#![allow(internal_features)]
#![doc(rust_logo)]
#![feature(assert_matches)]
#![feature(box_patterns)]
#![feature(let_chains)]
#![feature(rustdoc_internals)]
#![warn(unreachable_pub)]
use rustc_ast::node_id::NodeMap;
use rustc_ast::ptr::P;
use rustc_ast::{self as ast, *};
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::sorted_map::SortedMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::Lrc;
use rustc_errors::{DiagArgFromDisplay, DiagCtxtHandle, StashKey};
use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE, LocalDefId};
use rustc_hir::{
self as hir, ConstArg, GenericArg, HirId, ItemLocalMap, LangItem, ParamName, TraitCandidate,
};
use rustc_index::{Idx, IndexSlice, IndexVec};
use rustc_macros::extension;
use rustc_middle::span_bug;
use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
use rustc_session::parse::{add_feature_diagnostics, feature_err};
use rustc_span::symbol::{Ident, Symbol, kw, sym};
use rustc_span::{DUMMY_SP, DesugaringKind, Span};
use smallvec::{SmallVec, smallvec};
use thin_vec::ThinVec;
use tracing::{debug, instrument, trace};
use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait};
macro_rules! arena_vec {
($this:expr; $($x:expr),*) => (
$this.arena.alloc_from_iter([$($x),*])
);
}
mod asm;
mod block;
mod delegation;
mod errors;
mod expr;
mod format;
mod index;
mod item;
mod pat;
mod path;
rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
struct LoweringContext<'a, 'hir> {
tcx: TyCtxt<'hir>,
resolver: &'a mut ResolverAstLowering,
arena: &'hir hir::Arena<'hir>,
bodies: Vec<(hir::ItemLocalId, &'hir hir::Body<'hir>)>,
attrs: SortedMap<hir::ItemLocalId, &'hir [Attribute]>,
children: Vec<(LocalDefId, hir::MaybeOwner<'hir>)>,
coroutine_kind: Option<hir::CoroutineKind>,
task_context: Option<HirId>,
current_item: Option<Span>,
catch_scope: Option<HirId>,
loop_scope: Option<HirId>,
is_in_loop_condition: bool,
is_in_trait_impl: bool,
is_in_dyn_type: bool,
current_hir_id_owner: hir::OwnerId,
item_local_id_counter: hir::ItemLocalId,
trait_map: ItemLocalMap<Box<[TraitCandidate]>>,
impl_trait_defs: Vec<hir::GenericParam<'hir>>,
impl_trait_bounds: Vec<hir::WherePredicate<'hir>>,
ident_and_label_to_local_id: NodeMap<hir::ItemLocalId>,
#[cfg(debug_assertions)]
node_id_to_local_id: NodeMap<hir::ItemLocalId>,
allow_try_trait: Lrc<[Symbol]>,
allow_gen_future: Lrc<[Symbol]>,
allow_async_iterator: Lrc<[Symbol]>,
allow_for_await: Lrc<[Symbol]>,
allow_async_fn_traits: Lrc<[Symbol]>,
}
impl<'a, 'hir> LoweringContext<'a, 'hir> {
fn new(tcx: TyCtxt<'hir>, resolver: &'a mut ResolverAstLowering) -> Self {
Self {
tcx,
resolver,
arena: tcx.hir_arena,
bodies: Vec::new(),
attrs: SortedMap::default(),
children: Vec::default(),
current_hir_id_owner: hir::CRATE_OWNER_ID,
item_local_id_counter: hir::ItemLocalId::ZERO,
ident_and_label_to_local_id: Default::default(),
#[cfg(debug_assertions)]
node_id_to_local_id: Default::default(),
trait_map: Default::default(),
catch_scope: None,
loop_scope: None,
is_in_loop_condition: false,
is_in_trait_impl: false,
is_in_dyn_type: false,
coroutine_kind: None,
task_context: None,
current_item: None,
impl_trait_defs: Vec::new(),
impl_trait_bounds: Vec::new(),
allow_try_trait: [sym::try_trait_v2, sym::yeet_desugar_details].into(),
allow_gen_future: if tcx.features().async_fn_track_caller() {
[sym::gen_future, sym::closure_track_caller].into()
} else {
[sym::gen_future].into()
},
allow_for_await: [sym::async_iterator].into(),
allow_async_fn_traits: [sym::async_fn_traits].into(),
allow_async_iterator: [sym::gen_future, sym::async_iterator].into(),
}
}
pub(crate) fn dcx(&self) -> DiagCtxtHandle<'hir> {
self.tcx.dcx()
}
}
#[extension(trait ResolverAstLoweringExt)]
impl ResolverAstLowering {
fn legacy_const_generic_args(&self, expr: &Expr) -> Option<Vec<usize>> {
if let ExprKind::Path(None, path) = &expr.kind {
if path.segments.last().unwrap().args.is_some() {
return None;
}
if let Res::Def(DefKind::Fn, def_id) = self.partial_res_map.get(&expr.id)?.full_res()? {
if def_id.is_local() {
return None;
}
if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
return v.clone();
}
}
}
None
}
fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
self.partial_res_map.get(&id).copied()
}
fn get_import_res(&self, id: NodeId) -> PerNS<Option<Res<NodeId>>> {
self.import_res_map.get(&id).copied().unwrap_or_default()
}
fn get_label_res(&self, id: NodeId) -> Option<NodeId> {
self.label_res_map.get(&id).copied()
}
fn get_lifetime_res(&self, id: NodeId) -> Option<LifetimeRes> {
self.lifetimes_res_map.get(&id).copied()
}
fn extra_lifetime_params(&mut self, id: NodeId) -> Vec<(Ident, NodeId, LifetimeRes)> {
self.extra_lifetime_params_map.get(&id).cloned().unwrap_or_default()
}
}
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
enum ImplTraitContext {
Universal,
OpaqueTy { origin: hir::OpaqueTyOrigin<LocalDefId> },
FeatureGated(ImplTraitPosition, Symbol),
Disallowed(ImplTraitPosition),
}
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
enum ImplTraitPosition {
Path,
Variable,
Trait,
Bound,
Generic,
ExternFnParam,
ClosureParam,
PointerParam,
FnTraitParam,
ExternFnReturn,
ClosureReturn,
PointerReturn,
FnTraitReturn,
GenericDefault,
ConstTy,
StaticTy,
AssocTy,
FieldTy,
Cast,
ImplSelf,
OffsetOf,
}
impl std::fmt::Display for ImplTraitPosition {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let name = match self {
ImplTraitPosition::Path => "paths",
ImplTraitPosition::Variable => "the type of variable bindings",
ImplTraitPosition::Trait => "traits",
ImplTraitPosition::Bound => "bounds",
ImplTraitPosition::Generic => "generics",
ImplTraitPosition::ExternFnParam => "`extern fn` parameters",
ImplTraitPosition::ClosureParam => "closure parameters",
ImplTraitPosition::PointerParam => "`fn` pointer parameters",
ImplTraitPosition::FnTraitParam => "the parameters of `Fn` trait bounds",
ImplTraitPosition::ExternFnReturn => "`extern fn` return types",
ImplTraitPosition::ClosureReturn => "closure return types",
ImplTraitPosition::PointerReturn => "`fn` pointer return types",
ImplTraitPosition::FnTraitReturn => "the return type of `Fn` trait bounds",
ImplTraitPosition::GenericDefault => "generic parameter defaults",
ImplTraitPosition::ConstTy => "const types",
ImplTraitPosition::StaticTy => "static types",
ImplTraitPosition::AssocTy => "associated types",
ImplTraitPosition::FieldTy => "field types",
ImplTraitPosition::Cast => "cast expression types",
ImplTraitPosition::ImplSelf => "impl headers",
ImplTraitPosition::OffsetOf => "`offset_of!` parameters",
};
write!(f, "{name}")
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
enum FnDeclKind {
Fn,
Inherent,
ExternFn,
Closure,
Pointer,
Trait,
Impl,
}
#[derive(Copy, Clone)]
enum AstOwner<'a> {
NonOwner,
Crate(&'a ast::Crate),
Item(&'a ast::Item),
AssocItem(&'a ast::AssocItem, visit::AssocCtxt),
ForeignItem(&'a ast::ForeignItem),
}
fn index_crate<'a>(
node_id_to_def_id: &NodeMap<LocalDefId>,
krate: &'a Crate,
) -> IndexVec<LocalDefId, AstOwner<'a>> {
let mut indexer = Indexer { node_id_to_def_id, index: IndexVec::new() };
*indexer.index.ensure_contains_elem(CRATE_DEF_ID, || AstOwner::NonOwner) =
AstOwner::Crate(krate);
visit::walk_crate(&mut indexer, krate);
return indexer.index;
struct Indexer<'s, 'a> {
node_id_to_def_id: &'s NodeMap<LocalDefId>,
index: IndexVec<LocalDefId, AstOwner<'a>>,
}
impl<'a> visit::Visitor<'a> for Indexer<'_, 'a> {
fn visit_attribute(&mut self, _: &'a Attribute) {
}
fn visit_item(&mut self, item: &'a ast::Item) {
let def_id = self.node_id_to_def_id[&item.id];
