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};
11 use crate::Namespace::{self, MacroNS, TypeNS, ValueNS};
12 use crate::{CrateLint, Determinacy, PathResult, ResolutionError, VisResolutionError};
14 ExternPreludeEntry, ModuleOrUniformRoot, ParentScope, PerNS, Resolver, ResolverArenas,
16 use crate::{Module, ModuleData, ModuleKind, NameBinding, NameBindingKind, Segment, ToNameBinding};
18 use rustc_ast::ast::{self, Block, ForeignItem, ForeignItemKind, Item, ItemKind, NodeId};
19 use rustc_ast::ast::{AssocItem, AssocItemKind, MetaItemKind, StmtKind};
20 use rustc_ast::token::{self, Token};
21 use rustc_ast::visit::{self, AssocCtxt, Visitor};
22 use rustc_ast_lowering::ResolverAstLowering;
23 use rustc_attr as attr;
24 use rustc_data_structures::sync::Lrc;
25 use rustc_errors::{struct_span_err, Applicability};
26 use rustc_expand::base::SyntaxExtension;
27 use rustc_expand::expand::AstFragment;
28 use rustc_hir::def::{self, *};
29 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX};
30 use rustc_metadata::creader::LoadedMacro;
31 use rustc_middle::bug;
32 use rustc_middle::hir::exports::Export;
33 use rustc_middle::middle::cstore::CrateStore;
35 use rustc_span::hygiene::{ExpnId, MacroKind};
36 use rustc_span::source_map::{respan, Spanned};
37 use rustc_span::symbol::{kw, sym, Ident, Symbol};
44 type Res = def::Res<NodeId>;
46 impl<'a> ToNameBinding<'a> for (Module<'a>, ty::Visibility, Span, ExpnId) {
47 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
48 arenas.alloc_name_binding(NameBinding {
49 kind: NameBindingKind::Module(self.0),
58 impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, ExpnId) {
59 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
60 arenas.alloc_name_binding(NameBinding {
61 kind: NameBindingKind::Res(self.0, false),
72 impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, ExpnId, IsMacroExport) {
73 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
74 arenas.alloc_name_binding(NameBinding {
75 kind: NameBindingKind::Res(self.0, true),
84 impl<'a> Resolver<'a> {
85 /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
86 /// otherwise, reports an error.
87 crate fn define<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
91 let binding = def.to_name_binding(self.arenas);
92 let key = self.new_key(ident, ns);
93 if let Err(old_binding) = self.try_define(parent, key, binding) {
94 self.report_conflict(parent, ident, ns, old_binding, &binding);
98 crate fn get_module(&mut self, def_id: DefId) -> Module<'a> {
99 // If this is a local module, it will be in `module_map`, no need to recalculate it.
100 if let Some(def_id) = def_id.as_local() {
101 return self.module_map[&def_id];
104 // Cache module resolution
105 if let Some(&module) = self.extern_module_map.get(&def_id) {
109 let (name, parent) = if def_id.index == CRATE_DEF_INDEX {
110 // This is the crate root
111 (self.cstore().crate_name_untracked(def_id.krate), None)
113 let def_key = self.cstore().def_key(def_id);
118 .expect("given a DefId that wasn't a module");
119 // This unwrap is safe since we know this isn't the root
120 let parent = Some(self.get_module(DefId {
121 index: def_key.parent.expect("failed to get parent for module"),
127 // Allocate and return a new module with the information we found
128 let kind = ModuleKind::Def(DefKind::Mod, def_id, name);
129 let module = self.arenas.alloc_module(ModuleData::new(
133 self.cstore().module_expansion_untracked(def_id, &self.session),
134 self.cstore().get_span_untracked(def_id, &self.session),
136 self.extern_module_map.insert(def_id, module);
140 crate fn macro_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
141 let def_id = match expn_id.expn_data().macro_def_id {
142 Some(def_id) => def_id,
143 None => return self.ast_transform_scopes.get(&expn_id).unwrap_or(&self.graph_root),
145 if let Some(id) = def_id.as_local() {
146 self.local_macro_def_scopes[&id]
148 let module_def_id = ty::DefIdTree::parent(&*self, def_id).unwrap();
149 self.get_module(module_def_id)
153 crate fn get_macro(&mut self, res: Res) -> Option<Lrc<SyntaxExtension>> {
155 Res::Def(DefKind::Macro(..), def_id) => self.get_macro_by_def_id(def_id),
156 Res::NonMacroAttr(attr_kind) => Some(self.non_macro_attr(attr_kind.is_used())),
161 crate fn get_macro_by_def_id(&mut self, def_id: DefId) -> Option<Lrc<SyntaxExtension>> {
162 if let Some(ext) = self.macro_map.get(&def_id) {
163 return Some(ext.clone());
166 let ext = Lrc::new(match self.cstore().load_macro_untracked(def_id, &self.session) {
167 LoadedMacro::MacroDef(item, edition) => self.compile_macro(&item, edition),
168 LoadedMacro::ProcMacro(ext) => ext,
171 self.macro_map.insert(def_id, ext.clone());
175 crate fn build_reduced_graph(
177 fragment: &AstFragment,
178 parent_scope: ParentScope<'a>,
179 ) -> MacroRulesScope<'a> {
180 collect_definitions(self, fragment, parent_scope.expansion);
181 let mut visitor = BuildReducedGraphVisitor { r: self, parent_scope };
182 fragment.visit_with(&mut visitor);
