rust/compiler/rustc_resolve/src/build_reduced_graph.rs
2022-12-09 14:59:39 +00:00

1526 lines
63 KiB
Rust

//! 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 crate::def_collector::collect_definitions;
use crate::imports::{Import, ImportKind};
use crate::macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
use crate::Namespace::{self, MacroNS, TypeNS, ValueNS};
use crate::{Determinacy, ExternPreludeEntry, Finalize, Module, ModuleKind, ModuleOrUniformRoot};
use crate::{
MacroData, NameBinding, NameBindingKind, ParentScope, PathResult, PerNS, ResolutionError,
};
use crate::{Resolver, ResolverArenas, Segment, ToNameBinding, VisResolutionError};
use rustc_ast::visit::{self, AssocCtxt, Visitor};
use rustc_ast::{self as ast, AssocItem, AssocItemKind, MetaItemKind, StmtKind};
use rustc_ast::{Block, Fn, ForeignItem, ForeignItemKind, Impl, Item, ItemKind, NodeId};
use rustc_attr as attr;
use rustc_data_structures::sync::Lrc;
use rustc_errors::{struct_span_err, Applicability};
use rustc_expand::expand::AstFragment;
use rustc_hir::def::{self, *};
use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
use rustc_metadata::creader::LoadedMacro;
use rustc_middle::bug;
use rustc_middle::metadata::ModChild;
use rustc_middle::ty::{self, DefIdTree};
use rustc_session::cstore::CrateStore;
use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind};
use rustc_span::source_map::respan;
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::Span;
use std::cell::Cell;
use std::ptr;
type Res = def::Res<NodeId>;
impl<'a, Id: Into<DefId>> ToNameBinding<'a>
for (Module<'a>, ty::Visibility<Id>, Span, LocalExpnId)
{
fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
arenas.alloc_name_binding(NameBinding {
kind: NameBindingKind::Module(self.0),
ambiguity: None,
vis: self.1.to_def_id(),
span: self.2,
expansion: self.3,
})
}
}
impl<'a, Id: Into<DefId>> ToNameBinding<'a> for (Res, ty::Visibility<Id>, Span, LocalExpnId) {
fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
arenas.alloc_name_binding(NameBinding {
kind: NameBindingKind::Res(self.0),
ambiguity: None,
vis: self.1.to_def_id(),
span: self.2,
expansion: self.3,
})
}
}
impl<'a> Resolver<'a> {
/// 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<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
where
T: ToNameBinding<'a>,
{
let binding = def.to_name_binding(self.arenas);
let key = self.new_key(ident, ns);
if let Err(old_binding) = self.try_define(parent, key, binding) {
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
/// (<https://github.com/rust-lang/rust/pull/77984#issuecomment-712445508>).
pub fn get_nearest_non_block_module(&mut self, mut def_id: DefId) -> Module<'a> {
loop {
match self.get_module(def_id) {
Some(module) => return module,
None => def_id = self.parent(def_id),
}
}
}
pub fn expect_module(&mut self, def_id: DefId) -> Module<'a> {
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<Module<'a>> {
if let module @ Some(..) = self.module_map.get(&def_id) {
return module.copied();
}
if !def_id.is_local() {
let def_kind = self.cstore().def_kind(def_id);
match def_kind {
DefKind::Mod | DefKind::Enum | DefKind::Trait => {
let def_key = self.cstore().def_key(def_id);
let parent = def_key.parent.map(|index| {
self.get_nearest_non_block_module(DefId { index, krate: def_id.krate })
});
let name = if let Some(cnum) = def_id.as_crate_root() {
self.cstore().crate_name(cnum)
} else {
def_key.disambiguated_data.data.get_opt_name().expect("module without name")
};
Some(self.new_module(
parent,
ModuleKind::Def(def_kind, def_id, name),
self.cstore().module_expansion_untracked(def_id, &self.session),
self.cstore().get_span_untracked(def_id, &self.session),
// FIXME: Account for `#[no_implicit_prelude]` attributes.
