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.
44 use hir::map::Definitions;
45 use hir::map::definitions::DefPathData;
46 use hir::def_id::{DefIndex, DefId};
47 use hir::def::{Def, PathResolution};
50 use std::collections::BTreeMap;
55 use syntax::codemap::{respan, Spanned};
56 use syntax::parse::token;
57 use syntax::std_inject;
58 use syntax::visit::{self, Visitor};
61 pub struct LoweringContext<'a> {
62 crate_root: Option<&'static str>,
63 // Use to assign ids to hir nodes that do not directly correspond to an ast node
64 sess: Option<&'a Session>,
65 // As we walk the AST we must keep track of the current 'parent' def id (in
66 // the form of a DefIndex) so that if we create a new node which introduces
67 // a definition, then we can properly create the def id.
68 parent_def: Option<DefIndex>,
69 resolver: &'a mut Resolver,
73 // Resolve a global hir path generated by the lowerer when expanding `for`, `if let`, etc.
74 fn resolve_generated_global_path(&mut self, path: &hir::Path, is_value: bool) -> Def;
76 // Obtain the resolution for a node id
77 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution>;
79 // Record the resolution of a path or binding generated by the lowerer when expanding.
80 fn record_resolution(&mut self, id: NodeId, def: Def);
82 // We must keep the set of definitions up to date as we add nodes that weren't in the AST.
83 // This should only return `None` during testing.
84 fn definitions(&mut self) -> Option<&mut Definitions>;
87 pub struct DummyResolver;
88 impl Resolver for DummyResolver {
89 fn resolve_generated_global_path(&mut self, _path: &hir::Path, _is_value: bool) -> Def {
92 fn get_resolution(&mut self, _id: NodeId) -> Option<PathResolution> {
95 fn record_resolution(&mut self, _id: NodeId, _def: Def) {}
96 fn definitions(&mut self) -> Option<&mut Definitions> {
101 pub fn lower_crate(sess: &Session,
103 resolver: &mut Resolver)
105 // We're constructing the HIR here; we don't care what we will
106 // read, since we haven't even constructed the *input* to
108 let _ignore = sess.dep_graph.in_ignore();
111 crate_root: if std_inject::no_core(krate) {
113 } else if std_inject::no_std(krate) {
124 impl<'a> LoweringContext<'a> {
125 pub fn testing_context(resolver: &'a mut Resolver) -> Self {
134 fn lower_crate(&mut self, c: &Crate) -> hir::Crate {
135 struct ItemLowerer<'lcx, 'interner: 'lcx> {
136 items: BTreeMap<NodeId, hir::Item>,
137 lctx: &'lcx mut LoweringContext<'interner>,
140 impl<'lcx, 'interner> Visitor for ItemLowerer<'lcx, 'interner> {
141 fn visit_item(&mut self, item: &Item) {
142 self.items.insert(item.id, self.lctx.lower_item(item));
143 visit::walk_item(self, item);
148 let mut item_lowerer = ItemLowerer { items: BTreeMap::new(), lctx: self };
149 visit::walk_crate(&mut item_lowerer, c);
154 module: self.lower_mod(&c.module),
155 attrs: self.lower_attrs(&c.attrs),
156 config: c.config.clone().into(),
158 exported_macros: c.exported_macros.iter().map(|m| self.lower_macro_def(m)).collect(),
163 fn next_id(&self) -> NodeId {
164 self.sess.map(Session::next_node_id).unwrap_or(0)
167 fn diagnostic(&self) -> &errors::Handler {
168 self.sess.map(Session::diagnostic)
169 .unwrap_or_else(|| panic!("this lowerer cannot emit diagnostics"))
172 fn str_to_ident(&self, s: &'static str) -> Name {
176 fn with_parent_def<T, F>(&mut self, parent_id: NodeId, f: F) -> T
177 where F: FnOnce(&mut LoweringContext) -> T
179 let old_def = self.parent_def;
180 self.parent_def = match self.resolver.definitions() {
181 Some(defs) => Some(defs.opt_def_index(parent_id).unwrap()),
185 let result = f(self);
187 self.parent_def = old_def;
191 fn lower_opt_sp_ident(&mut self, o_id: Option<Spanned<Ident>>) -> Option<Spanned<Name>> {
192 o_id.map(|sp_ident| respan(sp_ident.span, sp_ident.node.name))
195 fn lower_attrs(&mut self, attrs: &Vec<Attribute>) -> hir::HirVec<Attribute> {
199 fn lower_view_path(&mut self, view_path: &ViewPath) -> P<hir::ViewPath> {
201 node: match view_path.node {
202 ViewPathSimple(ident, ref path) => {
203 hir::ViewPathSimple(ident.name, self.lower_path(path))
205 ViewPathGlob(ref path) => {
206 hir::ViewPathGlob(self.lower_path(path))
208 ViewPathList(ref path, ref path_list_idents) => {
209 hir::ViewPathList(self.lower_path(path),
210 path_list_idents.iter()
211 .map(|item| self.lower_path_list_item(item))
215 span: view_path.span,
219 fn lower_path_list_item(&mut self, path_list_ident: &PathListItem) -> hir::PathListItem {
221 node: hir::PathListItem_ {
222 id: path_list_ident.node.id,
223 name: path_list_ident.node.name.name,
224 rename: path_list_ident.node.rename.map(|rename| rename.name),
226 span: path_list_ident.span,
230 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm {
232 attrs: self.lower_attrs(&arm.attrs),
233 pats: arm.pats.iter().map(|x| self.lower_pat(x)).collect(),
234 guard: arm.guard.as_ref().map(|ref x| self.lower_expr(x)),
235 body: self.lower_expr(&arm.body),
239 fn lower_ty_binding(&mut self, b: &TypeBinding) -> hir::TypeBinding {
243 ty: self.lower_ty(&b.ty),
248 fn lower_ty(&mut self, t: &Ty) -> P<hir::Ty> {
249 use syntax::ast::TyKind::*;
253 Infer | ImplicitSelf => hir::TyInfer,
254 Vec(ref ty) => hir::TyVec(self.lower_ty(ty)),
255 Ptr(ref mt) => hir::TyPtr(self.lower_mt(mt)),
256 Rptr(ref region, ref mt) => {
257 hir::TyRptr(self.lower_opt_lifetime(region), self.lower_mt(mt))
260 hir::TyBareFn(P(hir::BareFnTy {
261 lifetimes: self.lower_lifetime_defs(&f.lifetimes),
262 unsafety: self.lower_unsafety(f.unsafety),
264 decl: self.lower_fn_decl(&f.decl),
267 Never => hir::TyNever,
268 Tup(ref tys) => hir::TyTup(tys.iter().map(|ty| self.lower_ty(ty)).collect()),
270 return self.lower_ty(ty);
272 Path(ref qself, ref path) => {
273 let qself = qself.as_ref().map(|&QSelf { ref ty, position }| {
275 ty: self.lower_ty(ty),
279 hir::TyPath(qself, self.lower_path(path))
281 ObjectSum(ref ty, ref bounds) => {
282 hir::TyObjectSum(self.lower_ty(ty), self.lower_bounds(bounds))
284 FixedLengthVec(ref ty, ref e) => {
285 hir::TyFixedLengthVec(self.lower_ty(ty), self.lower_expr(e))
287 Typeof(ref expr) => {
288 hir::TyTypeof(self.lower_expr(expr))
290 PolyTraitRef(ref bounds) => {
291 hir::TyPolyTraitRef(self.lower_bounds(bounds))
293 ImplTrait(ref bounds) => {
294 hir::TyImplTrait(self.lower_bounds(bounds))
