Remove scope placeholders, remove method add_macro of ext::base::Resolver.

Author: jseyfried

src/librustc_resolve/build_reduced_graph.rs

@@ -697,9 +697,13 @@ impl<'a, 'b> Visitor<'a> for BuildReducedGraphVisitor<'a, 'b> {
 
     fn visit_item(&mut self, item: &'a Item) {
         let macro_use = match item.node {
-            ItemKind::Mac(..) if item.id == ast::DUMMY_NODE_ID => return, // Scope placeholder
-            ItemKind::Mac(..) => {
-                return self.legacy_scope = LegacyScope::Expansion(self.visit_invoc(item.id));
+            ItemKind::Mac(ref mac) => {
+                if mac.node.path.segments.is_empty() {
+                    self.legacy_scope = LegacyScope::Expansion(self.visit_invoc(item.id));
+                } else {
+                    self.resolver.define_macro(item, &mut self.legacy_scope);
+                }
+                return
             }
             ItemKind::Mod(..) => self.resolver.contains_macro_use(&item.attrs),
             _ => false,

src/librustc_resolve/macros.rs

@@ -23,8 +23,8 @@ use syntax::ast::{self, Name, Ident};
 use syntax::attr;
 use syntax::errors::DiagnosticBuilder;
 use syntax::ext::base::{self, Determinacy, MultiModifier, MultiDecorator};
-use syntax::ext::base::{NormalTT, SyntaxExtension};
-use syntax::ext::expand::Expansion;
+use syntax::ext::base::{NormalTT, Resolver as SyntaxResolver, SyntaxExtension};
+use syntax::ext::expand::{Expansion, mark_tts};
 use syntax::ext::hygiene::Mark;
 use syntax::ext::tt::macro_rules;
 use syntax::feature_gate::{emit_feature_err, GateIssue};
@@ -139,34 +139,6 @@ impl<'a> base::Resolver for Resolver<'a> {
         invocation.expansion.set(visitor.legacy_scope);
     }
 
-    fn add_macro(&mut self, scope: Mark, mut def: ast::MacroDef) {
-        if def.ident.name == "macro_rules" {
-            self.session.span_err(def.span, "user-defined macros may not be named `macro_rules`");
-        }
-
-        let invocation = self.invocations[&scope];
-        let binding = self.arenas.alloc_legacy_binding(LegacyBinding {
-            parent: Cell::new(invocation.legacy_scope.get()),
-            name: def.ident.name,
-            ext: Rc::new(macro_rules::compile(&self.session.parse_sess, &def)),
-            span: def.span,
-        });
-        invocation.legacy_scope.set(LegacyScope::Binding(binding));
-        self.macro_names.insert(def.ident.name);
-
-        if attr::contains_name(&def.attrs, "macro_export") {
-            def.id = self.next_node_id();
-            DefCollector::new(&mut self.definitions).with_parent(CRATE_DEF_INDEX, |collector| {
-                collector.visit_macro_def(&def)
-            });
-            self.macro_exports.push(Export {
-                name: def.ident.name,
-                def: Def::Macro(self.definitions.local_def_id(def.id)),
-            });
-            self.exported_macros.push(def);
-        }
-    }
-
     fn add_ext(&mut self, ident: ast::Ident, ext: Rc<SyntaxExtension>) {
         if let NormalTT(..) = *ext {
             self.macro_names.insert(ident.name);
@@ -444,4 +416,47 @@ impl<'a> Resolver<'a> {
             expansion.visit_with(def_collector)
         });
     }
+
+    pub fn define_macro(&mut self, item: &ast::Item, legacy_scope: &mut LegacyScope<'a>) {
+        let tts = match item.node {
+            ast::ItemKind::Mac(ref mac) => &mac.node.tts,
+            _ => unreachable!(),
+        };
+
+        if item.ident.name == "macro_rules" {
+            self.session.span_err(item.span, "user-defined macros may not be named `macro_rules`");
+        }
+
+        let mark = Mark::from_placeholder_id(item.id);
+        let invocation = self.invocations[&mark];
+        invocation.module.set(self.current_module);
+
+        let mut def = ast::MacroDef {
+            ident: item.ident,
+            attrs: item.attrs.clone(),
+            id: ast::DUMMY_NODE_ID,
+            span: item.span,
+            body: mark_tts(tts, mark),
+        };
+
+        *legacy_scope = LegacyScope::Binding(self.arenas.alloc_legacy_binding(LegacyBinding {
+            parent: Cell::new(*legacy_scope),
+            name: def.ident.name,
+            ext: Rc::new(macro_rules::compile(&self.session.parse_sess, &def)),
+            span: def.span,
+        }));
+        self.macro_names.insert(def.ident.name);
+
+        if attr::contains_name(&def.attrs, "macro_export") {
+            def.id = self.next_node_id();
+            DefCollector::new(&mut self.definitions).with_parent(CRATE_DEF_INDEX, |collector| {
+                collector.visit_macro_def(&def)
+            });
+            self.macro_exports.push(Export {
+                name: def.ident.name,
+                def: Def::Macro(self.definitions.local_def_id(def.id)),
+            });
+            self.exported_macros.push(def);
+        }
+    }
 }

