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, PathResult, ResolutionError, VisResolutionError};
14 ExternPreludeEntry, ModuleOrUniformRoot, ParentScope, PerNS, Resolver, ResolverArenas,
16 use crate::{Module, ModuleData, ModuleKind, NameBinding, NameBindingKind, Segment, ToNameBinding};
18 use rustc_ast::visit::{self, AssocCtxt, Visitor};
19 use rustc_ast::{self as ast, AssocItem, AssocItemKind, MetaItemKind, StmtKind};
20 use rustc_ast::{Block, FnKind, ForeignItem, ForeignItemKind, ImplKind, Item, ItemKind, NodeId};
21 use rustc_ast_lowering::ResolverAstLowering;
22 use rustc_attr as attr;
23 use rustc_data_structures::sync::Lrc;
24 use rustc_errors::{struct_span_err, Applicability};
25 use rustc_expand::base::SyntaxExtension;
26 use rustc_expand::expand::AstFragment;
27 use rustc_hir::def::{self, *};
28 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX};
29 use rustc_metadata::creader::LoadedMacro;
30 use rustc_middle::bug;
31 use rustc_middle::hir::exports::Export;
32 use rustc_middle::middle::cstore::CrateStore;
34 use rustc_span::hygiene::{ExpnId, MacroKind};
35 use rustc_span::source_map::{respan, Spanned};
36 use rustc_span::symbol::{kw, sym, Ident, Symbol};
43 type Res = def::Res<NodeId>;
45 impl<'a> ToNameBinding<'a> for (Module<'a>, ty::Visibility, Span, ExpnId) {
46 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
47 arenas.alloc_name_binding(NameBinding {
48 kind: NameBindingKind::Module(self.0),
57 impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, ExpnId) {
58 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
59 arenas.alloc_name_binding(NameBinding {
60 kind: NameBindingKind::Res(self.0, false),
71 impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, ExpnId, IsMacroExport) {
72 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
73 arenas.alloc_name_binding(NameBinding {
74 kind: NameBindingKind::Res(self.0, true),
83 impl<'a> Resolver<'a> {
84 /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
85 /// otherwise, reports an error.
86 crate fn define<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
90 let binding = def.to_name_binding(self.arenas);
91 let key = self.new_key(ident, ns);
92 if let Err(old_binding) = self.try_define(parent, key, binding) {
93 self.report_conflict(parent, ident, ns, old_binding, &binding);
97 /// Walks up the tree of definitions starting at `def_id`,
98 /// stopping at the first `DefKind::Mod` encountered
99 fn nearest_parent_mod(&mut self, def_id: DefId) -> Module<'a> {
100 let def_key = self.cstore().def_key(def_id);
102 let mut parent_id = DefId {
104 index: def_key.parent.expect("failed to get parent for module"),
106 // The immediate parent may not be a module
107 // (e.g. `const _: () = { #[path = "foo.rs"] mod foo; };`)
108 // Walk up the tree until we hit a module or the crate root.
109 while parent_id.index != CRATE_DEF_INDEX
110 && self.cstore().def_kind(parent_id) != DefKind::Mod
112 let parent_def_key = self.cstore().def_key(parent_id);
113 parent_id.index = parent_def_key.parent.expect("failed to get parent for module");
115 self.get_module(parent_id)
118 pub fn get_module(&mut self, def_id: DefId) -> Module<'a> {
119 // If this is a local module, it will be in `module_map`, no need to recalculate it.
120 if let Some(def_id) = def_id.as_local() {
121 return self.module_map[&def_id];
124 // Cache module resolution
125 if let Some(&module) = self.extern_module_map.get(&def_id) {
129 let (name, parent) = if def_id.index == CRATE_DEF_INDEX {
130 // This is the crate root
131 (self.cstore().crate_name_untracked(def_id.krate), None)
133 let def_key = self.cstore().def_key(def_id);
138 .expect("given a DefId that wasn't a module");
140 let parent = Some(self.nearest_parent_mod(def_id));
144 // Allocate and return a new module with the information we found
145 let kind = ModuleKind::Def(DefKind::Mod, def_id, name);
146 let module = self.arenas.alloc_module(ModuleData::new(
150 self.cstore().module_expansion_untracked(def_id, &self.session),
151 self.cstore().get_span_untracked(def_id, &self.session),
153 self.extern_module_map.insert(def_id, module);
157 crate fn macro_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
158 let def_id = match expn_id.expn_data().macro_def_id {
159 Some(def_id) => def_id,
160 None => return self.ast_transform_scopes.get(&expn_id).unwrap_or(&self.graph_root),
162 if let Some(id) = def_id.as_local() {
163 self.local_macro_def_scopes[&id]
165 // This is not entirely correct - a `macro_rules!` macro may occur
166 // inside a 'block' module:
171 // macro_rules! my_macro {
175 // We don't record this information for external crates, so
176 // the module we compute here will be the closest 'mod' item
177 // (not necesssarily the actual parent of the `macro_rules!`
178 // macro). `macro_rules!` macros can't use def-site hygiene,
179 // so this hopefully won't be a problem.
