X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=src%2Flibrustc_front%2Flowering.rs;h=bd5f7cf3c626eba2c81dba90444a1e7f9f1198fb;hb=ea47c2b6b349d7f252a6a734ced8204e6ef70546;hp=4b11e8b91e898cb27b9b61c9fdff724462987fbd;hpb=19fe7b6d6444424403be07699a8a312562ede51f;p=rust.git diff --git a/src/librustc_front/lowering.rs b/src/librustc_front/lowering.rs index 4b11e8b91e8..bd5f7cf3c62 100644 --- a/src/librustc_front/lowering.rs +++ b/src/librustc_front/lowering.rs @@ -8,118 +8,245 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -// Lowers the AST to the HIR +// Lowers the AST to the HIR. +// +// Since the AST and HIR are fairly similar, this is mostly a simple procedure, +// much like a fold. Where lowering involves a bit more work things get more +// interesting and there are some invariants you should know about. These mostly +// concern spans and ids. +// +// Spans are assigned to AST nodes during parsing and then are modified during +// expansion to indicate the origin of a node and the process it went through +// being expanded. Ids are assigned to AST nodes just before lowering. +// +// For the simpler lowering steps, ids and spans should be preserved. Unlike +// expansion we do not preserve the process of lowering in the spans, so spans +// should not be modified here. When creating a new node (as opposed to +// 'folding' an existing one), then you create a new id using `next_id()`. +// +// You must ensure that ids are unique. That means that you should only use the +// id from an AST node in a single HIR node (you can assume that AST node ids +// are unique). Every new node must have a unique id. Avoid cloning HIR nodes. +// If you do, you must then set the new node's id to a fresh one. +// +// Lowering must be reproducable (the compiler only lowers once, but tools and +// custom lints may lower an AST node to a HIR node to interact with the +// compiler). The most interesting bit of this is ids - if you lower an AST node +// and create new HIR nodes with fresh ids, when re-lowering the same node, you +// must ensure you get the same ids! To do this, we keep track of the next id +// when we translate a node which requires new ids. By checking this cache and +// using node ids starting with the cached id, we ensure ids are reproducible. +// To use this system, you just need to hold on to a CachedIdSetter object +// whilst lowering. This is an RAII object that takes care of setting and +// restoring the cached id, etc. +// +// This whole system relies on node ids being incremented one at a time and +// all increments being for lowering. This means that you should not call any +// non-lowering function which will use new node ids. +// +// We must also cache gensym'ed Idents to ensure that we get the same Ident +// every time we lower a node with gensym'ed names. One consequence of this is +// that you can only gensym a name once in a lowering (you don't need to worry +// about nested lowering though). That's because we cache based on the name and +// the currently cached node id, which is unique per lowered node. +// +// Spans are used for error messages and for tools to map semantics back to +// source code. It is therefore not as important with spans as ids to be strict +// about use (you can't break the compiler by screwing up a span). Obviously, a +// HIR node can only have a single span. But multiple nodes can have the same +// span and spans don't need to be kept in order, etc. Where code is preserved +// by lowering, it should have the same span as in the AST. Where HIR nodes are +// new it is probably best to give a span for the whole AST node being lowered. +// All nodes should have real spans, don't use dummy spans. Tools are likely to +// get confused if the spans from leaf AST nodes occur in multiple places +// in the HIR, especially for multiple identifiers. use hir; +use std::collections::HashMap; + use syntax::ast::*; use syntax::ptr::P; -use syntax::codemap::{respan, Spanned}; +use syntax::codemap::{respan, Spanned, Span}; use syntax::owned_slice::OwnedSlice; +use syntax::parse::token::{self, str_to_ident}; +use syntax::std_inject; + +use std::cell::{Cell, RefCell}; + +pub struct LoweringContext<'a> { + crate_root: Option<&'static str>, + // Map AST ids to ids used for expanded nodes. + id_cache: RefCell>, + // Use if there are no cached ids for the current node. + id_assigner: &'a NodeIdAssigner, + // 0 == no cached id. Must be incremented to align with previous id + // incrementing. + cached_id: Cell, + // Keep track of gensym'ed idents. + gensym_cache: RefCell>, + // A copy of cached_id, but is also set to an id while it is being cached. + gensym_key: Cell, +} + +impl<'a, 'hir> LoweringContext<'a> { + pub fn new(id_assigner: &'a NodeIdAssigner, c: Option<&Crate>) -> LoweringContext<'a> { + let crate_root = c.and_then(|c| { + if std_inject::no_core(c) { + None + } else if std_inject::no_std(c) { + Some("core") + } else { + Some("std") + } + }); + + LoweringContext { + crate_root: crate_root, + id_cache: RefCell::new(HashMap::new()), + id_assigner: id_assigner, + cached_id: Cell::new(0), + gensym_cache: RefCell::new(HashMap::new()), + gensym_key: Cell::new(0), + } + } + + fn next_id(&self) -> NodeId { + let cached = self.cached_id.get(); + if cached == 0 { + return self.id_assigner.next_node_id() + } + + self.cached_id.set(cached + 1); + cached + } + + fn str_to_ident(&self, s: &'static str) -> Ident { + let cached_id = self.gensym_key.get(); + if cached_id == 0 { + return token::gensym_ident(s); + } + let cached = self.gensym_cache.borrow().contains_key(&(cached_id, s)); + if cached { + self.gensym_cache.borrow()[&(cached_id, s)] + } else { + let result = token::gensym_ident(s); + self.gensym_cache.borrow_mut().insert((cached_id, s), result); + result + } + } +} -pub fn lower_view_path(view_path: &ViewPath) -> P { +pub fn lower_view_path(_lctx: &LoweringContext, view_path: &ViewPath) -> P { P(Spanned { node: match view_path.node { ViewPathSimple(ident, ref path) => { - hir::ViewPathSimple(ident.name, lower_path(path)) + hir::ViewPathSimple(ident.name, lower_path(_lctx, path)) } ViewPathGlob(ref path) => { - hir::ViewPathGlob(lower_path(path)) + hir::ViewPathGlob(lower_path(_lctx, path)) } ViewPathList(ref path, ref path_list_idents) => { - hir::ViewPathList(lower_path(path), - path_list_idents.iter().map(|path_list_ident| { - Spanned { - node: match path_list_ident.node { - PathListIdent { id, name, rename } => - hir::PathListIdent { - id: id, - name: name.name, - rename: rename.map(|x| x.name), - }, - PathListMod { id, rename } => - hir::PathListMod { - id: id, - rename: rename.map(|x| x.name) - } - }, - span: path_list_ident.span - } - }).collect()) + hir::ViewPathList(lower_path(_lctx, path), + path_list_idents.iter() + .map(|path_list_ident| { + Spanned { + node: match path_list_ident.node { + PathListIdent { id, name, rename } => + hir::PathListIdent { + id: id, + name: name.name, + rename: rename.map(|x| x.name), + }, + PathListMod { id, rename } => + hir::PathListMod { + id: id, + rename: rename.map(|x| x.name), + }, + }, + span: path_list_ident.span, + } + }) + .collect()) } }, span: view_path.span, }) } -pub fn lower_arm(arm: &Arm) -> hir::Arm { +pub fn lower_arm(_lctx: &LoweringContext, arm: &Arm) -> hir::Arm { hir::Arm { attrs: arm.attrs.clone(), - pats: arm.pats.iter().map(|x| lower_pat(x)).collect(), - guard: arm.guard.as_ref().map(|ref x| lower_expr(x)), - body: lower_expr(&arm.body), + pats: arm.pats.iter().map(|x| lower_pat(_lctx, x)).collect(), + guard: arm.guard.as_ref().map(|ref x| lower_expr(_lctx, x)), + body: lower_expr(_lctx, &arm.body), } } -pub fn lower_decl(d: &Decl) -> P { +pub fn lower_decl(_lctx: &LoweringContext, d: &Decl) -> P { match d.node { DeclLocal(ref l) => P(Spanned { - node: hir::DeclLocal(lower_local(l)), - span: d.span + node: hir::DeclLocal(lower_local(_lctx, l)), + span: d.span, }), DeclItem(ref it) => P(Spanned { - node: hir::DeclItem(lower_item(it)), - span: d.span + node: hir::DeclItem(lower_item(_lctx, it)), + span: d.span, }), } } -pub fn lower_ty_binding(b: &TypeBinding) -> P { - P(hir::TypeBinding { id: b.id, name: b.ident.name, ty: lower_ty(&b.ty), span: b.span }) +pub fn lower_ty_binding(_lctx: &LoweringContext, b: &TypeBinding) -> P { + P(hir::TypeBinding { + id: b.id, + name: b.ident.name, + ty: lower_ty(_lctx, &b.ty), + span: b.span, + }) } -pub fn lower_ty(t: &Ty) -> P { +pub