mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
rust/compiler/rustc_ast_lowering/src/item.rs
Santiago Pastorino 40bcbed3c7
Avoid explicitly handling res when is not needed
2022-08-04 11:26:58 -03:00

1514 lines
62 KiB
Rust
Raw Blame History

use super::ResolverAstLoweringExt;
use super::{AstOwner, ImplTraitContext, ImplTraitPosition};
use super::{FnDeclKind, LoweringContext, ParamMode};
use rustc_ast::ptr::P;
use rustc_ast::visit::AssocCtxt;
use rustc_ast::*;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::sorted_map::SortedMap;
use rustc_errors::struct_span_err;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
use rustc_hir::PredicateOrigin;
use rustc_index::vec::{Idx, IndexVec};
use rustc_middle::ty::{DefIdTree, ResolverAstLowering, TyCtxt};
use rustc_span::source_map::DesugaringKind;
use rustc_span::symbol::{kw, sym, Ident};
use rustc_span::Span;
use rustc_target::spec::abi;
use smallvec::{smallvec, SmallVec};
use std::iter;
pub(super) struct ItemLowerer<'a, 'hir> {
pub(super) tcx: TyCtxt<'hir>,
pub(super) resolver: &'a mut ResolverAstLowering,
pub(super) ast_index: &'a IndexVec<LocalDefId, AstOwner<'a>>,
pub(super) owners: &'a mut IndexVec<LocalDefId, hir::MaybeOwner<&'hir hir::OwnerInfo<'hir>>>,
}
/// When we have a ty alias we *may* have two where clauses. To give the best diagnostics, we set the span
/// to the where clause that is preferred, if it exists. Otherwise, it sets the span to the other where
/// clause if it exists.
fn add_ty_alias_where_clause(
generics: &mut ast::Generics,
mut where_clauses: (TyAliasWhereClause, TyAliasWhereClause),
prefer_first: bool,
) {
if !prefer_first {
where_clauses = (where_clauses.1, where_clauses.0);
}
if where_clauses.0.0 || !where_clauses.1.0 {
generics.where_clause.has_where_token = where_clauses.0.0;
generics.where_clause.span = where_clauses.0.1;
} else {
generics.where_clause.has_where_token = where_clauses.1.0;
generics.where_clause.span = where_clauses.1.1;
}
}
impl<'a, 'hir> ItemLowerer<'a, 'hir> {
fn with_lctx(
&mut self,
owner: NodeId,
f: impl FnOnce(&mut LoweringContext<'_, 'hir>) -> hir::OwnerNode<'hir>,
) {
let mut lctx = LoweringContext {
// Pseudo-globals.
tcx: self.tcx,
resolver: self.resolver,
arena: self.tcx.hir_arena,
// HirId handling.
bodies: Vec::new(),
attrs: SortedMap::default(),
children: FxHashMap::default(),
current_hir_id_owner: CRATE_DEF_ID,
item_local_id_counter: hir::ItemLocalId::new(0),
node_id_to_local_id: Default::default(),
local_id_to_def_id: SortedMap::new(),
trait_map: Default::default(),
// Lowering state.
catch_scope: None,
loop_scope: None,
is_in_loop_condition: false,
is_in_trait_impl: false,
is_in_dyn_type: false,
generator_kind: None,
task_context: None,
current_item: None,
impl_trait_defs: Vec::new(),
impl_trait_bounds: Vec::new(),
allow_try_trait: Some([sym::try_trait_v2, sym::yeet_desugar_details][..].into()),
allow_gen_future: Some([sym::gen_future][..].into()),
allow_into_future: Some([sym::into_future][..].into()),
};
lctx.with_hir_id_owner(owner, |lctx| f(lctx));
for (def_id, info) in lctx.children {
self.owners.ensure_contains_elem(def_id, || hir::MaybeOwner::Phantom);
debug_assert!(matches!(self.owners[def_id], hir::MaybeOwner::Phantom));
self.owners[def_id] = info;
}
}
pub(super) fn lower_node(
&mut self,
def_id: LocalDefId,
) -> hir::MaybeOwner<&'hir hir::OwnerInfo<'hir>> {
self.owners.ensure_contains_elem(def_id, || hir::MaybeOwner::Phantom);
if let hir::MaybeOwner::Phantom = self.owners[def_id] {
let node = self.ast_index[def_id];
match node {
AstOwner::NonOwner => {}
AstOwner::Crate(c) => self.lower_crate(c),
AstOwner::Item(item) => self.lower_item(item),
AstOwner::AssocItem(item, ctxt) => self.lower_assoc_item(item, ctxt),
AstOwner::ForeignItem(item) => self.lower_foreign_item(item),
}
}
self.owners[def_id]
}
#[instrument(level = "debug", skip(self, c))]
fn lower_crate(&mut self, c: &Crate) {
debug_assert_eq!(self.resolver.node_id_to_def_id[&CRATE_NODE_ID], CRATE_DEF_ID);
self.with_lctx(CRATE_NODE_ID, |lctx| {
let module = lctx.lower_mod(&c.items, &c.spans);
lctx.lower_attrs(hir::CRATE_HIR_ID, &c.attrs);
hir::OwnerNode::Crate(lctx.arena.alloc(module))
})
}
#[instrument(level = "debug", skip(self))]
fn lower_item(&mut self, item: &Item) {
self.with_lctx(item.id, |lctx| hir::OwnerNode::Item(lctx.lower_item(item)))
}
fn lower_assoc_item(&mut self, item: &AssocItem, ctxt: AssocCtxt) {
let def_id = self.resolver.node_id_to_def_id[&item.id];
let parent_id = self.tcx.local_parent(def_id);
let parent_hir = self.lower_node(parent_id).unwrap();
self.with_lctx(item.id, |lctx| {
// Evaluate with the lifetimes in `params` in-scope.
