Remove MacroRulesTT.

src/librustc_plugin/registry.rs

@@ -17,7 +17,7 @@ use rustc::mir::transform::MirMapPass;
 
 use syntax::ext::base::{SyntaxExtension, NamedSyntaxExtension, NormalTT};
 use syntax::ext::base::{IdentTT, MultiModifier, MultiDecorator};
-use syntax::ext::base::{MacroExpanderFn, MacroRulesTT};
+use syntax::ext::base::MacroExpanderFn;
 use syntax::parse::token;
 use syntax::ast;
 use syntax::feature_gate::AttributeType;
@@ -111,10 +111,6 @@ impl<'a> Registry<'a> {
             }
             MultiDecorator(ext) => MultiDecorator(ext),
             MultiModifier(ext) => MultiModifier(ext),
-            MacroRulesTT => {
-                self.sess.err("plugin tried to register a new MacroRulesTT");
-                return;
-            }
         }));
     }
 

src/libsyntax/ext/base.rs

@@ -457,9 +457,6 @@ pub enum SyntaxExtension {
     /// the block.
     ///
     IdentTT(Box<IdentMacroExpander + 'static>, Option<Span>, bool),
-
-    /// Represents `macro_rules!` itself.
-    MacroRulesTT,
 }
 
 pub type NamedSyntaxExtension = (Name, SyntaxExtension);

src/libsyntax/ext/expand.rs

@@ -12,7 +12,7 @@ use ast::{Block, Crate, Ident, Mac_, PatKind};
 use ast::{MacStmtStyle, StmtKind, ItemKind};
 use ast;
 use ext::hygiene::Mark;
-use ext::placeholders::{self, placeholder, PlaceholderExpander};
+use ext::placeholders::{placeholder, PlaceholderExpander};
 use attr::{self, HasAttrs};
 use codemap::{ExpnInfo, NameAndSpan, MacroBang, MacroAttribute};
 use syntax_pos::{self, Span, ExpnId};
@@ -377,46 +377,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 kind.make_from(expander.expand(self.cx, span, ident, marked_tts, attrs))
             }
 
-            MacroRulesTT => {
-                if ident.name == keywords::Invalid.name() {
-                    self.cx.span_err(path.span,
-                                    &format!("macro {}! expects an ident argument", extname));
-                    return kind.dummy(span);
-                };
-
-                self.cx.bt_push(ExpnInfo {
-                    call_site: span,
-                    callee: NameAndSpan {
-                        format: MacroBang(extname),
-                        span: None,
-                        // `macro_rules!` doesn't directly allow unstable
-                        // (this is orthogonal to whether the macro it creates allows it)
-                        allow_internal_unstable: false,
-                    }
-                });
-
-                let def = ast::MacroDef {
-                    ident: ident,
-                    id: ast::DUMMY_NODE_ID,
-                    span: span,
-                    imported_from: None,
-                    use_locally: true,
-                    body: marked_tts,
-                    export: attr::contains_name(&attrs, "macro_export"),
-                    allow_internal_unstable: attr::contains_name(&attrs, "allow_internal_unstable"),
-                    attrs: attrs,
-                };
-
-                self.cx.insert_macro(def.clone());
-
-                // If keep_macs is true, expands to a MacEager::items instead.
-                if self.cx.ecfg.keep_macs {
-                    Some(placeholders::reconstructed_macro_rules(&def, &path))
-                } else {
-                    Some(placeholders::macro_scope_placeholder())
-                }
-            }
-
             MultiDecorator(..) | MultiModifier(..) => {
                 self.cx.span_err(path.span,
                                  &format!("`{}` can only be used in attributes", extname));

src/libsyntax/ext/placeholders.rs

@@ -13,7 +13,7 @@ use codemap::{DUMMY_SP, dummy_spanned};
 use ext::base::ExtCtxt;
 use ext::expand::{Expansion, ExpansionKind};
 use fold::*;
-use parse::token::keywords;
+use parse::token::{intern, keywords};
 use ptr::P;
 use util::move_map::MoveMap;
 use util::small_vector::SmallVector;
@@ -214,15 +214,22 @@ impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
     }
 }
 
-pub fn reconstructed_macro_rules(def: &ast::MacroDef, path: &ast::Path) -> Expansion {
+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: path.clone(),
+                path: ast::Path {
+                    span: DUMMY_SP,
+                    global: false,
+                    segments: vec![ast::PathSegment {
+                        identifier: ast::Ident::with_empty_ctxt(intern("macro_rules")),
+                        parameters: ast::PathParameters::none(),
+                    }],
+                },
                 tts: def.body.clone(),
             }
         }),

src/libsyntax/ext/tt/macro_rules.rs

@@ -8,10 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use ast;
+use {ast, attr};
 use syntax_pos::{Span, DUMMY_SP};
-use ext::base::{DummyResult, ExtCtxt, MacResult, SyntaxExtension};
-use ext::base::{NormalTT, TTMacroExpander};
+use ext::base::{DummyResult, ExtCtxt, MacEager, MacResult, SyntaxExtension};
+use ext::base::{IdentMacroExpander, NormalTT, TTMacroExpander};
+use ext::placeholders;
 use ext::tt::macro_parser::{Success, Error, Failure};
 use ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
 use ext::tt::macro_parser::parse;
@@ -242,6 +243,38 @@ 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,
+            imported_from: None,
+            use_locally: true,
+            body: tts,
+            export: attr::contains_name(&attrs, "macro_export"),
+            allow_internal_unstable: attr::contains_name(&attrs, "allow_internal_unstable"),
+            attrs: attrs,
+        };
+
+        cx.insert_macro(def.clone());
+
+        // If keep_macs is true, expands to a MacEager::items instead.
+        if cx.ecfg.keep_macs {
+            MacEager::items(placeholders::reconstructed_macro_rules(&def).make_items())
+        } else {
+            MacEager::items(placeholders::macro_scope_placeholder().make_items())
+        }
+    }
+}
+
 // Note that macro-by-example's input is also matched against a token tree:
 //                   $( $lhs:tt => $rhs:tt );+
 //

src/libsyntax_ext/lib.rs

@@ -50,16 +50,17 @@ pub mod deriving;
 
 use std::rc::Rc;
 use syntax::ast;
-use syntax::ext::base::{MacroExpanderFn, MacroRulesTT, NormalTT, MultiModifier};
+use syntax::ext::base::{MacroExpanderFn, NormalTT, IdentTT, MultiModifier};
 use syntax::ext::hygiene::Mark;
+use syntax::ext::tt::macro_rules::MacroRulesExpander;
 use syntax::parse::token::intern;
 
 pub fn register_builtins(resolver: &mut syntax::ext::base::Resolver, enable_quotes: bool) {
     let mut register = |name, ext| {
         resolver.add_macro(Mark::root(), ast::Ident::with_empty_ctxt(intern(name)), Rc::new(ext));
     };
 
-    register("macro_rules", MacroRulesTT);
+    register("macro_rules", IdentTT(Box::new(MacroRulesExpander), None, false));
 
     macro_rules! register {
         ($( $name:ident: $f:expr, )*) => { $(