src/librustc_resolve/build_reduced_graph.rs

   1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! Reduced graph building
  12 //!
  13 //! Here we build the "reduced graph": the graph of the module tree without
  14 //! any imports resolved.
  15
  16 use macros::{InvocationData, LegacyScope};
  17 use resolve_imports::ImportDirective;
  18 use resolve_imports::ImportDirectiveSubclass::{self, GlobImport, SingleImport};
  19 use {Module, ModuleData, ModuleKind, NameBinding, NameBindingKind, ToNameBinding};
  20 use {PerNS, Resolver, ResolverArenas};
  21 use Namespace::{self, TypeNS, ValueNS, MacroNS};
  22 use {resolve_error, resolve_struct_error, ResolutionError};
  23
  24 use rustc::middle::cstore::LoadedMacro;
  25 use rustc::hir::def::*;
  26 use rustc::hir::def_id::{BUILTIN_MACROS_CRATE, CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
  27 use rustc::ty;
  28
  29 use std::cell::Cell;
  30 use rustc_data_structures::sync::Lrc;
  31
  32 use syntax::ast::{Name, Ident};
  33 use syntax::attr;
  34
  35 use syntax::ast::{self, Block, ForeignItem, ForeignItemKind, Item, ItemKind, NodeId};
  36 use syntax::ast::{Mutability, StmtKind, TraitItem, TraitItemKind, Variant};
  37 use syntax::ext::base::{MacroKind, SyntaxExtension};
  38 use syntax::ext::base::Determinacy::Undetermined;
  39 use syntax::ext::hygiene::Mark;
  40 use syntax::ext::tt::macro_rules;
  41 use syntax::parse::token::{self, Token};
  42 use syntax::std_inject::injected_crate_name;
  43 use syntax::symbol::keywords;
  44 use syntax::visit::{self, Visitor};
  45
  46 use syntax_pos::{Span, DUMMY_SP};
  47
  48 impl<'a> ToNameBinding<'a> for (Module<'a>, ty::Visibility, Span, Mark) {
  49     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
  50         arenas.alloc_name_binding(NameBinding {
  51             kind: NameBindingKind::Module(self.0),
  52             vis: self.1,
  53             span: self.2,
  54             expansion: self.3,
  55         })
  56     }
  57 }
  58
  59 impl<'a> ToNameBinding<'a> for (Def, ty::Visibility, Span, Mark) {
  60     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
  61         arenas.alloc_name_binding(NameBinding {
  62             kind: NameBindingKind::Def(self.0, false),
  63             vis: self.1,
  64             span: self.2,
  65             expansion: self.3,
  66         })
  67     }
  68 }
  69
  70 pub(crate) struct IsMacroExport;
  71
  72 impl<'a> ToNameBinding<'a> for (Def, ty::Visibility, Span, Mark, IsMacroExport) {
  73     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
  74         arenas.alloc_name_binding(NameBinding {
  75             kind: NameBindingKind::Def(self.0, true),
  76             vis: self.1,
  77             span: self.2,
  78             expansion: self.3,
  79         })
  80     }
  81 }
  82
  83 #[derive(Default, PartialEq, Eq)]
  84 struct LegacyMacroImports {
  85     import_all: Option<Span>,
  86     imports: Vec<(Name, Span)>,
  87 }
  88
  89 impl<'a> Resolver<'a> {
  90     /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
  91     /// otherwise, reports an error.
