1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Lowers the AST to the HIR.
13 //! Since the AST and HIR are fairly similar, this is mostly a simple procedure,
14 //! much like a fold. Where lowering involves a bit more work things get more
15 //! interesting and there are some invariants you should know about. These mostly
16 //! concern spans and ids.
18 //! Spans are assigned to AST nodes during parsing and then are modified during
19 //! expansion to indicate the origin of a node and the process it went through
20 //! being expanded. Ids are assigned to AST nodes just before lowering.
22 //! For the simpler lowering steps, ids and spans should be preserved. Unlike
23 //! expansion we do not preserve the process of lowering in the spans, so spans
24 //! should not be modified here. When creating a new node (as opposed to
25 //! 'folding' an existing one), then you create a new id using `next_id()`.
27 //! You must ensure that ids are unique. That means that you should only use the
28 //! id from an AST node in a single HIR node (you can assume that AST node ids
29 //! are unique). Every new node must have a unique id. Avoid cloning HIR nodes.
30 //! If you do, you must then set the new node's id to a fresh one.
32 //! Spans are used for error messages and for tools to map semantics back to
33 //! source code. It is therefore not as important with spans as ids to be strict
34 //! about use (you can't break the compiler by screwing up a span). Obviously, a
35 //! HIR node can only have a single span. But multiple nodes can have the same
36 //! span and spans don't need to be kept in order, etc. Where code is preserved
37 //! by lowering, it should have the same span as in the AST. Where HIR nodes are
38 //! new it is probably best to give a span for the whole AST node being lowered.
39 //! All nodes should have real spans, don't use dummy spans. Tools are likely to
40 //! get confused if the spans from leaf AST nodes occur in multiple places
41 //! in the HIR, especially for multiple identifiers.
43 use dep_graph::DepGraph;
45 use hir::map::{Definitions, DefKey};
46 use hir::def_id::{DefIndex, DefId, CRATE_DEF_INDEX};
47 use hir::def::{Def, PathResolution};
48 use lint::builtin::PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES;
49 use middle::cstore::CrateStore;
50 use rustc_data_structures::indexed_vec::IndexVec;
52 use util::common::FN_OUTPUT_NAME;
53 use util::nodemap::{DefIdMap, FxHashMap, NodeMap};
55 use std::collections::BTreeMap;
62 use syntax::ext::hygiene::{Mark, SyntaxContext};
64 use syntax::codemap::{self, respan, Spanned, CompilerDesugaringKind};
65 use syntax::std_inject;
66 use syntax::symbol::{Symbol, keywords};
67 use syntax::tokenstream::{TokenStream, TokenTree, Delimited};
68 use syntax::parse::token::Token;
69 use syntax::util::small_vector::SmallVector;
70 use syntax::visit::{self, Visitor};
73 const HIR_ID_COUNTER_LOCKED: u32 = 0xFFFFFFFF;
75 pub struct LoweringContext<'a> {
76 crate_root: Option<&'static str>,
78 // Use to assign ids to hir nodes that do not directly correspond to an ast node
81 cstore: &'a CrateStore,
83 // As we walk the AST we must keep track of the current 'parent' def id (in
84 // the form of a DefIndex) so that if we create a new node which introduces
85 // a definition, then we can properly create the def id.
86 parent_def: Option<DefIndex>,
87 resolver: &'a mut Resolver,
88 name_map: FxHashMap<Ident, Name>,
90 /// The items being lowered are collected here.
91 items: BTreeMap<NodeId, hir::Item>,
93 trait_items: BTreeMap<hir::TraitItemId, hir::TraitItem>,
94 impl_items: BTreeMap<hir::ImplItemId, hir::ImplItem>,
95 bodies: BTreeMap<hir::BodyId, hir::Body>,
96 exported_macros: Vec<hir::MacroDef>,
98 trait_impls: BTreeMap<DefId, Vec<NodeId>>,
99 trait_default_impl: BTreeMap<DefId, NodeId>,
103 catch_scopes: Vec<NodeId>,
104 loop_scopes: Vec<NodeId>,
105 is_in_loop_condition: bool,
107 type_def_lifetime_params: DefIdMap<usize>,
109 current_hir_id_owner: Vec<(DefIndex, u32)>,
110 item_local_id_counters: NodeMap<u32>,
111 node_id_to_hir_id: IndexVec<NodeId, hir::HirId>,
115 /// Resolve a hir path generated by the lowerer when expanding `for`, `if let`, etc.
116 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool);
118 /// Obtain the resolution for a node id
119 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution>;
121 /// We must keep the set of definitions up to date as we add nodes that weren't in the AST.
122 /// This should only return `None` during testing.
123 fn definitions(&mut self) -> &mut Definitions;
126 pub fn lower_crate(sess: &Session,
128 dep_graph: &DepGraph,
130 resolver: &mut Resolver)
132 // We're constructing the HIR here; we don't care what we will
133 // read, since we haven't even constructed the *input* to
135 let _ignore = dep_graph.in_ignore();
138 crate_root: std_inject::injected_crate_name(krate),
143 name_map: FxHashMap(),
144 items: BTreeMap::new(),
145 trait_items: BTreeMap::new(),
146 impl_items: BTreeMap::new(),
147 bodies: BTreeMap::new(),
148 trait_impls: BTreeMap::new(),
149 trait_default_impl: BTreeMap::new(),
150 exported_macros: Vec::new(),
151 catch_scopes: Vec::new(),
152 loop_scopes: Vec::new(),
153 is_in_loop_condition: false,
154 type_def_lifetime_params: DefIdMap(),
155 current_hir_id_owner: vec![(CRATE_DEF_INDEX, 0)],
156 item_local_id_counters: NodeMap(),
157 node_id_to_hir_id: IndexVec::new(),
162 #[derive(Copy, Clone, PartialEq, Eq)]
164 /// Any path in a type context.
166 /// The `module::Type` in `module::Type::method` in an expression.
170 struct LoweredNodeId {
175 enum ParenthesizedGenericArgs {
181 impl<'a> LoweringContext<'a> {
182 fn lower_crate(mut self, c: &Crate) -> hir::Crate {
183 /// Full-crate AST visitor that inserts into a fresh
184 /// `LoweringContext` any information that may be
185 /// needed from arbitrary locations in the crate.
186 /// E.g. The number of lifetime generic parameters
187 /// declared for every type and trait definition.
188 struct MiscCollector<'lcx, 'interner: 'lcx> {
189 lctx: &'lcx mut LoweringContext<'interner>,
192 impl<'lcx, 'interner> Visitor<'lcx> for MiscCollector<'lcx, 'interner> {
193 fn visit_item(&mut self, item: &'lcx Item) {
194 self.lctx.allocate_hir_id_counter(item.id, item);
197 ItemKind::Struct(_, ref generics) |
198 ItemKind::Union(_, ref generics) |
199 ItemKind::Enum(_, ref generics) |
200 ItemKind::Ty(_, ref generics) |
201 ItemKind::Trait(_, ref generics, ..) => {
202 let def_id = self.lctx.resolver.definitions().local_def_id(item.id);
203 let count = generics.lifetimes.len();
204 self.lctx.type_def_lifetime_params.insert(def_id, count);
208 visit::walk_item(self, item);
211 fn visit_trait_item(&mut self, item: &'lcx TraitItem) {
212 self.lctx.allocate_hir_id_counter(item.id, item);
213 visit::walk_trait_item(self, item);
216 fn visit_impl_item(&mut self, item: &'lcx ImplItem) {
217 self.lctx.allocate_hir_id_counter(item.id, item);
218 visit::walk_impl_item(self, item);
222 struct ItemLowerer<'lcx, 'interner: 'lcx> {
223 lctx: &'lcx mut LoweringContext<'interner>,
226 impl<'lcx, 'interner> Visitor<'lcx> for ItemLowerer<'lcx, 'interner> {
227 fn visit_item(&mut self, item: &'lcx Item) {
228 let mut item_lowered = true;
229 self.lctx.with_hir_id_owner(item.id, |lctx| {
230 if let Some(hir_item) = lctx.lower_item(item) {
231 lctx.items.insert(item.id, hir_item);
233 item_lowered = false;
238 visit::walk_item(self, item);
242 fn visit_trait_item(&mut self, item: &'lcx TraitItem) {
243 self.lctx.with_hir_id_owner(item.id, |lctx| {
244 let id = hir::TraitItemId { node_id: item.id };
245 let hir_item = lctx.lower_trait_item(item);
246 lctx.trait_items.insert(id, hir_item);
249 visit::walk_trait_item(self, item);
252 fn visit_impl_item(&mut self, item: &'lcx ImplItem) {
253 self.lctx.with_hir_id_owner(item.id, |lctx| {
254 let id = hir::ImplItemId { node_id: item.id };
255 let hir_item = lctx.lower_impl_item(item);
256 lctx.impl_items.insert(id, hir_item);
258 visit::walk_impl_item(self, item);
262 self.lower_node_id(CRATE_NODE_ID);
263 debug_assert!(self.node_id_to_hir_id[CRATE_NODE_ID] == hir::CRATE_HIR_ID);
265 visit::walk_crate(&mut MiscCollector { lctx: &mut self }, c);
266 visit::walk_crate(&mut ItemLowerer { lctx: &mut self }, c);
268 let module = self.lower_mod(&c.module);
269 let attrs = self.lower_attrs(&c.attrs);
270 let body_ids = body_ids(&self.bodies);
274 .init_node_id_to_hir_id_mapping(self.node_id_to_hir_id);
280 exported_macros: hir::HirVec::from(self.exported_macros),
282 trait_items: self.trait_items,
283 impl_items: self.impl_items,
286 trait_impls: self.trait_impls,
287 trait_default_impl: self.trait_default_impl,
291 fn allocate_hir_id_counter<T: Debug>(&mut self,
294 if self.item_local_id_counters.insert(owner, 0).is_some() {
295 bug!("Tried to allocate item_local_id_counter for {:?} twice", debug);
297 // Always allocate the first HirId for the owner itself
298 self.lower_node_id_with_owner(owner, owner);
301 fn lower_node_id_generic<F>(&mut self,
305 where F: FnOnce(&mut Self) -> hir::HirId
307 if ast_node_id == DUMMY_NODE_ID {
308 return LoweredNodeId {
309 node_id: DUMMY_NODE_ID,
310 hir_id: hir::DUMMY_HIR_ID,
314 let min_size = ast_node_id.as_usize() + 1;
316 if min_size > self.node_id_to_hir_id.len() {
317 self.node_id_to_hir_id.resize(min_size, hir::DUMMY_HIR_ID);
320 let existing_hir_id = self.node_id_to_hir_id[ast_node_id];
322 if existing_hir_id == hir::DUMMY_HIR_ID {
323 // Generate a new HirId
324 let hir_id = alloc_hir_id(self);
325 self.node_id_to_hir_id[ast_node_id] = hir_id;
327 node_id: ast_node_id,
332 node_id: ast_node_id,
333 hir_id: existing_hir_id,
338 fn with_hir_id_owner<F>(&mut self, owner: NodeId, f: F)
339 where F: FnOnce(&mut Self)
341 let counter = self.item_local_id_counters
342 .insert(owner, HIR_ID_COUNTER_LOCKED)
344 let def_index = self.resolver.definitions().opt_def_index(owner).unwrap();
345 self.current_hir_id_owner.push((def_index, counter));
347 let (new_def_index, new_counter) = self.current_hir_id_owner.pop().unwrap();
349 debug_assert!(def_index == new_def_index);
350 debug_assert!(new_counter >= counter);
352 let prev = self.item_local_id_counters.insert(owner, new_counter).unwrap();
353 debug_assert!(prev == HIR_ID_COUNTER_LOCKED);
356 /// This method allocates a new HirId for the given NodeId and stores it in
357 /// the LoweringContext's NodeId => HirId map.
358 /// Take care not to call this method if the resulting HirId is then not
359 /// actually used in the HIR, as that would trigger an assertion in the
360 /// HirIdValidator later on, which makes sure that all NodeIds got mapped
361 /// properly. Calling the method twice with the same NodeId is fine though.
362 fn lower_node_id(&mut self, ast_node_id: NodeId) -> LoweredNodeId {
363 self.lower_node_id_generic(ast_node_id, |this| {
364 let &mut (def_index, ref mut local_id_counter) = this.current_hir_id_owner
367 let local_id = *local_id_counter;
368 *local_id_counter += 1;
371 local_id: hir::ItemLocalId(local_id),
376 fn lower_node_id_with_owner(&mut self,
380 self.lower_node_id_generic(ast_node_id, |this| {
381 let local_id_counter = this.item_local_id_counters
384 let local_id = *local_id_counter;
386 // We want to be sure not to modify the counter in the map while it
387 // is also on the stack. Otherwise we'll get lost updates when writing
388 // back from the stack to the map.