183 visitor.parent_scope.macro_rules
186 crate fn build_reduced_graph_external(&mut self, module: Module<'a>) {
187 let def_id = module.def_id().expect("unpopulated module without a def-id");
188 for child in self.cstore().item_children_untracked(def_id, self.session) {
189 let child = child.map_id(|_| panic!("unexpected id"));
190 BuildReducedGraphVisitor { r: self, parent_scope: ParentScope::module(module) }
191 .build_reduced_graph_for_external_crate_res(child);
196 struct BuildReducedGraphVisitor<'a, 'b> {
197 r: &'b mut Resolver<'a>,
198 parent_scope: ParentScope<'a>,
201 impl<'a> AsMut<Resolver<'a>> for BuildReducedGraphVisitor<'a, '_> {
202 fn as_mut(&mut self) -> &mut Resolver<'a> {
207 impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
208 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
209 self.resolve_visibility_speculative(vis, false).unwrap_or_else(|err| {
210 self.r.report_vis_error(err);
211 ty::Visibility::Public
215 fn resolve_visibility_speculative<'ast>(
217 vis: &'ast ast::Visibility,
219 ) -> Result<ty::Visibility, VisResolutionError<'ast>> {
220 let parent_scope = &self.parent_scope;
222 ast::VisibilityKind::Public => Ok(ty::Visibility::Public),
223 ast::VisibilityKind::Crate(..) => {
224 Ok(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)))
226 ast::VisibilityKind::Inherited => {
227 Ok(ty::Visibility::Restricted(parent_scope.module.normal_ancestor_id))
229 ast::VisibilityKind::Restricted { ref path, id, .. } => {
230 // For visibilities we are not ready to provide correct implementation of "uniform
231 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
232 // On 2015 edition visibilities are resolved as crate-relative by default,
233 // so we are prepending a root segment if necessary.
234 let ident = path.segments.get(0).expect("empty path in visibility").ident;
235 let crate_root = if ident.is_path_segment_keyword() {
237 } else if ident.span.rust_2015() {
238 Some(Segment::from_ident(Ident::new(
240 path.span.shrink_to_lo().with_ctxt(ident.span.ctxt()),
243 return Err(VisResolutionError::Relative2018(ident.span, path));
246 let segments = crate_root
248 .chain(path.segments.iter().map(|seg| seg.into()))
249 .collect::<Vec<_>>();
250 let expected_found_error = |res| {
251 Err(VisResolutionError::ExpectedFound(
253 Segment::names_to_string(&segments),
257 match self.r.resolve_path(
263 CrateLint::SimplePath(id),
265 PathResult::Module(ModuleOrUniformRoot::Module(module)) => {
266 let res = module.res().expect("visibility resolved to unnamed block");
268 self.r.record_partial_res(id, PartialRes::new(res));
270 if module.is_normal() {
272 Ok(ty::Visibility::Public)
274 let vis = ty::Visibility::Restricted(res.def_id());
275 if self.r.is_accessible_from(vis, parent_scope.module) {
278 Err(VisResolutionError::AncestorOnly(path.span))
282 expected_found_error(res)
285 PathResult::Module(..) => Err(VisResolutionError::ModuleOnly(path.span)),
286 PathResult::NonModule(partial_res) => {
287 expected_found_error(partial_res.base_res())
289 PathResult::Failed { span, label, suggestion, .. } => {
290 Err(VisResolutionError::FailedToResolve(span, label, suggestion))
292 PathResult::Indeterminate => Err(VisResolutionError::Indeterminate(path.span)),
298 fn insert_field_names_local(&mut self, def_id: DefId, vdata: &ast::VariantData) {
299 let field_names = vdata
302 .map(|field| respan(field.span, field.ident.map_or(kw::Invalid, |ident| ident.name)))
304 self.insert_field_names(def_id, field_names);
307 fn insert_field_names(&mut self, def_id: DefId, field_names: Vec<Spanned<Symbol>>) {
308 self.r.field_names.insert(def_id, field_names);
311 fn block_needs_anonymous_module(&mut self, block: &Block) -> bool {
312 // If any statements are items, we need to create an anonymous module
313 block.stmts.iter().any(|statement| match statement.kind {
314 StmtKind::Item(_) | StmtKind::MacCall(_) => true,
319 // Add an import to the current module.
322 module_path: Vec<Segment>,
323 kind: ImportKind<'a>,
331 let current_module = self.parent_scope.module;
332 let import = self.r.arenas.alloc_import(Import {
334 parent_scope: self.parent_scope,
336 imported_module: Cell::new(None),
340 use_span_with_attributes: item.span_with_attributes(),
341 has_attributes: !item.attrs.is_empty(),
345 used: Cell::new(false),
348 debug!("add_import({:?})", import);
350 self.r.indeterminate_imports.push(import);
352 // Don't add unresolved underscore imports to modules
353 ImportKind::Single { target: Ident { name: kw::Underscore, .. }, .. } => {}
354 ImportKind::Single { target, type_ns_only, .. } => {
355 self.r.per_ns(|this, ns| {
356 if !type_ns_only || ns == TypeNS {
357 let key = this.new_key(target, ns);
358 let mut resolution = this.resolution(current_module, key).borrow_mut();
359 resolution.add_single_import(import);
363 // We don't add prelude imports to the globs since they only affect lexical scopes,
364 // which are not relevant to import resolution.