  92     pub fn define<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
  93         where T: ToNameBinding<'a>,
  94     {
  95         let binding = def.to_name_binding(self.arenas);
  96         if let Err(old_binding) = self.try_define(parent, ident, ns, binding) {
  97             self.report_conflict(parent, ident, ns, old_binding, &binding);
  98         }
  99     }
 100
 101     fn block_needs_anonymous_module(&mut self, block: &Block) -> bool {
 102         // If any statements are items, we need to create an anonymous module
 103         block.stmts.iter().any(|statement| match statement.node {
 104             StmtKind::Item(_) | StmtKind::Mac(_) => true,
 105             _ => false,
 106         })
 107     }
 108
 109     fn insert_field_names(&mut self, def_id: DefId, field_names: Vec<Name>) {
 110         if !field_names.is_empty() {
 111             self.field_names.insert(def_id, field_names);
 112         }
 113     }
 114
 115     fn build_reduced_graph_for_use_tree(&mut self,
 116                                         root_use_tree: &ast::UseTree,
 117                                         root_id: NodeId,
 118                                         use_tree: &ast::UseTree,
 119                                         id: NodeId,
 120                                         vis: ty::Visibility,
 121                                         prefix: &ast::Path,
 122                                         nested: bool,
 123                                         item: &Item,
 124                                         expansion: Mark) {
 125         let is_prelude = attr::contains_name(&item.attrs, "prelude_import");
 126         let path = &use_tree.prefix;
 127
 128         let mut module_path: Vec<_> = prefix.segments.iter()
 129             .chain(path.segments.iter())
 130             .map(|seg| seg.ident)
 131             .collect();
 132
 133         match use_tree.kind {
 134             ast::UseTreeKind::Simple(rename, ..) => {
 135                 let mut ident = use_tree.ident();
 136                 let mut source = module_path.pop().unwrap();
 137                 let mut type_ns_only = false;
 138
 139                 if nested {
 140                     // Correctly handle `self`
 141                     if source.name == keywords::SelfValue.name() {
 142                         type_ns_only = true;
 143
 144                         let last_segment = *module_path.last().unwrap();
 145                         if last_segment.name == keywords::CrateRoot.name() {
 146                             resolve_error(
 147                                 self,
 148                                 use_tree.span,
 149                                 ResolutionError::
 150                                 SelfImportOnlyInImportListWithNonEmptyPrefix
 151                             );
 152                             return;
 153                         }
 154
 155                         // Replace `use foo::self;` with `use foo;`
 156                         let _ = module_path.pop();
 157                         source = last_segment;
 158                         if rename.is_none() {
 159                             ident = last_segment;
 160                         }
 161                     }
 162                 } else {
 163                     // Disallow `self`
 164                     if source.name == keywords::SelfValue.name() {
 165                         resolve_error(self,
 166                                       use_tree.span,
 167                                       ResolutionError::SelfImportsOnlyAllowedWithin);
 168                     }
 169
 170                     // Disallow `use $crate;`
 171                     if source.name == keywords::DollarCrate.name() && path.segments.len() == 1 {
 172                         let crate_root = self.resolve_crate_root(source);
 173                         let crate_name = match crate_root.kind {
 174                             ModuleKind::Def(_, name) => name,
 175                             ModuleKind::Block(..) => unreachable!(),
 176                         };
 177                         source.name = crate_name;
 178                         if rename.is_none() {
 179                             ident.name = crate_name;
 180                         }
 181
 182                         self.session.struct_span_warn(item.span, "`$crate` may not be imported")
 183                             .note("`use $crate;` was erroneously allowed and \
 184                                    will become a hard error in a future release")
 185                             .emit();
 186                     }
 187                 }
 188
 189                 let subclass = SingleImport {
 190                     target: ident,
 191                     source,
 192                     result: PerNS {
 193                         type_ns: Cell::new(Err(Undetermined)),
 194                         value_ns: Cell::new(Err(Undetermined)),
 195                         macro_ns: Cell::new(Err(Undetermined)),
 196                     },
 197                     type_ns_only,
 198                 };
 199                 self.add_import_directive(
 200                     module_path,
 201                     subclass,
 202                     use_tree.span,
 203                     id,
 204                     root_use_tree.span,
 205                     root_id,
 206                     vis,
 207                     expansion,
 208                 );
 209             }
 210             ast::UseTreeKind::Glob => {
 211                 let subclass = GlobImport {
 212                     is_prelude,
 213                     max_vis: Cell::new(ty::Visibility::Invisible),
 214                 };
 215                 self.add_import_directive(
 216                     module_path,
 217                     subclass,
 218                     use_tree.span,
 219                     id,
 220                     root_use_tree.span,
 221                     root_id,
 222                     vis,
 223                     expansion,
 224                 );
 225             }
 226             ast::UseTreeKind::Nested(ref items) => {
 227                 let prefix = ast::Path {
 228                     segments: module_path.into_iter()
 229                         .map(|ident| ast::PathSegment::from_ident(ident))
 230                         .collect(),
 231                     span: path.span,
 232                 };
 233
 234                 // Ensure there is at most one `self` in the list
 235                 let self_spans = items.iter().filter_map(|&(ref use_tree, _)| {
 236                     if let ast::UseTreeKind::Simple(..) = use_tree.kind {
 237                         if use_tree.ident().name == keywords::SelfValue.name() {
 238                             return Some(use_tree.span);
 239                         }
 240                     }
 241
 242                     None
 243                 }).collect::<Vec<_>>();
 244                 if self_spans.len() > 1 {
 245                     let mut e = resolve_struct_error(self,
 246                         self_spans[0],
 247                         ResolutionError::SelfImportCanOnlyAppearOnceInTheList);
 248
 249                     for other_span in self_spans.iter().skip(1) {
 250                         e.span_label(*other_span, "another `self` import appears here");
 251                     }
 252
 253                     e.emit();
 254                 }
 255
 256                 for &(ref tree, id) in items {
 257                     self.build_reduced_graph_for_use_tree(
 258                         root_use_tree, root_id, tree, id, vis, &prefix, true, item, expansion
 259                     );
 260                 }
 261             }
 262         }
 263     }
 264
 265     /// Constructs the reduced graph for one item.