181 // See https://github.com/rust-lang/rust/pull/77984#issuecomment-712445508
182 self.nearest_parent_mod(def_id)
186 crate fn get_macro(&mut self, res: Res) -> Option<Lrc<SyntaxExtension>> {
188 Res::Def(DefKind::Macro(..), def_id) => Some(self.get_macro_by_def_id(def_id)),
189 Res::NonMacroAttr(attr_kind) => Some(self.non_macro_attr(attr_kind.is_used())),
194 crate fn get_macro_by_def_id(&mut self, def_id: DefId) -> Lrc<SyntaxExtension> {
195 if let Some(ext) = self.macro_map.get(&def_id) {
199 let ext = Lrc::new(match self.cstore().load_macro_untracked(def_id, &self.session) {
200 LoadedMacro::MacroDef(item, edition) => self.compile_macro(&item, edition),
201 LoadedMacro::ProcMacro(ext) => ext,
204 self.macro_map.insert(def_id, ext.clone());
208 crate fn build_reduced_graph(
210 fragment: &AstFragment,
211 parent_scope: ParentScope<'a>,
212 ) -> MacroRulesScopeRef<'a> {
213 collect_definitions(self, fragment, parent_scope.expansion);
214 let mut visitor = BuildReducedGraphVisitor { r: self, parent_scope };
215 fragment.visit_with(&mut visitor);
216 visitor.parent_scope.macro_rules
219 crate fn build_reduced_graph_external(&mut self, module: Module<'a>) {
220 let def_id = module.def_id().expect("unpopulated module without a def-id");
221 for child in self.cstore().item_children_untracked(def_id, self.session) {
222 let child = child.map_id(|_| panic!("unexpected id"));
223 let parent_scope = ParentScope::module(module, self);
224 BuildReducedGraphVisitor { r: self, parent_scope }
225 .build_reduced_graph_for_external_crate_res(child);
230 struct BuildReducedGraphVisitor<'a, 'b> {
231 r: &'b mut Resolver<'a>,
232 parent_scope: ParentScope<'a>,
235 impl<'a> AsMut<Resolver<'a>> for BuildReducedGraphVisitor<'a, '_> {
236 fn as_mut(&mut self) -> &mut Resolver<'a> {
241 impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
242 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
243 self.resolve_visibility_speculative(vis, false).unwrap_or_else(|err| {
244 self.r.report_vis_error(err);
245 ty::Visibility::Public
249 fn resolve_visibility_speculative<'ast>(
251 vis: &'ast ast::Visibility,
253 ) -> Result<ty::Visibility, VisResolutionError<'ast>> {
254 let parent_scope = &self.parent_scope;
256 ast::VisibilityKind::Public => Ok(ty::Visibility::Public),
257 ast::VisibilityKind::Crate(..) => {
258 Ok(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)))
260 ast::VisibilityKind::Inherited => {
261 if matches!(self.parent_scope.module.kind, ModuleKind::Def(DefKind::Enum, _, _)) {
262 // Any inherited visibility resolved directly inside an enum
263 // (e.g. variants or fields) inherits from the visibility of the enum.
264 let parent_enum = self.parent_scope.module.def_id().unwrap().expect_local();
265 Ok(self.r.visibilities[&parent_enum])
267 // If it's not in an enum, its visibility is restricted to the `mod` item
268 // that it's defined in.
269 Ok(ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod))
272 ast::VisibilityKind::Restricted { ref path, id, .. } => {
273 // For visibilities we are not ready to provide correct implementation of "uniform
274 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
275 // On 2015 edition visibilities are resolved as crate-relative by default,
276 // so we are prepending a root segment if necessary.
277 let ident = path.segments.get(0).expect("empty path in visibility").ident;
278 let crate_root = if ident.is_path_segment_keyword() {
280 } else if ident.span.rust_2015() {
281 Some(Segment::from_ident(Ident::new(
283 path.span.shrink_to_lo().with_ctxt(ident.span.ctxt()),
286 return Err(VisResolutionError::Relative2018(ident.span, path));
289 let segments = crate_root
291 .chain(path.segments.iter().map(|seg| seg.into()))
292 .collect::<Vec<_>>();
293 let expected_found_error = |res| {
294 Err(VisResolutionError::ExpectedFound(
296 Segment::names_to_string(&segments),
300 match self.r.resolve_path(
306 CrateLint::SimplePath(id),
308 PathResult::Module(ModuleOrUniformRoot::Module(module)) => {
309 let res = module.res().expect("visibility resolved to unnamed block");
311 self.r.record_partial_res(id, PartialRes::new(res));
313 if module.is_normal() {
315 Ok(ty::Visibility::Public)
317 let vis = ty::Visibility::Restricted(res.def_id());
318 if self.r.is_accessible_from(vis, parent_scope.module) {
321 Err(VisResolutionError::AncestorOnly(path.span))
325 expected_found_error(res)
328 PathResult::Module(..) => Err(VisResolutionError::ModuleOnly(path.span)),
329 PathResult::NonModule(partial_res) => {
330 expected_found_error(partial_res.base_res())
332 PathResult::Failed { span, label, suggestion, .. } => {
333 Err(VisResolutionError::FailedToResolve(span, label, suggestion))
335 PathResult::Indeterminate => Err(VisResolutionError::Indeterminate(path.span)),
341 fn insert_field_names_local(&mut self, def_id: DefId, vdata: &ast::VariantData) {
342 let field_names = vdata
345 .map(|field| respan(field.span, field.ident.map_or(kw::Empty, |ident| ident.name)))
347 self.insert_field_names(def_id, field_names);
350 fn insert_field_names(&mut self, def_id: DefId, field_names: Vec<Spanned<Symbol>>) {
351 self.r.field_names.insert(def_id, field_names);
354 fn block_needs_anonymous_module(&mut self, block: &Block) -> bool {
355 // If any statements are items, we need to create an anonymous module
359 .any(|statement| matches!(statement.kind, StmtKind::Item(_) | StmtKind::MacCall(_)))
362 // Add an import to the current module.
365 module_path: Vec<Segment>,
366 kind: ImportKind<'a>,
374 let current_module = self.parent_scope.module;
375 let import = self.r.arenas.alloc_import(Import {
377 parent_scope: self.parent_scope,
379 imported_module: Cell::new(None),
383 use_span_with_attributes: item.span_with_attributes(),
384 has_attributes: !item.attrs.is_empty(),
388 used: Cell::new(false),
391 debug!("add_import({:?})", import);
393 self.r.indeterminate_imports.push(import);
395 // Don't add unresolved underscore imports to modules
396 ImportKind::Single { target: Ident { name: kw::Underscore, .. }, .. } => {}
397 ImportKind::Single { target, type_ns_only, .. } => {
398 self.r.per_ns(|this, ns| {
399 if !type_ns_only || ns == TypeNS {
400 let key = this.new_key(target, ns);
401 let mut resolution = this.resolution(current_module, key).borrow_mut();
402 resolution.add_single_import(import);
406 // We don't add prelude imports to the globs since they only affect lexical scopes,
407 // which are not relevant to import resolution.