365 ImportKind::Glob { is_prelude: true, .. } => {}
366 ImportKind::Glob { .. } => current_module.globs.borrow_mut().push(import),
371 fn build_reduced_graph_for_use_tree(
373 // This particular use tree
374 use_tree: &ast::UseTree,
376 parent_prefix: &[Segment],
378 // The whole `use` item
384 "build_reduced_graph_for_use_tree(parent_prefix={:?}, use_tree={:?}, nested={})",
385 parent_prefix, use_tree, nested
388 let mut prefix_iter = parent_prefix
391 .chain(use_tree.prefix.segments.iter().map(|seg| seg.into()))
394 // On 2015 edition imports are resolved as crate-relative by default,
395 // so prefixes are prepended with crate root segment if necessary.
396 // The root is prepended lazily, when the first non-empty prefix or terminating glob
397 // appears, so imports in braced groups can have roots prepended independently.
398 let is_glob = if let ast::UseTreeKind::Glob = use_tree.kind { true } else { false };
399 let crate_root = match prefix_iter.peek() {
400 Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.rust_2015() => {
401 Some(seg.ident.span.ctxt())
403 None if is_glob && use_tree.span.rust_2015() => Some(use_tree.span.ctxt()),
407 Segment::from_ident(Ident::new(
409 use_tree.prefix.span.shrink_to_lo().with_ctxt(ctxt),
413 let prefix = crate_root.into_iter().chain(prefix_iter).collect::<Vec<_>>();
414 debug!("build_reduced_graph_for_use_tree: prefix={:?}", prefix);
416 let empty_for_self = |prefix: &[Segment]| {
417 prefix.is_empty() || prefix.len() == 1 && prefix[0].ident.name == kw::PathRoot
419 match use_tree.kind {
420 ast::UseTreeKind::Simple(rename, ..) => {
421 let mut ident = use_tree.ident();
422 let mut module_path = prefix;
423 let mut source = module_path.pop().unwrap();
424 let mut type_ns_only = false;
427 // Correctly handle `self`
428 if source.ident.name == kw::SelfLower {
431 if empty_for_self(&module_path) {
434 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix,
439 // Replace `use foo::{ self };` with `use foo;`
440 source = module_path.pop().unwrap();
441 if rename.is_none() {
442 ident = source.ident;
447 if source.ident.name == kw::SelfLower {
448 let parent = module_path.last();
450 let span = match parent {
451 // only `::self` from `use foo::self as bar`
452 Some(seg) => seg.ident.span.shrink_to_hi().to(source.ident.span),
453 None => source.ident.span,
455 let span_with_rename = match rename {
456 // only `self as bar` from `use foo::self as bar`
457 Some(rename) => source.ident.span.to(rename.span),
458 None => source.ident.span,
462 ResolutionError::SelfImportsOnlyAllowedWithin {
463 root: parent.is_none(),
468 // Error recovery: replace `use foo::self;` with `use foo;`
469 if let Some(parent) = module_path.pop() {
471 if rename.is_none() {
472 ident = source.ident;
477 // Disallow `use $crate;`
478 if source.ident.name == kw::DollarCrate && module_path.is_empty() {
479 let crate_root = self.r.resolve_crate_root(source.ident);
480 let crate_name = match crate_root.kind {
481 ModuleKind::Def(.., name) => name,
482 ModuleKind::Block(..) => unreachable!(),
484 // HACK(eddyb) unclear how good this is, but keeping `$crate`
485 // in `source` breaks `src/test/compile-fail/import-crate-var.rs`,
486 // while the current crate doesn't have a valid `crate_name`.
487 if crate_name != kw::Invalid {
488 // `crate_name` should not be interpreted as relative.
489 module_path.push(Segment {
490 ident: Ident { name: kw::PathRoot, span: source.ident.span },
491 id: Some(self.r.next_node_id()),
492 has_generic_args: false,
494 source.ident.name = crate_name;
496 if rename.is_none() {
497 ident.name = crate_name;
502 .struct_span_err(item.span, "`$crate` may not be imported")
507 if ident.name == kw::Crate {
508 self.r.session.span_err(
510 "crate root imports need to be explicitly named: \
511 `use crate as name;`",
515 let kind = ImportKind::Single {
516 source: source.ident,
518 source_bindings: PerNS {
519 type_ns: Cell::new(Err(Determinacy::Undetermined)),
520 value_ns: Cell::new(Err(Determinacy::Undetermined)),
521 macro_ns: Cell::new(Err(Determinacy::Undetermined)),
523 target_bindings: PerNS {
524 type_ns: Cell::new(None),
525 value_ns: Cell::new(None),
526 macro_ns: Cell::new(None),
542 ast::UseTreeKind::Glob => {
543 let kind = ImportKind::Glob {
544 is_prelude: attr::contains_name(&item.attrs, sym::prelude_import),
545 max_vis: Cell::new(ty::Visibility::Invisible),
547 self.add_import(prefix, kind, use_tree.span, id, item, root_span, item.id, vis);
549 ast::UseTreeKind::Nested(ref items) => {
550 // Ensure there is at most one `self` in the list
551 let self_spans = items
553 .filter_map(|&(ref use_tree, _)| {
554 if let ast::UseTreeKind::Simple(..) = use_tree.kind {
555 if use_tree.ident().name == kw::SelfLower {
556 return Some(use_tree.span);
562 .collect::<Vec<_>>();
563 if self_spans.len() > 1 {
564 let mut e = self.r.into_struct_error(
566 ResolutionError::SelfImportCanOnlyAppearOnceInTheList,
569 for other_span in self_spans.iter().skip(1) {
570 e.span_label(*other_span, "another `self` import appears here");
576 for &(ref tree, id) in items {
577 self.build_reduced_graph_for_use_tree(
578 // This particular use tree
579 tree, id, &prefix, true, // The whole `use` item
580 item, vis, root_span,
584 // Empty groups `a::b::{}` are turned into synthetic `self` imports
585 // `a::b::c::{self as _}`, so that their prefixes are correctly
586 // resolved and checked for privacy/stability/etc.