 266     fn build_reduced_graph_for_item(&mut self, item: &Item, expansion: Mark) {
 267         let parent = self.current_module;
 268         let ident = item.ident;
 269         let sp = item.span;
 270         let vis = self.resolve_visibility(&item.vis);
 271
 272         match item.node {
 273             ItemKind::Use(ref use_tree) => {
 274                 // Imports are resolved as global by default, add starting root segment.
 275                 let prefix = ast::Path {
 276                     segments: use_tree.prefix.make_root().into_iter().collect(),
 277                     span: use_tree.span,
 278                 };
 279
 280                 self.build_reduced_graph_for_use_tree(
 281                     use_tree, item.id, use_tree, item.id, vis, &prefix, false, item, expansion,
 282                 );
 283             }
 284
 285             ItemKind::ExternCrate(orig_name) => {
 286                 let crate_id = self.crate_loader.process_extern_crate(item, &self.definitions);
 287                 let module =
 288                     self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
 289                 self.populate_module_if_necessary(module);
 290                 if injected_crate_name().map_or(false, |name| item.ident.name == name) {
 291                     self.injected_crate = Some(module);
 292                 }
 293
 294                 let used = self.process_legacy_macro_imports(item, module, expansion);
 295                 let binding =
 296                     (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.arenas);
 297                 let directive = self.arenas.alloc_import_directive(ImportDirective {
 298                     root_id: item.id,
 299                     id: item.id,
 300                     parent,
 301                     imported_module: Cell::new(Some(module)),
 302                     subclass: ImportDirectiveSubclass::ExternCrate(orig_name),
 303                     root_span: item.span,
 304                     span: item.span,
 305                     module_path: Vec::new(),
 306                     vis: Cell::new(vis),
 307                     expansion,
 308                     used: Cell::new(used),
 309                 });
 310                 self.potentially_unused_imports.push(directive);
 311                 let imported_binding = self.import(binding, directive);
 312                 self.define(parent, ident, TypeNS, imported_binding);
 313             }
 314
 315             ItemKind::GlobalAsm(..) => {}
 316
 317             ItemKind::Mod(..) if item.ident == keywords::Invalid.ident() => {} // Crate root
 318
 319             ItemKind::Mod(..) => {
 320                 let def_id = self.definitions.local_def_id(item.id);
 321                 let module_kind = ModuleKind::Def(Def::Mod(def_id), ident.name);
 322                 let module = self.arenas.alloc_module(ModuleData {
 323                     no_implicit_prelude: parent.no_implicit_prelude || {
 324                         attr::contains_name(&item.attrs, "no_implicit_prelude")
 325                     },
 326                     ..ModuleData::new(Some(parent), module_kind, def_id, expansion, item.span)
 327                 });
 328                 self.define(parent, ident, TypeNS, (module, vis, sp, expansion));
 329                 self.module_map.insert(def_id, module);
 330
 331                 // Descend into the module.
 332                 self.current_module = module;
 333             }
 334
 335             // Handled in `rustc_metadata::{native_libs,link_args}`
 336             ItemKind::ForeignMod(..) => {}
 337
 338             // These items live in the value namespace.
 339             ItemKind::Static(_, m, _) => {
 340                 let mutbl = m == Mutability::Mutable;
 341                 let def = Def::Static(self.definitions.local_def_id(item.id), mutbl);
 342                 self.define(parent, ident, ValueNS, (def, vis, sp, expansion));
 343             }
 344             ItemKind::Const(..) => {
 345                 let def = Def::Const(self.definitions.local_def_id(item.id));
 346                 self.define(parent, ident, ValueNS, (def, vis, sp, expansion));
 347             }
 348             ItemKind::Fn(..) => {
 349                 let def = Def::Fn(self.definitions.local_def_id(item.id));
 350                 self.define(parent, ident, ValueNS, (def, vis, sp, expansion));
 351
 352                 // Functions introducing procedural macros reserve a slot
 353                 // in the macro namespace as well (see #52225).
 354                 if attr::contains_name(&item.attrs, "proc_macro") ||
 355                    attr::contains_name(&item.attrs, "proc_macro_attribute") {
 356                     let def = Def::Macro(def.def_id(), MacroKind::ProcMacroStub);
 357                     self.define(parent, ident, MacroNS, (def, vis, sp, expansion));
 358                 }
 359                 if let Some(attr) = attr::find_by_name(&item.attrs, "proc_macro_derive") {
 360                     if let Some(trait_attr) =
 361                             attr.meta_item_list().and_then(|list| list.get(0).cloned()) {
 362                         if let Some(ident) = trait_attr.name().map(Ident::with_empty_ctxt) {
 363                             let sp = trait_attr.span;
 364                             let def = Def::Macro(def.def_id(), MacroKind::ProcMacroStub);
 365                             self.define(parent, ident, MacroNS, (def, vis, sp, expansion));
 366                         }
 367                     }
 368                 }
 369             }
 370
 371             // These items live in the type namespace.