389 debug_assert!(local_id != HIR_ID_COUNTER_LOCKED);
391 *local_id_counter += 1;
392 let def_index = this.resolver.definitions().opt_def_index(owner).unwrap();
396 local_id: hir::ItemLocalId(local_id),
401 fn record_body(&mut self, value: hir::Expr, decl: Option<&FnDecl>)
403 let body = hir::Body {
404 arguments: decl.map_or(hir_vec![], |decl| {
405 decl.inputs.iter().map(|x| self.lower_arg(x)).collect()
407 is_generator: self.is_generator,
411 self.bodies.insert(id, body);
415 fn next_id(&mut self) -> LoweredNodeId {
416 self.lower_node_id(self.sess.next_node_id())
419 fn expect_full_def(&mut self, id: NodeId) -> Def {
420 self.resolver.get_resolution(id).map_or(Def::Err, |pr| {
421 if pr.unresolved_segments() != 0 {
422 bug!("path not fully resolved: {:?}", pr);
428 fn diagnostic(&self) -> &errors::Handler {
429 self.sess.diagnostic()
432 fn str_to_ident(&self, s: &'static str) -> Name {
436 fn allow_internal_unstable(&self, reason: CompilerDesugaringKind, span: Span) -> Span
438 let mark = Mark::fresh(Mark::root());
439 mark.set_expn_info(codemap::ExpnInfo {
441 callee: codemap::NameAndSpan {
442 format: codemap::CompilerDesugaring(reason),
444 allow_internal_unstable: true,
445 allow_internal_unsafe: false,
448 span.with_ctxt(SyntaxContext::empty().apply_mark(mark))
451 fn with_catch_scope<T, F>(&mut self, catch_id: NodeId, f: F) -> T
452 where F: FnOnce(&mut LoweringContext) -> T
454 let len = self.catch_scopes.len();
455 self.catch_scopes.push(catch_id);
457 let result = f(self);
458 assert_eq!(len + 1, self.catch_scopes.len(),
459 "catch scopes should be added and removed in stack order");
461 self.catch_scopes.pop().unwrap();
466 fn lower_body<F>(&mut self, decl: Option<&FnDecl>, f: F) -> hir::BodyId
467 where F: FnOnce(&mut LoweringContext) -> hir::Expr
469 let prev = mem::replace(&mut self.is_generator, false);
470 let result = f(self);
471 let r = self.record_body(result, decl);
472 self.is_generator = prev;
476 fn with_loop_scope<T, F>(&mut self, loop_id: NodeId, f: F) -> T
477 where F: FnOnce(&mut LoweringContext) -> T
479 // We're no longer in the base loop's condition; we're in another loop.
480 let was_in_loop_condition = self.is_in_loop_condition;
481 self.is_in_loop_condition = false;
483 let len = self.loop_scopes.len();
484 self.loop_scopes.push(loop_id);
486 let result = f(self);
487 assert_eq!(len + 1, self.loop_scopes.len(),
488 "Loop scopes should be added and removed in stack order");
490 self.loop_scopes.pop().unwrap();
492 self.is_in_loop_condition = was_in_loop_condition;
497 fn with_loop_condition_scope<T, F>(&mut self, f: F) -> T
498 where F: FnOnce(&mut LoweringContext) -> T
500 let was_in_loop_condition = self.is_in_loop_condition;
501 self.is_in_loop_condition = true;
503 let result = f(self);
505 self.is_in_loop_condition = was_in_loop_condition;
510 fn with_new_scopes<T, F>(&mut self, f: F) -> T
511 where F: FnOnce(&mut LoweringContext) -> T
513 let was_in_loop_condition = self.is_in_loop_condition;
514 self.is_in_loop_condition = false;
516 let catch_scopes = mem::replace(&mut self.catch_scopes, Vec::new());
517 let loop_scopes = mem::replace(&mut self.loop_scopes, Vec::new());
518 let result = f(self);
519 self.catch_scopes = catch_scopes;
520 self.loop_scopes = loop_scopes;
522 self.is_in_loop_condition = was_in_loop_condition;
527 fn with_parent_def<T, F>(&mut self, parent_id: NodeId, f: F) -> T
528 where F: FnOnce(&mut LoweringContext) -> T
530 let old_def = self.parent_def;
532 let defs = self.resolver.definitions();
533 Some(defs.opt_def_index(parent_id).unwrap())
536 let result = f(self);
538 self.parent_def = old_def;
542 fn def_key(&mut self, id: DefId) -> DefKey {
544 self.resolver.definitions().def_key(id.index)
546 self.cstore.def_key(id)
550 fn lower_ident(&mut self, ident: Ident) -> Name {
551 let ident = ident.modern();
552 if ident.ctxt == SyntaxContext::empty() {
555 *self.name_map.entry(ident).or_insert_with(|| Symbol::from_ident(ident))
558 fn lower_opt_sp_ident(&mut self, o_id: Option<Spanned<Ident>>) -> Option<Spanned<Name>> {
559 o_id.map(|sp_ident| respan(sp_ident.span, sp_ident.node.name))
562 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Spanned<Ident>)>)
566 Some((id, label_ident)) => {
567 let target = if let Def::Label(loop_id) = self.expect_full_def(id) {
568 hir::LoopIdResult::Ok(self.lower_node_id(loop_id).node_id)
570 hir::LoopIdResult::Err(hir::LoopIdError::UnresolvedLabel)
573 ident: Some(label_ident),
574 target_id: hir::ScopeTarget::Loop(target),
578 let loop_id = self.loop_scopes
580 .map(|innermost_loop_id| *innermost_loop_id);
584 target_id: hir::ScopeTarget::Loop(
585 loop_id.map(|id| Ok(self.lower_node_id(id).node_id))
586 .unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
593 fn lower_attrs(&mut self, attrs: &Vec<Attribute>) -> hir::HirVec<Attribute> {
594 attrs.iter().map(|a| self.lower_attr(a)).collect::<Vec<_>>().into()
597 fn lower_attr(&mut self, attr: &Attribute) -> Attribute {
601 path: attr.path.clone(),
602 tokens: self.lower_token_stream(attr.tokens.clone()),
603 is_sugared_doc: attr.is_sugared_doc,
608 fn lower_token_stream(&mut self, tokens: TokenStream) -> TokenStream {
610 .flat_map(|tree| self.lower_token_tree(tree).into_trees())
614 fn lower_token_tree(&mut self, tree: TokenTree) -> TokenStream {
616 TokenTree::Token(span, token) => {
617 self.lower_token(token, span)
619 TokenTree::Delimited(span, delimited) => {
620 TokenTree::Delimited(span, Delimited {
621 delim: delimited.delim,
622 tts: self.lower_token_stream(delimited.tts.into()).into(),
628 fn lower_token(&mut self, token: Token, span: Span) -> TokenStream {
630 Token::Interpolated(_) => {}
631 other => return TokenTree::Token(span, other).into(),
634 let tts = token.interpolated_to_tokenstream(&self.sess.parse_sess, span);
635 self.lower_token_stream(tts)
638 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm {
640 attrs: self.lower_attrs(&arm.attrs),
641 pats: arm.pats.iter().map(|x| self.lower_pat(x)).collect(),
642 guard: arm.guard.as_ref().map(|ref x| P(self.lower_expr(x))),
643 body: P(self.lower_expr(&arm.body)),
647 fn lower_ty_binding(&mut self, b: &TypeBinding) -> hir::TypeBinding {
649 id: self.lower_node_id(b.id).node_id,
650 name: self.lower_ident(b.ident),
651 ty: self.lower_ty(&b.ty),
656 fn lower_ty(&mut self, t: &Ty) -> P<hir::Ty> {
657 let kind = match t.node {
658 TyKind::Infer => hir::TyInfer,
659 TyKind::Err => hir::TyErr,
660 TyKind::Slice(ref ty) => hir::TySlice(self.lower_ty(ty)),
661 TyKind::Ptr(ref mt) => hir::TyPtr(self.lower_mt(mt)),
662 TyKind::Rptr(ref region, ref mt) => {
663 let span = t.span.with_hi(t.span.lo());
664 let lifetime = match *region {
665 Some(ref lt) => self.lower_lifetime(lt),
666 None => self.elided_lifetime(span)
668 hir::TyRptr(lifetime, self.lower_mt(mt))
670 TyKind::BareFn(ref f) => {
671 hir::TyBareFn(P(hir::BareFnTy {
672 lifetimes: self.lower_lifetime_defs(&f.lifetimes),
673 unsafety: self.lower_unsafety(f.unsafety),
675 decl: self.lower_fn_decl(&f.decl),
676 arg_names: self.lower_fn_args_to_names(&f.decl),
679 TyKind::Never => hir::TyNever,
680 TyKind::Tup(ref tys) => {
681 hir::TyTup(tys.iter().map(|ty| self.lower_ty(ty)).collect())
683 TyKind::Paren(ref ty) => {
684 return self.lower_ty(ty);
686 TyKind::Path(ref qself, ref path) => {
687 let id = self.lower_node_id(t.id);
688 let qpath = self.lower_qpath(t.id, qself, path, ParamMode::Explicit);
689 return self.ty_path(id, t.span, qpath);
691 TyKind::ImplicitSelf => {
692 hir::TyPath(hir::QPath::Resolved(None, P(hir::Path {
693 def: self.expect_full_def(t.id),
695 hir::PathSegment::from_name(keywords::SelfType.name())
700 TyKind::Array(ref ty, ref length) => {
701 let length = self.lower_body(None, |this| this.lower_expr(length));
702 hir::TyArray(self.lower_ty(ty), length)
704 TyKind::Typeof(ref expr) => {
705 let expr = self.lower_body(None, |this| this.lower_expr(expr));
708 TyKind::TraitObject(ref bounds, ..) => {
709 let mut lifetime_bound = None;
710 let bounds = bounds.iter().filter_map(|bound| {
712 TraitTyParamBound(ref ty, TraitBoundModifier::None) => {
713 Some(self.lower_poly_trait_ref(ty))
715 TraitTyParamBound(_, TraitBoundModifier::Maybe) => None,
716 RegionTyParamBound(ref lifetime) => {
717 if lifetime_bound.is_none() {
718 lifetime_bound = Some(self.lower_lifetime(lifetime));
724 let lifetime_bound = lifetime_bound.unwrap_or_else(|| {
725 self.elided_lifetime(t.span)
727 hir::TyTraitObject(bounds, lifetime_bound)
729 TyKind::ImplTrait(ref bounds) => {
730 hir::TyImplTrait(self.lower_bounds(bounds))
732 TyKind::Mac(_) => panic!("TyMac should have been expanded by now."),
735 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(t.id);
744 fn lower_foreign_mod(&mut self, fm: &ForeignMod) -> hir::ForeignMod {
747 items: fm.items.iter().map(|x| self.lower_foreign_item(x)).collect(),
751 fn lower_global_asm(&mut self, ga: &GlobalAsm) -> P<hir::GlobalAsm> {
758 fn lower_variant(&mut self, v: &Variant) -> hir::Variant {
760 node: hir::Variant_ {
761 name: v.node.name.name,
762 attrs: self.lower_attrs(&v.node.attrs),
763 data: self.lower_variant_data(&v.node.data),
764 disr_expr: v.node.disr_expr.as_ref().map(|e| {
765 self.lower_body(None, |this| this.lower_expr(e))
772 fn lower_qpath(&mut self,
774 qself: &Option<QSelf>,
776 param_mode: ParamMode)
778 let qself_position = qself.as_ref().map(|q| q.position);
779 let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty));
781 let resolution = self.resolver.get_resolution(id)
782 .unwrap_or(PathResolution::new(Def::Err));
784 let proj_start = p.segments.len() - resolution.unresolved_segments();
785 let path = P(hir::Path {
786 def: resolution.base_def(),
787 segments: p.segments[..proj_start].iter().enumerate().map(|(i, segment)| {
788 let param_mode = match (qself_position, param_mode) {
789 (Some(j), ParamMode::Optional) if i < j => {
790 // This segment is part of the trait path in a
791 // qualified path - one of `a`, `b` or `Trait`
792 // in `<X as a::b::Trait>::T::U::method`.
798 // Figure out if this is a type/trait segment,
799 // which may need lifetime elision performed.