*self.index.ensure_contains_elem(def_id, || AstOwner::NonOwner) = AstOwner::Item(item);
visit::walk_item(self, item)
}
fn visit_assoc_item(&mut self, item: &'a ast::AssocItem, ctxt: visit::AssocCtxt) {
let def_id = self.node_id_to_def_id[&item.id];
*self.index.ensure_contains_elem(def_id, || AstOwner::NonOwner) =
AstOwner::AssocItem(item, ctxt);
visit::walk_assoc_item(self, item, ctxt);
}
fn visit_foreign_item(&mut self, item: &'a ast::ForeignItem) {
let def_id = self.node_id_to_def_id[&item.id];
*self.index.ensure_contains_elem(def_id, || AstOwner::NonOwner) =
AstOwner::ForeignItem(item);
visit::walk_item(self, item);
}
}
}
fn compute_hir_hash(
tcx: TyCtxt<'_>,
owners: &IndexSlice<LocalDefId, hir::MaybeOwner<'_>>,
) -> Fingerprint {
let mut hir_body_nodes: Vec<_> = owners
.iter_enumerated()
.filter_map(|(def_id, info)| {
let info = info.as_owner()?;
let def_path_hash = tcx.hir().def_path_hash(def_id);
Some((def_path_hash, info))
})
.collect();
hir_body_nodes.sort_unstable_by_key(|bn| bn.0);
tcx.with_stable_hashing_context(|mut hcx| {
let mut stable_hasher = StableHasher::new();
hir_body_nodes.hash_stable(&mut hcx, &mut stable_hasher);
stable_hasher.finish()
})
}
pub fn lower_to_hir(tcx: TyCtxt<'_>, (): ()) -> hir::Crate<'_> {
let sess = tcx.sess;
tcx.ensure_with_value().output_filenames(());
tcx.ensure_with_value().early_lint_checks(());
tcx.ensure_with_value().debugger_visualizers(LOCAL_CRATE);
tcx.ensure_with_value().get_lang_items(());
let (mut resolver, krate) = tcx.resolver_for_lowering().steal();
let ast_index = index_crate(&resolver.node_id_to_def_id, &krate);
let mut owners = IndexVec::from_fn_n(
|_| hir::MaybeOwner::Phantom,
tcx.definitions_untracked().def_index_count(),
);
for def_id in ast_index.indices() {
item::ItemLowerer {
tcx,
resolver: &mut resolver,
ast_index: &ast_index,
owners: &mut owners,
}
.lower_node(def_id);
}
drop(ast_index);
sess.time("drop_ast", || drop(krate));
let opt_hir_hash =
if tcx.needs_crate_hash() { Some(compute_hir_hash(tcx, &owners)) } else { None };
hir::Crate { owners, opt_hir_hash }
}
#[derive(Copy, Clone, PartialEq, Debug)]
enum ParamMode {
Explicit,
Optional,
}
#[derive(Copy, Clone, Debug)]
enum AllowReturnTypeNotation {
Yes,
No,
}
enum GenericArgsMode {
ParenSugar,
ReturnTypeNotation,
Err,
Silence,
}
impl<'a, 'hir> LoweringContext<'a, 'hir> {
fn create_def(
&mut self,
parent: LocalDefId,
node_id: ast::NodeId,
name: Symbol,
def_kind: DefKind,
span: Span,
) -> LocalDefId {
debug_assert_ne!(node_id, ast::DUMMY_NODE_ID);
assert!(
self.opt_local_def_id(node_id).is_none(),
"adding a def'n for node-id {:?} and def kind {:?} but a previous def'n exists: {:?}",
node_id,
def_kind,
self.tcx.hir().def_key(self.local_def_id(node_id)),
);
let def_id = self.tcx.at(span).create_def(parent, name, def_kind).def_id();
debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
self.resolver.node_id_to_def_id.insert(node_id, def_id);
def_id
}
fn next_node_id(&mut self) -> NodeId {
let start = self.resolver.next_node_id;
let next = start.as_u32().checked_add(1).expect("input too large; ran out of NodeIds");
self.resolver.next_node_id = ast::NodeId::from_u32(next);
start
}
fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
self.resolver.node_id_to_def_id.get(&node).copied()
}
fn local_def_id(&self, node: NodeId) -> LocalDefId {
self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{node:?}`"))
}
#[instrument(level = "debug", skip(self, f))]
fn with_hir_id_owner(
&mut self,
owner: NodeId,
f: impl FnOnce(&mut Self) -> hir::OwnerNode<'hir>,
) {
let def_id = self.local_def_id(owner);
let current_attrs = std::mem::take(&mut self.attrs);
let current_bodies = std::mem::take(&mut self.bodies);
let current_ident_and_label_to_local_id =
std::mem::take(&mut self.ident_and_label_to_local_id);
#[cfg(debug_assertions)]
let current_node_id_to_local_id = std::mem::take(&mut self.node_id_to_local_id);
let current_trait_map = std::mem::take(&mut self.trait_map);
let current_owner =
std::mem::replace(&mut self.current_hir_id_owner, hir::OwnerId { def_id });
let current_local_counter =
std::mem::replace(&mut self.item_local_id_counter, hir::ItemLocalId::new(1));
let current_impl_trait_defs = std::mem::take(&mut self.impl_trait_defs);
let current_impl_trait_bounds = std::mem::take(&mut self.impl_trait_bounds);
#[cfg(debug_assertions)]
{
let _old = self.node_id_to_local_id.insert(owner, hir::ItemLocalId::ZERO);
debug_assert_eq!(_old, None);
}
let item = f(self);
debug_assert_eq!(def_id, item.def_id().def_id);
debug_assert!(self.impl_trait_defs.is_empty());
debug_assert!(self.impl_trait_bounds.is_empty());
let info = self.make_owner_info(item);
self.attrs = current_attrs;
self.bodies = current_bodies;
self.ident_and_label_to_local_id = current_ident_and_label_to_local_id;
#[cfg(debug_assertions)]
{
self.node_id_to_local_id = current_node_id_to_local_id;
}
self.trait_map = current_trait_map;
self.current_hir_id_owner = current_owner;
self.item_local_id_counter = current_local_counter;
self.impl_trait_defs = current_impl_trait_defs;
self.impl_trait_bounds = current_impl_trait_bounds;
debug_assert!(!self.children.iter().any(|(id, _)| id == &def_id));
self.children.push((def_id, hir::MaybeOwner::Owner(info)));
}
fn make_owner_info(&mut self, node: hir::OwnerNode<'hir>) -> &'hir hir::OwnerInfo<'hir> {
let attrs = std::mem::take(&mut self.attrs);
let mut bodies = std::mem::take(&mut self.bodies);
let trait_map = std::mem::take(&mut self.trait_map);
#[cfg(debug_assertions)]
for (id, attrs) in attrs.iter() {
if attrs.is_empty() {
panic!("Stored empty attributes for {:?}", id);
}
}
bodies.sort_by_key(|(k, _)| *k);
let bodies = SortedMap::from_presorted_elements(bodies);
let (opt_hash_including_bodies, attrs_hash) =
self.tcx.hash_owner_nodes(node, &bodies, &attrs);
let num_nodes = self.item_local_id_counter.as_usize();
let (nodes, parenting) = index::index_hir(self.tcx, node, &bodies, num_nodes);
let nodes = hir::OwnerNodes { opt_hash_including_bodies, nodes, bodies };
let attrs = hir::AttributeMap { map: attrs, opt_hash: attrs_hash };
self.arena.alloc(hir::OwnerInfo { nodes, parenting, attrs, trait_map })
}
#[instrument(level = "debug", skip(self), ret)]
fn lower_node_id(&mut self, ast_node_id: NodeId) -> HirId {
assert_ne!(ast_node_id, DUMMY_NODE_ID);
let owner = self.current_hir_id_owner;
let local_id = self.item_local_id_counter;
assert_ne!(local_id, hir::ItemLocalId::ZERO);
self.item_local_id_counter.increment_by(1);
let hir_id = HirId { owner, local_id };
if let Some(def_id) = self.opt_local_def_id(ast_node_id) {
self.children.push((def_id, hir::MaybeOwner::NonOwner(hir_id)));
}
if let Some(traits) = self.resolver.trait_map.remove(&ast_node_id) {
self.trait_map.insert(hir_id.local_id, traits.into_boxed_slice());
}
#[cfg(debug_assertions)]
{
let old = self.node_id_to_local_id.insert(ast_node_id, local_id);
assert_eq!(old, None);
}
hir_id
}
#[instrument(level = "debug", skip(self), ret)]
fn next_id(&mut self) -> HirId {
let owner = self.current_hir_id_owner;
let local_id = self.item_local_id_counter;
assert_ne!(local_id, hir::ItemLocalId::ZERO);
self.item_local_id_counter.increment_by(1);
HirId { owner, local_id }
}
#[instrument(level = "trace", skip(self))]
fn lower_res(&mut self, res: Res<NodeId>) -> Res {
let res: Result<Res, ()> = res.apply_id(|id| {
let owner = self.current_hir_id_owner;
let local_id = self.ident_and_label_to_local_id.get(&id).copied().ok_or(())?;
Ok(HirId { owner, local_id })
});
trace!(?res);
res.unwrap_or(Res::Err)
}
fn expect_full_res(&mut self, id: NodeId) -> Res<NodeId> {