 372             ItemKind::Ty(..) => {
 373                 let def = Def::TyAlias(self.definitions.local_def_id(item.id));
 374                 self.define(parent, ident, TypeNS, (def, vis, sp, expansion));
 375             }
 376
 377             ItemKind::Existential(_, _) => {
 378                 let def = Def::Existential(self.definitions.local_def_id(item.id));
 379                 self.define(parent, ident, TypeNS, (def, vis, sp, expansion));
 380             }
 381
 382             ItemKind::Enum(ref enum_definition, _) => {
 383                 let def = Def::Enum(self.definitions.local_def_id(item.id));
 384                 let module_kind = ModuleKind::Def(def, ident.name);
 385                 let module = self.new_module(parent,
 386                                              module_kind,
 387                                              parent.normal_ancestor_id,
 388                                              expansion,
 389                                              item.span);
 390                 self.define(parent, ident, TypeNS, (module, vis, sp, expansion));
 391
 392                 for variant in &(*enum_definition).variants {
 393                     self.build_reduced_graph_for_variant(variant, module, vis, expansion);
 394                 }
 395             }
 396
 397             ItemKind::TraitAlias(..) => {
 398                 let def = Def::TraitAlias(self.definitions.local_def_id(item.id));
 399                 self.define(parent, ident, TypeNS, (def, vis, sp, expansion));
 400             }
 401
 402             // These items live in both the type and value namespaces.
 403             ItemKind::Struct(ref struct_def, _) => {
 404                 // Define a name in the type namespace.
 405                 let def_id = self.definitions.local_def_id(item.id);
 406                 let def = Def::Struct(def_id);
 407                 self.define(parent, ident, TypeNS, (def, vis, sp, expansion));
 408
 409                 let mut ctor_vis = vis;
 410
 411                 let has_non_exhaustive = attr::contains_name(&item.attrs, "non_exhaustive");
 412
 413                 // If the structure is marked as non_exhaustive then lower the visibility
 414                 // to within the crate.
 415                 if has_non_exhaustive && vis == ty::Visibility::Public {
 416                     ctor_vis = ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX));
 417                 }
 418
 419                 // Record field names for error reporting.
 420                 let field_names = struct_def.fields().iter().filter_map(|field| {
 421                     let field_vis = self.resolve_visibility(&field.vis);
 422                     if ctor_vis.is_at_least(field_vis, &*self) {
 423                         ctor_vis = field_vis;
 424                     }
 425                     field.ident.map(|ident| ident.name)
 426                 }).collect();
 427                 let item_def_id = self.definitions.local_def_id(item.id);
 428                 self.insert_field_names(item_def_id, field_names);
 429
 430                 // If this is a tuple or unit struct, define a name
 431                 // in the value namespace as well.
 432                 if !struct_def.is_struct() {
 433                     let ctor_def = Def::StructCtor(self.definitions.local_def_id(struct_def.id()),
 434                                                    CtorKind::from_ast(struct_def));
 435                     self.define(parent, ident, ValueNS, (ctor_def, ctor_vis, sp, expansion));
 436                     self.struct_constructors.insert(def.def_id(), (ctor_def, ctor_vis));
 437                 }
 438             }
 439
 440             ItemKind::Union(ref vdata, _) => {
 441                 let def = Def::Union(self.definitions.local_def_id(item.id));
 442                 self.define(parent, ident, TypeNS, (def, vis, sp, expansion));
 443
 444                 // Record field names for error reporting.
 445                 let field_names = vdata.fields().iter().filter_map(|field| {
 446                     self.resolve_visibility(&field.vis);
 447                     field.ident.map(|ident| ident.name)
 448                 }).collect();
 449                 let item_def_id = self.definitions.local_def_id(item.id);
 450                 self.insert_field_names(item_def_id, field_names);
 451             }
 452
 453             ItemKind::Impl(..) => {}
 454
 455             ItemKind::Trait(..) => {
 456                 let def_id = self.definitions.local_def_id(item.id);
 457
 458                 // Add all the items within to a new module.
 459                 let module_kind = ModuleKind::Def(Def::Trait(def_id), ident.name);
 460                 let module = self.new_module(parent,
 461                                              module_kind,
 462                                              parent.normal_ancestor_id,
 463                                              expansion,
 464                                              item.span);
 465                 self.define(parent, ident, TypeNS, (module, vis, sp, expansion));
 466                 self.current_module = module;
 467             }
 468
 469             ItemKind::MacroDef(..) | ItemKind::Mac(_) => unreachable!(),
 470         }
 471     }
 472
 473     // Constructs the reduced graph for one variant. Variants exist in the
 474     // type and value namespaces.
