15 files changed, 1481 insertions, 655 deletions

diff --git a/compiler/rustc_resolve/Cargo.toml b/compiler/rustc_resolve/Cargo.toml
index 7c3a0f8f2..5c4ec44d2 100644
--- a/compiler/rustc_resolve/Cargo.toml
+++ b/compiler/rustc_resolve/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 bitflags = "1.2.1"
+pulldown-cmark = { version = "0.9.2", default-features = false }
 rustc_arena = { path = "../rustc_arena" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
@@ -24,5 +25,5 @@ rustc_query_system = { path = "../rustc_query_system" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
-thin-vec = "0.2.8"
+thin-vec = "0.2.12"
 tracing = "0.1"
diff --git a/compiler/rustc_resolve/locales/en-US.ftl b/compiler/rustc_resolve/locales/en-US.ftl
new file mode 100644
index 000000000..817bb83ed
--- /dev/null
+++ b/compiler/rustc_resolve/locales/en-US.ftl
@@ -0,0 +1,211 @@
+resolve_parent_module_reset_for_binding =
+    parent module is reset for binding
+
+resolve_ampersand_used_without_explicit_lifetime_name =
+    `&` without an explicit lifetime name cannot be used here
+    .note = explicit lifetime name needed here
+
+resolve_underscore_lifetime_name_cannot_be_used_here =
+    `'_` cannot be used here
+    .note = `'_` is a reserved lifetime name
+
+resolve_crate_may_not_be_imported =
+    `$crate` may not be imported
+
+resolve_crate_root_imports_must_be_named_explicitly =
+    crate root imports need to be explicitly named: `use crate as name;`
+
+resolve_generic_params_from_outer_function =
+    can't use generic parameters from outer function
+    .label = use of generic parameter from outer function
+    .suggestion = try using a local generic parameter instead
+
+resolve_self_type_implicitly_declared_by_impl =
+    `Self` type implicitly declared here, by this `impl`
+
+resolve_cannot_use_self_type_here =
+    can't use `Self` here
+
+resolve_use_a_type_here_instead =
+    use a type here instead
+
+resolve_type_param_from_outer_fn =
+    type parameter from outer function
+
+resolve_const_param_from_outer_fn =
+    const parameter from outer function
+
+resolve_try_using_local_generic_parameter =
+    try using a local generic parameter instead
+
+resolve_try_adding_local_generic_param_on_method =
+    try adding a local generic parameter in this method instead
+
+resolve_help_try_using_local_generic_param =
+    try using a local generic paramter instead
+
+resolve_name_is_already_used_as_generic_parameter =
+    the name `{$name}` is already used for a generic parameter in this item's generic parameters
+    .label = already used
+    .first_use_of_name = first use of `{$name}`
+
+resolve_method_not_member_of_trait =
+    method `{$method}` is not a member of trait `{$trait_}`
+    .label = not a member of trait `{$trait_}`
+
+resolve_associated_fn_with_similar_name_exists =
+    there is an associated function with a similar name
+
+resolve_type_not_member_of_trait =
+    type `{$type_}` is not a member of trait `{$trait_}`
+    .label = not a member of trait `{$trait_}`
+
+resolve_associated_type_with_similar_name_exists =
+    there is an associated type with a similar name
+
+resolve_const_not_member_of_trait =
+    const `{$const_}` is not a member of trait `{$trait_}`
+    .label = not a member of trait `{$trait_}`
+
+resolve_associated_const_with_similar_name_exists =
+    there is an associated constant with a similar name
+
+resolve_variable_bound_with_different_mode =
+    variable `{$variable_name}` is bound inconsistently across alternatives separated by `|`
+    .label = bound in different ways
+    .first_binding_span = first binding
+
+resolve_ident_bound_more_than_once_in_parameter_list =
+    identifier `{$identifier}` is bound more than once in this parameter list
+    .label = used as parameter more than once
+
+resolve_ident_bound_more_than_once_in_same_pattern =
+    identifier `{$identifier}` is bound more than once in the same pattern
+    .label = used in a pattern more than once
+
+resolve_undeclared_label =
+    use of undeclared label `{$name}`
+    .label = undeclared label `{$name}`
+
+resolve_label_with_similar_name_reachable =
+    a label with a similar name is reachable
+
+resolve_try_using_similarly_named_label =
+    try using similarly named label
+
+resolve_unreachable_label_with_similar_name_exists =
+    a label with a similar name exists but is unreachable
+
+resolve_self_import_can_only_appear_once_in_the_list =
+    `self` import can only appear once in an import list
+    .label = can only appear once in an import list
+
+resolve_self_import_only_in_import_list_with_non_empty_prefix =
+    `self` import can only appear in an import list with a non-empty prefix
+    .label = can only appear in an import list with a non-empty prefix
+
+resolve_cannot_capture_dynamic_environment_in_fn_item =
+    can't capture dynamic environment in a fn item
+    .help = use the `|| {"{"} ... {"}"}` closure form instead
+
+resolve_attempt_to_use_non_constant_value_in_constant =
+    attempt to use a non-constant value in a constant
+
+resolve_attempt_to_use_non_constant_value_in_constant_with_suggestion =
+    consider using `{$suggestion}` instead of `{$current}`
+
+resolve_attempt_to_use_non_constant_value_in_constant_label_with_suggestion =
+    non-constant value
+
+resolve_attempt_to_use_non_constant_value_in_constant_without_suggestion =
+    this would need to be a `{$suggestion}`
+
+resolve_self_imports_only_allowed_within =
+    `self` imports are only allowed within a {"{"} {"}"} list
+
+resolve_self_imports_only_allowed_within_suggestion =
+    consider importing the module directly
+
+resolve_self_imports_only_allowed_within_multipart_suggestion =
+    alternatively, use the multi-path `use` syntax to import `self`
+
+resolve_binding_shadows_something_unacceptable =
+    {$shadowing_binding}s cannot shadow {$shadowed_binding}s
+    .label = cannot be named the same as {$article} {$shadowed_binding}
+    .label_shadowed_binding = the {$shadowed_binding} `{$name}` is {$participle} here
+
+resolve_binding_shadows_something_unacceptable_suggestion =
+    try specify the pattern arguments
+
+resolve_forward_declared_generic_param =
+    generic parameters with a default cannot use forward declared identifiers
+    .label = defaulted generic parameters cannot be forward declared
+
+resolve_param_in_ty_of_const_param =
+    the type of const parameters must not depend on other generic parameters
+    .label = the type must not depend on the parameter `{$name}`
+
+resolve_self_in_generic_param_default =
+    generic parameters cannot use `Self` in their defaults
+    .label = `Self` in generic parameter default
+
+resolve_param_in_non_trivial_anon_const =
+    generic parameters may not be used in const operations
+    .label = cannot perform const operation using `{$name}`
+
+resolve_param_in_non_trivial_anon_const_help =
+    use `#![feature(generic_const_exprs)]` to allow generic const expressions
+
+resolve_param_in_non_trivial_anon_const_sub_type =
+    type parameters may not be used in const expressions
+
+resolve_param_in_non_trivial_anon_const_sub_non_type =
+    const parameters may only be used as standalone arguments, i.e. `{$name}`
+
+resolve_unreachable_label =
+    use of unreachable label `{$name}`
+    .label = unreachable label `{$name}`
+    .label_definition_span = unreachable label defined here
+    .note = labels are unreachable through functions, closures, async blocks and modules
+
+resolve_unreachable_label_suggestion_use_similarly_named =
+    try using similarly named label
+
+resolve_unreachable_label_similar_name_reachable =
+    a label with a similar name is reachable
+
+resolve_unreachable_label_similar_name_unreachable =
+    a label with a similar name exists but is also unreachable
+
+resolve_trait_impl_mismatch =
+    item `{$name}` is an associated {$kind}, which doesn't match its trait `{$trait_path}`
+    .label = does not match trait
+    .label_trait_item = item in trait
+
+resolve_invalid_asm_sym =
+    invalid `sym` operand
+    .label = is a local variable
+    .help = `sym` operands must refer to either a function or a static
+
+resolve_trait_impl_duplicate =
+    duplicate definitions with name `{$name}`:
+    .label = duplicate definition
+    .old_span_label = previous definition here
+    .trait_item_span = item in trait
+
+resolve_relative_2018 =
+    relative paths are not supported in visibilities in 2018 edition or later
+    .suggestion = try
+
+resolve_ancestor_only =
+    visibilities can only be restricted to ancestor modules
+
+resolve_expected_found =
+    expected module, found {$res} `{$path_str}`
+    .label = not a module
+
+resolve_indeterminate =
+    cannot determine resolution for the visibility
+
+resolve_module_only =
+    visibility must resolve to a module
diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index b1b04c92a..b1e023f2c 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -65,7 +65,7 @@ impl<'a, Id: Into<DefId>> ToNameBinding<'a> for (Res, ty::Visibility<Id>, Span,
     }
 }
 
-impl<'a> Resolver<'a> {
+impl<'a, 'tcx> Resolver<'a, 'tcx> {
     /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
     /// otherwise, reports an error.
     pub(crate) fn define<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
@@ -95,7 +95,7 @@ impl<'a> Resolver<'a> {
     /// Reachable macros with block module parents exist due to `#[macro_export] macro_rules!`,
     /// but they cannot use def-site hygiene, so the assumption holds
     /// (<https://github.com/rust-lang/rust/pull/77984#issuecomment-712445508>).
-    pub fn get_nearest_non_block_module(&mut self, mut def_id: DefId) -> Module<'a> {
+    pub(crate) fn get_nearest_non_block_module(&mut self, mut def_id: DefId) -> Module<'a> {
         loop {
             match self.get_module(def_id) {
                 Some(module) => return module,
@@ -104,7 +104,7 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    pub fn expect_module(&mut self, def_id: DefId) -> Module<'a> {
+    pub(crate) fn expect_module(&mut self, def_id: DefId) -> Module<'a> {
         self.get_module(def_id).expect("argument `DefId` is not a module")
     }
 
@@ -130,11 +130,13 @@ impl<'a> Resolver<'a> {
                         def_key.disambiguated_data.data.get_opt_name().expect("module without name")
                     };
 
+                    let expn_id = self.cstore().module_expansion_untracked(def_id, &self.tcx.sess);
+                    let span = self.cstore().get_span_untracked(def_id, &self.tcx.sess);
                     Some(self.new_module(
                         parent,
                         ModuleKind::Def(def_kind, def_id, name),
-                        self.cstore().module_expansion_untracked(def_id, &self.session),
-                        self.cstore().get_span_untracked(def_id, &self.session),
+                        expn_id,
+                        span,
                         // FIXME: Account for `#[no_implicit_prelude]` attributes.
                         parent.map_or(false, |module| module.no_implicit_prelude),
                     ))
@@ -179,7 +181,8 @@ impl<'a> Resolver<'a> {
             return macro_data.clone();
         }
 
-        let (ext, macro_rules) = match self.cstore().load_macro_untracked(def_id, &self.session) {
+        let load_macro_untracked = self.cstore().load_macro_untracked(def_id, &self.tcx.sess);
+        let (ext, macro_rules) = match load_macro_untracked {
             LoadedMacro::MacroDef(item, edition) => (
                 Lrc::new(self.compile_macro(&item, edition).0),
                 matches!(item.kind, ItemKind::MacroDef(def) if def.macro_rules),
@@ -204,9 +207,9 @@ impl<'a> Resolver<'a> {
     }
 
     pub(crate) fn build_reduced_graph_external(&mut self, module: Module<'a>) {
-        for child in
-            Vec::from_iter(self.cstore().module_children_untracked(module.def_id(), self.session))
-        {
+        let children =
+            Vec::from_iter(self.cstore().module_children_untracked(module.def_id(), self.tcx.sess));
+        for child in children {
             let parent_scope = ParentScope::module(module, self);
             BuildReducedGraphVisitor { r: self, parent_scope }
                 .build_reduced_graph_for_external_crate_res(child);
@@ -214,18 +217,18 @@ impl<'a> Resolver<'a> {
     }
 }
 
-struct BuildReducedGraphVisitor<'a, 'b> {
-    r: &'b mut Resolver<'a>,
+struct BuildReducedGraphVisitor<'a, 'b, 'tcx> {
+    r: &'b mut Resolver<'a, 'tcx>,
     parent_scope: ParentScope<'a>,
 }
 
-impl<'a> AsMut<Resolver<'a>> for BuildReducedGraphVisitor<'a, '_> {
-    fn as_mut(&mut self) -> &mut Resolver<'a> {
+impl<'a, 'tcx> AsMut<Resolver<'a, 'tcx>> for BuildReducedGraphVisitor<'a, '_, 'tcx> {
+    fn as_mut(&mut self) -> &mut Resolver<'a, 'tcx> {
         self.r
     }
 }
 
-impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
+impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
     fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
         self.try_resolve_visibility(vis, true).unwrap_or_else(|err| {
             self.r.report_vis_error(err);
@@ -265,7 +268,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 let ident = path.segments.get(0).expect("empty path in visibility").ident;
                 let crate_root = if ident.is_path_segment_keyword() {
                     None
-                } else if ident.span.rust_2015() {
+                } else if ident.span.is_rust_2015() {
                     Some(Segment::from_ident(Ident::new(
                         kw::PathRoot,
                         path.span.shrink_to_lo().with_ctxt(ident.span.ctxt()),
@@ -298,14 +301,15 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                             self.r.record_partial_res(id, PartialRes::new(res));
                         }
                         if module.is_normal() {
-                            if res == Res::Err {
-                                Ok(ty::Visibility::Public)
-                            } else {
-                                let vis = ty::Visibility::Restricted(res.def_id());
-                                if self.r.is_accessible_from(vis, parent_scope.module) {
-                                    Ok(vis.expect_local())
-                                } else {
-                                    Err(VisResolutionError::AncestorOnly(path.span))
+                            match res {
+                                Res::Err => Ok(ty::Visibility::Public),
+                                _ => {
+                                    let vis = ty::Visibility::Restricted(res.def_id());
+                                    if self.r.is_accessible_from(vis, parent_scope.module) {
+                                        Ok(vis.expect_local())
+                                    } else {
+                                        Err(VisResolutionError::AncestorOnly(path.span))
+                                    }
                                 }
                             }
                         } else {
@@ -345,7 +349,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
 
     fn insert_field_names_extern(&mut self, def_id: DefId) {
         let field_names =
-            self.r.cstore().struct_field_names_untracked(def_id, self.r.session).collect();
+            self.r.cstore().struct_field_names_untracked(def_id, self.r.tcx.sess).collect();
         self.r.field_names.insert(def_id, field_names);
     }
 
@@ -434,10 +438,10 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         // appears, so imports in braced groups can have roots prepended independently.
         let is_glob = matches!(use_tree.kind, ast::UseTreeKind::Glob);
         let crate_root = match prefix_iter.peek() {
-            Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.rust_2015() => {
+            Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.is_rust_2015() => {
                 Some(seg.ident.span.ctxt())
             }
-            None if is_glob && use_tree.span.rust_2015() => Some(use_tree.span.ctxt()),
+            None if is_glob && use_tree.span.is_rust_2015() => Some(use_tree.span.ctxt()),
             _ => None,
         }
         .map(|ctxt| {
@@ -538,14 +542,15 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         }
 
                         self.r
-                            .session
+                            .tcx
+                            .sess
                             .struct_span_err(item.span, "`$crate` may not be imported")
                             .emit();
                     }
                 }
 
                 if ident.name == kw::Crate {
-                    self.r.session.span_err(
+                    self.r.tcx.sess.span_err(
                         ident.span,
                         "crate root imports need to be explicitly named: \
                          `use crate as name;`",
@@ -574,7 +579,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             }
             ast::UseTreeKind::Glob => {
                 let kind = ImportKind::Glob {
-                    is_prelude: self.r.session.contains_name(&item.attrs, sym::prelude_import),
+                    is_prelude: self.r.tcx.sess.contains_name(&item.attrs, sym::prelude_import),
                     max_vis: Cell::new(None),
                     id,
                 };
@@ -689,7 +694,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     expansion.to_expn_id(),
                     item.span,
                     parent.no_implicit_prelude
-                        || self.r.session.contains_name(&item.attrs, sym::no_implicit_prelude),
+                        || self.r.tcx.sess.contains_name(&item.attrs, sym::no_implicit_prelude),
                 );
                 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
 
@@ -754,7 +759,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     // If the structure is marked as non_exhaustive then lower the visibility
                     // to within the crate.
                     let mut ctor_vis = if vis.is_public()
-                        && self.r.session.contains_name(&item.attrs, sym::non_exhaustive)
+                        && self.r.tcx.sess.contains_name(&item.attrs, sym::non_exhaustive)
                     {
                         ty::Visibility::Restricted(CRATE_DEF_ID)
                     } else {
@@ -836,7 +841,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
 
         let (used, module, binding) = if orig_name.is_none() && ident.name == kw::SelfLower {
             self.r
-                .session
+                .tcx
+                .sess
                 .struct_span_err(item.span, "`extern crate self;` requires renaming")
                 .span_suggestion(
                     item.span,
@@ -849,7 +855,10 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         } else if orig_name == Some(kw::SelfLower) {
             Some(self.r.graph_root)
         } else {
-            let crate_id = self.r.crate_loader().process_extern_crate(item, local_def_id);
+            let tcx = self.r.tcx;
+            let crate_id = self.r.crate_loader(|c| {
+                c.process_extern_crate(item, local_def_id, &tcx.definitions_untracked())
+            });
             crate_id.map(|crate_id| {
                 self.r.extern_crate_map.insert(local_def_id, crate_id);
                 self.r.expect_module(crate_id.as_def_id())
@@ -886,7 +895,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 {
                     let msg = "macro-expanded `extern crate` items cannot \
                                        shadow names passed with `--extern`";
-                    self.r.session.span_err(item.span, msg);
+                    self.r.tcx.sess.span_err(item.span, msg);
                 }
             }
             let entry = self.r.extern_prelude.entry(ident.normalize_to_macros_2_0()).or_insert(
@@ -986,7 +995,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 | DefKind::LifetimeParam
                 | DefKind::GlobalAsm
                 | DefKind::Closure
-                | DefKind::Impl
+                | DefKind::Impl { .. }
                 | DefKind::Generator,
                 _,
             )
@@ -997,23 +1006,26 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             | Res::Err => bug!("unexpected resolution: {:?}", res),
         }
         // Record some extra data for better diagnostics.
-        let cstore = self.r.cstore();
         match res {
             Res::Def(DefKind::Struct, def_id) => {
+                let cstore = self.r.cstore();
                 if let Some((ctor_kind, ctor_def_id)) = cstore.ctor_untracked(def_id) {
                     let ctor_res = Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id);
                     let ctor_vis = cstore.visibility_untracked(ctor_def_id);
                     let field_visibilities =
                         cstore.struct_field_visibilities_untracked(def_id).collect();
+                    drop(cstore);
                     self.r
                         .struct_constructors
                         .insert(def_id, (ctor_res, ctor_vis, field_visibilities));
+                } else {
+                    drop(cstore);
                 }
                 self.insert_field_names_extern(def_id)
             }
             Res::Def(DefKind::Union, def_id) => self.insert_field_names_extern(def_id),
             Res::Def(DefKind::AssocFn, def_id) => {
-                if cstore.fn_has_self_parameter_untracked(def_id, self.r.session) {
+                if self.r.cstore().fn_has_self_parameter_untracked(def_id, self.r.tcx.sess) {
                     self.r.has_self.insert(def_id);
                 }
             }
@@ -1032,7 +1044,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             let msg = format!("`{}` is already in scope", name);
             let note =
                 "macro-expanded `#[macro_use]`s may not shadow existing macros (see RFC 1560)";
-            self.r.session.struct_span_err(span, &msg).note(note).emit();
+            self.r.tcx.sess.struct_span_err(span, &msg).note(note).emit();
         }
     }
 
@@ -1044,7 +1056,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             if attr.has_name(sym::macro_use) {
                 if self.parent_scope.module.parent.is_some() {
                     struct_span_err!(
-                        self.r.session,
+                        self.r.tcx.sess,
                         item.span,
                         E0468,
                         "an `extern crate` loading macros must be at the crate root"
@@ -1054,7 +1066,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 if let ItemKind::ExternCrate(Some(orig_name)) = item.kind {
                     if orig_name == kw::SelfLower {
                         self.r
-                            .session
+                            .tcx
+                            .sess
                             .struct_span_err(
                                 attr.span,
                                 "`#[macro_use]` is not supported on `extern crate self`",
@@ -1063,7 +1076,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     }
                 }
                 let ill_formed = |span| {
-                    struct_span_err!(self.r.session, span, E0466, "bad macro import").emit();
+                    struct_span_err!(self.r.tcx.sess, span, E0466, "bad macro import").emit();
                 };
                 match attr.meta() {
                     Some(meta) => match meta.kind {
@@ -1134,8 +1147,13 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         allow_shadowing,
                     );
                 } else {
-                    struct_span_err!(self.r.session, ident.span, E0469, "imported macro not found")
-                        .emit();
+                    struct_span_err!(
+                        self.r.tcx.sess,
+                        ident.span,
+                        E0469,
+                        "imported macro not found"
+                    )
+                    .emit();
                 }
             }
         }
@@ -1147,7 +1165,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         for attr in attrs {
             if attr.has_name(sym::macro_escape) {
                 let msg = "`#[macro_escape]` is a deprecated synonym for `#[macro_use]`";
-                let mut err = self.r.session.struct_span_warn(attr.span, msg);
+                let mut err = self.r.tcx.sess.struct_span_warn(attr.span, msg);
                 if let ast::AttrStyle::Inner = attr.style {
                     err.help("try an outer attribute: `#[macro_use]`").emit();
                 } else {
@@ -1158,7 +1176,10 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             }
 
             if !attr.is_word() {
-                self.r.session.span_err(attr.span, "arguments to `macro_use` are not allowed here");
+                self.r
+                    .tcx
+                    .sess
+                    .span_err(attr.span, "arguments to `macro_use` are not allowed here");
             }
             return true;
         }
@@ -1182,11 +1203,11 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
     }
 
     fn proc_macro_stub(&self, item: &ast::Item) -> Option<(MacroKind, Ident, Span)> {
-        if self.r.session.contains_name(&item.attrs, sym::proc_macro) {
+        if self.r.tcx.sess.contains_name(&item.attrs, sym::proc_macro) {
             return Some((MacroKind::Bang, item.ident, item.span));
-        } else if self.r.session.contains_name(&item.attrs, sym::proc_macro_attribute) {
+        } else if self.r.tcx.sess.contains_name(&item.attrs, sym::proc_macro_attribute) {
             return Some((MacroKind::Attr, item.ident, item.span));
-        } else if let Some(attr) = self.r.session.find_by_name(&item.attrs, sym::proc_macro_derive)
+        } else if let Some(attr) = self.r.tcx.sess.find_by_name(&item.attrs, sym::proc_macro_derive)
         {
             if let Some(nested_meta) = attr.meta_item_list().and_then(|list| list.get(0).cloned()) {
                 if let Some(ident) = nested_meta.ident() {
@@ -1221,7 +1242,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         let def_id = self.r.local_def_id(item.id);
         let (ext, ident, span, macro_rules, rule_spans) = match &item.kind {
             ItemKind::MacroDef(def) => {
-                let (ext, rule_spans) = self.r.compile_macro(item, self.r.session.edition());
+                let (ext, rule_spans) = self.r.compile_macro(item, self.r.tcx.sess.edition());
                 let ext = Lrc::new(ext);
                 (ext, item.ident, item.span, def.macro_rules, rule_spans)
             }
@@ -1242,7 +1263,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         if macro_rules {
             let ident = ident.normalize_to_macros_2_0();
             self.r.macro_names.insert(ident);
-            let is_macro_export = self.r.session.contains_name(&item.attrs, sym::macro_export);
+            let is_macro_export = self.r.tcx.sess.contains_name(&item.attrs, sym::macro_export);
             let vis = if is_macro_export {
                 ty::Visibility::Public
             } else {
@@ -1250,6 +1271,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             };
             let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas);
             self.r.set_binding_parent_module(binding, parent_scope.module);
+            self.r.all_macro_rules.insert(ident.name, res);
             if is_macro_export {
                 let import = self.r.arenas.alloc_import(Import {
                     kind: ImportKind::MacroExport,
@@ -1313,7 +1335,7 @@ macro_rules! method {
     };
 }
 
-impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
+impl<'a, 'b, 'tcx> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b, 'tcx> {
     method!(visit_expr: ast::Expr, ast::ExprKind::MacCall, walk_expr);
     method!(visit_pat: ast::Pat, ast::PatKind::MacCall, walk_pat);
     method!(visit_ty: ast::Ty, ast::TyKind::MacCall, walk_ty);
@@ -1505,7 +1527,7 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
 
         // If the variant is marked as non_exhaustive then lower the visibility to within the crate.
         let ctor_vis = if vis.is_public()
-            && self.r.session.contains_name(&variant.attrs, sym::non_exhaustive)
+            && self.r.tcx.sess.contains_name(&variant.attrs, sym::non_exhaustive)
         {
             ty::Visibility::Restricted(CRATE_DEF_ID)
         } else {
diff --git a/compiler/rustc_resolve/src/check_unused.rs b/compiler/rustc_resolve/src/check_unused.rs
index eae4c9992..b2578e4c4 100644
--- a/compiler/rustc_resolve/src/check_unused.rs
+++ b/compiler/rustc_resolve/src/check_unused.rs
@@ -29,11 +29,12 @@ use crate::Resolver;
 
 use rustc_ast as ast;
 use rustc_ast::visit::{self, Visitor};
-use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::unord::UnordSet;
 use rustc_errors::{pluralize, MultiSpan};
-use rustc_session::lint::builtin::{MACRO_USE_EXTERN_CRATE, UNUSED_IMPORTS};
+use rustc_session::lint::builtin::{MACRO_USE_EXTERN_CRATE, UNUSED_EXTERN_CRATES, UNUSED_IMPORTS};
 use rustc_session::lint::BuiltinLintDiagnostics;
+use rustc_span::symbol::Ident;
 use rustc_span::{Span, DUMMY_SP};
 
 struct UnusedImport<'a> {
@@ -49,16 +50,33 @@ impl<'a> UnusedImport<'a> {
     }
 }
 
-struct UnusedImportCheckVisitor<'a, 'b> {
-    r: &'a mut Resolver<'b>,
+struct UnusedImportCheckVisitor<'a, 'b, 'tcx> {
+    r: &'a mut Resolver<'b, 'tcx>,
     /// All the (so far) unused imports, grouped path list
     unused_imports: FxIndexMap<ast::NodeId, UnusedImport<'a>>,
+    extern_crate_items: Vec<ExternCrateToLint>,
     base_use_tree: Option<&'a ast::UseTree>,
     base_id: ast::NodeId,
     item_span: Span,
 }
 
-impl<'a, 'b> UnusedImportCheckVisitor<'a, 'b> {
+struct ExternCrateToLint {
+    id: ast::NodeId,
+    /// Span from the item
+    span: Span,
+    /// Span to use to suggest complete removal.
+    span_with_attributes: Span,
+    /// Span of the visibility, if any.
+    vis_span: Span,
+    /// Whether the item has attrs.
+    has_attrs: bool,
+    /// Name used to refer to the crate.
+    ident: Ident,
+    /// Whether the statement renames the crate `extern crate orig_name as new_name;`.
+    renames: bool,
+}
+
+impl<'a, 'b, 'tcx> UnusedImportCheckVisitor<'a, 'b, 'tcx> {
     // We have information about whether `use` (import) items are actually
     // used now. If an import is not used at all, we signal a lint error.
     fn check_import(&mut self, id: ast::NodeId) {
@@ -94,20 +112,29 @@ impl<'a, 'b> UnusedImportCheckVisitor<'a, 'b> {
     }
 }
 
-impl<'a, 'b> Visitor<'a> for UnusedImportCheckVisitor<'a, 'b> {
+impl<'a, 'b, 'tcx> Visitor<'a> for UnusedImportCheckVisitor<'a, 'b, 'tcx> {
     fn visit_item(&mut self, item: &'a ast::Item) {
-        self.item_span = item.span_with_attributes();
-
-        // Ignore is_public import statements because there's no way to be sure
-        // whether they're used or not. Also ignore imports with a dummy span
-        // because this means that they were generated in some fashion by the
-        // compiler and we don't need to consider them.
-        if let ast::ItemKind::Use(..) = item.kind {
-            if item.vis.kind.is_pub() || item.span.is_dummy() {
-                return;
+        match item.kind {
+            // Ignore is_public import statements because there's no way to be sure
+            // whether they're used or not. Also ignore imports with a dummy span
+            // because this means that they were generated in some fashion by the
+            // compiler and we don't need to consider them.
+            ast::ItemKind::Use(..) if item.vis.kind.is_pub() || item.span.is_dummy() => return,
+            ast::ItemKind::ExternCrate(orig_name) => {
+                self.extern_crate_items.push(ExternCrateToLint {
+                    id: item.id,
+                    span: item.span,
+                    vis_span: item.vis.span,
+                    span_with_attributes: item.span_with_attributes(),
+                    has_attrs: !item.attrs.is_empty(),
+                    ident: item.ident,
+                    renames: orig_name.is_some(),
+                });
             }
+            _ => {}
         }
 
+        self.item_span = item.span_with_attributes();
         visit::walk_item(self, item);
     }
 
@@ -222,8 +249,11 @@ fn calc_unused_spans(
     }
 }
 
-impl Resolver<'_> {
+impl Resolver<'_, '_> {
     pub(crate) fn check_unused(&mut self, krate: &ast::Crate) {
+        let tcx = self.tcx;
+        let mut maybe_unused_extern_crates = FxHashMap::default();
+
         for import in self.potentially_unused_imports.iter() {
             match import.kind {
                 _ if import.used.get()
@@ -246,7 +276,14 @@ impl Resolver<'_> {
                 }
                 ImportKind::ExternCrate { id, .. } => {
                     let def_id = self.local_def_id(id);
-                    self.maybe_unused_extern_crates.push((def_id, import.span));
+                    if self.extern_crate_map.get(&def_id).map_or(true, |&cnum| {
+                        !tcx.is_compiler_builtins(cnum)
+                            && !tcx.is_panic_runtime(cnum)
+                            && !tcx.has_global_allocator(cnum)
+                            && !tcx.has_panic_handler(cnum)
+                    }) {
+                        maybe_unused_extern_crates.insert(id, import.span);
+                    }
                 }
                 ImportKind::MacroUse => {
                     let msg = "unused `#[macro_use]` import";
@@ -259,6 +296,7 @@ impl Resolver<'_> {
         let mut visitor = UnusedImportCheckVisitor {
             r: self,
             unused_imports: Default::default(),
+            extern_crate_items: Default::default(),
             base_use_tree: None,
             base_id: ast::DUMMY_NODE_ID,
             item_span: DUMMY_SP,
@@ -290,7 +328,7 @@ impl Resolver<'_> {
             let ms = MultiSpan::from_spans(spans.clone());
             let mut span_snippets = spans
                 .iter()
-                .filter_map(|s| match visitor.r.session.source_map().span_to_snippet(*s) {
+                .filter_map(|s| match tcx.sess.source_map().span_to_snippet(*s) {
                     Ok(s) => Some(format!("`{}`", s)),
                     _ => None,
                 })
@@ -317,7 +355,7 @@ impl Resolver<'_> {
             // If we are in the `--test` mode, suppress a help that adds the `#[cfg(test)]`
             // attribute; however, if not, suggest adding the attribute. There is no way to
             // retrieve attributes here because we do not have a `TyCtxt` yet.
-            let test_module_span = if visitor.r.session.opts.test {
+            let test_module_span = if tcx.sess.opts.test {
                 None
             } else {
                 let parent_module = visitor.r.get_nearest_non_block_module(
@@ -346,5 +384,74 @@ impl Resolver<'_> {
                 BuiltinLintDiagnostics::UnusedImports(fix_msg.into(), fixes, test_module_span),
             );
         }
+
+        for extern_crate in visitor.extern_crate_items {
+            let warn_if_unused = !extern_crate.ident.name.as_str().starts_with('_');
+
+            // If the crate is fully unused, we suggest removing it altogether.
+            // We do this in any edition.
+            if warn_if_unused {
+                if let Some(&span) = maybe_unused_extern_crates.get(&extern_crate.id) {
+                    visitor.r.lint_buffer.buffer_lint_with_diagnostic(
+                        UNUSED_EXTERN_CRATES,
+                        extern_crate.id,
+                        span,
+                        "unused extern crate",
+                        BuiltinLintDiagnostics::UnusedExternCrate {
+                            removal_span: extern_crate.span_with_attributes,
+                        },
+                    );
+                    continue;
+                }
+            }
+
+            // If we are not in Rust 2018 edition, then we don't make any further
+            // suggestions.
+            if !tcx.sess.rust_2018() {
+                continue;
+            }
+
+            // If the extern crate has any attributes, they may have funky
+            // semantics we can't faithfully represent using `use` (most
+            // notably `#[macro_use]`). Ignore it.
+            if extern_crate.has_attrs {
+                continue;
+            }
+
+            // If the extern crate is renamed, then we cannot suggest replacing it with a use as this
+            // would not insert the new name into the prelude, where other imports in the crate may be
+            // expecting it.
+            if extern_crate.renames {
+                continue;
+            }
+
+            // If the extern crate isn't in the extern prelude,
+            // there is no way it can be written as a `use`.
+            if !visitor
+                .r
+                .extern_prelude
+                .get(&extern_crate.ident)
+                .map_or(false, |entry| !entry.introduced_by_item)
+            {
+                continue;
+            }
+
+            let vis_span = extern_crate
+                .vis_span
+                .find_ancestor_inside(extern_crate.span)
+                .unwrap_or(extern_crate.vis_span);
+            let ident_span = extern_crate
+                .ident
+                .span
+                .find_ancestor_inside(extern_crate.span)
+                .unwrap_or(extern_crate.ident.span);
+            visitor.r.lint_buffer.buffer_lint_with_diagnostic(
+                UNUSED_EXTERN_CRATES,
+                extern_crate.id,
+                extern_crate.span,
+                "`extern crate` is not idiomatic in the new edition",
+                BuiltinLintDiagnostics::ExternCrateNotIdiomatic { vis_span, ident_span },
+            );
+        }
     }
 }
diff --git a/compiler/rustc_resolve/src/def_collector.rs b/compiler/rustc_resolve/src/def_collector.rs
index 2764a6c28..e7ff236f8 100644
--- a/compiler/rustc_resolve/src/def_collector.rs
+++ b/compiler/rustc_resolve/src/def_collector.rs
@@ -9,7 +9,7 @@ use rustc_span::symbol::sym;
 use rustc_span::Span;
 
 pub(crate) fn collect_definitions(
-    resolver: &mut Resolver<'_>,
+    resolver: &mut Resolver<'_, '_>,
     fragment: &AstFragment,
     expansion: LocalExpnId,
 ) {
@@ -18,14 +18,14 @@ pub(crate) fn collect_definitions(
 }
 
 /// Creates `DefId`s for nodes in the AST.
-struct DefCollector<'a, 'b> {
-    resolver: &'a mut Resolver<'b>,
+struct DefCollector<'a, 'b, 'tcx> {
+    resolver: &'a mut Resolver<'b, 'tcx>,
     parent_def: LocalDefId,
     impl_trait_context: ImplTraitContext,
     expansion: LocalExpnId,
 }
 
-impl<'a, 'b> DefCollector<'a, 'b> {
+impl<'a, 'b, 'tcx> DefCollector<'a, 'b, 'tcx> {
     fn create_def(&mut self, node_id: NodeId, data: DefPathData, span: Span) -> LocalDefId {
         let parent_def = self.parent_def;
         debug!("create_def(node_id={:?}, data={:?}, parent_def={:?})", node_id, data, parent_def);
@@ -81,7 +81,7 @@ impl<'a, 'b> DefCollector<'a, 'b> {
     }
 }
 
-impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
+impl<'a, 'b, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'b, 'tcx> {
     fn visit_item(&mut self, i: &'a Item) {
         debug!("visit_item: {:?}", i);
 
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 366086152..7add59ac6 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -12,25 +12,24 @@ use rustc_errors::{struct_span_err, SuggestionStyle};
 use rustc_feature::BUILTIN_ATTRIBUTES;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind, PerNS};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::PrimTy;
-use rustc_index::vec::IndexVec;
 use rustc_middle::bug;
-use rustc_middle::ty::DefIdTree;
+use rustc_middle::ty::{DefIdTree, TyCtxt};
 use rustc_session::lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE;
 use rustc_session::lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS;
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::Session;
+use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::MacroKind;
-use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Span, SyntaxContext};
 use thin_vec::ThinVec;
 
 use crate::errors as errs;
-use crate::imports::{Import, ImportKind, ImportResolver};
+use crate::imports::{Import, ImportKind};
 use crate::late::{PatternSource, Rib};
 use crate::path_names_to_string;
 use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, BindingError, Finalize};
@@ -114,7 +113,7 @@ fn reduce_impl_span_to_impl_keyword(sm: &SourceMap, impl_span: Span) -> Span {
     sm.span_until_whitespace(impl_span)
 }
 
-impl<'a> Resolver<'a> {
+impl<'a, 'tcx> Resolver<'a, 'tcx> {
     pub(crate) fn report_errors(&mut self, krate: &Crate) {
         self.report_with_use_injections(krate);
 
@@ -154,8 +153,7 @@ impl<'a> Resolver<'a> {
 
             if !candidates.is_empty() {
                 show_candidates(
-                    &self.session,
-                    &self.untracked.source_span,
+                    self.tcx,
                     &mut err,
                     span,
                     &candidates,
@@ -191,6 +189,8 @@ impl<'a> Resolver<'a> {
         }
 
         let container = match parent.kind {
+            // Avoid using TyCtxt::def_kind_descr in the resolver, because it
+            // indirectly *calls* the resolver, and would cause a query cycle.
             ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id()),
             ModuleKind::Block => "block",
         };
@@ -206,7 +206,7 @@ impl<'a> Resolver<'a> {
         };
 
         let (name, span) =
-            (ident.name, self.session.source_map().guess_head_span(new_binding.span));
+            (ident.name, self.tcx.sess.source_map().guess_head_span(new_binding.span));
 
         if let Some(s) = self.name_already_seen.get(&name) {
             if s == &span {
@@ -226,15 +226,15 @@ impl<'a> Resolver<'a> {
         let msg = format!("the name `{}` is defined multiple times", name);
 
         let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
-            (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
+            (true, true) => struct_span_err!(self.tcx.sess, span, E0259, "{}", msg),
             (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
-                true => struct_span_err!(self.session, span, E0254, "{}", msg),
-                false => struct_span_err!(self.session, span, E0260, "{}", msg),
+                true => struct_span_err!(self.tcx.sess, span, E0254, "{}", msg),
+                false => struct_span_err!(self.tcx.sess, span, E0260, "{}", msg),
             },
             _ => match (old_binding.is_import_user_facing(), new_binding.is_import_user_facing()) {
-                (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
-                (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
-                _ => struct_span_err!(self.session, span, E0255, "{}", msg),
+                (false, false) => struct_span_err!(self.tcx.sess, span, E0428, "{}", msg),
+                (true, true) => struct_span_err!(self.tcx.sess, span, E0252, "{}", msg),
+                _ => struct_span_err!(self.tcx.sess, span, E0255, "{}", msg),
             },
         };
 
@@ -248,7 +248,7 @@ impl<'a> Resolver<'a> {
         err.span_label(span, format!("`{}` re{} here", name, new_participle));
         if !old_binding.span.is_dummy() && old_binding.span != span {
             err.span_label(
-                self.session.source_map().guess_head_span(old_binding.span),
+                self.tcx.sess.source_map().guess_head_span(old_binding.span),
                 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
             );
         }
@@ -352,7 +352,7 @@ impl<'a> Resolver<'a> {
                 if let Some(pos) =
                     source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
                 {
-                    if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
+                    if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(binding_span) {
                         if pos <= snippet.len() {
                             suggestion = Some(format!(
                                 "{} as {}{}",
@@ -426,12 +426,12 @@ impl<'a> Resolver<'a> {
         //   `a` and `import.use_span` is `issue_52891::{d, e, a};`.
 
         let (found_closing_brace, span) =
-            find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
+            find_span_of_binding_until_next_binding(self.tcx.sess, binding_span, import.use_span);
 
         // If there was a closing brace then identify the span to remove any trailing commas from
         // previous imports.
         if found_closing_brace {
-            if let Some(span) = extend_span_to_previous_binding(self.session, span) {
+            if let Some(span) = extend_span_to_previous_binding(self.tcx.sess, span) {
                 err.tool_only_span_suggestion(span, message, "", Applicability::MaybeIncorrect);
             } else {
                 // Remove the entire line if we cannot extend the span back, this indicates an
@@ -462,7 +462,9 @@ impl<'a> Resolver<'a> {
 
         let first_name = match path.get(0) {
             // In the 2018 edition this lint is a hard error, so nothing to do
-            Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
+            Some(seg) if seg.ident.span.is_rust_2015() && self.tcx.sess.is_rust_2015() => {
+                seg.ident.name
+            }
             _ => return,
         };
 
@@ -539,14 +541,14 @@ impl<'a> Resolver<'a> {
         match resolution_error {
             ResolutionError::GenericParamsFromOuterFunction(outer_res, has_generic_params) => {
                 let mut err = struct_span_err!(
-                    self.session,
+                    self.tcx.sess,
                     span,
                     E0401,
                     "can't use generic parameters from outer function",
                 );
                 err.span_label(span, "use of generic parameter from outer function");
 
-                let sm = self.session.source_map();
+                let sm = self.tcx.sess.source_map();
                 let def_id = match outer_res {
                     Res::SelfTyParam { .. } => {
                         err.span_label(span, "can't use `Self` here");
@@ -603,10 +605,11 @@ impl<'a> Resolver<'a> {
                 err
             }
             ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => self
-                .session
+                .tcx
+                .sess
                 .create_err(errs::NameAlreadyUsedInParameterList { span, first_use_span, name }),
             ResolutionError::MethodNotMemberOfTrait(method, trait_, candidate) => {
-                self.session.create_err(errs::MethodNotMemberOfTrait {
+                self.tcx.sess.create_err(errs::MethodNotMemberOfTrait {
                     span,
                     method,
                     trait_,
@@ -617,7 +620,7 @@ impl<'a> Resolver<'a> {
                 })
             }
             ResolutionError::TypeNotMemberOfTrait(type_, trait_, candidate) => {
-                self.session.create_err(errs::TypeNotMemberOfTrait {
+                self.tcx.sess.create_err(errs::TypeNotMemberOfTrait {
                     span,
                     type_,
                     trait_,
@@ -628,7 +631,7 @@ impl<'a> Resolver<'a> {
                 })
             }
             ResolutionError::ConstNotMemberOfTrait(const_, trait_, candidate) => {
-                self.session.create_err(errs::ConstNotMemberOfTrait {
+                self.tcx.sess.create_err(errs::ConstNotMemberOfTrait {
                     span,
                     const_,
                     trait_,
@@ -646,7 +649,7 @@ impl<'a> Resolver<'a> {
 
                 let msp = MultiSpan::from_spans(target_sp.clone());
                 let mut err = struct_span_err!(
-                    self.session,
+                    self.tcx.sess,
                     msp,
                     E0408,
                     "variable `{}` is not bound in all patterns",
@@ -684,8 +687,7 @@ impl<'a> Resolver<'a> {
                         err.span_help(span, &help_msg);
                     }
                     show_candidates(
-                        &self.session,
-                        &self.untracked.source_span,
+                        self.tcx,
                         &mut err,
                         Some(span),
                         &import_suggestions,
@@ -699,17 +701,19 @@ impl<'a> Resolver<'a> {
                 err
             }
             ResolutionError::VariableBoundWithDifferentMode(variable_name, first_binding_span) => {
-                self.session.create_err(errs::VariableBoundWithDifferentMode {
+                self.tcx.sess.create_err(errs::VariableBoundWithDifferentMode {
                     span,
                     first_binding_span,
                     variable_name,
                 })
             }
             ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => self
-                .session
+                .tcx
+                .sess
                 .create_err(errs::IdentifierBoundMoreThanOnceInParameterList { span, identifier }),
             ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => self
-                .session
+                .tcx
+                .sess
                 .create_err(errs::IdentifierBoundMoreThanOnceInSamePattern { span, identifier }),
             ResolutionError::UndeclaredLabel { name, suggestion } => {
                 let ((sub_reachable, sub_reachable_suggestion), sub_unreachable) = match suggestion
@@ -735,7 +739,7 @@ impl<'a> Resolver<'a> {
                     // No similarly-named labels exist.
                     None => ((None, None), None),
                 };
-                self.session.create_err(errs::UndeclaredLabel {
+                self.tcx.sess.create_err(errs::UndeclaredLabel {
                     span,
                     name,
                     sub_reachable,
@@ -760,21 +764,22 @@ impl<'a> Resolver<'a> {
                     };
                     (Some(suggestion), Some(mpart_suggestion))
                 };
-                self.session.create_err(errs::SelfImportsOnlyAllowedWithin {
+                self.tcx.sess.create_err(errs::SelfImportsOnlyAllowedWithin {
                     span,
                     suggestion,
                     mpart_suggestion,
                 })
             }
             ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
-                self.session.create_err(errs::SelfImportCanOnlyAppearOnceInTheList { span })
-            }
-            ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
-                self.session.create_err(errs::SelfImportOnlyInImportListWithNonEmptyPrefix { span })
+                self.tcx.sess.create_err(errs::SelfImportCanOnlyAppearOnceInTheList { span })
             }
+            ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => self
+                .tcx
+                .sess
+                .create_err(errs::SelfImportOnlyInImportListWithNonEmptyPrefix { span }),
             ResolutionError::FailedToResolve { label, suggestion } => {
                 let mut err =
-                    struct_span_err!(self.session, span, E0433, "failed to resolve: {}", &label);
+                    struct_span_err!(self.tcx.sess, span, E0433, "failed to resolve: {}", &label);
                 err.span_label(span, label);
 
                 if let Some((suggestions, msg, applicability)) = suggestion {
@@ -788,7 +793,7 @@ impl<'a> Resolver<'a> {
                 err
             }
             ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
-                self.session.create_err(errs::CannotCaptureDynamicEnvironmentInFnItem { span })
+                self.tcx.sess.create_err(errs::CannotCaptureDynamicEnvironmentInFnItem { span })
             }
             ResolutionError::AttemptToUseNonConstantValueInConstant(ident, suggestion, current) => {
                 // let foo =...
@@ -800,12 +805,13 @@ impl<'a> Resolver<'a> {
                 // the further the two are apart, the higher the chance of the suggestion being wrong
 
                 let sp = self
-                    .session
+                    .tcx
+                    .sess
                     .source_map()
                     .span_extend_to_prev_str(ident.span, current, true, false);
 
                 let ((with, with_label), without) = match sp {
-                    Some(sp) if !self.session.source_map().is_multiline(sp) => {
+                    Some(sp) if !self.tcx.sess.source_map().is_multiline(sp) => {
                         let sp = sp.with_lo(BytePos(sp.lo().0 - (current.len() as u32)));
                         (
                         (Some(errs::AttemptToUseNonConstantValueInConstantWithSuggestion {
@@ -826,7 +832,7 @@ impl<'a> Resolver<'a> {
                     ),
                 };
 