parent.map_or(false, |module| module.no_implicit_prelude),
))
}
_ => None,
}
} else {
None
}
}
pub(crate) fn expn_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
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))
.unwrap_or(&self.graph_root),
}
}
pub(crate) fn macro_def_scope(&mut self, def_id: DefId) -> Module<'a> {
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(MacroData { ext: self.non_macro_attr.clone(), macro_rules: false })
}
_ => None,
}
}
pub(crate) fn get_macro_by_def_id(&mut self, def_id: DefId) -> MacroData {
if let Some(macro_data) = self.macro_map.get(&def_id) {
return macro_data.clone();
}
let (ext, macro_rules) = match self.cstore().load_macro_untracked(def_id, &self.session) {
LoadedMacro::MacroDef(item, edition) => (
Lrc::new(self.compile_macro(&item, edition).0),
matches!(item.kind, ItemKind::MacroDef(def) if def.macro_rules),
),
LoadedMacro::ProcMacro(extz) => (Lrc::new(extz), false),
};
let macro_data = MacroData { ext, macro_rules };
self.macro_map.insert(def_id, macro_data.clone());
macro_data
}
pub(crate) fn build_reduced_graph(
&mut self,
fragment: &AstFragment,
parent_scope: ParentScope<'a>,
) -> MacroRulesScopeRef<'a> {
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<'a>) {
for child in
Vec::from_iter(self.cstore().module_children_untracked(module.def_id(), self.session))
{
let parent_scope = ParentScope::module(module, self);
BuildReducedGraphVisitor { r: self, parent_scope }
.build_reduced_graph_for_external_crate_res(child);
}
}
}
struct BuildReducedGraphVisitor<'a, 'b> {
r: &'b mut Resolver<'a>,
parent_scope: ParentScope<'a>,
}
impl<'a> AsMut<Resolver<'a>> for BuildReducedGraphVisitor<'a, '_> {
fn as_mut(&mut self) -> &mut Resolver<'a> {
self.r
}
}
impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
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<ty::Visibility, VisResolutionError<'ast>> {
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.visibilities[&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, .. } => {
// Make `PRIVATE_IN_PUBLIC` lint a hard error.
self.r.has_pub_restricted = true;
// 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.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::<Vec<_>>();
let expected_found_error = |res| {
Err(VisResolutionError::ExpectedFound(
path.span,
Segment::names_to_string(&segments),
res,
))
};
match self.r.resolve_path(
&segments,
Some(TypeNS),
parent_scope,
finalize.then(|| Finalize::new(id, path.span)),
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() {
if res == Res::Err {
Ok(ty::Visibility::Public)
} else {
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_names_local(&mut self, def_id: DefId, vdata: &ast::VariantData) {
let field_names = vdata
.fields()
.iter()
.map(|field| respan(field.span, field.ident.map_or(kw::Empty, |ident| ident.name)))
.collect();
self.r.field_names.insert(def_id, field_names);
}
fn insert_field_names_extern(&mut self, def_id: DefId) {
let field_names =
self.r.cstore().struct_field_names_untracked(def_id, self.r.session).collect();
self.r.field_names.insert(def_id, field_names);
}
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<Segment>,
kind: ImportKind<'a>,
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(Import {
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: Cell::new(Some(vis)),
used: Cell::new(false),
});
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 = this.new_key(target, ns);
let mut resolution = this.resolution(current_module, key).borrow_mut();
resolution.add_single_import(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,
// 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
);
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.rust_2015() => {
Some(seg.ident.span.ctxt())
}
None if is_glob && use_tree.span.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::<Vec<_>>();
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;
self.r.visibilities.insert(self.r.local_def_id(id), vis);
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 `src/test/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
.session
.struct_span_err(item.span, "`$crate` may not be imported")
.emit();
}
}
if ident.name == kw::Crate {
self.r.session.span_err(
ident.span,
"crate root imports need to be explicitly named: \
`use crate as name;`",
);
}
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: self.r.session.contains_name(&item.attrs, sym::prelude_import),
max_vis: Cell::new(None),
id,
};
self.r.visibilities.insert(self.r.local_def_id(id), vis);
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(|&(ref use_tree, _)| {
if let ast::UseTreeKind::Simple(..) = use_tree.kind {
if use_tree.ident().name == kw::SelfLower {
return Some(use_tree.span);
}
}
None
})
.collect::<Vec<_>>();
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, // 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,
// The whole `use` item
item,
ty::Visibility::Restricted(
self.parent_scope.module.nearest_parent_mod().expect_local(),
),
root_span,
);
}
}
}
}
/// Constructs the reduced graph for one item.