 475     fn build_reduced_graph_for_variant(&mut self,
 476                                        variant: &Variant,
 477                                        parent: Module<'a>,
 478                                        vis: ty::Visibility,
 479                                        expansion: Mark) {
 480         let ident = variant.node.ident;
 481         let def_id = self.definitions.local_def_id(variant.node.data.id());
 482
 483         // Define a name in the type namespace.
 484         let def = Def::Variant(def_id);
 485         self.define(parent, ident, TypeNS, (def, vis, variant.span, expansion));
 486
 487         // Define a constructor name in the value namespace.
 488         // Braced variants, unlike structs, generate unusable names in
 489         // value namespace, they are reserved for possible future use.
 490         let ctor_kind = CtorKind::from_ast(&variant.node.data);
 491         let ctor_def = Def::VariantCtor(def_id, ctor_kind);
 492
 493         self.define(parent, ident, ValueNS, (ctor_def, vis, variant.span, expansion));
 494     }
 495
 496     /// Constructs the reduced graph for one foreign item.
 497     fn build_reduced_graph_for_foreign_item(&mut self, item: &ForeignItem, expansion: Mark) {
 498         let (def, ns) = match item.node {
 499             ForeignItemKind::Fn(..) => {
 500                 (Def::Fn(self.definitions.local_def_id(item.id)), ValueNS)
 501             }
 502             ForeignItemKind::Static(_, m) => {
 503                 (Def::Static(self.definitions.local_def_id(item.id), m), ValueNS)
 504             }
 505             ForeignItemKind::Ty => {
 506                 (Def::TyForeign(self.definitions.local_def_id(item.id)), TypeNS)
 507             }
 508             ForeignItemKind::Macro(_) => unreachable!(),
 509         };
 510         let parent = self.current_module;
 511         let vis = self.resolve_visibility(&item.vis);
 512         self.define(parent, item.ident, ns, (def, vis, item.span, expansion));
 513     }
 514
 515     fn build_reduced_graph_for_block(&mut self, block: &Block, expansion: Mark) {
 516         let parent = self.current_module;
 517         if self.block_needs_anonymous_module(block) {
 518             let module = self.new_module(parent,
 519                                          ModuleKind::Block(block.id),
 520                                          parent.normal_ancestor_id,
 521                                          expansion,
 522                                          block.span);
 523             self.block_map.insert(block.id, module);
 524             self.current_module = module; // Descend into the block.
 525         }
 526     }
 527
 528     /// Builds the reduced graph for a single item in an external crate.
 529     fn build_reduced_graph_for_external_crate_def(&mut self, parent: Module<'a>, child: Export) {
 530         let Export { ident, def, vis, span, .. } = child;
 531         let def_id = def.def_id();
 532         let expansion = Mark::root(); // FIXME(jseyfried) intercrate hygiene
 533         match def {
 534             Def::Mod(..) | Def::Enum(..) => {
 535                 let module = self.new_module(parent,
 536                                              ModuleKind::Def(def, ident.name),
 537                                              def_id,
 538                                              expansion,
 539                                              span);
 540                 self.define(parent, ident, TypeNS, (module, vis, DUMMY_SP, expansion));
 541             }
 542             Def::Variant(..) | Def::TyAlias(..) | Def::TyForeign(..) => {
 543                 self.define(parent, ident, TypeNS, (def, vis, DUMMY_SP, expansion));
 544             }
 545             Def::Fn(..) | Def::Static(..) | Def::Const(..) | Def::VariantCtor(..) => {
 546                 self.define(parent, ident, ValueNS, (def, vis, DUMMY_SP, expansion));
 547             }
 548             Def::StructCtor(..) => {
 549                 self.define(parent, ident, ValueNS, (def, vis, DUMMY_SP, expansion));
 550
 551                 if let Some(struct_def_id) =
 552                         self.cstore.def_key(def_id).parent
 553                             .map(|index| DefId { krate: def_id.krate, index: index }) {
 554                     self.struct_constructors.insert(struct_def_id, (def, vis));
 555                 }
 556             }
 557             Def::Trait(..) => {
 558                 let module_kind = ModuleKind::Def(def, ident.name);
 559                 let module = self.new_module(parent,
 560                                              module_kind,
 561                                              parent.normal_ancestor_id,
 562                                              expansion,
 563                                              span);
 564                 self.define(parent, ident, TypeNS, (module, vis, DUMMY_SP, expansion));
 565
 566                 for child in self.cstore.item_children_untracked(def_id, self.session) {
 567                     let ns = if let Def::AssociatedTy(..) = child.def { TypeNS } else { ValueNS };
 568                     self.define(module, child.ident, ns,
 569                                 (child.def, ty::Visibility::Public, DUMMY_SP, expansion));
 570
 571                     if self.cstore.associated_item_cloned_untracked(child.def.def_id())
 572                            .method_has_self_argument {
 573                         self.has_self.insert(child.def.def_id());
 574                     }
 575                 }
 576                 module.populated.set(true);
 577             }
 578             Def::Struct(..) | Def::Union(..) => {
 579                 self.define(parent, ident, TypeNS, (def, vis, DUMMY_SP, expansion));
 580
 581                 // Record field names for error reporting.