// This is used to track which lifetimes have already been defined,
// and which need to be replicated when lowering an async fn.
match parent_hir.node().expect_item().kind {
hir::ItemKind::Impl(hir::Impl { ref of_trait, .. }) => {
lctx.is_in_trait_impl = of_trait.is_some();
}
_ => {}
};
match ctxt {
AssocCtxt::Trait => hir::OwnerNode::TraitItem(lctx.lower_trait_item(item)),
AssocCtxt::Impl => hir::OwnerNode::ImplItem(lctx.lower_impl_item(item)),
}
})
}
fn lower_foreign_item(&mut self, item: &ForeignItem) {
self.with_lctx(item.id, |lctx| hir::OwnerNode::ForeignItem(lctx.lower_foreign_item(item)))
}
}
impl<'hir> LoweringContext<'_, 'hir> {
pub(super) fn lower_mod(&mut self, items: &[P<Item>], spans: &ModSpans) -> hir::Mod<'hir> {
hir::Mod {
spans: hir::ModSpans {
inner_span: self.lower_span(spans.inner_span),
inject_use_span: self.lower_span(spans.inject_use_span),
},
item_ids: self.arena.alloc_from_iter(items.iter().flat_map(|x| self.lower_item_ref(x))),
}
}
pub(super) fn lower_item_ref(&mut self, i: &Item) -> SmallVec<[hir::ItemId; 1]> {
let mut node_ids = smallvec![hir::ItemId { def_id: self.local_def_id(i.id) }];
if let ItemKind::Use(ref use_tree) = &i.kind {
self.lower_item_id_use_tree(use_tree, i.id, &mut node_ids);
}
node_ids
}
fn lower_item_id_use_tree(
&mut self,
tree: &UseTree,
base_id: NodeId,
vec: &mut SmallVec<[hir::ItemId; 1]>,
) {
match tree.kind {
UseTreeKind::Nested(ref nested_vec) => {
for &(ref nested, id) in nested_vec {
vec.push(hir::ItemId { def_id: self.local_def_id(id) });
self.lower_item_id_use_tree(nested, id, vec);
}
}
UseTreeKind::Glob => {}
UseTreeKind::Simple(_, id1, id2) => {
for (_, &id) in
iter::zip(self.expect_full_res_from_use(base_id).skip(1), &[id1, id2])
{
vec.push(hir::ItemId { def_id: self.local_def_id(id) });
}
}
}
}
fn lower_item(&mut self, i: &Item) -> &'hir hir::Item<'hir> {
let mut ident = i.ident;
let vis_span = self.lower_span(i.vis.span);
let hir_id = self.lower_node_id(i.id);
let attrs = self.lower_attrs(hir_id, &i.attrs);
let kind = self.lower_item_kind(i.span, i.id, hir_id, &mut ident, attrs, vis_span, &i.kind);
let item = hir::Item {
def_id: hir_id.expect_owner(),
ident: self.lower_ident(ident),
kind,
vis_span,
span: self.lower_span(i.span),
};
self.arena.alloc(item)
}
fn lower_item_kind(
&mut self,
span: Span,
id: NodeId,
hir_id: hir::HirId,
ident: &mut Ident,
attrs: Option<&'hir [Attribute]>,
vis_span: Span,
i: &ItemKind,
) -> hir::ItemKind<'hir> {
match *i {
ItemKind::ExternCrate(orig_name) => hir::ItemKind::ExternCrate(orig_name),
ItemKind::Use(ref use_tree) => {
// Start with an empty prefix.
let prefix = Path { segments: vec![], span: use_tree.span, tokens: None };
self.lower_use_tree(use_tree, &prefix, id, vis_span, ident, attrs)
}
ItemKind::Static(ref t, m, ref e) => {
let (ty, body_id) = self.lower_const_item(t, span, e.as_deref());
hir::ItemKind::Static(ty, m, body_id)
}
ItemKind::Const(_, ref t, ref e) => {
let (ty, body_id) = self.lower_const_item(t, span, e.as_deref());
hir::ItemKind::Const(ty, body_id)
}
ItemKind::Fn(box Fn {
sig: FnSig { ref decl, header, span: fn_sig_span },
ref generics,
ref body,
..
}) => {
self.with_new_scopes(|this| {
this.current_item = Some(ident.span);
// Note: we don't need to change the return type from `T` to
// `impl Future<Output = T>` here because lower_body
// only cares about the input argument patterns in the function
// declaration (decl), not the return types.
let asyncness = header.asyncness;
let body_id =
this.lower_maybe_async_body(span, &decl, asyncness, body.as_deref());
let itctx = ImplTraitContext::Universal;
let (generics, decl) = this.lower_generics(generics, id, itctx, |this| {
let ret_id = asyncness.opt_return_id();
this.lower_fn_decl(&decl, Some(id), FnDeclKind::Fn, ret_id)
});
let sig = hir::FnSig {
decl,
header: this.lower_fn_header(header),
span: this.lower_span(fn_sig_span),
};
hir::ItemKind::Fn(sig, generics, body_id)
})
}
ItemKind::Mod(_, ref mod_kind) => match mod_kind {
ModKind::Loaded(items, _, spans) => {
hir::ItemKind::Mod(self.lower_mod(items, spans))
}
ModKind::Unloaded => panic!("`mod` items should have been loaded by now"),
},
ItemKind::ForeignMod(ref fm) => hir::ItemKind::ForeignMod {
abi: fm.abi.map_or(abi::Abi::FALLBACK, |abi| self.lower_abi(abi)),
items: self
.arena
.alloc_from_iter(fm.items.iter().map(|x| self.lower_foreign_item_ref(x))),
},
ItemKind::GlobalAsm(ref asm) => {
hir::ItemKind::GlobalAsm(self.lower_inline_asm(span, asm))
}
ItemKind::TyAlias(box TyAlias {
ref generics,
where_clauses,
ty: Some(ref ty),
..
}) => {
// We lower
//
// type Foo = impl Trait
//
// to
//
// type Foo = Foo1
// opaque type Foo1: Trait
let mut generics = generics.clone();
add_ty_alias_where_clause(&mut generics, where_clauses, true);
let (generics, ty) = self.lower_generics(
&generics,
id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| this.lower_ty(ty, ImplTraitContext::TypeAliasesOpaqueTy),
);
hir::ItemKind::TyAlias(ty, generics)
}
ItemKind::TyAlias(box TyAlias {
ref generics, ref where_clauses, ty: None, ..
