1530 lines
62 KiB
Rust
1530 lines
62 KiB
Rust
use super::{AnonymousLifetimeMode, LoweringContext, ParamMode};
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use super::{ImplTraitContext, ImplTraitPosition};
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use crate::Arena;
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use rustc_ast::node_id::NodeMap;
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use rustc_ast::ptr::P;
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use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
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use rustc_ast::*;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_errors::struct_span_err;
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use rustc_hir as hir;
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use rustc_hir::def::{DefKind, Res};
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use rustc_hir::def_id::LocalDefId;
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use rustc_span::source_map::{respan, DesugaringKind};
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use rustc_span::symbol::{kw, sym, Ident};
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use rustc_span::Span;
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use rustc_target::spec::abi;
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use smallvec::{smallvec, SmallVec};
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use tracing::debug;
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use std::iter;
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use std::mem;
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pub(super) struct ItemLowerer<'a, 'lowering, 'hir> {
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pub(super) lctx: &'a mut LoweringContext<'lowering, 'hir>,
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}
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impl ItemLowerer<'_, '_, '_> {
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fn with_trait_impl_ref(&mut self, impl_ref: &Option<TraitRef>, f: impl FnOnce(&mut Self)) {
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let old = self.lctx.is_in_trait_impl;
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self.lctx.is_in_trait_impl = impl_ref.is_some();
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f(self);
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self.lctx.is_in_trait_impl = old;
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}
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}
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impl<'a> Visitor<'a> for ItemLowerer<'a, '_, '_> {
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fn visit_item(&mut self, item: &'a Item) {
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let mut item_hir_id = None;
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self.lctx.with_hir_id_owner(item.id, |lctx| {
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lctx.without_in_scope_lifetime_defs(|lctx| {
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if let Some(hir_item) = lctx.lower_item(item) {
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let id = lctx.insert_item(hir_item);
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item_hir_id = Some(id);
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}
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})
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});
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if let Some(hir_id) = item_hir_id {
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self.lctx.with_parent_item_lifetime_defs(hir_id, |this| {
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let this = &mut ItemLowerer { lctx: this };
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match item.kind {
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ItemKind::Mod(..) => {
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let def_id = this.lctx.lower_node_id(item.id).expect_owner();
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let old_current_module =
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mem::replace(&mut this.lctx.current_module, def_id);
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visit::walk_item(this, item);
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this.lctx.current_module = old_current_module;
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}
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ItemKind::Impl(box ImplKind { ref of_trait, .. }) => {
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this.with_trait_impl_ref(of_trait, |this| visit::walk_item(this, item));
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}
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_ => visit::walk_item(this, item),
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}
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});
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}
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}
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fn visit_fn(&mut self, fk: FnKind<'a>, sp: Span, _: NodeId) {
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match fk {
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FnKind::Fn(FnCtxt::Foreign, _, sig, _, _) => {
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self.visit_fn_header(&sig.header);
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visit::walk_fn_decl(self, &sig.decl);
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// Don't visit the foreign function body even if it has one, since lowering the
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// body would have no meaning and will have already been caught as a parse error.
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}
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_ => visit::walk_fn(self, fk, sp),
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}
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}
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fn visit_assoc_item(&mut self, item: &'a AssocItem, ctxt: AssocCtxt) {
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self.lctx.with_hir_id_owner(item.id, |lctx| match ctxt {
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AssocCtxt::Trait => {
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let hir_item = lctx.lower_trait_item(item);
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let id = hir_item.trait_item_id();
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lctx.trait_items.insert(id, hir_item);
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lctx.modules.entry(lctx.current_module).or_default().trait_items.insert(id);
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}
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AssocCtxt::Impl => {
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let hir_item = lctx.lower_impl_item(item);
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let id = hir_item.impl_item_id();
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lctx.impl_items.insert(id, hir_item);
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lctx.modules.entry(lctx.current_module).or_default().impl_items.insert(id);
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}
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});
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visit::walk_assoc_item(self, item, ctxt);
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}
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fn visit_foreign_item(&mut self, item: &'a ForeignItem) {
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self.lctx.allocate_hir_id_counter(item.id);
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self.lctx.with_hir_id_owner(item.id, |lctx| {
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let hir_item = lctx.lower_foreign_item(item);
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let id = hir_item.foreign_item_id();
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lctx.foreign_items.insert(id, hir_item);
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lctx.modules.entry(lctx.current_module).or_default().foreign_items.insert(id);
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});
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visit::walk_foreign_item(self, item);
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}
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}
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impl<'hir> LoweringContext<'_, 'hir> {
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// Same as the method above, but accepts `hir::GenericParam`s
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// instead of `ast::GenericParam`s.
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// This should only be used with generics that have already had their
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// in-band lifetimes added. In practice, this means that this function is
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// only used when lowering a child item of a trait or impl.
