
-        ) => false,
-        ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external"
-        ExpnKind::Macro(MacroKind::Bang, _) => {
-            // Dummy span for the `def_site` means it's an external macro.
-            expn_data.def_site.is_dummy() || sess.source_map().is_imported(expn_data.def_site)
-        }
-        ExpnKind::Macro { .. } => true, // definitely a plugin
-    }
-}
-
-/// Return whether `span` is generated by `async` or `await`.
-pub fn is_from_async_await(span: Span) -> bool {
-    let expn_data = span.ctxt().outer_expn_data();
-    match expn_data.kind {
-        ExpnKind::Desugaring(DesugaringKind::Async | DesugaringKind::Await) => true,
-        _ => false,
-    }
-}
diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs
index e49fc376a13cd..75931956310cd 100644
--- a/compiler/rustc_middle/src/mir/mono.rs
+++ b/compiler/rustc_middle/src/mir/mono.rs
@@ -92,51 +92,88 @@ impl<'tcx> MonoItem<'tcx> {
     }
 
     pub fn instantiation_mode(&self, tcx: TyCtxt<'tcx>) -> InstantiationMode {
-        let generate_cgu_internal_copies =
-            (tcx.sess.opts.optimize != OptLevel::No) && !tcx.sess.link_dead_code();
+        // The case handling here is written in the same style as cross_crate_inlinable, we first
+        // handle the cases where we must use a particular instantiation mode, then cascade down
+        // through a sequence of heuristics.
 
-        match *self {
-            MonoItem::Fn(ref instance) => {
-                let entry_def_id = tcx.entry_fn(()).map(|(id, _)| id);
-                // If this function isn't inlined or otherwise has an extern
-                // indicator, then we'll be creating a globally shared version.
-                let codegen_fn_attrs = tcx.codegen_fn_attrs(instance.def_id());
-                if codegen_fn_attrs.contains_extern_indicator()
-                    || codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED)
-                    || !instance.def.generates_cgu_internal_copy(tcx)
-                    || Some(instance.def_id()) == entry_def_id
-                {
-                    return InstantiationMode::GloballyShared { may_conflict: false };
-                }
-
-                if let InlineAttr::Never = tcx.codegen_fn_attrs(instance.def_id()).inline
-                    && self.is_generic_fn()
-                {
-                    // Upgrade inline(never) to a globally shared instance.
-                    return InstantiationMode::GloballyShared { may_conflict: true };
-                }
-
-                // At this point we don't have explicit linkage and we're an
-                // inlined function. If this crate's build settings permit,
-                // we'll be creating a local copy per CGU.
-                if generate_cgu_internal_copies {
-                    return InstantiationMode::LocalCopy;
-                }
-
-                // Finally, if this is `#[inline(always)]` we're sure to respect
-                // that with an inline copy per CGU, but otherwise we'll be
-                // creating one copy of this `#[inline]` function which may
-                // conflict with upstream crates as it could be an exported
-                // symbol.
-                if tcx.codegen_fn_attrs(instance.def_id()).inline.always() {
-                    InstantiationMode::LocalCopy
-                } else {
-                    InstantiationMode::GloballyShared { may_conflict: true }
-                }
-            }
+        // The first thing we do is detect MonoItems which we must instantiate exactly once in the
+        // whole program.
+
+        // Statics and global_asm! must be instantiated exactly once.
+        let instance = match *self {
+            MonoItem::Fn(instance) => instance,
             MonoItem::Static(..) | MonoItem::GlobalAsm(..) => {
-                InstantiationMode::GloballyShared { may_conflict: false }
+                return InstantiationMode::GloballyShared { may_conflict: false };
             }
+        };
+
+        // Similarly, the executable entrypoint must be instantiated exactly once.
+        if let Some((entry_def_id, _)) = tcx.entry_fn(()) {
+            if instance.def_id() == entry_def_id {
+                return InstantiationMode::GloballyShared { may_conflict: false };
+            }
+        }
+
+        // If the function is #[naked] or contains any other attribute that requires exactly-once
+        // instantiation:
+        let codegen_fn_attrs = tcx.codegen_fn_attrs(instance.def_id());
+        if codegen_fn_attrs.contains_extern_indicator()
+            || codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED)
+        {
+            return InstantiationMode::GloballyShared { may_conflict: false };
+        }
+
+        // FIXME: The logic for which functions are permitted to get LocalCopy is actually spread
+        // across 4 functions:
+        // * cross_crate_inlinable(def_id)
+        // * InstanceKind::requires_inline
+        // * InstanceKind::generate_cgu_internal_copy
+        // * MonoItem::instantiation_mode
+        // Since reachable_non_generics calls InstanceKind::generates_cgu_internal_copy to decide
+        // which symbols this crate exports, we are obligated to only generate LocalCopy when
+        // generates_cgu_internal_copy returns true.
+        if !instance.def.generates_cgu_internal_copy(tcx) {
+            return InstantiationMode::GloballyShared { may_conflict: false };
+        }
+
+        // Beginning of heuristics. The handling of link-dead-code and inline(always) are QoL only,
+        // the compiler should not crash and linkage should work, but codegen may be undesirable.
+
+        // -Clink-dead-code was given an unfortunate name; the point of the flag is to assist
+        // coverage tools which rely on having every function in the program appear in the
+        // generated code. If we select LocalCopy, functions which are not used because they are
+        // missing test coverage will disappear from such coverage reports, defeating the point.
+        // Note that -Cinstrument-coverage does not require such assistance from us, only coverage
+        // tools implemented without compiler support ironically require a special compiler flag.
+        if tcx.sess.link_dead_code() {
+            return InstantiationMode::GloballyShared { may_conflict: true };
+        }
+
+        // To ensure that #[inline(always)] can be inlined as much as possible, especially in unoptimized
+        // builds, we always select LocalCopy.
+        if codegen_fn_attrs.inline.always() {
+            return InstantiationMode::LocalCopy;
+        }
+
+        // #[inline(never)] functions in general are poor candidates for inlining and thus since
+        // LocalCopy generally increases code size for the benefit of optimizations from inlining,
+        // we want to give them GloballyShared codegen.
+        // The slight problem is that generic functions need to always support cross-crate
+        // compilation, so all previous stages of the compiler are obligated to treat generic
+        // functions the same as those that unconditionally get LocalCopy codegen. It's only when
+        // we get here that we can at least not codegen a #[inline(never)] generic function in all
+        // of our CGUs.
+        if let InlineAttr::Never = tcx.codegen_fn_attrs(instance.def_id()).inline
+            && self.is_generic_fn()
+        {
+            return InstantiationMode::GloballyShared { may_conflict: true };
+        }
+
+        // The fallthrough case is to generate LocalCopy for all optimized builds, and
+        // GloballyShared with conflict prevention when optimizations are disabled.
+        match tcx.sess.opts.optimize {
+            OptLevel::No => InstantiationMode::GloballyShared { may_conflict: true },
+            _ => InstantiationMode::LocalCopy,
         }
     }
 
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index a52f080038d1d..34f1ca55c7875 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -5,8 +5,8 @@ use std::mem::replace;
 use std::num::NonZero;
 
 use rustc_attr_parsing::{
-    self as attr, AllowedThroughUnstableModules, ConstStability, DeprecatedSince, Stability,
-    StabilityLevel, StableSince, UnstableReason, VERSION_PLACEHOLDER,
+    self as attr, ConstStability, DeprecatedSince, Stability, StabilityLevel, StableSince,
+    UnstableReason, VERSION_PLACEHOLDER,
 };
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::unord::{ExtendUnord, UnordMap, UnordSet};
@@ -880,7 +880,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
 
             if item_is_allowed {
                 // The item itself is allowed; check whether the path there is also allowed.
-                let is_allowed_through_unstable_modules: Option<AllowedThroughUnstableModules> =
+                let is_allowed_through_unstable_modules: Option<Symbol> =
                     self.tcx.lookup_stability(def_id).and_then(|stab| match stab.level {
                         StabilityLevel::Stable { allowed_through_unstable_modules, .. } => {
                             allowed_through_unstable_modules
@@ -888,83 +888,79 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
                         _ => None,
                     });
 
-                if is_allowed_through_unstable_modules.is_none() {
-                    // Check parent modules stability as well if the item the path refers to is itself
-                    // stable. We only emit warnings for unstable path segments if the item is stable
-                    // or allowed because stability is often inherited, so the most common case is that
-                    // both the segments and the item are unstable behind the same feature flag.
-                    //
-                    // We check here rather than in `visit_path_segment` to prevent visiting the last
-                    // path segment twice
-                    //
-                    // We include special cases via #[rustc_allowed_through_unstable_modules] for items
-                    // that were accidentally stabilized through unstable paths before this check was
-                    // added, such as `core::intrinsics::transmute`
-                    let parents = path.segments.iter().rev().skip(1);
-                    for path_segment in parents {
-                        if let Some(def_id) = path_segment.res.opt_def_id() {
-                            // use `None` for id to prevent deprecation check
-                            self.tcx.check_stability_allow_unstable(
-                                def_id,
-                                None,
-                                path.span,
-                                None,
-                                if is_unstable_reexport(self.tcx, id) {
-                                    AllowUnstable::Yes
-                                } else {
-                                    AllowUnstable::No
-                                },
-                            );
-                        }
-                    }
-                } else if let Some(AllowedThroughUnstableModules::WithDeprecation(deprecation)) =
-                    is_allowed_through_unstable_modules
-                {
-                    // Similar to above, but we cannot use `check_stability_allow_unstable` as that would
-                    // immediately show the stability error. We just want to know the result and disaplay
-                    // our own kind of error.
-                    let parents = path.segments.iter().rev().skip(1);
-                    for path_segment in parents {
-                        if let Some(def_id) = path_segment.res.opt_def_id() {
-                            // use `None` for id to prevent deprecation check
-                            let eval_result = self.tcx.eval_stability_allow_unstable(
-                                def_id,
-                                None,
-                                path.span,
-                                None,
-                                if is_unstable_reexport(self.tcx, id) {
-                                    AllowUnstable::Yes
-                                } else {
-                                    AllowUnstable::No
-                                },
-                            );
-                            let is_allowed = matches!(eval_result, EvalResult::Allow);
-                            if !is_allowed {
-                                // Calculating message for lint involves calling `self.def_path_str`,
-                                // which will by default invoke the expensive `visible_parent_map` query.
-                                // Skip all that work if the lint is allowed anyway.
-                                if self.tcx.lint_level_at_node(DEPRECATED, id).0
-                                    == lint::Level::Allow
-                                {
-                                    return;
-                                }
-                                // Show a deprecation message.
-                                let def_path =
-                                    with_no_trimmed_paths!(self.tcx.def_path_str(def_id));
-                                let def_kind = self.tcx.def_descr(def_id);
-                                let diag = Deprecated {
-                                    sub: None,
-                                    kind: def_kind.to_owned(),
-                                    path: def_path,
-                                    note: Some(deprecation),
-                                    since_kind: lint::DeprecatedSinceKind::InEffect,
-                                };
-                                self.tcx.emit_node_span_lint(
-                                    DEPRECATED,
-                                    id,
-                                    method_span.unwrap_or(path.span),
-                                    diag,
+                // Check parent modules stability as well if the item the path refers to is itself
+                // stable. We only emit errors for unstable path segments if the item is stable
+                // or allowed because stability is often inherited, so the most common case is that
+                // both the segments and the item are unstable behind the same feature flag.
+                //
+                // We check here rather than in `visit_path_segment` to prevent visiting the last
+                // path segment twice
+                //
+                // We include special cases via #[rustc_allowed_through_unstable_modules] for items
+                // that were accidentally stabilized through unstable paths before this check was
+                // added, such as `core::intrinsics::transmute`
+                let parents = path.segments.iter().rev().skip(1);
+                for path_segment in parents {
+                    if let Some(def_id) = path_segment.res.opt_def_id() {
+                        match is_allowed_through_unstable_modules {
+                            None => {
+                                // Emit a hard stability error if this path is not stable.
+
+                                // use `None` for id to prevent deprecation check
+                                self.tcx.check_stability_allow_unstable(
+                                    def_id,
+                                    None,
+                                    path.span,
+                                    None,
+                                    if is_unstable_reexport(self.tcx, id) {
+                                        AllowUnstable::Yes
+                                    } else {
+                                        AllowUnstable::No
+                                    },
+                                );
+                            }
+                            Some(deprecation) => {
+                                // Call the stability check directly so that we can control which
+                                // diagnostic is emitted.
+                                let eval_result = self.tcx.eval_stability_allow_unstable(
+                                    def_id,
+                                    None,
+                                    path.span,
+                                    None,
+                                    if is_unstable_reexport(self.tcx, id) {
+                                        AllowUnstable::Yes
+                                    } else {
+                                        AllowUnstable::No
+                                    },
                                 );
+                                let is_allowed = matches!(eval_result, EvalResult::Allow);
+                                if !is_allowed {
+                                    // Calculating message for lint involves calling `self.def_path_str`,
+                                    // which will by default invoke the expensive `visible_parent_map` query.
+                                    // Skip all that work if the lint is allowed anyway.
+                                    if self.tcx.lint_level_at_node(DEPRECATED, id).0
+                                        == lint::Level::Allow
+                                    {
+                                        return;
+                                    }
+                                    // Show a deprecation message.
+                                    let def_path =
+                                        with_no_trimmed_paths!(self.tcx.def_path_str(def_id));
+                                    let def_kind = self.tcx.def_descr(def_id);
+                                    let diag = Deprecated {
+                                        sub: None,
+                                        kind: def_kind.to_owned(),
+                                        path: def_path,
+                                        note: Some(deprecation),
+                                        since_kind: lint::DeprecatedSinceKind::InEffect,
+                                    };
+                                    self.tcx.emit_node_span_lint(
+                                        DEPRECATED,
+                                        id,
+                                        method_span.unwrap_or(path.span),
+                                        diag,
+                                    );
+                                }
                             }
                         }
                     }
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 51d809bd65d45..b1f9f4a01c54b 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -600,11 +600,43 @@ impl Span {
         !self.is_dummy() && sm.is_span_accessible(self)
     }
 
+    /// Returns whether `span` originates in a foreign crate's external macro.
+    ///
+    /// This is used to test whether a lint should not even begin to figure out whether it should
+    /// be reported on the current node.
+    pub fn in_external_macro(self, sm: &SourceMap) -> bool {
+        let expn_data = self.ctxt().outer_expn_data();
+        match expn_data.kind {
+            ExpnKind::Root
+            | ExpnKind::Desugaring(
+                DesugaringKind::ForLoop
+                | DesugaringKind::WhileLoop
+                | DesugaringKind::OpaqueTy
+                | DesugaringKind::Async
+                | DesugaringKind::Await,
+            ) => false,
+            ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external"
+            ExpnKind::Macro(MacroKind::Bang, _) => {
+                // Dummy span for the `def_site` means it's an external macro.
+                expn_data.def_site.is_dummy() || sm.is_imported(expn_data.def_site)
+            }
+            ExpnKind::Macro { .. } => true, // definitely a plugin
+        }
+    }
+
     /// Returns `true` if `span` originates in a derive-macro's expansion.
     pub fn in_derive_expansion(self) -> bool {
         matches!(self.ctxt().outer_expn_data().kind, ExpnKind::Macro(MacroKind::Derive, _))
     }
 
+    /// Return whether `span` is generated by `async` or `await`.
+    pub fn is_from_async_await(self) -> bool {
+        matches!(
+            self.ctxt().outer_expn_data().kind,
+            ExpnKind::Desugaring(DesugaringKind::Async | DesugaringKind::Await),
+        )
+    }
+
     /// Gate suggestions that would not be appropriate in a context the user didn't write.
     pub fn can_be_used_for_suggestions(self) -> bool {
         !self.from_expansion()
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 322da9390113d..b23cc90991154 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -314,8 +314,6 @@ symbols! {
         Right,
         Rust,
         RustaceansAreAwesome,
-        RustcDecodable,
-        RustcEncodable,
         RwLock,
         RwLockReadGuard,
         RwLockWriteGuard,
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
index ac72774027cff..091773009e98d 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
@@ -1722,32 +1722,42 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     }
                 }
                 TypeError::Sorts(values) => {
-                    let extra = expected == found;
+                    let extra = expected == found
+                        // Ensure that we don't ever say something like
+                        // expected `impl Trait` (opaque type `impl Trait`)
+                        //    found `impl Trait` (opaque type `impl Trait`)
+                        && values.expected.sort_string(self.tcx)
+                            != values.found.sort_string(self.tcx);
                     let sort_string = |ty: Ty<'tcx>| match (extra, ty.kind()) {
                         (true, ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. })) => {
                             let sm = self.tcx.sess.source_map();
                             let pos = sm.lookup_char_pos(self.tcx.def_span(*def_id).lo());
-                            format!(
+                            DiagStyledString::normal(format!(
                                 " (opaque type at <{}:{}:{}>)",
                                 sm.filename_for_diagnostics(&pos.file.name),
                                 pos.line,
                                 pos.col.to_usize() + 1,
-                            )
+                            ))
                         }
                         (true, ty::Alias(ty::Projection, proj))
                             if self.tcx.is_impl_trait_in_trait(proj.def_id) =>
                         {
                             let sm = self.tcx.sess.source_map();
                             let pos = sm.lookup_char_pos(self.tcx.def_span(proj.def_id).lo());
-                            format!(
+                            DiagStyledString::normal(format!(
                                 " (trait associated opaque type at <{}:{}:{}>)",
                                 sm.filename_for_diagnostics(&pos.file.name),
                                 pos.line,
                                 pos.col.to_usize() + 1,
-                            )
+                            ))
                         }
-                        (true, _) => format!(" ({})", ty.sort_string(self.tcx)),
-                        (false, _) => "".to_string(),
+                        (true, _) => {
+                            let mut s = DiagStyledString::normal(" (");
+                            s.push_highlighted(ty.sort_string(self.tcx));
+                            s.push_normal(")");
+                            s
+                        }
+                        (false, _) => DiagStyledString::normal(""),
                     };
                     if !(values.expected.is_simple_text() && values.found.is_simple_text())
                         || (exp_found.is_some_and(|ef| {
@@ -1764,23 +1774,23 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             }
                         }))
                     {
-                        if let Some(ExpectedFound { found: found_ty, .. }) = exp_found {
+                        if let Some(ExpectedFound { found: found_ty, .. }) = exp_found
+                            && !self.tcx.ty_is_opaque_future(found_ty)
+                        {
                             // `Future` is a special opaque type that the compiler
                             // will try to hide in some case such as `async fn`, so
                             // to make an error more use friendly we will
                             // avoid to suggest a mismatch type with a
                             // type that the user usually are not using
                             // directly such as `impl Future<Output = u8>`.
-                            if !self.tcx.ty_is_opaque_future(found_ty) {
-                                diag.note_expected_found_extra(
-                                    &expected_label,
-                                    expected,
-                                    &found_label,
-                                    found,
-                                    &sort_string(values.expected),
-                                    &sort_string(values.found),
-                                );
-                            }
+                            diag.note_expected_found_extra(
+                                &expected_label,
+                                expected,
+                                &found_label,
+                                found,
+                                sort_string(values.expected),
+                                sort_string(values.found),
+                            );
                         }
                     }
                 }
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index 0c9535dfaa628..b29f740ef0f2a 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -712,8 +712,8 @@ impl String {
         }
     }
 
-    /// Decode a UTF-16–encoded vector `v` into a `String`, returning [`Err`]
-    /// if `v` contains any invalid data.
+    /// Decode a native endian UTF-16–encoded vector `v` into a `String`,
+    /// returning [`Err`] if `v` contains any invalid data.
     ///
     /// # Examples
     ///
@@ -745,8 +745,8 @@ impl String {
         Ok(ret)
     }
 
-    /// Decode a UTF-16–encoded slice `v` into a `String`, replacing
-    /// invalid data with [the replacement character (`U+FFFD`)][U+FFFD].
+    /// Decode a native endian UTF-16–encoded slice `v` into a `String`,
+    /// replacing invalid data with [the replacement character (`U+FFFD`)][U+FFFD].
     ///
     /// Unlike [`from_utf8_lossy`] which returns a [`Cow<'a, str>`],
     /// `from_utf16_lossy` returns a `String` since the UTF-16 to UTF-8
@@ -777,8 +777,8 @@ impl String {
             .collect()
     }
 
-    /// Decode a UTF-16LE–encoded vector `v` into a `String`, returning [`Err`]
-    /// if `v` contains any invalid data.
+    /// Decode a UTF-16LE–encoded vector `v` into a `String`,
+    /// returning [`Err`] if `v` contains any invalid data.
     ///
     /// # Examples
     ///
@@ -852,8 +852,8 @@ impl String {
         }
     }
 
-    /// Decode a UTF-16BE–encoded vector `v` into a `String`, returning [`Err`]
-    /// if `v` contains any invalid data.
+    /// Decode a UTF-16BE–encoded vector `v` into a `String`,
+    /// returning [`Err`] if `v` contains any invalid data.
     ///
     /// # Examples
     ///
diff --git a/library/core/src/char/methods.rs b/library/core/src/char/methods.rs
index fb8a740aced13..ccfdbf0eb704d 100644
--- a/library/core/src/char/methods.rs
+++ b/library/core/src/char/methods.rs
@@ -92,7 +92,7 @@ impl char {
     #[stable(feature = "assoc_char_consts", since = "1.52.0")]
     pub const UNICODE_VERSION: (u8, u8, u8) = crate::unicode::UNICODE_VERSION;
 
-    /// Creates an iterator over the UTF-16 encoded code points in `iter`,
+    /// Creates an iterator over the native endian UTF-16 encoded code points in `iter`,
     /// returning unpaired surrogates as `Err`s.
     ///
     /// # Examples
@@ -704,7 +704,7 @@ impl char {
         unsafe { from_utf8_unchecked_mut(encode_utf8_raw(self as u32, dst)) }
     }
 
-    /// Encodes this character as UTF-16 into the provided `u16` buffer,
+    /// Encodes this character as native endian UTF-16 into the provided `u16` buffer,
     /// and then returns the subslice of the buffer that contains the encoded character.
     ///
     /// # Panics
@@ -1828,7 +1828,7 @@ pub const fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> &mut [u8] {
     unsafe { slice::from_raw_parts_mut(dst.as_mut_ptr(), len) }
 }
 
-/// Encodes a raw `u32` value as UTF-16 into the provided `u16` buffer,
+/// Encodes a raw `u32` value as native endian UTF-16 into the provided `u16` buffer,
 /// and then returns the subslice of the buffer that contains the encoded character.
 ///
 /// Unlike `char::encode_utf16`, this method also handles codepoints in the surrogate range.
diff --git a/library/core/src/intrinsics/mod.rs b/library/core/src/intrinsics/mod.rs
index c0d435f99c0ca..bf07632d9928b 100644
--- a/library/core/src/intrinsics/mod.rs
+++ b/library/core/src/intrinsics/mod.rs
@@ -78,7 +78,11 @@ pub mod simd;
 use crate::sync::atomic::{self, AtomicBool, AtomicI32, AtomicIsize, AtomicU32, Ordering};
 
 #[stable(feature = "drop_in_place", since = "1.8.0")]
-#[rustc_allowed_through_unstable_modules]
+#[cfg_attr(bootstrap, rustc_allowed_through_unstable_modules)]
+#[cfg_attr(
+    not(bootstrap),
+    rustc_allowed_through_unstable_modules = "import this function via `std::ptr` instead"
+)]
 #[deprecated(note = "no longer an intrinsic - use `ptr::drop_in_place` directly", since = "1.52.0")]
 #[inline]
 pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs
index 01a3c9d2ada72..3669051ce82d3 100644
--- a/library/core/src/macros/mod.rs
+++ b/library/core/src/macros/mod.rs
@@ -1831,32 +1831,4 @@ pub(crate) mod builtin {
     pub macro deref($pat:pat) {
         builtin # deref($pat)
     }
-
-    /// Derive macro for `rustc-serialize`. Should not be used in new code.
-    #[rustc_builtin_macro]
-    #[unstable(
-        feature = "rustc_encodable_decodable",
-        issue = "none",
-        soft,
-        reason = "derive macro for `rustc-serialize`; should not be used in new code"
-    )]
-    #[deprecated(since = "1.52.0", note = "rustc-serialize is deprecated and no longer supported")]
-    #[doc(hidden)] // While technically stable, using it is unstable, and deprecated. Hide it.
-    pub macro RustcDecodable($item:item) {
-        /* compiler built-in */
-    }
-
-    /// Derive macro for `rustc-serialize`. Should not be used in new code.
-    #[rustc_builtin_macro]
-    #[unstable(
-        feature = "rustc_encodable_decodable",
-        issue = "none",
-        soft,
-        reason = "derive macro for `rustc-serialize`; should not be used in new code"
-    )]
-    #[deprecated(since = "1.52.0", note = "rustc-serialize is deprecated and no longer supported")]
-    #[doc(hidden)] // While technically stable, using it is unstable, and deprecated. Hide it.
-    pub macro RustcEncodable($item:item) {
-        /* compiler built-in */
-    }
 }
diff --git a/library/core/src/prelude/mod.rs b/library/core/src/prelude/mod.rs
index d3fda1cd273f9..0ab97f5bbd50e 100644
--- a/library/core/src/prelude/mod.rs
+++ b/library/core/src/prelude/mod.rs
@@ -18,16 +18,6 @@ mod common;
 pub mod v1 {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub use super::common::*;
-
-    // Do not `doc(inline)` these `doc(hidden)` items.
-    #[unstable(
-        feature = "rustc_encodable_decodable",
-        issue = "none",
-        soft,
-        reason = "derive macro for `rustc-serialize`; should not be used in new code"
-    )]
-    #[allow(deprecated)]
-    pub use crate::macros::builtin::{RustcDecodable, RustcEncodable};
 }
 
 /// The 2015 version of the core prelude.
diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs
index 8a473b398bb5f..39fa6c1a25fe9 100644
--- a/library/core/src/str/mod.rs
+++ b/library/core/src/str/mod.rs
@@ -1108,7 +1108,8 @@ impl str {
         LinesAny(self.lines())
     }
 
-    /// Returns an iterator of `u16` over the string encoded as UTF-16.
+    /// Returns an iterator of `u16` over the string encoded
+    /// as native endian UTF-16 (without byte-order mark).
     ///
     /// # Examples
     ///
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
index 9eab75b06961f..944c34385572d 100644
--- a/library/std/Cargo.toml
+++ b/library/std/Cargo.toml
@@ -7,6 +7,7 @@ license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/rust.git"
 description = "The Rust Standard Library"
 edition = "2021"
+autobenches = false
 
 [lib]
 crate-type = ["dylib", "rlib"]
@@ -130,6 +131,18 @@ name = "pipe-subprocess"
 path = "tests/pipe_subprocess.rs"
 harness = false
 