-                self.session.create_err(errs::AttemptToUseNonConstantValueInConstant {
+                self.tcx.sess.create_err(errs::AttemptToUseNonConstantValueInConstant {
                     span,
                     with,
                     with_label,
@@ -840,7 +846,7 @@ impl<'a> Resolver<'a> {
                 article,
                 shadowed_binding,
                 shadowed_binding_span,
-            } => self.session.create_err(errs::BindingShadowsSomethingUnacceptable {
+            } => self.tcx.sess.create_err(errs::BindingShadowsSomethingUnacceptable {
                 span,
                 shadowing_binding,
                 shadowed_binding,
@@ -857,13 +863,13 @@ impl<'a> Resolver<'a> {
                 name,
             }),
             ResolutionError::ForwardDeclaredGenericParam => {
-                self.session.create_err(errs::ForwardDeclaredGenericParam { span })
+                self.tcx.sess.create_err(errs::ForwardDeclaredGenericParam { span })
             }
             ResolutionError::ParamInTyOfConstParam(name) => {
-                self.session.create_err(errs::ParamInTyOfConstParam { span, name })
+                self.tcx.sess.create_err(errs::ParamInTyOfConstParam { span, name })
             }
             ResolutionError::ParamInNonTrivialAnonConst { name, is_type } => {
-                self.session.create_err(errs::ParamInNonTrivialAnonConst {
+                self.tcx.sess.create_err(errs::ParamInNonTrivialAnonConst {
                     span,
                     name,
                     sub_is_type: if is_type {
@@ -872,13 +878,14 @@ impl<'a> Resolver<'a> {
                         errs::ParamInNonTrivialAnonConstIsType::NotAType { name }
                     },
                     help: self
-                        .session
+                        .tcx
+                        .sess
                         .is_nightly_build()
                         .then_some(errs::ParamInNonTrivialAnonConstHelp),
                 })
             }
             ResolutionError::SelfInGenericParamDefault => {
-                self.session.create_err(errs::SelfInGenericParamDefault { span })
+                self.tcx.sess.create_err(errs::SelfInGenericParamDefault { span })
             }
             ResolutionError::UnreachableLabel { name, definition_span, suggestion } => {
                 let ((sub_suggestion_label, sub_suggestion), sub_unreachable_label) =
@@ -906,7 +913,7 @@ impl<'a> Resolver<'a> {
                         // No similarly-named labels exist.
                         None => ((None, None), None),
                     };
-                self.session.create_err(errs::UnreachableLabel {
+                self.tcx.sess.create_err(errs::UnreachableLabel {
                     span,
                     name,
                     definition_span,
@@ -922,7 +929,7 @@ impl<'a> Resolver<'a> {
                 trait_item_span,
                 trait_path,
             } => {
-                let mut err = self.session.struct_span_err_with_code(
+                let mut err = self.tcx.sess.struct_span_err_with_code(
                     span,
                     &format!(
                         "item `{}` is an associated {}, which doesn't match its trait `{}`",
@@ -935,9 +942,12 @@ impl<'a> Resolver<'a> {
                 err
             }
             ResolutionError::TraitImplDuplicate { name, trait_item_span, old_span } => self
-                .session
+                .tcx
+                .sess
                 .create_err(errs::TraitImplDuplicate { span, name, trait_item_span, old_span }),
-            ResolutionError::InvalidAsmSym => self.session.create_err(errs::InvalidAsmSym { span }),
+            ResolutionError::InvalidAsmSym => {
+                self.tcx.sess.create_err(errs::InvalidAsmSym { span })
+            }
         }
     }
 
@@ -947,7 +957,7 @@ impl<'a> Resolver<'a> {
     ) -> ErrorGuaranteed {
         match vis_resolution_error {
             VisResolutionError::Relative2018(span, path) => {
-                self.session.create_err(errs::Relative2018 {
+                self.tcx.sess.create_err(errs::Relative2018 {
                     span,
                     path_span: path.span,
                     // intentionally converting to String, as the text would also be used as
@@ -956,18 +966,20 @@ impl<'a> Resolver<'a> {
                 })
             }
             VisResolutionError::AncestorOnly(span) => {
-                self.session.create_err(errs::AncestorOnly(span))
+                self.tcx.sess.create_err(errs::AncestorOnly(span))
             }
             VisResolutionError::FailedToResolve(span, label, suggestion) => {
                 self.into_struct_error(span, ResolutionError::FailedToResolve { label, suggestion })
             }
             VisResolutionError::ExpectedFound(span, path_str, res) => {
-                self.session.create_err(errs::ExpectedFound { span, res, path_str })
+                self.tcx.sess.create_err(errs::ExpectedFound { span, res, path_str })
             }
             VisResolutionError::Indeterminate(span) => {
-                self.session.create_err(errs::Indeterminate(span))
+                self.tcx.sess.create_err(errs::Indeterminate(span))
+            }
+            VisResolutionError::ModuleOnly(span) => {
+                self.tcx.sess.create_err(errs::ModuleOnly(span))
             }
-            VisResolutionError::ModuleOnly(span) => self.session.create_err(errs::ModuleOnly(span)),
         }
         .emit()
     }
@@ -1204,7 +1216,7 @@ impl<'a> Resolver<'a> {
                             // a note about editions
                             let note = if let Some(did) = did {
                                 let requires_note = !did.is_local()
-                                    && this.cstore().item_attrs_untracked(did, this.session).any(
+                                    && this.cstore().item_attrs_untracked(did, this.tcx.sess).any(
                                         |attr| {
                                             if attr.has_name(sym::rustc_diagnostic_item) {
                                                 [sym::TryInto, sym::TryFrom, sym::FromIterator]
@@ -1302,7 +1314,7 @@ impl<'a> Resolver<'a> {
                     // otherwise cause duplicate suggestions.
                     continue;
                 }
-                let crate_id = self.crate_loader().maybe_process_path_extern(ident.name);
+                let crate_id = self.crate_loader(|c| c.maybe_process_path_extern(ident.name));
                 if let Some(crate_id) = crate_id {
                     let crate_root = self.expect_module(crate_id.as_def_id());
                     suggestions.extend(self.lookup_import_candidates_from_module(
@@ -1339,8 +1351,7 @@ impl<'a> Resolver<'a> {
         let import_suggestions =
             self.lookup_import_candidates(ident, Namespace::MacroNS, parent_scope, is_expected);
         show_candidates(
-            &self.session,
-            &self.untracked.source_span,
+            self.tcx,
             err,
             None,
             &import_suggestions,
@@ -1364,7 +1375,7 @@ impl<'a> Resolver<'a> {
             && let ModuleKind::Def(DefKind::Enum, def_id, _) = parent_scope.module.kind
             && let Some(span) = self.opt_span(def_id)
         {
-            let source_map = self.session.source_map();
+            let source_map = self.tcx.sess.source_map();
             let head_span = source_map.guess_head_span(span);
             if let Ok(head) = source_map.span_to_snippet(head_span) {
                 err.span_suggestion(head_span, "consider adding a derive", format!("#[derive(Default)]\n{head}"), Applicability::MaybeIncorrect);
@@ -1441,7 +1452,7 @@ impl<'a> Resolver<'a> {
         };
         let def_span = suggestion.res.opt_def_id().and_then(|def_id| match def_id.krate {
             LOCAL_CRATE => self.opt_span(def_id),
-            _ => Some(self.cstore().get_span_untracked(def_id, self.session)),
+            _ => Some(self.cstore().get_span_untracked(def_id, self.tcx.sess)),
         });
         if let Some(def_span) = def_span {
             if span.overlaps(def_span) {
@@ -1471,7 +1482,7 @@ impl<'a> Resolver<'a> {
             };
 
             err.span_label(
-                self.session.source_map().guess_head_span(def_span),
+                self.tcx.sess.source_map().guess_head_span(def_span),
                 &format!(
                     "{}{} `{}` defined here",
                     prefix,
@@ -1496,7 +1507,7 @@ impl<'a> Resolver<'a> {
 
     fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
         let res = b.res();
-        if b.span.is_dummy() || !self.session.source_map().is_span_accessible(b.span) {
+        if b.span.is_dummy() || !self.tcx.sess.source_map().is_span_accessible(b.span) {
             // These already contain the "built-in" prefix or look bad with it.
             let add_built_in =
                 !matches!(b.res(), Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod);
@@ -1504,7 +1515,7 @@ impl<'a> Resolver<'a> {
                 ("", " from prelude")
             } else if b.is_extern_crate()
                 && !b.is_import()
-                && self.session.opts.externs.get(ident.as_str()).is_some()
+                && self.tcx.sess.opts.externs.get(ident.as_str()).is_some()
             {
                 ("", " passed with `--extern`")
             } else if add_built_in {
@@ -1530,7 +1541,7 @@ impl<'a> Resolver<'a> {
             (b1, b2, misc1, misc2, false)
         };
 
-        let mut err = struct_span_err!(self.session, ident.span, E0659, "`{ident}` is ambiguous");
+        let mut err = struct_span_err!(self.tcx.sess, ident.span, E0659, "`{ident}` is ambiguous");
         err.span_label(ident.span, "ambiguous name");
         err.note(&format!("ambiguous because of {}", kind.descr()));
 
@@ -1552,12 +1563,12 @@ impl<'a> Resolver<'a> {
             if b.is_extern_crate() && ident.span.rust_2018() {
                 help_msgs.push(format!("use `::{ident}` to refer to this {thing} unambiguously"))
             }
-            if misc == AmbiguityErrorMisc::SuggestCrate {
-                help_msgs
-                    .push(format!("use `crate::{ident}` to refer to this {thing} unambiguously"))
-            } else if misc == AmbiguityErrorMisc::SuggestSelf {
-                help_msgs
-                    .push(format!("use `self::{ident}` to refer to this {thing} unambiguously"))
+            match misc {
+                AmbiguityErrorMisc::SuggestCrate => help_msgs
+                    .push(format!("use `crate::{ident}` to refer to this {thing} unambiguously")),
+                AmbiguityErrorMisc::SuggestSelf => help_msgs
+                    .push(format!("use `self::{ident}` to refer to this {thing} unambiguously")),
+                AmbiguityErrorMisc::FromPrelude | AmbiguityErrorMisc::None => {}
             }
 
             err.span_note(b.span, &note_msg);
@@ -1602,7 +1613,7 @@ impl<'a> Resolver<'a> {
         // Print the primary message.
         let descr = get_descr(binding);
         let mut err =
-            struct_span_err!(self.session, ident.span, E0603, "{} `{}` is private", descr, ident);
+            struct_span_err!(self.tcx.sess, ident.span, E0603, "{} `{}` is private", descr, ident);
         err.span_label(ident.span, &format!("private {}", descr));
         if let Some(span) = ctor_fields_span {
             err.span_label(span, "a constructor is private if any of the fields is private");
@@ -1648,7 +1659,7 @@ impl<'a> Resolver<'a> {
                 which = if first { "" } else { " which" },
                 dots = if next_binding.is_some() { "..." } else { "" },
             );
-            let def_span = self.session.source_map().guess_head_span(binding.span);
+            let def_span = self.tcx.sess.source_map().guess_head_span(binding.span);
             let mut note_span = MultiSpan::from_span(def_span);
             if !first && binding.vis.is_public() {
                 note_span.push_span_label(def_span, "consider importing it directly");
@@ -1717,7 +1728,7 @@ impl<'a> Resolver<'a> {
                         Applicability::MaybeIncorrect,
                     )),
                 )
-            } else if self.session.edition() == Edition::Edition2015 {
+            } else if self.tcx.sess.is_rust_2015() {
                 (
                     format!("maybe a missing crate `{ident}`?"),
                     Some((
@@ -1736,7 +1747,7 @@ impl<'a> Resolver<'a> {
             let parent = match parent {
                 // ::foo is mounted at the crate root for 2015, and is the extern
                 // prelude for 2018+
-                kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
+                kw::PathRoot if self.tcx.sess.edition() > Edition::Edition2015 => {
                     "the list of imported crates".to_owned()
                 }
                 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
@@ -1795,6 +1806,8 @@ impl<'a> Resolver<'a> {
                         found("module")
                     } else {
                         match binding.res() {
+                            // Avoid using TyCtxt::def_kind_descr in the resolver, because it
+                            // indirectly *calls* the resolver, and would cause a query cycle.
                             Res::Def(kind, id) => found(kind.descr(id)),
                             _ => found(ns_to_try.descr()),
                         }
@@ -1879,15 +1892,13 @@ impl<'a> Resolver<'a> {
             (format!("use of undeclared crate or module `{}`", ident), suggestion)
         }
     }
-}
 
-impl<'a, 'b> ImportResolver<'a, 'b> {
     /// Adds suggestions for a path that cannot be resolved.
     pub(crate) fn make_path_suggestion(
         &mut self,
         span: Span,
         mut path: Vec<Segment>,
-        parent_scope: &ParentScope<'b>,
+        parent_scope: &ParentScope<'a>,
     ) -> Option<(Vec<Segment>, Option<String>)> {
         debug!("make_path_suggestion: span={:?} path={:?}", span, path);
 
@@ -1922,11 +1933,11 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
     fn make_missing_self_suggestion(
         &mut self,
         mut path: Vec<Segment>,
-        parent_scope: &ParentScope<'b>,
+        parent_scope: &ParentScope<'a>,
     ) -> Option<(Vec<Segment>, Option<String>)> {
         // Replace first ident with `self` and check if that is valid.
         path[0].ident.name = kw::SelfLower;
-        let result = self.r.maybe_resolve_path(&path, None, parent_scope);
+        let result = self.maybe_resolve_path(&path, None, parent_scope);
         debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
         if let PathResult::Module(..) = result { Some((path, None)) } else { None }
     }
@@ -1941,11 +1952,11 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
     fn make_missing_crate_suggestion(
         &mut self,
         mut path: Vec<Segment>,
-        parent_scope: &ParentScope<'b>,
+        parent_scope: &ParentScope<'a>,
     ) -> Option<(Vec<Segment>, Option<String>)> {
         // Replace first ident with `crate` and check if that is valid.
         path[0].ident.name = kw::Crate;
-        let result = self.r.maybe_resolve_path(&path, None, parent_scope);
+        let result = self.maybe_resolve_path(&path, None, parent_scope);
         debug!("make_missing_crate_suggestion:  path={:?} result={:?}", path, result);
         if let PathResult::Module(..) = result {
             Some((
@@ -1972,11 +1983,11 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
     fn make_missing_super_suggestion(
         &mut self,
         mut path: Vec<Segment>,
-        parent_scope: &ParentScope<'b>,
+        parent_scope: &ParentScope<'a>,
     ) -> Option<(Vec<Segment>, Option<String>)> {
         // Replace first ident with `crate` and check if that is valid.
         path[0].ident.name = kw::Super;
-        let result = self.r.maybe_resolve_path(&path, None, parent_scope);
+        let result = self.maybe_resolve_path(&path, None, parent_scope);
         debug!("make_missing_super_suggestion:  path={:?} result={:?}", path, result);
         if let PathResult::Module(..) = result { Some((path, None)) } else { None }
     }
@@ -1994,9 +2005,9 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
     fn make_external_crate_suggestion(
         &mut self,
         mut path: Vec<Segment>,
-        parent_scope: &ParentScope<'b>,
+        parent_scope: &ParentScope<'a>,
     ) -> Option<(Vec<Segment>, Option<String>)> {
-        if path[1].ident.span.rust_2015() {
+        if path[1].ident.span.is_rust_2015() {
             return None;
         }
 
@@ -2004,13 +2015,13 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         // 1) some consistent ordering for emitted diagnostics, and
         // 2) `std` suggestions before `core` suggestions.
         let mut extern_crate_names =
-            self.r.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>();
+            self.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>();
         extern_crate_names.sort_by(|a, b| b.as_str().partial_cmp(a.as_str()).unwrap());
 
         for name in extern_crate_names.into_iter() {
             // Replace first ident with a crate name and check if that is valid.
             path[0].ident.name = name;
-            let result = self.r.maybe_resolve_path(&path, None, parent_scope);
+            let result = self.maybe_resolve_path(&path, None, parent_scope);
             debug!(
                 "make_external_crate_suggestion: name={:?} path={:?} result={:?}",
                 name, path, result
@@ -2037,8 +2048,8 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
     /// ```
     pub(crate) fn check_for_module_export_macro(
         &mut self,
-        import: &'b Import<'b>,
-        module: ModuleOrUniformRoot<'b>,
+        import: &'a Import<'a>,
+        module: ModuleOrUniformRoot<'a>,
         ident: Ident,
     ) -> Option<(Option<Suggestion>, Option<String>)> {
         let ModuleOrUniformRoot::Module(mut crate_module) = module else {
@@ -2055,8 +2066,8 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             return None;
         }
 
-        let resolutions = self.r.resolutions(crate_module).borrow();
-        let resolution = resolutions.get(&self.r.new_key(ident, MacroNS))?;
+        let resolutions = self.resolutions(crate_module).borrow();
+        let resolution = resolutions.get(&self.new_key(ident, MacroNS))?;
         let binding = resolution.borrow().binding()?;
         if let Res::Def(DefKind::Macro(MacroKind::Bang), _) = binding.res() {
             let module_name = crate_module.kind.name().unwrap();
@@ -2077,7 +2088,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                 //   ie. `use a::b::{c, d, e};`
                 //                      ^^^
                 let (found_closing_brace, binding_span) = find_span_of_binding_until_next_binding(
-                    self.r.session,
+                    self.tcx.sess,
                     import.span,
                     import.use_span,
                 );
@@ -2096,7 +2107,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     //   ie. `use a::b::{c, d};`
                     //                    ^^^
                     if let Some(previous_span) =
-                        extend_span_to_previous_binding(self.r.session, binding_span)
+                        extend_span_to_previous_binding(self.tcx.sess, binding_span)
                     {
                         debug!("check_for_module_export_macro: previous_span={:?}", previous_span);
                         removal_span = removal_span.with_lo(previous_span.lo());
@@ -2114,7 +2125,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                 //   or  `use a::{b, c, d}};`
                 //               ^^^^^^^^^^^
                 let (has_nested, after_crate_name) = find_span_immediately_after_crate_name(
-                    self.r.session,
+                    self.tcx.sess,
                     module_name,
                     import.use_span,
                 );
@@ -2123,7 +2134,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     has_nested, after_crate_name
                 );
 
-                let source_map = self.r.session.source_map();
+                let source_map = self.tcx.sess.source_map();
 
                 // Make sure this is actually crate-relative.
                 let is_definitely_crate = import
@@ -2345,8 +2356,7 @@ pub(crate) enum DiagnosticMode {
 }
 
 pub(crate) fn import_candidates(
-    session: &Session,
-    source_span: &IndexVec<LocalDefId, Span>,
+    tcx: TyCtxt<'_>,
     err: &mut Diagnostic,
     // This is `None` if all placement locations are inside expansions
     use_placement_span: Option<Span>,
@@ -2355,8 +2365,7 @@ pub(crate) fn import_candidates(
     append: &str,
 ) {
     show_candidates(
-        session,
-        source_span,
+        tcx,
         err,
         use_placement_span,
         candidates,
@@ -2372,8 +2381,7 @@ pub(crate) fn import_candidates(
 /// entities with that name in all crates. This method allows outputting the
 /// results of this search in a programmer-friendly way
 fn show_candidates(
-    session: &Session,
-    source_span: &IndexVec<LocalDefId, Span>,
+    tcx: TyCtxt<'_>,
     err: &mut Diagnostic,
     // This is `None` if all placement locations are inside expansions
     use_placement_span: Option<Span>,
@@ -2498,8 +2506,8 @@ fn show_candidates(
             );
 
             if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
-                let span = source_span[local_def_id];
-                let span = session.source_map().guess_head_span(span);
+                let span = tcx.source_span(local_def_id);
+                let span = tcx.sess.source_map().guess_head_span(span);
                 let mut multi_span = MultiSpan::from_span(span);
                 multi_span.push_span_label(span, "not accessible");
                 err.span_note(multi_span, &msg);
@@ -2529,8 +2537,8 @@ fn show_candidates(
             let mut spans = Vec::new();
             for (name, _, def_id, _) in &inaccessible_path_strings {
                 if let Some(local_def_id) = def_id.and_then(|did| did.as_local()) {
-                    let span = source_span[local_def_id];
-                    let span = session.source_map().guess_head_span(span);
+                    let span = tcx.source_span(local_def_id);
+                    let span = tcx.sess.source_map().guess_head_span(span);
                     spans.push((name, span));
                 } else {
                     if !has_colon {
diff --git a/compiler/rustc_resolve/src/effective_visibilities.rs b/compiler/rustc_resolve/src/effective_visibilities.rs
index b8efa3f8b..7bd90d7e3 100644
--- a/compiler/rustc_resolve/src/effective_visibilities.rs
+++ b/compiler/rustc_resolve/src/effective_visibilities.rs
@@ -1,4 +1,4 @@
-use crate::{NameBinding, NameBindingKind, Resolver, ResolverTree};
+use crate::{NameBinding, NameBindingKind, Resolver};
 use rustc_ast::ast;
 use rustc_ast::visit;
 use rustc_ast::visit::Visitor;
@@ -7,8 +7,8 @@ use rustc_ast::EnumDef;
 use rustc_data_structures::intern::Interned;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::def_id::CRATE_DEF_ID;
+use rustc_middle::middle::privacy::Level;
 use rustc_middle::middle::privacy::{EffectiveVisibilities, EffectiveVisibility};
-use rustc_middle::middle::privacy::{IntoDefIdTree, Level};
 use rustc_middle::ty::{DefIdTree, Visibility};
 use std::mem;
 
@@ -29,8 +29,8 @@ impl ParentId<'_> {
     }
 }
 
-pub struct EffectiveVisibilitiesVisitor<'r, 'a> {
-    r: &'r mut Resolver<'a>,
+pub(crate) struct EffectiveVisibilitiesVisitor<'r, 'a, 'tcx> {
+    r: &'r mut Resolver<'a, 'tcx>,
     def_effective_visibilities: EffectiveVisibilities,
     /// While walking import chains we need to track effective visibilities per-binding, and def id
     /// keys in `Resolver::effective_visibilities` are not enough for that, because multiple
@@ -41,7 +41,7 @@ pub struct EffectiveVisibilitiesVisitor<'r, 'a> {
     changed: bool,
 }
 
-impl Resolver<'_> {
+impl Resolver<'_, '_> {
     fn nearest_normal_mod(&mut self, def_id: LocalDefId) -> LocalDefId {
         self.get_nearest_non_block_module(def_id.to_def_id()).nearest_parent_mod().expect_local()
     }
@@ -67,18 +67,14 @@ impl Resolver<'_> {
     }
 }
 
-impl<'a, 'b> IntoDefIdTree for &'b mut Resolver<'a> {
-    type Tree = &'b Resolver<'a>;
-    fn tree(self) -> Self::Tree {
-        self
-    }
-}
-
-impl<'r, 'a> EffectiveVisibilitiesVisitor<'r, 'a> {
+impl<'r, 'a, 'tcx> EffectiveVisibilitiesVisitor<'r, 'a, 'tcx> {
     /// Fills the `Resolver::effective_visibilities` table with public & exported items
     /// For now, this doesn't resolve macros (FIXME) and cannot resolve Impl, as we
     /// need access to a TyCtxt for that.
-    pub fn compute_effective_visibilities<'c>(r: &'r mut Resolver<'a>, krate: &'c Crate) {
+    pub(crate) fn compute_effective_visibilities<'c>(
+        r: &'r mut Resolver<'a, 'tcx>,
+        krate: &'c Crate,
+    ) {
         let mut visitor = EffectiveVisibilitiesVisitor {
             r,
             def_effective_visibilities: Default::default(),
@@ -104,11 +100,7 @@ impl<'r, 'a> EffectiveVisibilitiesVisitor<'r, 'a> {
         for (binding, eff_vis) in visitor.import_effective_visibilities.iter() {
             let NameBindingKind::Import { import, .. } = binding.kind else { unreachable!() };
             if let Some(node_id) = import.id() {
-                r.effective_visibilities.update_eff_vis(
-                    r.local_def_id(node_id),
-                    eff_vis,
-                    ResolverTree(&r.untracked),
-                )
+                r.effective_visibilities.update_eff_vis(r.local_def_id(node_id), eff_vis, r.tcx)
             }
         }
 
@@ -164,26 +156,28 @@ impl<'r, 'a> EffectiveVisibilitiesVisitor<'r, 'a> {
         let nominal_vis = binding.vis.expect_local();
         let private_vis = self.cheap_private_vis(parent_id);
         let inherited_eff_vis = self.effective_vis_or_private(parent_id);
+        let tcx = self.r.tcx;
         self.changed |= self.import_effective_visibilities.update(
             binding,
             nominal_vis,
-            |r| (private_vis.unwrap_or_else(|| r.private_vis_import(binding)), r),
+            || private_vis.unwrap_or_else(|| self.r.private_vis_import(binding)),
             inherited_eff_vis,
             parent_id.level(),
-            &mut *self.r,
+            tcx,
         );
     }
 
     fn update_def(&mut self, def_id: LocalDefId, nominal_vis: Visibility, parent_id: ParentId<'a>) {
         let private_vis = self.cheap_private_vis(parent_id);
         let inherited_eff_vis = self.effective_vis_or_private(parent_id);
+        let tcx = self.r.tcx;
         self.changed |= self.def_effective_visibilities.update(
             def_id,
             nominal_vis,
-            |r| (private_vis.unwrap_or_else(|| r.private_vis_def(def_id)), r),
+            || private_vis.unwrap_or_else(|| self.r.private_vis_def(def_id)),
             inherited_eff_vis,
             parent_id.level(),
-            &mut *self.r,
+            tcx,
         );
     }
 
