1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![allow(non_camel_case_types)]
13 pub use self::terr_vstore_kind::*;
14 pub use self::type_err::*;
15 pub use self::BuiltinBound::*;
16 pub use self::InferTy::*;
17 pub use self::InferRegion::*;
18 pub use self::ImplOrTraitItemId::*;
19 pub use self::UnboxedClosureKind::*;
20 pub use self::ast_ty_to_ty_cache_entry::*;
21 pub use self::Variance::*;
22 pub use self::AutoAdjustment::*;
23 pub use self::Representability::*;
24 pub use self::UnsizeKind::*;
25 pub use self::AutoRef::*;
26 pub use self::ExprKind::*;
27 pub use self::DtorKind::*;
28 pub use self::ExplicitSelfCategory::*;
29 pub use self::FnOutput::*;
30 pub use self::Region::*;
31 pub use self::ImplOrTraitItemContainer::*;
32 pub use self::BorrowKind::*;
33 pub use self::ImplOrTraitItem::*;
34 pub use self::BoundRegion::*;
36 pub use self::IntVarValue::*;
37 pub use self::ExprAdjustment::*;
38 pub use self::vtable_origin::*;
39 pub use self::MethodOrigin::*;
40 pub use self::CopyImplementationError::*;
45 use metadata::csearch;
47 use middle::const_eval;
48 use middle::def::{self, DefMap, ExportMap};
49 use middle::dependency_format;
50 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem};
51 use middle::lang_items::{FnOnceTraitLangItem, TyDescStructLangItem};
52 use middle::mem_categorization as mc;
54 use middle::resolve_lifetime;
56 use middle::stability;
57 use middle::subst::{self, Subst, Substs, VecPerParamSpace};
60 use middle::ty_fold::{self, TypeFoldable, TypeFolder};
61 use middle::ty_walk::TypeWalker;
62 use util::ppaux::{note_and_explain_region, bound_region_ptr_to_string};
63 use util::ppaux::ty_to_string;
64 use util::ppaux::{Repr, UserString};
65 use util::common::{memoized, ErrorReported};
66 use util::nodemap::{NodeMap, NodeSet, DefIdMap, DefIdSet};
67 use util::nodemap::{FnvHashMap};
69 use arena::TypedArena;
70 use std::borrow::{BorrowFrom, Cow};
71 use std::cell::{Cell, RefCell};
72 use std::cmp::{self, Ordering};
73 use std::fmt::{self, Show};
74 use std::hash::{Hash, Writer, SipHasher, Hasher};
79 use collections::enum_set::{EnumSet, CLike};
80 use std::collections::{HashMap, HashSet};
82 use syntax::ast::{CrateNum, DefId, Ident, ItemTrait, LOCAL_CRATE};
83 use syntax::ast::{MutImmutable, MutMutable, Name, NamedField, NodeId};
84 use syntax::ast::{Onceness, StmtExpr, StmtSemi, StructField, UnnamedField};
85 use syntax::ast::{Visibility};
86 use syntax::ast_util::{self, is_local, lit_is_str, local_def, PostExpansionMethod};
87 use syntax::attr::{self, AttrMetaMethods};
88 use syntax::codemap::Span;
89 use syntax::parse::token::{self, InternedString, special_idents};
90 use syntax::{ast, ast_map};
94 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
98 /// The complete set of all analyses described in this module. This is
99 /// produced by the driver and fed to trans and later passes.
100 pub struct CrateAnalysis<'tcx> {
101 pub export_map: ExportMap,
102 pub exported_items: middle::privacy::ExportedItems,
103 pub public_items: middle::privacy::PublicItems,
104 pub ty_cx: ty::ctxt<'tcx>,
105 pub reachable: NodeSet,
107 pub glob_map: Option<GlobMap>,
110 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
111 pub struct field<'tcx> {
116 #[derive(Clone, Copy, Show)]
117 pub enum ImplOrTraitItemContainer {
118 TraitContainer(ast::DefId),
119 ImplContainer(ast::DefId),
122 impl ImplOrTraitItemContainer {
123 pub fn id(&self) -> ast::DefId {
125 TraitContainer(id) => id,
126 ImplContainer(id) => id,
131 #[derive(Clone, Show)]
132 pub enum ImplOrTraitItem<'tcx> {
133 MethodTraitItem(Rc<Method<'tcx>>),
134 TypeTraitItem(Rc<AssociatedType>),
137 impl<'tcx> ImplOrTraitItem<'tcx> {
138 fn id(&self) -> ImplOrTraitItemId {
140 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
141 TypeTraitItem(ref associated_type) => {
142 TypeTraitItemId(associated_type.def_id)
147 pub fn def_id(&self) -> ast::DefId {
149 MethodTraitItem(ref method) => method.def_id,
150 TypeTraitItem(ref associated_type) => associated_type.def_id,
154 pub fn name(&self) -> ast::Name {
156 MethodTraitItem(ref method) => method.name,
157 TypeTraitItem(ref associated_type) => associated_type.name,
161 pub fn container(&self) -> ImplOrTraitItemContainer {
163 MethodTraitItem(ref method) => method.container,
164 TypeTraitItem(ref associated_type) => associated_type.container,
168 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
170 MethodTraitItem(ref m) => Some((*m).clone()),
171 TypeTraitItem(_) => None
176 #[derive(Clone, Copy, Show)]
177 pub enum ImplOrTraitItemId {
178 MethodTraitItemId(ast::DefId),
179 TypeTraitItemId(ast::DefId),
182 impl ImplOrTraitItemId {
183 pub fn def_id(&self) -> ast::DefId {
185 MethodTraitItemId(def_id) => def_id,
186 TypeTraitItemId(def_id) => def_id,
191 #[derive(Clone, Show)]
192 pub struct Method<'tcx> {
194 pub generics: ty::Generics<'tcx>,
195 pub fty: BareFnTy<'tcx>,
196 pub explicit_self: ExplicitSelfCategory,
197 pub vis: ast::Visibility,
198 pub def_id: ast::DefId,
199 pub container: ImplOrTraitItemContainer,
201 // If this method is provided, we need to know where it came from
202 pub provided_source: Option<ast::DefId>
205 impl<'tcx> Method<'tcx> {
206 pub fn new(name: ast::Name,
207 generics: ty::Generics<'tcx>,
209 explicit_self: ExplicitSelfCategory,
210 vis: ast::Visibility,
212 container: ImplOrTraitItemContainer,
213 provided_source: Option<ast::DefId>)
219 explicit_self: explicit_self,
222 container: container,
223 provided_source: provided_source
227 pub fn container_id(&self) -> ast::DefId {
228 match self.container {
229 TraitContainer(id) => id,
230 ImplContainer(id) => id,
235 #[derive(Clone, Copy, Show)]
236 pub struct AssociatedType {
238 pub vis: ast::Visibility,
239 pub def_id: ast::DefId,
240 pub container: ImplOrTraitItemContainer,
243 #[derive(Clone, Copy, PartialEq, Eq, Hash, Show)]
244 pub struct mt<'tcx> {
246 pub mutbl: ast::Mutability,
249 #[derive(Clone, Copy, Show)]
250 pub struct field_ty {
253 pub vis: ast::Visibility,
254 pub origin: ast::DefId, // The DefId of the struct in which the field is declared.
257 // Contains information needed to resolve types and (in the future) look up
258 // the types of AST nodes.
259 #[derive(Copy, PartialEq, Eq, Hash)]
260 pub struct creader_cache_key {
267 pub enum ast_ty_to_ty_cache_entry<'tcx> {
268 atttce_unresolved, /* not resolved yet */
269 atttce_resolved(Ty<'tcx>) /* resolved to a type, irrespective of region */
272 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
273 pub struct ItemVariances {
274 pub types: VecPerParamSpace<Variance>,
275 pub regions: VecPerParamSpace<Variance>,
278 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Show, Copy)]
280 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
281 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
282 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
283 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
286 #[derive(Clone, Show)]
287 pub enum AutoAdjustment<'tcx> {
288 AdjustReifyFnPointer(ast::DefId), // go from a fn-item type to a fn-pointer type
289 AdjustDerefRef(AutoDerefRef<'tcx>)
292 #[derive(Clone, PartialEq, Show)]
293 pub enum UnsizeKind<'tcx> {
294 // [T, ..n] -> [T], the uint field is n.
296 // An unsize coercion applied to the tail field of a struct.
297 // The uint is the index of the type parameter which is unsized.
298 UnsizeStruct(Box<UnsizeKind<'tcx>>, uint),
299 UnsizeVtable(TyTrait<'tcx>, /* the self type of the trait */ Ty<'tcx>)
302 #[derive(Clone, Show)]
303 pub struct AutoDerefRef<'tcx> {
304 pub autoderefs: uint,
305 pub autoref: Option<AutoRef<'tcx>>
308 #[derive(Clone, PartialEq, Show)]
309 pub enum AutoRef<'tcx> {
310 /// Convert from T to &T
311 /// The third field allows us to wrap other AutoRef adjustments.
312 AutoPtr(Region, ast::Mutability, Option<Box<AutoRef<'tcx>>>),
314 /// Convert [T, ..n] to [T] (or similar, depending on the kind)
315 AutoUnsize(UnsizeKind<'tcx>),
317 /// Convert Box<[T, ..n]> to Box<[T]> or something similar in a Box.
318 /// With DST and Box a library type, this should be replaced by UnsizeStruct.
319 AutoUnsizeUniq(UnsizeKind<'tcx>),
321 /// Convert from T to *T
322 /// Value to thin pointer
323 /// The second field allows us to wrap other AutoRef adjustments.
324 AutoUnsafe(ast::Mutability, Option<Box<AutoRef<'tcx>>>),
327 // Ugly little helper function. The first bool in the returned tuple is true if
328 // there is an 'unsize to trait object' adjustment at the bottom of the
329 // adjustment. If that is surrounded by an AutoPtr, then we also return the
330 // region of the AutoPtr (in the third argument). The second bool is true if the
331 // adjustment is unique.
332 fn autoref_object_region(autoref: &AutoRef) -> (bool, bool, Option<Region>) {
333 fn unsize_kind_is_object(k: &UnsizeKind) -> bool {
335 &UnsizeVtable(..) => true,
336 &UnsizeStruct(box ref k, _) => unsize_kind_is_object(k),
342 &AutoUnsize(ref k) => (unsize_kind_is_object(k), false, None),
343 &AutoUnsizeUniq(ref k) => (unsize_kind_is_object(k), true, None),
344 &AutoPtr(adj_r, _, Some(box ref autoref)) => {
345 let (b, u, r) = autoref_object_region(autoref);
346 if r.is_some() || u {
352 &AutoUnsafe(_, Some(box ref autoref)) => autoref_object_region(autoref),
353 _ => (false, false, None)
357 // If the adjustment introduces a borrowed reference to a trait object, then
358 // returns the region of the borrowed reference.
359 pub fn adjusted_object_region(adj: &AutoAdjustment) -> Option<Region> {
361 &AdjustDerefRef(AutoDerefRef{autoref: Some(ref autoref), ..}) => {
362 let (b, _, r) = autoref_object_region(autoref);
373 // Returns true if there is a trait cast at the bottom of the adjustment.
374 pub fn adjust_is_object(adj: &AutoAdjustment) -> bool {
376 &AdjustDerefRef(AutoDerefRef{autoref: Some(ref autoref), ..}) => {
377 let (b, _, _) = autoref_object_region(autoref);
384 // If possible, returns the type expected from the given adjustment. This is not
385 // possible if the adjustment depends on the type of the adjusted expression.
386 pub fn type_of_adjust<'tcx>(cx: &ctxt<'tcx>, adj: &AutoAdjustment<'tcx>) -> Option<Ty<'tcx>> {
387 fn type_of_autoref<'tcx>(cx: &ctxt<'tcx>, autoref: &AutoRef<'tcx>) -> Option<Ty<'tcx>> {
389 &AutoUnsize(ref k) => match k {
390 &UnsizeVtable(TyTrait { ref principal, ref bounds }, _) => {
391 Some(mk_trait(cx, principal.clone(), bounds.clone()))
395 &AutoUnsizeUniq(ref k) => match k {
396 &UnsizeVtable(TyTrait { ref principal, ref bounds }, _) => {
397 Some(mk_uniq(cx, mk_trait(cx, principal.clone(), bounds.clone())))
401 &AutoPtr(r, m, Some(box ref autoref)) => {
402 match type_of_autoref(cx, autoref) {
403 Some(ty) => Some(mk_rptr(cx, cx.mk_region(r), mt {mutbl: m, ty: ty})),
407 &AutoUnsafe(m, Some(box ref autoref)) => {
408 match type_of_autoref(cx, autoref) {
409 Some(ty) => Some(mk_ptr(cx, mt {mutbl: m, ty: ty})),
418 &AdjustDerefRef(AutoDerefRef{autoref: Some(ref autoref), ..}) => {
419 type_of_autoref(cx, autoref)
425 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Show)]
426 pub struct param_index {
427 pub space: subst::ParamSpace,
431 #[derive(Clone, Show)]
432 pub enum MethodOrigin<'tcx> {
433 // fully statically resolved method
434 MethodStatic(ast::DefId),
436 // fully statically resolved unboxed closure invocation
437 MethodStaticUnboxedClosure(ast::DefId),
439 // method invoked on a type parameter with a bounded trait
440 MethodTypeParam(MethodParam<'tcx>),
442 // method invoked on a trait instance
443 MethodTraitObject(MethodObject<'tcx>),
447 // details for a method invoked with a receiver whose type is a type parameter
448 // with a bounded trait.
449 #[derive(Clone, Show)]
450 pub struct MethodParam<'tcx> {
451 // the precise trait reference that occurs as a bound -- this may
452 // be a supertrait of what the user actually typed. Note that it
453 // never contains bound regions; those regions should have been
454 // instantiated with fresh variables at this point.
455 pub trait_ref: Rc<ty::TraitRef<'tcx>>,
457 // index of uint in the list of methods for the trait
458 pub method_num: uint,
461 // details for a method invoked with a receiver whose type is an object
462 #[derive(Clone, Show)]
463 pub struct MethodObject<'tcx> {
464 // the (super)trait containing the method to be invoked
465 pub trait_ref: Rc<ty::TraitRef<'tcx>>,
467 // the actual base trait id of the object
468 pub object_trait_id: ast::DefId,
470 // index of the method to be invoked amongst the trait's methods
471 pub method_num: uint,
473 // index into the actual runtime vtable.
474 // the vtable is formed by concatenating together the method lists of
475 // the base object trait and all supertraits; this is the index into
477 pub real_index: uint,
481 pub struct MethodCallee<'tcx> {
482 pub origin: MethodOrigin<'tcx>,
484 pub substs: subst::Substs<'tcx>
487 /// With method calls, we store some extra information in
488 /// side tables (i.e method_map). We use
489 /// MethodCall as a key to index into these tables instead of
490 /// just directly using the expression's NodeId. The reason
491 /// for this being that we may apply adjustments (coercions)
492 /// with the resulting expression also needing to use the
493 /// side tables. The problem with this is that we don't
494 /// assign a separate NodeId to this new expression
495 /// and so it would clash with the base expression if both
496 /// needed to add to the side tables. Thus to disambiguate
497 /// we also keep track of whether there's an adjustment in
499 #[derive(Clone, Copy, PartialEq, Eq, Hash, Show)]
500 pub struct MethodCall {
501 pub expr_id: ast::NodeId,
502 pub adjustment: ExprAdjustment
505 #[derive(Clone, PartialEq, Eq, Hash, Show, RustcEncodable, RustcDecodable, Copy)]
506 pub enum ExprAdjustment {
513 pub fn expr(id: ast::NodeId) -> MethodCall {
516 adjustment: NoAdjustment
520 pub fn autoobject(id: ast::NodeId) -> MethodCall {
523 adjustment: AutoObject
527 pub fn autoderef(expr_id: ast::NodeId, autoderef: uint) -> MethodCall {
530 adjustment: AutoDeref(1 + autoderef)
535 // maps from an expression id that corresponds to a method call to the details
536 // of the method to be invoked
537 pub type MethodMap<'tcx> = RefCell<FnvHashMap<MethodCall, MethodCallee<'tcx>>>;
539 pub type vtable_param_res<'tcx> = Vec<vtable_origin<'tcx>>;
541 // Resolutions for bounds of all parameters, left to right, for a given path.
542 pub type vtable_res<'tcx> = VecPerParamSpace<vtable_param_res<'tcx>>;
545 pub enum vtable_origin<'tcx> {
547 Statically known vtable. def_id gives the impl item
548 from whence comes the vtable, and tys are the type substs.
549 vtable_res is the vtable itself.
551 vtable_static(ast::DefId, subst::Substs<'tcx>, vtable_res<'tcx>),
554 Dynamic vtable, comes from a parameter that has a bound on it:
555 fn foo<T:quux,baz,bar>(a: T) -- a's vtable would have a
558 The first argument is the param index (identifying T in the example),
559 and the second is the bound number (identifying baz)
561 vtable_param(param_index, uint),
564 Vtable automatically generated for an unboxed closure. The def ID is the
565 ID of the closure expression.
567 vtable_unboxed_closure(ast::DefId),
570 Asked to determine the vtable for ty_err. This is the value used
571 for the vtables of `Self` in a virtual call like `foo.bar()`
572 where `foo` is of object type. The same value is also used when
579 // For every explicit cast into an object type, maps from the cast
580 // expr to the associated trait ref.