408 ImportKind::Glob { is_prelude: true, .. } => {}
409 ImportKind::Glob { .. } => current_module.globs.borrow_mut().push(import),
414 fn build_reduced_graph_for_use_tree(
416 // This particular use tree
417 use_tree: &ast::UseTree,
419 parent_prefix: &[Segment],
421 // The whole `use` item
427 "build_reduced_graph_for_use_tree(parent_prefix={:?}, use_tree={:?}, nested={})",
428 parent_prefix, use_tree, nested
431 let mut prefix_iter = parent_prefix
434 .chain(use_tree.prefix.segments.iter().map(|seg| seg.into()))
437 // On 2015 edition imports are resolved as crate-relative by default,
438 // so prefixes are prepended with crate root segment if necessary.
439 // The root is prepended lazily, when the first non-empty prefix or terminating glob
440 // appears, so imports in braced groups can have roots prepended independently.
441 let is_glob = matches!(use_tree.kind, ast::UseTreeKind::Glob);
442 let crate_root = match prefix_iter.peek() {
443 Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.rust_2015() => {
444 Some(seg.ident.span.ctxt())
446 None if is_glob && use_tree.span.rust_2015() => Some(use_tree.span.ctxt()),
450 Segment::from_ident(Ident::new(
452 use_tree.prefix.span.shrink_to_lo().with_ctxt(ctxt),
456 let prefix = crate_root.into_iter().chain(prefix_iter).collect::<Vec<_>>();
457 debug!("build_reduced_graph_for_use_tree: prefix={:?}", prefix);
459 let empty_for_self = |prefix: &[Segment]| {
460 prefix.is_empty() || prefix.len() == 1 && prefix[0].ident.name == kw::PathRoot
462 match use_tree.kind {
463 ast::UseTreeKind::Simple(rename, ..) => {
464 let mut ident = use_tree.ident();
465 let mut module_path = prefix;
466 let mut source = module_path.pop().unwrap();
467 let mut type_ns_only = false;
470 // Correctly handle `self`
471 if source.ident.name == kw::SelfLower {
474 if empty_for_self(&module_path) {
477 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix,
482 // Replace `use foo::{ self };` with `use foo;`
483 source = module_path.pop().unwrap();
484 if rename.is_none() {
485 ident = source.ident;
490 if source.ident.name == kw::SelfLower {
491 let parent = module_path.last();
493 let span = match parent {
494 // only `::self` from `use foo::self as bar`
495 Some(seg) => seg.ident.span.shrink_to_hi().to(source.ident.span),
496 None => source.ident.span,
498 let span_with_rename = match rename {
499 // only `self as bar` from `use foo::self as bar`
500 Some(rename) => source.ident.span.to(rename.span),
501 None => source.ident.span,
505 ResolutionError::SelfImportsOnlyAllowedWithin {
506 root: parent.is_none(),
511 // Error recovery: replace `use foo::self;` with `use foo;`
512 if let Some(parent) = module_path.pop() {
514 if rename.is_none() {
515 ident = source.ident;
520 // Disallow `use $crate;`
521 if source.ident.name == kw::DollarCrate && module_path.is_empty() {
522 let crate_root = self.r.resolve_crate_root(source.ident);
523 let crate_name = match crate_root.kind {
524 ModuleKind::Def(.., name) => name,
525 ModuleKind::Block(..) => unreachable!(),
527 // HACK(eddyb) unclear how good this is, but keeping `$crate`
528 // in `source` breaks `src/test/ui/imports/import-crate-var.rs`,
529 // while the current crate doesn't have a valid `crate_name`.
530 if crate_name != kw::Empty {
531 // `crate_name` should not be interpreted as relative.
532 module_path.push(Segment {
533 ident: Ident { name: kw::PathRoot, span: source.ident.span },
534 id: Some(self.r.next_node_id()),
535 has_generic_args: false,
537 source.ident.name = crate_name;
539 if rename.is_none() {
540 ident.name = crate_name;
545 .struct_span_err(item.span, "`$crate` may not be imported")
550 if ident.name == kw::Crate {
551 self.r.session.span_err(
553 "crate root imports need to be explicitly named: \
554 `use crate as name;`",
558 let kind = ImportKind::Single {
559 source: source.ident,
561 source_bindings: PerNS {
562 type_ns: Cell::new(Err(Determinacy::Undetermined)),
563 value_ns: Cell::new(Err(Determinacy::Undetermined)),
564 macro_ns: Cell::new(Err(Determinacy::Undetermined)),
566 target_bindings: PerNS {
567 type_ns: Cell::new(None),
568 value_ns: Cell::new(None),
569 macro_ns: Cell::new(None),
585 ast::UseTreeKind::Glob => {
586 let kind = ImportKind::Glob {
587 is_prelude: self.r.session.contains_name(&item.attrs, sym::prelude_import),
588 max_vis: Cell::new(ty::Visibility::Invisible),
590 self.add_import(prefix, kind, use_tree.span, id, item, root_span, item.id, vis);
592 ast::UseTreeKind::Nested(ref items) => {
593 // Ensure there is at most one `self` in the list
594 let self_spans = items
596 .filter_map(|&(ref use_tree, _)| {
597 if let ast::UseTreeKind::Simple(..) = use_tree.kind {
598 if use_tree.ident().name == kw::SelfLower {
599 return Some(use_tree.span);
605 .collect::<Vec<_>>();
606 if self_spans.len() > 1 {
607 let mut e = self.r.into_struct_error(
609 ResolutionError::SelfImportCanOnlyAppearOnceInTheList,
612 for other_span in self_spans.iter().skip(1) {
613 e.span_label(*other_span, "another `self` import appears here");
619 for &(ref tree, id) in items {
620 self.build_reduced_graph_for_use_tree(
621 // This particular use tree
622 tree, id, &prefix, true, // The whole `use` item
623 item, vis, root_span,
627 // Empty groups `a::b::{}` are turned into synthetic `self` imports
628 // `a::b::c::{self as _}`, so that their prefixes are correctly
629 // resolved and checked for privacy/stability/etc.
