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 // is 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 one of the node's id to a fresh one.
32 // Lowering must be reproducable (the compiler only lowers once, but tools and
33 // custom lints may lower an AST node to a HIR node to interact with the
34 // compiler). The only interesting bit of this is ids - if you lower an AST node
35 // and create new HIR nodes with fresh ids, when re-lowering the same node, you
36 // must ensure you get the same ids! To do this, we keep track of the next id
37 // when we translate a node which requires new ids. By checking this cache and
38 // using node ids starting with the cached id, we ensure ids are reproducible.
39 // To use this system, you just need to hold on to a CachedIdSetter object
40 // whilst lowering. This is an RAII object that takes care of setting and
41 // restoring the cached id, etc.
43 // This whole system relies on node ids being incremented one at a time and
44 // all increments being for lowering. This means that you should not call any
45 // non-lowering function which will use new node ids.
47 // Spans are used for error messages and for tools to map semantics back to
48 // source code. It is therefore not as important with spans as ids to be strict
49 // about use (you can't break the compiler by screwing up a span). Obviously, a
50 // HIR node can only have a single span. But multiple nodes can have the same
51 // span and spans don't need to be kept in order, etc. Where code is preserved
52 // by lowering, it should have the same span as in the AST. Where HIR nodes are
53 // new it is probably best to give a span for the whole AST node being lowered.
54 // All nodes should have real spans, don't use dummy spans. Tools are likely to
55 // get confused if the spans from leaf AST nodes occur in multiple places
56 // in the HIR, especially for multiple identifiers.
60 use std::collections::HashMap;
64 use syntax::codemap::{respan, Spanned, Span};
65 use syntax::owned_slice::OwnedSlice;
66 use syntax::parse::token::{self, str_to_ident};
67 use syntax::std_inject;
69 use std::cell::{Cell, RefCell};
71 pub struct LoweringContext<'a> {
72 crate_root: Option<&'static str>,
73 // Map AST ids to ids used for expanded nodes.
74 id_cache: RefCell<HashMap<NodeId, NodeId>>,
75 // Use if there are no cached ids for the current node.
76 id_assigner: &'a NodeIdAssigner,
77 // 0 == no cached id. Must be incremented to align with previous id
82 impl<'a, 'hir> LoweringContext<'a> {
83 pub fn new(id_assigner: &'a NodeIdAssigner, c: &Crate) -> LoweringContext<'a> {
84 let crate_root = if std_inject::no_core(c) {
86 } else if std_inject::no_std(c) {
93 crate_root: crate_root,
94 id_cache: RefCell::new(HashMap::new()),
95 id_assigner: id_assigner,
96 cached_id: Cell::new(0),
100 fn next_id(&self) -> NodeId {
101 let cached = self.cached_id.get();
103 return self.id_assigner.next_node_id()
106 self.cached_id.set(cached + 1);
111 pub fn lower_view_path(_lctx: &LoweringContext, view_path: &ViewPath) -> P<hir::ViewPath> {
113 node: match view_path.node {
114 ViewPathSimple(ident, ref path) => {
115 hir::ViewPathSimple(ident.name, lower_path(_lctx, path))
117 ViewPathGlob(ref path) => {
118 hir::ViewPathGlob(lower_path(_lctx, path))
120 ViewPathList(ref path, ref path_list_idents) => {
121 hir::ViewPathList(lower_path(_lctx, path),
122 path_list_idents.iter().map(|path_list_ident| {
124 node: match path_list_ident.node {
125 PathListIdent { id, name, rename } =>
129 rename: rename.map(|x| x.name),
131 PathListMod { id, rename } =>
134 rename: rename.map(|x| x.name)
137 span: path_list_ident.span
142 span: view_path.span,
146 pub fn lower_arm(_lctx: &LoweringContext, arm: &Arm) -> hir::Arm {
148 attrs: arm.attrs.clone(),
149 pats: arm.pats.iter().map(|x| lower_pat(_lctx, x)).collect(),
150 guard: arm.guard.as_ref().map(|ref x| lower_expr(_lctx, x)),
151 body: lower_expr(_lctx, &arm.body),
155 pub fn lower_decl(_lctx: &LoweringContext, d: &Decl) -> P<hir::Decl> {
157 DeclLocal(ref l) => P(Spanned {
158 node: hir::DeclLocal(lower_local(_lctx, l)),
161 DeclItem(ref it) => P(Spanned {
162 node: hir::DeclItem(lower_item(_lctx, it)),
168 pub fn lower_ty_binding(_lctx: &LoweringContext, b: &TypeBinding) -> P<hir::TypeBinding> {
169 P(hir::TypeBinding { id: b.id, name: b.ident.name, ty: lower_ty(_lctx, &b.ty), span: b.span })
172 pub fn lower_ty(_lctx: &LoweringContext, t: &Ty) -> P<hir::Ty> {
176 TyInfer => hir::TyInfer,
177 TyVec(ref ty) => hir::TyVec(lower_ty(_lctx, ty)),
178 TyPtr(ref mt) => hir::TyPtr(lower_mt(_lctx, mt)),
179 TyRptr(ref region, ref mt) => {
180 hir::TyRptr(lower_opt_lifetime(_lctx, region), lower_mt(_lctx, mt))
183 hir::TyBareFn(P(hir::BareFnTy {
184 lifetimes: lower_lifetime_defs(_lctx, &f.lifetimes),
185 unsafety: lower_unsafety(_lctx, f.unsafety),
187 decl: lower_fn_decl(_lctx, &f.decl),
190 TyTup(ref tys) => hir::TyTup(tys.iter().map(|ty| lower_ty(_lctx, ty)).collect()),
191 TyParen(ref ty) => hir::TyParen(lower_ty(_lctx, ty)),
192 TyPath(ref qself, ref path) => {
193 let qself = qself.as_ref().map(|&QSelf { ref ty, position }| {
195 ty: lower_ty(_lctx, ty),
199 hir::TyPath(qself, lower_path(_lctx, path))
201 TyObjectSum(ref ty, ref bounds) => {
202 hir::TyObjectSum(lower_ty(_lctx, ty),
203 lower_bounds(_lctx, bounds))
205 TyFixedLengthVec(ref ty, ref e) => {