296 Mac(_) => panic!("TyMac should have been expanded by now."),
302 fn lower_foreign_mod(&mut self, fm: &ForeignMod) -> hir::ForeignMod {
305 items: fm.items.iter().map(|x| self.lower_foreign_item(x)).collect(),
309 fn lower_variant(&mut self, v: &Variant) -> hir::Variant {
311 node: hir::Variant_ {
312 name: v.node.name.name,
313 attrs: self.lower_attrs(&v.node.attrs),
314 data: self.lower_variant_data(&v.node.data),
315 disr_expr: v.node.disr_expr.as_ref().map(|e| self.lower_expr(e)),
321 fn lower_path(&mut self, p: &Path) -> hir::Path {
326 .map(|&PathSegment { identifier, ref parameters }| {
328 name: identifier.name,
329 parameters: self.lower_path_parameters(parameters),
337 fn lower_path_parameters(&mut self, path_parameters: &PathParameters) -> hir::PathParameters {
338 match *path_parameters {
339 PathParameters::AngleBracketed(ref data) =>
340 hir::AngleBracketedParameters(self.lower_angle_bracketed_parameter_data(data)),
341 PathParameters::Parenthesized(ref data) =>
342 hir::ParenthesizedParameters(self.lower_parenthesized_parameter_data(data)),
346 fn lower_angle_bracketed_parameter_data(&mut self,
347 data: &AngleBracketedParameterData)
348 -> hir::AngleBracketedParameterData {
349 let &AngleBracketedParameterData { ref lifetimes, ref types, ref bindings } = data;
350 hir::AngleBracketedParameterData {
351 lifetimes: self.lower_lifetimes(lifetimes),
352 types: types.iter().map(|ty| self.lower_ty(ty)).collect(),
353 bindings: bindings.iter().map(|b| self.lower_ty_binding(b)).collect(),
357 fn lower_parenthesized_parameter_data(&mut self,
358 data: &ParenthesizedParameterData)
359 -> hir::ParenthesizedParameterData {
360 let &ParenthesizedParameterData { ref inputs, ref output, span } = data;
361 hir::ParenthesizedParameterData {
362 inputs: inputs.iter().map(|ty| self.lower_ty(ty)).collect(),
363 output: output.as_ref().map(|ty| self.lower_ty(ty)),
368 fn lower_local(&mut self, l: &Local) -> P<hir::Local> {
371 ty: l.ty.as_ref().map(|t| self.lower_ty(t)),
372 pat: self.lower_pat(&l.pat),
373 init: l.init.as_ref().map(|e| self.lower_expr(e)),
375 attrs: l.attrs.clone(),
379 fn lower_mutability(&mut self, m: Mutability) -> hir::Mutability {
381 Mutability::Mutable => hir::MutMutable,
382 Mutability::Immutable => hir::MutImmutable,
386 fn lower_arg(&mut self, arg: &Arg) -> hir::Arg {
389 pat: self.lower_pat(&arg.pat),
390 ty: self.lower_ty(&arg.ty),
394 fn lower_fn_decl(&mut self, decl: &FnDecl) -> P<hir::FnDecl> {
396 inputs: decl.inputs.iter().map(|x| self.lower_arg(x)).collect(),
397 output: match decl.output {
398 FunctionRetTy::Ty(ref ty) => hir::Return(self.lower_ty(ty)),
399 FunctionRetTy::Default(span) => hir::DefaultReturn(span),
401 variadic: decl.variadic,
405 fn lower_ty_param_bound(&mut self, tpb: &TyParamBound) -> hir::TyParamBound {
407 TraitTyParamBound(ref ty, modifier) => {
408 hir::TraitTyParamBound(self.lower_poly_trait_ref(ty),
409 self.lower_trait_bound_modifier(modifier))
411 RegionTyParamBound(ref lifetime) => {
412 hir::RegionTyParamBound(self.lower_lifetime(lifetime))
417 fn lower_ty_param(&mut self, tp: &TyParam) -> hir::TyParam {
421 bounds: self.lower_bounds(&tp.bounds),
422 default: tp.default.as_ref().map(|x| self.lower_ty(x)),
427 fn lower_ty_params(&mut self, tps: &P<[TyParam]>) -> hir::HirVec<hir::TyParam> {
428 tps.iter().map(|tp| self.lower_ty_param(tp)).collect()
431 fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime {
439 fn lower_lifetime_def(&mut self, l: &LifetimeDef) -> hir::LifetimeDef {
441 lifetime: self.lower_lifetime(&l.lifetime),
442 bounds: self.lower_lifetimes(&l.bounds),
446 fn lower_lifetimes(&mut self, lts: &Vec<Lifetime>) -> hir::HirVec<hir::Lifetime> {
447 lts.iter().map(|l| self.lower_lifetime(l)).collect()
450 fn lower_lifetime_defs(&mut self, lts: &Vec<LifetimeDef>) -> hir::HirVec<hir::LifetimeDef> {
451 lts.iter().map(|l| self.lower_lifetime_def(l)).collect()
454 fn lower_opt_lifetime(&mut self, o_lt: &Option<Lifetime>) -> Option<hir::Lifetime> {
455 o_lt.as_ref().map(|lt| self.lower_lifetime(lt))
458 fn lower_generics(&mut self, g: &Generics) -> hir::Generics {
460 ty_params: self.lower_ty_params(&g.ty_params),
461 lifetimes: self.lower_lifetime_defs(&g.lifetimes),
462 where_clause: self.lower_where_clause(&g.where_clause),
467 fn lower_where_clause(&mut self, wc: &WhereClause) -> hir::WhereClause {
470 predicates: wc.predicates
472 .map(|predicate| self.lower_where_predicate(predicate))
477 fn lower_where_predicate(&mut self, pred: &WherePredicate) -> hir::WherePredicate {
479 WherePredicate::BoundPredicate(WhereBoundPredicate{ ref bound_lifetimes,
483 hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
484 bound_lifetimes: self.lower_lifetime_defs(bound_lifetimes),
485 bounded_ty: self.lower_ty(bounded_ty),
486 bounds: bounds.iter().map(|x| self.lower_ty_param_bound(x)).collect(),
490 WherePredicate::RegionPredicate(WhereRegionPredicate{ ref lifetime,
493 hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
495 lifetime: self.lower_lifetime(lifetime),
496 bounds: bounds.iter().map(|bound| self.lower_lifetime(bound)).collect(),
499 WherePredicate::EqPredicate(WhereEqPredicate{ id,
503 hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
505 path: self.lower_path(path),
506 ty: self.lower_ty(ty),
513 fn lower_variant_data(&mut self, vdata: &VariantData) -> hir::VariantData {
515 VariantData::Struct(ref fields, id) => {
516 hir::VariantData::Struct(fields.iter()
518 .map(|f| self.lower_struct_field(f))
522 VariantData::Tuple(ref fields, id) => {
523 hir::VariantData::Tuple(fields.iter()
525 .map(|f| self.lower_struct_field(f))
529 VariantData::Unit(id) => hir::VariantData::Unit(id),
533 fn lower_trait_ref(&mut self, p: &TraitRef) -> hir::TraitRef {
535 path: self.lower_path(&p.path),
540 fn lower_poly_trait_ref(&mut self, p: &PolyTraitRef) -> hir::PolyTraitRef {
542 bound_lifetimes: self.lower_lifetime_defs(&p.bound_lifetimes),
543 trait_ref: self.lower_trait_ref(&p.trait_ref),
548 fn lower_struct_field(&mut self, (index, f): (usize, &StructField)) -> hir::StructField {
552 name: f.ident.map(|ident| ident.name).unwrap_or(token::intern(&index.to_string())),
553 vis: self.lower_visibility(&f.vis),
554 ty: self.lower_ty(&f.ty),
555 attrs: self.lower_attrs(&f.attrs),
559 fn lower_field(&mut self, f: &Field) -> hir::Field {