800 let parent_def_id = |this: &mut Self, def_id: DefId| {
803 index: this.def_key(def_id).parent.expect("missing parent")
806 let type_def_id = match resolution.base_def() {
807 Def::AssociatedTy(def_id) if i + 2 == proj_start => {
808 Some(parent_def_id(self, def_id))
810 Def::Variant(def_id) if i + 1 == proj_start => {
811 Some(parent_def_id(self, def_id))
813 Def::Struct(def_id) |
816 Def::TyAlias(def_id) |
817 Def::Trait(def_id) if i + 1 == proj_start => Some(def_id),
820 let parenthesized_generic_args = match resolution.base_def() {
821 // `a::b::Trait(Args)`
822 Def::Trait(..) if i + 1 == proj_start => ParenthesizedGenericArgs::Ok,
823 // `a::b::Trait(Args)::TraitItem`
825 Def::AssociatedConst(..) |
826 Def::AssociatedTy(..) if i + 2 == proj_start => ParenthesizedGenericArgs::Ok,
827 // Avoid duplicated errors
828 Def::Err => ParenthesizedGenericArgs::Ok,
830 Def::Struct(..) | Def::Enum(..) | Def::Union(..) | Def::TyAlias(..) |
831 Def::Variant(..) if i + 1 == proj_start => ParenthesizedGenericArgs::Err,
832 // A warning for now, for compatibility reasons
833 _ => ParenthesizedGenericArgs::Warn,
836 let num_lifetimes = type_def_id.map_or(0, |def_id| {
837 if let Some(&n) = self.type_def_lifetime_params.get(&def_id) {
840 assert!(!def_id.is_local());
841 let n = self.cstore.item_generics_cloned_untracked(def_id).regions.len();
842 self.type_def_lifetime_params.insert(def_id, n);
845 self.lower_path_segment(p.span, segment, param_mode, num_lifetimes,
846 parenthesized_generic_args)
851 // Simple case, either no projections, or only fully-qualified.
852 // E.g. `std::mem::size_of` or `<I as Iterator>::Item`.
853 if resolution.unresolved_segments() == 0 {
854 return hir::QPath::Resolved(qself, path);
857 // Create the innermost type that we're projecting from.
858 let mut ty = if path.segments.is_empty() {
859 // If the base path is empty that means there exists a
860 // syntactical `Self`, e.g. `&i32` in `<&i32>::clone`.
861 qself.expect("missing QSelf for <T>::...")
863 // Otherwise, the base path is an implicit `Self` type path,
864 // e.g. `Vec` in `Vec::new` or `<I as Iterator>::Item` in
865 // `<I as Iterator>::Item::default`.
866 let new_id = self.next_id();
867 self.ty_path(new_id, p.span, hir::QPath::Resolved(qself, path))
870 // Anything after the base path are associated "extensions",
871 // out of which all but the last one are associated types,
872 // e.g. for `std::vec::Vec::<T>::IntoIter::Item::clone`:
873 // * base path is `std::vec::Vec<T>`
874 // * "extensions" are `IntoIter`, `Item` and `clone`
876 // 1. `std::vec::Vec<T>` (created above)
877 // 2. `<std::vec::Vec<T>>::IntoIter`
878 // 3. `<<std::vec::Vec<T>>::IntoIter>::Item`
879 // * final path is `<<<std::vec::Vec<T>>::IntoIter>::Item>::clone`
880 for (i, segment) in p.segments.iter().enumerate().skip(proj_start) {
881 let segment = P(self.lower_path_segment(p.span, segment, param_mode, 0,
882 ParenthesizedGenericArgs::Warn));
883 let qpath = hir::QPath::TypeRelative(ty, segment);
885 // It's finished, return the extension of the right node type.
886 if i == p.segments.len() - 1 {
890 // Wrap the associated extension in another type node.
891 let new_id = self.next_id();
892 ty = self.ty_path(new_id, p.span, qpath);
895 // Should've returned in the for loop above.
896 span_bug!(p.span, "lower_qpath: no final extension segment in {}..{}",
897 proj_start, p.segments.len())
900 fn lower_path_extra(&mut self,
904 param_mode: ParamMode,
905 defaults_to_global: bool)
907 let mut segments = p.segments.iter();
908 if defaults_to_global && p.is_global() {
913 def: self.expect_full_def(id),
914 segments: segments.map(|segment| {
915 self.lower_path_segment(p.span, segment, param_mode, 0,
916 ParenthesizedGenericArgs::Err)
917 }).chain(name.map(|name| hir::PathSegment::from_name(name)))
923 fn lower_path(&mut self,
926 param_mode: ParamMode,
927 defaults_to_global: bool)
929 self.lower_path_extra(id, p, None, param_mode, defaults_to_global)
932 fn lower_path_segment(&mut self,
934 segment: &PathSegment,
935 param_mode: ParamMode,
936 expected_lifetimes: usize,
937 parenthesized_generic_args: ParenthesizedGenericArgs)
938 -> hir::PathSegment {
939 let (mut parameters, infer_types) = if let Some(ref parameters) = segment.parameters {
940 let msg = "parenthesized parameters may only be used with a trait";
942 PathParameters::AngleBracketed(ref data) => {
943 self.lower_angle_bracketed_parameter_data(data, param_mode)
945 PathParameters::Parenthesized(ref data) => match parenthesized_generic_args {
946 ParenthesizedGenericArgs::Ok => self.lower_parenthesized_parameter_data(data),
947 ParenthesizedGenericArgs::Warn => {
948 self.sess.buffer_lint(PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES,
949 CRATE_NODE_ID, data.span, msg.into());
950 (hir::PathParameters::none(), true)
952 ParenthesizedGenericArgs::Err => {
953 struct_span_err!(self.sess, data.span, E0214, "{}", msg)
954 .span_label(data.span, "only traits may use parentheses").emit();
955 (hir::PathParameters::none(), true)
960 self.lower_angle_bracketed_parameter_data(&Default::default(), param_mode)
963 if !parameters.parenthesized && parameters.lifetimes.is_empty() {
964 parameters.lifetimes = (0..expected_lifetimes).map(|_| {
965 self.elided_lifetime(path_span)
969 hir::PathSegment::new(
970 self.lower_ident(segment.identifier),
976 fn lower_angle_bracketed_parameter_data(&mut self,
977 data: &AngleBracketedParameterData,
978 param_mode: ParamMode)
979 -> (hir::PathParameters, bool) {
980 let &AngleBracketedParameterData { ref lifetimes, ref types, ref bindings, .. } = data;
981 (hir::PathParameters {
982 lifetimes: self.lower_lifetimes(lifetimes),
983 types: types.iter().map(|ty| self.lower_ty(ty)).collect(),
984 bindings: bindings.iter().map(|b| self.lower_ty_binding(b)).collect(),
985 parenthesized: false,
986 }, types.is_empty() && param_mode == ParamMode::Optional)
989 fn lower_parenthesized_parameter_data(&mut self,
990 data: &ParenthesizedParameterData)
991 -> (hir::PathParameters, bool) {
992 let &ParenthesizedParameterData { ref inputs, ref output, span } = data;
993 let inputs = inputs.iter().map(|ty| self.lower_ty(ty)).collect();
994 let mk_tup = |this: &mut Self, tys, span| {
995 let LoweredNodeId { node_id, hir_id } = this.next_id();
996 P(hir::Ty { node: hir::TyTup(tys), id: node_id, hir_id, span })
999 (hir::PathParameters {
1000 lifetimes: hir::HirVec::new(),
1001 types: hir_vec![mk_tup(self, inputs, span)],
1002 bindings: hir_vec![hir::TypeBinding {
1003 id: self.next_id().node_id,
1004 name: Symbol::intern(FN_OUTPUT_NAME),
1005 ty: output.as_ref().map(|ty| self.lower_ty(&ty))
1006 .unwrap_or_else(|| mk_tup(self, hir::HirVec::new(), span)),
1007 span: output.as_ref().map_or(span, |ty| ty.span),
1009 parenthesized: true,
1013 fn lower_local(&mut self, l: &Local) -> P<hir::Local> {
1014 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(l.id);
1018 ty: l.ty.as_ref().map(|t| self.lower_ty(t)),
1019 pat: self.lower_pat(&l.pat),
1020 init: l.init.as_ref().map(|e| P(self.lower_expr(e))),
1022 attrs: l.attrs.clone(),
1023 source: hir::LocalSource::Normal,
1027 fn lower_mutability(&mut self, m: Mutability) -> hir::Mutability {
1029 Mutability::Mutable => hir::MutMutable,
1030 Mutability::Immutable => hir::MutImmutable,
1034 fn lower_arg(&mut self, arg: &Arg) -> hir::Arg {
1035 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(arg.id);
1039 pat: self.lower_pat(&arg.pat),
1043 fn lower_fn_args_to_names(&mut self, decl: &FnDecl)
1044 -> hir::HirVec<Spanned<Name>> {
1045 decl.inputs.iter().map(|arg| {
1046 match arg.pat.node {
1047 PatKind::Ident(_, ident, None) => {
1048 respan(ident.span, ident.node.name)
1050 _ => respan(arg.pat.span, keywords::Invalid.name()),
1055 fn lower_fn_decl(&mut self, decl: &FnDecl) -> P<hir::FnDecl> {
1057 inputs: decl.inputs.iter().map(|arg| self.lower_ty(&arg.ty)).collect(),
1058 output: match decl.output {
1059 FunctionRetTy::Ty(ref ty) => hir::Return(self.lower_ty(ty)),
1060 FunctionRetTy::Default(span) => hir::DefaultReturn(span),
1062 variadic: decl.variadic,
1063 has_implicit_self: decl.inputs.get(0).map_or(false, |arg| {
1065 TyKind::ImplicitSelf => true,
1066 TyKind::Rptr(_, ref mt) => mt.ty.node == TyKind::ImplicitSelf,
1073 fn lower_ty_param_bound(&mut self, tpb: &TyParamBound) -> hir::TyParamBound {
1075 TraitTyParamBound(ref ty, modifier) => {
1076 hir::TraitTyParamBound(self.lower_poly_trait_ref(ty),
1077 self.lower_trait_bound_modifier(modifier))
1079 RegionTyParamBound(ref lifetime) => {
1080 hir::RegionTyParamBound(self.lower_lifetime(lifetime))
1085 fn lower_ty_param(&mut self, tp: &TyParam, add_bounds: &[TyParamBound]) -> hir::TyParam {
1086 let mut name = self.lower_ident(tp.ident);
1088 // Don't expose `Self` (recovered "keyword used as ident" parse error).
1089 // `rustc::ty` expects `Self` to be only used for a trait's `Self`.
1090 // Instead, use gensym("Self") to create a distinct name that looks the same.
1091 if name == keywords::SelfType.name() {
1092 name = Symbol::gensym("Self");
1095 let mut bounds = self.lower_bounds(&tp.bounds);
1096 if !add_bounds.is_empty() {
1097 bounds = bounds.into_iter().chain(self.lower_bounds(add_bounds).into_iter()).collect();
1101 id: self.lower_node_id(tp.id).node_id,
1104 default: tp.default.as_ref().map(|x| self.lower_ty(x)),
1106 pure_wrt_drop: tp.attrs.iter().any(|attr| attr.check_name("may_dangle")),
1107 synthetic: tp.attrs.iter()
1108 .filter(|attr| attr.check_name("rustc_synthetic"))
1109 .map(|_| hir::SyntheticTyParamKind::ImplTrait)
1114 fn lower_ty_params(&mut self, tps: &Vec<TyParam>, add_bounds: &NodeMap<Vec<TyParamBound>>)
1115 -> hir::HirVec<hir::TyParam> {
1116 tps.iter().map(|tp| {
1117 self.lower_ty_param(tp, add_bounds.get(&tp.id).map_or(&[][..], |x| &x))
1121 fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime {
1123 id: self.lower_node_id(l.id).node_id,
1124 name: match self.lower_ident(l.ident) {
1125 x if x == "'_" => hir::LifetimeName::Underscore,
1126 x if x == "'static" => hir::LifetimeName::Static,
1127 name => hir::LifetimeName::Name(name),
1133 fn lower_lifetime_def(&mut self, l: &LifetimeDef) -> hir::LifetimeDef {
1135 lifetime: self.lower_lifetime(&l.lifetime),
1136 bounds: self.lower_lifetimes(&l.bounds),
1137 pure_wrt_drop: l.attrs.iter().any(|attr| attr.check_name("may_dangle")),
1141 fn lower_lifetimes(&mut self, lts: &Vec<Lifetime>) -> hir::HirVec<hir::Lifetime> {
1142 lts.iter().map(|l| self.lower_lifetime(l)).collect()
1145 fn lower_lifetime_defs(&mut self, lts: &Vec<LifetimeDef>) -> hir::HirVec<hir::LifetimeDef> {
1146 lts.iter().map(|l| self.lower_lifetime_def(l)).collect()
1149 fn lower_generics(&mut self, g: &Generics) -> hir::Generics {
1150 // Collect `?Trait` bounds in where clause and move them to parameter definitions.