206 hir::TyFixedLengthVec(lower_ty(_lctx, ty), lower_expr(_lctx, e))
208 TyTypeof(ref expr) => {
209 hir::TyTypeof(lower_expr(_lctx, expr))
211 TyPolyTraitRef(ref bounds) => {
212 hir::TyPolyTraitRef(bounds.iter().map(|b| lower_ty_param_bound(_lctx, b)).collect())
214 TyMac(_) => panic!("TyMac should have been expanded by now."),
220 pub fn lower_foreign_mod(_lctx: &LoweringContext, fm: &ForeignMod) -> hir::ForeignMod {
223 items: fm.items.iter().map(|x| lower_foreign_item(_lctx, x)).collect(),
227 pub fn lower_variant(_lctx: &LoweringContext, v: &Variant) -> P<hir::Variant> {
229 node: hir::Variant_ {
231 name: v.node.name.name,
232 attrs: v.node.attrs.clone(),
233 kind: match v.node.kind {
234 TupleVariantKind(ref variant_args) => {
235 hir::TupleVariantKind(variant_args.iter().map(|ref x|
236 lower_variant_arg(_lctx, x)).collect())
238 StructVariantKind(ref struct_def) => {
239 hir::StructVariantKind(lower_struct_def(_lctx, struct_def))
242 disr_expr: v.node.disr_expr.as_ref().map(|e| lower_expr(_lctx, e)),
248 pub fn lower_path(_lctx: &LoweringContext, p: &Path) -> hir::Path {
251 segments: p.segments.iter().map(|&PathSegment {identifier, ref parameters}|
253 identifier: identifier,
254 parameters: lower_path_parameters(_lctx, parameters),
260 pub fn lower_path_parameters(_lctx: &LoweringContext,
261 path_parameters: &PathParameters)
262 -> hir::PathParameters {
263 match *path_parameters {
264 AngleBracketedParameters(ref data) =>
265 hir::AngleBracketedParameters(lower_angle_bracketed_parameter_data(_lctx, data)),
266 ParenthesizedParameters(ref data) =>
267 hir::ParenthesizedParameters(lower_parenthesized_parameter_data(_lctx, data)),
271 pub fn lower_angle_bracketed_parameter_data(_lctx: &LoweringContext,
272 data: &AngleBracketedParameterData)
273 -> hir::AngleBracketedParameterData {
274 let &AngleBracketedParameterData { ref lifetimes, ref types, ref bindings } = data;
275 hir::AngleBracketedParameterData {
276 lifetimes: lower_lifetimes(_lctx, lifetimes),
277 types: types.iter().map(|ty| lower_ty(_lctx, ty)).collect(),
278 bindings: bindings.iter().map(|b| lower_ty_binding(_lctx, b)).collect(),
282 pub fn lower_parenthesized_parameter_data(_lctx: &LoweringContext,
283 data: &ParenthesizedParameterData)
284 -> hir::ParenthesizedParameterData {
285 let &ParenthesizedParameterData { ref inputs, ref output, span } = data;
286 hir::ParenthesizedParameterData {
287 inputs: inputs.iter().map(|ty| lower_ty(_lctx, ty)).collect(),
288 output: output.as_ref().map(|ty| lower_ty(_lctx, ty)),
293 pub fn lower_local(_lctx: &LoweringContext, l: &Local) -> P<hir::Local> {
296 ty: l.ty.as_ref().map(|t| lower_ty(_lctx, t)),
297 pat: lower_pat(_lctx, &l.pat),
298 init: l.init.as_ref().map(|e| lower_expr(_lctx, e)),
303 pub fn lower_explicit_self_underscore(_lctx: &LoweringContext,
305 -> hir::ExplicitSelf_ {
307 SelfStatic => hir::SelfStatic,
308 SelfValue(v) => hir::SelfValue(v.name),
309 SelfRegion(ref lifetime, m, ident) => {
310 hir::SelfRegion(lower_opt_lifetime(_lctx, lifetime),
311 lower_mutability(_lctx, m),
314 SelfExplicit(ref typ, ident) => {
315 hir::SelfExplicit(lower_ty(_lctx, typ), ident.name)
320 pub fn lower_mutability(_lctx: &LoweringContext, m: Mutability) -> hir::Mutability {
322 MutMutable => hir::MutMutable,
323 MutImmutable => hir::MutImmutable,
327 pub fn lower_explicit_self(_lctx: &LoweringContext, s: &ExplicitSelf) -> hir::ExplicitSelf {
328 Spanned { node: lower_explicit_self_underscore(_lctx, &s.node), span: s.span }
331 pub fn lower_arg(_lctx: &LoweringContext, arg: &Arg) -> hir::Arg {
332 hir::Arg { id: arg.id, pat: lower_pat(_lctx, &arg.pat), ty: lower_ty(_lctx, &arg.ty) }
335 pub fn lower_fn_decl(_lctx: &LoweringContext, decl: &FnDecl) -> P<hir::FnDecl> {
337 inputs: decl.inputs.iter().map(|x| lower_arg(_lctx, x)).collect(),
338 output: match decl.output {
339 Return(ref ty) => hir::Return(lower_ty(_lctx, ty)),
340 DefaultReturn(span) => hir::DefaultReturn(span),
341 NoReturn(span) => hir::NoReturn(span),
343 variadic: decl.variadic,
347 pub fn lower_ty_param_bound(_lctx: &LoweringContext, tpb: &TyParamBound) -> hir::TyParamBound {
349 TraitTyParamBound(ref ty, modifier) => {
350 hir::TraitTyParamBound(lower_poly_trait_ref(_lctx, ty),
351 lower_trait_bound_modifier(_lctx, modifier))
353 RegionTyParamBound(ref lifetime) => {
354 hir::RegionTyParamBound(lower_lifetime(_lctx, lifetime))
359 pub fn lower_ty_param(_lctx: &LoweringContext, tp: &TyParam) -> hir::TyParam {
363 bounds: lower_bounds(_lctx, &tp.bounds),
364 default: tp.default.as_ref().map(|x| lower_ty(_lctx, x)),
369 pub fn lower_ty_params(_lctx: &LoweringContext,
370 tps: &OwnedSlice<TyParam>)
371 -> OwnedSlice<hir::TyParam> {
372 tps.iter().map(|tp| lower_ty_param(_lctx, tp)).collect()
375 pub fn lower_lifetime(_lctx: &LoweringContext, l: &Lifetime) -> hir::Lifetime {
376 hir::Lifetime { id: l.id, name: l.name, span: l.span }
379 pub fn lower_lifetime_def(_lctx: &LoweringContext, l: &LifetimeDef) -> hir::LifetimeDef {
381 lifetime: lower_lifetime(_lctx, &l.lifetime),
382 bounds: lower_lifetimes(_lctx, &l.bounds)
386 pub fn lower_lifetimes(_lctx: &LoweringContext, lts: &Vec<Lifetime>) -> Vec<hir::Lifetime> {
387 lts.iter().map(|l| lower_lifetime(_lctx, l)).collect()
390 pub fn lower_lifetime_defs(_lctx: &LoweringContext,
391 lts: &Vec<LifetimeDef>)
392 -> Vec<hir::LifetimeDef> {
393 lts.iter().map(|l| lower_lifetime_def(_lctx, l)).collect()