630 if items.is_empty() && !empty_for_self(&prefix) {
631 let new_span = prefix[prefix.len() - 1].ident.span;
632 let tree = ast::UseTree {
633 prefix: ast::Path::from_ident(Ident::new(kw::SelfLower, new_span)),
634 kind: ast::UseTreeKind::Simple(
635 Some(Ident::new(kw::Underscore, new_span)),
641 self.build_reduced_graph_for_use_tree(
642 // This particular use tree
647 // The whole `use` item
649 ty::Visibility::Invisible,
657 /// Constructs the reduced graph for one item.
658 fn build_reduced_graph_for_item(&mut self, item: &'b Item) {
659 if matches!(item.kind, ItemKind::Mod(..)) && item.ident.name == kw::Empty {
660 // Fake crate root item from expand.
664 let parent_scope = &self.parent_scope;
665 let parent = parent_scope.module;
666 let expansion = parent_scope.expansion;
667 let ident = item.ident;
669 let vis = self.resolve_visibility(&item.vis);
670 let local_def_id = self.r.local_def_id(item.id);
671 let def_id = local_def_id.to_def_id();
673 self.r.visibilities.insert(local_def_id, vis);
676 ItemKind::Use(ref use_tree) => {
677 self.build_reduced_graph_for_use_tree(
678 // This particular use tree
683 // The whole `use` item
690 ItemKind::ExternCrate(orig_name) => {
691 let module = if orig_name.is_none() && ident.name == kw::SelfLower {
694 .struct_span_err(item.span, "`extern crate self;` requires renaming")
698 "extern crate self as name;".into(),
699 Applicability::HasPlaceholders,
703 } else if orig_name == Some(kw::SelfLower) {
706 let crate_id = self.r.crate_loader.process_extern_crate(
711 self.r.extern_crate_map.insert(local_def_id, crate_id);
712 self.r.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX })
715 let used = self.process_macro_use_imports(item, module);
717 (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.r.arenas);
718 let import = self.r.arenas.alloc_import(Import {
719 kind: ImportKind::ExternCrate { source: orig_name, target: ident },
722 parent_scope: self.parent_scope,
723 imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
724 has_attributes: !item.attrs.is_empty(),
725 use_span_with_attributes: item.span_with_attributes(),
727 root_span: item.span,
729 module_path: Vec::new(),
731 used: Cell::new(used),
733 self.r.potentially_unused_imports.push(import);
734 let imported_binding = self.r.import(binding, import);
735 if ptr::eq(parent, self.r.graph_root) {
736 if let Some(entry) = self.r.extern_prelude.get(&ident.normalize_to_macros_2_0())
738 if expansion != ExpnId::root()
739 && orig_name.is_some()
740 && entry.extern_crate_item.is_none()
742 let msg = "macro-expanded `extern crate` items cannot \
743 shadow names passed with `--extern`";
744 self.r.session.span_err(item.span, msg);
748 self.r.extern_prelude.entry(ident.normalize_to_macros_2_0()).or_insert(
750 extern_crate_item: None,
751 introduced_by_item: true,
754 entry.extern_crate_item = Some(imported_binding);
755 if orig_name.is_some() {
756 entry.introduced_by_item = true;
759 self.r.define(parent, ident, TypeNS, imported_binding);
762 ItemKind::Mod(..) => {
763 let module_kind = ModuleKind::Def(DefKind::Mod, def_id, ident.name);
764 let module = self.r.arenas.alloc_module(ModuleData {
765 no_implicit_prelude: parent.no_implicit_prelude || {
766 self.r.session.contains_name(&item.attrs, sym::no_implicit_prelude)
768 ..ModuleData::new(Some(parent), module_kind, def_id, expansion, item.span)
770 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
771 self.r.module_map.insert(local_def_id, module);
773 // Descend into the module.
774 self.parent_scope.module = module;
777 // These items live in the value namespace.
778 ItemKind::Static(..) => {
779 let res = Res::Def(DefKind::Static, def_id);
780 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
782 ItemKind::Const(..) => {
783 let res = Res::Def(DefKind::Const, def_id);
784 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
786 ItemKind::Fn(..) => {
787 let res = Res::Def(DefKind::Fn, def_id);
788 self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
790 // Functions introducing procedural macros reserve a slot
791 // in the macro namespace as well (see #52225).
792 self.define_macro(item);
795 // These items live in the type namespace.
796 ItemKind::TyAlias(..) => {
797 let res = Res::Def(DefKind::TyAlias, def_id);
798 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
801 ItemKind::Enum(_, _) => {
802 let module_kind = ModuleKind::Def(DefKind::Enum, def_id, ident.name);
803 let module = self.r.new_module(
806 parent.nearest_parent_mod,
810 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
811 self.parent_scope.module = module;
814 ItemKind::TraitAlias(..) => {
815 let res = Res::Def(DefKind::TraitAlias, def_id);
816 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
819 // These items live in both the type and value namespaces.
820 ItemKind::Struct(ref vdata, _) => {
821 // Define a name in the type namespace.
822 let res = Res::Def(DefKind::Struct, def_id);
823 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
825 // Record field names for error reporting.
826 self.insert_field_names_local(def_id, vdata);
828 // If this is a tuple or unit struct, define a name
829 // in the value namespace as well.
830 if let Some(ctor_node_id) = vdata.ctor_id() {
831 // If the structure is marked as non_exhaustive then lower the visibility
832 // to within the crate.