self.resolver.get_partial_res(id).map_or(Res::Err, |pr| pr.expect_full_res())
}
fn lower_import_res(&mut self, id: NodeId, span: Span) -> SmallVec<[Res; 3]> {
let res = self.resolver.get_import_res(id).present_items();
let res: SmallVec<_> = res.map(|res| self.lower_res(res)).collect();
if res.is_empty() {
self.dcx().span_delayed_bug(span, "no resolution for an import");
return smallvec![Res::Err];
}
res
}
fn make_lang_item_qpath(
&mut self,
lang_item: hir::LangItem,
span: Span,
args: Option<&'hir hir::GenericArgs<'hir>>,
) -> hir::QPath<'hir> {
hir::QPath::Resolved(None, self.make_lang_item_path(lang_item, span, args))
}
fn make_lang_item_path(
&mut self,
lang_item: hir::LangItem,
span: Span,
args: Option<&'hir hir::GenericArgs<'hir>>,
) -> &'hir hir::Path<'hir> {
let def_id = self.tcx.require_lang_item(lang_item, Some(span));
let def_kind = self.tcx.def_kind(def_id);
let res = Res::Def(def_kind, def_id);
self.arena.alloc(hir::Path {
span,
res,
segments: self.arena.alloc_from_iter([hir::PathSegment {
ident: Ident::new(lang_item.name(), span),
hir_id: self.next_id(),
res,
args,
infer_args: args.is_none(),
}]),
})
}
fn mark_span_with_reason(
&self,
reason: DesugaringKind,
span: Span,
allow_internal_unstable: Option<Lrc<[Symbol]>>,
) -> Span {
self.tcx.with_stable_hashing_context(|hcx| {
span.mark_with_reason(allow_internal_unstable, reason, span.edition(), hcx)
})
}
fn lower_span(&self, span: Span) -> Span {
if self.tcx.sess.opts.incremental.is_some() {
span.with_parent(Some(self.current_hir_id_owner.def_id))
} else {
span
}
}
fn lower_ident(&self, ident: Ident) -> Ident {
Ident::new(ident.name, self.lower_span(ident.span))
}
#[instrument(level = "debug", skip(self))]
fn lifetime_res_to_generic_param(
&mut self,
ident: Ident,
node_id: NodeId,
res: LifetimeRes,
source: hir::GenericParamSource,
) -> Option<hir::GenericParam<'hir>> {
let (name, kind) = match res {
LifetimeRes::Param { .. } => {
(hir::ParamName::Plain(ident), hir::LifetimeParamKind::Explicit)
}
LifetimeRes::Fresh { param, kind, .. } => {
let _def_id = self.create_def(
self.current_hir_id_owner.def_id,
param,
kw::UnderscoreLifetime,
DefKind::LifetimeParam,
ident.span,
);
debug!(?_def_id);
(hir::ParamName::Fresh, hir::LifetimeParamKind::Elided(kind))
}
LifetimeRes::Static { .. } | LifetimeRes::Error => return None,
res => panic!(
"Unexpected lifetime resolution {:?} for {:?} at {:?}",
res, ident, ident.span
),
};
let hir_id = self.lower_node_id(node_id);
let def_id = self.local_def_id(node_id);
Some(hir::GenericParam {
hir_id,
def_id,
name,
span: self.lower_span(ident.span),
pure_wrt_drop: false,
kind: hir::GenericParamKind::Lifetime { kind },
colon_span: None,
source,
})
}
#[instrument(level = "debug", skip(self))]
#[inline]
fn lower_lifetime_binder(
&mut self,
binder: NodeId,
generic_params: &[GenericParam],
) -> &'hir [hir::GenericParam<'hir>] {
let mut generic_params: Vec<_> = self
.lower_generic_params_mut(generic_params, hir::GenericParamSource::Binder)
.collect();
let extra_lifetimes = self.resolver.extra_lifetime_params(binder);
debug!(?extra_lifetimes);
generic_params.extend(extra_lifetimes.into_iter().filter_map(|(ident, node_id, res)| {
self.lifetime_res_to_generic_param(ident, node_id, res, hir::GenericParamSource::Binder)
}));
let generic_params = self.arena.alloc_from_iter(generic_params);
debug!(?generic_params);
generic_params
}
fn with_dyn_type_scope<T>(&mut self, in_scope: bool, f: impl FnOnce(&mut Self) -> T) -> T {
let was_in_dyn_type = self.is_in_dyn_type;
self.is_in_dyn_type = in_scope;
let result = f(self);
self.is_in_dyn_type = was_in_dyn_type;
result
}
fn with_new_scopes<T>(&mut self, scope_span: Span, f: impl FnOnce(&mut Self) -> T) -> T {
let current_item = self.current_item;
self.current_item = Some(scope_span);
let was_in_loop_condition = self.is_in_loop_condition;
self.is_in_loop_condition = false;
let catch_scope = self.catch_scope.take();
let loop_scope = self.loop_scope.take();
let ret = f(self);
self.catch_scope = catch_scope;
self.loop_scope = loop_scope;
self.is_in_loop_condition = was_in_loop_condition;
self.current_item = current_item;
ret
}
fn lower_attrs(&mut self, id: HirId, attrs: &[Attribute]) -> &'hir [Attribute] {
if attrs.is_empty() {
&[]
} else {
debug_assert_eq!(id.owner, self.current_hir_id_owner);
let ret = self.arena.alloc_from_iter(attrs.iter().map(|a| self.lower_attr(a)));
debug_assert!(!ret.is_empty());
self.attrs.insert(id.local_id, ret);
ret
}
}
fn lower_attr(&self, attr: &Attribute) -> Attribute {
let kind = match attr.kind {
AttrKind::Normal(ref normal) => AttrKind::Normal(P(NormalAttr {
item: AttrItem {
unsafety: normal.item.unsafety,
path: normal.item.path.clone(),
args: self.lower_attr_args(&normal.item.args),
tokens: None,
},
tokens: None,
})),
AttrKind::DocComment(comment_kind, data) => AttrKind::DocComment(comment_kind, data),
};
Attribute { kind, id: attr.id, style: attr.style, span: self.lower_span(attr.span) }
}
fn alias_attrs(&mut self, id: HirId, target_id: HirId) {
debug_assert_eq!(id.owner, self.current_hir_id_owner);
debug_assert_eq!(target_id.owner, self.current_hir_id_owner);
if let Some(&a) = self.attrs.get(&target_id.local_id) {
debug_assert!(!a.is_empty());
self.attrs.insert(id.local_id, a);
}
}
fn lower_attr_args(&self, args: &AttrArgs) -> AttrArgs {
match args {
AttrArgs::Empty => AttrArgs::Empty,
AttrArgs::Delimited(args) => AttrArgs::Delimited(self.lower_delim_args(args)),
&AttrArgs::Eq { eq_span, ref value } => {
let expr = value.unwrap_ast();
let lit = if let ExprKind::Lit(token_lit) = expr.kind
&& let Ok(lit) = MetaItemLit::from_token_lit(token_lit, expr.span)
{
lit
} else {
let guar = self.dcx().has_errors().unwrap();
MetaItemLit {
symbol: kw::Empty,
suffix: None,
kind: LitKind::Err(guar),
span: DUMMY_SP,
}
};
AttrArgs::Eq { eq_span, value: AttrArgsEq::Hir(lit) }
}
}
}
fn lower_delim_args(&self, args: &DelimArgs) -> DelimArgs {
DelimArgs { dspan: args.dspan, delim: args.delim, tokens: args.tokens.flattened() }
}
#[instrument(level = "debug", skip_all)]
fn lower_assoc_item_constraint(
&mut self,
constraint: &AssocItemConstraint,
itctx: ImplTraitContext,
) -> hir::AssocItemConstraint<'hir> {
debug!(?constraint, ?itctx);
let gen_args = if let Some(gen_args) = &constraint.gen_args {
let gen_args_ctor = match gen_args {
GenericArgs::AngleBracketed(data) => {
self.lower_angle_bracketed_parameter_data(data, ParamMode::Explicit, itctx).0
}
GenericArgs::Parenthesized(data) => {
if let Some(first_char) = constraint.ident.as_str().chars().next()
&& first_char.is_ascii_lowercase()
{
let mut err = if !data.inputs.is_empty() {
self.dcx().create_err(errors::BadReturnTypeNotation::Inputs {
span: data.inputs_span,
})
} else if let FnRetTy::Ty(ty) = &data.output {
self.dcx().create_err(errors::BadReturnTypeNotation::Output {
span: data.inputs_span.shrink_to_hi().to(ty.span),
})
} else {
self.dcx().create_err(errors::BadReturnTypeNotation::NeedsDots {
span: data.inputs_span,
})
};
if !self.tcx.features().return_type_notation()
&& self.tcx.sess.is_nightly_build()
{
add_feature_diagnostics(
&mut err,
&self.tcx.sess,
sym::return_type_notation,
);
}
err.emit();
GenericArgsCtor {
args: Default::default(),
constraints: &[],
parenthesized: hir::GenericArgsParentheses::ReturnTypeNotation,
span: data.span,
}
} else {
self.emit_bad_parenthesized_trait_in_assoc_ty(data);
self.lower_angle_bracketed_parameter_data(
&data.as_angle_bracketed_args(),
ParamMode::Explicit,
itctx,
)
.0
}
}
GenericArgs::ParenthesizedElided(span) => GenericArgsCtor {