561 name: respan(f.ident.span, f.ident.node.name),
562 expr: self.lower_expr(&f.expr),
567 fn lower_mt(&mut self, mt: &MutTy) -> hir::MutTy {
569 ty: self.lower_ty(&mt.ty),
570 mutbl: self.lower_mutability(mt.mutbl),
574 fn lower_bounds(&mut self, bounds: &TyParamBounds) -> hir::TyParamBounds {
575 bounds.iter().map(|bound| self.lower_ty_param_bound(bound)).collect()
578 fn lower_block(&mut self, b: &Block) -> P<hir::Block> {
579 let mut stmts = Vec::new();
582 if let Some((last, rest)) = b.stmts.split_last() {
583 stmts = rest.iter().map(|s| self.lower_stmt(s)).collect::<Vec<_>>();
584 let last = self.lower_stmt(last);
585 if let hir::StmtExpr(e, _) = last.node {
596 rules: self.lower_block_check_mode(&b.rules),
601 fn lower_item_kind(&mut self, i: &ItemKind) -> hir::Item_ {
603 ItemKind::ExternCrate(string) => hir::ItemExternCrate(string),
604 ItemKind::Use(ref view_path) => {
605 hir::ItemUse(self.lower_view_path(view_path))
607 ItemKind::Static(ref t, m, ref e) => {
608 hir::ItemStatic(self.lower_ty(t),
609 self.lower_mutability(m),
612 ItemKind::Const(ref t, ref e) => {
613 hir::ItemConst(self.lower_ty(t), self.lower_expr(e))
615 ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => {
616 hir::ItemFn(self.lower_fn_decl(decl),
617 self.lower_unsafety(unsafety),
618 self.lower_constness(constness),
620 self.lower_generics(generics),
621 self.lower_block(body))
623 ItemKind::Mod(ref m) => hir::ItemMod(self.lower_mod(m)),
624 ItemKind::ForeignMod(ref nm) => hir::ItemForeignMod(self.lower_foreign_mod(nm)),
625 ItemKind::Ty(ref t, ref generics) => {
626 hir::ItemTy(self.lower_ty(t), self.lower_generics(generics))
628 ItemKind::Enum(ref enum_definition, ref generics) => {
629 hir::ItemEnum(hir::EnumDef {
630 variants: enum_definition.variants
632 .map(|x| self.lower_variant(x))
635 self.lower_generics(generics))
637 ItemKind::Struct(ref struct_def, ref generics) => {
638 let struct_def = self.lower_variant_data(struct_def);
639 hir::ItemStruct(struct_def, self.lower_generics(generics))
641 ItemKind::DefaultImpl(unsafety, ref trait_ref) => {
642 hir::ItemDefaultImpl(self.lower_unsafety(unsafety),
643 self.lower_trait_ref(trait_ref))
645 ItemKind::Impl(unsafety, polarity, ref generics, ref ifce, ref ty, ref impl_items) => {
646 let new_impl_items = impl_items.iter()
647 .map(|item| self.lower_impl_item(item))
649 let ifce = ifce.as_ref().map(|trait_ref| self.lower_trait_ref(trait_ref));
650 hir::ItemImpl(self.lower_unsafety(unsafety),
651 self.lower_impl_polarity(polarity),
652 self.lower_generics(generics),
657 ItemKind::Trait(unsafety, ref generics, ref bounds, ref items) => {
658 let bounds = self.lower_bounds(bounds);
659 let items = items.iter().map(|item| self.lower_trait_item(item)).collect();
660 hir::ItemTrait(self.lower_unsafety(unsafety),
661 self.lower_generics(generics),
665 ItemKind::Mac(_) => panic!("Shouldn't still be around"),
669 fn lower_trait_item(&mut self, i: &TraitItem) -> hir::TraitItem {
670 self.with_parent_def(i.id, |this| {
674 attrs: this.lower_attrs(&i.attrs),
676 TraitItemKind::Const(ref ty, ref default) => {
677 hir::ConstTraitItem(this.lower_ty(ty),
678 default.as_ref().map(|x| this.lower_expr(x)))
680 TraitItemKind::Method(ref sig, ref body) => {
681 hir::MethodTraitItem(this.lower_method_sig(sig),
682 body.as_ref().map(|x| this.lower_block(x)))
684 TraitItemKind::Type(ref bounds, ref default) => {
685 hir::TypeTraitItem(this.lower_bounds(bounds),
686 default.as_ref().map(|x| this.lower_ty(x)))
688 TraitItemKind::Macro(..) => panic!("Shouldn't exist any more"),
695 fn lower_impl_item(&mut self, i: &ImplItem) -> hir::ImplItem {
696 self.with_parent_def(i.id, |this| {
700 attrs: this.lower_attrs(&i.attrs),
701 vis: this.lower_visibility(&i.vis),
702 defaultness: this.lower_defaultness(i.defaultness),
704 ImplItemKind::Const(ref ty, ref expr) => {
705 hir::ImplItemKind::Const(this.lower_ty(ty), this.lower_expr(expr))
707 ImplItemKind::Method(ref sig, ref body) => {
708 hir::ImplItemKind::Method(this.lower_method_sig(sig),
709 this.lower_block(body))
711 ImplItemKind::Type(ref ty) => hir::ImplItemKind::Type(this.lower_ty(ty)),
712 ImplItemKind::Macro(..) => panic!("Shouldn't exist any more"),
719 fn lower_mod(&mut self, m: &Mod) -> hir::Mod {
722 item_ids: m.items.iter().map(|x| self.lower_item_id(x)).collect(),
726 fn lower_macro_def(&mut self, m: &MacroDef) -> hir::MacroDef {
729 attrs: self.lower_attrs(&m.attrs),
732 imported_from: m.imported_from.map(|x| x.name),
734 use_locally: m.use_locally,
735 allow_internal_unstable: m.allow_internal_unstable,
736 body: m.body.clone().into(),
740 fn lower_item_id(&mut self, i: &Item) -> hir::ItemId {
741 hir::ItemId { id: i.id }
744 pub fn lower_item(&mut self, i: &Item) -> hir::Item {
745 let node = self.with_parent_def(i.id, |this| {
746 this.lower_item_kind(&i.node)
752 attrs: self.lower_attrs(&i.attrs),
754 vis: self.lower_visibility(&i.vis),
759 fn lower_foreign_item(&mut self, i: &ForeignItem) -> hir::ForeignItem {
760 self.with_parent_def(i.id, |this| {
764 attrs: this.lower_attrs(&i.attrs),
766 ForeignItemKind::Fn(ref fdec, ref generics) => {
767 hir::ForeignItemFn(this.lower_fn_decl(fdec), this.lower_generics(generics))
769 ForeignItemKind::Static(ref t, m) => {
770 hir::ForeignItemStatic(this.lower_ty(t), m)
773 vis: this.lower_visibility(&i.vis),
779 fn lower_method_sig(&mut self, sig: &MethodSig) -> hir::MethodSig {
780 let hir_sig = hir::MethodSig {
781 generics: self.lower_generics(&sig.generics),
783 unsafety: self.lower_unsafety(sig.unsafety),
784 constness: self.lower_constness(sig.constness),
785 decl: self.lower_fn_decl(&sig.decl),
787 // Check for `self: _` and `self: &_`
788 if let Some(SelfKind::Explicit(..)) = sig.decl.get_self().map(|eself| eself.node) {
789 match hir_sig.decl.get_self().map(|eself| eself.node) {
790 Some(hir::SelfKind::Value(..)) | Some(hir::SelfKind::Region(..)) => {
791 self.diagnostic().span_err(sig.decl.inputs[0].ty.span,
792 "the type placeholder `_` is not allowed within types on item signatures");
800 fn lower_unsafety(&mut self, u: Unsafety) -> hir::Unsafety {
802 Unsafety::Unsafe => hir::Unsafety::Unsafe,
803 Unsafety::Normal => hir::Unsafety::Normal,
807 fn lower_constness(&mut self, c: Constness) -> hir::Constness {
809 Constness::Const => hir::Constness::Const,
810 Constness::NotConst => hir::Constness::NotConst,