+[[test]]
+name = "sync"
+path = "tests/sync/lib.rs"
+
+[[test]]
+name = "floats"
+path = "tests/floats/lib.rs"
+
+[[test]]
+name = "thread_local"
+path = "tests/thread_local/lib.rs"
+
 [[bench]]
 name = "stdbenches"
 path = "benches/lib.rs"
diff --git a/library/std/benches/lib.rs b/library/std/benches/lib.rs
index 1b21c230a0bf2..e749d9c0f7998 100644
--- a/library/std/benches/lib.rs
+++ b/library/std/benches/lib.rs
@@ -5,3 +5,5 @@
 extern crate test;
 
 mod hash;
+mod path;
+mod time;
diff --git a/library/std/benches/path.rs b/library/std/benches/path.rs
new file mode 100644
index 0000000000000..094c00894a8ee
--- /dev/null
+++ b/library/std/benches/path.rs
@@ -0,0 +1,114 @@
+use core::hint::black_box;
+use std::collections::{BTreeSet, HashSet};
+use std::hash::{DefaultHasher, Hash, Hasher};
+use std::path::*;
+
+#[bench]
+#[cfg_attr(miri, ignore)] // Miri isn't fast...
+fn bench_path_cmp_fast_path_buf_sort(b: &mut test::Bencher) {
+    let prefix = "my/home";
+    let mut paths: Vec<_> =
+        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
+
+    paths.sort();
+
+    b.iter(|| {
+        black_box(paths.as_mut_slice()).sort_unstable();
+    });
+}
+
+#[bench]
+#[cfg_attr(miri, ignore)] // Miri isn't fast...
+fn bench_path_cmp_fast_path_long(b: &mut test::Bencher) {
+    let prefix = "/my/home/is/my/castle/and/my/castle/has/a/rusty/workbench/";
+    let paths: Vec<_> =
+        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
+
+    let mut set = BTreeSet::new();
+
+    paths.iter().for_each(|p| {
+        set.insert(p.as_path());
+    });
+
+    b.iter(|| {
+        set.remove(paths[500].as_path());
+        set.insert(paths[500].as_path());
+    });
+}
+
+#[bench]
+#[cfg_attr(miri, ignore)] // Miri isn't fast...
+fn bench_path_cmp_fast_path_short(b: &mut test::Bencher) {
+    let prefix = "my/home";
+    let paths: Vec<_> =
+        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
+
+    let mut set = BTreeSet::new();
+
+    paths.iter().for_each(|p| {
+        set.insert(p.as_path());
+    });
+
+    b.iter(|| {
+        set.remove(paths[500].as_path());
+        set.insert(paths[500].as_path());
+    });
+}
+
+#[bench]
+#[cfg_attr(miri, ignore)] // Miri isn't fast...
+fn bench_path_hashset(b: &mut test::Bencher) {
+    let prefix = "/my/home/is/my/castle/and/my/castle/has/a/rusty/workbench/";
+    let paths: Vec<_> =
+        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
+
+    let mut set = HashSet::new();
+
+    paths.iter().for_each(|p| {
+        set.insert(p.as_path());
+    });
+
+    b.iter(|| {
+        set.remove(paths[500].as_path());
+        set.insert(black_box(paths[500].as_path()))
+    });
+}
+
+#[bench]
+#[cfg_attr(miri, ignore)] // Miri isn't fast...
+fn bench_path_hashset_miss(b: &mut test::Bencher) {
+    let prefix = "/my/home/is/my/castle/and/my/castle/has/a/rusty/workbench/";
+    let paths: Vec<_> =
+        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
+
+    let mut set = HashSet::new();
+
+    paths.iter().for_each(|p| {
+        set.insert(p.as_path());
+    });
+
+    let probe = PathBuf::from(prefix).join("other");
+
+    b.iter(|| set.remove(black_box(probe.as_path())));
+}
+
+#[bench]
+fn bench_hash_path_short(b: &mut test::Bencher) {
+    let mut hasher = DefaultHasher::new();
+    let path = Path::new("explorer.exe");
+
+    b.iter(|| black_box(path).hash(&mut hasher));
+
+    black_box(hasher.finish());
+}
+
+#[bench]
+fn bench_hash_path_long(b: &mut test::Bencher) {
+    let mut hasher = DefaultHasher::new();
+    let path =
+        Path::new("/aaaaa/aaaaaa/./../aaaaaaaa/bbbbbbbbbbbbb/ccccccccccc/ddddddddd/eeeeeee.fff");
+
+    b.iter(|| black_box(path).hash(&mut hasher));
+
+    black_box(hasher.finish());
+}
diff --git a/library/std/benches/time.rs b/library/std/benches/time.rs
new file mode 100644
index 0000000000000..552481cad928a
--- /dev/null
+++ b/library/std/benches/time.rs
@@ -0,0 +1,47 @@
+use std::time::Instant;
+
+#[cfg(not(target_arch = "wasm32"))]
+use test::{Bencher, black_box};
+
+macro_rules! bench_instant_threaded {
+    ($bench_name:ident, $thread_count:expr) => {
+        #[bench]
+        #[cfg(not(target_arch = "wasm32"))]
+        fn $bench_name(b: &mut Bencher) -> std::thread::Result<()> {
+            use std::sync::Arc;
+            use std::sync::atomic::{AtomicBool, Ordering};
+
+            let running = Arc::new(AtomicBool::new(true));
+
+            let threads: Vec<_> = (0..$thread_count)
+                .map(|_| {
+                    let flag = Arc::clone(&running);
+                    std::thread::spawn(move || {
+                        while flag.load(Ordering::Relaxed) {
+                            black_box(Instant::now());
+                        }
+                    })
+                })
+                .collect();
+
+            b.iter(|| {
+                let a = Instant::now();
+                let b = Instant::now();
+                assert!(b >= a);
+            });
+
+            running.store(false, Ordering::Relaxed);
+
+            for t in threads {
+                t.join()?;
+            }
+            Ok(())
+        }
+    };
+}
+
+bench_instant_threaded!(instant_contention_01_threads, 0);
+bench_instant_threaded!(instant_contention_02_threads, 1);
+bench_instant_threaded!(instant_contention_04_threads, 3);
+bench_instant_threaded!(instant_contention_08_threads, 7);
+bench_instant_threaded!(instant_contention_16_threads, 15);
diff --git a/library/std/src/env.rs b/library/std/src/env.rs
index bbd506127fb67..c665dfd36247f 100644
--- a/library/std/src/env.rs
+++ b/library/std/src/env.rs
@@ -10,9 +10,6 @@
 
 #![stable(feature = "env", since = "1.0.0")]
 
-#[cfg(test)]
-mod tests;
-
 use crate::error::Error;
 use crate::ffi::{OsStr, OsString};
 use crate::path::{Path, PathBuf};
diff --git a/library/std/src/env/tests.rs b/library/std/src/env/tests.rs
deleted file mode 100644
index d021726106872..0000000000000
--- a/library/std/src/env/tests.rs
+++ /dev/null
@@ -1,120 +0,0 @@
-use super::*;
-
-#[test]
-#[cfg_attr(any(target_os = "emscripten", target_os = "wasi", target_env = "sgx"), ignore)]
-fn test_self_exe_path() {
-    let path = current_exe();
-    assert!(path.is_ok());
-    let path = path.unwrap();
-
-    // Hard to test this function
-    assert!(path.is_absolute());
-}
-
-#[test]
-fn test() {
-    assert!((!Path::new("test-path").is_absolute()));
-
-    #[cfg(not(target_env = "sgx"))]
-    current_dir().unwrap();
-}
-
-#[test]
-#[cfg(windows)]
-fn split_paths_windows() {
-    use crate::path::PathBuf;
-
-    fn check_parse(unparsed: &str, parsed: &[&str]) -> bool {
-        split_paths(unparsed).collect::<Vec<_>>()
-            == parsed.iter().map(|s| PathBuf::from(*s)).collect::<Vec<_>>()
-    }
-
-    assert!(check_parse("", &mut [""]));
-    assert!(check_parse(r#""""#, &mut [""]));
-    assert!(check_parse(";;", &mut ["", "", ""]));
-    assert!(check_parse(r"c:\", &mut [r"c:\"]));
-    assert!(check_parse(r"c:\;", &mut [r"c:\", ""]));
-    assert!(check_parse(r"c:\;c:\Program Files\", &mut [r"c:\", r"c:\Program Files\"]));
-    assert!(check_parse(r#"c:\;c:\"foo"\"#, &mut [r"c:\", r"c:\foo\"]));
-    assert!(check_parse(r#"c:\;c:\"foo;bar"\;c:\baz"#, &mut [r"c:\", r"c:\foo;bar\", r"c:\baz"]));
-}
-
-#[test]
-#[cfg(unix)]
-fn split_paths_unix() {
-    use crate::path::PathBuf;
-
-    fn check_parse(unparsed: &str, parsed: &[&str]) -> bool {
-        split_paths(unparsed).collect::<Vec<_>>()
-            == parsed.iter().map(|s| PathBuf::from(*s)).collect::<Vec<_>>()
-    }
-
-    assert!(check_parse("", &mut [""]));
-    assert!(check_parse("::", &mut ["", "", ""]));
-    assert!(check_parse("/", &mut ["/"]));
-    assert!(check_parse("/:", &mut ["/", ""]));
-    assert!(check_parse("/:/usr/local", &mut ["/", "/usr/local"]));
-}
-
-#[test]
-#[cfg(unix)]
-fn join_paths_unix() {
-    use crate::ffi::OsStr;
-
-    fn test_eq(input: &[&str], output: &str) -> bool {
-        &*join_paths(input.iter().cloned()).unwrap() == OsStr::new(output)
-    }
-
-    assert!(test_eq(&[], ""));
-    assert!(test_eq(&["/bin", "/usr/bin", "/usr/local/bin"], "/bin:/usr/bin:/usr/local/bin"));
-    assert!(test_eq(&["", "/bin", "", "", "/usr/bin", ""], ":/bin:::/usr/bin:"));
-    assert!(join_paths(["/te:st"].iter().cloned()).is_err());
-}
-
-#[test]
-#[cfg(windows)]
-fn join_paths_windows() {
-    use crate::ffi::OsStr;
-
-    fn test_eq(input: &[&str], output: &str) -> bool {
-        &*join_paths(input.iter().cloned()).unwrap() == OsStr::new(output)
-    }
-
-    assert!(test_eq(&[], ""));
-    assert!(test_eq(&[r"c:\windows", r"c:\"], r"c:\windows;c:\"));
-    assert!(test_eq(&["", r"c:\windows", "", "", r"c:\", ""], r";c:\windows;;;c:\;"));
-    assert!(test_eq(&[r"c:\te;st", r"c:\"], r#""c:\te;st";c:\"#));
-    assert!(join_paths([r#"c:\te"st"#].iter().cloned()).is_err());
-}
-
-#[test]
-fn args_debug() {
-    assert_eq!(
-        format!("Args {{ inner: {:?} }}", args().collect::<Vec<_>>()),
-        format!("{:?}", args())
-    );
-}
-
-#[test]
-fn args_os_debug() {
-    assert_eq!(
-        format!("ArgsOs {{ inner: {:?} }}", args_os().collect::<Vec<_>>()),
-        format!("{:?}", args_os())
-    );
-}
-
-#[test]
-fn vars_debug() {
-    assert_eq!(
-        format!("Vars {{ inner: {:?} }}", vars().collect::<Vec<_>>()),
-        format!("{:?}", vars())
-    );
-}
-
-#[test]
-fn vars_os_debug() {
-    assert_eq!(
-        format!("VarsOs {{ inner: {:?} }}", vars_os().collect::<Vec<_>>()),
-        format!("{:?}", vars_os())
-    );
-}
diff --git a/library/std/src/error.rs b/library/std/src/error.rs
index b3e63aaf1c567..def5f984c88e4 100644
--- a/library/std/src/error.rs
+++ b/library/std/src/error.rs
@@ -1,9 +1,6 @@
 #![doc = include_str!("../../core/src/error.md")]
 #![stable(feature = "rust1", since = "1.0.0")]
 
-#[cfg(test)]
-mod tests;
-
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::error::Error;
 #[unstable(feature = "error_generic_member_access", issue = "99301")]
diff --git a/library/std/src/f128.rs b/library/std/src/f128.rs
index d65f5ed61cfbc..89612fa747551 100644
--- a/library/std/src/f128.rs
+++ b/library/std/src/f128.rs
@@ -4,9 +4,6 @@
 //!
 //! Mathematically significant numbers are provided in the `consts` sub-module.
 
-#[cfg(test)]
-mod tests;
-
 #[unstable(feature = "f128", issue = "116909")]
 pub use core::f128::consts;
 
diff --git a/library/std/src/f16.rs b/library/std/src/f16.rs
index 5b0903bceabb4..cc523c93b4de7 100644
--- a/library/std/src/f16.rs
+++ b/library/std/src/f16.rs
@@ -4,9 +4,6 @@
 //!
 //! Mathematically significant numbers are provided in the `consts` sub-module.
 
-#[cfg(test)]
-mod tests;
-
 #[unstable(feature = "f16", issue = "116909")]
 pub use core::f16::consts;
 
diff --git a/library/std/src/f32.rs b/library/std/src/f32.rs
index f9b6723788ae3..260c499b7f4b9 100644
--- a/library/std/src/f32.rs
+++ b/library/std/src/f32.rs
@@ -12,9 +12,6 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 #![allow(missing_docs)]
 
-#[cfg(test)]
-mod tests;
-
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow(deprecated, deprecated_in_future)]
 pub use core::f32::{
diff --git a/library/std/src/f64.rs b/library/std/src/f64.rs
index 0de55a15d48e8..7af646f8cfd60 100644
--- a/library/std/src/f64.rs
+++ b/library/std/src/f64.rs
@@ -12,9 +12,6 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 #![allow(missing_docs)]
 
-#[cfg(test)]
-mod tests;
-
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow(deprecated, deprecated_in_future)]
 pub use core::f64::{
diff --git a/library/std/src/macros.rs b/library/std/src/macros.rs
index 1b0d7f3dbf2c9..e0f9f0bb5cee4 100644
--- a/library/std/src/macros.rs
+++ b/library/std/src/macros.rs
@@ -372,18 +372,3 @@ macro_rules! dbg {
         ($($crate::dbg!($val)),+,)
     };
 }
-
-/// Verify that floats are within a tolerance of each other, 1.0e-6 by default.
-#[cfg(test)]
-macro_rules! assert_approx_eq {
-    ($a:expr, $b:expr) => {{ assert_approx_eq!($a, $b, 1.0e-6) }};
-    ($a:expr, $b:expr, $lim:expr) => {{
-        let (a, b) = (&$a, &$b);
-        let diff = (*a - *b).abs();
-        assert!(
-            diff < $lim,
-            "{a:?} is not approximately equal to {b:?} (threshold {lim:?}, difference {diff:?})",
-            lim = $lim
-        );
-    }};
-}
diff --git a/library/std/src/num.rs b/library/std/src/num.rs
index d2f679e7dde54..ffb8789c906ef 100644
--- a/library/std/src/num.rs
+++ b/library/std/src/num.rs
@@ -6,9 +6,6 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 #![allow(missing_docs)]
 
-#[cfg(test)]
-mod tests;
-
 #[stable(feature = "int_error_matching", since = "1.55.0")]
 pub use core::num::IntErrorKind;
 #[stable(feature = "generic_nonzero", since = "1.79.0")]
@@ -29,28 +26,3 @@ pub use core::num::{FpCategory, ParseFloatError, ParseIntError, TryFromIntError}
 pub use core::num::{NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI128, NonZeroIsize};
 #[stable(feature = "nonzero", since = "1.28.0")]
 pub use core::num::{NonZeroU8, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU128, NonZeroUsize};
-
-#[cfg(test)]
-use crate::fmt;
-#[cfg(test)]
-use crate::ops::{Add, Div, Mul, Rem, Sub};
-
-/// Helper function for testing numeric operations
-#[cfg(test)]
-pub fn test_num<T>(ten: T, two: T)
-where
-    T: PartialEq
-        + Add<Output = T>
-        + Sub<Output = T>
-        + Mul<Output = T>
-        + Div<Output = T>
-        + Rem<Output = T>
-        + fmt::Debug
-        + Copy,
-{
-    assert_eq!(ten.add(two), ten + two);
-    assert_eq!(ten.sub(two), ten - two);
-    assert_eq!(ten.mul(two), ten * two);
-    assert_eq!(ten.div(two), ten / two);
-    assert_eq!(ten.rem(two), ten % two);
-}
diff --git a/library/std/src/panic.rs b/library/std/src/panic.rs
index d649357a56d71..153189b8b0315 100644
--- a/library/std/src/panic.rs
+++ b/library/std/src/panic.rs
@@ -529,6 +529,3 @@ pub fn get_backtrace_style() -> Option<BacktraceStyle> {
         Err(new) => BacktraceStyle::from_u8(new),
     }
 }
-
-#[cfg(test)]
-mod tests;
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 7fd08a97f1f20..97e17acadeac7 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -67,9 +67,6 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 #![deny(unsafe_op_in_unsafe_fn)]
 
-#[cfg(test)]
-mod tests;
-
 use core::clone::CloneToUninit;
 
 use crate::borrow::{Borrow, Cow};
diff --git a/library/std/src/prelude/mod.rs b/library/std/src/prelude/mod.rs
index 4ec328208f015..14e6c2715df0b 100644
--- a/library/std/src/prelude/mod.rs
+++ b/library/std/src/prelude/mod.rs
@@ -120,16 +120,6 @@ mod common;
 pub mod v1 {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub use super::common::*;
-
-    // Do not `doc(inline)` these `doc(hidden)` items.
-    #[unstable(
-        feature = "rustc_encodable_decodable",
-        issue = "none",
-        soft,
-        reason = "derive macro for `rustc-serialize`; should not be used in new code"
-    )]
-    #[allow(deprecated)]
-    pub use core::prelude::v1::{RustcDecodable, RustcEncodable};
 }
 
 /// The 2015 version of the prelude of The Rust Standard Library.
diff --git a/library/std/src/sync/barrier.rs b/library/std/src/sync/barrier.rs
index 862753e4765dc..067ff66d9af73 100644
--- a/library/std/src/sync/barrier.rs
+++ b/library/std/src/sync/barrier.rs
@@ -1,6 +1,3 @@
-#[cfg(test)]
-mod tests;
-
 use crate::fmt;
 // FIXME(nonpoison_mutex,nonpoison_condvar): switch to nonpoison versions once they are available
 use crate::sync::{Condvar, Mutex};
diff --git a/library/std/src/sync/lazy_lock.rs b/library/std/src/sync/lazy_lock.rs
index 98c83d8d326ca..78cf8841efefb 100644
--- a/library/std/src/sync/lazy_lock.rs
+++ b/library/std/src/sync/lazy_lock.rs
@@ -350,6 +350,3 @@ unsafe impl<T: Sync + Send, F: Send> Sync for LazyLock<T, F> {}
 impl<T: RefUnwindSafe + UnwindSafe, F: UnwindSafe> RefUnwindSafe for LazyLock<T, F> {}
 #[stable(feature = "lazy_cell", since = "1.80.0")]
 impl<T: UnwindSafe, F: UnwindSafe> UnwindSafe for LazyLock<T, F> {}
-
-#[cfg(test)]
-mod tests;
diff --git a/library/std/src/sync/mpsc/mod.rs b/library/std/src/sync/mpsc.rs
similarity index 99%
rename from library/std/src/sync/mpsc/mod.rs
rename to library/std/src/sync/mpsc.rs
index c86b546e01169..f942937c14d11 100644
--- a/library/std/src/sync/mpsc/mod.rs
+++ b/library/std/src/sync/mpsc.rs
@@ -137,12 +137,6 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
-mod tests;
-
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
-mod sync_tests;
-
 // MPSC channels are built as a wrapper around MPMC channels, which
 // were ported from the `crossbeam-channel` crate. MPMC channels are
 // not exposed publicly, but if you are curious about the implementation,
@@ -737,9 +731,10 @@ impl<T> SyncSender<T> {
     // Attempts to send for a value on this receiver, returning an error if the
     // corresponding channel has hung up, or if it waits more than `timeout`.
     //
-    // This method is currently private and only used for tests.
-    #[allow(unused)]
-    fn send_timeout(&self, t: T, timeout: Duration) -> Result<(), mpmc::SendTimeoutError<T>> {
+    // This method is currently only used for tests.
+    #[unstable(issue = "none", feature = "std_internals")]
+    #[doc(hidden)]
+    pub fn send_timeout(&self, t: T, timeout: Duration) -> Result<(), mpmc::SendTimeoutError<T>> {
         self.inner.send_timeout(t, timeout)
     }
 }
diff --git a/library/std/src/sync/once_lock.rs b/library/std/src/sync/once_lock.rs
index 6fc0abbed9e15..fdba802ecace7 100644
--- a/library/std/src/sync/once_lock.rs
+++ b/library/std/src/sync/once_lock.rs
@@ -674,6 +674,3 @@ unsafe impl<#[may_dangle] T> Drop for OnceLock<T> {
         }
     }
 }
-
-#[cfg(test)]
-mod tests;
diff --git a/library/std/src/sync/poison/condvar.rs b/library/std/src/sync/poison/condvar.rs
index a6e2389c93baf..7f0f3f652bcb7 100644
--- a/library/std/src/sync/poison/condvar.rs
+++ b/library/std/src/sync/poison/condvar.rs
@@ -1,6 +1,3 @@
-#[cfg(test)]
-mod tests;
-
 use crate::fmt;
 use crate::sync::poison::{self, LockResult, MutexGuard, PoisonError, mutex};
 use crate::sys::sync as sys;
diff --git a/library/std/src/sync/poison/mutex.rs b/library/std/src/sync/poison/mutex.rs
index fb43ada637543..9362c764173a8 100644
--- a/library/std/src/sync/poison/mutex.rs
+++ b/library/std/src/sync/poison/mutex.rs
@@ -1,6 +1,3 @@
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
-mod tests;
-
 use crate::cell::UnsafeCell;
 use crate::fmt;
 use crate::marker::PhantomData;
diff --git a/library/std/src/sync/poison/once.rs b/library/std/src/sync/poison/once.rs
index 528b11ca0c1e6..d2938b7a0c12e 100644
--- a/library/std/src/sync/poison/once.rs
+++ b/library/std/src/sync/poison/once.rs
@@ -3,9 +3,6 @@
 //! This primitive is meant to be used to run one-time initialization. An
 //! example use case would be for initializing an FFI library.
 
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
-mod tests;
-
 use crate::fmt;
 use crate::panic::{RefUnwindSafe, UnwindSafe};
 use crate::sys::sync as sys;
diff --git a/library/std/src/sync/poison/rwlock.rs b/library/std/src/sync/poison/rwlock.rs
index 1519baf99a8fd..f9d9321f5f2d8 100644
--- a/library/std/src/sync/poison/rwlock.rs
+++ b/library/std/src/sync/poison/rwlock.rs
@@ -1,6 +1,3 @@
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
-mod tests;
-
 use crate::cell::UnsafeCell;
 use crate::fmt;
 use crate::marker::PhantomData;
diff --git a/library/std/src/sync/reentrant_lock.rs b/library/std/src/sync/reentrant_lock.rs
index 0140e0d21299f..e009eb410efc0 100644
--- a/library/std/src/sync/reentrant_lock.rs
+++ b/library/std/src/sync/reentrant_lock.rs
@@ -1,6 +1,3 @@
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
-mod tests;
-
 use cfg_if::cfg_if;
 
 use crate::cell::UnsafeCell;
@@ -324,7 +321,10 @@ impl<T: ?Sized> ReentrantLock<T> {
     /// Otherwise, an RAII guard is returned.
     ///
     /// This function does not block.
-    pub(crate) fn try_lock(&self) -> Option<ReentrantLockGuard<'_, T>> {
+    // FIXME maybe make it a public part of the API?
+    #[unstable(issue = "none", feature = "std_internals")]
+    #[doc(hidden)]
+    pub fn try_lock(&self) -> Option<ReentrantLockGuard<'_, T>> {
         let this_thread = current_id();
         // Safety: We only touch lock_count when we own the inner mutex.
         // Additionally, we only call `self.owner.set()` while holding
diff --git a/library/std/src/thread/local.rs b/library/std/src/thread/local.rs
index c003503ca8b09..ca04aa4ada497 100644
--- a/library/std/src/thread/local.rs
+++ b/library/std/src/thread/local.rs
@@ -2,12 +2,6 @@
 
 #![unstable(feature = "thread_local_internals", issue = "none")]
 
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
-mod tests;
-
-#[cfg(test)]
-mod dynamic_tests;
-
 use crate::cell::{Cell, RefCell};
 use crate::error::Error;
 use crate::fmt;
diff --git a/library/std/src/time.rs b/library/std/src/time.rs
index 9f4f8a0d0880c..88b3e9e0ceba0 100644
--- a/library/std/src/time.rs
+++ b/library/std/src/time.rs
@@ -31,9 +31,6 @@
 
 #![stable(feature = "time", since = "1.3.0")]
 
-#[cfg(test)]
-mod tests;
-
 #[stable(feature = "time", since = "1.3.0")]
 pub use core::time::Duration;
 #[stable(feature = "duration_checked_float", since = "1.66.0")]
diff --git a/library/std/tests/env.rs b/library/std/tests/env.rs
index 44fe84c989fb7..e754cf8263b0f 100644
--- a/library/std/tests/env.rs
+++ b/library/std/tests/env.rs
@@ -1,163 +1,123 @@
 use std::env::*;
-use std::ffi::{OsStr, OsString};
-
-use rand::distributions::{Alphanumeric, DistString};
+use std::path::Path;
 
 mod common;
-use std::thread;
-
-use common::test_rng;
-
-#[track_caller]
-fn make_rand_name() -> OsString {
-    let n = format!("TEST{}", Alphanumeric.sample_string(&mut test_rng(), 10));
-    let n = OsString::from(n);
-    assert!(var_os(&n).is_none());
-    n
-}
-
-fn eq(a: Option<OsString>, b: Option<&str>) {
-    assert_eq!(a.as_ref().map(|s| &**s), b.map(OsStr::new).map(|s| &*s));
-}
 
 #[test]
-fn test_set_var() {
-    let n = make_rand_name();
-    set_var(&n, "VALUE");
-    eq(var_os(&n), Some("VALUE"));
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi", target_env = "sgx"), ignore)]
+fn test_self_exe_path() {
+    let path = current_exe();
+    assert!(path.is_ok());
+    let path = path.unwrap();
+
+    // Hard to test this function
+    assert!(path.is_absolute());
 }
 
 #[test]
-fn test_remove_var() {
-    let n = make_rand_name();
-    set_var(&n, "VALUE");
-    remove_var(&n);
-    eq(var_os(&n), None);
-}
+fn test() {
+    assert!((!Path::new("test-path").is_absolute()));
 
-#[test]
-fn test_set_var_overwrite() {
-    let n = make_rand_name();
-    set_var(&n, "1");
-    set_var(&n, "2");
-    eq(var_os(&n), Some("2"));
-    set_var(&n, "");
-    eq(var_os(&n), Some(""));
+    #[cfg(not(target_env = "sgx"))]
+    current_dir().unwrap();
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
-fn test_var_big() {
-    let mut s = "".to_string();
-    let mut i = 0;
-    while i < 100 {
-        s.push_str("aaaaaaaaaa");
-        i += 1;
+#[cfg(windows)]
+fn split_paths_windows() {
+    use std::path::PathBuf;
+
+    fn check_parse(unparsed: &str, parsed: &[&str]) -> bool {
+        split_paths(unparsed).collect::<Vec<_>>()
+            == parsed.iter().map(|s| PathBuf::from(*s)).collect::<Vec<_>>()
     }
-    let n = make_rand_name();
-    set_var(&n, &s);
-    eq(var_os(&n), Some(&s));
-}
 
-#[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
-fn test_env_set_get_huge() {
-    let n = make_rand_name();
-    let s = "x".repeat(10000);
-    set_var(&n, &s);
-    eq(var_os(&n), Some(&s));
-    remove_var(&n);
-    eq(var_os(&n), None);
+    assert!(check_parse("", &mut [""]));
+    assert!(check_parse(r#""""#, &mut [""]));
+    assert!(check_parse(";;", &mut ["", "", ""]));
+    assert!(check_parse(r"c:\", &mut [r"c:\"]));
+    assert!(check_parse(r"c:\;", &mut [r"c:\", ""]));
+    assert!(check_parse(r"c:\;c:\Program Files\", &mut [r"c:\", r"c:\Program Files\"]));
+    assert!(check_parse(r#"c:\;c:\"foo"\"#, &mut [r"c:\", r"c:\foo\"]));
+    assert!(check_parse(r#"c:\;c:\"foo;bar"\;c:\baz"#, &mut [r"c:\", r"c:\foo;bar\", r"c:\baz"]));
 }
 
 #[test]
-fn test_env_set_var() {
-    let n = make_rand_name();
+#[cfg(unix)]
+fn split_paths_unix() {
+    use std::path::PathBuf;
 
-    let mut e = vars_os();
-    set_var(&n, "VALUE");
-    assert!(!e.any(|(k, v)| { &*k == &*n && &*v == "VALUE" }));
+    fn check_parse(unparsed: &str, parsed: &[&str]) -> bool {
+        split_paths(unparsed).collect::<Vec<_>>()
+            == parsed.iter().map(|s| PathBuf::from(*s)).collect::<Vec<_>>()
+    }
 
-    assert!(vars_os().any(|(k, v)| { &*k == &*n && &*v == "VALUE" }));
+    assert!(check_parse("", &mut [""]));
+    assert!(check_parse("::", &mut ["", "", ""]));
+    assert!(check_parse("/", &mut ["/"]));
+    assert!(check_parse("/:", &mut ["/", ""]));
+    assert!(check_parse("/:/usr/local", &mut ["/", "/usr/local"]));
 }
 
 #[test]
-#[cfg_attr(not(any(unix, windows)), ignore, allow(unused))]
-#[allow(deprecated)]
-fn env_home_dir() {
-    use std::path::PathBuf;
+#[cfg(unix)]
+fn join_paths_unix() {
+    use std::ffi::OsStr;
 
-    fn var_to_os_string(var: Result<String, VarError>) -> Option<OsString> {
-        match var {
-            Ok(var) => Some(OsString::from(var)),
-            Err(VarError::NotUnicode(var)) => Some(var),
-            _ => None,
-        }
+    fn test_eq(input: &[&str], output: &str) -> bool {
+        &*join_paths(input.iter().cloned()).unwrap() == OsStr::new(output)
     }
 