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fn with_parent_item_lifetime_defs<T>(
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&mut self,
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parent_hir_id: hir::ItemId,
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f: impl FnOnce(&mut LoweringContext<'_, '_>) -> T,
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) -> T {
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let old_len = self.in_scope_lifetimes.len();
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let parent_generics = match self.items.get(&parent_hir_id).unwrap().kind {
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hir::ItemKind::Impl(hir::Impl { ref generics, .. })
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| hir::ItemKind::Trait(_, _, ref generics, ..) => generics.params,
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_ => &[],
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};
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let lt_def_names = parent_generics.iter().filter_map(|param| match param.kind {
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hir::GenericParamKind::Lifetime { .. } => Some(param.name.normalize_to_macros_2_0()),
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_ => None,
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});
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self.in_scope_lifetimes.extend(lt_def_names);
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let res = f(self);
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self.in_scope_lifetimes.truncate(old_len);
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res
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}
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// Clears (and restores) the `in_scope_lifetimes` field. Used when
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// visiting nested items, which never inherit in-scope lifetimes
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// from their surrounding environment.
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fn without_in_scope_lifetime_defs<T>(
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&mut self,
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f: impl FnOnce(&mut LoweringContext<'_, '_>) -> T,
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) -> T {
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let old_in_scope_lifetimes = mem::replace(&mut self.in_scope_lifetimes, vec![]);
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// this vector is only used when walking over impl headers,
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// input types, and the like, and should not be non-empty in
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// between items
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assert!(self.lifetimes_to_define.is_empty());
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let res = f(self);
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assert!(self.in_scope_lifetimes.is_empty());
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self.in_scope_lifetimes = old_in_scope_lifetimes;
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res
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}
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pub(super) fn lower_mod(&mut self, items: &[P<Item>], inner: Span) -> hir::Mod<'hir> {
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hir::Mod {
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inner,
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item_ids: self.arena.alloc_from_iter(items.iter().flat_map(|x| self.lower_item_id(x))),
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}
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}
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pub(super) fn lower_item_id(&mut self, i: &Item) -> SmallVec<[hir::ItemId; 1]> {
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let node_ids = match i.kind {
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ItemKind::Use(ref use_tree) => {
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let mut vec = smallvec![i.id];
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self.lower_item_id_use_tree(use_tree, i.id, &mut vec);
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vec
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}
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ItemKind::MacroDef(..) => SmallVec::new(),
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ItemKind::Fn(..) | ItemKind::Impl(box ImplKind { of_trait: None, .. }) => {
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smallvec![i.id]
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}
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_ => smallvec![i.id],
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};
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node_ids
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.into_iter()
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.map(|node_id| hir::ItemId {
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def_id: self.allocate_hir_id_counter(node_id).expect_owner(),
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})
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.collect()
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}
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fn lower_item_id_use_tree(
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&mut self,
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tree: &UseTree,
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base_id: NodeId,
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vec: &mut SmallVec<[NodeId; 1]>,
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) {
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match tree.kind {
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UseTreeKind::Nested(ref nested_vec) => {
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for &(ref nested, id) in nested_vec {
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vec.push(id);
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self.lower_item_id_use_tree(nested, id, vec);
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}
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}
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UseTreeKind::Glob => {}
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UseTreeKind::Simple(_, id1, id2) => {
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for (_, &id) in
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iter::zip(self.expect_full_res_from_use(base_id).skip(1), &[id1, id2])
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{
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vec.push(id);
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}
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}
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}
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}
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pub fn lower_item(&mut self, i: &Item) -> Option<hir::Item<'hir>> {
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let mut ident = i.ident;
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let mut vis = self.lower_visibility(&i.vis, None);
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if let ItemKind::MacroDef(MacroDef { ref body, macro_rules }) = i.kind {
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if !macro_rules || self.sess.contains_name(&i.attrs, sym::macro_export) {
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let hir_id = self.lower_node_id(i.id);
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self.lower_attrs(hir_id, &i.attrs);
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let body = P(self.lower_mac_args(body));
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self.exported_macros.push(hir::MacroDef {
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ident,
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vis,
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def_id: hir_id.expect_owner(),
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span: i.span,
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ast: MacroDef { body, macro_rules },
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});
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} else {
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for a in i.attrs.iter() {
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let a = self.lower_attr(a);
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self.non_exported_macro_attrs.push(a);
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}
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}
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return None;
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}
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let hir_id = self.lower_node_id(i.id);
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let attrs = self.lower_attrs(hir_id, &i.attrs);
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let kind = self.lower_item_kind(i.span, i.id, hir_id, &mut ident, attrs, &mut vis, &i.kind);
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Some(hir::Item { def_id: hir_id.expect_owner(), ident, kind, vis, span: i.span })
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}
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fn lower_item_kind(
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&mut self,
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span: Span,
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id: NodeId,
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hir_id: hir::HirId,
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ident: &mut Ident,
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attrs: Option<&'hir [Attribute]>,
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vis: &mut hir::Visibility<'hir>,
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i: &ItemKind,
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) -> hir::ItemKind<'hir> {
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match *i {
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ItemKind::ExternCrate(orig_name) => hir::ItemKind::ExternCrate(orig_name),
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ItemKind::Use(ref use_tree) => {
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// Start with an empty prefix.
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let prefix = Path { segments: vec![], span: use_tree.span, tokens: None };
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self.lower_use_tree(use_tree, &prefix, id, vis, ident, attrs)
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}
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ItemKind::Static(ref t, m, ref e) => {
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let (ty, body_id) = self.lower_const_item(t, span, e.as_deref());
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hir::ItemKind::Static(ty, m, body_id)
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}
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ItemKind::Const(_, ref t, ref e) => {
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let (ty, body_id) = self.lower_const_item(t, span, e.as_deref());
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hir::ItemKind::Const(ty, body_id)
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}
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ItemKind::Fn(box FnKind(
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_,
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FnSig { ref decl, header, span: fn_sig_span },
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ref generics,
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ref body,
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)) => {
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let fn_def_id = self.resolver.local_def_id(id);
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self.with_new_scopes(|this| {
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this.current_item = Some(ident.span);
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// Note: we don't need to change the return type from `T` to
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// `impl Future<Output = T>` here because lower_body
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// only cares about the input argument patterns in the function
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// declaration (decl), not the return types.
