| use super::{AnonymousLifetimeMode, LoweringContext, ParamMode}; |
| use super::{ImplTraitContext, ImplTraitPosition}; |
| use crate::Arena; |
| |
| use rustc_ast::ast::*; |
| use rustc_ast::attr; |
| use rustc_ast::node_id::NodeMap; |
| use rustc_ast::ptr::P; |
| use rustc_ast::visit::{self, AssocCtxt, Visitor}; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_errors::struct_span_err; |
| use rustc_hir as hir; |
| use rustc_hir::def::{DefKind, Res}; |
| use rustc_hir::def_id::LocalDefId; |
| use rustc_span::source_map::{respan, DesugaringKind}; |
| use rustc_span::symbol::{kw, sym, Ident}; |
| use rustc_span::Span; |
| use rustc_target::spec::abi; |
| |
| use log::debug; |
| use smallvec::{smallvec, SmallVec}; |
| use std::collections::BTreeSet; |
| |
| pub(super) struct ItemLowerer<'a, 'lowering, 'hir> { |
| pub(super) lctx: &'a mut LoweringContext<'lowering, 'hir>, |
| } |
| |
| impl ItemLowerer<'_, '_, '_> { |
| fn with_trait_impl_ref(&mut self, impl_ref: &Option<TraitRef>, f: impl FnOnce(&mut Self)) { |
| let old = self.lctx.is_in_trait_impl; |
| self.lctx.is_in_trait_impl = if let &None = impl_ref { false } else { true }; |
| f(self); |
| self.lctx.is_in_trait_impl = old; |
| } |
| } |
| |
| impl<'a> Visitor<'a> for ItemLowerer<'a, '_, '_> { |
| fn visit_mod(&mut self, m: &'a Mod, _s: Span, _attrs: &[Attribute], n: NodeId) { |
| let hir_id = self.lctx.lower_node_id(n); |
| |
| self.lctx.modules.insert( |
| hir_id, |
| hir::ModuleItems { |
| items: BTreeSet::new(), |
| trait_items: BTreeSet::new(), |
| impl_items: BTreeSet::new(), |
| }, |
| ); |
| |
| let old = self.lctx.current_module; |
| self.lctx.current_module = hir_id; |
| visit::walk_mod(self, m); |
| self.lctx.current_module = old; |
| } |
| |
| fn visit_item(&mut self, item: &'a Item) { |
| let mut item_hir_id = None; |
| self.lctx.with_hir_id_owner(item.id, |lctx| { |
| lctx.without_in_scope_lifetime_defs(|lctx| { |
| if let Some(hir_item) = lctx.lower_item(item) { |
| item_hir_id = Some(hir_item.hir_id); |
| lctx.insert_item(hir_item); |
| } |
| }) |
| }); |
| |
| if let Some(hir_id) = item_hir_id { |
| self.lctx.with_parent_item_lifetime_defs(hir_id, |this| { |
| let this = &mut ItemLowerer { lctx: this }; |
| if let ItemKind::Impl { ref of_trait, .. } = item.kind { |
| this.with_trait_impl_ref(of_trait, |this| visit::walk_item(this, item)); |
| } else { |
| visit::walk_item(this, item); |
| } |
| }); |
| } |
| } |
| |
| fn visit_assoc_item(&mut self, item: &'a AssocItem, ctxt: AssocCtxt) { |
| self.lctx.with_hir_id_owner(item.id, |lctx| match ctxt { |
| AssocCtxt::Trait => { |
| let hir_item = lctx.lower_trait_item(item); |
| let id = hir::TraitItemId { hir_id: hir_item.hir_id }; |
| lctx.trait_items.insert(id, hir_item); |
| lctx.modules.get_mut(&lctx.current_module).unwrap().trait_items.insert(id); |
| } |
| AssocCtxt::Impl => { |
| let hir_item = lctx.lower_impl_item(item); |
| let id = hir::ImplItemId { hir_id: hir_item.hir_id }; |
| lctx.impl_items.insert(id, hir_item); |
| lctx.modules.get_mut(&lctx.current_module).unwrap().impl_items.insert(id); |
| } |
| }); |
| |
| visit::walk_assoc_item(self, item, ctxt); |
| } |
| } |
| |
| impl<'hir> LoweringContext<'_, 'hir> { |
| // Same as the method above, but accepts `hir::GenericParam`s |
| // instead of `ast::GenericParam`s. |