587 if items.is_empty() && !empty_for_self(&prefix) {
588 let new_span = prefix[prefix.len() - 1].ident.span;
589 let tree = ast::UseTree {
590 prefix: ast::Path::from_ident(Ident::new(kw::SelfLower, new_span)),
591 kind: ast::UseTreeKind::Simple(
592 Some(Ident::new(kw::Underscore, new_span)),
598 self.build_reduced_graph_for_use_tree(
599 // This particular use tree
604 // The whole `use` item
606 ty::Visibility::Invisible,
614 /// Constructs the reduced graph for one item.
615 fn build_reduced_graph_for_item(&mut self, item: &'b Item) {
616 let parent_scope = &self.parent_scope;
617 let parent = parent_scope.module;
618 let expansion = parent_scope.expansion;
619 let ident = item.ident;
621 let vis = self.resolve_visibility(&item.vis);
624 ItemKind::Use(ref use_tree) => {
625 self.build_reduced_graph_for_use_tree(
626 // This particular use tree
631 // The whole `use` item
638 ItemKind::ExternCrate(orig_name) => {
639 let module = if orig_name.is_none() && ident.name == kw::SelfLower {
642 .struct_span_err(item.span, "`extern crate self;` requires renaming")
646 "extern crate self as name;".into(),
647 Applicability::HasPlaceholders,
651 } else if orig_name == Some(kw::SelfLower) {
654 let def_id = self.r.local_def_id(item.id);
656 self.r.crate_loader.process_extern_crate(item, &self.r.definitions, def_id);
657 self.r.extern_crate_map.insert(def_id, crate_id);
658 self.r.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX })
661 let used = self.process_macro_use_imports(item, module);
663 (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.r.arenas);
664 let import = self.r.arenas.alloc_import(Import {
665 kind: ImportKind::ExternCrate { source: orig_name, target: ident },
668 parent_scope: self.parent_scope,
669 imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
670 has_attributes: !item.attrs.is_empty(),
671 use_span_with_attributes: item.span_with_attributes(),
673 root_span: item.span,
675 module_path: Vec::new(),
677 used: Cell::new(used),
679 self.r.potentially_unused_imports.push(import);
680 let imported_binding = self.r.import(binding, import);
681 if ptr::eq(parent, self.r.graph_root) {
682 if let Some(entry) = self.r.extern_prelude.get(&ident.normalize_to_macros_2_0())
684 if expansion != ExpnId::root()
685 && orig_name.is_some()
686 && entry.extern_crate_item.is_none()
688 let msg = "macro-expanded `extern crate` items cannot \
689 shadow names passed with `--extern`";
690 self.r.session.span_err(item.span, msg);
694 self.r.extern_prelude.entry(ident.normalize_to_macros_2_0()).or_insert(
696 extern_crate_item: None,
697 introduced_by_item: true,
700 entry.extern_crate_item = Some(imported_binding);
701 if orig_name.is_some() {
702 entry.introduced_by_item = true;
705 self.r.define(parent, ident, TypeNS, imported_binding);
708 ItemKind::Mod(..) if ident.name == kw::Invalid => {} // Crate root
710 ItemKind::Mod(..) => {
711 let def_id = self.r.local_def_id(item.id);
712 let module_kind = ModuleKind::Def(DefKind::Mod, def_id.to_def_id(), ident.name);
713 let module = self.r.arenas.alloc_module(ModuleData {
714 no_implicit_prelude: parent.no_implicit_prelude || {
715 attr::contains_name(&item.attrs, sym::no_implicit_prelude)
725 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
726 self.r.module_map.insert(def_id, module);
728 // Descend into the module.
729 self.parent_scope.module = module;
732 // These items live in the value namespace.
733 ItemKind::Static(..) => {
734 let res = Res::Def(DefKind::Static, self.r.local_def_id(item.id).to_def_id());
735 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
737 ItemKind::Const(..) => {
738 let res = Res::Def(DefKind::Const, self.r.local_def_id(item.id).to_def_id());
739 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
741 ItemKind::Fn(..) => {
742 let res = Res::Def(DefKind::Fn, self.r.local_def_id(item.id).to_def_id());
743 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
745 // Functions introducing procedural macros reserve a slot
746 // in the macro namespace as well (see #52225).
747 self.define_macro(item);
750 // These items live in the type namespace.
751 ItemKind::TyAlias(..) => {
752 let res = Res::Def(DefKind::TyAlias, self.r.local_def_id(item.id).to_def_id());
753 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
756 ItemKind::Enum(_, _) => {
757 let def_id = self.r.local_def_id(item.id).to_def_id();
758 self.r.variant_vis.insert(def_id, vis);
759 let module_kind = ModuleKind::Def(DefKind::Enum, def_id, ident.name);
760 let module = self.r.new_module(
763 parent.normal_ancestor_id,
767 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
768 self.parent_scope.module = module;
771 ItemKind::TraitAlias(..) => {
772 let res = Res::Def(DefKind::TraitAlias, self.r.local_def_id(item.id).to_def_id());
773 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
776 // These items live in both the type and value namespaces.
