// 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<HashMap<NodeId, NodeId>>,
+ // 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<u32>,
+ // Keep track of gensym'ed idents.
+ gensym_cache: RefCell<HashMap<(NodeId, &'static str), Ident>>,
+ // A copy of cached_id, but is also set to an id while it is being cached.
+ gensym_key: Cell<u32>,
+}
+
+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
+ }
-pub fn lower_view_path(view_path: &ViewPath) -> P<hir::ViewPath> {
+ 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(_lctx: &LoweringContext, view_path: &ViewPath) -> P<hir::ViewPath> {
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),
+ hir::ViewPathList(lower_path(_lctx, path),
path_list_idents.iter()
.map(|path_list_ident| {
Spanned {
})
}
-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<hir::Decl> {
+pub fn lower_decl(_lctx: &LoweringContext, d: &Decl) -> P<hir::Decl> {
match d.node {
DeclLocal(ref l) => P(Spanned {
- node: hir::DeclLocal(lower_local(l)),
+ node: hir::DeclLocal(lower_local(_lctx, l)),
span: d.span,
}),
DeclItem(ref it) => P(Spanned {
- node: hir::DeclItem(lower_item(it)),
+ node: hir::DeclItem(lower_item(_lctx, it)),
span: d.span,
}),
}
}
-pub fn lower_ty_binding(b: &TypeBinding) -> P<hir::TypeBinding> {
+pub fn lower_ty_binding(_lctx: &LoweringContext, b: &TypeBinding) -> P<hir::TypeBinding> {
P(hir::TypeBinding {
id: b.id,
name: b.ident.name,
- ty: lower_ty(&b.ty),
+ ty: lower_ty(_lctx, &b.ty),
span: b.span,
})
}
-pub fn lower_ty(t: &Ty) -> P<hir::Ty> {
+pub fn lower_ty(_lctx: &LoweringContext, t: &Ty) -> P<hir::Ty> {
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),
+ 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."),
},
})
}
-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<hir::Variant> {
+pub fn lower_variant(_lctx: &LoweringContext, v: &Variant) -> P<hir::Variant> {
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
.map(|&PathSegment { identifier, ref parameters }| {
hir::PathSegment {
identifier: identifier,
- parameters: lower_path_parameters(parameters),
+ parameters: lower_path_parameters(_lctx, parameters),
}
})
.collect(),
}
}
-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<hir::Local> {
+pub fn lower_local(_lctx: &LoweringContext, l: &Local) -> P<hir::Local> {
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)),
+ 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),
+ 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 {
+pub fn lower_explicit_self(_lctx: &LoweringContext, s: &ExplicitSelf) -> hir::ExplicitSelf {
Spanned {
- node: lower_explicit_self_underscore(&s.node),
+ node: lower_explicit_self_underscore(_lctx, &s.node),
span: s.span,
}
}
-pub fn lower_arg(arg: &Arg) -> hir::Arg {
+pub fn lower_arg(_lctx: &LoweringContext, arg: &Arg) -> hir::Arg {
hir::Arg {
id: arg.id,
- pat: lower_pat(&arg.pat),
- ty: lower_ty(&arg.ty),
+ pat: lower_pat(_lctx, &arg.pat),
+ ty: lower_ty(_lctx, &arg.ty),
}
}
-pub fn lower_fn_decl(decl: &FnDecl) -> P<hir::FnDecl> {
+pub fn lower_fn_decl(_lctx: &LoweringContext, decl: &FnDecl) -> P<hir::FnDecl> {
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),
},
})
}
-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<TyParam>) -> OwnedSlice<hir::TyParam> {
- tps.iter().map(|tp| lower_ty_param(tp)).collect()
+pub fn lower_ty_params(_lctx: &LoweringContext,
+ tps: &OwnedSlice<TyParam>)
+ -> OwnedSlice<hir::TyParam> {
+ tps.iter().map(|tp| lower_ty_param(_lctx, tp)).collect()
}
-pub fn lower_lifetime(l: &Lifetime) -> hir::Lifetime {
+pub fn lower_lifetime(_lctx: &LoweringContext, l: &Lifetime) -> hir::Lifetime {
hir::Lifetime {
id: l.id,
name: l.name,
}
}
-pub fn lower_lifetime_def(l: &LifetimeDef) -> hir::LifetimeDef {