args: Default::default(),
constraints: &[],
parenthesized: hir::GenericArgsParentheses::ReturnTypeNotation,
span: *span,
},
};
gen_args_ctor.into_generic_args(self)
} else {
self.arena.alloc(hir::GenericArgs::none())
};
let kind = match &constraint.kind {
AssocItemConstraintKind::Equality { term } => {
let term = match term {
Term::Ty(ty) => self.lower_ty(ty, itctx).into(),
Term::Const(c) => self.lower_anon_const_to_const_arg(c).into(),
};
hir::AssocItemConstraintKind::Equality { term }
}
AssocItemConstraintKind::Bound { bounds } => {
if self.is_in_dyn_type {
let suggestion = match itctx {
ImplTraitContext::OpaqueTy { .. } | ImplTraitContext::Universal => {
let bound_end_span = constraint
.gen_args
.as_ref()
.map_or(constraint.ident.span, |args| args.span());
if bound_end_span.eq_ctxt(constraint.span) {
Some(self.tcx.sess.source_map().next_point(bound_end_span))
} else {
None
}
}
_ => None,
};
let guar = self.dcx().emit_err(errors::MisplacedAssocTyBinding {
span: constraint.span,
suggestion,
});
let err_ty =
&*self.arena.alloc(self.ty(constraint.span, hir::TyKind::Err(guar)));
hir::AssocItemConstraintKind::Equality { term: err_ty.into() }
} else {
let bounds = self.lower_param_bounds(bounds, itctx);
hir::AssocItemConstraintKind::Bound { bounds }
}
}
};
hir::AssocItemConstraint {
hir_id: self.lower_node_id(constraint.id),
ident: self.lower_ident(constraint.ident),
gen_args,
kind,
span: self.lower_span(constraint.span),
}
}
fn emit_bad_parenthesized_trait_in_assoc_ty(&self, data: &ParenthesizedArgs) {
let sub = if data.inputs.is_empty() {
let parentheses_span =
data.inputs_span.shrink_to_lo().to(data.inputs_span.shrink_to_hi());
AssocTyParenthesesSub::Empty { parentheses_span }
}
else {
let open_param = data.inputs_span.shrink_to_lo().to(data
.inputs
.first()
.unwrap()
.span
.shrink_to_lo());
let close_param =
data.inputs.last().unwrap().span.shrink_to_hi().to(data.inputs_span.shrink_to_hi());
AssocTyParenthesesSub::NotEmpty { open_param, close_param }
};
self.dcx().emit_err(AssocTyParentheses { span: data.span, sub });
}
#[instrument(level = "debug", skip(self))]
fn lower_generic_arg(
&mut self,
arg: &ast::GenericArg,
itctx: ImplTraitContext,
) -> hir::GenericArg<'hir> {
match arg {
ast::GenericArg::Lifetime(lt) => GenericArg::Lifetime(self.lower_lifetime(lt)),
ast::GenericArg::Type(ty) => {
match &ty.kind {
TyKind::Infer if self.tcx.features().generic_arg_infer() => {
return GenericArg::Infer(hir::InferArg {
hir_id: self.lower_node_id(ty.id),
span: self.lower_span(ty.span),
});
}
TyKind::Path(None, path) => {
if let Some(res) = self
.resolver
.get_partial_res(ty.id)
.and_then(|partial_res| partial_res.full_res())
{
if !res.matches_ns(Namespace::TypeNS)
&& path.is_potential_trivial_const_arg()
{
debug!(
"lower_generic_arg: Lowering type argument as const argument: {:?}",
ty,
);
let ct =
self.lower_const_path_to_const_arg(path, res, ty.id, ty.span);
return GenericArg::Const(ct);
}
}
}
_ => {}
}
GenericArg::Type(self.lower_ty(ty, itctx))
}
ast::GenericArg::Const(ct) => GenericArg::Const(self.lower_anon_const_to_const_arg(ct)),
}
}
#[instrument(level = "debug", skip(self))]
fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext) -> &'hir hir::Ty<'hir> {
self.arena.alloc(self.lower_ty_direct(t, itctx))
}
fn lower_path_ty(
&mut self,
t: &Ty,
qself: &Option<ptr::P<QSelf>>,
path: &Path,
param_mode: ParamMode,
itctx: ImplTraitContext,
) -> hir::Ty<'hir> {
if qself.is_none()
&& let Some(partial_res) = self.resolver.get_partial_res(t.id)
&& let Some(Res::Def(DefKind::Trait | DefKind::TraitAlias, _)) = partial_res.full_res()
{
let (bounds, lifetime_bound) = self.with_dyn_type_scope(true, |this| {
let bound = this.lower_poly_trait_ref(
&PolyTraitRef {
bound_generic_params: ThinVec::new(),
modifiers: TraitBoundModifiers::NONE,
trait_ref: TraitRef { path: path.clone(), ref_id: t.id },
span: t.span,
},
itctx,
);
let bounds = this.arena.alloc_from_iter([bound]);
let lifetime_bound = this.elided_dyn_bound(t.span);
(bounds, lifetime_bound)
});
let kind = hir::TyKind::TraitObject(bounds, lifetime_bound, TraitObjectSyntax::None);
return hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.next_id() };
}
let id = self.lower_node_id(t.id);
let qpath = self.lower_qpath(
t.id,
qself,
path,
param_mode,
AllowReturnTypeNotation::Yes,
itctx,
None,
);
self.ty_path(id, t.span, qpath)
}
fn ty(&mut self, span: Span, kind: hir::TyKind<'hir>) -> hir::Ty<'hir> {
hir::Ty { hir_id: self.next_id(), kind, span: self.lower_span(span) }
}
fn ty_tup(&mut self, span: Span, tys: &'hir [hir::Ty<'hir>]) -> hir::Ty<'hir> {
self.ty(span, hir::TyKind::Tup(tys))
}
fn lower_ty_direct(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir> {
let kind = match &t.kind {
TyKind::Infer => hir::TyKind::Infer,
TyKind::Err(guar) => hir::TyKind::Err(*guar),
TyKind::Slice(ty) => hir::TyKind::Slice(self.lower_ty(ty, itctx)),
TyKind::Ptr(mt) => hir::TyKind::Ptr(self.lower_mt(mt, itctx)),
TyKind::Ref(region, mt) => {
let region = region.unwrap_or_else(|| {
let id = if let Some(LifetimeRes::ElidedAnchor { start, end }) =
self.resolver.get_lifetime_res(t.id)
{
debug_assert_eq!(start.plus(1), end);
start
} else {
self.next_node_id()
};
let span = self.tcx.sess.source_map().start_point(t.span).shrink_to_hi();
Lifetime { ident: Ident::new(kw::UnderscoreLifetime, span), id }
});
let lifetime = self.lower_lifetime(®ion);
hir::TyKind::Ref(lifetime, self.lower_mt(mt, itctx))
}
TyKind::PinnedRef(region, mt) => {
let region = region.unwrap_or_else(|| {
let id = if let Some(LifetimeRes::ElidedAnchor { start, end }) =
self.resolver.get_lifetime_res(t.id)
{
debug_assert_eq!(start.plus(1), end);
start
} else {
self.next_node_id()
};
let span = self.tcx.sess.source_map().start_point(t.span).shrink_to_hi();
Lifetime { ident: Ident::new(kw::UnderscoreLifetime, span), id }
});
let lifetime = self.lower_lifetime(®ion);
let kind = hir::TyKind::Ref(lifetime, self.lower_mt(mt, itctx));
let span = self.lower_span(t.span);
let arg = hir::Ty { kind, span, hir_id: self.next_id() };
let args = self.arena.alloc(hir::GenericArgs {
args: self.arena.alloc([hir::GenericArg::Type(self.arena.alloc(arg))]),
constraints: &[],
parenthesized: hir::GenericArgsParentheses::No,
span_ext: span,
});
let path = self.make_lang_item_qpath(LangItem::Pin, span, Some(args));
hir::TyKind::Path(path)
}
TyKind::BareFn(f) => {
let generic_params = self.lower_lifetime_binder(t.id, &f.generic_params);
hir::TyKind::BareFn(self.arena.alloc(hir::BareFnTy {
generic_params,
safety: self.lower_safety(f.safety, hir::Safety::Safe),
abi: self.lower_extern(f.ext),
decl: self.lower_fn_decl(&f.decl, t.id, t.span, FnDeclKind::Pointer, None),
param_names: self.lower_fn_params_to_names(&f.decl),
}))
}
TyKind::Never => hir::TyKind::Never,
TyKind::Tup(tys) => hir::TyKind::Tup(
self.arena.alloc_from_iter(tys.iter().map(|ty| self.lower_ty_direct(ty, itctx))),
),
TyKind::Paren(ty) => {
return self.lower_ty_direct(ty, itctx);
}
TyKind::Path(qself, path) => {
return self.lower_path_ty(t, qself, path, ParamMode::Explicit, itctx);
}
TyKind::ImplicitSelf => {
let hir_id = self.next_id();
let res = self.expect_full_res(t.id);
let res = self.lower_res(res);
hir::TyKind::Path(hir::QPath::Resolved(
None,
self.arena.alloc(hir::Path {
res,
segments: arena_vec![self; hir::PathSegment::new(
Ident::with_dummy_span(kw::SelfUpper),
hir_id,
res
)],
span: self.lower_span(t.span),
}),
))
}
TyKind::Array(ty, length) => hir::TyKind::Array(
self.lower_ty(ty, itctx),
self.lower_array_length_to_const_arg(length),
),
