Improve $crate.

src/librustc_resolve/build_reduced_graph.rs

@@ -37,6 +37,7 @@ use syntax::ast::{self, Block, ForeignItem, ForeignItemKind, Item, ItemKind};
 use syntax::ast::{Mutability, StmtKind, TraitItem, TraitItemKind};
 use syntax::ast::{Variant, ViewPathGlob, ViewPathList, ViewPathSimple};
 use syntax::ext::base::{SyntaxExtension, Resolver as SyntaxResolver};
+use syntax::ext::expand::mark_tts;
 use syntax::ext::hygiene::Mark;
 use syntax::feature_gate::{self, emit_feature_err};
 use syntax::ext::tt::macro_rules;
@@ -207,11 +208,16 @@ impl<'b> Resolver<'b> {
                 };
 
                 let mut custom_derive_crate = false;
+                // The mark of the expansion that generates the loaded macros.
+                let mut opt_mark = None;
                 for loaded_macro in self.crate_loader.load_macros(item, is_crate_root) {
+                    let mark = opt_mark.unwrap_or_else(Mark::fresh);
+                    opt_mark = Some(mark);
                     match loaded_macro.kind {
                         LoadedMacroKind::Def(mut def) => {
                             if def.use_locally {
                                 self.macro_names.insert(def.ident.name);
+                                def.body = mark_tts(&def.body, mark);
                                 let ext = macro_rules::compile(&self.session.parse_sess, &def);
                                 import_macro(self, def.ident.name, ext, loaded_macro.import_site);
                             }
@@ -249,6 +255,17 @@ impl<'b> Resolver<'b> {
                     });
                     self.define(parent, name, TypeNS, (module, sp, vis));
 
+                    if let Some(mark) = opt_mark {
+                        let invocation = self.arenas.alloc_invocation_data(InvocationData {
+                            module: Cell::new(module),
+                            def_index: CRATE_DEF_INDEX,
+                            const_integer: false,
+                            legacy_scope: Cell::new(LegacyScope::Empty),
+                            expansion: Cell::new(LegacyScope::Empty),
+                        });
+                        self.invocations.insert(mark, invocation);
+                    }
+
                     self.populate_module_if_necessary(module);
                 } else if custom_derive_crate {
                     // Define an empty module

src/librustc_resolve/lib.rs

@@ -53,7 +53,7 @@ use rustc::ty;
 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
 use rustc::util::nodemap::{NodeMap, NodeSet, FnvHashMap, FnvHashSet};
 
-use syntax::ext::hygiene::Mark;
+use syntax::ext::hygiene::{Mark, SyntaxContext};
 use syntax::ast::{self, FloatTy};
 use syntax::ast::{CRATE_NODE_ID, Name, NodeId, Ident, IntTy, UintTy};
 use syntax::ext::base::SyntaxExtension;
@@ -1579,6 +1579,17 @@ impl<'a> Resolver<'a> {
     /// grammar: (SELF MOD_SEP ) ? (SUPER MOD_SEP) *
     fn resolve_module_prefix(&mut self, module_path: &[Ident], span: Option<Span>)
                              -> ResolveResult<ModulePrefixResult<'a>> {
+        if &*module_path[0].name.as_str() == "$crate" {
+            let mut ctxt = module_path[0].ctxt;
+            while ctxt.source().0 != SyntaxContext::empty() {
+                ctxt = ctxt.source().0;
+            }
+            let module = self.invocations[&ctxt.source().1].module.get();
+            let crate_root =
+                if module.def_id().unwrap().is_local() { self.graph_root } else { module };
+            return Success(PrefixFound(crate_root, 1))
+        }
+
         // Start at the current module if we see `self` or `super`, or at the
         // top of the crate otherwise.
         let mut i = match &*module_path[0].name.as_str() {

src/librustc_resolve/macros.rs

@@ -29,10 +29,10 @@ use syntax_pos::Span;
 #[derive(Clone)]
 pub struct InvocationData<'a> {
     pub module: Cell<Module<'a>>,
-    def_index: DefIndex,
+    pub def_index: DefIndex,
     // True if this expansion is in a `const_integer` position, for example `[u32; m!()]`.
     // c.f. `DefCollector::visit_ast_const_integer`.
-    const_integer: bool,
+    pub const_integer: bool,
     // The scope in which the invocation path is resolved.
     pub legacy_scope: Cell<LegacyScope<'a>>,
     // The smallest scope that includes this invocation's expansion,

src/librustdoc/html/highlight.rs

@@ -295,7 +295,9 @@ impl<'a> Classifier<'a> {
                     "Option" | "Result" => Class::PreludeTy,
                     "Some" | "None" | "Ok" | "Err" => Class::PreludeVal,
 