777 ItemKind::Struct(ref vdata, _) => {
778 // Define a name in the type namespace.
779 let def_id = self.r.local_def_id(item.id).to_def_id();
780 let res = Res::Def(DefKind::Struct, def_id);
781 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
783 // Record field names for error reporting.
784 self.insert_field_names_local(def_id, vdata);
786 // If this is a tuple or unit struct, define a name
787 // in the value namespace as well.
788 if let Some(ctor_node_id) = vdata.ctor_id() {
789 // If the structure is marked as non_exhaustive then lower the visibility
790 // to within the crate.
791 let mut ctor_vis = if vis == ty::Visibility::Public
792 && attr::contains_name(&item.attrs, sym::non_exhaustive)
794 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
799 for field in vdata.fields() {
800 // NOTE: The field may be an expansion placeholder, but expansion sets
801 // correct visibilities for unnamed field placeholders specifically, so the
802 // constructor visibility should still be determined correctly.
803 if let Ok(field_vis) = self.resolve_visibility_speculative(&field.vis, true)
805 if ctor_vis.is_at_least(field_vis, &*self.r) {
806 ctor_vis = field_vis;
810 let ctor_res = Res::Def(
811 DefKind::Ctor(CtorOf::Struct, CtorKind::from_ast(vdata)),
812 self.r.local_def_id(ctor_node_id).to_def_id(),
814 self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion));
815 self.r.struct_constructors.insert(def_id, (ctor_res, ctor_vis));
819 ItemKind::Union(ref vdata, _) => {
820 let def_id = self.r.local_def_id(item.id).to_def_id();
821 let res = Res::Def(DefKind::Union, def_id);
822 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
824 // Record field names for error reporting.
825 self.insert_field_names_local(def_id, vdata);
828 ItemKind::Trait(..) => {
829 let def_id = self.r.local_def_id(item.id).to_def_id();
831 // Add all the items within to a new module.
832 let module_kind = ModuleKind::Def(DefKind::Trait, def_id, ident.name);
833 let module = self.r.new_module(
836 parent.normal_ancestor_id,
840 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
841 self.parent_scope.module = module;
844 // These items do not add names to modules.
845 ItemKind::Impl { .. } | ItemKind::ForeignMod(..) | ItemKind::GlobalAsm(..) => {}
847 ItemKind::MacroDef(..) | ItemKind::MacCall(_) => unreachable!(),
851 /// Constructs the reduced graph for one foreign item.
852 fn build_reduced_graph_for_foreign_item(&mut self, item: &ForeignItem) {
853 let (res, ns) = match item.kind {
854 ForeignItemKind::Fn(..) => {
855 (Res::Def(DefKind::Fn, self.r.local_def_id(item.id).to_def_id()), ValueNS)
857 ForeignItemKind::Static(..) => {
858 (Res::Def(DefKind::Static, self.r.local_def_id(item.id).to_def_id()), ValueNS)
860 ForeignItemKind::TyAlias(..) => {
861 (Res::Def(DefKind::ForeignTy, self.r.local_def_id(item.id).to_def_id()), TypeNS)
863 ForeignItemKind::MacCall(_) => unreachable!(),
865 let parent = self.parent_scope.module;
866 let expansion = self.parent_scope.expansion;
867 let vis = self.resolve_visibility(&item.vis);
868 self.r.define(parent, item.ident, ns, (res, vis, item.span, expansion));
871 fn build_reduced_graph_for_block(&mut self, block: &Block) {
872 let parent = self.parent_scope.module;
873 let expansion = self.parent_scope.expansion;
874 if self.block_needs_anonymous_module(block) {
875 let module = self.r.new_module(
877 ModuleKind::Block(block.id),
878 parent.normal_ancestor_id,
882 self.r.block_map.insert(block.id, module);
883 self.parent_scope.module = module; // Descend into the block.
887 /// Builds the reduced graph for a single item in an external crate.
888 fn build_reduced_graph_for_external_crate_res(&mut self, child: Export<NodeId>) {
889 let parent = self.parent_scope.module;
890 let Export { ident, res, vis, span } = child;
891 let expansion = self.parent_scope.expansion;
892 // Record primary definitions.
894 Res::Def(kind @ (DefKind::Mod | DefKind::Enum | DefKind::Trait), def_id) => {
895 let module = self.r.new_module(
897 ModuleKind::Def(kind, def_id, ident.name),
902 self.r.define(parent, ident, TypeNS, (module, vis, span, expansion));
911 | DefKind::TraitAlias
916 | Res::ToolMod => self.r.define(parent, ident, TypeNS, (res, vis, span, expansion)),
922 | DefKind::AssocConst
925 ) => self.r.define(parent, ident, ValueNS, (res, vis, span, expansion)),
926 Res::Def(DefKind::Macro(..), _) | Res::NonMacroAttr(..) => {
927 self.r.define(parent, ident, MacroNS, (res, vis, span, expansion))
931 | DefKind::ConstParam
932 | DefKind::ExternCrate
934 | DefKind::ForeignMod
937 | DefKind::LifetimeParam
941 | DefKind::Generator,
947 | Res::Err => bug!("unexpected resolution: {:?}", res),
949 // Record some extra data for better diagnostics.