fn lower_ty(_lctx: &LoweringContext, t: &Ty) -> P { P(hir::Ty { id: t.id, node: match t.node { TyInfer => hir::TyInfer, - TyVec(ref ty) => hir::TyVec(lower_ty(ty)), - TyPtr(ref mt) => hir::TyPtr(lower_mt(mt)), + TyVec(ref ty) => hir::TyVec(lower_ty(_lctx, ty)), + TyPtr(ref mt) => hir::TyPtr(lower_mt(_lctx, mt)), TyRptr(ref region, ref mt) => { - hir::TyRptr(lower_opt_lifetime(region), lower_mt(mt)) + hir::TyRptr(lower_opt_lifetime(_lctx, region), + lower_mt(_lctx, mt)) } TyBareFn(ref f) => { hir::TyBareFn(P(hir::BareFnTy { - lifetimes: lower_lifetime_defs(&f.lifetimes), - unsafety: lower_unsafety(f.unsafety), + lifetimes: lower_lifetime_defs(_lctx, &f.lifetimes), + unsafety: lower_unsafety(_lctx, f.unsafety), abi: f.abi, - decl: lower_fn_decl(&f.decl) + decl: lower_fn_decl(_lctx, &f.decl), })) } - TyTup(ref tys) => hir::TyTup(tys.iter().map(|ty| lower_ty(ty)).collect()), - TyParen(ref ty) => hir::TyParen(lower_ty(ty)), + TyTup(ref tys) => hir::TyTup(tys.iter().map(|ty| lower_ty(_lctx, ty)).collect()), + TyParen(ref ty) => hir::TyParen(lower_ty(_lctx, ty)), TyPath(ref qself, ref path) => { let qself = qself.as_ref().map(|&QSelf { ref ty, position }| { hir::QSelf { - ty: lower_ty(ty), - position: position + ty: lower_ty(_lctx, ty), + position: position, } }); - hir::TyPath(qself, lower_path(path)) + hir::TyPath(qself, lower_path(_lctx, path)) } TyObjectSum(ref ty, ref bounds) => { - hir::TyObjectSum(lower_ty(ty), - lower_bounds(bounds)) + hir::TyObjectSum(lower_ty(_lctx, ty), lower_bounds(_lctx, bounds)) } TyFixedLengthVec(ref ty, ref e) => { - hir::TyFixedLengthVec(lower_ty(ty), lower_expr(e)) + hir::TyFixedLengthVec(lower_ty(_lctx, ty), lower_expr(_lctx, e)) } TyTypeof(ref expr) => { - hir::TyTypeof(lower_expr(expr)) + hir::TyTypeof(lower_expr(_lctx, expr)) } TyPolyTraitRef(ref bounds) => { - hir::TyPolyTraitRef(bounds.iter().map(|b| lower_ty_param_bound(b)).collect()) + hir::TyPolyTraitRef(bounds.iter().map(|b| lower_ty_param_bound(_lctx, b)).collect()) } TyMac(_) => panic!("TyMac should have been expanded by now."), }, @@ -127,195 +254,234 @@ pub fn lower_ty(t: &Ty) -> P { }) } -pub fn lower_foreign_mod(fm: &ForeignMod) -> hir::ForeignMod { +pub fn lower_foreign_mod(_lctx: &LoweringContext, fm: &ForeignMod) -> hir::ForeignMod { hir::ForeignMod { abi: fm.abi, - items: fm.items.iter().map(|x| lower_foreign_item(x)).collect(), + items: fm.items.iter().map(|x| lower_foreign_item(_lctx, x)).collect(), } } -pub fn lower_variant(v: &Variant) -> P { +pub fn lower_variant(_lctx: &LoweringContext, v: &Variant) -> P { P(Spanned { node: hir::Variant_ { id: v.node.id, name: v.node.name.name, attrs: v.node.attrs.clone(), - kind: match v.node.kind { - TupleVariantKind(ref variant_args) => { - hir::TupleVariantKind(variant_args.iter().map(|ref x| - lower_variant_arg(x)).collect()) - } - StructVariantKind(ref struct_def) => { - hir::StructVariantKind(lower_struct_def(struct_def)) + kind: { + if v.node.def.ctor_id.is_none() { + hir::StructVariantKind(lower_struct_def(_lctx, &v.node.def)) + } else { + hir::TupleVariantKind(v.node.def.fields.iter().map(|ref field| { + hir::VariantArg { id: field.node.id, ty: lower_ty(_lctx, &field.node.ty) } + }).collect()) } }, - disr_expr: v.node.disr_expr.as_ref().map(|e| lower_expr(e)), + disr_expr: v.node.disr_expr.as_ref().map(|e| lower_expr(_lctx, e)), }, span: v.span, }) } -pub fn lower_path(p: &Path) -> hir::Path { +pub fn lower_path(_lctx: &LoweringContext, p: &Path) -> hir::Path { hir::Path { global: p.global, - segments: p.segments.iter().map(|&PathSegment {identifier, ref parameters}| - hir::PathSegment { - identifier: identifier, - parameters: lower_path_parameters(parameters), - }).collect(), + segments: p.segments + .iter() + .map(|&PathSegment { identifier, ref parameters }| { + hir::PathSegment { + identifier: identifier, + parameters: lower_path_parameters(_lctx, parameters), + } + }) + .collect(), span: p.span, } } -pub fn lower_path_parameters(path_parameters: &PathParameters) -> hir::PathParameters { +pub fn lower_path_parameters(_lctx: &LoweringContext, + path_parameters: &PathParameters) + -> hir::PathParameters { match *path_parameters { AngleBracketedParameters(ref data) => - hir::AngleBracketedParameters(lower_angle_bracketed_parameter_data(data)), + hir::AngleBracketedParameters(lower_angle_bracketed_parameter_data(_lctx, data)), ParenthesizedParameters(ref data) => - hir::ParenthesizedParameters(lower_parenthesized_parameter_data(data)), + hir::ParenthesizedParameters(lower_parenthesized_parameter_data(_lctx, data)), } } -pub fn lower_angle_bracketed_parameter_data(data: &AngleBracketedParameterData) +pub fn lower_angle_bracketed_parameter_data(_lctx: &LoweringContext, + data: &AngleBracketedParameterData) -> hir::AngleBracketedParameterData { let &AngleBracketedParameterData { ref lifetimes, ref types, ref bindings } = data; hir::AngleBracketedParameterData { - lifetimes: lower_lifetimes(lifetimes), - types: types.iter().map(|ty| lower_ty(ty)).collect(), - bindings: bindings.iter().map(|b| lower_ty_binding(b)).collect(), + lifetimes: lower_lifetimes(_lctx, lifetimes), + types: types.iter().map(|ty| lower_ty(_lctx, ty)).collect(), + bindings: bindings.iter().map(|b| lower_ty_binding(_lctx, b)).collect(), } } -pub fn lower_parenthesized_parameter_data(data: &ParenthesizedParameterData) +pub fn lower_parenthesized_parameter_data(_lctx: &LoweringContext, + data: &ParenthesizedParameterData) -> hir::ParenthesizedParameterData { let &ParenthesizedParameterData { ref inputs, ref output, span } = data; hir::ParenthesizedParameterData { - inputs: inputs.iter().map(|ty| lower_ty(ty)).collect(), - output: output.as_ref().map(|ty| lower_ty(ty)), + inputs: inputs.iter().map(|ty| lower_ty(_lctx, ty)).collect(), + output: output.as_ref().map(|ty| lower_ty(_lctx, ty)), span: span, } } -pub fn lower_local(l: &Local) -> P { +pub fn lower_local(_lctx: &LoweringContext, l: &Local) -> P { P(hir::Local { - id: l.id, - ty: l.ty.as_ref().map(|t| lower_ty(t)), - pat: lower_pat(&l.pat), - init: l.init.as_ref().map(|e| lower_expr(e)), - span: l.span, - }) + id: l.id, + ty: l.ty.as_ref().map(|t| lower_ty(_lctx, t)), + pat: lower_pat(_lctx, &l.pat), + init: l.init.as_ref().map(|e| lower_expr(_lctx, e)), + span: l.span, + }) } -pub fn lower_explicit_self_underscore(es: &ExplicitSelf_) -> hir::ExplicitSelf_ { +pub fn lower_explicit_self_underscore(_lctx: &LoweringContext, + es: &ExplicitSelf_) + -> hir::ExplicitSelf_ { match *es { SelfStatic => hir::SelfStatic, SelfValue(v) => hir::SelfValue(v.name), SelfRegion(ref lifetime, m, ident) => { - hir::SelfRegion(lower_opt_lifetime(lifetime), lower_mutability(m), ident.name) + hir::SelfRegion(lower_opt_lifetime(_lctx, lifetime), + lower_mutability(_lctx, m), + ident.name) } SelfExplicit(ref typ, ident) => { - hir::SelfExplicit(lower_ty(typ), ident.name) + hir::SelfExplicit(lower_ty(_lctx, typ), ident.name) } } } -pub fn lower_mutability(m: Mutability) -> hir::Mutability { +pub fn lower_mutability(_lctx: &LoweringContext, m: Mutability) -> hir::Mutability { match m { MutMutable => hir::MutMutable, MutImmutable => hir::MutImmutable, } } -pub fn lower_explicit_self(s: &ExplicitSelf) -> hir::ExplicitSelf { - Spanned { node: lower_explicit_self_underscore(&s.node), span: s.span } +pub fn lower_explicit_self(_lctx: &LoweringContext, s: &ExplicitSelf) -> hir::ExplicitSelf { + Spanned { + node: lower_explicit_self_underscore(_lctx, &s.node), + span: s.span, + } } -pub fn lower_arg(arg: &Arg) -> hir::Arg { - hir::Arg { id: arg.id, pat: lower_pat(&arg.pat), ty: lower_ty(&arg.ty) } +pub fn lower_arg(_lctx: &LoweringContext, arg: &Arg) -> hir::Arg { + hir::Arg { + id: arg.id, + pat: lower_pat(_lctx, &arg.pat), + ty: lower_ty(_lctx, &arg.ty), + } } -pub fn lower_fn_decl(decl: &FnDecl) -> P { +pub fn lower_fn_decl(_lctx: &LoweringContext, decl: &FnDecl) -> P { P(hir::FnDecl { - inputs: decl.inputs.iter().map(|x| lower_arg(x)).collect(), + inputs: decl.inputs.iter().map(|x| lower_arg(_lctx, x)).collect(), output: match decl.output { - Return(ref ty) => hir::Return(lower_ty(ty)), + Return(ref ty) => hir::Return(lower_ty(_lctx, ty)), DefaultReturn(span) => hir::DefaultReturn(span), - NoReturn(span) => hir::NoReturn(span) + NoReturn(span) => hir::NoReturn(span), }, variadic: decl.variadic, }) } -pub fn lower_ty_param_bound(tpb: &TyParamBound) -> hir::TyParamBound { +pub fn lower_ty_param_bound(_lctx: &LoweringContext, tpb: &TyParamBound) -> hir::TyParamBound { match *tpb { TraitTyParamBound(ref ty, modifier) => { - hir::TraitTyParamBound(lower_poly_trait_ref(ty), lower_trait_bound_modifier(modifier)) + hir::TraitTyParamBound(lower_poly_trait_ref(_lctx, ty), + lower_trait_bound_modifier(_lctx, modifier)) + } + RegionTyParamBound(ref lifetime) => { + hir::RegionTyParamBound(lower_lifetime(_lctx, lifetime)) } - RegionTyParamBound(ref lifetime) => hir::RegionTyParamBound(lower_lifetime(lifetime)), } } -pub fn lower_ty_param(tp: &TyParam) -> hir::TyParam { +pub fn lower_ty_param(_lctx: &LoweringContext, tp: &TyParam) -> hir::TyParam { hir::TyParam { id: tp.id, name: tp.ident.name, - bounds: lower_bounds(&tp.bounds), - default: tp.default.as_ref().map(|x| lower_ty(x)), + bounds: lower_bounds(_lctx, &tp.bounds), + default: tp.default.as_ref().map(|x| lower_ty(_lctx, x)), span: tp.span, } } -pub fn lower_ty_params(tps: &OwnedSlice) -> OwnedSlice { - tps.iter().map(|tp| lower_ty_param(tp)).collect() +pub fn lower_ty_params(_lctx: &LoweringContext, + tps: &OwnedSlice) + -> OwnedSlice { + tps.iter().map(|tp| lower_ty_param(_lctx, tp)).collect() } -pub fn lower_lifetime(l: &Lifetime) -> hir::Lifetime { - hir::Lifetime { id: l.id, name: l.name, span: l.span } +pub fn lower_lifetime(_lctx: &LoweringContext, l: &Lifetime) -> hir::Lifetime { + hir::Lifetime { + id: l.id, + name: l.name, + span: l.span, + } } -pub fn lower_lifetime_def(l: &LifetimeDef) -> hir::LifetimeDef { - hir::LifetimeDef { lifetime: lower_lifetime(&l.lifetime), bounds: lower_lifetimes(&l.bounds) } +pub fn lower_lifetime_def(_lctx: &LoweringContext, l: &LifetimeDef) -> hir::LifetimeDef { + hir::LifetimeDef { + lifetime: lower_lifetime(_lctx, &l.lifetime), + bounds: lower_lifetimes(_lctx, &l.bounds), + } } -pub fn lower_lifetimes(lts: &Vec) -> Vec { - lts.iter().map(|l| lower_lifetime(l)).collect() +pub fn lower_lifetimes(_lctx: &LoweringContext, lts: &Vec) -> Vec { + lts.iter().map(|l| lower_lifetime(_lctx, l)).collect() } -pub fn lower_lifetime_defs(lts: &Vec) -> Vec { - lts.iter().map(|l| lower_lifetime_def(l)).collect() +pub fn lower_lifetime_defs(_lctx: &LoweringContext, + lts: &Vec) + -> Vec { + lts.iter().map(|l| lower_lifetime_def(_lctx, l)).collect() } -pub fn lower_opt_lifetime(o_lt: &Option) -> Option { - o_lt.as_ref().map(|lt| lower_lifetime(lt)) +pub fn lower_opt_lifetime(_lctx: &LoweringContext, + o_lt: &Option) + -> Option { + o_lt.as_ref().map(|lt| lower_lifetime(_lctx, lt)) } -pub fn lower_generics(g: &Generics) -> hir::Generics { +pub fn lower_generics(_lctx: &LoweringContext, g: &Generics) -> hir::Generics { hir::Generics { - ty_params: lower_ty_params(&g.ty_params), - lifetimes: lower_lifetime_defs(&g.lifetimes), - where_clause: lower_where_clause(&g.where_clause), + ty_params: lower_ty_params(_lctx, &g.ty_params), + lifetimes: lower_lifetime_defs(_lctx, &g.lifetimes), + where_clause: lower_where_clause(_lctx, &g.where_clause), } } -pub fn lower_where_clause(wc: &WhereClause) -> hir::WhereClause { +pub fn lower_where_clause(_lctx: &LoweringContext, wc: &WhereClause) -> hir::WhereClause { hir::WhereClause { id: wc.id, - predicates: wc.predicates.iter().map(|predicate| - lower_where_predicate(predicate)).collect(), + predicates: wc.predicates + .iter() + .map(|predicate| lower_where_predicate(_lctx, predicate)) + .collect(), } } -pub fn lower_where_predicate(pred: &WherePredicate) -> hir::WherePredicate { +pub fn lower_where_predicate(_lctx: &LoweringContext, + pred: &WherePredicate) + -> hir::WherePredicate { match *pred { WherePredicate::BoundPredicate(WhereBoundPredicate{ ref bound_lifetimes, ref bounded_ty, ref bounds, span}) => { hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate { - bound_lifetimes: lower_lifetime_defs(bound_lifetimes), - bounded_ty: lower_ty(bounded_ty), - bounds: bounds.iter().map(|x| lower_ty_param_bound(x)).collect(), - span: span + bound_lifetimes: lower_lifetime_defs(_lctx, bound_lifetimes), + bounded_ty: lower_ty(_lctx, bounded_ty), + bounds: bounds.iter().map(|x| lower_ty_param_bound(_lctx, x)).collect(), + span: span, }) } WherePredicate::RegionPredicate(WhereRegionPredicate{ ref lifetime, @@ -323,145 +489,154 @@ pub fn lower_where_predicate(pred: &WherePredicate) -> hir::WherePredicate { span}) => { hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate { span: span, - lifetime: lower_lifetime(lifetime), - bounds: bounds.iter().map(|bound| lower_lifetime(bound)).collect() + lifetime: lower_lifetime(_lctx, lifetime), + bounds: bounds.iter().map(|bound| lower_lifetime(_lctx, bound)).collect(), }) } WherePredicate::EqPredicate(WhereEqPredicate{ id, ref path, ref ty, span}) => { - hir::WherePredicate::EqPredicate(hir::WhereEqPredicate{ + hir::WherePredicate::EqPredicate(hir::WhereEqPredicate { id: id, - path: lower_path(path), - ty:lower_ty(ty), - span: span + path: lower_path(_lctx, path), + ty: lower_ty(_lctx, ty), + span: span, }) } } } -pub fn lower_struct_def(sd: &StructDef) -> P { +pub fn lower_struct_def(_lctx: &LoweringContext, sd: &StructDef) -> P { P(hir::StructDef { - fields: sd.fields.iter().map(|f| lower_struct_field(f)).collect(), + fields: sd.fields.iter().map(|f| lower_struct_field(_lctx, f)).collect(), ctor_id: sd.ctor_id, }) } -pub fn lower_trait_ref(p: &TraitRef) -> hir::TraitRef { - hir::TraitRef { path: lower_path(&p.path), ref_id: p.ref_id } +pub fn lower_trait_ref(_lctx: &LoweringContext, p: &TraitRef) -> hir::TraitRef { + hir::TraitRef { + path: lower_path(_lctx, &p.path), + ref_id: p.ref_id, + } } -pub fn lower_poly_trait_ref(p: &PolyTraitRef) -> hir::PolyTraitRef { +pub fn lower_poly_trait_ref(_lctx: &LoweringContext, p: &PolyTraitRef) -> hir::PolyTraitRef { hir::PolyTraitRef { - bound_lifetimes: lower_lifetime_defs(&p.bound_lifetimes), - trait_ref: lower_trait_ref(&p.trait_ref), + bound_lifetimes: lower_lifetime_defs(_lctx, &p.bound_lifetimes), + trait_ref: lower_trait_ref(_lctx, &p.trait_ref), span: p.span, } } -pub fn lower_struct_field(f: &StructField) -> hir::StructField { +pub fn lower_struct_field(_lctx: &LoweringContext, f: &StructField) -> hir::StructField { Spanned { node: hir::StructField_ { id: f.node.id, - kind: lower_struct_field_kind(&f.node.kind), - ty: lower_ty(&f.node.ty), + kind: lower_struct_field_kind(_lctx, &f.node.kind), + ty: lower_ty(_lctx, &f.node.ty), attrs: f.node.attrs.clone(), }, span: f.span, } } -pub fn lower_field(f: &Field) -> hir::Field { +pub fn lower_field(_lctx: &LoweringContext, f: &Field) -> hir::Field { hir::Field { name: respan(f.ident.span, f.ident.node.name), - expr: lower_expr(&f.expr), span: f.span + expr: lower_expr(_lctx, &f.expr), + span: f.span, } } -pub fn lower_mt(mt: &MutTy) -> hir::MutTy { - hir::MutTy { ty: lower_ty(&mt.ty), mutbl: lower_mutability(mt.mutbl) } +pub fn lower_mt(_lctx: &LoweringContext, mt: &MutTy) -> hir::MutTy { + hir::MutTy { + ty: lower_ty(_lctx, &mt.ty), + mutbl: lower_mutability(_lctx, mt.mutbl), + } } -pub fn lower_opt_bounds(b: &Option>) +pub fn lower_opt_bounds(_lctx: &LoweringContext, + b: &Option>) -> Option> { - b.as_ref().map(|ref bounds| lower_bounds(bounds)) + b.as_ref().map(|ref bounds| lower_bounds(_lctx, bounds)) } -fn lower_bounds(bounds: &TyParamBounds) -> hir::TyParamBounds { - bounds.iter().map(|bound| lower_ty_param_bound(bound)).collect() +fn lower_bounds(_lctx: &LoweringContext, bounds: &TyParamBounds) -> hir::TyParamBounds { + bounds.iter().map(|bound| lower_ty_param_bound(_lctx, bound)).collect() } -fn lower_variant_arg(va: &VariantArg) -> hir::VariantArg { - hir::VariantArg { id: va.id, ty: lower_ty(&va.ty) } -} - -pub fn lower_block(b: &Block) -> P { +pub fn lower_block(_lctx: &LoweringContext, b: &Block) -> P { P(hir::Block { id: b.id, - stmts: b.stmts.iter().map(|s| lower_stmt(s)).collect(), - expr: b.expr.as_ref().map(|ref x| lower_expr(x)), - rules: lower_block_check_mode(&b.rules), + stmts: b.stmts.iter().map(|s| lower_stmt(_lctx, s)).collect(), + expr: b.expr.as_ref().map(|ref x| lower_expr(_lctx, x)), + rules: lower_block_check_mode(_lctx, &b.rules), span: b.span, }) } -pub fn lower_item_underscore(i: &Item_) -> hir::Item_ { +pub fn lower_item_underscore(_lctx: &LoweringContext, i: &Item_) -> hir::Item_ { match *i { ItemExternCrate(string) => hir::ItemExternCrate(string), ItemUse(ref view_path) => { - hir::ItemUse(lower_view_path(view_path)) + hir::ItemUse(lower_view_path(_lctx, view_path)) } ItemStatic(ref t, m, ref