Rollup merge of #69989 - petrochenkov:nolegacy, r=eddyb,matthewjasper

resolve/hygiene: `macro_rules` are not "legacy"

The "modern" vs "legacy" naming was introduced by jseyfried during initial implementation of macros 2.0.
At this point it's clear that `macro_rules` are not going anywhere and won't be deprecated in the near future.
So this PR changes the naming "legacy" (when it implies "macro_rules") to "macro_rules".
This should also help people reading this code because it's wasn't obvious that "legacy" actually meant "macro_rules" in these contexts.

The most contentious renaming here is probably
```
fn modern -> fn normalize_to_macros_2_0
fn modern_and_legacy -> fn normalize_to_macro_rules
```
Other alternatives that I could think of are `normalize_to_opaque`/`normalize_to_semitransparent`, or `strip_non_opaque`/`strip_transparent`, but they seemed less intuitive.
The documentation to these functions can be found in `symbol.rs`.

r? @matthewjasper

src/librustc/ty/mod.rs

@@ -3083,7 +3083,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
         // We could use `Ident::eq` here, but we deliberately don't. The name
         // comparison fails frequently, and we want to avoid the expensive
-        // `modern()` calls required for the span comparison whenever possible.
+        // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
         use_name.name == def_name.name
             && use_name
                 .span
@@ -3099,7 +3099,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
-        ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
+        ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope));
         ident
     }
 
@@ -3109,12 +3109,14 @@ impl<'tcx> TyCtxt<'tcx> {
         scope: DefId,
         block: hir::HirId,
     ) -> (Ident, DefId) {
-        let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
+        let scope =
-            Some(actual_expansion) => {
+            match ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope))
-                self.hir().definitions().parent_module_of_macro_def(actual_expansion)
+            {
-            }
+                Some(actual_expansion) => {
-            None => self.parent_module(block),
+                    self.hir().definitions().parent_module_of_macro_def(actual_expansion)
-        };
+                }
+                None => self.parent_module(block),
+            };
         (ident, scope)
     }
 

src/librustc_ast/ast.rs

@@ -1450,7 +1450,7 @@ impl MacDelimiter {
 pub struct MacroDef {
     pub body: P<MacArgs>,
     /// `true` if macro was defined with `macro_rules`.
-    pub legacy: bool,
+    pub macro_rules: bool,
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy, Hash, Eq, PartialEq)]

src/librustc_ast/mut_visit.rs

@@ -591,7 +591,7 @@ pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
 }
 
 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
-    let MacroDef { body, legacy: _ } = macro_def;
+    let MacroDef { body, macro_rules: _ } = macro_def;
     visit_mac_args(body, vis);
 }
 

src/librustc_ast_lowering/item.rs

@@ -115,7 +115,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             _ => &[],
         };
         let lt_def_names = parent_generics.iter().filter_map(|param| match param.kind {
-            hir::GenericParamKind::Lifetime { .. } => Some(param.name.modern()),
+            hir::GenericParamKind::Lifetime { .. } => Some(param.name.normalize_to_macros_2_0()),
             _ => None,
         });
         self.in_scope_lifetimes.extend(lt_def_names);
@@ -220,8 +220,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let mut vis = self.lower_visibility(&i.vis, None);
         let attrs = self.lower_attrs(&i.attrs);
 
-        if let ItemKind::MacroDef(MacroDef { ref body, legacy }) = i.kind {
+        if let ItemKind::MacroDef(MacroDef { ref body, macro_rules }) = i.kind {
-            if !legacy || attr::contains_name(&i.attrs, sym::macro_export) {
+            if !macro_rules || attr::contains_name(&i.attrs, sym::macro_export) {
                 let hir_id = self.lower_node_id(i.id);
                 let body = P(self.lower_mac_args(body));
                 self.exported_macros.push(hir::MacroDef {
@@ -230,7 +230,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     attrs,
                     hir_id,
                     span: i.span,
-                    ast: MacroDef { body, legacy },
+                    ast: MacroDef { body, macro_rules },
                 });
             } else {
                 self.non_exported_macro_attrs.extend(attrs.iter().cloned());

src/librustc_ast_lowering/lib.rs

@@ -153,7 +153,7 @@ struct LoweringContext<'a, 'hir: 'a> {
     /// against this list to see if it is already in-scope, or if a definition
     /// needs to be created for it.
     ///
-    /// We always store a `modern()` version of the param-name in this
+    /// We always store a `normalize_to_macros_2_0()` version of the param-name in this
     /// vector.
     in_scope_lifetimes: Vec<ParamName>,
 
@@ -803,14 +803,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             return;
         }
 
-        if self.in_scope_lifetimes.contains(&ParamName::Plain(ident.modern())) {
+        if self.in_scope_lifetimes.contains(&ParamName::Plain(ident.normalize_to_macros_2_0())) {
             return;
         }
 
         let hir_name = ParamName::Plain(ident);
 
-        if self.lifetimes_to_define.iter().any(|(_, lt_name)| lt_name.modern() == hir_name.modern())
+        if self.lifetimes_to_define.iter().any(|(_, lt_name)| {
-        {
+            lt_name.normalize_to_macros_2_0() == hir_name.normalize_to_macros_2_0()
+        }) {
             return;
         }
 
@@ -838,7 +839,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     ) -> T {
         let old_len = self.in_scope_lifetimes.len();
         let lt_def_names = params.iter().filter_map(|param| match param.kind {
-            GenericParamKind::Lifetime { .. } => Some(ParamName::Plain(param.ident.modern())),
+            GenericParamKind::Lifetime { .. } => {
+                Some(ParamName::Plain(param.ident.normalize_to_macros_2_0()))
+            }
             _ => None,
         });
         self.in_scope_lifetimes.extend(lt_def_names);

src/librustc_ast_passes/feature_gate.rs

@@ -366,7 +366,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 gate_feature_post!(&self, trait_alias, i.span, "trait aliases are experimental");
             }
 
-            ast::ItemKind::MacroDef(ast::MacroDef { legacy: false, .. }) => {
+            ast::ItemKind::MacroDef(ast::MacroDef { macro_rules: false, .. }) => {
                 let msg = "`macro` is experimental";
                 gate_feature_post!(&self, decl_macro, i.span, msg);
             }

src/librustc_ast_pretty/pprust.rs

@@ -1238,7 +1238,7 @@ impl<'a> State<'a> {
                 }
             }
             ast::ItemKind::MacroDef(ref macro_def) => {
-                let (kw, has_bang) = if macro_def.legacy {
+                let (kw, has_bang) = if macro_def.macro_rules {
                     ("macro_rules", true)
                 } else {
                     self.print_visibility(&item.vis);

src/librustc_attr/builtin.rs

@@ -1024,7 +1024,7 @@ pub enum TransparencyError {
 
 pub fn find_transparency(
     attrs: &[Attribute],
-    is_legacy: bool,
+    macro_rules: bool,
 ) -> (Transparency, Option<TransparencyError>) {
     let mut transparency = None;
     let mut error = None;
@@ -1049,7 +1049,7 @@ pub fn find_transparency(
             }
         }
     }
-    let fallback = if is_legacy { Transparency::SemiTransparent } else { Transparency::Opaque };
+    let fallback = if macro_rules { Transparency::SemiTransparent } else { Transparency::Opaque };
     (transparency.map_or(fallback, |t| t.0), error)
 }
 

