//! After we obtain a fresh AST fragment from a macro, code in this module helps to integrate //! that fragment into the module structures that are already partially built. //! //! Items from the fragment are placed into modules, //! unexpanded macros in the fragment are visited and registered. //! Imports are also considered items and placed into modules here, but not resolved yet. use std::cell::Cell; use rustc_ast::visit::{self, AssocCtxt, Visitor, WalkItemKind}; use rustc_ast::{ self as ast, AssocItem, AssocItemKind, Block, ForeignItem, ForeignItemKind, Impl, Item, ItemKind, MetaItemKind, NodeId, StmtKind, }; use rustc_attr as attr; use rustc_data_structures::sync::Lrc; use rustc_expand::base::ResolverExpand; use rustc_expand::expand::AstFragment; use rustc_hir::def::{self, *}; use rustc_hir::def_id::{CRATE_DEF_ID, DefId, LocalDefId}; use rustc_metadata::creader::LoadedMacro; use rustc_middle::metadata::ModChild; use rustc_middle::ty::Feed; use rustc_middle::{bug, ty}; use rustc_span::Span; use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind}; use rustc_span::symbol::{Ident, Symbol, kw, sym}; use tracing::debug; use crate::Namespace::{MacroNS, TypeNS, ValueNS}; use crate::def_collector::collect_definitions; use crate::imports::{ImportData, ImportKind}; use crate::macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef}; use crate::{ BindingKey, Determinacy, ExternPreludeEntry, Finalize, MacroData, Module, ModuleKind, ModuleOrUniformRoot, NameBinding, NameBindingData, NameBindingKind, ParentScope, PathResult, ResolutionError, Resolver, ResolverArenas, Segment, ToNameBinding, Used, VisResolutionError, errors, }; type Res = def::Res; impl<'ra, Id: Into> ToNameBinding<'ra> for (Module<'ra>, ty::Visibility, Span, LocalExpnId) { fn to_name_binding(self, arenas: &'ra ResolverArenas<'ra>) -> NameBinding<'ra> { arenas.alloc_name_binding(NameBindingData { kind: NameBindingKind::Module(self.0), ambiguity: None, warn_ambiguity: false, vis: self.1.to_def_id(), span: self.2, expansion: self.3, }) } } impl<'ra, Id: Into> ToNameBinding<'ra> for (Res, ty::Visibility, Span, LocalExpnId) { fn to_name_binding(self, arenas: &'ra ResolverArenas<'ra>) -> NameBinding<'ra> { arenas.alloc_name_binding(NameBindingData { kind: NameBindingKind::Res(self.0), ambiguity: None, warn_ambiguity: false, vis: self.1.to_def_id(), span: self.2, expansion: self.3, }) } } impl<'ra, 'tcx> Resolver<'ra, 'tcx> { /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined; /// otherwise, reports an error. pub(crate) fn define(&mut self, parent: Module<'ra>, ident: Ident, ns: Namespace, def: T) where T: ToNameBinding<'ra>, { let binding = def.to_name_binding(self.arenas); let key = self.new_disambiguated_key(ident, ns); if let Err(old_binding) = self.try_define(parent, key, binding, false) { self.report_conflict(parent, ident, ns, old_binding, binding); } } /// Walks up the tree of definitions starting at `def_id`, /// stopping at the first encountered module. /// Parent block modules for arbitrary def-ids are not recorded for the local crate, /// and are not preserved in metadata for foreign crates, so block modules are never /// returned by this function. /// /// For the local crate ignoring block modules may be incorrect, so use this method with care. /// /// For foreign crates block modules can be ignored without introducing observable differences, /// moreover they has to be ignored right now because they are not kept in metadata. /// Foreign parent modules are used for resolving names used by foreign macros with def-site /// hygiene, therefore block module ignorability relies on macros with def-site hygiene and /// block module parents being unreachable from other crates. /// Reachable macros with block module parents exist due to `#[macro_export] macro_rules!`, /// but they cannot use def-site hygiene, so the assumption holds /// (). pub(crate) fn get_nearest_non_block_module(&mut self, mut def_id: DefId) -> Module<'ra> { loop { match self.get_module(def_id) { Some(module) => return module, None => def_id = self.tcx.parent(def_id), } } } pub(crate) fn expect_module(&mut self, def_id: DefId) -> Module<'ra> { self.get_module(def_id).expect("argument `DefId` is not a module") } /// If `def_id` refers to a module (in resolver's sense, i.e. a module item, crate root, enum, /// or trait), then this function returns that module's resolver representation, otherwise it /// returns `None`. pub(crate) fn get_module(&mut self, def_id: DefId) -> Option> { if let module @ Some(..) = self.module_map.get(&def_id) { return module.copied(); } if !def_id.is_local() { // Query `def_kind` is not used because query system overhead is too expensive here. let def_kind = self.cstore().def_kind_untracked(def_id); if let DefKind::Mod | DefKind::Enum | DefKind::Trait = def_kind { let parent = self .tcx .opt_parent(def_id) .map(|parent_id| self.get_nearest_non_block_module(parent_id)); // Query `expn_that_defined` is not used because // hashing spans in its result is expensive. let expn_id = self.cstore().expn_that_defined_untracked(def_id, self.tcx.sess); return Some(self.new_module( parent, ModuleKind::Def(def_kind, def_id, self.tcx.item_name(def_id)), expn_id, self.def_span(def_id), // FIXME: Account for `#[no_implicit_prelude]` attributes. parent.is_some_and(|module| module.no_implicit_prelude), )); } } None } pub(crate) fn expn_def_scope(&mut self, expn_id: ExpnId) -> Module<'ra> { match expn_id.expn_data().macro_def_id { Some(def_id) => self.macro_def_scope(def_id), None => expn_id .as_local() .and_then(|expn_id| self.ast_transform_scopes.get(&expn_id).copied()) .unwrap_or(self.graph_root), } } pub(crate) fn