833 let mut ctor_vis = if vis == ty::Visibility::Public
834 && self.r.session.contains_name(&item.attrs, sym::non_exhaustive)
836 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
841 let mut ret_fields = Vec::with_capacity(vdata.fields().len());
843 for field in vdata.fields() {
844 // NOTE: The field may be an expansion placeholder, but expansion sets
845 // correct visibilities for unnamed field placeholders specifically, so the
846 // constructor visibility should still be determined correctly.
848 .resolve_visibility_speculative(&field.vis, true)
849 .unwrap_or(ty::Visibility::Public);
850 if ctor_vis.is_at_least(field_vis, &*self.r) {
851 ctor_vis = field_vis;
853 ret_fields.push(field_vis);
855 let ctor_def_id = self.r.local_def_id(ctor_node_id);
856 let ctor_res = Res::Def(
857 DefKind::Ctor(CtorOf::Struct, CtorKind::from_ast(vdata)),
858 ctor_def_id.to_def_id(),
860 self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion));
861 self.r.visibilities.insert(ctor_def_id, ctor_vis);
863 self.r.struct_constructors.insert(def_id, (ctor_res, ctor_vis, ret_fields));
867 ItemKind::Union(ref vdata, _) => {
868 let res = Res::Def(DefKind::Union, def_id);
869 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
871 // Record field names for error reporting.
872 self.insert_field_names_local(def_id, vdata);
875 ItemKind::Trait(..) => {
876 // Add all the items within to a new module.
877 let module_kind = ModuleKind::Def(DefKind::Trait, def_id, ident.name);
878 let module = self.r.new_module(
881 parent.nearest_parent_mod,
885 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
886 self.parent_scope.module = module;
889 // These items do not add names to modules.
890 ItemKind::Impl(box ImplKind { of_trait: Some(..), .. }) => {
891 self.r.trait_impl_items.insert(local_def_id);
893 ItemKind::Impl { .. } | ItemKind::ForeignMod(..) | ItemKind::GlobalAsm(..) => {}
895 ItemKind::MacroDef(..) | ItemKind::MacCall(_) => unreachable!(),
899 /// Constructs the reduced graph for one foreign item.
900 fn build_reduced_graph_for_foreign_item(&mut self, item: &ForeignItem) {
901 let local_def_id = self.r.local_def_id(item.id);
902 let def_id = local_def_id.to_def_id();
903 let (def_kind, ns) = match item.kind {
904 ForeignItemKind::Fn(..) => (DefKind::Fn, ValueNS),
905 ForeignItemKind::Static(..) => (DefKind::Static, ValueNS),
906 ForeignItemKind::TyAlias(..) => (DefKind::ForeignTy, TypeNS),
907 ForeignItemKind::MacCall(_) => unreachable!(),
909 let parent = self.parent_scope.module;
910 let expansion = self.parent_scope.expansion;
911 let vis = self.resolve_visibility(&item.vis);
912 let res = Res::Def(def_kind, def_id);
913 self.r.define(parent, item.ident, ns, (res, vis, item.span, expansion));
914 self.r.visibilities.insert(local_def_id, vis);
917 fn build_reduced_graph_for_block(&mut self, block: &Block) {
918 let parent = self.parent_scope.module;
919 let expansion = self.parent_scope.expansion;
920 if self.block_needs_anonymous_module(block) {
921 let module = self.r.new_module(
923 ModuleKind::Block(block.id),
924 parent.nearest_parent_mod,
928 self.r.block_map.insert(block.id, module);
929 self.parent_scope.module = module; // Descend into the block.
933 /// Builds the reduced graph for a single item in an external crate.
934 fn build_reduced_graph_for_external_crate_res(&mut self, child: Export<NodeId>) {
935 let parent = self.parent_scope.module;
936 let Export { ident, res, vis, span } = child;
937 let expansion = self.parent_scope.expansion;
938 // Record primary definitions.
940 Res::Def(kind @ (DefKind::Mod | DefKind::Enum | DefKind::Trait), def_id) => {
941 let module = self.r.new_module(
943 ModuleKind::Def(kind, def_id, ident.name),
948 self.r.define(parent, ident, TypeNS, (module, vis, span, expansion));
957 | DefKind::TraitAlias
962 | Res::ToolMod => self.r.define(parent, ident, TypeNS, (res, vis, span, expansion)),
968 | DefKind::AssocConst
971 ) => self.r.define(parent, ident, ValueNS, (res, vis, span, expansion)),
972 Res::Def(DefKind::Macro(..), _) | Res::NonMacroAttr(..) => {
973 self.r.define(parent, ident, MacroNS, (res, vis, span, expansion))
977 | DefKind::ConstParam
978 | DefKind::ExternCrate
980 | DefKind::ForeignMod
983 | DefKind::LifetimeParam
987 | DefKind::Generator,
993 | Res::Err => bug!("unexpected resolution: {:?}", res),
995 // Record some extra data for better diagnostics.
996 let cstore = self.r.cstore();
998 Res::Def(DefKind::Struct | DefKind::Union, def_id) => {
999 let field_names = cstore.struct_field_names_untracked(def_id, self.r.session);
1000 self.insert_field_names(def_id, field_names);
1002 Res::Def(DefKind::AssocFn, def_id) => {
1004 .associated_item_cloned_untracked(def_id, self.r.session)
1005 .fn_has_self_parameter
1007 self.r.has_self.insert(def_id);
1010 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), def_id) => {
1011 let parent = cstore.def_key(def_id).parent;
1012 if let Some(struct_def_id) = parent.map(|index| DefId { index, ..def_id }) {
1013 self.r.struct_constructors.insert(struct_def_id, (res, vis, vec![]));
1020 fn add_macro_use_binding(
1023 binding: &'a NameBinding<'a>,
1025 allow_shadowing: bool,
1027 if self.r.macro_use_prelude.insert(name, binding).is_some() && !allow_shadowing {
1028 let msg = format!("`{}` is already in scope", name);
1030 "macro-expanded `#[macro_use]`s may not shadow existing macros (see RFC 1560)";
1031 self.r.session.struct_span_err(span, &msg).note(note).emit();
1035 /// Returns `true` if we should consider the underlying `extern crate` to be used.