TyKind::Typeof(expr) => hir::TyKind::Typeof(self.lower_anon_const_to_anon_const(expr)),
TyKind::TraitObject(bounds, kind) => {
let mut lifetime_bound = None;
let (bounds, lifetime_bound) = self.with_dyn_type_scope(true, |this| {
let bounds =
this.arena.alloc_from_iter(bounds.iter().filter_map(|bound| match bound {
GenericBound::Trait(ty) => {
let trait_ref = this.lower_poly_trait_ref(ty, itctx);
Some(trait_ref)
}
GenericBound::Outlives(lifetime) => {
if lifetime_bound.is_none() {
lifetime_bound = Some(this.lower_lifetime(lifetime));
}
None
}
GenericBound::Use(_, span) => {
this.dcx()
.span_delayed_bug(*span, "use<> not allowed in dyn types");
None
}
}));
let lifetime_bound =
lifetime_bound.unwrap_or_else(|| this.elided_dyn_bound(t.span));
(bounds, lifetime_bound)
});
hir::TyKind::TraitObject(bounds, lifetime_bound, *kind)
}
TyKind::ImplTrait(def_node_id, bounds) => {
let span = t.span;
match itctx {
ImplTraitContext::OpaqueTy { origin } => {
self.lower_opaque_impl_trait(span, origin, *def_node_id, bounds, itctx)
}
ImplTraitContext::Universal => {
if let Some(span) = bounds.iter().find_map(|bound| match *bound {
ast::GenericBound::Use(_, span) => Some(span),
_ => None,
}) {
self.tcx.dcx().emit_err(errors::NoPreciseCapturesOnApit { span });
}
let def_id = self.local_def_id(*def_node_id);
let name = self.tcx.item_name(def_id.to_def_id());
let ident = Ident::new(name, span);
let (param, bounds, path) = self.lower_universal_param_and_bounds(
*def_node_id,
span,
ident,
bounds,
);
self.impl_trait_defs.push(param);
if let Some(bounds) = bounds {
self.impl_trait_bounds.push(bounds);
}
path
}
ImplTraitContext::FeatureGated(position, feature) => {
let guar = self
.tcx
.sess
.create_feature_err(
MisplacedImplTrait {
span: t.span,
position: DiagArgFromDisplay(&position),
},
feature,
)
.emit();
hir::TyKind::Err(guar)
}
ImplTraitContext::Disallowed(position) => {
let guar = self.dcx().emit_err(MisplacedImplTrait {
span: t.span,
position: DiagArgFromDisplay(&position),
});
hir::TyKind::Err(guar)
}
}
}
TyKind::Pat(ty, pat) => hir::TyKind::Pat(self.lower_ty(ty, itctx), self.lower_pat(pat)),
TyKind::MacCall(_) => {
span_bug!(t.span, "`TyKind::MacCall` should have been expanded by now")
}
TyKind::CVarArgs => {
let guar = self.dcx().span_delayed_bug(
t.span,
"`TyKind::CVarArgs` should have been handled elsewhere",
);
hir::TyKind::Err(guar)
}
TyKind::Dummy => panic!("`TyKind::Dummy` should never be lowered"),
};
hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.lower_node_id(t.id) }
}
#[instrument(level = "debug", skip(self), ret)]
fn lower_opaque_impl_trait(
&mut self,
span: Span,
origin: hir::OpaqueTyOrigin<LocalDefId>,
opaque_ty_node_id: NodeId,
bounds: &GenericBounds,
itctx: ImplTraitContext,
) -> hir::TyKind<'hir> {
let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::OpaqueTy, span, None);
match origin {
rustc_hir::OpaqueTyOrigin::FnReturn { in_trait_or_impl: Some(_), .. } => {
if !self.tcx.features().precise_capturing_in_traits()
&& let Some(span) = bounds.iter().find_map(|bound| match *bound {
ast::GenericBound::Use(_, span) => Some(span),
_ => None,
})
{
let mut diag =
self.tcx.dcx().create_err(errors::NoPreciseCapturesOnRpitit { span });
add_feature_diagnostics(
&mut diag,
self.tcx.sess,
sym::precise_capturing_in_traits,
);
diag.emit();
}
}
_ => {}
}
self.lower_opaque_inner(opaque_ty_node_id, origin, opaque_ty_span, |this| {
this.lower_param_bounds(bounds, itctx)
})
}
fn lower_opaque_inner(
&mut self,
opaque_ty_node_id: NodeId,
origin: hir::OpaqueTyOrigin<LocalDefId>,
opaque_ty_span: Span,
lower_item_bounds: impl FnOnce(&mut Self) -> &'hir [hir::GenericBound<'hir>],
) -> hir::TyKind<'hir> {
let opaque_ty_def_id = self.local_def_id(opaque_ty_node_id);
let opaque_ty_hir_id = self.lower_node_id(opaque_ty_node_id);
debug!(?opaque_ty_def_id, ?opaque_ty_hir_id);
let bounds = lower_item_bounds(self);
let opaque_ty_def = hir::OpaqueTy {
hir_id: opaque_ty_hir_id,
def_id: opaque_ty_def_id,
bounds,
origin,
span: self.lower_span(opaque_ty_span),
};
let opaque_ty_def = self.arena.alloc(opaque_ty_def);
hir::TyKind::OpaqueDef(opaque_ty_def)
}
fn lower_precise_capturing_args(
&mut self,
precise_capturing_args: &[PreciseCapturingArg],
) -> &'hir [hir::PreciseCapturingArg<'hir>] {
self.arena.alloc_from_iter(precise_capturing_args.iter().map(|arg| match arg {
PreciseCapturingArg::Lifetime(lt) => {
hir::PreciseCapturingArg::Lifetime(self.lower_lifetime(lt))
}
PreciseCapturingArg::Arg(path, id) => {
let [segment] = path.segments.as_slice() else {
panic!();
};
let res = self.resolver.get_partial_res(*id).map_or(Res::Err, |partial_res| {
partial_res.full_res().expect("no partial res expected for precise capture arg")
});
hir::PreciseCapturingArg::Param(hir::PreciseCapturingNonLifetimeArg {
hir_id: self.lower_node_id(*id),
ident: self.lower_ident(segment.ident),
res: self.lower_res(res),
})
}
}))
}
fn lower_fn_params_to_names(&mut self, decl: &FnDecl) -> &'hir [Ident] {
self.arena.alloc_from_iter(decl.inputs.iter().map(|param| match param.pat.kind {
PatKind::Ident(_, ident, _) => self.lower_ident(ident),
_ => Ident::new(kw::Empty, self.lower_span(param.pat.span)),
}))
}
#[instrument(level = "debug", skip(self))]
fn lower_fn_decl(
&mut self,
decl: &FnDecl,
fn_node_id: NodeId,
fn_span: Span,
kind: FnDeclKind,
coro: Option<CoroutineKind>,
) -> &'hir hir::FnDecl<'hir> {
let c_variadic = decl.c_variadic();
let mut inputs = &decl.inputs[..];
if c_variadic {
inputs = &inputs[..inputs.len() - 1];
}
let inputs = self.arena.alloc_from_iter(inputs.iter().map(|param| {
let itctx = match kind {
FnDeclKind::Fn | FnDeclKind::Inherent | FnDeclKind::Impl | FnDeclKind::Trait => {
ImplTraitContext::Universal
}
FnDeclKind::ExternFn => {
ImplTraitContext::Disallowed(ImplTraitPosition::ExternFnParam)
}
FnDeclKind::Closure => {
ImplTraitContext::Disallowed(ImplTraitPosition::ClosureParam)
}
FnDeclKind::Pointer => {
ImplTraitContext::Disallowed(ImplTraitPosition::PointerParam)
}
};
self.lower_ty_direct(¶m.ty, itctx)
}));
let output = match coro {
Some(coro) => {
let fn_def_id = self.local_def_id(fn_node_id);
self.lower_coroutine_fn_ret_ty(&decl.output, fn_def_id, coro, kind, fn_span)
}
None => match &decl.output {
FnRetTy::Ty(ty) => {
let itctx = match kind {
FnDeclKind::Fn | FnDeclKind::Inherent => ImplTraitContext::OpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn {
parent: self.local_def_id(fn_node_id),
in_trait_or_impl: None,
},
},
FnDeclKind::Trait => ImplTraitContext::OpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn {
parent: self.local_def_id(fn_node_id),
in_trait_or_impl: Some(hir::RpitContext::Trait),
},
},
FnDeclKind::Impl => ImplTraitContext::OpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn {
parent: self.local_def_id(fn_node_id),
in_trait_or_impl: Some(hir::RpitContext::TraitImpl),
},
},
FnDeclKind::ExternFn => {
ImplTraitContext::Disallowed(ImplTraitPosition::ExternFnReturn)
}
FnDeclKind::Closure => {
ImplTraitContext::Disallowed(ImplTraitPosition::ClosureReturn)
}
FnDeclKind::Pointer => {
ImplTraitContext::Disallowed(ImplTraitPosition::PointerReturn)
}
};
hir::FnRetTy::Return(self.lower_ty(ty, itctx))
}
FnRetTy::Default(span) => hir::FnRetTy::DefaultReturn(self.lower_span(*span)),
},
};
self.arena.alloc(hir::FnDecl {
inputs,
output,
c_variadic,
lifetime_elision_allowed: self.resolver.lifetime_elision_allowed.contains(&fn_node_id),
implicit_self: decl.inputs.get(0).map_or(hir::ImplicitSelfKind::None, |arg| {
let is_mutable_pat = matches!(
arg.pat.kind,
PatKind::Ident(hir::BindingMode(_, Mutability::Mut), ..)