fn build_reduced_graph_for_item(&mut self, item: &'b 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 local_def_id = self.r.local_def_id(item.id);
let def_id = local_def_id.to_def_id();
self.r.visibilities.insert(local_def_id, 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,
// 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(DefKind::Mod, def_id, ident.name),
expansion.to_expn_id(),
item.span,
parent.no_implicit_prelude
|| self.r.session.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::Static(_, mt, _) => {
let res = Res::Def(DefKind::Static(mt), def_id);
self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
}
ItemKind::Const(..) => {
let res = Res::Def(DefKind::Const, def_id);
self.r.define(parent, ident, ValueNS, (res, vis, sp, expansion));
}
ItemKind::Fn(..) => {
let res = Res::Def(DefKind::Fn, def_id);
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(..) => {
let res = Res::Def(DefKind::TyAlias, def_id);
self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
}
ItemKind::Enum(_, _) => {
let module = self.r.new_module(
Some(parent),
ModuleKind::Def(DefKind::Enum, 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;
}
ItemKind::TraitAlias(..) => {
let res = Res::Def(DefKind::TraitAlias, def_id);
self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
}
// These items live in both the type and value namespaces.
ItemKind::Struct(ref vdata, _) => {
// Define a name in the type namespace.
let res = Res::Def(DefKind::Struct, def_id);
self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
// Record field names for error reporting.
self.insert_field_names_local(def_id, vdata);
// If this is a tuple or unit struct, define a name
// in the value namespace as well.
if let Some((ctor_kind, ctor_node_id)) = CtorKind::from_ast(vdata) {
// If the structure is marked as non_exhaustive then lower the visibility
// to within the crate.
let mut ctor_vis = if vis.is_public()
&& self.r.session.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) {
ctor_vis = field_vis;
}
ret_fields.push(field_vis.to_def_id());
}
let ctor_def_id = self.r.local_def_id(ctor_node_id);
let ctor_res =
Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id.to_def_id());
self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion));
self.r.visibilities.insert(ctor_def_id, ctor_vis);
self.r
.struct_constructors
.insert(def_id, (ctor_res, ctor_vis.to_def_id(), ret_fields));
}
}
ItemKind::Union(ref vdata, _) => {
let res = Res::Def(DefKind::Union, def_id);
self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
// Record field names for error reporting.
self.insert_field_names_local(def_id, vdata);
}
ItemKind::Trait(..) => {
// Add all the items within to a new module.
let module = self.r.new_module(
Some(parent),
ModuleKind::Def(DefKind::Trait, 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 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(_) => unreachable!(),
}
}
fn build_reduced_graph_for_extern_crate(
&mut self,
orig_name: Option<Symbol>,
item: &Item,
local_def_id: LocalDefId,
vis: ty::Visibility,
parent: Module<'a>,
) {
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
.session
.struct_span_err(item.span, "`extern crate self;` requires renaming")
.span_suggestion(
item.span,
"rename the `self` crate to be able to import it",
"extern crate self as name;",
Applicability::HasPlaceholders,
)
.emit();
return;
} else if orig_name == Some(kw::SelfLower) {
Some(self.r.graph_root)
} else {
let crate_id = self.r.crate_loader().process_extern_crate(item, local_def_id);
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::<LocalDefId>::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(Import {
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: Cell::new(Some(vis)),
used: Cell::new(used),
});
self.r.potentially_unused_imports.push(import);
let imported_binding = self.r.import(binding, import);
if ptr::eq(parent, self.r.graph_root) {
if let Some(entry) = self.r.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
if expansion != LocalExpnId::ROOT
&& orig_name.is_some()
&& entry.extern_crate_item.is_none()
{
let msg = "macro-expanded `extern crate` items cannot \
shadow names passed with `--extern`";
self.r.session.span_err(item.span, msg);
}
}
let entry = self.r.extern_prelude.entry(ident.normalize_to_macros_2_0()).or_insert(
ExternPreludeEntry { extern_crate_item: None, introduced_by_item: true },
);
entry.extern_crate_item = Some(imported_binding);
if orig_name.is_some() {
entry.introduced_by_item = true;
}
}
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 local_def_id = self.r.local_def_id(item.id);
let def_id = local_def_id.to_def_id();
let (def_kind, ns) = match item.kind {
ForeignItemKind::Fn(..) => (DefKind::Fn, ValueNS),
ForeignItemKind::Static(_, mt, _) => (DefKind::Static(mt), ValueNS),
ForeignItemKind::TyAlias(..) => (DefKind::ForeignTy, TypeNS),
ForeignItemKind::MacCall(_) => unreachable!(),
};
let parent = self.parent_scope.module;
let expansion = self.parent_scope.expansion;
let vis = self.resolve_visibility(&item.vis);
let res = Res::Def(def_kind, def_id);
self.r.define(parent, item.ident, ns, (res, vis, item.span, expansion));
self.r.visibilities.insert(local_def_id, 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.