581 pub type ObjectCastMap<'tcx> = RefCell<NodeMap<ty::PolyTraitRef<'tcx>>>;
583 /// A restriction that certain types must be the same size. The use of
584 /// `transmute` gives rise to these restrictions. These generally
585 /// cannot be checked until trans; therefore, each call to `transmute`
586 /// will push one or more such restriction into the
587 /// `transmute_restrictions` vector during `intrinsicck`. They are
588 /// then checked during `trans` by the fn `check_intrinsics`.
590 pub struct TransmuteRestriction<'tcx> {
591 /// The span whence the restriction comes.
594 /// The type being transmuted from.
595 pub original_from: Ty<'tcx>,
597 /// The type being transmuted to.
598 pub original_to: Ty<'tcx>,
600 /// The type being transmuted from, with all type parameters
601 /// substituted for an arbitrary representative. Not to be shown
603 pub substituted_from: Ty<'tcx>,
605 /// The type being transmuted to, with all type parameters
606 /// substituted for an arbitrary representative. Not to be shown
608 pub substituted_to: Ty<'tcx>,
610 /// NodeId of the transmute intrinsic.
615 pub struct CtxtArenas<'tcx> {
616 type_: TypedArena<TyS<'tcx>>,
617 substs: TypedArena<Substs<'tcx>>,
618 bare_fn: TypedArena<BareFnTy<'tcx>>,
619 region: TypedArena<Region>,
622 impl<'tcx> CtxtArenas<'tcx> {
623 pub fn new() -> CtxtArenas<'tcx> {
625 type_: TypedArena::new(),
626 substs: TypedArena::new(),
627 bare_fn: TypedArena::new(),
628 region: TypedArena::new(),
633 pub struct CommonTypes<'tcx> {
651 /// The data structure to keep track of all the information that typechecker
652 /// generates so that so that it can be reused and doesn't have to be redone
654 pub struct ctxt<'tcx> {
655 /// The arenas that types etc are allocated from.
656 arenas: &'tcx CtxtArenas<'tcx>,
658 /// Specifically use a speedy hash algorithm for this hash map, it's used
660 // FIXME(eddyb) use a FnvHashSet<InternedTy<'tcx>> when equivalent keys can
661 // queried from a HashSet.
662 interner: RefCell<FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>>,
664 // FIXME as above, use a hashset if equivalent elements can be queried.
665 substs_interner: RefCell<FnvHashMap<&'tcx Substs<'tcx>, &'tcx Substs<'tcx>>>,
666 bare_fn_interner: RefCell<FnvHashMap<&'tcx BareFnTy<'tcx>, &'tcx BareFnTy<'tcx>>>,
667 region_interner: RefCell<FnvHashMap<&'tcx Region, &'tcx Region>>,
669 /// Common types, pre-interned for your convenience.
670 pub types: CommonTypes<'tcx>,
675 pub named_region_map: resolve_lifetime::NamedRegionMap,
677 pub region_maps: middle::region::RegionMaps,
679 /// Stores the types for various nodes in the AST. Note that this table
680 /// is not guaranteed to be populated until after typeck. See
681 /// typeck::check::fn_ctxt for details.
682 pub node_types: RefCell<NodeMap<Ty<'tcx>>>,
684 /// Stores the type parameters which were substituted to obtain the type
685 /// of this node. This only applies to nodes that refer to entities
686 /// parameterized by type parameters, such as generic fns, types, or
688 pub item_substs: RefCell<NodeMap<ItemSubsts<'tcx>>>,
690 /// Maps from a trait item to the trait item "descriptor"
691 pub impl_or_trait_items: RefCell<DefIdMap<ImplOrTraitItem<'tcx>>>,
693 /// Maps from a trait def-id to a list of the def-ids of its trait items
694 pub trait_item_def_ids: RefCell<DefIdMap<Rc<Vec<ImplOrTraitItemId>>>>,
696 /// A cache for the trait_items() routine
697 pub trait_items_cache: RefCell<DefIdMap<Rc<Vec<ImplOrTraitItem<'tcx>>>>>,
699 pub impl_trait_cache: RefCell<DefIdMap<Option<Rc<ty::TraitRef<'tcx>>>>>,
701 pub trait_refs: RefCell<NodeMap<Rc<TraitRef<'tcx>>>>,
702 pub trait_defs: RefCell<DefIdMap<Rc<TraitDef<'tcx>>>>,
704 /// Maps from node-id of a trait object cast (like `foo as
705 /// Box<Trait>`) to the trait reference.
706 pub object_cast_map: ObjectCastMap<'tcx>,
708 pub map: ast_map::Map<'tcx>,
709 pub intrinsic_defs: RefCell<DefIdMap<Ty<'tcx>>>,
710 pub freevars: RefCell<FreevarMap>,
711 pub tcache: RefCell<DefIdMap<TypeScheme<'tcx>>>,
712 pub rcache: RefCell<FnvHashMap<creader_cache_key, Ty<'tcx>>>,
713 pub short_names_cache: RefCell<FnvHashMap<Ty<'tcx>, String>>,
714 pub tc_cache: RefCell<FnvHashMap<Ty<'tcx>, TypeContents>>,
715 pub ast_ty_to_ty_cache: RefCell<NodeMap<ast_ty_to_ty_cache_entry<'tcx>>>,
716 pub enum_var_cache: RefCell<DefIdMap<Rc<Vec<Rc<VariantInfo<'tcx>>>>>>,
717 pub ty_param_defs: RefCell<NodeMap<TypeParameterDef<'tcx>>>,
718 pub adjustments: RefCell<NodeMap<AutoAdjustment<'tcx>>>,
719 pub normalized_cache: RefCell<FnvHashMap<Ty<'tcx>, Ty<'tcx>>>,
720 pub lang_items: middle::lang_items::LanguageItems,
721 /// A mapping of fake provided method def_ids to the default implementation
722 pub provided_method_sources: RefCell<DefIdMap<ast::DefId>>,
723 pub struct_fields: RefCell<DefIdMap<Rc<Vec<field_ty>>>>,
725 /// Maps from def-id of a type or region parameter to its
726 /// (inferred) variance.
727 pub item_variance_map: RefCell<DefIdMap<Rc<ItemVariances>>>,
729 /// True if the variance has been computed yet; false otherwise.
730 pub variance_computed: Cell<bool>,
732 /// A mapping from the def ID of an enum or struct type to the def ID
733 /// of the method that implements its destructor. If the type is not
734 /// present in this map, it does not have a destructor. This map is
735 /// populated during the coherence phase of typechecking.
736 pub destructor_for_type: RefCell<DefIdMap<ast::DefId>>,
738 /// A method will be in this list if and only if it is a destructor.
739 pub destructors: RefCell<DefIdSet>,
741 /// Maps a trait onto a list of impls of that trait.
742 pub trait_impls: RefCell<DefIdMap<Rc<RefCell<Vec<ast::DefId>>>>>,
744 /// Maps a DefId of a type to a list of its inherent impls.
745 /// Contains implementations of methods that are inherent to a type.
746 /// Methods in these implementations don't need to be exported.
747 pub inherent_impls: RefCell<DefIdMap<Rc<Vec<ast::DefId>>>>,
749 /// Maps a DefId of an impl to a list of its items.
750 /// Note that this contains all of the impls that we know about,
751 /// including ones in other crates. It's not clear that this is the best
753 pub impl_items: RefCell<DefIdMap<Vec<ImplOrTraitItemId>>>,
755 /// Set of used unsafe nodes (functions or blocks). Unsafe nodes not
756 /// present in this set can be warned about.
757 pub used_unsafe: RefCell<NodeSet>,
759 /// Set of nodes which mark locals as mutable which end up getting used at
760 /// some point. Local variable definitions not in this set can be warned
762 pub used_mut_nodes: RefCell<NodeSet>,
764 /// The set of external nominal types whose implementations have been read.
765 /// This is used for lazy resolution of methods.
766 pub populated_external_types: RefCell<DefIdSet>,
768 /// The set of external traits whose implementations have been read. This
769 /// is used for lazy resolution of traits.
770 pub populated_external_traits: RefCell<DefIdSet>,
773 pub upvar_borrow_map: RefCell<UpvarBorrowMap>,
775 /// These two caches are used by const_eval when decoding external statics
776 /// and variants that are found.
777 pub extern_const_statics: RefCell<DefIdMap<ast::NodeId>>,
778 pub extern_const_variants: RefCell<DefIdMap<ast::NodeId>>,
780 pub method_map: MethodMap<'tcx>,
782 pub dependency_formats: RefCell<dependency_format::Dependencies>,
784 /// Records the type of each unboxed closure. The def ID is the ID of the
785 /// expression defining the unboxed closure.
786 pub unboxed_closures: RefCell<DefIdMap<UnboxedClosure<'tcx>>>,
788 pub node_lint_levels: RefCell<FnvHashMap<(ast::NodeId, lint::LintId),
791 /// The types that must be asserted to be the same size for `transmute`
792 /// to be valid. We gather up these restrictions in the intrinsicck pass
793 /// and check them in trans.
794 pub transmute_restrictions: RefCell<Vec<TransmuteRestriction<'tcx>>>,
796 /// Maps any item's def-id to its stability index.
797 pub stability: RefCell<stability::Index>,
799 /// Maps closures to their capture clauses.
800 pub capture_modes: RefCell<CaptureModeMap>,
802 /// Maps def IDs to true if and only if they're associated types.
803 pub associated_types: RefCell<DefIdMap<bool>>,
805 /// Caches the results of trait selection. This cache is used
806 /// for things that do not have to do with the parameters in scope.
807 pub selection_cache: traits::SelectionCache<'tcx>,
809 /// Caches the representation hints for struct definitions.
810 pub repr_hint_cache: RefCell<DefIdMap<Rc<Vec<attr::ReprAttr>>>>,
812 /// Caches whether types are known to impl Copy. Note that type
813 /// parameters are never placed into this cache, because their
814 /// results are dependent on the parameter environment.
815 pub type_impls_copy_cache: RefCell<HashMap<Ty<'tcx>,bool>>,
817 /// Caches whether types are known to impl Sized. Note that type
818 /// parameters are never placed into this cache, because their
819 /// results are dependent on the parameter environment.
820 pub type_impls_sized_cache: RefCell<HashMap<Ty<'tcx>,bool>>,
822 /// Caches whether traits are object safe
823 pub object_safety_cache: RefCell<DefIdMap<bool>>,
826 // Flags that we track on types. These flags are propagated upwards
827 // through the type during type construction, so that we can quickly
828 // check whether the type has various kinds of types in it without
829 // recursing over the type itself.
831 flags TypeFlags: u32 {
832 const NO_TYPE_FLAGS = 0b0,
833 const HAS_PARAMS = 0b1,
834 const HAS_SELF = 0b10,
835 const HAS_TY_INFER = 0b100,
836 const HAS_RE_INFER = 0b1000,
837 const HAS_RE_LATE_BOUND = 0b10000,
838 const HAS_REGIONS = 0b100000,
839 const HAS_TY_ERR = 0b1000000,
840 const HAS_PROJECTION = 0b10000000,
841 const NEEDS_SUBST = HAS_PARAMS.bits | HAS_SELF.bits | HAS_REGIONS.bits,
845 macro_rules! sty_debug_print {
846 ($ctxt: expr, $($variant: ident),*) => {{
847 // curious inner module to allow variant names to be used as
859 pub fn go(tcx: &ty::ctxt) {
860 let mut total = DebugStat {
862 region_infer: 0, ty_infer: 0, both_infer: 0,
864 $(let mut $variant = total;)*
867 for (_, t) in tcx.interner.borrow().iter() {
868 let variant = match t.sty {
869 ty::ty_bool | ty::ty_char | ty::ty_int(..) | ty::ty_uint(..) |
870 ty::ty_float(..) | ty::ty_str => continue,
871 ty::ty_err => /* unimportant */ continue,
872 $(ty::$variant(..) => &mut $variant,)*
874 let region = t.flags.intersects(ty::HAS_RE_INFER);
875 let ty = t.flags.intersects(ty::HAS_TY_INFER);
879 if region { total.region_infer += 1; variant.region_infer += 1 }
880 if ty { total.ty_infer += 1; variant.ty_infer += 1 }
881 if region && ty { total.both_infer += 1; variant.both_infer += 1 }
883 println!("Ty interner total ty region both");
884 $(println!(" {:18}: {uses:6} {usespc:4.1}%, \
885 {ty:4.1}% {region:5.1}% {both:4.1}%",
886 stringify!($variant),
887 uses = $variant.total,
888 usespc = $variant.total as f64 * 100.0 / total.total as f64,
889 ty = $variant.ty_infer as f64 * 100.0 / total.total as f64,
890 region = $variant.region_infer as f64 * 100.0 / total.total as f64,
891 both = $variant.both_infer as f64 * 100.0 / total.total as f64);
893 println!(" total {uses:6} \
894 {ty:4.1}% {region:5.1}% {both:4.1}%",
896 ty = total.ty_infer as f64 * 100.0 / total.total as f64,
897 region = total.region_infer as f64 * 100.0 / total.total as f64,
898 both = total.both_infer as f64 * 100.0 / total.total as f64)
906 impl<'tcx> ctxt<'tcx> {
907 pub fn print_debug_stats(&self) {
910 ty_enum, ty_uniq, ty_vec, ty_ptr, ty_rptr, ty_bare_fn, ty_trait,
911 ty_struct, ty_unboxed_closure, ty_tup, ty_param, ty_open, ty_infer, ty_projection);
913 println!("Substs interner: #{}", self.substs_interner.borrow().len());
914 println!("BareFnTy interner: #{}", self.bare_fn_interner.borrow().len());
915 println!("Region interner: #{}", self.region_interner.borrow().len());
920 pub struct TyS<'tcx> {
922 pub flags: TypeFlags,
924 // the maximal depth of any bound regions appearing in this type.
928 impl fmt::Show for TypeFlags {
929 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
930 write!(f, "{}", self.bits)
934 impl<'tcx> PartialEq for TyS<'tcx> {
935 fn eq(&self, other: &TyS<'tcx>) -> bool {
936 (self as *const _) == (other as *const _)
939 impl<'tcx> Eq for TyS<'tcx> {}
941 impl<'tcx, S: Writer + Hasher> Hash<S> for TyS<'tcx> {
942 fn hash(&self, s: &mut S) {
943 (self as *const _).hash(s)
947 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
949 /// An entry in the type interner.
950 pub struct InternedTy<'tcx> {
954 // NB: An InternedTy compares and hashes as a sty.
955 impl<'tcx> PartialEq for InternedTy<'tcx> {
956 fn eq(&self, other: &InternedTy<'tcx>) -> bool {
957 self.ty.sty == other.ty.sty
961 impl<'tcx> Eq for InternedTy<'tcx> {}
963 impl<'tcx, S: Writer + Hasher> Hash<S> for InternedTy<'tcx> {
964 fn hash(&self, s: &mut S) {
969 impl<'tcx> BorrowFrom<InternedTy<'tcx>> for sty<'tcx> {
970 fn borrow_from<'a>(ty: &'a InternedTy<'tcx>) -> &'a sty<'tcx> {
975 pub fn type_has_params(ty: Ty) -> bool {
976 ty.flags.intersects(HAS_PARAMS)
978 pub fn type_has_self(ty: Ty) -> bool {
979 ty.flags.intersects(HAS_SELF)
981 pub fn type_has_ty_infer(ty: Ty) -> bool {
982 ty.flags.intersects(HAS_TY_INFER)
984 pub fn type_needs_infer(ty: Ty) -> bool {
985 ty.flags.intersects(HAS_TY_INFER | HAS_RE_INFER)
987 pub fn type_has_projection(ty: Ty) -> bool {
988 ty.flags.intersects(HAS_PROJECTION)
991 pub fn type_has_late_bound_regions(ty: Ty) -> bool {
992 ty.flags.intersects(HAS_RE_LATE_BOUND)
995 /// An "escaping region" is a bound region whose binder is not part of `t`.
997 /// So, for example, consider a type like the following, which has two binders:
999 /// for<'a> fn(x: for<'b> fn(&'a int, &'b int))
1000 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ outer scope
1001 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ inner scope
1003 /// This type has *bound regions* (`'a`, `'b`), but it does not have escaping regions, because the
1004 /// binders of both `'a` and `'b` are part of the type itself. However, if we consider the *inner
1005 /// fn type*, that type has an escaping region: `'a`.
1007 /// Note that what I'm calling an "escaping region" is often just called a "free region". However,
1008 /// we already use the term "free region". It refers to the regions that we use to represent bound
1009 /// regions on a fn definition while we are typechecking its body.
1011 /// To clarify, conceptually there is no particular difference between an "escaping" region and a
1012 /// "free" region. However, there is a big difference in practice. Basically, when "entering" a
1013 /// binding level, one is generally required to do some sort of processing to a bound region, such
1014 /// as replacing it with a fresh/skolemized region, or making an entry in the environment to
1015 /// represent the scope to which it is attached, etc. An escaping region represents a bound region
1016 /// for which this processing has not yet been done.
