1 //! After we obtain a fresh AST fragment from a macro, code in this module helps to integrate
2 //! that fragment into the module structures that are already partially built.
4 //! Items from the fragment are placed into modules,
5 //! unexpanded macros in the fragment are visited and registered.
6 //! Imports are also considered items and placed into modules here, but not resolved yet.
8 use crate::def_collector::collect_definitions;
9 use crate::imports::{Import, ImportKind};
10 use crate::macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
11 use crate::Namespace::{self, MacroNS, TypeNS, ValueNS};
12 use crate::{CrateLint, Determinacy, ExternPreludeEntry, Module, ModuleKind, ModuleOrUniformRoot};
13 use crate::{NameBinding, NameBindingKind, ParentScope, PathResult, PerNS, ResolutionError};
14 use crate::{Resolver, ResolverArenas, Segment, ToNameBinding, VisResolutionError};
16 use rustc_ast::visit::{self, AssocCtxt, Visitor};
17 use rustc_ast::{self as ast, AssocItem, AssocItemKind, MetaItemKind, StmtKind};
18 use rustc_ast::{Block, Fn, ForeignItem, ForeignItemKind, Impl, Item, ItemKind, NodeId};
19 use rustc_ast_lowering::ResolverAstLowering;
20 use rustc_attr as attr;
21 use rustc_data_structures::sync::Lrc;
22 use rustc_errors::{struct_span_err, Applicability};
23 use rustc_expand::base::SyntaxExtension;
24 use rustc_expand::expand::AstFragment;
25 use rustc_hir::def::{self, *};
26 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX};
27 use rustc_metadata::creader::LoadedMacro;
28 use rustc_middle::bug;
29 use rustc_middle::hir::exports::Export;
31 use rustc_session::cstore::CrateStore;
32 use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind};
33 use rustc_span::source_map::{respan, Spanned};
34 use rustc_span::symbol::{kw, sym, Ident, Symbol};
41 type Res = def::Res<NodeId>;
43 impl<'a> ToNameBinding<'a> for (Module<'a>, ty::Visibility, Span, LocalExpnId) {
44 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
45 arenas.alloc_name_binding(NameBinding {
46 kind: NameBindingKind::Module(self.0),
55 impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, LocalExpnId) {
56 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
57 arenas.alloc_name_binding(NameBinding {
58 kind: NameBindingKind::Res(self.0, false),
69 impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, LocalExpnId, IsMacroExport) {
70 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
71 arenas.alloc_name_binding(NameBinding {
72 kind: NameBindingKind::Res(self.0, true),
81 impl<'a> Resolver<'a> {
82 /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
83 /// otherwise, reports an error.
84 crate fn define<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
88 let binding = def.to_name_binding(self.arenas);
89 let key = self.new_key(ident, ns);
90 if let Err(old_binding) = self.try_define(parent, key, binding) {
91 self.report_conflict(parent, ident, ns, old_binding, &binding);
95 /// Walks up the tree of definitions starting at `def_id`,
96 /// stopping at the first encountered module.
97 /// Parent block modules for arbitrary def-ids are not recorded for the local crate,
98 /// and are not preserved in metadata for foreign crates, so block modules are never
99 /// returned by this function.
101 /// For the local crate ignoring block modules may be incorrect, so use this method with care.
103 /// For foreign crates block modules can be ignored without introducing observable differences,
104 /// moreover they has to be ignored right now because they are not kept in metadata.
105 /// Foreign parent modules are used for resolving names used by foreign macros with def-site
106 /// hygiene, therefore block module ignorability relies on macros with def-site hygiene and
107 /// block module parents being unreachable from other crates.
108 /// Reachable macros with block module parents exist due to `#[macro_export] macro_rules!`,
109 /// but they cannot use def-site hygiene, so the assumption holds
110 /// (<https://github.com/rust-lang/rust/pull/77984#issuecomment-712445508>).
111 fn get_nearest_non_block_module(&mut self, mut def_id: DefId) -> Module<'a> {
113 match self.get_module(def_id) {
114 Some(module) => return module,
117 self.def_key(def_id).parent.expect("non-root `DefId` without parent")
123 pub fn expect_module(&mut self, def_id: DefId) -> Module<'a> {
124 self.get_module(def_id).expect("argument `DefId` is not a module")
127 /// If `def_id` refers to a module (in resolver's sense, i.e. a module item, crate root, enum,
128 /// or trait), then this function returns that module's resolver representation, otherwise it
130 crate fn get_module(&mut self, def_id: DefId) -> Option<Module<'a>> {
131 if let module @ Some(..) = self.module_map.get(&def_id) {
132 return module.copied();
135 if !def_id.is_local() {
136 let def_kind = self.cstore().def_kind(def_id);
138 DefKind::Mod | DefKind::Enum | DefKind::Trait => {
139 let def_key = self.cstore().def_key(def_id);
140 let parent = def_key.parent.map(|index| {
141 self.get_nearest_non_block_module(DefId { index, krate: def_id.krate })
143 let name = if def_id.index == CRATE_DEF_INDEX {
144 self.cstore().crate_name(def_id.krate)
146 def_key.disambiguated_data.data.get_opt_name().expect("module without name")
149 Some(self.new_module(
151 ModuleKind::Def(def_kind, def_id, name),
152 self.cstore().module_expansion_untracked(def_id, &self.session),
153 self.cstore().get_span_untracked(def_id, &self.session),
154 // FIXME: Account for `#[no_implicit_prelude]` attributes.