950 let cstore = self.r.cstore();
952 Res::Def(DefKind::Struct | DefKind::Union, def_id) => {
953 let field_names = cstore.struct_field_names_untracked(def_id, self.r.session);
954 self.insert_field_names(def_id, field_names);
956 Res::Def(DefKind::AssocFn, def_id) => {
958 .associated_item_cloned_untracked(def_id, self.r.session)
959 .fn_has_self_parameter
961 self.r.has_self.insert(def_id);
964 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), def_id) => {
965 let parent = cstore.def_key(def_id).parent;
966 if let Some(struct_def_id) = parent.map(|index| DefId { index, ..def_id }) {
967 self.r.struct_constructors.insert(struct_def_id, (res, vis));
974 fn add_macro_use_binding(
977 binding: &'a NameBinding<'a>,
979 allow_shadowing: bool,
981 if self.r.macro_use_prelude.insert(name, binding).is_some() && !allow_shadowing {
982 let msg = format!("`{}` is already in scope", name);
984 "macro-expanded `#[macro_use]`s may not shadow existing macros (see RFC 1560)";
985 self.r.session.struct_span_err(span, &msg).note(note).emit();
989 /// Returns `true` if we should consider the underlying `extern crate` to be used.
990 fn process_macro_use_imports(&mut self, item: &Item, module: Module<'a>) -> bool {
991 let mut import_all = None;
992 let mut single_imports = Vec::new();
993 for attr in &item.attrs {
994 if attr.check_name(sym::macro_use) {
995 if self.parent_scope.module.parent.is_some() {
1000 "an `extern crate` loading macros must be at the crate root"
1004 if let ItemKind::ExternCrate(Some(orig_name)) = item.kind {
1005 if orig_name == kw::SelfLower {
1010 "`#[macro_use]` is not supported on `extern crate self`",
1016 |span| struct_span_err!(self.r.session, span, E0466, "bad macro import").emit();
1018 Some(meta) => match meta.kind {
1019 MetaItemKind::Word => {
1020 import_all = Some(meta.span);
1023 MetaItemKind::List(nested_metas) => {
1024 for nested_meta in nested_metas {
1025 match nested_meta.ident() {
1026 Some(ident) if nested_meta.is_word() => {
1027 single_imports.push(ident)
1029 _ => ill_formed(nested_meta.span()),
1033 MetaItemKind::NameValue(..) => ill_formed(meta.span),
1035 None => ill_formed(attr.span),
1040 let macro_use_import = |this: &Self, span| {
1041 this.r.arenas.alloc_import(Import {
1042 kind: ImportKind::MacroUse,
1045 parent_scope: this.parent_scope,
1046 imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
1047 use_span_with_attributes: item.span_with_attributes(),
1048 has_attributes: !item.attrs.is_empty(),
1049 use_span: item.span,
1052 module_path: Vec::new(),
1053 vis: Cell::new(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))),
1054 used: Cell::new(false),
1058 let allow_shadowing = self.parent_scope.expansion == ExpnId::root();
1059 if let Some(span) = import_all {
1060 let import = macro_use_import(self, span);
1061 self.r.potentially_unused_imports.push(import);
1062 module.for_each_child(self, |this, ident, ns, binding| {
1064 let imported_binding = this.r.import(binding, import);
1065 this.add_macro_use_binding(ident.name, imported_binding, span, allow_shadowing);
1069 for ident in single_imports.iter().cloned() {
1070 let result = self.r.resolve_ident_in_module(
1071 ModuleOrUniformRoot::Module(module),
1078 if let Ok(binding) = result {
1079 let import = macro_use_import(self, ident.span);
1080 self.r.potentially_unused_imports.push(import);
1081 let imported_binding = self.r.import(binding, import);
1082 self.add_macro_use_binding(
1089 struct_span_err!(self.r.session, ident.span, E0469, "imported macro not found")
1094 import_all.is_some() || !single_imports.is_empty()
1097 /// Returns `true` if this attribute list contains `macro_use`.
1098 fn contains_macro_use(&mut self, attrs: &[ast::Attribute]) -> bool {
1100 if attr.check_name(sym::macro_escape) {
1101 let msg = "`#[macro_escape]` is a deprecated synonym for `#[macro_use]`";
1102 let mut err = self.r.session.struct_span_warn(attr.span, msg);
1103 if let ast::AttrStyle::Inner = attr.style {
1104 err.help("try an outer attribute: `#[macro_use]`").emit();
1108 } else if !attr.check_name(sym::macro_use) {
1112 if !attr.is_word() {
1113 self.r.session.span_err(attr.span, "arguments to `macro_use` are not allowed here");
1121 fn visit_invoc(&mut self, id: NodeId) -> MacroRulesScope<'a> {
1122 let invoc_id = id.placeholder_to_expn_id();
1124 self.parent_scope.module.unexpanded_invocations.borrow_mut().insert(invoc_id);
1126 let old_parent_scope = self.r.invocation_parent_scopes.insert(invoc_id, self.parent_scope);
1127 assert!(old_parent_scope.is_none(), "invocation data is reset for an invocation");
1129 MacroRulesScope::Invocation(invoc_id)
1132 fn proc_macro_stub(item: &ast::Item) -> Option<(MacroKind, Ident, Span)> {
1133 if attr::contains_name(&item.attrs, sym::proc_macro) {
1134 return Some((MacroKind::Bang, item.ident, item.span));
1135 } else if attr::contains_name(&item.attrs, sym::proc_macro_attribute) {
1136 return Some((MacroKind::Attr, item.ident, item.span));
1137 } else if let Some(attr) = attr::find_by_name(&item.attrs, sym::proc_macro_derive) {
1138 if let Some(nested_meta) = attr.meta_item_list().and_then(|list| list.get(0).cloned()) {
1139 if let Some(ident) = nested_meta.ident() {
1140 return Some((MacroKind::Derive, ident, ident.span));
1147 // Mark the given macro as unused unless its name starts with `_`.
