Rollup merge of rust-lang#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

Author: Dylan-DPC

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)) {
-            Some(actual_expansion) => {
-                self.hir().definitions().parent_module_of_macro_def(actual_expansion)
-            }
-            None => self.parent_module(block),
-        };
+        let scope =
+            match ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope))
+            {
+                Some(actual_expansion) => {
+                    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 !legacy || attr::contains_name(&i.attrs, sym::macro_export) {
+        if let ItemKind::MacroDef(MacroDef { ref body, macro_rules }) = i.kind {
+            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 {
-        ast::ItemKind::MacroDef(macro_def) => (macro_def.legacy, macro_def.body.inner_tokens()),
+    let (macro_rules, body) = match &def.kind {
+        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;
         }