1151 let mut add_bounds = NodeMap();
1152 for pred in &g.where_clause.predicates {
1153 if let WherePredicate::BoundPredicate(ref bound_pred) = *pred {
1154 'next_bound: for bound in &bound_pred.bounds {
1155 if let TraitTyParamBound(_, TraitBoundModifier::Maybe) = *bound {
1156 let report_error = |this: &mut Self| {
1157 this.diagnostic().span_err(bound_pred.bounded_ty.span,
1158 "`?Trait` bounds are only permitted at the \
1159 point where a type parameter is declared");
1161 // Check if the where clause type is a plain type parameter.
1162 match bound_pred.bounded_ty.node {
1163 TyKind::Path(None, ref path)
1164 if path.segments.len() == 1 &&
1165 bound_pred.bound_lifetimes.is_empty() => {
1166 if let Some(Def::TyParam(def_id)) =
1167 self.resolver.get_resolution(bound_pred.bounded_ty.id)
1168 .map(|d| d.base_def()) {
1169 if let Some(node_id) =
1170 self.resolver.definitions().as_local_node_id(def_id) {
1171 for ty_param in &g.ty_params {
1172 if node_id == ty_param.id {
1173 add_bounds.entry(ty_param.id).or_insert(Vec::new())
1174 .push(bound.clone());
1175 continue 'next_bound;
1182 _ => report_error(self)
1190 ty_params: self.lower_ty_params(&g.ty_params, &add_bounds),
1191 lifetimes: self.lower_lifetime_defs(&g.lifetimes),
1192 where_clause: self.lower_where_clause(&g.where_clause),
1197 fn lower_where_clause(&mut self, wc: &WhereClause) -> hir::WhereClause {
1199 id: self.lower_node_id(wc.id).node_id,
1200 predicates: wc.predicates
1202 .map(|predicate| self.lower_where_predicate(predicate))
1207 fn lower_where_predicate(&mut self, pred: &WherePredicate) -> hir::WherePredicate {
1209 WherePredicate::BoundPredicate(WhereBoundPredicate{ ref bound_lifetimes,
1213 hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
1214 bound_lifetimes: self.lower_lifetime_defs(bound_lifetimes),
1215 bounded_ty: self.lower_ty(bounded_ty),
1216 bounds: bounds.iter().filter_map(|bound| match *bound {
1217 // Ignore `?Trait` bounds, they were copied into type parameters already.
1218 TraitTyParamBound(_, TraitBoundModifier::Maybe) => None,
1219 _ => Some(self.lower_ty_param_bound(bound))
1224 WherePredicate::RegionPredicate(WhereRegionPredicate{ ref lifetime,
1227 hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
1229 lifetime: self.lower_lifetime(lifetime),
1230 bounds: bounds.iter().map(|bound| self.lower_lifetime(bound)).collect(),
1233 WherePredicate::EqPredicate(WhereEqPredicate{ id,
1237 hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
1238 id: self.lower_node_id(id).node_id,
1239 lhs_ty: self.lower_ty(lhs_ty),
1240 rhs_ty: self.lower_ty(rhs_ty),
1247 fn lower_variant_data(&mut self, vdata: &VariantData) -> hir::VariantData {
1249 VariantData::Struct(ref fields, id) => {
1250 hir::VariantData::Struct(fields.iter()
1252 .map(|f| self.lower_struct_field(f))
1254 self.lower_node_id(id).node_id)
1256 VariantData::Tuple(ref fields, id) => {
1257 hir::VariantData::Tuple(fields.iter()
1259 .map(|f| self.lower_struct_field(f))
1261 self.lower_node_id(id).node_id)
1263 VariantData::Unit(id) => hir::VariantData::Unit(self.lower_node_id(id).node_id),
1267 fn lower_trait_ref(&mut self, p: &TraitRef) -> hir::TraitRef {
1268 let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit) {
1269 hir::QPath::Resolved(None, path) => path.and_then(|path| path),
1270 qpath => bug!("lower_trait_ref: unexpected QPath `{:?}`", qpath)
1274 ref_id: self.lower_node_id(p.ref_id).node_id,
1278 fn lower_poly_trait_ref(&mut self, p: &PolyTraitRef) -> hir::PolyTraitRef {
1280 bound_lifetimes: self.lower_lifetime_defs(&p.bound_lifetimes),
1281 trait_ref: self.lower_trait_ref(&p.trait_ref),
1286 fn lower_struct_field(&mut self, (index, f): (usize, &StructField)) -> hir::StructField {
1289 id: self.lower_node_id(f.id).node_id,
1290 name: self.lower_ident(match f.ident {
1291 Some(ident) => ident,
1292 // FIXME(jseyfried) positional field hygiene
1293 None => Ident { name: Symbol::intern(&index.to_string()), ctxt: f.span.ctxt() },
1295 vis: self.lower_visibility(&f.vis, None),
1296 ty: self.lower_ty(&f.ty),
1297 attrs: self.lower_attrs(&f.attrs),
1301 fn lower_field(&mut self, f: &Field) -> hir::Field {
1303 name: respan(f.ident.span, self.lower_ident(f.ident.node)),
1304 expr: P(self.lower_expr(&f.expr)),
1306 is_shorthand: f.is_shorthand,
1310 fn lower_mt(&mut self, mt: &MutTy) -> hir::MutTy {
1312 ty: self.lower_ty(&mt.ty),
1313 mutbl: self.lower_mutability(mt.mutbl),
1317 fn lower_bounds(&mut self, bounds: &[TyParamBound]) -> hir::TyParamBounds {
1318 bounds.iter().map(|bound| self.lower_ty_param_bound(bound)).collect()
1321 fn lower_block(&mut self, b: &Block, targeted_by_break: bool) -> P<hir::Block> {
1322 let mut expr = None;
1324 let mut stmts = vec![];
1326 for (index, stmt) in b.stmts.iter().enumerate() {
1327 if index == b.stmts.len() - 1 {
1328 if let StmtKind::Expr(ref e) = stmt.node {
1329 expr = Some(P(self.lower_expr(e)));
1331 stmts.extend(self.lower_stmt(stmt));
1334 stmts.extend(self.lower_stmt(stmt));
1338 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(b.id);
1343 stmts: stmts.into(),
1345 rules: self.lower_block_check_mode(&b.rules),
1351 fn lower_item_kind(&mut self,
1354 attrs: &hir::HirVec<Attribute>,
1355 vis: &mut hir::Visibility,
1359 ItemKind::ExternCrate(string) => hir::ItemExternCrate(string),
1360 ItemKind::Use(ref view_path) => {
1361 let path = match view_path.node {
1362 ViewPathSimple(_, ref path) => path,
1363 ViewPathGlob(ref path) => path,
1364 ViewPathList(ref path, ref path_list_idents) => {
1365 for &Spanned { node: ref import, span } in path_list_idents {
1366 // `use a::{self as x, b as y};` lowers to
1367 // `use a as x; use a::b as y;`
1368 let mut ident = import.name;
1369 let suffix = if ident.name == keywords::SelfValue.name() {
1370 if let Some(last) = path.segments.last() {
1371 ident = last.identifier;
1378 let mut path = self.lower_path_extra(import.id, path, suffix,
1379 ParamMode::Explicit, true);
1382 self.allocate_hir_id_counter(import.id, import);
1384 node_id: import_node_id,
1385 hir_id: import_hir_id,
1386 } = self.lower_node_id(import.id);
1388 self.with_hir_id_owner(import_node_id, |this| {
1389 let vis = match *vis {
1390 hir::Visibility::Public => hir::Visibility::Public,
1391 hir::Visibility::Crate => hir::Visibility::Crate,
1392 hir::Visibility::Inherited => hir::Visibility::Inherited,
1393 hir::Visibility::Restricted { ref path, id: _ } => {
1394 hir::Visibility::Restricted {
1396 // We are allocating a new NodeId here
1397 id: this.next_id().node_id,
1402 this.items.insert(import_node_id, hir::Item {
1404 hir_id: import_hir_id,
1405 name: import.rename.unwrap_or(ident).name,
1406 attrs: attrs.clone(),
1407 node: hir::ItemUse(P(path), hir::UseKind::Single),
1416 let path = P(self.lower_path(id, path, ParamMode::Explicit, true));
1417 let kind = match view_path.node {
1418 ViewPathSimple(ident, _) => {
1420 hir::UseKind::Single
1422 ViewPathGlob(_) => {
1425 ViewPathList(..) => {
1426 // Privatize the degenerate import base, used only to check
1427 // the stability of `use a::{};`, to avoid it showing up as
1428 // a reexport by accident when `pub`, e.g. in documentation.