155 parent.map_or(false, |module| module.no_implicit_prelude),
165 crate fn expn_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
166 match expn_id.expn_data().macro_def_id {
167 Some(def_id) => self.macro_def_scope(def_id),
170 .and_then(|expn_id| self.ast_transform_scopes.get(&expn_id))
171 .unwrap_or(&self.graph_root),
175 crate fn macro_def_scope(&mut self, def_id: DefId) -> Module<'a> {
176 if let Some(id) = def_id.as_local() {
177 self.local_macro_def_scopes[&id]
179 self.get_nearest_non_block_module(def_id)
183 crate fn get_macro(&mut self, res: Res) -> Option<Lrc<SyntaxExtension>> {
185 Res::Def(DefKind::Macro(..), def_id) => Some(self.get_macro_by_def_id(def_id)),
186 Res::NonMacroAttr(_) => Some(self.non_macro_attr.clone()),
191 crate fn get_macro_by_def_id(&mut self, def_id: DefId) -> Lrc<SyntaxExtension> {
192 if let Some(ext) = self.macro_map.get(&def_id) {
196 let ext = Lrc::new(match self.cstore().load_macro_untracked(def_id, &self.session) {
197 LoadedMacro::MacroDef(item, edition) => self.compile_macro(&item, edition),
198 LoadedMacro::ProcMacro(ext) => ext,
201 self.macro_map.insert(def_id, ext.clone());
205 crate fn build_reduced_graph(
207 fragment: &AstFragment,
208 parent_scope: ParentScope<'a>,
209 ) -> MacroRulesScopeRef<'a> {
210 collect_definitions(self, fragment, parent_scope.expansion);
211 let mut visitor = BuildReducedGraphVisitor { r: self, parent_scope };
212 fragment.visit_with(&mut visitor);
213 visitor.parent_scope.macro_rules
216 crate fn build_reduced_graph_external(&mut self, module: Module<'a>) {
217 for child in self.cstore().item_children_untracked(module.def_id(), self.session) {
218 let parent_scope = ParentScope::module(module, self);
219 BuildReducedGraphVisitor { r: self, parent_scope }
220 .build_reduced_graph_for_external_crate_res(child);
225 struct BuildReducedGraphVisitor<'a, 'b> {
226 r: &'b mut Resolver<'a>,
227 parent_scope: ParentScope<'a>,
230 impl<'a> AsMut<Resolver<'a>> for BuildReducedGraphVisitor<'a, '_> {
231 fn as_mut(&mut self) -> &mut Resolver<'a> {
236 impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
237 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
238 self.resolve_visibility_speculative(vis, false).unwrap_or_else(|err| {
239 self.r.report_vis_error(err);
240 ty::Visibility::Public
244 fn resolve_visibility_speculative<'ast>(
246 vis: &'ast ast::Visibility,
248 ) -> Result<ty::Visibility, VisResolutionError<'ast>> {
249 let parent_scope = &self.parent_scope;
251 ast::VisibilityKind::Public => Ok(ty::Visibility::Public),
252 ast::VisibilityKind::Crate(..) => {
253 Ok(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)))
255 ast::VisibilityKind::Inherited => {
256 Ok(match self.parent_scope.module.kind {
257 // Any inherited visibility resolved directly inside an enum or trait
258 // (i.e. variants, fields, and trait items) inherits from the visibility
259 // of the enum or trait.
260 ModuleKind::Def(DefKind::Enum | DefKind::Trait, def_id, _) => {
261 self.r.visibilities[&def_id.expect_local()]
263 // Otherwise, the visibility is restricted to the nearest parent `mod` item.
264 _ => ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod()),
267 ast::VisibilityKind::Restricted { ref path, id, .. } => {
268 // For visibilities we are not ready to provide correct implementation of "uniform
269 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
270 // On 2015 edition visibilities are resolved as crate-relative by default,
271 // so we are prepending a root segment if necessary.
272 let ident = path.segments.get(0).expect("empty path in visibility").ident;
273 let crate_root = if ident.is_path_segment_keyword() {
275 } else if ident.span.rust_2015() {
276 Some(Segment::from_ident(Ident::new(
278 path.span.shrink_to_lo().with_ctxt(ident.span.ctxt()),
281 return Err(VisResolutionError::Relative2018(ident.span, path));
284 let segments = crate_root
286 .chain(path.segments.iter().map(|seg| seg.into()))
287 .collect::<Vec<_>>();
288 let expected_found_error = |res| {
289 Err(VisResolutionError::ExpectedFound(
291 Segment::names_to_string(&segments),
295 match self.r.resolve_path(
301 CrateLint::SimplePath(id),
303 PathResult::Module(ModuleOrUniformRoot::Module(module)) => {
304 let res = module.res().expect("visibility resolved to unnamed block");
306 self.r.record_partial_res(id, PartialRes::new(res));
308 if module.is_normal() {
310 Ok(ty::Visibility::Public)
312 let vis = ty::Visibility::Restricted(res.def_id());
313 if self.r.is_accessible_from(vis, parent_scope.module) {
316 Err(VisResolutionError::AncestorOnly(path.span))
320 expected_found_error(res)
323 PathResult::Module(..) => Err(VisResolutionError::ModuleOnly(path.span)),
324 PathResult::NonModule(partial_res) => {
325 expected_found_error(partial_res.base_res())
327 PathResult::Failed { span, label, suggestion, .. } => {
328 Err(VisResolutionError::FailedToResolve(span, label, suggestion))
330 PathResult::Indeterminate => Err(VisResolutionError::Indeterminate(path.span)),
336 fn insert_field_names_local(&mut self, def_id: DefId, vdata: &ast::VariantData) {
337 let field_names = vdata
340 .map(|field| respan(field.span, field.ident.map_or(kw::Empty, |ident| ident.name)))
342 self.insert_field_names(def_id, field_names);
345 fn insert_field_names(&mut self, def_id: DefId, field_names: Vec<Spanned<Symbol>>) {
346 self.r.field_names.insert(def_id, field_names);
349 fn block_needs_anonymous_module(&mut self, block: &Block) -> bool {
350 // If any statements are items, we need to create an anonymous module
354 .any(|statement| matches!(statement.kind, StmtKind::Item(_) | StmtKind::MacCall(_)))
357 // Add an import to the current module.
