use rustc_ast as ast;
use rustc_ast::visit;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::lang_items::{GenericRequirement, extract};
use rustc_hir::{LangItem, LanguageItems, MethodKind, Target};
use rustc_middle::query::Providers;
use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
use rustc_session::cstore::ExternCrate;
use rustc_span::{Span, kw};
use crate::errors::{
DuplicateLangItem, IncorrectTarget, LangItemOnIncorrectTarget, UnknownLangItem,
};
use crate::weak_lang_items;
pub(crate) enum Duplicate {
Plain,
Crate,
CrateDepends,
}
struct LanguageItemCollector<'ast, 'tcx> {
items: LanguageItems,
tcx: TyCtxt<'tcx>,
resolver: &'ast ResolverAstLowering,
item_spans: FxHashMap<DefId, Span>,
parent_item: Option<&'ast ast::Item>,
}
impl<'ast, 'tcx> LanguageItemCollector<'ast, 'tcx> {
fn new(
tcx: TyCtxt<'tcx>,
resolver: &'ast ResolverAstLowering,
) -> LanguageItemCollector<'ast, 'tcx> {
LanguageItemCollector {
tcx,
resolver,
items: LanguageItems::new(),
item_spans: FxHashMap::default(),
parent_item: None,
}
}
fn check_for_lang(
&mut self,
actual_target: Target,
def_id: LocalDefId,
attrs: &'ast [ast::Attribute],
item_span: Span,
generics: Option<&'ast ast::Generics>,
) {
if let Some((name, attr_span)) = extract(attrs) {
match LangItem::from_name(name) {
Some(lang_item) if actual_target == lang_item.target() => {
self.collect_item_extended(
lang_item,
def_id,
item_span,
attr_span,
generics,
actual_target,
);
}
Some(lang_item) => {
self.tcx.dcx().emit_err(LangItemOnIncorrectTarget {
span: attr_span,
name,
expected_target: lang_item.target(),
actual_target,
});
}
_ => {
self.tcx.dcx().emit_err(UnknownLangItem { span: attr_span, name });
}
}
}
}
fn collect_item(&mut self, lang_item: LangItem, item_def_id: DefId, item_span: Option<Span>) {
if let Some(original_def_id) = self.items.get(lang_item)
&& original_def_id != item_def_id
{
let lang_item_name = lang_item.name();
let crate_name = self.tcx.crate_name(item_def_id.krate);
let mut dependency_of = kw::Empty;
let is_local = item_def_id.is_local();
let path = if is_local {
String::new()
} else {
self.tcx
.crate_extern_paths(item_def_id.krate)
.iter()
.map(|p| p.display().to_string())
.collect::<Vec<_>>()
.join(", ")
};
let first_defined_span = self.item_spans.get(&original_def_id).copied();
let mut orig_crate_name = kw::Empty;
let mut orig_dependency_of = kw::Empty;
let orig_is_local = original_def_id.is_local();
let orig_path = if orig_is_local {
String::new()
} else {
self.tcx
.crate_extern_paths(original_def_id.krate)
.iter()
.map(|p| p.display().to_string())
.collect::<Vec<_>>()
.join(", ")
};
if first_defined_span.is_none() {
orig_crate_name = self.tcx.crate_name(original_def_id.krate);
if let Some(ExternCrate { dependency_of: inner_dependency_of, .. }) =
self.tcx.extern_crate(original_def_id.krate)
{
orig_dependency_of = self.tcx.crate_name(*inner_dependency_of);
}
}
let duplicate = if item_span.is_some() {
Duplicate::Plain
} else {
match self.tcx.extern_crate(item_def_id.krate) {
Some(ExternCrate { dependency_of: inner_dependency_of, .. }) => {
dependency_of = self.tcx.crate_name(*inner_dependency_of);
Duplicate::CrateDepends
}
_ => Duplicate::Crate,
}
};
self.tcx.dcx().emit_fatal(DuplicateLangItem {
local_span: item_span,
lang_item_name,
crate_name,
dependency_of,
is_local,
path,
first_defined_span,
orig_crate_name,
orig_dependency_of,
orig_is_local,
orig_path,
duplicate,
});
} else {
self.items.set(lang_item, item_def_id);
if let Some(item_span) = item_span {
self.item_spans.insert(item_def_id, item_span);
}
}
}
fn collect_item_extended(
&mut self,
lang_item: LangItem,
item_def_id: LocalDefId,
item_span: Span,
attr_span: Span,
generics: Option<&'ast ast::Generics>,
target: Target,
) {
let name = lang_item.name();
if let Some(generics) = generics {
let mut actual_num = generics.params.len();