}) => {
let mut generics = generics.clone();
add_ty_alias_where_clause(&mut generics, *where_clauses, true);
let (generics, ty) = self.lower_generics(
&generics,
id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| this.arena.alloc(this.ty(span, hir::TyKind::Err)),
);
hir::ItemKind::TyAlias(ty, generics)
}
ItemKind::Enum(ref enum_definition, ref generics) => {
let (generics, variants) = self.lower_generics(
generics,
id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| {
this.arena.alloc_from_iter(
enum_definition.variants.iter().map(|x| this.lower_variant(x)),
)
},
);
hir::ItemKind::Enum(hir::EnumDef { variants }, generics)
}
ItemKind::Struct(ref struct_def, ref generics) => {
let (generics, struct_def) = self.lower_generics(
generics,
id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| this.lower_variant_data(hir_id, struct_def),
);
hir::ItemKind::Struct(struct_def, generics)
}
ItemKind::Union(ref vdata, ref generics) => {
let (generics, vdata) = self.lower_generics(
generics,
id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| this.lower_variant_data(hir_id, vdata),
);
hir::ItemKind::Union(vdata, generics)
}
ItemKind::Impl(box Impl {
unsafety,
polarity,
defaultness,
constness,
generics: ref ast_generics,
of_trait: ref trait_ref,
self_ty: ref ty,
items: ref impl_items,
}) => {
// Lower the "impl header" first. This ordering is important
// for in-band lifetimes! Consider `'a` here:
//
// impl Foo<'a> for u32 {
// fn method(&'a self) { .. }
// }
//
// Because we start by lowering the `Foo<'a> for u32`
// part, we will add `'a` to the list of generics on
// the impl. When we then encounter it later in the
// method, it will not be considered an in-band
// lifetime to be added, but rather a reference to a
// parent lifetime.
let itctx = ImplTraitContext::Universal;
let (generics, (trait_ref, lowered_ty)) =
self.lower_generics(ast_generics, id, itctx, |this| {
let trait_ref = trait_ref.as_ref().map(|trait_ref| {
this.lower_trait_ref(
trait_ref,
ImplTraitContext::Disallowed(ImplTraitPosition::Trait),
)
});
let lowered_ty = this
.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
(trait_ref, lowered_ty)
});
let new_impl_items = self
.arena
.alloc_from_iter(impl_items.iter().map(|item| self.lower_impl_item_ref(item)));
// `defaultness.has_value()` is never called for an `impl`, always `true` in order
// to not cause an assertion failure inside the `lower_defaultness` function.
let has_val = true;
let (defaultness, defaultness_span) = self.lower_defaultness(defaultness, has_val);
let polarity = match polarity {
ImplPolarity::Positive => ImplPolarity::Positive,
ImplPolarity::Negative(s) => ImplPolarity::Negative(self.lower_span(s)),
};
hir::ItemKind::Impl(self.arena.alloc(hir::Impl {
unsafety: self.lower_unsafety(unsafety),
polarity,
defaultness,
defaultness_span,
constness: self.lower_constness(constness),
generics,
of_trait: trait_ref,
self_ty: lowered_ty,
items: new_impl_items,
}))
}
ItemKind::Trait(box Trait {
is_auto,
unsafety,
ref generics,
ref bounds,
ref items,
}) => {
let (generics, (unsafety, items, bounds)) = self.lower_generics(
generics,
id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| {
let bounds = this.lower_param_bounds(
bounds,
ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
);
let items = this.arena.alloc_from_iter(
items.iter().map(|item| this.lower_trait_item_ref(item)),
);
let unsafety = this.lower_unsafety(unsafety);
(unsafety, items, bounds)
},
);
hir::ItemKind::Trait(is_auto, unsafety, generics, bounds, items)
}
ItemKind::TraitAlias(ref generics, ref bounds) => {
let (generics, bounds) = self.lower_generics(
generics,
id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| {
this.lower_param_bounds(
bounds,
ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
)
},
);
hir::ItemKind::TraitAlias(generics, bounds)
}
ItemKind::MacroDef(MacroDef { ref body, macro_rules }) => {
let body = P(self.lower_mac_args(body));
let macro_kind = self.resolver.decl_macro_kind(self.local_def_id(id));
hir::ItemKind::Macro(ast::MacroDef { body, macro_rules }, macro_kind)
}
ItemKind::MacCall(..) => {
panic!("`TyMac` should have been expanded by now")
}
}
}
fn lower_const_item(
&mut self,
ty: &Ty,
span: Span,
body: Option<&Expr>,
) -> (&'hir hir::Ty<'hir>, hir::BodyId) {
let ty = self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
(ty, self.lower_const_body(span, body))
}
#[instrument(level = "debug", skip(self))]
fn lower_use_tree(
&mut self,
tree: &UseTree,
prefix: &Path,
id: NodeId,
vis_span: Span,
ident: &mut Ident,
attrs: Option<&'hir [Attribute]>,
) -> hir::ItemKind<'hir> {
let path = &tree.prefix;
let segments = prefix.segments.iter().chain(path.segments.iter()).cloned().collect();
match tree.kind {
UseTreeKind::Simple(rename, id1, id2) => {
*ident = tree.ident();
// First, apply the prefix to the path.
let mut path = Path { segments, span: path.span, tokens: None };
// Correctly resolve `self` imports.
if path.segments.len() > 1
&& path.segments.last().unwrap().ident.name == kw::SelfLower
{
let _ = path.segments.pop();
if rename.is_none() {
*ident = path.segments.last().unwrap().ident;
}
}
let mut resolutions = self.expect_full_res_from_use(id).fuse();
// We want to return *something* from this function, so hold onto the first item
// for later.
let ret_res = self.lower_res(resolutions.next().unwrap_or(Res::Err));
// Here, we are looping over namespaces, if they exist for the definition
// being imported. We only handle type and value namespaces because we
// won't be dealing with macros in the rest of the compiler.