| // This should only be used with generics that have already had their |
| // in-band lifetimes added. In practice, this means that this function is |
| // only used when lowering a child item of a trait or impl. |
| fn with_parent_item_lifetime_defs<T>( |
| &mut self, |
| parent_hir_id: hir::HirId, |
| f: impl FnOnce(&mut LoweringContext<'_, '_>) -> T, |
| ) -> T { |
| let old_len = self.in_scope_lifetimes.len(); |
| |
| let parent_generics = match self.items.get(&parent_hir_id).unwrap().kind { |
| hir::ItemKind::Impl { ref generics, .. } |
| | hir::ItemKind::Trait(_, _, ref generics, ..) => &generics.params[..], |
| _ => &[], |
| }; |
| let lt_def_names = parent_generics.iter().filter_map(|param| match param.kind { |
| hir::GenericParamKind::Lifetime { .. } => Some(param.name.normalize_to_macros_2_0()), |
| _ => None, |
| }); |
| self.in_scope_lifetimes.extend(lt_def_names); |
| |
| let res = f(self); |
| |
| self.in_scope_lifetimes.truncate(old_len); |
| res |
| } |
| |
| // Clears (and restores) the `in_scope_lifetimes` field. Used when |
| // visiting nested items, which never inherit in-scope lifetimes |
| // from their surrounding environment. |
| fn without_in_scope_lifetime_defs<T>( |
| &mut self, |
| f: impl FnOnce(&mut LoweringContext<'_, '_>) -> T, |
| ) -> T { |
| let old_in_scope_lifetimes = std::mem::replace(&mut self.in_scope_lifetimes, vec![]); |
| |
| // this vector is only used when walking over impl headers, |
| // input types, and the like, and should not be non-empty in |
| // between items |
| assert!(self.lifetimes_to_define.is_empty()); |
| |
| let res = f(self); |
| |
| assert!(self.in_scope_lifetimes.is_empty()); |
| self.in_scope_lifetimes = old_in_scope_lifetimes; |
| |
| res |
| } |
| |
| pub(super) fn lower_mod(&mut self, m: &Mod) -> hir::Mod<'hir> { |
| hir::Mod { |
| inner: m.inner, |
| item_ids: self |
| .arena |
| .alloc_from_iter(m.items.iter().flat_map(|x| self.lower_item_id(x))), |
| } |
| } |
| |
| pub(super) fn lower_item_id(&mut self, i: &Item) -> SmallVec<[hir::ItemId; 1]> { |
| let node_ids = match i.kind { |
| ItemKind::Use(ref use_tree) => { |
| let mut vec = smallvec![i.id]; |
| self.lower_item_id_use_tree(use_tree, i.id, &mut vec); |
| vec |
| } |
| ItemKind::MacroDef(..) => SmallVec::new(), |
| ItemKind::Fn(..) | ItemKind::Impl { of_trait: None, .. } => smallvec![i.id], |
| _ => smallvec![i.id], |
| }; |
| |
| node_ids |
| .into_iter() |
| .map(|node_id| hir::ItemId { id: self.allocate_hir_id_counter(node_id) }) |
| .collect() |
| } |
| |
| fn lower_item_id_use_tree( |
| &mut self, |
| tree: &UseTree, |
| base_id: NodeId, |
| vec: &mut SmallVec<[NodeId; 1]>, |
| ) { |
| match tree.kind { |
| UseTreeKind::Nested(ref nested_vec) => { |
| for &(ref nested, id) in nested_vec { |
| vec.push(id); |
| self.lower_item_id_use_tree(nested, id, vec); |
| } |
| } |
| UseTreeKind::Glob => {} |
| UseTreeKind::Simple(_, id1, id2) => { |
| for (_, &id) in |
| self.expect_full_res_from_use(base_id).skip(1).zip([id1, id2].iter()) |
| { |
| vec.push(id); |
| } |
| } |
| } |
| } |
| |
| pub fn lower_item(&mut self, i: &Item) -> Option<hir::Item<'hir>> { |
| let mut ident = i.ident; |
| let mut vis = self.lower_visibility(&i.vis, None); |
| let attrs = self.lower_attrs(&i.attrs); |
| |
| if let ItemKind::MacroDef(MacroDef { ref body, macro_rules }) = i.kind { |