396 pub fn lower_opt_lifetime(_lctx: &LoweringContext,
397 o_lt: &Option<Lifetime>)
398 -> Option<hir::Lifetime> {
399 o_lt.as_ref().map(|lt| lower_lifetime(_lctx, lt))
402 pub fn lower_generics(_lctx: &LoweringContext, g: &Generics) -> hir::Generics {
404 ty_params: lower_ty_params(_lctx, &g.ty_params),
405 lifetimes: lower_lifetime_defs(_lctx, &g.lifetimes),
406 where_clause: lower_where_clause(_lctx, &g.where_clause),
410 pub fn lower_where_clause(_lctx: &LoweringContext, wc: &WhereClause) -> hir::WhereClause {
413 predicates: wc.predicates.iter().map(|predicate|
414 lower_where_predicate(_lctx, predicate)).collect(),
418 pub fn lower_where_predicate(_lctx: &LoweringContext,
419 pred: &WherePredicate)
420 -> hir::WherePredicate {
422 WherePredicate::BoundPredicate(WhereBoundPredicate{ ref bound_lifetimes,
426 hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
427 bound_lifetimes: lower_lifetime_defs(_lctx, bound_lifetimes),
428 bounded_ty: lower_ty(_lctx, bounded_ty),
429 bounds: bounds.iter().map(|x| lower_ty_param_bound(_lctx, x)).collect(),
433 WherePredicate::RegionPredicate(WhereRegionPredicate{ ref lifetime,
436 hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
438 lifetime: lower_lifetime(_lctx, lifetime),
439 bounds: bounds.iter().map(|bound| lower_lifetime(_lctx, bound)).collect()
442 WherePredicate::EqPredicate(WhereEqPredicate{ id,
446 hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
448 path: lower_path(_lctx, path),
449 ty:lower_ty(_lctx, ty),
456 pub fn lower_struct_def(_lctx: &LoweringContext, sd: &StructDef) -> P<hir::StructDef> {
458 fields: sd.fields.iter().map(|f| lower_struct_field(_lctx, f)).collect(),
463 pub fn lower_trait_ref(_lctx: &LoweringContext, p: &TraitRef) -> hir::TraitRef {
464 hir::TraitRef { path: lower_path(_lctx, &p.path), ref_id: p.ref_id }
467 pub fn lower_poly_trait_ref(_lctx: &LoweringContext, p: &PolyTraitRef) -> hir::PolyTraitRef {
469 bound_lifetimes: lower_lifetime_defs(_lctx, &p.bound_lifetimes),
470 trait_ref: lower_trait_ref(_lctx, &p.trait_ref),
475 pub fn lower_struct_field(_lctx: &LoweringContext, f: &StructField) -> hir::StructField {
477 node: hir::StructField_ {
479 kind: lower_struct_field_kind(_lctx, &f.node.kind),
480 ty: lower_ty(_lctx, &f.node.ty),
481 attrs: f.node.attrs.clone(),
487 pub fn lower_field(_lctx: &LoweringContext, f: &Field) -> hir::Field {
489 name: respan(f.ident.span, f.ident.node.name),
490 expr: lower_expr(_lctx, &f.expr), span: f.span
494 pub fn lower_mt(_lctx: &LoweringContext, mt: &MutTy) -> hir::MutTy {
495 hir::MutTy { ty: lower_ty(_lctx, &mt.ty), mutbl: lower_mutability(_lctx, mt.mutbl) }
498 pub fn lower_opt_bounds(_lctx: &LoweringContext, b: &Option<OwnedSlice<TyParamBound>>)
499 -> Option<OwnedSlice<hir::TyParamBound>> {
500 b.as_ref().map(|ref bounds| lower_bounds(_lctx, bounds))
503 fn lower_bounds(_lctx: &LoweringContext, bounds: &TyParamBounds) -> hir::TyParamBounds {
504 bounds.iter().map(|bound| lower_ty_param_bound(_lctx, bound)).collect()
507 fn lower_variant_arg(_lctx: &LoweringContext, va: &VariantArg) -> hir::VariantArg {
508 hir::VariantArg { id: va.id, ty: lower_ty(_lctx, &va.ty) }
511 pub fn lower_block(_lctx: &LoweringContext, b: &Block) -> P<hir::Block> {
514 stmts: b.stmts.iter().map(|s| lower_stmt(_lctx, s)).collect(),
515 expr: b.expr.as_ref().map(|ref x| lower_expr(_lctx, x)),
516 rules: lower_block_check_mode(_lctx, &b.rules),
521 pub fn lower_item_underscore(_lctx: &LoweringContext, i: &Item_) -> hir::Item_ {
523 ItemExternCrate(string) => hir::ItemExternCrate(string),
524 ItemUse(ref view_path) => {
525 hir::ItemUse(lower_view_path(_lctx, view_path))
527 ItemStatic(ref t, m, ref e) => {
528 hir::ItemStatic(lower_ty(_lctx, t), lower_mutability(_lctx, m), lower_expr(_lctx, e))
530 ItemConst(ref t, ref e) => {
531 hir::ItemConst(lower_ty(_lctx, t), lower_expr(_lctx, e))
533 ItemFn(ref decl, unsafety, constness, abi, ref generics, ref body) => {
535 lower_fn_decl(_lctx, decl),
536 lower_unsafety(_lctx, unsafety),
537 lower_constness(_lctx, constness),
539 lower_generics(_lctx, generics),
540 lower_block(_lctx, body)
543 ItemMod(ref m) => hir::ItemMod(lower_mod(_lctx, m)),
544 ItemForeignMod(ref nm) => hir::ItemForeignMod(lower_foreign_mod(_lctx, nm)),
545 ItemTy(ref t, ref generics) => {
546 hir::ItemTy(lower_ty(_lctx, t), lower_generics(_lctx, generics))
548 ItemEnum(ref enum_definition, ref generics) => {
551 variants: enum_definition.variants.iter().map(|x| {
552 lower_variant(_lctx, x)
555 lower_generics(_lctx, generics))
557 ItemStruct(ref struct_def, ref generics) => {
558 let struct_def = lower_struct_def(_lctx, struct_def);
559 hir::ItemStruct(struct_def, lower_generics(_lctx, generics))
561 ItemDefaultImpl(unsafety, ref trait_ref) => {
562 hir::ItemDefaultImpl(lower_unsafety(_lctx, unsafety), lower_trait_ref(_lctx, trait_ref))
564 ItemImpl(unsafety, polarity, ref generics, ref ifce, ref ty, ref impl_items) => {
566 impl_items.iter().map(|item| lower_impl_item(_lctx, item)).collect();
567 let ifce = ifce.as_ref().map(|trait_ref| lower_trait_ref(_lctx, trait_ref));
568 hir::ItemImpl(lower_unsafety(_lctx, unsafety),
569 lower_impl_polarity(_lctx, polarity),
570 lower_generics(_lctx, generics),
575 ItemTrait(unsafety, ref generics, ref bounds, ref items) => {
576 let bounds = lower_bounds(_lctx, bounds);
577 let items = items.iter().map(|item| lower_trait_item(_lctx, item)).collect();