@@ -192,7 +186,7 @@ impl<'r, 'a> EffectiveVisibilitiesVisitor<'r, 'a> {
     }
 }
 
-impl<'r, 'ast> Visitor<'ast> for EffectiveVisibilitiesVisitor<'ast, 'r> {
+impl<'r, 'ast, 'tcx> Visitor<'ast> for EffectiveVisibilitiesVisitor<'ast, 'r, 'tcx> {
     fn visit_item(&mut self, item: &'ast ast::Item) {
         let def_id = self.r.local_def_id(item.id);
         // Update effective visibilities of nested items.
diff --git a/compiler/rustc_resolve/src/errors.rs b/compiler/rustc_resolve/src/errors.rs
index 2c4427746..867363f42 100644
--- a/compiler/rustc_resolve/src/errors.rs
+++ b/compiler/rustc_resolve/src/errors.rs
@@ -38,7 +38,7 @@ pub(crate) struct NameAlreadyUsedInParameterList {
     #[primary_span]
     #[label]
     pub(crate) span: Span,
-    #[label(first_use_of_name)]
+    #[label(resolve_first_use_of_name)]
     pub(crate) first_use_span: Span,
     pub(crate) name: Symbol,
 }
@@ -121,7 +121,7 @@ pub(crate) struct VariableBoundWithDifferentMode {
     #[primary_span]
     #[label]
     pub(crate) span: Span,
-    #[label(first_binding_span)]
+    #[label(resolve_first_binding_span)]
     pub(crate) first_binding_span: Span,
     pub(crate) variable_name: Symbol,
 }
@@ -293,7 +293,7 @@ pub(crate) struct BindingShadowsSomethingUnacceptable<'a> {
     pub(crate) article: &'a str,
     #[subdiagnostic]
     pub(crate) sub_suggestion: Option<BindingShadowsSomethingUnacceptableSuggestion>,
-    #[label(label_shadowed_binding)]
+    #[label(resolve_label_shadowed_binding)]
     pub(crate) shadowed_binding_span: Span,
     pub(crate) participle: &'a str,
     pub(crate) name: Symbol,
@@ -369,7 +369,7 @@ pub(crate) struct UnreachableLabel {
     #[label]
     pub(crate) span: Span,
     pub(crate) name: Symbol,
-    #[label(label_definition_span)]
+    #[label(resolve_label_definition_span)]
     pub(crate) definition_span: Span,
     #[subdiagnostic]
     pub(crate) sub_suggestion: Option<UnreachableLabelSubSuggestion>,
@@ -413,7 +413,7 @@ pub(crate) struct TraitImplMismatch {
     pub(crate) span: Span,
     pub(crate) name: Symbol,
     pub(crate) kind: String,
-    #[label(label_trait_item)]
+    #[label(resolve_label_trait_item)]
     pub(crate) trait_item_span: Span,
     pub(crate) trait_path: String,
     pub(crate) code: String,
@@ -434,9 +434,9 @@ pub(crate) struct TraitImplDuplicate {
     #[primary_span]
     #[label]
     pub(crate) span: Span,
-    #[label(old_span_label)]
+    #[label(resolve_old_span_label)]
     pub(crate) old_span: Span,
-    #[label(trait_item_span)]
+    #[label(resolve_trait_item_span)]
     pub(crate) trait_item_span: Span,
     pub(crate) name: Symbol,
 }
diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
index a84652a31..52f0b65fa 100644
--- a/compiler/rustc_resolve/src/ident.rs
+++ b/compiler/rustc_resolve/src/ident.rs
@@ -7,7 +7,6 @@ use rustc_middle::ty;
 use rustc_session::lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK;
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_span::def_id::LocalDefId;
-use rustc_span::edition::Edition;
 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext};
 use rustc_span::symbol::{kw, Ident};
 use rustc_span::{Span, DUMMY_SP};
@@ -29,7 +28,7 @@ use RibKind::*;
 
 type Visibility = ty::Visibility<LocalDefId>;
 
-impl<'a> Resolver<'a> {
+impl<'a, 'tcx> Resolver<'a, 'tcx> {
     /// A generic scope visitor.
     /// Visits scopes in order to resolve some identifier in them or perform other actions.
     /// If the callback returns `Some` result, we stop visiting scopes and return it.
@@ -86,7 +85,7 @@ impl<'a> Resolver<'a> {
         // 4c. Standard library prelude (de-facto closed, controlled).
         // 6. Language prelude: builtin attributes (closed, controlled).
 
-        let rust_2015 = ctxt.edition() == Edition::Edition2015;
+        let rust_2015 = ctxt.edition().is_rust_2015();
         let (ns, macro_kind, is_absolute_path) = match scope_set {
             ScopeSet::All(ns, _) => (ns, None, false),
             ScopeSet::AbsolutePath(ns) => (ns, None, true),
@@ -369,7 +368,7 @@ impl<'a> Resolver<'a> {
     /// This is a variation of `fn resolve_ident_in_lexical_scope` that can be run during
     /// expansion and import resolution (perhaps they can be merged in the future).
     /// The function is used for resolving initial segments of macro paths (e.g., `foo` in
-    /// `foo::bar!(); or `foo!();`) and also for import paths on 2018 edition.
+    /// `foo::bar!();` or `foo!();`) and also for import paths on 2018 edition.
     #[instrument(level = "debug", skip(self, scope_set))]
     pub(crate) fn early_resolve_ident_in_lexical_scope(
         &mut self,
@@ -1180,7 +1179,7 @@ impl<'a> Resolver<'a> {
                         }
 
                         ConstantItemRibKind(trivial, _) => {
-                            let features = self.session.features_untracked();
+                            let features = self.tcx.sess.features_untracked();
                             // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
                             if !(trivial == ConstantHasGenerics::Yes
                                 || features.generic_const_exprs)
@@ -1209,7 +1208,7 @@ impl<'a> Resolver<'a> {
                                                 is_type: true,
                                             },
                                         );
-                                        self.session.delay_span_bug(span, CG_BUG_STR);
+                                        self.tcx.sess.delay_span_bug(span, CG_BUG_STR);
                                     }
 
                                     return Res::Err;
@@ -1256,7 +1255,7 @@ impl<'a> Resolver<'a> {
                         | ForwardGenericParamBanRibKind => continue,
 
                         ConstantItemRibKind(trivial, _) => {
-                            let features = self.session.features_untracked();
+                            let features = self.tcx.sess.features_untracked();
                             // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
                             if !(trivial == ConstantHasGenerics::Yes
                                 || features.generic_const_exprs)
@@ -1269,7 +1268,7 @@ impl<'a> Resolver<'a> {
                                             is_type: false,
                                         },
                                     );
-                                    self.session.delay_span_bug(span, CG_BUG_STR);
+                                    self.tcx.sess.delay_span_bug(span, CG_BUG_STR);
                                 }
 
                                 return Res::Err;
@@ -1398,7 +1397,10 @@ impl<'a> Resolver<'a> {
                         module = Some(ModuleOrUniformRoot::ExternPrelude);
                         continue;
                     }
-                    if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
+                    if name == kw::PathRoot
+                        && ident.span.is_rust_2015()
+                        && self.tcx.sess.rust_2018()
+                    {
                         // `::a::b` from 2015 macro on 2018 global edition
                         module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
                         continue;
@@ -1494,7 +1496,8 @@ impl<'a> Resolver<'a> {
                         record_segment_res(self, res);
                     } else if res == Res::ToolMod && i + 1 != path.len() {
                         if binding.is_import() {
-                            self.session
+                            self.tcx
+                                .sess
                                 .struct_span_err(
                                     ident.span,
                                     "cannot use a tool module through an import",
diff --git a/compiler/rustc_resolve/src/imports.rs b/compiler/rustc_resolve/src/imports.rs
index 00f65ac37..4dab0836d 100644
--- a/compiler/rustc_resolve/src/imports.rs
+++ b/compiler/rustc_resolve/src/imports.rs
@@ -21,8 +21,8 @@ use rustc_middle::span_bug;
 use rustc_middle::ty;
 use rustc_session::lint::builtin::{PUB_USE_OF_PRIVATE_EXTERN_CRATE, UNUSED_IMPORTS};
 use rustc_session::lint::BuiltinLintDiagnostics;
+use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::hygiene::LocalExpnId;
-use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::symbol::{kw, Ident, Symbol};
 use rustc_span::Span;
 
@@ -33,7 +33,7 @@ type Res = def::Res<NodeId>;
 
 /// Contains data for specific kinds of imports.
 #[derive(Clone)]
-pub enum ImportKind<'a> {
+pub(crate) enum ImportKind<'a> {
     Single {
         /// `source` in `use prefix::source as target`.
         source: Ident,
@@ -157,11 +157,11 @@ pub(crate) struct Import<'a> {
 }
 
 impl<'a> Import<'a> {
-    pub fn is_glob(&self) -> bool {
+    pub(crate) fn is_glob(&self) -> bool {
         matches!(self.kind, ImportKind::Glob { .. })
     }
 
-    pub fn is_nested(&self) -> bool {
+    pub(crate) fn is_nested(&self) -> bool {
         match self.kind {
             ImportKind::Single { nested, .. } => nested,
             _ => false,
@@ -210,6 +210,17 @@ impl<'a> NameResolution<'a> {
     }
 }
 
+/// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved
+/// import errors within the same use tree into a single diagnostic.
+#[derive(Debug, Clone)]
+struct UnresolvedImportError {
+    span: Span,
+    label: Option<String>,
+    note: Option<String>,
+    suggestion: Option<Suggestion>,
+    candidates: Option<Vec<ImportSuggestion>>,
+}
+
 // Reexports of the form `pub use foo as bar;` where `foo` is `extern crate foo;`
 // are permitted for backward-compatibility under a deprecation lint.
 fn pub_use_of_private_extern_crate_hack(import: &Import<'_>, binding: &NameBinding<'_>) -> bool {
@@ -225,7 +236,7 @@ fn pub_use_of_private_extern_crate_hack(import: &Import<'_>, binding: &NameBindi
     }
 }
 
-impl<'a> Resolver<'a> {
+impl<'a, 'tcx> Resolver<'a, 'tcx> {
     /// Given a binding and an import that resolves to it,
     /// return the corresponding binding defined by the import.
     pub(crate) fn import(
@@ -333,7 +344,7 @@ impl<'a> Resolver<'a> {
     // If the resolution becomes a success, define it in the module's glob importers.
     fn update_resolution<T, F>(&mut self, module: Module<'a>, key: BindingKey, f: F) -> T
     where
-        F: FnOnce(&mut Resolver<'a>, &mut NameResolution<'a>) -> T,
+        F: FnOnce(&mut Resolver<'a, 'tcx>, &mut NameResolution<'a>) -> T,
     {
         // Ensure that `resolution` isn't borrowed when defining in the module's glob importers,
         // during which the resolution might end up getting re-defined via a glob cycle.
@@ -392,24 +403,7 @@ impl<'a> Resolver<'a> {
             }
         }
     }
-}
-
-/// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved
-/// import errors within the same use tree into a single diagnostic.
-#[derive(Debug, Clone)]
-struct UnresolvedImportError {
-    span: Span,
-    label: Option<String>,
-    note: Option<String>,
-    suggestion: Option<Suggestion>,
-    candidates: Option<Vec<ImportSuggestion>>,
-}
-
-pub struct ImportResolver<'a, 'b> {
-    pub r: &'a mut Resolver<'b>,
-}
 
-impl<'a, 'b> ImportResolver<'a, 'b> {
     // Import resolution
     //
     // This is a fixed-point algorithm. We resolve imports until our efforts
@@ -420,29 +414,29 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
     /// Resolves all imports for the crate. This method performs the fixed-
     /// point iteration.
-    pub fn resolve_imports(&mut self) {
-        let mut prev_num_indeterminates = self.r.indeterminate_imports.len() + 1;
-        while self.r.indeterminate_imports.len() < prev_num_indeterminates {
-            prev_num_indeterminates = self.r.indeterminate_imports.len();
-            for import in mem::take(&mut self.r.indeterminate_imports) {
+    pub(crate) fn resolve_imports(&mut self) {
+        let mut prev_num_indeterminates = self.indeterminate_imports.len() + 1;
+        while self.indeterminate_imports.len() < prev_num_indeterminates {
+            prev_num_indeterminates = self.indeterminate_imports.len();
+            for import in mem::take(&mut self.indeterminate_imports) {
                 match self.resolve_import(&import) {
-                    true => self.r.determined_imports.push(import),
-                    false => self.r.indeterminate_imports.push(import),
+                    true => self.determined_imports.push(import),
+                    false => self.indeterminate_imports.push(import),
                 }
             }
         }
     }
 
-    pub fn finalize_imports(&mut self) {
-        for module in self.r.arenas.local_modules().iter() {
+    pub(crate) fn finalize_imports(&mut self) {
+        for module in self.arenas.local_modules().iter() {
             self.finalize_resolutions_in(module);
         }
 
         let mut seen_spans = FxHashSet::default();
         let mut errors = vec![];
         let mut prev_root_id: NodeId = NodeId::from_u32(0);
-        let determined_imports = mem::take(&mut self.r.determined_imports);
-        let indeterminate_imports = mem::take(&mut self.r.indeterminate_imports);
+        let determined_imports = mem::take(&mut self.determined_imports);
+        let indeterminate_imports = mem::take(&mut self.indeterminate_imports);
 
         for (is_indeterminate, import) in determined_imports
             .into_iter()
@@ -453,7 +447,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
             // If this import is unresolved then create a dummy import
             // resolution for it so that later resolve stages won't complain.
-            self.r.import_dummy_binding(import);
+            self.import_dummy_binding(import);
 
             if let Some(err) = unresolved_import_error {
                 if let ImportKind::Single { source, ref source_bindings, .. } = import.kind {
@@ -526,7 +520,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             .collect::<Vec<_>>();
         let msg = format!("unresolved import{} {}", pluralize!(paths.len()), paths.join(", "),);
 
-        let mut diag = struct_span_err!(self.r.session, span, E0432, "{}", &msg);
+        let mut diag = struct_span_err!(self.tcx.sess, span, E0432, "{}", &msg);
 
         if let Some((_, UnresolvedImportError { note: Some(note), .. })) = errors.iter().last() {
             diag.note(note);
@@ -548,8 +542,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             if let Some(candidates) = &err.candidates {
                 match &import.kind {
                     ImportKind::Single { nested: false, source, target, .. } => import_candidates(
-                        self.r.session,
-                        &self.r.untracked.source_span,
+                        self.tcx,
                         &mut diag,
                         Some(err.span),
                         &candidates,
@@ -561,8 +554,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     ),
                     ImportKind::Single { nested: true, source, target, .. } => {
                         import_candidates(
-                            self.r.session,
-                            &self.r.untracked.source_span,
+                            self.tcx,
                             &mut diag,
                             None,
                             &candidates,
@@ -583,7 +575,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
     /// Attempts to resolve the given import, returning true if its resolution is determined.
     /// If successful, the resolved bindings are written into the module.
-    fn resolve_import(&mut self, import: &'b Import<'b>) -> bool {
+    fn resolve_import(&mut self, import: &'a Import<'a>) -> bool {
         debug!(
             "(resolving import for module) resolving import `{}::...` in `{}`",
             Segment::names_to_string(&import.module_path),
@@ -596,8 +588,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             // For better failure detection, pretend that the import will
             // not define any names while resolving its module path.
             let orig_vis = import.vis.take();
-            let path_res =
-                self.r.maybe_resolve_path(&import.module_path, None, &import.parent_scope);
+            let path_res = self.maybe_resolve_path(&import.module_path, None, &import.parent_scope);
             import.vis.set(orig_vis);
 
             match path_res {
@@ -625,7 +616,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         };
 
         let mut indeterminate = false;
-        self.r.per_ns(|this, ns| {
+        self.per_ns(|this, ns| {
             if !type_ns_only || ns == TypeNS {
                 if let Err(Undetermined) = source_bindings[ns].get() {
                     // For better failure detection, pretend that the import will
@@ -658,7 +649,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     source_binding @ (Ok(..) | Err(Determined)) => {
                         if source_binding.is_ok() {
                             let msg = format!("`{}` is not directly importable", target);
-                            struct_span_err!(this.session, import.span, E0253, "{}", &msg)
+                            struct_span_err!(this.tcx.sess, import.span, E0253, "{}", &msg)
                                 .span_label(import.span, "cannot be imported directly")
                                 .emit();
                         }
@@ -678,15 +669,15 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
     ///
     /// Optionally returns an unresolved import error. This error is buffered and used to
     /// consolidate multiple unresolved import errors into a single diagnostic.
-    fn finalize_import(&mut self, import: &'b Import<'b>) -> Option<UnresolvedImportError> {
+    fn finalize_import(&mut self, import: &'a Import<'a>) -> Option<UnresolvedImportError> {
         let orig_vis = import.vis.take();
         let ignore_binding = match &import.kind {
             ImportKind::Single { target_bindings, .. } => target_bindings[TypeNS].get(),
             _ => None,
         };
-        let prev_ambiguity_errors_len = self.r.ambiguity_errors.len();
+        let prev_ambiguity_errors_len = self.ambiguity_errors.len();
         let finalize = Finalize::with_root_span(import.root_id, import.span, import.root_span);
-        let path_res = self.r.resolve_path(
+        let path_res = self.resolve_path(
             &import.module_path,
             None,
             &import.parent_scope,
@@ -694,7 +685,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             ignore_binding,
         );
 
-        let no_ambiguity = self.r.ambiguity_errors.len() == prev_ambiguity_errors_len;
+        let no_ambiguity = self.ambiguity_errors.len() == prev_ambiguity_errors_len;
         import.vis.set(orig_vis);
         let module = match path_res {
             PathResult::Module(module) => {
@@ -703,10 +694,10 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     if !ModuleOrUniformRoot::same_def(module, initial_module) && no_ambiguity {
                         span_bug!(import.span, "inconsistent resolution for an import");
                     }
-                } else if self.r.privacy_errors.is_empty() {
+                } else if self.privacy_errors.is_empty() {
                     let msg = "cannot determine resolution for the import";
                     let msg_note = "import resolution is stuck, try simplifying other imports";
-                    self.r.session.struct_span_err(import.span, msg).note(msg_note).emit();
+                    self.tcx.sess.struct_span_err(import.span, msg).note(msg_note).emit();
                 }
 
                 module
@@ -714,8 +705,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
                 if no_ambiguity {
                     assert!(import.imported_module.get().is_none());
-                    self.r
-                        .report_error(span, ResolutionError::FailedToResolve { label, suggestion });
+                    self.report_error(span, ResolutionError::FailedToResolve { label, suggestion });
                 }
                 return None;
             }
@@ -777,7 +767,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                         // 2 segments, so the `resolve_path` above won't trigger it.
                         let mut full_path = import.module_path.clone();
                         full_path.push(Segment::from_ident(Ident::empty()));
-                        self.r.lint_if_path_starts_with_module(Some(finalize), &full_path, None);
+                        self.lint_if_path_starts_with_module(Some(finalize), &full_path, None);
                     }
 
                     if let ModuleOrUniformRoot::Module(module) = module {
@@ -796,10 +786,10 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     }
                     if !is_prelude
                     && let Some(max_vis) = max_vis.get()
-                    && !max_vis.is_at_least(import.expect_vis(), &*self.r)
+                    && !max_vis.is_at_least(import.expect_vis(), &*self)
                 {
                     let msg = "glob import doesn't reexport anything because no candidate is public enough";
-                    self.r.lint_buffer.buffer_lint(UNUSED_IMPORTS, id, import.span, msg);
+                    self.lint_buffer.buffer_lint(UNUSED_IMPORTS, id, import.span, msg);
                 }
                     return None;
                 }
@@ -807,7 +797,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             };
 
         let mut all_ns_err = true;
-        self.r.per_ns(|this, ns| {
+        self.per_ns(|this, ns| {
             if !type_ns_only || ns == TypeNS {
                 let orig_vis = import.vis.take();
                 let binding = this.resolve_ident_in_module(
@@ -859,7 +849,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                             let msg = "cannot determine resolution for the import";
                             let msg_note =
                                 "import resolution is stuck, try simplifying other imports";
-                            this.session.struct_span_err(import.span, msg).note(msg_note).emit();
+                            this.tcx.sess.struct_span_err(import.span, msg).note(msg_note).emit();
                         }
                     }
                     Err(..) => {
@@ -876,7 +866,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
         if all_ns_err {
             let mut all_ns_failed = true;
-            self.r.per_ns(|this, ns| {
+            self.per_ns(|this, ns| {
                 if !type_ns_only || ns == TypeNS {
                     let binding = this.resolve_ident_in_module(
                         module,
@@ -894,9 +884,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
             return if all_ns_failed {
                 let resolutions = match module {
-                    ModuleOrUniformRoot::Module(module) => {
-                        Some(self.r.resolutions(module).borrow())
-                    }
+                    ModuleOrUniformRoot::Module(module) => Some(self.resolutions(module).borrow()),
                     _ => None,
                 };
                 let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter());
@@ -965,7 +953,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                 };
 
                 let parent_suggestion =
-                    self.r.lookup_import_candidates(ident, TypeNS, &import.parent_scope, |_| true);
+                    self.lookup_import_candidates(ident, TypeNS, &import.parent_scope, |_| true);
 
                 Some(UnresolvedImportError {
                     span: import.span,
@@ -987,7 +975,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         let mut reexport_error = None;
         let mut any_successful_reexport = false;
         let mut crate_private_reexport = false;
-        self.r.per_ns(|this, ns| {
+        self.per_ns(|this, ns| {
             if let Ok(binding) = source_bindings[ns].get() {
                 if !binding.vis.is_at_least(import.expect_vis(), &*this) {
                     reexport_error = Some((ns, binding));
@@ -1012,7 +1000,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                                    `pub`",
                     ident
                 );
-                self.r.lint_buffer.buffer_lint(
+                self.lint_buffer.buffer_lint(
                     PUB_USE_OF_PRIVATE_EXTERN_CRATE,
                     import_id,
                     import.span,
@@ -1035,17 +1023,17 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                         format!("re-export of private `{}`", ident)
                     };
 
-                    struct_span_err!(self.r.session, import.span, E0365, "{}", error_msg)
+                    struct_span_err!(self.tcx.sess, import.span, E0365, "{}", error_msg)
                         .span_label(import.span, label_msg)
                         .note(&format!("consider declaring type or module `{}` with `pub`", ident))
                         .emit();
                 } else {
                     let mut err =
-                        struct_span_err!(self.r.session, import.span, E0364, "{error_msg}");
+                        struct_span_err!(self.tcx.sess, import.span, E0364, "{error_msg}");
                     match binding.kind {
                         NameBindingKind::Res(Res::Def(DefKind::Macro(_), def_id))
                             // exclude decl_macro
-                            if self.r.get_macro_by_def_id(def_id).macro_rules =>
+                            if self.get_macro_by_def_id(def_id).macro_rules =>
                         {
                             err.span_help(
                                 binding.span,
@@ -1071,7 +1059,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             // 2 segments, so the `resolve_path` above won't trigger it.
             let mut full_path = import.module_path.clone();
             full_path.push(Segment::from_ident(ident));
-            self.r.per_ns(|this, ns| {
+            self.per_ns(|this, ns| {
                 if let Ok(binding) = source_bindings[ns].get() {
                     this.lint_if_path_starts_with_module(Some(finalize), &full_path, Some(binding));
                 }
@@ -1081,7 +1069,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         // Record what this import resolves to for later uses in documentation,
         // this may resolve to either a value or a type, but for documentation
         // purposes it's good enough to just favor one over the other.
-        self.r.per_ns(|this, ns| {
+        self.per_ns(|this, ns| {
             if let Ok(binding) = source_bindings[ns].get() {
                 this.import_res_map.entry(import_id).or_default()[ns] = Some(binding.res());
             }
@@ -1096,9 +1084,9 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
     fn check_for_redundant_imports(
         &mut self,
         ident: Ident,
-        import: &'b Import<'b>,
-        source_bindings: &PerNS<Cell<Result<&'b NameBinding<'b>, Determinacy>>>,
-        target_bindings: &PerNS<Cell<Option<&'b NameBinding<'b>>>>,
+        import: &'a Import<'a>,
+        source_bindings: &PerNS<Cell<Result<&'a NameBinding<'a>, Determinacy>>>,
+        target_bindings: &PerNS<Cell<Option<&'a NameBinding<'a>>>>,
         target: Ident,
     ) {
         // This function is only called for single imports.
@@ -1119,7 +1107,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
         let mut redundant_span = PerNS { value_ns: None, type_ns: None, macro_ns: None };
 