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let asyncness = header.asyncness;
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let body_id =
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this.lower_maybe_async_body(span, &decl, asyncness, body.as_deref());
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let (generics, decl) = this.add_in_band_defs(
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generics,
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fn_def_id,
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AnonymousLifetimeMode::PassThrough,
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|this, idty| {
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let ret_id = asyncness.opt_return_id();
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this.lower_fn_decl(
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&decl,
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Some((fn_def_id.to_def_id(), idty)),
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true,
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ret_id,
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)
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},
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);
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let sig = hir::FnSig {
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decl,
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header: this.lower_fn_header(header, fn_sig_span, id),
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span: fn_sig_span,
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};
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hir::ItemKind::Fn(sig, generics, body_id)
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})
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}
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ItemKind::Mod(_, ref mod_kind) => match mod_kind {
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ModKind::Loaded(items, _, inner_span) => {
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hir::ItemKind::Mod(self.lower_mod(items, *inner_span))
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}
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ModKind::Unloaded => panic!("`mod` items should have been loaded by now"),
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},
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ItemKind::ForeignMod(ref fm) => {
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if fm.abi.is_none() {
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self.maybe_lint_missing_abi(span, id, abi::Abi::C { unwind: false });
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}
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hir::ItemKind::ForeignMod {
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abi: fm.abi.map_or(abi::Abi::C { unwind: false }, |abi| self.lower_abi(abi)),
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items: self
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.arena
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.alloc_from_iter(fm.items.iter().map(|x| self.lower_foreign_item_ref(x))),
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}
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}
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ItemKind::GlobalAsm(ref ga) => hir::ItemKind::GlobalAsm(self.lower_global_asm(ga)),
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ItemKind::TyAlias(box TyAliasKind(_, ref gen, _, Some(ref ty))) => {
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// We lower
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//
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// type Foo = impl Trait
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//
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// to
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//
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// type Foo = Foo1
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// opaque type Foo1: Trait
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let ty = self.lower_ty(
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ty,
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ImplTraitContext::OtherOpaqueTy {
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capturable_lifetimes: &mut FxHashSet::default(),
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origin: hir::OpaqueTyOrigin::TyAlias,
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},
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);
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let generics = self.lower_generics(gen, ImplTraitContext::disallowed());
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hir::ItemKind::TyAlias(ty, generics)
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}
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ItemKind::TyAlias(box TyAliasKind(_, ref generics, _, None)) => {
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let ty = self.arena.alloc(self.ty(span, hir::TyKind::Err));
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let generics = self.lower_generics(generics, ImplTraitContext::disallowed());
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hir::ItemKind::TyAlias(ty, generics)
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}
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ItemKind::Enum(ref enum_definition, ref generics) => hir::ItemKind::Enum(
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hir::EnumDef {
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variants: self.arena.alloc_from_iter(
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enum_definition.variants.iter().map(|x| self.lower_variant(x)),
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),
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},
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self.lower_generics(generics, ImplTraitContext::disallowed()),
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),
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ItemKind::Struct(ref struct_def, ref generics) => {
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let struct_def = self.lower_variant_data(hir_id, struct_def);
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hir::ItemKind::Struct(
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struct_def,
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self.lower_generics(generics, ImplTraitContext::disallowed()),
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)
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}
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ItemKind::Union(ref vdata, ref generics) => {
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let vdata = self.lower_variant_data(hir_id, vdata);
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hir::ItemKind::Union(
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vdata,
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self.lower_generics(generics, ImplTraitContext::disallowed()),
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)
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}
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ItemKind::Impl(box ImplKind {
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unsafety,
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polarity,
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defaultness,
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constness,
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generics: ref ast_generics,
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of_trait: ref trait_ref,
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self_ty: ref ty,
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items: ref impl_items,
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}) => {
|
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// Lower the "impl header" first. This ordering is important
|
|
// for in-band lifetimes! Consider `'a` here:
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//
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|
// impl Foo<'a> for u32 {
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|
// fn method(&'a self) { .. }
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// }
|
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//
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// Because we start by lowering the `Foo<'a> for u32`
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// part, we will add `'a` to the list of generics on
|
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// the impl. When we then encounter it later in the
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// method, it will not be considered an in-band
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// lifetime to be added, but rather a reference to a
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// parent lifetime.