 582                 let field_names = self.cstore.struct_field_names_untracked(def_id);
 583                 self.insert_field_names(def_id, field_names);
 584             }
 585             Def::Macro(..) => {
 586                 self.define(parent, ident, MacroNS, (def, vis, DUMMY_SP, expansion));
 587             }
 588             _ => bug!("unexpected definition: {:?}", def)
 589         }
 590     }
 591
 592     pub fn get_module(&mut self, def_id: DefId) -> Module<'a> {
 593         if def_id.krate == LOCAL_CRATE {
 594             return self.module_map[&def_id]
 595         }
 596
 597         let macros_only = self.cstore.dep_kind_untracked(def_id.krate).macros_only();
 598         if let Some(&module) = self.extern_module_map.get(&(def_id, macros_only)) {
 599             return module;
 600         }
 601
 602         let (name, parent) = if def_id.index == CRATE_DEF_INDEX {
 603             (self.cstore.crate_name_untracked(def_id.krate).as_interned_str(), None)
 604         } else {
 605             let def_key = self.cstore.def_key(def_id);
 606             (def_key.disambiguated_data.data.get_opt_name().unwrap(),
 607              Some(self.get_module(DefId { index: def_key.parent.unwrap(), ..def_id })))
 608         };
 609
 610         let kind = ModuleKind::Def(Def::Mod(def_id), name.as_symbol());
 611         let module =
 612             self.arenas.alloc_module(ModuleData::new(parent, kind, def_id, Mark::root(), DUMMY_SP));
 613         self.extern_module_map.insert((def_id, macros_only), module);
 614         module
 615     }
 616
 617     pub fn macro_def_scope(&mut self, expansion: Mark) -> Module<'a> {
 618         let def_id = self.macro_defs[&expansion];
 619         if let Some(id) = self.definitions.as_local_node_id(def_id) {
 620             self.local_macro_def_scopes[&id]
 621         } else if def_id.krate == BUILTIN_MACROS_CRATE {
 622             self.injected_crate.unwrap_or(self.graph_root)
 623         } else {
 624             let module_def_id = ty::DefIdTree::parent(&*self, def_id).unwrap();
 625             self.get_module(module_def_id)
 626         }
 627     }
 628
 629     pub fn get_macro(&mut self, def: Def) -> Lrc<SyntaxExtension> {
 630         let def_id = match def {
 631             Def::Macro(def_id, ..) => def_id,
 632             _ => panic!("Expected Def::Macro(..)"),
 633         };
 634         if let Some(ext) = self.macro_map.get(&def_id) {
 635             return ext.clone();
 636         }
 637
 638         let macro_def = match self.cstore.load_macro_untracked(def_id, &self.session) {
 639             LoadedMacro::MacroDef(macro_def) => macro_def,
 640             LoadedMacro::ProcMacro(ext) => return ext,
 641         };
 642
 643         let ext = Lrc::new(macro_rules::compile(&self.session.parse_sess,
 644                                                &self.session.features_untracked(),
 645                                                &macro_def,
 646                                                self.cstore.crate_edition_untracked(def_id.krate)));
 647         self.macro_map.insert(def_id, ext.clone());
 648         ext
 649     }
 650
 651     /// Ensures that the reduced graph rooted at the given external module
 652     /// is built, building it if it is not.
 653     pub fn populate_module_if_necessary(&mut self, module: Module<'a>) {
 654         if module.populated.get() { return }
 655         let def_id = module.def_id().unwrap();
 656         for child in self.cstore.item_children_untracked(def_id, self.session) {
 657             self.build_reduced_graph_for_external_crate_def(module, child);
 658         }
 659         module.populated.set(true)
 660     }
 661
 662     fn legacy_import_macro(&mut self,
 663                            name: Name,
 664                            binding: &'a NameBinding<'a>,
 665                            span: Span,
 666                            allow_shadowing: bool) {
 667         if self.macro_prelude.insert(name, binding).is_some() && !allow_shadowing {
 668             let msg = format!("`{}` is already in scope", name);
 669             let note =
 670                 "macro-expanded `#[macro_use]`s may not shadow existing macros (see RFC 1560)";
 671             self.session.struct_span_err(span, &msg).note(note).emit();
 672         }
 673     }
 674
 675     // This returns true if we should consider the underlying `extern crate` to be used.