// Essentially a single `use` which imports two names is desugared into
// two imports.
for new_node_id in [id1, id2] {
let new_id = self.local_def_id(new_node_id);
let Some(res) = resolutions.next() else {
// Associate an HirId to both ids even if there is no resolution.
let _old = self.children.insert(
new_id,
hir::MaybeOwner::NonOwner(hir::HirId::make_owner(new_id)),
);
debug_assert!(_old.is_none());
continue;
};
let ident = *ident;
let mut path = path.clone();
for seg in &mut path.segments {
seg.id = self.next_node_id();
}
let span = path.span;
self.with_hir_id_owner(new_node_id, |this| {
let res = this.lower_res(res);
let path = this.lower_path_extra(res, &path, ParamMode::Explicit);
let kind = hir::ItemKind::Use(path, hir::UseKind::Single);
if let Some(attrs) = attrs {
this.attrs.insert(hir::ItemLocalId::new(0), attrs);
}
let item = hir::Item {
def_id: new_id,
ident: this.lower_ident(ident),
kind,
vis_span,
span: this.lower_span(span),
};
hir::OwnerNode::Item(this.arena.alloc(item))
});
}
let path = self.lower_path_extra(ret_res, &path, ParamMode::Explicit);
hir::ItemKind::Use(path, hir::UseKind::Single)
}
UseTreeKind::Glob => {
let path = self.lower_path(
id,
&Path { segments, span: path.span, tokens: None },
ParamMode::Explicit,
);
hir::ItemKind::Use(path, hir::UseKind::Glob)
}
UseTreeKind::Nested(ref trees) => {
// Nested imports are desugared into simple imports.
// So, if we start with
//
// ```
// pub(x) use foo::{a, b};
// ```
//
// we will create three items:
//
// ```
// pub(x) use foo::a;
// pub(x) use foo::b;
// pub(x) use foo::{}; // <-- this is called the `ListStem`
// ```
//
// The first two are produced by recursively invoking
// `lower_use_tree` (and indeed there may be things
// like `use foo::{a::{b, c}}` and so forth). They
// wind up being directly added to
// `self.items`. However, the structure of this
// function also requires us to return one item, and
// for that we return the `{}` import (called the
// `ListStem`).
let prefix = Path { segments, span: prefix.span.to(path.span), tokens: None };
// Add all the nested `PathListItem`s to the HIR.
for &(ref use_tree, id) in trees {
let new_hir_id = self.local_def_id(id);
let mut prefix = prefix.clone();
// Give the segments new node-ids since they are being cloned.
for seg in &mut prefix.segments {
seg.id = self.next_node_id();
}
// Each `use` import is an item and thus are owners of the
// names in the path. Up to this point the nested import is
// the current owner, since we want each desugared import to
// own its own names, we have to adjust the owner before
// lowering the rest of the import.
self.with_hir_id_owner(id, |this| {
let mut ident = *ident;
let kind =
this.lower_use_tree(use_tree, &prefix, id, vis_span, &mut ident, attrs);
if let Some(attrs) = attrs {
this.attrs.insert(hir::ItemLocalId::new(0), attrs);
}
let item = hir::Item {
def_id: new_hir_id,
ident: this.lower_ident(ident),
kind,
vis_span,
span: this.lower_span(use_tree.span),
};
hir::OwnerNode::Item(this.arena.alloc(item))
});
}
let res = self.expect_full_res_from_use(id).next().unwrap_or(Res::Err);
let res = self.lower_res(res);
let path = self.lower_path_extra(res, &prefix, ParamMode::Explicit);
hir::ItemKind::Use(path, hir::UseKind::ListStem)
}
}
}
fn lower_foreign_item(&mut self, i: &ForeignItem) -> &'hir hir::ForeignItem<'hir> {
let hir_id = self.lower_node_id(i.id);
let def_id = hir_id.expect_owner();
self.lower_attrs(hir_id, &i.attrs);
let item = hir::ForeignItem {
def_id,
ident: self.lower_ident(i.ident),
kind: match i.kind {
ForeignItemKind::Fn(box Fn { ref sig, ref generics, .. }) => {
let fdec = &sig.decl;
let itctx = ImplTraitContext::Universal;
let (generics, (fn_dec, fn_args)) =
self.lower_generics(generics, i.id, itctx, |this| {
(
// Disallow `impl Trait` in foreign items.
this.lower_fn_decl(fdec, None, FnDeclKind::ExternFn, None),
this.lower_fn_params_to_names(fdec),
)
});
hir::ForeignItemKind::Fn(fn_dec, fn_args, generics)
}
ForeignItemKind::Static(ref t, m, _) => {
let ty =
self.lower_ty(t, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
hir::ForeignItemKind::Static(ty, m)
}
ForeignItemKind::TyAlias(..) => hir::ForeignItemKind::Type,
ForeignItemKind::MacCall(_) => panic!("macro shouldn't exist here"),
},
vis_span: self.lower_span(i.vis.span),
span: self.lower_span(i.span),
};
self.arena.alloc(item)
}
fn lower_foreign_item_ref(&mut self, i: &ForeignItem) -> hir::ForeignItemRef {
hir::ForeignItemRef {
id: hir::ForeignItemId { def_id: self.local_def_id(i.id) },
ident: self.lower_ident(i.ident),
span: self.lower_span(i.span),
}
}
fn lower_variant(&mut self, v: &Variant) -> hir::Variant<'hir> {
let id = self.lower_node_id(v.id);
self.lower_attrs(id, &v.attrs);
hir::Variant {
id,
data: self.lower_variant_data(id, &v.data),
disr_expr: v.disr_expr.as_ref().map(|e| self.lower_anon_const(e)),
ident: self.lower_ident(v.ident),
span: self.lower_span(v.span),
}
}
fn lower_variant_data(
&mut self,
parent_id: hir::HirId,
vdata: &VariantData,
) -> hir::VariantData<'hir> {
match *vdata {
VariantData::Struct(ref fields, recovered) => hir::VariantData::Struct(
self.arena
.alloc_from_iter(fields.iter().enumerate().map(|f| self.lower_field_def(f))),
recovered,
),
VariantData::Tuple(ref fields, id) => {
let ctor_id = self.lower_node_id(id);
self.alias_attrs(ctor_id, parent_id);
hir::VariantData::Tuple(
self.arena.alloc_from_iter(
fields.iter().enumerate().map(|f| self.lower_field_def(f)),
),
ctor_id,
)
}
VariantData::Unit(id) => {
let ctor_id = self.lower_node_id(id);
self.alias_attrs(ctor_id, parent_id);
hir::VariantData::Unit(ctor_id)
}
}
}
fn lower_field_def(&mut self, (index, f): (usize, &FieldDef)) -> hir::FieldDef<'hir> {
let ty = if let TyKind::Path(ref qself, ref path) = f.ty.kind {
let t = self.lower_path_ty(
&f.ty,
qself,
path,
ParamMode::ExplicitNamed, // no `'_` in declarations (Issue #61124)
ImplTraitContext::Disallowed(ImplTraitPosition::Path),
);
self.arena.alloc(t)
} else {
self.lower_ty(&f.ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type))
};
let hir_id = self.lower_node_id(f.id);
self.lower_attrs(hir_id, &f.attrs);
hir::FieldDef {
span: self.lower_span(f.span),
hir_id,
ident: match f.ident {
Some(ident) => self.lower_ident(ident),
// FIXME(jseyfried): positional field hygiene.