src/librustc_expand/mbe/macro_check.rs

@@ -419,10 +419,10 @@ fn check_nested_occurrences(
             | (NestedMacroState::MacroName, &TokenTree::Delimited(_, ref del))
                 if del.delim == DelimToken::Brace =>
             {
-                let legacy = state == NestedMacroState::MacroRulesNotName;
+                let macro_rules = state == NestedMacroState::MacroRulesNotName;
                 state = NestedMacroState::Empty;
                 let rest =
-                    check_nested_macro(sess, node_id, legacy, &del.tts, &nested_macros, valid);
+                    check_nested_macro(sess, node_id, macro_rules, &del.tts, &nested_macros, valid);
                 // If we did not check the whole macro definition, then check the rest as if outside
                 // the macro definition.
                 check_nested_occurrences(
@@ -493,21 +493,21 @@ fn check_nested_occurrences(
 /// Arguments:
 /// - `sess` is used to emit diagnostics and lints
 /// - `node_id` is used to emit lints
-/// - `legacy` specifies whether the macro is legacy
+/// - `macro_rules` specifies whether the macro is `macro_rules`
 /// - `tts` is checked as a list of (LHS) => {RHS}
 /// - `macros` is the stack of outer macros
 /// - `valid` is set in case of errors
 fn check_nested_macro(
     sess: &ParseSess,
     node_id: NodeId,
-    legacy: bool,
+    macro_rules: bool,
     tts: &[TokenTree],
     macros: &Stack<'_, MacroState<'_>>,
     valid: &mut bool,
 ) -> usize {
     let n = tts.len();
     let mut i = 0;
-    let separator = if legacy { TokenKind::Semi } else { TokenKind::Comma };
+    let separator = if macro_rules { TokenKind::Semi } else { TokenKind::Comma };
     loop {
         // We expect 3 token trees: `(LHS) => {RHS}`. The separator is checked after.
         if i + 2 >= n
@@ -522,7 +522,7 @@ fn check_nested_macro(
         let mut binders = Binders::default();
         check_binders(sess, node_id, lhs, macros, &mut binders, &Stack::Empty, valid);
         check_occurrences(sess, node_id, rhs, macros, &binders, &Stack::Empty, valid);
-        // Since the last semicolon is optional for legacy macros and decl_macro are not terminated,
+        // Since the last semicolon is optional for `macro_rules` macros and decl_macro are not terminated,
         // we increment our checked position by how many token trees we already checked (the 3
         // above) before checking for the separator.
         i += 3;

src/librustc_expand/mbe/macro_rules.rs

@@ -350,8 +350,8 @@ pub fn compile_declarative_macro(
     let tt_spec = ast::Ident::new(sym::tt, def.span);
 
     // Parse the macro_rules! invocation
-    let (is_legacy, body) = match &def.kind {
+    let (macro_rules, body) = match &def.kind {
-        ast::ItemKind::MacroDef(macro_def) => (macro_def.legacy, macro_def.body.inner_tokens()),
+        ast::ItemKind::MacroDef(def) => (def.macro_rules, def.body.inner_tokens()),
         _ => unreachable!(),
     };
 
@@ -370,7 +370,7 @@ pub fn compile_declarative_macro(
                     mbe::TokenTree::MetaVarDecl(def.span, rhs_nm, tt_spec),
                 ],
                 separator: Some(Token::new(
-                    if is_legacy { token::Semi } else { token::Comma },
+                    if macro_rules { token::Semi } else { token::Comma },
                     def.span,
                 )),
                 kleene: mbe::KleeneToken::new(mbe::KleeneOp::OneOrMore, def.span),
@@ -382,7 +382,7 @@ pub fn compile_declarative_macro(
             DelimSpan::dummy(),
             Lrc::new(mbe::SequenceRepetition {
                 tts: vec![mbe::TokenTree::token(
-                    if is_legacy { token::Semi } else { token::Comma },
+                    if macro_rules { token::Semi } else { token::Comma },
                     def.span,
                 )],
                 separator: None,
@@ -456,7 +456,7 @@ pub fn compile_declarative_macro(
     // that is not lint-checked and trigger the "failed to process buffered lint here" bug.
     valid &= macro_check::check_meta_variables(sess, ast::CRATE_NODE_ID, def.span, &lhses, &rhses);
 
-    let (transparency, transparency_error) = attr::find_transparency(&def.attrs, is_legacy);
+    let (transparency, transparency_error) = attr::find_transparency(&def.attrs, macro_rules);
     match transparency_error {
         Some(TransparencyError::UnknownTransparency(value, span)) => {
             diag.span_err(span, &format!("unknown macro transparency: `{}`", value))

src/librustc_hir/hir.rs

@@ -79,9 +79,9 @@ impl ParamName {
         }
     }
 
-    pub fn modern(&self) -> ParamName {
+    pub fn normalize_to_macros_2_0(&self) -> ParamName {
         match *self {
-            ParamName::Plain(ident) => ParamName::Plain(ident.modern()),
+            ParamName::Plain(ident) => ParamName::Plain(ident.normalize_to_macros_2_0()),
             param_name => param_name,
         }
     }
@@ -151,9 +151,11 @@ impl LifetimeName {
         self == &LifetimeName::Static
     }
 
-    pub fn modern(&self) -> LifetimeName {
+    pub fn normalize_to_macros_2_0(&self) -> LifetimeName {
         match *self {
-            LifetimeName::Param(param_name) => LifetimeName::Param(param_name.modern()),
+            LifetimeName::Param(param_name) => {
+                LifetimeName::Param(param_name.normalize_to_macros_2_0())
+            }
             lifetime_name => lifetime_name,
         }
     }

src/librustc_mir/monomorphize/collector.rs

@@ -1088,9 +1088,9 @@ fn create_mono_items_for_default_impls<'tcx>(
                 let param_env = ty::ParamEnv::reveal_all();
                 let trait_ref = tcx.normalize_erasing_regions(param_env, trait_ref);
                 let overridden_methods: FxHashSet<_> =
-                    items.iter().map(|iiref| iiref.ident.modern()).collect();
+                    items.iter().map(|iiref| iiref.ident.normalize_to_macros_2_0()).collect();
                 for method in tcx.provided_trait_methods(trait_ref.def_id) {
-                    if overridden_methods.contains(&method.ident.modern()) {
+                    if overridden_methods.contains(&method.ident.normalize_to_macros_2_0()) {
                         continue;
                     }
 

src/librustc_parse/parser/item.rs

@@ -1260,7 +1260,7 @@ impl<'a> Parser<'a> {
         };
 
         self.sess.gated_spans.gate(sym::decl_macro, lo.to(self.prev_token.span));
-        Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, legacy: false })))
+        Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, macro_rules: false })))
     }
 
     /// Is this unambiguously the start of a `macro_rules! foo` item defnition?
@@ -1270,7 +1270,7 @@ impl<'a> Parser<'a> {
             && self.look_ahead(2, |t| t.is_ident())
     }
 
-    /// Parses a legacy `macro_rules! foo { ... }` declarative macro.
+    /// Parses a `macro_rules! foo { ... }` declarative macro.
     fn parse_item_macro_rules(&mut self, vis: &Visibility) -> PResult<'a, ItemInfo> {
         self.expect_keyword(kw::MacroRules)?; // `macro_rules`
         self.expect(&token::Not)?; // `!`
@@ -1280,7 +1280,7 @@ impl<'a> Parser<'a> {
         self.eat_semi_for_macro_if_needed(&body);
         self.complain_if_pub_macro(vis, true);
 
-        Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, legacy: true })))
+        Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, macro_rules: true })))
     }
 
     /// Item macro invocations or `macro_rules!` definitions need inherited visibility.

src/librustc_privacy/lib.rs

@@ -920,7 +920,7 @@ impl Visitor<'tcx> for EmbargoVisitor<'tcx> {
     }
 
     fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef<'tcx>) {
-        if attr::find_transparency(&md.attrs, md.ast.legacy).0 != Transparency::Opaque {
+        if attr::find_transparency(&md.attrs, md.ast.macro_rules).0 != Transparency::Opaque {
             self.update(md.hir_id, Some(AccessLevel::Public));
             return;
         }

src/librustc_resolve/build_reduced_graph.rs

@@ -7,7 +7,7 @@
 
 use crate::def_collector::collect_definitions;
 use crate::imports::{Import, ImportKind};
-use crate::macros::{LegacyBinding, LegacyScope};
+use crate::macros::{MacroRulesBinding, MacroRulesScope};
 use crate::Namespace::{self, MacroNS, TypeNS, ValueNS};
 use crate::{CrateLint, Determinacy, PathResult, ResolutionError, VisResolutionError};
 use crate::{
@@ -165,11 +165,11 @@ impl<'a> Resolver<'a> {
         &mut self,
         fragment: &AstFragment,
         parent_scope: ParentScope<'a>,
-    ) -> LegacyScope<'a> {
+    ) -> MacroRulesScope<'a> {
         collect_definitions(&mut self.definitions, fragment, parent_scope.expansion);
         let mut visitor = BuildReducedGraphVisitor { r: self, parent_scope };
         fragment.visit_with(&mut visitor);
-        visitor.parent_scope.legacy
+        visitor.parent_scope.macro_rules
     }
 
     crate fn build_reduced_graph_external(&mut self, module: Module<'a>) {
@@ -624,7 +624,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     self.r.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX })
                 };
 