macro_def_scope(&mut self, def_id: DefId) -> Module<'ra> { if let Some(id) = def_id.as_local() { self.local_macro_def_scopes[&id] } else { self.get_nearest_non_block_module(def_id) } } pub(crate) fn get_macro(&mut self, res: Res) -> Option<&MacroData> { match res { Res::Def(DefKind::Macro(..), def_id) => Some(self.get_macro_by_def_id(def_id)), Res::NonMacroAttr(_) => Some(&self.non_macro_attr), _ => None, } } pub(crate) fn get_macro_by_def_id(&mut self, def_id: DefId) -> &MacroData { if self.macro_map.contains_key(&def_id) { return &self.macro_map[&def_id]; } let loaded_macro = self.cstore().load_macro_untracked(def_id, self.tcx); let macro_data = match loaded_macro { LoadedMacro::MacroDef { def, ident, attrs, span, edition } => { self.compile_macro(&def, ident, &attrs, span, ast::DUMMY_NODE_ID, edition) } LoadedMacro::ProcMacro(ext) => MacroData::new(Lrc::new(ext)), }; self.macro_map.entry(def_id).or_insert(macro_data) } pub(crate) fn build_reduced_graph( &mut self, fragment: &AstFragment, parent_scope: ParentScope<'ra>, ) -> MacroRulesScopeRef<'ra> { collect_definitions(self, fragment, parent_scope.expansion); let mut visitor = BuildReducedGraphVisitor { r: self, parent_scope }; fragment.visit_with(&mut visitor); visitor.parent_scope.macro_rules } pub(crate) fn build_reduced_graph_external(&mut self, module: Module<'ra>) { for child in self.tcx.module_children(module.def_id()) { let parent_scope = ParentScope::module(module, self); self.build_reduced_graph_for_external_crate_res(child, parent_scope) } } /// Builds the reduced graph for a single item in an external crate. fn build_reduced_graph_for_external_crate_res( &mut self, child: &ModChild, parent_scope: ParentScope<'ra>, ) { let parent = parent_scope.module; let ModChild { ident, res, vis, ref reexport_chain } = *child; let span = self.def_span( reexport_chain .first() .and_then(|reexport| reexport.id()) .unwrap_or_else(|| res.def_id()), ); let res = res.expect_non_local(); let expansion = parent_scope.expansion; // Record primary definitions. match res { Res::Def(DefKind::Mod | DefKind::Enum | DefKind::Trait, def_id) => { let module = self.expect_module(def_id); self.define(parent, ident, TypeNS, (module, vis, span, expansion)); } Res::Def( DefKind::Struct | DefKind::Union | DefKind::Variant | DefKind::TyAlias | DefKind::ForeignTy | DefKind::OpaqueTy | DefKind::TraitAlias | DefKind::AssocTy, _, ) | Res::PrimTy(..) | Res::ToolMod => self.define(parent, ident, TypeNS, (res, vis, span, expansion)), Res::Def( DefKind::Fn | DefKind::AssocFn | DefKind::Static { .. } | DefKind::Const | DefKind::AssocConst | DefKind::Ctor(..), _, ) => self.define(parent, ident, ValueNS, (res, vis, span, expansion)), Res::Def(DefKind::Macro(..), _) | Res::NonMacroAttr(..) => { self.define(parent, ident, MacroNS, (res, vis, span, expansion)) } Res::Def( DefKind::TyParam | DefKind::ConstParam | DefKind::ExternCrate | DefKind::Use | DefKind::ForeignMod | DefKind::AnonConst | DefKind::InlineConst | DefKind::Field | DefKind::LifetimeParam | DefKind::GlobalAsm | DefKind::Closure | DefKind::SyntheticCoroutineBody | DefKind::Impl { .. }, _, ) | Res::Local(..) | Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } | Res::SelfCtor(..) | Res::Err => bug!("unexpected resolution: {:?}", res), } } } struct BuildReducedGraphVisitor<'a, 'ra, 'tcx> { r: &'a mut Resolver<'ra, 'tcx>, parent_scope: ParentScope<'ra>, } impl<'ra, 'tcx> AsMut> for BuildReducedGraphVisitor<'_, 'ra, 'tcx> { fn as_mut(&mut self) -> &mut Resolver<'ra, 'tcx> { self.r } } impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> { fn res(&self, def_id: impl Into) -> Res { let def_id = def_id.into(); Res::Def(self.r.tcx.def_kind(def_id), def_id) } fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility { self.try_resolve_visibility(vis, true).unwrap_or_else(|err| { self.r.report_vis_error(err); ty::Visibility::Public }) } fn try_resolve_visibility<'ast>( &mut self, vis: &'ast ast::Visibility, finalize: bool, ) -> Result> { let parent_scope = &self.parent_scope; match vis.kind { ast::VisibilityKind::Public => Ok(ty::Visibility::Public), ast::VisibilityKind::Inherited => { Ok(match self.parent_scope.module.kind { // Any inherited visibility resolved directly inside an enum or trait // (i.e. variants, fields, and trait items) inherits from the visibility // of the enum or trait. ModuleKind::Def(DefKind::Enum | DefKind::Trait, def_id, _) => { self.r.tcx.visibility(def_id).expect_local() } // Otherwise, the visibility is restricted to the nearest parent `mod` item. _ => ty::Visibility::Restricted( self.parent_scope.module.nearest_parent_mod().expect_local(), ), }) } ast::VisibilityKind::Restricted { ref path, id, .. } => { // For visibilities we are not ready to provide correct implementation of "uniform // paths" right now, so on 2018 edition we only allow module-relative paths for now. // On 2015 edition visibilities are resolved as crate-relative by default, // so we are prepending a root segment if necessary. let ident = path.segments.get(0).expect("empty path in visibility").ident; let crate_root = if ident.is_path_segment_keyword() { None } else if ident.span.is_rust_2015() { Some(Segment::from_ident(Ident::new( kw::PathRoot, path.span.shrink_to_lo().with_ctxt(ident.span.ctxt()), ))) } else { return Err(VisResolutionError::Relative2018(ident.span, path)); }; let segments = crate_root .into_iter() .chain(path.segments.iter().map(|seg| seg.into())) .collect::>(); let expected_found_error = |res| { Err(VisResolutionError::ExpectedFound( path.span, Segment::names_to_string(&segments), res, )) }; match