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let lowered_trait_def_id = self.lower_node_id(id).expect_owner();
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let (generics, (trait_ref, lowered_ty)) = self.add_in_band_defs(
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ast_generics,
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lowered_trait_def_id,
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AnonymousLifetimeMode::CreateParameter,
|
|
|this, _| {
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|
let trait_ref = trait_ref.as_ref().map(|trait_ref| {
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this.lower_trait_ref(trait_ref, ImplTraitContext::disallowed())
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});
|
|
|
|
if let Some(ref trait_ref) = trait_ref {
|
|
if let Res::Def(DefKind::Trait, def_id) = trait_ref.path.res {
|
|
this.trait_impls
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|
.entry(def_id)
|
|
.or_default()
|
|
.push(lowered_trait_def_id);
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}
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}
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let lowered_ty = this.lower_ty(ty, ImplTraitContext::disallowed());
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(trait_ref, lowered_ty)
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},
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);
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|
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let new_impl_items =
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self.with_in_scope_lifetime_defs(&ast_generics.params, |this| {
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this.arena.alloc_from_iter(
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impl_items.iter().map(|item| this.lower_impl_item_ref(item)),
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)
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});
|
|
|
|
// `defaultness.has_value()` is never called for an `impl`, always `true` in order
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|
// to not cause an assertion failure inside the `lower_defaultness` function.
|
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let has_val = true;
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let (defaultness, defaultness_span) = self.lower_defaultness(defaultness, has_val);
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|
hir::ItemKind::Impl(hir::Impl {
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unsafety: self.lower_unsafety(unsafety),
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polarity,
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defaultness,
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defaultness_span,
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constness: self.lower_constness(constness),
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generics,
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of_trait: trait_ref,
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self_ty: lowered_ty,
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items: new_impl_items,
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})
|
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}
|
|
ItemKind::Trait(box TraitKind(
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is_auto,
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|
unsafety,
|
|
ref generics,
|
|
ref bounds,
|
|
ref items,
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|
)) => {
|
|
let bounds = self.lower_param_bounds(bounds, ImplTraitContext::disallowed());
|
|
let items = self
|
|
.arena
|
|
.alloc_from_iter(items.iter().map(|item| self.lower_trait_item_ref(item)));
|
|
hir::ItemKind::Trait(
|
|
is_auto,
|
|
self.lower_unsafety(unsafety),
|
|
self.lower_generics(generics, ImplTraitContext::disallowed()),
|
|
bounds,
|
|
items,
|
|
)
|
|
}
|
|
ItemKind::TraitAlias(ref generics, ref bounds) => hir::ItemKind::TraitAlias(
|
|
self.lower_generics(generics, ImplTraitContext::disallowed()),
|
|
self.lower_param_bounds(bounds, ImplTraitContext::disallowed()),
|
|
),
|
|
ItemKind::MacroDef(..) | 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 mut capturable_lifetimes;
|
|
let itctx = if self.sess.features_untracked().impl_trait_in_bindings {
|
|
capturable_lifetimes = FxHashSet::default();
|
|
ImplTraitContext::OtherOpaqueTy {
|
|
capturable_lifetimes: &mut capturable_lifetimes,
|
|
origin: hir::OpaqueTyOrigin::Misc,
|
|
}
|
|
} else {
|
|
ImplTraitContext::Disallowed(ImplTraitPosition::Binding)
|
|
};
|
|
let ty = self.lower_ty(ty, itctx);
|
|
(ty, self.lower_const_body(span, body))
|
|
}
|
|
|
|
fn lower_use_tree(
|
|
&mut self,
|
|
tree: &UseTree,
|
|
prefix: &Path,
|
|
id: NodeId,
|
|
vis: &mut hir::Visibility<'hir>,
|
|
ident: &mut Ident,
|
|
attrs: Option<&'hir [Attribute]>,
|
|
) -> hir::ItemKind<'hir> {
|
|
debug!("lower_use_tree(tree={:?})", tree);
|
|
debug!("lower_use_tree: vis = {:?}", vis);
|
|
|
|
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);
|
|
// 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 (res, &new_node_id) in iter::zip(resolutions, &[id1, id2]) {
|
|
let ident = *ident;
|
|
let mut path = path.clone();
|
|
for seg in &mut path.segments {
|
|
seg.id = self.resolver.next_node_id();
|
|
}
|
|
let span = path.span;
|
|
|
|
self.with_hir_id_owner(new_node_id, |this| {
|
|
let new_id = this.lower_node_id(new_node_id);
|
|
let res = this.lower_res(res);
|
|
let path = this.lower_path_extra(res, &path, ParamMode::Explicit, None);
|
|
let kind = hir::ItemKind::Use(path, hir::UseKind::Single);
|
|
let vis = this.rebuild_vis(&vis);
|
|
if let Some(attrs) = attrs {
|
|
this.attrs.insert(new_id, attrs);
|
|
}
|
|
|
|
this.insert_item(hir::Item {
|
|
def_id: new_id.expect_owner(),
|
|
ident,
|
|
kind,
|
|
vis,
|
|
span,
|
|
});
|
|
});
|
|
}
|
|
|
|
let path = self.lower_path_extra(ret_res, &path, ParamMode::Explicit, None);
|
|
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.lower_node_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.resolver.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 vis = this.rebuild_vis(&vis);
|
|
let mut ident = *ident;
|
|
|
|
let kind =
|
|
this.lower_use_tree(use_tree, &prefix, id, &mut vis, &mut ident, attrs);
|
|
if let Some(attrs) = attrs {
|
|
this.attrs.insert(new_hir_id, attrs);
|
|
}
|
|
|
|
this.insert_item(hir::Item {
|
|
def_id: new_hir_id.expect_owner(),
|
|
ident,
|
|
kind,
|
|
vis,
|
|
span: use_tree.span,
|
|
});
|
|
});
|
|
}
|
|
|
|
// Subtle and a bit hacky: we lower the privacy level
|
|
// of the list stem to "private" most of the time, but
|
|
// not for "restricted" paths. The key thing is that
|
|
// we don't want it to stay as `pub` (with no caveats)
|
|
// because that affects rustdoc and also the lints
|
|
// about `pub` items. But we can't *always* make it
|
|
// private -- particularly not for restricted paths --
|
|
// because it contains node-ids that would then be
|
|
// unused, failing the check that HirIds are "densely
|
|
// assigned".