360 module_path: Vec<Segment>,
361 kind: ImportKind<'a>,
369 let current_module = self.parent_scope.module;
370 let import = self.r.arenas.alloc_import(Import {
372 parent_scope: self.parent_scope,
374 imported_module: Cell::new(None),
378 use_span_with_attributes: item.span_with_attributes(),
379 has_attributes: !item.attrs.is_empty(),
383 used: Cell::new(false),
386 debug!("add_import({:?})", import);
388 self.r.indeterminate_imports.push(import);
390 // Don't add unresolved underscore imports to modules
391 ImportKind::Single { target: Ident { name: kw::Underscore, .. }, .. } => {}
392 ImportKind::Single { target, type_ns_only, .. } => {
393 self.r.per_ns(|this, ns| {
394 if !type_ns_only || ns == TypeNS {
395 let key = this.new_key(target, ns);
396 let mut resolution = this.resolution(current_module, key).borrow_mut();
397 resolution.add_single_import(import);
401 // We don't add prelude imports to the globs since they only affect lexical scopes,
402 // which are not relevant to import resolution.
403 ImportKind::Glob { is_prelude: true, .. } => {}
404 ImportKind::Glob { .. } => current_module.globs.borrow_mut().push(import),
409 fn build_reduced_graph_for_use_tree(
411 // This particular use tree
412 use_tree: &ast::UseTree,
414 parent_prefix: &[Segment],
416 // The whole `use` item
422 "build_reduced_graph_for_use_tree(parent_prefix={:?}, use_tree={:?}, nested={})",
423 parent_prefix, use_tree, nested
426 let mut prefix_iter = parent_prefix
429 .chain(use_tree.prefix.segments.iter().map(|seg| seg.into()))
432 // On 2015 edition imports are resolved as crate-relative by default,
433 // so prefixes are prepended with crate root segment if necessary.
434 // The root is prepended lazily, when the first non-empty prefix or terminating glob
435 // appears, so imports in braced groups can have roots prepended independently.
436 let is_glob = matches!(use_tree.kind, ast::UseTreeKind::Glob);
437 let crate_root = match prefix_iter.peek() {
438 Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.rust_2015() => {
439 Some(seg.ident.span.ctxt())
441 None if is_glob && use_tree.span.rust_2015() => Some(use_tree.span.ctxt()),
445 Segment::from_ident(Ident::new(
447 use_tree.prefix.span.shrink_to_lo().with_ctxt(ctxt),
451 let prefix = crate_root.into_iter().chain(prefix_iter).collect::<Vec<_>>();
452 debug!("build_reduced_graph_for_use_tree: prefix={:?}", prefix);
454 let empty_for_self = |prefix: &[Segment]| {
455 prefix.is_empty() || prefix.len() == 1 && prefix[0].ident.name == kw::PathRoot
457 match use_tree.kind {
458 ast::UseTreeKind::Simple(rename, ..) => {
459 let mut ident = use_tree.ident();
460 let mut module_path = prefix;
461 let mut source = module_path.pop().unwrap();
462 let mut type_ns_only = false;
465 // Correctly handle `self`
466 if source.ident.name == kw::SelfLower {
469 if empty_for_self(&module_path) {
472 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix,
477 // Replace `use foo::{ self };` with `use foo;`
478 source = module_path.pop().unwrap();
479 if rename.is_none() {
480 ident = source.ident;
485 if source.ident.name == kw::SelfLower {
486 let parent = module_path.last();
488 let span = match parent {
489 // only `::self` from `use foo::self as bar`
490 Some(seg) => seg.ident.span.shrink_to_hi().to(source.ident.span),
491 None => source.ident.span,
493 let span_with_rename = match rename {
494 // only `self as bar` from `use foo::self as bar`
495 Some(rename) => source.ident.span.to(rename.span),
496 None => source.ident.span,
500 ResolutionError::SelfImportsOnlyAllowedWithin {
501 root: parent.is_none(),
506 // Error recovery: replace `use foo::self;` with `use foo;`
507 if let Some(parent) = module_path.pop() {
509 if rename.is_none() {
510 ident = source.ident;
515 // Disallow `use $crate;`
516 if source.ident.name == kw::DollarCrate && module_path.is_empty() {
517 let crate_root = self.r.resolve_crate_root(source.ident);
518 let crate_name = match crate_root.kind {
519 ModuleKind::Def(.., name) => name,
520 ModuleKind::Block(..) => unreachable!(),
522 // HACK(eddyb) unclear how good this is, but keeping `$crate`
523 // in `source` breaks `src/test/ui/imports/import-crate-var.rs`,
524 // while the current crate doesn't have a valid `crate_name`.
525 if crate_name != kw::Empty {
526 // `crate_name` should not be interpreted as relative.
527 module_path.push(Segment {
528 ident: Ident { name: kw::PathRoot, span: source.ident.span },
529 id: Some(self.r.next_node_id()),
530 has_generic_args: false,
532 source.ident.name = crate_name;
534 if rename.is_none() {
535 ident.name = crate_name;
540 .struct_span_err(item.span, "`$crate` may not be imported")
545 if ident.name == kw::Crate {
546 self.r.session.span_err(
548 "crate root imports need to be explicitly named: \
549 `use crate as name;`",
553 let kind = ImportKind::Single {
554 source: source.ident,
556 source_bindings: PerNS {
557 type_ns: Cell::new(Err(Determinacy::Undetermined)),
558 value_ns: Cell::new(Err(Determinacy::Undetermined)),
559 macro_ns: Cell::new(Err(Determinacy::Undetermined)),
561 target_bindings: PerNS {
562 type_ns: Cell::new(None),
563 value_ns: Cell::new(None),
564 macro_ns: Cell::new(None),
580 ast::UseTreeKind::Glob => {
581 let kind = ImportKind::Glob {
582 is_prelude: self.r.session.contains_name(&item.attrs, sym::prelude_import),
583 max_vis: Cell::new(ty::Visibility::Invisible),
585 self.add_import(prefix, kind, use_tree.span, id, item, root_span, item.id, vis);
587 ast::UseTreeKind::Nested(ref items) => {
588 // Ensure there is at most one `self` in the list
589 let self_spans = items
591 .filter_map(|&(ref use_tree, _)| {
592 if let ast::UseTreeKind::Simple(..) = use_tree.kind {
593 if use_tree.ident().name == kw::SelfLower {
594 return Some(use_tree.span);
600 .collect::<Vec<_>>();
601 if self_spans.len() > 1 {
602 let mut e = self.r.into_struct_error(
604 ResolutionError::SelfImportCanOnlyAppearOnceInTheList,
607 for other_span in self_spans.iter().skip(1) {
608 e.span_label(*other_span, "another `self` import appears here");
614 for &(ref tree, id) in items {
615 self.build_reduced_graph_for_use_tree(
616 // This particular use tree
617 tree, id, &prefix, true, // The whole `use` item
618 item, vis, root_span,
622 // Empty groups `a::b::{}` are turned into synthetic `self` imports
623 // `a::b::c::{self as _}`, so that their prefixes are correctly
624 // resolved and checked for privacy/stability/etc.