+pub fn lower_lifetime_def(_lctx: &LoweringContext, l: &LifetimeDef) -> hir::LifetimeDef {
hir::LifetimeDef {
- lifetime: lower_lifetime(&l.lifetime),
- bounds: lower_lifetimes(&l.bounds),
+ lifetime: lower_lifetime(_lctx, &l.lifetime),
+ bounds: lower_lifetimes(_lctx, &l.bounds),
}
}
-pub fn lower_lifetimes(lts: &Vec<Lifetime>) -> Vec<hir::Lifetime> {
- lts.iter().map(|l| lower_lifetime(l)).collect()
+pub fn lower_lifetimes(_lctx: &LoweringContext, lts: &Vec<Lifetime>) -> Vec<hir::Lifetime> {
+ lts.iter().map(|l| lower_lifetime(_lctx, l)).collect()
}
-pub fn lower_lifetime_defs(lts: &Vec<LifetimeDef>) -> Vec<hir::LifetimeDef> {
- lts.iter().map(|l| lower_lifetime_def(l)).collect()
+pub fn lower_lifetime_defs(_lctx: &LoweringContext,
+ lts: &Vec<LifetimeDef>)
+ -> Vec<hir::LifetimeDef> {
+ lts.iter().map(|l| lower_lifetime_def(_lctx, l)).collect()
}
-pub fn lower_opt_lifetime(o_lt: &Option<Lifetime>) -> Option<hir::Lifetime> {
- o_lt.as_ref().map(|lt| lower_lifetime(lt))
+pub fn lower_opt_lifetime(_lctx: &LoweringContext,
+ o_lt: &Option<Lifetime>)
+ -> Option<hir::Lifetime> {
+ 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))
+ .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(),
+ 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,
})
}
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,
span}) => {
hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
id: id,
- path: lower_path(path),
- ty: lower_ty(ty),
+ path: lower_path(_lctx, path),
+ ty: lower_ty(_lctx, ty),
span: span,
})
}
}
}
-pub fn lower_struct_def(sd: &StructDef) -> P<hir::StructDef> {
+pub fn lower_struct_def(_lctx: &LoweringContext, sd: &StructDef) -> P<hir::StructDef> {
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 {
+pub fn lower_trait_ref(_lctx: &LoweringContext, p: &TraitRef) -> hir::TraitRef {
hir::TraitRef {
- path: lower_path(&p.path),
+ 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),
+ expr: lower_expr(_lctx, &f.expr),
span: f.span,
}
}
-pub fn lower_mt(mt: &MutTy) -> hir::MutTy {
+pub fn lower_mt(_lctx: &LoweringContext, mt: &MutTy) -> hir::MutTy {
hir::MutTy {
- ty: lower_ty(&mt.ty),
- mutbl: lower_mutability(mt.mutbl),
+ ty: lower_ty(_lctx, &mt.ty),
+ mutbl: lower_mutability(_lctx, mt.mutbl),
}
}
-pub fn lower_opt_bounds(b: &Option<OwnedSlice<TyParamBound>>)
+pub fn lower_opt_bounds(_lctx: &LoweringContext,
+ b: &Option<OwnedSlice<TyParamBound>>)
-> Option<OwnedSlice<hir::TyParamBound>> {
- 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<hir::Block> {
+pub fn lower_block(_lctx: &LoweringContext, b: &Block) -> P<hir::Block> {
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),
+ hir::ItemFn(lower_fn_decl(_lctx, decl),
+ lower_unsafety(_lctx, unsafety),
+ lower_constness(_lctx, constness),
abi,
- lower_generics(generics),
- lower_block(body))
+ lower_generics(_lctx, generics),
+ lower_block(_lctx, body))
}
- ItemMod(ref m) => hir::ItemMod(lower_mod(m)),
- ItemForeignMod(ref nm) => hir::ItemForeignMod(lower_foreign_mod(nm)),
+ 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))
+ .map(|x| lower_variant(_lctx, x))
.collect(),
},
- lower_generics(generics))
+ 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)
}
}
}
-pub fn lower_trait_item(i: &TraitItem) -> P<hir::TraitItem> {
+pub fn lower_trait_item(_lctx: &LoweringContext, i: &TraitItem) -> P<hir::TraitItem> {
P(hir::TraitItem {
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,
})
}
-pub fn lower_impl_item(i: &ImplItem) -> P<hir::ImplItem> {
+pub fn lower_impl_item(_lctx: &LoweringContext, i: &ImplItem) -> P<hir::ImplItem> {
P(hir::ImplItem {
id: i.id,
name: i.ident.name,
attrs: i.attrs.clone(),
- vis: lower_visibility(i.vis),