}
}
/// Builds the reduced graph for a single item in an external crate.
fn build_reduced_graph_for_external_crate_res(&mut self, child: ModChild) {
let parent = self.parent_scope.module;
let ModChild { ident, res, vis, span, macro_rules } = child;
let res = res.expect_non_local();
let expansion = self.parent_scope.expansion;
// Record primary definitions.
match res {
Res::Def(DefKind::Mod | DefKind::Enum | DefKind::Trait, def_id) => {
let module = self.r.expect_module(def_id);
self.r.define(parent, ident, TypeNS, (module, vis, span, expansion));
}
Res::Def(
DefKind::Struct
| DefKind::Union
| DefKind::Variant
| DefKind::TyAlias
| DefKind::ForeignTy
| DefKind::OpaqueTy
| DefKind::ImplTraitPlaceholder
| DefKind::TraitAlias
| DefKind::AssocTy,
_,
)
| Res::PrimTy(..)
| Res::ToolMod => self.r.define(parent, ident, TypeNS, (res, vis, span, expansion)),
Res::Def(
DefKind::Fn
| DefKind::AssocFn
| DefKind::Static(_)
| DefKind::Const
| DefKind::AssocConst
| DefKind::Ctor(..),
_,
) => self.r.define(parent, ident, ValueNS, (res, vis, span, expansion)),
Res::Def(DefKind::Macro(..), _) | Res::NonMacroAttr(..) => {
if !macro_rules {
self.r.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::Impl
| DefKind::Generator,
_,
)
| Res::Local(..)
| Res::SelfTyParam { .. }
| Res::SelfTyAlias { .. }
| Res::SelfCtor(..)
| Res::Err => bug!("unexpected resolution: {:?}", res),
}
// Record some extra data for better diagnostics.
let cstore = self.r.cstore();
match res {
Res::Def(DefKind::Struct, def_id) => {
if let Some((ctor_kind, ctor_def_id)) = cstore.ctor_untracked(def_id) {
let ctor_res = Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id);
let ctor_vis = cstore.visibility_untracked(ctor_def_id);
let field_visibilities =
cstore.struct_field_visibilities_untracked(def_id).collect();
self.r
.struct_constructors
.insert(def_id, (ctor_res, ctor_vis, field_visibilities));
}
self.insert_field_names_extern(def_id)
}
Res::Def(DefKind::Union, def_id) => self.insert_field_names_extern(def_id),
Res::Def(DefKind::AssocFn, def_id) => {
if cstore.fn_has_self_parameter_untracked(def_id, self.r.session) {
self.r.has_self.insert(def_id);
}
}
_ => {}
}
}
fn add_macro_use_binding(
&mut self,
name: Symbol,
binding: &'a NameBinding<'a>,
span: Span,
allow_shadowing: bool,
) {
if self.r.macro_use_prelude.insert(name, binding).is_some() && !allow_shadowing {
let msg = format!("`{}` is already in scope", name);
let note =
"macro-expanded `#[macro_use]`s may not shadow existing macros (see RFC 1560)";
self.r.session.struct_span_err(span, &msg).note(note).emit();
}
}
/// Returns `true` if we should consider the underlying `extern crate` to be used.