814 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
816 UnOp::Deref => hir::UnDeref,
817 UnOp::Not => hir::UnNot,
818 UnOp::Neg => hir::UnNeg,
822 fn lower_binop(&mut self, b: BinOp) -> hir::BinOp {
825 BinOpKind::Add => hir::BiAdd,
826 BinOpKind::Sub => hir::BiSub,
827 BinOpKind::Mul => hir::BiMul,
828 BinOpKind::Div => hir::BiDiv,
829 BinOpKind::Rem => hir::BiRem,
830 BinOpKind::And => hir::BiAnd,
831 BinOpKind::Or => hir::BiOr,
832 BinOpKind::BitXor => hir::BiBitXor,
833 BinOpKind::BitAnd => hir::BiBitAnd,
834 BinOpKind::BitOr => hir::BiBitOr,
835 BinOpKind::Shl => hir::BiShl,
836 BinOpKind::Shr => hir::BiShr,
837 BinOpKind::Eq => hir::BiEq,
838 BinOpKind::Lt => hir::BiLt,
839 BinOpKind::Le => hir::BiLe,
840 BinOpKind::Ne => hir::BiNe,
841 BinOpKind::Ge => hir::BiGe,
842 BinOpKind::Gt => hir::BiGt,
848 fn lower_pat(&mut self, p: &Pat) -> P<hir::Pat> {
852 PatKind::Wild => hir::PatKind::Wild,
853 PatKind::Ident(ref binding_mode, pth1, ref sub) => {
854 self.with_parent_def(p.id, |this| {
855 match this.resolver.get_resolution(p.id).map(|d| d.base_def) {
856 // `None` can occur in body-less function signatures
857 None | Some(Def::Local(..)) => {
858 hir::PatKind::Binding(this.lower_binding_mode(binding_mode),
859 respan(pth1.span, pth1.node.name),
860 sub.as_ref().map(|x| this.lower_pat(x)))
862 _ => hir::PatKind::Path(None, hir::Path::from_name(pth1.span,
867 PatKind::Lit(ref e) => hir::PatKind::Lit(self.lower_expr(e)),
868 PatKind::TupleStruct(ref pth, ref pats, ddpos) => {
869 hir::PatKind::TupleStruct(self.lower_path(pth),
870 pats.iter().map(|x| self.lower_pat(x)).collect(),
873 PatKind::Path(ref opt_qself, ref path) => {
874 let opt_qself = opt_qself.as_ref().map(|qself| {
875 hir::QSelf { ty: self.lower_ty(&qself.ty), position: qself.position }
877 hir::PatKind::Path(opt_qself, self.lower_path(path))
879 PatKind::Struct(ref pth, ref fields, etc) => {
880 let pth = self.lower_path(pth);
881 let fs = fields.iter()
885 node: hir::FieldPat {
886 name: f.node.ident.name,
887 pat: self.lower_pat(&f.node.pat),
888 is_shorthand: f.node.is_shorthand,
893 hir::PatKind::Struct(pth, fs, etc)
895 PatKind::Tuple(ref elts, ddpos) => {
896 hir::PatKind::Tuple(elts.iter().map(|x| self.lower_pat(x)).collect(), ddpos)
898 PatKind::Box(ref inner) => hir::PatKind::Box(self.lower_pat(inner)),
899 PatKind::Ref(ref inner, mutbl) => {
900 hir::PatKind::Ref(self.lower_pat(inner), self.lower_mutability(mutbl))
902 PatKind::Range(ref e1, ref e2) => {
903 hir::PatKind::Range(self.lower_expr(e1), self.lower_expr(e2))
905 PatKind::Vec(ref before, ref slice, ref after) => {
906 hir::PatKind::Vec(before.iter().map(|x| self.lower_pat(x)).collect(),
907 slice.as_ref().map(|x| self.lower_pat(x)),
908 after.iter().map(|x| self.lower_pat(x)).collect())
910 PatKind::Mac(_) => panic!("Shouldn't exist here"),
916 fn lower_expr(&mut self, e: &Expr) -> P<hir::Expr> {
921 // Eventually a desugaring for `box EXPR`
922 // (similar to the desugaring above for `in PLACE BLOCK`)
923 // should go here, desugaring
927 // let mut place = BoxPlace::make_place();
928 // let raw_place = Place::pointer(&mut place);
929 // let value = $value;
931 // ::std::ptr::write(raw_place, value);
932 // Boxed::finalize(place)
935 // But for now there are type-inference issues doing that.
936 ExprKind::Box(ref e) => {
937 hir::ExprBox(self.lower_expr(e))
940 // Desugar ExprBox: `in (PLACE) EXPR`
941 ExprKind::InPlace(ref placer, ref value_expr) => {
945 // let mut place = Placer::make_place(p);
946 // let raw_place = Place::pointer(&mut place);
948 // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR ));
949 // InPlace::finalize(place)
951 let placer_expr = self.lower_expr(placer);
952 let value_expr = self.lower_expr(value_expr);
954 let placer_ident = self.str_to_ident("placer");
955 let place_ident = self.str_to_ident("place");
956 let p_ptr_ident = self.str_to_ident("p_ptr");
958 let make_place = ["ops", "Placer", "make_place"];
959 let place_pointer = ["ops", "Place", "pointer"];
960 let move_val_init = ["intrinsics", "move_val_init"];
961 let inplace_finalize = ["ops", "InPlace", "finalize"];
963 let make_call = |this: &mut LoweringContext, p, args| {
964 let path = this.std_path(e.span, p);
965 let path = this.expr_path(path, ThinVec::new());
966 this.expr_call(e.span, path, args)
969 let mk_stmt_let = |this: &mut LoweringContext, bind, expr| {
970 this.stmt_let(e.span, false, bind, expr)
973 let mk_stmt_let_mut = |this: &mut LoweringContext, bind, expr| {
974 this.stmt_let(e.span, true, bind, expr)
977 // let placer = <placer_expr> ;
978 let (s1, placer_binding) = {
979 let placer_expr = self.signal_block_expr(hir_vec![],
982 hir::PopUnstableBlock,
984 mk_stmt_let(self, placer_ident, placer_expr)
987 // let mut place = Placer::make_place(placer);
988 let (s2, place_binding) = {
989 let placer = self.expr_ident(e.span, placer_ident, placer_binding);
990 let call = make_call(self, &make_place, hir_vec![placer]);
991 mk_stmt_let_mut(self, place_ident, call)
994 // let p_ptr = Place::pointer(&mut place);
995 let (s3, p_ptr_binding) = {
996 let agent = self.expr_ident(e.span, place_ident, place_binding);
997 let args = hir_vec![self.expr_mut_addr_of(e.span, agent)];
998 let call = make_call(self, &place_pointer, args);
999 mk_stmt_let(self, p_ptr_ident, call)
1002 // pop_unsafe!(EXPR));
1003 let pop_unsafe_expr = {
1004 let value_expr = self.signal_block_expr(hir_vec![],
1007 hir::PopUnstableBlock,
1009 self.signal_block_expr(hir_vec![],
1012 hir::PopUnsafeBlock(hir::CompilerGenerated),
1017 // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR ));
1018 // InPlace::finalize(place)
1021 let ptr = self.expr_ident(e.span, p_ptr_ident, p_ptr_binding);
1022 let call_move_val_init =
1024 make_call(self, &move_val_init, hir_vec![ptr, pop_unsafe_expr]),
1026 let call_move_val_init = respan(e.span, call_move_val_init);
1028 let place = self.expr_ident(e.span, place_ident, place_binding);
1029 let call = make_call(self, &inplace_finalize, hir_vec![place]);
1030 self.signal_block_expr(hir_vec![call_move_val_init],
1033 hir::PushUnsafeBlock(hir::CompilerGenerated),
1037 return self.signal_block_expr(hir_vec![s1, s2, s3],
1040 hir::PushUnstableBlock,
1044 ExprKind::Vec(ref exprs) => {
1045 hir::ExprVec(exprs.iter().map(|x| self.lower_expr(x)).collect())