1017 pub fn type_has_escaping_regions(ty: Ty) -> bool {
1018 type_escapes_depth(ty, 0)
1021 pub fn type_escapes_depth(ty: Ty, depth: u32) -> bool {
1022 ty.region_depth > depth
1025 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1026 pub struct BareFnTy<'tcx> {
1027 pub unsafety: ast::Unsafety,
1029 pub sig: PolyFnSig<'tcx>,
1032 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1033 pub struct ClosureTy<'tcx> {
1034 pub unsafety: ast::Unsafety,
1035 pub onceness: ast::Onceness,
1036 pub bounds: ExistentialBounds<'tcx>,
1037 pub sig: PolyFnSig<'tcx>,
1041 #[derive(Clone, Copy, PartialEq, Eq, Hash, Show)]
1042 pub enum FnOutput<'tcx> {
1043 FnConverging(Ty<'tcx>),
1047 impl<'tcx> FnOutput<'tcx> {
1048 pub fn diverges(&self) -> bool {
1049 *self == FnDiverging
1052 pub fn unwrap(self) -> Ty<'tcx> {
1054 ty::FnConverging(t) => t,
1055 ty::FnDiverging => unreachable!()
1060 pub type PolyFnOutput<'tcx> = Binder<FnOutput<'tcx>>;
1062 impl<'tcx> PolyFnOutput<'tcx> {
1063 pub fn diverges(&self) -> bool {
1068 /// Signature of a function type, which I have arbitrarily
1069 /// decided to use to refer to the input/output types.
1071 /// - `inputs` is the list of arguments and their modes.
1072 /// - `output` is the return type.
1073 /// - `variadic` indicates whether this is a variadic function. (only true for foreign fns)
1074 #[derive(Clone, PartialEq, Eq, Hash)]
1075 pub struct FnSig<'tcx> {
1076 pub inputs: Vec<Ty<'tcx>>,
1077 pub output: FnOutput<'tcx>,
1081 pub type PolyFnSig<'tcx> = Binder<FnSig<'tcx>>;
1083 impl<'tcx> PolyFnSig<'tcx> {
1084 pub fn inputs(&self) -> ty::Binder<Vec<Ty<'tcx>>> {
1085 ty::Binder(self.0.inputs.clone())
1087 pub fn input(&self, index: uint) -> ty::Binder<Ty<'tcx>> {
1088 ty::Binder(self.0.inputs[index])
1090 pub fn output(&self) -> ty::Binder<FnOutput<'tcx>> {
1091 ty::Binder(self.0.output.clone())
1093 pub fn variadic(&self) -> bool {
1098 #[derive(Clone, Copy, PartialEq, Eq, Hash, Show)]
1099 pub struct ParamTy {
1100 pub space: subst::ParamSpace,
1102 pub name: ast::Name,
1105 /// A [De Bruijn index][dbi] is a standard means of representing
1106 /// regions (and perhaps later types) in a higher-ranked setting. In
1107 /// particular, imagine a type like this:
1109 /// for<'a> fn(for<'b> fn(&'b int, &'a int), &'a char)
1112 /// | +------------+ 1 | |
1114 /// +--------------------------------+ 2 |
1116 /// +------------------------------------------+ 1
1118 /// In this type, there are two binders (the outer fn and the inner
1119 /// fn). We need to be able to determine, for any given region, which
1120 /// fn type it is bound by, the inner or the outer one. There are
1121 /// various ways you can do this, but a De Bruijn index is one of the
1122 /// more convenient and has some nice properties. The basic idea is to
1123 /// count the number of binders, inside out. Some examples should help
1124 /// clarify what I mean.
1126 /// Let's start with the reference type `&'b int` that is the first
1127 /// argument to the inner function. This region `'b` is assigned a De
1128 /// Bruijn index of 1, meaning "the innermost binder" (in this case, a
1129 /// fn). The region `'a` that appears in the second argument type (`&'a
1130 /// int`) would then be assigned a De Bruijn index of 2, meaning "the
1131 /// second-innermost binder". (These indices are written on the arrays
1132 /// in the diagram).
1134 /// What is interesting is that De Bruijn index attached to a particular
1135 /// variable will vary depending on where it appears. For example,
1136 /// the final type `&'a char` also refers to the region `'a` declared on
1137 /// the outermost fn. But this time, this reference is not nested within
1138 /// any other binders (i.e., it is not an argument to the inner fn, but
1139 /// rather the outer one). Therefore, in this case, it is assigned a
1140 /// De Bruijn index of 1, because the innermost binder in that location
1141 /// is the outer fn.
1143 /// [dbi]: http://en.wikipedia.org/wiki/De_Bruijn_index
1144 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Show, Copy)]
1145 pub struct DebruijnIndex {
1146 // We maintain the invariant that this is never 0. So 1 indicates
1147 // the innermost binder. To ensure this, create with `DebruijnIndex::new`.
1151 /// Representation of regions:
1152 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Show, Copy)]
1154 // Region bound in a type or fn declaration which will be
1155 // substituted 'early' -- that is, at the same time when type
1156 // parameters are substituted.
1157 ReEarlyBound(/* param id */ ast::NodeId,
1162 // Region bound in a function scope, which will be substituted when the
1163 // function is called.
1164 ReLateBound(DebruijnIndex, BoundRegion),
1166 /// When checking a function body, the types of all arguments and so forth
1167 /// that refer to bound region parameters are modified to refer to free
1168 /// region parameters.
1171 /// A concrete region naming some expression within the current function.
1172 ReScope(region::CodeExtent),
1174 /// Static data that has an "infinite" lifetime. Top in the region lattice.
1177 /// A region variable. Should not exist after typeck.
1178 ReInfer(InferRegion),
1180 /// Empty lifetime is for data that is never accessed.
1181 /// Bottom in the region lattice. We treat ReEmpty somewhat
1182 /// specially; at least right now, we do not generate instances of
1183 /// it during the GLB computations, but rather
1184 /// generate an error instead. This is to improve error messages.
1185 /// The only way to get an instance of ReEmpty is to have a region
1186 /// variable with no constraints.
1190 /// Upvars do not get their own node-id. Instead, we use the pair of
1191 /// the original var id (that is, the root variable that is referenced
1192 /// by the upvar) and the id of the closure expression.
1193 #[derive(Clone, Copy, PartialEq, Eq, Hash, Show)]
1194 pub struct UpvarId {
1195 pub var_id: ast::NodeId,
1196 pub closure_expr_id: ast::NodeId,
1199 #[derive(Clone, PartialEq, Eq, Hash, Show, RustcEncodable, RustcDecodable, Copy)]
1200 pub enum BorrowKind {
1201 /// Data must be immutable and is aliasable.
1204 /// Data must be immutable but not aliasable. This kind of borrow
1205 /// cannot currently be expressed by the user and is used only in
1206 /// implicit closure bindings. It is needed when you the closure
1207 /// is borrowing or mutating a mutable referent, e.g.:
1209 /// let x: &mut int = ...;
1210 /// let y = || *x += 5;
1212 /// If we were to try to translate this closure into a more explicit
1213 /// form, we'd encounter an error with the code as written:
1215 /// struct Env { x: & &mut int }
1216 /// let x: &mut int = ...;
1217 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
1218 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
1220 /// This is then illegal because you cannot mutate a `&mut` found
1221 /// in an aliasable location. To solve, you'd have to translate with
1222 /// an `&mut` borrow:
1224 /// struct Env { x: & &mut int }
1225 /// let x: &mut int = ...;
1226 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
1227 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
1229 /// Now the assignment to `**env.x` is legal, but creating a
1230 /// mutable pointer to `x` is not because `x` is not mutable. We
1231 /// could fix this by declaring `x` as `let mut x`. This is ok in
1232 /// user code, if awkward, but extra weird for closures, since the
1233 /// borrow is hidden.
1235 /// So we introduce a "unique imm" borrow -- the referent is
1236 /// immutable, but not aliasable. This solves the problem. For
1237 /// simplicity, we don't give users the way to express this
1238 /// borrow, it's just used when translating closures.
1241 /// Data is mutable and not aliasable.
1245 /// Information describing the borrowing of an upvar. This is computed
1246 /// during `typeck`, specifically by `regionck`. The general idea is
1247 /// that the compiler analyses treat closures like:
1249 /// let closure: &'e fn() = || {
1250 /// x = 1; // upvar x is assigned to
1251 /// use(y); // upvar y is read
1252 /// foo(&z); // upvar z is borrowed immutably
1255 /// as if they were "desugared" to something loosely like:
1257 /// struct Vars<'x,'y,'z> { x: &'x mut int,
1258 /// y: &'y const int,
1260 /// let closure: &'e fn() = {
1261 /// fn f(env: &Vars) {
1266 /// let env: &'e mut Vars<'x,'y,'z> = &mut Vars { x: &'x mut x,
1272 /// This is basically what happens at runtime. The closure is basically
1273 /// an existentially quantified version of the `(env, f)` pair.
1275 /// This data structure indicates the region and mutability of a single
1276 /// one of the `x...z` borrows.
1278 /// It may not be obvious why each borrowed variable gets its own
1279 /// lifetime (in the desugared version of the example, these are indicated
1280 /// by the lifetime parameters `'x`, `'y`, and `'z` in the `Vars` definition).
1281 /// Each such lifetime must encompass the lifetime `'e` of the closure itself,
1282 /// but need not be identical to it. The reason that this makes sense:
1284 /// - Callers are only permitted to invoke the closure, and hence to
1285 /// use the pointers, within the lifetime `'e`, so clearly `'e` must
1286 /// be a sublifetime of `'x...'z`.
1287 /// - The closure creator knows which upvars were borrowed by the closure
1288 /// and thus `x...z` will be reserved for `'x...'z` respectively.
1289 /// - Through mutation, the borrowed upvars can actually escape
1290 /// the closure, so sometimes it is necessary for them to be larger
1291 /// than the closure lifetime itself.
1292 #[derive(PartialEq, Clone, RustcEncodable, RustcDecodable, Show, Copy)]
1293 pub struct UpvarBorrow {
1294 pub kind: BorrowKind,
1295 pub region: ty::Region,
1298 pub type UpvarBorrowMap = FnvHashMap<UpvarId, UpvarBorrow>;
1301 pub fn is_bound(&self) -> bool {
1303 ty::ReEarlyBound(..) => true,
1304 ty::ReLateBound(..) => true,
1309 pub fn escapes_depth(&self, depth: u32) -> bool {
1311 ty::ReLateBound(debruijn, _) => debruijn.depth > depth,
1317 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash,
1318 RustcEncodable, RustcDecodable, Show, Copy)]
1319 /// A "free" region `fr` can be interpreted as "some region
1320 /// at least as big as the scope `fr.scope`".
1321 pub struct FreeRegion {
1322 pub scope: region::CodeExtent,
1323 pub bound_region: BoundRegion
1326 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash,
1327 RustcEncodable, RustcDecodable, Show, Copy)]
1328 pub enum BoundRegion {
1329 /// An anonymous region parameter for a given fn (&T)
1332 /// Named region parameters for functions (a in &'a T)
1334 /// The def-id is needed to distinguish free regions in
1335 /// the event of shadowing.
1336 BrNamed(ast::DefId, ast::Name),
1338 /// Fresh bound identifiers created during GLB computations.
1341 // Anonymous region for the implicit env pointer parameter
1346 // NB: If you change this, you'll probably want to change the corresponding
1347 // AST structure in libsyntax/ast.rs as well.
1348 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1349 pub enum sty<'tcx> {
1353 ty_uint(ast::UintTy),
1354 ty_float(ast::FloatTy),
1355 /// Substs here, possibly against intuition, *may* contain `ty_param`s.
1356 /// That is, even after substitution it is possible that there are type
1357 /// variables. This happens when the `ty_enum` corresponds to an enum
1358 /// definition and not a concrete use of it. To get the correct `ty_enum`
1359 /// from the tcx, use the `NodeId` from the `ast::Ty` and look it up in
1360 /// the `ast_ty_to_ty_cache`. This is probably true for `ty_struct` as
1362 ty_enum(DefId, &'tcx Substs<'tcx>),
1365 ty_vec(Ty<'tcx>, Option<uint>), // Second field is length.
1367 ty_rptr(&'tcx Region, mt<'tcx>),
1369 // If the def-id is Some(_), then this is the type of a specific
1370 // fn item. Otherwise, if None(_), it a fn pointer type.
1371 ty_bare_fn(Option<DefId>, &'tcx BareFnTy<'tcx>),
1373 ty_trait(Box<TyTrait<'tcx>>),
1374 ty_struct(DefId, &'tcx Substs<'tcx>),
1376 ty_unboxed_closure(DefId, &'tcx Region, &'tcx Substs<'tcx>),
1378 ty_tup(Vec<Ty<'tcx>>),
1380 ty_projection(ProjectionTy<'tcx>),
1381 ty_param(ParamTy), // type parameter
1383 ty_open(Ty<'tcx>), // A deref'ed fat pointer, i.e., a dynamically sized value
1384 // and its size. Only ever used in trans. It is not necessary
1385 // earlier since we don't need to distinguish a DST with its
1386 // size (e.g., in a deref) vs a DST with the size elsewhere (
1387 // e.g., in a field).
1389 ty_infer(InferTy), // something used only during inference/typeck
1390 ty_err, // Also only used during inference/typeck, to represent
1391 // the type of an erroneous expression (helps cut down
1392 // on non-useful type error messages)
1395 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1396 pub struct TyTrait<'tcx> {
1397 pub principal: ty::PolyTraitRef<'tcx>,
1398 pub bounds: ExistentialBounds<'tcx>,
1401 impl<'tcx> TyTrait<'tcx> {
1402 pub fn principal_def_id(&self) -> ast::DefId {
1403 self.principal.0.def_id
1406 /// Object types don't have a self-type specified. Therefore, when
1407 /// we convert the principal trait-ref into a normal trait-ref,
1408 /// you must give *some* self-type. A common choice is `mk_err()`
1409 /// or some skolemized type.
1410 pub fn principal_trait_ref_with_self_ty(&self,
1413 -> ty::PolyTraitRef<'tcx>
1415 // otherwise the escaping regions would be captured by the binder
1416 assert!(!self_ty.has_escaping_regions());
1418 ty::Binder(Rc::new(ty::TraitRef {
1419 def_id: self.principal.0.def_id,
1420 substs: tcx.mk_substs(self.principal.0.substs.with_self_ty(self_ty)),
1424 pub fn projection_bounds_with_self_ty(&self,
1427 -> Vec<ty::PolyProjectionPredicate<'tcx>>
1429 // otherwise the escaping regions would be captured by the binders
1430 assert!(!self_ty.has_escaping_regions());
1432 self.bounds.projection_bounds.iter()
1433 .map(|in_poly_projection_predicate| {
1434 let in_projection_ty = &in_poly_projection_predicate.0.projection_ty;
1435 let substs = tcx.mk_substs(in_projection_ty.trait_ref.substs.with_self_ty(self_ty));
1437 Rc::new(ty::TraitRef::new(in_projection_ty.trait_ref.def_id,
1439 let projection_ty = ty::ProjectionTy {
1440 trait_ref: trait_ref,
1441 item_name: in_projection_ty.item_name
1443 ty::Binder(ty::ProjectionPredicate {
1444 projection_ty: projection_ty,
1445 ty: in_poly_projection_predicate.0.ty
1452 /// A complete reference to a trait. These take numerous guises in syntax,
1453 /// but perhaps the most recognizable form is in a where clause:
1457 /// This would be represented by a trait-reference where the def-id is the
1458 /// def-id for the trait `Foo` and the substs defines `T` as parameter 0 in the
1459 /// `SelfSpace` and `U` as parameter 0 in the `TypeSpace`.
1461 /// Trait references also appear in object types like `Foo<U>`, but in
1462 /// that case the `Self` parameter is absent from the substitutions.
1464 /// Note that a `TraitRef` introduces a level of region binding, to
1465 /// account for higher-ranked trait bounds like `T : for<'a> Foo<&'a
1466 /// U>` or higher-ranked object types.
1467 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1468 pub struct TraitRef<'tcx> {
1470 pub substs: &'tcx Substs<'tcx>,
1473 pub type PolyTraitRef<'tcx> = Binder<Rc<TraitRef<'tcx>>>;
1475 impl<'tcx> PolyTraitRef<'tcx> {
1476 pub fn self_ty(&self) -> Ty<'tcx> {
1480 pub fn def_id(&self) -> ast::DefId {
1484 pub fn substs(&self) -> &'tcx Substs<'tcx> {
1485 // FIXME(#20664) every use of this fn is probably a bug, it should yield Binder<>
1489 pub fn input_types(&self) -> &[Ty<'tcx>] {
1490 // FIXME(#20664) every use of this fn is probably a bug, it should yield Binder<>
1491 self.0.input_types()
1494 pub fn to_poly_trait_predicate(&self) -> PolyTraitPredicate<'tcx> {
1495 // Note that we preserve binding levels
1496 Binder(TraitPredicate { trait_ref: self.0.clone() })
1500 /// Binder is a binder for higher-ranked lifetimes. It is part of the
1501 /// compiler's representation for things like `for<'a> Fn(&'a int)`
1502 /// (which would be represented by the type `PolyTraitRef ==
1503 /// Binder<TraitRef>`). Note that when we skolemize, instantiate,
1504 /// erase, or otherwise "discharge" these bound reons, we change the
1505 /// type from `Binder<T>` to just `T` (see
1506 /// e.g. `liberate_late_bound_regions`).