1429 *vis = hir::Inherited;
1430 hir::UseKind::ListStem
1433 hir::ItemUse(path, kind)
1435 ItemKind::Static(ref t, m, ref e) => {
1436 let value = self.lower_body(None, |this| this.lower_expr(e));
1437 hir::ItemStatic(self.lower_ty(t),
1438 self.lower_mutability(m),
1441 ItemKind::Const(ref t, ref e) => {
1442 let value = self.lower_body(None, |this| this.lower_expr(e));
1443 hir::ItemConst(self.lower_ty(t), value)
1445 ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => {
1446 self.with_new_scopes(|this| {
1447 let body_id = this.lower_body(Some(decl), |this| {
1448 let body = this.lower_block(body, false);
1449 this.expr_block(body, ThinVec::new())
1451 hir::ItemFn(this.lower_fn_decl(decl),
1452 this.lower_unsafety(unsafety),
1453 this.lower_constness(constness),
1455 this.lower_generics(generics),
1459 ItemKind::Mod(ref m) => hir::ItemMod(self.lower_mod(m)),
1460 ItemKind::ForeignMod(ref nm) => hir::ItemForeignMod(self.lower_foreign_mod(nm)),
1461 ItemKind::GlobalAsm(ref ga) => hir::ItemGlobalAsm(self.lower_global_asm(ga)),
1462 ItemKind::Ty(ref t, ref generics) => {
1463 hir::ItemTy(self.lower_ty(t), self.lower_generics(generics))
1465 ItemKind::Enum(ref enum_definition, ref generics) => {
1466 hir::ItemEnum(hir::EnumDef {
1467 variants: enum_definition.variants
1469 .map(|x| self.lower_variant(x))
1472 self.lower_generics(generics))
1474 ItemKind::Struct(ref struct_def, ref generics) => {
1475 let struct_def = self.lower_variant_data(struct_def);
1476 hir::ItemStruct(struct_def, self.lower_generics(generics))
1478 ItemKind::Union(ref vdata, ref generics) => {
1479 let vdata = self.lower_variant_data(vdata);
1480 hir::ItemUnion(vdata, self.lower_generics(generics))
1482 ItemKind::DefaultImpl(unsafety, ref trait_ref) => {
1483 let trait_ref = self.lower_trait_ref(trait_ref);
1485 if let Def::Trait(def_id) = trait_ref.path.def {
1486 self.trait_default_impl.insert(def_id, id);
1489 hir::ItemDefaultImpl(self.lower_unsafety(unsafety),
1492 ItemKind::Impl(unsafety,
1498 ref impl_items) => {
1499 let new_impl_items = impl_items.iter()
1500 .map(|item| self.lower_impl_item_ref(item))
1502 let ifce = ifce.as_ref().map(|trait_ref| self.lower_trait_ref(trait_ref));
1504 if let Some(ref trait_ref) = ifce {
1505 if let Def::Trait(def_id) = trait_ref.path.def {
1506 self.trait_impls.entry(def_id).or_insert(vec![]).push(id);
1510 hir::ItemImpl(self.lower_unsafety(unsafety),
1511 self.lower_impl_polarity(polarity),
1512 self.lower_defaultness(defaultness, true /* [1] */),
1513 self.lower_generics(generics),
1518 ItemKind::Trait(unsafety, ref generics, ref bounds, ref items) => {
1519 let bounds = self.lower_bounds(bounds);
1520 let items = items.iter().map(|item| self.lower_trait_item_ref(item)).collect();
1521 hir::ItemTrait(self.lower_unsafety(unsafety),
1522 self.lower_generics(generics),
1526 ItemKind::MacroDef(..) | ItemKind::Mac(..) => panic!("Shouldn't still be around"),
1529 // [1] `defaultness.has_value()` is never called for an `impl`, always `true` in order to
1530 // not cause an assertion failure inside the `lower_defaultness` function
1533 fn lower_trait_item(&mut self, i: &TraitItem) -> hir::TraitItem {
1534 self.with_parent_def(i.id, |this| {
1535 let LoweredNodeId { node_id, hir_id } = this.lower_node_id(i.id);
1540 name: this.lower_ident(i.ident),
1541 attrs: this.lower_attrs(&i.attrs),
1542 node: match i.node {
1543 TraitItemKind::Const(ref ty, ref default) => {
1544 hir::TraitItemKind::Const(this.lower_ty(ty),
1545 default.as_ref().map(|x| {
1546 this.lower_body(None, |this| this.lower_expr(x))
1549 TraitItemKind::Method(ref sig, None) => {
1550 let names = this.lower_fn_args_to_names(&sig.decl);
1551 hir::TraitItemKind::Method(this.lower_method_sig(sig),
1552 hir::TraitMethod::Required(names))
1554 TraitItemKind::Method(ref sig, Some(ref body)) => {
1555 let body_id = this.lower_body(Some(&sig.decl), |this| {
1556 let body = this.lower_block(body, false);
1557 this.expr_block(body, ThinVec::new())
1559 hir::TraitItemKind::Method(this.lower_method_sig(sig),
1560 hir::TraitMethod::Provided(body_id))
1562 TraitItemKind::Type(ref bounds, ref default) => {
1563 hir::TraitItemKind::Type(this.lower_bounds(bounds),
1564 default.as_ref().map(|x| this.lower_ty(x)))
1566 TraitItemKind::Macro(..) => panic!("Shouldn't exist any more"),
1573 fn lower_trait_item_ref(&mut self, i: &TraitItem) -> hir::TraitItemRef {
1574 let (kind, has_default) = match i.node {
1575 TraitItemKind::Const(_, ref default) => {
1576 (hir::AssociatedItemKind::Const, default.is_some())
1578 TraitItemKind::Type(_, ref default) => {
1579 (hir::AssociatedItemKind::Type, default.is_some())
1581 TraitItemKind::Method(ref sig, ref default) => {
1582 (hir::AssociatedItemKind::Method {
1583 has_self: sig.decl.has_self(),
1584 }, default.is_some())
1586 TraitItemKind::Macro(..) => unimplemented!(),
1589 id: hir::TraitItemId { node_id: i.id },
1590 name: self.lower_ident(i.ident),
1592 defaultness: self.lower_defaultness(Defaultness::Default, has_default),
1597 fn lower_impl_item(&mut self, i: &ImplItem) -> hir::ImplItem {
1598 self.with_parent_def(i.id, |this| {
1599 let LoweredNodeId { node_id, hir_id } = this.lower_node_id(i.id);
1604 name: this.lower_ident(i.ident),
1605 attrs: this.lower_attrs(&i.attrs),
1606 vis: this.lower_visibility(&i.vis, None),
1607 defaultness: this.lower_defaultness(i.defaultness, true /* [1] */),
1608 node: match i.node {
1609 ImplItemKind::Const(ref ty, ref expr) => {
1610 let body_id = this.lower_body(None, |this| this.lower_expr(expr));
1611 hir::ImplItemKind::Const(this.lower_ty(ty), body_id)
1613 ImplItemKind::Method(ref sig, ref body) => {
1614 let body_id = this.lower_body(Some(&sig.decl), |this| {
1615 let body = this.lower_block(body, false);
1616 this.expr_block(body, ThinVec::new())
1618 hir::ImplItemKind::Method(this.lower_method_sig(sig), body_id)
1620 ImplItemKind::Type(ref ty) => hir::ImplItemKind::Type(this.lower_ty(ty)),
1621 ImplItemKind::Macro(..) => panic!("Shouldn't exist any more"),
1627 // [1] since `default impl` is not yet implemented, this is always true in impls
1630 fn lower_impl_item_ref(&mut self, i: &ImplItem) -> hir::ImplItemRef {
1632 id: hir::ImplItemId { node_id: i.id },
1633 name: self.lower_ident(i.ident),
1635 vis: self.lower_visibility(&i.vis, Some(i.id)),
1636 defaultness: self.lower_defaultness(i.defaultness, true /* [1] */),
1637 kind: match i.node {
1638 ImplItemKind::Const(..) => hir::AssociatedItemKind::Const,
1639 ImplItemKind::Type(..) => hir::AssociatedItemKind::Type,
1640 ImplItemKind::Method(ref sig, _) => hir::AssociatedItemKind::Method {
1641 has_self: sig.decl.has_self(),
1643 ImplItemKind::Macro(..) => unimplemented!(),
1647 // [1] since `default impl` is not yet implemented, this is always true in impls
1650 fn lower_mod(&mut self, m: &Mod) -> hir::Mod {
1653 item_ids: m.items.iter().flat_map(|x| self.lower_item_id(x)).collect(),
1657 fn lower_item_id(&mut self, i: &Item) -> SmallVector<hir::ItemId> {
1659 ItemKind::Use(ref view_path) => {
1660 if let ViewPathList(_, ref imports) = view_path.node {
1661 return iter::once(i.id).chain(imports.iter().map(|import| import.node.id))
1662 .map(|id| hir::ItemId { id: id }).collect();
1665 ItemKind::MacroDef(..) => return SmallVector::new(),
1668 SmallVector::one(hir::ItemId { id: i.id })
1671 pub fn lower_item(&mut self, i: &Item) -> Option<hir::Item> {
1672 let mut name = i.ident.name;
1673 let mut vis = self.lower_visibility(&i.vis, None);
1674 let attrs = self.lower_attrs(&i.attrs);
1675 if let ItemKind::MacroDef(ref def) = i.node {
1676 if !def.legacy || i.attrs.iter().any(|attr| attr.path == "macro_export") {
1677 let body = self.lower_token_stream(def.stream());
1678 self.exported_macros.push(hir::MacroDef {
1691 let node = self.with_parent_def(i.id, |this| {
1692 this.lower_item_kind(i.id, &mut name, &attrs, &mut vis, &i.node)
1695 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(i.id);
1708 fn lower_foreign_item(&mut self, i: &ForeignItem) -> hir::ForeignItem {
1709 self.with_parent_def(i.id, |this| {
1711 id: this.lower_node_id(i.id).node_id,
1713 attrs: this.lower_attrs(&i.attrs),
1714 node: match i.node {
1715 ForeignItemKind::Fn(ref fdec, ref generics) => {
1716 hir::ForeignItemFn(this.lower_fn_decl(fdec),
1717 this.lower_fn_args_to_names(fdec),
1718 this.lower_generics(generics))
1720 ForeignItemKind::Static(ref t, m) => {
1721 hir::ForeignItemStatic(this.lower_ty(t), m)
1724 vis: this.lower_visibility(&i.vis, None),
1730 fn lower_method_sig(&mut self, sig: &MethodSig) -> hir::MethodSig {
1732 generics: self.lower_generics(&sig.generics),
1734 unsafety: self.lower_unsafety(sig.unsafety),
1735 constness: self.lower_constness(sig.constness),
1736 decl: self.lower_fn_decl(&sig.decl),
1740 fn lower_unsafety(&mut self, u: Unsafety) -> hir::Unsafety {
1742 Unsafety::Unsafe => hir::Unsafety::Unsafe,
1743 Unsafety::Normal => hir::Unsafety::Normal,
1747 fn lower_constness(&mut self, c: Spanned<Constness>) -> hir::Constness {
1749 Constness::Const => hir::Constness::Const,
1750 Constness::NotConst => hir::Constness::NotConst,
1754 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
1756 UnOp::Deref => hir::UnDeref,
1757 UnOp::Not => hir::UnNot,
1758 UnOp::Neg => hir::UnNeg,
1762 fn lower_binop(&mut self, b: BinOp) -> hir::BinOp {
1764 node: match b.node {
1765 BinOpKind::Add => hir::BiAdd,
1766 BinOpKind::Sub => hir::BiSub,
1767 BinOpKind::Mul => hir::BiMul,
1768 BinOpKind::Div => hir::BiDiv,
1769 BinOpKind::Rem => hir::BiRem,
1770 BinOpKind::And => hir::BiAnd,
1771 BinOpKind::Or => hir::BiOr,
1772 BinOpKind::BitXor => hir::BiBitXor,
1773 BinOpKind::BitAnd => hir::BiBitAnd,
1774 BinOpKind::BitOr => hir::BiBitOr,
1775 BinOpKind::Shl => hir::BiShl,
1776 BinOpKind::Shr => hir::BiShr,
1777 BinOpKind::Eq => hir::BiEq,
1778 BinOpKind::Lt => hir::BiLt,
1779 BinOpKind::Le => hir::BiLe,
1780 BinOpKind::Ne => hir::BiNe,
1781 BinOpKind::Ge => hir::BiGe,
1782 BinOpKind::Gt => hir::BiGt,
1788 fn lower_pat(&mut self, p: &Pat) -> P<hir::Pat> {
1789 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(p.id);
1794 node: match p.node {
1795 PatKind::Wild => hir::PatKind::Wild,
1796 PatKind::Ident(ref binding_mode, pth1, ref sub) => {
1797 match self.resolver.get_resolution(p.id).map(|d| d.base_def()) {
1798 // `None` can occur in body-less function signatures
1799 def @ None | def @ Some(Def::Local(_)) => {
1800 let canonical_id = match def {
1801 Some(Def::Local(id)) => id,
1804 hir::PatKind::Binding(self.lower_binding_mode(binding_mode),
1806 respan(pth1.span, pth1.node.name),
1807 sub.as_ref().map(|x| self.lower_pat(x)))
1810 hir::PatKind::Path(hir::QPath::Resolved(None, P(hir::Path {
1814 hir::PathSegment::from_name(pth1.node.name)
1820 PatKind::Lit(ref e) => hir::PatKind::Lit(P(self.lower_expr(e))),
1821 PatKind::TupleStruct(ref path, ref pats, ddpos) => {
1822 let qpath = self.lower_qpath(p.id, &None, path, ParamMode::Optional);
1823 hir::PatKind::TupleStruct(qpath,
1824 pats.iter().map(|x| self.lower_pat(x)).collect(),
1827 PatKind::Path(ref qself, ref path) => {
1828 hir::PatKind::Path(self.lower_qpath(p.id, qself, path, ParamMode::Optional))
1830 PatKind::Struct(ref path, ref fields, etc) => {
1831 let qpath = self.lower_qpath(p.id, &None, path, ParamMode::Optional);
1833 let fs = fields.iter()
1837 node: hir::FieldPat {
1838 name: self.lower_ident(f.node.ident),
1839 pat: self.lower_pat(&f.node.pat),
1840 is_shorthand: f.node.is_shorthand,
1845 hir::PatKind::Struct(qpath, fs, etc)
1847 PatKind::Tuple(ref elts, ddpos) => {
1848 hir::PatKind::Tuple(elts.iter().map(|x| self.lower_pat(x)).collect(), ddpos)
1850 PatKind::Box(ref inner) => hir::PatKind::Box(self.lower_pat(inner)),
1851 PatKind::Ref(ref inner, mutbl) => {
1852 hir::PatKind::Ref(self.lower_pat(inner), self.lower_mutability(mutbl))
1854 PatKind::Range(ref e1, ref e2, ref end) => {
1855 hir::PatKind::Range(P(self.lower_expr(e1)),
1856 P(self.lower_expr(e2)),
1857 self.lower_range_end(end))
1859 PatKind::Slice(ref before, ref slice, ref after) => {
1860 hir::PatKind::Slice(before.iter().map(|x| self.lower_pat(x)).collect(),
1861 slice.as_ref().map(|x| self.lower_pat(x)),
1862 after.iter().map(|x| self.lower_pat(x)).collect())
1864 PatKind::Mac(_) => panic!("Shouldn't exist here"),
1870 fn lower_range_end(&mut self, e: &RangeEnd) -> hir::RangeEnd {
1872 RangeEnd::Included(_) => hir::RangeEnd::Included,
1873 RangeEnd::Excluded => hir::RangeEnd::Excluded,
1877 fn lower_expr(&mut self, e: &Expr) -> hir::Expr {
1878 let kind = match e.node {
1880 // Eventually a desugaring for `box EXPR`
1881 // (similar to the desugaring above for `in PLACE BLOCK`)
1882 // should go here, desugaring
1886 // let mut place = BoxPlace::make_place();
1887 // let raw_place = Place::pointer(&mut place);
1888 // let value = $value;
1890 // ::std::ptr::write(raw_place, value);
1891 // Boxed::finalize(place)
1894 // But for now there are type-inference issues doing that.