-                let used = self.process_legacy_macro_imports(item, module);
+                let used = self.process_macro_use_imports(item, module);
                 let binding =
                     (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.r.arenas);
                 let import = self.r.arenas.alloc_import(Import {
@@ -645,7 +645,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 self.r.potentially_unused_imports.push(import);
                 let imported_binding = self.r.import(binding, import);
                 if ptr::eq(parent, self.r.graph_root) {
-                    if let Some(entry) = self.r.extern_prelude.get(&ident.modern()) {
+                    if let Some(entry) = self.r.extern_prelude.get(&ident.normalize_to_macros_2_0())
+                    {
                         if expansion != ExpnId::root()
                             && orig_name.is_some()
                             && entry.extern_crate_item.is_none()
@@ -656,10 +657,12 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         }
                     }
                     let entry =
-                        self.r.extern_prelude.entry(ident.modern()).or_insert(ExternPreludeEntry {
+                        self.r.extern_prelude.entry(ident.normalize_to_macros_2_0()).or_insert(
-                            extern_crate_item: None,
+                            ExternPreludeEntry {
-                            introduced_by_item: true,
+                                extern_crate_item: None,
-                        });
+                                introduced_by_item: true,
+                            },
+                        );
                     entry.extern_crate_item = Some(imported_binding);
                     if orig_name.is_some() {
                         entry.introduced_by_item = true;
@@ -913,7 +916,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         }
     }
 
-    fn legacy_import_macro(
+    fn add_macro_use_binding(
         &mut self,
         name: ast::Name,
         binding: &'a NameBinding<'a>,
@@ -929,7 +932,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
     }
 
     /// Returns `true` if we should consider the underlying `extern crate` to be used.
-    fn process_legacy_macro_imports(&mut self, item: &Item, module: Module<'a>) -> bool {
+    fn process_macro_use_imports(&mut self, item: &Item, module: Module<'a>) -> bool {
         let mut import_all = None;
         let mut single_imports = Vec::new();
         for attr in &item.attrs {
@@ -1004,7 +1007,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             module.for_each_child(self, |this, ident, ns, binding| {
                 if ns == MacroNS {
                     let imported_binding = this.r.import(binding, import);
-                    this.legacy_import_macro(ident.name, imported_binding, span, allow_shadowing);
+                    this.add_macro_use_binding(ident.name, imported_binding, span, allow_shadowing);
                 }
             });
         } else {
@@ -1021,7 +1024,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     let import = macro_use_import(self, ident.span);
                     self.r.potentially_unused_imports.push(import);
                     let imported_binding = self.r.import(binding, import);
-                    self.legacy_import_macro(
+                    self.add_macro_use_binding(
                         ident.name,
                         imported_binding,
                         ident.span,
@@ -1060,7 +1063,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         false
     }
 
-    fn visit_invoc(&mut self, id: NodeId) -> LegacyScope<'a> {
+    fn visit_invoc(&mut self, id: NodeId) -> MacroRulesScope<'a> {
         let invoc_id = id.placeholder_to_expn_id();
 
         self.parent_scope.module.unexpanded_invocations.borrow_mut().insert(invoc_id);
@@ -1068,7 +1071,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         let old_parent_scope = self.r.invocation_parent_scopes.insert(invoc_id, self.parent_scope);
         assert!(old_parent_scope.is_none(), "invocation data is reset for an invocation");
 
-        LegacyScope::Invocation(invoc_id)
+        MacroRulesScope::Invocation(invoc_id)
     }
 
     fn proc_macro_stub(item: &ast::Item) -> Option<(MacroKind, Ident, Span)> {
@@ -1095,20 +1098,20 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         }
     }
 
-    fn define_macro(&mut self, item: &ast::Item) -> LegacyScope<'a> {
+    fn define_macro(&mut self, item: &ast::Item) -> MacroRulesScope<'a> {
         let parent_scope = self.parent_scope;
         let expansion = parent_scope.expansion;
-        let (ext, ident, span, is_legacy) = match &item.kind {
+        let (ext, ident, span, macro_rules) = match &item.kind {
             ItemKind::MacroDef(def) => {
                 let ext = Lrc::new(self.r.compile_macro(item, self.r.session.edition()));
-                (ext, item.ident, item.span, def.legacy)
+                (ext, item.ident, item.span, def.macro_rules)
             }
             ItemKind::Fn(..) => match Self::proc_macro_stub(item) {
                 Some((macro_kind, ident, span)) => {
                     self.r.proc_macro_stubs.insert(item.id);
                     (self.r.dummy_ext(macro_kind), ident, span, false)
                 }
-                None => return parent_scope.legacy,
+                None => return parent_scope.macro_rules,
             },
             _ => unreachable!(),
         };
@@ -1118,8 +1121,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         self.r.macro_map.insert(def_id, ext);
         self.r.local_macro_def_scopes.insert(item.id, parent_scope.module);
 
-        if is_legacy {
+        if macro_rules {
-            let ident = ident.modern();
+            let ident = ident.normalize_to_macros_2_0();
             self.r.macro_names.insert(ident);
             let is_macro_export = attr::contains_name(&item.attrs, sym::macro_export);
             let vis = if is_macro_export {
@@ -1137,8 +1140,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 self.r.check_reserved_macro_name(ident, res);
                 self.insert_unused_macro(ident, item.id, span);
             }
-            LegacyScope::Binding(self.r.arenas.alloc_legacy_binding(LegacyBinding {
+            MacroRulesScope::Binding(self.r.arenas.alloc_macro_rules_binding(MacroRulesBinding {
-                parent_legacy_scope: parent_scope.legacy,
+                parent_macro_rules_scope: parent_scope.macro_rules,
                 binding,
                 ident,
             }))
@@ -1149,7 +1152,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 self.insert_unused_macro(ident, item.id, span);
             }
             self.r.define(module, ident, MacroNS, (res, vis, span, expansion));
-            self.parent_scope.legacy
+            self.parent_scope.macro_rules
         }
     }
 }
@@ -1174,29 +1177,29 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
     fn visit_item(&mut self, item: &'b Item) {
         let macro_use = match item.kind {
             ItemKind::MacroDef(..) => {
-                self.parent_scope.legacy = self.define_macro(item);
+                self.parent_scope.macro_rules = self.define_macro(item);
                 return;
             }
             ItemKind::MacCall(..) => {
-                self.parent_scope.legacy = self.visit_invoc(item.id);
+                self.parent_scope.macro_rules = self.visit_invoc(item.id);
                 return;
             }
             ItemKind::Mod(..) => self.contains_macro_use(&item.attrs),
             _ => false,
         };
         let orig_current_module = self.parent_scope.module;
-        let orig_current_legacy_scope = self.parent_scope.legacy;
+        let orig_current_macro_rules_scope = self.parent_scope.macro_rules;
         self.build_reduced_graph_for_item(item);
         visit::walk_item(self, item);
         self.parent_scope.module = orig_current_module;
         if !macro_use {
-            self.parent_scope.legacy = orig_current_legacy_scope;
+            self.parent_scope.macro_rules = orig_current_macro_rules_scope;
         }
     }
 
     fn visit_stmt(&mut self, stmt: &'b ast::Stmt) {
         if let ast::StmtKind::MacCall(..) = stmt.kind {
-            self.parent_scope.legacy = self.visit_invoc(stmt.id);
+            self.parent_scope.macro_rules = self.visit_invoc(stmt.id);
         } else {
             visit::walk_stmt(self, stmt);
         }
@@ -1214,11 +1217,11 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
 
     fn visit_block(&mut self, block: &'b Block) {
         let orig_current_module = self.parent_scope.module;
-        let orig_current_legacy_scope = self.parent_scope.legacy;
+        let orig_current_macro_rules_scope = self.parent_scope.macro_rules;
         self.build_reduced_graph_for_block(block);
         visit::walk_block(self, block);
         self.parent_scope.module = orig_current_module;
-        self.parent_scope.legacy = orig_current_legacy_scope;
+        self.parent_scope.macro_rules = orig_current_macro_rules_scope;
     }
 
     fn visit_assoc_item(&mut self, item: &'b AssocItem, ctxt: AssocCtxt) {

src/librustc_resolve/diagnostics.rs

@@ -21,7 +21,9 @@ use rustc_span::{BytePos, MultiSpan, Span};
 use crate::imports::{Import, ImportKind, ImportResolver};
 use crate::path_names_to_string;
 use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind};
-use crate::{BindingError, CrateLint, HasGenericParams, LegacyScope, Module, ModuleOrUniformRoot};
+use crate::{
+    BindingError, CrateLint, HasGenericParams, MacroRulesScope, Module, ModuleOrUniformRoot,
+};
 use crate::{NameBinding, NameBindingKind, PrivacyError, VisResolutionError};
 use crate::{ParentScope, PathResult, ResolutionError, Resolver, Scope, ScopeSet, Segment};
 