e) => { - hir::ItemStatic(lower_ty(t), lower_mutability(m), lower_expr(e)) + hir::ItemStatic(lower_ty(_lctx, t), + lower_mutability(_lctx, m), + lower_expr(_lctx, e)) } ItemConst(ref t, ref e) => { - hir::ItemConst(lower_ty(t), lower_expr(e)) + hir::ItemConst(lower_ty(_lctx, t), lower_expr(_lctx, e)) } ItemFn(ref decl, unsafety, constness, abi, ref generics, ref body) => { - hir::ItemFn( - lower_fn_decl(decl), - lower_unsafety(unsafety), - lower_constness(constness), - abi, - lower_generics(generics), - lower_block(body) - ) - } - ItemMod(ref m) => hir::ItemMod(lower_mod(m)), - ItemForeignMod(ref nm) => hir::ItemForeignMod(lower_foreign_mod(nm)), + hir::ItemFn(lower_fn_decl(_lctx, decl), + lower_unsafety(_lctx, unsafety), + lower_constness(_lctx, constness), + abi, + lower_generics(_lctx, generics), + lower_block(_lctx, body)) + } + ItemMod(ref m) => hir::ItemMod(lower_mod(_lctx, m)), + ItemForeignMod(ref nm) => hir::ItemForeignMod(lower_foreign_mod(_lctx, nm)), ItemTy(ref t, ref generics) => { - hir::ItemTy(lower_ty(t), lower_generics(generics)) + hir::ItemTy(lower_ty(_lctx, t), lower_generics(_lctx, generics)) } ItemEnum(ref enum_definition, ref generics) => { - hir::ItemEnum( - hir::EnumDef { - variants: enum_definition.variants.iter().map(|x| lower_variant(x)).collect(), - }, - lower_generics(generics)) + hir::ItemEnum(hir::EnumDef { + variants: enum_definition.variants + .iter() + .map(|x| lower_variant(_lctx, x)) + .collect(), + }, + lower_generics(_lctx, generics)) } ItemStruct(ref struct_def, ref generics) => { - let struct_def = lower_struct_def(struct_def); - hir::ItemStruct(struct_def, lower_generics(generics)) + let struct_def = lower_struct_def(_lctx, struct_def); + hir::ItemStruct(struct_def, lower_generics(_lctx, generics)) } ItemDefaultImpl(unsafety, ref trait_ref) => { - hir::ItemDefaultImpl(lower_unsafety(unsafety), lower_trait_ref(trait_ref)) + hir::ItemDefaultImpl(lower_unsafety(_lctx, unsafety), + lower_trait_ref(_lctx, trait_ref)) } ItemImpl(unsafety, polarity, ref generics, ref ifce, ref ty, ref impl_items) => { - let new_impl_items = impl_items.iter().map(|item| lower_impl_item(item)).collect(); - let ifce = ifce.as_ref().map(|trait_ref| lower_trait_ref(trait_ref)); - hir::ItemImpl(lower_unsafety(unsafety), - lower_impl_polarity(polarity), - lower_generics(generics), + let new_impl_items = impl_items.iter() + .map(|item| lower_impl_item(_lctx, item)) + .collect(); + let ifce = ifce.as_ref().map(|trait_ref| lower_trait_ref(_lctx, trait_ref)); + hir::ItemImpl(lower_unsafety(_lctx, unsafety), + lower_impl_polarity(_lctx, polarity), + lower_generics(_lctx, generics), ifce, - lower_ty(ty), + lower_ty(_lctx, ty), new_impl_items) } ItemTrait(unsafety, ref generics, ref bounds, ref items) => { - let bounds = lower_bounds(bounds); - let items = items.iter().map(|item| lower_trait_item(item)).collect(); - hir::ItemTrait(lower_unsafety(unsafety), - lower_generics(generics), + let bounds = lower_bounds(_lctx, bounds); + let items = items.iter().map(|item| lower_trait_item(_lctx, item)).collect(); + hir::ItemTrait(lower_unsafety(_lctx, unsafety), + lower_generics(_lctx, generics), bounds, items) } @@ -469,65 +644,68 @@ pub fn lower_item_underscore(i: &Item_) -> hir::Item_ { } } -pub fn lower_trait_item(i: &TraitItem) -> P { +pub fn lower_trait_item(_lctx: &LoweringContext, i: &TraitItem) -> P { P(hir::TraitItem { - id: i.id, - name: i.ident.name, - attrs: i.attrs.clone(), - node: match i.node { + id: i.id, + name: i.ident.name, + attrs: i.attrs.clone(), + node: match i.node { ConstTraitItem(ref ty, ref default) => { - hir::ConstTraitItem(lower_ty(ty), - default.as_ref().map(|x| lower_expr(x))) + hir::ConstTraitItem(lower_ty(_lctx, ty), + default.as_ref().map(|x| lower_expr(_lctx, x))) } MethodTraitItem(ref sig, ref body) => { - hir::MethodTraitItem(lower_method_sig(sig), - body.as_ref().map(|x| lower_block(x))) + hir::MethodTraitItem(lower_method_sig(_lctx, sig), + body.as_ref().map(|x| lower_block(_lctx, x))) } TypeTraitItem(ref bounds, ref default) => { - hir::TypeTraitItem(lower_bounds(bounds), - default.as_ref().map(|x| lower_ty(x))) + hir::TypeTraitItem(lower_bounds(_lctx, bounds), + default.as_ref().map(|x| lower_ty(_lctx, x))) } }, - span: i.span, - }) + span: i.span, + }) } -pub fn lower_impl_item(i: &ImplItem) -> P { +pub fn lower_impl_item(_lctx: &LoweringContext, i: &ImplItem) -> P { P(hir::ImplItem { - id: i.id, - name: i.ident.name, - attrs: i.attrs.clone(), - vis: lower_visibility(i.vis), - node: match i.node { + id: i.id, + name: i.ident.name, + attrs: i.attrs.clone(), + vis: lower_visibility(_lctx, i.vis), + node: match i.node { ConstImplItem(ref ty, ref expr) => { - hir::ConstImplItem(lower_ty(ty), lower_expr(expr)) + hir::ConstImplItem(lower_ty(_lctx, ty), lower_expr(_lctx, expr)) } MethodImplItem(ref sig, ref body) => { - hir::MethodImplItem(lower_method_sig(sig), - lower_block(body)) + hir::MethodImplItem(lower_method_sig(_lctx, sig), + lower_block(_lctx, body)) } - TypeImplItem(ref ty) => hir::TypeImplItem(lower_ty(ty)), + TypeImplItem(ref ty) => hir::TypeImplItem(lower_ty(_lctx, ty)), MacImplItem(..) => panic!("Shouldn't exist any more"), }, - span: i.span, - }) + span: i.span, + }) } -pub fn lower_mod(m: &Mod) -> hir::Mod { - hir::Mod { inner: m.inner, items: m.items.iter().map(|x| lower_item(x)).collect() } +pub fn lower_mod(_lctx: &LoweringContext, m: &Mod) -> hir::Mod { + hir::Mod { + inner: m.inner, + items: m.items.iter().map(|x| lower_item(_lctx, x)).collect(), + } } -pub fn lower_crate(c: &Crate) -> hir::Crate { +pub fn lower_crate(_lctx: &LoweringContext, c: &Crate) -> hir::Crate { hir::Crate { - module: lower_mod(&c.module), + module: lower_mod(_lctx, &c.module), attrs: c.attrs.clone(), config: c.config.clone(), span: c.span, - exported_macros: c.exported_macros.iter().map(|m| lower_macro_def(m)).collect(), + exported_macros: c.exported_macros.iter().map(|m| lower_macro_def(_lctx, m)).collect(), } } -pub fn lower_macro_def(m: &MacroDef) -> hir::MacroDef { +pub fn lower_macro_def(_lctx: &LoweringContext, m: &MacroDef) -> hir::MacroDef { hir::MacroDef { name: m.ident.name, attrs: m.attrs.clone(), @@ -542,68 +720,69 @@ pub fn lower_macro_def(m: &MacroDef) -> hir::MacroDef { } // fold one item into possibly many items -pub fn lower_item(i: &Item) -> P { - P(lower_item_simple(i)) +pub fn lower_item(_lctx: &LoweringContext, i: &Item) -> P { + P(lower_item_simple(_lctx, i)) } // fold one item into exactly one item -pub fn lower_item_simple(i: &Item) -> hir::Item { - let node = lower_item_underscore(&i.node); +pub fn lower_item_simple(_lctx: &LoweringContext, i: &Item) -> hir::Item { + let node = lower_item_underscore(_lctx, &i.node); hir::Item { id: i.id, name: i.ident.name, attrs: i.attrs.clone(), node: node, - vis: lower_visibility(i.vis), + vis: lower_visibility(_lctx, i.vis), span: i.span, } } -pub fn lower_foreign_item(i: &ForeignItem) -> P { +pub fn lower_foreign_item(_lctx: &LoweringContext, i: &ForeignItem) -> P { P(hir::ForeignItem { - id: i.id, - name: i.ident.name, - attrs: i.attrs.clone(), - node: match i.node { + id: i.id, + name: i.ident.name, + attrs: i.attrs.clone(), + node: match i.node { ForeignItemFn(ref fdec, ref generics) => { - hir::ForeignItemFn(lower_fn_decl(fdec), lower_generics(generics)) + hir::ForeignItemFn(lower_fn_decl(_lctx, fdec), + lower_generics(_lctx, generics)) } ForeignItemStatic(ref t, m) => { - hir::ForeignItemStatic(lower_ty(t), m) + hir::ForeignItemStatic(lower_ty(_lctx, t), m) } }, - vis: lower_visibility(i.vis), - span: i.span, - }) + vis: lower_visibility(_lctx, i.vis), + span: i.span, + }) } -pub fn lower_method_sig(sig: &MethodSig) -> hir::MethodSig { +pub fn lower_method_sig(_lctx: &LoweringContext, sig: &MethodSig) -> hir::MethodSig { hir::MethodSig { - generics: lower_generics(&sig.generics), + generics: lower_generics(_lctx, &sig.generics), abi: sig.abi, - explicit_self: lower_explicit_self(&sig.explicit_self), - unsafety: lower_unsafety(sig.unsafety), - constness: lower_constness(sig.constness), - decl: lower_fn_decl(&sig.decl), + explicit_self: lower_explicit_self(_lctx, &sig.explicit_self), + unsafety: lower_unsafety(_lctx, sig.unsafety), + constness: lower_constness(_lctx, sig.constness), + decl: lower_fn_decl(_lctx, &sig.decl), } } -pub fn lower_unsafety(u: Unsafety) -> hir::Unsafety { +pub fn lower_unsafety(_lctx: &LoweringContext, u: Unsafety) -> hir::Unsafety { match