-    cfg_if::cfg_if! {
-        if #[cfg(unix)] {
-            let oldhome = var_to_os_string(var("HOME"));
-
-            set_var("HOME", "/home/MountainView");
-            assert_eq!(home_dir(), Some(PathBuf::from("/home/MountainView")));
-
-            remove_var("HOME");
-            if cfg!(target_os = "android") {
-                assert!(home_dir().is_none());
-            } else {
-                // When HOME is not set, some platforms return `None`,
-                // but others return `Some` with a default.
-                // Just check that it is not "/home/MountainView".
-                assert_ne!(home_dir(), Some(PathBuf::from("/home/MountainView")));
-            }
-
-            if let Some(oldhome) = oldhome { set_var("HOME", oldhome); }
-        } else if #[cfg(windows)] {
-            let oldhome = var_to_os_string(var("HOME"));
-            let olduserprofile = var_to_os_string(var("USERPROFILE"));
-
-            remove_var("HOME");
-            remove_var("USERPROFILE");
-
-            assert!(home_dir().is_some());
-
-            set_var("HOME", "/home/PaloAlto");
-            assert_ne!(home_dir(), Some(PathBuf::from("/home/PaloAlto")), "HOME must not be used");
+    assert!(test_eq(&[], ""));
+    assert!(test_eq(&["/bin", "/usr/bin", "/usr/local/bin"], "/bin:/usr/bin:/usr/local/bin"));
+    assert!(test_eq(&["", "/bin", "", "", "/usr/bin", ""], ":/bin:::/usr/bin:"));
+    assert!(join_paths(["/te:st"].iter().cloned()).is_err());
+}
 
-            set_var("USERPROFILE", "/home/MountainView");
-            assert_eq!(home_dir(), Some(PathBuf::from("/home/MountainView")));
+#[test]
+#[cfg(windows)]
+fn join_paths_windows() {
+    use std::ffi::OsStr;
 
-            remove_var("HOME");
+    fn test_eq(input: &[&str], output: &str) -> bool {
+        &*join_paths(input.iter().cloned()).unwrap() == OsStr::new(output)
+    }
 
-            assert_eq!(home_dir(), Some(PathBuf::from("/home/MountainView")));
+    assert!(test_eq(&[], ""));
+    assert!(test_eq(&[r"c:\windows", r"c:\"], r"c:\windows;c:\"));
+    assert!(test_eq(&["", r"c:\windows", "", "", r"c:\", ""], r";c:\windows;;;c:\;"));
+    assert!(test_eq(&[r"c:\te;st", r"c:\"], r#""c:\te;st";c:\"#));
+    assert!(join_paths([r#"c:\te"st"#].iter().cloned()).is_err());
+}
 
-            set_var("USERPROFILE", "");
-            assert_ne!(home_dir(), Some(PathBuf::from("")), "Empty USERPROFILE must be ignored");
+#[test]
+fn args_debug() {
+    assert_eq!(
+        format!("Args {{ inner: {:?} }}", args().collect::<Vec<_>>()),
+        format!("{:?}", args())
+    );
+}
 
-            remove_var("USERPROFILE");
+#[test]
+fn args_os_debug() {
+    assert_eq!(
+        format!("ArgsOs {{ inner: {:?} }}", args_os().collect::<Vec<_>>()),
+        format!("{:?}", args_os())
+    );
+}
 
-            if let Some(oldhome) = oldhome { set_var("HOME", oldhome); }
-            if let Some(olduserprofile) = olduserprofile { set_var("USERPROFILE", olduserprofile); }
-        }
-    }
+#[test]
+fn vars_debug() {
+    assert_eq!(
+        format!("Vars {{ inner: {:?} }}", vars().collect::<Vec<_>>()),
+        format!("{:?}", vars())
+    );
 }
 
-#[test] // miri shouldn't detect any data race in this fn
-#[cfg_attr(any(not(miri), target_os = "emscripten"), ignore)]
-fn test_env_get_set_multithreaded() {
-    let getter = thread::spawn(|| {
-        for _ in 0..100 {
-            let _ = var_os("foo");
-        }
-    });
-
-    let setter = thread::spawn(|| {
-        for _ in 0..100 {
-            set_var("foo", "bar");
-        }
-    });
-
-    let _ = getter.join();
-    let _ = setter.join();
+#[test]
+fn vars_os_debug() {
+    assert_eq!(
+        format!("VarsOs {{ inner: {:?} }}", vars_os().collect::<Vec<_>>()),
+        format!("{:?}", vars_os())
+    );
 }
diff --git a/library/std/tests/env_modify.rs b/library/std/tests/env_modify.rs
new file mode 100644
index 0000000000000..6074744735005
--- /dev/null
+++ b/library/std/tests/env_modify.rs
@@ -0,0 +1,166 @@
+// These tests are in a separate integration test as they modify the environment,
+// and would otherwise cause some other tests to fail.
+
+use std::env::*;
+use std::ffi::{OsStr, OsString};
+
+use rand::distributions::{Alphanumeric, DistString};
+
+mod common;
+use std::thread;
+
+use common::test_rng;
+
+#[track_caller]
+fn make_rand_name() -> OsString {
+    let n = format!("TEST{}", Alphanumeric.sample_string(&mut test_rng(), 10));
+    let n = OsString::from(n);
+    assert!(var_os(&n).is_none());
+    n
+}
+
+fn eq(a: Option<OsString>, b: Option<&str>) {
+    assert_eq!(a.as_ref().map(|s| &**s), b.map(OsStr::new).map(|s| &*s));
+}
+
+#[test]
+fn test_set_var() {
+    let n = make_rand_name();
+    set_var(&n, "VALUE");
+    eq(var_os(&n), Some("VALUE"));
+}
+
+#[test]
+fn test_remove_var() {
+    let n = make_rand_name();
+    set_var(&n, "VALUE");
+    remove_var(&n);
+    eq(var_os(&n), None);
+}
+
+#[test]
+fn test_set_var_overwrite() {
+    let n = make_rand_name();
+    set_var(&n, "1");
+    set_var(&n, "2");
+    eq(var_os(&n), Some("2"));
+    set_var(&n, "");
+    eq(var_os(&n), Some(""));
+}
+
+#[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
+fn test_var_big() {
+    let mut s = "".to_string();
+    let mut i = 0;
+    while i < 100 {
+        s.push_str("aaaaaaaaaa");
+        i += 1;
+    }
+    let n = make_rand_name();
+    set_var(&n, &s);
+    eq(var_os(&n), Some(&s));
+}
+
+#[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
+fn test_env_set_get_huge() {
+    let n = make_rand_name();
+    let s = "x".repeat(10000);
+    set_var(&n, &s);
+    eq(var_os(&n), Some(&s));
+    remove_var(&n);
+    eq(var_os(&n), None);
+}
+
+#[test]
+fn test_env_set_var() {
+    let n = make_rand_name();
+
+    let mut e = vars_os();
+    set_var(&n, "VALUE");
+    assert!(!e.any(|(k, v)| { &*k == &*n && &*v == "VALUE" }));
+
+    assert!(vars_os().any(|(k, v)| { &*k == &*n && &*v == "VALUE" }));
+}
+
+#[test]
+#[cfg_attr(not(any(unix, windows)), ignore, allow(unused))]
+#[allow(deprecated)]
+fn env_home_dir() {
+    use std::path::PathBuf;
+
+    fn var_to_os_string(var: Result<String, VarError>) -> Option<OsString> {
+        match var {
+            Ok(var) => Some(OsString::from(var)),
+            Err(VarError::NotUnicode(var)) => Some(var),
+            _ => None,
+        }
+    }
+
+    cfg_if::cfg_if! {
+        if #[cfg(unix)] {
+            let oldhome = var_to_os_string(var("HOME"));
+
+            set_var("HOME", "/home/MountainView");
+            assert_eq!(home_dir(), Some(PathBuf::from("/home/MountainView")));
+
+            remove_var("HOME");
+            if cfg!(target_os = "android") {
+                assert!(home_dir().is_none());
+            } else {
+                // When HOME is not set, some platforms return `None`,
+                // but others return `Some` with a default.
+                // Just check that it is not "/home/MountainView".
+                assert_ne!(home_dir(), Some(PathBuf::from("/home/MountainView")));
+            }
+
+            if let Some(oldhome) = oldhome { set_var("HOME", oldhome); }
+        } else if #[cfg(windows)] {
+            let oldhome = var_to_os_string(var("HOME"));
+            let olduserprofile = var_to_os_string(var("USERPROFILE"));
+
+            remove_var("HOME");
+            remove_var("USERPROFILE");
+
+            assert!(home_dir().is_some());
+
+            set_var("HOME", "/home/PaloAlto");
+            assert_ne!(home_dir(), Some(PathBuf::from("/home/PaloAlto")), "HOME must not be used");
+
+            set_var("USERPROFILE", "/home/MountainView");
+            assert_eq!(home_dir(), Some(PathBuf::from("/home/MountainView")));
+
+            remove_var("HOME");
+
+            assert_eq!(home_dir(), Some(PathBuf::from("/home/MountainView")));
+
+            set_var("USERPROFILE", "");
+            assert_ne!(home_dir(), Some(PathBuf::from("")), "Empty USERPROFILE must be ignored");
+
+            remove_var("USERPROFILE");
+
+            if let Some(oldhome) = oldhome { set_var("HOME", oldhome); }
+            if let Some(olduserprofile) = olduserprofile { set_var("USERPROFILE", olduserprofile); }
+        }
+    }
+}
+
+#[test] // miri shouldn't detect any data race in this fn
+#[cfg_attr(any(not(miri), target_os = "emscripten"), ignore)]
+fn test_env_get_set_multithreaded() {
+    let getter = thread::spawn(|| {
+        for _ in 0..100 {
+            let _ = var_os("foo");
+        }
+    });
+
+    let setter = thread::spawn(|| {
+        for _ in 0..100 {
+            set_var("foo", "bar");
+        }
+    });
+
+    let _ = getter.join();
+    let _ = setter.join();
+}
diff --git a/library/std/src/error/tests.rs b/library/std/tests/error.rs
similarity index 98%
rename from library/std/src/error/tests.rs
rename to library/std/tests/error.rs
index 88a9f33c07908..8fd6eb3c02065 100644
--- a/library/std/src/error/tests.rs
+++ b/library/std/tests/error.rs
@@ -1,7 +1,8 @@
-use core::error::Request;
+#![feature(error_generic_member_access, error_reporter)]
 
-use super::Error;
-use crate::fmt;
+use std::backtrace::Backtrace;
+use std::error::{Error, Report, Request};
+use std::fmt;
 
 #[derive(Debug, PartialEq)]
 struct A;
@@ -38,9 +39,6 @@ fn downcasting() {
     }
 }
 
-use crate::backtrace::Backtrace;
-use crate::error::Report;
-
 #[derive(Debug)]
 struct SuperError {
     source: SuperErrorSideKick,
diff --git a/library/std/src/f128/tests.rs b/library/std/tests/floats/f128.rs
similarity index 99%
rename from library/std/src/f128/tests.rs
rename to library/std/tests/floats/f128.rs
index cbcf9f96239bb..d0e8b157e6b6f 100644
--- a/library/std/src/f128/tests.rs
+++ b/library/std/tests/floats/f128.rs
@@ -1,11 +1,11 @@
 // FIXME(f16_f128): only tested on platforms that have symbols and aren't buggy
 #![cfg(reliable_f128)]
 
-use crate::f128::consts;
-use crate::num::FpCategory as Fp;
+use std::f128::consts;
+use std::num::FpCategory as Fp;
 #[cfg(reliable_f128_math)]
-use crate::ops::Rem;
-use crate::ops::{Add, Div, Mul, Sub};
+use std::ops::Rem;
+use std::ops::{Add, Div, Mul, Sub};
 
 // Note these tolerances make sense around zero, but not for more extreme exponents.
 
@@ -762,8 +762,6 @@ fn test_ln_gamma() {
 
 #[test]
 fn test_real_consts() {
-    use super::consts;
-
     let pi: f128 = consts::PI;
     let frac_pi_2: f128 = consts::FRAC_PI_2;
     let frac_pi_3: f128 = consts::FRAC_PI_3;
diff --git a/library/std/src/f16/tests.rs b/library/std/tests/floats/f16.rs
similarity index 99%
rename from library/std/src/f16/tests.rs
rename to library/std/tests/floats/f16.rs
index 684ee3f3855b8..5180f3d40f3a7 100644
--- a/library/std/src/f16/tests.rs
+++ b/library/std/tests/floats/f16.rs
@@ -1,8 +1,8 @@
 // FIXME(f16_f128): only tested on platforms that have symbols and aren't buggy
 #![cfg(reliable_f16)]
 
-use crate::f16::consts;
-use crate::num::{FpCategory as Fp, *};
+use std::f16::consts;
+use std::num::FpCategory as Fp;
 
 /// Tolerance for results on the order of 10.0e-2
 #[allow(unused)]
@@ -54,7 +54,7 @@ macro_rules! assert_f16_biteq {
 
 #[test]
 fn test_num_f16() {
-    test_num(10f16, 2f16);
+    crate::test_num(10f16, 2f16);
 }
 
 #[test]
@@ -734,7 +734,6 @@ fn test_ln_gamma() {
 #[test]
 fn test_real_consts() {
     // FIXME(f16_f128): add math tests when available
-    use super::consts;
 
     let pi: f16 = consts::PI;
     let frac_pi_2: f16 = consts::FRAC_PI_2;
diff --git a/library/std/src/f32/tests.rs b/library/std/tests/floats/f32.rs
similarity index 99%
rename from library/std/src/f32/tests.rs
rename to library/std/tests/floats/f32.rs
index 99cfcfb231dad..bf7641986ada8 100644
--- a/library/std/src/f32/tests.rs
+++ b/library/std/tests/floats/f32.rs
@@ -1,5 +1,5 @@
-use crate::f32::consts;
-use crate::num::{FpCategory as Fp, *};
+use std::f32::consts;
+use std::num::FpCategory as Fp;
 
 /// Smallest number
 const TINY_BITS: u32 = 0x1;
@@ -35,7 +35,7 @@ macro_rules! assert_f32_biteq {
 
 #[test]
 fn test_num_f32() {
-    test_num(10f32, 2f32);
+    crate::test_num(10f32, 2f32);
 }
 
 #[test]
@@ -700,8 +700,6 @@ fn test_ln_gamma() {
 
 #[test]
 fn test_real_consts() {
-    use super::consts;
-
     let pi: f32 = consts::PI;
     let frac_pi_2: f32 = consts::FRAC_PI_2;
     let frac_pi_3: f32 = consts::FRAC_PI_3;
diff --git a/library/std/src/f64/tests.rs b/library/std/tests/floats/f64.rs
similarity index 99%
rename from library/std/src/f64/tests.rs
rename to library/std/tests/floats/f64.rs
index f5ba2c7b594e9..cbbfcd15efd26 100644
--- a/library/std/src/f64/tests.rs
+++ b/library/std/tests/floats/f64.rs
@@ -1,5 +1,5 @@
-use crate::f64::consts;
-use crate::num::{FpCategory as Fp, *};
+use std::f64::consts;
+use std::num::FpCategory as Fp;
 
 /// Smallest number
 const TINY_BITS: u64 = 0x1;
@@ -35,7 +35,7 @@ macro_rules! assert_f64_biteq {
 
 #[test]
 fn test_num_f64() {
-    test_num(10f64, 2f64);
+    crate::test_num(10f64, 2f64);
 }
 
 #[test]
@@ -680,7 +680,6 @@ fn test_ln_gamma() {
 
 #[test]
 fn test_real_consts() {
-    use super::consts;
     let pi: f64 = consts::PI;
     let frac_pi_2: f64 = consts::FRAC_PI_2;
     let frac_pi_3: f64 = consts::FRAC_PI_3;
diff --git a/library/std/tests/floats/lib.rs b/library/std/tests/floats/lib.rs
new file mode 100644
index 0000000000000..ad82f1a44e711
--- /dev/null
+++ b/library/std/tests/floats/lib.rs
@@ -0,0 +1,42 @@
+#![feature(f16, f128, float_gamma, float_minimum_maximum)]
+
+use std::fmt;
+use std::ops::{Add, Div, Mul, Rem, Sub};
+
+/// Verify that floats are within a tolerance of each other, 1.0e-6 by default.
+macro_rules! assert_approx_eq {
+    ($a:expr, $b:expr) => {{ assert_approx_eq!($a, $b, 1.0e-6) }};
+    ($a:expr, $b:expr, $lim:expr) => {{
+        let (a, b) = (&$a, &$b);
+        let diff = (*a - *b).abs();
+        assert!(
+            diff < $lim,
+            "{a:?} is not approximately equal to {b:?} (threshold {lim:?}, difference {diff:?})",
+            lim = $lim
+        );
+    }};
+}
+
+/// Helper function for testing numeric operations
+pub fn test_num<T>(ten: T, two: T)
+where
+    T: PartialEq
+        + Add<Output = T>
+        + Sub<Output = T>
+        + Mul<Output = T>
+        + Div<Output = T>
+        + Rem<Output = T>
+        + fmt::Debug
+        + Copy,
+{
+    assert_eq!(ten.add(two), ten + two);
+    assert_eq!(ten.sub(two), ten - two);
+    assert_eq!(ten.mul(two), ten * two);
+    assert_eq!(ten.div(two), ten / two);
+    assert_eq!(ten.rem(two), ten % two);
+}
+
+mod f128;
+mod f16;
+mod f32;
+mod f64;
diff --git a/library/std/src/num/tests.rs b/library/std/tests/num.rs
similarity index 98%
rename from library/std/src/num/tests.rs
rename to library/std/tests/num.rs
index df0df3f23f756..a7400f1c02df0 100644
--- a/library/std/src/num/tests.rs
+++ b/library/std/tests/num.rs
@@ -1,4 +1,4 @@
-use crate::ops::Mul;
+use std::ops::Mul;
 
 #[test]
 fn test_saturating_add_uint() {
@@ -190,8 +190,8 @@ fn test_uint_to_str_overflow() {
     assert_eq!(u64_val.to_string(), "0");
 }
 
-fn from_str<T: crate::str::FromStr>(t: &str) -> Option<T> {
-    crate::str::FromStr::from_str(t).ok()
+fn from_str<T: std::str::FromStr>(t: &str) -> Option<T> {
+    std::str::FromStr::from_str(t).ok()
 }
 
 #[test]
diff --git a/library/std/src/panic/tests.rs b/library/std/tests/panic.rs
similarity index 89%
rename from library/std/src/panic/tests.rs
rename to library/std/tests/panic.rs
index b37d74011cc67..f13b931dd222e 100644
--- a/library/std/src/panic/tests.rs
+++ b/library/std/tests/panic.rs
@@ -1,9 +1,9 @@
 #![allow(dead_code)]
 
-use crate::cell::RefCell;
-use crate::panic::{AssertUnwindSafe, UnwindSafe};
-use crate::rc::Rc;
-use crate::sync::{Arc, Mutex, RwLock};
+use std::cell::RefCell;
+use std::panic::{AssertUnwindSafe, UnwindSafe};
+use std::rc::Rc;
+use std::sync::{Arc, Mutex, RwLock};
 
 struct Foo {
     a: i32,
diff --git a/library/std/src/path/tests.rs b/library/std/tests/path.rs
similarity index 93%
rename from library/std/src/path/tests.rs
rename to library/std/tests/path.rs
index 3f96ac4672aff..978402b6fdaea 100644
--- a/library/std/src/path/tests.rs
+++ b/library/std/tests/path.rs
@@ -1,10 +1,19 @@
-use core::hint::black_box;
-
-use super::*;
-use crate::collections::{BTreeSet, HashSet};
-use crate::hash::DefaultHasher;
-use crate::mem::MaybeUninit;
-use crate::ptr;
+#![feature(
+    clone_to_uninit,
+    path_add_extension,
+    path_file_prefix,
+    maybe_uninit_slice,
+    os_string_pathbuf_leak
+)]
+
+use std::clone::CloneToUninit;
+use std::ffi::OsStr;
+use std::hash::{DefaultHasher, Hash, Hasher};
+use std::mem::MaybeUninit;
+use std::path::*;
+use std::ptr;
+use std::rc::Rc;
+use std::sync::Arc;
 
 #[allow(unknown_lints, unused_macro_rules)]
 macro_rules! t (
@@ -110,7 +119,7 @@ macro_rules! t (
 
 #[test]
 fn into() {
-    use crate::borrow::Cow;
+    use std::borrow::Cow;
 
     let static_path = Path::new("/home/foo");
     let static_cow_path: Cow<'static, Path> = static_path.into();
@@ -1525,7 +1534,7 @@ pub fn test_with_added_extension() {
 
 #[test]
 fn test_eq_receivers() {
-    use crate::borrow::Cow;
+    use std::borrow::Cow;
 
     let borrowed: &Path = Path::new("foo/bar");
     let mut owned: PathBuf = PathBuf::new();
@@ -1550,7 +1559,7 @@ fn test_eq_receivers() {
 
 #[test]
 pub fn test_compare() {
-    use crate::hash::{DefaultHasher, Hash, Hasher};
+    use std::hash::{DefaultHasher, Hash, Hasher};
 
     fn hash<T: Hash>(t: T) -> u64 {
         let mut s = DefaultHasher::new();
@@ -1867,12 +1876,12 @@ fn test_ord() {
 #[test]
 #[cfg(any(unix, target_os = "wasi"))]
 fn test_unix_absolute() {
-    use crate::path::absolute;
+    use std::path::absolute;
 
     assert!(absolute("").is_err());
 
     let relative = "a/b";
-    let mut expected = crate::env::current_dir().unwrap();
+    let mut expected = std::env::current_dir().unwrap();
     expected.push(relative);
     assert_eq!(absolute(relative).unwrap().as_os_str(), expected.as_os_str());
 
@@ -1888,7 +1897,7 @@ fn test_unix_absolute() {
     );
 
     // Test leading `.` and `..` components
-    let curdir = crate::env::current_dir().unwrap();
+    let curdir = std::env::current_dir().unwrap();
     assert_eq!(absolute("./a").unwrap().as_os_str(), curdir.join("a").as_os_str());
     assert_eq!(absolute("../a").unwrap().as_os_str(), curdir.join("../a").as_os_str()); // return /pwd/../a
 }
@@ -1896,12 +1905,12 @@ fn test_unix_absolute() {
 #[test]
 #[cfg(windows)]
 fn test_windows_absolute() {
-    use crate::path::absolute;
+    use std::path::absolute;
     // An empty path is an error.
     assert!(absolute("").is_err());
 
     let relative = r"a\b";
-    let mut expected = crate::env::current_dir().unwrap();
+    let mut expected = std::env::current_dir().unwrap();
     expected.push(relative);
     assert_eq!(absolute(relative).unwrap().as_os_str(), expected.as_os_str());
 
@@ -1953,116 +1962,6 @@ fn test_extension_path_sep_alternate() {
     assert_eq!(path, Path::new("path/to/file.d\\test"));
 }
 
-#[bench]
-#[cfg_attr(miri, ignore)] // Miri isn't fast...
-fn bench_path_cmp_fast_path_buf_sort(b: &mut test::Bencher) {
-    let prefix = "my/home";
-    let mut paths: Vec<_> =
-        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
-
-    paths.sort();
-
-    b.iter(|| {
-        black_box(paths.as_mut_slice()).sort_unstable();
-    });
-}
-
-#[bench]
-#[cfg_attr(miri, ignore)] // Miri isn't fast...
-fn bench_path_cmp_fast_path_long(b: &mut test::Bencher) {
-    let prefix = "/my/home/is/my/castle/and/my/castle/has/a/rusty/workbench/";
-    let paths: Vec<_> =
-        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
-
-    let mut set = BTreeSet::new();
-
-    paths.iter().for_each(|p| {
-        set.insert(p.as_path());
-    });
-
-    b.iter(|| {
-        set.remove(paths[500].as_path());
-        set.insert(paths[500].as_path());
-    });
-}
-
-#[bench]
-#[cfg_attr(miri, ignore)] // Miri isn't fast...
-fn bench_path_cmp_fast_path_short(b: &mut test::Bencher) {
-    let prefix = "my/home";
-    let paths: Vec<_> =
-        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
-
-    let mut set = BTreeSet::new();
-
-    paths.iter().for_each(|p| {
-        set.insert(p.as_path());
-    });
-
-    b.iter(|| {
-        set.remove(paths[500].as_path());
-        set.insert(paths[500].as_path());
-    });
-}
-
-#[bench]
-#[cfg_attr(miri, ignore)] // Miri isn't fast...
-fn bench_path_hashset(b: &mut test::Bencher) {
-    let prefix = "/my/home/is/my/castle/and/my/castle/has/a/rusty/workbench/";
-    let paths: Vec<_> =
-        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
-
-    let mut set = HashSet::new();
-
-    paths.iter().for_each(|p| {
-        set.insert(p.as_path());
-    });
-
-    b.iter(|| {
-        set.remove(paths[500].as_path());
-        set.insert(black_box(paths[500].as_path()))
-    });
-}
-
-#[bench]
-#[cfg_attr(miri, ignore)] // Miri isn't fast...
-fn bench_path_hashset_miss(b: &mut test::Bencher) {
-    let prefix = "/my/home/is/my/castle/and/my/castle/has/a/rusty/workbench/";
-    let paths: Vec<_> =
-        (0..1000).map(|num| PathBuf::from(prefix).join(format!("file {num}.rs"))).collect();
-
-    let mut set = HashSet::new();
-
-    paths.iter().for_each(|p| {
-        set.insert(p.as_path());
-    });
-
-    let probe = PathBuf::from(prefix).join("other");
-
-    b.iter(|| set.remove(black_box(probe.as_path())));
-}
-
-#[bench]
-fn bench_hash_path_short(b: &mut test::Bencher) {
-    let mut hasher = DefaultHasher::new();
-    let path = Path::new("explorer.exe");
-
-    b.iter(|| black_box(path).hash(&mut hasher));
-
-    black_box(hasher.finish());
-}
-
-#[bench]
-fn bench_hash_path_long(b: &mut test::Bencher) {
-    let mut hasher = DefaultHasher::new();
-    let path =
-        Path::new("/aaaaa/aaaaaa/./../aaaaaaaa/bbbbbbbbbbbbb/ccccccccccc/ddddddddd/eeeeeee.fff");
-
-    b.iter(|| black_box(path).hash(&mut hasher));
-
-    black_box(hasher.finish());
-}
-
 #[test]
 fn clone_to_uninit() {
     let a = Path::new("hello.txt");
diff --git a/library/std/src/sync/barrier/tests.rs b/library/std/tests/sync/barrier.rs
similarity index 89%
rename from library/std/src/sync/barrier/tests.rs
rename to library/std/tests/sync/barrier.rs
index 0fbcd9988127b..8aefff9d5071c 100644
--- a/library/std/src/sync/barrier/tests.rs
+++ b/library/std/tests/sync/barrier.rs
@@ -1,6 +1,6 @@
-use crate::sync::mpsc::{TryRecvError, channel};
-use crate::sync::{Arc, Barrier};
-use crate::thread;
+use std::sync::mpsc::{TryRecvError, channel};
+use std::sync::{Arc, Barrier};
+use std::thread;
 
 #[test]
 #[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
diff --git a/library/std/src/sync/poison/condvar/tests.rs b/library/std/tests/sync/condvar.rs
similarity index 97%
rename from library/std/src/sync/poison/condvar/tests.rs
rename to library/std/tests/sync/condvar.rs
index f9e9066bc92a2..834de6bb1c295 100644
--- a/library/std/src/sync/poison/condvar/tests.rs
+++ b/library/std/tests/sync/condvar.rs
@@ -1,8 +1,8 @@
-use crate::sync::atomic::{AtomicBool, Ordering};
-use crate::sync::mpsc::channel;
-use crate::sync::{Arc, Condvar, Mutex};
-use crate::thread;
-use crate::time::Duration;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::mpsc::channel;
+use std::sync::{Arc, Condvar, Mutex};
+use std::thread;
+use std::time::Duration;
 