|
|
match vis.node {
|
|
hir::VisibilityKind::Public
|
|
| hir::VisibilityKind::Crate(_)
|
|
| hir::VisibilityKind::Inherited => {
|
|
*vis = respan(prefix.span.shrink_to_lo(), hir::VisibilityKind::Inherited);
|
|
}
|
|
hir::VisibilityKind::Restricted { .. } => {
|
|
// Do nothing here, as described in the comment on the match.
|
|
}
|
|
}
|
|
|
|
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, None);
|
|
hir::ItemKind::Use(path, hir::UseKind::ListStem)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Paths like the visibility path in `pub(super) use foo::{bar, baz}` are repeated
|
|
/// many times in the HIR tree; for each occurrence, we need to assign distinct
|
|
/// `NodeId`s. (See, e.g., #56128.)
|
|
fn rebuild_use_path(&mut self, path: &hir::Path<'hir>) -> &'hir hir::Path<'hir> {
|
|
debug!("rebuild_use_path(path = {:?})", path);
|
|
let segments =
|
|
self.arena.alloc_from_iter(path.segments.iter().map(|seg| hir::PathSegment {
|
|
ident: seg.ident,
|
|
hir_id: seg.hir_id.map(|_| self.next_id()),
|
|
res: seg.res,
|
|
args: None,
|
|
infer_args: seg.infer_args,
|
|
}));
|
|
self.arena.alloc(hir::Path { span: path.span, res: path.res, segments })
|
|
}
|
|
|
|
fn rebuild_vis(&mut self, vis: &hir::Visibility<'hir>) -> hir::Visibility<'hir> {
|
|
let vis_kind = match vis.node {
|
|
hir::VisibilityKind::Public => hir::VisibilityKind::Public,
|
|
hir::VisibilityKind::Crate(sugar) => hir::VisibilityKind::Crate(sugar),
|
|
hir::VisibilityKind::Inherited => hir::VisibilityKind::Inherited,
|
|
hir::VisibilityKind::Restricted { ref path, hir_id: _ } => {
|
|
hir::VisibilityKind::Restricted {
|
|
path: self.rebuild_use_path(path),
|
|
hir_id: self.next_id(),
|
|
}
|
|
}
|
|
};
|
|
respan(vis.span, vis_kind)
|
|
}
|
|
|
|
fn lower_foreign_item(&mut self, i: &ForeignItem) -> 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);
|
|
hir::ForeignItem {
|
|
def_id,
|
|
ident: i.ident,
|
|
kind: match i.kind {
|
|
ForeignItemKind::Fn(box FnKind(_, ref sig, ref generics, _)) => {
|
|
let fdec = &sig.decl;
|
|
let (generics, (fn_dec, fn_args)) = self.add_in_band_defs(
|
|
generics,
|
|
def_id,
|
|
AnonymousLifetimeMode::PassThrough,
|
|
|this, _| {
|
|
(
|
|
// Disallow `impl Trait` in foreign items.
|
|
this.lower_fn_decl(fdec, None, false, 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());
|
|
hir::ForeignItemKind::Static(ty, m)
|
|
}
|
|
ForeignItemKind::TyAlias(..) => hir::ForeignItemKind::Type,
|
|
ForeignItemKind::MacCall(_) => panic!("macro shouldn't exist here"),
|
|
},
|
|
vis: self.lower_visibility(&i.vis, None),
|
|
span: i.span,
|
|
}
|
|
}
|
|
|
|
fn lower_foreign_item_ref(&mut self, i: &ForeignItem) -> hir::ForeignItemRef<'hir> {
|
|
hir::ForeignItemRef {
|
|
id: hir::ForeignItemId { def_id: self.lower_node_id(i.id).expect_owner() },
|
|
ident: i.ident,
|
|
span: i.span,
|
|
vis: self.lower_visibility(&i.vis, Some(i.id)),
|
|
}
|
|
}
|
|
|
|
fn lower_global_asm(&mut self, ga: &GlobalAsm) -> &'hir hir::GlobalAsm {
|
|
self.arena.alloc(hir::GlobalAsm { asm: ga.asm })
|
|
}
|
|
|
|
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: v.ident,
|
|
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(),
|
|
);
|
|
self.arena.alloc(t)
|
|
} else {
|
|
self.lower_ty(&f.ty, ImplTraitContext::disallowed())
|
|
};
|
|
let hir_id = self.lower_node_id(f.id);
|
|
self.lower_attrs(hir_id, &f.attrs);
|
|
hir::FieldDef {
|
|
span: f.span,
|
|
hir_id,
|
|
ident: match f.ident {
|
|
Some(ident) => ident,
|
|
// FIXME(jseyfried): positional field hygiene.