| if !macro_rules || attr::contains_name(&i.attrs, sym::macro_export) { |
| let hir_id = self.lower_node_id(i.id); |
| let body = P(self.lower_mac_args(body)); |
| self.exported_macros.push(hir::MacroDef { |
| ident, |
| vis, |
| attrs, |
| hir_id, |
| span: i.span, |
| ast: MacroDef { body, macro_rules }, |
| }); |
| } else { |
| self.non_exported_macro_attrs.extend(attrs.iter().cloned()); |
| } |
| return None; |
| } |
| |
| let kind = self.lower_item_kind(i.span, i.id, &mut ident, attrs, &mut vis, &i.kind); |
| |
| Some(hir::Item { hir_id: self.lower_node_id(i.id), ident, attrs, kind, vis, span: i.span }) |
| } |
| |
| fn lower_item_kind( |
| &mut self, |
| span: Span, |
| id: NodeId, |
| ident: &mut Ident, |
| attrs: &'hir [Attribute], |
| vis: &mut hir::Visibility<'hir>, |
| 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 }; |
| |
| self.lower_use_tree(use_tree, &prefix, id, vis, 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(_, FnSig { ref decl, header }, ref generics, ref body) => { |
| let fn_def_id = self.resolver.local_def_id(id); |
| 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 (generics, decl) = this.add_in_band_defs( |
| generics, |
| fn_def_id, |
| AnonymousLifetimeMode::PassThrough, |
| |this, idty| { |
| let ret_id = asyncness.opt_return_id(); |
| this.lower_fn_decl( |
| &decl, |
| Some((fn_def_id.to_def_id(), idty)), |
| true, |
| ret_id, |
| ) |
| }, |
| ); |
| let sig = hir::FnSig { decl, header: this.lower_fn_header(header) }; |
| hir::ItemKind::Fn(sig, generics, body_id) |
| }) |
| } |
| ItemKind::Mod(ref m) => hir::ItemKind::Mod(self.lower_mod(m)), |
| ItemKind::ForeignMod(ref nm) => hir::ItemKind::ForeignMod(self.lower_foreign_mod(nm)), |
| ItemKind::GlobalAsm(ref ga) => hir::ItemKind::GlobalAsm(self.lower_global_asm(ga)), |
| ItemKind::TyAlias(_, ref gen, _, Some(ref ty)) => { |
| // We lower |
| // |
| // type Foo = impl Trait |
| // |
| // to |
| // |
| // type Foo = Foo1 |
| // opaque type Foo1: Trait |
| let ty = self.lower_ty( |
| ty, |
| ImplTraitContext::OtherOpaqueTy { |
| capturable_lifetimes: &mut FxHashSet::default(), |
| origin: hir::OpaqueTyOrigin::Misc, |
| }, |
| ); |
| let generics = self.lower_generics(gen, ImplTraitContext::disallowed()); |
| hir::ItemKind::TyAlias(ty, generics) |
| } |
| ItemKind::TyAlias(_, ref generics, _, None) => { |
| let ty = self.arena.alloc(self.ty(span, hir::TyKind::Err)); |
| let generics = self.lower_generics(generics, ImplTraitContext::disallowed()); |
| hir::ItemKind::TyAlias(ty, generics) |
| } |
| ItemKind::Enum(ref enum_definition, ref generics) => hir::ItemKind::Enum( |
| hir::EnumDef { |
| variants: self.arena.alloc_from_iter( |
| enum_definition.variants.iter().map(|x| self.lower_variant(x)), |
| ), |
| }, |
| self.lower_generics(generics, ImplTraitContext::disallowed()), |
| ), |
| ItemKind::Struct(ref struct_def, ref generics) => { |
| let struct_def = self.lower_variant_data(struct_def); |
| hir::ItemKind::Struct( |
| struct_def, |
| self.lower_generics(generics, ImplTraitContext::disallowed()), |
| ) |
| } |
| ItemKind::Union(ref vdata, ref generics) => { |
| let vdata = self.lower_variant_data(vdata); |
| hir::ItemKind::Union( |
| vdata, |
| self.lower_generics(generics, ImplTraitContext::disallowed()), |
| ) |
| } |
| ItemKind::Impl { |
| unsafety, |
| polarity, |
| defaultness, |