fn process_macro_use_imports(&mut self, item: &Item, module: Module<'a>) -> 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() {
struct_span_err!(
self.r.session,
item.span,
E0468,
"an `extern crate` loading macros must be at the crate root"
)
.emit();
}
if let ItemKind::ExternCrate(Some(orig_name)) = item.kind {
if orig_name == kw::SelfLower {
self.r
.session
.struct_span_err(
attr.span,
"`#[macro_use]` is not supported on `extern crate self`",
)
.emit();
}
}
let ill_formed = |span| {
struct_span_err!(self.r.session, span, E0466, "bad macro import").emit();
};
match attr.meta() {
Some(meta) => match meta.kind {
MetaItemKind::Word => {
import_all = Some(meta.span);
break;
}
MetaItemKind::List(nested_metas) => {
for nested_meta in nested_metas {
match nested_meta.ident() {
Some(ident) if nested_meta.is_word() => {
single_imports.push(ident)
}
_ => ill_formed(nested_meta.span()),
}
}
}
MetaItemKind::NameValue(..) => ill_formed(meta.span),
},
None => ill_formed(attr.span),
}
}
}
let macro_use_import = |this: &Self, span| {
this.r.arenas.alloc_import(Import {
kind: ImportKind::MacroUse,
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: Cell::new(Some(ty::Visibility::Restricted(CRATE_DEF_ID))),
used: Cell::new(false),
})
};
let allow_shadowing = self.parent_scope.expansion == LocalExpnId::ROOT;
if let Some(span) = import_all {
let import = macro_use_import(self, span);
self.r.potentially_unused_imports.push(import);
module.for_each_child(self, |this, ident, ns, binding| {
if ns == MacroNS {
let imported_binding = this.r.import(binding, import);
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,
);
if let Ok(binding) = result {
let import = macro_use_import(self, ident.span);
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 {
struct_span_err!(self.r.session, ident.span, E0469, "imported macro not found")
.emit();
}
}
}
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 msg = "`#[macro_escape]` is a deprecated synonym for `#[macro_use]`";
let mut err = self.r.session.struct_span_warn(attr.span, msg);
if let ast::AttrStyle::Inner = attr.style {
err.help("try an outer attribute: `#[macro_use]`").emit();
} else {
err.emit();
}
} else if !attr.has_name(sym::macro_use) {
continue;
}
if !attr.is_word() {
self.r.session.span_err(attr.span, "arguments to `macro_use` are not allowed here");
}
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<'a> {
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 self.r.session.contains_name(&item.attrs, sym::proc_macro) {
return Some((MacroKind::Bang, item.ident, item.span));
} else if self.r.session.contains_name(&item.attrs, sym::proc_macro_attribute) {
return Some((MacroKind::Attr, item.ident, item.span));
} else if let Some(attr) = self.r.session.find_by_name(&item.attrs, sym::proc_macro_derive)
{
if let Some(nested_meta) = attr.meta_item_list().and_then(|list| list.get(0).cloned()) {
if let Some(ident) = nested_meta.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,
rule_spans: &[(usize, Span)],
) {
if !ident.as_str().starts_with('_') {
self.r.unused_macros.insert(def_id, (node_id, ident));
for (rule_i, rule_span) in rule_spans.iter() {
self.r.unused_macro_rules.insert((def_id, *rule_i), (ident, *rule_span));
}
}
}
fn define_macro(&mut self, item: &ast::Item) -> MacroRulesScopeRef<'a> {
let parent_scope = self.parent_scope;
let expansion = parent_scope.expansion;
let def_id = self.r.local_def_id(item.id);
let (ext, ident, span, macro_rules, rule_spans) = match &item.kind {
ItemKind::MacroDef(def) => {
let (ext, rule_spans) = self.r.compile_macro(item, self.r.session.edition());
let ext = Lrc::new(ext);
(ext, item.ident, item.span, def.macro_rules, rule_spans)
}
ItemKind::Fn(..) => match self.proc_macro_stub(item) {
Some((macro_kind, ident, span)) => {
self.r.proc_macro_stubs.insert(def_id);
(self.r.dummy_ext(macro_kind), ident, span, false, Vec::new())
}
None => return parent_scope.macro_rules,
},
_ => unreachable!(),
};
let res = Res::Def(DefKind::Macro(ext.macro_kind()), def_id.to_def_id());
self.r.macro_map.insert(def_id.to_def_id(), MacroData { ext, macro_rules });
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 = self.r.session.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);
if is_macro_export {
let import = self.r.arenas.alloc_import(Import {
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: span,
module_path: Vec::new(),
vis: Cell::new(Some(vis)),
used: Cell::new(true),
});