|
|
None => Ident::new(sym::integer(index), f.span),
|
|
},
|
|
vis: self.lower_visibility(&f.vis, None),
|
|
ty,
|
|
}
|
|
}
|
|
|
|
fn lower_trait_item(&mut self, i: &AssocItem) -> hir::TraitItem<'hir> {
|
|
let hir_id = self.lower_node_id(i.id);
|
|
let trait_item_def_id = hir_id.expect_owner();
|
|
|
|
let (generics, kind) = match i.kind {
|
|
AssocItemKind::Const(_, ref ty, ref default) => {
|
|
let ty = self.lower_ty(ty, ImplTraitContext::disallowed());
|
|
let body = default.as_ref().map(|x| self.lower_const_body(i.span, Some(x)));
|
|
(hir::Generics::empty(), hir::TraitItemKind::Const(ty, body))
|
|
}
|
|
AssocItemKind::Fn(box FnKind(_, ref sig, ref generics, None)) => {
|
|
let names = self.lower_fn_params_to_names(&sig.decl);
|
|
let (generics, sig) =
|
|
self.lower_method_sig(generics, sig, trait_item_def_id, false, None, i.id);
|
|
(generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Required(names)))
|
|
}
|
|
AssocItemKind::Fn(box FnKind(_, ref sig, ref generics, 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,
|
|
trait_item_def_id,
|
|
false,
|
|
asyncness.opt_return_id(),
|
|
i.id,
|
|
);
|
|
(generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Provided(body_id)))
|
|
}
|
|
AssocItemKind::TyAlias(box TyAliasKind(_, ref generics, ref bounds, ref default)) => {
|
|
let ty = default.as_ref().map(|x| self.lower_ty(x, ImplTraitContext::disallowed()));
|
|
let generics = self.lower_generics(generics, ImplTraitContext::disallowed());
|
|
let kind = hir::TraitItemKind::Type(
|
|
self.lower_param_bounds(bounds, ImplTraitContext::disallowed()),
|
|
ty,
|
|
);
|
|
|
|
(generics, kind)
|
|
}
|
|
AssocItemKind::MacCall(..) => panic!("macro item shouldn't exist at this point"),
|
|
};
|
|
|
|
self.lower_attrs(hir_id, &i.attrs);
|
|
hir::TraitItem { def_id: trait_item_def_id, ident: i.ident, generics, kind, span: i.span }
|
|
}
|
|
|
|
fn lower_trait_item_ref(&mut self, i: &AssocItem) -> hir::TraitItemRef {
|
|
let (kind, has_default) = match &i.kind {
|
|
AssocItemKind::Const(_, _, default) => (hir::AssocItemKind::Const, default.is_some()),
|
|
AssocItemKind::TyAlias(box TyAliasKind(_, _, _, default)) => {
|
|
(hir::AssocItemKind::Type, default.is_some())
|
|
}
|
|
AssocItemKind::Fn(box FnKind(_, sig, _, default)) => {
|
|
(hir::AssocItemKind::Fn { has_self: sig.decl.has_self() }, default.is_some())
|
|
}
|
|
AssocItemKind::MacCall(..) => unimplemented!(),
|
|
};
|
|
let id = hir::TraitItemId { def_id: self.lower_node_id(i.id).expect_owner() };
|
|
let defaultness = hir::Defaultness::Default { has_value: has_default };
|
|
hir::TraitItemRef { id, ident: i.ident, span: i.span, defaultness, kind }
|
|
}
|
|
|
|
/// Construct `ExprKind::Err` for the given `span`.
|
|
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::ImplItem<'hir> {
|
|
let impl_item_def_id = self.resolver.local_def_id(i.id);
|
|
|
|
let (generics, kind) = match &i.kind {
|
|
AssocItemKind::Const(_, ty, expr) => {
|
|
let ty = self.lower_ty(ty, ImplTraitContext::disallowed());
|
|
(
|
|
hir::Generics::empty(),
|
|
hir::ImplItemKind::Const(ty, self.lower_const_body(i.span, expr.as_deref())),
|
|
)
|
|
}
|
|
AssocItemKind::Fn(box FnKind(_, 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 impl_trait_return_allow = !self.is_in_trait_impl;
|
|
let (generics, sig) = self.lower_method_sig(
|
|
generics,
|
|
sig,
|
|
impl_item_def_id,
|
|
impl_trait_return_allow,
|
|
asyncness.opt_return_id(),
|
|
i.id,
|
|
);
|
|
|
|
(generics, hir::ImplItemKind::Fn(sig, body_id))
|
|
}
|
|
AssocItemKind::TyAlias(box TyAliasKind(_, generics, _, ty)) => {
|
|
let generics = self.lower_generics(generics, ImplTraitContext::disallowed());
|
|
let kind = match ty {
|
|
None => {
|
|
let ty = self.arena.alloc(self.ty(i.span, hir::TyKind::Err));
|
|
hir::ImplItemKind::TyAlias(ty)
|
|
}
|
|
Some(ty) => {
|
|
let ty = self.lower_ty(
|
|
ty,
|
|
ImplTraitContext::OtherOpaqueTy {
|
|
capturable_lifetimes: &mut FxHashSet::default(),
|
|
origin: hir::OpaqueTyOrigin::TyAlias,
|
|
},
|
|
);
|
|
hir::ImplItemKind::TyAlias(ty)
|
|
}
|
|
};
|
|
(generics, kind)
|
|
}
|
|
AssocItemKind::MacCall(..) => panic!("`TyMac` should have been expanded by now"),
|
|
};
|
|
|
|
// 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 hir_id = self.lower_node_id(i.id);