+                    "$crate" => Class::KeyWord,
                     _ if tas.tok.is_any_keyword() => Class::KeyWord,
+
                     _ => {
                         if self.in_macro_nonterminal {
                             self.in_macro_nonterminal = false;
@@ -310,9 +312,6 @@ impl<'a> Classifier<'a> {
                 }
             }
 
-            // Special macro vars are like keywords.
-            token::SpecialVarNt(_) => Class::KeyWord,
-
             token::Lifetime(..) => Class::Lifetime,
 
             token::Underscore | token::Eof | token::Interpolated(..) |

src/libsyntax/ext/expand.rs

@@ -939,6 +939,6 @@ impl Folder for Marker {
 }
 
 // apply a given mark to the given token trees. Used prior to expansion of a macro.
-fn mark_tts(tts: &[TokenTree], m: Mark) -> Vec<TokenTree> {
+pub fn mark_tts(tts: &[TokenTree], m: Mark) -> Vec<TokenTree> {
     noop_fold_tts(tts, &mut Marker{mark:m, expn_id: None})
 }

src/libsyntax/ext/tt/macro_rules.rs

@@ -58,7 +58,6 @@ impl<'a> ParserAnyMacro<'a> {
 
 struct MacroRulesMacroExpander {
     name: ast::Ident,
-    imported_from: Option<ast::Ident>,
     lhses: Vec<TokenTree>,
     rhses: Vec<TokenTree>,
     valid: bool,
@@ -76,7 +75,6 @@ impl TTMacroExpander for MacroRulesMacroExpander {
         generic_extension(cx,
                           sp,
                           self.name,
-                          self.imported_from,
                           arg,
                           &self.lhses,
                           &self.rhses)
@@ -87,7 +85,6 @@ impl TTMacroExpander for MacroRulesMacroExpander {
 fn generic_extension<'cx>(cx: &'cx ExtCtxt,
                           sp: Span,
                           name: ast::Ident,
-                          imported_from: Option<ast::Ident>,
                           arg: &[TokenTree],
                           lhses: &[TokenTree],
                           rhses: &[TokenTree])
@@ -116,10 +113,8 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
                     _ => cx.span_bug(sp, "malformed macro rhs"),
                 };
                 // rhs has holes ( `$id` and `$(...)` that need filled)
-                let trncbr = new_tt_reader(&cx.parse_sess.span_diagnostic,
-                                           Some(named_matches),
-                                           imported_from,
-                                           rhs);
+                let trncbr =
+                    new_tt_reader(&cx.parse_sess.span_diagnostic, Some(named_matches), rhs);
                 let mut p = Parser::new(cx.parse_sess(), cx.cfg().clone(), Box::new(trncbr));
                 p.directory = cx.current_expansion.module.directory.clone();
                 p.restrictions = match cx.current_expansion.no_noninline_mod {
@@ -223,7 +218,7 @@ pub fn compile(sess: &ParseSess, def: &ast::MacroDef) -> SyntaxExtension {
     ];
 
     // Parse the macro_rules! invocation (`none` is for no interpolations):
-    let arg_reader = new_tt_reader(&sess.span_diagnostic, None, None, def.body.clone());
+    let arg_reader = new_tt_reader(&sess.span_diagnostic, None, def.body.clone());
 
     let argument_map = match parse(sess, &Vec::new(), arg_reader, &argument_gram) {
         Success(m) => m,
@@ -269,7 +264,6 @@ pub fn compile(sess: &ParseSess, def: &ast::MacroDef) -> SyntaxExtension {
 
     let exp: Box<_> = Box::new(MacroRulesMacroExpander {
         name: def.ident,
-        imported_from: def.imported_from,
         lhses: lhses,
         rhses: rhses,
         valid: valid,

src/libsyntax/ext/tt/transcribe.rs

@@ -14,7 +14,7 @@ use syntax_pos::{Span, DUMMY_SP};
 use errors::{Handler, DiagnosticBuilder};
 use ext::tt::macro_parser::{NamedMatch, MatchedSeq, MatchedNonterminal};
 use parse::token::{DocComment, MatchNt, SubstNt};
-use parse::token::{Token, Interpolated, NtIdent, NtTT, SpecialMacroVar};
+use parse::token::{Token, Interpolated, NtIdent, NtTT};
 use parse::token;
 use parse::lexer::TokenAndSpan;
 use tokenstream::{self, TokenTree};
@@ -39,10 +39,7 @@ pub struct TtReader<'a> {
     stack: Vec<TtFrame>,
     /* for MBE-style macro transcription */
     interpolations: HashMap<Ident, Rc<NamedMatch>>,
-    imported_from: Option<Ident>,
 