-        self.r.per_ns(|this, ns| {
+        self.per_ns(|this, ns| {
             if let Ok(binding) = source_bindings[ns].get() {
                 if binding.res() == Res::Err {
                     return;
@@ -1149,7 +1137,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             let mut redundant_spans: Vec<_> = redundant_span.present_items().collect();
             redundant_spans.sort();
             redundant_spans.dedup();
-            self.r.lint_buffer.buffer_lint_with_diagnostic(
+            self.lint_buffer.buffer_lint_with_diagnostic(
                 UNUSED_IMPORTS,
                 id,
                 import.span,
@@ -1159,22 +1147,22 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         }
     }
 
-    fn resolve_glob_import(&mut self, import: &'b Import<'b>) {
+    fn resolve_glob_import(&mut self, import: &'a Import<'a>) {
         // This function is only called for glob imports.
         let ImportKind::Glob { id, is_prelude, .. } = import.kind else { unreachable!() };
 
         let ModuleOrUniformRoot::Module(module) = import.imported_module.get().unwrap() else {
-            self.r.session.span_err(import.span, "cannot glob-import all possible crates");
+            self.tcx.sess.span_err(import.span, "cannot glob-import all possible crates");
             return;
         };
 
         if module.is_trait() {
-            self.r.session.span_err(import.span, "items in traits are not importable");
+            self.tcx.sess.span_err(import.span, "items in traits are not importable");
             return;
         } else if ptr::eq(module, import.parent_scope.module) {
             return;
         } else if is_prelude {
-            self.r.prelude = Some(module);
+            self.prelude = Some(module);
             return;
         }
 
@@ -1184,7 +1172,6 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         // Ensure that `resolutions` isn't borrowed during `try_define`,
         // since it might get updated via a glob cycle.
         let bindings = self
-            .r
             .resolutions(module)
             .borrow()
             .iter()
@@ -1194,30 +1181,30 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             .collect::<Vec<_>>();
         for (mut key, binding) in bindings {
             let scope = match key.ident.span.reverse_glob_adjust(module.expansion, import.span) {
-                Some(Some(def)) => self.r.expn_def_scope(def),
+                Some(Some(def)) => self.expn_def_scope(def),
                 Some(None) => import.parent_scope.module,
                 None => continue,
             };
-            if self.r.is_accessible_from(binding.vis, scope) {
-                let imported_binding = self.r.import(binding, import);
-                let _ = self.r.try_define(import.parent_scope.module, key, imported_binding);
+            if self.is_accessible_from(binding.vis, scope) {
+                let imported_binding = self.import(binding, import);
+                let _ = self.try_define(import.parent_scope.module, key, imported_binding);
             }
         }
 
         // Record the destination of this import
-        self.r.record_partial_res(id, PartialRes::new(module.res().unwrap()));
+        self.record_partial_res(id, PartialRes::new(module.res().unwrap()));
     }
 
     // Miscellaneous post-processing, including recording re-exports,
     // reporting conflicts, and reporting unresolved imports.
-    fn finalize_resolutions_in(&mut self, module: Module<'b>) {
+    fn finalize_resolutions_in(&mut self, module: Module<'a>) {
         // Since import resolution is finished, globs will not define any more names.
         *module.globs.borrow_mut() = Vec::new();
 
         if let Some(def_id) = module.opt_def_id() {
             let mut reexports = Vec::new();
 
-            module.for_each_child(self.r, |this, ident, _, binding| {
+            module.for_each_child(self, |this, ident, _, binding| {
                 if let Some(res) = this.is_reexport(binding) {
                     reexports.push(ModChild {
                         ident,
@@ -1232,7 +1219,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             if !reexports.is_empty() {
                 // Call to `expect_local` should be fine because current
                 // code is only called for local modules.
-                self.r.reexport_map.insert(def_id.expect_local(), reexports);
+                self.reexport_map.insert(def_id.expect_local(), reexports);
             }
         }
     }
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 83932c089..7df17376b 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -8,7 +8,7 @@
 
 use RibKind::*;
 
-use crate::{path_names_to_string, BindingError, Finalize, LexicalScopeBinding};
+use crate::{path_names_to_string, rustdoc, BindingError, Finalize, LexicalScopeBinding};
 use crate::{Module, ModuleOrUniformRoot, NameBinding, ParentScope, PathResult};
 use crate::{ResolutionError, Resolver, Segment, UseError};
 
@@ -21,15 +21,16 @@ use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind, LifetimeRes, PartialRes, PerNS};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::{BindingAnnotation, PrimTy, TraitCandidate};
-use rustc_middle::middle::resolve_lifetime::Set1;
+use rustc_middle::middle::resolve_bound_vars::Set1;
 use rustc_middle::ty::DefIdTree;
 use rustc_middle::{bug, span_bug};
+use rustc_session::config::{CrateType, ResolveDocLinks};
 use rustc_session::lint;
+use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{BytePos, Span};
+use rustc_span::{BytePos, Span, SyntaxContext};
 use smallvec::{smallvec, SmallVec};
 
-use rustc_span::source_map::{respan, Spanned};
 use std::assert_matches::debug_assert_matches;
 use std::borrow::Cow;
 use std::collections::{hash_map::Entry, BTreeSet};
@@ -55,7 +56,7 @@ struct BindingInfo {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub enum PatternSource {
+pub(crate) enum PatternSource {
     Match,
     Let,
     For,
@@ -69,7 +70,7 @@ enum IsRepeatExpr {
 }
 
 impl PatternSource {
-    pub fn descr(self) -> &'static str {
+    fn descr(self) -> &'static str {
         match self {
             PatternSource::Match => "match binding",
             PatternSource::Let => "let binding",
@@ -493,6 +494,30 @@ impl<'a> PathSource<'a> {
     }
 }
 
+/// At this point for most items we can answer whether that item is exported or not,
+/// but some items like impls require type information to determine exported-ness, so we make a
+/// conservative estimate for them (e.g. based on nominal visibility).
+#[derive(Clone, Copy)]
+enum MaybeExported<'a> {
+    Ok(NodeId),
+    Impl(Option<DefId>),
+    ImplItem(Result<DefId, &'a Visibility>),
+}
+
+impl MaybeExported<'_> {
+    fn eval(self, r: &Resolver<'_, '_>) -> bool {
+        let def_id = match self {
+            MaybeExported::Ok(node_id) => Some(r.local_def_id(node_id)),
+            MaybeExported::Impl(Some(trait_def_id)) | MaybeExported::ImplItem(Ok(trait_def_id)) => {
+                trait_def_id.as_local()
+            }
+            MaybeExported::Impl(None) => return true,
+            MaybeExported::ImplItem(Err(vis)) => return vis.kind.is_pub(),
+        };
+        def_id.map_or(true, |def_id| r.effective_visibilities.is_exported(def_id))
+    }
+}
+
 #[derive(Default)]
 struct DiagnosticMetadata<'ast> {
     /// The current trait's associated items' ident, used for diagnostic suggestions.
@@ -559,8 +584,8 @@ struct DiagnosticMetadata<'ast> {
     current_elision_failures: Vec<MissingLifetime>,
 }
 
-struct LateResolutionVisitor<'a, 'b, 'ast> {
-    r: &'b mut Resolver<'a>,
+struct LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
+    r: &'b mut Resolver<'a, 'tcx>,
 
     /// The module that represents the current item scope.
     parent_scope: ParentScope<'a>,
@@ -603,7 +628,7 @@ struct LateResolutionVisitor<'a, 'b, 'ast> {
 }
 
 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
-impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
+impl<'a: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
     fn visit_attribute(&mut self, _: &'ast Attribute) {
         // We do not want to resolve expressions that appear in attributes,
         // as they do not correspond to actual code.
@@ -620,7 +645,9 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
         self.resolve_arm(arm);
     }
     fn visit_block(&mut self, block: &'ast Block) {
+        let old_macro_rules = self.parent_scope.macro_rules;
         self.resolve_block(block);
+        self.parent_scope.macro_rules = old_macro_rules;
     }
     fn visit_anon_const(&mut self, constant: &'ast AnonConst) {
         // We deal with repeat expressions explicitly in `resolve_expr`.
@@ -655,7 +682,7 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
                 // Elided lifetime in reference: we resolve as if there was some lifetime `'_` with
                 // NodeId `ty.id`.
                 // This span will be used in case of elision failure.
-                let span = self.r.session.source_map().start_point(ty.span);
+                let span = self.r.tcx.sess.source_map().start_point(ty.span);
                 self.resolve_elided_lifetime(ty.id, span);
                 visit::walk_ty(self, ty);
             }
@@ -771,6 +798,7 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
         );
     }
     fn visit_foreign_item(&mut self, foreign_item: &'ast ForeignItem) {
+        self.resolve_doc_links(&foreign_item.attrs, MaybeExported::Ok(foreign_item.id));
         match foreign_item.kind {
             ForeignItemKind::TyAlias(box TyAlias { ref generics, .. }) => {
                 self.with_generic_param_rib(
@@ -1159,10 +1187,20 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
             })
         });
     }
+
+    fn visit_variant(&mut self, v: &'ast Variant) {
+        self.resolve_doc_links(&v.attrs, MaybeExported::Ok(v.id));
+        visit::walk_variant(self, v)
+    }
+
+    fn visit_field_def(&mut self, f: &'ast FieldDef) {
+        self.resolve_doc_links(&f.attrs, MaybeExported::Ok(f.id));
+        visit::walk_field_def(self, f)
+    }
 }
 
-impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
-    fn new(resolver: &'b mut Resolver<'a>) -> LateResolutionVisitor<'a, 'b, 'ast> {
+impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
+    fn new(resolver: &'b mut Resolver<'a, 'tcx>) -> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
         // During late resolution we only track the module component of the parent scope,
         // although it may be useful to track other components as well for diagnostics.
         let graph_root = resolver.graph_root;
@@ -1533,7 +1571,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                         ("`'_` cannot be used here", "`'_` is a reserved lifetime name")
                     };
                     let mut diag = rustc_errors::struct_span_err!(
-                        self.r.session,
+                        self.r.tcx.sess,
                         lifetime.ident.span,
                         E0637,
                         "{}",
@@ -1710,7 +1748,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                     //     impl Foo for std::cell::Ref<u32> // note lack of '_
                     //     async fn foo(_: std::cell::Ref<u32>) { ... }
                     LifetimeRibKind::AnonymousCreateParameter { report_in_path: true, .. } => {
-                        let sess = self.r.session;
+                        let sess = self.r.tcx.sess;
                         let mut err = rustc_errors::struct_span_err!(
                             sess,
                             path_span,
@@ -1725,7 +1763,6 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                             !segment.has_generic_args,
                             elided_lifetime_span,
                         );
-                        err.note("assuming a `'static` lifetime...");
                         err.emit();
                         should_lint = false;
 
@@ -1992,13 +2029,13 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
     /// List all the lifetimes that appear in the provided type.
     fn find_lifetime_for_self(&self, ty: &'ast Ty) -> Set1<LifetimeRes> {
-        struct SelfVisitor<'r, 'a> {
-            r: &'r Resolver<'a>,
+        struct SelfVisitor<'r, 'a, 'tcx> {
+            r: &'r Resolver<'a, 'tcx>,
             impl_self: Option<Res>,
             lifetime: Set1<LifetimeRes>,
         }
 
-        impl SelfVisitor<'_, '_> {
+        impl SelfVisitor<'_, '_, '_> {
             // Look for `self: &'a Self` - also desugared from `&'a self`,
             // and if that matches, use it for elision and return early.
             fn is_self_ty(&self, ty: &Ty) -> bool {
@@ -2016,7 +2053,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             }
         }
 
-        impl<'a> Visitor<'a> for SelfVisitor<'_, '_> {
+        impl<'a> Visitor<'a> for SelfVisitor<'_, '_, '_> {
             fn visit_ty(&mut self, ty: &'a Ty) {
                 trace!("SelfVisitor considering ty={:?}", ty);
                 if let TyKind::Ref(lt, ref mt) = ty.kind && self.is_self_ty(&mt.ty) {
@@ -2145,7 +2182,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         let segments = &use_tree.prefix.segments;
         if !segments.is_empty() {
             let ident = segments[0].ident;
-            if ident.is_path_segment_keyword() || ident.span.rust_2015() {
+            if ident.is_path_segment_keyword() || ident.span.is_rust_2015() {
                 return;
             }
 
@@ -2157,7 +2194,8 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
                 if this.should_report_errs() {
                     this.r
-                        .session
+                        .tcx
+                        .sess
                         .span_err(ident.span, &format!("imports cannot refer to {}", what));
                 }
             };
@@ -2185,6 +2223,12 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
     }
 
     fn resolve_item(&mut self, item: &'ast Item) {
+        let mod_inner_docs =
+            matches!(item.kind, ItemKind::Mod(..)) && rustdoc::inner_docs(&item.attrs);
+        if !mod_inner_docs && !matches!(item.kind, ItemKind::Impl(..)) {
+            self.resolve_doc_links(&item.attrs, MaybeExported::Ok(item.id));
+        }
+
         let name = item.ident.name;
         debug!("(resolving item) resolving {} ({:?})", name, item.kind);
 
@@ -2229,7 +2273,14 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 ..
             }) => {
                 self.diagnostic_metadata.current_impl_items = Some(impl_items);
-                self.resolve_implementation(generics, of_trait, &self_ty, item.id, impl_items);
+                self.resolve_implementation(
+                    &item.attrs,
+                    generics,
+                    of_trait,
+                    &self_ty,
+                    item.id,
+                    impl_items,
+                );
                 self.diagnostic_metadata.current_impl_items = None;
             }
 
@@ -2274,9 +2325,20 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 );
             }
 
-            ItemKind::Mod(..) | ItemKind::ForeignMod(_) => {
+            ItemKind::Mod(..) => {
                 self.with_scope(item.id, |this| {
+                    if mod_inner_docs {
+                        this.resolve_doc_links(&item.attrs, MaybeExported::Ok(item.id));
+                    }
+                    let old_macro_rules = this.parent_scope.macro_rules;
                     visit::walk_item(this, item);
+                    // Maintain macro_rules scopes in the same way as during early resolution
+                    // for diagnostics and doc links.
+                    if item.attrs.iter().all(|attr| {
+                        !attr.has_name(sym::macro_use) && !attr.has_name(sym::macro_escape)
+                    }) {
+                        this.parent_scope.macro_rules = old_macro_rules;
+                    }
                 });
             }
 
@@ -2309,14 +2371,21 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 self.future_proof_import(use_tree);
             }
 
-            ItemKind::ExternCrate(..) | ItemKind::MacroDef(..) => {
-                // do nothing, these are just around to be encoded
+            ItemKind::MacroDef(ref macro_def) => {
+                // Maintain macro_rules scopes in the same way as during early resolution
+                // for diagnostics and doc links.
+                if macro_def.macro_rules {
+                    let def_id = self.r.local_def_id(item.id);
+                    self.parent_scope.macro_rules = self.r.macro_rules_scopes[&def_id];
+                }
             }
 
-            ItemKind::GlobalAsm(_) => {
+            ItemKind::ForeignMod(_) | ItemKind::GlobalAsm(_) => {
                 visit::walk_item(self, item);
             }
 
+            ItemKind::ExternCrate(..) => {}
+
             ItemKind::MacCall(_) => panic!("unexpanded macro in resolve!"),
         }
     }
@@ -2370,7 +2439,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             if let GenericParamKind::Lifetime = param.kind
                 && let Some(&original) = seen_lifetimes.get(&ident)
             {
-                diagnostics::signal_lifetime_shadowing(self.r.session, original, param.ident);
+                diagnostics::signal_lifetime_shadowing(self.r.tcx.sess, original, param.ident);
                 // Record lifetime res, so lowering knows there is something fishy.
                 self.record_lifetime_param(param.id, LifetimeRes::Error);
                 continue;
@@ -2394,7 +2463,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
             if param.ident.name == kw::UnderscoreLifetime {
                 rustc_errors::struct_span_err!(
-                    self.r.session,
+                    self.r.tcx.sess,
                     param.ident.span,
                     E0637,
                     "`'_` cannot be used here"
@@ -2408,7 +2477,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
             if param.ident.name == kw::StaticLifetime {
                 rustc_errors::struct_span_err!(
-                    self.r.session,
+                    self.r.tcx.sess,
                     param.ident.span,
                     E0262,
                     "invalid lifetime parameter name: `{}`",
@@ -2437,7 +2506,13 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
             let res = match kind {
                 ItemRibKind(..) | AssocItemRibKind => Res::Def(def_kind, def_id.to_def_id()),
-                NormalRibKind => Res::Err,
+                NormalRibKind => {
+                    if self.r.tcx.sess.features_untracked().non_lifetime_binders {
+                        Res::Def(def_kind, def_id.to_def_id())
+                    } else {
+                        Res::Err
+                    }
+                }
                 _ => span_bug!(param.ident.span, "Unexpected rib kind {:?}", kind),
             };
             self.r.record_partial_res(param.id, PartialRes::new(res));
@@ -2544,6 +2619,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             };
 
         for item in trait_items {
+            self.resolve_doc_links(&item.attrs, MaybeExported::Ok(item.id));
             match &item.kind {
                 AssocItemKind::Const(_, ty, default) => {
                     self.visit_ty(ty);
@@ -2631,6 +2707,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
     fn resolve_implementation(
         &mut self,
+        attrs: &[ast::Attribute],
         generics: &'ast Generics,
         opt_trait_reference: &'ast Option<TraitRef>,
         self_type: &'ast Ty,
@@ -2661,6 +2738,8 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                                 opt_trait_reference.as_ref(),
                                 self_type,
                                 |this, trait_id| {
+                                    this.resolve_doc_links(attrs, MaybeExported::Impl(trait_id));
+
                                     let item_def_id = this.r.local_def_id(item_id);
 
                                     // Register the trait definitions from here.
@@ -2694,7 +2773,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                                                 debug!("resolve_implementation with_self_rib_ns(ValueNS, ...)");
                                                 let mut seen_trait_items = Default::default();
                                                 for item in impl_items {
-                                                    this.resolve_impl_item(&**item, &mut seen_trait_items);
+                                                    this.resolve_impl_item(&**item, &mut seen_trait_items, trait_id);
                                                 }
                                             });
                                         });
@@ -2712,8 +2791,10 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         &mut self,
         item: &'ast AssocItem,
         seen_trait_items: &mut FxHashMap<DefId, Span>,
+        trait_id: Option<DefId>,
     ) {
         use crate::ResolutionError::*;
+        self.resolve_doc_links(&item.attrs, MaybeExported::ImplItem(trait_id.ok_or(&item.vis)));
         match &item.kind {
             AssocItemKind::Const(_, ty, default) => {
                 debug!("resolve_implementation AssocItemKind::Const");
@@ -3304,7 +3385,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             Res::SelfCtor(_) => {
                 // We resolve `Self` in pattern position as an ident sometimes during recovery,
                 // so delay a bug instead of ICEing.
-                self.r.session.delay_span_bug(
+                self.r.tcx.sess.delay_span_bug(
                     ident.span,
                     "unexpected `SelfCtor` in pattern, expected identifier"
                 );
@@ -3584,7 +3665,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
     #[inline]
     /// If we're actually rustdoc then avoid giving a name resolution error for `cfg()` items.
     fn should_report_errs(&self) -> bool {
-        !(self.r.session.opts.actually_rustdoc && self.in_func_body)
+        !(self.r.tcx.sess.opts.actually_rustdoc && self.in_func_body)
     }
 
     // Resolve in alternative namespaces if resolution in the primary namespace fails.
@@ -3749,7 +3830,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             }
 
             if let Ok((_, orig_span)) = self.resolve_label(label.ident) {
-                diagnostics::signal_label_shadowing(self.r.session, orig_span, label.ident)
+                diagnostics::signal_label_shadowing(self.r.tcx.sess, orig_span, label.ident)
             }
 
             self.with_label_rib(NormalRibKind, |this| {
@@ -4055,9 +4136,9 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
     fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &'ast Expr) {
         match expr.kind {
             ExprKind::Field(_, ident) => {
-                // FIXME(#6890): Even though you can't treat a method like a
-                // field, we need to add any trait methods we find that match
-                // the field name so that we can do some nice error reporting
+                // #6890: Even though you can't treat a method like a field,
+                // we need to add any trait methods we find that match the
+                // field name so that we can do some nice error reporting
                 // later on in typeck.
                 let traits = self.traits_in_scope(ident, ValueNS);
                 self.r.trait_map.insert(expr.id, traits);
@@ -4116,15 +4197,116 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             self.r.extra_lifetime_params_map.insert(async_node_id, extra_lifetime_params);
         }
     }
+
+    fn resolve_and_cache_rustdoc_path(&mut self, path_str: &str, ns: Namespace) -> bool {
+        // FIXME: This caching may be incorrect in case of multiple `macro_rules`
+        // items with the same name in the same module.
+        // Also hygiene is not considered.
+        let mut doc_link_resolutions = std::mem::take(&mut self.r.doc_link_resolutions);
+        let res = doc_link_resolutions
+            .entry(self.parent_scope.module.nearest_parent_mod().expect_local())
+            .or_default()
+            .entry((Symbol::intern(path_str), ns))
+            .or_insert_with_key(|(path, ns)| {
+                let res = self.r.resolve_rustdoc_path(path.as_str(), *ns, self.parent_scope);
+                if let Some(res) = res
+                    && let Some(def_id) = res.opt_def_id()
+                    && !def_id.is_local()
+                    && self.r.tcx.sess.crate_types().contains(&CrateType::ProcMacro)
+                    && matches!(self.r.tcx.sess.opts.resolve_doc_links, ResolveDocLinks::ExportedMetadata) {
+                    // Encoding foreign def ids in proc macro crate metadata will ICE.
+                    return None;
+                }
+                res
+            })
+            .is_some();
+        self.r.doc_link_resolutions = doc_link_resolutions;
+        res
+    }
+
+    fn resolve_doc_links(&mut self, attrs: &[Attribute], maybe_exported: MaybeExported<'_>) {
+        match self.r.tcx.sess.opts.resolve_doc_links {
+            ResolveDocLinks::None => return,
+            ResolveDocLinks::ExportedMetadata
+                if !self.r.tcx.sess.crate_types().iter().copied().any(CrateType::has_metadata)
+                    || !maybe_exported.eval(self.r) =>
+            {
+                return;
+            }
+            ResolveDocLinks::Exported if !maybe_exported.eval(self.r) => {
+                return;
+            }
+            ResolveDocLinks::ExportedMetadata
+            | ResolveDocLinks::Exported
+            | ResolveDocLinks::All => {}
+        }
+
+        if !attrs.iter().any(|attr| attr.may_have_doc_links()) {
+            return;
+        }
+
+        let mut need_traits_in_scope = false;
+        for path_str in rustdoc::attrs_to_preprocessed_links(attrs) {
+            // Resolve all namespaces due to no disambiguator or for diagnostics.
+            let mut any_resolved = false;
+            let mut need_assoc = false;
+            for ns in [TypeNS, ValueNS, MacroNS] {
+                if self.resolve_and_cache_rustdoc_path(&path_str, ns) {
+                    any_resolved = true;
+                } else if ns != MacroNS {
+                    need_assoc = true;
+                }
+            }
+
+            // Resolve all prefixes for type-relative resolution or for diagnostics.
+            if need_assoc || !any_resolved {
+                let mut path = &path_str[..];
+                while let Some(idx) = path.rfind("::") {
+                    path = &path[..idx];
+                    need_traits_in_scope = true;
+                    for ns in [TypeNS, ValueNS, MacroNS] {
+                        self.resolve_and_cache_rustdoc_path(path, ns);
+                    }
+                }
+            }
+        }
+
+        if need_traits_in_scope {
+            // FIXME: hygiene is not considered.
+            let mut doc_link_traits_in_scope = std::mem::take(&mut self.r.doc_link_traits_in_scope);
+            doc_link_traits_in_scope
+                .entry(self.parent_scope.module.nearest_parent_mod().expect_local())
+                .or_insert_with(|| {
+                    self.r
+                        .traits_in_scope(None, &self.parent_scope, SyntaxContext::root(), None)
+                        .into_iter()
+                        .filter_map(|tr| {
+                            if !tr.def_id.is_local()
+                                && self.r.tcx.sess.crate_types().contains(&CrateType::ProcMacro)
+                                && matches!(
+                                    self.r.tcx.sess.opts.resolve_doc_links,
+                                    ResolveDocLinks::ExportedMetadata
+                                )
+                            {
+                                // Encoding foreign def ids in proc macro crate metadata will ICE.
+                                return None;
+                            }
+                            Some(tr.def_id)
+                        })
+                        .collect()
+                });
+            self.r.doc_link_traits_in_scope = doc_link_traits_in_scope;
+        }
+    }
 }
 