if target.is_associated_item() {
actual_num += self
.parent_item
.unwrap()
.opt_generics()
.map_or(0, |generics| generics.params.len());
}
let mut at_least = false;
let required = match lang_item.required_generics() {
GenericRequirement::Exact(num) if num != actual_num => Some(num),
GenericRequirement::Minimum(num) if actual_num < num => {
at_least = true;
Some(num)
}
_ => None,
};
if let Some(num) = required {
self.tcx.dcx().emit_err(IncorrectTarget {
span: attr_span,
generics_span: generics.span,
name: name.as_str(),
kind: target.name(),
num,
actual_num,
at_least,
});
return;
}
}
self.collect_item(lang_item, item_def_id.to_def_id(), Some(item_span));
}
}
fn get_lang_items(tcx: TyCtxt<'_>, (): ()) -> LanguageItems {
let resolver = tcx.resolver_for_lowering().borrow();
let (resolver, krate) = &*resolver;
let mut collector = LanguageItemCollector::new(tcx, resolver);
for &cnum in tcx.used_crates(()).iter() {
for &(def_id, lang_item) in tcx.defined_lang_items(cnum).iter() {
collector.collect_item(lang_item, def_id, None);
}
}
visit::Visitor::visit_crate(&mut collector, krate);
weak_lang_items::check_crate(tcx, &mut collector.items, krate);
collector.items
}
impl<'ast, 'tcx> visit::Visitor<'ast> for LanguageItemCollector<'ast, 'tcx> {
fn visit_item(&mut self, i: &'ast ast::Item) {
let target = match &i.kind {
ast::ItemKind::ExternCrate(_) => Target::ExternCrate,
ast::ItemKind::Use(_) => Target::Use,
ast::ItemKind::Static(_) => Target::Static,
ast::ItemKind::Const(_) => Target::Const,
ast::ItemKind::Fn(_) | ast::ItemKind::Delegation(..) => Target::Fn,
ast::ItemKind::Mod(_, _) => Target::Mod,
ast::ItemKind::ForeignMod(_) => Target::ForeignFn,
ast::ItemKind::GlobalAsm(_) => Target::GlobalAsm,
ast::ItemKind::TyAlias(_) => Target::TyAlias,
ast::ItemKind::Enum(_, _) => Target::Enum,
ast::ItemKind::Struct(_, _) => Target::Struct,
ast::ItemKind::Union(_, _) => Target::Union,
ast::ItemKind::Trait(_) => Target::Trait,
ast::ItemKind::TraitAlias(_, _) => Target::TraitAlias,
ast::ItemKind::Impl(_) => Target::Impl,
ast::ItemKind::MacroDef(_) => Target::MacroDef,
ast::ItemKind::MacCall(_) | ast::ItemKind::DelegationMac(_) => {
unreachable!("macros should have been expanded")
}
};
self.check_for_lang(
target,
self.resolver.node_id_to_def_id[&i.id],
&i.attrs,
i.span,
i.opt_generics(),
);
let parent_item = self.parent_item.replace(i);
visit::walk_item(self, i);
self.parent_item = parent_item;
}
fn visit_enum_def(&mut self, enum_definition: &'ast ast::EnumDef) {
for variant in &enum_definition.variants {
self.check_for_lang(
Target::Variant,
self.resolver.node_id_to_def_id[&variant.id],
&variant.attrs,
variant.span,
None,
);
}
visit::walk_enum_def(self, enum_definition);
}
fn visit_assoc_item(&mut self, i: &'ast ast::AssocItem, ctxt: visit::AssocCtxt) {
let (target, generics) = match &i.kind {
ast::AssocItemKind::Fn(..) | ast::AssocItemKind::Delegation(..) => {
let (body, generics) = if let ast::AssocItemKind::Fn(fun) = &i.kind {
(fun.body.is_some(), Some(&fun.generics))
} else {
(true, None)
};
(
match &self.parent_item.unwrap().kind {
ast::ItemKind::Impl(i) => {
if i.of_trait.is_some() {
Target::Method(MethodKind::Trait { body })
} else {
Target::Method(MethodKind::Inherent)
}
}
ast::ItemKind::Trait(_) => Target::Method(MethodKind::Trait { body }),
_ => unreachable!(),
},
generics,
)
}
ast::AssocItemKind::Const(ct) => (Target::AssocConst, Some(&ct.generics)),
ast::AssocItemKind::Type(ty) => (Target::AssocTy, Some(&ty.generics)),
ast::AssocItemKind::MacCall(_) | ast::AssocItemKind::DelegationMac(_) => {
unreachable!("macros should have been expanded")
}
};
self.check_for_lang(
target,
self.resolver.node_id_to_def_id[&i.id],
&i.attrs,
i.span,
generics,
);
visit::walk_assoc_item(self, i, ctxt);
}
}
pub(crate) fn provide(providers: &mut Providers) {
providers.get_lang_items = get_lang_items;
}