src/libsyntax/ext/base.rs

@@ -520,7 +520,6 @@ pub trait Resolver {
     fn eliminate_crate_var(&mut self, item: P<ast::Item>) -> P<ast::Item>;
 
     fn visit_expansion(&mut self, mark: Mark, expansion: &Expansion);
-    fn add_macro(&mut self, scope: Mark, def: ast::MacroDef);
     fn add_ext(&mut self, ident: ast::Ident, ext: Rc<SyntaxExtension>);
     fn add_expansions_at_stmt(&mut self, id: ast::NodeId, macros: Vec<Mark>);
 
@@ -544,7 +543,6 @@ impl Resolver for DummyResolver {
     fn eliminate_crate_var(&mut self, item: P<ast::Item>) -> P<ast::Item> { item }
 
     fn visit_expansion(&mut self, _invoc: Mark, _expansion: &Expansion) {}
-    fn add_macro(&mut self, _scope: Mark, _def: ast::MacroDef) {}
     fn add_ext(&mut self, _ident: ast::Ident, _ext: Rc<SyntaxExtension>) {}
     fn add_expansions_at_stmt(&mut self, _id: ast::NodeId, _macros: Vec<Mark>) {}
 

src/libsyntax/ext/expand.rs

@@ -392,14 +392,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         };
         let Mac_ { path, tts, .. } = mac.node;
 
-        // Detect use of feature-gated or invalid attributes on macro invoations
-        // since they will not be detected after macro expansion.
-        for attr in attrs.iter() {
-            feature_gate::check_attribute(&attr, &self.cx.parse_sess,
-                                          &self.cx.parse_sess.codemap(),
-                                          &self.cx.ecfg.features.unwrap());
-        }
-
         let extname = path.segments.last().unwrap().identifier.name;
         let ident = ident.unwrap_or(keywords::Invalid.ident());
         let marked_tts = mark_tts(&tts, mark);
@@ -601,6 +593,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
     fn collect_bang(
         &mut self, mac: ast::Mac, attrs: Vec<ast::Attribute>, span: Span, kind: ExpansionKind,
     ) -> Expansion {
+        self.check_attributes(&attrs);
         self.collect(kind, InvocationKind::Bang { attrs: attrs, mac: mac, ident: None, span: span })
     }
 
@@ -622,6 +615,16 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
     fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
         self.cfg.configure(node)
     }
+
+    // Detect use of feature-gated or invalid attributes on macro invocations
+    // since they will not be detected after macro expansion.
+    fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
+        let codemap = &self.cx.parse_sess.codemap();
+        let features = self.cx.ecfg.features.unwrap();
+        for attr in attrs.iter() {
+            feature_gate::check_attribute(&attr, &self.cx.parse_sess, codemap, features);
+        }
+    }
 }
 