+ 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,
})
}
-pub fn lower_mod(m: &Mod) -> hir::Mod {
+pub fn lower_mod(_lctx: &LoweringContext, m: &Mod) -> hir::Mod {
hir::Mod {
inner: m.inner,
- items: m.items.iter().map(|x| lower_item(x)).collect(),
+ 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(),
}
// fold one item into possibly many items
-pub fn lower_item(i: &Item) -> P<hir::Item> {
- P(lower_item_simple(i))
+pub fn lower_item(_lctx: &LoweringContext, i: &Item) -> P<hir::Item> {
+ 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<hir::ForeignItem> {
+pub fn lower_foreign_item(_lctx: &LoweringContext, i: &ForeignItem) -> P<hir::ForeignItem> {
P(hir::ForeignItem {
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),
+ 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,
}
}
-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,
}
}
-pub fn lower_pat(p: &Pat) -> P<hir::Pat> {
+pub fn lower_pat(_lctx: &LoweringContext, p: &Pat) -> P<hir::Pat> {
P(hir::Pat {
id: p.id,
node: match p.node {
- PatWild(k) => hir::PatWild(lower_pat_wild_kind(k)),
+ PatWild(k) => hir::PatWild(lower_pat_wild_kind(_lctx, k)),
PatIdent(ref binding_mode, pth1, ref sub) => {
- hir::PatIdent(lower_binding_mode(binding_mode),
+ hir::PatIdent(lower_binding_mode(_lctx, binding_mode),
pth1,
- sub.as_ref().map(|x| lower_pat(x)))
+ 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 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(&f.node.pat),
+ 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"),
},
})
}
-pub fn lower_expr(e: &Expr) -> P<hir::Expr> {
+// 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(lctx: &LoweringContext, e: &Expr) -> P<hir::Expr> {
P(hir::Expr {
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(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 = <placer_expr> ;
+ 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(x)).collect())
+ hir::ExprVec(exprs.iter().map(|x| lower_expr(lctx, x)).collect())
}
ExprRepeat(ref expr, ref count) => {
- hir::ExprRepeat(lower_expr(expr), lower_expr(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())
}
- 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())
+ 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(x)).collect(),
- args.iter().map(|x| lower_expr(x)).collect())
+ 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(binop), lower_expr(lhs), lower_expr(rhs))
+ hir::ExprBinary(lower_binop(lctx, binop),
+ lower_expr(lctx, lhs),
+ lower_expr(lctx, rhs))
}
ExprUnary(op, ref ohs) => {
- hir::ExprUnary(lower_unop(op), lower_expr(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(expr), lower_ty(ty))
+ hir::ExprCast(lower_expr(lctx, expr), lower_ty(lctx, 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)))
+ 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)
+ }
+ _ => 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(cond), lower_block(body), opt_ident)
+ hir::ExprWhile(lower_expr(lctx, cond),
+ lower_block(lctx, body),
+ opt_ident)
}
ExprLoop(ref body, opt_ident) => {
- hir::ExprLoop(lower_block(body), opt_ident)
+ hir::ExprLoop(lower_block(lctx, 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))
+ 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(capture_clause),
- lower_fn_decl(decl),
- lower_block(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(blk)),
+ ExprBlock(ref blk) => hir::ExprBlock(lower_block(lctx, blk)),
ExprAssign(ref el, ref er) => {
- hir::ExprAssign(lower_expr(el), lower_expr(er))
+ hir::ExprAssign(lower_expr(lctx, el), lower_expr(lctx, er))
}
ExprAssignOp(op, ref el, ref er) => {
- hir::ExprAssignOp(lower_binop(op), lower_expr(el), lower_expr(er))
+ hir::ExprAssignOp(lower_binop(lctx, op),
+ lower_expr(lctx, el),