self.r.resolve_path( &segments, None, parent_scope, finalize.then(|| Finalize::new(id, path.span)), None, None, ) { PathResult::Module(ModuleOrUniformRoot::Module(module)) => { let res = module.res().expect("visibility resolved to unnamed block"); if finalize { self.r.record_partial_res(id, PartialRes::new(res)); } if module.is_normal() { match res { Res::Err => Ok(ty::Visibility::Public), _ => { let vis = ty::Visibility::Restricted(res.def_id()); if self.r.is_accessible_from(vis, parent_scope.module) { Ok(vis.expect_local()) } else { Err(VisResolutionError::AncestorOnly(path.span)) } } } } else { expected_found_error(res) } } PathResult::Module(..) => Err(VisResolutionError::ModuleOnly(path.span)), PathResult::NonModule(partial_res) => { expected_found_error(partial_res.expect_full_res()) } PathResult::Failed { span, label, suggestion, .. } => { Err(VisResolutionError::FailedToResolve(span, label, suggestion)) } PathResult::Indeterminate => Err(VisResolutionError::Indeterminate(path.span)), } } } } fn insert_field_idents(&mut self, def_id: LocalDefId, fields: &[ast::FieldDef]) { if fields.iter().any(|field| field.is_placeholder) { // The fields are not expanded yet. return; } let fields = fields .iter() .enumerate() .map(|(i, field)| { field.ident.unwrap_or_else(|| Ident::from_str_and_span(&format!("{i}"), field.span)) }) .collect(); self.r.field_names.insert(def_id, fields); } fn insert_field_visibilities_local(&mut self, def_id: DefId, fields: &[ast::FieldDef]) { let field_vis = fields .iter() .map(|field| field.vis.span.until(field.ident.map_or(field.ty.span, |i| i.span))) .collect(); self.r.field_visibility_spans.insert(def_id, field_vis); } fn block_needs_anonymous_module(&mut self, block: &Block) -> bool { // If any statements are items, we need to create an anonymous module block .stmts .iter() .any(|statement| matches!(statement.kind, StmtKind::Item(_) | StmtKind::MacCall(_))) } // Add an import to the current module. fn add_import( &mut self, module_path: Vec, kind: ImportKind<'ra>, span: Span, item: &ast::Item, root_span: Span, root_id: NodeId, vis: ty::Visibility, ) { let current_module = self.parent_scope.module; let import = self.r.arenas.alloc_import(ImportData { kind, parent_scope: self.parent_scope, module_path, imported_module: Cell::new(None), span, use_span: item.span, use_span_with_attributes: item.span_with_attributes(), has_attributes: !item.attrs.is_empty(), root_span, root_id, vis, }); self.r.indeterminate_imports.push(import); match import.kind { // Don't add unresolved underscore imports to modules ImportKind::Single { target: Ident { name: kw::Underscore, .. }, .. } => {} ImportKind::Single { target, type_ns_only, .. } => { self.r.per_ns(|this, ns| { if !type_ns_only || ns == TypeNS { let key = BindingKey::new(target, ns); let mut resolution = this.resolution(current_module, key).borrow_mut(); resolution.single_imports.insert(import); } }); } // We don't add prelude imports to the globs since they only affect lexical scopes, // which are not relevant to import resolution. ImportKind::Glob { is_prelude: true, .. } => {} ImportKind::Glob { .. } => current_module.globs.borrow_mut().push(import), _ => unreachable!(), } } fn build_reduced_graph_for_use_tree( &mut self, // This particular use tree use_tree: &ast::UseTree, id: NodeId, parent_prefix: &[Segment], nested: bool, list_stem: bool, // The whole `use` item item: &Item, vis: ty::Visibility, root_span: Span, ) { debug!( "build_reduced_graph_for_use_tree(parent_prefix={:?}, use_tree={:?}, nested={})", parent_prefix, use_tree, nested ); // Top level use tree reuses the item's id and list stems reuse their parent // use tree's ids, so in both cases their visibilities are already filled. if nested && !list_stem { self.r.feed_visibility(self.r.feed(id), vis); } let mut prefix_iter = parent_prefix .iter() .cloned() .chain(use_tree.prefix.segments.iter().map(|seg| seg.into())) .peekable(); // On 2015 edition imports are resolved as crate-relative by default, // so prefixes are prepended with crate root segment if necessary. // The root is prepended lazily, when the first non-empty prefix or terminating glob // appears, so imports in braced groups can have roots prepended independently. let is_glob = matches!(use_tree.kind, ast::UseTreeKind::Glob); let crate_root = match prefix_iter.peek() { Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.is_rust_2015() => { Some(seg.ident.span.ctxt()) } None if is_glob && use_tree.span.is_rust_2015() => Some(use_tree.span.ctxt()), _ => None, } .map(|ctxt| { Segment::from_ident(Ident::new( kw::PathRoot, use_tree.prefix.span.shrink_to_lo().with_ctxt(ctxt), )) }); let prefix = crate_root.into_iter().chain(prefix_iter).collect::>(); debug!("build_reduced_graph_for_use_tree: prefix={:?}", prefix); let empty_for_self = |prefix: &[Segment]| { prefix.is_empty() || prefix.len() == 1 && prefix[0].ident.name == kw::PathRoot }; match use_tree.kind { ast::UseTreeKind::Simple(rename) => { let mut ident = use_tree.ident(); let mut module_path = prefix; let mut source = module_path.pop().unwrap(); let mut type_ns_only = false; if nested { // Correctly handle `self` if source.ident.name == kw::SelfLower { type_ns_only = true; if empty_for_self(&module_path) { self.r.report_error( use_tree.span, ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix, ); return; } // Replace `use foo::{ self };` with `use foo;` let self_span = source.ident.span; source = module_path.pop().unwrap(); if rename.is_none() { // Keep the span of `self`, but the name of `foo` ident = Ident { name: source.ident.name, span: self_span }; } } } else { // Disallow `self` if source.ident.name == kw::SelfLower { let parent = module_path.last(); let span = match parent { // only `::self` from `use foo::self as bar` Some(seg) => seg.ident.span.shrink_to_hi().to(source.ident.span), None => source.ident.span, }; let span_with_rename = match rename { // only `self as bar` from `use foo::self as bar` Some(rename) => source.ident.span.to(rename.span), None => source.ident.span, }; self.r.report_error(span, ResolutionError::SelfImportsOnlyAllowedWithin { root: parent.is_none(), span_with_rename, }); // Error recovery: replace `use foo::self;` with `use foo;` if let Some(parent) = module_path.pop() { source = parent; if rename.is_none() { ident = source.ident; } } } // Disallow `use $crate;` if source.ident.name == kw::DollarCrate && module_path.is_empty() { let crate_root = self.r.resolve_crate_root(source.ident); let crate_name = match crate_root.kind { ModuleKind::Def(.., name) => name, ModuleKind::Block => unreachable!(), }; // HACK(eddyb) unclear how good this is, but keeping `$crate` // in `source` breaks `tests/ui/imports/import-crate-var.rs`, // while the current crate doesn't have a valid `crate_name`. if crate_name != kw::Empty { // `crate_name` should not be interpreted as relative. module_path.push(Segment::from_ident_and_id( Ident { name: kw::PathRoot, span: source.ident.span }, self.r.next_node_id(), )); source.ident.name = crate_name; } if rename.is_none() { ident.name = crate_name; } self.r.dcx().emit_err(errors::CrateImported { span: item.span }); } } if ident.name == kw::Crate { self.r.dcx().emit_err(errors::UnnamedCrateRootImport { span: ident.span }); } let kind = ImportKind::Single { source: source.ident, target: ident, source_bindings: PerNS { type_ns: Cell::new(Err(Determinacy::Undetermined)), value_ns: Cell::new(Err(Determinacy::Undetermined)), macro_ns: Cell::new(Err(Determinacy::Undetermined)), }, target_bindings: PerNS { type_ns: Cell::new(None), value_ns: Cell::new(None), macro_ns: Cell::new(None), }, type_ns_only, nested, id, }; self.add_import(module_path, kind, use_tree.span, item, root_span, item.id, vis); } ast::UseTreeKind::Glob => { let kind = ImportKind::Glob { is_prelude: attr::contains_name(&item.attrs, sym::prelude_import), max_vis: Cell::new(None), id, }; self.add_import(prefix, kind, use_tree.span, item, root_span, item.id, vis); } ast::UseTreeKind::Nested { ref items, .. } => { // Ensure there is at most one `self` in the list let self_spans = items .iter() .filter_map(|(use_tree, _)| { if let ast::UseTreeKind::Simple(..) = use_tree.kind { if use_tree.ident().name == kw::SelfLower { return Some(use_tree.span); } } None }) .collect::>(); if self_spans.len() > 1 { let mut e = self.r.into_struct_error( self_spans[0], ResolutionError::SelfImportCanOnlyAppearOnceInTheList, ); for other_span in self_spans.iter().skip(1) { e.span_label(*other_span, "another `self` import appears here"); } e.emit(); } for &(ref tree, id) in items { self.build_reduced_graph_for_use_tree( // This particular use tree tree, id, &prefix, true, false, // The whole `use` item item, vis, root_span, ); } // Empty groups `a::b::{}` are turned into synthetic `self` imports // `a::b::c::{self as _}`, so that their prefixes are correctly // resolved and checked for privacy/stability/etc. if items.is_empty() && !empty_for_self(&prefix) { let new_span = prefix[prefix.len() - 1].ident.span; let tree = ast::UseTree { prefix: ast::Path::from_ident(Ident::new(kw::SelfLower, new_span)), kind: ast::UseTreeKind::Simple(Some(Ident::new(kw::Underscore, new_span))), span: use_tree.span, }; self.build_reduced_graph_for_use_tree( // This particular use tree &tree, id, &prefix, true, true, // The whole `use` item item, ty::Visibility::Restricted( self.parent_scope.module.nearest_parent_mod().expect_local(), ), root_span, ); } } } } fn build_reduced_graph_for_struct_variant( &mut self, fields: &[ast::FieldDef], ident: Ident, feed: Feed<'tcx, LocalDefId>, adt_res: Res, adt_vis: ty::Visibility, adt_span: Span, ) { let parent_scope = &self.parent_scope; let parent = parent_scope.module; let expansion = parent_scope.expansion; // Define a name in the type namespace if it is not anonymous. self.r.define(parent, ident, TypeNS, (adt_res, adt_vis, adt_span, expansion)); self.r.feed_visibility(feed, adt_vis); let def_id = feed.key(); // Record field names for error reporting. self.insert_field_idents(def_id, fields); self.insert_field_visibilities_local(def_id.to_def_id(), fields); } /// Constructs the reduced graph for one item. fn build_reduced_graph_for_item(&mut self, item: &'a Item) { let parent_scope = &self.parent_scope; let parent = parent_scope.module; let expansion = parent_scope.expansion; let ident = item.ident; let sp = item.span; let vis = self.resolve_visibility(&item.vis); let feed = self.r.feed(item.id); let local_def_id = feed.key(); let def_id = local_def_id.to_def_id(); let def_kind = self.r.tcx.def_kind(def_id); let res = Res::Def(def_kind, def_id); self.r.feed_visibility(feed, vis); match item.kind { ItemKind::Use(ref use_tree) => { self.build_reduced_graph_for_use_tree( // This particular use tree use_tree, item.id, &[], false, false, // The whole `use` item item, vis, use_tree.span, ); } ItemKind::ExternCrate(orig_name) => { self.build_reduced_graph_for_extern_crate( orig_name, item, local_def_id, vis, parent, ); } ItemKind::Mod(..) => { let module = self.r.new_module( Some(parent), ModuleKind::Def(def_kind, def_id, ident.name), expansion.to_expn_id(), item.span, parent.no_implicit_prelude || attr::contains_name(&item.attrs, sym::no_implicit_prelude), ); self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion)); // Descend into the