578 hir::ItemTrait(lower_unsafety(_lctx, unsafety),
579 lower_generics(_lctx, generics),
583 ItemMac(_) => panic!("Shouldn't still be around"),
587 pub fn lower_trait_item(_lctx: &LoweringContext, i: &TraitItem) -> P<hir::TraitItem> {
591 attrs: i.attrs.clone(),
593 ConstTraitItem(ref ty, ref default) => {
594 hir::ConstTraitItem(lower_ty(_lctx, ty),
595 default.as_ref().map(|x| lower_expr(_lctx, x)))
597 MethodTraitItem(ref sig, ref body) => {
598 hir::MethodTraitItem(lower_method_sig(_lctx, sig),
599 body.as_ref().map(|x| lower_block(_lctx, x)))
601 TypeTraitItem(ref bounds, ref default) => {
602 hir::TypeTraitItem(lower_bounds(_lctx, bounds),
603 default.as_ref().map(|x| lower_ty(_lctx, x)))
610 pub fn lower_impl_item(_lctx: &LoweringContext, i: &ImplItem) -> P<hir::ImplItem> {
614 attrs: i.attrs.clone(),
615 vis: lower_visibility(_lctx, i.vis),
617 ConstImplItem(ref ty, ref expr) => {
618 hir::ConstImplItem(lower_ty(_lctx, ty), lower_expr(_lctx, expr))
620 MethodImplItem(ref sig, ref body) => {
621 hir::MethodImplItem(lower_method_sig(_lctx, sig),
622 lower_block(_lctx, body))
624 TypeImplItem(ref ty) => hir::TypeImplItem(lower_ty(_lctx, ty)),
625 MacImplItem(..) => panic!("Shouldn't exist any more"),
631 pub fn lower_mod(_lctx: &LoweringContext, m: &Mod) -> hir::Mod {
632 hir::Mod { inner: m.inner, items: m.items.iter().map(|x| lower_item(_lctx, x)).collect() }
635 pub fn lower_crate(_lctx: &LoweringContext, c: &Crate) -> hir::Crate {
637 module: lower_mod(_lctx, &c.module),
638 attrs: c.attrs.clone(),
639 config: c.config.clone(),
641 exported_macros: c.exported_macros.iter().map(|m| lower_macro_def(_lctx, m)).collect(),
645 pub fn lower_macro_def(_lctx: &LoweringContext, m: &MacroDef) -> hir::MacroDef {
648 attrs: m.attrs.clone(),
651 imported_from: m.imported_from.map(|x| x.name),
653 use_locally: m.use_locally,
654 allow_internal_unstable: m.allow_internal_unstable,
655 body: m.body.clone(),
659 // fold one item into possibly many items
660 pub fn lower_item(_lctx: &LoweringContext, i: &Item) -> P<hir::Item> {
661 P(lower_item_simple(_lctx, i))
664 // fold one item into exactly one item
665 pub fn lower_item_simple(_lctx: &LoweringContext, i: &Item) -> hir::Item {
666 let node = lower_item_underscore(_lctx, &i.node);
671 attrs: i.attrs.clone(),
673 vis: lower_visibility(_lctx, i.vis),
678 pub fn lower_foreign_item(_lctx: &LoweringContext, i: &ForeignItem) -> P<hir::ForeignItem> {
682 attrs: i.attrs.clone(),
684 ForeignItemFn(ref fdec, ref generics) => {
685 hir::ForeignItemFn(lower_fn_decl(_lctx, fdec), lower_generics(_lctx, generics))
687 ForeignItemStatic(ref t, m) => {
688 hir::ForeignItemStatic(lower_ty(_lctx, t), m)
691 vis: lower_visibility(_lctx, i.vis),
696 pub fn lower_method_sig(_lctx: &LoweringContext, sig: &MethodSig) -> hir::MethodSig {
698 generics: lower_generics(_lctx, &sig.generics),
700 explicit_self: lower_explicit_self(_lctx, &sig.explicit_self),
701 unsafety: lower_unsafety(_lctx, sig.unsafety),
702 constness: lower_constness(_lctx, sig.constness),
703 decl: lower_fn_decl(_lctx, &sig.decl),
707 pub fn lower_unsafety(_lctx: &LoweringContext, u: Unsafety) -> hir::Unsafety {
709 Unsafety::Unsafe => hir::Unsafety::Unsafe,
710 Unsafety::Normal => hir::Unsafety::Normal,
714 pub fn lower_constness(_lctx: &LoweringContext, c: Constness) -> hir::Constness {
716 Constness::Const => hir::Constness::Const,
717 Constness::NotConst => hir::Constness::NotConst,
721 pub fn lower_unop(_lctx: &LoweringContext, u: UnOp) -> hir::UnOp {
723 UnDeref => hir::UnDeref,
729 pub fn lower_binop(_lctx: &LoweringContext, b: BinOp) -> hir::BinOp {
739 BiBitXor => hir::BiBitXor,
740 BiBitAnd => hir::BiBitAnd,
741 BiBitOr => hir::BiBitOr,
755 pub fn lower_pat(_lctx: &LoweringContext, p: &Pat) -> P<hir::Pat> {
759 PatWild(k) => hir::PatWild(lower_pat_wild_kind(_lctx, k)),
760 PatIdent(ref binding_mode, pth1, ref sub) => {
761 hir::PatIdent(lower_binding_mode(_lctx, binding_mode),
763 sub.as_ref().map(|x| lower_pat(_lctx, x)))
765 PatLit(ref e) => hir::PatLit(lower_expr(_lctx, e)),
766 PatEnum(ref pth, ref pats) => {
767 hir::PatEnum(lower_path(_lctx, pth),
769 .map(|pats| pats.iter().map(|x| lower_pat(_lctx, x)).collect()))
771 PatQPath(ref qself, ref pth) => {
772 let qself = hir::QSelf {
773 ty: lower_ty(_lctx, &qself.ty),
774 position: qself.position,
776 hir::PatQPath(qself, lower_path(_lctx, pth))
778 PatStruct(ref pth, ref fields, etc) => {
779 let pth = lower_path(_lctx, pth);
780 let fs = fields.iter().map(|f| {
781 Spanned { span: f.span,
782 node: hir::FieldPat {
783 name: f.node.ident.name,
784 pat: lower_pat(_lctx, &f.node.pat),
785 is_shorthand: f.node.is_shorthand,
788 hir::PatStruct(pth, fs, etc)
790 PatTup(ref elts) => hir::PatTup(elts.iter().map(|x| lower_pat(_lctx, x)).collect()),
791 PatBox(ref inner) => hir::PatBox(lower_pat(_lctx, inner)),
792 PatRegion(ref inner, mutbl) => hir::PatRegion(lower_pat(_lctx, inner),
793 lower_mutability(_lctx, mutbl)),
794 PatRange(ref e1, ref e2) => {
795 hir::PatRange(lower_expr(_lctx, e1), lower_expr(_lctx, e2))
797 PatVec(ref before, ref slice, ref after) => {
798 hir::PatVec(before.iter().map(|x| lower_pat(_lctx, x)).collect(),
799 slice.as_ref().map(|x| lower_pat(_lctx, x)),
800 after.iter().map(|x| lower_pat(_lctx, x)).collect())
802 PatMac(_) => panic!("Shouldn't exist here"),
808 // RAII utility for setting and unsetting the cached id.