None => Ident::new(sym::integer(index), self.lower_span(f.span)),
},
vis_span: self.lower_span(f.vis.span),
ty,
}
}
fn lower_trait_item(&mut self, i: &AssocItem) -> &'hir hir::TraitItem<'hir> {
let hir_id = self.lower_node_id(i.id);
let trait_item_def_id = hir_id.expect_owner();
let (generics, kind, has_default) = match i.kind {
AssocItemKind::Const(_, ref ty, ref default) => {
let ty = self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
let body = default.as_ref().map(|x| self.lower_const_body(i.span, Some(x)));
(hir::Generics::empty(), hir::TraitItemKind::Const(ty, body), body.is_some())
}
AssocItemKind::Fn(box Fn { ref sig, ref generics, body: None, .. }) => {
let names = self.lower_fn_params_to_names(&sig.decl);
let (generics, sig) =
self.lower_method_sig(generics, sig, i.id, FnDeclKind::Trait, None);
(generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Required(names)), false)
}
AssocItemKind::Fn(box Fn { ref sig, ref generics, body: Some(ref body), .. }) => {
let asyncness = sig.header.asyncness;
let body_id =
self.lower_maybe_async_body(i.span, &sig.decl, asyncness, Some(&body));
let (generics, sig) = self.lower_method_sig(
generics,
sig,
i.id,
FnDeclKind::Trait,
asyncness.opt_return_id(),
);
(generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Provided(body_id)), true)
}
AssocItemKind::TyAlias(box TyAlias {
ref generics,
where_clauses,
ref bounds,
ref ty,
..
}) => {
let mut generics = generics.clone();
add_ty_alias_where_clause(&mut generics, where_clauses, false);
let (generics, kind) = self.lower_generics(
&generics,
i.id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| {
let ty = ty.as_ref().map(|x| {
this.lower_ty(x, ImplTraitContext::Disallowed(ImplTraitPosition::Type))
});
hir::TraitItemKind::Type(
this.lower_param_bounds(
bounds,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
),
ty,
)
},
);
(generics, kind, ty.is_some())
}
AssocItemKind::MacCall(..) => panic!("macro item shouldn't exist at this point"),
};
self.lower_attrs(hir_id, &i.attrs);
let item = hir::TraitItem {
def_id: trait_item_def_id,
ident: self.lower_ident(i.ident),
generics,
kind,
span: self.lower_span(i.span),
defaultness: hir::Defaultness::Default { has_value: has_default },
};
self.arena.alloc(item)
}
fn lower_trait_item_ref(&mut self, i: &AssocItem) -> hir::TraitItemRef {
let kind = match &i.kind {
AssocItemKind::Const(..) => hir::AssocItemKind::Const,
AssocItemKind::TyAlias(..) => hir::AssocItemKind::Type,
AssocItemKind::Fn(box Fn { sig, .. }) => {
hir::AssocItemKind::Fn { has_self: sig.decl.has_self() }
}
AssocItemKind::MacCall(..) => unimplemented!(),
};
let id = hir::TraitItemId { def_id: self.local_def_id(i.id) };
hir::TraitItemRef {
id,
ident: self.lower_ident(i.ident),
span: self.lower_span(i.span),
kind,
}
}
/// Construct `ExprKind::Err` for the given `span`.
pub(crate) fn expr_err(&mut self, span: Span) -> hir::Expr<'hir> {
self.expr(span, hir::ExprKind::Err, AttrVec::new())
}
fn lower_impl_item(&mut self, i: &AssocItem) -> &'hir hir::ImplItem<'hir> {
// Since `default impl` is not yet implemented, this is always true in impls.
let has_value = true;
let (defaultness, _) = self.lower_defaultness(i.kind.defaultness(), has_value);
let (generics, kind) = match &i.kind {
AssocItemKind::Const(_, ty, expr) => {
let ty = self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
(
hir::Generics::empty(),
hir::ImplItemKind::Const(ty, self.lower_const_body(i.span, expr.as_deref())),
)
}
AssocItemKind::Fn(box Fn { sig, generics, body, .. }) => {
self.current_item = Some(i.span);
let asyncness = sig.header.asyncness;
let body_id =
self.lower_maybe_async_body(i.span, &sig.decl, asyncness, body.as_deref());
let (generics, sig) = self.lower_method_sig(
generics,
sig,
i.id,
if self.is_in_trait_impl { FnDeclKind::Impl } else { FnDeclKind::Inherent },
asyncness.opt_return_id(),
);
(generics, hir::ImplItemKind::Fn(sig, body_id))
}
AssocItemKind::TyAlias(box TyAlias { generics, where_clauses, ty, .. }) => {
let mut generics = generics.clone();
add_ty_alias_where_clause(&mut generics, *where_clauses, false);
self.lower_generics(
&generics,
i.id,
ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
|this| match ty {
None => {
let ty = this.arena.alloc(this.ty(i.span, hir::TyKind::Err));
hir::ImplItemKind::TyAlias(ty)
}
Some(ty) => {
let ty = this.lower_ty(ty, ImplTraitContext::TypeAliasesOpaqueTy);
hir::ImplItemKind::TyAlias(ty)
}
},
)
}
AssocItemKind::MacCall(..) => panic!("`TyMac` should have been expanded by now"),
};
let hir_id = self.lower_node_id(i.id);
self.lower_attrs(hir_id, &i.attrs);
let item = hir::ImplItem {
def_id: hir_id.expect_owner(),
ident: self.lower_ident(i.ident),
generics,
kind,
vis_span: self.lower_span(i.vis.span),
span: self.lower_span(i.span),
defaultness,
};
self.arena.alloc(item)
}
fn lower_impl_item_ref(&mut self, i: &AssocItem) -> hir::ImplItemRef {
hir::ImplItemRef {
id: hir::ImplItemId { def_id: self.local_def_id(i.id) },
ident: self.lower_ident(i.ident),
span: self.lower_span(i.span),
kind: match &i.kind {