 // These are pretty nasty. Ideally, we would keep the tokens around, linked from
@@ -740,14 +743,18 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
 
         match item.node {
             ast::ItemKind::Mac(..) => {
-                if match item.node {
-                    ItemKind::Mac(ref mac) => mac.node.path.segments.is_empty(),
-                    _ => unreachable!(),
-                } {
-                    return SmallVector::one(item);
-                }
+                self.check_attributes(&item.attrs);
+                let is_macro_def = if let ItemKind::Mac(ref mac) = item.node {
+                    mac.node.path.segments[0].identifier.name == "macro_rules"
+                } else {
+                    unreachable!()
+                };
 
-                item.and_then(|item| match item.node {
+                item.and_then(|mut item| match item.node {
+                    ItemKind::Mac(_) if is_macro_def => {
+                        item.id = ast::NodeId::from_u32(Mark::fresh().as_u32());
+                        SmallVector::one(P(item))
+                    }
                     ItemKind::Mac(mac) => {
                         self.collect(ExpansionKind::Items, InvocationKind::Bang {
                             mac: mac,

src/libsyntax/ext/placeholders.rs

@@ -12,9 +12,10 @@ use ast;
 use codemap::{DUMMY_SP, dummy_spanned};
 use ext::base::ExtCtxt;
 use ext::expand::{Expansion, ExpansionKind};
+use ext::hygiene::Mark;
 use fold::*;
 use ptr::P;
-use symbol::{Symbol, keywords};
+use symbol::keywords;
 use util::move_map::MoveMap;
 use util::small_vector::SmallVector;
 
@@ -68,10 +69,6 @@ pub fn placeholder(kind: ExpansionKind, id: ast::NodeId) -> Expansion {
     }
 }
 
-pub fn macro_scope_placeholder() -> Expansion {
-    placeholder(ExpansionKind::Items, ast::DUMMY_NODE_ID)
-}
-
 pub struct PlaceholderExpander<'a, 'b: 'a> {
     expansions: HashMap<ast::NodeId, Expansion>,
     cx: &'a mut ExtCtxt<'b>,
@@ -100,11 +97,12 @@ impl<'a, 'b> PlaceholderExpander<'a, 'b> {
 impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
     fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
         match item.node {
-            // Scope placeholder
-            ast::ItemKind::Mac(_) if item.id == ast::DUMMY_NODE_ID => SmallVector::one(item),
-            ast::ItemKind::Mac(_) => self.remove(item.id).make_items(),
-            _ => noop_fold_item(item, self),
+            ast::ItemKind::Mac(ref mac) if !mac.node.path.segments.is_empty() => {}
+            ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
+            _ => {}
         }
+
+        noop_fold_item(item, self)
     }
 
     fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
@@ -172,10 +170,10 @@ impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
             block.stmts = block.stmts.move_flat_map(|mut stmt| {
                 remaining_stmts -= 1;
 
-                // Scope placeholder
+                // `macro_rules!` macro definition
                 if let ast::StmtKind::Item(ref item) = stmt.node {
-                    if let ast::ItemKind::Mac(..) = item.node {
-                        macros.push(item.ident.ctxt.data().outer_mark);
+                    if let ast::ItemKind::Mac(_) = item.node {
+                        macros.push(Mark::from_placeholder_id(item.id));
                         return None;
                     }
                 }
@@ -208,33 +206,13 @@ impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
     fn fold_mod(&mut self, module: ast::Mod) -> ast::Mod {
         let mut module = noop_fold_mod(module, self);
         module.items = module.items.move_flat_map(|item| match item.node {
-            ast::ItemKind::Mac(_) => None, // remove scope placeholders from modules
+            ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => None, // remove macro definitions
             _ => Some(item),
         });
         module
     }
-}
 