|
|
self.lower_attrs(hir_id, &i.attrs);
|
|
hir::ImplItem {
|
|
def_id: hir_id.expect_owner(),
|
|
ident: i.ident,
|
|
generics,
|
|
vis: self.lower_visibility(&i.vis, None),
|
|
defaultness,
|
|
kind,
|
|
span: i.span,
|
|
}
|
|
}
|
|
|
|
fn lower_impl_item_ref(&mut self, i: &AssocItem) -> hir::ImplItemRef<'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);
|
|
hir::ImplItemRef {
|
|
id: hir::ImplItemId { def_id: self.lower_node_id(i.id).expect_owner() },
|
|
ident: i.ident,
|
|
span: i.span,
|
|
vis: self.lower_visibility(&i.vis, Some(i.id)),
|
|
defaultness,
|
|
kind: match &i.kind {
|
|
AssocItemKind::Const(..) => hir::AssocItemKind::Const,
|
|
AssocItemKind::TyAlias(..) => hir::AssocItemKind::Type,
|
|
AssocItemKind::Fn(box FnKind(_, sig, ..)) => {
|
|
hir::AssocItemKind::Fn { has_self: sig.decl.has_self() }
|
|
}
|
|
AssocItemKind::MacCall(..) => unimplemented!(),
|
|
},
|
|
}
|
|
}
|
|
|
|
/// If an `explicit_owner` is given, this method allocates the `HirId` in
|
|
/// the address space of that item instead of the item currently being
|
|
/// lowered. This can happen during `lower_impl_item_ref()` where we need to
|
|
/// lower a `Visibility` value although we haven't lowered the owning
|
|
/// `ImplItem` in question yet.
|
|
fn lower_visibility(
|
|
&mut self,
|
|
v: &Visibility,
|
|
explicit_owner: Option<NodeId>,
|
|
) -> hir::Visibility<'hir> {
|
|
let node = match v.kind {
|
|
VisibilityKind::Public => hir::VisibilityKind::Public,
|
|
VisibilityKind::Crate(sugar) => hir::VisibilityKind::Crate(sugar),
|
|
VisibilityKind::Restricted { ref path, id } => {
|
|
debug!("lower_visibility: restricted path id = {:?}", id);
|
|
let lowered_id = if let Some(owner) = explicit_owner {
|
|
self.lower_node_id_with_owner(id, owner)
|
|
} else {
|
|
self.lower_node_id(id)
|
|
};
|
|
let res = self.expect_full_res(id);
|
|
let res = self.lower_res(res);
|
|
hir::VisibilityKind::Restricted {
|
|
path: self.lower_path_extra(res, path, ParamMode::Explicit, explicit_owner),
|
|
hir_id: lowered_id,
|
|
}
|
|
}
|
|
VisibilityKind::Inherited => hir::VisibilityKind::Inherited,
|
|
};
|
|
respan(v.span, node)
|
|
}
|
|
|
|
fn lower_defaultness(
|
|
&self,
|
|
d: Defaultness,
|
|
has_value: bool,
|
|
) -> (hir::Defaultness, Option<Span>) {
|
|
match d {
|
|
Defaultness::Default(sp) => (hir::Defaultness::Default { has_value }, Some(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();
|
|
self.bodies.insert(id, 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, ¶m.attrs);
|
|
hir::Param {
|
|
hir_id,
|
|
pat: self.lower_pat(¶m.pat),
|
|
ty_span: param.ty.span,
|
|
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(¶meter.hir_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: parameter.ty_span,
|
|
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,
|
|
fn_def_id: LocalDefId,
|
|
impl_trait_return_allow: bool,
|
|
is_async: Option<NodeId>,
|
|
id: NodeId,
|
|
) -> (hir::Generics<'hir>, hir::FnSig<'hir>) {
|
|
let header = self.lower_fn_header(sig.header, sig.span, id);
|
|
let (generics, decl) = self.add_in_band_defs(
|
|
generics,
|
|
fn_def_id,
|
|
AnonymousLifetimeMode::PassThrough,
|
|
|this, idty| {
|
|
this.lower_fn_decl(
|
|
&sig.decl,
|
|
Some((fn_def_id.to_def_id(), idty)),
|
|
impl_trait_return_allow,
|
|
is_async,
|
|
)
|
|
},
|
|
);
|
|
(generics, hir::FnSig { header, decl, span: sig.span })
|
|
}
|
|
|
|
fn lower_fn_header(&mut self, h: FnHeader, span: Span, id: NodeId) -> 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, span, id),
|
|
}
|
|
}
|
|
|
|
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, span: Span, id: NodeId) -> abi::Abi {
|
|
match ext {
|
|
Extern::None => abi::Abi::Rust,
|
|
Extern::Implicit => {
|
|
self.maybe_lint_missing_abi(span, id, abi::Abi::C { unwind: false });
|
|
abi::Abi::C { unwind: false }
|
|
}
|
|
Extern::Explicit(abi) => self.lower_abi(abi),
|
|
}
|
|
}
|
|
|
|
fn error_on_invalid_abi(&self, abi: StrLit) {
|
|
struct_span_err!(self.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,
|
|
}
|
|
}
|
|
|
|
pub(super) fn lower_generics_mut(
|
|
&mut self,
|
|
generics: &Generics,
|
|
itctx: ImplTraitContext<'_, 'hir>,
|
|
) -> GenericsCtor<'hir> {
|
|
// Collect `?Trait` bounds in where clause and move them to parameter definitions.