u { Unsafety::Unsafe => hir::Unsafety::Unsafe, Unsafety::Normal => hir::Unsafety::Normal, } } -pub fn lower_constness(c: Constness) -> hir::Constness { +pub fn lower_constness(_lctx: &LoweringContext, c: Constness) -> hir::Constness { match c { Constness::Const => hir::Constness::Const, Constness::NotConst => hir::Constness::NotConst, } } -pub fn lower_unop(u: UnOp) -> hir::UnOp { +pub fn lower_unop(_lctx: &LoweringContext, u: UnOp) -> hir::UnOp { match u { UnDeref => hir::UnDeref, UnNot => hir::UnNot, @@ -611,7 +790,7 @@ pub fn lower_unop(u: UnOp) -> hir::UnOp { } } -pub fn lower_binop(b: BinOp) -> hir::BinOp { +pub fn lower_binop(_lctx: &LoweringContext, b: BinOp) -> hir::BinOp { Spanned { node: match b.node { BiAdd => hir::BiAdd, @@ -637,154 +816,350 @@ pub fn lower_binop(b: BinOp) -> hir::BinOp { } } -pub fn lower_pat(p: &Pat) -> P { +pub fn lower_pat(_lctx: &LoweringContext, p: &Pat) -> P { P(hir::Pat { - id: p.id, - node: match p.node { - PatWild(k) => hir::PatWild(lower_pat_wild_kind(k)), + id: p.id, + node: match p.node { + PatWild(k) => hir::PatWild(lower_pat_wild_kind(_lctx, k)), PatIdent(ref binding_mode, pth1, ref sub) => { - hir::PatIdent(lower_binding_mode(binding_mode), - pth1, - sub.as_ref().map(|x| lower_pat(x))) + hir::PatIdent(lower_binding_mode(_lctx, binding_mode), + pth1, + sub.as_ref().map(|x| lower_pat(_lctx, x))) } - PatLit(ref e) => hir::PatLit(lower_expr(e)), + PatLit(ref e) => hir::PatLit(lower_expr(_lctx, e)), PatEnum(ref pth, ref pats) => { - hir::PatEnum(lower_path(pth), - pats.as_ref().map(|pats| pats.iter().map(|x| lower_pat(x)).collect())) + hir::PatEnum(lower_path(_lctx, pth), + pats.as_ref() + .map(|pats| pats.iter().map(|x| lower_pat(_lctx, x)).collect())) } PatQPath(ref qself, ref pth) => { let qself = hir::QSelf { - ty: lower_ty(&qself.ty), + ty: lower_ty(_lctx, &qself.ty), position: qself.position, }; - hir::PatQPath(qself, lower_path(pth)) + hir::PatQPath(qself, lower_path(_lctx, pth)) } PatStruct(ref pth, ref fields, etc) => { - let pth = lower_path(pth); - let fs = fields.iter().map(|f| { - Spanned { span: f.span, - node: hir::FieldPat { - name: f.node.ident.name, - pat: lower_pat(&f.node.pat), - is_shorthand: f.node.is_shorthand, - }} - }).collect(); + let pth = lower_path(_lctx, pth); + let fs = fields.iter() + .map(|f| { + Spanned { + span: f.span, + node: hir::FieldPat { + name: f.node.ident.name, + pat: lower_pat(_lctx, &f.node.pat), + is_shorthand: f.node.is_shorthand, + }, + } + }) + .collect(); hir::PatStruct(pth, fs, etc) } - PatTup(ref elts) => hir::PatTup(elts.iter().map(|x| lower_pat(x)).collect()), - PatBox(ref inner) => hir::PatBox(lower_pat(inner)), - PatRegion(ref inner, mutbl) => hir::PatRegion(lower_pat(inner), - lower_mutability(mutbl)), + PatTup(ref elts) => hir::PatTup(elts.iter().map(|x| lower_pat(_lctx, x)).collect()), + PatBox(ref inner) => hir::PatBox(lower_pat(_lctx, inner)), + PatRegion(ref inner, mutbl) => hir::PatRegion(lower_pat(_lctx, inner), + lower_mutability(_lctx, mutbl)), PatRange(ref e1, ref e2) => { - hir::PatRange(lower_expr(e1), lower_expr(e2)) - }, + hir::PatRange(lower_expr(_lctx, e1), lower_expr(_lctx, e2)) + } PatVec(ref before, ref slice, ref after) => { - hir::PatVec(before.iter().map(|x| lower_pat(x)).collect(), - slice.as_ref().map(|x| lower_pat(x)), - after.iter().map(|x| lower_pat(x)).collect()) + hir::PatVec(before.iter().map(|x| lower_pat(_lctx, x)).collect(), + slice.as_ref().map(|x| lower_pat(_lctx, x)), + after.iter().map(|x| lower_pat(_lctx, x)).collect()) } PatMac(_) => panic!("Shouldn't exist here"), }, - span: p.span, - }) + span: p.span, + }) +} + +// RAII utility for setting and unsetting the cached id. +struct CachedIdSetter<'a> { + reset: bool, + lctx: &'a LoweringContext<'a>, +} + +impl<'a> CachedIdSetter<'a> { + fn new(lctx: &'a LoweringContext, expr_id: NodeId) -> CachedIdSetter<'a> { + // Only reset the id if it was previously 0, i.e., was not cached. + // If it was cached, we are in a nested node, but our id count will + // still count towards the parent's count. + let reset_cached_id = lctx.cached_id.get() == 0; + + let id_cache: &mut HashMap<_, _> = &mut lctx.id_cache.borrow_mut(); + + if id_cache.contains_key(&expr_id) { + let cached_id = lctx.cached_id.get(); + if cached_id == 0 { + // We're entering a node where we need to track ids, but are not + // yet tracking. + lctx.cached_id.set(id_cache[&expr_id]); + lctx.gensym_key.set(id_cache[&expr_id]); + } else { + // We're already tracking - check that the tracked id is the same + // as the expected id. + assert!(cached_id == id_cache[&expr_id], "id mismatch"); + } + } else { + let next_id = lctx.id_assigner.peek_node_id(); + id_cache.insert(expr_id, next_id); + lctx.gensym_key.set(next_id); + } + + CachedIdSetter { + reset: reset_cached_id, + lctx: lctx, + } + } +} + +impl<'a> Drop for CachedIdSetter<'a> { + fn drop(&mut self) { + if self.reset { + self.lctx.cached_id.set(0); + self.lctx.gensym_key.set(0); + } + } } -pub fn lower_expr(e: &Expr) -> P { +pub fn lower_expr(lctx: &LoweringContext, e: &Expr) -> P { P(hir::Expr { - id: e.id, - node: match e.node { - ExprBox(ref e) => { - hir::ExprBox(lower_expr(e)) - } - ExprVec(ref exprs) => { - hir::ExprVec(exprs.iter().map(|x| lower_expr(x)).collect()) - } - ExprRepeat(ref expr, ref count) => { - hir::ExprRepeat(lower_expr(expr), lower_expr(count)) - } - ExprTup(ref elts) => hir::ExprTup(elts.iter().map(|x| lower_expr(x)).collect()), - ExprCall(ref f, ref args) => { - hir::ExprCall(lower_expr(f), - args.iter().map(|x| lower_expr(x)).collect()) - } - ExprMethodCall(i, ref tps, ref args) => { - hir::ExprMethodCall( - respan(i.span, i.node.name), - tps.iter().map(|x| lower_ty(x)).collect(), - args.iter().map(|x| lower_expr(x)).collect()) - } - ExprBinary(binop, ref lhs, ref rhs) => { - hir::ExprBinary(lower_binop(binop), - lower_expr(lhs), - lower_expr(rhs)) - } - ExprUnary(op, ref ohs) => { - hir::ExprUnary(lower_unop(op), lower_expr(ohs)) - } - ExprLit(ref l) => hir::ExprLit(P((**l).clone())), - ExprCast(ref expr, ref ty) => { - hir::ExprCast(lower_expr(expr), lower_ty(ty)) - } - ExprAddrOf(m, ref ohs) => hir::ExprAddrOf(lower_mutability(m), lower_expr(ohs)), - ExprIf(ref cond, ref tr, ref fl) => { - hir::ExprIf(lower_expr(cond), - lower_block(tr), - fl.as_ref().map(|x| lower_expr(x))) - } - ExprWhile(ref cond, ref body, opt_ident) => { - hir::ExprWhile(lower_expr(cond), - lower_block(body), - opt_ident) - } - ExprLoop(ref body, opt_ident) => { - hir::ExprLoop(lower_block(body), - opt_ident) - } - ExprMatch(ref expr, ref arms, ref source) => { - hir::ExprMatch(lower_expr(expr), - arms.iter().map(|x| lower_arm(x)).collect(), - lower_match_source(source)) - } - ExprClosure(capture_clause, ref decl, ref body) => { - hir::ExprClosure(lower_capture_clause(capture_clause), - lower_fn_decl(decl), - lower_block(body)) - } - ExprBlock(ref blk) => hir::ExprBlock(lower_block(blk)), - ExprAssign(ref el, ref er) => { - hir::ExprAssign(lower_expr(el), lower_expr(er)) - } - ExprAssignOp(op, ref el, ref er) => { - hir::ExprAssignOp(lower_binop(op), - lower_expr(el), - lower_expr(er)) - } - ExprField(ref el, ident) => { - hir::ExprField(lower_expr(el), respan(ident.span, ident.node.name)) - } - ExprTupField(ref el, ident) => { - hir::ExprTupField(lower_expr(el), ident) - } - ExprIndex(ref el, ref er) => { - hir::ExprIndex(lower_expr(el), lower_expr(er)) - } - ExprRange(ref e1, ref e2) => { - hir::ExprRange(e1.as_ref().map(|x| lower_expr(x)), - e2.as_ref().map(|x| lower_expr(x))) - } - ExprPath(ref qself, ref path) => { - let qself = qself.as_ref().map(|&QSelf { ref ty, position }| { - hir::QSelf { - ty: lower_ty(ty), - position: position + id: e.id, + node: match e.node { + // Issue #22181: + // Eventually a desugaring for `box EXPR` + // (similar to the desugaring above for `in PLACE BLOCK`) + // should go here, desugaring + // + // to: + // + // let mut place = BoxPlace::make_place(); + // let raw_place = Place::pointer(&mut place); + // let value = $value; + // unsafe { + // ::std::ptr::write(raw_place, value); + // Boxed::finalize(place) + // } + // + // But for now there are type-inference issues doing that. + ExprBox(ref e) => { + hir::ExprBox(lower_expr(lctx, e)) + } + + // Desugar ExprBox: `in (PLACE) EXPR` + ExprInPlace(ref placer, ref value_expr) => { + // to: + // + // let p = PLACE; + // let mut place = Placer::make_place(p); + // let raw_place = Place::pointer(&mut place); + // push_unsafe!({ + // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR )); + // InPlace::finalize(place) + // }) + let _old_cached = CachedIdSetter::new(lctx, e.id); + + let placer_expr = lower_expr(lctx, placer); + let value_expr = lower_expr(lctx, value_expr); + + let placer_ident = lctx.str_to_ident("placer"); + let agent_ident = lctx.str_to_ident("place"); + let p_ptr_ident = lctx.str_to_ident("p_ptr"); + + let make_place = ["ops", "Placer", "make_place"]; + let place_pointer = ["ops", "Place", "pointer"]; + let move_val_init = ["intrinsics", "move_val_init"]; + let inplace_finalize = ["ops", "InPlace", "finalize"]; + + let make_call = |lctx, p, args| { + let path = core_path(lctx, e.span, p); + let path = expr_path(lctx, path); + expr_call(lctx, e.span, path, args) + }; + + let mk_stmt_let = |lctx, bind, expr| stmt_let(lctx, e.span, false, bind, expr); + let mk_stmt_let_mut = |lctx, bind, expr| stmt_let(lctx, e.span, true, bind, expr); + + // let placer = ; + let s1 = mk_stmt_let(lctx, + placer_ident, + signal_block_expr(lctx, + vec![], + placer_expr, + e.span, + hir::PopUnstableBlock)); + + // let mut place = Placer::make_place(placer); + let s2 = { + let call = make_call(lctx, + &make_place, + vec![expr_ident(lctx, e.span, placer_ident)]); + mk_stmt_let_mut(lctx, agent_ident, call) + }; + + // let p_ptr = Place::pointer(&mut place); + let s3 = { + let args = vec![expr_mut_addr_of(lctx, + e.span, + expr_ident(lctx, e.span, agent_ident))]; + let call = make_call(lctx, &place_pointer, args); + mk_stmt_let(lctx, p_ptr_ident, call) + }; + + // pop_unsafe!(EXPR)); + let pop_unsafe_expr = + signal_block_expr(lctx, + vec![], + signal_block_expr(lctx, + vec![], + value_expr, + e.span, + hir::PopUnstableBlock), + e.span, + hir::PopUnsafeBlock(hir::CompilerGenerated)); + + // push_unsafe!({ + // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR )); + // InPlace::finalize(place) + // }) + let expr = { + let call_move_val_init = hir::StmtSemi(make_call(lctx, + &move_val_init, + vec![expr_ident(lctx, e.span, p_ptr_ident), + pop_unsafe_expr]), + lctx.next_id()); + let call_move_val_init = respan(e.span, call_move_val_init); + + let call = make_call(lctx, + &inplace_finalize, + vec![expr_ident(lctx, e.span, agent_ident)]); + signal_block_expr(lctx, + vec![P(call_move_val_init)], + call, + e.span, + hir::PushUnsafeBlock(hir::CompilerGenerated)) + }; + + return signal_block_expr(lctx, + vec![s1, s2, s3], + expr, + e.span, + hir::PushUnstableBlock); + } + + ExprVec(ref exprs) => { + hir::ExprVec(exprs.iter().map(|x| lower_expr(lctx, x)).collect()) + } + ExprRepeat(ref expr, ref count) => { + hir::ExprRepeat(lower_expr(lctx, expr), lower_expr(lctx, count)) + } + ExprTup(ref elts) => { + hir::ExprTup(elts.iter().map(|x| lower_expr(lctx, x)).collect()) + } + ExprCall(ref f, ref args) => { + hir::ExprCall(lower_expr(lctx, f), + args.iter().map(|x| lower_expr(lctx, x)).collect()) + } + ExprMethodCall(i, ref tps, ref args) => { + hir::ExprMethodCall(respan(i.span, i.node.name), + tps.iter().map(|x| lower_ty(lctx, x)).collect(), + args.iter().map(|x| lower_expr(lctx, x)).collect()) + } + ExprBinary(binop, ref lhs, ref rhs) => { + hir::ExprBinary(lower_binop(lctx, binop), + lower_expr(lctx, lhs), + lower_expr(lctx, rhs)) + } + ExprUnary(op, ref ohs) => { + hir::ExprUnary(lower_unop(lctx, op), lower_expr(lctx, ohs)) + } + ExprLit(ref l) => hir::ExprLit(P((**l).clone())), + ExprCast(ref expr, ref ty) => { + hir::ExprCast(lower_expr(lctx, expr), lower_ty(lctx, ty)) + } + ExprAddrOf(m, ref ohs) => { + hir::ExprAddrOf(lower_mutability(lctx, m), lower_expr(lctx, ohs)) + } + // More complicated than you might expect because the else branch + // might be `if let`. + ExprIf(ref cond, ref blk, ref else_opt) => { + let else_opt = else_opt.as_ref().map(|els| { + match els.node { + ExprIfLet(..) => { + let _old_cached = CachedIdSetter::new(lctx, e.id); + // wrap the if-let expr in a block + let span = els.span; + let blk = P(hir::Block { + stmts: vec![], + expr: Some(lower_expr(lctx, els)), + id: lctx.next_id(), + rules: hir::DefaultBlock, + span: span, + }); + expr_block(lctx, blk) } - }); - hir::ExprPath(qself, lower_path(path)) - } - ExprBreak(opt_ident) => hir::ExprBreak(opt_ident), - ExprAgain(opt_ident) => hir::ExprAgain(opt_ident), - ExprRet(ref e) => hir::ExprRet(e.as_ref().map(|x| lower_expr(x))), - ExprInlineAsm(InlineAsm { + _ => lower_expr(lctx, els), + } + }); + + hir::ExprIf(lower_expr(lctx, cond), + lower_block(lctx, blk), + else_opt) + } + ExprWhile(ref cond, ref body, opt_ident) => { + hir::ExprWhile(lower_expr(lctx, cond), + lower_block(lctx, body), + opt_ident) + } + ExprLoop(ref body, opt_ident) => { + hir::ExprLoop(lower_block(lctx, body), opt_ident) + } + ExprMatch(ref expr, ref arms) => { + hir::ExprMatch(lower_expr(lctx, expr), + arms.iter().map(|x| lower_arm(lctx, x)).collect(), + hir::MatchSource::Normal) + } + ExprClosure(capture_clause, ref decl, ref body) => { + hir::ExprClosure(lower_capture_clause(lctx, capture_clause), + lower_fn_decl(lctx, decl), + lower_block(lctx, body)) + } + ExprBlock(ref blk) => hir::ExprBlock(lower_block(lctx, blk)), + ExprAssign(ref el, ref er) => { + hir::ExprAssign(lower_expr(lctx, el), lower_expr(lctx, er)) + } + ExprAssignOp(op, ref el, ref er) => { + hir::ExprAssignOp(lower_binop(lctx, op), + lower_expr(lctx, el), + lower_expr(lctx, er)) + } + ExprField(ref el, ident) => { + hir::ExprField(lower_expr(lctx, el), + respan(ident.span, ident.node.name)) + } + ExprTupField(ref el, ident) => { + hir::ExprTupField(lower_expr(lctx, el), ident) + } + ExprIndex(ref el, ref er) => { + hir::ExprIndex(lower_expr(lctx, el), lower_expr(lctx, er)) + } + ExprRange(ref e1, ref e2) => { + hir::ExprRange(e1.as_ref().map(|x| lower_expr(lctx, x)), + e2.as_ref().map(|x| lower_expr(lctx, x))) + } + ExprPath(ref qself, ref path) => { + let qself = qself.as_ref().map(|&QSelf { ref ty, position }| { + hir::QSelf { + ty: lower_ty(lctx, ty), + position: position, + } + }); + hir::ExprPath(qself, lower_path(lctx, path)) + } + ExprBreak(opt_ident) => hir::ExprBreak(opt_ident), + ExprAgain(opt_ident) => hir::ExprAgain(opt_ident), + ExprRet(ref e) => hir::ExprRet(e.as_ref().map(|x| lower_expr(lctx, x))), + ExprInlineAsm(InlineAsm { ref inputs, ref outputs, ref asm, @@ -795,134 +1170,692 @@ pub fn lower_expr(e: &Expr) -> P { dialect, expn_id, }) => hir::ExprInlineAsm(hir::InlineAsm { - inputs: inputs.iter().map(|&(ref c, ref input)| { - (c.clone(), lower_expr(input)) - }).collect(), - outputs: outputs.iter().map(|&(ref c, ref out, ref is_rw)| { - (c.clone(), lower_expr(out), *is_rw) - }).collect(), - asm: asm.clone(), - asm_str_style: asm_str_style, - clobbers: clobbers.clone(), - volatile: volatile, - alignstack: alignstack, - dialect: dialect, - expn_id: expn_id, - }), - ExprStruct(ref path, ref fields, ref maybe_expr) => { - hir::ExprStruct(lower_path(path), - fields.iter().map(|x| lower_field(x)).collect(), - maybe_expr.as_ref().map(|x| lower_expr(x))) - }, - ExprParen(ref ex) => { - return lower_expr(ex); - } - ExprInPlace(..) | - ExprIfLet(..) | - ExprWhileLet(..) | - ExprForLoop(..) | - ExprMac(_) => panic!