809 struct CachedIdSetter<'a> {
811 lctx: &'a LoweringContext<'a>,
814 impl<'a> CachedIdSetter<'a> {
815 fn new(lctx: &'a LoweringContext, expr_id: NodeId) -> CachedIdSetter<'a> {
816 let id_cache: &mut HashMap<_, _> = &mut lctx.id_cache.borrow_mut();
818 if id_cache.contains_key(&expr_id) {
819 let cached_id = lctx.cached_id.get();
821 // We're entering a node where we need to track ids, but are not
823 lctx.cached_id.set(id_cache[&expr_id]);
825 // We're already tracking - check that the tracked id is the same
826 // as the expected id.
827 assert!(cached_id == id_cache[&expr_id], "id mismatch");
830 id_cache.insert(expr_id, lctx.id_assigner.peek_node_id());
834 // Only reset the id if it was previously 0, i.e., was not cached.
835 // If it was cached, we are in a nested node, but our id count will
836 // still count towards the parent's count.
837 reset: lctx.cached_id.get() == 0,
843 impl<'a> Drop for CachedIdSetter<'a> {
846 self.lctx.cached_id.set(0);
851 pub fn lower_expr(lctx: &LoweringContext, e: &Expr) -> P<hir::Expr> {
856 // Eventually a desugaring for `box EXPR`
857 // (similar to the desugaring above for `in PLACE BLOCK`)
858 // should go here, desugaring
862 // let mut place = BoxPlace::make_place();
863 // let raw_place = Place::pointer(&mut place);
864 // let value = $value;
866 // ::std::ptr::write(raw_place, value);
867 // Boxed::finalize(place)
870 // But for now there are type-inference issues doing that.
872 hir::ExprBox(lower_expr(lctx, e))
875 // Desugar ExprBox: `in (PLACE) EXPR`
876 ExprInPlace(ref placer, ref value_expr) => {
880 // let mut place = Placer::make_place(p);
881 // let raw_place = Place::pointer(&mut place);
883 // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR ));
884 // InPlace::finalize(place)
886 let _old_cached = CachedIdSetter::new(lctx, e.id);
888 let placer_expr = lower_expr(lctx, placer);
889 let value_expr = lower_expr(lctx, value_expr);
891 let placer_ident = token::gensym_ident("placer");
892 let agent_ident = token::gensym_ident("place");
893 let p_ptr_ident = token::gensym_ident("p_ptr");
895 let make_place = ["ops", "Placer", "make_place"];
896 let place_pointer = ["ops", "Place", "pointer"];
897 let move_val_init = ["intrinsics", "move_val_init"];
898 let inplace_finalize = ["ops", "InPlace", "finalize"];
900 let make_call = |lctx, p, args| {
901 let path = core_path(lctx, e.span, p);
902 let path = expr_path(lctx, path);
903 expr_call(lctx, e.span, path, args)
906 let mk_stmt_let = |lctx, bind, expr| {
907 stmt_let(lctx, e.span, false, bind, expr)
909 let mk_stmt_let_mut = |lctx, bind, expr| {
910 stmt_let(lctx, e.span, true, bind, expr)
913 // let placer = <placer_expr> ;
914 let s1 = mk_stmt_let(lctx, placer_ident, placer_expr);
916 // let mut place = Placer::make_place(placer);
918 let call = make_call(lctx, &make_place, vec![expr_ident(lctx, e.span, placer_ident)]);
919 mk_stmt_let_mut(lctx, agent_ident, call)
922 // let p_ptr = Place::pointer(&mut place);
924 let args = vec![expr_mut_addr_of(lctx, e.span, expr_ident(lctx, e.span, agent_ident))];
925 let call = make_call(lctx, &place_pointer, args);
926 mk_stmt_let(lctx, p_ptr_ident, call)
929 // pop_unsafe!(EXPR));
930 let pop_unsafe_expr =
931 signal_block_expr(lctx,
933 signal_block_expr(lctx,
937 hir::PopUnstableBlock),
939 hir::PopUnsafeBlock(hir::CompilerGenerated));
942 // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR ));
943 // InPlace::finalize(place)
946 let call_move_val_init =
947 hir::StmtSemi(make_call(lctx,
949 vec![expr_ident(lctx, e.span, p_ptr_ident),
952 let call_move_val_init = respan(e.span, call_move_val_init);
954 let call = make_call(lctx, &inplace_finalize, vec![expr_ident(lctx, e.span, agent_ident)]);
955 signal_block_expr(lctx,
956 vec![P(call_move_val_init)],
959 hir::PushUnsafeBlock(hir::CompilerGenerated))
962 return signal_block_expr(lctx,
966 hir::PushUnstableBlock);
969 ExprVec(ref exprs) => {
970 hir::ExprVec(exprs.iter().map(|x| lower_expr(lctx, x)).collect())
972 ExprRepeat(ref expr, ref count) => {
973 hir::ExprRepeat(lower_expr(lctx, expr), lower_expr(lctx, count))
975 ExprTup(ref elts) => {
976 hir::ExprTup(elts.iter().map(|x| lower_expr(lctx, x)).collect())
978 ExprCall(ref f, ref args) => {
979 hir::ExprCall(lower_expr(lctx, f),
980 args.iter().map(|x| lower_expr(lctx, x)).collect())
982 ExprMethodCall(i, ref tps, ref args) => {
984 respan(i.span, i.node.name),
985 tps.iter().map(|x| lower_ty(lctx, x)).collect(),
986 args.iter().map(|x| lower_expr(lctx, x)).collect())
988 ExprBinary(binop, ref lhs, ref rhs) => {
989 hir::ExprBinary(lower_binop(lctx, binop),
990 lower_expr(lctx, lhs),
991 lower_expr(lctx, rhs))
993 ExprUnary(op, ref ohs) => {
994 hir::ExprUnary(lower_unop(lctx, op), lower_expr(lctx, ohs))
996 ExprLit(ref l) => hir::ExprLit(P((**l).clone())),
997 ExprCast(ref expr, ref ty) => {
998 hir::ExprCast(lower_expr(lctx, expr), lower_ty(lctx, ty))
1000 ExprAddrOf(m, ref ohs) => {
1001 hir::ExprAddrOf(lower_mutability(lctx, m), lower_expr(lctx, ohs))
1003 // More complicated than you might expect because the else branch
1004 // might be `if let`.