 #[test]
 fn smoke() {
diff --git a/library/std/src/sync/lazy_lock/tests.rs b/library/std/tests/sync/lazy_lock.rs
similarity index 93%
rename from library/std/src/sync/lazy_lock/tests.rs
rename to library/std/tests/sync/lazy_lock.rs
index 7d7dde5434990..6c14b79f2ce7c 100644
--- a/library/std/src/sync/lazy_lock/tests.rs
+++ b/library/std/tests/sync/lazy_lock.rs
@@ -1,8 +1,8 @@
-use crate::cell::LazyCell;
-use crate::sync::atomic::AtomicUsize;
-use crate::sync::atomic::Ordering::SeqCst;
-use crate::sync::{LazyLock, Mutex, OnceLock};
-use crate::{panic, thread};
+use std::cell::LazyCell;
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering::SeqCst;
+use std::sync::{LazyLock, Mutex, OnceLock};
+use std::{panic, thread};
 
 fn spawn_and_wait<R: Send + 'static>(f: impl FnOnce() -> R + Send + 'static) -> R {
     thread::spawn(f).join().unwrap()
@@ -149,7 +149,7 @@ fn is_sync_send() {
 #[should_panic = "has previously been poisoned"]
 fn lazy_force_mut_panic() {
     let mut lazy = LazyLock::<String>::new(|| panic!());
-    crate::panic::catch_unwind(crate::panic::AssertUnwindSafe(|| {
+    panic::catch_unwind(panic::AssertUnwindSafe(|| {
         let _ = LazyLock::force_mut(&mut lazy);
     }))
     .unwrap_err();
diff --git a/library/std/tests/sync/lib.rs b/library/std/tests/sync/lib.rs
new file mode 100644
index 0000000000000..6bf320d52f21a
--- /dev/null
+++ b/library/std/tests/sync/lib.rs
@@ -0,0 +1,32 @@
+#![feature(lazy_get)]
+#![feature(mapped_lock_guards)]
+#![feature(mpmc_channel)]
+#![feature(once_cell_try)]
+#![feature(once_wait)]
+#![feature(lock_value_accessors)]
+#![feature(reentrant_lock)]
+#![feature(rwlock_downgrade)]
+#![feature(std_internals)]
+#![allow(internal_features)]
+
+mod barrier;
+mod condvar;
+mod lazy_lock;
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod mpmc;
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod mpsc;
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod mpsc_sync;
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod mutex;
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod once;
+mod once_lock;
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod reentrant_lock;
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod rwlock;
+
+#[path = "../common/mod.rs"]
+mod common;
diff --git a/library/std/src/sync/mpmc/tests.rs b/library/std/tests/sync/mpmc.rs
similarity index 99%
rename from library/std/src/sync/mpmc/tests.rs
rename to library/std/tests/sync/mpmc.rs
index ab14050df6c98..81b92297f76a3 100644
--- a/library/std/src/sync/mpmc/tests.rs
+++ b/library/std/tests/sync/mpmc.rs
@@ -1,5 +1,6 @@
-use super::*;
-use crate::{env, thread};
+use std::sync::mpmc::*;
+use std::time::{Duration, Instant};
+use std::{env, thread};
 
 pub fn stress_factor() -> usize {
     match env::var("RUST_TEST_STRESS") {
diff --git a/library/std/src/sync/mpsc/tests.rs b/library/std/tests/sync/mpsc.rs
similarity index 99%
rename from library/std/src/sync/mpsc/tests.rs
rename to library/std/tests/sync/mpsc.rs
index 13892fa0d18e4..1d8edfde44bed 100644
--- a/library/std/src/sync/mpsc/tests.rs
+++ b/library/std/tests/sync/mpsc.rs
@@ -1,5 +1,6 @@
-use super::*;
-use crate::{env, thread};
+use std::sync::mpsc::*;
+use std::time::{Duration, Instant};
+use std::{env, thread};
 
 pub fn stress_factor() -> usize {
     match env::var("RUST_TEST_STRESS") {
diff --git a/library/std/src/sync/mpsc/sync_tests.rs b/library/std/tests/sync/mpsc_sync.rs
similarity index 99%
rename from library/std/src/sync/mpsc/sync_tests.rs
rename to library/std/tests/sync/mpsc_sync.rs
index 49b65c8efe692..a7f326d201b00 100644
--- a/library/std/src/sync/mpsc/sync_tests.rs
+++ b/library/std/tests/sync/mpsc_sync.rs
@@ -1,7 +1,8 @@
-use super::*;
-use crate::rc::Rc;
-use crate::sync::mpmc::SendTimeoutError;
-use crate::{env, thread};
+use std::rc::Rc;
+use std::sync::mpmc::SendTimeoutError;
+use std::sync::mpsc::*;
+use std::time::Duration;
+use std::{env, thread};
 
 pub fn stress_factor() -> usize {
     match env::var("RUST_TEST_STRESS") {
diff --git a/library/std/src/sync/poison/mutex/tests.rs b/library/std/tests/sync/mutex.rs
similarity index 97%
rename from library/std/src/sync/poison/mutex/tests.rs
rename to library/std/tests/sync/mutex.rs
index 395c8aada089a..74c627201073e 100644
--- a/library/std/src/sync/poison/mutex/tests.rs
+++ b/library/std/tests/sync/mutex.rs
@@ -1,10 +1,10 @@
-use crate::fmt::Debug;
-use crate::ops::FnMut;
-use crate::panic::{self, AssertUnwindSafe};
-use crate::sync::atomic::{AtomicUsize, Ordering};
-use crate::sync::mpsc::channel;
-use crate::sync::{Arc, Condvar, MappedMutexGuard, Mutex, MutexGuard, TryLockError};
-use crate::{hint, mem, thread};
+use std::fmt::Debug;
+use std::ops::FnMut;
+use std::panic::{self, AssertUnwindSafe};
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::mpsc::channel;
+use std::sync::{Arc, Condvar, MappedMutexGuard, Mutex, MutexGuard, TryLockError};
+use std::{hint, mem, thread};
 
 struct Packet<T>(Arc<(Mutex<T>, Condvar)>);
 
diff --git a/library/std/src/sync/poison/once/tests.rs b/library/std/tests/sync/once.rs
similarity index 94%
rename from library/std/src/sync/poison/once/tests.rs
rename to library/std/tests/sync/once.rs
index ce96468aeb6e1..a3ffc73fe06b9 100644
--- a/library/std/src/sync/poison/once/tests.rs
+++ b/library/std/tests/sync/once.rs
@@ -1,9 +1,9 @@
-use super::Once;
-use crate::sync::atomic::AtomicBool;
-use crate::sync::atomic::Ordering::Relaxed;
-use crate::sync::mpsc::channel;
-use crate::time::Duration;
-use crate::{panic, thread};
+use std::sync::Once;
+use std::sync::atomic::AtomicBool;
+use std::sync::atomic::Ordering::Relaxed;
+use std::sync::mpsc::channel;
+use std::time::Duration;
+use std::{panic, thread};
 
 #[test]
 fn smoke_once() {
diff --git a/library/std/src/sync/once_lock/tests.rs b/library/std/tests/sync/once_lock.rs
similarity index 91%
rename from library/std/src/sync/once_lock/tests.rs
rename to library/std/tests/sync/once_lock.rs
index 5113d436c3c99..ac9aaa8892eff 100644
--- a/library/std/src/sync/once_lock/tests.rs
+++ b/library/std/tests/sync/once_lock.rs
@@ -1,8 +1,8 @@
-use crate::sync::OnceLock;
-use crate::sync::atomic::AtomicUsize;
-use crate::sync::atomic::Ordering::SeqCst;
-use crate::sync::mpsc::channel;
-use crate::{panic, thread};
+use std::sync::OnceLock;
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering::SeqCst;
+use std::sync::mpsc::channel;
+use std::{panic, thread};
 
 fn spawn_and_wait<R: Send + 'static>(f: impl FnOnce() -> R + Send + 'static) -> R {
     thread::spawn(f).join().unwrap()
@@ -33,15 +33,6 @@ fn sync_once_cell_get_mut() {
     assert_eq!(c.get_mut(), Some(&mut 92));
 }
 
-#[test]
-fn sync_once_cell_get_unchecked() {
-    let c = OnceLock::new();
-    c.set(92).unwrap();
-    unsafe {
-        assert_eq!(c.get_unchecked(), &92);
-    }
-}
-
 #[test]
 #[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn sync_once_cell_drop() {
@@ -88,7 +79,6 @@ fn get_or_try_init() {
 
     let res = panic::catch_unwind(|| cell.get_or_try_init(|| -> Result<_, ()> { panic!() }));
     assert!(res.is_err());
-    assert!(!cell.is_initialized());
     assert!(cell.get().is_none());
 
     assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
@@ -174,7 +164,7 @@ fn sync_once_cell_does_not_leak_partially_constructed_boxes() {
                     break;
                 }
                 #[cfg(target_env = "sgx")]
-                crate::thread::yield_now();
+                std::thread::yield_now();
             }
         });
     }
diff --git a/library/std/src/sync/reentrant_lock/tests.rs b/library/std/tests/sync/reentrant_lock.rs
similarity index 91%
rename from library/std/src/sync/reentrant_lock/tests.rs
rename to library/std/tests/sync/reentrant_lock.rs
index aeef0289d28f8..2b7b87e36234a 100644
--- a/library/std/src/sync/reentrant_lock/tests.rs
+++ b/library/std/tests/sync/reentrant_lock.rs
@@ -1,7 +1,6 @@
-use super::ReentrantLock;
-use crate::cell::RefCell;
-use crate::sync::Arc;
-use crate::thread;
+use std::cell::RefCell;
+use std::sync::{Arc, ReentrantLock};
+use std::thread;
 
 #[test]
 fn smoke() {
diff --git a/library/std/src/sync/poison/rwlock/tests.rs b/library/std/tests/sync/rwlock.rs
similarity index 98%
rename from library/std/src/sync/poison/rwlock/tests.rs
rename to library/std/tests/sync/rwlock.rs
index 057c2f1a5d7a7..bd4bc7a14bc8e 100644
--- a/library/std/src/sync/poison/rwlock/tests.rs
+++ b/library/std/tests/sync/rwlock.rs
@@ -1,15 +1,15 @@
-use rand::Rng;
-
-use crate::fmt::Debug;
-use crate::ops::FnMut;
-use crate::panic::{self, AssertUnwindSafe};
-use crate::sync::atomic::{AtomicUsize, Ordering};
-use crate::sync::mpsc::channel;
-use crate::sync::{
+use std::fmt::Debug;
+use std::ops::FnMut;
+use std::panic::{self, AssertUnwindSafe};
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::mpsc::channel;
+use std::sync::{
     Arc, MappedRwLockReadGuard, MappedRwLockWriteGuard, RwLock, RwLockReadGuard, RwLockWriteGuard,
     TryLockError,
 };
-use crate::{hint, mem, thread};
+use std::{hint, mem, thread};
+
+use rand::Rng;
 
 #[derive(Eq, PartialEq, Debug)]
 struct NonCopy(i32);
@@ -57,7 +57,7 @@ fn frob() {
         let tx = tx.clone();
         let r = r.clone();
         thread::spawn(move || {
-            let mut rng = crate::test_helpers::test_rng();
+            let mut rng = crate::common::test_rng();
             for _ in 0..M {
                 if rng.gen_bool(1.0 / (N as f64)) {
                     drop(r.write().unwrap());
@@ -704,7 +704,7 @@ fn test_downgrade_atomic() {
 
     // Wait for a good amount of time so that evil threads go to sleep.
     // Note: this is not strictly necessary...
-    let eternity = crate::time::Duration::from_millis(42);
+    let eternity = std::time::Duration::from_millis(42);
     thread::sleep(eternity);
 
     // Once everyone is asleep, set the value to `NEW_VALUE`.
diff --git a/library/std/src/thread/local/dynamic_tests.rs b/library/std/tests/thread_local/dynamic_tests.rs
similarity index 89%
rename from library/std/src/thread/local/dynamic_tests.rs
rename to library/std/tests/thread_local/dynamic_tests.rs
index dd18004164824..454462b392510 100644
--- a/library/std/src/thread/local/dynamic_tests.rs
+++ b/library/std/tests/thread_local/dynamic_tests.rs
@@ -1,6 +1,6 @@
-use crate::cell::RefCell;
-use crate::collections::HashMap;
-use crate::thread_local;
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::thread_local;
 
 #[test]
 fn smoke() {
diff --git a/library/std/tests/thread_local/lib.rs b/library/std/tests/thread_local/lib.rs
new file mode 100644
index 0000000000000..c52914354253c
--- /dev/null
+++ b/library/std/tests/thread_local/lib.rs
@@ -0,0 +1,4 @@
+#[cfg(not(any(target_os = "emscripten", target_os = "wasi")))]
+mod tests;
+
+mod dynamic_tests;
diff --git a/library/std/src/thread/local/tests.rs b/library/std/tests/thread_local/tests.rs
similarity index 98%
rename from library/std/src/thread/local/tests.rs
rename to library/std/tests/thread_local/tests.rs
index 9d4f52a09218e..aa020c2559cc5 100644
--- a/library/std/src/thread/local/tests.rs
+++ b/library/std/tests/thread_local/tests.rs
@@ -1,8 +1,8 @@
-use crate::cell::{Cell, UnsafeCell};
-use crate::sync::atomic::{AtomicU8, Ordering};
-use crate::sync::{Arc, Condvar, Mutex};
-use crate::thread::{self, Builder, LocalKey};
-use crate::thread_local;
+use std::cell::{Cell, UnsafeCell};
+use std::sync::atomic::{AtomicU8, Ordering};
+use std::sync::{Arc, Condvar, Mutex};
+use std::thread::{self, Builder, LocalKey};
+use std::thread_local;
 
 #[derive(Clone, Default)]
 struct Signal(Arc<(Mutex<bool>, Condvar)>);
diff --git a/library/std/src/time/tests.rs b/library/std/tests/time.rs
similarity index 81%
rename from library/std/src/time/tests.rs
rename to library/std/tests/time.rs
index e88f2d5e80676..40709eae37cfc 100644
--- a/library/std/src/time/tests.rs
+++ b/library/std/tests/time.rs
@@ -1,9 +1,7 @@
-use core::fmt::Debug;
+#![feature(duration_constants)]
 
-#[cfg(not(target_arch = "wasm32"))]
-use test::{Bencher, black_box};
-
-use super::{Duration, Instant, SystemTime, UNIX_EPOCH};
+use std::fmt::Debug;
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 
 macro_rules! assert_almost_eq {
     ($a:expr, $b:expr) => {{
@@ -29,10 +27,10 @@ fn instant_monotonic() {
 
 #[test]
 #[cfg(not(target_arch = "wasm32"))]
-fn instant_monotonic_concurrent() -> crate::thread::Result<()> {
+fn instant_monotonic_concurrent() -> std::thread::Result<()> {
     let threads: Vec<_> = (0..8)
         .map(|_| {
-            crate::thread::spawn(|| {
+            std::thread::spawn(|| {
                 let mut old = Instant::now();
                 let count = if cfg!(miri) { 1_000 } else { 5_000_000 };
                 for _ in 0..count {
@@ -229,46 +227,3 @@ fn big_math() {
     check(instant.checked_add(Duration::from_secs(100)), Instant::checked_sub);
     check(instant.checked_add(Duration::from_secs(i64::MAX as _)), Instant::checked_sub);
 }
-
-macro_rules! bench_instant_threaded {
-    ($bench_name:ident, $thread_count:expr) => {
-        #[bench]
-        #[cfg(not(target_arch = "wasm32"))]
-        fn $bench_name(b: &mut Bencher) -> crate::thread::Result<()> {
-            use crate::sync::Arc;
-            use crate::sync::atomic::{AtomicBool, Ordering};
-
-            let running = Arc::new(AtomicBool::new(true));
-
-            let threads: Vec<_> = (0..$thread_count)
-                .map(|_| {
-                    let flag = Arc::clone(&running);
-                    crate::thread::spawn(move || {
-                        while flag.load(Ordering::Relaxed) {
-                            black_box(Instant::now());
-                        }
-                    })
-                })
-                .collect();
-
-            b.iter(|| {
-                let a = Instant::now();
-                let b = Instant::now();
-                assert!(b >= a);
-            });
-
-            running.store(false, Ordering::Relaxed);
-
-            for t in threads {
-                t.join()?;
-            }
-            Ok(())
-        }
-    };
-}
-
-bench_instant_threaded!(instant_contention_01_threads, 0);
-bench_instant_threaded!(instant_contention_02_threads, 1);
-bench_instant_threaded!(instant_contention_04_threads, 3);
-bench_instant_threaded!(instant_contention_08_threads, 7);
-bench_instant_threaded!(instant_contention_16_threads, 15);
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 6e817af0d6e0c..a44d74e6df678 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -5,9 +5,7 @@ use std::{fmt, iter};
 
 use arrayvec::ArrayVec;
 use rustc_abi::{ExternAbi, VariantIdx};
-use rustc_attr_parsing::{
-    AllowedThroughUnstableModules, ConstStability, Deprecation, Stability, StableSince,
-};
+use rustc_attr_parsing::{ConstStability, Deprecation, Stability, StableSince};
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE, LocalDefId};
@@ -411,15 +409,9 @@ impl Item {
                 ..
             } = stab.level
             {
-                let note = match note {
-                    AllowedThroughUnstableModules::WithDeprecation(note) => Some(note),
-                    // FIXME: Would be better to say *something* here about the *path* being
-                    // deprecated rather than the item.
-                    AllowedThroughUnstableModules::WithoutDeprecation => None,
-                };
                 Some(Deprecation {
                     since: rustc_attr_parsing::DeprecatedSince::Unspecified,
-                    note,
+                    note: Some(note),
                     suggestion: None,
                 })
             } else {
diff --git a/src/tools/clippy/book/src/development/adding_lints.md b/src/tools/clippy/book/src/development/adding_lints.md
index c26ad319f4f5d..48506127dee40 100644
--- a/src/tools/clippy/book/src/development/adding_lints.md
+++ b/src/tools/clippy/book/src/development/adding_lints.md
@@ -788,7 +788,7 @@ don't hesitate to ask on [Zulip] or in the issue/PR.
 [`snippet`]: https://doc.rust-lang.org/nightly/nightly-rustc/clippy_utils/source/fn.snippet.html
 [let-chains]: https://github.com/rust-lang/rust/pull/94927
 [from_expansion]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/struct.Span.html#method.from_expansion
-[in_external_macro]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/lint/fn.in_external_macro.html
+[in_external_macro]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/struct.Span.html#method.in_external_macro
 [span]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/struct.Span.html
 [applicability]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/enum.Applicability.html
 [rustc-dev-guide]: https://rustc-dev-guide.rust-lang.org/
diff --git a/src/tools/clippy/book/src/development/common_tools_writing_lints.md b/src/tools/clippy/book/src/development/common_tools_writing_lints.md
index b44ad80a25cc8..051febc2ca5da 100644
--- a/src/tools/clippy/book/src/development/common_tools_writing_lints.md
+++ b/src/tools/clippy/book/src/development/common_tools_writing_lints.md
@@ -218,7 +218,7 @@ functions to deal with macros:
   > context. And so just using `span.from_expansion()` is often good enough.
 
 
-- `in_external_macro(span)`: detect if the given span is from a macro defined in
+- `span.in_external_macro(sm)`: detect if the given span is from a macro defined in
   a foreign crate. If you want the lint to work with macro-generated code, this
   is the next line of defense to avoid macros not defined in the current crate.
   It doesn't make sense to lint code that the coder can't change.
@@ -227,15 +227,13 @@ functions to deal with macros:
   crates
 
   ```rust
-  use rustc_middle::lint::in_external_macro;
-
   use a_crate_with_macros::foo;
 
   // `foo` is defined in `a_crate_with_macros`
   foo!("bar");
 
   // if we lint the `match` of `foo` call and test its span
-  assert_eq!(in_external_macro(cx.sess(), match_span), true);
+  assert_eq!(match_span.in_external_macro(cx.sess().source_map()), true);
   ```
 
 - `span.ctxt()`: the span's context represents whether it is from expansion, and
diff --git a/src/tools/clippy/book/src/development/macro_expansions.md b/src/tools/clippy/book/src/development/macro_expansions.md
index 125b6c4bc5be1..36092f82e2607 100644
--- a/src/tools/clippy/book/src/development/macro_expansions.md
+++ b/src/tools/clippy/book/src/development/macro_expansions.md
@@ -120,7 +120,7 @@ assert_ne!(x_is_some_span.ctxt(), x_unwrap_span.ctxt());
 
 ### The `in_external_macro` function
 
-`rustc_middle::lint` provides a function ([`in_external_macro`]) that can
+`Span` provides a method ([`in_external_macro`]) that can
 detect if the given span is from a macro defined in a foreign crate.
 