module. self.parent_scope.module = module; } // These items live in the value namespace. ItemKind::Const(..) | ItemKind::Delegation(..) | ItemKind::Static(..) => { self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion)); } ItemKind::Fn(..) => { self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion)); // Functions introducing procedural macros reserve a slot // in the macro namespace as well (see #52225). self.define_macro(item); } // These items live in the type namespace. ItemKind::TyAlias(..) | ItemKind::TraitAlias(..) => { self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion)); } ItemKind::Enum(_, _) | ItemKind::Trait(..) => { let module = self.r.new_module( Some(parent), ModuleKind::Def(def_kind, def_id, ident.name), expansion.to_expn_id(), item.span, parent.no_implicit_prelude, ); self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion)); self.parent_scope.module = module; } // These items live in both the type and value namespaces. ItemKind::Struct(ref vdata, _) => { self.build_reduced_graph_for_struct_variant( vdata.fields(), ident, feed, res, vis, sp, ); // If this is a tuple or unit struct, define a name // in the value namespace as well. if let Some(ctor_node_id) = vdata.ctor_node_id() { // If the structure is marked as non_exhaustive then lower the visibility // to within the crate. let mut ctor_vis = if vis.is_public() && attr::contains_name(&item.attrs, sym::non_exhaustive) { ty::Visibility::Restricted(CRATE_DEF_ID) } else { vis }; let mut ret_fields = Vec::with_capacity(vdata.fields().len()); for field in vdata.fields() { // NOTE: The field may be an expansion placeholder, but expansion sets // correct visibilities for unnamed field placeholders specifically, so the // constructor visibility should still be determined correctly. let field_vis = self .try_resolve_visibility(&field.vis, false) .unwrap_or(ty::Visibility::Public); if ctor_vis.is_at_least(field_vis, self.r.tcx) { ctor_vis = field_vis; } ret_fields.push(field_vis.to_def_id()); } let feed = self.r.feed(ctor_node_id); let ctor_def_id = feed.key(); let ctor_res = self.res(ctor_def_id); self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion)); self.r.feed_visibility(feed, ctor_vis); // We need the field visibility spans also for the constructor for E0603. self.insert_field_visibilities_local(ctor_def_id.to_def_id(), vdata.fields()); self.r .struct_constructors .insert(local_def_id, (ctor_res, ctor_vis.to_def_id(), ret_fields)); } } ItemKind::Union(ref vdata, _) => { self.build_reduced_graph_for_struct_variant( vdata.fields(), ident, feed, res, vis, sp, ); } // These items do not add names to modules. ItemKind::Impl(box Impl { of_trait: Some(..), .. }) => { self.r.trait_impl_items.insert(local_def_id); } ItemKind::Impl { .. } | ItemKind::ForeignMod(..) | ItemKind::GlobalAsm(..) => {} ItemKind::MacroDef(..) | ItemKind::MacCall(_) | ItemKind::DelegationMac(..) => { unreachable!() } } } fn build_reduced_graph_for_extern_crate( &mut self, orig_name: Option, item: &Item, local_def_id: LocalDefId, vis: ty::Visibility, parent: Module<'ra>, ) { let ident = item.ident; let sp = item.span; let parent_scope = self.parent_scope; let expansion = parent_scope.expansion; let (used, module, binding) = if orig_name.is_none() && ident.name == kw::SelfLower { self.r.dcx().emit_err(errors::ExternCrateSelfRequiresRenaming { span: sp }); return; } else if orig_name == Some(kw::SelfLower) { Some(self.r.graph_root) } else { let tcx = self.r.tcx; let crate_id = self.r.crate_loader(|c| { c.process_extern_crate(item, local_def_id, &tcx.definitions_untracked()) }); crate_id.map(|crate_id| { self.r.extern_crate_map.insert(local_def_id, crate_id); self.r.expect_module(crate_id.as_def_id()) }) } .map(|module| { let used = self.process_macro_use_imports(item, module); let vis = ty::Visibility::::Public; let binding = (module, vis, sp, expansion).to_name_binding(self.r.arenas); (used, Some(ModuleOrUniformRoot::Module(module)), binding) }) .unwrap_or((true, None, self.r.dummy_binding)); let import = self.r.arenas.alloc_import(ImportData { kind: ImportKind::ExternCrate { source: orig_name, target: ident, id: item.id }, root_id: item.id, parent_scope: self.parent_scope, imported_module: Cell::new(module), has_attributes: !item.attrs.is_empty(), use_span_with_attributes: item.span_with_attributes(), use_span: item.span, root_span: item.span, span: item.span, module_path: Vec::new(), vis, }); if used { self.r.import_use_map.insert(import, Used::Other); } self.r.potentially_unused_imports.push(import); let imported_binding = self.r.import(binding, import); if parent == self.r.graph_root { let ident = ident.normalize_to_macros_2_0(); if let Some(entry) = self.r.extern_prelude.get(&ident) { if expansion != LocalExpnId::ROOT && orig_name.is_some() && !entry.is_import() { self.r.dcx().emit_err( errors::MacroExpandedExternCrateCannotShadowExternArguments { span: item.span, }, ); // `return` is intended to discard this binding because it's an // unregistered ambiguity error which would result in a panic // caused by inconsistency `path_res` // more details: https://github.com/rust-lang/rust/pull/111761 return; } } let entry = self .r .extern_prelude .entry(ident) .or_insert(ExternPreludeEntry { binding: None, introduced_by_item: true }); if orig_name.is_some() { entry.introduced_by_item = true; } // Binding from `extern crate` item in source code can replace // a binding from `--extern` on command line here. if !entry.is_import() { entry.binding = Some(imported_binding) } else if ident.name != kw::Underscore { self.r.dcx().span_delayed_bug( item.span, format!