 676     fn process_legacy_macro_imports(&mut self, item: &Item, module: Module<'a>, expansion: Mark)
 677                                     -> bool {
 678         let allow_shadowing = expansion == Mark::root();
 679         let legacy_imports = self.legacy_macro_imports(&item.attrs);
 680         let mut used = legacy_imports != LegacyMacroImports::default();
 681
 682         // `#[macro_use]` is only allowed at the crate root.
 683         if self.current_module.parent.is_some() && used {
 684             span_err!(self.session, item.span, E0468,
 685                       "an `extern crate` loading macros must be at the crate root");
 686         } else if !self.use_extern_macros && !used &&
 687                   self.cstore.dep_kind_untracked(module.def_id().unwrap().krate)
 688                       .macros_only() {
 689             let msg = "proc macro crates and `#[no_link]` crates have no effect without \
 690                        `#[macro_use]`";
 691             self.session.span_warn(item.span, msg);
 692             used = true; // Avoid the normal unused extern crate warning
 693         }
 694
 695         let (graph_root, arenas) = (self.graph_root, self.arenas);
 696         let macro_use_directive = |span| arenas.alloc_import_directive(ImportDirective {
 697             root_id: item.id,
 698             id: item.id,
 699             parent: graph_root,
 700             imported_module: Cell::new(Some(module)),
 701             subclass: ImportDirectiveSubclass::MacroUse,
 702             root_span: span,
 703             span,
 704             module_path: Vec::new(),
 705             vis: Cell::new(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))),
 706             expansion,
 707             used: Cell::new(false),
 708         });
 709
 710         if let Some(span) = legacy_imports.import_all {
 711             let directive = macro_use_directive(span);
 712             self.potentially_unused_imports.push(directive);
 713             module.for_each_child(|ident, ns, binding| if ns == MacroNS {
 714                 let imported_binding = self.import(binding, directive);
 715                 self.legacy_import_macro(ident.name, imported_binding, span, allow_shadowing);
 716             });
 717         } else {
 718             for (name, span) in legacy_imports.imports {
 719                 let ident = Ident::with_empty_ctxt(name);
 720                 let result = self.resolve_ident_in_module(module, ident, MacroNS, false, span);
 721                 if let Ok(binding) = result {
 722                     let directive = macro_use_directive(span);
 723                     self.potentially_unused_imports.push(directive);
 724                     let imported_binding = self.import(binding, directive);
 725                     self.legacy_import_macro(name, imported_binding, span, allow_shadowing);
 726                 } else {
 727                     span_err!(self.session, span, E0469, "imported macro not found");
 728                 }
 729             }
 730         }
 731         used
 732     }
 733
 734     // does this attribute list contain "macro_use"?
 735     fn contains_macro_use(&mut self, attrs: &[ast::Attribute]) -> bool {
 736         for attr in attrs {
 737             if attr.check_name("macro_escape") {
 738                 let msg = "macro_escape is a deprecated synonym for macro_use";
 739                 let mut err = self.session.struct_span_warn(attr.span, msg);
 740                 if let ast::AttrStyle::Inner = attr.style {
 741                     err.help("consider an outer attribute, #[macro_use] mod ...").emit();
 742                 } else {
 743                     err.emit();
 744                 }
 745             } else if !attr.check_name("macro_use") {
 746                 continue;
 747             }
 748
 749             if !attr.is_word() {
 750                 self.session.span_err(attr.span, "arguments to macro_use are not allowed here");
 751             }
 752             return true;
 753         }
 754
 755         false
 756     }
 757
 758     fn legacy_macro_imports(&mut self, attrs: &[ast::Attribute]) -> LegacyMacroImports {
 759         let mut imports = LegacyMacroImports::default();
 760         for attr in attrs {
 761             if attr.check_name("macro_use") {
 762                 match attr.meta_item_list() {
 763                     Some(names) => for attr in names {
 764                         if let Some(word) = attr.word() {
 765                             imports.imports.push((word.name(), attr.span()));
 766                         } else {
 767                             span_err!(self.session, attr.span(), E0466, "bad macro import");
 768                         }
 769                     },
 770                     None => imports.import_all = Some(attr.span),
 771                 }
 772             }
 773         }
 774         imports
 775     }
 776 }
 777
 778 pub struct BuildReducedGraphVisitor<'a, 'b: 'a> {
 779     pub resolver: &'a mut Resolver<'b>,
 780     pub legacy_scope: LegacyScope<'b>,
 781     pub expansion: Mark,
 782 }
 783
 784 impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