1047 ExprKind::Repeat(ref expr, ref count) => {
1048 let expr = self.lower_expr(expr);
1049 let count = self.lower_expr(count);
1050 hir::ExprRepeat(expr, count)
1052 ExprKind::Tup(ref elts) => {
1053 hir::ExprTup(elts.iter().map(|x| self.lower_expr(x)).collect())
1055 ExprKind::Call(ref f, ref args) => {
1056 let f = self.lower_expr(f);
1057 hir::ExprCall(f, args.iter().map(|x| self.lower_expr(x)).collect())
1059 ExprKind::MethodCall(i, ref tps, ref args) => {
1060 let tps = tps.iter().map(|x| self.lower_ty(x)).collect();
1061 let args = args.iter().map(|x| self.lower_expr(x)).collect();
1062 hir::ExprMethodCall(respan(i.span, i.node.name), tps, args)
1064 ExprKind::Binary(binop, ref lhs, ref rhs) => {
1065 let binop = self.lower_binop(binop);
1066 let lhs = self.lower_expr(lhs);
1067 let rhs = self.lower_expr(rhs);
1068 hir::ExprBinary(binop, lhs, rhs)
1070 ExprKind::Unary(op, ref ohs) => {
1071 let op = self.lower_unop(op);
1072 let ohs = self.lower_expr(ohs);
1073 hir::ExprUnary(op, ohs)
1075 ExprKind::Lit(ref l) => hir::ExprLit(P((**l).clone())),
1076 ExprKind::Cast(ref expr, ref ty) => {
1077 let expr = self.lower_expr(expr);
1078 hir::ExprCast(expr, self.lower_ty(ty))
1080 ExprKind::Type(ref expr, ref ty) => {
1081 let expr = self.lower_expr(expr);
1082 hir::ExprType(expr, self.lower_ty(ty))
1084 ExprKind::AddrOf(m, ref ohs) => {
1085 let m = self.lower_mutability(m);
1086 let ohs = self.lower_expr(ohs);
1087 hir::ExprAddrOf(m, ohs)
1089 // More complicated than you might expect because the else branch
1090 // might be `if let`.
1091 ExprKind::If(ref cond, ref blk, ref else_opt) => {
1092 let else_opt = else_opt.as_ref().map(|els| {
1094 ExprKind::IfLet(..) => {
1095 // wrap the if-let expr in a block
1096 let span = els.span;
1097 let els = self.lower_expr(els);
1098 let id = self.next_id();
1099 let blk = P(hir::Block {
1103 rules: hir::DefaultBlock,
1106 self.expr_block(blk, ThinVec::new())
1108 _ => self.lower_expr(els),
1112 hir::ExprIf(self.lower_expr(cond), self.lower_block(blk), else_opt)
1114 ExprKind::While(ref cond, ref body, opt_ident) => {
1115 hir::ExprWhile(self.lower_expr(cond), self.lower_block(body),
1116 self.lower_opt_sp_ident(opt_ident))
1118 ExprKind::Loop(ref body, opt_ident) => {
1119 hir::ExprLoop(self.lower_block(body), self.lower_opt_sp_ident(opt_ident))
1121 ExprKind::Match(ref expr, ref arms) => {
1122 hir::ExprMatch(self.lower_expr(expr),
1123 arms.iter().map(|x| self.lower_arm(x)).collect(),
1124 hir::MatchSource::Normal)
1126 ExprKind::Closure(capture_clause, ref decl, ref body, fn_decl_span) => {
1127 self.with_parent_def(e.id, |this| {
1128 hir::ExprClosure(this.lower_capture_clause(capture_clause),
1129 this.lower_fn_decl(decl),
1130 this.lower_block(body),
1134 ExprKind::Block(ref blk) => hir::ExprBlock(self.lower_block(blk)),
1135 ExprKind::Assign(ref el, ref er) => {
1136 hir::ExprAssign(self.lower_expr(el), self.lower_expr(er))
1138 ExprKind::AssignOp(op, ref el, ref er) => {
1139 hir::ExprAssignOp(self.lower_binop(op),
1140 self.lower_expr(el),
1141 self.lower_expr(er))
1143 ExprKind::Field(ref el, ident) => {
1144 hir::ExprField(self.lower_expr(el), respan(ident.span, ident.node.name))
1146 ExprKind::TupField(ref el, ident) => {
1147 hir::ExprTupField(self.lower_expr(el), ident)
1149 ExprKind::Index(ref el, ref er) => {
1150 hir::ExprIndex(self.lower_expr(el), self.lower_expr(er))
1152 ExprKind::Range(ref e1, ref e2, lims) => {
1153 fn make_struct(this: &mut LoweringContext,
1156 fields: &[(&str, &P<Expr>)]) -> P<hir::Expr> {
1157 let struct_path = this.std_path(ast_expr.span,
1158 &iter::once(&"ops").chain(path)
1160 .collect::<Vec<_>>());
1162 let hir_expr = if fields.len() == 0 {
1163 this.expr_path(struct_path, ast_expr.attrs.clone())
1165 let fields = fields.into_iter().map(|&(s, e)| {
1166 let expr = this.lower_expr(&e);
1167 let signal_block = this.signal_block_expr(hir_vec![],
1170 hir::PopUnstableBlock,
1172 this.field(token::intern(s), signal_block, ast_expr.span)
1174 let attrs = ast_expr.attrs.clone();
1176 this.expr_struct(ast_expr.span, struct_path, fields, None, attrs)
1179 this.signal_block_expr(hir_vec![],
1182 hir::PushUnstableBlock,
1186 use syntax::ast::RangeLimits::*;
1188 return match (e1, e2, lims) {
1189 (&None, &None, HalfOpen) =>
1190 make_struct(self, e, &["RangeFull"], &[]),
1192 (&Some(ref e1), &None, HalfOpen) =>
1193 make_struct(self, e, &["RangeFrom"],
1196 (&None, &Some(ref e2), HalfOpen) =>
1197 make_struct(self, e, &["RangeTo"],
1200 (&Some(ref e1), &Some(ref e2), HalfOpen) =>
1201 make_struct(self, e, &["Range"],
1202 &[("start", e1), ("end", e2)]),
1204 (&None, &Some(ref e2), Closed) =>
1205 make_struct(self, e, &["RangeToInclusive"],
1208 (&Some(ref e1), &Some(ref e2), Closed) =>
1209 make_struct(self, e, &["RangeInclusive", "NonEmpty"],
1210 &[("start", e1), ("end", e2)]),
1212 _ => panic!(self.diagnostic()
1213 .span_fatal(e.span, "inclusive range with no end")),
1216 ExprKind::Path(ref qself, ref path) => {
1217 let hir_qself = qself.as_ref().map(|&QSelf { ref ty, position }| {
1219 ty: self.lower_ty(ty),
1223 hir::ExprPath(hir_qself, self.lower_path(path))
1225 ExprKind::Break(opt_ident) => hir::ExprBreak(self.lower_opt_sp_ident(opt_ident)),
1226 ExprKind::Continue(opt_ident) => hir::ExprAgain(self.lower_opt_sp_ident(opt_ident)),
1227 ExprKind::Ret(ref e) => hir::ExprRet(e.as_ref().map(|x| self.lower_expr(x))),
1228 ExprKind::InlineAsm(InlineAsm {
1238 }) => hir::ExprInlineAsm(hir::InlineAsm {
1239 inputs: inputs.iter().map(|&(ref c, _)| c.clone()).collect(),
1240 outputs: outputs.iter()
1242 hir::InlineAsmOutput {
1243 constraint: out.constraint.clone(),
1245 is_indirect: out.is_indirect,
1250 asm_str_style: asm_str_style,
1251 clobbers: clobbers.clone().into(),
1253 alignstack: alignstack,
1256 }, outputs.iter().map(|out| self.lower_expr(&out.expr)).collect(),
1257 inputs.iter().map(|&(_, ref input)| self.lower_expr(input)).collect()),
1258 ExprKind::Struct(ref path, ref fields, ref maybe_expr) => {
1259 hir::ExprStruct(self.lower_path(path),
1260 fields.iter().map(|x| self.lower_field(x)).collect(),
1261 maybe_expr.as_ref().map(|x| self.lower_expr(x)))
1263 ExprKind::Paren(ref ex) => {
1264 return self.lower_expr(ex).map(|mut ex| {
1265 // include parens in span, but only if it is a super-span.