625 if items.is_empty() && !empty_for_self(&prefix) {
626 let new_span = prefix[prefix.len() - 1].ident.span;
627 let tree = ast::UseTree {
628 prefix: ast::Path::from_ident(Ident::new(kw::SelfLower, new_span)),
629 kind: ast::UseTreeKind::Simple(
630 Some(Ident::new(kw::Underscore, new_span)),
636 self.build_reduced_graph_for_use_tree(
637 // This particular use tree
642 // The whole `use` item
644 ty::Visibility::Invisible,
652 /// Constructs the reduced graph for one item.
653 fn build_reduced_graph_for_item(&mut self, item: &'b Item) {
654 if matches!(item.kind, ItemKind::Mod(..)) && item.ident.name == kw::Empty {
655 // Fake crate root item from expand.
659 let parent_scope = &self.parent_scope;
660 let parent = parent_scope.module;
661 let expansion = parent_scope.expansion;
662 let ident = item.ident;
664 let vis = self.resolve_visibility(&item.vis);
665 let local_def_id = self.r.local_def_id(item.id);
666 let def_id = local_def_id.to_def_id();
668 self.r.visibilities.insert(local_def_id, vis);
671 ItemKind::Use(ref use_tree) => {
672 self.build_reduced_graph_for_use_tree(
673 // This particular use tree
678 // The whole `use` item
685 ItemKind::ExternCrate(orig_name) => {
686 let module = if orig_name.is_none() && ident.name == kw::SelfLower {
689 .struct_span_err(item.span, "`extern crate self;` requires renaming")
693 "extern crate self as name;".into(),
694 Applicability::HasPlaceholders,
698 } else if orig_name == Some(kw::SelfLower) {
701 let crate_id = self.r.crate_loader.process_extern_crate(
706 self.r.extern_crate_map.insert(local_def_id, crate_id);
707 self.r.expect_module(crate_id.as_def_id())
710 let used = self.process_macro_use_imports(item, module);
712 (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.r.arenas);
713 let import = self.r.arenas.alloc_import(Import {
714 kind: ImportKind::ExternCrate { source: orig_name, target: ident },
717 parent_scope: self.parent_scope,
718 imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
719 has_attributes: !item.attrs.is_empty(),
720 use_span_with_attributes: item.span_with_attributes(),
722 root_span: item.span,
724 module_path: Vec::new(),
726 used: Cell::new(used),
728 self.r.potentially_unused_imports.push(import);
729 let imported_binding = self.r.import(binding, import);
730 if ptr::eq(parent, self.r.graph_root) {
731 if let Some(entry) = self.r.extern_prelude.get(&ident.normalize_to_macros_2_0())
733 if expansion != LocalExpnId::ROOT
734 && orig_name.is_some()
735 && entry.extern_crate_item.is_none()
737 let msg = "macro-expanded `extern crate` items cannot \
738 shadow names passed with `--extern`";
739 self.r.session.span_err(item.span, msg);
743 self.r.extern_prelude.entry(ident.normalize_to_macros_2_0()).or_insert(
745 extern_crate_item: None,
746 introduced_by_item: true,
749 entry.extern_crate_item = Some(imported_binding);
750 if orig_name.is_some() {
751 entry.introduced_by_item = true;
754 self.r.define(parent, ident, TypeNS, imported_binding);
757 ItemKind::Mod(..) => {
758 let module = self.r.new_module(
760 ModuleKind::Def(DefKind::Mod, def_id, ident.name),
761 expansion.to_expn_id(),
763 parent.no_implicit_prelude
764 || self.r.session.contains_name(&item.attrs, sym::no_implicit_prelude),
766 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
768 // Descend into the module.
769 self.parent_scope.module = module;
772 // These items live in the value namespace.
773 ItemKind::Static(..) => {
774 let res = Res::Def(DefKind::Static, def_id);
775 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
777 ItemKind::Const(..) => {
778 let res = Res::Def(DefKind::Const, def_id);
779 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
781 ItemKind::Fn(..) => {
782 let res = Res::Def(DefKind::Fn, def_id);
783 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
785 // Functions introducing procedural macros reserve a slot
786 // in the macro namespace as well (see #52225).
787 self.define_macro(item);
790 // These items live in the type namespace.
791 ItemKind::TyAlias(..) => {
792 let res = Res::Def(DefKind::TyAlias, def_id);
793 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
796 ItemKind::Enum(_, _) => {
797 let module = self.r.new_module(
799 ModuleKind::Def(DefKind::Enum, def_id, ident.name),
800 expansion.to_expn_id(),
802 parent.no_implicit_prelude,
804 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
805 self.parent_scope.module = module;
808 ItemKind::TraitAlias(..) => {
809 let res = Res::Def(DefKind::TraitAlias, def_id);
810 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
813 // These items live in both the type and value namespaces.