1507 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1508 pub struct Binder<T>(pub T);
1510 #[derive(Clone, Copy, PartialEq)]
1511 pub enum IntVarValue {
1512 IntType(ast::IntTy),
1513 UintType(ast::UintTy),
1516 #[derive(Clone, Copy, Show)]
1517 pub enum terr_vstore_kind {
1524 #[derive(Clone, Copy, Show)]
1525 pub struct expected_found<T> {
1530 // Data structures used in type unification
1531 #[derive(Clone, Copy, Show)]
1532 pub enum type_err<'tcx> {
1534 terr_unsafety_mismatch(expected_found<ast::Unsafety>),
1535 terr_onceness_mismatch(expected_found<Onceness>),
1536 terr_abi_mismatch(expected_found<abi::Abi>),
1538 terr_box_mutability,
1539 terr_ptr_mutability,
1540 terr_ref_mutability,
1541 terr_vec_mutability,
1542 terr_tuple_size(expected_found<uint>),
1543 terr_fixed_array_size(expected_found<uint>),
1544 terr_ty_param_size(expected_found<uint>),
1546 terr_regions_does_not_outlive(Region, Region),
1547 terr_regions_not_same(Region, Region),
1548 terr_regions_no_overlap(Region, Region),
1549 terr_regions_insufficiently_polymorphic(BoundRegion, Region),
1550 terr_regions_overly_polymorphic(BoundRegion, Region),
1551 terr_sorts(expected_found<Ty<'tcx>>),
1552 terr_integer_as_char,
1553 terr_int_mismatch(expected_found<IntVarValue>),
1554 terr_float_mismatch(expected_found<ast::FloatTy>),
1555 terr_traits(expected_found<ast::DefId>),
1556 terr_builtin_bounds(expected_found<BuiltinBounds>),
1557 terr_variadic_mismatch(expected_found<bool>),
1559 terr_convergence_mismatch(expected_found<bool>),
1560 terr_projection_name_mismatched(expected_found<ast::Name>),
1561 terr_projection_bounds_length(expected_found<uint>),
1564 /// Bounds suitable for a named type parameter like `A` in `fn foo<A>`
1565 /// as well as the existential type parameter in an object type.
1566 #[derive(PartialEq, Eq, Hash, Clone, Show)]
1567 pub struct ParamBounds<'tcx> {
1568 pub region_bounds: Vec<ty::Region>,
1569 pub builtin_bounds: BuiltinBounds,
1570 pub trait_bounds: Vec<PolyTraitRef<'tcx>>,
1571 pub projection_bounds: Vec<PolyProjectionPredicate<'tcx>>,
1574 /// Bounds suitable for an existentially quantified type parameter
1575 /// such as those that appear in object types or closure types. The
1576 /// major difference between this case and `ParamBounds` is that
1577 /// general purpose trait bounds are omitted and there must be
1578 /// *exactly one* region.
1579 #[derive(PartialEq, Eq, Hash, Clone, Show)]
1580 pub struct ExistentialBounds<'tcx> {
1581 pub region_bound: ty::Region,
1582 pub builtin_bounds: BuiltinBounds,
1583 pub projection_bounds: Vec<PolyProjectionPredicate<'tcx>>,
1586 pub type BuiltinBounds = EnumSet<BuiltinBound>;
1588 #[derive(Clone, RustcEncodable, PartialEq, Eq, RustcDecodable, Hash,
1591 pub enum BuiltinBound {
1598 pub fn empty_builtin_bounds() -> BuiltinBounds {
1602 pub fn all_builtin_bounds() -> BuiltinBounds {
1603 let mut set = EnumSet::new();
1604 set.insert(BoundSend);
1605 set.insert(BoundSized);
1606 set.insert(BoundSync);
1610 /// An existential bound that does not implement any traits.
1611 pub fn region_existential_bound<'tcx>(r: ty::Region) -> ExistentialBounds<'tcx> {
1612 ty::ExistentialBounds { region_bound: r,
1613 builtin_bounds: empty_builtin_bounds(),
1614 projection_bounds: Vec::new() }
1617 impl CLike for BuiltinBound {
1618 fn to_uint(&self) -> uint {
1621 fn from_uint(v: uint) -> BuiltinBound {
1622 unsafe { mem::transmute(v) }
1626 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1631 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1636 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1637 pub struct FloatVid {
1641 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
1642 pub struct RegionVid {
1646 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1652 /// A `FreshTy` is one that is generated as a replacement for an
1653 /// unbound type variable. This is convenient for caching etc. See
1654 /// `middle::infer::freshen` for more details.
1657 // FIXME -- once integral fallback is impl'd, we should remove
1658 // this type. It's only needed to prevent spurious errors for
1659 // integers whose type winds up never being constrained.
1663 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Show, Copy)]
1664 pub enum UnconstrainedNumeric {
1671 #[derive(Clone, RustcEncodable, RustcDecodable, Eq, Hash, Show, Copy)]
1672 pub enum InferRegion {
1674 ReSkolemized(u32, BoundRegion)
1677 impl cmp::PartialEq for InferRegion {
1678 fn eq(&self, other: &InferRegion) -> bool {
1679 match ((*self), *other) {
1680 (ReVar(rva), ReVar(rvb)) => {
1683 (ReSkolemized(rva, _), ReSkolemized(rvb, _)) => {
1689 fn ne(&self, other: &InferRegion) -> bool {
1690 !((*self) == (*other))
1694 impl fmt::Show for TyVid {
1695 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result{
1696 write!(f, "_#{}t", self.index)
1700 impl fmt::Show for IntVid {
1701 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1702 write!(f, "_#{}i", self.index)
1706 impl fmt::Show for FloatVid {
1707 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1708 write!(f, "_#{}f", self.index)
1712 impl fmt::Show for RegionVid {
1713 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1714 write!(f, "'_#{}r", self.index)
1718 impl<'tcx> fmt::Show for FnSig<'tcx> {
1719 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1720 write!(f, "({:?}; variadic: {})->{:?}", self.inputs, self.variadic, self.output)
1724 impl fmt::Show for InferTy {
1725 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1727 TyVar(ref v) => v.fmt(f),
1728 IntVar(ref v) => v.fmt(f),
1729 FloatVar(ref v) => v.fmt(f),
1730 FreshTy(v) => write!(f, "FreshTy({:?})", v),
1731 FreshIntTy(v) => write!(f, "FreshIntTy({:?})", v),
1736 impl fmt::Show for IntVarValue {
1737 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1739 IntType(ref v) => v.fmt(f),
1740 UintType(ref v) => v.fmt(f),
1745 #[derive(Clone, Show)]
1746 pub struct TypeParameterDef<'tcx> {
1747 pub name: ast::Name,
1748 pub def_id: ast::DefId,
1749 pub space: subst::ParamSpace,
1751 pub bounds: ParamBounds<'tcx>,
1752 pub default: Option<Ty<'tcx>>,
1755 #[derive(RustcEncodable, RustcDecodable, Clone, Show)]
1756 pub struct RegionParameterDef {
1757 pub name: ast::Name,
1758 pub def_id: ast::DefId,
1759 pub space: subst::ParamSpace,
1761 pub bounds: Vec<ty::Region>,
1764 impl RegionParameterDef {
1765 pub fn to_early_bound_region(&self) -> ty::Region {
1766 ty::ReEarlyBound(self.def_id.node, self.space, self.index, self.name)
1770 /// Information about the formal type/lifetime parameters associated
1771 /// with an item or method. Analogous to ast::Generics.
1772 #[derive(Clone, Show)]
1773 pub struct Generics<'tcx> {
1774 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
1775 pub regions: VecPerParamSpace<RegionParameterDef>,
1776 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1779 impl<'tcx> Generics<'tcx> {
1780 pub fn empty() -> Generics<'tcx> {
1782 types: VecPerParamSpace::empty(),
1783 regions: VecPerParamSpace::empty(),
1784 predicates: VecPerParamSpace::empty(),
1788 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
1789 !self.types.is_empty_in(space)
1792 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
1793 !self.regions.is_empty_in(space)
1796 pub fn is_empty(&self) -> bool {
1797 self.types.is_empty() && self.regions.is_empty()
1800 pub fn to_bounds(&self, tcx: &ty::ctxt<'tcx>, substs: &Substs<'tcx>)
1801 -> GenericBounds<'tcx> {
1803 predicates: self.predicates.subst(tcx, substs),
1808 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1809 pub enum Predicate<'tcx> {
1810 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
1811 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1812 /// would be the parameters in the `TypeSpace`.
1813 Trait(PolyTraitPredicate<'tcx>),
1815 /// where `T1 == T2`.
1816 Equate(PolyEquatePredicate<'tcx>),
1819 RegionOutlives(PolyRegionOutlivesPredicate),
1822 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1824 /// where <T as TraitRef>::Name == X, approximately.
1825 /// See `ProjectionPredicate` struct for details.
1826 Projection(PolyProjectionPredicate<'tcx>),
1829 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1830 pub struct TraitPredicate<'tcx> {
1831 pub trait_ref: Rc<TraitRef<'tcx>>
1833 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1835 impl<'tcx> TraitPredicate<'tcx> {
1836 pub fn def_id(&self) -> ast::DefId {
1837 self.trait_ref.def_id
1840 pub fn input_types(&self) -> &[Ty<'tcx>] {
1841 self.trait_ref.substs.types.as_slice()
1844 pub fn self_ty(&self) -> Ty<'tcx> {
1845 self.trait_ref.self_ty()
1849 impl<'tcx> PolyTraitPredicate<'tcx> {
1850 pub fn def_id(&self) -> ast::DefId {
1855 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1856 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
1857 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
1859 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1860 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1861 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1862 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
1863 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
1865 /// This kind of predicate has no *direct* correspondent in the
1866 /// syntax, but it roughly corresponds to the syntactic forms:
1868 /// 1. `T : TraitRef<..., Item=Type>`
1869 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1871 /// In particular, form #1 is "desugared" to the combination of a
1872 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1873 /// predicates. Form #2 is a broader form in that it also permits
1874 /// equality between arbitrary types. Processing an instance of Form
1875 /// #2 eventually yields one of these `ProjectionPredicate`
1876 /// instances to normalize the LHS.
1877 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1878 pub struct ProjectionPredicate<'tcx> {
1879 pub projection_ty: ProjectionTy<'tcx>,
1883 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1885 impl<'tcx> PolyProjectionPredicate<'tcx> {
1886 pub fn item_name(&self) -> ast::Name {
1887 self.0.projection_ty.item_name // safe to skip the binder to access a name
1890 pub fn sort_key(&self) -> (ast::DefId, ast::Name) {
1891 self.0.projection_ty.sort_key()
1895 /// Represents the projection of an associated type. In explicit UFCS
1896 /// form this would be written `<T as Trait<..>>::N`.
1897 #[derive(Clone, PartialEq, Eq, Hash, Show)]
1898 pub struct ProjectionTy<'tcx> {
1899 /// The trait reference `T as Trait<..>`.
1900 pub trait_ref: Rc<ty::TraitRef<'tcx>>,
1902 /// The name `N` of the associated type.
1903 pub item_name: ast::Name,
1906 impl<'tcx> ProjectionTy<'tcx> {
1907 pub fn sort_key(&self) -> (ast::DefId, ast::Name) {
1908 (self.trait_ref.def_id, self.item_name)
1912 pub trait ToPolyTraitRef<'tcx> {
1913 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1916 impl<'tcx> ToPolyTraitRef<'tcx> for Rc<TraitRef<'tcx>> {
1917 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1918 assert!(!self.has_escaping_regions());
1919 ty::Binder(self.clone())
1923 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1924 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1925 // We are just preserving the binder levels here
1926 ty::Binder(self.0.trait_ref.clone())
1930 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
1931 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1932 // Note: unlike with TraitRef::to_poly_trait_ref(),
1933 // self.0.trait_ref is permitted to have escaping regions.
1934 // This is because here `self` has a `Binder` and so does our
1935 // return value, so we are preserving the number of binding
1937 ty::Binder(self.0.projection_ty.trait_ref.clone())
1941 pub trait AsPredicate<'tcx> {
1942 fn as_predicate(&self) -> Predicate<'tcx>;
1945 impl<'tcx> AsPredicate<'tcx> for Rc<TraitRef<'tcx>> {
1946 fn as_predicate(&self) -> Predicate<'tcx> {
1947 // we're about to add a binder, so let's check that we don't
1948 // accidentally capture anything, or else that might be some
1949 // weird debruijn accounting.
1950 assert!(!self.has_escaping_regions());
1952 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
1953 trait_ref: self.clone()
1958 impl<'tcx> AsPredicate<'tcx> for PolyTraitRef<'tcx> {
1959 fn as_predicate(&self) -> Predicate<'tcx> {
1960 ty::Predicate::Trait(self.to_poly_trait_predicate())
1964 impl<'tcx> AsPredicate<'tcx> for PolyEquatePredicate<'tcx> {
1965 fn as_predicate(&self) -> Predicate<'tcx> {
1966 Predicate::Equate(self.clone())
1970 impl<'tcx> AsPredicate<'tcx> for PolyRegionOutlivesPredicate {
1971 fn as_predicate(&self) -> Predicate<'tcx> {
1972 Predicate::RegionOutlives(self.clone())
1976 impl<'tcx> AsPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1977 fn as_predicate(&self) -> Predicate<'tcx> {
1978 Predicate::TypeOutlives(self.clone())
1982 impl<'tcx> AsPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1983 fn as_predicate(&self) -> Predicate<'tcx> {
1984 Predicate::Projection(self.clone())
1988 impl<'tcx> Predicate<'tcx> {
1989 pub fn has_escaping_regions(&self) -> bool {
1991 Predicate::Trait(ref trait_ref) => trait_ref.has_escaping_regions(),
1992 Predicate::Equate(ref p) => p.has_escaping_regions(),
1993 Predicate::RegionOutlives(ref p) => p.has_escaping_regions(),
1994 Predicate::TypeOutlives(ref p) => p.has_escaping_regions(),
1995 Predicate::Projection(ref p) => p.has_escaping_regions(),
1999 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
2001 Predicate::Trait(ref t) => {
2002 Some(t.to_poly_trait_ref())
2004 Predicate::Projection(..) |
2005 Predicate::Equate(..) |
2006 Predicate::RegionOutlives(..) |
2007 Predicate::TypeOutlives(..) => {
2014 /// Represents the bounds declared on a particular set of type
2015 /// parameters. Should eventually be generalized into a flag list of
2016 /// where clauses. You can obtain a `GenericBounds` list from a
2017 /// `Generics` by using the `to_bounds` method. Note that this method
2018 /// reflects an important semantic invariant of `GenericBounds`: while
2019 /// the bounds in a `Generics` are expressed in terms of the bound type
2020 /// parameters of the impl/trait/whatever, a `GenericBounds` instance
2021 /// represented a set of bounds for some particular instantiation,
2022 /// meaning that the generic parameters have been substituted with
2027 /// struct Foo<T,U:Bar<T>> { ... }
2029 /// Here, the `Generics` for `Foo` would contain a list of bounds like
2030 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
2031 /// like `Foo<int,uint>`, then the `GenericBounds` would be `[[],
2032 /// [uint:Bar<int>]]`.
2033 #[derive(Clone, Show)]
2034 pub struct GenericBounds<'tcx> {
2035 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
2038 impl<'tcx> GenericBounds<'tcx> {
2039 pub fn empty() -> GenericBounds<'tcx> {
2040 GenericBounds { predicates: VecPerParamSpace::empty() }
2043 pub fn has_escaping_regions(&self) -> bool {
2044 self.predicates.any(|p| p.has_escaping_regions())
2047 pub fn is_empty(&self) -> bool {
2048 self.predicates.is_empty()
2052 impl<'tcx> TraitRef<'tcx> {
2053 pub fn new(def_id: ast::DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
2054 TraitRef { def_id: def_id, substs: substs }
2057 pub fn self_ty(&self) -> Ty<'tcx> {
2058 self.substs.self_ty().unwrap()
2061 pub fn input_types(&self) -> &[Ty<'tcx>] {
2062 // Select only the "input types" from a trait-reference. For
2063 // now this is all the types that appear in the
2064 // trait-reference, but it should eventually exclude
2065 // associated types.
2066 self.substs.types.as_slice()
2070 /// When type checking, we use the `ParameterEnvironment` to track
2071 /// details about the type/lifetime parameters that are in scope.
2072 /// It primarily stores the bounds information.
2074 /// Note: This information might seem to be redundant with the data in
2075 /// `tcx.ty_param_defs`, but it is not. That table contains the
2076 /// parameter definitions from an "outside" perspective, but this
2077 /// struct will contain the bounds for a parameter as seen from inside
2078 /// the function body. Currently the only real distinction is that
2079 /// bound lifetime parameters are replaced with free ones, but in the
2080 /// future I hope to refine the representation of types so as to make
2081 /// more distinctions clearer.