-struct LifetimeCountVisitor<'a, 'b> {
-    r: &'b mut Resolver<'a>,
+struct LifetimeCountVisitor<'a, 'b, 'tcx> {
+    r: &'b mut Resolver<'a, 'tcx>,
 }
 
 /// Walks the whole crate in DFS order, visiting each item, counting the declared number of
 /// lifetime generic parameters.
-impl<'ast> Visitor<'ast> for LifetimeCountVisitor<'_, '_> {
+impl<'ast> Visitor<'ast> for LifetimeCountVisitor<'_, '_, '_> {
     fn visit_item(&mut self, item: &'ast Item) {
         match &item.kind {
             ItemKind::TyAlias(box TyAlias { ref generics, .. })
@@ -4158,10 +4340,11 @@ impl<'ast> Visitor<'ast> for LifetimeCountVisitor<'_, '_> {
     }
 }
 
-impl<'a> Resolver<'a> {
+impl<'a, 'tcx> Resolver<'a, 'tcx> {
     pub(crate) fn late_resolve_crate(&mut self, krate: &Crate) {
         visit::walk_crate(&mut LifetimeCountVisitor { r: self }, krate);
         let mut late_resolution_visitor = LateResolutionVisitor::new(self);
+        late_resolution_visitor.resolve_doc_links(&krate.attrs, MaybeExported::Ok(CRATE_NODE_ID));
         visit::walk_crate(&mut late_resolution_visitor, krate);
         for (id, span) in late_resolution_visitor.diagnostic_metadata.unused_labels.iter() {
             self.lint_buffer.buffer_lint(lint::builtin::UNUSED_LABELS, *id, *span, "unused label");
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 6d448433e..b8ddc4552 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -25,9 +25,9 @@ use rustc_middle::ty::DefIdTree;
 use rustc_session::lint;
 use rustc_session::parse::feature_err;
 use rustc_session::Session;
+use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::MacroKind;
-use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Span};
 
@@ -166,11 +166,11 @@ impl TypoCandidate {
     }
 }
 
-impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
+impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
     fn def_span(&self, def_id: DefId) -> Option<Span> {
         match def_id.krate {
             LOCAL_CRATE => self.r.opt_span(def_id),
-            _ => Some(self.r.cstore().get_span_untracked(def_id, self.r.session)),
+            _ => Some(self.r.cstore().get_span_untracked(def_id, self.r.tcx.sess)),
         }
     }
 
@@ -200,7 +200,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                     Res::Def(DefKind::Fn, _) => {
                         // Verify whether this is a fn call or an Fn used as a type.
                         self.r
-                            .session
+                            .tcx
+                            .sess
                             .source_map()
                             .span_to_snippet(span)
                             .map(|snippet| snippet.ends_with(')'))
@@ -227,20 +228,27 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                     && let Some(FnCtxt::Assoc(_)) = fn_kind.ctxt()
                     && let Some(items) = self.diagnostic_metadata.current_impl_items
                     && let Some(item) = items.iter().find(|i| {
-                        if let AssocItemKind::Fn(_) = &i.kind && i.ident.name == item_str.name
+                        if let AssocItemKind::Fn(..) | AssocItemKind::Const(..) = &i.kind
+                            && i.ident.name == item_str.name
                         {
                             debug!(?item_str.name);
                             return true
                         }
                         false
                     })
-                    && let AssocItemKind::Fn(fn_) = &item.kind
                 {
-                    debug!(?fn_);
-                    let self_sugg = if fn_.sig.decl.has_self() { "self." } else { "Self::" };
+                    let self_sugg = match &item.kind {
+                        AssocItemKind::Fn(fn_) if fn_.sig.decl.has_self() => "self.",
+                        _ => "Self::",
+                    };
+
                     Some((
                         item_span.shrink_to_lo(),
-                        "consider using the associated function",
+                        match &item.kind {
+                            AssocItemKind::Fn(..) => "consider using the associated function",
+                            AssocItemKind::Const(..) => "consider using the associated constant",
+                            _ => unreachable!("item kind was filtered above"),
+                        },
                         self_sugg.to_string()
                     ))
                 } else {
@@ -248,7 +256,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 };
                 (String::new(), "this scope".to_string(), suggestion)
             } else if path.len() == 2 && path[0].ident.name == kw::PathRoot {
-                if self.r.session.edition() > Edition::Edition2015 {
+                if self.r.tcx.sess.edition() > Edition::Edition2015 {
                     // In edition 2018 onwards, the `::foo` syntax may only pull from the extern prelude
                     // which overrides all other expectations of item type
                     expected = "crate";
@@ -311,12 +319,12 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         span: Span,
         source: PathSource<'_>,
         res: Option<Res>,
-    ) -> (DiagnosticBuilder<'a, ErrorGuaranteed>, Vec<ImportSuggestion>) {
+    ) -> (DiagnosticBuilder<'tcx, ErrorGuaranteed>, Vec<ImportSuggestion>) {
         debug!(?res, ?source);
         let base_error = self.make_base_error(path, span, source, res);
         let code = source.error_code(res.is_some());
         let mut err =
-            self.r.session.struct_span_err_with_code(base_error.span, &base_error.msg, code);
+            self.r.tcx.sess.struct_span_err_with_code(base_error.span, &base_error.msg, code);
 
         self.suggest_swapping_misplaced_self_ty_and_trait(&mut err, source, res, base_error.span);
 
@@ -425,7 +433,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                     } else {
                         (
                             self.r
-                                .session
+                                .tcx
+                                .sess
                                 .source_map()
                                 .span_through_char(*fn_span, '(')
                                 .shrink_to_hi(),
@@ -498,7 +507,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 {
                     if self
                         .r
-                        .session
+                        .tcx
+                        .sess
                         .parse_sess
                         .type_ascription_path_suggestions
                         .borrow()
@@ -535,7 +545,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             }
         }
 
-        // Try Levenshtein algorithm.
+        // Try finding a suitable replacement.
         let typo_sugg =
             self.lookup_typo_candidate(path, source.namespace(), is_expected).to_opt_suggestion();
         if path.len() == 1 && self.self_type_is_available() {
@@ -589,7 +599,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             if let Some((call_span, args_span)) = self.call_has_self_arg(source) {
                 let mut args_snippet = String::new();
                 if let Some(args_span) = args_span {
-                    if let Ok(snippet) = self.r.session.source_map().span_to_snippet(args_span) {
+                    if let Ok(snippet) = self.r.tcx.sess.source_map().span_to_snippet(args_span) {
                         args_snippet = snippet;
                     }
                 }
@@ -725,7 +735,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         let ident_span = path.last().map_or(span, |ident| ident.ident.span);
         let typo_sugg = self.lookup_typo_candidate(path, source.namespace(), is_expected);
         let is_in_same_file = &|sp1, sp2| {
-            let source_map = self.r.session.source_map();
+            let source_map = self.r.tcx.sess.source_map();
             let file1 = source_map.span_to_filename(sp1);
             let file2 = source_map.span_to_filename(sp2);
             file1 == file2
@@ -763,7 +773,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 _ => {}
             }
 
-            // If the trait has a single item (which wasn't matched by Levenshtein), suggest it
+            // If the trait has a single item (which wasn't matched by the algorithm), suggest it
             let suggestion = self.get_single_associated_item(&path, &source, is_expected);
             if !self.r.add_typo_suggestion(err, suggestion, ident_span) {
                 fallback = !self.let_binding_suggestion(err, ident_span);
@@ -868,7 +878,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         );
         let is_assoc_fn = self.self_type_is_available();
         if let Some((fn_kind, span)) = &self.diagnostic_metadata.current_function {
-            // The current function has a `self' parameter, but we were unable to resolve
+            // The current function has a `self` parameter, but we were unable to resolve
             // a reference to `self`. This can only happen if the `self` identifier we
             // are resolving came from a different hygiene context.
             if fn_kind.decl().inputs.get(0).map_or(false, |p| p.is_self()) {
@@ -888,7 +898,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                                 .map_or(*span, |ident| span.with_lo(ident.span.hi()));
                             (
                                 self.r
-                                    .session
+                                    .tcx
+                                    .sess
                                     .source_map()
                                     .span_through_char(span, '(')
                                     .shrink_to_hi(),
@@ -942,9 +953,9 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             && let PathSource::Trait(_) = source
             && let Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)) = res
             && let Ok(self_ty_str) =
-                self.r.session.source_map().span_to_snippet(self_ty.span)
+                self.r.tcx.sess.source_map().span_to_snippet(self_ty.span)
             && let Ok(trait_ref_str) =
-                self.r.session.source_map().span_to_snippet(trait_ref.path.span)
+                self.r.tcx.sess.source_map().span_to_snippet(trait_ref.path.span)
         {
                 err.multipart_suggestion(
                     "`impl` items mention the trait being implemented first and the type it is being implemented for second",
@@ -1088,7 +1099,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                             format!(
                                 "{}: {}<{} = {}>",
                                 self.r
-                                    .session
+                                    .tcx
+                                    .sess
                                     .source_map()
                                     .span_to_snippet(ty.span) // Account for `<&'a T as Foo>::Bar`.
                                     .unwrap_or_else(|_| constrain_ident.to_string()),
@@ -1157,7 +1169,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         // parser issue where a struct literal is being used on an expression
         // where a brace being opened means a block is being started. Look
         // ahead for the next text to see if `span` is followed by a `{`.
-        let sm = self.r.session.source_map();
+        let sm = self.r.tcx.sess.source_map();
         let sp = sm.span_look_ahead(span, None, Some(50));
         let followed_by_brace = matches!(sm.span_to_snippet(sp), Ok(ref snippet) if snippet == "{");
         // In case this could be a struct literal that needs to be surrounded
@@ -1205,7 +1217,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 true
             } else if kind == DefKind::Struct
             && let Some(lhs_source_span) = lhs_span.find_ancestor_inside(expr.span)
-            && let Ok(snippet) = self.r.session.source_map().span_to_snippet(lhs_source_span)
+            && let Ok(snippet) = self.r.tcx.sess.source_map().span_to_snippet(lhs_source_span)
             {
                 // The LHS is a type that originates from a macro call.
                 // We have to add angle brackets around it.
@@ -1336,7 +1348,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                     "!",
                     Applicability::MaybeIncorrect,
                 );
-                if path_str == "try" && span.rust_2015() {
+                if path_str == "try" && span.is_rust_2015() {
                     err.note("if you want the `try` keyword, you need Rust 2018 or later");
                 }
             }
@@ -1345,11 +1357,11 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             }
             (Res::Def(DefKind::TyAlias, def_id), PathSource::Trait(_)) => {
                 err.span_label(span, "type aliases cannot be used as traits");
-                if self.r.session.is_nightly_build() {
+                if self.r.tcx.sess.is_nightly_build() {
                     let msg = "you might have meant to use `#![feature(trait_alias)]` instead of a \
                                `type` alias";
                     if let Some(span) = self.def_span(def_id) {
-                        if let Ok(snip) = self.r.session.source_map().span_to_snippet(span) {
+                        if let Ok(snip) = self.r.tcx.sess.source_map().span_to_snippet(span) {
                             // The span contains a type alias so we should be able to
                             // replace `type` with `trait`.
                             let snip = snip.replacen("type", "trait", 1);
@@ -1380,7 +1392,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                     .last()
                     .map(|sp| {
                         self.r
-                            .session
+                            .tcx
+                            .sess
                             .parse_sess
                             .type_ascription_path_suggestions
                             .borrow()
@@ -1687,17 +1700,14 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                             let extern_prelude = self.r.extern_prelude.clone();
                             names.extend(extern_prelude.iter().flat_map(|(ident, _)| {
                                 self.r
-                                    .crate_loader()
-                                    .maybe_process_path_extern(ident.name)
+                                    .crate_loader(|c| c.maybe_process_path_extern(ident.name))
                                     .and_then(|crate_id| {
                                         let crate_mod =
                                             Res::Def(DefKind::Mod, crate_id.as_def_id());
 
-                                        if filter_fn(crate_mod) {
-                                            Some(TypoSuggestion::typo_from_ident(*ident, crate_mod))
-                                        } else {
-                                            None
-                                        }
+                                        filter_fn(crate_mod).then(|| {
+                                            TypoSuggestion::typo_from_ident(*ident, crate_mod)
+                                        })
                                     })
                             }));
 
@@ -1769,12 +1779,12 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
 
     /// Only used in a specific case of type ascription suggestions
     fn get_colon_suggestion_span(&self, start: Span) -> Span {
-        let sm = self.r.session.source_map();
+        let sm = self.r.tcx.sess.source_map();
         start.to(sm.next_point(start))
     }
 
     fn type_ascription_suggestion(&self, err: &mut Diagnostic, base_span: Span) -> bool {
-        let sm = self.r.session.source_map();
+        let sm = self.r.tcx.sess.source_map();
         let base_snippet = sm.span_to_snippet(base_span);
         if let Some(&sp) = self.diagnostic_metadata.current_type_ascription.last() {
             if let Ok(snippet) = sm.span_to_snippet(sp) {
@@ -1804,7 +1814,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                             show_label = false;
                             if !self
                                 .r
-                                .session
+                                .tcx
+                                .sess
                                 .parse_sess
                                 .type_ascription_path_suggestions
                                 .borrow_mut()
@@ -2237,19 +2248,23 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 }
                 None => {
                     debug!(?param.ident, ?param.ident.span);
-
                     let deletion_span = deletion_span();
-                    self.r.lint_buffer.buffer_lint_with_diagnostic(
-                        lint::builtin::UNUSED_LIFETIMES,
-                        param.id,
-                        param.ident.span,
-                        &format!("lifetime parameter `{}` never used", param.ident),
-                        lint::BuiltinLintDiagnostics::SingleUseLifetime {
-                            param_span: param.ident.span,
-                            use_span: None,
-                            deletion_span,
-                        },
-                    );
+                    // the give lifetime originates from expanded code so we won't be able to remove it #104432
+                    let lifetime_only_in_expanded_code =
+                        deletion_span.map(|sp| sp.in_derive_expansion()).unwrap_or(true);
+                    if !lifetime_only_in_expanded_code {
+                        self.r.lint_buffer.buffer_lint_with_diagnostic(
+                            lint::builtin::UNUSED_LIFETIMES,
+                            param.id,
+                            param.ident.span,
+                            &format!("lifetime parameter `{}` never used", param.ident),
+                            lint::BuiltinLintDiagnostics::SingleUseLifetime {
+                                param_span: param.ident.span,
+                                use_span: None,
+                                deletion_span,
+                            },
+                        );
+                    }
                 }
             }
         }
@@ -2263,7 +2278,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         debug_assert_ne!(lifetime_ref.ident.name, kw::UnderscoreLifetime);
         let mut err = if let Some(outer) = outer_lifetime_ref {
             let mut err = struct_span_err!(
-                self.r.session,
+                self.r.tcx.sess,
                 lifetime_ref.ident.span,
                 E0401,
                 "can't use generic parameters from outer item",
@@ -2273,7 +2288,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             err
         } else {
             let mut err = struct_span_err!(
-                self.r.session,
+                self.r.tcx.sess,
                 lifetime_ref.ident.span,
                 E0261,
                 "use of undeclared lifetime name `{}`",
@@ -2331,8 +2346,13 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                         );
                         (span, sugg)
                     } else {
-                        let span =
-                            self.r.session.source_map().span_through_char(span, '<').shrink_to_hi();
+                        let span = self
+                            .r
+                            .tcx
+                            .sess
+                            .source_map()
+                            .span_through_char(span, '<')
+                            .shrink_to_hi();
                         let sugg = format!("{}, ", name.unwrap_or("'a"));
                         (span, sugg)
                     };
@@ -2366,7 +2386,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
 
     pub(crate) fn emit_non_static_lt_in_const_generic_error(&self, lifetime_ref: &ast::Lifetime) {
         struct_span_err!(
-            self.r.session,
+            self.r.tcx.sess,
             lifetime_ref.ident.span,
             E0771,
             "use of non-static lifetime `{}` in const generic",
@@ -2386,10 +2406,10 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         &self,
         lifetime_ref: &ast::Lifetime,
     ) {
-        let feature_active = self.r.session.features_untracked().generic_const_exprs;
+        let feature_active = self.r.tcx.sess.features_untracked().generic_const_exprs;
         if !feature_active {
             feature_err(
-                &self.r.session.parse_sess,
+                &self.r.tcx.sess.parse_sess,
                 sym::generic_const_exprs,
                 lifetime_ref.ident.span,
                 "a non-static lifetime is not allowed in a `const`",
@@ -2407,7 +2427,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         let spans: Vec<_> = lifetime_refs.iter().map(|lt| lt.span).collect();
 
         let mut err = struct_span_err!(
-            self.r.session,
+            self.r.tcx.sess,
             spans,
             E0106,
             "missing lifetime specifier{}",
@@ -2615,7 +2635,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
 }
 
 /// Report lifetime/lifetime shadowing as an error.
-pub fn signal_lifetime_shadowing(sess: &Session, orig: Ident, shadower: Ident) {
+pub(super) fn signal_lifetime_shadowing(sess: &Session, orig: Ident, shadower: Ident) {
     let mut err = struct_span_err!(
         sess,
         shadower.span,
@@ -2630,7 +2650,7 @@ pub fn signal_lifetime_shadowing(sess: &Session, orig: Ident, shadower: Ident) {
 
 /// Shadowing involving a label is only a warning for historical reasons.
 //FIXME: make this a proper lint.
-pub fn signal_label_shadowing(sess: &Session, orig: Span, shadower: Ident) {
+pub(super) fn signal_label_shadowing(sess: &Session, orig: Span, shadower: Ident) {
     let name = shadower.name;
     let shadower = shadower.span;
     let mut err = sess.struct_span_warn(
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 1b181b714..1fdfb1a53 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -21,34 +21,34 @@
 #[macro_use]
 extern crate tracing;
 
-pub use rustc_hir::def::{Namespace, PerNS};
-
 use rustc_arena::{DroplessArena, TypedArena};
 use rustc_ast::node_id::NodeMap;
 use rustc_ast::{self as ast, NodeId, CRATE_NODE_ID};
 use rustc_ast::{AngleBracketedArg, Crate, Expr, ExprKind, GenericArg, GenericArgs, LitKind, Path};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::intern::Interned;
-use rustc_data_structures::sync::{Lrc, RwLock};
-use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_data_structures::sync::{Lrc, MappedReadGuard};
+use rustc_errors::{
+    Applicability, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, SubdiagnosticMessage,
+};
 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
-use rustc_hir::def::Namespace::*;
-use rustc_hir::def::{self, CtorOf, DefKind, LifetimeRes, PartialRes};
+use rustc_hir::def::Namespace::{self, *};
+use rustc_hir::def::{self, CtorOf, DefKind, DocLinkResMap, LifetimeRes, PartialRes, PerNS};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId};
 use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
-use rustc_hir::definitions::{DefPathData, Definitions};
+use rustc_hir::definitions::DefPathData;
 use rustc_hir::TraitCandidate;
 use rustc_index::vec::IndexVec;
+use rustc_macros::fluent_messages;
 use rustc_metadata::creader::{CStore, CrateLoader};
 use rustc_middle::metadata::ModChild;
 use rustc_middle::middle::privacy::EffectiveVisibilities;
 use rustc_middle::span_bug;
-use rustc_middle::ty::{self, DefIdTree, MainDefinition, RegisteredTools};
+use rustc_middle::ty::{self, DefIdTree, MainDefinition, RegisteredTools, TyCtxt};
 use rustc_middle::ty::{ResolverGlobalCtxt, ResolverOutputs};
 use rustc_query_system::ich::StableHashingContext;
-use rustc_session::cstore::{CrateStore, MetadataLoaderDyn, Untracked};
+use rustc_session::cstore::CrateStore;
 use rustc_session::lint::LintBuffer;
-use rustc_session::Session;
 use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind, SyntaxContext, Transparency};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
@@ -60,7 +60,7 @@ use std::collections::BTreeSet;
 use std::{fmt, ptr};
 
 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
-use imports::{Import, ImportKind, ImportResolver, NameResolution};
+use imports::{Import, ImportKind, NameResolution};
 use late::{HasGenericParams, PathSource, PatternSource};
 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
 
@@ -78,6 +78,9 @@ mod ident;
 mod imports;
 mod late;
 mod macros;
+pub mod rustdoc;
+
+fluent_messages! { "../locales/en-US.ftl" }
 
 enum Weak {
     Yes,
@@ -85,7 +88,7 @@ enum Weak {
 }
 
 #[derive(Copy, Clone, PartialEq, Debug)]
-pub enum Determinacy {
+enum Determinacy {
     Determined,
     Undetermined,
 }
@@ -138,17 +141,17 @@ enum ScopeSet<'a> {
 /// This struct is currently used only for early resolution (imports and macros),
 /// but not for late resolution yet.
 #[derive(Clone, Copy, Debug)]
-pub struct ParentScope<'a> {
-    pub module: Module<'a>,
+struct ParentScope<'a> {
+    module: Module<'a>,
     expansion: LocalExpnId,
-    pub macro_rules: MacroRulesScopeRef<'a>,
+    macro_rules: MacroRulesScopeRef<'a>,
     derives: &'a [ast::Path],
 }
 
 impl<'a> ParentScope<'a> {
     /// Creates a parent scope with the passed argument used as the module scope component,
     /// and other scope components set to default empty values.
-    pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
+    fn module(module: Module<'a>, resolver: &Resolver<'a, '_>) -> ParentScope<'a> {
         ParentScope {
             module,
             expansion: LocalExpnId::ROOT,
@@ -256,7 +259,7 @@ enum VisResolutionError<'a> {
 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
 #[derive(Clone, Copy, Debug)]
-pub struct Segment {
+struct Segment {
     ident: Ident,
     id: Option<NodeId>,
     /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
@@ -379,7 +382,7 @@ impl ModuleOrUniformRoot<'_> {
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 enum PathResult<'a> {
     Module(ModuleOrUniformRoot<'a>),
     NonModule(PartialRes),
@@ -434,7 +437,7 @@ enum ModuleKind {
 
 impl ModuleKind {
     /// Get name of the module.
-    pub fn name(&self) -> Option<Symbol> {
+    fn name(&self) -> Option<Symbol> {
         match self {
             ModuleKind::Block => None,
             ModuleKind::Def(.., name) => Some(*name),
@@ -470,7 +473,7 @@ type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution
 /// * curly-braced block with statements
 ///
 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
-pub struct ModuleData<'a> {
+struct ModuleData<'a> {
     /// The direct parent module (it may not be a `mod`, however).
     parent: Option<Module<'a>>,
     /// What kind of module this is, because this may not be a `mod`.
@@ -529,9 +532,9 @@ impl<'a> ModuleData<'a> {
         }
     }
 