AssocItemKind::Const(..) => hir::AssocItemKind::Const,
AssocItemKind::TyAlias(..) => hir::AssocItemKind::Type,
AssocItemKind::Fn(box Fn { sig, .. }) => {
hir::AssocItemKind::Fn { has_self: sig.decl.has_self() }
}
AssocItemKind::MacCall(..) => unimplemented!(),
},
trait_item_def_id: self.resolver.get_partial_res(i.id).map(|r| r.base_res().def_id()),
}
}
fn lower_defaultness(
&self,
d: Defaultness,
has_value: bool,
) -> (hir::Defaultness, Option<Span>) {
match d {
Defaultness::Default(sp) => {
(hir::Defaultness::Default { has_value }, Some(self.lower_span(sp)))
}
Defaultness::Final => {
assert!(has_value);
(hir::Defaultness::Final, None)
}
}
}
fn record_body(
&mut self,
params: &'hir [hir::Param<'hir>],
value: hir::Expr<'hir>,
) -> hir::BodyId {
let body = hir::Body { generator_kind: self.generator_kind, params, value };
let id = body.id();
debug_assert_eq!(id.hir_id.owner, self.current_hir_id_owner);
self.bodies.push((id.hir_id.local_id, self.arena.alloc(body)));
id
}
pub(super) fn lower_body(
&mut self,
f: impl FnOnce(&mut Self) -> (&'hir [hir::Param<'hir>], hir::Expr<'hir>),
) -> hir::BodyId {
let prev_gen_kind = self.generator_kind.take();
let task_context = self.task_context.take();
let (parameters, result) = f(self);
let body_id = self.record_body(parameters, result);
self.task_context = task_context;
self.generator_kind = prev_gen_kind;
body_id
}
fn lower_param(&mut self, param: &Param) -> hir::Param<'hir> {
let hir_id = self.lower_node_id(param.id);
self.lower_attrs(hir_id, &param.attrs);
hir::Param {
hir_id,
pat: self.lower_pat(&param.pat),
ty_span: self.lower_span(param.ty.span),
span: self.lower_span(param.span),
}
}
pub(super) fn lower_fn_body(
&mut self,
decl: &FnDecl,
body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
) -> hir::BodyId {
self.lower_body(|this| {
(
this.arena.alloc_from_iter(decl.inputs.iter().map(|x| this.lower_param(x))),
body(this),
)
})
}
fn lower_fn_body_block(
&mut self,
span: Span,
decl: &FnDecl,
body: Option<&Block>,
) -> hir::BodyId {
self.lower_fn_body(decl, |this| this.lower_block_expr_opt(span, body))
}
fn lower_block_expr_opt(&mut self, span: Span, block: Option<&Block>) -> hir::Expr<'hir> {
match block {
Some(block) => self.lower_block_expr(block),
None => self.expr_err(span),
}
}
pub(super) fn lower_const_body(&mut self, span: Span, expr: Option<&Expr>) -> hir::BodyId {
self.lower_body(|this| {
(
&[],
match expr {
Some(expr) => this.lower_expr_mut(expr),
None => this.expr_err(span),
},
)
})
}
fn lower_maybe_async_body(
&mut self,
span: Span,
decl: &FnDecl,
asyncness: Async,
body: Option<&Block>,
) -> hir::BodyId {
let closure_id = match asyncness {
Async::Yes { closure_id, .. } => closure_id,
Async::No => return self.lower_fn_body_block(span, decl, body),
};
self.lower_body(|this| {
let mut parameters: Vec<hir::Param<'_>> = Vec::new();
let mut statements: Vec<hir::Stmt<'_>> = Vec::new();
// Async function parameters are lowered into the closure body so that they are
// captured and so that the drop order matches the equivalent non-async functions.
//
// from:
//
// async fn foo(<pattern>: <ty>, <pattern>: <ty>, <pattern>: <ty>) {
// <body>
// }
//
// into:
//
// fn foo(__arg0: <ty>, __arg1: <ty>, __arg2: <ty>) {
// async move {
// let __arg2 = __arg2;
// let <pattern> = __arg2;
// let __arg1 = __arg1;
// let <pattern> = __arg1;
// let __arg0 = __arg0;
// let <pattern> = __arg0;
// drop-temps { <body> } // see comments later in fn for details
// }
// }
//
// If `<pattern>` is a simple ident, then it is lowered to a single
// `let <pattern> = <pattern>;` statement as an optimization.
//
// Note that the body is embedded in `drop-temps`; an
// equivalent desugaring would be `return { <body>
// };`. The key point is that we wish to drop all the
// let-bound variables and temporaries created in the body
// (and its tail expression!) before we drop the
// parameters (c.f. rust-lang/rust#64512).
for (index, parameter) in decl.inputs.iter().enumerate() {
let parameter = this.lower_param(parameter);
let span = parameter.pat.span;
// Check if this is a binding pattern, if so, we can optimize and avoid adding a
// `let <pat> = __argN;` statement. In this case, we do not rename the parameter.
let (ident, is_simple_parameter) = match parameter.pat.kind {
hir::PatKind::Binding(
hir::BindingAnnotation::Unannotated | hir::BindingAnnotation::Mutable,
_,
ident,
_,
) => (ident, true),
// For `ref mut` or wildcard arguments, we can't reuse the binding, but
// we can keep the same name for the parameter.
// This lets rustdoc render it correctly in documentation.
hir::PatKind::Binding(_, _, ident, _) => (ident, false),
hir::PatKind::Wild => {
(Ident::with_dummy_span(rustc_span::symbol::kw::Underscore), false)
}
_ => {
// Replace the ident for bindings that aren't simple.
let name = format!("__arg{}", index);
let ident = Ident::from_str(&name);
(ident, false)
}
};
let desugared_span = this.mark_span_with_reason(DesugaringKind::Async, span, None);
// Construct a parameter representing `__argN: <ty>` to replace the parameter of the
// async function.