);
match &arg.ty.kind {
TyKind::ImplicitSelf if is_mutable_pat => hir::ImplicitSelfKind::Mut,
TyKind::ImplicitSelf => hir::ImplicitSelfKind::Imm,
TyKind::Ref(_, mt) | TyKind::PinnedRef(_, mt)
if mt.ty.kind.is_implicit_self() =>
{
match mt.mutbl {
hir::Mutability::Not => hir::ImplicitSelfKind::RefImm,
hir::Mutability::Mut => hir::ImplicitSelfKind::RefMut,
}
}
_ => hir::ImplicitSelfKind::None,
}
}),
})
}
#[instrument(level = "debug", skip(self))]
fn lower_coroutine_fn_ret_ty(
&mut self,
output: &FnRetTy,
fn_def_id: LocalDefId,
coro: CoroutineKind,
fn_kind: FnDeclKind,
fn_span: Span,
) -> hir::FnRetTy<'hir> {
let span = self.lower_span(fn_span);
let (opaque_ty_node_id, allowed_features) = match coro {
CoroutineKind::Async { return_impl_trait_id, .. } => (return_impl_trait_id, None),
CoroutineKind::Gen { return_impl_trait_id, .. } => (return_impl_trait_id, None),
CoroutineKind::AsyncGen { return_impl_trait_id, .. } => {
(return_impl_trait_id, Some(Lrc::clone(&self.allow_async_iterator)))
}
};
let opaque_ty_span =
self.mark_span_with_reason(DesugaringKind::Async, span, allowed_features);
let in_trait_or_impl = match fn_kind {
FnDeclKind::Trait => Some(hir::RpitContext::Trait),
FnDeclKind::Impl => Some(hir::RpitContext::TraitImpl),
FnDeclKind::Fn | FnDeclKind::Inherent => None,
FnDeclKind::ExternFn | FnDeclKind::Closure | FnDeclKind::Pointer => unreachable!(),
};
let opaque_ty_ref = self.lower_opaque_inner(
opaque_ty_node_id,
hir::OpaqueTyOrigin::AsyncFn { parent: fn_def_id, in_trait_or_impl },
opaque_ty_span,
|this| {
let bound = this.lower_coroutine_fn_output_type_to_bound(
output,
coro,
opaque_ty_span,
ImplTraitContext::OpaqueTy {
origin: hir::OpaqueTyOrigin::FnReturn {
parent: fn_def_id,
in_trait_or_impl,
},
},
);
arena_vec![this; bound]
},
);
let opaque_ty = self.ty(opaque_ty_span, opaque_ty_ref);
hir::FnRetTy::Return(self.arena.alloc(opaque_ty))
}
fn lower_coroutine_fn_output_type_to_bound(
&mut self,
output: &FnRetTy,
coro: CoroutineKind,
opaque_ty_span: Span,
itctx: ImplTraitContext,
) -> hir::GenericBound<'hir> {
let output_ty = match output {
FnRetTy::Ty(ty) => {
self.lower_ty(ty, itctx)
}
FnRetTy::Default(ret_ty_span) => self.arena.alloc(self.ty_tup(*ret_ty_span, &[])),
};
let (assoc_ty_name, trait_lang_item) = match coro {
CoroutineKind::Async { .. } => (sym::Output, hir::LangItem::Future),
CoroutineKind::Gen { .. } => (sym::Item, hir::LangItem::Iterator),
CoroutineKind::AsyncGen { .. } => (sym::Item, hir::LangItem::AsyncIterator),
};
let bound_args = self.arena.alloc(hir::GenericArgs {
args: &[],
constraints: arena_vec![self; self.assoc_ty_binding(assoc_ty_name, opaque_ty_span, output_ty)],
parenthesized: hir::GenericArgsParentheses::No,
span_ext: DUMMY_SP,
});
hir::GenericBound::Trait(hir::PolyTraitRef {
bound_generic_params: &[],
modifiers: hir::TraitBoundModifiers::NONE,
trait_ref: hir::TraitRef {
path: self.make_lang_item_path(trait_lang_item, opaque_ty_span, Some(bound_args)),
hir_ref_id: self.next_id(),
},
span: opaque_ty_span,
})
}
#[instrument(level = "trace", skip(self))]
fn lower_param_bound(
&mut self,
tpb: &GenericBound,
itctx: ImplTraitContext,
) -> hir::GenericBound<'hir> {
match tpb {
GenericBound::Trait(p) => hir::GenericBound::Trait(self.lower_poly_trait_ref(p, itctx)),
GenericBound::Outlives(lifetime) => {
hir::GenericBound::Outlives(self.lower_lifetime(lifetime))
}
GenericBound::Use(args, span) => hir::GenericBound::Use(
self.lower_precise_capturing_args(args),
self.lower_span(*span),
),
}
}
fn lower_lifetime(&mut self, l: &Lifetime) -> &'hir hir::Lifetime {
let ident = self.lower_ident(l.ident);
self.new_named_lifetime(l.id, l.id, ident)
}
#[instrument(level = "debug", skip(self))]
fn new_named_lifetime_with_res(
&mut self,
id: NodeId,
ident: Ident,
res: LifetimeRes,
) -> &'hir hir::Lifetime {
let res = match res {
LifetimeRes::Param { param, .. } => hir::LifetimeName::Param(param),
LifetimeRes::Fresh { param, .. } => {
let param = self.local_def_id(param);
hir::LifetimeName::Param(param)
}
LifetimeRes::Infer => hir::LifetimeName::Infer,
LifetimeRes::Static { .. } => hir::LifetimeName::Static,
LifetimeRes::Error => hir::LifetimeName::Error,
res => panic!(
"Unexpected lifetime resolution {:?} for {:?} at {:?}",
res, ident, ident.span
),
};
debug!(?res);
self.arena.alloc(hir::Lifetime {
hir_id: self.lower_node_id(id),
ident: self.lower_ident(ident),
res,
})
}
#[instrument(level = "debug", skip(self))]
fn new_named_lifetime(
&mut self,
id: NodeId,
new_id: NodeId,
ident: Ident,
) -> &'hir hir::Lifetime {
let res = self.resolver.get_lifetime_res(id).unwrap_or(LifetimeRes::Error);
self.new_named_lifetime_with_res(new_id, ident, res)
}
fn lower_generic_params_mut<'s>(
&'s mut self,
params: &'s [GenericParam],
source: hir::GenericParamSource,
) -> impl Iterator<Item = hir::GenericParam<'hir>> + Captures<'a> + Captures<'s> {
params.iter().map(move |param| self.lower_generic_param(param, source))
}
fn lower_generic_params(
&mut self,
params: &[GenericParam],
source: hir::GenericParamSource,
) -> &'hir [hir::GenericParam<'hir>] {
self.arena.alloc_from_iter(self.lower_generic_params_mut(params, source))
}
#[instrument(level = "trace", skip(self))]
fn lower_generic_param(
&mut self,
param: &GenericParam,
source: hir::GenericParamSource,
) -> hir::GenericParam<'hir> {
let (name, kind) = self.lower_generic_param_kind(param, source);
let hir_id = self.lower_node_id(param.id);
self.lower_attrs(hir_id, ¶m.attrs);
hir::GenericParam {
hir_id,
def_id: self.local_def_id(param.id),
name,
span: self.lower_span(param.span()),
pure_wrt_drop: attr::contains_name(¶m.attrs, sym::may_dangle),
kind,
colon_span: param.colon_span.map(|s| self.lower_span(s)),
source,
}
}
fn lower_generic_param_kind(
&mut self,
param: &GenericParam,
source: hir::GenericParamSource,
) -> (hir::ParamName, hir::GenericParamKind<'hir>) {
match ¶m.kind {
GenericParamKind::Lifetime => {
let param_name =
if let Some(LifetimeRes::Error) = self.resolver.get_lifetime_res(param.id) {
ParamName::Error
} else {
let ident = self.lower_ident(param.ident);
ParamName::Plain(ident)
};
let kind =
hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit };
(param_name, kind)
}
GenericParamKind::Type { default, .. } => {
let default = default
.as_ref()
.filter(|_| match source {
hir::GenericParamSource::Generics => true,
hir::GenericParamSource::Binder => {
self.dcx().emit_err(errors::GenericParamDefaultInBinder {
span: param.span(),
});