@@ -498,12 +500,12 @@ impl<'a> Resolver<'a> {
                         }
                     }
                 }
-                Scope::MacroRules(legacy_scope) => {
+                Scope::MacroRules(macro_rules_scope) => {
-                    if let LegacyScope::Binding(legacy_binding) = legacy_scope {
+                    if let MacroRulesScope::Binding(macro_rules_binding) = macro_rules_scope {
-                        let res = legacy_binding.binding.res();
+                        let res = macro_rules_binding.binding.res();
                         if filter_fn(res) {
                             suggestions
-                                .push(TypoSuggestion::from_res(legacy_binding.ident.name, res))
+                                .push(TypoSuggestion::from_res(macro_rules_binding.ident.name, res))
                         }
                     }
                 }
@@ -756,7 +758,7 @@ impl<'a> Resolver<'a> {
             let msg = format!("unsafe traits like `{}` should be implemented explicitly", ident);
             err.span_note(ident.span, &msg);
         }
-        if self.macro_names.contains(&ident.modern()) {
+        if self.macro_names.contains(&ident.normalize_to_macros_2_0()) {
             err.help("have you added the `#[macro_use]` on the module/import?");
         }
     }

src/librustc_resolve/imports.rs

@@ -416,7 +416,8 @@ impl<'a> Resolver<'a> {
                 None => return Err((Undetermined, Weak::Yes)),
             };
             let tmp_parent_scope;
-            let (mut adjusted_parent_scope, mut ident) = (parent_scope, ident.modern());
+            let (mut adjusted_parent_scope, mut ident) =
+                (parent_scope, ident.normalize_to_macros_2_0());
             match ident.span.glob_adjust(module.expansion, glob_import.span) {
                 Some(Some(def)) => {
                     tmp_parent_scope =

src/librustc_resolve/late.rs

@@ -935,7 +935,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 _ => unreachable!(),
             };
 
-            let ident = param.ident.modern();
+            let ident = param.ident.normalize_to_macros_2_0();
             debug!("with_generic_param_rib: {}", param.id);
 
             if seen_bindings.contains_key(&ident) {
@@ -1464,7 +1464,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         // Add the binding to the local ribs, if it doesn't already exist in the bindings map.
         // (We must not add it if it's in the bindings map because that breaks the assumptions
         // later passes make about or-patterns.)
-        let ident = ident.modern_and_legacy();
+        let ident = ident.normalize_to_macro_rules();
 
         let mut bound_iter = bindings.iter().filter(|(_, set)| set.contains(&ident));
         // Already bound in a product pattern? e.g. `(a, a)` which is not allowed.
@@ -1873,7 +1873,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 self.diagnostic_metadata.unused_labels.insert(id, label.ident.span);
             }
             self.with_label_rib(NormalRibKind, |this| {
-                let ident = label.ident.modern_and_legacy();
+                let ident = label.ident.normalize_to_macro_rules();
                 this.label_ribs.last_mut().unwrap().bindings.insert(ident, id);
                 f(this);
             });
@@ -1949,7 +1949,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
             ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
                 let node_id = self.search_label(label.ident, |rib, ident| {
-                    rib.bindings.get(&ident.modern_and_legacy()).cloned()
+                    rib.bindings.get(&ident.normalize_to_macro_rules()).cloned()
                 });
                 match node_id {
                     None => {
@@ -2115,7 +2115,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             }
         }
 
-        ident.span = ident.span.modern();
+        ident.span = ident.span.normalize_to_macros_2_0();
         let mut search_module = self.parent_scope.module;
         loop {
             self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);

src/librustc_resolve/late/lifetimes.rs

@@ -62,7 +62,7 @@ impl RegionExt for Region {
         let def_id = hir_map.local_def_id(param.hir_id);
         let origin = LifetimeDefOrigin::from_param(param);
         debug!("Region::early: index={} def_id={:?}", i, def_id);
-        (param.name.modern(), Region::EarlyBound(i, def_id, origin))
+        (param.name.normalize_to_macros_2_0(), Region::EarlyBound(i, def_id, origin))
     }
 
     fn late(hir_map: &Map<'_>, param: &GenericParam<'_>) -> (ParamName, Region) {
@@ -73,7 +73,7 @@ impl RegionExt for Region {
             "Region::late: param={:?} depth={:?} def_id={:?} origin={:?}",
             param, depth, def_id, origin,
         );
-        (param.name.modern(), Region::LateBound(depth, def_id, origin))
+        (param.name.normalize_to_macros_2_0(), Region::LateBound(depth, def_id, origin))
     }
 
     fn late_anon(index: &Cell<u32>) -> Region {
@@ -1174,7 +1174,9 @@ fn extract_labels(ctxt: &mut LifetimeContext<'_, '_>, body: &hir::Body<'_>) {
 
                 Scope::Binder { ref lifetimes, s, .. } => {
                     // FIXME (#24278): non-hygienic comparison
-                    if let Some(def) = lifetimes.get(&hir::ParamName::Plain(label.modern())) {
+                    if let Some(def) =
+                        lifetimes.get(&hir::ParamName::Plain(label.normalize_to_macros_2_0()))
+                    {
                         let hir_id = tcx.hir().as_local_hir_id(def.id().unwrap()).unwrap();
 
                         signal_shadowing_problem(
@@ -1253,7 +1255,7 @@ fn object_lifetime_defaults_for_item(
     fn add_bounds(set: &mut Set1<hir::LifetimeName>, bounds: &[hir::GenericBound<'_>]) {
         for bound in bounds {
             if let hir::GenericBound::Outlives(ref lifetime) = *bound {
-                set.insert(lifetime.name.modern());
+                set.insert(lifetime.name.normalize_to_macros_2_0());
             }
         }
     }
@@ -1791,7 +1793,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                 Scope::Binder { ref lifetimes, s, .. } => {
                     match lifetime_ref.name {
                         LifetimeName::Param(param_name) => {
-                            if let Some(&def) = lifetimes.get(&param_name.modern()) {
+                            if let Some(&def) = lifetimes.get(&param_name.normalize_to_macros_2_0())
+                            {
                                 break Some(def.shifted(late_depth));
                             }
                         }
@@ -2542,7 +2545,9 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         let lifetimes: Vec<_> = params
             .iter()
             .filter_map(|param| match param.kind {
-                GenericParamKind::Lifetime { .. } => Some((param, param.name.modern())),
+                GenericParamKind::Lifetime { .. } => {
+                    Some((param, param.name.normalize_to_macros_2_0()))
+                }
                 _ => None,
             })
             .collect();
@@ -2659,7 +2664,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                 }
 
                 Scope::Binder { ref lifetimes, s, .. } => {
-                    if let Some(&def) = lifetimes.get(&param.name.modern()) {
+                    if let Some(&def) = lifetimes.get(&param.name.normalize_to_macros_2_0()) {
                         let hir_id = self.tcx.hir().as_local_hir_id(def.id().unwrap()).unwrap();
 