+ lower_expr(lctx, er))
}
ExprField(ref el, ident) => {
- hir::ExprField(lower_expr(el), respan(ident.span, ident.node.name))
+ hir::ExprField(lower_expr(lctx, el),
+ respan(ident.span, ident.node.name))
}
ExprTupField(ref el, ident) => {
- hir::ExprTupField(lower_expr(el), ident)
+ hir::ExprTupField(lower_expr(lctx, el), ident)
}
ExprIndex(ref el, ref er) => {
- hir::ExprIndex(lower_expr(el), lower_expr(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(x)),
- e2.as_ref().map(|x| lower_expr(x)))
+ 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(ty),
+ ty: lower_ty(lctx, ty),
position: position,
}
});
- hir::ExprPath(qself, lower_path(path))
+ 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(x))),
+ ExprRet(ref e) => hir::ExprRet(e.as_ref().map(|x| lower_expr(lctx, x))),
ExprInlineAsm(InlineAsm {
ref inputs,
ref outputs,
expn_id,
}) => hir::ExprInlineAsm(hir::InlineAsm {
inputs: inputs.iter()
- .map(|&(ref c, ref input)| (c.clone(), lower_expr(input)))
+ .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(out), *is_rw)
+ (c.clone(), lower_expr(lctx, out), *is_rw)
})
.collect(),
asm: asm.clone(),
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)))
+ 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(ex);
+ return lower_expr(lctx, ex);
+ }
+
+ // Desugar ExprIfLet
+ // From: `if let <pat> = <sub_expr> <body> [<else_opt>]`
+ ExprIfLet(ref pat, ref sub_expr, ref body, ref else_opt) => {
+ // to:
+ //
+ // match <sub_expr> {
+ // <pat> => <body>,
+ // [_ if <else_opt_if_cond> => <else_opt_if_body>,]
+ // _ => [<else_opt> | ()]
+ // }
+
+ let _old_cached = CachedIdSetter::new(lctx, e.id);
+
+ // `<pat> => <body>`
+ let pat_arm = {
+ let body_expr = expr_block(lctx, lower_block(lctx, body));
+ arm(vec![lower_pat(lctx, pat)], body_expr)
+ };
+
+ // `[_ if <else_opt_if_cond> => <else_opt_if_body>,]`
+ 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();
+
+ // `_ => [<else_opt> | ()]`
+ 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 <pat> = <sub_expr> <body>`
+ ExprWhileLet(ref pat, ref sub_expr, ref body, opt_ident) => {
+ // to:
+ //
+ // [opt_ident]: loop {
+ // match <sub_expr> {
+ // <pat> => <body>,
+ // _ => break
+ // }
+ // }
+
+ let _old_cached = CachedIdSetter::new(lctx, e.id);
+
+ // `<pat> => <body>`
+ 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 <sub_expr> { ... }`
+ 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 <pat> in <head> <body>`
+ ExprForLoop(ref pat, ref head, ref body, opt_ident) => {
+ // to:
+ //
+ // {
+ // let result = match ::std::iter::IntoIterator::into_iter(<head>) {
+ // mut iter => {
+ // [opt_ident]: loop {
+ // match ::std::iter::Iterator::next(&mut iter) {
+ // ::std::option::Option::Some(<pat>) => <body>,
+ // ::std::option::Option::None => break
+ // }
+ // }
+ // }
+ // };
+ // result
+ // }
+
+ let _old_cached = CachedIdSetter::new(lctx, e.id);
+
+ // expand <head>
+ let head = lower_expr(lctx, head);
+
+ let iter = lctx.str_to_ident("iter");
+
+ // `::std::option::Option::Some(<pat>) => <body>`
+ 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(<head>) { ... }`
+ 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))))
}
- ExprInPlace(..) |
- ExprIfLet(..) |
- ExprWhileLet(..) |
- ExprForLoop(..) |
+
ExprMac(_) => panic!("Shouldn't exist here"),
},
span: e.span,
})
}
-pub fn lower_stmt(s: &Stmt) -> P<hir::Stmt> {
+pub fn lower_stmt(_lctx: &LoweringContext, s: &Stmt) -> P<hir::Stmt> {
match s.node {
StmtDecl(ref d, id) => {
P(Spanned {
- node: hir::StmtDecl(lower_decl(d), id),
+ node: hir::StmtDecl(lower_decl(_lctx, d), id),
span: s.span,
})
}
StmtExpr(ref e, id) => {
P(Spanned {
- node: hir::StmtExpr(lower_expr(e), id),