2083 pub struct ParameterEnvironment<'a, 'tcx:'a> {
2084 pub tcx: &'a ctxt<'tcx>,
2086 /// A substitution that can be applied to move from
2087 /// the "outer" view of a type or method to the "inner" view.
2088 /// In general, this means converting from bound parameters to
2089 /// free parameters. Since we currently represent bound/free type
2090 /// parameters in the same way, this only has an effect on regions.
2091 pub free_substs: Substs<'tcx>,
2093 /// Each type parameter has an implicit region bound that
2094 /// indicates it must outlive at least the function body (the user
2095 /// may specify stronger requirements). This field indicates the
2096 /// region of the callee.
2097 pub implicit_region_bound: ty::Region,
2099 /// Obligations that the caller must satisfy. This is basically
2100 /// the set of bounds on the in-scope type parameters, translated
2101 /// into Obligations.
2102 pub caller_bounds: ty::GenericBounds<'tcx>,
2104 /// Caches the results of trait selection. This cache is used
2105 /// for things that have to do with the parameters in scope.
2106 pub selection_cache: traits::SelectionCache<'tcx>,
2109 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
2110 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
2111 match cx.map.find(id) {
2112 Some(ast_map::NodeImplItem(ref impl_item)) => {
2114 ast::MethodImplItem(ref method) => {
2115 let method_def_id = ast_util::local_def(id);
2116 match ty::impl_or_trait_item(cx, method_def_id) {
2117 MethodTraitItem(ref method_ty) => {
2118 let method_generics = &method_ty.generics;
2119 construct_parameter_environment(
2122 method.pe_body().id)
2124 TypeTraitItem(_) => {
2126 .bug("ParameterEnvironment::for_item(): \
2127 can't create a parameter environment \
2128 for type trait items")
2132 ast::TypeImplItem(_) => {
2133 cx.sess.bug("ParameterEnvironment::for_item(): \
2134 can't create a parameter environment \
2135 for type impl items")
2139 Some(ast_map::NodeTraitItem(trait_method)) => {
2140 match *trait_method {
2141 ast::RequiredMethod(ref required) => {
2142 cx.sess.span_bug(required.span,
2143 "ParameterEnvironment::for_item():
2144 can't create a parameter \
2145 environment for required trait \
2148 ast::ProvidedMethod(ref method) => {
2149 let method_def_id = ast_util::local_def(id);
2150 match ty::impl_or_trait_item(cx, method_def_id) {
2151 MethodTraitItem(ref method_ty) => {
2152 let method_generics = &method_ty.generics;
2153 construct_parameter_environment(
2156 method.pe_body().id)
2158 TypeTraitItem(_) => {
2160 .bug("ParameterEnvironment::for_item(): \
2161 can't create a parameter environment \
2162 for type trait items")
2166 ast::TypeTraitItem(_) => {
2167 cx.sess.bug("ParameterEnvironment::from_item(): \
2168 can't create a parameter environment \
2169 for type trait items")
2173 Some(ast_map::NodeItem(item)) => {
2175 ast::ItemFn(_, _, _, _, ref body) => {
2176 // We assume this is a function.
2177 let fn_def_id = ast_util::local_def(id);
2178 let fn_pty = ty::lookup_item_type(cx, fn_def_id);
2180 construct_parameter_environment(cx,
2185 ast::ItemStruct(..) |
2187 ast::ItemConst(..) |
2188 ast::ItemStatic(..) => {
2189 let def_id = ast_util::local_def(id);
2190 let pty = ty::lookup_item_type(cx, def_id);
2191 construct_parameter_environment(cx, &pty.generics, id)
2194 cx.sess.span_bug(item.span,
2195 "ParameterEnvironment::from_item():
2196 can't create a parameter \
2197 environment for this kind of item")
2201 Some(ast_map::NodeExpr(..)) => {
2202 // This is a convenience to allow closures to work.
2203 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
2206 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
2207 `{}` is not an item",
2208 cx.map.node_to_string(id))[])
2214 /// A "type scheme", in ML terminology, is a type combined with some
2215 /// set of generic types that the type is, well, generic over. In Rust
2216 /// terms, it is the "type" of a fn item or struct -- this type will
2217 /// include various generic parameters that must be substituted when
2218 /// the item/struct is referenced. That is called converting the type
2219 /// scheme to a monotype.
2221 /// - `generics`: the set of type parameters and their bounds
2222 /// - `ty`: the base types, which may reference the parameters defined
2225 /// Note that TypeSchemes are also sometimes called "polytypes" (and
2226 /// in fact this struct used to carry that name, so you may find some
2227 /// stray references in a comment or something). We try to reserve the
2228 /// "poly" prefix to refer to higher-ranked things, as in
2230 #[derive(Clone, Show)]
2231 pub struct TypeScheme<'tcx> {
2232 pub generics: Generics<'tcx>,
2236 /// As `TypeScheme` but for a trait ref.
2237 pub struct TraitDef<'tcx> {
2238 pub unsafety: ast::Unsafety,
2240 /// Generic type definitions. Note that `Self` is listed in here
2241 /// as having a single bound, the trait itself (e.g., in the trait
2242 /// `Eq`, there is a single bound `Self : Eq`). This is so that
2243 /// default methods get to assume that the `Self` parameters
2244 /// implements the trait.
2245 pub generics: Generics<'tcx>,
2247 /// The "supertrait" bounds.
2248 pub bounds: ParamBounds<'tcx>,
2250 pub trait_ref: Rc<ty::TraitRef<'tcx>>,
2252 /// A list of the associated types defined in this trait. Useful
2253 /// for resolving `X::Foo` type markers.
2254 pub associated_type_names: Vec<ast::Name>,
2257 /// Records the substitutions used to translate the polytype for an
2258 /// item into the monotype of an item reference.
2260 pub struct ItemSubsts<'tcx> {
2261 pub substs: Substs<'tcx>,
2264 /// Records information about each unboxed closure.
2266 pub struct UnboxedClosure<'tcx> {
2267 /// The type of the unboxed closure.
2268 pub closure_type: ClosureTy<'tcx>,
2269 /// The kind of unboxed closure this is.
2270 pub kind: UnboxedClosureKind,
2273 #[derive(Clone, Copy, PartialEq, Eq, Show)]
2274 pub enum UnboxedClosureKind {
2275 FnUnboxedClosureKind,
2276 FnMutUnboxedClosureKind,
2277 FnOnceUnboxedClosureKind,
2280 impl UnboxedClosureKind {
2281 pub fn trait_did(&self, cx: &ctxt) -> ast::DefId {
2282 let result = match *self {
2283 FnUnboxedClosureKind => cx.lang_items.require(FnTraitLangItem),
2284 FnMutUnboxedClosureKind => {
2285 cx.lang_items.require(FnMutTraitLangItem)
2287 FnOnceUnboxedClosureKind => {
2288 cx.lang_items.require(FnOnceTraitLangItem)
2292 Ok(trait_did) => trait_did,
2293 Err(err) => cx.sess.fatal(&err[]),
2298 pub trait UnboxedClosureTyper<'tcx> {
2299 fn param_env<'a>(&'a self) -> &'a ty::ParameterEnvironment<'a, 'tcx>;
2301 fn unboxed_closure_kind(&self,
2303 -> ty::UnboxedClosureKind;
2305 fn unboxed_closure_type(&self,
2307 substs: &subst::Substs<'tcx>)
2308 -> ty::ClosureTy<'tcx>;
2310 // Returns `None` if the upvar types cannot yet be definitively determined.
2311 fn unboxed_closure_upvars(&self,
2313 substs: &Substs<'tcx>)
2314 -> Option<Vec<UnboxedClosureUpvar<'tcx>>>;
2317 impl<'tcx> CommonTypes<'tcx> {
2318 fn new(arena: &'tcx TypedArena<TyS<'tcx>>,
2319 interner: &mut FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>)
2320 -> CommonTypes<'tcx>
2323 bool: intern_ty(arena, interner, ty_bool),
2324 char: intern_ty(arena, interner, ty_char),
2325 err: intern_ty(arena, interner, ty_err),
2326 int: intern_ty(arena, interner, ty_int(ast::TyIs(false))),
2327 i8: intern_ty(arena, interner, ty_int(ast::TyI8)),
2328 i16: intern_ty(arena, interner, ty_int(ast::TyI16)),
2329 i32: intern_ty(arena, interner, ty_int(ast::TyI32)),
2330 i64: intern_ty(arena, interner, ty_int(ast::TyI64)),
2331 uint: intern_ty(arena, interner, ty_uint(ast::TyUs(false))),
2332 u8: intern_ty(arena, interner, ty_uint(ast::TyU8)),
2333 u16: intern_ty(arena, interner, ty_uint(ast::TyU16)),
2334 u32: intern_ty(arena, interner, ty_uint(ast::TyU32)),
2335 u64: intern_ty(arena, interner, ty_uint(ast::TyU64)),
2336 f32: intern_ty(arena, interner, ty_float(ast::TyF32)),
2337 f64: intern_ty(arena, interner, ty_float(ast::TyF64)),
2342 pub fn mk_ctxt<'tcx>(s: Session,
2343 arenas: &'tcx CtxtArenas<'tcx>,
2345 named_region_map: resolve_lifetime::NamedRegionMap,
2346 map: ast_map::Map<'tcx>,
2347 freevars: RefCell<FreevarMap>,
2348 capture_modes: RefCell<CaptureModeMap>,
2349 region_maps: middle::region::RegionMaps,
2350 lang_items: middle::lang_items::LanguageItems,
2351 stability: stability::Index) -> ctxt<'tcx>
2353 let mut interner = FnvHashMap();
2354 let common_types = CommonTypes::new(&arenas.type_, &mut interner);
2358 interner: RefCell::new(interner),
2359 substs_interner: RefCell::new(FnvHashMap()),
2360 bare_fn_interner: RefCell::new(FnvHashMap()),
2361 region_interner: RefCell::new(FnvHashMap()),
2362 types: common_types,
2363 named_region_map: named_region_map,
2364 item_variance_map: RefCell::new(DefIdMap()),
2365 variance_computed: Cell::new(false),
2368 region_maps: region_maps,
2369 node_types: RefCell::new(FnvHashMap()),
2370 item_substs: RefCell::new(NodeMap()),
2371 trait_refs: RefCell::new(NodeMap()),
2372 trait_defs: RefCell::new(DefIdMap()),
2373 object_cast_map: RefCell::new(NodeMap()),
2375 intrinsic_defs: RefCell::new(DefIdMap()),
2377 tcache: RefCell::new(DefIdMap()),
2378 rcache: RefCell::new(FnvHashMap()),
2379 short_names_cache: RefCell::new(FnvHashMap()),
2380 tc_cache: RefCell::new(FnvHashMap()),
2381 ast_ty_to_ty_cache: RefCell::new(NodeMap()),
2382 enum_var_cache: RefCell::new(DefIdMap()),
2383 impl_or_trait_items: RefCell::new(DefIdMap()),
2384 trait_item_def_ids: RefCell::new(DefIdMap()),
2385 trait_items_cache: RefCell::new(DefIdMap()),
2386 impl_trait_cache: RefCell::new(DefIdMap()),
2387 ty_param_defs: RefCell::new(NodeMap()),
2388 adjustments: RefCell::new(NodeMap()),
2389 normalized_cache: RefCell::new(FnvHashMap()),
2390 lang_items: lang_items,
2391 provided_method_sources: RefCell::new(DefIdMap()),
2392 struct_fields: RefCell::new(DefIdMap()),
2393 destructor_for_type: RefCell::new(DefIdMap()),
2394 destructors: RefCell::new(DefIdSet()),
2395 trait_impls: RefCell::new(DefIdMap()),
2396 inherent_impls: RefCell::new(DefIdMap()),
2397 impl_items: RefCell::new(DefIdMap()),
2398 used_unsafe: RefCell::new(NodeSet()),
2399 used_mut_nodes: RefCell::new(NodeSet()),
2400 populated_external_types: RefCell::new(DefIdSet()),
2401 populated_external_traits: RefCell::new(DefIdSet()),
2402 upvar_borrow_map: RefCell::new(FnvHashMap()),
2403 extern_const_statics: RefCell::new(DefIdMap()),
2404 extern_const_variants: RefCell::new(DefIdMap()),
2405 method_map: RefCell::new(FnvHashMap()),
2406 dependency_formats: RefCell::new(FnvHashMap()),
2407 unboxed_closures: RefCell::new(DefIdMap()),
2408 node_lint_levels: RefCell::new(FnvHashMap()),
2409 transmute_restrictions: RefCell::new(Vec::new()),
2410 stability: RefCell::new(stability),
2411 capture_modes: capture_modes,
2412 associated_types: RefCell::new(DefIdMap()),
2413 selection_cache: traits::SelectionCache::new(),
2414 repr_hint_cache: RefCell::new(DefIdMap()),
2415 type_impls_copy_cache: RefCell::new(HashMap::new()),
2416 type_impls_sized_cache: RefCell::new(HashMap::new()),
2417 object_safety_cache: RefCell::new(DefIdMap()),
2421 // Type constructors
2423 impl<'tcx> ctxt<'tcx> {
2424 pub fn mk_substs(&self, substs: Substs<'tcx>) -> &'tcx Substs<'tcx> {
2425 if let Some(substs) = self.substs_interner.borrow().get(&substs) {
2429 let substs = self.arenas.substs.alloc(substs);
2430 self.substs_interner.borrow_mut().insert(substs, substs);
2434 pub fn mk_bare_fn(&self, bare_fn: BareFnTy<'tcx>) -> &'tcx BareFnTy<'tcx> {
2435 if let Some(bare_fn) = self.bare_fn_interner.borrow().get(&bare_fn) {
2439 let bare_fn = self.arenas.bare_fn.alloc(bare_fn);
2440 self.bare_fn_interner.borrow_mut().insert(bare_fn, bare_fn);
2444 pub fn mk_region(&self, region: Region) -> &'tcx Region {
2445 if let Some(region) = self.region_interner.borrow().get(®ion) {
2449 let region = self.arenas.region.alloc(region);
2450 self.region_interner.borrow_mut().insert(region, region);
2454 pub fn unboxed_closure_kind(&self,
2456 -> ty::UnboxedClosureKind
2458 self.unboxed_closures.borrow()[def_id].kind
2461 pub fn unboxed_closure_type(&self,
2463 substs: &subst::Substs<'tcx>)
2464 -> ty::ClosureTy<'tcx>
2466 self.unboxed_closures.borrow()[def_id].closure_type.subst(self, substs)
2470 // Interns a type/name combination, stores the resulting box in cx.interner,
2471 // and returns the box as cast to an unsafe ptr (see comments for Ty above).
2472 pub fn mk_t<'tcx>(cx: &ctxt<'tcx>, st: sty<'tcx>) -> Ty<'tcx> {
2473 let mut interner = cx.interner.borrow_mut();
2474 intern_ty(&cx.arenas.type_, &mut *interner, st)
2477 fn intern_ty<'tcx>(type_arena: &'tcx TypedArena<TyS<'tcx>>,
2478 interner: &mut FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>,
2482 match interner.get(&st) {
2483 Some(ty) => return *ty,
2487 let flags = FlagComputation::for_sty(&st);
2489 let ty = type_arena.alloc(TyS {
2492 region_depth: flags.depth,
2495 debug!("Interned type: {:?} Pointer: {:?}",
2496 ty, ty as *const _);
2498 interner.insert(InternedTy { ty: ty }, ty);
2503 struct FlagComputation {
2506 // maximum depth of any bound region that we have seen thus far
2510 impl FlagComputation {
2511 fn new() -> FlagComputation {
2512 FlagComputation { flags: NO_TYPE_FLAGS, depth: 0 }
2515 fn for_sty(st: &sty) -> FlagComputation {
2516 let mut result = FlagComputation::new();
2521 fn add_flags(&mut self, flags: TypeFlags) {
2522 self.flags = self.flags | flags;
2525 fn add_depth(&mut self, depth: u32) {
2526 if depth > self.depth {
2531 /// Adds the flags/depth from a set of types that appear within the current type, but within a
2533 fn add_bound_computation(&mut self, computation: &FlagComputation) {
2534 self.add_flags(computation.flags);
2536 // The types that contributed to `computation` occured within
2537 // a region binder, so subtract one from the region depth
2538 // within when adding the depth to `self`.
2539 let depth = computation.depth;
2541 self.add_depth(depth - 1);
2545 fn add_sty(&mut self, st: &sty) {
2555 // You might think that we could just return ty_err for
2556 // any type containing ty_err as a component, and get
2557 // rid of the HAS_TY_ERR flag -- likewise for ty_bot (with
2558 // the exception of function types that return bot).
2559 // But doing so caused sporadic memory corruption, and
2560 // neither I (tjc) nor nmatsakis could figure out why,
2561 // so we're doing it this way.