                         signal_shadowing_problem(
@@ -2797,7 +2802,7 @@ fn insert_late_bound_lifetimes(
                 // `'a: 'b` means both `'a` and `'b` are referenced
                 appears_in_where_clause
                     .regions
-                    .insert(hir::LifetimeName::Param(param.name.modern()));
+                    .insert(hir::LifetimeName::Param(param.name.normalize_to_macros_2_0()));
             }
         }
     }
@@ -2819,7 +2824,7 @@ fn insert_late_bound_lifetimes(
             hir::GenericParamKind::Type { .. } | hir::GenericParamKind::Const { .. } => continue,
         }
 
-        let lt_name = hir::LifetimeName::Param(param.name.modern());
+        let lt_name = hir::LifetimeName::Param(param.name.normalize_to_macros_2_0());
         // appears in the where clauses? early-bound.
         if appears_in_where_clause.regions.contains(&lt_name) {
             continue;
@@ -2883,7 +2888,7 @@ fn insert_late_bound_lifetimes(
         }
 
         fn visit_lifetime(&mut self, lifetime_ref: &'v hir::Lifetime) {
-            self.regions.insert(lifetime_ref.name.modern());
+            self.regions.insert(lifetime_ref.name.normalize_to_macros_2_0());
         }
     }
 
@@ -2900,7 +2905,7 @@ fn insert_late_bound_lifetimes(
         }
 
         fn visit_lifetime(&mut self, lifetime_ref: &'v hir::Lifetime) {
-            self.regions.insert(lifetime_ref.name.modern());
+            self.regions.insert(lifetime_ref.name.normalize_to_macros_2_0());
         }
     }
 }

src/librustc_resolve/lib.rs

@@ -58,7 +58,7 @@ use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_ne
 use diagnostics::{ImportSuggestion, Suggestion};
 use imports::{Import, ImportKind, ImportResolver, NameResolution};
 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
-use macros::{LegacyBinding, LegacyScope};
+use macros::{MacroRulesBinding, MacroRulesScope};
 
 type Res = def::Res<NodeId>;
 
@@ -94,7 +94,7 @@ impl Determinacy {
 enum Scope<'a> {
     DeriveHelpers(ExpnId),
     DeriveHelpersCompat,
-    MacroRules(LegacyScope<'a>),
+    MacroRules(MacroRulesScope<'a>),
     CrateRoot,
     Module(Module<'a>),
     RegisteredAttrs,
@@ -127,7 +127,7 @@ enum ScopeSet {
 pub struct ParentScope<'a> {
     module: Module<'a>,
     expansion: ExpnId,
-    legacy: LegacyScope<'a>,
+    macro_rules: MacroRulesScope<'a>,
     derives: &'a [ast::Path],
 }
 
@@ -135,7 +135,12 @@ 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>) -> ParentScope<'a> {
-        ParentScope { module, expansion: ExpnId::root(), legacy: LegacyScope::Empty, derives: &[] }
+        ParentScope {
+            module,
+            expansion: ExpnId::root(),
+            macro_rules: MacroRulesScope::Empty,
+            derives: &[],
+        }
     }
 }
 
@@ -419,7 +424,7 @@ impl ModuleKind {
 /// program) if all but one of them come from glob imports.
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 struct BindingKey {
-    /// The identifier for the binding, aways the `modern` version of the
+    /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
     /// identifier.
     ident: Ident,
     ns: Namespace,
@@ -613,7 +618,7 @@ enum AmbiguityKind {
     Import,
     BuiltinAttr,
     DeriveHelper,
-    LegacyVsModern,
+    MacroRulesVsModularized,
     GlobVsOuter,
     GlobVsGlob,
     GlobVsExpanded,
@@ -626,7 +631,9 @@ impl AmbiguityKind {
             AmbiguityKind::Import => "name vs any other name during import resolution",
             AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
             AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
-            AmbiguityKind::LegacyVsModern => "`macro_rules` vs non-`macro_rules` from other module",
+            AmbiguityKind::MacroRulesVsModularized => {
+                "`macro_rules` vs non-`macro_rules` from other module"
+            }
             AmbiguityKind::GlobVsOuter => {
                 "glob import vs any other name from outer scope during import/macro resolution"
             }
@@ -930,9 +937,9 @@ pub struct Resolver<'a> {
     /// Parent scopes in which the macros were invoked.
     /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
     invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
-    /// Legacy scopes *produced* by expanding the macro invocations,
+    /// `macro_rules` scopes *produced* by expanding the macro invocations,
     /// include all the `macro_rules` items and other invocations generated by them.
-    output_legacy_scopes: FxHashMap<ExpnId, LegacyScope<'a>>,
+    output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScope<'a>>,
     /// Helper attributes that are in scope for the given expansion.
     helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
 
@@ -965,7 +972,7 @@ pub struct ResolverArenas<'a> {
     name_bindings: arena::TypedArena<NameBinding<'a>>,
     imports: arena::TypedArena<Import<'a>>,
     name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
-    legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
+    macro_rules_bindings: arena::TypedArena<MacroRulesBinding<'a>>,
     ast_paths: arena::TypedArena<ast::Path>,
 }
 
@@ -989,8 +996,11 @@ impl<'a> ResolverArenas<'a> {
     fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
         self.name_resolutions.alloc(Default::default())
     }
-    fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
+    fn alloc_macro_rules_binding(
-        self.legacy_bindings.alloc(binding)
+        &'a self,
+        binding: MacroRulesBinding<'a>,
+    ) -> &'a MacroRulesBinding<'a> {
+        self.macro_rules_bindings.alloc(binding)
     }
     fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
         self.ast_paths.alloc_from_iter(paths.iter().cloned())
@@ -1210,7 +1220,7 @@ impl<'a> Resolver<'a> {
             dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
             non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
             invocation_parent_scopes,
-            output_legacy_scopes: Default::default(),
+            output_macro_rules_scopes: Default::default(),
             helper_attrs: Default::default(),
             macro_defs,
             local_macro_def_scopes: FxHashMap::default(),
@@ -1352,7 +1362,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
-        let ident = ident.modern();
+        let ident = ident.normalize_to_macros_2_0();
         let disambiguator = if ident.name == kw::Underscore {
             self.underscore_disambiguator += 1;
             self.underscore_disambiguator
@@ -1403,7 +1413,7 @@ impl<'a> Resolver<'a> {
             // Avoid marking `extern crate` items that refer to a name from extern prelude,
             // but not introduce it, as used if they are accessed from lexical scope.
             if is_lexical_scope {
-                if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
+                if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
                     if let Some(crate_item) = entry.extern_crate_item {
                         if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
                             return;
@@ -1465,7 +1475,7 @@ impl<'a> Resolver<'a> {
         //    derives (you need to resolve the derive first to add helpers into scope), but they
         //    should be available before the derive is expanded for compatibility.
         //    It's mess in general, so we are being conservative for now.
-        // 1-3. `macro_rules` (open, not controlled), loop through legacy scopes. Have higher
+        // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
         //    priority than prelude macros, but create ambiguities with macros in modules.
         // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
         //    (open, not controlled). Have higher priority than prelude macros, but create
@@ -1490,7 +1500,7 @@ impl<'a> Resolver<'a> {
             TypeNS | ValueNS => Scope::Module(module),
             MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
         };
-        let mut ident = ident.modern();
+        let mut ident = ident.normalize_to_macros_2_0();
         let mut use_prelude = !module.no_implicit_prelude;
 