1266 if e.span.contains(ex.span) {
1269 // merge attributes into the inner expression.
1270 let mut attrs = e.attrs.clone();
1271 attrs.extend::<Vec<_>>(ex.attrs.into());
1277 // Desugar ExprIfLet
1278 // From: `if let <pat> = <sub_expr> <body> [<else_opt>]`
1279 ExprKind::IfLet(ref pat, ref sub_expr, ref body, ref else_opt) => {
1282 // match <sub_expr> {
1284 // [_ if <else_opt_if_cond> => <else_opt_if_body>,]
1285 // _ => [<else_opt> | ()]
1288 // `<pat> => <body>`
1290 let body = self.lower_block(body);
1291 let body_expr = self.expr_block(body, ThinVec::new());
1292 let pat = self.lower_pat(pat);
1293 self.arm(hir_vec![pat], body_expr)
1296 // `[_ if <else_opt_if_cond> => <else_opt_if_body>,]`
1297 let mut else_opt = else_opt.as_ref().map(|e| self.lower_expr(e));
1298 let else_if_arms = {
1299 let mut arms = vec![];
1301 let else_opt_continue = else_opt.and_then(|els| {
1302 els.and_then(|els| {
1305 hir::ExprIf(cond, then, else_opt) => {
1306 let pat_under = self.pat_wild(e.span);
1307 arms.push(hir::Arm {
1309 pats: hir_vec![pat_under],
1311 body: self.expr_block(then, ThinVec::new()),
1313 else_opt.map(|else_opt| (else_opt, true))
1315 _ => Some((P(els), false)),
1319 match else_opt_continue {
1320 Some((e, true)) => {
1323 Some((e, false)) => {
1336 let contains_else_clause = else_opt.is_some();
1338 // `_ => [<else_opt> | ()]`
1340 let pat_under = self.pat_wild(e.span);
1342 else_opt.unwrap_or_else(|| self.expr_tuple(e.span, hir_vec![]));
1343 self.arm(hir_vec![pat_under], else_expr)
1346 let mut arms = Vec::with_capacity(else_if_arms.len() + 2);
1348 arms.extend(else_if_arms);
1349 arms.push(else_arm);
1351 let sub_expr = self.lower_expr(sub_expr);
1352 // add attributes to the outer returned expr node
1353 return self.expr(e.span,
1354 hir::ExprMatch(sub_expr,
1356 hir::MatchSource::IfLetDesugar {
1357 contains_else_clause: contains_else_clause,
1362 // Desugar ExprWhileLet
1363 // From: `[opt_ident]: while let <pat> = <sub_expr> <body>`
1364 ExprKind::WhileLet(ref pat, ref sub_expr, ref body, opt_ident) => {
1367 // [opt_ident]: loop {
1368 // match <sub_expr> {
1374 // `<pat> => <body>`
1376 let body = self.lower_block(body);
1377 let body_expr = self.expr_block(body, ThinVec::new());
1378 let pat = self.lower_pat(pat);
1379 self.arm(hir_vec![pat], body_expr)
1384 let pat_under = self.pat_wild(e.span);
1385 let break_expr = self.expr_break(e.span, ThinVec::new());
1386 self.arm(hir_vec![pat_under], break_expr)
1389 // `match <sub_expr> { ... }`
1390 let arms = hir_vec![pat_arm, break_arm];
1391 let sub_expr = self.lower_expr(sub_expr);
1392 let match_expr = self.expr(e.span,
1393 hir::ExprMatch(sub_expr,
1395 hir::MatchSource::WhileLetDesugar),
1398 // `[opt_ident]: loop { ... }`
1399 let loop_block = self.block_expr(match_expr);
1400 let loop_expr = hir::ExprLoop(loop_block, self.lower_opt_sp_ident(opt_ident));
1401 // add attributes to the outer returned expr node
1402 let attrs = e.attrs.clone();
1403 return P(hir::Expr { id: e.id, node: loop_expr, span: e.span, attrs: attrs });
1406 // Desugar ExprForLoop
1407 // From: `[opt_ident]: for <pat> in <head> <body>`
1408 ExprKind::ForLoop(ref pat, ref head, ref body, opt_ident) => {
1412 // let result = match ::std::iter::IntoIterator::into_iter(<head>) {
1414 // [opt_ident]: loop {
1415 // match ::std::iter::Iterator::next(&mut iter) {
1416 // ::std::option::Option::Some(<pat>) => <body>,
1417 // ::std::option::Option::None => break
1426 let head = self.lower_expr(head);
1428 let iter = self.str_to_ident("iter");
1430 // `::std::option::Option::Some(<pat>) => <body>`
1432 let body_block = self.lower_block(body);
1433 let body_span = body_block.span;
1434 let body_expr = P(hir::Expr {
1436 node: hir::ExprBlock(body_block),
1438 attrs: ThinVec::new(),
1440 let pat = self.lower_pat(pat);
1441 let some_pat = self.pat_some(e.span, pat);
1443 self.arm(hir_vec![some_pat], body_expr)
1446 // `::std::option::Option::None => break`
1448 let break_expr = self.expr_break(e.span, ThinVec::new());
1449 let pat = self.pat_none(e.span);
1450 self.arm(hir_vec![pat], break_expr)
1454 let iter_pat = self.pat_ident_binding_mode(e.span, iter,
1455 hir::BindByValue(hir::MutMutable));
1457 // `match ::std::iter::Iterator::next(&mut iter) { ... }`
1459 let next_path = self.std_path(e.span, &["iter", "Iterator", "next"]);
1460 let iter = self.expr_ident(e.span, iter, iter_pat.id);
1461 let ref_mut_iter = self.expr_mut_addr_of(e.span, iter);
1462 let next_path = self.expr_path(next_path, ThinVec::new());
1463 let next_expr = self.expr_call(e.span, next_path, hir_vec![ref_mut_iter]);
1464 let arms = hir_vec![pat_arm, break_arm];
1467 hir::ExprMatch(next_expr, arms, hir::MatchSource::ForLoopDesugar),
1471 // `[opt_ident]: loop { ... }`
1472 let loop_block = self.block_expr(match_expr);
1473 let loop_expr = hir::ExprLoop(loop_block, self.lower_opt_sp_ident(opt_ident));
1474 let loop_expr = P(hir::Expr {
1478 attrs: ThinVec::new(),
1481 // `mut iter => { ... }`
1482 let iter_arm = self.arm(hir_vec![iter_pat], loop_expr);
1484 // `match ::std::iter::IntoIterator::into_iter(<head>) { ... }`
1485 let into_iter_expr = {