 Therefore, if we really want a new lint to work with macro-generated code,
@@ -144,7 +144,7 @@ Also assume that we get the corresponding variable `foo_span` for the
 results in `true` (note that `cx` can be `EarlyContext` or `LateContext`):
 
 ```rust
-if in_external_macro(cx.sess(), foo_span) {
+if foo_span.in_external_macro(cx.sess().source_map()) {
     // We should ignore macro from a foreign crate.
     return;
 }
@@ -153,6 +153,6 @@ if in_external_macro(cx.sess(), foo_span) {
 [`ctxt`]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/struct.Span.html#method.ctxt
 [expansion]: https://rustc-dev-guide.rust-lang.org/macro-expansion.html#expansion-and-ast-integration
 [`from_expansion`]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/struct.Span.html#method.from_expansion
-[`in_external_macro`]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_middle/lint/fn.in_external_macro.html
+[`in_external_macro`]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/struct.Span.html#method.in_external_macro
 [Span]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/struct.Span.html
 [SyntaxContext]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/hygiene/struct.SyntaxContext.html
diff --git a/src/tools/clippy/clippy_lints/src/almost_complete_range.rs b/src/tools/clippy/clippy_lints/src/almost_complete_range.rs
index 2af5178920d9e..0f7f779e8ea71 100644
--- a/src/tools/clippy/clippy_lints/src/almost_complete_range.rs
+++ b/src/tools/clippy/clippy_lints/src/almost_complete_range.rs
@@ -5,7 +5,6 @@ use clippy_utils::source::{trim_span, walk_span_to_context};
 use rustc_ast::ast::{Expr, ExprKind, LitKind, Pat, PatKind, RangeEnd, RangeLimits};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 
 declare_clippy_lint! {
@@ -45,7 +44,7 @@ impl EarlyLintPass for AlmostCompleteRange {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) {
         if let ExprKind::Range(Some(start), Some(end), RangeLimits::HalfOpen) = &e.kind
             && is_incomplete_range(start, end)
-            && !in_external_macro(cx.sess(), e.span)
+            && !e.span.in_external_macro(cx.sess().source_map())
         {
             span_lint_and_then(
                 cx,
@@ -74,7 +73,7 @@ impl EarlyLintPass for AlmostCompleteRange {
         if let PatKind::Range(Some(start), Some(end), kind) = &p.kind
             && matches!(kind.node, RangeEnd::Excluded)
             && is_incomplete_range(start, end)
-            && !in_external_macro(cx.sess(), p.span)
+            && !p.span.in_external_macro(cx.sess().source_map())
         {
             span_lint_and_then(
                 cx,
diff --git a/src/tools/clippy/clippy_lints/src/arbitrary_source_item_ordering.rs b/src/tools/clippy/clippy_lints/src/arbitrary_source_item_ordering.rs
index 0389223c3e0fa..f519a65fc2721 100644
--- a/src/tools/clippy/clippy_lints/src/arbitrary_source_item_ordering.rs
+++ b/src/tools/clippy/clippy_lints/src/arbitrary_source_item_ordering.rs
@@ -9,7 +9,6 @@ use rustc_hir::{
     Variant, VariantData,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 
 declare_clippy_lint! {
@@ -248,7 +247,7 @@ impl<'tcx> LateLintPass<'tcx> for ArbitrarySourceItemOrdering {
             ItemKind::Enum(enum_def, _generics) if self.enable_ordering_for_enum => {
                 let mut cur_v: Option<&Variant<'_>> = None;
                 for variant in enum_def.variants {
-                    if in_external_macro(cx.sess(), variant.span) {
+                    if variant.span.in_external_macro(cx.sess().source_map()) {
                         continue;
                     }
 
@@ -263,7 +262,7 @@ impl<'tcx> LateLintPass<'tcx> for ArbitrarySourceItemOrdering {
             ItemKind::Struct(VariantData::Struct { fields, .. }, _generics) if self.enable_ordering_for_struct => {
                 let mut cur_f: Option<&FieldDef<'_>> = None;
                 for field in *fields {
-                    if in_external_macro(cx.sess(), field.span) {
+                    if field.span.in_external_macro(cx.sess().source_map()) {
                         continue;
                     }
 
@@ -281,7 +280,7 @@ impl<'tcx> LateLintPass<'tcx> for ArbitrarySourceItemOrdering {
                 let mut cur_t: Option<&TraitItemRef> = None;
 
                 for item in *item_ref {
-                    if in_external_macro(cx.sess(), item.span) {
+                    if item.span.in_external_macro(cx.sess().source_map()) {
                         continue;
                     }
 
@@ -304,7 +303,7 @@ impl<'tcx> LateLintPass<'tcx> for ArbitrarySourceItemOrdering {
                 let mut cur_t: Option<&ImplItemRef> = None;
 
                 for item in trait_impl.items {
-                    if in_external_macro(cx.sess(), item.span) {
+                    if item.span.in_external_macro(cx.sess().source_map()) {
                         continue;
                     }
 
@@ -348,7 +347,7 @@ impl<'tcx> LateLintPass<'tcx> for ArbitrarySourceItemOrdering {
         // as no sorting by source map/line of code has to be applied.
         //
         for item in items {
-            if in_external_macro(cx.sess(), item.span) {
+            if item.span.in_external_macro(cx.sess().source_map()) {
                 continue;
             }
 
diff --git a/src/tools/clippy/clippy_lints/src/as_conversions.rs b/src/tools/clippy/clippy_lints/src/as_conversions.rs
index fefd8195f8e7e..847653ed6e987 100644
--- a/src/tools/clippy/clippy_lints/src/as_conversions.rs
+++ b/src/tools/clippy/clippy_lints/src/as_conversions.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::is_from_proc_macro;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -49,7 +48,7 @@ declare_lint_pass!(AsConversions => [AS_CONVERSIONS]);
 impl<'tcx> LateLintPass<'tcx> for AsConversions {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'tcx>) {
         if let ExprKind::Cast(_, _) = expr.kind
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && !is_from_proc_macro(cx, expr)
         {
             #[expect(clippy::collapsible_span_lint_calls, reason = "rust-clippy#7797")]
diff --git a/src/tools/clippy/clippy_lints/src/attrs/allow_attributes.rs b/src/tools/clippy/clippy_lints/src/attrs/allow_attributes.rs
index 1879391ec290b..53d9725703c3d 100644
--- a/src/tools/clippy/clippy_lints/src/attrs/allow_attributes.rs
+++ b/src/tools/clippy/clippy_lints/src/attrs/allow_attributes.rs
@@ -4,11 +4,10 @@ use clippy_utils::is_from_proc_macro;
 use rustc_ast::{AttrStyle, Attribute};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 
 // Separate each crate's features.
 pub fn check<'cx>(cx: &EarlyContext<'cx>, attr: &'cx Attribute) {
-    if !in_external_macro(cx.sess(), attr.span)
+    if !attr.span.in_external_macro(cx.sess().source_map())
         && let AttrStyle::Outer = attr.style
         && let Some(ident) = attr.ident()
         && !is_from_proc_macro(cx, attr)
diff --git a/src/tools/clippy/clippy_lints/src/attrs/allow_attributes_without_reason.rs b/src/tools/clippy/clippy_lints/src/attrs/allow_attributes_without_reason.rs
index 788377fe83ce4..5bf077990e1fe 100644
--- a/src/tools/clippy/clippy_lints/src/attrs/allow_attributes_without_reason.rs
+++ b/src/tools/clippy/clippy_lints/src/attrs/allow_attributes_without_reason.rs
@@ -3,7 +3,6 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::is_from_proc_macro;
 use rustc_ast::{MetaItemInner, MetaItemKind};
 use rustc_lint::{EarlyContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_span::sym;
 use rustc_span::symbol::Symbol;
 
@@ -17,7 +16,7 @@ pub(super) fn check<'cx>(cx: &EarlyContext<'cx>, name: Symbol, items: &[MetaItem
     }
 
     // Check if the attribute is in an external macro and therefore out of the developer's control
-    if in_external_macro(cx.sess(), attr.span) || is_from_proc_macro(cx, attr) {
+    if attr.span.in_external_macro(cx.sess().source_map()) || is_from_proc_macro(cx, attr) {
         return;
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/attrs/useless_attribute.rs b/src/tools/clippy/clippy_lints/src/attrs/useless_attribute.rs
index e7158a6a6b6c7..e3e081ce08e9f 100644
--- a/src/tools/clippy/clippy_lints/src/attrs/useless_attribute.rs
+++ b/src/tools/clippy/clippy_lints/src/attrs/useless_attribute.rs
@@ -5,14 +5,13 @@ use clippy_utils::source::{SpanRangeExt, first_line_of_span};
 use rustc_ast::{Attribute, Item, ItemKind};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_span::sym;
 
 pub(super) fn check(cx: &EarlyContext<'_>, item: &Item, attrs: &[Attribute]) {
     let skip_unused_imports = attrs.iter().any(|attr| attr.has_name(sym::macro_use));
 
     for attr in attrs {
-        if in_external_macro(cx.sess(), attr.span) {
+        if attr.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
         if let Some(lint_list) = &attr.meta_item_list() {
diff --git a/src/tools/clippy/clippy_lints/src/blocks_in_conditions.rs b/src/tools/clippy/clippy_lints/src/blocks_in_conditions.rs
index eb05dc96cdebf..aab0af0d743b9 100644
--- a/src/tools/clippy/clippy_lints/src/blocks_in_conditions.rs
+++ b/src/tools/clippy/clippy_lints/src/blocks_in_conditions.rs
@@ -4,7 +4,6 @@ use clippy_utils::{higher, is_from_proc_macro};
 use rustc_errors::Applicability;
 use rustc_hir::{BlockCheckMode, Expr, ExprKind, MatchSource};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -54,7 +53,7 @@ const BRACED_EXPR_MESSAGE: &str = "omit braces around single expression conditio
 
 impl<'tcx> LateLintPass<'tcx> for BlocksInConditions {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if in_external_macro(cx.sess(), expr.span) {
+        if expr.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/box_default.rs b/src/tools/clippy/clippy_lints/src/box_default.rs
index 79fd6ffe46c33..3b861848f94a6 100644
--- a/src/tools/clippy/clippy_lints/src/box_default.rs
+++ b/src/tools/clippy/clippy_lints/src/box_default.rs
@@ -7,7 +7,6 @@ use rustc_hir::def::Res;
 use rustc_hir::intravisit::{InferKind, Visitor, VisitorExt, walk_ty};
 use rustc_hir::{AmbigArg, Block, Expr, ExprKind, HirId, LetStmt, Node, QPath, Ty, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::{Span, sym};
 
@@ -50,7 +49,7 @@ impl LateLintPass<'_> for BoxDefault {
             // This is the `T::default()` (or default equivalent) of `Box::new(T::default())`
             && let ExprKind::Call(arg_path, _) = arg.kind
             // And we are not in a foreign crate's macro
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             // And the argument expression has the same context as the outer call expression
             // or that we are inside a `vec!` macro expansion
             && (expr.span.eq_ctxt(arg.span) || is_local_vec_expn(cx, arg, expr))
diff --git a/src/tools/clippy/clippy_lints/src/casts/mod.rs b/src/tools/clippy/clippy_lints/src/casts/mod.rs
index d90cf124fe42a..521bd394901a6 100644
--- a/src/tools/clippy/clippy_lints/src/casts/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/mod.rs
@@ -29,7 +29,6 @@ use clippy_utils::is_hir_ty_cfg_dependant;
 use clippy_utils::msrvs::{self, Msrv};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 
 declare_clippy_lint! {
@@ -796,7 +795,7 @@ impl_lint_pass!(Casts => [
 
 impl<'tcx> LateLintPass<'tcx> for Casts {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if in_external_macro(cx.sess(), expr.span) {
+        if expr.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs b/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
index 9e1876e40f995..7885f171461d7 100644
--- a/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
@@ -8,7 +8,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Expr, ExprKind, Lit, Node, Path, QPath, TyKind, UnOp};
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, FloatTy, InferTy, Ty};
 use std::ops::ControlFlow;
 
@@ -142,7 +141,7 @@ pub(super) fn check<'tcx>(
         }
     }
 
-    if cast_from.kind() == cast_to.kind() && !in_external_macro(cx.sess(), expr.span) {
+    if cast_from.kind() == cast_to.kind() && !expr.span.in_external_macro(cx.sess().source_map()) {
         if let Some(id) = path_to_local(cast_expr)
             && !cx.tcx.hir().span(id).eq_ctxt(cast_expr.span)
         {
diff --git a/src/tools/clippy/clippy_lints/src/checked_conversions.rs b/src/tools/clippy/clippy_lints/src/checked_conversions.rs
index 1edfde974227e..9516af7334d7f 100644
--- a/src/tools/clippy/clippy_lints/src/checked_conversions.rs
+++ b/src/tools/clippy/clippy_lints/src/checked_conversions.rs
@@ -6,7 +6,6 @@ use clippy_utils::{SpanlessEq, is_in_const_context, is_integer_literal};
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, QPath, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 
 declare_clippy_lint! {
@@ -64,7 +63,7 @@ impl LateLintPass<'_> for CheckedConversions {
                 },
                 _ => return,
             }
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
             && !is_in_const_context(cx)
             && self.msrv.meets(msrvs::TRY_FROM)
             && let Some(cv) = match op2 {
diff --git a/src/tools/clippy/clippy_lints/src/dbg_macro.rs b/src/tools/clippy/clippy_lints/src/dbg_macro.rs
index a96c86f076574..06376c57119d5 100644
--- a/src/tools/clippy/clippy_lints/src/dbg_macro.rs
+++ b/src/tools/clippy/clippy_lints/src/dbg_macro.rs
@@ -7,7 +7,6 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, Node};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::{Span, SyntaxContext, sym};
 
@@ -60,7 +59,7 @@ impl LateLintPass<'_> for DbgMacro {
 
         if cur_syntax_ctxt != self.prev_ctxt &&
             let Some(macro_call) = first_dbg_macro_in_expansion(cx, expr.span) &&
-            !in_external_macro(cx.sess(), macro_call.span) &&
+            !macro_call.span.in_external_macro(cx.sess().source_map()) &&
             self.checked_dbg_call_site.insert(macro_call.span) &&
             // allows `dbg!` in test code if allow-dbg-in-test is set to true in clippy.toml
             !(self.allow_dbg_in_tests && is_in_test(cx.tcx, expr.hir_id))
diff --git a/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs b/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs
index ca3eaae7b85f3..772268e7899ef 100644
--- a/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs
+++ b/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs
@@ -9,7 +9,6 @@ use rustc_hir::{
     StructTailExpr,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, FloatTy, IntTy, PolyFnSig, Ty};
 use rustc_session::declare_lint_pass;
 use std::iter;
@@ -86,7 +85,7 @@ impl<'a, 'tcx> NumericFallbackVisitor<'a, 'tcx> {
 
     /// Check whether a passed literal has potential to cause fallback or not.
     fn check_lit(&self, lit: &Lit, lit_ty: Ty<'tcx>, emit_hir_id: HirId) {
-        if !in_external_macro(self.cx.sess(), lit.span)
+        if !lit.span.in_external_macro(self.cx.sess().source_map())
             && matches!(self.ty_bounds.last(), Some(ExplicitTyBound(false)))
             && matches!(
                 lit.node,
diff --git a/src/tools/clippy/clippy_lints/src/doc/mod.rs b/src/tools/clippy/clippy_lints/src/doc/mod.rs
index 15530c3dbc509..3d8ce7becdbda 100644
--- a/src/tools/clippy/clippy_lints/src/doc/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/doc/mod.rs
@@ -22,7 +22,6 @@ use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{AnonConst, Attribute, Expr, ImplItemKind, ItemKind, Node, Safety, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::nested_filter;
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_resolve::rustdoc::{
     DocFragment, add_doc_fragment, attrs_to_doc_fragments, main_body_opts, source_span_for_markdown_range,
@@ -675,7 +674,7 @@ impl<'tcx> LateLintPass<'tcx> for Documentation {
                 match item.kind {
                     ItemKind::Fn { sig, body: body_id, .. } => {
                         if !(is_entrypoint_fn(cx, item.owner_id.to_def_id())
-                            || in_external_macro(cx.tcx.sess, item.span))
+                            || item.span.in_external_macro(cx.tcx.sess.source_map()))
                         {
                             let body = cx.tcx.hir().body(body_id);
 
@@ -711,7 +710,7 @@ impl<'tcx> LateLintPass<'tcx> for Documentation {
             },
             Node::TraitItem(trait_item) => {
                 if let TraitItemKind::Fn(sig, ..) = trait_item.kind
-                    && !in_external_macro(cx.tcx.sess, trait_item.span)
+                    && !trait_item.span.in_external_macro(cx.tcx.sess.source_map())
                 {
                     missing_headers::check(
                         cx,
@@ -726,7 +725,7 @@ impl<'tcx> LateLintPass<'tcx> for Documentation {
             },
             Node::ImplItem(impl_item) => {
                 if let ImplItemKind::Fn(sig, body_id) = impl_item.kind
-                    && !in_external_macro(cx.tcx.sess, impl_item.span)
+                    && !impl_item.span.in_external_macro(cx.tcx.sess.source_map())
                     && !is_trait_impl_item(cx, impl_item.hir_id())
                 {
                     let body = cx.tcx.hir().body(body_id);
@@ -791,7 +790,7 @@ fn check_attrs(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs: &[
 
     let (fragments, _) = attrs_to_doc_fragments(
         attrs.iter().filter_map(|attr| {
-            if in_external_macro(cx.sess(), attr.span) {
+            if attr.span.in_external_macro(cx.sess().source_map()) {
                 None
             } else {
                 Some((attr, None))
diff --git a/src/tools/clippy/clippy_lints/src/else_if_without_else.rs b/src/tools/clippy/clippy_lints/src/else_if_without_else.rs
index 5315f55ba3882..a38e853172f70 100644
--- a/src/tools/clippy/clippy_lints/src/else_if_without_else.rs
+++ b/src/tools/clippy/clippy_lints/src/else_if_without_else.rs
@@ -1,7 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use rustc_ast::ast::{Expr, ExprKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -50,7 +49,7 @@ impl EarlyLintPass for ElseIfWithoutElse {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, item: &Expr) {
         if let ExprKind::If(_, _, Some(ref els)) = item.kind
             && let ExprKind::If(_, _, None) = els.kind
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
         {
             #[expect(clippy::collapsible_span_lint_calls, reason = "rust-clippy#7797")]
             span_lint_and_then(
diff --git a/src/tools/clippy/clippy_lints/src/endian_bytes.rs b/src/tools/clippy/clippy_lints/src/endian_bytes.rs
index 209104c5385c9..29deaaf3bc7af 100644
--- a/src/tools/clippy/clippy_lints/src/endian_bytes.rs
+++ b/src/tools/clippy/clippy_lints/src/endian_bytes.rs
@@ -3,7 +3,6 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::is_lint_allowed;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::Ty;
 use rustc_session::declare_lint_pass;
 use rustc_span::Symbol;
@@ -119,7 +118,7 @@ impl LateLintPass<'_> for EndianBytes {
             },
             _ => return,
         };
-        if !in_external_macro(cx.sess(), expr.span)
+        if !expr.span.in_external_macro(cx.sess().source_map())
             && let ty = cx.typeck_results().expr_ty(ty_expr)
             && ty.is_primitive_ty()
         {
diff --git a/src/tools/clippy/clippy_lints/src/equatable_if_let.rs b/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
index 7ca2c9536998c..cd9ab2764ac48 100644
--- a/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
+++ b/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
@@ -4,7 +4,6 @@ use clippy_utils::ty::implements_trait;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, Pat, PatKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::Ty;
 use rustc_session::declare_lint_pass;
 
@@ -72,7 +71,7 @@ impl<'tcx> LateLintPass<'tcx> for PatternEquality {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         if let ExprKind::Let(let_expr) = expr.kind
             && unary_pattern(let_expr.pat)
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
         {
             let exp_ty = cx.typeck_results().expr_ty(let_expr.init);
             let pat_ty = cx.typeck_results().pat_ty(let_expr.pat);
diff --git a/src/tools/clippy/clippy_lints/src/excessive_nesting.rs b/src/tools/clippy/clippy_lints/src/excessive_nesting.rs
index dfea40db182f2..36567b3ded0b1 100644
--- a/src/tools/clippy/clippy_lints/src/excessive_nesting.rs
+++ b/src/tools/clippy/clippy_lints/src/excessive_nesting.rs
@@ -5,7 +5,6 @@ use rustc_ast::node_id::NodeSet;
 use rustc_ast::visit::{Visitor, walk_block, walk_item};
 use rustc_ast::{Block, Crate, Inline, Item, ItemKind, ModKind, NodeId};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 
@@ -125,7 +124,7 @@ struct NestingVisitor<'conf, 'cx> {
 
 impl NestingVisitor<'_, '_> {
     fn check_indent(&mut self, span: Span, id: NodeId) -> bool {
-        if self.nest_level > self.conf.excessive_nesting_threshold && !in_external_macro(self.cx.sess(), span) {
+        if self.nest_level > self.conf.excessive_nesting_threshold && !span.in_external_macro(self.cx.sess().source_map()) {
             self.conf.nodes.insert(id);
 
             return true;
diff --git a/src/tools/clippy/clippy_lints/src/extra_unused_type_parameters.rs b/src/tools/clippy/clippy_lints/src/extra_unused_type_parameters.rs
index cdbfe7af8f9de..5d93aceb33ffd 100644
--- a/src/tools/clippy/clippy_lints/src/extra_unused_type_parameters.rs
+++ b/src/tools/clippy/clippy_lints/src/extra_unused_type_parameters.rs
@@ -10,7 +10,6 @@ use rustc_hir::{
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::nested_filter;
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use rustc_span::def_id::{DefId, LocalDefId};
@@ -261,7 +260,7 @@ impl<'tcx> LateLintPass<'tcx> for ExtraUnusedTypeParameters {
             && !generics.params.is_empty()
             && !is_empty_body(cx, body_id)
             && (!self.avoid_breaking_exported_api || !cx.effective_visibilities.is_exported(item.owner_id.def_id))
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
             && !is_from_proc_macro(cx, item)
         {
             let mut walker = TypeWalker::new(cx, generics);
@@ -277,7 +276,7 @@ impl<'tcx> LateLintPass<'tcx> for ExtraUnusedTypeParameters {
             && trait_ref_of_method(cx, item.owner_id.def_id).is_none()
             && !is_empty_body(cx, body_id)
             && (!self.avoid_breaking_exported_api || !cx.effective_visibilities.is_exported(item.owner_id.def_id))
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
             && !is_from_proc_macro(cx, item)
         {
             let mut walker = TypeWalker::new(cx, item.generics);
diff --git a/src/tools/clippy/clippy_lints/src/formatting.rs b/src/tools/clippy/clippy_lints/src/formatting.rs
index 34e93bdb9b9b0..c8fe7ac73cb34 100644
--- a/src/tools/clippy/clippy_lints/src/formatting.rs
+++ b/src/tools/clippy/clippy_lints/src/formatting.rs
@@ -3,7 +3,6 @@ use clippy_utils::is_span_if;
 use clippy_utils::source::snippet_opt;
 use rustc_ast::ast::{BinOpKind, Block, Expr, ExprKind, StmtKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::Span;
 
@@ -202,7 +201,7 @@ fn check_else(cx: &EarlyContext<'_>, expr: &Expr) {
     if let ExprKind::If(_, then, Some(else_)) = &expr.kind
         && (is_block(else_) || is_if(else_))
         && !then.span.from_expansion() && !else_.span.from_expansion()
-        && !in_external_macro(cx.sess(), expr.span)
+        && !expr.span.in_external_macro(cx.sess().source_map())
 
         // workaround for rust-lang/rust#43081
         && expr.span.lo().0 != 0 && expr.span.hi().0 != 0
diff --git a/src/tools/clippy/clippy_lints/src/functions/must_use.rs b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
index 90d3db2700fa0..e480805cac2f8 100644
--- a/src/tools/clippy/clippy_lints/src/functions/must_use.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
@@ -5,7 +5,6 @@ use rustc_hir::def_id::DefIdSet;
 use rustc_hir::{self as hir, Attribute, QPath};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::{Span, sym};
 
@@ -107,7 +106,7 @@ fn check_needless_must_use(
     attrs: &[Attribute],
     sig: &FnSig<'_>,
 ) {
-    if in_external_macro(cx.sess(), item_span) {
+    if item_span.in_external_macro(cx.sess().source_map()) {
         return;
     }
     if returns_unit(decl) {
@@ -185,7 +184,7 @@ fn check_must_use_candidate<'tcx>(
 ) {
     if has_mutable_arg(cx, body)
         || mutates_static(cx, body)
-        || in_external_macro(cx.sess(), item_span)
+        || item_span.in_external_macro(cx.sess().source_map())
         || returns_unit(decl)
         || !cx.effective_visibilities.is_exported(item_id.def_id)
         || is_must_use_ty(cx, return_ty(cx, item_id))
diff --git a/src/tools/clippy/clippy_lints/src/functions/result.rs b/src/tools/clippy/clippy_lints/src/functions/result.rs
index 9c396986f62ac..74d365a725560 100644
--- a/src/tools/clippy/clippy_lints/src/functions/result.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/result.rs
@@ -2,7 +2,6 @@ use clippy_utils::msrvs::{self, Msrv};
 use rustc_errors::Diag;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::{Span, sym};
 
@@ -20,7 +19,7 @@ fn result_err_ty<'tcx>(
     id: hir::def_id::LocalDefId,
     item_span: Span,
 ) -> Option<(&'tcx hir::Ty<'tcx>, Ty<'tcx>)> {
-    if !in_external_macro(cx.sess(), item_span)
+    if !item_span.in_external_macro(cx.sess().source_map())
         && let hir::FnRetTy::Return(hir_ty) = decl.output
         && let ty = cx
             .tcx
diff --git a/src/tools/clippy/clippy_lints/src/functions/too_many_lines.rs b/src/tools/clippy/clippy_lints/src/functions/too_many_lines.rs
index 0f5ce340c44dd..4f90d9655b445 100644
--- a/src/tools/clippy/clippy_lints/src/functions/too_many_lines.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/too_many_lines.rs
@@ -3,7 +3,6 @@ use clippy_utils::source::SpanRangeExt;
 use rustc_hir as hir;
 use rustc_hir::intravisit::FnKind;
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_span::Span;
 
 use super::TOO_MANY_LINES;
@@ -17,7 +16,7 @@ pub(super) fn check_fn(
 ) {
     // Closures must be contained in a parent body, which will be checked for `too_many_lines`.
     // Don't check closures for `too_many_lines` to avoid duplicated lints.
-    if matches!(kind, FnKind::Closure) || in_external_macro(cx.sess(), span) {
+    if matches!(kind, FnKind::Closure) || span.in_external_macro(cx.sess().source_map()) {
         return;
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs b/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs
index 3fc0a69652245..51e2944e6f994 100644
--- a/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs
+++ b/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs
@@ -11,7 +11,6 @@ use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 
 declare_clippy_lint! {
@@ -79,7 +78,7 @@ impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
             && is_res_lang_ctor(cx, path_res(cx, peel_blocks(els)), OptionNone)
             && !is_else_clause(cx.tcx, expr)
             && !is_in_const_context(cx)
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && self.msrv.meets(msrvs::BOOL_THEN)
             && !contains_return(then_block.stmts)
         {
diff --git a/src/tools/clippy/clippy_lints/src/implicit_return.rs b/src/tools/clippy/clippy_lints/src/implicit_return.rs
index ba06567b9572c..5f95464e4d494 100644
--- a/src/tools/clippy/clippy_lints/src/implicit_return.rs
+++ b/src/tools/clippy/clippy_lints/src/implicit_return.rs
@@ -7,7 +7,6 @@ use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, FnRetTy, HirId};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{Span, SyntaxContext};
@@ -227,7 +226,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitReturn {
     ) {
         if (!matches!(kind, FnKind::Closure) && matches!(decl.output, FnRetTy::DefaultReturn(_)))
             || !span.eq_ctxt(body.value.span)
-            || in_external_macro(cx.sess(), span)
+            || span.in_external_macro(cx.sess().source_map())
         {
             return;
         }
diff --git a/src/tools/clippy/clippy_lints/src/items_after_statements.rs b/src/tools/clippy/clippy_lints/src/items_after_statements.rs
index 4f066113aea33..f5ad79a00279e 100644
--- a/src/tools/clippy/clippy_lints/src/items_after_statements.rs
+++ b/src/tools/clippy/clippy_lints/src/items_after_statements.rs
@@ -1,7 +1,6 @@
 use clippy_utils::diagnostics::span_lint_hir;
 use rustc_hir::{Block, ItemKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -70,7 +69,7 @@ impl LateLintPass<'_> for ItemsAfterStatements {
                 // Don't use `next` due to the complex filter chain.
                 .for_each(|item| {
                     // Only do the macro check once, but delay it until it's needed.
-                    if !*in_external.get_or_insert_with(|| in_external_macro(cx.sess(), block.span)) {
+                    if !*in_external.get_or_insert_with(|| block.span.in_external_macro(cx.sess().source_map())) {
                         span_lint_hir(
                             cx,
                             ITEMS_AFTER_STATEMENTS,
diff --git a/src/tools/clippy/clippy_lints/src/iter_without_into_iter.rs b/src/tools/clippy/clippy_lints/src/iter_without_into_iter.rs
index 906da81b18377..238f66d667554 100644
--- a/src/tools/clippy/clippy_lints/src/iter_without_into_iter.rs
+++ b/src/tools/clippy/clippy_lints/src/iter_without_into_iter.rs
@@ -6,7 +6,6 @@ use rustc_ast::Mutability;
 use rustc_errors::Applicability;
 use rustc_hir::{FnRetTy, ImplItemKind, ImplicitSelfKind, ItemKind, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::declare_lint_pass;
 use rustc_span::sym;
@@ -131,7 +130,7 @@ impl LateLintPass<'_> for IterWithoutIntoIter {
             && trait_ref
                 .trait_def_id()
                 .is_some_and(|did| cx.tcx.is_diagnostic_item(sym::IntoIterator, did))
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
             && let &ty::Ref(_, ty, mtbl) = cx.tcx.type_of(item.owner_id).instantiate_identity().kind()
             && let expected_method_name = match mtbl {
                 Mutability::Mut => sym::iter_mut,
@@ -193,7 +192,7 @@ impl {self_ty_without_ref} {{
             _ => return,
         };
 
-        if !in_external_macro(cx.sess(), item.span)
+        if !item.span.in_external_macro(cx.sess().source_map())
             && let ImplItemKind::Fn(sig, _) = item.kind
             && let FnRetTy::Return(ret) = sig.decl.output
             && is_nameable_in_impl_trait(ret)
diff --git a/src/tools/clippy/clippy_lints/src/large_enum_variant.rs b/src/tools/clippy/clippy_lints/src/large_enum_variant.rs
index 923089c722322..d9953dbc261b0 100644
--- a/src/tools/clippy/clippy_lints/src/large_enum_variant.rs
+++ b/src/tools/clippy/clippy_lints/src/large_enum_variant.rs
@@ -5,7 +5,6 @@ use clippy_utils::ty::{AdtVariantInfo, approx_ty_size, is_copy};
 use rustc_errors::Applicability;
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
@@ -78,7 +77,7 @@ impl<'tcx> LateLintPass<'tcx> for LargeEnumVariant {