         loop {
@@ -1530,16 +1540,18 @@ impl<'a> Resolver<'a> {
                     }
                 }
                 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
-                Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.legacy),
+                Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
-                Scope::MacroRules(legacy_scope) => match legacy_scope {
+                Scope::MacroRules(macro_rules_scope) => match macro_rules_scope {
-                    LegacyScope::Binding(binding) => Scope::MacroRules(binding.parent_legacy_scope),
+                    MacroRulesScope::Binding(binding) => {
-                    LegacyScope::Invocation(invoc_id) => Scope::MacroRules(
+                        Scope::MacroRules(binding.parent_macro_rules_scope)
-                        self.output_legacy_scopes
+                    }
+                    MacroRulesScope::Invocation(invoc_id) => Scope::MacroRules(
+                        self.output_macro_rules_scopes
                             .get(&invoc_id)
                             .cloned()
-                            .unwrap_or(self.invocation_parent_scopes[&invoc_id].legacy),
+                            .unwrap_or(self.invocation_parent_scopes[&invoc_id].macro_rules),
                     ),
-                    LegacyScope::Empty => Scope::Module(module),
+                    MacroRulesScope::Empty => Scope::Module(module),
                 },
                 Scope::CrateRoot => match ns {
                     TypeNS => {
@@ -1610,18 +1622,18 @@ impl<'a> Resolver<'a> {
         if ident.name == kw::Invalid {
             return Some(LexicalScopeBinding::Res(Res::Err));
         }
-        let (general_span, modern_span) = if ident.name == kw::SelfUpper {
+        let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
             // FIXME(jseyfried) improve `Self` hygiene
             let empty_span = ident.span.with_ctxt(SyntaxContext::root());
             (empty_span, empty_span)
         } else if ns == TypeNS {
-            let modern_span = ident.span.modern();
+            let normalized_span = ident.span.normalize_to_macros_2_0();
-            (modern_span, modern_span)
+            (normalized_span, normalized_span)
         } else {
-            (ident.span.modern_and_legacy(), ident.span.modern())
+            (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
         };
         ident.span = general_span;
-        let modern_ident = Ident { span: modern_span, ..ident };
+        let normalized_ident = Ident { span: normalized_span, ..ident };
 
         // Walk backwards up the ribs in scope.
         let record_used = record_used_id.is_some();
@@ -1629,8 +1641,8 @@ impl<'a> Resolver<'a> {
         for i in (0..ribs.len()).rev() {
             debug!("walk rib\n{:?}", ribs[i].bindings);
             // Use the rib kind to determine whether we are resolving parameters
-            // (modern hygiene) or local variables (legacy hygiene).
+            // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
-            let rib_ident = if ribs[i].kind.contains_params() { modern_ident } else { ident };
+            let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
             if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
                 // The ident resolves to a type parameter or local variable.
                 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
@@ -1673,7 +1685,7 @@ impl<'a> Resolver<'a> {
             }
         }
 
-        ident = modern_ident;
+        ident = normalized_ident;
         let mut poisoned = None;
         loop {
             let opt_module = if let Some(node_id) = record_used_id {
@@ -1842,14 +1854,14 @@ impl<'a> Resolver<'a> {
         let mut adjusted_parent_scope = parent_scope;
         match module {
             ModuleOrUniformRoot::Module(m) => {
-                if let Some(def) = ident.span.modernize_and_adjust(m.expansion) {
+                if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
                     tmp_parent_scope =
                         ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
                     adjusted_parent_scope = &tmp_parent_scope;
                 }
             }
             ModuleOrUniformRoot::ExternPrelude => {
-                ident.span.modernize_and_adjust(ExpnId::root());
+                ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
             }
             ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
                 // No adjustments
@@ -1872,14 +1884,14 @@ impl<'a> Resolver<'a> {
         let mark = if ident.name == kw::DollarCrate {
             // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
             // we don't want to pretend that the `macro_rules!` definition is in the `macro`
-            // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
+            // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
             // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
             // definitions actually produced by `macro` and `macro` definitions produced by
             // `macro_rules!`, but at least such configurations are not stable yet.
-            ctxt = ctxt.modern_and_legacy();
+            ctxt = ctxt.normalize_to_macro_rules();
             let mut iter = ctxt.marks().into_iter().rev().peekable();
             let mut result = None;
-            // Find the last modern mark from the end if it exists.
+            // Find the last opaque mark from the end if it exists.
             while let Some(&(mark, transparency)) = iter.peek() {
                 if transparency == Transparency::Opaque {
                     result = Some(mark);
@@ -1888,7 +1900,7 @@ impl<'a> Resolver<'a> {
                     break;
                 }
             }
-            // Then find the last legacy mark from the end if it exists.
+            // Then find the last semi-transparent mark from the end if it exists.
             for (mark, transparency) in iter {
                 if transparency == Transparency::SemiTransparent {
                     result = Some(mark);
@@ -1898,7 +1910,7 @@ impl<'a> Resolver<'a> {
             }
             result
         } else {
-            ctxt = ctxt.modern();
+            ctxt = ctxt.normalize_to_macros_2_0();
             ctxt.adjust(ExpnId::root())
         };
         let module = match mark {
@@ -1910,7 +1922,7 @@ impl<'a> Resolver<'a> {
 
     fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
         let mut module = self.get_module(module.normal_ancestor_id);
-        while module.span.ctxt().modern() != *ctxt {
+        while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
             let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
             module = self.get_module(parent.normal_ancestor_id);
         }
@@ -1978,7 +1990,7 @@ impl<'a> Resolver<'a> {
 
             if ns == TypeNS {
                 if allow_super && name == kw::Super {
-                    let mut ctxt = ident.span.ctxt().modern();
+                    let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
                     let self_module = match i {
                         0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
                         _ => match module {
@@ -2004,7 +2016,7 @@ impl<'a> Resolver<'a> {
                 }
                 if i == 0 {
                     if name == kw::SelfLower {
-                        let mut ctxt = ident.span.ctxt().modern();
+                        let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
                         module = Some(ModuleOrUniformRoot::Module(
                             self.resolve_self(&mut ctxt, parent_scope.module),
                         ));
@@ -2413,21 +2425,21 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    fn disambiguate_legacy_vs_modern(
+    fn disambiguate_macro_rules_vs_modularized(
         &self,
-        legacy: &'a NameBinding<'a>,
+        macro_rules: &'a NameBinding<'a>,
-        modern: &'a NameBinding<'a>,
+        modularized: &'a NameBinding<'a>,
     ) -> bool {
-        // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
+        // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
         // is disambiguated to mitigate regressions from macro modularization.
         // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
         match (
-            self.binding_parent_modules.get(&PtrKey(legacy)),
+            self.binding_parent_modules.get(&PtrKey(macro_rules)),
-            self.binding_parent_modules.get(&PtrKey(modern)),
+            self.binding_parent_modules.get(&PtrKey(modularized)),
         ) {
-            (Some(legacy), Some(modern)) => {
+            (Some(macro_rules), Some(modularized)) => {
-                legacy.normal_ancestor_id == modern.normal_ancestor_id
+                macro_rules.normal_ancestor_id == modularized.normal_ancestor_id
-                    && modern.is_ancestor_of(legacy)
+                    && modularized.is_ancestor_of(macro_rules)
             }
             _ => false,
         }
@@ -2757,7 +2769,7 @@ impl<'a> Resolver<'a> {
             // Make sure `self`, `super` etc produce an error when passed to here.
             return None;
         }
-        self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
+        self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
             if let Some(binding) = entry.extern_crate_item {
                 if !speculative && entry.introduced_by_item {
                     self.record_use(ident, TypeNS, binding, false);

src/librustc_resolve/macros.rs

@@ -33,26 +33,26 @@ use std::{mem, ptr};
 type Res = def::Res<NodeId>;
 
 /// Binding produced by a `macro_rules` item.
-/// Not modularized, can shadow previous legacy bindings, etc.
+/// Not modularized, can shadow previous `macro_rules` bindings, etc.
 #[derive(Debug)]
-pub struct LegacyBinding<'a> {
+pub struct MacroRulesBinding<'a> {
     crate binding: &'a NameBinding<'a>,
-    /// Legacy scope into which the `macro_rules` item was planted.
+    /// `macro_rules` scope into which the `macro_rules` item was planted.
-    crate parent_legacy_scope: LegacyScope<'a>,
+    crate parent_macro_rules_scope: MacroRulesScope<'a>,
     crate ident: Ident,
 }
 