| constness, |
| generics: ref ast_generics, |
| of_trait: ref trait_ref, |
| self_ty: ref ty, |
| items: ref impl_items, |
| } => { |
| let def_id = self.resolver.local_def_id(id); |
| |
| // 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 lowered_trait_impl_id = self.lower_node_id(id); |
| let (generics, (trait_ref, lowered_ty)) = self.add_in_band_defs( |
| ast_generics, |
| def_id, |
| AnonymousLifetimeMode::CreateParameter, |
| |this, _| { |
| let trait_ref = trait_ref.as_ref().map(|trait_ref| { |
| this.lower_trait_ref(trait_ref, ImplTraitContext::disallowed()) |
| }); |
| |
| if let Some(ref trait_ref) = trait_ref { |
| if let Res::Def(DefKind::Trait, def_id) = trait_ref.path.res { |
| this.trait_impls |
| .entry(def_id) |
| .or_default() |
| .push(lowered_trait_impl_id); |
| } |
| } |
| |
| let lowered_ty = this.lower_ty(ty, ImplTraitContext::disallowed()); |
| |
| (trait_ref, lowered_ty) |
| }, |
| ); |
| |
| let new_impl_items = |
| self.with_in_scope_lifetime_defs(&ast_generics.params, |this| { |
| this.arena.alloc_from_iter( |
| impl_items.iter().map(|item| this.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); |
| hir::ItemKind::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(is_auto, unsafety, ref generics, ref bounds, ref items) => { |
| 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: &'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 }; |
| |
| // 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 resolutions.zip([id1, id2].iter()) { |
| 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); |
| |
| this.insert_item(hir::Item { |
| hir_id: new_id, |
| ident, |
| attrs, |
| 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 }, 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) }; |
| |
| // 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); |
| |
| this.insert_item(hir::Item { |
| hir_id: new_hir_id, |
| ident, |
| attrs, |
| 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 def_id = self.resolver.local_def_id(i.id); |
| hir::ForeignItem { |
| hir_id: self.lower_node_id(i.id), |
| ident: i.ident, |
| attrs: self.lower_attrs(&i.attrs), |
| kind: match i.kind { |
| ForeignItemKind::Fn(_, 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_mod(&mut self, fm: &ForeignMod) -> hir::ForeignMod<'hir> { |
| hir::ForeignMod { |
| abi: fm.abi.map_or(abi::Abi::C, |abi| self.lower_abi(abi)), |
| items: self.arena.alloc_from_iter(fm.items.iter().map(|x| self.lower_foreign_item(x))), |
| } |
| } |
| |
| 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> { |
| hir::Variant { |
| attrs: self.lower_attrs(&v.attrs), |
| data: self.lower_variant_data(&v.data), |
| disr_expr: v.disr_expr.as_ref().map(|e| self.lower_anon_const(e)), |
| id: self.lower_node_id(v.id), |
| ident: v.ident, |
| span: v.span, |
| } |
| } |
| |
| fn lower_variant_data(&mut self, 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_struct_field(f))), |
| recovered, |
| ), |
| VariantData::Tuple(ref fields, id) => hir::VariantData::Tuple( |
| self.arena |
| .alloc_from_iter(fields.iter().enumerate().map(|f| self.lower_struct_field(f))), |
| self.lower_node_id(id), |
| ), |
| VariantData::Unit(id) => hir::VariantData::Unit(self.lower_node_id(id)), |
| } |
| } |
| |
| fn lower_struct_field(&mut self, (index, f): (usize, &StructField)) -> hir::StructField<'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()) |