false
}
})
.map(|def| {
self.lower_ty(
def,
ImplTraitContext::Disallowed(ImplTraitPosition::GenericDefault),
)
});
let kind = hir::GenericParamKind::Type { default, synthetic: false };
(hir::ParamName::Plain(self.lower_ident(param.ident)), kind)
}
GenericParamKind::Const { ty, kw_span: _, default } => {
let ty = self
.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::GenericDefault));
let default = default
.as_ref()
.filter(|_| match source {
hir::GenericParamSource::Generics => true,
hir::GenericParamSource::Binder => {
self.dcx().emit_err(errors::GenericParamDefaultInBinder {
span: param.span(),
});
false
}
})
.map(|def| self.lower_anon_const_to_const_arg(def));
(
hir::ParamName::Plain(self.lower_ident(param.ident)),
hir::GenericParamKind::Const { ty, default, synthetic: false },
)
}
}
}
fn lower_trait_ref(
&mut self,
modifiers: ast::TraitBoundModifiers,
p: &TraitRef,
itctx: ImplTraitContext,
) -> hir::TraitRef<'hir> {
let path = match self.lower_qpath(
p.ref_id,
&None,
&p.path,
ParamMode::Explicit,
AllowReturnTypeNotation::No,
itctx,
Some(modifiers),
) {
hir::QPath::Resolved(None, path) => path,
qpath => panic!("lower_trait_ref: unexpected QPath `{qpath:?}`"),
};
hir::TraitRef { path, hir_ref_id: self.lower_node_id(p.ref_id) }
}
#[instrument(level = "debug", skip(self))]
fn lower_poly_trait_ref(
&mut self,
p: &PolyTraitRef,
itctx: ImplTraitContext,
) -> hir::PolyTraitRef<'hir> {
let bound_generic_params =
self.lower_lifetime_binder(p.trait_ref.ref_id, &p.bound_generic_params);
let trait_ref = self.lower_trait_ref(p.modifiers, &p.trait_ref, itctx);
let modifiers = self.lower_trait_bound_modifiers(p.modifiers);
hir::PolyTraitRef {
bound_generic_params,
modifiers,
trait_ref,
span: self.lower_span(p.span),
}
}
fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext) -> hir::MutTy<'hir> {
hir::MutTy { ty: self.lower_ty(&mt.ty, itctx), mutbl: mt.mutbl }
}
#[instrument(level = "debug", skip(self), ret)]
fn lower_param_bounds(
&mut self,
bounds: &[GenericBound],
itctx: ImplTraitContext,
) -> hir::GenericBounds<'hir> {
self.arena.alloc_from_iter(self.lower_param_bounds_mut(bounds, itctx))
}
fn lower_param_bounds_mut<'s>(
&'s mut self,
bounds: &'s [GenericBound],
itctx: ImplTraitContext,
) -> impl Iterator<Item = hir::GenericBound<'hir>> + Captures<'s> + Captures<'a> {
bounds.iter().map(move |bound| self.lower_param_bound(bound, itctx))
}
#[instrument(level = "debug", skip(self), ret)]
fn lower_universal_param_and_bounds(
&mut self,
node_id: NodeId,
span: Span,
ident: Ident,
bounds: &[GenericBound],
) -> (hir::GenericParam<'hir>, Option<hir::WherePredicate<'hir>>, hir::TyKind<'hir>) {
let def_id = self.local_def_id(node_id);
let span = self.lower_span(span);
let param = hir::GenericParam {
hir_id: self.lower_node_id(node_id),
def_id,
name: ParamName::Plain(self.lower_ident(ident)),
pure_wrt_drop: false,
span,
kind: hir::GenericParamKind::Type { default: None, synthetic: true },
colon_span: None,
source: hir::GenericParamSource::Generics,
};
let preds = self.lower_generic_bound_predicate(
ident,
node_id,
&GenericParamKind::Type { default: None },
bounds,
None,
span,
ImplTraitContext::Universal,
hir::PredicateOrigin::ImplTrait,
);
let hir_id = self.next_id();
let res = Res::Def(DefKind::TyParam, def_id.to_def_id());
let ty = hir::TyKind::Path(hir::QPath::Resolved(
None,
self.arena.alloc(hir::Path {
span,
res,
segments:
arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)],
}),
));
(param, preds, ty)
}
fn lower_block_expr(&mut self, b: &Block) -> hir::Expr<'hir> {
let block = self.lower_block(b, false);
self.expr_block(block)
}
fn lower_array_length_to_const_arg(&mut self, c: &AnonConst) -> &'hir hir::ConstArg<'hir> {
match c.value.kind {
ExprKind::Underscore => {
if self.tcx.features().generic_arg_infer() {
let ct_kind = hir::ConstArgKind::Infer(self.lower_span(c.value.span));
self.arena
.alloc(hir::ConstArg { hir_id: self.lower_node_id(c.id), kind: ct_kind })
} else {
feature_err(
&self.tcx.sess,
sym::generic_arg_infer,
c.value.span,
fluent_generated::ast_lowering_underscore_array_length_unstable,
)
.stash(c.value.span, StashKey::UnderscoreForArrayLengths);
self.lower_anon_const_to_const_arg(c)
}
}
_ => self.lower_anon_const_to_const_arg(c),
}
}
#[instrument(level = "debug", skip(self))]
fn lower_const_path_to_const_arg(
&mut self,
path: &Path,
res: Res<NodeId>,
ty_id: NodeId,
span: Span,
) -> &'hir hir::ConstArg<'hir> {
let tcx = self.tcx;
let ct_kind = if path.is_potential_trivial_const_arg()
&& (tcx.features().min_generic_const_args()
|| matches!(res, Res::Def(DefKind::ConstParam, _)))
{
let qpath = self.lower_qpath(
ty_id,
&None,
path,
ParamMode::Optional,
AllowReturnTypeNotation::No,
ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
hir::ConstArgKind::Path(qpath)
} else {
let parent_def_id = self.current_hir_id_owner.def_id;
let node_id = self.next_node_id();
let span = self.lower_span(span);
let def_id =
self.create_def(parent_def_id, node_id, kw::Empty, DefKind::AnonConst, span);
let hir_id = self.lower_node_id(node_id);
let path_expr = Expr {
id: ty_id,
kind: ExprKind::Path(None, path.clone()),
span,
attrs: AttrVec::new(),
tokens: None,
};
let ct = self.with_new_scopes(span, |this| {
self.arena.alloc(hir::AnonConst {
def_id,
hir_id,
body: this.lower_const_body(path_expr.span, Some(&path_expr)),
span,
})
});
hir::ConstArgKind::Anon(ct)
};
self.arena.alloc(hir::ConstArg { hir_id: self.next_id(), kind: ct_kind })
}
fn lower_anon_const_to_const_arg(&mut self, anon: &AnonConst) -> &'hir hir::ConstArg<'hir> {
self.arena.alloc(self.lower_anon_const_to_const_arg_direct(anon))
}
#[instrument(level = "debug", skip(self))]
fn lower_anon_const_to_const_arg_direct(&mut self, anon: &AnonConst) -> hir::ConstArg<'hir> {
let tcx = self.tcx;
let expr = if let ExprKind::Block(block, _) = &anon.value.kind
&& let [stmt] = block.stmts.as_slice()
&& let StmtKind::Expr(expr) = &stmt.kind
&& let ExprKind::Path(..) = &expr.kind
{
expr
} else {
&anon.value
};
let maybe_res =
self.resolver.get_partial_res(expr.id).and_then(|partial_res| partial_res.full_res());
if let ExprKind::Path(None, path) = &expr.kind
&& path.is_potential_trivial_const_arg()
&& (tcx.features().min_generic_const_args()
|| matches!(maybe_res, Some(Res::Def(DefKind::ConstParam, _))))
{
let qpath = self.lower_qpath(
expr.id,
&None,
path,
ParamMode::Optional,
AllowReturnTypeNotation::No,
ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