 /// The scope introduced by a `macro_rules!` macro.
 /// This starts at the macro's definition and ends at the end of the macro's parent
 /// module (named or unnamed), or even further if it escapes with `#[macro_use]`.
-/// Some macro invocations need to introduce legacy scopes too because they
+/// Some macro invocations need to introduce `macro_rules` scopes too because they
 /// can potentially expand into macro definitions.
 #[derive(Copy, Clone, Debug)]
-pub enum LegacyScope<'a> {
+pub enum MacroRulesScope<'a> {
     /// Empty "root" scope at the crate start containing no names.
     Empty,
     /// The scope introduced by a `macro_rules!` macro definition.
-    Binding(&'a LegacyBinding<'a>),
+    Binding(&'a MacroRulesBinding<'a>),
     /// The scope introduced by a macro invocation that can potentially
     /// create a `macro_rules!` macro definition.
     Invocation(ExpnId),
@@ -159,8 +159,8 @@ impl<'a> base::Resolver for Resolver<'a> {
         // Integrate the new AST fragment into all the definition and module structures.
         // We are inside the `expansion` now, but other parent scope components are still the same.
         let parent_scope = ParentScope { expansion, ..self.invocation_parent_scopes[&expansion] };
-        let output_legacy_scope = self.build_reduced_graph(fragment, parent_scope);
+        let output_macro_rules_scope = self.build_reduced_graph(fragment, parent_scope);
-        self.output_legacy_scopes.insert(expansion, output_legacy_scope);
+        self.output_macro_rules_scopes.insert(expansion, output_macro_rules_scope);
 
         parent_scope.module.unexpanded_invocations.borrow_mut().remove(&expansion);
     }
@@ -258,7 +258,13 @@ impl<'a> base::Resolver for Resolver<'a> {
                             force,
                         ) {
                             Ok((Some(ext), _)) => {
-                                let span = path.segments.last().unwrap().ident.span.modern();
+                                let span = path
+                                    .segments
+                                    .last()
+                                    .unwrap()
+                                    .ident
+                                    .span
+                                    .normalize_to_macros_2_0();
                                 helper_attrs.extend(
                                     ext.helper_attrs.iter().map(|name| Ident::new(*name, span)),
                                 );
@@ -608,12 +614,14 @@ impl<'a> Resolver<'a> {
                         }
                         result
                     }
-                    Scope::MacroRules(legacy_scope) => match legacy_scope {
+                    Scope::MacroRules(macro_rules_scope) => match macro_rules_scope {
-                        LegacyScope::Binding(legacy_binding) if ident == legacy_binding.ident => {
+                        MacroRulesScope::Binding(macro_rules_binding)
-                            Ok((legacy_binding.binding, Flags::MACRO_RULES))
+                            if ident == macro_rules_binding.ident =>
+                        {
+                            Ok((macro_rules_binding.binding, Flags::MACRO_RULES))
                         }
-                        LegacyScope::Invocation(invoc_id)
+                        MacroRulesScope::Invocation(invoc_id)
-                            if !this.output_legacy_scopes.contains_key(&invoc_id) =>
+                            if !this.output_macro_rules_scopes.contains_key(&invoc_id) =>
                         {
                             Err(Determinacy::Undetermined)
                         }
@@ -759,16 +767,18 @@ impl<'a> Resolver<'a> {
                                     Some(AmbiguityKind::DeriveHelper)
                                 } else if innermost_flags.contains(Flags::MACRO_RULES)
                                     && flags.contains(Flags::MODULE)
-                                    && !this
+                                    && !this.disambiguate_macro_rules_vs_modularized(
-                                        .disambiguate_legacy_vs_modern(innermost_binding, binding)
+                                        innermost_binding,
+                                        binding,
+                                    )
                                     || flags.contains(Flags::MACRO_RULES)
                                         && innermost_flags.contains(Flags::MODULE)
-                                        && !this.disambiguate_legacy_vs_modern(
+                                        && !this.disambiguate_macro_rules_vs_modularized(
                                             binding,
                                             innermost_binding,
                                         )
                                 {
-                                    Some(AmbiguityKind::LegacyVsModern)
+                                    Some(AmbiguityKind::MacroRulesVsModularized)
                                 } else if innermost_binding.is_glob_import() {
                                     Some(AmbiguityKind::GlobVsOuter)
                                 } else if innermost_binding

src/librustc_span/hygiene.rs

@@ -201,11 +201,11 @@ impl HygieneData {
         true
     }
 
-    fn modern(&self, ctxt: SyntaxContext) -> SyntaxContext {
+    fn normalize_to_macros_2_0(&self, ctxt: SyntaxContext) -> SyntaxContext {
         self.syntax_context_data[ctxt.0 as usize].opaque
     }
 
-    fn modern_and_legacy(&self, ctxt: SyntaxContext) -> SyntaxContext {
+    fn normalize_to_macro_rules(&self, ctxt: SyntaxContext) -> SyntaxContext {
         self.syntax_context_data[ctxt.0 as usize].opaque_and_semitransparent
     }
 
@@ -266,9 +266,9 @@ impl HygieneData {
 
         let call_site_ctxt = self.expn_data(expn_id).call_site.ctxt();
         let mut call_site_ctxt = if transparency == Transparency::SemiTransparent {
-            self.modern(call_site_ctxt)
+            self.normalize_to_macros_2_0(call_site_ctxt)
         } else {
-            self.modern_and_legacy(call_site_ctxt)
+            self.normalize_to_macro_rules(call_site_ctxt)
         };
 
         if call_site_ctxt == SyntaxContext::root() {
@@ -491,10 +491,10 @@ impl SyntaxContext {
         HygieneData::with(|data| data.adjust(self, expn_id))
     }
 
-    /// Like `SyntaxContext::adjust`, but also modernizes `self`.
+    /// Like `SyntaxContext::adjust`, but also normalizes `self` to macros 2.0.
-    pub fn modernize_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
+    pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
         HygieneData::with(|data| {
-            *self = data.modern(*self);
+            *self = data.normalize_to_macros_2_0(*self);
             data.adjust(self, expn_id)
         })
     }
@@ -527,7 +527,7 @@ impl SyntaxContext {
     pub fn glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option<Option<ExpnId>> {
         HygieneData::with(|data| {
             let mut scope = None;
-            let mut glob_ctxt = data.modern(glob_span.ctxt());
+            let mut glob_ctxt = data.normalize_to_macros_2_0(glob_span.ctxt());
             while !data.is_descendant_of(expn_id, data.outer_expn(glob_ctxt)) {
                 scope = Some(data.remove_mark(&mut glob_ctxt).0);
                 if data.remove_mark(self).0 != scope.unwrap() {
@@ -558,7 +558,7 @@ impl SyntaxContext {
                 return None;
             }
 
-            let mut glob_ctxt = data.modern(glob_span.ctxt());
+            let mut glob_ctxt = data.normalize_to_macros_2_0(glob_span.ctxt());
             let mut marks = Vec::new();
             while !data.is_descendant_of(expn_id, data.outer_expn(glob_ctxt)) {
                 marks.push(data.remove_mark(&mut glob_ctxt));
@@ -574,20 +574,20 @@ impl SyntaxContext {
 
     pub fn hygienic_eq(self, other: SyntaxContext, expn_id: ExpnId) -> bool {
         HygieneData::with(|data| {
-            let mut self_modern = data.modern(self);
+            let mut self_normalized = data.normalize_to_macros_2_0(self);
-            data.adjust(&mut self_modern, expn_id);
+            data.adjust(&mut self_normalized, expn_id);
-            self_modern == data.modern(other)
+            self_normalized == data.normalize_to_macros_2_0(other)
         })
     }
 
     #[inline]
-    pub fn modern(self) -> SyntaxContext {
+    pub fn normalize_to_macros_2_0(self) -> SyntaxContext {
-        HygieneData::with(|data| data.modern(self))
+        HygieneData::with(|data| data.normalize_to_macros_2_0(self))
     }
 
     #[inline]
-    pub fn modern_and_legacy(self) -> SyntaxContext {
+    pub fn normalize_to_macro_rules(self) -> SyntaxContext {
-        HygieneData::with(|data| data.modern_and_legacy(self))
+        HygieneData::with(|data| data.normalize_to_macro_rules(self))
     }
 
     #[inline]

src/librustc_span/lib.rs

@@ -548,9 +548,9 @@ impl Span {
     }
 
     #[inline]
-    pub fn modernize_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
+    pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
         let mut span = self.data();
-        let mark = span.ctxt.modernize_and_adjust(expn_id);
+        let mark = span.ctxt.normalize_to_macros_2_0_and_adjust(expn_id);
         *self = Span::new(span.lo, span.hi, span.ctxt);
         mark
     }
@@ -576,15 +576,15 @@ impl Span {
     }
 