| }; |
| hir::StructField { |
| span: f.span, |
| hir_id: self.lower_node_id(f.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, |
| attrs: self.lower_attrs(&f.attrs), |
| } |
| } |
| |
| fn lower_trait_item(&mut self, i: &AssocItem) -> hir::TraitItem<'hir> { |
| let trait_item_def_id = self.resolver.local_def_id(i.id); |
| |
| 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(_, 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); |
| (generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Required(names))) |
| } |
| AssocItemKind::Fn(_, ref sig, ref generics, Some(ref body)) => { |
| let body_id = self.lower_fn_body_block(i.span, &sig.decl, Some(body)); |
| let (generics, sig) = |
| self.lower_method_sig(generics, sig, trait_item_def_id, false, None); |
| (generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Provided(body_id))) |
| } |
| AssocItemKind::TyAlias(_, 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"), |
| }; |
| |
| hir::TraitItem { |
| hir_id: self.lower_node_id(i.id), |
| ident: i.ident, |
| attrs: self.lower_attrs(&i.attrs), |
| 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(_, _, _, default) => { |
| (hir::AssocItemKind::Type, default.is_some()) |
| } |
| AssocItemKind::Fn(_, sig, _, default) => { |
| (hir::AssocItemKind::Fn { has_self: sig.decl.has_self() }, default.is_some()) |
| } |
| AssocItemKind::MacCall(..) => unimplemented!(), |
| }; |
| let id = hir::TraitItemId { hir_id: self.lower_node_id(i.id) }; |
| 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(_, 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(), |
| ); |
| |
| (generics, hir::ImplItemKind::Fn(sig, body_id)) |
| } |
| AssocItemKind::TyAlias(_, 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::Misc, |
| }, |
| ); |
| 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); |
| hir::ImplItem { |
| hir_id: self.lower_node_id(i.id), |
| ident: i.ident, |
| attrs: self.lower_attrs(&i.attrs), |
| 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 { hir_id: self.lower_node_id(i.id) }, |
| 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(_, 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.node { |
| 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> { |
| hir::Param { |
| attrs: self.lower_attrs(¶m.attrs), |
| hir_id: self.lower_node_id(param.id), |
| pat: self.lower_pat(¶m.pat), |
| 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, _, ident, _) => { |
| (ident, true) |
| } |
| _ => { |
| // 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 mut stmt_attrs = AttrVec::new(); |
| stmt_attrs.extend(parameter.attrs.iter().cloned()); |
| let (new_parameter_pat, new_parameter_id) = this.pat_ident(desugared_span, ident); |
| let new_parameter = hir::Param { |
| attrs: parameter.attrs, |
| hir_id: parameter.hir_id, |
| pat: new_parameter_pat, |
| 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( |
| AttrVec::new(), |
| 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>, |
| ) -> (hir::Generics<'hir>, hir::FnSig<'hir>) { |
| let header = self.lower_fn_header(sig.header); |
| 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 }) |
| } |
| |
| 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::C, |
| 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, |
| } |
| } |
| } |