1895 ExprKind::Box(ref inner) => {
1896 hir::ExprBox(P(self.lower_expr(inner)))
1899 // Desugar ExprBox: `in (PLACE) EXPR`
1900 ExprKind::InPlace(ref placer, ref value_expr) => {
1904 // let mut place = Placer::make_place(p);
1905 // let raw_place = Place::pointer(&mut place);
1907 // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR ));
1908 // InPlace::finalize(place)
1910 let placer_expr = P(self.lower_expr(placer));
1911 let value_expr = P(self.lower_expr(value_expr));
1913 let placer_ident = self.str_to_ident("placer");
1914 let place_ident = self.str_to_ident("place");
1915 let p_ptr_ident = self.str_to_ident("p_ptr");
1917 let make_place = ["ops", "Placer", "make_place"];
1918 let place_pointer = ["ops", "Place", "pointer"];
1919 let move_val_init = ["intrinsics", "move_val_init"];
1920 let inplace_finalize = ["ops", "InPlace", "finalize"];
1923 self.allow_internal_unstable(CompilerDesugaringKind::BackArrow, e.span);
1924 let make_call = |this: &mut LoweringContext, p, args| {
1925 let path = P(this.expr_std_path(unstable_span, p, ThinVec::new()));
1926 P(this.expr_call(e.span, path, args))
1929 let mk_stmt_let = |this: &mut LoweringContext, bind, expr| {
1930 this.stmt_let(e.span, false, bind, expr)
1933 let mk_stmt_let_mut = |this: &mut LoweringContext, bind, expr| {
1934 this.stmt_let(e.span, true, bind, expr)
1937 // let placer = <placer_expr> ;
1938 let (s1, placer_binding) = {
1939 mk_stmt_let(self, placer_ident, placer_expr)
1942 // let mut place = Placer::make_place(placer);
1943 let (s2, place_binding) = {
1944 let placer = self.expr_ident(e.span, placer_ident, placer_binding);
1945 let call = make_call(self, &make_place, hir_vec![placer]);
1946 mk_stmt_let_mut(self, place_ident, call)
1949 // let p_ptr = Place::pointer(&mut place);
1950 let (s3, p_ptr_binding) = {
1951 let agent = P(self.expr_ident(e.span, place_ident, place_binding));
1952 let args = hir_vec![self.expr_mut_addr_of(e.span, agent)];
1953 let call = make_call(self, &place_pointer, args);
1954 mk_stmt_let(self, p_ptr_ident, call)
1957 // pop_unsafe!(EXPR));
1958 let pop_unsafe_expr = {
1959 self.signal_block_expr(hir_vec![],
1962 hir::PopUnsafeBlock(hir::CompilerGenerated),
1967 // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR ));
1968 // InPlace::finalize(place)
1971 let ptr = self.expr_ident(e.span, p_ptr_ident, p_ptr_binding);
1972 let call_move_val_init =
1974 make_call(self, &move_val_init, hir_vec![ptr, pop_unsafe_expr]),
1975 self.next_id().node_id);
1976 let call_move_val_init = respan(e.span, call_move_val_init);
1978 let place = self.expr_ident(e.span, place_ident, place_binding);
1979 let call = make_call(self, &inplace_finalize, hir_vec![place]);
1980 P(self.signal_block_expr(hir_vec![call_move_val_init],
1983 hir::PushUnsafeBlock(hir::CompilerGenerated),
1987 let block = self.block_all(e.span, hir_vec![s1, s2, s3], Some(expr));
1988 hir::ExprBlock(P(block))
1991 ExprKind::Array(ref exprs) => {
1992 hir::ExprArray(exprs.iter().map(|x| self.lower_expr(x)).collect())
1994 ExprKind::Repeat(ref expr, ref count) => {
1995 let expr = P(self.lower_expr(expr));
1996 let count = self.lower_body(None, |this| this.lower_expr(count));
1997 hir::ExprRepeat(expr, count)
1999 ExprKind::Tup(ref elts) => {
2000 hir::ExprTup(elts.iter().map(|x| self.lower_expr(x)).collect())
2002 ExprKind::Call(ref f, ref args) => {
2003 let f = P(self.lower_expr(f));
2004 hir::ExprCall(f, args.iter().map(|x| self.lower_expr(x)).collect())
2006 ExprKind::MethodCall(ref seg, ref args) => {
2007 let hir_seg = self.lower_path_segment(e.span, seg, ParamMode::Optional, 0,
2008 ParenthesizedGenericArgs::Err);
2009 let args = args.iter().map(|x| self.lower_expr(x)).collect();
2010 hir::ExprMethodCall(hir_seg, seg.span, args)
2012 ExprKind::Binary(binop, ref lhs, ref rhs) => {
2013 let binop = self.lower_binop(binop);
2014 let lhs = P(self.lower_expr(lhs));
2015 let rhs = P(self.lower_expr(rhs));
2016 hir::ExprBinary(binop, lhs, rhs)
2018 ExprKind::Unary(op, ref ohs) => {
2019 let op = self.lower_unop(op);
2020 let ohs = P(self.lower_expr(ohs));
2021 hir::ExprUnary(op, ohs)
2023 ExprKind::Lit(ref l) => hir::ExprLit(P((**l).clone())),
2024 ExprKind::Cast(ref expr, ref ty) => {
2025 let expr = P(self.lower_expr(expr));
2026 hir::ExprCast(expr, self.lower_ty(ty))
2028 ExprKind::Type(ref expr, ref ty) => {
2029 let expr = P(self.lower_expr(expr));
2030 hir::ExprType(expr, self.lower_ty(ty))
2032 ExprKind::AddrOf(m, ref ohs) => {
2033 let m = self.lower_mutability(m);
2034 let ohs = P(self.lower_expr(ohs));
2035 hir::ExprAddrOf(m, ohs)
2037 // More complicated than you might expect because the else branch
2038 // might be `if let`.
2039 ExprKind::If(ref cond, ref blk, ref else_opt) => {
2040 let else_opt = else_opt.as_ref().map(|els| {
2042 ExprKind::IfLet(..) => {
2043 // wrap the if-let expr in a block
2044 let span = els.span;
2045 let els = P(self.lower_expr(els));
2050 let blk = P(hir::Block {
2055 rules: hir::DefaultBlock,
2057 targeted_by_break: false,
2059 P(self.expr_block(blk, ThinVec::new()))
2061 _ => P(self.lower_expr(els)),
2065 let then_blk = self.lower_block(blk, false);
2066 let then_expr = self.expr_block(then_blk, ThinVec::new());
2068 hir::ExprIf(P(self.lower_expr(cond)), P(then_expr), else_opt)
2070 ExprKind::While(ref cond, ref body, opt_ident) => {
2071 self.with_loop_scope(e.id, |this|
2073 this.with_loop_condition_scope(|this| P(this.lower_expr(cond))),
2074 this.lower_block(body, false),
2075 this.lower_opt_sp_ident(opt_ident)))
2077 ExprKind::Loop(ref body, opt_ident) => {
2078 self.with_loop_scope(e.id, |this|
2079 hir::ExprLoop(this.lower_block(body, false),
2080 this.lower_opt_sp_ident(opt_ident),
2081 hir::LoopSource::Loop))
2083 ExprKind::Catch(ref body) => {
2084 self.with_catch_scope(body.id, |this|
2085 hir::ExprBlock(this.lower_block(body, true)))
2087 ExprKind::Match(ref expr, ref arms) => {
2088 hir::ExprMatch(P(self.lower_expr(expr)),
2089 arms.iter().map(|x| self.lower_arm(x)).collect(),
2090 hir::MatchSource::Normal)
2092 ExprKind::Closure(capture_clause, ref decl, ref body, fn_decl_span) => {
2093 self.with_new_scopes(|this| {
2094 this.with_parent_def(e.id, |this| {
2095 let mut is_generator = false;
2096 let body_id = this.lower_body(Some(decl), |this| {
2097 let e = this.lower_expr(body);
2098 is_generator = this.is_generator;
2101 if is_generator && !decl.inputs.is_empty() {
2102 span_err!(this.sess, fn_decl_span, E0628,
2103 "generators cannot have explicit arguments");
2104 this.sess.abort_if_errors();
2106 hir::ExprClosure(this.lower_capture_clause(capture_clause),
2107 this.lower_fn_decl(decl),
2114 ExprKind::Block(ref blk) => hir::ExprBlock(self.lower_block(blk, false)),
2115 ExprKind::Assign(ref el, ref er) => {
2116 hir::ExprAssign(P(self.lower_expr(el)), P(self.lower_expr(er)))
2118 ExprKind::AssignOp(op, ref el, ref er) => {
2119 hir::ExprAssignOp(self.lower_binop(op),
2120 P(self.lower_expr(el)),
2121 P(self.lower_expr(er)))
2123 ExprKind::Field(ref el, ident) => {
2124 hir::ExprField(P(self.lower_expr(el)),
2125 respan(ident.span, self.lower_ident(ident.node)))
2127 ExprKind::TupField(ref el, ident) => {
2128 hir::ExprTupField(P(self.lower_expr(el)), ident)
2130 ExprKind::Index(ref el, ref er) => {
2131 hir::ExprIndex(P(self.lower_expr(el)), P(self.lower_expr(er)))
2133 ExprKind::Range(ref e1, ref e2, lims) => {
2134 use syntax::ast::RangeLimits::*;
2136 let path = match (e1, e2, lims) {
2137 (&None, &None, HalfOpen) => "RangeFull",
2138 (&Some(..), &None, HalfOpen) => "RangeFrom",
2139 (&None, &Some(..), HalfOpen) => "RangeTo",
2140 (&Some(..), &Some(..), HalfOpen) => "Range",
2141 (&None, &Some(..), Closed) => "RangeToInclusive",
2142 (&Some(..), &Some(..), Closed) => "RangeInclusive",
2143 (_, &None, Closed) =>
2144 panic!(self.diagnostic().span_fatal(
2145 e.span, "inclusive range with no end")),
2149 e1.iter().map(|e| ("start", e)).chain(e2.iter().map(|e| ("end", e)))
2151 let expr = P(self.lower_expr(&e));
2153 self.allow_internal_unstable(CompilerDesugaringKind::DotFill, e.span);
2154 self.field(Symbol::intern(s), expr, unstable_span)
2155 }).collect::<P<[hir::Field]>>();
2157 let is_unit = fields.is_empty();
2159 self.allow_internal_unstable(CompilerDesugaringKind::DotFill, e.span);
2161 iter::once("ops").chain(iter::once(path))
2162 .collect::<Vec<_>>();
2163 let struct_path = self.std_path(unstable_span, &struct_path, is_unit);
2164 let struct_path = hir::QPath::Resolved(None, P(struct_path));
2166 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(e.id);
2172 hir::ExprPath(struct_path)
2174 hir::ExprStruct(struct_path, fields, None)
2176 span: unstable_span,
2177 attrs: e.attrs.clone(),
2180 ExprKind::Path(ref qself, ref path) => {
2181 hir::ExprPath(self.lower_qpath(e.id, qself, path, ParamMode::Optional))
2183 ExprKind::Break(opt_ident, ref opt_expr) => {
2184 let label_result = if self.is_in_loop_condition && opt_ident.is_none() {
2187 target_id: hir::ScopeTarget::Loop(
2188 Err(hir::LoopIdError::UnlabeledCfInWhileCondition).into()),
2191 self.lower_loop_destination(opt_ident.map(|ident| (e.id, ident)))
2195 opt_expr.as_ref().map(|x| P(self.lower_expr(x))))
2197 ExprKind::Continue(opt_ident) =>
2199 if self.is_in_loop_condition && opt_ident.is_none() {
2202 target_id: hir::ScopeTarget::Loop(Err(
2203 hir::LoopIdError::UnlabeledCfInWhileCondition).into()),
2206 self.lower_loop_destination(opt_ident.map( |ident| (e.id, ident)))
2208 ExprKind::Ret(ref e) => hir::ExprRet(e.as_ref().map(|x| P(self.lower_expr(x)))),
2209 ExprKind::InlineAsm(ref asm) => {
2210 let hir_asm = hir::InlineAsm {
2211 inputs: asm.inputs.iter().map(|&(ref c, _)| c.clone()).collect(),
2212 outputs: asm.outputs.iter().map(|out| {
2213 hir::InlineAsmOutput {
2214 constraint: out.constraint.clone(),
2216 is_indirect: out.is_indirect,
2219 asm: asm.asm.clone(),
2220 asm_str_style: asm.asm_str_style,
2221 clobbers: asm.clobbers.clone().into(),
2222 volatile: asm.volatile,
2223 alignstack: asm.alignstack,
2224 dialect: asm.dialect,
2228 asm.outputs.iter().map(|out| self.lower_expr(&out.expr)).collect();
2230 asm.inputs.iter().map(|&(_, ref input)| self.lower_expr(input)).collect();
2231 hir::ExprInlineAsm(P(hir_asm), outputs, inputs)
2233 ExprKind::Struct(ref path, ref fields, ref maybe_expr) => {
2234 hir::ExprStruct(self.lower_qpath(e.id, &None, path, ParamMode::Optional),
2235 fields.iter().map(|x| self.lower_field(x)).collect(),
2236 maybe_expr.as_ref().map(|x| P(self.lower_expr(x))))
2238 ExprKind::Paren(ref ex) => {
2239 let mut ex = self.lower_expr(ex);
2240 // include parens in span, but only if it is a super-span.