-    // Some => return imported_from as the next token
-    crate_name_next: Option<Span>,
     repeat_idx: Vec<usize>,
     repeat_len: Vec<usize>,
     /* cached: */
@@ -59,10 +56,9 @@ pub struct TtReader<'a> {
 /// (and should) be None.
 pub fn new_tt_reader(sp_diag: &Handler,
                      interp: Option<HashMap<Ident, Rc<NamedMatch>>>,
-                     imported_from: Option<Ident>,
                      src: Vec<tokenstream::TokenTree>)
                      -> TtReader {
-    new_tt_reader_with_doc_flag(sp_diag, interp, imported_from, src, false)
+    new_tt_reader_with_doc_flag(sp_diag, interp, src, false)
 }
 
 /// The extra `desugar_doc_comments` flag enables reading doc comments
@@ -73,7 +69,6 @@ pub fn new_tt_reader(sp_diag: &Handler,
 /// (and should) be None.
 pub fn new_tt_reader_with_doc_flag(sp_diag: &Handler,
                                    interp: Option<HashMap<Ident, Rc<NamedMatch>>>,
-                                   imported_from: Option<Ident>,
                                    src: Vec<tokenstream::TokenTree>,
                                    desugar_doc_comments: bool)
                                    -> TtReader {
@@ -93,8 +88,6 @@ pub fn new_tt_reader_with_doc_flag(sp_diag: &Handler,
             None => HashMap::new(),
             Some(x) => x,
         },
-        imported_from: imported_from,
-        crate_name_next: None,
         repeat_idx: Vec::new(),
         repeat_len: Vec::new(),
         desugar_doc_comments: desugar_doc_comments,
@@ -189,14 +182,6 @@ pub fn tt_next_token(r: &mut TtReader) -> TokenAndSpan {
         sp: r.cur_span.clone(),
     };
     loop {
-        match r.crate_name_next.take() {
-            None => (),
-            Some(sp) => {
-                r.cur_span = sp;
-                r.cur_tok = token::Ident(r.imported_from.unwrap());
-                return ret_val;
-            },
-        }
         let should_pop = match r.stack.last() {
             None => {
                 assert_eq!(ret_val.tok, token::Eof);
@@ -346,18 +331,6 @@ pub fn tt_next_token(r: &mut TtReader) -> TokenAndSpan {
                    sep: None
                 });
             }
-            TokenTree::Token(sp, token::SpecialVarNt(SpecialMacroVar::CrateMacroVar)) => {
-                r.stack.last_mut().unwrap().idx += 1;
-
-                if r.imported_from.is_some() {
-                    r.cur_span = sp;
-                    r.cur_tok = token::ModSep;
-                    r.crate_name_next = Some(sp);
-                    return ret_val;
-                }
-
-                // otherwise emit nothing and proceed to the next token
-            }
             TokenTree::Token(sp, tok) => {
                 r.cur_span = sp;
                 r.cur_tok = tok;

src/libsyntax/parse/mod.rs

@@ -276,7 +276,7 @@ pub fn filemap_to_tts(sess: &ParseSess, filemap: Rc<FileMap>)
 pub fn tts_to_parser<'a>(sess: &'a ParseSess,
                          tts: Vec<tokenstream::TokenTree>,
                          cfg: ast::CrateConfig) -> Parser<'a> {
-    let trdr = lexer::new_tt_reader(&sess.span_diagnostic, None, None, tts);
+    let trdr = lexer::new_tt_reader(&sess.span_diagnostic, None, tts);
     let mut p = Parser::new(sess, cfg, Box::new(trdr));
     p.check_unknown_macro_variable();
     p