1036 fn process_macro_use_imports(&mut self, item: &Item, module: Module<'a>) -> bool {
1037 let mut import_all = None;
1038 let mut single_imports = Vec::new();
1039 for attr in &item.attrs {
1040 if self.r.session.check_name(attr, sym::macro_use) {
1041 if self.parent_scope.module.parent.is_some() {
1046 "an `extern crate` loading macros must be at the crate root"
1050 if let ItemKind::ExternCrate(Some(orig_name)) = item.kind {
1051 if orig_name == kw::SelfLower {
1056 "`#[macro_use]` is not supported on `extern crate self`",
1062 |span| struct_span_err!(self.r.session, span, E0466, "bad macro import").emit();
1064 Some(meta) => match meta.kind {
1065 MetaItemKind::Word => {
1066 import_all = Some(meta.span);
1069 MetaItemKind::List(nested_metas) => {
1070 for nested_meta in nested_metas {
1071 match nested_meta.ident() {
1072 Some(ident) if nested_meta.is_word() => {
1073 single_imports.push(ident)
1075 _ => ill_formed(nested_meta.span()),
1079 MetaItemKind::NameValue(..) => ill_formed(meta.span),
1081 None => ill_formed(attr.span),
1086 let macro_use_import = |this: &Self, span| {
1087 this.r.arenas.alloc_import(Import {
1088 kind: ImportKind::MacroUse,
1091 parent_scope: this.parent_scope,
1092 imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
1093 use_span_with_attributes: item.span_with_attributes(),
1094 has_attributes: !item.attrs.is_empty(),
1095 use_span: item.span,
1098 module_path: Vec::new(),
1099 vis: Cell::new(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))),
1100 used: Cell::new(false),
1104 let allow_shadowing = self.parent_scope.expansion == ExpnId::root();
1105 if let Some(span) = import_all {
1106 let import = macro_use_import(self, span);
1107 self.r.potentially_unused_imports.push(import);
1108 module.for_each_child(self, |this, ident, ns, binding| {
1110 let imported_binding = this.r.import(binding, import);
1111 this.add_macro_use_binding(ident.name, imported_binding, span, allow_shadowing);
1115 for ident in single_imports.iter().cloned() {
1116 let result = self.r.resolve_ident_in_module(
1117 ModuleOrUniformRoot::Module(module),
1124 if let Ok(binding) = result {
1125 let import = macro_use_import(self, ident.span);
1126 self.r.potentially_unused_imports.push(import);
1127 let imported_binding = self.r.import(binding, import);
1128 self.add_macro_use_binding(
1135 struct_span_err!(self.r.session, ident.span, E0469, "imported macro not found")
1140 import_all.is_some() || !single_imports.is_empty()
1143 /// Returns `true` if this attribute list contains `macro_use`.
1144 fn contains_macro_use(&mut self, attrs: &[ast::Attribute]) -> bool {
1146 if self.r.session.check_name(attr, sym::macro_escape) {
1147 let msg = "`#[macro_escape]` is a deprecated synonym for `#[macro_use]`";
1148 let mut err = self.r.session.struct_span_warn(attr.span, msg);
1149 if let ast::AttrStyle::Inner = attr.style {
1150 err.help("try an outer attribute: `#[macro_use]`").emit();
1154 } else if !self.r.session.check_name(attr, sym::macro_use) {
1158 if !attr.is_word() {
1159 self.r.session.span_err(attr.span, "arguments to `macro_use` are not allowed here");
1167 fn visit_invoc(&mut self, id: NodeId) -> ExpnId {
1168 let invoc_id = id.placeholder_to_expn_id();
1169 let old_parent_scope = self.r.invocation_parent_scopes.insert(invoc_id, self.parent_scope);
1170 assert!(old_parent_scope.is_none(), "invocation data is reset for an invocation");
1174 /// Visit invocation in context in which it can emit a named item (possibly `macro_rules`)
1175 /// directly into its parent scope's module.
1176 fn visit_invoc_in_module(&mut self, id: NodeId) -> MacroRulesScopeRef<'a> {
1177 let invoc_id = self.visit_invoc(id);
1178 self.parent_scope.module.unexpanded_invocations.borrow_mut().insert(invoc_id);
1179 self.r.arenas.alloc_macro_rules_scope(MacroRulesScope::Invocation(invoc_id))
1182 fn proc_macro_stub(&self, item: &ast::Item) -> Option<(MacroKind, Ident, Span)> {
1183 if self.r.session.contains_name(&item.attrs, sym::proc_macro) {
1184 return Some((MacroKind::Bang, item.ident, item.span));
1185 } else if self.r.session.contains_name(&item.attrs, sym::proc_macro_attribute) {
1186 return Some((MacroKind::Attr, item.ident, item.span));
1187 } else if let Some(attr) = self.r.session.find_by_name(&item.attrs, sym::proc_macro_derive)
1189 if let Some(nested_meta) = attr.meta_item_list().and_then(|list| list.get(0).cloned()) {
1190 if let Some(ident) = nested_meta.ident() {
1191 return Some((MacroKind::Derive, ident, ident.span));
1198 // Mark the given macro as unused unless its name starts with `_`.
1199 // Macro uses will remove items from this set, and the remaining
1200 // items will be reported as `unused_macros`.