("Shouldn't exist here"), - }, - span: e.span, - }) + inputs: inputs.iter() + .map(|&(ref c, ref input)| (c.clone(), lower_expr(lctx, input))) + .collect(), + outputs: outputs.iter() + .map(|&(ref c, ref out, ref is_rw)| { + (c.clone(), lower_expr(lctx, out), *is_rw) + }) + .collect(), + asm: asm.clone(), + asm_str_style: asm_str_style, + clobbers: clobbers.clone(), + volatile: volatile, + alignstack: alignstack, + dialect: dialect, + expn_id: expn_id, + }), + ExprStruct(ref path, ref fields, ref maybe_expr) => { + hir::ExprStruct(lower_path(lctx, path), + fields.iter().map(|x| lower_field(lctx, x)).collect(), + maybe_expr.as_ref().map(|x| lower_expr(lctx, x))) + } + ExprParen(ref ex) => { + return lower_expr(lctx, ex); + } + + // Desugar ExprIfLet + // From: `if let = []` + ExprIfLet(ref pat, ref sub_expr, ref body, ref else_opt) => { + // to: + // + // match { + // => , + // [_ if => ,] + // _ => [ | ()] + // } + + let _old_cached = CachedIdSetter::new(lctx, e.id); + + // ` => ` + let pat_arm = { + let body_expr = expr_block(lctx, lower_block(lctx, body)); + arm(vec![lower_pat(lctx, pat)], body_expr) + }; + + // `[_ if => ,]` + let mut else_opt = else_opt.as_ref().map(|e| lower_expr(lctx, e)); + let else_if_arms = { + let mut arms = vec![]; + loop { + let else_opt_continue = else_opt.and_then(|els| { + els.and_then(|els| { + match els.node { + // else if + hir::ExprIf(cond, then, else_opt) => { + let pat_under = pat_wild(lctx, e.span); + arms.push(hir::Arm { + attrs: vec![], + pats: vec![pat_under], + guard: Some(cond), + body: expr_block(lctx, then), + }); + else_opt.map(|else_opt| (else_opt, true)) + } + _ => Some((P(els), false)), + } + }) + }); + match else_opt_continue { + Some((e, true)) => { + else_opt = Some(e); + } + Some((e, false)) => { + else_opt = Some(e); + break; + } + None => { + else_opt = None; + break; + } + } + } + arms + }; + + let contains_else_clause = else_opt.is_some(); + + // `_ => [ | ()]` + let else_arm = { + let pat_under = pat_wild(lctx, e.span); + let else_expr = else_opt.unwrap_or_else(|| expr_tuple(lctx, e.span, vec![])); + arm(vec![pat_under], else_expr) + }; + + let mut arms = Vec::with_capacity(else_if_arms.len() + 2); + arms.push(pat_arm); + arms.extend(else_if_arms); + arms.push(else_arm); + + let match_expr = expr(lctx, + e.span, + hir::ExprMatch(lower_expr(lctx, sub_expr), + arms, + hir::MatchSource::IfLetDesugar { + contains_else_clause: contains_else_clause, + })); + return match_expr; + } + + // Desugar ExprWhileLet + // From: `[opt_ident]: while let = ` + ExprWhileLet(ref pat, ref sub_expr, ref body, opt_ident) => { + // to: + // + // [opt_ident]: loop { + // match { + // => , + // _ => break + // } + // } + + let _old_cached = CachedIdSetter::new(lctx, e.id); + + // ` => ` + let pat_arm = { + let body_expr = expr_block(lctx, lower_block(lctx, body)); + arm(vec![lower_pat(lctx, pat)], body_expr) + }; + + // `_ => break` + let break_arm = { + let pat_under = pat_wild(lctx, e.span); + let break_expr = expr_break(lctx, e.span); + arm(vec![pat_under], break_expr) + }; + + // `match { ... }` + let arms = vec![pat_arm, break_arm]; + let match_expr = expr(lctx, + e.span, + hir::ExprMatch(lower_expr(lctx, sub_expr), + arms, + hir::MatchSource::WhileLetDesugar)); + + // `[opt_ident]: loop { ... }` + let loop_block = block_expr(lctx, match_expr); + return expr(lctx, e.span, hir::ExprLoop(loop_block, opt_ident)); + } + + // Desugar ExprForLoop + // From: `[opt_ident]: for in ` + ExprForLoop(ref pat, ref head, ref body, opt_ident) => { + // to: + // + // { + // let result = match ::std::iter::IntoIterator::into_iter() { + // mut iter => { + // [opt_ident]: loop { + // match ::std::iter::Iterator::next(&mut iter) { + // ::std::option::Option::Some() => , + // ::std::option::Option::None => break + // } + // } + // } + // }; + // result + // } + + let _old_cached = CachedIdSetter::new(lctx, e.id); + + // expand + let head = lower_expr(lctx, head); + + let iter = lctx.str_to_ident("iter"); + + // `::std::option::Option::Some() => ` + let pat_arm = { + let body_block = lower_block(lctx, body); + let body_span = body_block.span; + let body_expr = P(hir::Expr { + id: lctx.next_id(), + node: hir::ExprBlock(body_block), + span: body_span, + }); + let pat = lower_pat(lctx, pat); + let some_pat = pat_some(lctx, e.span, pat); + + arm(vec![some_pat], body_expr) + }; + + // `::std::option::Option::None => break` + let break_arm = { + let break_expr = expr_break(lctx, e.span); + + arm(vec![pat_none(lctx, e.span)], break_expr) + }; + + // `match ::std::iter::Iterator::next(&mut iter) { ... }` + let match_expr = { + let next_path = { + let strs = std_path(lctx, &["iter", "Iterator", "next"]); + + path_global(e.span, strs) + }; + let ref_mut_iter = expr_mut_addr_of(lctx, + e.span, + expr_ident(lctx, e.span, iter)); + let next_expr = expr_call(lctx, + e.span, + expr_path(lctx, next_path), + vec![ref_mut_iter]); + let arms = vec![pat_arm, break_arm]; + + expr(lctx, + e.span, + hir::ExprMatch(next_expr, arms, hir::MatchSource::ForLoopDesugar)) + }; + + // `[opt_ident]: loop { ... }` + let loop_block = block_expr(lctx, match_expr); + let loop_expr = expr(lctx, e.span, hir::ExprLoop(loop_block, opt_ident)); + + // `mut iter => { ... }` + let iter_arm = { + let iter_pat = pat_ident_binding_mode(lctx, + e.span, + iter, + hir::BindByValue(hir::MutMutable)); + arm(vec![iter_pat], loop_expr) + }; + + // `match ::std::iter::IntoIterator::into_iter() { ... }` + let into_iter_expr = { + let into_iter_path = { + let strs = std_path(lctx, &["iter", "IntoIterator", "into_iter"]); + + path_global(e.span, strs) + }; + + expr_call(lctx, + e.span, + expr_path(lctx, into_iter_path), + vec![head]) + }; + + let match_expr = expr_match(lctx, + e.span, + into_iter_expr, + vec![iter_arm], + hir::MatchSource::ForLoopDesugar); + + // `{ let result = ...; result }` + let result_ident = lctx.str_to_ident("result"); + return expr_block(lctx, + block_all(lctx, + e.span, + vec![stmt_let(lctx, + e.span, + false, + result_ident, + match_expr)], + Some(expr_ident(lctx, e.span, result_ident)))) + } + + ExprMac(_) => panic!("Shouldn't exist here"), + }, + span: e.span, + }) } -pub fn lower_stmt(s: &Stmt) -> P { +pub fn lower_stmt(_lctx: &LoweringContext, s: &Stmt) -> P { match s.node { StmtDecl(ref d, id) => { P(Spanned { - node: hir::StmtDecl(lower_decl(d), id), - span: s.span + node: hir::StmtDecl(lower_decl(_lctx, d), id), + span: s.span, }) } StmtExpr(ref e, id) => { P(Spanned { - node: hir::StmtExpr(lower_expr(e), id), - span: s.span + node: hir::StmtExpr(lower_expr(_lctx, e), id), + span: s.span, }) } StmtSemi(ref e, id) => { P(Spanned { - node: hir::StmtSemi(lower_expr(e), id), - span: s.span + node: hir::StmtSemi(lower_expr(_lctx, e), id), + span: s.span, }) } - StmtMac(..) => panic!("Shouldn't exist here") + StmtMac(..) => panic!("Shouldn't exist here"), } } -pub fn lower_match_source(m: &MatchSource) -> hir::MatchSource { - match *m { - MatchSource::Normal => hir::MatchSource::Normal, - MatchSource::IfLetDesugar { contains_else_clause } => { - hir::MatchSource::IfLetDesugar { contains_else_clause: contains_else_clause } - } - MatchSource::WhileLetDesugar => hir::MatchSource::WhileLetDesugar, - MatchSource::ForLoopDesugar => hir::MatchSource::ForLoopDesugar, - } -} - -pub fn lower_capture_clause(c: CaptureClause) -> hir::CaptureClause { +pub fn lower_capture_clause(_lctx: &LoweringContext, c: CaptureClause) -> hir::CaptureClause { match c { CaptureByValue => hir::CaptureByValue, CaptureByRef => hir::CaptureByRef, } } -pub fn lower_visibility(v: Visibility) -> hir::Visibility { +pub fn lower_visibility(_lctx: &LoweringContext, v: Visibility) -> hir::Visibility { match v { Public => hir::Public, Inherited => hir::Inherited, } } -pub fn lower_block_check_mode(b: &BlockCheckMode) -> hir::BlockCheckMode { +pub fn lower_block_check_mode(_lctx: &LoweringContext, b: &BlockCheckMode) -> hir::BlockCheckMode { match *b { DefaultBlock => hir::DefaultBlock, - UnsafeBlock(u) => hir::UnsafeBlock(lower_unsafe_source(u)), - PushUnsafeBlock(u) => hir::PushUnsafeBlock(lower_unsafe_source(u)), - PopUnsafeBlock(u) => hir::PopUnsafeBlock(lower_unsafe_source(u)), + UnsafeBlock(u) => hir::UnsafeBlock(lower_unsafe_source(_lctx, u)), + PushUnsafeBlock(u) => hir::PushUnsafeBlock(lower_unsafe_source(_lctx, u)), + PopUnsafeBlock(u) => hir::PopUnsafeBlock(lower_unsafe_source(_lctx, u)), } } -pub fn lower_pat_wild_kind(p: PatWildKind) -> hir::PatWildKind { +pub fn lower_pat_wild_kind(_lctx: &LoweringContext, p: PatWildKind) -> hir::PatWildKind { match p { PatWildSingle => hir::PatWildSingle, PatWildMulti => hir::PatWildMulti, } } -pub fn lower_binding_mode(b: &BindingMode) -> hir::BindingMode { +pub fn lower_binding_mode(_lctx: &LoweringContext, b: &BindingMode) -> hir::BindingMode { match *b { - BindByRef(m) => hir::BindByRef(lower_mutability(m)), - BindByValue(m) => hir::BindByValue(lower_mutability(m)), + BindByRef(m) => hir::BindByRef(lower_mutability(_lctx, m)), + BindByValue(m) => hir::BindByValue(lower_mutability(_lctx, m)), } } -pub fn lower_struct_field_kind(s: &StructFieldKind) -> hir::StructFieldKind { +pub fn lower_struct_field_kind(_lctx: &LoweringContext, + s: &StructFieldKind) + -> hir::StructFieldKind { match *s { - NamedField(ident, vis) => hir::NamedField(ident.name, lower_visibility(vis)), - UnnamedField(vis) => hir::UnnamedField(lower_visibility(vis)), + NamedField(ident, vis) => hir::NamedField(ident.name, lower_visibility(_lctx, vis)), + UnnamedField(vis) => hir::UnnamedField(lower_visibility(_lctx, vis)), } } -pub fn lower_unsafe_source(u: UnsafeSource) -> hir::UnsafeSource { +pub fn lower_unsafe_source(_lctx: &LoweringContext, u: UnsafeSource) -> hir::UnsafeSource { match u { CompilerGenerated => hir::CompilerGenerated, UserProvided => hir::UserProvided, } } -pub fn lower_impl_polarity(i: ImplPolarity) -> hir::ImplPolarity { +pub fn lower_impl_polarity(_lctx: &LoweringContext, i: ImplPolarity) -> hir::ImplPolarity { match i { ImplPolarity::Positive => hir::ImplPolarity::Positive, ImplPolarity::Negative => hir::ImplPolarity::Negative, } } -pub fn lower_trait_bound_modifier(f: TraitBoundModifier) -> hir::TraitBoundModifier { +pub fn lower_trait_bound_modifier(_lctx: &LoweringContext, + f: TraitBoundModifier) + -> hir::TraitBoundModifier { match f { TraitBoundModifier::None => hir::TraitBoundModifier::None, TraitBoundModifier::Maybe => hir::TraitBoundModifier::Maybe, } } + +// Helper methods for building HIR. + +fn arm(pats: Vec>, expr: P) -> hir::Arm { + hir::Arm { + attrs: vec!