814 ItemKind::Struct(ref vdata, _) => {
815 // Define a name in the type namespace.
816 let res = Res::Def(DefKind::Struct, def_id);
817 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
819 // Record field names for error reporting.
820 self.insert_field_names_local(def_id, vdata);
822 // If this is a tuple or unit struct, define a name
823 // in the value namespace as well.
824 if let Some(ctor_node_id) = vdata.ctor_id() {
825 // If the structure is marked as non_exhaustive then lower the visibility
826 // to within the crate.
827 let mut ctor_vis = if vis == ty::Visibility::Public
828 && self.r.session.contains_name(&item.attrs, sym::non_exhaustive)
830 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
835 let mut ret_fields = Vec::with_capacity(vdata.fields().len());
837 for field in vdata.fields() {
838 // NOTE: The field may be an expansion placeholder, but expansion sets
839 // correct visibilities for unnamed field placeholders specifically, so the
840 // constructor visibility should still be determined correctly.
842 .resolve_visibility_speculative(&field.vis, true)
843 .unwrap_or(ty::Visibility::Public);
844 if ctor_vis.is_at_least(field_vis, &*self.r) {
845 ctor_vis = field_vis;
847 ret_fields.push(field_vis);
849 let ctor_def_id = self.r.local_def_id(ctor_node_id);
850 let ctor_res = Res::Def(
851 DefKind::Ctor(CtorOf::Struct, CtorKind::from_ast(vdata)),
852 ctor_def_id.to_def_id(),
854 self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion));
855 self.r.visibilities.insert(ctor_def_id, ctor_vis);
857 self.r.struct_constructors.insert(def_id, (ctor_res, ctor_vis, ret_fields));
861 ItemKind::Union(ref vdata, _) => {
862 let res = Res::Def(DefKind::Union, def_id);
863 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
865 // Record field names for error reporting.
866 self.insert_field_names_local(def_id, vdata);
869 ItemKind::Trait(..) => {
870 // Add all the items within to a new module.
871 let module = self.r.new_module(
873 ModuleKind::Def(DefKind::Trait, def_id, ident.name),
874 expansion.to_expn_id(),
876 parent.no_implicit_prelude,
878 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
879 self.parent_scope.module = module;
882 // These items do not add names to modules.
883 ItemKind::Impl(box Impl { of_trait: Some(..), .. }) => {
884 self.r.trait_impl_items.insert(local_def_id);
886 ItemKind::Impl { .. } | ItemKind::ForeignMod(..) | ItemKind::GlobalAsm(..) => {}
888 ItemKind::MacroDef(..) | ItemKind::MacCall(_) => unreachable!(),
892 /// Constructs the reduced graph for one foreign item.
893 fn build_reduced_graph_for_foreign_item(&mut self, item: &ForeignItem) {
894 let local_def_id = self.r.local_def_id(item.id);
895 let def_id = local_def_id.to_def_id();
896 let (def_kind, ns) = match item.kind {
897 ForeignItemKind::Fn(..) => (DefKind::Fn, ValueNS),
898 ForeignItemKind::Static(..) => (DefKind::Static, ValueNS),
899 ForeignItemKind::TyAlias(..) => (DefKind::ForeignTy, TypeNS),
900 ForeignItemKind::MacCall(_) => unreachable!(),
902 let parent = self.parent_scope.module;
903 let expansion = self.parent_scope.expansion;
904 let vis = self.resolve_visibility(&item.vis);
905 let res = Res::Def(def_kind, def_id);
906 self.r.define(parent, item.ident, ns, (res, vis, item.span, expansion));
907 self.r.visibilities.insert(local_def_id, vis);
910 fn build_reduced_graph_for_block(&mut self, block: &Block) {
911 let parent = self.parent_scope.module;
912 let expansion = self.parent_scope.expansion;
913 if self.block_needs_anonymous_module(block) {
914 let module = self.r.new_module(
916 ModuleKind::Block(block.id),
917 expansion.to_expn_id(),
919 parent.no_implicit_prelude,
921 self.r.block_map.insert(block.id, module);
922 self.parent_scope.module = module; // Descend into the block.
926 /// Builds the reduced graph for a single item in an external crate.
927 fn build_reduced_graph_for_external_crate_res(&mut self, child: Export) {
928 let parent = self.parent_scope.module;
929 let Export { ident, res, vis, span } = child;
930 let res = res.expect_non_local();
931 let expansion = self.parent_scope.expansion;
932 // Record primary definitions.
934 Res::Def(DefKind::Mod | DefKind::Enum | DefKind::Trait, def_id) => {
935 let module = self.r.expect_module(def_id);
936 self.r.define(parent, ident, TypeNS, (module, vis, span, expansion));
945 | DefKind::TraitAlias
950 | Res::ToolMod => self.r.define(parent, ident, TypeNS, (res, vis, span, expansion)),
956 | DefKind::AssocConst
959 ) => self.r.define(parent, ident, ValueNS, (res, vis, span, expansion)),
960 Res::Def(DefKind::Macro(..), _) | Res::NonMacroAttr(..) => {
961 self.r.define(parent, ident, MacroNS, (res, vis, span, expansion))
965 | DefKind::ConstParam
966 | DefKind::ExternCrate
968 | DefKind::ForeignMod
970 | DefKind::InlineConst
972 | DefKind::LifetimeParam
976 | DefKind::Generator,
982 | Res::Err => bug!("unexpected resolution: {:?}", res),
984 // Record some extra data for better diagnostics.