//
// If this is the simple case, this parameter will end up being the same as the
// original parameter, but with a different pattern id.
let stmt_attrs = this.attrs.get(&parameter.hir_id.local_id).copied();
let (new_parameter_pat, new_parameter_id) = this.pat_ident(desugared_span, ident);
let new_parameter = hir::Param {
hir_id: parameter.hir_id,
pat: new_parameter_pat,
ty_span: this.lower_span(parameter.ty_span),
span: this.lower_span(parameter.span),
};
if is_simple_parameter {
// If this is the simple case, then we only insert one statement that is
// `let <pat> = <pat>;`. We re-use the original argument's pattern so that
// `HirId`s are densely assigned.
let expr = this.expr_ident(desugared_span, ident, new_parameter_id);
let stmt = this.stmt_let_pat(
stmt_attrs,
desugared_span,
Some(expr),
parameter.pat,
hir::LocalSource::AsyncFn,
);
statements.push(stmt);
} else {
// If this is not the simple case, then we construct two statements:
//
// ```
// let __argN = __argN;
// let <pat> = __argN;
// ```
//
// The first statement moves the parameter into the closure and thus ensures
// that the drop order is correct.
//
// The second statement creates the bindings that the user wrote.
// Construct the `let mut __argN = __argN;` statement. It must be a mut binding
// because the user may have specified a `ref mut` binding in the next
// statement.
let (move_pat, move_id) = this.pat_ident_binding_mode(
desugared_span,
ident,
hir::BindingAnnotation::Mutable,
);
let move_expr = this.expr_ident(desugared_span, ident, new_parameter_id);
let move_stmt = this.stmt_let_pat(
None,
desugared_span,
Some(move_expr),
move_pat,
hir::LocalSource::AsyncFn,
);
// Construct the `let <pat> = __argN;` statement. We re-use the original
// parameter's pattern so that `HirId`s are densely assigned.
let pattern_expr = this.expr_ident(desugared_span, ident, move_id);
let pattern_stmt = this.stmt_let_pat(
stmt_attrs,
desugared_span,
Some(pattern_expr),
parameter.pat,
hir::LocalSource::AsyncFn,
);
statements.push(move_stmt);
statements.push(pattern_stmt);
};
parameters.push(new_parameter);
}
let body_span = body.map_or(span, |b| b.span);
let async_expr = this.make_async_expr(
CaptureBy::Value,
closure_id,
None,
body_span,
hir::AsyncGeneratorKind::Fn,
|this| {
// Create a block from the user's function body:
let user_body = this.lower_block_expr_opt(body_span, body);
// Transform into `drop-temps { <user-body> }`, an expression:
let desugared_span =
this.mark_span_with_reason(DesugaringKind::Async, user_body.span, None);
let user_body = this.expr_drop_temps(
desugared_span,
this.arena.alloc(user_body),
AttrVec::new(),
);
// As noted above, create the final block like
//
// ```
// {
// let $param_pattern = $raw_param;
// ...
// drop-temps { <user-body> }
// }
// ```
let body = this.block_all(
desugared_span,
this.arena.alloc_from_iter(statements),
Some(user_body),
);
this.expr_block(body, AttrVec::new())
},
);
(
this.arena.alloc_from_iter(parameters),
this.expr(body_span, async_expr, AttrVec::new()),
)
})
}
fn lower_method_sig(
&mut self,
generics: &Generics,
sig: &FnSig,
id: NodeId,
kind: FnDeclKind,
is_async: Option<NodeId>,
) -> (&'hir hir::Generics<'hir>, hir::FnSig<'hir>) {
let header = self.lower_fn_header(sig.header);
let itctx = ImplTraitContext::Universal;
let (generics, decl) = self.lower_generics(generics, id, itctx, |this| {
this.lower_fn_decl(&sig.decl, Some(id), kind, is_async)
});
(generics, hir::FnSig { header, decl, span: self.lower_span(sig.span) })
}
fn lower_fn_header(&mut self, h: FnHeader) -> hir::FnHeader {
hir::FnHeader {
unsafety: self.lower_unsafety(h.unsafety),
asyncness: self.lower_asyncness(h.asyncness),
constness: self.lower_constness(h.constness),
abi: self.lower_extern(h.ext),
}
}
pub(super) fn lower_abi(&mut self, abi: StrLit) -> abi::Abi {
abi::lookup(abi.symbol_unescaped.as_str()).unwrap_or_else(|| {
self.error_on_invalid_abi(abi);
abi::Abi::Rust
})
}
pub(super) fn lower_extern(&mut self, ext: Extern) -> abi::Abi {
match ext {
Extern::None => abi::Abi::Rust,
Extern::Implicit(_) => abi::Abi::FALLBACK,
Extern::Explicit(abi, _) => self.lower_abi(abi),
}
}
fn error_on_invalid_abi(&self, abi: StrLit) {
struct_span_err!(self.tcx.sess, abi.span, E0703, "invalid ABI: found `{}`", abi.symbol)
.span_label(abi.span, "invalid ABI")
.help(&format!("valid ABIs: {}", abi::all_names().join(", ")))
.emit();
}
fn lower_asyncness(&mut self, a: Async) -> hir::IsAsync {
match a {
Async::Yes { .. } => hir::IsAsync::Async,
Async::No => hir::IsAsync::NotAsync,
}
}
fn lower_constness(&mut self, c: Const) -> hir::Constness {
match c {
Const::Yes(_) => hir::Constness::Const,
Const::No => hir::Constness::NotConst,
}
}
pub(super) fn lower_unsafety(&mut self, u: Unsafe) -> hir::Unsafety {
match u {
Unsafe::Yes(_) => hir::Unsafety::Unsafe,
Unsafe::No => hir::Unsafety::Normal,
}
}
/// Return the pair of the lowered `generics` as `hir::Generics` and the evaluation of `f` with
/// the carried impl trait definitions and bounds.
#[instrument(level = "debug", skip(self, f))]
fn lower_generics<T>(
&mut self,
generics: &Generics,
parent_node_id: NodeId,
itctx: ImplTraitContext,
f: impl FnOnce(&mut Self) -> T,
) -> (&'hir hir::Generics<'hir>, T) {
debug_assert!(self.impl_trait_defs.is_empty());
debug_assert!(self.impl_trait_bounds.is_empty());
// Error if `?Trait` bounds in where clauses don't refer directly to type parameters.