1201 fn insert_unused_macro(
1208 if !ident.as_str().starts_with('_') {
1209 self.r.unused_macros.insert(def_id, (node_id, span));
1213 fn define_macro(&mut self, item: &ast::Item) -> MacroRulesScopeRef<'a> {
1214 let parent_scope = self.parent_scope;
1215 let expansion = parent_scope.expansion;
1216 let def_id = self.r.local_def_id(item.id);
1217 let (ext, ident, span, macro_rules) = match &item.kind {
1218 ItemKind::MacroDef(def) => {
1219 let ext = Lrc::new(self.r.compile_macro(item, self.r.session.edition()));
1220 (ext, item.ident, item.span, def.macro_rules)
1222 ItemKind::Fn(..) => match self.proc_macro_stub(item) {
1223 Some((macro_kind, ident, span)) => {
1224 self.r.proc_macro_stubs.insert(def_id);
1225 (self.r.dummy_ext(macro_kind), ident, span, false)
1227 None => return parent_scope.macro_rules,
1229 _ => unreachable!(),
1232 let res = Res::Def(DefKind::Macro(ext.macro_kind()), def_id.to_def_id());
1233 self.r.macro_map.insert(def_id.to_def_id(), ext);
1234 self.r.local_macro_def_scopes.insert(def_id, parent_scope.module);
1237 let ident = ident.normalize_to_macros_2_0();
1238 self.r.macro_names.insert(ident);
1239 let is_macro_export = self.r.session.contains_name(&item.attrs, sym::macro_export);
1240 let vis = if is_macro_export {
1241 ty::Visibility::Public
1243 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
1245 let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas);
1246 self.r.set_binding_parent_module(binding, parent_scope.module);
1247 self.r.all_macros.insert(ident.name, res);
1248 if is_macro_export {
1249 let module = self.r.graph_root;
1250 self.r.define(module, ident, MacroNS, (res, vis, span, expansion, IsMacroExport));
1252 self.r.check_reserved_macro_name(ident, res);
1253 self.insert_unused_macro(ident, def_id, item.id, span);
1255 self.r.visibilities.insert(def_id, vis);
1256 self.r.arenas.alloc_macro_rules_scope(MacroRulesScope::Binding(
1257 self.r.arenas.alloc_macro_rules_binding(MacroRulesBinding {
1258 parent_macro_rules_scope: parent_scope.macro_rules,
1264 let module = parent_scope.module;
1265 let vis = match item.kind {
1266 // Visibilities must not be resolved non-speculatively twice
1267 // and we already resolved this one as a `fn` item visibility.
1268 ItemKind::Fn(..) => self
1269 .resolve_visibility_speculative(&item.vis, true)
1270 .unwrap_or(ty::Visibility::Public),
1271 _ => self.resolve_visibility(&item.vis),
1273 if vis != ty::Visibility::Public {
1274 self.insert_unused_macro(ident, def_id, item.id, span);
1276 self.r.define(module, ident, MacroNS, (res, vis, span, expansion));
1277 self.r.visibilities.insert(def_id, vis);
1278 self.parent_scope.macro_rules
1283 macro_rules! method {
1284 ($visit:ident: $ty:ty, $invoc:path, $walk:ident) => {
1285 fn $visit(&mut self, node: &'b $ty) {
1286 if let $invoc(..) = node.kind {
1287 self.visit_invoc(node.id);
1289 visit::$walk(self, node);
1295 impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
1296 method!(visit_expr: ast::Expr, ast::ExprKind::MacCall, walk_expr);
1297 method!(visit_pat: ast::Pat, ast::PatKind::MacCall, walk_pat);
1298 method!(visit_ty: ast::Ty, ast::TyKind::MacCall, walk_ty);
1300 fn visit_item(&mut self, item: &'b Item) {
1301 let orig_module_scope = self.parent_scope.module;
1302 self.parent_scope.macro_rules = match item.kind {
1303 ItemKind::MacroDef(..) => {
1304 let macro_rules_scope = self.define_macro(item);
1305 visit::walk_item(self, item);
1308 ItemKind::MacCall(..) => {
1309 let macro_rules_scope = self.visit_invoc_in_module(item.id);
1310 visit::walk_item(self, item);
1314 let orig_macro_rules_scope = self.parent_scope.macro_rules;
1315 self.build_reduced_graph_for_item(item);
1316 visit::walk_item(self, item);
1318 ItemKind::Mod(..) if self.contains_macro_use(&item.attrs) => {
1319 self.parent_scope.macro_rules
1321 _ => orig_macro_rules_scope,
1325 self.parent_scope.module = orig_module_scope;
1328 fn visit_stmt(&mut self, stmt: &'b ast::Stmt) {
1329 if let ast::StmtKind::MacCall(..) = stmt.kind {
1330 self.parent_scope.macro_rules = self.visit_invoc_in_module(stmt.id);
1332 visit::walk_stmt(self, stmt);
1336 fn visit_foreign_item(&mut self, foreign_item: &'b ForeignItem) {
1337 if let ForeignItemKind::MacCall(_) = foreign_item.kind {
1338 self.visit_invoc_in_module(foreign_item.id);
1342 self.build_reduced_graph_for_foreign_item(foreign_item);
1343 visit::walk_foreign_item(self, foreign_item);
1346 fn visit_block(&mut self, block: &'b Block) {
1347 let orig_current_module = self.parent_scope.module;
1348 let orig_current_macro_rules_scope = self.parent_scope.macro_rules;
1349 self.build_reduced_graph_for_block(block);
1350 visit::walk_block(self, block);
1351 self.parent_scope.module = orig_current_module;
1352 self.parent_scope.macro_rules = orig_current_macro_rules_scope;
1355 fn visit_assoc_item(&mut self, item: &'b AssocItem, ctxt: AssocCtxt) {
1356 if let AssocItemKind::MacCall(_) = item.kind {
1358 AssocCtxt::Trait => {
1359 self.visit_invoc_in_module(item.id);
1361 AssocCtxt::Impl => {
1362 self.visit_invoc(item.id);
1368 let local_def_id = self.r.local_def_id(item.id);
1369 let def_id = local_def_id.to_def_id();
1370 let vis = match ctxt {
1371 AssocCtxt::Trait => {
1372 let (def_kind, ns) = match item.kind {
1373 AssocItemKind::Const(..) => (DefKind::AssocConst, ValueNS),
1374 AssocItemKind::Fn(box FnKind(_, ref sig, _, _)) => {
1375 if sig.decl.has_self() {
1376 self.r.has_self.insert(def_id);
1378 (DefKind::AssocFn, ValueNS)
1380 AssocItemKind::TyAlias(..) => (DefKind::AssocTy, TypeNS),
1381 AssocItemKind::MacCall(_) => bug!(), // handled above
1384 let parent = self.parent_scope.module;
1385 let expansion = self.parent_scope.expansion;
1386 let res = Res::Def(def_kind, def_id);
1387 // Trait item visibility is inherited from its trait when not specified explicitly.