1486 let into_iter_path = self.std_path(e.span,
1487 &["iter", "IntoIterator", "into_iter"]);
1489 let into_iter = self.expr_path(into_iter_path, ThinVec::new());
1490 self.expr_call(e.span, into_iter, hir_vec![head])
1493 let match_expr = self.expr_match(e.span,
1496 hir::MatchSource::ForLoopDesugar);
1498 // `{ let _result = ...; _result }`
1499 // underscore prevents an unused_variables lint if the head diverges
1500 let result_ident = self.str_to_ident("_result");
1501 let (let_stmt, let_stmt_binding) =
1502 self.stmt_let(e.span, false, result_ident, match_expr);
1504 let result = self.expr_ident(e.span, result_ident, let_stmt_binding);
1505 let block = self.block_all(e.span, hir_vec![let_stmt], Some(result));
1506 // add the attributes to the outer returned expr node
1507 return self.expr_block(block, e.attrs.clone());
1510 // Desugar ExprKind::Try
1512 ExprKind::Try(ref sub_expr) => {
1516 // match { Carrier::translate( { <expr> } ) } {
1518 // Err(err) => { return Carrier::from_error(From::from(err)); }
1522 // { Carrier::translate( { <expr> } ) }
1525 let sub_expr = self.lower_expr(sub_expr);
1526 let sub_expr = self.signal_block_expr(hir_vec![],
1529 hir::PopUnstableBlock,
1532 let path = self.std_path(e.span, &["ops", "Carrier", "translate"]);
1533 let path = self.expr_path(path, ThinVec::new());
1534 let call = self.expr_call(e.span, path, hir_vec![sub_expr]);
1536 self.signal_block_expr(hir_vec![],
1539 hir::PushUnstableBlock,
1545 let val_ident = self.str_to_ident("val");
1546 let val_pat = self.pat_ident(e.span, val_ident);
1547 let val_expr = self.expr_ident(e.span, val_ident, val_pat.id);
1548 let ok_pat = self.pat_ok(e.span, val_pat);
1550 self.arm(hir_vec![ok_pat], val_expr)
1553 // Err(err) => { return Carrier::from_error(From::from(err)); }
1555 let err_ident = self.str_to_ident("err");
1556 let err_local = self.pat_ident(e.span, err_ident);
1558 let path = self.std_path(e.span, &["convert", "From", "from"]);
1559 let from = self.expr_path(path, ThinVec::new());
1560 let err_expr = self.expr_ident(e.span, err_ident, err_local.id);
1562 self.expr_call(e.span, from, hir_vec![err_expr])
1564 let from_err_expr = {
1565 let path = self.std_path(e.span, &["ops", "Carrier", "from_error"]);
1566 let from_err = self.expr_path(path, ThinVec::new());
1567 self.expr_call(e.span, from_err, hir_vec![from_expr])
1570 let ret_expr = self.expr(e.span,
1571 hir::Expr_::ExprRet(Some(from_err_expr)),
1573 let ret_stmt = self.stmt_expr(ret_expr);
1574 let block = self.signal_block_stmt(ret_stmt, e.span,
1575 hir::PushUnstableBlock, ThinVec::new());
1577 let err_pat = self.pat_err(e.span, err_local);
1578 self.arm(hir_vec![err_pat], block)
1581 return self.expr_match(e.span, discr, hir_vec![err_arm, ok_arm],
1582 hir::MatchSource::TryDesugar);
1585 ExprKind::Mac(_) => panic!("Shouldn't exist here"),
1588 attrs: e.attrs.clone(),
1592 fn lower_stmt(&mut self, s: &Stmt) -> hir::Stmt {
1594 StmtKind::Local(ref l) => Spanned {
1595 node: hir::StmtDecl(P(Spanned {
1596 node: hir::DeclLocal(self.lower_local(l)),
1601 StmtKind::Item(ref it) => Spanned {
1602 node: hir::StmtDecl(P(Spanned {
1603 node: hir::DeclItem(self.lower_item_id(it)),
1608 StmtKind::Expr(ref e) => {
1610 node: hir::StmtExpr(self.lower_expr(e), s.id),
1614 StmtKind::Semi(ref e) => {
1616 node: hir::StmtSemi(self.lower_expr(e), s.id),
1620 StmtKind::Mac(..) => panic!("Shouldn't exist here"),
1624 fn lower_capture_clause(&mut self, c: CaptureBy) -> hir::CaptureClause {
1626 CaptureBy::Value => hir::CaptureByValue,
1627 CaptureBy::Ref => hir::CaptureByRef,
1631 fn lower_visibility(&mut self, v: &Visibility) -> hir::Visibility {
1633 Visibility::Public => hir::Public,
1634 Visibility::Crate(_) => hir::Visibility::Crate,
1635 Visibility::Restricted { ref path, id } =>
1636 hir::Visibility::Restricted { path: P(self.lower_path(path)), id: id },
1637 Visibility::Inherited => hir::Inherited,
1641 fn lower_defaultness(&mut self, d: Defaultness) -> hir::Defaultness {
1643 Defaultness::Default => hir::Defaultness::Default,
1644 Defaultness::Final => hir::Defaultness::Final,
1648 fn lower_block_check_mode(&mut self, b: &BlockCheckMode) -> hir::BlockCheckMode {
1650 BlockCheckMode::Default => hir::DefaultBlock,
1651 BlockCheckMode::Unsafe(u) => hir::UnsafeBlock(self.lower_unsafe_source(u)),
1655 fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingMode {
1657 BindingMode::ByRef(m) => hir::BindByRef(self.lower_mutability(m)),
1658 BindingMode::ByValue(m) => hir::BindByValue(self.lower_mutability(m)),
1662 fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource {
1664 CompilerGenerated => hir::CompilerGenerated,
1665 UserProvided => hir::UserProvided,
1669 fn lower_impl_polarity(&mut self, i: ImplPolarity) -> hir::ImplPolarity {
1671 ImplPolarity::Positive => hir::ImplPolarity::Positive,
1672 ImplPolarity::Negative => hir::ImplPolarity::Negative,
1676 fn lower_trait_bound_modifier(&mut self, f: TraitBoundModifier) -> hir::TraitBoundModifier {
1678 TraitBoundModifier::None => hir::TraitBoundModifier::None,
1679 TraitBoundModifier::Maybe => hir::TraitBoundModifier::Maybe,
1683 // Helper methods for building HIR.