// Note: we used to clone these bounds directly onto the type parameter (and avoid lowering
// these into hir when we lower thee where clauses), but this makes it quite difficult to
// keep track of the Span info. Now, `add_implicitly_sized` in `AstConv` checks both param bounds and
// where clauses for `?Sized`.
for pred in &generics.where_clause.predicates {
let WherePredicate::BoundPredicate(ref bound_pred) = *pred else {
continue;
};
let compute_is_param = || {
// Check if the where clause type is a plain type parameter.
match self
.resolver
.get_partial_res(bound_pred.bounded_ty.id)
.map(|d| (d.base_res(), d.unresolved_segments()))
{
Some((Res::Def(DefKind::TyParam, def_id), 0))
if bound_pred.bound_generic_params.is_empty() =>
{
generics
.params
.iter()
.any(|p| def_id == self.local_def_id(p.id).to_def_id())
}
// Either the `bounded_ty` is not a plain type parameter, or
// it's not found in the generic type parameters list.
_ => false,
}
};
// We only need to compute this once per `WherePredicate`, but don't
// need to compute this at all unless there is a Maybe bound.
let mut is_param: Option<bool> = None;
for bound in &bound_pred.bounds {
if !matches!(*bound, GenericBound::Trait(_, TraitBoundModifier::Maybe)) {
continue;
}
let is_param = *is_param.get_or_insert_with(compute_is_param);
if !is_param {
self.diagnostic().span_err(
bound.span(),
"`?Trait` bounds are only permitted at the \
point where a type parameter is declared",
);
}
}
}
let mut predicates: SmallVec<[hir::WherePredicate<'hir>; 4]> = SmallVec::new();
predicates.extend(generics.params.iter().filter_map(|param| {
self.lower_generic_bound_predicate(
param.ident,
param.id,
&param.kind,
&param.bounds,
itctx,
PredicateOrigin::GenericParam,
)
}));
predicates.extend(
generics
.where_clause
.predicates
.iter()
.map(|predicate| self.lower_where_predicate(predicate)),
);
let mut params: SmallVec<[hir::GenericParam<'hir>; 4]> =
self.lower_generic_params_mut(&generics.params).collect();
// Introduce extra lifetimes if late resolution tells us to.
let extra_lifetimes = self.resolver.take_extra_lifetime_params(parent_node_id);
params.extend(extra_lifetimes.into_iter().filter_map(|(ident, node_id, res)| {
self.lifetime_res_to_generic_param(ident, node_id, res)
}));
let has_where_clause_predicates = !generics.where_clause.predicates.is_empty();
let where_clause_span = self.lower_span(generics.where_clause.span);
let span = self.lower_span(generics.span);
let res = f(self);
let impl_trait_defs = std::mem::take(&mut self.impl_trait_defs);
params.extend(impl_trait_defs.into_iter());
let impl_trait_bounds = std::mem::take(&mut self.impl_trait_bounds);
predicates.extend(impl_trait_bounds.into_iter());
let lowered_generics = self.arena.alloc(hir::Generics {
params: self.arena.alloc_from_iter(params),
predicates: self.arena.alloc_from_iter(predicates),
has_where_clause_predicates,
where_clause_span,
span,
});
(lowered_generics, res)
}
pub(super) fn lower_generic_bound_predicate(
&mut self,
ident: Ident,
id: NodeId,
kind: &GenericParamKind,
bounds: &[GenericBound],
itctx: ImplTraitContext,
origin: PredicateOrigin,
) -> Option<hir::WherePredicate<'hir>> {
// Do not create a clause if we do not have anything inside it.
if bounds.is_empty() {
return None;
}
let bounds = self.lower_param_bounds(bounds, itctx);
let ident = self.lower_ident(ident);
let param_span = ident.span;
let span = bounds
.iter()
.fold(Some(param_span.shrink_to_hi()), |span: Option<Span>, bound| {
let bound_span = bound.span();
// We include bounds that come from a `#[derive(_)]` but point at the user's code,
// as we use this method to get a span appropriate for suggestions.
if !bound_span.can_be_used_for_suggestions() {
None
} else if let Some(span) = span {
Some(span.to(bound_span))
} else {
Some(bound_span)
}
})
.unwrap_or(param_span.shrink_to_hi());
match kind {
GenericParamKind::Const { .. } => None,
GenericParamKind::Type { .. } => {
let def_id = self.local_def_id(id).to_def_id();
let ty_path = self.arena.alloc(hir::Path {
span: param_span,
res: Res::Def(DefKind::TyParam, def_id),
segments: self.arena.alloc_from_iter([hir::PathSegment::from_ident(ident)]),
});
let ty_id = self.next_id();
let bounded_ty =
self.ty_path(ty_id, param_span, hir::QPath::Resolved(None, ty_path));
Some(hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
bounded_ty: self.arena.alloc(bounded_ty),
bounds,
span,
bound_generic_params: &[],
origin,
}))
}
GenericParamKind::Lifetime => {
let ident_span = self.lower_span(ident.span);
let ident = self.lower_ident(ident);
let lt_id = self.next_node_id();
let lifetime = self.new_named_lifetime(id, lt_id, ident_span, ident);
Some(hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
lifetime,
span,
bounds,
in_where_clause: false,
}))
}
}
}
fn lower_where_predicate(&mut self, pred: &WherePredicate) -> hir::WherePredicate<'hir> {
match *pred {
WherePredicate::BoundPredicate(WhereBoundPredicate {
ref bound_generic_params,
ref bounded_ty,
ref bounds,
span,
}) => hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
bound_generic_params: self.lower_generic_params(bound_generic_params),
bounded_ty: self
.lower_ty(bounded_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
bounds: self.arena.alloc_from_iter(bounds.iter().map(|bound| {
self.lower_param_bound(
bound,
ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
)
})),
span: self.lower_span(span),
origin: PredicateOrigin::WhereClause,
}),
WherePredicate::RegionPredicate(WhereRegionPredicate {
ref lifetime,
ref bounds,
span,
}) => hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
span: self.lower_span(span),
lifetime: self.lower_lifetime(lifetime),
bounds: self.lower_param_bounds(
bounds,
ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
),
in_where_clause: true,
}),
WherePredicate::EqPredicate(WhereEqPredicate { id, ref lhs_ty, ref rhs_ty, span }) => {
hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
hir_id: self.lower_node_id(id),
lhs_ty: self
.lower_ty(lhs_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
rhs_ty: self
.lower_ty(rhs_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
span: self.lower_span(span),
})
}
}
}
}
Reference in New Issue View Git Blame Copy Permalink