+ node: hir::StmtExpr(lower_expr(_lctx, e), id),
span: s.span,
})
}
StmtSemi(ref e, id) => {
P(Spanned {
- node: hir::StmtSemi(lower_expr(e), id),
+ node: hir::StmtSemi(lower_expr(_lctx, e), id),
span: s.span,
})
}
}
}
-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<P<hir::Pat>>, expr: P<hir::Expr>) -> hir::Arm {
+ hir::Arm {
+ attrs: vec!(),
+ pats: pats,
+ guard: None,
+ body: expr,
+ }
+}
+
+fn expr_break(lctx: &LoweringContext, span: Span) -> P<hir::Expr> {
+ expr(lctx, span, hir::ExprBreak(None))
+}
+
+fn expr_call(lctx: &LoweringContext,
+ span: Span,
+ e: P<hir::Expr>,
+ args: Vec<P<hir::Expr>>)
+ -> P<hir::Expr> {
+ expr(lctx, span, hir::ExprCall(e, args))
+}
+
+fn expr_ident(lctx: &LoweringContext, span: Span, id: Ident) -> P<hir::Expr> {
+ expr_path(lctx, path_ident(span, id))
+}
+
+fn expr_mut_addr_of(lctx: &LoweringContext, span: Span, e: P<hir::Expr>) -> P<hir::Expr> {
+ expr(lctx, span, hir::ExprAddrOf(hir::MutMutable, e))
+}
+
+fn expr_path(lctx: &LoweringContext, path: hir::Path) -> P<hir::Expr> {
+ expr(lctx, path.span, hir::ExprPath(None, path))
+}
+
+fn expr_match(lctx: &LoweringContext,
+ span: Span,
+ arg: P<hir::Expr>,
+ arms: Vec<hir::Arm>,
+ source: hir::MatchSource)
+ -> P<hir::Expr> {
+ expr(lctx,
+ span,
+ hir::ExprMatch(arg, arms, source))
+}
+
+fn expr_block(lctx: &LoweringContext, b: P<hir::Block>) -> P<hir::Expr> {
+ expr(lctx, b.span, hir::ExprBlock(b))
+}
+
+fn expr_tuple(lctx: &LoweringContext, sp: Span, exprs: Vec<P<hir::Expr>>) -> P<hir::Expr> {
+ expr(lctx, sp, hir::ExprTup(exprs))
+}
+
+fn expr(lctx: &LoweringContext, span: Span, node: hir::Expr_) -> P<hir::Expr> {
+ P(hir::Expr {
+ id: lctx.next_id(),
+ node: node,
+ span: span,
+ })
+}
+
+fn stmt_let(lctx: &LoweringContext,
+ sp: Span,
+ mutbl: bool,
+ ident: Ident,
+ ex: P<hir::Expr>)
+ -> P<hir::Stmt> {
+ 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<hir::Expr>) -> P<hir::Block> {
+ block_all(lctx, expr.span, Vec::new(), Some(expr))
+}
+
+fn block_all(lctx: &LoweringContext,
+ span: Span,
+ stmts: Vec<P<hir::Stmt>>,
+ expr: Option<P<hir::Expr>>)
+ -> P<hir::Block> {
+ 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<hir::Pat>) -> P<hir::Pat> {
+ 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<hir::Pat> {
+ 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<hir::Pat>>)
+ -> P<hir::Pat> {
+ let pt = hir::PatEnum(path, Some(subpats));
+ pat(lctx, span, pt)
+}
+
+fn pat_ident(lctx: &LoweringContext, span: Span, ident: Ident) -> P<hir::Pat> {
+ 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<hir::Pat> {
+ 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<hir::Pat> {
+ pat(lctx, span, hir::PatWild(hir::PatWildSingle))
+}
+
+fn pat(lctx: &LoweringContext, span: Span, pat: hir::Pat_) -> P<hir::Pat> {
+ 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<Ident>) -> hir::Path {
+ path_all(span, false, strs, Vec::new(), Vec::new(), Vec::new())
+}
+
+fn path_global(span: Span, strs: Vec<Ident>) -> hir::Path {
+ path_all(span, true, strs, Vec::new(), Vec::new(), Vec::new())
+}
+
+fn path_all(sp: Span,
+ global: bool,
+ mut idents: Vec<Ident>,
+ lifetimes: Vec<hir::Lifetime>,
+ types: Vec<P<hir::Ty>>,
+ bindings: Vec<P<hir::TypeBinding>>)
+ -> hir::Path {
+ let last_identifier = idents.pop().unwrap();
+ let mut segments: Vec<hir::PathSegment> = 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<Ident> {
+ 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<P<hir::Stmt>>,
+ expr: P<hir::Expr>,
+ span: Span,
+ rule: hir::BlockCheckMode)
+ -> P<hir::Expr> {
+ 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<NodeId>,
+ }
+
+ 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);
+ }
+}
projects / rust.git / blobdiff