2563 self.add_flags(HAS_TY_ERR)
2566 &ty_param(ref p) => {
2567 if p.space == subst::SelfSpace {
2568 self.add_flags(HAS_SELF);
2570 self.add_flags(HAS_PARAMS);
2574 &ty_unboxed_closure(_, region, substs) => {
2575 self.add_region(*region);
2576 self.add_substs(substs);
2580 self.add_flags(HAS_TY_INFER)
2583 &ty_enum(_, substs) | &ty_struct(_, substs) => {
2584 self.add_substs(substs);
2587 &ty_projection(ref data) => {
2588 self.add_flags(HAS_PROJECTION);
2589 self.add_projection_ty(data);
2592 &ty_trait(box TyTrait { ref principal, ref bounds }) => {
2593 let mut computation = FlagComputation::new();
2594 computation.add_substs(principal.0.substs);
2595 for projection_bound in bounds.projection_bounds.iter() {
2596 let mut proj_computation = FlagComputation::new();
2597 proj_computation.add_projection_predicate(&projection_bound.0);
2598 computation.add_bound_computation(&proj_computation);
2600 self.add_bound_computation(&computation);
2602 self.add_bounds(bounds);
2605 &ty_uniq(tt) | &ty_vec(tt, _) | &ty_open(tt) => {
2613 &ty_rptr(r, ref m) => {
2614 self.add_region(*r);
2618 &ty_tup(ref ts) => {
2619 self.add_tys(&ts[]);
2622 &ty_bare_fn(_, ref f) => {
2623 self.add_fn_sig(&f.sig);
2628 fn add_ty(&mut self, ty: Ty) {
2629 self.add_flags(ty.flags);
2630 self.add_depth(ty.region_depth);
2633 fn add_tys(&mut self, tys: &[Ty]) {
2634 for &ty in tys.iter() {
2639 fn add_fn_sig(&mut self, fn_sig: &PolyFnSig) {
2640 let mut computation = FlagComputation::new();
2642 computation.add_tys(&fn_sig.0.inputs[]);
2644 if let ty::FnConverging(output) = fn_sig.0.output {
2645 computation.add_ty(output);
2648 self.add_bound_computation(&computation);
2651 fn add_region(&mut self, r: Region) {
2652 self.add_flags(HAS_REGIONS);
2654 ty::ReInfer(_) => { self.add_flags(HAS_RE_INFER); }
2655 ty::ReLateBound(debruijn, _) => {
2656 self.add_flags(HAS_RE_LATE_BOUND);
2657 self.add_depth(debruijn.depth);
2663 fn add_projection_predicate(&mut self, projection_predicate: &ProjectionPredicate) {
2664 self.add_projection_ty(&projection_predicate.projection_ty);
2665 self.add_ty(projection_predicate.ty);
2668 fn add_projection_ty(&mut self, projection_ty: &ProjectionTy) {
2669 self.add_substs(projection_ty.trait_ref.substs);
2672 fn add_substs(&mut self, substs: &Substs) {
2673 self.add_tys(substs.types.as_slice());
2674 match substs.regions {
2675 subst::ErasedRegions => {}
2676 subst::NonerasedRegions(ref regions) => {
2677 for &r in regions.iter() {
2684 fn add_bounds(&mut self, bounds: &ExistentialBounds) {
2685 self.add_region(bounds.region_bound);
2689 pub fn mk_mach_int<'tcx>(tcx: &ctxt<'tcx>, tm: ast::IntTy) -> Ty<'tcx> {
2691 ast::TyIs(_) => tcx.types.int,
2692 ast::TyI8 => tcx.types.i8,
2693 ast::TyI16 => tcx.types.i16,
2694 ast::TyI32 => tcx.types.i32,
2695 ast::TyI64 => tcx.types.i64,
2699 pub fn mk_mach_uint<'tcx>(tcx: &ctxt<'tcx>, tm: ast::UintTy) -> Ty<'tcx> {
2701 ast::TyUs(_) => tcx.types.uint,
2702 ast::TyU8 => tcx.types.u8,
2703 ast::TyU16 => tcx.types.u16,
2704 ast::TyU32 => tcx.types.u32,
2705 ast::TyU64 => tcx.types.u64,
2709 pub fn mk_mach_float<'tcx>(tcx: &ctxt<'tcx>, tm: ast::FloatTy) -> Ty<'tcx> {
2711 ast::TyF32 => tcx.types.f32,
2712 ast::TyF64 => tcx.types.f64,
2716 pub fn mk_str<'tcx>(cx: &ctxt<'tcx>) -> Ty<'tcx> {
2720 pub fn mk_str_slice<'tcx>(cx: &ctxt<'tcx>, r: &'tcx Region, m: ast::Mutability) -> Ty<'tcx> {
2723 ty: mk_t(cx, ty_str),
2728 pub fn mk_enum<'tcx>(cx: &ctxt<'tcx>, did: ast::DefId, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
2729 // take a copy of substs so that we own the vectors inside
2730 mk_t(cx, ty_enum(did, substs))
2733 pub fn mk_uniq<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> { mk_t(cx, ty_uniq(ty)) }
2735 pub fn mk_ptr<'tcx>(cx: &ctxt<'tcx>, tm: mt<'tcx>) -> Ty<'tcx> { mk_t(cx, ty_ptr(tm)) }
2737 pub fn mk_rptr<'tcx>(cx: &ctxt<'tcx>, r: &'tcx Region, tm: mt<'tcx>) -> Ty<'tcx> {
2738 mk_t(cx, ty_rptr(r, tm))
2741 pub fn mk_mut_rptr<'tcx>(cx: &ctxt<'tcx>, r: &'tcx Region, ty: Ty<'tcx>) -> Ty<'tcx> {
2742 mk_rptr(cx, r, mt {ty: ty, mutbl: ast::MutMutable})
2744 pub fn mk_imm_rptr<'tcx>(cx: &ctxt<'tcx>, r: &'tcx Region, ty: Ty<'tcx>) -> Ty<'tcx> {
2745 mk_rptr(cx, r, mt {ty: ty, mutbl: ast::MutImmutable})
2748 pub fn mk_mut_ptr<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
2749 mk_ptr(cx, mt {ty: ty, mutbl: ast::MutMutable})
2752 pub fn mk_imm_ptr<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
2753 mk_ptr(cx, mt {ty: ty, mutbl: ast::MutImmutable})
2756 pub fn mk_nil_ptr<'tcx>(cx: &ctxt<'tcx>) -> Ty<'tcx> {
2757 mk_ptr(cx, mt {ty: mk_nil(cx), mutbl: ast::MutImmutable})
2760 pub fn mk_vec<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>, sz: Option<uint>) -> Ty<'tcx> {
2761 mk_t(cx, ty_vec(ty, sz))
2764 pub fn mk_slice<'tcx>(cx: &ctxt<'tcx>, r: &'tcx Region, tm: mt<'tcx>) -> Ty<'tcx> {
2767 ty: mk_vec(cx, tm.ty, None),
2772 pub fn mk_tup<'tcx>(cx: &ctxt<'tcx>, ts: Vec<Ty<'tcx>>) -> Ty<'tcx> {
2773 mk_t(cx, ty_tup(ts))
2776 pub fn mk_nil<'tcx>(cx: &ctxt<'tcx>) -> Ty<'tcx> {
2777 mk_tup(cx, Vec::new())
2780 pub fn mk_bare_fn<'tcx>(cx: &ctxt<'tcx>,
2781 opt_def_id: Option<ast::DefId>,
2782 fty: &'tcx BareFnTy<'tcx>) -> Ty<'tcx> {
2783 mk_t(cx, ty_bare_fn(opt_def_id, fty))
2786 pub fn mk_ctor_fn<'tcx>(cx: &ctxt<'tcx>,
2788 input_tys: &[Ty<'tcx>],
2789 output: Ty<'tcx>) -> Ty<'tcx> {
2790 let input_args = input_tys.iter().map(|ty| *ty).collect();
2793 cx.mk_bare_fn(BareFnTy {
2794 unsafety: ast::Unsafety::Normal,
2796 sig: ty::Binder(FnSig {
2798 output: ty::FnConverging(output),
2804 pub fn mk_trait<'tcx>(cx: &ctxt<'tcx>,
2805 principal: ty::PolyTraitRef<'tcx>,
2806 bounds: ExistentialBounds<'tcx>)
2809 assert!(bound_list_is_sorted(bounds.projection_bounds.as_slice()));
2811 let inner = box TyTrait {
2812 principal: principal,
2815 mk_t(cx, ty_trait(inner))
2818 fn bound_list_is_sorted(bounds: &[ty::PolyProjectionPredicate]) -> bool {
2819 bounds.len() == 0 ||
2820 bounds[1..].iter().enumerate().all(
2821 |(index, bound)| bounds[index].sort_key() <= bound.sort_key())
2824 pub fn sort_bounds_list(bounds: &mut [ty::PolyProjectionPredicate]) {
2825 bounds.sort_by(|a, b| a.sort_key().cmp(&b.sort_key()))
2828 pub fn mk_projection<'tcx>(cx: &ctxt<'tcx>,
2829 trait_ref: Rc<ty::TraitRef<'tcx>>,
2830 item_name: ast::Name)
2832 // take a copy of substs so that we own the vectors inside
2833 let inner = ProjectionTy { trait_ref: trait_ref, item_name: item_name };
2834 mk_t(cx, ty_projection(inner))
2837 pub fn mk_struct<'tcx>(cx: &ctxt<'tcx>, struct_id: ast::DefId,
2838 substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
2839 // take a copy of substs so that we own the vectors inside
2840 mk_t(cx, ty_struct(struct_id, substs))
2843 pub fn mk_unboxed_closure<'tcx>(cx: &ctxt<'tcx>, closure_id: ast::DefId,
2844 region: &'tcx Region, substs: &'tcx Substs<'tcx>)
2846 mk_t(cx, ty_unboxed_closure(closure_id, region, substs))
2849 pub fn mk_var<'tcx>(cx: &ctxt<'tcx>, v: TyVid) -> Ty<'tcx> {
2850 mk_infer(cx, TyVar(v))
2853 pub fn mk_int_var<'tcx>(cx: &ctxt<'tcx>, v: IntVid) -> Ty<'tcx> {
2854 mk_infer(cx, IntVar(v))
2857 pub fn mk_float_var<'tcx>(cx: &ctxt<'tcx>, v: FloatVid) -> Ty<'tcx> {
2858 mk_infer(cx, FloatVar(v))
2861 pub fn mk_infer<'tcx>(cx: &ctxt<'tcx>, it: InferTy) -> Ty<'tcx> {
2862 mk_t(cx, ty_infer(it))
2865 pub fn mk_param<'tcx>(cx: &ctxt<'tcx>,
2866 space: subst::ParamSpace,
2868 name: ast::Name) -> Ty<'tcx> {
2869 mk_t(cx, ty_param(ParamTy { space: space, idx: index, name: name }))
2872 pub fn mk_self_type<'tcx>(cx: &ctxt<'tcx>) -> Ty<'tcx> {
2873 mk_param(cx, subst::SelfSpace, 0, special_idents::type_self.name)
2876 pub fn mk_param_from_def<'tcx>(cx: &ctxt<'tcx>, def: &TypeParameterDef) -> Ty<'tcx> {
2877 mk_param(cx, def.space, def.index, def.name)
2880 pub fn mk_open<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> { mk_t(cx, ty_open(ty)) }
2882 impl<'tcx> TyS<'tcx> {
2883 /// Iterator that walks `self` and any types reachable from
2884 /// `self`, in depth-first order. Note that just walks the types
2885 /// that appear in `self`, it does not descend into the fields of
2886 /// structs or variants. For example:
2890 /// Foo<Bar<int>> => { Foo<Bar<int>>, Bar<int>, int }
2891 /// [int] => { [int], int }
2893 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2894 TypeWalker::new(self)
2897 /// Iterator that walks types reachable from `self`, in
2898 /// depth-first order. Note that this is a shallow walk. For
2903 /// Foo<Bar<int>> => { Bar<int>, int }
2904 /// [int] => { int }
2906 pub fn walk_children(&'tcx self) -> TypeWalker<'tcx> {
2907 // Walks type reachable from `self` but not `self
2908 let mut walker = self.walk();
2909 let r = walker.next();
2910 assert_eq!(r, Some(self));
2915 pub fn walk_ty<'tcx, F>(ty_root: Ty<'tcx>, mut f: F)
2916 where F: FnMut(Ty<'tcx>),
2918 for ty in ty_root.walk() {
2923 /// Walks `ty` and any types appearing within `ty`, invoking the
2924 /// callback `f` on each type. If the callback returns false, then the
2925 /// children of the current type are ignored.
2927 /// Note: prefer `ty.walk()` where possible.
2928 pub fn maybe_walk_ty<'tcx,F>(ty_root: Ty<'tcx>, mut f: F)
2929 where F : FnMut(Ty<'tcx>) -> bool
2931 let mut walker = ty_root.walk();
2932 while let Some(ty) = walker.next() {
2934 walker.skip_current_subtree();
2939 // Folds types from the bottom up.
2940 pub fn fold_ty<'tcx, F>(cx: &ctxt<'tcx>, t0: Ty<'tcx>,
2943 F: FnMut(Ty<'tcx>) -> Ty<'tcx>,
2945 let mut f = ty_fold::BottomUpFolder {tcx: cx, fldop: fldop};
2950 pub fn new(space: subst::ParamSpace,
2954 ParamTy { space: space, idx: index, name: name }
2957 pub fn for_self() -> ParamTy {
2958 ParamTy::new(subst::SelfSpace, 0, special_idents::type_self.name)
2961 pub fn for_def(def: &TypeParameterDef) -> ParamTy {
2962 ParamTy::new(def.space, def.index, def.name)
2965 pub fn to_ty<'tcx>(self, tcx: &ty::ctxt<'tcx>) -> Ty<'tcx> {
2966 ty::mk_param(tcx, self.space, self.idx, self.name)
2969 pub fn is_self(&self) -> bool {
2970 self.space == subst::SelfSpace && self.idx == 0
2974 impl<'tcx> ItemSubsts<'tcx> {
2975 pub fn empty() -> ItemSubsts<'tcx> {
2976 ItemSubsts { substs: Substs::empty() }
2979 pub fn is_noop(&self) -> bool {
2980 self.substs.is_noop()
2984 impl<'tcx> ParamBounds<'tcx> {
2985 pub fn empty() -> ParamBounds<'tcx> {
2987 builtin_bounds: empty_builtin_bounds(),
2988 trait_bounds: Vec::new(),
2989 region_bounds: Vec::new(),
2990 projection_bounds: Vec::new(),
2997 pub fn type_is_nil(ty: Ty) -> bool {
2999 ty_tup(ref tys) => tys.is_empty(),
3004 pub fn type_is_error(ty: Ty) -> bool {
3005 ty.flags.intersects(HAS_TY_ERR)
3008 pub fn type_needs_subst(ty: Ty) -> bool {
3009 ty.flags.intersects(NEEDS_SUBST)
3012 pub fn trait_ref_contains_error(tref: &ty::TraitRef) -> bool {
3013 tref.substs.types.any(|&ty| type_is_error(ty))
3016 pub fn type_is_ty_var(ty: Ty) -> bool {
3018 ty_infer(TyVar(_)) => true,
3023 pub fn type_is_bool(ty: Ty) -> bool { ty.sty == ty_bool }
3025 pub fn type_is_self(ty: Ty) -> bool {
3027 ty_param(ref p) => p.space == subst::SelfSpace,
3032 fn type_is_slice(ty: Ty) -> bool {
3034 ty_ptr(mt) | ty_rptr(_, mt) => match mt.ty.sty {
3035 ty_vec(_, None) | ty_str => true,
3042 pub fn type_is_vec(ty: Ty) -> bool {
3045 ty_ptr(mt{ty, ..}) | ty_rptr(_, mt{ty, ..}) |
3046 ty_uniq(ty) => match ty.sty {
3047 ty_vec(_, None) => true,
3054 pub fn type_is_structural(ty: Ty) -> bool {
3056 ty_struct(..) | ty_tup(_) | ty_enum(..) |
3057 ty_vec(_, Some(_)) | ty_unboxed_closure(..) => true,
3058 _ => type_is_slice(ty) | type_is_trait(ty)
3062 pub fn type_is_simd(cx: &ctxt, ty: Ty) -> bool {
3064 ty_struct(did, _) => lookup_simd(cx, did),
3069 pub fn sequence_element_type<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
3071 ty_vec(ty, _) => ty,
3072 ty_str => mk_mach_uint(cx, ast::TyU8),
3073 ty_open(ty) => sequence_element_type(cx, ty),
3074 _ => cx.sess.bug(&format!("sequence_element_type called on non-sequence value: {}",
3075 ty_to_string(cx, ty))[]),
3079 pub fn simd_type<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
3081 ty_struct(did, substs) => {
3082 let fields = lookup_struct_fields(cx, did);
3083 lookup_field_type(cx, did, fields[0].id, substs)
3085 _ => panic!("simd_type called on invalid type")
3089 pub fn simd_size(cx: &ctxt, ty: Ty) -> uint {
3091 ty_struct(did, _) => {
3092 let fields = lookup_struct_fields(cx, did);
3095 _ => panic!("simd_size called on invalid type")
3099 pub fn type_is_region_ptr(ty: Ty) -> bool {
3101 ty_rptr(..) => true,
3106 pub fn type_is_unsafe_ptr(ty: Ty) -> bool {
3108 ty_ptr(_) => return true,
3113 pub fn type_is_unique(ty: Ty) -> bool {
3115 ty_uniq(_) => match ty.sty {
3116 ty_trait(..) => false,
3124 A scalar type is one that denotes an atomic datum, with no sub-components.
3125 (A ty_ptr is scalar because it represents a non-managed pointer, so its
3126 contents are abstract to rustc.)