1148 // Macro uses will remove items from this set, and the remaining
1149 // items will be reported as `unused_macros`.
1150 fn insert_unused_macro(
1157 if !ident.as_str().starts_with('_') {
1158 self.r.unused_macros.insert(def_id, (node_id, span));
1162 fn define_macro(&mut self, item: &ast::Item) -> MacroRulesScope<'a> {
1163 let parent_scope = self.parent_scope;
1164 let expansion = parent_scope.expansion;
1165 let def_id = self.r.local_def_id(item.id);
1166 let (ext, ident, span, macro_rules) = match &item.kind {
1167 ItemKind::MacroDef(def) => {
1168 let ext = Lrc::new(self.r.compile_macro(item, self.r.session.edition()));
1169 (ext, item.ident, item.span, def.macro_rules)
1171 ItemKind::Fn(..) => match Self::proc_macro_stub(item) {
1172 Some((macro_kind, ident, span)) => {
1173 self.r.proc_macro_stubs.insert(def_id);
1174 (self.r.dummy_ext(macro_kind), ident, span, false)
1176 None => return parent_scope.macro_rules,
1178 _ => unreachable!(),
1181 let res = Res::Def(DefKind::Macro(ext.macro_kind()), def_id.to_def_id());
1182 self.r.macro_map.insert(def_id.to_def_id(), ext);
1183 self.r.local_macro_def_scopes.insert(def_id, parent_scope.module);
1186 let ident = ident.normalize_to_macros_2_0();
1187 self.r.macro_names.insert(ident);
1188 let is_macro_export = attr::contains_name(&item.attrs, sym::macro_export);
1189 let vis = if is_macro_export {
1190 ty::Visibility::Public
1192 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
1194 let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas);
1195 self.r.set_binding_parent_module(binding, parent_scope.module);
1196 self.r.all_macros.insert(ident.name, res);
1197 if is_macro_export {
1198 let module = self.r.graph_root;
1199 self.r.define(module, ident, MacroNS, (res, vis, span, expansion, IsMacroExport));
1201 self.r.check_reserved_macro_name(ident, res);
1202 self.insert_unused_macro(ident, def_id, item.id, span);
1204 MacroRulesScope::Binding(self.r.arenas.alloc_macro_rules_binding(MacroRulesBinding {
1205 parent_macro_rules_scope: parent_scope.macro_rules,
1210 let module = parent_scope.module;
1211 let vis = match item.kind {
1212 // Visibilities must not be resolved non-speculatively twice
1213 // and we already resolved this one as a `fn` item visibility.
1214 ItemKind::Fn(..) => self
1215 .resolve_visibility_speculative(&item.vis, true)
1216 .unwrap_or(ty::Visibility::Public),
1217 _ => self.resolve_visibility(&item.vis),
1219 if vis != ty::Visibility::Public {
1220 self.insert_unused_macro(ident, def_id, item.id, span);
1222 self.r.define(module, ident, MacroNS, (res, vis, span, expansion));
1223 self.parent_scope.macro_rules
1228 macro_rules! method {
1229 ($visit:ident: $ty:ty, $invoc:path, $walk:ident) => {
1230 fn $visit(&mut self, node: &'b $ty) {
1231 if let $invoc(..) = node.kind {
1232 self.visit_invoc(node.id);
1234 visit::$walk(self, node);
1240 impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
1241 method!(visit_expr: ast::Expr, ast::ExprKind::MacCall, walk_expr);
1242 method!(visit_pat: ast::Pat, ast::PatKind::MacCall, walk_pat);
1243 method!(visit_ty: ast::Ty, ast::TyKind::MacCall, walk_ty);
1245 fn visit_item(&mut self, item: &'b Item) {
1246 let macro_use = match item.kind {
1247 ItemKind::MacroDef(..) => {
1248 self.parent_scope.macro_rules = self.define_macro(item);
1251 ItemKind::MacCall(..) => {
1252 self.parent_scope.macro_rules = self.visit_invoc(item.id);
1255 ItemKind::Mod(..) => self.contains_macro_use(&item.attrs),
1258 let orig_current_module = self.parent_scope.module;
1259 let orig_current_macro_rules_scope = self.parent_scope.macro_rules;
1260 self.build_reduced_graph_for_item(item);
1261 visit::walk_item(self, item);
1262 self.parent_scope.module = orig_current_module;
1264 self.parent_scope.macro_rules = orig_current_macro_rules_scope;
1268 fn visit_stmt(&mut self, stmt: &'b ast::Stmt) {
1269 if let ast::StmtKind::MacCall(..) = stmt.kind {
1270 self.parent_scope.macro_rules = self.visit_invoc(stmt.id);
1272 visit::walk_stmt(self, stmt);
1276 fn visit_foreign_item(&mut self, foreign_item: &'b ForeignItem) {
1277 if let ForeignItemKind::MacCall(_) = foreign_item.kind {
1278 self.visit_invoc(foreign_item.id);
1282 self.build_reduced_graph_for_foreign_item(foreign_item);
1283 visit::walk_foreign_item(self, foreign_item);
1286 fn visit_block(&mut self, block: &'b Block) {
1287 let orig_current_module = self.parent_scope.module;
1288 let orig_current_macro_rules_scope = self.parent_scope.macro_rules;
1289 self.build_reduced_graph_for_block(block);
1290 visit::walk_block(self, block);
1291 self.parent_scope.module = orig_current_module;
1292 self.parent_scope.macro_rules = orig_current_macro_rules_scope;
1295 fn visit_assoc_item(&mut self, item: &'b AssocItem, ctxt: AssocCtxt) {
1296 let parent = self.parent_scope.module;
1298 if let AssocItemKind::MacCall(_) = item.kind {
1299 self.visit_invoc(item.id);
1303 if let AssocCtxt::Impl = ctxt {
1304 self.resolve_visibility(&item.vis);
1305 visit::walk_assoc_item(self, item, ctxt);
1309 // Add the item to the trait info.