1005 ExprIf(ref cond, ref blk, ref else_opt) => {
1006 let else_opt = else_opt.as_ref().map(|els| match els.node {
1008 let _old_cached = CachedIdSetter::new(lctx, e.id);
1009 // wrap the if-let expr in a block
1010 let span = els.span;
1011 let blk = P(hir::Block {
1013 expr: Some(lower_expr(lctx, els)),
1015 rules: hir::DefaultBlock,
1018 expr_block(lctx, blk)
1020 _ => lower_expr(lctx, els)
1023 hir::ExprIf(lower_expr(lctx, cond),
1024 lower_block(lctx, blk),
1027 ExprWhile(ref cond, ref body, opt_ident) => {
1028 hir::ExprWhile(lower_expr(lctx, cond),
1029 lower_block(lctx, body),
1032 ExprLoop(ref body, opt_ident) => {
1033 hir::ExprLoop(lower_block(lctx, body),
1036 ExprMatch(ref expr, ref arms) => {
1037 hir::ExprMatch(lower_expr(lctx, expr),
1038 arms.iter().map(|x| lower_arm(lctx, x)).collect(),
1039 hir::MatchSource::Normal)
1041 ExprClosure(capture_clause, ref decl, ref body) => {
1042 hir::ExprClosure(lower_capture_clause(lctx, capture_clause),
1043 lower_fn_decl(lctx, decl),
1044 lower_block(lctx, body))
1046 ExprBlock(ref blk) => hir::ExprBlock(lower_block(lctx, blk)),
1047 ExprAssign(ref el, ref er) => {
1048 hir::ExprAssign(lower_expr(lctx, el), lower_expr(lctx, er))
1050 ExprAssignOp(op, ref el, ref er) => {
1051 hir::ExprAssignOp(lower_binop(lctx, op),
1052 lower_expr(lctx, el),
1053 lower_expr(lctx, er))
1055 ExprField(ref el, ident) => {
1056 hir::ExprField(lower_expr(lctx, el), respan(ident.span, ident.node.name))
1058 ExprTupField(ref el, ident) => {
1059 hir::ExprTupField(lower_expr(lctx, el), ident)
1061 ExprIndex(ref el, ref er) => {
1062 hir::ExprIndex(lower_expr(lctx, el), lower_expr(lctx, er))
1064 ExprRange(ref e1, ref e2) => {
1065 hir::ExprRange(e1.as_ref().map(|x| lower_expr(lctx, x)),
1066 e2.as_ref().map(|x| lower_expr(lctx, x)))
1068 ExprPath(ref qself, ref path) => {
1069 let qself = qself.as_ref().map(|&QSelf { ref ty, position }| {
1071 ty: lower_ty(lctx, ty),
1075 hir::ExprPath(qself, lower_path(lctx, path))
1077 ExprBreak(opt_ident) => hir::ExprBreak(opt_ident),
1078 ExprAgain(opt_ident) => hir::ExprAgain(opt_ident),
1079 ExprRet(ref e) => hir::ExprRet(e.as_ref().map(|x| lower_expr(lctx, x))),
1080 ExprInlineAsm(InlineAsm {
1090 }) => hir::ExprInlineAsm(hir::InlineAsm {
1091 inputs: inputs.iter().map(|&(ref c, ref input)| {
1092 (c.clone(), lower_expr(lctx, input))
1094 outputs: outputs.iter().map(|&(ref c, ref out, ref is_rw)| {
1095 (c.clone(), lower_expr(lctx, out), *is_rw)
1098 asm_str_style: asm_str_style,
1099 clobbers: clobbers.clone(),
1101 alignstack: alignstack,
1105 ExprStruct(ref path, ref fields, ref maybe_expr) => {
1106 hir::ExprStruct(lower_path(lctx, path),
1107 fields.iter().map(|x| lower_field(lctx, x)).collect(),
1108 maybe_expr.as_ref().map(|x| lower_expr(lctx, x)))
1110 ExprParen(ref ex) => {
1111 return lower_expr(lctx, ex);
1114 // Desugar ExprIfLet
1115 // From: `if let <pat> = <sub_expr> <body> [<else_opt>]`
1116 ExprIfLet(ref pat, ref sub_expr, ref body, ref else_opt) => {
1119 // match <sub_expr> {
1121 // [_ if <else_opt_if_cond> => <else_opt_if_body>,]
1122 // _ => [<else_opt> | ()]
1125 let _old_cached = CachedIdSetter::new(lctx, e.id);
1127 // `<pat> => <body>`
1129 let body_expr = expr_block(lctx, lower_block(lctx, body));
1130 arm(vec![lower_pat(lctx, pat)], body_expr)
1133 // `[_ if <else_opt_if_cond> => <else_opt_if_body>,]`
1134 let mut else_opt = else_opt.as_ref().map(|e| lower_expr(lctx, e));
1135 let else_if_arms = {
1136 let mut arms = vec![];
1138 let else_opt_continue = else_opt
1139 .and_then(|els| els.and_then(|els| match els.node {
1141 hir::ExprIf(cond, then, else_opt) => {
1142 let pat_under = pat_wild(lctx, e.span);
1143 arms.push(hir::Arm {
1145 pats: vec![pat_under],
1147 body: expr_block(lctx, then)
1149 else_opt.map(|else_opt| (else_opt, true))
1151 _ => Some((P(els), false))
1153 match else_opt_continue {
1154 Some((e, true)) => {
1157 Some((e, false)) => {
1170 let contains_else_clause = else_opt.is_some();
1172 // `_ => [<else_opt> | ()]`
1174 let pat_under = pat_wild(lctx, e.span);
1175 let else_expr = else_opt.unwrap_or_else(|| expr_tuple(lctx, e.span, vec![]));
1176 arm(vec![pat_under], else_expr)
1179 let mut arms = Vec::with_capacity(else_if_arms.len() + 2);
1181 arms.extend(else_if_arms);
1182 arms.push(else_arm);
1184 let match_expr = expr(lctx,
1186 hir::ExprMatch(lower_expr(lctx, sub_expr), arms,
1187 hir::MatchSource::IfLetDesugar {
1188 contains_else_clause: contains_else_clause,
1193 // Desugar ExprWhileLet
1194 // From: `[opt_ident]: while let <pat> = <sub_expr> <body>`
1195 ExprWhileLet(ref pat, ref sub_expr, ref body, opt_ident) => {
1198 // [opt_ident]: loop {
1199 // match <sub_expr> {
1205 let _old_cached = CachedIdSetter::new(lctx, e.id);
1207 // `<pat> => <body>`
1209 let body_expr = expr_block(lctx, lower_block(lctx, body));
1210 arm(vec![lower_pat(lctx, pat)], body_expr)
1215 let pat_under = pat_wild(lctx, e.span);
1216 let break_expr = expr_break(lctx, e.span);
1217 arm(vec![pat_under], break_expr)
1220 // // `match <sub_expr> { ... }`
1221 let arms = vec![pat_arm, break_arm];
1222 let match_expr = expr(lctx,