-    fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
+    fn for_each_child<'tcx, R, F>(&'a self, resolver: &mut R, mut f: F)
     where
-        R: AsMut<Resolver<'a>>,
+        R: AsMut<Resolver<'a, 'tcx>>,
         F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
     {
         for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
@@ -542,9 +545,9 @@ impl<'a> ModuleData<'a> {
     }
 
     /// This modifies `self` in place. The traits will be stored in `self.traits`.
-    fn ensure_traits<R>(&'a self, resolver: &mut R)
+    fn ensure_traits<'tcx, R>(&'a self, resolver: &mut R)
     where
-        R: AsMut<Resolver<'a>>,
+        R: AsMut<Resolver<'a, 'tcx>>,
     {
         let mut traits = self.traits.borrow_mut();
         if traits.is_none() {
@@ -569,7 +572,7 @@ impl<'a> ModuleData<'a> {
     }
 
     // Public for rustdoc.
-    pub fn def_id(&self) -> DefId {
+    fn def_id(&self) -> DefId {
         self.opt_def_id().expect("`ModuleData::def_id` is called on a block module")
     }
 
@@ -627,7 +630,7 @@ impl<'a> fmt::Debug for ModuleData<'a> {
 
 /// Records a possibly-private value, type, or module definition.
 #[derive(Clone, Debug)]
-pub struct NameBinding<'a> {
+struct NameBinding<'a> {
     kind: NameBindingKind<'a>,
     ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
     expansion: LocalExpnId,
@@ -635,7 +638,7 @@ pub struct NameBinding<'a> {
     vis: ty::Visibility<DefId>,
 }
 
-pub trait ToNameBinding<'a> {
+trait ToNameBinding<'a> {
     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
 }
 
@@ -839,9 +842,9 @@ impl<'a> NameBinding<'a> {
 }
 
 #[derive(Default, Clone)]
-pub struct ExternPreludeEntry<'a> {
+struct ExternPreludeEntry<'a> {
     extern_crate_item: Option<&'a NameBinding<'a>>,
-    pub introduced_by_item: bool,
+    introduced_by_item: bool,
 }
 
 /// Used for better errors for E0773
@@ -865,8 +868,8 @@ struct MacroData {
 /// The main resolver class.
 ///
 /// This is the visitor that walks the whole crate.
-pub struct Resolver<'a> {
-    session: &'a Session,
+pub struct Resolver<'a, 'tcx> {
+    tcx: TyCtxt<'tcx>,
 
     /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
     expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
@@ -943,23 +946,19 @@ pub struct Resolver<'a> {
     has_pub_restricted: bool,
     used_imports: FxHashSet<NodeId>,
     maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
-    maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
 
     /// Privacy errors are delayed until the end in order to deduplicate them.
     privacy_errors: Vec<PrivacyError<'a>>,
     /// Ambiguity errors are delayed for deduplication.
     ambiguity_errors: Vec<AmbiguityError<'a>>,
     /// `use` injections are delayed for better placement and deduplication.
-    use_injections: Vec<UseError<'a>>,
+    use_injections: Vec<UseError<'tcx>>,
     /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
     macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
 
     arenas: &'a ResolverArenas<'a>,
     dummy_binding: &'a NameBinding<'a>,
 
-    local_crate_name: Symbol,
-    metadata_loader: Box<MetadataLoaderDyn>,
-    untracked: Untracked,
     used_extern_options: FxHashSet<Symbol>,
     macro_names: FxHashSet<Ident>,
     builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
@@ -1046,6 +1045,9 @@ pub struct Resolver<'a> {
     lifetime_elision_allowed: FxHashSet<NodeId>,
 
     effective_visibilities: EffectiveVisibilities,
+    doc_link_resolutions: FxHashMap<LocalDefId, DocLinkResMap>,
+    doc_link_traits_in_scope: FxHashMap<LocalDefId, Vec<DefId>>,
+    all_macro_rules: FxHashMap<Symbol, Res>,
 }
 
 /// Nothing really interesting here; it just provides memory for the rest of the crate.
@@ -1109,42 +1111,25 @@ impl<'a> ResolverArenas<'a> {
     }
 }
 
-impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
-    fn as_mut(&mut self) -> &mut Resolver<'a> {
+impl<'a, 'tcx> AsMut<Resolver<'a, 'tcx>> for Resolver<'a, 'tcx> {
+    fn as_mut(&mut self) -> &mut Resolver<'a, 'tcx> {
         self
     }
 }
 
-/// A minimal subset of resolver that can implemenent `DefIdTree`, sometimes
-/// required to satisfy borrow checker by avoiding borrowing the whole resolver.
-#[derive(Clone, Copy)]
-struct ResolverTree<'a>(&'a Untracked);
-
-impl DefIdTree for ResolverTree<'_> {
-    #[inline]
-    fn opt_parent(self, id: DefId) -> Option<DefId> {
-        let ResolverTree(Untracked { definitions, cstore, .. }) = self;
-        match id.as_local() {
-            Some(id) => definitions.read().def_key(id).parent,
-            None => cstore.as_any().downcast_ref::<CStore>().unwrap().def_key(id).parent,
-        }
-        .map(|index| DefId { index, ..id })
-    }
-}
-
-impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
+impl<'a, 'b, 'tcx> DefIdTree for &'a Resolver<'b, 'tcx> {
     #[inline]
     fn opt_parent(self, id: DefId) -> Option<DefId> {
-        ResolverTree(&self.untracked).opt_parent(id)
+        self.tcx.opt_parent(id)
     }
 }
 
-impl<'a> Resolver<'a> {
+impl<'tcx> Resolver<'_, 'tcx> {
     fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
         self.node_id_to_def_id.get(&node).copied()
     }
 
-    pub fn local_def_id(&self, node: NodeId) -> LocalDefId {
+    fn local_def_id(&self, node: NodeId) -> LocalDefId {
         self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
     }
 
@@ -1162,10 +1147,11 @@ impl<'a> Resolver<'a> {
             "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
             node_id,
             data,
-            self.untracked.definitions.read().def_key(self.node_id_to_def_id[&node_id]),
+            self.tcx.definitions_untracked().def_key(self.node_id_to_def_id[&node_id]),
         );
 
-        let def_id = self.untracked.definitions.write().create_def(parent, data);
+        // FIXME: remove `def_span` body, pass in the right spans here and call `tcx.at().create_def()`
+        let def_id = self.tcx.untracked().definitions.write().create_def(parent, data);
 
         // Create the definition.
         if expn_id != ExpnId::root() {
@@ -1174,7 +1160,7 @@ impl<'a> Resolver<'a> {
 
         // A relative span's parent must be an absolute span.
         debug_assert_eq!(span.data_untracked().parent, None);
-        let _id = self.untracked.source_span.push(span);
+        let _id = self.tcx.untracked().source_span.push(span);
         debug_assert_eq!(_id, def_id);
 
         // Some things for which we allocate `LocalDefId`s don't correspond to
@@ -1193,23 +1179,21 @@ impl<'a> Resolver<'a> {
         if let Some(def_id) = def_id.as_local() {
             self.item_generics_num_lifetimes[&def_id]
         } else {
-            self.cstore().item_generics_num_lifetimes(def_id, self.session)
+            self.cstore().item_generics_num_lifetimes(def_id, self.tcx.sess)
         }
     }
 
-    pub fn sess(&self) -> &'a Session {
-        self.session
+    pub fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
     }
 }
 
-impl<'a> Resolver<'a> {
+impl<'a, 'tcx> Resolver<'a, 'tcx> {
     pub fn new(
-        session: &'a Session,
+        tcx: TyCtxt<'tcx>,
         krate: &Crate,
-        crate_name: Symbol,
-        metadata_loader: Box<MetadataLoaderDyn>,
         arenas: &'a ResolverArenas<'a>,
-    ) -> Resolver<'a> {
+    ) -> Resolver<'a, 'tcx> {
         let root_def_id = CRATE_DEF_ID.to_def_id();
         let mut module_map = FxHashMap::default();
         let graph_root = arenas.new_module(
@@ -1217,7 +1201,7 @@ impl<'a> Resolver<'a> {
             ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
             ExpnId::root(),
             krate.spans.inner_span,
-            session.contains_name(&krate.attrs, sym::no_implicit_prelude),
+            tcx.sess.contains_name(&krate.attrs, sym::no_implicit_prelude),
             &mut module_map,
         );
         let empty_module = arenas.new_module(
@@ -1229,8 +1213,6 @@ impl<'a> Resolver<'a> {
             &mut FxHashMap::default(),
         );
 
-        let definitions = Definitions::new(session.local_stable_crate_id());
-
         let mut visibilities = FxHashMap::default();
         visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
 
@@ -1242,11 +1224,8 @@ impl<'a> Resolver<'a> {
         let mut invocation_parents = FxHashMap::default();
         invocation_parents.insert(LocalExpnId::ROOT, (CRATE_DEF_ID, ImplTraitContext::Existential));
 
-        let mut source_span = IndexVec::default();
-        let _id = source_span.push(krate.spans.inner_span);
-        debug_assert_eq!(_id, CRATE_DEF_ID);
-
-        let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
+        let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = tcx
+            .sess
             .opts
             .externs
             .iter()
@@ -1254,19 +1233,19 @@ impl<'a> Resolver<'a> {
             .map(|(name, _)| (Ident::from_str(name), Default::default()))
             .collect();
 
-        if !session.contains_name(&krate.attrs, sym::no_core) {
+        if !tcx.sess.contains_name(&krate.attrs, sym::no_core) {
             extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
-            if !session.contains_name(&krate.attrs, sym::no_std) {
+            if !tcx.sess.contains_name(&krate.attrs, sym::no_std) {
                 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
             }
         }
 
-        let registered_tools = macros::registered_tools(session, &krate.attrs);
+        let registered_tools = macros::registered_tools(tcx.sess, &krate.attrs);
 
-        let features = session.features_untracked();
+        let features = tcx.sess.features_untracked();
 
         let mut resolver = Resolver {
-            session,
+            tcx,
 
             expn_that_defined: Default::default(),
 
@@ -1304,7 +1283,6 @@ impl<'a> Resolver<'a> {
             has_pub_restricted: false,
             used_imports: FxHashSet::default(),
             maybe_unused_trait_imports: Default::default(),
-            maybe_unused_extern_crates: Vec::new(),
 
             privacy_errors: Vec::new(),
             ambiguity_errors: Vec::new(),
@@ -1320,23 +1298,16 @@ impl<'a> Resolver<'a> {
                 vis: ty::Visibility::Public,
             }),
 
-            metadata_loader,
-            local_crate_name: crate_name,
             used_extern_options: Default::default(),
-            untracked: Untracked {
-                cstore: Box::new(CStore::new(session)),
-                source_span,
-                definitions: RwLock::new(definitions),
-            },
             macro_names: FxHashSet::default(),
             builtin_macros: Default::default(),
             builtin_macro_kinds: Default::default(),
             registered_tools,
             macro_use_prelude: FxHashMap::default(),
             macro_map: FxHashMap::default(),
-            dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
-            dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
-            non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
+            dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(tcx.sess.edition())),
+            dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(tcx.sess.edition())),
+            non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(tcx.sess.edition())),
             invocation_parent_scopes: Default::default(),
             output_macro_rules_scopes: Default::default(),
             macro_rules_scopes: Default::default(),
@@ -1374,6 +1345,9 @@ impl<'a> Resolver<'a> {
             confused_type_with_std_module: Default::default(),
             lifetime_elision_allowed: Default::default(),
             effective_visibilities: Default::default(),
+            doc_link_resolutions: Default::default(),
+            doc_link_traits_in_scope: Default::default(),
+            all_macro_rules: Default::default(),
         };
 
         let root_parent_scope = ParentScope::module(graph_root, &resolver);
@@ -1394,14 +1368,14 @@ impl<'a> Resolver<'a> {
         self.arenas.new_module(parent, kind, expn_id, span, no_implicit_prelude, module_map)
     }
 
-    pub fn next_node_id(&mut self) -> NodeId {
+    fn next_node_id(&mut self) -> NodeId {
         let start = self.next_node_id;
         let next = start.as_u32().checked_add(1).expect("input too large; ran out of NodeIds");
         self.next_node_id = ast::NodeId::from_u32(next);
         start
     }
 
-    pub fn next_node_ids(&mut self, count: usize) -> std::ops::Range<NodeId> {
+    fn next_node_ids(&mut self, count: usize) -> std::ops::Range<NodeId> {
         let start = self.next_node_id;
         let end = start.as_usize().checked_add(count).expect("input too large; ran out of NodeIds");
         self.next_node_id = ast::NodeId::from_usize(end);
@@ -1424,12 +1398,10 @@ impl<'a> Resolver<'a> {
         let extern_crate_map = self.extern_crate_map;
         let reexport_map = self.reexport_map;
         let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
-        let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
         let glob_map = self.glob_map;
         let main_def = self.main_def;
         let confused_type_with_std_module = self.confused_type_with_std_module;
         let effective_visibilities = self.effective_visibilities;
-        let untracked = self.untracked;
         let global_ctxt = ResolverGlobalCtxt {
             expn_that_defined,
             visibilities,
@@ -1439,17 +1411,14 @@ impl<'a> Resolver<'a> {
             reexport_map,
             glob_map,
             maybe_unused_trait_imports,
-            maybe_unused_extern_crates,
-            extern_prelude: self
-                .extern_prelude
-                .iter()
-                .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
-                .collect(),
             main_def,
             trait_impls: self.trait_impls,
             proc_macros,
             confused_type_with_std_module,
             registered_tools: self.registered_tools,
+            doc_link_resolutions: self.doc_link_resolutions,
+            doc_link_traits_in_scope: self.doc_link_traits_in_scope,
+            all_macro_rules: self.all_macro_rules,
         };
         let ast_lowering = ty::ResolverAstLowering {
             legacy_const_generic_args: self.legacy_const_generic_args,
@@ -1465,70 +1434,21 @@ impl<'a> Resolver<'a> {
             builtin_macro_kinds: self.builtin_macro_kinds,
             lifetime_elision_allowed: self.lifetime_elision_allowed,
         };
-        ResolverOutputs { global_ctxt, ast_lowering, untracked }
-    }
-
-    pub fn clone_outputs(&self) -> ResolverOutputs {
-        let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
-        let definitions = self.untracked.definitions.clone();
-        let cstore = Box::new(self.cstore().clone());
-        let untracked =
-            Untracked { cstore, source_span: self.untracked.source_span.clone(), definitions };
-        let global_ctxt = ResolverGlobalCtxt {
-            expn_that_defined: self.expn_that_defined.clone(),
-            visibilities: self.visibilities.clone(),
-            has_pub_restricted: self.has_pub_restricted,
-            extern_crate_map: self.extern_crate_map.clone(),
-            reexport_map: self.reexport_map.clone(),
-            glob_map: self.glob_map.clone(),
-            maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
-            maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
-            extern_prelude: self
-                .extern_prelude
-                .iter()
-                .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
-                .collect(),
-            main_def: self.main_def,
-            trait_impls: self.trait_impls.clone(),
-            proc_macros,
-            confused_type_with_std_module: self.confused_type_with_std_module.clone(),
-            registered_tools: self.registered_tools.clone(),
-            effective_visibilities: self.effective_visibilities.clone(),
-        };
-        let ast_lowering = ty::ResolverAstLowering {
-            legacy_const_generic_args: self.legacy_const_generic_args.clone(),
-            partial_res_map: self.partial_res_map.clone(),
-            import_res_map: self.import_res_map.clone(),
-            label_res_map: self.label_res_map.clone(),
-            lifetimes_res_map: self.lifetimes_res_map.clone(),
-            extra_lifetime_params_map: self.extra_lifetime_params_map.clone(),
-            next_node_id: self.next_node_id,
-            node_id_to_def_id: self.node_id_to_def_id.clone(),
-            def_id_to_node_id: self.def_id_to_node_id.clone(),
-            trait_map: self.trait_map.clone(),
-            builtin_macro_kinds: self.builtin_macro_kinds.clone(),
-            lifetime_elision_allowed: self.lifetime_elision_allowed.clone(),
-        };
-        ResolverOutputs { global_ctxt, ast_lowering, untracked }
+        ResolverOutputs { global_ctxt, ast_lowering }
     }
 
     fn create_stable_hashing_context(&self) -> StableHashingContext<'_> {
-        StableHashingContext::new(self.session, &self.untracked)
+        StableHashingContext::new(self.tcx.sess, self.tcx.untracked())
     }
 
-    pub fn crate_loader(&mut self) -> CrateLoader<'_> {
-        CrateLoader::new(
-            &self.session,
-            &*self.metadata_loader,
-            self.local_crate_name,
-            &mut *self.untracked.cstore.untracked_as_any().downcast_mut().unwrap(),
-            self.untracked.definitions.read(),
-            &mut self.used_extern_options,
-        )
+    fn crate_loader<T>(&mut self, f: impl FnOnce(&mut CrateLoader<'_, '_>) -> T) -> T {
+        let mut cstore = self.tcx.untracked().cstore.write();
+        let cstore = cstore.untracked_as_any().downcast_mut().unwrap();
+        f(&mut CrateLoader::new(self.tcx, &mut *cstore, &mut self.used_extern_options))
     }
 
-    pub fn cstore(&self) -> &CStore {
-        self.untracked.cstore.as_any().downcast_ref().unwrap()
+    fn cstore(&self) -> MappedReadGuard<'_, CStore> {
+        CStore::from_tcx(self.tcx)
     }
 
     fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
@@ -1561,21 +1481,26 @@ impl<'a> Resolver<'a> {
 
     /// Entry point to crate resolution.
     pub fn resolve_crate(&mut self, krate: &Crate) {
-        self.session.time("resolve_crate", || {
-            self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
-            self.session.time("compute_effective_visibilities", || {
+        self.tcx.sess.time("resolve_crate", || {
+            self.tcx.sess.time("finalize_imports", || self.finalize_imports());
+            self.tcx.sess.time("compute_effective_visibilities", || {
                 EffectiveVisibilitiesVisitor::compute_effective_visibilities(self, krate)
             });
-            self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
-            self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
-            self.session.time("resolve_main", || self.resolve_main());
-            self.session.time("resolve_check_unused", || self.check_unused(krate));
-            self.session.time("resolve_report_errors", || self.report_errors(krate));
-            self.session.time("resolve_postprocess", || self.crate_loader().postprocess(krate));
+            self.tcx.sess.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
+            self.tcx.sess.time("late_resolve_crate", || self.late_resolve_crate(krate));
+            self.tcx.sess.time("resolve_main", || self.resolve_main());
+            self.tcx.sess.time("resolve_check_unused", || self.check_unused(krate));
+            self.tcx.sess.time("resolve_report_errors", || self.report_errors(krate));
+            self.tcx
+                .sess
+                .time("resolve_postprocess", || self.crate_loader(|c| c.postprocess(krate)));
         });
+
+        // Make sure we don't mutate the cstore from here on.
+        self.tcx.untracked().cstore.leak();
     }
 
-    pub fn traits_in_scope(
+    fn traits_in_scope(
         &mut self,
         current_trait: Option<Module<'a>>,
         parent_scope: &ParentScope<'a>,
@@ -1911,10 +1836,10 @@ impl<'a> Resolver<'a> {
             } else {
                 let crate_id = if finalize {
                     let Some(crate_id) =
-                        self.crate_loader().process_path_extern(ident.name, ident.span) else { return Some(self.dummy_binding); };
+                        self.crate_loader(|c| c.process_path_extern(ident.name, ident.span)) else { return Some(self.dummy_binding); };
                     crate_id
                 } else {
-                    self.crate_loader().maybe_process_path_extern(ident.name)?
+                    self.crate_loader(|c| c.maybe_process_path_extern(ident.name))?
                 };
                 let crate_root = self.expect_module(crate_id.as_def_id());
                 let vis = ty::Visibility::<LocalDefId>::Public;
@@ -1927,7 +1852,7 @@ impl<'a> Resolver<'a> {
     /// isn't something that can be returned because it can't be made to live that long,
     /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
     /// just that an error occurred.
-    pub fn resolve_rustdoc_path(
+    fn resolve_rustdoc_path(
         &mut self,
         path_str: &str,
         ns: Namespace,
@@ -1959,41 +1884,17 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    /// For rustdoc.
-    /// For local modules returns only reexports, for external modules returns all children.
-    pub fn module_children_or_reexports(&self, def_id: DefId) -> Vec<ModChild> {
-        if let Some(def_id) = def_id.as_local() {
-            self.reexport_map.get(&def_id).cloned().unwrap_or_default()
-        } else {
-            self.cstore().module_children_untracked(def_id, self.session).collect()
-        }
-    }
-
-    /// For rustdoc.
-    pub fn macro_rules_scope(&self, def_id: LocalDefId) -> (MacroRulesScopeRef<'a>, Res) {
-        let scope = *self.macro_rules_scopes.get(&def_id).expect("not a `macro_rules` item");
-        match scope.get() {
-            MacroRulesScope::Binding(mb) => (scope, mb.binding.res()),
-            _ => unreachable!(),
-        }
-    }
-
-    /// For rustdoc.
-    pub fn get_partial_res(&self, node_id: NodeId) -> Option<PartialRes> {
-        self.partial_res_map.get(&node_id).copied()
-    }
-
     /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
     #[inline]
-    pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
-        def_id.as_local().map(|def_id| self.untracked.source_span[def_id])
+    fn opt_span(&self, def_id: DefId) -> Option<Span> {
+        def_id.as_local().map(|def_id| self.tcx.source_span(def_id))
     }
 
     /// Retrieves the name of the given `DefId`.
     #[inline]
-    pub fn opt_name(&self, def_id: DefId) -> Option<Symbol> {
+    fn opt_name(&self, def_id: DefId) -> Option<Symbol> {
         let def_key = match def_id.as_local() {
-            Some(def_id) => self.untracked.definitions.read().def_key(def_id),
+            Some(def_id) => self.tcx.definitions_untracked().def_key(def_id),
             None => self.cstore().def_key(def_id),
         };
         def_key.get_opt_name()
@@ -2002,7 +1903,7 @@ impl<'a> Resolver<'a> {
     /// Checks if an expression refers to a function marked with
     /// `#[rustc_legacy_const_generics]` and returns the argument index list
     /// from the attribute.
-    pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
+    fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
         if let ExprKind::Path(None, path) = &expr.kind {
             // Don't perform legacy const generics rewriting if the path already
             // has generic arguments.
@@ -2025,7 +1926,7 @@ impl<'a> Resolver<'a> {
 
                 let attr = self
                     .cstore()
-                    .item_attrs_untracked(def_id, self.session)
+                    .item_attrs_untracked(def_id, self.tcx.sess)
                     .find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
                 let mut ret = Vec::new();
                 for meta in attr.meta_item_list()? {
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index b5b1602c5..b38c11e8b 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -1,7 +1,6 @@
 //! A bunch of methods and structures more or less related to resolving macros and
 //! interface provided by `Resolver` to macro expander.
 