return ConstArg {
hir_id: self.lower_node_id(anon.id),
kind: hir::ConstArgKind::Path(qpath),
};
}
let lowered_anon = self.lower_anon_const_to_anon_const(anon);
ConstArg { hir_id: self.next_id(), kind: hir::ConstArgKind::Anon(lowered_anon) }
}
fn lower_anon_const_to_anon_const(&mut self, c: &AnonConst) -> &'hir hir::AnonConst {
self.arena.alloc(self.with_new_scopes(c.value.span, |this| {
let def_id = this.local_def_id(c.id);
let hir_id = this.lower_node_id(c.id);
hir::AnonConst {
def_id,
hir_id,
body: this.lower_const_body(c.value.span, Some(&c.value)),
span: this.lower_span(c.value.span),
}
}))
}
fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource {
match u {
CompilerGenerated => hir::UnsafeSource::CompilerGenerated,
UserProvided => hir::UnsafeSource::UserProvided,
}
}
fn lower_trait_bound_modifiers(
&mut self,
modifiers: TraitBoundModifiers,
) -> hir::TraitBoundModifiers {
hir::TraitBoundModifiers { constness: modifiers.constness, polarity: modifiers.polarity }
}
fn stmt(&mut self, span: Span, kind: hir::StmtKind<'hir>) -> hir::Stmt<'hir> {
hir::Stmt { span: self.lower_span(span), kind, hir_id: self.next_id() }
}
fn stmt_expr(&mut self, span: Span, expr: hir::Expr<'hir>) -> hir::Stmt<'hir> {
self.stmt(span, hir::StmtKind::Expr(self.arena.alloc(expr)))
}
fn stmt_let_pat(
&mut self,
attrs: Option<&'hir [Attribute]>,
span: Span,
init: Option<&'hir hir::Expr<'hir>>,
pat: &'hir hir::Pat<'hir>,
source: hir::LocalSource,
) -> hir::Stmt<'hir> {
let hir_id = self.next_id();
if let Some(a) = attrs {
debug_assert!(!a.is_empty());
self.attrs.insert(hir_id.local_id, a);
}
let local = hir::LetStmt {
hir_id,
init,
pat,
els: None,
source,
span: self.lower_span(span),
ty: None,
};
self.stmt(span, hir::StmtKind::Let(self.arena.alloc(local)))
}
fn block_expr(&mut self, expr: &'hir hir::Expr<'hir>) -> &'hir hir::Block<'hir> {
self.block_all(expr.span, &[], Some(expr))
}
fn block_all(
&mut self,
span: Span,
stmts: &'hir [hir::Stmt<'hir>],
expr: Option<&'hir hir::Expr<'hir>>,
) -> &'hir hir::Block<'hir> {
let blk = hir::Block {
stmts,
expr,
hir_id: self.next_id(),
rules: hir::BlockCheckMode::DefaultBlock,
span: self.lower_span(span),
targeted_by_break: false,
};
self.arena.alloc(blk)
}
fn pat_cf_continue(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> {
let field = self.single_pat_field(span, pat);
self.pat_lang_item_variant(span, hir::LangItem::ControlFlowContinue, field)
}
fn pat_cf_break(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> {
let field = self.single_pat_field(span, pat);
self.pat_lang_item_variant(span, hir::LangItem::ControlFlowBreak, field)
}
fn pat_some(&mut self, span: Span, pat: &'hir hir::Pat<'hir>) -> &'hir hir::Pat<'hir> {
let field = self.single_pat_field(span, pat);
self.pat_lang_item_variant(span, hir::LangItem::OptionSome, field)
}
fn pat_none(&mut self, span: Span) -> &'hir hir::Pat<'hir> {
self.pat_lang_item_variant(span, hir::LangItem::OptionNone, &[])
}
fn single_pat_field(
&mut self,
span: Span,
pat: &'hir hir::Pat<'hir>,
) -> &'hir [hir::PatField<'hir>] {
let field = hir::PatField {
hir_id: self.next_id(),
ident: Ident::new(sym::integer(0), self.lower_span(span)),
is_shorthand: false,
pat,
span: self.lower_span(span),
};
arena_vec![self; field]
}
fn pat_lang_item_variant(
&mut self,
span: Span,
lang_item: hir::LangItem,
fields: &'hir [hir::PatField<'hir>],
) -> &'hir hir::Pat<'hir> {
let qpath = hir::QPath::LangItem(lang_item, self.lower_span(span));
self.pat(span, hir::PatKind::Struct(qpath, fields, false))
}
fn pat_ident(&mut self, span: Span, ident: Ident) -> (&'hir hir::Pat<'hir>, HirId) {
self.pat_ident_binding_mode(span, ident, hir::BindingMode::NONE)
}
fn pat_ident_mut(&mut self, span: Span, ident: Ident) -> (hir::Pat<'hir>, HirId) {
self.pat_ident_binding_mode_mut(span, ident, hir::BindingMode::NONE)
}
fn pat_ident_binding_mode(
&mut self,
span: Span,
ident: Ident,
bm: hir::BindingMode,
) -> (&'hir hir::Pat<'hir>, HirId) {
let (pat, hir_id) = self.pat_ident_binding_mode_mut(span, ident, bm);
(self.arena.alloc(pat), hir_id)
}
fn pat_ident_binding_mode_mut(
&mut self,
span: Span,
ident: Ident,
bm: hir::BindingMode,
) -> (hir::Pat<'hir>, HirId) {
let hir_id = self.next_id();
(
hir::Pat {
hir_id,
kind: hir::PatKind::Binding(bm, hir_id, self.lower_ident(ident), None),
span: self.lower_span(span),
default_binding_modes: true,
},
hir_id,
)
}
fn pat(&mut self, span: Span, kind: hir::PatKind<'hir>) -> &'hir hir::Pat<'hir> {
self.arena.alloc(hir::Pat {
hir_id: self.next_id(),
kind,
span: self.lower_span(span),
default_binding_modes: true,
})
}
fn pat_without_dbm(&mut self, span: Span, kind: hir::PatKind<'hir>) -> hir::Pat<'hir> {
hir::Pat {
hir_id: self.next_id(),
kind,
span: self.lower_span(span),
default_binding_modes: false,
}
}
fn ty_path(&mut self, mut hir_id: HirId, span: Span, qpath: hir::QPath<'hir>) -> hir::Ty<'hir> {
let kind = match qpath {
hir::QPath::Resolved(None, path) => {
match path.res {
Res::Def(DefKind::Trait | DefKind::TraitAlias, _) => {
let principal = hir::PolyTraitRef {
bound_generic_params: &[],
modifiers: hir::TraitBoundModifiers::NONE,
trait_ref: hir::TraitRef { path, hir_ref_id: hir_id },
span: self.lower_span(span),
};
hir_id = self.next_id();
hir::TyKind::TraitObject(
arena_vec![self; principal],
self.elided_dyn_bound(span),
TraitObjectSyntax::None,
)
}
_ => hir::TyKind::Path(hir::QPath::Resolved(None, path)),
}
}
_ => hir::TyKind::Path(qpath),
};
hir::Ty { hir_id, kind, span: self.lower_span(span) }
}
fn elided_dyn_bound(&mut self, span: Span) -> &'hir hir::Lifetime {
let r = hir::Lifetime {
hir_id: self.next_id(),
ident: Ident::new(kw::Empty, self.lower_span(span)),
res: hir::LifetimeName::ImplicitObjectLifetimeDefault,
};
debug!("elided_dyn_bound: r={:?}", r);
self.arena.alloc(r)
}
}
struct GenericArgsCtor<'hir> {
args: SmallVec<[hir::GenericArg<'hir>; 4]>,
constraints: &'hir [hir::AssocItemConstraint<'hir>],
parenthesized: hir::GenericArgsParentheses,
span: Span,
}
impl<'hir> GenericArgsCtor<'hir> {
fn is_empty(&self) -> bool {
self.args.is_empty()
&& self.constraints.is_empty()
&& self.parenthesized == hir::GenericArgsParentheses::No
}
fn into_generic_args(self, this: &LoweringContext<'_, 'hir>) -> &'hir hir::GenericArgs<'hir> {
let ga = hir::GenericArgs {
args: this.arena.alloc_from_iter(self.args),
constraints: self.constraints,
parenthesized: self.parenthesized,
span_ext: this.lower_span(self.span),
};
this.arena.alloc(ga)
}
}