-pub fn reconstructed_macro_rules(def: &ast::MacroDef) -> Expansion {
-    Expansion::Items(SmallVector::one(P(ast::Item {
-        ident: def.ident,
-        attrs: def.attrs.clone(),
-        id: ast::DUMMY_NODE_ID,
-        node: ast::ItemKind::Mac(ast::Mac {
-            span: def.span,
-            node: ast::Mac_ {
-                path: ast::Path {
-                    span: DUMMY_SP,
-                    global: false,
-                    segments: vec![ast::PathSegment {
-                        identifier: ast::Ident::with_empty_ctxt(Symbol::intern("macro_rules")),
-                        parameters: ast::PathParameters::none(),
-                    }],
-                },
-                tts: def.body.clone(),
-            }
-        }),
-        vis: ast::Visibility::Inherited,
-        span: def.span,
-    })))
+    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
+        mac
+    }
 }

src/libsyntax/ext/tt/macro_rules.rs

@@ -10,10 +10,9 @@
 
 use {ast, attr};
 use syntax_pos::{Span, DUMMY_SP};
-use ext::base::{DummyResult, ExtCtxt, MacEager, MacResult, SyntaxExtension};
-use ext::base::{IdentMacroExpander, NormalTT, TTMacroExpander};
+use ext::base::{DummyResult, ExtCtxt, MacResult, SyntaxExtension};
+use ext::base::{NormalTT, TTMacroExpander};
 use ext::expand::{Expansion, ExpansionKind};
-use ext::placeholders;
 use ext::tt::macro_parser::{Success, Error, Failure};
 use ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
 use ext::tt::macro_parser::{parse, parse_failure_msg};
@@ -151,35 +150,6 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
     cx.span_fatal(best_fail_spot.substitute_dummy(sp), &best_fail_msg);
 }
 
-pub struct MacroRulesExpander;
-impl IdentMacroExpander for MacroRulesExpander {
-    fn expand(&self,
-              cx: &mut ExtCtxt,
-              span: Span,
-              ident: ast::Ident,
-              tts: Vec<tokenstream::TokenTree>,
-              attrs: Vec<ast::Attribute>)
-              -> Box<MacResult> {
-        let def = ast::MacroDef {
-            ident: ident,
-            id: ast::DUMMY_NODE_ID,
-            span: span,
-            body: tts,
-            attrs: attrs,
-        };
-
-        // If keep_macs is true, expands to a MacEager::items instead.
-        let result = if cx.ecfg.keep_macs {
-            MacEager::items(placeholders::reconstructed_macro_rules(&def).make_items())
-        } else {
-            MacEager::items(placeholders::macro_scope_placeholder().make_items())
-        };
-
-        cx.resolver.add_macro(cx.current_expansion.mark, def);
-        result
-    }
-}
-
 // Note that macro-by-example's input is also matched against a token tree:
 //                   $( $lhs:tt => $rhs:tt );+
 //

src/libsyntax_ext/lib.rs

@@ -50,8 +50,7 @@ pub mod deriving;
 
 use std::rc::Rc;
 use syntax::ast;
-use syntax::ext::base::{MacroExpanderFn, NormalTT, IdentTT, MultiModifier, NamedSyntaxExtension};
-use syntax::ext::tt::macro_rules::MacroRulesExpander;
+use syntax::ext::base::{MacroExpanderFn, NormalTT, MultiModifier, NamedSyntaxExtension};
 use syntax::symbol::Symbol;
 
 pub fn register_builtins(resolver: &mut syntax::ext::base::Resolver,
@@ -61,8 +60,6 @@ pub fn register_builtins(resolver: &mut syntax::ext::base::Resolver,
         resolver.add_ext(ast::Ident::with_empty_ctxt(name), Rc::new(ext));
     };
 
-    register(Symbol::intern("macro_rules"), IdentTT(Box::new(MacroRulesExpander), None, false));
-
     macro_rules! register {
         ($( $name:ident: $f:expr, )*) => { $(
             register(Symbol::intern(stringify!($name)),