985 let cstore = self.r.cstore();
987 Res::Def(DefKind::Struct, def_id) => {
988 let field_names = cstore.struct_field_names_untracked(def_id, self.r.session);
989 let ctor = cstore.ctor_def_id_and_kind_untracked(def_id);
990 if let Some((ctor_def_id, ctor_kind)) = ctor {
991 let ctor_res = Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id);
992 let ctor_vis = cstore.visibility_untracked(ctor_def_id);
993 let field_visibilities = cstore.struct_field_visibilities_untracked(def_id);
996 .insert(def_id, (ctor_res, ctor_vis, field_visibilities));
998 self.insert_field_names(def_id, field_names);
1000 Res::Def(DefKind::Union, def_id) => {
1001 let field_names = cstore.struct_field_names_untracked(def_id, self.r.session);
1002 self.insert_field_names(def_id, field_names);
1004 Res::Def(DefKind::AssocFn, def_id) => {
1006 .associated_item_cloned_untracked(def_id, self.r.session)
1007 .fn_has_self_parameter
1009 self.r.has_self.insert(def_id);
1016 fn add_macro_use_binding(
1019 binding: &'a NameBinding<'a>,
1021 allow_shadowing: bool,
1023 if self.r.macro_use_prelude.insert(name, binding).is_some() && !allow_shadowing {
1024 let msg = format!("`{}` is already in scope", name);
1026 "macro-expanded `#[macro_use]`s may not shadow existing macros (see RFC 1560)";
1027 self.r.session.struct_span_err(span, &msg).note(note).emit();
1031 /// Returns `true` if we should consider the underlying `extern crate` to be used.
1032 fn process_macro_use_imports(&mut self, item: &Item, module: Module<'a>) -> bool {
1033 let mut import_all = None;
1034 let mut single_imports = Vec::new();
1035 for attr in &item.attrs {
1036 if attr.has_name(sym::macro_use) {
1037 if self.parent_scope.module.parent.is_some() {
1042 "an `extern crate` loading macros must be at the crate root"
1046 if let ItemKind::ExternCrate(Some(orig_name)) = item.kind {
1047 if orig_name == kw::SelfLower {
1052 "`#[macro_use]` is not supported on `extern crate self`",
1058 |span| struct_span_err!(self.r.session, span, E0466, "bad macro import").emit();
1060 Some(meta) => match meta.kind {
1061 MetaItemKind::Word => {
1062 import_all = Some(meta.span);
1065 MetaItemKind::List(nested_metas) => {
1066 for nested_meta in nested_metas {
1067 match nested_meta.ident() {
1068 Some(ident) if nested_meta.is_word() => {
1069 single_imports.push(ident)
1071 _ => ill_formed(nested_meta.span()),
1075 MetaItemKind::NameValue(..) => ill_formed(meta.span),
1077 None => ill_formed(attr.span),
1082 let macro_use_import = |this: &Self, span| {
1083 this.r.arenas.alloc_import(Import {
1084 kind: ImportKind::MacroUse,
1087 parent_scope: this.parent_scope,
1088 imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
1089 use_span_with_attributes: item.span_with_attributes(),
1090 has_attributes: !item.attrs.is_empty(),
1091 use_span: item.span,
1094 module_path: Vec::new(),
1095 vis: Cell::new(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))),
1096 used: Cell::new(false),
1100 let allow_shadowing = self.parent_scope.expansion == LocalExpnId::ROOT;
1101 if let Some(span) = import_all {
1102 let import = macro_use_import(self, span);
1103 self.r.potentially_unused_imports.push(import);
1104 module.for_each_child(self, |this, ident, ns, binding| {
1106 let imported_binding = this.r.import(binding, import);
1107 this.add_macro_use_binding(ident.name, imported_binding, span, allow_shadowing);
1111 for ident in single_imports.iter().cloned() {
1112 let result = self.r.resolve_ident_in_module(
1113 ModuleOrUniformRoot::Module(module),
1120 if let Ok(binding) = result {
1121 let import = macro_use_import(self, ident.span);
1122 self.r.potentially_unused_imports.push(import);
1123 let imported_binding = self.r.import(binding, import);
1124 self.add_macro_use_binding(
1131 struct_span_err!(self.r.session, ident.span, E0469, "imported macro not found")
1136 import_all.is_some() || !single_imports.is_empty()
1139 /// Returns `true` if this attribute list contains `macro_use`.
1140 fn contains_macro_use(&mut self, attrs: &[ast::Attribute]) -> bool {
1142 if attr.has_name(sym::macro_escape) {
1143 let msg = "`#[macro_escape]` is a deprecated synonym for `#[macro_use]`";
1144 let mut err = self.r.session.struct_span_warn(attr.span, msg);
1145 if let ast::AttrStyle::Inner = attr.style {
1146 err.help("try an outer attribute: `#[macro_use]`").emit();
1150 } else if !attr.has_name(sym::macro_use) {
1154 if !attr.is_word() {
1155 self.r.session.span_err(attr.span, "arguments to `macro_use` are not allowed here");
1163 fn visit_invoc(&mut self, id: NodeId) -> LocalExpnId {
1164 let invoc_id = id.placeholder_to_expn_id();
1165 let old_parent_scope = self.r.invocation_parent_scopes.insert(invoc_id, self.parent_scope);
1166 assert!(old_parent_scope.is_none(), "invocation data is reset for an invocation");
1170 /// Visit invocation in context in which it can emit a named item (possibly `macro_rules`)
1171 /// directly into its parent scope's module.
1172 fn visit_invoc_in_module(&mut self, id: NodeId) -> MacroRulesScopeRef<'a> {
1173 let invoc_id = self.visit_invoc(id);
1174 self.parent_scope.module.unexpanded_invocations.borrow_mut().insert(invoc_id);
1175 self.r.arenas.alloc_macro_rules_scope(MacroRulesScope::Invocation(invoc_id))
1178 fn proc_macro_stub(&self, item: &ast::Item) -> Option<(MacroKind, Ident, Span)> {
1179 if self.r.session.contains_name(&item.attrs, sym::proc_macro) {
1180 return Some((MacroKind::Bang, item.ident, item.span));
1181 } else if self.r.session.contains_name(&item.attrs, sym::proc_macro_attribute) {
1182 return Some((MacroKind::Attr, item.ident, item.span));
1183 } else if let Some(attr) = self.r.session.find_by_name(&item.attrs, sym::proc_macro_derive)
1185 if let Some(nested_meta) = attr.meta_item_list().and_then(|list| list.get(0).cloned()) {
1186 if let Some(ident) = nested_meta.ident() {
1187 return Some((MacroKind::Derive, ident, ident.span));
1194 // Mark the given macro as unused unless its name starts with `_`.