1310 let item_def_id = self.r.local_def_id(item.id).to_def_id();
1311 let (res, ns) = match item.kind {
1312 AssocItemKind::Const(..) => (Res::Def(DefKind::AssocConst, item_def_id), ValueNS),
1313 AssocItemKind::Fn(_, ref sig, _, _) => {
1314 if sig.decl.has_self() {
1315 self.r.has_self.insert(item_def_id);
1317 (Res::Def(DefKind::AssocFn, item_def_id), ValueNS)
1319 AssocItemKind::TyAlias(..) => (Res::Def(DefKind::AssocTy, item_def_id), TypeNS),
1320 AssocItemKind::MacCall(_) => bug!(), // handled above
1323 let vis = ty::Visibility::Public;
1324 let expansion = self.parent_scope.expansion;
1325 self.r.define(parent, item.ident, ns, (res, vis, item.span, expansion));
1327 visit::walk_assoc_item(self, item, ctxt);
1330 fn visit_token(&mut self, t: Token) {
1331 if let token::Interpolated(nt) = t.kind {
1332 if let token::NtExpr(ref expr) = *nt {
1333 if let ast::ExprKind::MacCall(..) = expr.kind {
1334 self.visit_invoc(expr.id);
1340 fn visit_attribute(&mut self, attr: &'b ast::Attribute) {
1341 if !attr.is_doc_comment() && attr::is_builtin_attr(attr) {
1344 .push((attr.get_normal_item().path.segments[0].ident, self.parent_scope));
1346 visit::walk_attribute(self, attr);
1349 fn visit_arm(&mut self, arm: &'b ast::Arm) {
1350 if arm.is_placeholder {
1351 self.visit_invoc(arm.id);
1353 visit::walk_arm(self, arm);
1357 fn visit_field(&mut self, f: &'b ast::Field) {
1358 if f.is_placeholder {
1359 self.visit_invoc(f.id);
1361 visit::walk_field(self, f);
1365 fn visit_field_pattern(&mut self, fp: &'b ast::FieldPat) {
1366 if fp.is_placeholder {
1367 self.visit_invoc(fp.id);
1369 visit::walk_field_pattern(self, fp);
1373 fn visit_generic_param(&mut self, param: &'b ast::GenericParam) {
1374 if param.is_placeholder {
1375 self.visit_invoc(param.id);
1377 visit::walk_generic_param(self, param);
1381 fn visit_param(&mut self, p: &'b ast::Param) {
1382 if p.is_placeholder {
1383 self.visit_invoc(p.id);
1385 visit::walk_param(self, p);
1389 fn visit_struct_field(&mut self, sf: &'b ast::StructField) {
1390 if sf.is_placeholder {
1391 self.visit_invoc(sf.id);
1393 self.resolve_visibility(&sf.vis);
1394 visit::walk_struct_field(self, sf);
1398 // Constructs the reduced graph for one variant. Variants exist in the
1399 // type and value namespaces.
1400 fn visit_variant(&mut self, variant: &'b ast::Variant) {
1401 if variant.is_placeholder {
1402 self.visit_invoc(variant.id);
1406 let parent = self.parent_scope.module;
1407 let vis = self.r.variant_vis[&parent.def_id().expect("enum without def-id")];
1408 let expn_id = self.parent_scope.expansion;
1409 let ident = variant.ident;
1411 // Define a name in the type namespace.
1412 let def_id = self.r.local_def_id(variant.id).to_def_id();
1413 let res = Res::Def(DefKind::Variant, def_id);
1414 self.r.define(parent, ident, TypeNS, (res, vis, variant.span, expn_id));
1416 // If the variant is marked as non_exhaustive then lower the visibility to within the
1418 let mut ctor_vis = vis;
1419 let has_non_exhaustive = attr::contains_name(&variant.attrs, sym::non_exhaustive);
1420 if has_non_exhaustive && vis == ty::Visibility::Public {
1421 ctor_vis = ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX));
1424 // Define a constructor name in the value namespace.
1425 // Braced variants, unlike structs, generate unusable names in
1426 // value namespace, they are reserved for possible future use.
1427 // It's ok to use the variant's id as a ctor id since an
1428 // error will be reported on any use of such resolution anyway.
1429 let ctor_node_id = variant.data.ctor_id().unwrap_or(variant.id);
1430 let ctor_def_id = self.r.local_def_id(ctor_node_id).to_def_id();
1431 let ctor_kind = CtorKind::from_ast(&variant.data);
1432 let ctor_res = Res::Def(DefKind::Ctor(CtorOf::Variant, ctor_kind), ctor_def_id);
1433 self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, variant.span, expn_id));
1434 // Record field names for error reporting.
1435 self.insert_field_names_local(ctor_def_id, &variant.data);
1437 visit::walk_variant(self, variant);