2241 if e.span.contains(ex.span) {
2244 // merge attributes into the inner expression.
2245 let mut attrs = e.attrs.clone();
2246 attrs.extend::<Vec<_>>(ex.attrs.into());
2251 ExprKind::Yield(ref opt_expr) => {
2252 self.is_generator = true;
2253 let expr = opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| {
2254 self.expr(e.span, hir::ExprTup(hir_vec![]), ThinVec::new())
2256 hir::ExprYield(P(expr))
2259 // Desugar ExprIfLet
2260 // From: `if let <pat> = <sub_expr> <body> [<else_opt>]`
2261 ExprKind::IfLet(ref pat, ref sub_expr, ref body, ref else_opt) => {
2264 // match <sub_expr> {
2266 // _ => [<else_opt> | ()]
2269 let mut arms = vec![];
2271 // `<pat> => <body>`
2273 let body = self.lower_block(body, false);
2274 let body_expr = P(self.expr_block(body, ThinVec::new()));
2275 let pat = self.lower_pat(pat);
2276 arms.push(self.arm(hir_vec![pat], body_expr));
2279 // _ => [<else_opt>|()]
2281 let wildcard_arm: Option<&Expr> = else_opt.as_ref().map(|p| &**p);
2282 let wildcard_pattern = self.pat_wild(e.span);
2283 let body = if let Some(else_expr) = wildcard_arm {
2284 P(self.lower_expr(else_expr))
2286 self.expr_tuple(e.span, hir_vec![])
2288 arms.push(self.arm(hir_vec![wildcard_pattern], body));
2291 let contains_else_clause = else_opt.is_some();
2293 let sub_expr = P(self.lower_expr(sub_expr));
2298 hir::MatchSource::IfLetDesugar {
2299 contains_else_clause,
2303 // Desugar ExprWhileLet
2304 // From: `[opt_ident]: while let <pat> = <sub_expr> <body>`
2305 ExprKind::WhileLet(ref pat, ref sub_expr, ref body, opt_ident) => {
2308 // [opt_ident]: loop {
2309 // match <sub_expr> {
2315 // Note that the block AND the condition are evaluated in the loop scope.
2316 // This is done to allow `break` from inside the condition of the loop.
2317 let (body, break_expr, sub_expr) = self.with_loop_scope(e.id, |this| (
2318 this.lower_block(body, false),
2319 this.expr_break(e.span, ThinVec::new()),
2320 this.with_loop_condition_scope(|this| P(this.lower_expr(sub_expr))),
2323 // `<pat> => <body>`
2325 let body_expr = P(self.expr_block(body, ThinVec::new()));
2326 let pat = self.lower_pat(pat);
2327 self.arm(hir_vec![pat], body_expr)
2332 let pat_under = self.pat_wild(e.span);
2333 self.arm(hir_vec![pat_under], break_expr)
2336 // `match <sub_expr> { ... }`
2337 let arms = hir_vec![pat_arm, break_arm];
2338 let match_expr = self.expr(e.span,
2339 hir::ExprMatch(sub_expr,
2341 hir::MatchSource::WhileLetDesugar),
2344 // `[opt_ident]: loop { ... }`
2345 let loop_block = P(self.block_expr(P(match_expr)));
2346 let loop_expr = hir::ExprLoop(loop_block, self.lower_opt_sp_ident(opt_ident),
2347 hir::LoopSource::WhileLet);
2348 // add attributes to the outer returned expr node
2352 // Desugar ExprForLoop
2353 // From: `[opt_ident]: for <pat> in <head> <body>`
2354 ExprKind::ForLoop(ref pat, ref head, ref body, opt_ident) => {
2358 // let result = match ::std::iter::IntoIterator::into_iter(<head>) {
2360 // [opt_ident]: loop {
2362 // match ::std::iter::Iterator::next(&mut iter) {
2363 // ::std::option::Option::Some(val) => __next = val,
2364 // ::std::option::Option::None => break
2366 // let <pat> = __next;
2367 // StmtExpr(<body>);
2375 let head = self.lower_expr(head);
2377 let iter = self.str_to_ident("iter");
2379 let next_ident = self.str_to_ident("__next");
2380 let next_pat = self.pat_ident_binding_mode(e.span,
2382 hir::BindingAnnotation::Mutable);
2384 // `::std::option::Option::Some(val) => next = val`
2386 let val_ident = self.str_to_ident("val");
2387 let val_pat = self.pat_ident(e.span, val_ident);
2388 let val_expr = P(self.expr_ident(e.span, val_ident, val_pat.id));
2389 let next_expr = P(self.expr_ident(e.span, next_ident, next_pat.id));
2390 let assign = P(self.expr(e.span,
2391 hir::ExprAssign(next_expr, val_expr),
2393 let some_pat = self.pat_some(e.span, val_pat);
2394 self.arm(hir_vec![some_pat], assign)
2397 // `::std::option::Option::None => break`
2399 let break_expr = self.with_loop_scope(e.id, |this|
2400 this.expr_break(e.span, ThinVec::new()));
2401 let pat = self.pat_none(e.span);
2402 self.arm(hir_vec![pat], break_expr)
2406 let iter_pat = self.pat_ident_binding_mode(e.span,
2408 hir::BindingAnnotation::Mutable);
2410 // `match ::std::iter::Iterator::next(&mut iter) { ... }`
2412 let iter = P(self.expr_ident(e.span, iter, iter_pat.id));
2413 let ref_mut_iter = self.expr_mut_addr_of(e.span, iter);
2414 let next_path = &["iter", "Iterator", "next"];
2415 let next_path = P(self.expr_std_path(e.span, next_path, ThinVec::new()));
2416 let next_expr = P(self.expr_call(e.span, next_path,
2417 hir_vec![ref_mut_iter]));
2418 let arms = hir_vec![pat_arm, break_arm];
2421 hir::ExprMatch(next_expr, arms,
2422 hir::MatchSource::ForLoopDesugar),
2425 let match_stmt = respan(e.span, hir::StmtExpr(match_expr, self.next_id().node_id));
2427 let next_expr = P(self.expr_ident(e.span, next_ident, next_pat.id));
2430 let next_let = self.stmt_let_pat(e.span,
2433 hir::LocalSource::ForLoopDesugar);
2435 // `let <pat> = __next`
2436 let pat = self.lower_pat(pat);
2437 let pat_let = self.stmt_let_pat(e.span,
2440 hir::LocalSource::ForLoopDesugar);
2442 let body_block = self.with_loop_scope(e.id,
2443 |this| this.lower_block(body, false));
2444 let body_expr = P(self.expr_block(body_block, ThinVec::new()));
2445 let body_stmt = respan(e.span, hir::StmtExpr(body_expr, self.next_id().node_id));
2447 let loop_block = P(self.block_all(e.span,
2454 // `[opt_ident]: loop { ... }`
2455 let loop_expr = hir::ExprLoop(loop_block, self.lower_opt_sp_ident(opt_ident),
2456 hir::LoopSource::ForLoop);
2457 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(e.id);
2458 let loop_expr = P(hir::Expr {
2463 attrs: ThinVec::new(),
2466 // `mut iter => { ... }`
2467 let iter_arm = self.arm(hir_vec![iter_pat], loop_expr);
2469 // `match ::std::iter::IntoIterator::into_iter(<head>) { ... }`
2470 let into_iter_expr = {
2471 let into_iter_path = &["iter", "IntoIterator", "into_iter"];
2472 let into_iter = P(self.expr_std_path(e.span, into_iter_path,
2474 P(self.expr_call(e.span, into_iter, hir_vec![head]))
2477 let match_expr = P(self.expr_match(e.span,
2480 hir::MatchSource::ForLoopDesugar));
2482 // `{ let _result = ...; _result }`
2483 // underscore prevents an unused_variables lint if the head diverges
2484 let result_ident = self.str_to_ident("_result");
2485 let (let_stmt, let_stmt_binding) =
2486 self.stmt_let(e.span, false, result_ident, match_expr);
2488 let result = P(self.expr_ident(e.span, result_ident, let_stmt_binding));
2489 let block = P(self.block_all(e.span, hir_vec![let_stmt], Some(result)));
2490 // add the attributes to the outer returned expr node
2491 return self.expr_block(block, e.attrs.clone());
2494 // Desugar ExprKind::Try
2496 ExprKind::Try(ref sub_expr) => {
2499 // match Try::into_result(<expr>) {
2500 // Ok(val) => #[allow(unreachable_code)] val,
2501 // Err(err) => #[allow(unreachable_code)]
2502 // // If there is an enclosing `catch {...}`
2503 // break 'catch_target Try::from_error(From::from(err)),
2505 // return Try::from_error(From::from(err)),
2509 self.allow_internal_unstable(CompilerDesugaringKind::QuestionMark, e.span);
2511 // Try::into_result(<expr>)
2514 let sub_expr = self.lower_expr(sub_expr);
2516 let path = &["ops", "Try", "into_result"];
2517 let path = P(self.expr_std_path(unstable_span, path, ThinVec::new()));
2518 P(self.expr_call(e.span, path, hir_vec![sub_expr]))
2521 // #[allow(unreachable_code)]
2523 // allow(unreachable_code)
2525 let allow_ident = self.str_to_ident("allow");
2526 let uc_ident = self.str_to_ident("unreachable_code");
2527 let uc_meta_item = attr::mk_spanned_word_item(e.span, uc_ident);
2528 let uc_nested = NestedMetaItemKind::MetaItem(uc_meta_item);
2529 let uc_spanned = respan(e.span, uc_nested);
2530 attr::mk_spanned_list_item(e.span, allow_ident, vec![uc_spanned])
2532 attr::mk_spanned_attr_outer(e.span, attr::mk_attr_id(), allow)
2534 let attrs = vec![attr];
2536 // Ok(val) => #[allow(unreachable_code)] val,
2538 let val_ident = self.str_to_ident("val");
2539 let val_pat = self.pat_ident(e.span, val_ident);
2540 let val_expr = P(self.expr_ident_with_attrs(e.span,
2543 ThinVec::from(attrs.clone())));
2544 let ok_pat = self.pat_ok(e.span, val_pat);
2546 self.arm(hir_vec![ok_pat], val_expr)
2549 // Err(err) => #[allow(unreachable_code)]
2550 // return Carrier::from_error(From::from(err)),
2552 let err_ident = self.str_to_ident("err");
2553 let err_local = self.pat_ident(e.span, err_ident);
2555 let path = &["convert", "From", "from"];
2556 let from = P(self.expr_std_path(e.span, path, ThinVec::new()));
2557 let err_expr = self.expr_ident(e.span, err_ident, err_local.id);
2559 self.expr_call(e.span, from, hir_vec![err_expr])
2561 let from_err_expr = {
2562 let path = &["ops", "Try", "from_error"];
2563 let from_err = P(self.expr_std_path(unstable_span, path,
2565 P(self.expr_call(e.span, from_err, hir_vec![from_expr]))
2568 let thin_attrs = ThinVec::from(attrs);
2569 let catch_scope = self.catch_scopes.last().map(|x| *x);
2570 let ret_expr = if let Some(catch_node) = catch_scope {
2576 target_id: hir::ScopeTarget::Block(catch_node),
2583 hir::Expr_::ExprRet(Some(from_err_expr)),
2588 let err_pat = self.pat_err(e.span, err_local);
2589 self.arm(hir_vec![err_pat], ret_expr)
2592 hir::ExprMatch(discr,
2593 hir_vec![err_arm, ok_arm],
2594 hir::MatchSource::TryDesugar)
2597 ExprKind::Mac(_) => panic!("Shouldn't exist here"),
2600 let LoweredNodeId { node_id, hir_id } = self.lower_node_id(e.id);
2607 attrs: e.attrs.clone(),
2611 fn lower_stmt(&mut self, s: &Stmt) -> SmallVector<hir::Stmt> {
2612 SmallVector::one(match s.node {
2613 StmtKind::Local(ref l) => Spanned {
2614 node: hir::StmtDecl(P(Spanned {
2615 node: hir::DeclLocal(self.lower_local(l)),
2617 }), self.lower_node_id(s.id).node_id),
2620 StmtKind::Item(ref it) => {
2621 // Can only use the ID once.