1195 // Macro uses will remove items from this set, and the remaining
1196 // items will be reported as `unused_macros`.
1197 fn insert_unused_macro(
1204 if !ident.as_str().starts_with('_') {
1205 self.r.unused_macros.insert(def_id, (node_id, span));
1209 fn define_macro(&mut self, item: &ast::Item) -> MacroRulesScopeRef<'a> {
1210 let parent_scope = self.parent_scope;
1211 let expansion = parent_scope.expansion;
1212 let def_id = self.r.local_def_id(item.id);
1213 let (ext, ident, span, macro_rules) = match &item.kind {
1214 ItemKind::MacroDef(def) => {
1215 let ext = Lrc::new(self.r.compile_macro(item, self.r.session.edition()));
1216 (ext, item.ident, item.span, def.macro_rules)
1218 ItemKind::Fn(..) => match self.proc_macro_stub(item) {
1219 Some((macro_kind, ident, span)) => {
1220 self.r.proc_macro_stubs.insert(def_id);
1221 (self.r.dummy_ext(macro_kind), ident, span, false)
1223 None => return parent_scope.macro_rules,
1225 _ => unreachable!(),
1228 let res = Res::Def(DefKind::Macro(ext.macro_kind()), def_id.to_def_id());
1229 self.r.macro_map.insert(def_id.to_def_id(), ext);
1230 self.r.local_macro_def_scopes.insert(def_id, parent_scope.module);
1233 let ident = ident.normalize_to_macros_2_0();
1234 self.r.macro_names.insert(ident);
1235 let is_macro_export = self.r.session.contains_name(&item.attrs, sym::macro_export);
1236 let vis = if is_macro_export {
1237 ty::Visibility::Public
1239 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
1241 let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas);
1242 self.r.set_binding_parent_module(binding, parent_scope.module);
1243 self.r.all_macros.insert(ident.name, res);
1244 if is_macro_export {
1245 let module = self.r.graph_root;
1246 self.r.define(module, ident, MacroNS, (res, vis, span, expansion, IsMacroExport));
1248 self.r.check_reserved_macro_name(ident, res);
1249 self.insert_unused_macro(ident, def_id, item.id, span);
1251 self.r.visibilities.insert(def_id, vis);
1252 self.r.arenas.alloc_macro_rules_scope(MacroRulesScope::Binding(
1253 self.r.arenas.alloc_macro_rules_binding(MacroRulesBinding {
1254 parent_macro_rules_scope: parent_scope.macro_rules,
1260 let module = parent_scope.module;
1261 let vis = match item.kind {
1262 // Visibilities must not be resolved non-speculatively twice
1263 // and we already resolved this one as a `fn` item visibility.
1264 ItemKind::Fn(..) => self
1265 .resolve_visibility_speculative(&item.vis, true)
1266 .unwrap_or(ty::Visibility::Public),
1267 _ => self.resolve_visibility(&item.vis),
1269 if vis != ty::Visibility::Public {
1270 self.insert_unused_macro(ident, def_id, item.id, span);
1272 self.r.define(module, ident, MacroNS, (res, vis, span, expansion));
1273 self.r.visibilities.insert(def_id, vis);
1274 self.parent_scope.macro_rules
1279 macro_rules! method {
1280 ($visit:ident: $ty:ty, $invoc:path, $walk:ident) => {
1281 fn $visit(&mut self, node: &'b $ty) {
1282 if let $invoc(..) = node.kind {
1283 self.visit_invoc(node.id);
1285 visit::$walk(self, node);
1291 impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
1292 method!(visit_expr: ast::Expr, ast::ExprKind::MacCall, walk_expr);
1293 method!(visit_pat: ast::Pat, ast::PatKind::MacCall, walk_pat);
1294 method!(visit_ty: ast::Ty, ast::TyKind::MacCall, walk_ty);
1296 fn visit_item(&mut self, item: &'b Item) {
1297 let orig_module_scope = self.parent_scope.module;
1298 self.parent_scope.macro_rules = match item.kind {
1299 ItemKind::MacroDef(..) => {
1300 let macro_rules_scope = self.define_macro(item);
1301 visit::walk_item(self, item);
1304 ItemKind::MacCall(..) => {
1305 let macro_rules_scope = self.visit_invoc_in_module(item.id);
1306 visit::walk_item(self, item);
1310 let orig_macro_rules_scope = self.parent_scope.macro_rules;
1311 self.build_reduced_graph_for_item(item);
1312 visit::walk_item(self, item);
1314 ItemKind::Mod(..) if self.contains_macro_use(&item.attrs) => {
1315 self.parent_scope.macro_rules
1317 _ => orig_macro_rules_scope,
1321 self.parent_scope.module = orig_module_scope;
1324 fn visit_stmt(&mut self, stmt: &'b ast::Stmt) {
1325 if let ast::StmtKind::MacCall(..) = stmt.kind {
1326 self.parent_scope.macro_rules = self.visit_invoc_in_module(stmt.id);
1328 visit::walk_stmt(self, stmt);
1332 fn visit_foreign_item(&mut self, foreign_item: &'b ForeignItem) {
1333 if let ForeignItemKind::MacCall(_) = foreign_item.kind {
1334 self.visit_invoc_in_module(foreign_item.id);
1338 self.build_reduced_graph_for_foreign_item(foreign_item);
1339 visit::walk_foreign_item(self, foreign_item);
1342 fn visit_block(&mut self, block: &'b Block) {
1343 let orig_current_module = self.parent_scope.module;
1344 let orig_current_macro_rules_scope = self.parent_scope.macro_rules;
1345 self.build_reduced_graph_for_block(block);
1346 visit::walk_block(self, block);
1347 self.parent_scope.module = orig_current_module;
1348 self.parent_scope.macro_rules = orig_current_macro_rules_scope;
1351 fn visit_assoc_item(&mut self, item: &'b AssocItem, ctxt: AssocCtxt) {
1352 if let AssocItemKind::MacCall(_) = item.kind {
1354 AssocCtxt::Trait => {
1355 self.visit_invoc_in_module(item.id);
1357 AssocCtxt::Impl => {
1358 self.visit_invoc(item.id);
1364 let vis = self.resolve_visibility(&item.vis);
1365 let local_def_id = self.r.local_def_id(item.id);
1366 let def_id = local_def_id.to_def_id();
1368 if !(ctxt == AssocCtxt::Impl
1369 && matches!(item.vis.kind, ast::VisibilityKind::Inherited)
1373 .contains(&ty::DefIdTree::parent(&*self.r, def_id).unwrap().expect_local()))
1375 // Trait impl item visibility is inherited from its trait when not specified
1376 // explicitly. In that case we cannot determine it here in early resolve,
1377 // so we leave a hole in the visibility table to be filled later.