|
|
// FIXME: this could probably be done with less rightward drift. It also looks like two
|
|
// control paths where `report_error` is called are the only paths that advance to after the
|
|
// match statement, so the error reporting could probably just be moved there.
|
|
let mut add_bounds: NodeMap<Vec<_>> = Default::default();
|
|
for pred in &generics.where_clause.predicates {
|
|
if let WherePredicate::BoundPredicate(ref bound_pred) = *pred {
|
|
'next_bound: for bound in &bound_pred.bounds {
|
|
if let GenericBound::Trait(_, TraitBoundModifier::Maybe) = *bound {
|
|
let report_error = |this: &mut Self| {
|
|
this.diagnostic().span_err(
|
|
bound_pred.bounded_ty.span,
|
|
"`?Trait` bounds are only permitted at the \
|
|
point where a type parameter is declared",
|
|
);
|
|
};
|
|
// Check if the where clause type is a plain type parameter.
|
|
match bound_pred.bounded_ty.kind {
|
|
TyKind::Path(None, ref path)
|
|
if path.segments.len() == 1
|
|
&& bound_pred.bound_generic_params.is_empty() =>
|
|
{
|
|
if let Some(Res::Def(DefKind::TyParam, def_id)) = self
|
|
.resolver
|
|
.get_partial_res(bound_pred.bounded_ty.id)
|
|
.map(|d| d.base_res())
|
|
{
|
|
if let Some(def_id) = def_id.as_local() {
|
|
for param in &generics.params {
|
|
if let GenericParamKind::Type { .. } = param.kind {
|
|
if def_id == self.resolver.local_def_id(param.id) {
|
|
add_bounds
|
|
.entry(param.id)
|
|
.or_default()
|
|
.push(bound.clone());
|
|
continue 'next_bound;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
report_error(self)
|
|
}
|
|
_ => report_error(self),
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
GenericsCtor {
|
|
params: self.lower_generic_params_mut(&generics.params, &add_bounds, itctx).collect(),
|
|
where_clause: self.lower_where_clause(&generics.where_clause),
|
|
span: generics.span,
|
|
}
|
|
}
|
|
|
|
pub(super) fn lower_generics(
|
|
&mut self,
|
|
generics: &Generics,
|
|
itctx: ImplTraitContext<'_, 'hir>,
|
|
) -> hir::Generics<'hir> {
|
|
let generics_ctor = self.lower_generics_mut(generics, itctx);
|
|
generics_ctor.into_generics(self.arena)
|
|
}
|
|
|
|
fn lower_where_clause(&mut self, wc: &WhereClause) -> hir::WhereClause<'hir> {
|
|
self.with_anonymous_lifetime_mode(AnonymousLifetimeMode::ReportError, |this| {
|
|
hir::WhereClause {
|
|
predicates: this.arena.alloc_from_iter(
|
|
wc.predicates.iter().map(|predicate| this.lower_where_predicate(predicate)),
|
|
),
|
|
span: wc.span,
|
|
}
|
|
})
|
|
}
|
|
|
|
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,
|
|
}) => {
|
|
self.with_in_scope_lifetime_defs(&bound_generic_params, |this| {
|
|
hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
|
|
bound_generic_params: this.lower_generic_params(
|
|
bound_generic_params,
|
|
&NodeMap::default(),
|
|
ImplTraitContext::disallowed(),
|
|
),
|
|
bounded_ty: this.lower_ty(bounded_ty, ImplTraitContext::disallowed()),
|
|
bounds: this.arena.alloc_from_iter(bounds.iter().filter_map(|bound| {
|
|
match *bound {
|
|
// Ignore `?Trait` bounds.
|
|
// They were copied into type parameters already.
|
|
GenericBound::Trait(_, TraitBoundModifier::Maybe) => None,
|
|
_ => Some(
|
|
this.lower_param_bound(bound, ImplTraitContext::disallowed()),
|
|
),
|
|
}
|
|
})),
|
|
span,
|
|
})
|
|
})
|
|
}
|
|
WherePredicate::RegionPredicate(WhereRegionPredicate {
|
|
ref lifetime,
|
|
ref bounds,
|
|
span,
|
|
}) => hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
|
|
span,
|
|
lifetime: self.lower_lifetime(lifetime),
|
|
bounds: self.lower_param_bounds(bounds, ImplTraitContext::disallowed()),
|
|
}),
|
|
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()),
|
|
rhs_ty: self.lower_ty(rhs_ty, ImplTraitContext::disallowed()),
|
|
span,
|
|
})
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Helper struct for delayed construction of Generics.
|
|
pub(super) struct GenericsCtor<'hir> {
|
|
pub(super) params: SmallVec<[hir::GenericParam<'hir>; 4]>,
|
|
where_clause: hir::WhereClause<'hir>,
|
|
span: Span,
|
|
}
|
|
|
|
impl<'hir> GenericsCtor<'hir> {
|
|
pub(super) fn into_generics(self, arena: &'hir Arena<'hir>) -> hir::Generics<'hir> {
|
|
hir::Generics {
|
|
params: arena.alloc_from_iter(self.params),
|
|
where_clause: self.where_clause,
|
|
span: self.span,
|
|
}
|
|
}
|
|
}
|