1224 hir::ExprMatch(lower_expr(lctx, sub_expr), arms, hir::MatchSource::WhileLetDesugar));
1226 // `[opt_ident]: loop { ... }`
1227 let loop_block = block_expr(lctx, match_expr);
1228 return expr(lctx, e.span, hir::ExprLoop(loop_block, opt_ident));
1231 // Desugar ExprForLoop
1232 // From: `[opt_ident]: for <pat> in <head> <body>`
1233 ExprForLoop(ref pat, ref head, ref body, opt_ident) => {
1237 // let result = match ::std::iter::IntoIterator::into_iter(<head>) {
1239 // [opt_ident]: loop {
1240 // match ::std::iter::Iterator::next(&mut iter) {
1241 // ::std::option::Option::Some(<pat>) => <body>,
1242 // ::std::option::Option::None => break
1250 let _old_cached = CachedIdSetter::new(lctx, e.id);
1253 let head = lower_expr(lctx, head);
1255 let iter = token::gensym_ident("iter");
1257 // `::std::option::Option::Some(<pat>) => <body>`
1259 let body_block = lower_block(lctx, body);
1260 let body_span = body_block.span;
1261 let body_expr = P(hir::Expr {
1263 node: hir::ExprBlock(body_block),
1266 let pat = lower_pat(lctx, pat);
1267 let some_pat = pat_some(lctx, e.span, pat);
1269 arm(vec![some_pat], body_expr)
1272 // `::std::option::Option::None => break`
1274 let break_expr = expr_break(lctx, e.span);
1276 arm(vec![pat_none(lctx, e.span)], break_expr)
1279 // `match ::std::iter::Iterator::next(&mut iter) { ... }`
1282 let strs = std_path(lctx, &["iter", "Iterator", "next"]);
1284 path_global(e.span, strs)
1286 let ref_mut_iter = expr_mut_addr_of(lctx, e.span, expr_ident(lctx, e.span, iter));
1288 expr_call(lctx, e.span, expr_path(lctx, next_path), vec![ref_mut_iter]);
1289 let arms = vec![pat_arm, break_arm];
1293 hir::ExprMatch(next_expr, arms, hir::MatchSource::ForLoopDesugar))
1296 // `[opt_ident]: loop { ... }`
1297 let loop_block = block_expr(lctx, match_expr);
1298 let loop_expr = expr(lctx, e.span, hir::ExprLoop(loop_block, opt_ident));
1300 // `mut iter => { ... }`
1303 pat_ident_binding_mode(lctx, e.span, iter, hir::BindByValue(hir::MutMutable));
1304 arm(vec![iter_pat], loop_expr)
1307 // `match ::std::iter::IntoIterator::into_iter(<head>) { ... }`
1308 let into_iter_expr = {
1309 let into_iter_path = {
1310 let strs = std_path(lctx, &["iter", "IntoIterator", "into_iter"]);
1312 path_global(e.span, strs)
1315 expr_call(lctx, e.span, expr_path(lctx, into_iter_path), vec![head])
1318 let match_expr = expr_match(lctx, e.span, into_iter_expr, vec![iter_arm]);
1320 // `{ let result = ...; result }`
1321 let result_ident = token::gensym_ident("result");
1322 return expr_block(lctx,
1325 vec![stmt_let(lctx, e.span,
1329 Some(expr_ident(lctx, e.span, result_ident))))
1332 ExprMac(_) => panic!("Shouldn't exist here"),
1338 pub fn lower_stmt(_lctx: &LoweringContext, s: &Stmt) -> P<hir::Stmt> {
1340 StmtDecl(ref d, id) => {
1342 node: hir::StmtDecl(lower_decl(_lctx, d), id),
1346 StmtExpr(ref e, id) => {
1348 node: hir::StmtExpr(lower_expr(_lctx, e), id),
1352 StmtSemi(ref e, id) => {
1354 node: hir::StmtSemi(lower_expr(_lctx, e), id),
1358 StmtMac(..) => panic!("Shouldn't exist here"),
1362 pub fn lower_capture_clause(_lctx: &LoweringContext, c: CaptureClause) -> hir::CaptureClause {
1364 CaptureByValue => hir::CaptureByValue,
1365 CaptureByRef => hir::CaptureByRef,
1369 pub fn lower_visibility(_lctx: &LoweringContext, v: Visibility) -> hir::Visibility {
1371 Public => hir::Public,
1372 Inherited => hir::Inherited,
1376 pub fn lower_block_check_mode(_lctx: &LoweringContext, b: &BlockCheckMode) -> hir::BlockCheckMode {
1378 DefaultBlock => hir::DefaultBlock,
1379 UnsafeBlock(u) => hir::UnsafeBlock(lower_unsafe_source(_lctx, u)),
1380 PushUnsafeBlock(u) => hir::PushUnsafeBlock(lower_unsafe_source(_lctx, u)),
1381 PopUnsafeBlock(u) => hir::PopUnsafeBlock(lower_unsafe_source(_lctx, u)),
1385 pub fn lower_pat_wild_kind(_lctx: &LoweringContext, p: PatWildKind) -> hir::PatWildKind {
1387 PatWildSingle => hir::PatWildSingle,
1388 PatWildMulti => hir::PatWildMulti,
1392 pub fn lower_binding_mode(_lctx: &LoweringContext, b: &BindingMode) -> hir::BindingMode {
1394 BindByRef(m) => hir::BindByRef(lower_mutability(_lctx, m)),
1395 BindByValue(m) => hir::BindByValue(lower_mutability(_lctx, m)),
1399 pub fn lower_struct_field_kind(_lctx: &LoweringContext,
1400 s: &StructFieldKind)
1401 -> hir::StructFieldKind {
1403 NamedField(ident, vis) => hir::NamedField(ident.name, lower_visibility(_lctx, vis)),
1404 UnnamedField(vis) => hir::UnnamedField(lower_visibility(_lctx, vis)),
1408 pub fn lower_unsafe_source(_lctx: &LoweringContext, u: UnsafeSource) -> hir::UnsafeSource {
1410 CompilerGenerated => hir::CompilerGenerated,
1411 UserProvided => hir::UserProvided,
1415 pub fn lower_impl_polarity(_lctx: &LoweringContext, i: ImplPolarity) -> hir::ImplPolarity {
1417 ImplPolarity::Positive => hir::ImplPolarity::Positive,
1418 ImplPolarity::Negative => hir::ImplPolarity::Negative,
1422 pub fn lower_trait_bound_modifier(_lctx: &LoweringContext,
1423 f: TraitBoundModifier)
1424 -> hir::TraitBoundModifier {
1426 TraitBoundModifier::None => hir::TraitBoundModifier::None,
1427 TraitBoundModifier::Maybe => hir::TraitBoundModifier::Maybe,
1431 // Helper methods for building HIR.