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, &rule_spans);
}
self.r.visibilities.insert(def_id, 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, &rule_spans);
}
self.r.define(module, ident, MacroNS, (res, vis, span, expansion));
self.r.visibilities.insert(def_id, vis);
self.parent_scope.macro_rules
}
}
}
macro_rules! method {
($visit:ident: $ty:ty, $invoc:path, $walk:ident) => {
fn $visit(&mut self, node: &'b $ty) {
if let $invoc(..) = node.kind {
self.visit_invoc(node.id);
} else {
visit::$walk(self, node);
}
}
};
}
impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
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: &'b 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(..) => {
let macro_rules_scope = self.visit_invoc_in_module(item.id);
visit::walk_item(self, item);
macro_rules_scope
}
_ => {
let orig_macro_rules_scope = self.parent_scope.macro_rules;
self.build_reduced_graph_for_item(item);
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: &'b 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: &'b 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_foreign_item(self, foreign_item);
}
fn visit_block(&mut self, block: &'b 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: &'b AssocItem, ctxt: AssocCtxt) {
if let AssocItemKind::MacCall(_) = item.kind {
match ctxt {
AssocCtxt::Trait => {
self.visit_invoc_in_module(item.id);
}
AssocCtxt::Impl => {
self.visit_invoc(item.id);
}
}
return;
}
let vis = self.resolve_visibility(&item.vis);
let local_def_id = self.r.local_def_id(item.id);
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(&ty::DefIdTree::local_parent(&*self.r, 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.visibilities.insert(local_def_id, vis);
}
if ctxt == AssocCtxt::Trait {
let (def_kind, ns) = match item.kind {
AssocItemKind::Const(..) => (DefKind::AssocConst, ValueNS),
AssocItemKind::Fn(box Fn { ref sig, .. }) => {
if sig.decl.has_self() {
self.r.has_self.insert(def_id);
}
(DefKind::AssocFn, ValueNS)
}
AssocItemKind::Type(..) => (DefKind::AssocTy, TypeNS),
AssocItemKind::MacCall(_) => bug!(), // handled above
};
let parent = self.parent_scope.module;
let expansion = self.parent_scope.expansion;
let res = Res::Def(def_kind, def_id);
self.r.define(parent, item.ident, ns, (res, vis, item.span, expansion));
}
visit::walk_assoc_item(self, item, ctxt);
}
fn visit_attribute(&mut self, attr: &'b 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: &'b ast::Arm) {
if arm.is_placeholder {
self.visit_invoc(arm.id);
} else {
visit::walk_arm(self, arm);
}
}
fn visit_expr_field(&mut self, f: &'b 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: &'b 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: &'b ast::GenericParam) {
if param.is_placeholder {
self.visit_invoc(param.id);
} else {
visit::walk_generic_param(self, param);
}
}
fn visit_param(&mut self, p: &'b ast::Param) {
if p.is_placeholder {
self.visit_invoc(p.id);
} else {
visit::walk_param(self, p);
}
}
fn visit_field_def(&mut self, sf: &'b ast::FieldDef) {
if sf.is_placeholder {
self.visit_invoc(sf.id);
} else {
let vis = self.resolve_visibility(&sf.vis);
self.r.visibilities.insert(self.r.local_def_id(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: &'b 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 def_id = self.r.local_def_id(variant.id);
let res = Res::Def(DefKind::Variant, def_id.to_def_id());
let vis = self.resolve_visibility(&variant.vis);
self.r.define(parent, ident, TypeNS, (res, vis, variant.span, expn_id));
self.r.visibilities.insert(def_id, vis);
// If the variant is marked as non_exhaustive then lower the visibility to within the crate.
let ctor_vis = if vis.is_public()
&& self.r.session.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_kind, ctor_node_id)) = CtorKind::from_ast(&variant.data) {
let ctor_def_id = self.r.local_def_id(ctor_node_id);
let ctor_res =
Res::Def(DefKind::Ctor(CtorOf::Variant, ctor_kind), ctor_def_id.to_def_id());
self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, variant.span, expn_id));
self.r.visibilities.insert(ctor_def_id, ctor_vis);
}
// Record field names for error reporting.
self.insert_field_names_local(def_id.to_def_id(), &variant.data);
visit::walk_variant(self, variant);
}
fn visit_crate(&mut self, krate: &'b ast::Crate) {
if krate.is_placeholder {
self.visit_invoc_in_module(krate.id);
} else {
visit::walk_crate(self, krate);
self.contains_macro_use(&krate.attrs);
}
}
}