             && let ty = cx.tcx.type_of(item.owner_id).instantiate_identity()
             && let ty::Adt(adt, subst) = ty.kind()
             && adt.variants().len() > 1
-            && !in_external_macro(cx.tcx.sess, item.span)
+            && !item.span.in_external_macro(cx.tcx.sess.source_map())
         {
             let variants_size = AdtVariantInfo::new(cx, *adt, subst);
 
diff --git a/src/tools/clippy/clippy_lints/src/legacy_numeric_constants.rs b/src/tools/clippy/clippy_lints/src/legacy_numeric_constants.rs
index fb46bdcab6e1d..6f2ce04e8f8e9 100644
--- a/src/tools/clippy/clippy_lints/src/legacy_numeric_constants.rs
+++ b/src/tools/clippy/clippy_lints/src/legacy_numeric_constants.rs
@@ -7,7 +7,6 @@ use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::{ExprKind, Item, ItemKind, QPath, UseKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::symbol::kw;
 use rustc_span::{Symbol, sym};
@@ -54,7 +53,7 @@ impl<'tcx> LateLintPass<'tcx> for LegacyNumericConstants {
         // so lint on the `use` statement directly.
         if let ItemKind::Use(path, kind @ (UseKind::Single | UseKind::Glob)) = item.kind
             && self.msrv.meets(msrvs::NUMERIC_ASSOCIATED_CONSTANTS)
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
             && let Some(def_id) = path.res[0].opt_def_id()
         {
             let module = if is_integer_module(cx, def_id) {
@@ -139,7 +138,7 @@ impl<'tcx> LateLintPass<'tcx> for LegacyNumericConstants {
         };
 
         if self.msrv.meets(msrvs::NUMERIC_ASSOCIATED_CONSTANTS)
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && !is_from_proc_macro(cx, expr)
         {
             span_lint_hir_and_then(cx, LEGACY_NUMERIC_CONSTANTS, expr.hir_id, span, msg, |diag| {
diff --git a/src/tools/clippy/clippy_lints/src/let_underscore.rs b/src/tools/clippy/clippy_lints/src/let_underscore.rs
index b522c22a44d70..bdbf5b37c5f0e 100644
--- a/src/tools/clippy/clippy_lints/src/let_underscore.rs
+++ b/src/tools/clippy/clippy_lints/src/let_underscore.rs
@@ -3,7 +3,6 @@ use clippy_utils::ty::{implements_trait, is_must_use_ty, match_type};
 use clippy_utils::{is_from_proc_macro, is_must_use_func_call, paths};
 use rustc_hir::{LetStmt, LocalSource, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{GenericArgKind, IsSuggestable};
 use rustc_session::declare_lint_pass;
 use rustc_span::{BytePos, Span};
@@ -141,7 +140,7 @@ impl<'tcx> LateLintPass<'tcx> for LetUnderscore {
         if matches!(local.source, LocalSource::Normal)
             && let PatKind::Wild = local.pat.kind
             && let Some(init) = local.init
-            && !in_external_macro(cx.tcx.sess, local.span)
+            && !local.span.in_external_macro(cx.tcx.sess.source_map())
         {
             let init_ty = cx.typeck_results().expr_ty(init);
             let contains_sync_guard = init_ty.walk().any(|inner| match inner.unpack() {
diff --git a/src/tools/clippy/clippy_lints/src/let_with_type_underscore.rs b/src/tools/clippy/clippy_lints/src/let_with_type_underscore.rs
index 34ded6c65009d..9c8488ff381b3 100644
--- a/src/tools/clippy/clippy_lints/src/let_with_type_underscore.rs
+++ b/src/tools/clippy/clippy_lints/src/let_with_type_underscore.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::is_from_proc_macro;
 use rustc_hir::{LetStmt, TyKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -30,7 +29,7 @@ impl<'tcx> LateLintPass<'tcx> for UnderscoreTyped {
         if let Some(ty) = local.ty // Ensure that it has a type defined
             && let TyKind::Infer(()) = &ty.kind // that type is '_'
             && local.span.eq_ctxt(ty.span)
-            && !in_external_macro(cx.tcx.sess, local.span)
+            && !local.span.in_external_macro(cx.tcx.sess.source_map())
             && !is_from_proc_macro(cx, ty)
         {
             span_lint_and_help(
diff --git a/src/tools/clippy/clippy_lints/src/lifetimes.rs b/src/tools/clippy/clippy_lints/src/lifetimes.rs
index c9ab0beb5dfa0..860c0584accfe 100644
--- a/src/tools/clippy/clippy_lints/src/lifetimes.rs
+++ b/src/tools/clippy/clippy_lints/src/lifetimes.rs
@@ -21,7 +21,6 @@ use rustc_hir::{
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::map::Map;
 use rustc_middle::hir::nested_filter as middle_nested_filter;
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use rustc_span::def_id::LocalDefId;
@@ -164,7 +163,7 @@ fn check_fn_inner<'tcx>(
     report_extra_lifetimes: bool,
     msrv: &Msrv,
 ) {
-    if in_external_macro(cx.sess(), span) || has_where_lifetimes(cx, generics) {
+    if span.in_external_macro(cx.sess().source_map()) || has_where_lifetimes(cx, generics) {
         return;
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/literal_representation.rs b/src/tools/clippy/clippy_lints/src/literal_representation.rs
index a4cedf3bed354..805de23408bf5 100644
--- a/src/tools/clippy/clippy_lints/src/literal_representation.rs
+++ b/src/tools/clippy/clippy_lints/src/literal_representation.rs
@@ -6,7 +6,6 @@ use rustc_ast::ast::{Expr, ExprKind, LitKind};
 use rustc_ast::token;
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass, Lint, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use std::iter;
@@ -207,7 +206,7 @@ impl_lint_pass!(LiteralDigitGrouping => [
 impl EarlyLintPass for LiteralDigitGrouping {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
         if let ExprKind::Lit(lit) = expr.kind
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
         {
             self.check_lit(cx, lit, expr.span);
         }
@@ -421,7 +420,7 @@ impl_lint_pass!(DecimalLiteralRepresentation => [DECIMAL_LITERAL_REPRESENTATION]
 impl EarlyLintPass for DecimalLiteralRepresentation {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
         if let ExprKind::Lit(lit) = expr.kind
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
         {
             self.check_lit(cx, lit, expr.span);
         }
diff --git a/src/tools/clippy/clippy_lints/src/loops/infinite_loop.rs b/src/tools/clippy/clippy_lints/src/loops/infinite_loop.rs
index 6be30f3c957bb..4d206850c9984 100644
--- a/src/tools/clippy/clippy_lints/src/loops/infinite_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/infinite_loop.rs
@@ -6,7 +6,6 @@ use rustc_ast::Label;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_span::sym;
 
 use super::INFINITE_LOOP;
@@ -30,7 +29,7 @@ pub(super) fn check<'tcx>(
         return;
     }
 
-    if in_external_macro(cx.sess(), expr.span) || is_from_proc_macro(cx, expr) {
+    if expr.span.in_external_macro(cx.sess().source_map()) || is_from_proc_macro(cx, expr) {
         return;
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/manual_float_methods.rs b/src/tools/clippy/clippy_lints/src/manual_float_methods.rs
index a1951b9da44a9..052e6502da926 100644
--- a/src/tools/clippy/clippy_lints/src/manual_float_methods.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_float_methods.rs
@@ -9,7 +9,6 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{BinOpKind, Constness, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, Lint, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::impl_lint_pass;
 
@@ -142,7 +141,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualFloatMethods {
             // 16 possible alignments of constants/operands. For now, let's use `partition`.
             && let mut exprs = [lhs_lhs, lhs_rhs, rhs_lhs, rhs_rhs]
             && exprs.iter_mut().partition_in_place(|i| path_to_local(i).is_some()) == 2
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && (
                 is_not_const(cx.tcx, cx.tcx.hir().enclosing_body_owner(expr.hir_id).into())
                     || self.msrv.meets(msrvs::CONST_FLOAT_CLASSIFY)
diff --git a/src/tools/clippy/clippy_lints/src/manual_let_else.rs b/src/tools/clippy/clippy_lints/src/manual_let_else.rs
index 274785061b3f8..3643b8c4425ec 100644
--- a/src/tools/clippy/clippy_lints/src/manual_let_else.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_let_else.rs
@@ -9,7 +9,6 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, MatchSource, Pat, PatExpr, PatExprKind, PatKind, QPath, Stmt, StmtKind};
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 
 use rustc_span::Span;
 use rustc_span::symbol::{Symbol, sym};
@@ -55,7 +54,7 @@ impl<'tcx> QuestionMark {
             && init.span.eq_ctxt(stmt.span)
             && let Some(if_let_or_match) = IfLetOrMatch::parse(cx, init)
             && self.msrv.meets(msrvs::LET_ELSE)
-            && !in_external_macro(cx.sess(), stmt.span)
+            && !stmt.span.in_external_macro(cx.sess().source_map())
         {
             match if_let_or_match {
                 IfLetOrMatch::IfLet(if_let_expr, let_pat, if_then, if_else, ..) => {
diff --git a/src/tools/clippy/clippy_lints/src/manual_range_patterns.rs b/src/tools/clippy/clippy_lints/src/manual_range_patterns.rs
index 2e5a92915d9ca..bf4f2bff3195d 100644
--- a/src/tools/clippy/clippy_lints/src/manual_range_patterns.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_range_patterns.rs
@@ -5,7 +5,6 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
 use rustc_hir::{PatExpr, PatExprKind, PatKind, RangeEnd};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::{DUMMY_SP, Span};
 
@@ -80,7 +79,7 @@ impl LateLintPass<'_> for ManualRangePatterns {
         // like described https://github.com/rust-lang/rust-clippy/issues/11825)
         if let PatKind::Or(pats) = pat.kind
             && (pats.len() >= 3 || (pats.len() > 1 && pats.iter().any(|p| matches!(p.kind, PatKind::Range(..)))))
-            && !in_external_macro(cx.sess(), pat.span)
+            && !pat.span.in_external_macro(cx.sess().source_map())
         {
             let mut min = Num::dummy(i128::MAX);
             let mut max = Num::dummy(i128::MIN);
diff --git a/src/tools/clippy/clippy_lints/src/manual_rem_euclid.rs b/src/tools/clippy/clippy_lints/src/manual_rem_euclid.rs
index 8aeec89f0bfa7..469b4b7cf89fb 100644
--- a/src/tools/clippy/clippy_lints/src/manual_rem_euclid.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_rem_euclid.rs
@@ -7,7 +7,6 @@ use clippy_utils::{is_in_const_context, path_to_local};
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, Node, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 
 declare_clippy_lint! {
@@ -60,7 +59,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualRemEuclid {
             && rem_rhs.span.ctxt() == ctxt
             && add_lhs.span.ctxt() == ctxt
             && add_rhs.span.ctxt() == ctxt
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && self.msrv.meets(msrvs::REM_EUCLID)
             && (self.msrv.meets(msrvs::REM_EUCLID_CONST) || !is_in_const_context(cx))
             && let Some(const1) = check_for_unsigned_int_constant(cx, rem_rhs)
diff --git a/src/tools/clippy/clippy_lints/src/matches/mod.rs b/src/tools/clippy/clippy_lints/src/matches/mod.rs
index a7fdd483c16cd..9ca914af281b6 100644
--- a/src/tools/clippy/clippy_lints/src/matches/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/mod.rs
@@ -33,7 +33,6 @@ use clippy_utils::{
 };
 use rustc_hir::{Arm, Expr, ExprKind, LetStmt, MatchSource, Pat, PatKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::{SpanData, SyntaxContext};
 
@@ -1054,7 +1053,7 @@ impl_lint_pass!(Matches => [
 impl<'tcx> LateLintPass<'tcx> for Matches {
     #[expect(clippy::too_many_lines)]
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if is_direct_expn_of(expr.span, "matches").is_none() && in_external_macro(cx.sess(), expr.span) {
+        if is_direct_expn_of(expr.span, "matches").is_none() && expr.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
         let from_expansion = expr.span.from_expansion();
diff --git a/src/tools/clippy/clippy_lints/src/mem_replace.rs b/src/tools/clippy/clippy_lints/src/mem_replace.rs
index 5597cd85abc90..41528c5dee3ae 100644
--- a/src/tools/clippy/clippy_lints/src/mem_replace.rs
+++ b/src/tools/clippy/clippy_lints/src/mem_replace.rs
@@ -11,7 +11,6 @@ use rustc_errors::Applicability;
 use rustc_hir::LangItem::OptionNone;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use rustc_span::symbol::sym;
@@ -188,7 +187,7 @@ fn check_replace_with_default(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<
     if is_non_aggregate_primitive_type(expr_type) {
         return;
     }
-    if is_default_equivalent(cx, src) && !in_external_macro(cx.tcx.sess, expr_span) {
+    if is_default_equivalent(cx, src) && !expr_span.in_external_macro(cx.tcx.sess.source_map()) {
         let Some(top_crate) = std_or_core(cx) else { return };
         span_lint_and_then(
             cx,
diff --git a/src/tools/clippy/clippy_lints/src/methods/filter_map_bool_then.rs b/src/tools/clippy/clippy_lints/src/methods/filter_map_bool_then.rs
index 129e692542894..d550c14546686 100644
--- a/src/tools/clippy/clippy_lints/src/methods/filter_map_bool_then.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/filter_map_bool_then.rs
@@ -6,13 +6,12 @@ use clippy_utils::{is_from_proc_macro, is_trait_method, peel_blocks};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::Binder;
 use rustc_middle::ty::adjustment::Adjust;
 use rustc_span::{Span, sym};
 
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, arg: &Expr<'_>, call_span: Span) {
-    if !in_external_macro(cx.sess(), expr.span)
+    if !expr.span.in_external_macro(cx.sess().source_map())
         && is_trait_method(cx, expr, sym::Iterator)
         && let ExprKind::Closure(closure) = arg.kind
         && let body = cx.tcx.hir().body(closure.body)
diff --git a/src/tools/clippy/clippy_lints/src/methods/is_empty.rs b/src/tools/clippy/clippy_lints/src/methods/is_empty.rs
index a0c21faaa4cc8..92c81b3c49d87 100644
--- a/src/tools/clippy/clippy_lints/src/methods/is_empty.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/is_empty.rs
@@ -4,7 +4,6 @@ use clippy_utils::macros::{is_assert_macro, root_macro_call};
 use clippy_utils::{find_binding_init, get_parent_expr, is_inside_always_const_context, path_to_local};
 use rustc_hir::{Expr, HirId};
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_span::sym;
 
 use super::CONST_IS_EMPTY;
@@ -12,7 +11,7 @@ use super::CONST_IS_EMPTY;
 /// Expression whose initialization depend on a constant conditioned by a `#[cfg(…)]` directive will
 /// not trigger the lint.
 pub(super) fn check(cx: &LateContext<'_>, expr: &'_ Expr<'_>, receiver: &Expr<'_>) {
-    if in_external_macro(cx.sess(), expr.span) || !receiver.span.eq_ctxt(expr.span) {
+    if expr.span.in_external_macro(cx.sess().source_map()) || !receiver.span.eq_ctxt(expr.span) {
         return;
     }
     if let Some(parent) = get_parent_expr(cx, expr) {
diff --git a/src/tools/clippy/clippy_lints/src/methods/manual_try_fold.rs b/src/tools/clippy/clippy_lints/src/methods/manual_try_fold.rs
index 4a48d4b547ccc..a56378b5b73ae 100644
--- a/src/tools/clippy/clippy_lints/src/methods/manual_try_fold.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/manual_try_fold.rs
@@ -7,7 +7,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_span::{Span, sym};
 
 use super::MANUAL_TRY_FOLD;
@@ -20,7 +19,7 @@ pub(super) fn check<'tcx>(
     fold_span: Span,
     msrv: &Msrv,
 ) {
-    if !in_external_macro(cx.sess(), fold_span)
+    if !fold_span.in_external_macro(cx.sess().source_map())
         && msrv.meets(msrvs::ITERATOR_TRY_FOLD)
         && is_trait_method(cx, expr, sym::Iterator)
         && let init_ty = cx.typeck_results().expr_ty(init)
diff --git a/src/tools/clippy/clippy_lints/src/methods/mod.rs b/src/tools/clippy/clippy_lints/src/methods/mod.rs
index 42418318fda8d..2f447775fa5b3 100644
--- a/src/tools/clippy/clippy_lints/src/methods/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/mod.rs
@@ -152,7 +152,6 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::{Expr, ExprKind, Node, Stmt, StmtKind, TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, TraitRef, Ty};
 use rustc_session::impl_lint_pass;
 use rustc_span::{Span, sym};
@@ -4625,7 +4624,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
 
     #[allow(clippy::too_many_lines)]
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx hir::ImplItem<'_>) {
-        if in_external_macro(cx.sess(), impl_item.span) {
+        if impl_item.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
         let name = impl_item.ident.name.as_str();
@@ -4713,7 +4712,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
     }
 
     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'_>) {
-        if in_external_macro(cx.tcx.sess, item.span) {
+        if item.span.in_external_macro(cx.tcx.sess.source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/min_ident_chars.rs b/src/tools/clippy/clippy_lints/src/min_ident_chars.rs
index a99e21d938c64..4119b1d1051cb 100644
--- a/src/tools/clippy/clippy_lints/src/min_ident_chars.rs
+++ b/src/tools/clippy/clippy_lints/src/min_ident_chars.rs
@@ -6,7 +6,6 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::{Visitor, walk_item, walk_trait_item};
 use rustc_hir::{GenericParamKind, HirId, Item, ItemKind, ItemLocalId, Node, Pat, PatKind, TraitItem, UsePath};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use std::borrow::Cow;
@@ -55,7 +54,7 @@ impl MinIdentChars {
 
     #[expect(clippy::cast_possible_truncation)]
     fn is_ident_too_short(&self, cx: &LateContext<'_>, str: &str, span: Span) -> bool {
-        !in_external_macro(cx.sess(), span)
+        !span.in_external_macro(cx.sess().source_map())
             && str.len() <= self.min_ident_chars_threshold as usize
             && !str.starts_with('_')
             && !str.is_empty()
diff --git a/src/tools/clippy/clippy_lints/src/misc.rs b/src/tools/clippy/clippy_lints/src/misc.rs
index b511b1e46b386..fa0eb9a94b73a 100644
--- a/src/tools/clippy/clippy_lints/src/misc.rs
+++ b/src/tools/clippy/clippy_lints/src/misc.rs
@@ -13,7 +13,6 @@ use rustc_hir::{
     BinOpKind, BindingMode, Body, ByRef, Expr, ExprKind, FnDecl, Mutability, PatKind, QPath, Stmt, StmtKind,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::Span;
 use rustc_span::def_id::LocalDefId;
@@ -162,7 +161,7 @@ impl<'tcx> LateLintPass<'tcx> for LintPass {
             for arg in iter_input_pats(decl, body) {
                 if let PatKind::Binding(BindingMode(ByRef::Yes(_), _), ..) = arg.pat.kind
                     && is_lint_allowed(cx, REF_PATTERNS, arg.pat.hir_id)
-                    && !in_external_macro(cx.tcx.sess, arg.span)
+                    && !arg.span.in_external_macro(cx.tcx.sess.source_map())
                 {
                     span_lint_hir(
                         cx,
@@ -183,7 +182,7 @@ impl<'tcx> LateLintPass<'tcx> for LintPass {
             && let Some(init) = local.init
             // Do not emit if clippy::ref_patterns is not allowed to avoid having two lints for the same issue.
             && is_lint_allowed(cx, REF_PATTERNS, local.pat.hir_id)
-            && !in_external_macro(cx.tcx.sess, stmt.span)
+            && !stmt.span.in_external_macro(cx.tcx.sess.source_map())
         {
             let ctxt = local.span.ctxt();
             let mut app = Applicability::MachineApplicable;
@@ -239,7 +238,7 @@ impl<'tcx> LateLintPass<'tcx> for LintPass {
     }
 
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if in_external_macro(cx.sess(), expr.span)
+        if expr.span.in_external_macro(cx.sess().source_map())
             || expr.span.desugaring_kind().is_some()
             || in_automatically_derived(cx.tcx, expr.hir_id)
         {
diff --git a/src/tools/clippy/clippy_lints/src/misc_early/mod.rs b/src/tools/clippy/clippy_lints/src/misc_early/mod.rs
index 637d6ed3ad2c6..f880f1f329ff7 100644
--- a/src/tools/clippy/clippy_lints/src/misc_early/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/misc_early/mod.rs
@@ -14,7 +14,6 @@ use rustc_ast::token;
 use rustc_ast::visit::FnKind;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::Span;
 
@@ -350,7 +349,7 @@ impl EarlyLintPass for MiscEarlyLints {
     }
 
     fn check_pat(&mut self, cx: &EarlyContext<'_>, pat: &Pat) {
-        if in_external_macro(cx.sess(), pat.span) {
+        if pat.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
@@ -387,7 +386,7 @@ impl EarlyLintPass for MiscEarlyLints {
     }
 
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
-        if in_external_macro(cx.sess(), expr.span) {
+        if expr.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/misc_early/redundant_at_rest_pattern.rs b/src/tools/clippy/clippy_lints/src/misc_early/redundant_at_rest_pattern.rs
index 0c81ee5eced85..f2cf93465c0d7 100644
--- a/src/tools/clippy/clippy_lints/src/misc_early/redundant_at_rest_pattern.rs
+++ b/src/tools/clippy/clippy_lints/src/misc_early/redundant_at_rest_pattern.rs
@@ -2,12 +2,11 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use rustc_ast::{Pat, PatKind};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, LintContext};
-use rustc_middle::lint::in_external_macro;
 
 use super::REDUNDANT_AT_REST_PATTERN;
 
 pub(super) fn check(cx: &EarlyContext<'_>, pat: &Pat) {
-    if !in_external_macro(cx.sess(), pat.span)
+    if !pat.span.in_external_macro(cx.sess().source_map())
         && let PatKind::Slice(slice) = &pat.kind
         && let [one] = &**slice
         && let PatKind::Ident(annotation, ident, Some(rest)) = &one.kind
diff --git a/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs b/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
index 2572e186ce6cb..962d85c6a9d31 100644
--- a/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
@@ -8,7 +8,6 @@ use rustc_hir::def_id::CRATE_DEF_ID;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{self as hir, Body, Constness, FnDecl, GenericParamKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
@@ -106,7 +105,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingConstForFn {
             return;
         }
 
-        if in_external_macro(cx.tcx.sess, span) || is_entrypoint_fn(cx, def_id.to_def_id()) {
+        if span.in_external_macro(cx.tcx.sess.source_map()) || is_entrypoint_fn(cx, def_id.to_def_id()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/missing_inline.rs b/src/tools/clippy/clippy_lints/src/missing_inline.rs
index bba1b63be277f..18385ac926924 100644
--- a/src/tools/clippy/clippy_lints/src/missing_inline.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_inline.rs
@@ -88,7 +88,7 @@ declare_lint_pass!(MissingInline => [MISSING_INLINE_IN_PUBLIC_ITEMS]);
 
 impl<'tcx> LateLintPass<'tcx> for MissingInline {
     fn check_item(&mut self, cx: &LateContext<'tcx>, it: &'tcx hir::Item<'_>) {
-        if rustc_middle::lint::in_external_macro(cx.sess(), it.span) || is_executable_or_proc_macro(cx) {
+        if it.span.in_external_macro(cx.sess().source_map()) || is_executable_or_proc_macro(cx) {
             return;
         }
 
@@ -139,7 +139,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingInline {
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx hir::ImplItem<'_>) {
-        if rustc_middle::lint::in_external_macro(cx.sess(), impl_item.span) || is_executable_or_proc_macro(cx) {
+        if impl_item.span.in_external_macro(cx.sess().source_map()) || is_executable_or_proc_macro(cx) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs b/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs
index aad6ae52a6db0..302db2c914ca5 100644
--- a/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs
+++ b/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs
@@ -6,7 +6,6 @@ use hir::{BlockCheckMode, ExprKind, QPath, UnOp};
 use rustc_ast::Mutability;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 use rustc_span::{DesugaringKind, Span};
@@ -65,7 +64,7 @@ declare_lint_pass!(MultipleUnsafeOpsPerBlock => [MULTIPLE_UNSAFE_OPS_PER_BLOCK])
 impl<'tcx> LateLintPass<'tcx> for MultipleUnsafeOpsPerBlock {
     fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx hir::Block<'_>) {
         if !matches!(block.rules, BlockCheckMode::UnsafeBlock(_))
-            || in_external_macro(cx.tcx.sess, block.span)
+            || block.span.in_external_macro(cx.tcx.sess.source_map())
             || block.span.is_desugaring(DesugaringKind::Await)
         {
             return;
diff --git a/src/tools/clippy/clippy_lints/src/mut_mut.rs b/src/tools/clippy/clippy_lints/src/mut_mut.rs
index 0ee851a4cf948..3c4ba5141dd9b 100644
--- a/src/tools/clippy/clippy_lints/src/mut_mut.rs
+++ b/src/tools/clippy/clippy_lints/src/mut_mut.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::{span_lint, span_lint_hir};
 use clippy_utils::higher;
 use rustc_hir::{self as hir, AmbigArg, intravisit};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 
@@ -38,7 +37,7 @@ impl<'tcx> LateLintPass<'tcx> for MutMut {
             && mty.mutbl == hir::Mutability::Mut
             && let hir::TyKind::Ref(_, mty) = mty.ty.kind
             && mty.mutbl == hir::Mutability::Mut
-            && !in_external_macro(cx.sess(), ty.span)
+            && !ty.span.in_external_macro(cx.sess().source_map())
         {
             span_lint(
                 cx,
@@ -56,7 +55,7 @@ pub struct MutVisitor<'a, 'tcx> {
 
 impl<'tcx> intravisit::Visitor<'tcx> for MutVisitor<'_, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
-        if in_external_macro(self.cx.sess(), expr.span) {
+        if expr.span.in_external_macro(self.cx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/needless_if.rs b/src/tools/clippy/clippy_lints/src/needless_if.rs
index 8e14fbf2f8061..7eefb016aca98 100644
--- a/src/tools/clippy/clippy_lints/src/needless_if.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_if.rs
@@ -5,7 +5,6 @@ use clippy_utils::source::SpanRangeExt;
 use rustc_errors::Applicability;
 use rustc_hir::{ExprKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -47,7 +46,7 @@ impl LateLintPass<'_> for NeedlessIf {
             && let ExprKind::Block(block, ..) = then.kind
             && block.stmts.is_empty()
             && block.expr.is_none()
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && then.span.check_source_text(cx, |src| {
                 // Ignore
                 // - empty macro expansions
diff --git a/src/tools/clippy/clippy_lints/src/neg_cmp_op_on_partial_ord.rs b/src/tools/clippy/clippy_lints/src/neg_cmp_op_on_partial_ord.rs
index fa90ee606121b..4f62ba2e58db2 100644
--- a/src/tools/clippy/clippy_lints/src/neg_cmp_op_on_partial_ord.rs
+++ b/src/tools/clippy/clippy_lints/src/neg_cmp_op_on_partial_ord.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::span_lint;
 use clippy_utils::ty::implements_trait;
 use rustc_hir::{BinOpKind, Expr, ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::sym;
 
@@ -48,7 +47,7 @@ impl<'tcx> LateLintPass<'tcx> for NoNegCompOpForPartialOrd {
         if let ExprKind::Unary(UnOp::Not, inner) = expr.kind
             && let ExprKind::Binary(ref op, left, _) = inner.kind
             && let BinOpKind::Le | BinOpKind::Ge | BinOpKind::Lt | BinOpKind::Gt = op.node
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
         {
             let ty = cx.typeck_results().expr_ty(left);
 
diff --git a/src/tools/clippy/clippy_lints/src/new_without_default.rs b/src/tools/clippy/clippy_lints/src/new_without_default.rs
index 688374b5676ce..cc56df3a23d7f 100644
--- a/src/tools/clippy/clippy_lints/src/new_without_default.rs
+++ b/src/tools/clippy/clippy_lints/src/new_without_default.rs
@@ -6,7 +6,6 @@ use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::HirIdSet;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::sym;
 
@@ -69,7 +68,7 @@ impl<'tcx> LateLintPass<'tcx> for NewWithoutDefault {
             for assoc_item in *items {
                 if assoc_item.kind == (hir::AssocItemKind::Fn { has_self: false }) {
                     let impl_item = cx.tcx.hir().impl_item(assoc_item.id);
-                    if in_external_macro(cx.sess(), impl_item.span) {
+                    if impl_item.span.in_external_macro(cx.sess().source_map()) {
                         return;
                     }
                     if let hir::ImplItemKind::Fn(ref sig, _) = impl_item.kind {
diff --git a/src/tools/clippy/clippy_lints/src/no_effect.rs b/src/tools/clippy/clippy_lints/src/no_effect.rs
index ccd5075804455..4d3e6aa79d0a0 100644
--- a/src/tools/clippy/clippy_lints/src/no_effect.rs
+++ b/src/tools/clippy/clippy_lints/src/no_effect.rs
@@ -12,7 +12,6 @@ use rustc_hir::{
 };
 use rustc_infer::infer::TyCtxtInferExt as _;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
@@ -268,7 +267,7 @@ fn has_no_effect(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
 
 fn check_unnecessary_operation(cx: &LateContext<'_>, stmt: &Stmt<'_>) {
     if let StmtKind::Semi(expr) = stmt.kind
-        && !in_external_macro(cx.sess(), stmt.span)
+        && !stmt.span.in_external_macro(cx.sess().source_map())
         && let ctxt = stmt.span.ctxt()
         && expr.span.ctxt() == ctxt
         && let Some(reduced) = reduce_expression(cx, expr)
diff --git a/src/tools/clippy/clippy_lints/src/non_canonical_impls.rs b/src/tools/clippy/clippy_lints/src/non_canonical_impls.rs
index 94855c4656778..dad1e8a3d6a14 100644
--- a/src/tools/clippy/clippy_lints/src/non_canonical_impls.rs
+++ b/src/tools/clippy/clippy_lints/src/non_canonical_impls.rs
@@ -5,7 +5,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::{Expr, ExprKind, ImplItem, ImplItemKind, LangItem, Node, UnOp};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::EarlyBinder;
 use rustc_session::declare_lint_pass;
 use rustc_span::sym;
@@ -129,7 +128,7 @@ impl LateLintPass<'_> for NonCanonicalImpls {
         let ExprKind::Block(block, ..) = body.value.kind else {
             return;
         };
-        if in_external_macro(cx.sess(), block.span) || is_from_proc_macro(cx, impl_item) {
+        if block.span.in_external_macro(cx.sess().source_map()) || is_from_proc_macro(cx, impl_item) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs b/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
index 56c4157d6fe05..1a3b43cbb10a5 100644
--- a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
+++ b/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
@@ -5,7 +5,6 @@ use rustc_ast::ast::{
 };
 use rustc_ast::visit::{Visitor, walk_block, walk_expr, walk_pat};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::{Span, sym};
@@ -381,7 +380,7 @@ impl<'tcx> Visitor<'tcx> for SimilarNamesLocalVisitor<'_, 'tcx> {
 
 impl EarlyLintPass for NonExpressiveNames {
     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
-        if in_external_macro(cx.sess(), item.span) {
+        if item.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
@@ -396,7 +395,7 @@ impl EarlyLintPass for NonExpressiveNames {
     }
 
     fn check_impl_item(&mut self, cx: &EarlyContext<'_>, item: &AssocItem) {
-        if in_external_macro(cx.sess(), item.span) {
+        if item.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/non_send_fields_in_send_ty.rs b/src/tools/clippy/clippy_lints/src/non_send_fields_in_send_ty.rs
index 793eb5d945603..9542fed38759a 100644