-use crate::imports::ImportResolver;
 use crate::Namespace::*;
 use crate::{BuiltinMacroState, Determinacy};
 use crate::{DeriveData, Finalize, ParentScope, ResolutionError, Resolver, ScopeSet};
@@ -39,7 +38,7 @@ type Res = def::Res<NodeId>;
 /// Binding produced by a `macro_rules` item.
 /// Not modularized, can shadow previous `macro_rules` bindings, etc.
 #[derive(Debug)]
-pub struct MacroRulesBinding<'a> {
+pub(crate) struct MacroRulesBinding<'a> {
     pub(crate) binding: &'a NameBinding<'a>,
     /// `macro_rules` scope into which the `macro_rules` item was planted.
     pub(crate) parent_macro_rules_scope: MacroRulesScopeRef<'a>,
@@ -52,7 +51,7 @@ pub struct MacroRulesBinding<'a> {
 /// Some macro invocations need to introduce `macro_rules` scopes too because they
 /// can potentially expand into macro definitions.
 #[derive(Copy, Clone, Debug)]
-pub enum MacroRulesScope<'a> {
+pub(crate) enum MacroRulesScope<'a> {
     /// Empty "root" scope at the crate start containing no names.
     Empty,
     /// The scope introduced by a `macro_rules!` macro definition.
@@ -160,7 +159,7 @@ fn soft_custom_inner_attributes_gate(path: &ast::Path, invoc: &Invocation) -> bo
     false
 }
 
-impl<'a> ResolverExpand for Resolver<'a> {
+impl<'a, 'tcx> ResolverExpand for Resolver<'a, 'tcx> {
     fn next_node_id(&mut self) -> NodeId {
         self.next_node_id()
     }
@@ -195,7 +194,8 @@ impl<'a> ResolverExpand for Resolver<'a> {
 
     fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind) {
         if self.builtin_macros.insert(name, BuiltinMacroState::NotYetSeen(ext)).is_some() {
-            self.session
+            self.tcx
+                .sess
                 .diagnostic()
                 .bug(&format!("built-in macro `{}` was already registered", name));
         }
@@ -216,7 +216,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
             ExpnData::allow_unstable(
                 ExpnKind::AstPass(pass),
                 call_site,
-                self.session.edition(),
+                self.tcx.sess.edition(),
                 features.into(),
                 None,
                 parent_module,
@@ -232,7 +232,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
     }
 
     fn resolve_imports(&mut self) {
-        ImportResolver { r: self }.resolve_imports()
+        self.resolve_imports()
     }
 
     fn resolve_macro_invocation(
@@ -430,7 +430,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
                 PathResult::NonModule(..) |
                 // HACK(Urgau): This shouldn't be necessary
                 PathResult::Failed { is_error_from_last_segment: false, .. } => {
-                    self.session
+                    self.tcx.sess
                         .struct_span_err(span, "not sure whether the path is accessible or not")
                         .note("the type may have associated items, but we are currently not checking them")
                         .emit();
@@ -455,7 +455,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
     }
 
     fn get_proc_macro_quoted_span(&self, krate: CrateNum, id: usize) -> Span {
-        self.cstore().get_proc_macro_quoted_span_untracked(krate, id, self.session)
+        self.cstore().get_proc_macro_quoted_span_untracked(krate, id, self.tcx.sess)
     }
 
     fn declare_proc_macro(&mut self, id: NodeId) {
@@ -467,7 +467,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
     }
 }
 
-impl<'a> Resolver<'a> {
+impl<'a, 'tcx> Resolver<'a, 'tcx> {
     /// Resolve macro path with error reporting and recovery.
     /// Uses dummy syntax extensions for unresolved macros or macros with unexpected resolutions
     /// for better error recovery.
@@ -493,10 +493,10 @@ impl<'a> Resolver<'a> {
         // Report errors for the resolved macro.
         for segment in &path.segments {
             if let Some(args) = &segment.args {
-                self.session.span_err(args.span(), "generic arguments in macro path");
+                self.tcx.sess.span_err(args.span(), "generic arguments in macro path");
             }
             if kind == MacroKind::Attr && segment.ident.as_str().starts_with("rustc") {
-                self.session.span_err(
+                self.tcx.sess.span_err(
                     segment.ident.span,
                     "attributes starting with `rustc` are reserved for use by the `rustc` compiler",
                 );
@@ -508,7 +508,7 @@ impl<'a> Resolver<'a> {
                 if let Some(def_id) = def_id.as_local() {
                     self.unused_macros.remove(&def_id);
                     if self.proc_macro_stubs.contains(&def_id) {
-                        self.session.span_err(
+                        self.tcx.sess.span_err(
                             path.span,
                             "can't use a procedural macro from the same crate that defines it",
                         );
@@ -540,7 +540,8 @@ impl<'a> Resolver<'a> {
         if let Some((article, expected)) = unexpected_res {
             let path_str = pprust::path_to_string(path);
             let msg = format!("expected {}, found {} `{}`", expected, res.descr(), path_str);
-            self.session
+            self.tcx
+                .sess
                 .struct_span_err(path.span, &msg)
                 .span_label(path.span, format!("not {} {}", article, expected))
                 .emit();
@@ -550,7 +551,7 @@ impl<'a> Resolver<'a> {
         // We are trying to avoid reporting this error if other related errors were reported.
         if res != Res::Err
             && inner_attr
-            && !self.session.features_untracked().custom_inner_attributes
+            && !self.tcx.sess.features_untracked().custom_inner_attributes
         {
             let msg = match res {
                 Res::Def(..) => "inner macro attributes are unstable",
@@ -558,17 +559,22 @@ impl<'a> Resolver<'a> {
                 _ => unreachable!(),
             };
             if soft_custom_inner_attributes_gate {
-                self.session.parse_sess.buffer_lint(SOFT_UNSTABLE, path.span, node_id, msg);
+                self.tcx.sess.parse_sess.buffer_lint(SOFT_UNSTABLE, path.span, node_id, msg);
             } else {
-                feature_err(&self.session.parse_sess, sym::custom_inner_attributes, path.span, msg)
-                    .emit();
+                feature_err(
+                    &self.tcx.sess.parse_sess,
+                    sym::custom_inner_attributes,
+                    path.span,
+                    msg,
+                )
+                .emit();
             }
         }
 
         Ok((ext, res))
     }
 
-    pub fn resolve_macro_path(
+    pub(crate) fn resolve_macro_path(
         &mut self,
         path: &ast::Path,
         kind: Option<MacroKind>,
@@ -655,7 +661,7 @@ impl<'a> Resolver<'a> {
                     // Make sure compilation does not succeed if preferred macro resolution
                     // has changed after the macro had been expanded. In theory all such
                     // situations should be reported as errors, so this is a bug.
-                    this.session.delay_span_bug(span, "inconsistent resolution for a macro");
+                    this.tcx.sess.delay_span_bug(span, "inconsistent resolution for a macro");
                 }
             } else {
                 // It's possible that the macro was unresolved (indeterminate) and silently
@@ -672,7 +678,7 @@ impl<'a> Resolver<'a> {
                         Segment::names_to_string(path)
                     );
                     let msg_note = "import resolution is stuck, try simplifying macro imports";
-                    this.session.struct_span_err(span, &msg).note(msg_note).emit();
+                    this.tcx.sess.struct_span_err(span, &msg).note(msg_note).emit();
                 }
             }
         };
@@ -699,7 +705,7 @@ impl<'a> Resolver<'a> {
                         // try to suggest if it's not a macro, maybe a function
                         if let PathResult::NonModule(partial_res) = self.maybe_resolve_path(&path, Some(ValueNS), &parent_scope)
                             && partial_res.unresolved_segments() == 0 {
-                            let sm = self.session.source_map();
+                            let sm = self.tcx.sess.source_map();
                             let exclamation_span = sm.next_point(span);
                             suggestion = Some((
                                 vec![(exclamation_span, "".to_string())],
@@ -762,7 +768,7 @@ impl<'a> Resolver<'a> {
                 Err(..) => {
                     let expected = kind.descr_expected();
                     let msg = format!("cannot find {} `{}` in this scope", expected, ident);
-                    let mut err = self.session.struct_span_err(ident.span, &msg);
+                    let mut err = self.tcx.sess.struct_span_err(ident.span, &msg);
                     self.unresolved_macro_suggestions(&mut err, kind, &parent_scope, ident);
                     err.emit();
                 }
@@ -804,7 +810,7 @@ impl<'a> Resolver<'a> {
                     let soft_handler =
                         |lint, span, msg: &_| lint_buffer.buffer_lint(lint, node_id, span, msg);
                     stability::report_unstable(
-                        self.session,
+                        self.tcx.sess,
                         feature,
                         reason.to_opt_reason(),
                         issue,
@@ -840,7 +846,7 @@ impl<'a> Resolver<'a> {
             if kind != NonMacroAttrKind::Tool && binding.map_or(true, |b| b.is_import()) {
                 let msg =
                     format!("cannot use {} {} through an import", kind.article(), kind.descr());
-                let mut err = self.session.struct_span_err(span, &msg);
+                let mut err = self.tcx.sess.struct_span_err(span, &msg);
                 if let Some(binding) = binding {
                     err.span_note(binding.span, &format!("the {} imported here", kind.descr()));
                 }
@@ -855,7 +861,7 @@ impl<'a> Resolver<'a> {
         if ident.name == sym::cfg || ident.name == sym::cfg_attr {
             let macro_kind = self.get_macro(res).map(|macro_data| macro_data.ext.macro_kind());
             if macro_kind.is_some() && sub_namespace_match(macro_kind, Some(MacroKind::Attr)) {
-                self.session.span_err(
+                self.tcx.sess.span_err(
                     ident.span,
                     &format!("name `{}` is reserved in attribute namespace", ident),
                 );
@@ -871,12 +877,7 @@ impl<'a> Resolver<'a> {
         item: &ast::Item,
         edition: Edition,
     ) -> (SyntaxExtension, Vec<(usize, Span)>) {
-        let (mut result, mut rule_spans) = compile_declarative_macro(
-            &self.session,
-            self.session.features_untracked(),
-            item,
-            edition,
-        );
+        let (mut result, mut rule_spans) = compile_declarative_macro(self.tcx.sess, item, edition);
 
         if let Some(builtin_name) = result.builtin_name {
             // The macro was marked with `#[rustc_builtin_macro]`.
@@ -895,7 +896,7 @@ impl<'a> Resolver<'a> {
                     }
                     BuiltinMacroState::AlreadySeen(span) => {
                         struct_span_err!(
-                            self.session,
+                            self.tcx.sess,
                             item.span,
                             E0773,
                             "attempted to define built-in macro more than once"
@@ -906,7 +907,7 @@ impl<'a> Resolver<'a> {
                 }
             } else {
                 let msg = format!("cannot find a built-in macro with name `{}`", item.ident);
-                self.session.span_err(item.span, &msg);
+                self.tcx.sess.span_err(item.span, &msg);
             }
         }
 
diff --git a/compiler/rustc_resolve/src/rustdoc.rs b/compiler/rustc_resolve/src/rustdoc.rs
new file mode 100644
index 000000000..b8853c174
--- /dev/null
+++ b/compiler/rustc_resolve/src/rustdoc.rs
@@ -0,0 +1,388 @@
+use pulldown_cmark::{BrokenLink, Event, LinkType, Options, Parser, Tag};
+use rustc_ast as ast;
+use rustc_ast::util::comments::beautify_doc_string;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_span::def_id::DefId;
+use rustc_span::symbol::{kw, Symbol};
+use rustc_span::Span;
+use std::{cmp, mem};
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum DocFragmentKind {
+    /// A doc fragment created from a `///` or `//!` doc comment.
+    SugaredDoc,
+    /// A doc fragment created from a "raw" `#[doc=""]` attribute.
+    RawDoc,
+}
+
+/// A portion of documentation, extracted from a `#[doc]` attribute.
+///
+/// Each variant contains the line number within the complete doc-comment where the fragment
+/// starts, as well as the Span where the corresponding doc comment or attribute is located.
+///
+/// Included files are kept separate from inline doc comments so that proper line-number
+/// information can be given when a doctest fails. Sugared doc comments and "raw" doc comments are
+/// kept separate because of issue #42760.
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct DocFragment {
+    pub span: Span,
+    /// The module this doc-comment came from.
+    ///
+    /// This allows distinguishing between the original documentation and a pub re-export.
+    /// If it is `None`, the item was not re-exported.
+    pub parent_module: Option<DefId>,
+    pub doc: Symbol,
+    pub kind: DocFragmentKind,
+    pub indent: usize,
+}
+
+#[derive(Clone, Copy, Debug)]
+pub enum MalformedGenerics {
+    /// This link has unbalanced angle brackets.
+    ///
+    /// For example, `Vec<T` should trigger this, as should `Vec<T>>`.
+    UnbalancedAngleBrackets,
+    /// The generics are not attached to a type.
+    ///
+    /// For example, `<T>` should trigger this.
+    ///
+    /// This is detected by checking if the path is empty after the generics are stripped.
+    MissingType,
+    /// The link uses fully-qualified syntax, which is currently unsupported.
+    ///
+    /// For example, `<Vec as IntoIterator>::into_iter` should trigger this.
+    ///
+    /// This is detected by checking if ` as ` (the keyword `as` with spaces around it) is inside
+    /// angle brackets.
+    HasFullyQualifiedSyntax,
+    /// The link has an invalid path separator.
+    ///
+    /// For example, `Vec:<T>:new()` should trigger this. Note that `Vec:new()` will **not**
+    /// trigger this because it has no generics and thus [`strip_generics_from_path`] will not be
+    /// called.
+    ///
+    /// Note that this will also **not** be triggered if the invalid path separator is inside angle
+    /// brackets because rustdoc mostly ignores what's inside angle brackets (except for
+    /// [`HasFullyQualifiedSyntax`](MalformedGenerics::HasFullyQualifiedSyntax)).
+    ///
+    /// This is detected by checking if there is a colon followed by a non-colon in the link.
+    InvalidPathSeparator,
+    /// The link has too many angle brackets.
+    ///
+    /// For example, `Vec<<T>>` should trigger this.
+    TooManyAngleBrackets,
+    /// The link has empty angle brackets.
+    ///
+    /// For example, `Vec<>` should trigger this.
+    EmptyAngleBrackets,
+}
+
+/// Removes excess indentation on comments in order for the Markdown
+/// to be parsed correctly. This is necessary because the convention for
+/// writing documentation is to provide a space between the /// or //! marker
+/// and the doc text, but Markdown is whitespace-sensitive. For example,
+/// a block of text with four-space indentation is parsed as a code block,
+/// so if we didn't unindent comments, these list items
+///
+/// /// A list:
+/// ///
+/// ///    - Foo
+/// ///    - Bar
+///
+/// would be parsed as if they were in a code block, which is likely not what the user intended.
+pub fn unindent_doc_fragments(docs: &mut [DocFragment]) {
+    // `add` is used in case the most common sugared doc syntax is used ("/// "). The other
+    // fragments kind's lines are never starting with a whitespace unless they are using some
+    // markdown formatting requiring it. Therefore, if the doc block have a mix between the two,
+    // we need to take into account the fact that the minimum indent minus one (to take this
+    // whitespace into account).
+    //
+    // For example:
+    //
+    // /// hello!
+    // #[doc = "another"]
+    //
+    // In this case, you want "hello! another" and not "hello!  another".
+    let add = if docs.windows(2).any(|arr| arr[0].kind != arr[1].kind)
+        && docs.iter().any(|d| d.kind == DocFragmentKind::SugaredDoc)
+    {
+        // In case we have a mix of sugared doc comments and "raw" ones, we want the sugared one to
+        // "decide" how much the minimum indent will be.
+        1
+    } else {
+        0
+    };
+
+    // `min_indent` is used to know how much whitespaces from the start of each lines must be
+    // removed. Example:
+    //
+    // ///     hello!
+    // #[doc = "another"]
+    //
+    // In here, the `min_indent` is 1 (because non-sugared fragment are always counted with minimum
+    // 1 whitespace), meaning that "hello!" will be considered a codeblock because it starts with 4
+    // (5 - 1) whitespaces.
+    let Some(min_indent) = docs
+        .iter()
+        .map(|fragment| {
+            fragment.doc.as_str().lines().fold(usize::MAX, |min_indent, line| {
+                if line.chars().all(|c| c.is_whitespace()) {
+                    min_indent
+                } else {
+                    // Compare against either space or tab, ignoring whether they are
+                    // mixed or not.
+                    let whitespace = line.chars().take_while(|c| *c == ' ' || *c == '\t').count();
+                    cmp::min(min_indent, whitespace)
+                        + if fragment.kind == DocFragmentKind::SugaredDoc { 0 } else { add }
+                }
+            })
+        })
+        .min()
+    else {
+        return;
+    };
+
+    for fragment in docs {
+        if fragment.doc == kw::Empty {
+            continue;
+        }
+
+        let min_indent = if fragment.kind != DocFragmentKind::SugaredDoc && min_indent > 0 {
+            min_indent - add
+        } else {
+            min_indent
+        };
+
+        fragment.indent = min_indent;
+    }
+}
+
+/// The goal of this function is to apply the `DocFragment` transformation that is required when
+/// transforming into the final Markdown, which is applying the computed indent to each line in
+/// each doc fragment (a `DocFragment` can contain multiple lines in case of `#[doc = ""]`).
+///
+/// Note: remove the trailing newline where appropriate
+pub fn add_doc_fragment(out: &mut String, frag: &DocFragment) {
+    let s = frag.doc.as_str();
+    let mut iter = s.lines();
+    if s.is_empty() {
+        out.push('\n');
+        return;
+    }
+    while let Some(line) = iter.next() {
+        if line.chars().any(|c| !c.is_whitespace()) {
+            assert!(line.len() >= frag.indent);
+            out.push_str(&line[frag.indent..]);
+        } else {
+            out.push_str(line);
+        }
+        out.push('\n');
+    }
+}
+
+pub fn attrs_to_doc_fragments<'a>(
+    attrs: impl Iterator<Item = (&'a ast::Attribute, Option<DefId>)>,
+    doc_only: bool,
+) -> (Vec<DocFragment>, ast::AttrVec) {
+    let mut doc_fragments = Vec::new();
+    let mut other_attrs = ast::AttrVec::new();
+    for (attr, parent_module) in attrs {
+        if let Some((doc_str, comment_kind)) = attr.doc_str_and_comment_kind() {
+            let doc = beautify_doc_string(doc_str, comment_kind);
+            let kind = if attr.is_doc_comment() {
+                DocFragmentKind::SugaredDoc
+            } else {
+                DocFragmentKind::RawDoc
+            };
+            let fragment = DocFragment { span: attr.span, doc, kind, parent_module, indent: 0 };
+            doc_fragments.push(fragment);
+        } else if !doc_only {
+            other_attrs.push(attr.clone());
+        }
+    }
+
+    unindent_doc_fragments(&mut doc_fragments);
+
+    (doc_fragments, other_attrs)
+}
+
+/// Return the doc-comments on this item, grouped by the module they came from.
+/// The module can be different if this is a re-export with added documentation.
+///
+/// The last newline is not trimmed so the produced strings are reusable between
+/// early and late doc link resolution regardless of their position.
+pub fn prepare_to_doc_link_resolution(
+    doc_fragments: &[DocFragment],
+) -> FxHashMap<Option<DefId>, String> {
+    let mut res = FxHashMap::default();
+    for fragment in doc_fragments {
+        let out_str = res.entry(fragment.parent_module).or_default();
+        add_doc_fragment(out_str, fragment);
+    }
+    res
+}
+
+/// Options for rendering Markdown in the main body of documentation.
+pub fn main_body_opts() -> Options {
+    Options::ENABLE_TABLES
+        | Options::ENABLE_FOOTNOTES
+        | Options::ENABLE_STRIKETHROUGH
+        | Options::ENABLE_TASKLISTS
+        | Options::ENABLE_SMART_PUNCTUATION
+}
+
+fn strip_generics_from_path_segment(segment: Vec<char>) -> Result<String, MalformedGenerics> {
+    let mut stripped_segment = String::new();
+    let mut param_depth = 0;
+
+    let mut latest_generics_chunk = String::new();
+
+    for c in segment {
+        if c == '<' {
+            param_depth += 1;
+            latest_generics_chunk.clear();
+        } else if c == '>' {
+            param_depth -= 1;
+            if latest_generics_chunk.contains(" as ") {
+                // The segment tries to use fully-qualified syntax, which is currently unsupported.
+                // Give a helpful error message instead of completely ignoring the angle brackets.
+                return Err(MalformedGenerics::HasFullyQualifiedSyntax);
+            }
+        } else {
+            if param_depth == 0 {
+                stripped_segment.push(c);
+            } else {
+                latest_generics_chunk.push(c);
+            }
+        }
+    }
+
+    if param_depth == 0 {
+        Ok(stripped_segment)
+    } else {
+        // The segment has unbalanced angle brackets, e.g. `Vec<T` or `Vec<T>>`
+        Err(MalformedGenerics::UnbalancedAngleBrackets)
+    }
+}
+
+pub fn strip_generics_from_path(path_str: &str) -> Result<Box<str>, MalformedGenerics> {
+    if !path_str.contains(['<', '>']) {
+        return Ok(path_str.into());
+    }
+    let mut stripped_segments = vec![];
+    let mut path = path_str.chars().peekable();
+    let mut segment = Vec::new();
+
+    while let Some(chr) = path.next() {
+        match chr {
+            ':' => {
+                if path.next_if_eq(&':').is_some() {
+                    let stripped_segment =
+                        strip_generics_from_path_segment(mem::take(&mut segment))?;
+                    if !stripped_segment.is_empty() {
+                        stripped_segments.push(stripped_segment);
+                    }
+                } else {
+                    return Err(MalformedGenerics::InvalidPathSeparator);
+                }
+            }
+            '<' => {
+                segment.push(chr);
+
+                match path.next() {
+                    Some('<') => {
+                        return Err(MalformedGenerics::TooManyAngleBrackets);
+                    }
+                    Some('>') => {
+                        return Err(MalformedGenerics::EmptyAngleBrackets);
+                    }
+                    Some(chr) => {
+                        segment.push(chr);
+
+                        while let Some(chr) = path.next_if(|c| *c != '>') {
+                            segment.push(chr);
+                        }
+                    }
+                    None => break,
+                }
+            }
+            _ => segment.push(chr),
+        }
+        trace!("raw segment: {:?}", segment);
+    }
+
+    if !segment.is_empty() {
+        let stripped_segment = strip_generics_from_path_segment(segment)?;
+        if !stripped_segment.is_empty() {
+            stripped_segments.push(stripped_segment);
+        }
+    }
+
+    debug!("path_str: {:?}\nstripped segments: {:?}", path_str, &stripped_segments);
+
+    let stripped_path = stripped_segments.join("::");
+
+    if !stripped_path.is_empty() {
+        Ok(stripped_path.into())
+    } else {
+        Err(MalformedGenerics::MissingType)
+    }
+}
+
+/// Returns whether the first doc-comment is an inner attribute.
+///
+//// If there are no doc-comments, return true.
+/// FIXME(#78591): Support both inner and outer attributes on the same item.
+pub fn inner_docs(attrs: &[ast::Attribute]) -> bool {
+    attrs.iter().find(|a| a.doc_str().is_some()).map_or(true, |a| a.style == ast::AttrStyle::Inner)
+}
+
+/// Simplified version of the corresponding function in rustdoc.
+/// If the rustdoc version returns a successful result, this function must return the same result.
+/// Otherwise this function may return anything.
+fn preprocess_link(link: &str) -> Box<str> {
+    let link = link.replace('`', "");
+    let link = link.split('#').next().unwrap();
+    let link = link.trim();
+    let link = link.rsplit('@').next().unwrap();
+    let link = link.strip_suffix("()").unwrap_or(link);
+    let link = link.strip_suffix("{}").unwrap_or(link);
+    let link = link.strip_suffix("[]").unwrap_or(link);
+    let link = if link != "!" { link.strip_suffix('!').unwrap_or(link) } else { link };
+    strip_generics_from_path(link).unwrap_or_else(|_| link.into())
+}
+
+/// Keep inline and reference links `[]`,
+/// but skip autolinks `<>` which we never consider to be intra-doc links.
+pub fn may_be_doc_link(link_type: LinkType) -> bool {
+    match link_type {
+        LinkType::Inline
+        | LinkType::Reference
+        | LinkType::ReferenceUnknown
+        | LinkType::Collapsed
+        | LinkType::CollapsedUnknown
+        | LinkType::Shortcut
+        | LinkType::ShortcutUnknown => true,
+        LinkType::Autolink | LinkType::Email => false,
+    }
+}
+
+/// Simplified version of `preprocessed_markdown_links` from rustdoc.
+/// Must return at least the same links as it, but may add some more links on top of that.
+pub(crate) fn attrs_to_preprocessed_links(attrs: &[ast::Attribute]) -> Vec<Box<str>> {
+    let (doc_fragments, _) = attrs_to_doc_fragments(attrs.iter().map(|attr| (attr, None)), true);
+    let doc = prepare_to_doc_link_resolution(&doc_fragments).into_values().next().unwrap();
+
+    Parser::new_with_broken_link_callback(
+        &doc,
+        main_body_opts(),
+        Some(&mut |link: BrokenLink<'_>| Some((link.reference, "".into()))),
+    )
+    .filter_map(|event| match event {
+        Event::Start(Tag::Link(link_type, dest, _)) if may_be_doc_link(link_type) => {
+            Some(preprocess_link(&dest))
+        }
+        _ => None,
+    })
+    .collect()
+}