("it had been define the external module '{ident}' multiple times"), ); } } self.r.define(parent, ident, TypeNS, imported_binding); } /// Constructs the reduced graph for one foreign item. fn build_reduced_graph_for_foreign_item(&mut self, item: &ForeignItem) { let feed = self.r.feed(item.id); let local_def_id = feed.key(); let def_id = local_def_id.to_def_id(); let ns = match item.kind { ForeignItemKind::Fn(..) => ValueNS, ForeignItemKind::Static(..) => ValueNS, ForeignItemKind::TyAlias(..) => TypeNS, ForeignItemKind::MacCall(..) => unreachable!(), }; let parent = self.parent_scope.module; let expansion = self.parent_scope.expansion; let vis = self.resolve_visibility(&item.vis); self.r.define(parent, item.ident, ns, (self.res(def_id), vis, item.span, expansion)); self.r.feed_visibility(feed, vis); } fn build_reduced_graph_for_block(&mut self, block: &Block) { let parent = self.parent_scope.module; let expansion = self.parent_scope.expansion; if self.block_needs_anonymous_module(block) { let module = self.r.new_module( Some(parent), ModuleKind::Block, expansion.to_expn_id(), block.span, parent.no_implicit_prelude, ); self.r.block_map.insert(block.id, module); self.parent_scope.module = module; // Descend into the block. } } fn add_macro_use_binding( &mut self, name: Symbol, binding: NameBinding<'ra>, span: Span, allow_shadowing: bool, ) { if self.r.macro_use_prelude.insert(name, binding).is_some() && !allow_shadowing { self.r.dcx().emit_err(errors::MacroUseNameAlreadyInUse { span, name }); } } /// Returns `true` if we should consider the underlying `extern crate` to be used. fn process_macro_use_imports(&mut self, item: &Item, module: Module<'ra>) -> bool { let mut import_all = None; let mut single_imports = Vec::new(); for attr in &item.attrs { if attr.has_name(sym::macro_use) { if self.parent_scope.module.parent.is_some() { self.r.dcx().emit_err(errors::ExternCrateLoadingMacroNotAtCrateRoot { span: item.span, }); } if let ItemKind::ExternCrate(Some(orig_name)) = item.kind { if orig_name == kw::SelfLower { self.r.dcx().emit_err(errors::MacroUseExternCrateSelf { span: attr.span }); } } let ill_formed = |span| { self.r.dcx().emit_err(errors::BadMacroImport { span }); }; match attr.meta() { Some(meta) => match meta.kind { MetaItemKind::Word => { import_all = Some(meta.span); break; } MetaItemKind::List(meta_item_inners) => { for meta_item_inner in meta_item_inners { match meta_item_inner.ident() { Some(ident) if meta_item_inner.is_word() => { single_imports.push(ident) } _ => ill_formed(meta_item_inner.span()), } } } MetaItemKind::NameValue(..) => ill_formed(meta.span), }, None => ill_formed(attr.span), } } } let macro_use_import = |this: &Self, span, warn_private| { this.r.arenas.alloc_import(ImportData { kind: ImportKind::MacroUse { warn_private }, root_id: item.id, parent_scope: this.parent_scope, imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))), use_span_with_attributes: item.span_with_attributes(), has_attributes: !item.attrs.is_empty(), use_span: item.span, root_span: span, span, module_path: Vec::new(), vis: ty::Visibility::Restricted(CRATE_DEF_ID), }) }; let allow_shadowing = self.parent_scope.expansion == LocalExpnId::ROOT; if let Some(span) = import_all { let import = macro_use_import(self, span, false); self.r.potentially_unused_imports.push(import); module.for_each_child(self, |this, ident, ns, binding| { if ns == MacroNS { let imported_binding = if this.r.is_accessible_from(binding.vis, this.parent_scope.module) { this.r.import(binding, import) } else if !this.r.is_builtin_macro(binding.res()) && !this.r.macro_use_prelude.contains_key(&ident.name) { // - `!r.is_builtin_macro(res)` excluding the built-in macros such as `Debug` or `Hash`. // - `!r.macro_use_prelude.contains_key(name)` excluding macros defined in other extern // crates such as `std`. // FIXME: This branch should eventually be removed. let import = macro_use_import(this, span, true); this.r.import(binding, import) } else { return; }; this.add_macro_use_binding(ident.name, imported_binding, span, allow_shadowing); } }); } else { for ident in single_imports.iter().cloned() { let result = self.r.maybe_resolve_ident_in_module( ModuleOrUniformRoot::Module(module), ident, MacroNS, &self.parent_scope, None, ); if let Ok(binding) = result { let import = macro_use_import(self, ident.span, false); self.r.potentially_unused_imports.push(import); let imported_binding = self.r.import(binding, import); self.add_macro_use_binding( ident.name, imported_binding, ident.span, allow_shadowing, ); } else { self.r.dcx().emit_err(errors::ImportedMacroNotFound { span: ident.span }); } } } import_all.is_some() || !single_imports.is_empty() } /// Returns `true` if this attribute list contains `macro_use`. fn contains_macro_use(&mut self, attrs: &[ast::Attribute]) -> bool { for attr in attrs { if attr.has_name(sym::macro_escape) { let inner_attribute = matches!(attr.style, ast::AttrStyle::Inner); self.r .dcx() .emit_warn(errors::MacroExternDeprecated { span: attr.span, inner_attribute }); } else if !attr.has_name(sym::macro_use) { continue; } if !attr.is_word() { self.r.dcx().emit_err(errors::ArgumentsMacroUseNotAllowed { span: attr.span }); } return true; } false } fn visit_invoc(&mut self, id: NodeId) -> LocalExpnId { let invoc_id = id.placeholder_to_expn_id(); let old_parent_scope = self.r.invocation_parent_scopes.insert(invoc_id, self.parent_scope); assert!