--- a/src/tools/clippy/clippy_lints/src/non_send_fields_in_send_ty.rs
+++ b/src/tools/clippy/clippy_lints/src/non_send_fields_in_send_ty.rs
@@ -7,7 +7,6 @@ use rustc_ast::ImplPolarity;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{FieldDef, Item, ItemKind, Node};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, GenericArgKind, Ty};
 use rustc_session::impl_lint_pass;
 use rustc_span::sym;
@@ -81,7 +80,7 @@ impl<'tcx> LateLintPass<'tcx> for NonSendFieldInSendTy {
         // We start from `Send` impl instead of `check_field_def()` because
         // single `AdtDef` may have multiple `Send` impls due to generic
         // parameters, and the lint is much easier to implement in this way.
-        if !in_external_macro(cx.tcx.sess, item.span)
+        if !item.span.in_external_macro(cx.tcx.sess.source_map())
             && let Some(send_trait) = cx.tcx.get_diagnostic_item(sym::Send)
             && let ItemKind::Impl(hir_impl) = &item.kind
             && let Some(trait_ref) = &hir_impl.of_trait
diff --git a/src/tools/clippy/clippy_lints/src/non_std_lazy_statics.rs b/src/tools/clippy/clippy_lints/src/non_std_lazy_statics.rs
index 312610db0423c..22116505a1c13 100644
--- a/src/tools/clippy/clippy_lints/src/non_std_lazy_statics.rs
+++ b/src/tools/clippy/clippy_lints/src/non_std_lazy_statics.rs
@@ -9,7 +9,6 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_hir::{self as hir, BodyId, Expr, ExprKind, Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 
@@ -139,7 +138,7 @@ impl<'hir> LateLintPass<'hir> for NonStdLazyStatic {
             return;
         }
 
-        if in_external_macro(cx.sess(), item.span) {
+        if item.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/octal_escapes.rs b/src/tools/clippy/clippy_lints/src/octal_escapes.rs
index 2eae9b23746df..6e7ee727965db 100644
--- a/src/tools/clippy/clippy_lints/src/octal_escapes.rs
+++ b/src/tools/clippy/clippy_lints/src/octal_escapes.rs
@@ -4,7 +4,6 @@ use rustc_ast::token::LitKind;
 use rustc_ast::{Expr, ExprKind};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::{BytePos, Pos, SpanData};
 
@@ -59,7 +58,7 @@ impl EarlyLintPass for OctalEscapes {
                 LitKind::ByteStr | LitKind::CStr => 2,
                 _ => return,
             })
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
         {
             let s = lit.symbol.as_str();
             let mut iter = s.as_bytes().iter();
diff --git a/src/tools/clippy/clippy_lints/src/panicking_overflow_checks.rs b/src/tools/clippy/clippy_lints/src/panicking_overflow_checks.rs
index 7f100a746d5ed..bc1821a48a340 100644
--- a/src/tools/clippy/clippy_lints/src/panicking_overflow_checks.rs
+++ b/src/tools/clippy/clippy_lints/src/panicking_overflow_checks.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::span_lint;
 use clippy_utils::eq_expr_value;
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 
@@ -72,7 +71,7 @@ impl<'tcx> LateLintPass<'tcx> for PanickingOverflowChecks {
             && matches!(ty.kind(), ty::Uint(_))
             && ty == typeck.expr_ty(op_rhs)
             && ty == typeck.expr_ty(other)
-            && !in_external_macro(cx.tcx.sess, expr.span)
+            && !expr.span.in_external_macro(cx.tcx.sess.source_map())
             && (eq_expr_value(cx, op_lhs, other) || (commutative && eq_expr_value(cx, op_rhs, other)))
         {
             span_lint(
diff --git a/src/tools/clippy/clippy_lints/src/pathbuf_init_then_push.rs b/src/tools/clippy/clippy_lints/src/pathbuf_init_then_push.rs
index 668f09bbfd58e..b653b459b04c8 100644
--- a/src/tools/clippy/clippy_lints/src/pathbuf_init_then_push.rs
+++ b/src/tools/clippy/clippy_lints/src/pathbuf_init_then_push.rs
@@ -7,7 +7,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{BindingMode, Block, Expr, ExprKind, HirId, LetStmt, PatKind, QPath, Stmt, StmtKind, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::{Span, Symbol, sym};
 
@@ -136,7 +135,7 @@ impl<'tcx> LateLintPass<'tcx> for PathbufThenPush<'tcx> {
     fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx LetStmt<'tcx>) {
         if let Some(init_expr) = local.init
             && let PatKind::Binding(BindingMode::MUT, id, name, None) = local.pat.kind
-            && !in_external_macro(cx.sess(), local.span)
+            && !local.span.in_external_macro(cx.sess().source_map())
             && let ty = cx.typeck_results().pat_ty(local.pat)
             && is_type_diagnostic_item(cx, ty, sym::PathBuf)
         {
@@ -157,7 +156,7 @@ impl<'tcx> LateLintPass<'tcx> for PathbufThenPush<'tcx> {
             && let ExprKind::Path(QPath::Resolved(None, path)) = left.kind
             && let [name] = &path.segments
             && let Res::Local(id) = path.res
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && let ty = cx.typeck_results().expr_ty(left)
             && is_type_diagnostic_item(cx, ty, sym::PathBuf)
         {
diff --git a/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs b/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs
index 42fbba8ef6dcd..8f1a1ee76c6a6 100644
--- a/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs
+++ b/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs
@@ -3,7 +3,6 @@ use rustc_hir::{
     Body, Expr, ExprKind, FnDecl, LetExpr, LocalSource, Mutability, Pat, PatKind, Stmt, StmtKind, intravisit,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 use rustc_span::Span;
@@ -84,7 +83,7 @@ declare_lint_pass!(PatternTypeMismatch => [PATTERN_TYPE_MISMATCH]);
 impl<'tcx> LateLintPass<'tcx> for PatternTypeMismatch {
     fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
         if let StmtKind::Let(local) = stmt.kind {
-            if in_external_macro(cx.sess(), local.pat.span) {
+            if local.pat.span.in_external_macro(cx.sess().source_map()) {
                 return;
             }
             let deref_possible = match local.source {
@@ -171,7 +170,7 @@ fn find_first_mismatch(cx: &LateContext<'_>, pat: &Pat<'_>) -> Option<(Span, Mut
         if result.is_some() {
             return false;
         }
-        if in_external_macro(cx.sess(), p.span) {
+        if p.span.in_external_macro(cx.sess().source_map()) {
             return true;
         }
         let adjust_pat = match p.kind {
diff --git a/src/tools/clippy/clippy_lints/src/raw_strings.rs b/src/tools/clippy/clippy_lints/src/raw_strings.rs
index 23d0e768c2f17..c6e6e782f9d45 100644
--- a/src/tools/clippy/clippy_lints/src/raw_strings.rs
+++ b/src/tools/clippy/clippy_lints/src/raw_strings.rs
@@ -5,7 +5,6 @@ use rustc_ast::ast::{Expr, ExprKind};
 use rustc_ast::token::LitKind;
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::{BytePos, Pos, Span};
 use std::iter::once;
@@ -72,7 +71,7 @@ impl RawStrings {
 impl EarlyLintPass for RawStrings {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
         if let ExprKind::FormatArgs(format_args) = &expr.kind
-            && !in_external_macro(cx.sess(), format_args.span)
+            && !format_args.span.in_external_macro(cx.sess().source_map())
             && format_args.span.check_source_text(cx, |src| src.starts_with('r'))
             && let Some(str) = snippet_opt(cx.sess(), format_args.span)
             && let count_hash = str.bytes().skip(1).take_while(|b| *b == b'#').count()
@@ -95,7 +94,7 @@ impl EarlyLintPass for RawStrings {
                 LitKind::CStrRaw(max) => ("cr", max),
                 _ => return,
             }
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && expr.span.check_source_text(cx, |src| src.starts_with(prefix))
         {
             self.check_raw_string(cx, lit.symbol.as_str(), expr.span, prefix, max, lit.kind.descr());
diff --git a/src/tools/clippy/clippy_lints/src/redundant_async_block.rs b/src/tools/clippy/clippy_lints/src/redundant_async_block.rs
index 3ade6bcee84d8..65fd312b3a09b 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_async_block.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_async_block.rs
@@ -10,7 +10,6 @@ use rustc_hir::{
     Closure, ClosureKind, CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, ExprKind, MatchSource,
 };
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::UpvarCapture;
 use rustc_session::declare_lint_pass;
 
@@ -47,7 +46,7 @@ declare_lint_pass!(RedundantAsyncBlock => [REDUNDANT_ASYNC_BLOCK]);
 impl<'tcx> LateLintPass<'tcx> for RedundantAsyncBlock {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         let span = expr.span;
-        if !in_external_macro(cx.tcx.sess, span) &&
+        if !span.in_external_macro(cx.tcx.sess.source_map()) &&
             let Some(body_expr) = desugar_async_block(cx, expr) &&
             let Some(expr) = desugar_await(peel_blocks(body_expr)) &&
             // The await prefix must not come from a macro as its content could change in the future.
diff --git a/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs b/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
index b4dadef57a3c5..91d023500ca67 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
@@ -10,7 +10,6 @@ use rustc_hir::{
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::nested_filter;
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 use rustc_span::ExpnKind;
@@ -138,7 +137,7 @@ fn get_parent_call_exprs<'tcx>(
 
 impl<'tcx> LateLintPass<'tcx> for RedundantClosureCall {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
-        if in_external_macro(cx.sess(), expr.span) {
+        if expr.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/redundant_else.rs b/src/tools/clippy/clippy_lints/src/redundant_else.rs
index a27f9b6311430..3476f56cf338f 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_else.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_else.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::span_lint_and_help;
 use rustc_ast::ast::{Block, Expr, ExprKind, Stmt, StmtKind};
 use rustc_ast::visit::{Visitor, walk_expr};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -46,7 +45,7 @@ declare_lint_pass!(RedundantElse => [REDUNDANT_ELSE]);
 
 impl EarlyLintPass for RedundantElse {
     fn check_stmt(&mut self, cx: &EarlyContext<'_>, stmt: &Stmt) {
-        if in_external_macro(cx.sess(), stmt.span) {
+        if stmt.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
         // Only look at expressions that are a whole statement
diff --git a/src/tools/clippy/clippy_lints/src/redundant_field_names.rs b/src/tools/clippy/clippy_lints/src/redundant_field_names.rs
index 347540e7344f9..707abc008a862 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_field_names.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_field_names.rs
@@ -4,7 +4,6 @@ use clippy_utils::msrvs::{self, Msrv};
 use rustc_ast::ast::{Expr, ExprKind};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 
 declare_clippy_lint! {
@@ -56,7 +55,7 @@ impl EarlyLintPass for RedundantFieldNames {
             return;
         }
 
-        if in_external_macro(cx.sess(), expr.span) {
+        if expr.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
         if let ExprKind::Struct(ref se) = expr.kind {
diff --git a/src/tools/clippy/clippy_lints/src/redundant_locals.rs b/src/tools/clippy/clippy_lints/src/redundant_locals.rs
index 658d93e634cf9..ebe3e7c201964 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_locals.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_locals.rs
@@ -6,7 +6,6 @@ use rustc_hir::def::Res;
 use rustc_hir::{BindingMode, ByRef, ExprKind, HirId, LetStmt, Node, Pat, PatKind, QPath};
 use rustc_hir_typeck::expr_use_visitor::PlaceBase;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::UpvarCapture;
 use rustc_session::declare_lint_pass;
 use rustc_span::DesugaringKind;
@@ -69,7 +68,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantLocals {
             // the local does not affect the code's drop behavior
             && !needs_ordered_drop(cx, cx.typeck_results().expr_ty(expr))
             // the local is user-controlled
-            && !in_external_macro(cx.sess(), local.span)
+            && !local.span.in_external_macro(cx.sess().source_map())
             && !is_from_proc_macro(cx, expr)
             && !is_by_value_closure_capture(cx, local.hir_id, binding_id)
         {
diff --git a/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs b/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
index 8d6b1c7274d93..6a17b83b3d01b 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
@@ -4,7 +4,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::impl_lint_pass;
 use rustc_span::def_id::CRATE_DEF_ID;
@@ -51,7 +50,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantPubCrate {
             && !cx.effective_visibilities.is_exported(item.owner_id.def_id)
             && self.is_exported.last() == Some(&false)
             && is_not_macro_export(item)
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
         {
             let span = item.span.with_hi(item.ident.span.hi());
             let descr = cx.tcx.def_kind(item.owner_id).descr(item.owner_id.to_def_id());
diff --git a/src/tools/clippy/clippy_lints/src/reserve_after_initialization.rs b/src/tools/clippy/clippy_lints/src/reserve_after_initialization.rs
index 6157adad059cd..152d7450f5ff5 100644
--- a/src/tools/clippy/clippy_lints/src/reserve_after_initialization.rs
+++ b/src/tools/clippy/clippy_lints/src/reserve_after_initialization.rs
@@ -6,7 +6,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{BindingMode, Block, Expr, ExprKind, HirId, LetStmt, PatKind, QPath, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 
@@ -72,7 +71,7 @@ impl<'tcx> LateLintPass<'tcx> for ReserveAfterInitialization {
     fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx LetStmt<'tcx>) {
         if let Some(init_expr) = local.init
             && let PatKind::Binding(BindingMode::MUT, id, _, None) = local.pat.kind
-            && !in_external_macro(cx.sess(), local.span)
+            && !local.span.in_external_macro(cx.sess().source_map())
             && let Some(init) = get_vec_init_kind(cx, init_expr)
             && !matches!(
                 init,
@@ -101,7 +100,7 @@ impl<'tcx> LateLintPass<'tcx> for ReserveAfterInitialization {
             && let ExprKind::Assign(left, right, _) = expr.kind
             && let ExprKind::Path(QPath::Resolved(None, path)) = left.kind
             && let Res::Local(id) = path.res
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && let Some(init) = get_vec_init_kind(cx, right)
             && !matches!(
                 init,
diff --git a/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs b/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs
index 42d9cf2c88c16..5a25483c397c6 100644
--- a/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs
+++ b/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs
@@ -5,7 +5,6 @@ use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Body, FnDecl, OwnerId, TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::{Span, sym};
 
@@ -69,7 +68,7 @@ declare_clippy_lint! {
 declare_lint_pass!(ReturnSelfNotMustUse => [RETURN_SELF_NOT_MUST_USE]);
 
 fn check_method(cx: &LateContext<'_>, decl: &FnDecl<'_>, fn_def: LocalDefId, span: Span, owner_id: OwnerId) {
-    if !in_external_macro(cx.sess(), span)
+    if !span.in_external_macro(cx.sess().source_map())
         // If it comes from an external macro, better ignore it.
         && decl.implicit_self.has_implicit_self()
         // We only show this warning for public exported methods.
diff --git a/src/tools/clippy/clippy_lints/src/returns.rs b/src/tools/clippy/clippy_lints/src/returns.rs
index 664e984fece3d..a1cf16e6ce9f4 100644
--- a/src/tools/clippy/clippy_lints/src/returns.rs
+++ b/src/tools/clippy/clippy_lints/src/returns.rs
@@ -17,7 +17,6 @@ use rustc_hir::{
     StmtKind,
 };
 use rustc_lint::{LateContext, LateLintPass, Level, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::adjustment::Adjust;
 use rustc_middle::ty::{self, GenericArgKind, Ty};
 use rustc_session::declare_lint_pass;
@@ -191,7 +190,7 @@ fn stmt_needs_never_type(cx: &LateContext<'_>, stmt_hir_id: HirId) -> bool {
 
 impl<'tcx> LateLintPass<'tcx> for Return {
     fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
-        if !in_external_macro(cx.sess(), stmt.span)
+        if !stmt.span.in_external_macro(cx.sess().source_map())
             && let StmtKind::Semi(expr) = stmt.kind
             && let ExprKind::Ret(Some(ret)) = expr.kind
             // return Err(...)? desugars to a match
@@ -237,8 +236,8 @@ impl<'tcx> LateLintPass<'tcx> for Return {
             && let PatKind::Binding(_, local_id, _, _) = local.pat.kind
             && path_to_local_id(retexpr, local_id)
             && !last_statement_borrows(cx, initexpr)
-            && !in_external_macro(cx.sess(), initexpr.span)
-            && !in_external_macro(cx.sess(), retexpr.span)
+            && !initexpr.span.in_external_macro(cx.sess().source_map())
+            && !retexpr.span.in_external_macro(cx.sess().source_map())
             && !local.span.from_expansion()
             && !span_contains_cfg(cx, stmt.span.between(retexpr.span))
         {
diff --git a/src/tools/clippy/clippy_lints/src/single_call_fn.rs b/src/tools/clippy/clippy_lints/src/single_call_fn.rs
index 0176077c70e04..fdbccbaa8a594 100644
--- a/src/tools/clippy/clippy_lints/src/single_call_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/single_call_fn.rs
@@ -6,7 +6,6 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::{Expr, ExprKind, HirId, Node};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 
@@ -88,7 +87,7 @@ impl SingleCallFn {
         fn_span: Span,
     ) -> bool {
         (self.avoid_breaking_exported_api && cx.effective_visibilities.is_exported(fn_def_id))
-            || in_external_macro(cx.sess(), fn_span)
+            || fn_span.in_external_macro(cx.sess().source_map())
             || cx
                 .tcx
                 .hir()
diff --git a/src/tools/clippy/clippy_lints/src/single_char_lifetime_names.rs b/src/tools/clippy/clippy_lints/src/single_char_lifetime_names.rs
index d92b890950a3f..50a6ee316c8a6 100644
--- a/src/tools/clippy/clippy_lints/src/single_char_lifetime_names.rs
+++ b/src/tools/clippy/clippy_lints/src/single_char_lifetime_names.rs
@@ -1,7 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use rustc_ast::ast::{GenericParam, GenericParamKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -42,7 +41,7 @@ declare_lint_pass!(SingleCharLifetimeNames => [SINGLE_CHAR_LIFETIME_NAMES]);
 
 impl EarlyLintPass for SingleCharLifetimeNames {
     fn check_generic_param(&mut self, ctx: &EarlyContext<'_>, param: &GenericParam) {
-        if in_external_macro(ctx.sess(), param.ident.span) {
+        if param.ident.span.in_external_macro(ctx.sess().source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs b/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs
index 8ec7bfe9edd3f..59c13a1e2c533 100644
--- a/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs
+++ b/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs
@@ -8,7 +8,6 @@ use rustc_hir::def::Res;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{HirId, Path, PathSegment};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::symbol::kw;
 use rustc_span::{Span, sym};
@@ -112,7 +111,7 @@ impl<'tcx> LateLintPass<'tcx> for StdReexports {
         if let Res::Def(_, def_id) = path.res
             && let Some(first_segment) = get_first_segment(path)
             && is_stable(cx, def_id, &self.msrv)
-            && !in_external_macro(cx.sess(), path.span)
+            && !path.span.in_external_macro(cx.sess().source_map())
             && !is_from_proc_macro(cx, &first_segment.ident)
         {
             let (lint, used_mod, replace_with) = match first_segment.ident.name {
diff --git a/src/tools/clippy/clippy_lints/src/strings.rs b/src/tools/clippy/clippy_lints/src/strings.rs
index 2925f355d0b6d..6164a6191db04 100644
--- a/src/tools/clippy/clippy_lints/src/strings.rs
+++ b/src/tools/clippy/clippy_lints/src/strings.rs
@@ -9,7 +9,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, LangItem, Node, QPath};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 use rustc_span::source_map::Spanned;
@@ -147,7 +146,7 @@ declare_lint_pass!(StringAdd => [STRING_ADD, STRING_ADD_ASSIGN, STRING_SLICE]);
 
 impl<'tcx> LateLintPass<'tcx> for StringAdd {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
-        if in_external_macro(cx.sess(), e.span) {
+        if e.span.in_external_macro(cx.sess().source_map()) {
             return;
         }
         match e.kind {
@@ -284,7 +283,7 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
             );
         }
 
-        if !in_external_macro(cx.sess(), e.span)
+        if !e.span.in_external_macro(cx.sess().source_map())
             && let ExprKind::MethodCall(path, receiver, ..) = &e.kind
             && path.ident.name.as_str() == "as_bytes"
             && let ExprKind::Lit(lit) = &receiver.kind
diff --git a/src/tools/clippy/clippy_lints/src/suspicious_xor_used_as_pow.rs b/src/tools/clippy/clippy_lints/src/suspicious_xor_used_as_pow.rs
index d1d822a553260..e55d17818e4fb 100644
--- a/src/tools/clippy/clippy_lints/src/suspicious_xor_used_as_pow.rs
+++ b/src/tools/clippy/clippy_lints/src/suspicious_xor_used_as_pow.rs
@@ -5,7 +5,6 @@ use rustc_ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -32,7 +31,7 @@ declare_lint_pass!(ConfusingXorAndPow => [SUSPICIOUS_XOR_USED_AS_POW]);
 
 impl LateLintPass<'_> for ConfusingXorAndPow {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        if !in_external_macro(cx.sess(), expr.span)
+        if !expr.span.in_external_macro(cx.sess().source_map())
             && let ExprKind::Binary(op, left, right) = &expr.kind
             && op.node == BinOpKind::BitXor
             && left.span.eq_ctxt(right.span)
diff --git a/src/tools/clippy/clippy_lints/src/swap.rs b/src/tools/clippy/clippy_lints/src/swap.rs
index 9b4c3d275ae73..7176d533b6164 100644
--- a/src/tools/clippy/clippy_lints/src/swap.rs
+++ b/src/tools/clippy/clippy_lints/src/swap.rs
@@ -12,7 +12,6 @@ use rustc_hir::intravisit::{Visitor, walk_expr};
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Block, Expr, ExprKind, LetStmt, PatKind, QPath, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 use rustc_span::source_map::Spanned;
@@ -212,7 +211,7 @@ fn check_suspicious_swap(cx: &LateContext<'_>, block: &Block<'_>) {
         if let Some((lhs0, rhs0)) = parse(first)
             && let Some((lhs1, rhs1)) = parse(second)
             && first.span.eq_ctxt(second.span)
-			&& !in_external_macro(cx.sess(), first.span)
+			&& !first.span.in_external_macro(cx.sess().source_map())
             && is_same(cx, lhs0, rhs1)
             && is_same(cx, lhs1, rhs0)
 			&& !is_same(cx, lhs1, rhs1) // Ignore a = b; a = a (#10421)
diff --git a/src/tools/clippy/clippy_lints/src/transmute/missing_transmute_annotations.rs b/src/tools/clippy/clippy_lints/src/transmute/missing_transmute_annotations.rs
index bed4e60ba62da..4961dd6b280a1 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/missing_transmute_annotations.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/missing_transmute_annotations.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use rustc_errors::Applicability;
 use rustc_hir::{GenericArg, HirId, LetStmt, Node, Path, TyKind};
 use rustc_lint::LateContext;
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::Ty;
 
 use crate::transmute::MISSING_TRANSMUTE_ANNOTATIONS;
@@ -44,7 +43,7 @@ pub(super) fn check<'tcx>(
     expr_hir_id: HirId,
 ) -> bool {
     let last = path.segments.last().unwrap();
-    if in_external_macro(cx.tcx.sess, last.ident.span) {
+    if last.ident.span.in_external_macro(cx.tcx.sess.source_map()) {
         // If it comes from a non-local macro, we ignore it.
         return false;
     }
diff --git a/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs b/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs
index 008e09dd8bd12..c7aefc65f707f 100644
--- a/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs
+++ b/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs
@@ -7,7 +7,6 @@ use itertools::Itertools;
 use rustc_ast::LitKind;
 use rustc_hir::{Expr, ExprKind, Node, PatKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::impl_lint_pass;
 use std::iter::once;
@@ -56,7 +55,7 @@ impl TupleArrayConversions {
 
 impl LateLintPass<'_> for TupleArrayConversions {
     fn check_expr<'tcx>(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-        if in_external_macro(cx.sess(), expr.span) || !self.msrv.meets(msrvs::TUPLE_ARRAY_CONVERSIONS) {
+        if expr.span.in_external_macro(cx.sess().source_map()) || !self.msrv.meets(msrvs::TUPLE_ARRAY_CONVERSIONS) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/undocumented_unsafe_blocks.rs b/src/tools/clippy/clippy_lints/src/undocumented_unsafe_blocks.rs
index 45d730985bb1d..5e5d6a9e333b6 100644
--- a/src/tools/clippy/clippy_lints/src/undocumented_unsafe_blocks.rs
+++ b/src/tools/clippy/clippy_lints/src/undocumented_unsafe_blocks.rs
@@ -11,7 +11,6 @@ use rustc_hir as hir;
 use rustc_hir::{Block, BlockCheckMode, ItemKind, Node, UnsafeSource};
 use rustc_lexer::{TokenKind, tokenize};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::{BytePos, Pos, RelativeBytePos, Span, SyntaxContext};
 
@@ -111,7 +110,7 @@ impl_lint_pass!(UndocumentedUnsafeBlocks => [UNDOCUMENTED_UNSAFE_BLOCKS, UNNECES
 impl<'tcx> LateLintPass<'tcx> for UndocumentedUnsafeBlocks {
     fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx Block<'tcx>) {
         if block.rules == BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided)
-            && !in_external_macro(cx.tcx.sess, block.span)
+            && !block.span.in_external_macro(cx.tcx.sess.source_map())
             && !is_lint_allowed(cx, UNDOCUMENTED_UNSAFE_BLOCKS, block.hir_id)
             && !is_unsafe_from_proc_macro(cx, block.span)
             && !block_has_safety_comment(cx, block.span)
@@ -143,7 +142,7 @@ impl<'tcx> LateLintPass<'tcx> for UndocumentedUnsafeBlocks {
 
         if let Some(tail) = block.expr
             && !is_lint_allowed(cx, UNNECESSARY_SAFETY_COMMENT, tail.hir_id)
-            && !in_external_macro(cx.tcx.sess, tail.span)
+            && !tail.span.in_external_macro(cx.tcx.sess.source_map())
             && let HasSafetyComment::Yes(pos) = stmt_has_safety_comment(cx, tail.span, tail.hir_id)
             && let Some(help_span) = expr_has_unnecessary_safety_comment(cx, tail, pos)
         {
@@ -167,7 +166,7 @@ impl<'tcx> LateLintPass<'tcx> for UndocumentedUnsafeBlocks {
             return;
         };
         if !is_lint_allowed(cx, UNNECESSARY_SAFETY_COMMENT, stmt.hir_id)
-            && !in_external_macro(cx.tcx.sess, stmt.span)
+            && !stmt.span.in_external_macro(cx.tcx.sess.source_map())
             && let HasSafetyComment::Yes(pos) = stmt_has_safety_comment(cx, stmt.span, stmt.hir_id)
             && let Some(help_span) = expr_has_unnecessary_safety_comment(cx, expr, pos)
         {
@@ -184,7 +183,7 @@ impl<'tcx> LateLintPass<'tcx> for UndocumentedUnsafeBlocks {
     }
 
     fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) {
-        if in_external_macro(cx.tcx.sess, item.span) {
+        if item.span.in_external_macro(cx.tcx.sess.source_map()) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/uninhabited_references.rs b/src/tools/clippy/clippy_lints/src/uninhabited_references.rs
index ee9ef01725389..b342f37f0c5ff 100644
--- a/src/tools/clippy/clippy_lints/src/uninhabited_references.rs
+++ b/src/tools/clippy/clippy_lints/src/uninhabited_references.rs
@@ -3,7 +3,6 @@ use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Body, Expr, ExprKind, FnDecl, FnRetTy, TyKind, UnOp};
 use rustc_hir_analysis::lower_ty;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::Span;
 use rustc_span::def_id::LocalDefId;
@@ -40,7 +39,7 @@ declare_lint_pass!(UninhabitedReferences => [UNINHABITED_REFERENCES]);
 
 impl LateLintPass<'_> for UninhabitedReferences {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &'_ Expr<'_>) {
-        if in_external_macro(cx.tcx.sess, expr.span) {
+        if expr.span.in_external_macro(cx.tcx.sess.source_map()) {
             return;
         }
 
@@ -66,7 +65,7 @@ impl LateLintPass<'_> for UninhabitedReferences {
         span: Span,
         _: LocalDefId,
     ) {
-        if in_external_macro(cx.tcx.sess, span) || matches!(kind, FnKind::Closure) {
+        if span.in_external_macro(cx.tcx.sess.source_map()) || matches!(kind, FnKind::Closure) {
             return;
         }
         if let FnRetTy::Return(hir_ty) = fndecl.output
diff --git a/src/tools/clippy/clippy_lints/src/uninit_vec.rs b/src/tools/clippy/clippy_lints/src/uninit_vec.rs
index 93ed15777e015..7803d5115c971 100644
--- a/src/tools/clippy/clippy_lints/src/uninit_vec.rs
+++ b/src/tools/clippy/clippy_lints/src/uninit_vec.rs
@@ -4,7 +4,6 @@ use clippy_utils::ty::{is_type_diagnostic_item, is_uninit_value_valid_for_ty};
 use clippy_utils::{SpanlessEq, is_integer_literal, is_lint_allowed, path_to_local_id, peel_hir_expr_while};
 use rustc_hir::{Block, Expr, ExprKind, HirId, PatKind, PathSegment, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 use rustc_span::{Span, sym};
@@ -64,7 +63,7 @@ declare_lint_pass!(UninitVec => [UNINIT_VEC]);
 // Threads: https://github.com/rust-lang/rust-clippy/pull/7682#discussion_r710998368
 impl<'tcx> LateLintPass<'tcx> for UninitVec {
     fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx Block<'_>) {
-        if !in_external_macro(cx.tcx.sess, block.span) {
+        if !block.span.in_external_macro(cx.tcx.sess.source_map()) {
             for w in block.stmts.windows(2) {
                 if let StmtKind::Expr(expr) | StmtKind::Semi(expr) = w[1].kind {
                     handle_uninit_vec_pair(cx, &w[0], expr);
diff --git a/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs b/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs
index 660bdb9e2be24..00b80e827d8ac 100644
--- a/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs
+++ b/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs
@@ -7,7 +7,6 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::{Visitor, walk_body};
 use rustc_hir::{Expr, ExprKind, HirId, HirIdSet, LetStmt, MatchSource, Node, PatKind, QPath, TyKind};
 use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::{in_external_macro, is_from_async_await};
 use rustc_middle::ty;
 
 use super::LET_UNIT_VALUE;
@@ -22,8 +21,8 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, local: &'tcx LetStmt<'_>) {
 
     if let Some(init) = local.init
         && !local.pat.span.from_expansion()
-        && !in_external_macro(cx.sess(), local.span)
-        && !is_from_async_await(local.span)
+        && !local.span.in_external_macro(cx.sess().source_map())
+        && !local.span.is_from_async_await()
         && cx.typeck_results().pat_ty(local.pat).is_unit()