3128 pub fn type_is_scalar(ty: Ty) -> bool {
3130 ty_bool | ty_char | ty_int(_) | ty_float(_) | ty_uint(_) |
3131 ty_infer(IntVar(_)) | ty_infer(FloatVar(_)) |
3132 ty_bare_fn(..) | ty_ptr(_) => true,
3133 ty_tup(ref tys) if tys.is_empty() => true,
3138 /// Returns true if this type is a floating point type and false otherwise.
3139 pub fn type_is_floating_point(ty: Ty) -> bool {
3141 ty_float(_) => true,
3146 /// Type contents is how the type checker reasons about kinds.
3147 /// They track what kinds of things are found within a type. You can
3148 /// think of them as kind of an "anti-kind". They track the kinds of values
3149 /// and thinks that are contained in types. Having a larger contents for
3150 /// a type tends to rule that type *out* from various kinds. For example,
3151 /// a type that contains a reference is not sendable.
3153 /// The reason we compute type contents and not kinds is that it is
3154 /// easier for me (nmatsakis) to think about what is contained within
3155 /// a type than to think about what is *not* contained within a type.
3156 #[derive(Clone, Copy)]
3157 pub struct TypeContents {
3161 macro_rules! def_type_content_sets {
3162 (mod $mname:ident { $($name:ident = $bits:expr),+ }) => {
3163 #[allow(non_snake_case)]
3165 use middle::ty::TypeContents;
3167 #[allow(non_upper_case_globals)]
3168 pub const $name: TypeContents = TypeContents { bits: $bits };
3174 def_type_content_sets! {
3176 None = 0b0000_0000__0000_0000__0000,
3178 // Things that are interior to the value (first nibble):
3179 InteriorUnsized = 0b0000_0000__0000_0000__0001,
3180 InteriorUnsafe = 0b0000_0000__0000_0000__0010,
3181 InteriorParam = 0b0000_0000__0000_0000__0100,
3182 // InteriorAll = 0b00000000__00000000__1111,
3184 // Things that are owned by the value (second and third nibbles):
3185 OwnsOwned = 0b0000_0000__0000_0001__0000,
3186 OwnsDtor = 0b0000_0000__0000_0010__0000,
3187 OwnsManaged /* see [1] below */ = 0b0000_0000__0000_0100__0000,
3188 OwnsAll = 0b0000_0000__1111_1111__0000,
3190 // Things that are reachable by the value in any way (fourth nibble):
3191 ReachesBorrowed = 0b0000_0010__0000_0000__0000,
3192 // ReachesManaged /* see [1] below */ = 0b0000_0100__0000_0000__0000,
3193 ReachesMutable = 0b0000_1000__0000_0000__0000,
3194 ReachesFfiUnsafe = 0b0010_0000__0000_0000__0000,
3195 ReachesAll = 0b0011_1111__0000_0000__0000,
3197 // Things that mean drop glue is necessary
3198 NeedsDrop = 0b0000_0000__0000_0111__0000,
3200 // Things that prevent values from being considered sized
3201 Nonsized = 0b0000_0000__0000_0000__0001,
3203 // Bits to set when a managed value is encountered
3205 // [1] Do not set the bits TC::OwnsManaged or
3206 // TC::ReachesManaged directly, instead reference
3207 // TC::Managed to set them both at once.
3208 Managed = 0b0000_0100__0000_0100__0000,
3211 All = 0b1111_1111__1111_1111__1111
3216 pub fn when(&self, cond: bool) -> TypeContents {
3217 if cond {*self} else {TC::None}
3220 pub fn intersects(&self, tc: TypeContents) -> bool {
3221 (self.bits & tc.bits) != 0
3224 pub fn owns_managed(&self) -> bool {
3225 self.intersects(TC::OwnsManaged)
3228 pub fn owns_owned(&self) -> bool {
3229 self.intersects(TC::OwnsOwned)
3232 pub fn is_sized(&self, _: &ctxt) -> bool {
3233 !self.intersects(TC::Nonsized)
3236 pub fn interior_param(&self) -> bool {
3237 self.intersects(TC::InteriorParam)
3240 pub fn interior_unsafe(&self) -> bool {
3241 self.intersects(TC::InteriorUnsafe)
3244 pub fn interior_unsized(&self) -> bool {
3245 self.intersects(TC::InteriorUnsized)
3248 pub fn needs_drop(&self, _: &ctxt) -> bool {
3249 self.intersects(TC::NeedsDrop)
3252 /// Includes only those bits that still apply when indirected through a `Box` pointer
3253 pub fn owned_pointer(&self) -> TypeContents {
3255 *self & (TC::OwnsAll | TC::ReachesAll))
3258 /// Includes only those bits that still apply when indirected through a reference (`&`)
3259 pub fn reference(&self, bits: TypeContents) -> TypeContents {
3261 *self & TC::ReachesAll)
3264 /// Includes only those bits that still apply when indirected through a managed pointer (`@`)
3265 pub fn managed_pointer(&self) -> TypeContents {
3267 *self & TC::ReachesAll)
3270 /// Includes only those bits that still apply when indirected through an unsafe pointer (`*`)
3271 pub fn unsafe_pointer(&self) -> TypeContents {
3272 *self & TC::ReachesAll
3275 pub fn union<T, F>(v: &[T], mut f: F) -> TypeContents where
3276 F: FnMut(&T) -> TypeContents,
3278 v.iter().fold(TC::None, |tc, ty| tc | f(ty))
3281 pub fn has_dtor(&self) -> bool {
3282 self.intersects(TC::OwnsDtor)
3286 impl ops::BitOr for TypeContents {
3287 type Output = TypeContents;
3289 fn bitor(self, other: TypeContents) -> TypeContents {
3290 TypeContents {bits: self.bits | other.bits}
3294 impl ops::BitAnd for TypeContents {
3295 type Output = TypeContents;
3297 fn bitand(self, other: TypeContents) -> TypeContents {
3298 TypeContents {bits: self.bits & other.bits}
3302 impl ops::Sub for TypeContents {
3303 type Output = TypeContents;
3305 fn sub(self, other: TypeContents) -> TypeContents {
3306 TypeContents {bits: self.bits & !other.bits}
3310 impl fmt::Show for TypeContents {
3311 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
3312 write!(f, "TypeContents({:b})", self.bits)
3316 pub fn type_interior_is_unsafe<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> bool {
3317 type_contents(cx, ty).interior_unsafe()
3320 pub fn type_contents<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> TypeContents {
3321 return memoized(&cx.tc_cache, ty, |ty| {
3322 tc_ty(cx, ty, &mut FnvHashMap())
3325 fn tc_ty<'tcx>(cx: &ctxt<'tcx>,
3327 cache: &mut FnvHashMap<Ty<'tcx>, TypeContents>) -> TypeContents
3329 // Subtle: Note that we are *not* using cx.tc_cache here but rather a
3330 // private cache for this walk. This is needed in the case of cyclic
3333 // struct List { next: Box<Option<List>>, ... }
3335 // When computing the type contents of such a type, we wind up deeply
3336 // recursing as we go. So when we encounter the recursive reference
3337 // to List, we temporarily use TC::None as its contents. Later we'll
3338 // patch up the cache with the correct value, once we've computed it
3339 // (this is basically a co-inductive process, if that helps). So in
3340 // the end we'll compute TC::OwnsOwned, in this case.
3342 // The problem is, as we are doing the computation, we will also
3343 // compute an *intermediate* contents for, e.g., Option<List> of
3344 // TC::None. This is ok during the computation of List itself, but if
3345 // we stored this intermediate value into cx.tc_cache, then later
3346 // requests for the contents of Option<List> would also yield TC::None
3347 // which is incorrect. This value was computed based on the crutch
3348 // value for the type contents of list. The correct value is
3349 // TC::OwnsOwned. This manifested as issue #4821.
3350 match cache.get(&ty) {
3351 Some(tc) => { return *tc; }
3354 match cx.tc_cache.borrow().get(&ty) { // Must check both caches!
3355 Some(tc) => { return *tc; }
3358 cache.insert(ty, TC::None);
3360 let result = match ty.sty {
3361 // uint and int are ffi-unsafe
3362 ty_uint(ast::TyUs(_)) | ty_int(ast::TyIs(_)) => {
3363 TC::ReachesFfiUnsafe
3366 // Scalar and unique types are sendable, and durable
3367 ty_infer(ty::FreshIntTy(_)) |
3368 ty_bool | ty_int(_) | ty_uint(_) | ty_float(_) |
3369 ty_bare_fn(..) | ty::ty_char => {
3374 TC::ReachesFfiUnsafe | match typ.sty {
3375 ty_str => TC::OwnsOwned,
3376 _ => tc_ty(cx, typ, cache).owned_pointer(),
3380 ty_trait(box TyTrait { ref bounds, .. }) => {
3381 object_contents(bounds) | TC::ReachesFfiUnsafe | TC::Nonsized
3385 tc_ty(cx, mt.ty, cache).unsafe_pointer()
3388 ty_rptr(r, ref mt) => {
3389 TC::ReachesFfiUnsafe | match mt.ty.sty {
3390 ty_str => borrowed_contents(*r, ast::MutImmutable),
3391 ty_vec(..) => tc_ty(cx, mt.ty, cache).reference(borrowed_contents(*r,
3393 _ => tc_ty(cx, mt.ty, cache).reference(borrowed_contents(*r, mt.mutbl)),
3397 ty_vec(ty, Some(_)) => {
3398 tc_ty(cx, ty, cache)
3401 ty_vec(ty, None) => {
3402 tc_ty(cx, ty, cache) | TC::Nonsized
3404 ty_str => TC::Nonsized,
3406 ty_struct(did, substs) => {
3407 let flds = struct_fields(cx, did, substs);
3409 TypeContents::union(&flds[],
3410 |f| tc_mt(cx, f.mt, cache));
3412 if !lookup_repr_hints(cx, did).contains(&attr::ReprExtern) {
3413 res = res | TC::ReachesFfiUnsafe;
3416 if ty::has_dtor(cx, did) {
3417 res = res | TC::OwnsDtor;
3419 apply_lang_items(cx, did, res)
3422 ty_unboxed_closure(did, r, substs) => {
3423 // FIXME(#14449): `borrowed_contents` below assumes `&mut`
3425 let param_env = ty::empty_parameter_environment(cx);
3426 let upvars = unboxed_closure_upvars(¶m_env, did, substs).unwrap();
3427 TypeContents::union(upvars.as_slice(),
3428 |f| tc_ty(cx, f.ty, cache))
3429 | borrowed_contents(*r, MutMutable)
3432 ty_tup(ref tys) => {
3433 TypeContents::union(&tys[],
3434 |ty| tc_ty(cx, *ty, cache))
3437 ty_enum(did, substs) => {
3438 let variants = substd_enum_variants(cx, did, substs);
3440 TypeContents::union(&variants[], |variant| {
3441 TypeContents::union(&variant.args[],
3443 tc_ty(cx, *arg_ty, cache)
3447 if ty::has_dtor(cx, did) {
3448 res = res | TC::OwnsDtor;
3451 if variants.len() != 0 {
3452 let repr_hints = lookup_repr_hints(cx, did);
3453 if repr_hints.len() > 1 {
3454 // this is an error later on, but this type isn't safe
3455 res = res | TC::ReachesFfiUnsafe;
3458 match repr_hints.get(0) {
3459 Some(h) => if !h.is_ffi_safe() {
3460 res = res | TC::ReachesFfiUnsafe;
3464 res = res | TC::ReachesFfiUnsafe;
3466 // We allow ReprAny enums if they are eligible for
3467 // the nullable pointer optimization and the
3468 // contained type is an `extern fn`
3470 if variants.len() == 2 {
3471 let mut data_idx = 0;
3473 if variants[0].args.len() == 0 {
3477 if variants[data_idx].args.len() == 1 {
3478 match variants[data_idx].args[0].sty {
3479 ty_bare_fn(..) => { res = res - TC::ReachesFfiUnsafe; }
3489 apply_lang_items(cx, did, res)
3498 let result = tc_ty(cx, ty, cache);
3499 assert!(!result.is_sized(cx));
3500 result.unsafe_pointer() | TC::Nonsized
3505 cx.sess.bug("asked to compute contents of error type");
3509 cache.insert(ty, result);
3513 fn tc_mt<'tcx>(cx: &ctxt<'tcx>,
3515 cache: &mut FnvHashMap<Ty<'tcx>, TypeContents>) -> TypeContents
3517 let mc = TC::ReachesMutable.when(mt.mutbl == MutMutable);
3518 mc | tc_ty(cx, mt.ty, cache)
3521 fn apply_lang_items(cx: &ctxt, did: ast::DefId, tc: TypeContents)
3523 if Some(did) == cx.lang_items.managed_bound() {
3525 } else if Some(did) == cx.lang_items.unsafe_type() {
3526 tc | TC::InteriorUnsafe
3532 /// Type contents due to containing a reference with the region `region` and borrow kind `bk`
3533 fn borrowed_contents(region: ty::Region,
3534 mutbl: ast::Mutability)
3536 let b = match mutbl {
3537 ast::MutMutable => TC::ReachesMutable,
3538 ast::MutImmutable => TC::None,
3540 b | (TC::ReachesBorrowed).when(region != ty::ReStatic)
3543 fn object_contents(bounds: &ExistentialBounds) -> TypeContents {
3544 // These are the type contents of the (opaque) interior. We
3545 // make no assumptions (other than that it cannot have an
3546 // in-scope type parameter within, which makes no sense).
3547 let mut tc = TC::All - TC::InteriorParam;
3548 for bound in bounds.builtin_bounds.iter() {
3549 tc = tc - match bound {
3550 BoundSync | BoundSend | BoundCopy => TC::None,
3551 BoundSized => TC::Nonsized,
3558 fn type_impls_bound<'a,'tcx>(param_env: &ParameterEnvironment<'a,'tcx>,
3559 cache: &RefCell<HashMap<Ty<'tcx>,bool>>,
3561 bound: ty::BuiltinBound,
3565 assert!(!ty::type_needs_infer(ty));
3567 if !type_has_params(ty) && !type_has_self(ty) {
3568 match cache.borrow().get(&ty) {
3571 debug!("type_impls_bound({}, {:?}) = {:?} (cached)",
3572 ty.repr(param_env.tcx),
3580 let infcx = infer::new_infer_ctxt(param_env.tcx);
3582 let is_impld = traits::type_known_to_meet_builtin_bound(&infcx, param_env, ty, bound, span);
3584 debug!("type_impls_bound({}, {:?}) = {:?}",
3585 ty.repr(param_env.tcx),
3589 if !type_has_params(ty) && !type_has_self(ty) {
3590 let old_value = cache.borrow_mut().insert(ty, is_impld);
3591 assert!(old_value.is_none());
3597 pub fn type_moves_by_default<'a,'tcx>(param_env: &ParameterEnvironment<'a,'tcx>,
3602 let tcx = param_env.tcx;
3603 !type_impls_bound(param_env, &tcx.type_impls_copy_cache, ty, ty::BoundCopy, span)
3606 pub fn type_is_sized<'a,'tcx>(param_env: &ParameterEnvironment<'a,'tcx>,
3611 let tcx = param_env.tcx;
3612 type_impls_bound(param_env, &tcx.type_impls_sized_cache, ty, ty::BoundSized, span)
3615 pub fn is_ffi_safe<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> bool {
3616 !type_contents(cx, ty).intersects(TC::ReachesFfiUnsafe)
3619 // True if instantiating an instance of `r_ty` requires an instance of `r_ty`.
3620 pub fn is_instantiable<'tcx>(cx: &ctxt<'tcx>, r_ty: Ty<'tcx>) -> bool {
3621 fn type_requires<'tcx>(cx: &ctxt<'tcx>, seen: &mut Vec<DefId>,
3622 r_ty: Ty<'tcx>, ty: Ty<'tcx>) -> bool {
3623 debug!("type_requires({:?}, {:?})?",
3624 ::util::ppaux::ty_to_string(cx, r_ty),
3625 ::util::ppaux::ty_to_string(cx, ty));
3627 let r = r_ty == ty || subtypes_require(cx, seen, r_ty, ty);
3629 debug!("type_requires({:?}, {:?})? {:?}",
3630 ::util::ppaux::ty_to_string(cx, r_ty),
3631 ::util::ppaux::ty_to_string(cx, ty),
3636 fn subtypes_require<'tcx>(cx: &ctxt<'tcx>, seen: &mut Vec<DefId>,
3637 r_ty: Ty<'tcx>, ty: Ty<'tcx>) -> bool {
3638 debug!("subtypes_require({:?}, {:?})?",
3639 ::util::ppaux::ty_to_string(cx, r_ty),
3640 ::util::ppaux::ty_to_string(cx, ty));
3642 let r = match ty.sty {
3643 // fixed length vectors need special treatment compared to
3644 // normal vectors, since they don't necessarily have the
3645 // possibility to have length zero.