(), + pats: pats, + guard: None, + body: expr, + } +} + +fn expr_break(lctx: &LoweringContext, span: Span) -> P { + expr(lctx, span, hir::ExprBreak(None)) +} + +fn expr_call(lctx: &LoweringContext, + span: Span, + e: P, + args: Vec>) + -> P { + expr(lctx, span, hir::ExprCall(e, args)) +} + +fn expr_ident(lctx: &LoweringContext, span: Span, id: Ident) -> P { + expr_path(lctx, path_ident(span, id)) +} + +fn expr_mut_addr_of(lctx: &LoweringContext, span: Span, e: P) -> P { + expr(lctx, span, hir::ExprAddrOf(hir::MutMutable, e)) +} + +fn expr_path(lctx: &LoweringContext, path: hir::Path) -> P { + expr(lctx, path.span, hir::ExprPath(None, path)) +} + +fn expr_match(lctx: &LoweringContext, + span: Span, + arg: P, + arms: Vec, + source: hir::MatchSource) + -> P { + expr(lctx, + span, + hir::ExprMatch(arg, arms, source)) +} + +fn expr_block(lctx: &LoweringContext, b: P) -> P { + expr(lctx, b.span, hir::ExprBlock(b)) +} + +fn expr_tuple(lctx: &LoweringContext, sp: Span, exprs: Vec>) -> P { + expr(lctx, sp, hir::ExprTup(exprs)) +} + +fn expr(lctx: &LoweringContext, span: Span, node: hir::Expr_) -> P { + P(hir::Expr { + id: lctx.next_id(), + node: node, + span: span, + }) +} + +fn stmt_let(lctx: &LoweringContext, + sp: Span, + mutbl: bool, + ident: Ident, + ex: P) + -> P { + let pat = if mutbl { + pat_ident_binding_mode(lctx, sp, ident, hir::BindByValue(hir::MutMutable)) + } else { + pat_ident(lctx, sp, ident) + }; + let local = P(hir::Local { + pat: pat, + ty: None, + init: Some(ex), + id: lctx.next_id(), + span: sp, + }); + let decl = respan(sp, hir::DeclLocal(local)); + P(respan(sp, hir::StmtDecl(P(decl), lctx.next_id()))) +} + +fn block_expr(lctx: &LoweringContext, expr: P) -> P { + block_all(lctx, expr.span, Vec::new(), Some(expr)) +} + +fn block_all(lctx: &LoweringContext, + span: Span, + stmts: Vec>, + expr: Option>) + -> P { + P(hir::Block { + stmts: stmts, + expr: expr, + id: lctx.next_id(), + rules: hir::DefaultBlock, + span: span, + }) +} + +fn pat_some(lctx: &LoweringContext, span: Span, pat: P) -> P { + let some = std_path(lctx, &["option", "Option", "Some"]); + let path = path_global(span, some); + pat_enum(lctx, span, path, vec!(pat)) +} + +fn pat_none(lctx: &LoweringContext, span: Span) -> P { + let none = std_path(lctx, &["option", "Option", "None"]); + let path = path_global(span, none); + pat_enum(lctx, span, path, vec![]) +} + +fn pat_enum(lctx: &LoweringContext, + span: Span, + path: hir::Path, + subpats: Vec>) + -> P { + let pt = hir::PatEnum(path, Some(subpats)); + pat(lctx, span, pt) +} + +fn pat_ident(lctx: &LoweringContext, span: Span, ident: Ident) -> P { + pat_ident_binding_mode(lctx, span, ident, hir::BindByValue(hir::MutImmutable)) +} + +fn pat_ident_binding_mode(lctx: &LoweringContext, + span: Span, + ident: Ident, + bm: hir::BindingMode) + -> P { + let pat_ident = hir::PatIdent(bm, + Spanned { + span: span, + node: ident, + }, + None); + pat(lctx, span, pat_ident) +} + +fn pat_wild(lctx: &LoweringContext, span: Span) -> P { + pat(lctx, span, hir::PatWild(hir::PatWildSingle)) +} + +fn pat(lctx: &LoweringContext, span: Span, pat: hir::Pat_) -> P { + P(hir::Pat { + id: lctx.next_id(), + node: pat, + span: span, + }) +} + +fn path_ident(span: Span, id: Ident) -> hir::Path { + path(span, vec!(id)) +} + +fn path(span: Span, strs: Vec) -> hir::Path { + path_all(span, false, strs, Vec::new(), Vec::new(), Vec::new()) +} + +fn path_global(span: Span, strs: Vec) -> hir::Path { + path_all(span, true, strs, Vec::new(), Vec::new(), Vec::new()) +} + +fn path_all(sp: Span, + global: bool, + mut idents: Vec, + lifetimes: Vec, + types: Vec>, + bindings: Vec>) + -> hir::Path { + let last_identifier = idents.pop().unwrap(); + let mut segments: Vec = idents.into_iter() + .map(|ident| { + hir::PathSegment { + identifier: ident, + parameters: hir::PathParameters::none(), + } + }) + .collect(); + segments.push(hir::PathSegment { + identifier: last_identifier, + parameters: hir::AngleBracketedParameters(hir::AngleBracketedParameterData { + lifetimes: lifetimes, + types: OwnedSlice::from_vec(types), + bindings: OwnedSlice::from_vec(bindings), + }), + }); + hir::Path { + span: sp, + global: global, + segments: segments, + } +} + +fn std_path(lctx: &LoweringContext, components: &[&str]) -> Vec { + let mut v = Vec::new(); + if let Some(s) = lctx.crate_root { + v.push(str_to_ident(s)); + } + v.extend(components.iter().map(|s| str_to_ident(s))); + return v +} + +// Given suffix ["b","c","d"], returns path `::std::b::c::d` when +// `fld.cx.use_std`, and `::core::b::c::d` otherwise. +fn core_path(lctx: &LoweringContext, span: Span, components: &[&str]) -> hir::Path { + let idents = std_path(lctx, components); + path_global(span, idents) +} + +fn signal_block_expr(lctx: &LoweringContext, + stmts: Vec>, + expr: P, + span: Span, + rule: hir::BlockCheckMode) + -> P { + expr_block(lctx, + P(hir::Block { + rules: rule, + span: span, + id: lctx.next_id(), + stmts: stmts, + expr: Some(expr), + })) +} + + + +#[cfg(test)] +mod test { + use super::*; + use syntax::ast::{self, NodeId, NodeIdAssigner}; + use syntax::{parse, codemap}; + use syntax::fold::Folder; + use std::cell::Cell; + + struct MockAssigner { + next_id: Cell, + } + + impl MockAssigner { + fn new() -> MockAssigner { + MockAssigner { + next_id: Cell::new(0), + } + } + } + + trait FakeExtCtxt { + fn call_site(&self) -> codemap::Span; + fn cfg(&self) -> ast::CrateConfig; + fn ident_of(&self, st: &str) -> ast::Ident; + fn name_of(&self, st: &str) -> ast::Name; + fn parse_sess(&self) -> &parse::ParseSess; + } + + impl FakeExtCtxt for parse::ParseSess { + fn call_site(&self) -> codemap::Span { + codemap::Span { + lo: codemap::BytePos(0), + hi: codemap::BytePos(0), + expn_id: codemap::NO_EXPANSION, + } + } + fn cfg(&self) -> ast::CrateConfig { Vec::new() } + fn ident_of(&self, st: &str) -> ast::Ident { + parse::token::str_to_ident(st) + } + fn name_of(&self, st: &str) -> ast::Name { + parse::token::intern(st) + } + fn parse_sess(&self) -> &parse::ParseSess { self } + } + + impl NodeIdAssigner for MockAssigner { + fn next_node_id(&self) -> NodeId { + let result = self.next_id.get(); + self.next_id.set(result + 1); + result + } + + fn peek_node_id(&self) -> NodeId { + self.next_id.get() + } + } + + impl Folder for MockAssigner { + fn new_id(&mut self, old_id: NodeId) -> NodeId { + assert_eq!(old_id, ast::DUMMY_NODE_ID); + self.next_node_id() + } + } + + #[test] + fn test_preserves_ids() { + let cx = parse::ParseSess::new(); + let mut assigner = MockAssigner::new(); + + let ast_if_let = quote_expr!(&cx, if let Some(foo) = baz { bar(foo); }); + let ast_if_let = assigner.fold_expr(ast_if_let); + let ast_while_let = quote_expr!(&cx, while let Some(foo) = baz { bar(foo); }); + let ast_while_let = assigner.fold_expr(ast_while_let); + let ast_for = quote_expr!(&cx, for i in 0..10 { foo(i); }); + let ast_for = assigner.fold_expr(ast_for); + let ast_in = quote_expr!(&cx, in HEAP { foo() }); + let ast_in = assigner.fold_expr(ast_in); + + let lctx = LoweringContext::new(&assigner, None); + let hir1 = lower_expr(&lctx, &ast_if_let); + let hir2 = lower_expr(&lctx, &ast_if_let); + assert!(hir1 == hir2); + + let hir1 = lower_expr(&lctx, &ast_while_let); + let hir2 = lower_expr(&lctx, &ast_while_let); + assert!(hir1 == hir2); + + let hir1 = lower_expr(&lctx, &ast_for); + let hir2 = lower_expr(&lctx, &ast_for); + assert!(hir1 == hir2); + + let hir1 = lower_expr(&lctx, &ast_in); + let hir2 = lower_expr(&lctx, &ast_in); + assert!(hir1 == hir2); + } +}