 785     fn visit_invoc(&mut self, id: ast::NodeId) -> &'b InvocationData<'b> {
 786         let mark = id.placeholder_to_mark();
 787         self.resolver.current_module.unresolved_invocations.borrow_mut().insert(mark);
 788         self.resolver.unresolved_invocations_macro_export.insert(mark);
 789         let invocation = self.resolver.invocations[&mark];
 790         invocation.module.set(self.resolver.current_module);
 791         invocation.legacy_scope.set(self.legacy_scope);
 792         invocation
 793     }
 794 }
 795
 796 macro_rules! method {
 797     ($visit:ident: $ty:ty, $invoc:path, $walk:ident) => {
 798         fn $visit(&mut self, node: &'a $ty) {
 799             if let $invoc(..) = node.node {
 800                 self.visit_invoc(node.id);
 801             } else {
 802                 visit::$walk(self, node);
 803             }
 804         }
 805     }
 806 }
 807
 808 impl<'a, 'b> Visitor<'a> for BuildReducedGraphVisitor<'a, 'b> {
 809     method!(visit_impl_item: ast::ImplItem, ast::ImplItemKind::Macro, walk_impl_item);
 810     method!(visit_expr:      ast::Expr,     ast::ExprKind::Mac,       walk_expr);
 811     method!(visit_pat:       ast::Pat,      ast::PatKind::Mac,        walk_pat);
 812     method!(visit_ty:        ast::Ty,       ast::TyKind::Mac,         walk_ty);
 813
 814     fn visit_item(&mut self, item: &'a Item) {
 815         let macro_use = match item.node {
 816             ItemKind::MacroDef(..) => {
 817                 self.resolver.define_macro(item, self.expansion, &mut self.legacy_scope);
 818                 return
 819             }
 820             ItemKind::Mac(..) => {
 821                 self.legacy_scope = LegacyScope::Expansion(self.visit_invoc(item.id));
 822                 return
 823             }
 824             ItemKind::Mod(..) => self.resolver.contains_macro_use(&item.attrs),
 825             _ => false,
 826         };
 827
 828         let (parent, legacy_scope) = (self.resolver.current_module, self.legacy_scope);
 829         self.resolver.build_reduced_graph_for_item(item, self.expansion);
 830         visit::walk_item(self, item);
 831         self.resolver.current_module = parent;
 832         if !macro_use {
 833             self.legacy_scope = legacy_scope;
 834         }
 835     }
 836
 837     fn visit_stmt(&mut self, stmt: &'a ast::Stmt) {
 838         if let ast::StmtKind::Mac(..) = stmt.node {
 839             self.legacy_scope = LegacyScope::Expansion(self.visit_invoc(stmt.id));
 840         } else {
 841             visit::walk_stmt(self, stmt);
 842         }
 843     }
 844
 845     fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) {
 846         if let ForeignItemKind::Macro(_) = foreign_item.node {
 847             self.visit_invoc(foreign_item.id);
 848             return;
 849         }
 850
 851         self.resolver.build_reduced_graph_for_foreign_item(foreign_item, self.expansion);
 852         visit::walk_foreign_item(self, foreign_item);
 853     }
 854
 855     fn visit_block(&mut self, block: &'a Block) {
 856         let (parent, legacy_scope) = (self.resolver.current_module, self.legacy_scope);
 857         self.resolver.build_reduced_graph_for_block(block, self.expansion);
 858         visit::walk_block(self, block);
 859         self.resolver.current_module = parent;
 860         self.legacy_scope = legacy_scope;
 861     }
 862
 863     fn visit_trait_item(&mut self, item: &'a TraitItem) {
 864         let parent = self.resolver.current_module;
 865
 866         if let TraitItemKind::Macro(_) = item.node {
 867             self.visit_invoc(item.id);
 868             return
 869         }
 870
 871         // Add the item to the trait info.
 872         let item_def_id = self.resolver.definitions.local_def_id(item.id);
 873         let (def, ns) = match item.node {
 874             TraitItemKind::Const(..) => (Def::AssociatedConst(item_def_id), ValueNS),
 875             TraitItemKind::Method(ref sig, _) => {
 876                 if sig.decl.has_self() {
 877                     self.resolver.has_self.insert(item_def_id);
 878                 }
 879                 (Def::Method(item_def_id), ValueNS)
 880             }
 881             TraitItemKind::Type(..) => (Def::AssociatedTy(item_def_id), TypeNS),
 882             TraitItemKind::Macro(_) => bug!(),  // handled above
 883         };
 884
 885         let vis = ty::Visibility::Public;
 886         self.resolver.define(parent, item.ident, ns, (def, vis, item.span, self.expansion));
 887
 888         self.resolver.current_module = parent.parent.unwrap(); // nearest normal ancestor
 889         visit::walk_trait_item(self, item);
 890         self.resolver.current_module = parent;
 891     }
 892
 893     fn visit_token(&mut self, t: Token) {
 894         if let Token::Interpolated(nt) = t {
 895             match nt.0 {
 896                 token::NtExpr(ref expr) => {
 897                     if let ast::ExprKind::Mac(..) = expr.node {
 898                         self.visit_invoc(expr.id);
 899                     }
 900                 }
 901                 _ => {}
 902             }
 903         }
 904     }
 905 }