src/libsyntax/parse/parser.rs

@@ -48,8 +48,7 @@ use parse::classify;
 use parse::common::SeqSep;
 use parse::lexer::{Reader, TokenAndSpan};
 use parse::obsolete::ObsoleteSyntax;
-use parse::token::{self, intern, MatchNt, SubstNt, SpecialVarNt, InternedString};
-use parse::token::{keywords, SpecialMacroVar};
+use parse::token::{self, intern, keywords, MatchNt, SubstNt, InternedString};
 use parse::{new_sub_parser_from_file, ParseSess};
 use util::parser::{AssocOp, Fixity};
 use print::pprust;
@@ -2653,8 +2652,12 @@ impl<'a> Parser<'a> {
                                           num_captures: name_num
                                       })));
                 } else if self.token.is_keyword(keywords::Crate) {
+                    let ident = match self.token {
+                        token::Ident(id) => ast::Ident { name: token::intern("$crate"), ..id },
+                        _ => unreachable!(),
+                    };
                     self.bump();
-                    return Ok(TokenTree::Token(sp, SpecialVarNt(SpecialMacroVar::CrateMacroVar)));
+                    return Ok(TokenTree::Token(sp, token::Ident(ident)));
                 } else {
                     sp = mk_sp(sp.lo, self.span.hi);
                     self.parse_ident().unwrap_or_else(|mut e| {

src/libsyntax/parse/token.rs

@@ -52,21 +52,6 @@ pub enum DelimToken {
     NoDelim,
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
-pub enum SpecialMacroVar {
-    /// `$crate` will be filled in with the name of the crate a macro was
-    /// imported from, if any.
-    CrateMacroVar,
-}
-
-impl SpecialMacroVar {
-    pub fn as_str(self) -> &'static str {
-        match self {
-            SpecialMacroVar::CrateMacroVar => "crate",
-        }
-    }
-}
-
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
 pub enum Lit {
     Byte(ast::Name),
@@ -148,8 +133,6 @@ pub enum Token {
     // In right-hand-sides of MBE macros:
     /// A syntactic variable that will be filled in by macro expansion.
     SubstNt(ast::Ident),
-    /// A macro variable with special meaning.
-    SpecialVarNt(SpecialMacroVar),
 
     // Junk. These carry no data because we don't really care about the data
     // they *would* carry, and don't really want to allocate a new ident for

src/libsyntax/print/pprust.rs

@@ -285,8 +285,6 @@ pub fn token_to_string(tok: &Token) -> String {
         token::Comment              => "/* */".to_string(),
         token::Shebang(s)           => format!("/* shebang: {}*/", s),
 
-        token::SpecialVarNt(var)    => format!("${}", var.as_str()),
-
         token::Interpolated(ref nt) => match *nt {
             token::NtExpr(ref e)        => expr_to_string(&e),
             token::NtMeta(ref e)        => meta_item_to_string(&e),

src/libsyntax/tokenstream.rs

@@ -134,7 +134,6 @@ impl TokenTree {
                     AttrStyle::Inner => 3,
                 }
             }
-            TokenTree::Token(_, token::SpecialVarNt(..)) => 2,
             TokenTree::Token(_, token::MatchNt(..)) => 3,
             TokenTree::Token(_, token::Interpolated(Nonterminal::NtTT(..))) => 1,
             TokenTree::Delimited(_, ref delimed) => delimed.tts.len() + 2,
@@ -188,11 +187,6 @@ impl TokenTree {
                 }
                 delimed.tts[index - 1].clone()
             }
-            (&TokenTree::Token(sp, token::SpecialVarNt(var)), _) => {
-                let v = [TokenTree::Token(sp, token::Dollar),
-                         TokenTree::Token(sp, token::Ident(token::str_to_ident(var.as_str())))];
-                v[index].clone()
-            }
             (&TokenTree::Token(sp, token::MatchNt(name, kind)), _) => {
                 let v = [TokenTree::Token(sp, token::SubstNt(name)),
                          TokenTree::Token(sp, token::Colon),
@@ -223,7 +217,6 @@ impl TokenTree {
                  -> macro_parser::NamedParseResult {
         // `None` is because we're not interpolating
         let arg_rdr = lexer::new_tt_reader_with_doc_flag(&cx.parse_sess().span_diagnostic,
-                                                         None,
                                                          None,
                                                          tts.iter().cloned().collect(),
                                                          true);

src/test/pretty/issue-4264.pp

@@ -38,7 +38,7 @@
 
 
 
-    ((::std::fmt::format as
+    (($crate::fmt::format as
          fn(std::fmt::Arguments<'_>) -> std::string::String {std::fmt::format})(((::std::fmt::Arguments::new_v1
                                                                                      as
                                                                                      fn(&[&str], &[std::fmt::ArgumentV1<'_>]) -> std::fmt::Arguments<'_> {std::fmt::Arguments<'_>::new_v1})(({