1378 self.r.visibilities.insert(local_def_id, vis);
1381 if ctxt == AssocCtxt::Trait {
1382 let (def_kind, ns) = match item.kind {
1383 AssocItemKind::Const(..) => (DefKind::AssocConst, ValueNS),
1384 AssocItemKind::Fn(box Fn { ref sig, .. }) => {
1385 if sig.decl.has_self() {
1386 self.r.has_self.insert(def_id);
1388 (DefKind::AssocFn, ValueNS)
1390 AssocItemKind::TyAlias(..) => (DefKind::AssocTy, TypeNS),
1391 AssocItemKind::MacCall(_) => bug!(), // handled above
1394 let parent = self.parent_scope.module;
1395 let expansion = self.parent_scope.expansion;
1396 let res = Res::Def(def_kind, def_id);
1397 self.r.define(parent, item.ident, ns, (res, vis, item.span, expansion));
1400 visit::walk_assoc_item(self, item, ctxt);
1403 fn visit_attribute(&mut self, attr: &'b ast::Attribute) {
1404 if !attr.is_doc_comment() && attr::is_builtin_attr(attr) {
1407 .push((attr.get_normal_item().path.segments[0].ident, self.parent_scope));
1409 visit::walk_attribute(self, attr);
1412 fn visit_arm(&mut self, arm: &'b ast::Arm) {
1413 if arm.is_placeholder {
1414 self.visit_invoc(arm.id);
1416 visit::walk_arm(self, arm);
1420 fn visit_expr_field(&mut self, f: &'b ast::ExprField) {
1421 if f.is_placeholder {
1422 self.visit_invoc(f.id);
1424 visit::walk_expr_field(self, f);
1428 fn visit_pat_field(&mut self, fp: &'b ast::PatField) {
1429 if fp.is_placeholder {
1430 self.visit_invoc(fp.id);
1432 visit::walk_pat_field(self, fp);
1436 fn visit_generic_param(&mut self, param: &'b ast::GenericParam) {
1437 if param.is_placeholder {
1438 self.visit_invoc(param.id);
1440 visit::walk_generic_param(self, param);
1444 fn visit_param(&mut self, p: &'b ast::Param) {
1445 if p.is_placeholder {
1446 self.visit_invoc(p.id);
1448 visit::walk_param(self, p);
1452 fn visit_field_def(&mut self, sf: &'b ast::FieldDef) {
1453 if sf.is_placeholder {
1454 self.visit_invoc(sf.id);
1456 let vis = self.resolve_visibility(&sf.vis);
1457 self.r.visibilities.insert(self.r.local_def_id(sf.id), vis);
1458 visit::walk_field_def(self, sf);
1462 // Constructs the reduced graph for one variant. Variants exist in the
1463 // type and value namespaces.
1464 fn visit_variant(&mut self, variant: &'b ast::Variant) {
1465 if variant.is_placeholder {
1466 self.visit_invoc_in_module(variant.id);
1470 let parent = self.parent_scope.module;
1471 let expn_id = self.parent_scope.expansion;
1472 let ident = variant.ident;
1474 // Define a name in the type namespace.
1475 let def_id = self.r.local_def_id(variant.id);
1476 let res = Res::Def(DefKind::Variant, def_id.to_def_id());
1477 let vis = self.resolve_visibility(&variant.vis);
1478 self.r.define(parent, ident, TypeNS, (res, vis, variant.span, expn_id));
1479 self.r.visibilities.insert(def_id, vis);
1481 // If the variant is marked as non_exhaustive then lower the visibility to within the crate.
1482 let ctor_vis = if vis == ty::Visibility::Public
1483 && self.r.session.contains_name(&variant.attrs, sym::non_exhaustive)
1485 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
1490 // Define a constructor name in the value namespace.
1491 // Braced variants, unlike structs, generate unusable names in
1492 // value namespace, they are reserved for possible future use.
1493 // It's ok to use the variant's id as a ctor id since an
1494 // error will be reported on any use of such resolution anyway.
1495 let ctor_node_id = variant.data.ctor_id().unwrap_or(variant.id);
1496 let ctor_def_id = self.r.local_def_id(ctor_node_id);
1497 let ctor_kind = CtorKind::from_ast(&variant.data);
1498 let ctor_res = Res::Def(DefKind::Ctor(CtorOf::Variant, ctor_kind), ctor_def_id.to_def_id());
1499 self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, variant.span, expn_id));
1500 if ctor_def_id != def_id {
1501 self.r.visibilities.insert(ctor_def_id, ctor_vis);
1503 // Record field names for error reporting.
1504 self.insert_field_names_local(ctor_def_id.to_def_id(), &variant.data);
1506 visit::walk_variant(self, variant);