1433 fn arm(pats: Vec<P<hir::Pat>>, expr: P<hir::Expr>) -> hir::Arm {
1442 fn expr_break(lctx: &LoweringContext, span: Span) -> P<hir::Expr> {
1443 expr(lctx, span, hir::ExprBreak(None))
1446 fn expr_call(lctx: &LoweringContext, span: Span, e: P<hir::Expr>, args: Vec<P<hir::Expr>>) -> P<hir::Expr> {
1447 expr(lctx, span, hir::ExprCall(e, args))
1450 fn expr_ident(lctx: &LoweringContext, span: Span, id: Ident) -> P<hir::Expr> {
1451 expr_path(lctx, path_ident(span, id))
1454 fn expr_mut_addr_of(lctx: &LoweringContext, span: Span, e: P<hir::Expr>) -> P<hir::Expr> {
1455 expr(lctx, span, hir::ExprAddrOf(hir::MutMutable, e))
1458 fn expr_path(lctx: &LoweringContext, path: hir::Path) -> P<hir::Expr> {
1459 expr(lctx, path.span, hir::ExprPath(None, path))
1462 fn expr_match(lctx: &LoweringContext, span: Span, arg: P<hir::Expr>, arms: Vec<hir::Arm>) -> P<hir::Expr> {
1463 expr(lctx, span, hir::ExprMatch(arg, arms, hir::MatchSource::Normal))
1466 fn expr_block(lctx: &LoweringContext, b: P<hir::Block>) -> P<hir::Expr> {
1467 expr(lctx, b.span, hir::ExprBlock(b))
1470 fn expr_tuple(lctx: &LoweringContext, sp: Span, exprs: Vec<P<hir::Expr>>) -> P<hir::Expr> {
1471 expr(lctx, sp, hir::ExprTup(exprs))
1474 fn expr(lctx: &LoweringContext, span: Span, node: hir::Expr_) -> P<hir::Expr> {
1482 fn stmt_let(lctx: &LoweringContext, sp: Span, mutbl: bool, ident: Ident, ex: P<hir::Expr>) -> P<hir::Stmt> {
1483 let pat = if mutbl {
1484 pat_ident_binding_mode(lctx, sp, ident, hir::BindByValue(hir::MutMutable))
1486 pat_ident(lctx, sp, ident)
1488 let local = P(hir::Local {
1495 let decl = respan(sp, hir::DeclLocal(local));
1496 P(respan(sp, hir::StmtDecl(P(decl), lctx.next_id())))
1499 fn block_expr(lctx: &LoweringContext, expr: P<hir::Expr>) -> P<hir::Block> {
1500 block_all(lctx, expr.span, Vec::new(), Some(expr))
1503 fn block_all(lctx: &LoweringContext,
1505 stmts: Vec<P<hir::Stmt>>,
1506 expr: Option<P<hir::Expr>>) -> P<hir::Block> {
1511 rules: hir::DefaultBlock,
1516 fn pat_some(lctx: &LoweringContext, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
1517 let some = std_path(lctx, &["option", "Option", "Some"]);
1518 let path = path_global(span, some);
1519 pat_enum(lctx, span, path, vec!(pat))
1522 fn pat_none(lctx: &LoweringContext, span: Span) -> P<hir::Pat> {
1523 let none = std_path(lctx, &["option", "Option", "None"]);
1524 let path = path_global(span, none);
1525 pat_enum(lctx, span, path, vec![])
1528 fn pat_enum(lctx: &LoweringContext, span: Span, path: hir::Path, subpats: Vec<P<hir::Pat>>) -> P<hir::Pat> {
1529 let pt = hir::PatEnum(path, Some(subpats));
1533 fn pat_ident(lctx: &LoweringContext, span: Span, ident: Ident) -> P<hir::Pat> {
1534 pat_ident_binding_mode(lctx, span, ident, hir::BindByValue(hir::MutImmutable))
1537 fn pat_ident_binding_mode(lctx: &LoweringContext,
1540 bm: hir::BindingMode) -> P<hir::Pat> {
1541 let pat_ident = hir::PatIdent(bm, Spanned{span: span, node: ident}, None);
1542 pat(lctx, span, pat_ident)
1545 fn pat_wild(lctx: &LoweringContext, span: Span) -> P<hir::Pat> {
1546 pat(lctx, span, hir::PatWild(hir::PatWildSingle))
1549 fn pat(lctx: &LoweringContext, span: Span, pat: hir::Pat_) -> P<hir::Pat> {
1550 P(hir::Pat { id: lctx.next_id(), node: pat, span: span })
1553 fn path_ident(span: Span, id: Ident) -> hir::Path {
1554 path(span, vec!(id))
1557 fn path(span: Span, strs: Vec<Ident> ) -> hir::Path {
1558 path_all(span, false, strs, Vec::new(), Vec::new(), Vec::new())
1561 fn path_global(span: Span, strs: Vec<Ident> ) -> hir::Path {
1562 path_all(span, true, strs, Vec::new(), Vec::new(), Vec::new())
1565 fn path_all(sp: Span,
1567 mut idents: Vec<Ident> ,
1568 lifetimes: Vec<hir::Lifetime>,
1569 types: Vec<P<hir::Ty>>,
1570 bindings: Vec<P<hir::TypeBinding>> )
1572 let last_identifier = idents.pop().unwrap();
1573 let mut segments: Vec<hir::PathSegment> = idents.into_iter()
1577 parameters: hir::PathParameters::none(),
1580 segments.push(hir::PathSegment {
1581 identifier: last_identifier,
1582 parameters: hir::AngleBracketedParameters(hir::AngleBracketedParameterData {
1583 lifetimes: lifetimes,
1584 types: OwnedSlice::from_vec(types),
1585 bindings: OwnedSlice::from_vec(bindings),
1595 fn std_path(lctx: &LoweringContext, components: &[&str]) -> Vec<Ident> {
1596 let mut v = Vec::new();
1597 if let Some(s) = lctx.crate_root {
1598 v.push(str_to_ident(s));
1600 v.extend(components.iter().map(|s| str_to_ident(s)));
1604 // Given suffix ["b","c","d"], returns path `::std::b::c::d` when
1605 // `fld.cx.use_std`, and `::core::b::c::d` otherwise.
1606 fn core_path(lctx: &LoweringContext, span: Span, components: &[&str]) -> hir::Path {
1607 let idents = std_path(lctx, components);
1608 path_global(span, idents)
1611 fn signal_block_expr(lctx: &LoweringContext, stmts: Vec<P<hir::Stmt>>, expr: P<hir::Expr>, span: Span, rule: hir::BlockCheckMode) -> P<hir::Expr> {
1612 expr_block(lctx, P(hir::Block {
1613 rules: rule, span: span, id: lctx.next_id(),
1614 stmts: stmts, expr: Some(expr),