1388 let vis = match &item.vis.kind {
1389 ast::VisibilityKind::Inherited => {
1390 self.r.visibilities[&parent.def_id().unwrap().expect_local()]
1392 _ => self.resolve_visibility(&item.vis),
1394 // FIXME: For historical reasons the binding visibility is set to public,
1395 // use actual visibility here instead, using enum variants as an example.
1396 let vis_hack = ty::Visibility::Public;
1397 self.r.define(parent, item.ident, ns, (res, vis_hack, item.span, expansion));
1400 AssocCtxt::Impl => {
1401 // Trait impl item visibility is inherited from its trait when not specified
1402 // explicitly. In that case we cannot determine it here in early resolve,
1403 // so we leave a hole in the visibility table to be filled later.
1404 // Inherent impl item visibility is never inherited from other items.
1405 if matches!(item.vis.kind, ast::VisibilityKind::Inherited)
1409 .contains(&ty::DefIdTree::parent(&*self.r, def_id).unwrap().expect_local())
1413 Some(self.resolve_visibility(&item.vis))
1418 if let Some(vis) = vis {
1419 self.r.visibilities.insert(local_def_id, vis);
1422 visit::walk_assoc_item(self, item, ctxt);
1425 fn visit_attribute(&mut self, attr: &'b ast::Attribute) {
1426 if !attr.is_doc_comment() && attr::is_builtin_attr(attr) {
1429 .push((attr.get_normal_item().path.segments[0].ident, self.parent_scope));
1431 visit::walk_attribute(self, attr);
1434 fn visit_arm(&mut self, arm: &'b ast::Arm) {
1435 if arm.is_placeholder {
1436 self.visit_invoc(arm.id);
1438 visit::walk_arm(self, arm);
1442 fn visit_field(&mut self, f: &'b ast::Field) {
1443 if f.is_placeholder {
1444 self.visit_invoc(f.id);
1446 visit::walk_field(self, f);
1450 fn visit_field_pattern(&mut self, fp: &'b ast::FieldPat) {
1451 if fp.is_placeholder {
1452 self.visit_invoc(fp.id);
1454 visit::walk_field_pattern(self, fp);
1458 fn visit_generic_param(&mut self, param: &'b ast::GenericParam) {
1459 if param.is_placeholder {
1460 self.visit_invoc(param.id);
1462 visit::walk_generic_param(self, param);
1466 fn visit_param(&mut self, p: &'b ast::Param) {
1467 if p.is_placeholder {
1468 self.visit_invoc(p.id);
1470 visit::walk_param(self, p);
1474 fn visit_struct_field(&mut self, sf: &'b ast::StructField) {
1475 if sf.is_placeholder {
1476 self.visit_invoc(sf.id);
1478 let vis = self.resolve_visibility(&sf.vis);
1479 self.r.visibilities.insert(self.r.local_def_id(sf.id), vis);
1480 visit::walk_struct_field(self, sf);
1484 // Constructs the reduced graph for one variant. Variants exist in the
1485 // type and value namespaces.
1486 fn visit_variant(&mut self, variant: &'b ast::Variant) {
1487 if variant.is_placeholder {
1488 self.visit_invoc_in_module(variant.id);
1492 let parent = self.parent_scope.module;
1493 let vis = match variant.vis.kind {
1494 // Variant visibility is inherited from its enum when not specified explicitly.
1495 ast::VisibilityKind::Inherited => {
1496 self.r.visibilities[&parent.def_id().unwrap().expect_local()]
1498 _ => self.resolve_visibility(&variant.vis),
1500 let expn_id = self.parent_scope.expansion;
1501 let ident = variant.ident;
1503 // Define a name in the type namespace.
1504 let def_id = self.r.local_def_id(variant.id);
1505 let res = Res::Def(DefKind::Variant, def_id.to_def_id());
1506 self.r.define(parent, ident, TypeNS, (res, vis, variant.span, expn_id));
1507 self.r.visibilities.insert(def_id, vis);
1509 // If the variant is marked as non_exhaustive then lower the visibility to within the crate.
1510 let ctor_vis = if vis == ty::Visibility::Public
1511 && self.r.session.contains_name(&variant.attrs, sym::non_exhaustive)
1513 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
1518 // Define a constructor name in the value namespace.
1519 // Braced variants, unlike structs, generate unusable names in
1520 // value namespace, they are reserved for possible future use.
1521 // It's ok to use the variant's id as a ctor id since an
1522 // error will be reported on any use of such resolution anyway.
1523 let ctor_node_id = variant.data.ctor_id().unwrap_or(variant.id);
1524 let ctor_def_id = self.r.local_def_id(ctor_node_id);
1525 let ctor_kind = CtorKind::from_ast(&variant.data);
1526 let ctor_res = Res::Def(DefKind::Ctor(CtorOf::Variant, ctor_kind), ctor_def_id.to_def_id());
1527 self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, variant.span, expn_id));
1528 if ctor_def_id != def_id {
1529 self.r.visibilities.insert(ctor_def_id, ctor_vis);
1531 // Record field names for error reporting.
1532 self.insert_field_names_local(ctor_def_id.to_def_id(), &variant.data);
1534 visit::walk_variant(self, variant);