2622 let mut id = Some(s.id);
2623 return self.lower_item_id(it).into_iter().map(|item_id| Spanned {
2624 node: hir::StmtDecl(P(Spanned {
2625 node: hir::DeclItem(item_id),
2628 .map(|id| self.lower_node_id(id).node_id)
2629 .unwrap_or_else(|| self.next_id().node_id)),
2633 StmtKind::Expr(ref e) => {
2635 node: hir::StmtExpr(P(self.lower_expr(e)),
2636 self.lower_node_id(s.id).node_id),
2640 StmtKind::Semi(ref e) => {
2642 node: hir::StmtSemi(P(self.lower_expr(e)),
2643 self.lower_node_id(s.id).node_id),
2647 StmtKind::Mac(..) => panic!("Shouldn't exist here"),
2651 fn lower_capture_clause(&mut self, c: CaptureBy) -> hir::CaptureClause {
2653 CaptureBy::Value => hir::CaptureByValue,
2654 CaptureBy::Ref => hir::CaptureByRef,
2658 /// If an `explicit_owner` is given, this method allocates the `HirId` in
2659 /// the address space of that item instead of the item currently being
2660 /// lowered. This can happen during `lower_impl_item_ref()` where we need to
2661 /// lower a `Visibility` value although we haven't lowered the owning
2662 /// `ImplItem` in question yet.
2663 fn lower_visibility(&mut self,
2665 explicit_owner: Option<NodeId>)
2666 -> hir::Visibility {
2668 Visibility::Public => hir::Public,
2669 Visibility::Crate(_) => hir::Visibility::Crate,
2670 Visibility::Restricted { ref path, id } => {
2671 hir::Visibility::Restricted {
2672 path: P(self.lower_path(id, path, ParamMode::Explicit, true)),
2673 id: if let Some(owner) = explicit_owner {
2674 self.lower_node_id_with_owner(id, owner).node_id
2676 self.lower_node_id(id).node_id
2680 Visibility::Inherited => hir::Inherited,
2684 fn lower_defaultness(&mut self, d: Defaultness, has_value: bool) -> hir::Defaultness {
2686 Defaultness::Default => hir::Defaultness::Default { has_value: has_value },
2687 Defaultness::Final => {
2689 hir::Defaultness::Final
2694 fn lower_block_check_mode(&mut self, b: &BlockCheckMode) -> hir::BlockCheckMode {
2696 BlockCheckMode::Default => hir::DefaultBlock,
2697 BlockCheckMode::Unsafe(u) => hir::UnsafeBlock(self.lower_unsafe_source(u)),
2701 fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation {
2703 BindingMode::ByValue(Mutability::Immutable) =>
2704 hir::BindingAnnotation::Unannotated,
2705 BindingMode::ByRef(Mutability::Immutable) => hir::BindingAnnotation::Ref,
2706 BindingMode::ByValue(Mutability::Mutable) => hir::BindingAnnotation::Mutable,
2707 BindingMode::ByRef(Mutability::Mutable) => hir::BindingAnnotation::RefMut,
2711 fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource {
2713 CompilerGenerated => hir::CompilerGenerated,
2714 UserProvided => hir::UserProvided,
2718 fn lower_impl_polarity(&mut self, i: ImplPolarity) -> hir::ImplPolarity {
2720 ImplPolarity::Positive => hir::ImplPolarity::Positive,
2721 ImplPolarity::Negative => hir::ImplPolarity::Negative,
2725 fn lower_trait_bound_modifier(&mut self, f: TraitBoundModifier) -> hir::TraitBoundModifier {
2727 TraitBoundModifier::None => hir::TraitBoundModifier::None,
2728 TraitBoundModifier::Maybe => hir::TraitBoundModifier::Maybe,
2732 // Helper methods for building HIR.
2734 fn arm(&mut self, pats: hir::HirVec<P<hir::Pat>>, expr: P<hir::Expr>) -> hir::Arm {
2743 fn field(&mut self, name: Name, expr: P<hir::Expr>, span: Span) -> hir::Field {
2751 is_shorthand: false,
2755 fn expr_break(&mut self, span: Span, attrs: ThinVec<Attribute>) -> P<hir::Expr> {
2756 let expr_break = hir::ExprBreak(self.lower_loop_destination(None), None);
2757 P(self.expr(span, expr_break, attrs))
2760 fn expr_call(&mut self, span: Span, e: P<hir::Expr>, args: hir::HirVec<hir::Expr>)
2762 self.expr(span, hir::ExprCall(e, args), ThinVec::new())
2765 fn expr_ident(&mut self, span: Span, id: Name, binding: NodeId) -> hir::Expr {
2766 self.expr_ident_with_attrs(span, id, binding, ThinVec::new())
2769 fn expr_ident_with_attrs(&mut self, span: Span,
2772 attrs: ThinVec<Attribute>) -> hir::Expr {
2773 let expr_path = hir::ExprPath(hir::QPath::Resolved(None, P(hir::Path {
2775 def: Def::Local(binding),
2776 segments: hir_vec![hir::PathSegment::from_name(id)],
2779 self.expr(span, expr_path, attrs)
2782 fn expr_mut_addr_of(&mut self, span: Span, e: P<hir::Expr>) -> hir::Expr {
2783 self.expr(span, hir::ExprAddrOf(hir::MutMutable, e), ThinVec::new())
2786 fn expr_std_path(&mut self,
2788 components: &[&str],
2789 attrs: ThinVec<Attribute>)
2791 let path = self.std_path(span, components, true);
2792 self.expr(span, hir::ExprPath(hir::QPath::Resolved(None, P(path))), attrs)
2795 fn expr_match(&mut self,
2798 arms: hir::HirVec<hir::Arm>,
2799 source: hir::MatchSource)
2801 self.expr(span, hir::ExprMatch(arg, arms, source), ThinVec::new())
2804 fn expr_block(&mut self, b: P<hir::Block>, attrs: ThinVec<Attribute>) -> hir::Expr {
2805 self.expr(b.span, hir::ExprBlock(b), attrs)
2808 fn expr_tuple(&mut self, sp: Span, exprs: hir::HirVec<hir::Expr>) -> P<hir::Expr> {
2809 P(self.expr(sp, hir::ExprTup(exprs), ThinVec::new()))
2812 fn expr(&mut self, span: Span, node: hir::Expr_, attrs: ThinVec<Attribute>) -> hir::Expr {
2813 let LoweredNodeId { node_id, hir_id } = self.next_id();
2823 fn stmt_let_pat(&mut self,
2825 ex: Option<P<hir::Expr>>,
2827 source: hir::LocalSource)
2829 let LoweredNodeId { node_id, hir_id } = self.next_id();
2831 let local = P(hir::Local {
2838 attrs: ThinVec::new(),
2841 let decl = respan(sp, hir::DeclLocal(local));
2842 respan(sp, hir::StmtDecl(P(decl), self.next_id().node_id))
2845 fn stmt_let(&mut self, sp: Span, mutbl: bool, ident: Name, ex: P<hir::Expr>)
2846 -> (hir::Stmt, NodeId) {
2847 let pat = if mutbl {
2848 self.pat_ident_binding_mode(sp, ident, hir::BindingAnnotation::Mutable)
2850 self.pat_ident(sp, ident)
2852 let pat_id = pat.id;
2853 (self.stmt_let_pat(sp, Some(ex), pat, hir::LocalSource::Normal), pat_id)
2856 fn block_expr(&mut self, expr: P<hir::Expr>) -> hir::Block {
2857 self.block_all(expr.span, hir::HirVec::new(), Some(expr))
2860 fn block_all(&mut self, span: Span, stmts: hir::HirVec<hir::Stmt>, expr: Option<P<hir::Expr>>)
2862 let LoweredNodeId { node_id, hir_id } = self.next_id();
2869 rules: hir::DefaultBlock,
2871 targeted_by_break: false,
2875 fn pat_ok(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
2876 self.pat_std_enum(span, &["result", "Result", "Ok"], hir_vec![pat])
2879 fn pat_err(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
2880 self.pat_std_enum(span, &["result", "Result", "Err"], hir_vec![pat])
2883 fn pat_some(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
2884 self.pat_std_enum(span, &["option", "Option", "Some"], hir_vec![pat])
2887 fn pat_none(&mut self, span: Span) -> P<hir::Pat> {
2888 self.pat_std_enum(span, &["option", "Option", "None"], hir_vec![])
2891 fn pat_std_enum(&mut self,
2893 components: &[&str],
2894 subpats: hir::HirVec<P<hir::Pat>>)
2896 let path = self.std_path(span, components, true);
2897 let qpath = hir::QPath::Resolved(None, P(path));
2898 let pt = if subpats.is_empty() {
2899 hir::PatKind::Path(qpath)
2901 hir::PatKind::TupleStruct(qpath, subpats, None)
2906 fn pat_ident(&mut self, span: Span, name: Name) -> P<hir::Pat> {
2907 self.pat_ident_binding_mode(span, name, hir::BindingAnnotation::Unannotated)
2910 fn pat_ident_binding_mode(&mut self, span: Span, name: Name, bm: hir::BindingAnnotation)
2912 let LoweredNodeId { node_id, hir_id } = self.next_id();
2917 node: hir::PatKind::Binding(bm,
2928 fn pat_wild(&mut self, span: Span) -> P<hir::Pat> {
2929 self.pat(span, hir::PatKind::Wild)
2932 fn pat(&mut self, span: Span, pat: hir::PatKind) -> P<hir::Pat> {
2933 let LoweredNodeId { node_id, hir_id } = self.next_id();
2942 /// Given suffix ["b","c","d"], returns path `::std::b::c::d` when
2943 /// `fld.cx.use_std`, and `::core::b::c::d` otherwise.
2944 /// The path is also resolved according to `is_value`.
2945 fn std_path(&mut self, span: Span, components: &[&str], is_value: bool) -> hir::Path {
2946 let mut path = hir::Path {
2949 segments: iter::once(keywords::CrateRoot.name()).chain({
2950 self.crate_root.into_iter().chain(components.iter().cloned()).map(Symbol::intern)
2951 }).map(hir::PathSegment::from_name).collect(),
2954 self.resolver.resolve_hir_path(&mut path, is_value);
2958 fn signal_block_expr(&mut self,
2959 stmts: hir::HirVec<hir::Stmt>,
2962 rule: hir::BlockCheckMode,
2963 attrs: ThinVec<Attribute>)
2965 let LoweredNodeId { node_id, hir_id } = self.next_id();
2967 let block = P(hir::Block {
2974 targeted_by_break: false,
2976 self.expr_block(block, attrs)
2979 fn ty_path(&mut self, id: LoweredNodeId, span: Span, qpath: hir::QPath) -> P<hir::Ty> {
2981 let node = match qpath {
2982 hir::QPath::Resolved(None, path) => {
2983 // Turn trait object paths into `TyTraitObject` instead.
2984 if let Def::Trait(_) = path.def {
2985 let principal = hir::PolyTraitRef {
2986 bound_lifetimes: hir_vec![],
2987 trait_ref: hir::TraitRef {
2988 path: path.and_then(|path| path),
2994 // The original ID is taken by the `PolyTraitRef`,
2995 // so the `Ty` itself needs a different one.
2996 id = self.next_id();
2998 hir::TyTraitObject(hir_vec![principal], self.elided_lifetime(span))
3000 hir::TyPath(hir::QPath::Resolved(None, path))
3003 _ => hir::TyPath(qpath)
3005 P(hir::Ty { id: id.node_id, hir_id: id.hir_id, node, span })
3008 fn elided_lifetime(&mut self, span: Span) -> hir::Lifetime {
3010 id: self.next_id().node_id,
3012 name: hir::LifetimeName::Implicit,
3017 fn body_ids(bodies: &BTreeMap<hir::BodyId, hir::Body>) -> Vec<hir::BodyId> {
3018 // Sorting by span ensures that we get things in order within a
3019 // file, and also puts the files in a sensible order.
3020 let mut body_ids: Vec<_> = bodies.keys().cloned().collect();
3021 body_ids.sort_by_key(|b| bodies[b].value.span);