     #[inline]
-    pub fn modern(self) -> Span {
+    pub fn normalize_to_macros_2_0(self) -> Span {
         let span = self.data();
-        span.with_ctxt(span.ctxt.modern())
+        span.with_ctxt(span.ctxt.normalize_to_macros_2_0())
     }
 
     #[inline]
-    pub fn modern_and_legacy(self) -> Span {
+    pub fn normalize_to_macro_rules(self) -> Span {
         let span = self.data();
-        span.with_ctxt(span.ctxt.modern_and_legacy())
+        span.with_ctxt(span.ctxt.normalize_to_macro_rules())
     }
 }
 

src/librustc_span/symbol.rs

@@ -853,12 +853,12 @@ impl Ident {
     }
 
     /// "Normalize" ident for use in comparisons using "item hygiene".
-    /// Identifiers with same string value become same if they came from the same "modern" macro
+    /// Identifiers with same string value become same if they came from the same macro 2.0 macro
     /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
-    /// different "modern" macros.
+    /// different macro 2.0 macros.
     /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
-    pub fn modern(self) -> Ident {
+    pub fn normalize_to_macros_2_0(self) -> Ident {
-        Ident::new(self.name, self.span.modern())
+        Ident::new(self.name, self.span.normalize_to_macros_2_0())
     }
 
     /// "Normalize" ident for use in comparisons using "local variable hygiene".
@@ -866,8 +866,8 @@ impl Ident {
     /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
     /// non-transparent macros.
     /// Technically, this operation strips all transparent marks from ident's syntactic context.
-    pub fn modern_and_legacy(self) -> Ident {
+    pub fn normalize_to_macro_rules(self) -> Ident {
-        Ident::new(self.name, self.span.modern_and_legacy())
+        Ident::new(self.name, self.span.normalize_to_macro_rules())
     }
 
     /// Convert the name to a `SymbolStr`. This is a slowish operation because

src/librustc_typeck/astconv.rs

@@ -1441,12 +1441,14 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let (assoc_ident, def_scope) =
             tcx.adjust_ident_and_get_scope(binding.item_name, candidate.def_id(), hir_ref_id);
 
-        // We have already adjusted the item name above, so compare with `ident.modern()` instead
+        // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead
         // of calling `filter_by_name_and_kind`.
         let assoc_ty = tcx
             .associated_items(candidate.def_id())
             .filter_by_name_unhygienic(assoc_ident.name)
-            .find(|i| i.kind == ty::AssocKind::Type && i.ident.modern() == assoc_ident)
+            .find(|i| {
+                i.kind == ty::AssocKind::Type && i.ident.normalize_to_macros_2_0() == assoc_ident
+            })
             .expect("missing associated type");
 
         if !assoc_ty.vis.is_accessible_from(def_scope, tcx) {
@@ -2298,12 +2300,15 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let (assoc_ident, def_scope) =
             tcx.adjust_ident_and_get_scope(assoc_ident, trait_did, hir_ref_id);
 
-        // We have already adjusted the item name above, so compare with `ident.modern()` instead
+        // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead
         // of calling `filter_by_name_and_kind`.
         let item = tcx
             .associated_items(trait_did)
             .in_definition_order()
-            .find(|i| i.kind.namespace() == Namespace::TypeNS && i.ident.modern() == assoc_ident)
+            .find(|i| {
+                i.kind.namespace() == Namespace::TypeNS
+                    && i.ident.normalize_to_macros_2_0() == assoc_ident
+            })
             .expect("missing associated type");
 
         let ty = self.projected_ty_from_poly_trait_ref(span, item.def_id, assoc_segment, bound);

src/librustc_typeck/check/expr.rs

@@ -1203,7 +1203,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .fields
             .iter()
             .enumerate()
-            .map(|(i, field)| (field.ident.modern(), (i, field)))
+            .map(|(i, field)| (field.ident.normalize_to_macros_2_0(), (i, field)))
             .collect::<FxHashMap<_, _>>();
 
         let mut seen_fields = FxHashMap::default();
@@ -1469,7 +1469,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     let (ident, def_scope) =
                         self.tcx.adjust_ident_and_get_scope(field, base_def.did, self.body_id);
                     let fields = &base_def.non_enum_variant().fields;
-                    if let Some(index) = fields.iter().position(|f| f.ident.modern() == ident) {
+                    if let Some(index) =
+                        fields.iter().position(|f| f.ident.normalize_to_macros_2_0() == ident)
+                    {
                         let field = &fields[index];
                         let field_ty = self.field_ty(expr.span, field, substs);
                         // Save the index of all fields regardless of their visibility in case

src/librustc_typeck/check/pat.rs

@@ -1023,7 +1023,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .fields
             .iter()
             .enumerate()
-            .map(|(i, field)| (field.ident.modern(), (i, field)))
+            .map(|(i, field)| (field.ident.normalize_to_macros_2_0(), (i, field)))
             .collect::<FxHashMap<_, _>>();
 
         // Keep track of which fields have already appeared in the pattern.
@@ -1064,7 +1064,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let mut unmentioned_fields = variant
             .fields
             .iter()
-            .map(|field| field.ident.modern())
+            .map(|field| field.ident.normalize_to_macros_2_0())
             .filter(|ident| !used_fields.contains_key(&ident))
             .collect::<Vec<_>>();
 

src/librustc_typeck/coherence/inherent_impls_overlap.rs

@@ -26,7 +26,8 @@ impl InherentOverlapChecker<'tcx> {
             let collision = impl_items2.filter_by_name_unhygienic(item1.ident.name).any(|item2| {
                 // Symbols and namespace match, compare hygienically.
                 item1.kind.namespace() == item2.kind.namespace()
-                    && item1.ident.modern() == item2.ident.modern()
+                    && item1.ident.normalize_to_macros_2_0()
+                        == item2.ident.normalize_to_macros_2_0()
             });
 
             if collision {
@@ -50,11 +51,12 @@ impl InherentOverlapChecker<'tcx> {
             let collision = impl_items2.filter_by_name_unhygienic(item1.ident.name).find(|item2| {
                 // Symbols and namespace match, compare hygienically.
                 item1.kind.namespace() == item2.kind.namespace()
-                    && item1.ident.modern() == item2.ident.modern()
+                    && item1.ident.normalize_to_macros_2_0()
+                        == item2.ident.normalize_to_macros_2_0()
             });
 
             if let Some(item2) = collision {
-                let name = item1.ident.modern();
+                let name = item1.ident.normalize_to_macros_2_0();
                 let mut err = struct_span_err!(
                     self.tcx.sess,
                     self.tcx.span_of_impl(item1.def_id).unwrap(),

src/librustc_typeck/collect.rs

@@ -828,7 +828,7 @@ fn convert_variant(
         .iter()
         .map(|f| {
             let fid = tcx.hir().local_def_id(f.hir_id);
-            let dup_span = seen_fields.get(&f.ident.modern()).cloned();
+            let dup_span = seen_fields.get(&f.ident.normalize_to_macros_2_0()).cloned();
             if let Some(prev_span) = dup_span {
                 struct_span_err!(
                     tcx.sess,
@@ -841,7 +841,7 @@ fn convert_variant(
                 .span_label(prev_span, format!("`{}` first declared here", f.ident))
                 .emit();
             } else {
-                seen_fields.insert(f.ident.modern(), f.span);
+                seen_fields.insert(f.ident.normalize_to_macros_2_0(), f.span);
             }
 
             ty::FieldDef {

src/librustc_typeck/impl_wf_check.rs

@@ -227,7 +227,7 @@ fn enforce_impl_items_are_distinct(tcx: TyCtxt<'_>, impl_item_refs: &[hir::ImplI
             hir::ImplItemKind::TyAlias(_) => &mut seen_type_items,
             _ => &mut seen_value_items,
         };
-        match seen_items.entry(impl_item.ident.modern()) {
+        match seen_items.entry(impl_item.ident.normalize_to_macros_2_0()) {
             Occupied(entry) => {
                 let mut err = struct_span_err!(
                     tcx.sess,