(old_parent_scope.is_none(), "invocation data is reset for an invocation"); invoc_id } /// Visit invocation in context in which it can emit a named item (possibly `macro_rules`) /// directly into its parent scope's module. fn visit_invoc_in_module(&mut self, id: NodeId) -> MacroRulesScopeRef<'ra> { let invoc_id = self.visit_invoc(id); self.parent_scope.module.unexpanded_invocations.borrow_mut().insert(invoc_id); self.r.arenas.alloc_macro_rules_scope(MacroRulesScope::Invocation(invoc_id)) } fn proc_macro_stub(&self, item: &ast::Item) -> Option<(MacroKind, Ident, Span)> { if attr::contains_name(&item.attrs, sym::proc_macro) { return Some((MacroKind::Bang, item.ident, item.span)); } else if attr::contains_name(&item.attrs, sym::proc_macro_attribute) { return Some((MacroKind::Attr, item.ident, item.span)); } else if let Some(attr) = attr::find_by_name(&item.attrs, sym::proc_macro_derive) { if let Some(meta_item_inner) = attr.meta_item_list().and_then(|list| list.get(0).cloned()) { if let Some(ident) = meta_item_inner.ident() { return Some((MacroKind::Derive, ident, ident.span)); } } } None } // Mark the given macro as unused unless its name starts with `_`. // Macro uses will remove items from this set, and the remaining // items will be reported as `unused_macros`. fn insert_unused_macro(&mut self, ident: Ident, def_id: LocalDefId, node_id: NodeId) { if !ident.as_str().starts_with('_') { self.r.unused_macros.insert(def_id, (node_id, ident)); for (rule_i, rule_span) in &self.r.macro_map[&def_id.to_def_id()].rule_spans { self.r .unused_macro_rules .entry(def_id) .or_default() .insert(*rule_i, (ident, *rule_span)); } } } fn define_macro(&mut self, item: &ast::Item) -> MacroRulesScopeRef<'ra> { let parent_scope = self.parent_scope; let expansion = parent_scope.expansion; let feed = self.r.feed(item.id); let def_id = feed.key(); let (res, ident, span, macro_rules) = match &item.kind { ItemKind::MacroDef(def) => (self.res(def_id), item.ident, item.span, def.macro_rules), ItemKind::Fn(..) => match self.proc_macro_stub(item) { Some((macro_kind, ident, span)) => { let res = Res::Def(DefKind::Macro(macro_kind), def_id.to_def_id()); let macro_data = MacroData::new(self.r.dummy_ext(macro_kind)); self.r.macro_map.insert(def_id.to_def_id(), macro_data); self.r.proc_macro_stubs.insert(def_id); (res, ident, span, false) } None => return parent_scope.macro_rules, }, _ => unreachable!(), }; self.r.local_macro_def_scopes.insert(def_id, parent_scope.module); if macro_rules { let ident = ident.normalize_to_macros_2_0(); self.r.macro_names.insert(ident); let is_macro_export = attr::contains_name(&item.attrs, sym::macro_export); let vis = if is_macro_export { ty::Visibility::Public } else { ty::Visibility::Restricted(CRATE_DEF_ID) }; let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas); self.r.set_binding_parent_module(binding, parent_scope.module); self.r.all_macro_rules.insert(ident.name, res); if is_macro_export { let import = self.r.arenas.alloc_import(ImportData { kind: ImportKind::MacroExport, root_id: item.id, parent_scope: self.parent_scope, imported_module: Cell::new(None), has_attributes: false, use_span_with_attributes: span, use_span: span, root_span: span, span, module_path: Vec::new(), vis, }); self.r.import_use_map.insert(import, Used::Other); let import_binding = self.r.import(binding, import); self.r.define(self.r.graph_root, ident, MacroNS, import_binding); } else { self.r.check_reserved_macro_name(ident, res); self.insert_unused_macro(ident, def_id, item.id); } self.r.feed_visibility(feed, vis); let scope = self.r.arenas.alloc_macro_rules_scope(MacroRulesScope::Binding( self.r.arenas.alloc_macro_rules_binding(MacroRulesBinding { parent_macro_rules_scope: parent_scope.macro_rules, binding, ident, }), )); self.r.macro_rules_scopes.insert(def_id, scope); scope } else { let module = parent_scope.module; let vis = match item.kind { // Visibilities must not be resolved non-speculatively twice // and we already resolved this one as a `fn` item visibility. ItemKind::Fn(..) => { self.try_resolve_visibility(&item.vis, false).unwrap_or(ty::Visibility::Public) } _ => self.resolve_visibility(&item.vis), }; if !vis.is_public() { self.insert_unused_macro(ident, def_id, item.id); } self.r.define(module, ident, MacroNS, (res, vis, span, expansion)); self.r.feed_visibility(feed, vis); self.parent_scope.macro_rules } } } macro_rules! method { ($visit:ident: $ty:ty, $invoc:path, $walk:ident) => { fn $visit(&mut self, node: &'a $ty) { if let $invoc(..) = node.kind { self.visit_invoc(node.id); } else { visit::$walk(self, node); } } }; } impl<'a, 'ra, 'tcx> Visitor<'a> for BuildReducedGraphVisitor<'a, 'ra, 'tcx> { method!(visit_expr: ast::Expr, ast::ExprKind::MacCall, walk_expr); method!(visit_pat: ast::Pat, ast::PatKind::MacCall, walk_pat); method!(visit_ty: ast::Ty, ast::TyKind::MacCall, walk_ty); fn visit_item(&mut self, item: &'a Item) { let orig_module_scope = self.parent_scope.module; self.parent_scope.macro_rules = match item.kind { ItemKind::MacroDef(..) => { let macro_rules_scope = self.define_macro(item); visit::walk_item(self, item); macro_rules_scope } ItemKind::MacCall(..) => self.visit_invoc_in_module(item.id), _ => { let orig_macro_rules_scope = self.parent_scope.macro_rules; self.build_reduced_graph_for_item(item); match item.kind { ItemKind::Mod(..) => { // Visit attributes after items for backward compatibility. // This way they can use `macro_rules` defined later. self.visit_vis(&item.vis); self.visit_ident(&item.ident); item.kind.walk(item, AssocCtxt::Trait, self); visit::walk_list!