1685 fn arm(&mut self, pats: hir::HirVec<P<hir::Pat>>, expr: P<hir::Expr>) -> hir::Arm {
1694 fn field(&mut self, name: Name, expr: P<hir::Expr>, span: Span) -> hir::Field {
1705 fn expr_break(&mut self, span: Span, attrs: ThinVec<Attribute>) -> P<hir::Expr> {
1706 self.expr(span, hir::ExprBreak(None), attrs)
1709 fn expr_call(&mut self, span: Span, e: P<hir::Expr>, args: hir::HirVec<P<hir::Expr>>)
1711 self.expr(span, hir::ExprCall(e, args), ThinVec::new())
1714 fn expr_ident(&mut self, span: Span, id: Name, binding: NodeId) -> P<hir::Expr> {
1715 let expr_path = hir::ExprPath(None, self.path_ident(span, id));
1716 let expr = self.expr(span, expr_path, ThinVec::new());
1718 let def = self.resolver.definitions().map(|defs| {
1719 Def::Local(defs.local_def_id(binding), binding)
1720 }).unwrap_or(Def::Err);
1721 self.resolver.record_resolution(expr.id, def);
1726 fn expr_mut_addr_of(&mut self, span: Span, e: P<hir::Expr>) -> P<hir::Expr> {
1727 self.expr(span, hir::ExprAddrOf(hir::MutMutable, e), ThinVec::new())
1730 fn expr_path(&mut self, path: hir::Path, attrs: ThinVec<Attribute>) -> P<hir::Expr> {
1731 let def = self.resolver.resolve_generated_global_path(&path, true);
1732 let expr = self.expr(path.span, hir::ExprPath(None, path), attrs);
1733 self.resolver.record_resolution(expr.id, def);
1737 fn expr_match(&mut self,
1740 arms: hir::HirVec<hir::Arm>,
1741 source: hir::MatchSource)
1743 self.expr(span, hir::ExprMatch(arg, arms, source), ThinVec::new())
1746 fn expr_block(&mut self, b: P<hir::Block>, attrs: ThinVec<Attribute>) -> P<hir::Expr> {
1747 self.expr(b.span, hir::ExprBlock(b), attrs)
1750 fn expr_tuple(&mut self, sp: Span, exprs: hir::HirVec<P<hir::Expr>>) -> P<hir::Expr> {
1751 self.expr(sp, hir::ExprTup(exprs), ThinVec::new())
1754 fn expr_struct(&mut self,
1757 fields: hir::HirVec<hir::Field>,
1758 e: Option<P<hir::Expr>>,
1759 attrs: ThinVec<Attribute>) -> P<hir::Expr> {
1760 let def = self.resolver.resolve_generated_global_path(&path, false);
1761 let expr = self.expr(sp, hir::ExprStruct(path, fields, e), attrs);
1762 self.resolver.record_resolution(expr.id, def);
1766 fn expr(&mut self, span: Span, node: hir::Expr_, attrs: ThinVec<Attribute>) -> P<hir::Expr> {
1775 fn stmt_let(&mut self, sp: Span, mutbl: bool, ident: Name, ex: P<hir::Expr>)
1776 -> (hir::Stmt, NodeId) {
1777 let pat = if mutbl {
1778 self.pat_ident_binding_mode(sp, ident, hir::BindByValue(hir::MutMutable))
1780 self.pat_ident(sp, ident)
1782 let pat_id = pat.id;
1783 let local = P(hir::Local {
1789 attrs: ThinVec::new(),
1791 let decl = respan(sp, hir::DeclLocal(local));
1792 (respan(sp, hir::StmtDecl(P(decl), self.next_id())), pat_id)
1795 // Turns `<expr>` into `<expr>;`, note that this produces a StmtSemi, not a
1797 fn stmt_expr(&self, expr: P<hir::Expr>) -> hir::Stmt {
1800 node: hir::StmtSemi(expr, self.next_id()),
1804 fn block_expr(&mut self, expr: P<hir::Expr>) -> P<hir::Block> {
1805 self.block_all(expr.span, hir::HirVec::new(), Some(expr))
1808 fn block_all(&mut self, span: Span, stmts: hir::HirVec<hir::Stmt>, expr: Option<P<hir::Expr>>)
1814 rules: hir::DefaultBlock,
1819 fn pat_ok(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
1820 let path = self.std_path(span, &["result", "Result", "Ok"]);
1821 self.pat_enum(span, path, hir_vec![pat])
1824 fn pat_err(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
1825 let path = self.std_path(span, &["result", "Result", "Err"]);
1826 self.pat_enum(span, path, hir_vec![pat])
1829 fn pat_some(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
1830 let path = self.std_path(span, &["option", "Option", "Some"]);
1831 self.pat_enum(span, path, hir_vec![pat])
1834 fn pat_none(&mut self, span: Span) -> P<hir::Pat> {
1835 let path = self.std_path(span, &["option", "Option", "None"]);
1836 self.pat_enum(span, path, hir_vec![])
1839 fn pat_enum(&mut self, span: Span, path: hir::Path, subpats: hir::HirVec<P<hir::Pat>>)
1841 let def = self.resolver.resolve_generated_global_path(&path, true);
1842 let pt = if subpats.is_empty() {
1843 hir::PatKind::Path(None, path)
1845 hir::PatKind::TupleStruct(path, subpats, None)
1847 let pat = self.pat(span, pt);
1848 self.resolver.record_resolution(pat.id, def);
1852 fn pat_ident(&mut self, span: Span, name: Name) -> P<hir::Pat> {
1853 self.pat_ident_binding_mode(span, name, hir::BindByValue(hir::MutImmutable))
1856 fn pat_ident_binding_mode(&mut self, span: Span, name: Name, bm: hir::BindingMode)
1858 let pat_ident = hir::PatKind::Binding(bm,
1865 let pat = self.pat(span, pat_ident);
1867 let parent_def = self.parent_def;
1868 let def = self.resolver.definitions().map(|defs| {
1869 let def_path_data = DefPathData::Binding(name.as_str());
1870 let def_index = defs.create_def_with_parent(parent_def, pat.id, def_path_data);
1871 Def::Local(DefId::local(def_index), pat.id)
1872 }).unwrap_or(Def::Err);
1873 self.resolver.record_resolution(pat.id, def);
1878 fn pat_wild(&mut self, span: Span) -> P<hir::Pat> {
1879 self.pat(span, hir::PatKind::Wild)
1882 fn pat(&mut self, span: Span, pat: hir::PatKind) -> P<hir::Pat> {
1890 fn path_ident(&mut self, span: Span, id: Name) -> hir::Path {
1891 self.path(span, vec![id])
1894 fn path(&mut self, span: Span, strs: Vec<Name>) -> hir::Path {
1895 self.path_all(span, false, strs, hir::HirVec::new(), hir::HirVec::new(), hir::HirVec::new())
1898 fn path_global(&mut self, span: Span, strs: Vec<Name>) -> hir::Path {
1899 self.path_all(span, true, strs, hir::HirVec::new(), hir::HirVec::new(), hir::HirVec::new())
1902 fn path_all(&mut self,
1905 mut names: Vec<Name>,
1906 lifetimes: hir::HirVec<hir::Lifetime>,
1907 types: hir::HirVec<P<hir::Ty>>,
1908 bindings: hir::HirVec<hir::TypeBinding>)
1910 let last_identifier = names.pop().unwrap();
1911 let mut segments: Vec<hir::PathSegment> = names.into_iter().map(|name| {
1914 parameters: hir::PathParameters::none(),
1918 segments.push(hir::PathSegment {
1919 name: last_identifier,
1920 parameters: hir::AngleBracketedParameters(hir::AngleBracketedParameterData {
1921 lifetimes: lifetimes,
1929 segments: segments.into(),
1933 fn std_path_components(&mut self, components: &[&str]) -> Vec<Name> {
1934 let mut v = Vec::new();
1935 if let Some(s) = self.crate_root {
1936 v.push(token::intern(s));
1938 v.extend(components.iter().map(|s| token::intern(s)));
1942 // Given suffix ["b","c","d"], returns path `::std::b::c::d` when
1943 // `fld.cx.use_std`, and `::core::b::c::d` otherwise.
1944 fn std_path(&mut self, span: Span, components: &[&str]) -> hir::Path {
1945 let idents = self.std_path_components(components);
1946 self.path_global(span, idents)
1949 fn signal_block_expr(&mut self,
1950 stmts: hir::HirVec<hir::Stmt>,
1953 rule: hir::BlockCheckMode,
1954 attrs: ThinVec<Attribute>)
1956 let id = self.next_id();
1957 let block = P(hir::Block {
1964 self.expr_block(block, attrs)
1967 fn signal_block_stmt(&mut self,
1970 rule: hir::BlockCheckMode,
1971 attrs: ThinVec<Attribute>)
1973 let id = self.next_id();
1974 let block = P(hir::Block {
1978 stmts: hir_vec![stmt],
1981 self.expr_block(block, attrs)