     {
         // skip `let awa = ()`
diff --git a/src/tools/clippy/clippy_lints/src/unused_result_ok.rs b/src/tools/clippy/clippy_lints/src/unused_result_ok.rs
index 0c0d10eac5b8c..958f19d183357 100644
--- a/src/tools/clippy/clippy_lints/src/unused_result_ok.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_result_ok.rs
@@ -4,7 +4,6 @@ use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_errors::Applicability;
 use rustc_hir::{ExprKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::sym;
 
@@ -39,7 +38,7 @@ impl LateLintPass<'_> for UnusedResultOk {
             && let ExprKind::MethodCall(ok_path, recv, [], ..) = expr.kind //check is expr.ok() has type Result<T,E>.ok(, _)
             && ok_path.ident.as_str() == "ok"
             && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv), sym::Result)
-            && !in_external_macro(cx.sess(), stmt.span)
+            && !stmt.span.in_external_macro(cx.sess().source_map())
         {
             let ctxt = expr.span.ctxt();
             let mut applicability = Applicability::MaybeIncorrect;
diff --git a/src/tools/clippy/clippy_lints/src/unused_trait_names.rs b/src/tools/clippy/clippy_lints/src/unused_trait_names.rs
index 17ee5fc20ca2c..f83415834351f 100644
--- a/src/tools/clippy/clippy_lints/src/unused_trait_names.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_trait_names.rs
@@ -7,7 +7,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Item, ItemKind, UseKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext as _};
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::Visibility;
 use rustc_session::impl_lint_pass;
 use rustc_span::symbol::kw;
@@ -63,7 +62,7 @@ impl_lint_pass!(UnusedTraitNames => [UNUSED_TRAIT_NAMES]);
 impl<'tcx> LateLintPass<'tcx> for UnusedTraitNames {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
         if self.msrv.meets(msrvs::UNDERSCORE_IMPORTS)
-            && !in_external_macro(cx.sess(), item.span)
+            && !item.span.in_external_macro(cx.sess().source_map())
             && let ItemKind::Use(path, UseKind::Single) = item.kind
             // Ignore imports that already use Underscore
             && item.ident.name != kw::Underscore
diff --git a/src/tools/clippy/clippy_lints/src/unwrap.rs b/src/tools/clippy/clippy_lints/src/unwrap.rs
index eaa119b045f1c..6a952c0d97aac 100644
--- a/src/tools/clippy/clippy_lints/src/unwrap.rs
+++ b/src/tools/clippy/clippy_lints/src/unwrap.rs
@@ -8,7 +8,6 @@ use rustc_hir::{BinOpKind, Body, Expr, ExprKind, FnDecl, HirId, Node, PathSegmen
 use rustc_hir_typeck::expr_use_visitor::{Delegate, ExprUseVisitor, PlaceWithHirId};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter;
-use rustc_middle::lint::in_external_macro;
 use rustc_middle::mir::FakeReadCause;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_session::declare_lint_pass;
@@ -292,7 +291,7 @@ impl<'tcx> Visitor<'tcx> for UnwrappableVariablesVisitor<'_, 'tcx> {
 
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
         // Shouldn't lint when `expr` is in macro.
-        if in_external_macro(self.cx.tcx.sess, expr.span) {
+        if expr.span.in_external_macro(self.cx.tcx.sess.source_map()) {
             return;
         }
         if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr) {
diff --git a/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs b/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs
index c3843279ba2e8..3449468ef4804 100644
--- a/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs
+++ b/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs
@@ -4,7 +4,6 @@ use core::mem::replace;
 use rustc_errors::Applicability;
 use rustc_hir::{HirId, Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::symbol::Ident;
 
@@ -126,7 +125,7 @@ fn check_ident(cx: &LateContext<'_>, ident: &Ident, hir_id: HirId, be_aggressive
 impl LateLintPass<'_> for UpperCaseAcronyms {
     fn check_item(&mut self, cx: &LateContext<'_>, it: &Item<'_>) {
         // do not lint public items or in macros
-        if in_external_macro(cx.sess(), it.span)
+        if it.span.in_external_macro(cx.sess().source_map())
             || (self.avoid_breaking_exported_api && cx.effective_visibilities.is_exported(it.owner_id.def_id))
         {
             return;
diff --git a/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs b/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs
index d87d554eb0749..3c23662e9d168 100644
--- a/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs
+++ b/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs
@@ -8,7 +8,6 @@ use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{BindingMode, Block, Expr, ExprKind, HirId, LetStmt, Mutability, PatKind, QPath, Stmt, StmtKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
 use rustc_span::{Span, Symbol};
 
@@ -158,7 +157,7 @@ impl<'tcx> LateLintPass<'tcx> for VecInitThenPush {
     fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx LetStmt<'tcx>) {
         if let Some(init_expr) = local.init
             && let PatKind::Binding(BindingMode::MUT, id, name, None) = local.pat.kind
-            && !in_external_macro(cx.sess(), local.span)
+            && !local.span.in_external_macro(cx.sess().source_map())
             && let Some(init) = get_vec_init_kind(cx, init_expr)
             && !matches!(init, VecInitKind::WithExprCapacity(_))
         {
@@ -181,7 +180,7 @@ impl<'tcx> LateLintPass<'tcx> for VecInitThenPush {
             && let ExprKind::Path(QPath::Resolved(None, path)) = left.kind
             && let [name] = &path.segments
             && let Res::Local(id) = path.res
-            && !in_external_macro(cx.sess(), expr.span)
+            && !expr.span.in_external_macro(cx.sess().source_map())
             && let Some(init) = get_vec_init_kind(cx, right)
             && !matches!(init, VecInitKind::WithExprCapacity(_))
         {
diff --git a/src/tools/clippy/clippy_lints/src/visibility.rs b/src/tools/clippy/clippy_lints/src/visibility.rs
index 2e5fc5834e24f..d17b3df992166 100644
--- a/src/tools/clippy/clippy_lints/src/visibility.rs
+++ b/src/tools/clippy/clippy_lints/src/visibility.rs
@@ -3,7 +3,6 @@ use clippy_utils::source::SpanRangeExt;
 use rustc_ast::ast::{Item, VisibilityKind};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
 use rustc_span::Span;
 use rustc_span::symbol::kw;
@@ -79,7 +78,7 @@ declare_lint_pass!(Visibility => [NEEDLESS_PUB_SELF, PUB_WITH_SHORTHAND, PUB_WIT
 
 impl EarlyLintPass for Visibility {
     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
-        if !in_external_macro(cx.sess(), item.span)
+        if !item.span.in_external_macro(cx.sess().source_map())
             && let VisibilityKind::Restricted { path, shorthand, .. } = &item.vis.kind
         {
             if **path == kw::SelfLower && !is_from_proc_macro(cx, item.vis.span) {
diff --git a/tests/rustdoc/inline_local/fully-stable-path-is-better.rs b/tests/rustdoc/inline_local/fully-stable-path-is-better.rs
index 88b0b0d57b084..41bf42d2e7aad 100644
--- a/tests/rustdoc/inline_local/fully-stable-path-is-better.rs
+++ b/tests/rustdoc/inline_local/fully-stable-path-is-better.rs
@@ -16,10 +16,10 @@ pub mod stb1 {
 #[unstable(feature = "uns", issue = "135003")]
 pub mod uns {
     #[stable(since = "1.0", feature = "stb1")]
-    #[rustc_allowed_through_unstable_modules]
+    #[rustc_allowed_through_unstable_modules = "use stable path instead"]
     pub struct Inside1;
     #[stable(since = "1.0", feature = "stb2")]
-    #[rustc_allowed_through_unstable_modules]
+    #[rustc_allowed_through_unstable_modules = "use stable path instead"]
     pub struct Inside2;
 }
 
diff --git a/tests/rustdoc/stability.rs b/tests/rustdoc/stability.rs
index b74abb0e0ba4c..22cd4b9cd5952 100644
--- a/tests/rustdoc/stability.rs
+++ b/tests/rustdoc/stability.rs
@@ -85,7 +85,7 @@ pub mod stable_later {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_allowed_through_unstable_modules]
+#[rustc_allowed_through_unstable_modules = "use stable path instead"]
 pub mod stable_earlier1 {
     //@ has stability/stable_earlier1/struct.StableInUnstable.html \
     //      '//div[@class="main-heading"]//span[@class="since"]' '1.0.0'
diff --git a/tests/ui/borrowck/already-borrowed-as-mutable-if-let-133941.rs b/tests/ui/borrowck/already-borrowed-as-mutable-if-let-133941.rs
new file mode 100644
index 0000000000000..934aac8383db1
--- /dev/null
+++ b/tests/ui/borrowck/already-borrowed-as-mutable-if-let-133941.rs
@@ -0,0 +1,46 @@
+// https://github.com/rust-lang/rust/issues/133941
+use std::marker::PhantomData;
+
+struct Bar<'a>(PhantomData<&'a mut i32>);
+
+impl<'a> Drop for Bar<'a> {
+    fn drop(&mut self) {}
+}
+
+struct Foo();
+
+impl Foo {
+    fn f(&mut self) -> Option<Bar<'_>> {
+        None
+    }
+
+    fn g(&mut self) {}
+}
+
+fn main() {
+    let mut foo = Foo();
+    while let Some(_) = foo.f() {
+        //~^ HELP matches!
+        foo.g();
+        //~^ ERROR [E0499]
+    }
+    if let Some(_) = foo.f() {
+        //~^ HELP matches!
+        foo.g();
+        //~^ ERROR [E0499]
+    }
+    while let Some(_x) = foo.f() {
+        foo.g();
+        //~^ ERROR [E0499]
+    }
+    if let Some(_x) = foo.f() {
+        foo.g();
+        //~^ ERROR [E0499]
+    }
+    while let Some(_x) = {let _x = foo.f(); foo.g(); None::<()>} {
+        //~^ ERROR [E0499]
+    }
+    if let Some(_x) = {let _x = foo.f(); foo.g(); None::<()>} {
+        //~^ ERROR [E0499]
+    }
+}
diff --git a/tests/ui/borrowck/already-borrowed-as-mutable-if-let-133941.stderr b/tests/ui/borrowck/already-borrowed-as-mutable-if-let-133941.stderr
new file mode 100644
index 0000000000000..bb21caccbaf91
--- /dev/null
+++ b/tests/ui/borrowck/already-borrowed-as-mutable-if-let-133941.stderr
@@ -0,0 +1,89 @@
+error[E0499]: cannot borrow `foo` as mutable more than once at a time
+  --> $DIR/already-borrowed-as-mutable-if-let-133941.rs:24:9
+   |
+LL |     while let Some(_) = foo.f() {
+   |                         -------
+   |                         |
+   |                         first mutable borrow occurs here
+   |                         a temporary with access to the first borrow is created here ...
+LL |
+LL |         foo.g();
+   |         ^^^ second mutable borrow occurs here
+LL |
+LL |     }
+   |     - ... and the first borrow might be used here, when that temporary is dropped and runs the destructor for type `Option<Bar<'_>>`
+   |
+help: consider using the `matches!` macro
+   |
+LL |     while matches!(foo.f(), Some(_)) {
+   |           ~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0499]: cannot borrow `foo` as mutable more than once at a time
+  --> $DIR/already-borrowed-as-mutable-if-let-133941.rs:29:9
+   |
+LL |     if let Some(_) = foo.f() {
+   |                      -------
+   |                      |
+   |                      first mutable borrow occurs here
+   |                      a temporary with access to the first borrow is created here ...
+LL |
+LL |         foo.g();
+   |         ^^^ second mutable borrow occurs here
+LL |
+LL |     }
+   |     - ... and the first borrow might be used here, when that temporary is dropped and runs the destructor for type `Option<Bar<'_>>`
+   |
+help: consider using the `matches!` macro
+   |
+LL |     if matches!(foo.f(), Some(_)) {
+   |        ~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0499]: cannot borrow `foo` as mutable more than once at a time
+  --> $DIR/already-borrowed-as-mutable-if-let-133941.rs:33:9
+   |
+LL |     while let Some(_x) = foo.f() {
+   |                          -------
+   |                          |
+   |                          first mutable borrow occurs here
+   |                          a temporary with access to the first borrow is created here ...
+LL |         foo.g();
+   |         ^^^ second mutable borrow occurs here
+LL |
+LL |     }
+   |     - ... and the first borrow might be used here, when that temporary is dropped and runs the destructor for type `Option<Bar<'_>>`
+
+error[E0499]: cannot borrow `foo` as mutable more than once at a time
+  --> $DIR/already-borrowed-as-mutable-if-let-133941.rs:37:9
+   |
+LL |     if let Some(_x) = foo.f() {
+   |                       -------
+   |                       |
+   |                       first mutable borrow occurs here
+   |                       a temporary with access to the first borrow is created here ...
+LL |         foo.g();
+   |         ^^^ second mutable borrow occurs here
+LL |
+LL |     }
+   |     - ... and the first borrow might be used here, when that temporary is dropped and runs the destructor for type `Option<Bar<'_>>`
+
+error[E0499]: cannot borrow `foo` as mutable more than once at a time
+  --> $DIR/already-borrowed-as-mutable-if-let-133941.rs:40:45
+   |
+LL |     while let Some(_x) = {let _x = foo.f(); foo.g(); None::<()>} {
+   |                                    ---      ^^^                - first borrow might be used here, when `_x` is dropped and runs the destructor for type `Option<Bar<'_>>`
+   |                                    |        |
+   |                                    |        second mutable borrow occurs here
+   |                                    first mutable borrow occurs here
+
+error[E0499]: cannot borrow `foo` as mutable more than once at a time
+  --> $DIR/already-borrowed-as-mutable-if-let-133941.rs:43:42
+   |
+LL |     if let Some(_x) = {let _x = foo.f(); foo.g(); None::<()>} {
+   |                                 ---      ^^^                - first borrow might be used here, when `_x` is dropped and runs the destructor for type `Option<Bar<'_>>`
+   |                                 |        |
+   |                                 |        second mutable borrow occurs here
+   |                                 first mutable borrow occurs here
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0499`.
diff --git a/tests/ui/derives/rustc-decodable-issue-123156.rs b/tests/ui/derives/rustc-decodable-issue-123156.rs
deleted file mode 100644
index 1983837ed8d46..0000000000000
--- a/tests/ui/derives/rustc-decodable-issue-123156.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-//@ check-pass
-//@ edition:2021
-//@ aux-build:rustc-serialize.rs
-
-#![crate_type = "lib"]
-#![allow(deprecated, soft_unstable)]
-
-extern crate rustc_serialize;
-
-#[derive(RustcDecodable)]
-pub enum Foo {}
diff --git a/tests/ui/derives/rustc-decodable-issue-123156.stderr b/tests/ui/derives/rustc-decodable-issue-123156.stderr
deleted file mode 100644
index 93a993b90d814..0000000000000
--- a/tests/ui/derives/rustc-decodable-issue-123156.stderr
+++ /dev/null
@@ -1,10 +0,0 @@
-Future incompatibility report: Future breakage diagnostic:
-warning: use of unstable library feature `rustc_encodable_decodable`: derive macro for `rustc-serialize`; should not be used in new code
-  --> $DIR/rustc-decodable-issue-123156.rs:10:10
-   |
-LL | #[derive(RustcDecodable)]
-   |          ^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
-
diff --git a/tests/ui/error-codes/E0789.rs b/tests/ui/error-codes/E0789.rs
index 3acc983edc4ec..08471e1b3f3e9 100644
--- a/tests/ui/error-codes/E0789.rs
+++ b/tests/ui/error-codes/E0789.rs
@@ -4,7 +4,7 @@
 #![feature(staged_api)]
 #![unstable(feature = "foo_module", reason = "...", issue = "123")]
 
-#[rustc_allowed_through_unstable_modules]
+#[rustc_allowed_through_unstable_modules = "use stable path instead"]
 // #[stable(feature = "foo", since = "1.0")]
 struct Foo;
 //~^ ERROR `rustc_allowed_through_unstable_modules` attribute must be paired with a `stable` attribute
diff --git a/tests/ui/error-emitter/E0308-clarification.rs b/tests/ui/error-emitter/E0308-clarification.rs
new file mode 100644
index 0000000000000..4c15ede00415e
--- /dev/null
+++ b/tests/ui/error-emitter/E0308-clarification.rs
@@ -0,0 +1,16 @@
+//@ compile-flags: -Zunstable-options --error-format=human-unicode --color=always
+//@ only-linux
+// Ensure that when we have a type error where both types have the same textual representation, the
+// diagnostic machinery highlights the clarifying comment that comes after in parentheses.
+trait Foo: Copy + ToString {}
+
+impl<T: Copy + ToString> Foo for T {}
+
+fn hide<T: Foo>(x: T) -> impl Foo {
+    x
+}
+
+fn main() {
+    let mut x = (hide(0_u32), hide(0_i32));
+    x = (x.1, x.0);
+}
diff --git a/tests/ui/error-emitter/E0308-clarification.svg b/tests/ui/error-emitter/E0308-clarification.svg
new file mode 100644
index 0000000000000..9432e3a4ee918
--- /dev/null
+++ b/tests/ui/error-emitter/E0308-clarification.svg
@@ -0,0 +1,97 @@
+<svg width="740px" height="668px" xmlns="http://www.w3.org/2000/svg">
+  <style>
+    .fg { fill: #AAAAAA }
+    .bg { background: #000000 }
+    .fg-ansi256-009 { fill: #FF5555 }
+    .fg-ansi256-012 { fill: #5555FF }
+    .fg-magenta { fill: #AA00AA }
+    .container {
+      padding: 0 10px;
+      line-height: 18px;
+    }
+    .bold { font-weight: bold; }
+    tspan {
+      font: 14px SFMono-Regular, Consolas, Liberation Mono, Menlo, monospace;
+      white-space: pre;
+      line-height: 18px;
+    }
+  </style>
+
+  <rect width="100%" height="100%" y="0" rx="4.5" class="bg" />
+
+  <text xml:space="preserve" class="container fg">
+    <tspan x="10px" y="28px"><tspan class="fg-ansi256-009 bold">error[E0308]</tspan><tspan class="bold">: mismatched types</tspan>
+</tspan>
+    <tspan x="10px" y="46px"><tspan>  </tspan><tspan class="fg-ansi256-012 bold"> ╭▸ </tspan><tspan>$DIR/E0308-clarification.rs:15:10</tspan>
+</tspan>
+    <tspan x="10px" y="64px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan>
+</tspan>
+    <tspan x="10px" y="82px"><tspan class="fg-ansi256-012 bold">LL</tspan><tspan> </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan> fn hide&lt;T: Foo&gt;(x: T) -&gt; impl Foo {</tspan>
+</tspan>
+    <tspan x="10px" y="100px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">┬───────</tspan>
+</tspan>
+    <tspan x="10px" y="118px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">│</tspan>
+</tspan>
+    <tspan x="10px" y="136px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">the expected opaque type</tspan>
+</tspan>
+    <tspan x="10px" y="154px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">the found opaque type</tspan>
+</tspan>
+    <tspan x="10px" y="172px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">‡</tspan>
+</tspan>
+    <tspan x="10px" y="190px"><tspan class="fg-ansi256-012 bold">LL</tspan><tspan> </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>     x = (x.1, x.0);</tspan>
+</tspan>
+    <tspan x="10px" y="208px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>          </tspan><tspan class="fg-ansi256-009 bold">━━━</tspan><tspan> </tspan><tspan class="fg-ansi256-009 bold">expected `u32`, found `i32`</tspan>
+</tspan>
+    <tspan x="10px" y="226px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan>
+</tspan>
+    <tspan x="10px" y="244px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">├ </tspan><tspan class="bold">note</tspan><tspan>: expected opaque type `</tspan><tspan class="fg-magenta bold">impl Foo</tspan><tspan>` (</tspan><tspan class="fg-magenta bold">`u32`</tspan><tspan>)</tspan>
+</tspan>
+    <tspan x="10px" y="262px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>          found opaque type `</tspan><tspan class="fg-magenta bold">impl Foo</tspan><tspan>` (</tspan><tspan class="fg-magenta bold">`i32`</tspan><tspan>)</tspan>
+</tspan>
+    <tspan x="10px" y="280px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">╰ </tspan><tspan class="bold">note</tspan><tspan>: distinct uses of `impl Trait` result in different opaque types</tspan>
+</tspan>
+    <tspan x="10px" y="298px">
+</tspan>
+    <tspan x="10px" y="316px"><tspan class="fg-ansi256-009 bold">error[E0308]</tspan><tspan class="bold">: mismatched types</tspan>
+</tspan>
+    <tspan x="10px" y="334px"><tspan>  </tspan><tspan class="fg-ansi256-012 bold"> ╭▸ </tspan><tspan>$DIR/E0308-clarification.rs:15:15</tspan>
+</tspan>
+    <tspan x="10px" y="352px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan>
+</tspan>
+    <tspan x="10px" y="370px"><tspan class="fg-ansi256-012 bold">LL</tspan><tspan> </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan> fn hide&lt;T: Foo&gt;(x: T) -&gt; impl Foo {</tspan>
+</tspan>
+    <tspan x="10px" y="388px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">┬───────</tspan>
+</tspan>
+    <tspan x="10px" y="406px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">│</tspan>
+</tspan>
+    <tspan x="10px" y="424px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">the expected opaque type</tspan>
+</tspan>
+    <tspan x="10px" y="442px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>                          </tspan><tspan class="fg-ansi256-012 bold">the found opaque type</tspan>
+</tspan>
+    <tspan x="10px" y="460px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">‡</tspan>
+</tspan>
+    <tspan x="10px" y="478px"><tspan class="fg-ansi256-012 bold">LL</tspan><tspan> </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>     x = (x.1, x.0);</tspan>
+</tspan>
+    <tspan x="10px" y="496px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>               </tspan><tspan class="fg-ansi256-009 bold">━━━</tspan><tspan> </tspan><tspan class="fg-ansi256-009 bold">expected `i32`, found `u32`</tspan>
+</tspan>
+    <tspan x="10px" y="514px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan>
+</tspan>
+    <tspan x="10px" y="532px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">├ </tspan><tspan class="bold">note</tspan><tspan>: expected opaque type `</tspan><tspan class="fg-magenta bold">impl Foo</tspan><tspan>` (</tspan><tspan class="fg-magenta bold">`i32`</tspan><tspan>)</tspan>
+</tspan>
+    <tspan x="10px" y="550px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">│</tspan><tspan>          found opaque type `</tspan><tspan class="fg-magenta bold">impl Foo</tspan><tspan>` (</tspan><tspan class="fg-magenta bold">`u32`</tspan><tspan>)</tspan>
+</tspan>
+    <tspan x="10px" y="568px"><tspan>   </tspan><tspan class="fg-ansi256-012 bold">╰ </tspan><tspan class="bold">note</tspan><tspan>: distinct uses of `impl Trait` result in different opaque types</tspan>
+</tspan>
+    <tspan x="10px" y="586px">
+</tspan>
+    <tspan x="10px" y="604px"><tspan class="fg-ansi256-009 bold">error</tspan><tspan class="bold">: aborting due to 2 previous errors</tspan>
+</tspan>
+    <tspan x="10px" y="622px">
+</tspan>
+    <tspan x="10px" y="640px"><tspan class="bold">For more information about this error, try `rustc --explain E0308`.</tspan>
+</tspan>
+    <tspan x="10px" y="658px">
+</tspan>
+  </text>
+
+</svg>
diff --git a/tests/ui/feature-gates/feature-gate-rustc_encodable_decodable.rs b/tests/ui/feature-gates/feature-gate-rustc_encodable_decodable.rs
deleted file mode 100644
index 71caf43806d09..0000000000000
--- a/tests/ui/feature-gates/feature-gate-rustc_encodable_decodable.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-#![crate_type = "lib"]
-
-// This isn't intended to compile, so it's easiest to just ignore this error.
-extern crate rustc_serialize; //~ERROR can't find crate for `rustc_serialize`
-
-#[derive(
-    RustcEncodable,
-    //~^   ERROR   use of unstable library feature `rustc_encodable_decodable`
-    //~^^  WARNING this was previously accepted by the compiler
-    //~^^^ WARNING use of deprecated macro `RustcEncodable`
-    RustcDecodable,
-    //~^   ERROR   use of unstable library feature `rustc_encodable_decodable`
-    //~^^  WARNING this was previously accepted by the compiler
-    //~^^^ WARNING use of deprecated macro `RustcDecodable`
-)]
-struct S;
diff --git a/tests/ui/feature-gates/feature-gate-rustc_encodable_decodable.stderr b/tests/ui/feature-gates/feature-gate-rustc_encodable_decodable.stderr
deleted file mode 100644
index b949dbb9da21c..0000000000000
--- a/tests/ui/feature-gates/feature-gate-rustc_encodable_decodable.stderr
+++ /dev/null
@@ -1,66 +0,0 @@
-error[E0463]: can't find crate for `rustc_serialize`
-  --> $DIR/feature-gate-rustc_encodable_decodable.rs:4:1
-   |
-LL | extern crate rustc_serialize;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't find crate
-   |
-   = help: maybe you need to install the missing components with: `rustup component add rust-src rustc-dev llvm-tools-preview`
-
-error: use of unstable library feature `rustc_encodable_decodable`: derive macro for `rustc-serialize`; should not be used in new code
-  --> $DIR/feature-gate-rustc_encodable_decodable.rs:7:5
-   |
-LL |     RustcEncodable,
-   |     ^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
-   = note: `#[deny(soft_unstable)]` on by default
-
-warning: use of deprecated macro `RustcEncodable`: rustc-serialize is deprecated and no longer supported
-  --> $DIR/feature-gate-rustc_encodable_decodable.rs:7:5
-   |
-LL |     RustcEncodable,
-   |     ^^^^^^^^^^^^^^
-   |
-   = note: `#[warn(deprecated)]` on by default
-
-error: use of unstable library feature `rustc_encodable_decodable`: derive macro for `rustc-serialize`; should not be used in new code
-  --> $DIR/feature-gate-rustc_encodable_decodable.rs:11:5
-   |
-LL |     RustcDecodable,
-   |     ^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
-
-warning: use of deprecated macro `RustcDecodable`: rustc-serialize is deprecated and no longer supported
-  --> $DIR/feature-gate-rustc_encodable_decodable.rs:11:5
-   |
-LL |     RustcDecodable,
-   |     ^^^^^^^^^^^^^^
-
-error: aborting due to 3 previous errors; 2 warnings emitted
-
-For more information about this error, try `rustc --explain E0463`.
-Future incompatibility report: Future breakage diagnostic:
-error: use of unstable library feature `rustc_encodable_decodable`: derive macro for `rustc-serialize`; should not be used in new code
-  --> $DIR/feature-gate-rustc_encodable_decodable.rs:7:5
-   |
-LL |     RustcEncodable,
-   |     ^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
-   = note: `#[deny(soft_unstable)]` on by default
-
-Future breakage diagnostic:
-error: use of unstable library feature `rustc_encodable_decodable`: derive macro for `rustc-serialize`; should not be used in new code
-  --> $DIR/feature-gate-rustc_encodable_decodable.rs:11:5
-   |
-LL |     RustcDecodable,
-   |     ^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
-   = note: `#[deny(soft_unstable)]` on by default
-
diff --git a/tests/ui/impl-trait/impl-trait-in-macro.stderr b/tests/ui/impl-trait/impl-trait-in-macro.stderr
index 4380f47c5de46..2f934694f83f3 100644
--- a/tests/ui/impl-trait/impl-trait-in-macro.stderr
+++ b/tests/ui/impl-trait/impl-trait-in-macro.stderr
@@ -12,8 +12,8 @@ LL |     let mut a = x;
 LL |     a = y;
    |         ^ expected type parameter `impl Debug`, found a different type parameter `impl Debug`
    |
-   = note: expected type parameter `impl Debug` (type parameter `impl Debug`)
-              found type parameter `impl Debug` (type parameter `impl Debug`)
+   = note: expected type parameter `impl Debug`
+              found type parameter `impl Debug`
    = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
    = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
 
diff --git a/tests/ui/impl-trait/universal-two-impl-traits.stderr b/tests/ui/impl-trait/universal-two-impl-traits.stderr
index 3b4844ab1333d..f2f5dd0a0c841 100644
--- a/tests/ui/impl-trait/universal-two-impl-traits.stderr
+++ b/tests/ui/impl-trait/universal-two-impl-traits.stderr
@@ -10,8 +10,8 @@ LL |     let mut a = x;
 LL |     a = y;
    |         ^ expected type parameter `impl Debug`, found a different type parameter `impl Debug`
    |
-   = note: expected type parameter `impl Debug` (type parameter `impl Debug`)
-              found type parameter `impl Debug` (type parameter `impl Debug`)
+   = note: expected type parameter `impl Debug`
+              found type parameter `impl Debug`
    = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
    = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
 
diff --git a/tests/ui/stability-attribute/allowed-through-unstable.rs b/tests/ui/stability-attribute/allowed-through-unstable.rs
index e03417a4dae8d..5baa0fda94037 100644
--- a/tests/ui/stability-attribute/allowed-through-unstable.rs
+++ b/tests/ui/stability-attribute/allowed-through-unstable.rs
@@ -5,6 +5,5 @@
 
 extern crate allowed_through_unstable_core;
 
-use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstable;
-use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstableWithDeprecation; //~WARN use of deprecated module `allowed_through_unstable_core::unstable_module`: use the new path instead
+use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstable; //~WARN use of deprecated module `allowed_through_unstable_core::unstable_module`: use the new path instead
 use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowedThroughUnstable; //~ ERROR use of unstable library feature `unstable_test_feature`
diff --git a/tests/ui/stability-attribute/allowed-through-unstable.stderr b/tests/ui/stability-attribute/allowed-through-unstable.stderr
index 8d07b0cf9e8f3..bda68045002e4 100644
--- a/tests/ui/stability-attribute/allowed-through-unstable.stderr
+++ b/tests/ui/stability-attribute/allowed-through-unstable.stderr
@@ -1,13 +1,13 @@
 warning: use of deprecated module `allowed_through_unstable_core::unstable_module`: use the new path instead
-  --> $DIR/allowed-through-unstable.rs:9:53
+  --> $DIR/allowed-through-unstable.rs:8:53
    |
-LL | use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstableWithDeprecation;
-   |                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstable;
+   |                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(deprecated)]` on by default
 
 error[E0658]: use of unstable library feature `unstable_test_feature`
-  --> $DIR/allowed-through-unstable.rs:10:5
+  --> $DIR/allowed-through-unstable.rs:9:5
    |
 LL | use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowedThroughUnstable;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs b/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs
index 9dfbb451d04bb..23c722d6e8eba 100644
--- a/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs
+++ b/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs
@@ -5,13 +5,9 @@
 
 #[unstable(feature = "unstable_test_feature", issue = "1")]
 pub mod unstable_module {
-    #[stable(feature = "stable_test_feature", since = "1.2.0")]
-    #[rustc_allowed_through_unstable_modules]
-    pub trait OldStableTraitAllowedThoughUnstable {}
-
     #[stable(feature = "stable_test_feature", since = "1.2.0")]
     #[rustc_allowed_through_unstable_modules = "use the new path instead"]
-    pub trait OldStableTraitAllowedThoughUnstableWithDeprecation {}
+    pub trait OldStableTraitAllowedThoughUnstable {}
 
     #[stable(feature = "stable_test_feature", since = "1.2.0")]
     pub trait NewStableTraitNotAllowedThroughUnstable {}