(self, visit_attribute, &item.attrs); } _ => visit::walk_item(self, item), } match item.kind { ItemKind::Mod(..) if self.contains_macro_use(&item.attrs) => { self.parent_scope.macro_rules } _ => orig_macro_rules_scope, } } }; self.parent_scope.module = orig_module_scope; } fn visit_stmt(&mut self, stmt: &'a ast::Stmt) { if let ast::StmtKind::MacCall(..) = stmt.kind { self.parent_scope.macro_rules = self.visit_invoc_in_module(stmt.id); } else { visit::walk_stmt(self, stmt); } } fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) { if let ForeignItemKind::MacCall(_) = foreign_item.kind { self.visit_invoc_in_module(foreign_item.id); return; } self.build_reduced_graph_for_foreign_item(foreign_item); visit::walk_item(self, foreign_item); } fn visit_block(&mut self, block: &'a Block) { let orig_current_module = self.parent_scope.module; let orig_current_macro_rules_scope = self.parent_scope.macro_rules; self.build_reduced_graph_for_block(block); visit::walk_block(self, block); self.parent_scope.module = orig_current_module; self.parent_scope.macro_rules = orig_current_macro_rules_scope; } fn visit_assoc_item(&mut self, item: &'a AssocItem, ctxt: AssocCtxt) { if let AssocItemKind::MacCall(_) = item.kind { match ctxt { AssocCtxt::Trait => { self.visit_invoc_in_module(item.id); } AssocCtxt::Impl => { let invoc_id = item.id.placeholder_to_expn_id(); if !self.r.glob_delegation_invoc_ids.contains(&invoc_id) { self.r .impl_unexpanded_invocations .entry(self.r.invocation_parent(invoc_id)) .or_default() .insert(invoc_id); } self.visit_invoc(item.id); } } return; } let vis = self.resolve_visibility(&item.vis); let feed = self.r.feed(item.id); let local_def_id = feed.key(); let def_id = local_def_id.to_def_id(); if !(ctxt == AssocCtxt::Impl && matches!(item.vis.kind, ast::VisibilityKind::Inherited) && self.r.trait_impl_items.contains(&self.r.tcx.local_parent(local_def_id))) { // Trait impl item visibility is inherited from its trait when not specified // explicitly. In that case we cannot determine it here in early resolve, // so we leave a hole in the visibility table to be filled later. self.r.feed_visibility(feed, vis); } let ns = match item.kind { AssocItemKind::Const(..) | AssocItemKind::Delegation(..) | AssocItemKind::Fn(..) => { ValueNS } AssocItemKind::Type(..) => TypeNS, AssocItemKind::MacCall(_) | AssocItemKind::DelegationMac(..) => bug!(), // handled above }; if ctxt == AssocCtxt::Trait { let parent = self.parent_scope.module; let expansion = self.parent_scope.expansion; self.r.define(parent, item.ident, ns, (self.res(def_id), vis, item.span, expansion)); } else if !matches!(&item.kind, AssocItemKind::Delegation(deleg) if deleg.from_glob) { let impl_def_id = self.r.tcx.local_parent(local_def_id); let key = BindingKey::new(item.ident.normalize_to_macros_2_0(), ns); self.r.impl_binding_keys.entry(impl_def_id).or_default().insert(key); } visit::walk_assoc_item(self, item, ctxt); } fn visit_attribute(&mut self, attr: &'a ast::Attribute) { if !attr.is_doc_comment() && attr::is_builtin_attr(attr) { self.r .builtin_attrs .push((attr.get_normal_item().path.segments[0].ident, self.parent_scope)); } visit::walk_attribute(self, attr); } fn visit_arm(&mut self, arm: &'a ast::Arm) { if arm.is_placeholder { self.visit_invoc(arm.id); } else { visit::walk_arm(self, arm); } } fn visit_expr_field(&mut self, f: &'a ast::ExprField) { if f.is_placeholder { self.visit_invoc(f.id); } else { visit::walk_expr_field(self, f); } } fn visit_pat_field(&mut self, fp: &'a ast::PatField) { if fp.is_placeholder { self.visit_invoc(fp.id); } else { visit::walk_pat_field(self, fp); } } fn visit_generic_param(&mut self, param: &'a ast::GenericParam) { if param.is_placeholder { self.visit_invoc(param.id); } else { visit::walk_generic_param(self, param); } } fn visit_param(&mut self, p: &'a ast::Param) { if p.is_placeholder { self.visit_invoc(p.id); } else { visit::walk_param(self, p); } } fn visit_field_def(&mut self, sf: &'a ast::FieldDef) { if sf.is_placeholder { self.visit_invoc(sf.id); } else { let vis = self.resolve_visibility(&sf.vis); self.r.feed_visibility(self.r.feed(sf.id), vis); visit::walk_field_def(self, sf); } } // Constructs the reduced graph for one variant. Variants exist in the // type and value namespaces. fn visit_variant(&mut self, variant: &'a ast::Variant) { if variant.is_placeholder { self.visit_invoc_in_module(variant.id); return; } let parent = self.parent_scope.module; let expn_id = self.parent_scope.expansion; let ident = variant.ident; // Define a name in the type namespace. let feed = self.r.feed(variant.id); let def_id = feed.key(); let vis = self.resolve_visibility(&variant.vis); self.r.define(parent, ident, TypeNS, (self.res(def_id), vis, variant.span, expn_id)); self.r.feed_visibility(feed, vis); // If the variant is marked as non_exhaustive then lower the visibility to within the crate. let ctor_vis = if vis.is_public() && attr::contains_name(&variant.attrs, sym::non_exhaustive) { ty::Visibility::Restricted(CRATE_DEF_ID) } else { vis }; // Define a constructor name in the value namespace. if let Some(ctor_node_id) = variant.data.ctor_node_id() { let feed = self.r.feed(ctor_node_id); let ctor_def_id = feed.key(); let ctor_res = self.res(ctor_def_id); self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, variant.span, expn_id)); self.r.feed_visibility(feed, ctor_vis); } // Record field names for error reporting. self.insert_field_idents(def_id, variant.data.fields()); self.insert_field_visibilities_local(def_id.to_def_id(), variant.data.fields()); visit::walk_variant(self, variant); } fn visit_crate(&mut self, krate: &'a ast::Crate) { if krate.is_placeholder { self.visit_invoc_in_module(krate.id); } else { // Visit attributes after items for backward compatibility. // This way they can use `macro_rules` defined later. visit::walk_list!(self, visit_item, &krate.items); visit::walk_list!(self, visit_attribute, &krate.attrs); self.contains_macro_use(&krate.attrs); } } }