3646 ty_vec(_, Some(0)) => false, // don't need no contents
3647 ty_vec(ty, Some(_)) => type_requires(cx, seen, r_ty, ty),
3658 ty_vec(_, None) => {
3661 ty_uniq(typ) | ty_open(typ) => {
3662 type_requires(cx, seen, r_ty, typ)
3664 ty_rptr(_, ref mt) => {
3665 type_requires(cx, seen, r_ty, mt.ty)
3669 false // unsafe ptrs can always be NULL
3676 ty_struct(ref did, _) if seen.contains(did) => {
3680 ty_struct(did, substs) => {
3682 let fields = struct_fields(cx, did, substs);
3683 let r = fields.iter().any(|f| type_requires(cx, seen, r_ty, f.mt.ty));
3684 seen.pop().unwrap();
3690 ty_unboxed_closure(..) => {
3691 // this check is run on type definitions, so we don't expect to see
3692 // inference by-products or unboxed closure types
3693 cx.sess.bug(format!("requires check invoked on inapplicable type: {:?}",
3698 ts.iter().any(|ty| type_requires(cx, seen, r_ty, *ty))
3701 ty_enum(ref did, _) if seen.contains(did) => {
3705 ty_enum(did, substs) => {
3707 let vs = enum_variants(cx, did);
3708 let r = !vs.is_empty() && vs.iter().all(|variant| {
3709 variant.args.iter().any(|aty| {
3710 let sty = aty.subst(cx, substs);
3711 type_requires(cx, seen, r_ty, sty)
3714 seen.pop().unwrap();
3719 debug!("subtypes_require({:?}, {:?})? {:?}",
3720 ::util::ppaux::ty_to_string(cx, r_ty),
3721 ::util::ppaux::ty_to_string(cx, ty),
3727 let mut seen = Vec::new();
3728 !subtypes_require(cx, &mut seen, r_ty, r_ty)
3731 /// Describes whether a type is representable. For types that are not
3732 /// representable, 'SelfRecursive' and 'ContainsRecursive' are used to
3733 /// distinguish between types that are recursive with themselves and types that
3734 /// contain a different recursive type. These cases can therefore be treated
3735 /// differently when reporting errors.
3737 /// The ordering of the cases is significant. They are sorted so that cmp::max
3738 /// will keep the "more erroneous" of two values.
3739 #[derive(Copy, PartialOrd, Ord, Eq, PartialEq, Show)]
3740 pub enum Representability {
3746 /// Check whether a type is representable. This means it cannot contain unboxed
3747 /// structural recursion. This check is needed for structs and enums.
3748 pub fn is_type_representable<'tcx>(cx: &ctxt<'tcx>, sp: Span, ty: Ty<'tcx>)
3749 -> Representability {
3751 // Iterate until something non-representable is found
3752 fn find_nonrepresentable<'tcx, It: Iterator<Item=Ty<'tcx>>>(cx: &ctxt<'tcx>, sp: Span,
3753 seen: &mut Vec<Ty<'tcx>>,
3755 -> Representability {
3756 iter.fold(Representable,
3757 |r, ty| cmp::max(r, is_type_structurally_recursive(cx, sp, seen, ty)))
3760 fn are_inner_types_recursive<'tcx>(cx: &ctxt<'tcx>, sp: Span,
3761 seen: &mut Vec<Ty<'tcx>>, ty: Ty<'tcx>)
3762 -> Representability {
3765 find_nonrepresentable(cx, sp, seen, ts.iter().map(|ty| *ty))
3767 // Fixed-length vectors.
3768 // FIXME(#11924) Behavior undecided for zero-length vectors.
3769 ty_vec(ty, Some(_)) => {
3770 is_type_structurally_recursive(cx, sp, seen, ty)
3772 ty_struct(did, substs) => {
3773 let fields = struct_fields(cx, did, substs);
3774 find_nonrepresentable(cx, sp, seen, fields.iter().map(|f| f.mt.ty))
3776 ty_enum(did, substs) => {
3777 let vs = enum_variants(cx, did);
3778 let iter = vs.iter()
3779 .flat_map(|variant| { variant.args.iter() })
3780 .map(|aty| { aty.subst_spanned(cx, substs, Some(sp)) });
3782 find_nonrepresentable(cx, sp, seen, iter)
3784 ty_unboxed_closure(..) => {
3785 // this check is run on type definitions, so we don't expect to see
3786 // unboxed closure types
3787 cx.sess.bug(format!("requires check invoked on inapplicable type: {:?}",
3794 fn same_struct_or_enum_def_id(ty: Ty, did: DefId) -> bool {
3796 ty_struct(ty_did, _) | ty_enum(ty_did, _) => {
3803 fn same_type<'tcx>(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
3804 match (&a.sty, &b.sty) {
3805 (&ty_struct(did_a, ref substs_a), &ty_struct(did_b, ref substs_b)) |
3806 (&ty_enum(did_a, ref substs_a), &ty_enum(did_b, ref substs_b)) => {
3811 let types_a = substs_a.types.get_slice(subst::TypeSpace);
3812 let types_b = substs_b.types.get_slice(subst::TypeSpace);
3814 let pairs = types_a.iter().zip(types_b.iter());
3816 pairs.all(|(&a, &b)| same_type(a, b))
3824 // Does the type `ty` directly (without indirection through a pointer)
3825 // contain any types on stack `seen`?
3826 fn is_type_structurally_recursive<'tcx>(cx: &ctxt<'tcx>, sp: Span,
3827 seen: &mut Vec<Ty<'tcx>>,
3828 ty: Ty<'tcx>) -> Representability {
3829 debug!("is_type_structurally_recursive: {:?}",
3830 ::util::ppaux::ty_to_string(cx, ty));
3833 ty_struct(did, _) | ty_enum(did, _) => {
3835 // Iterate through stack of previously seen types.
3836 let mut iter = seen.iter();
3838 // The first item in `seen` is the type we are actually curious about.
3839 // We want to return SelfRecursive if this type contains itself.
3840 // It is important that we DON'T take generic parameters into account
3841 // for this check, so that Bar<T> in this example counts as SelfRecursive:
3844 // struct Bar<T> { x: Bar<Foo> }
3847 Some(&seen_type) => {
3848 if same_struct_or_enum_def_id(seen_type, did) {
3849 debug!("SelfRecursive: {:?} contains {:?}",
3850 ::util::ppaux::ty_to_string(cx, seen_type),
3851 ::util::ppaux::ty_to_string(cx, ty));
3852 return SelfRecursive;
3858 // We also need to know whether the first item contains other types that
3859 // are structurally recursive. If we don't catch this case, we will recurse
3860 // infinitely for some inputs.
3862 // It is important that we DO take generic parameters into account here,
3863 // so that code like this is considered SelfRecursive, not ContainsRecursive:
3865 // struct Foo { Option<Option<Foo>> }
3867 for &seen_type in iter {
3868 if same_type(ty, seen_type) {
3869 debug!("ContainsRecursive: {:?} contains {:?}",
3870 ::util::ppaux::ty_to_string(cx, seen_type),
3871 ::util::ppaux::ty_to_string(cx, ty));
3872 return ContainsRecursive;
3877 // For structs and enums, track all previously seen types by pushing them
3878 // onto the 'seen' stack.
3880 let out = are_inner_types_recursive(cx, sp, seen, ty);
3885 // No need to push in other cases.
3886 are_inner_types_recursive(cx, sp, seen, ty)
3891 debug!("is_type_representable: {:?}",
3892 ::util::ppaux::ty_to_string(cx, ty));
3894 // To avoid a stack overflow when checking an enum variant or struct that
3895 // contains a different, structurally recursive type, maintain a stack
3896 // of seen types and check recursion for each of them (issues #3008, #3779).
3897 let mut seen: Vec<Ty> = Vec::new();
3898 let r = is_type_structurally_recursive(cx, sp, &mut seen, ty);
3899 debug!("is_type_representable: {:?} is {:?}",
3900 ::util::ppaux::ty_to_string(cx, ty), r);
3904 pub fn type_is_trait(ty: Ty) -> bool {
3905 type_trait_info(ty).is_some()
3908 pub fn type_trait_info<'tcx>(ty: Ty<'tcx>) -> Option<&'tcx TyTrait<'tcx>> {
3910 ty_uniq(ty) | ty_rptr(_, mt { ty, ..}) | ty_ptr(mt { ty, ..}) => match ty.sty {
3911 ty_trait(ref t) => Some(&**t),
3914 ty_trait(ref t) => Some(&**t),
3919 pub fn type_is_integral(ty: Ty) -> bool {
3921 ty_infer(IntVar(_)) | ty_int(_) | ty_uint(_) => true,
3926 pub fn type_is_fresh(ty: Ty) -> bool {
3928 ty_infer(FreshTy(_)) => true,
3929 ty_infer(FreshIntTy(_)) => true,
3934 pub fn type_is_uint(ty: Ty) -> bool {
3936 ty_infer(IntVar(_)) | ty_uint(ast::TyUs(_)) => true,
3941 pub fn type_is_char(ty: Ty) -> bool {
3948 pub fn type_is_bare_fn(ty: Ty) -> bool {
3950 ty_bare_fn(..) => true,
3955 pub fn type_is_bare_fn_item(ty: Ty) -> bool {
3957 ty_bare_fn(Some(_), _) => true,
3962 pub fn type_is_fp(ty: Ty) -> bool {
3964 ty_infer(FloatVar(_)) | ty_float(_) => true,
3969 pub fn type_is_numeric(ty: Ty) -> bool {
3970 return type_is_integral(ty) || type_is_fp(ty);
3973 pub fn type_is_signed(ty: Ty) -> bool {
3980 pub fn type_is_machine(ty: Ty) -> bool {
3982 ty_int(ast::TyIs(_)) | ty_uint(ast::TyUs(_)) => false,
3983 ty_int(..) | ty_uint(..) | ty_float(..) => true,
3988 // Whether a type is enum like, that is an enum type with only nullary
3990 pub fn type_is_c_like_enum(cx: &ctxt, ty: Ty) -> bool {
3992 ty_enum(did, _) => {
3993 let variants = enum_variants(cx, did);
3994 if variants.len() == 0 {
3997 variants.iter().all(|v| v.args.len() == 0)
4004 // Returns the type and mutability of *ty.
4006 // The parameter `explicit` indicates if this is an *explicit* dereference.
4007 // Some types---notably unsafe ptrs---can only be dereferenced explicitly.
4008 pub fn deref<'tcx>(ty: Ty<'tcx>, explicit: bool) -> Option<mt<'tcx>> {
4013 mutbl: ast::MutImmutable,
4016 ty_rptr(_, mt) => Some(mt),
4017 ty_ptr(mt) if explicit => Some(mt),
4022 pub fn close_type<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
4024 ty_open(ty) => mk_rptr(cx, cx.mk_region(ReStatic), mt {ty: ty, mutbl:ast::MutImmutable}),
4025 _ => cx.sess.bug(&format!("Trying to close a non-open type {}",
4026 ty_to_string(cx, ty))[])
4030 pub fn type_content<'tcx>(ty: Ty<'tcx>) -> Ty<'tcx> {
4033 ty_rptr(_, mt) |ty_ptr(mt) => mt.ty,
4038 // Extract the unsized type in an open type (or just return ty if it is not open).
4039 pub fn unopen_type<'tcx>(ty: Ty<'tcx>) -> Ty<'tcx> {
4046 // Returns the type of ty[i]
4047 pub fn index<'tcx>(ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
4049 ty_vec(ty, _) => Some(ty),
4054 // Returns the type of elements contained within an 'array-like' type.
4055 // This is exactly the same as the above, except it supports strings,
4056 // which can't actually be indexed.
4057 pub fn array_element_ty<'tcx>(tcx: &ctxt<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
4059 ty_vec(ty, _) => Some(ty),
4060 ty_str => Some(tcx.types.u8),
4065 /// Returns the type of element at index `i` in tuple or tuple-like type `t`.
4066 /// For an enum `t`, `variant` is None only if `t` is a univariant enum.
4067 pub fn positional_element_ty<'tcx>(cx: &ctxt<'tcx>,
4070 variant: Option<ast::DefId>) -> Option<Ty<'tcx>> {
4072 match (&ty.sty, variant) {
4073 (&ty_tup(ref v), None) => v.get(i).map(|&t| t),
4076 (&ty_struct(def_id, substs), None) => lookup_struct_fields(cx, def_id)
4078 .map(|&t|lookup_item_type(cx, t.id).ty.subst(cx, substs)),
4080 (&ty_enum(def_id, substs), Some(variant_def_id)) => {
4081 let variant_info = enum_variant_with_id(cx, def_id, variant_def_id);
4082 variant_info.args.get(i).map(|t|t.subst(cx, substs))
4085 (&ty_enum(def_id, substs), None) => {
4086 assert!(enum_is_univariant(cx, def_id));
4087 let enum_variants = enum_variants(cx, def_id);
4088 let variant_info = &(*enum_variants)[0];
4089 variant_info.args.get(i).map(|t|t.subst(cx, substs))
4096 /// Returns the type of element at field `n` in struct or struct-like type `t`.
4097 /// For an enum `t`, `variant` must be some def id.
4098 pub fn named_element_ty<'tcx>(cx: &ctxt<'tcx>,
4101 variant: Option<ast::DefId>) -> Option<Ty<'tcx>> {
4103 match (&ty.sty, variant) {
4104 (&ty_struct(def_id, substs), None) => {
4105 let r = lookup_struct_fields(cx, def_id);
4106 r.iter().find(|f| f.name == n)
4107 .map(|&f| lookup_field_type(cx, def_id, f.id, substs))
4109 (&ty_enum(def_id, substs), Some(variant_def_id)) => {
4110 let variant_info = enum_variant_with_id(cx, def_id, variant_def_id);
4111 variant_info.arg_names.as_ref()
4112 .expect("must have struct enum variant if accessing a named fields")
4113 .iter().zip(variant_info.args.iter())
4114 .find(|&(ident, _)| ident.name == n)
4115 .map(|(_ident, arg_t)| arg_t.subst(cx, substs))
4121 pub fn node_id_to_trait_ref<'tcx>(cx: &ctxt<'tcx>, id: ast::NodeId)
4122 -> Rc<ty::TraitRef<'tcx>> {
4123 match cx.trait_refs.borrow().get(&id) {
4124 Some(ty) => ty.clone(),
4125 None => cx.sess.bug(
4126 &format!("node_id_to_trait_ref: no trait ref for node `{}`",
4127 cx.map.node_to_string(id))[])
4131 pub fn node_id_to_type<'tcx>(cx: &ctxt<'tcx>, id: ast::NodeId) -> Ty<'tcx> {
4132 match node_id_to_type_opt(cx, id) {
4134 None => cx.sess.bug(
4135 &format!("node_id_to_type: no type for node `{}`",
4136 cx.map.node_to_string(id))[])
4140 pub fn node_id_to_type_opt<'tcx>(cx: &ctxt<'tcx>, id: ast::NodeId) -> Option<Ty<'tcx>> {
4141 match cx.node_types.borrow().get(&id) {
4142 Some(&ty) => Some(ty),
4147 pub fn node_id_item_substs<'tcx>(cx: &ctxt<'tcx>, id: ast::NodeId) -> ItemSubsts<'tcx> {
4148 match cx.item_substs.borrow().get(&id) {
4149 None => ItemSubsts::empty(),
4150 Some(ts) => ts.clone(),
4154 pub fn fn_is_variadic(fty: Ty) -> bool {
4156 ty_bare_fn(_, ref f) => f.sig.0.variadic,
4158 panic!("fn_is_variadic() called on non-fn type: {:?}", s)
4163 pub fn ty_fn_sig<'tcx>(fty: Ty<'tcx>) -> &'tcx PolyFnSig<'tcx> {
4165 ty_bare_fn(_, ref f) => &f.sig,
4167 panic!("ty_fn_sig() called on non-fn type: {:?}", s)
4172 /// Returns the ABI of the given function.
4173 pub fn ty_fn_abi(fty: Ty) -> abi::Abi {
4175 ty_bare_fn(_, ref f) => f.abi,
4176 _ => panic!("ty_fn_abi() called on non-fn type"),
4180 // Type accessors for substructures of types
4181 pub fn ty_fn_args<'tcx>(fty: Ty<'tcx>) -> ty::Binder<Vec<Ty<'tcx>>> {
4182 ty_fn_sig(fty).inputs()
4185 pub fn ty_fn_ret<'tcx>(fty: Ty<'tcx>) -> Binder<FnOutput<'tcx>> {
4187 ty_bare_fn(_, ref f) => f.sig.output(),
4189 panic!("ty_fn_ret() called on non-fn type: {:?}", s)
4194 pub fn is_fn_ty(fty: Ty) -> bool {
4196 ty_bare_fn(..) => true,
4201 pub fn ty_region(tcx: &ctxt,
4205 ty_rptr(r, _) => *r,
4209 &format!("ty_region() invoked on an inappropriate ty: {:?}",
4215 pub fn free_region_from_def(free_id: ast::NodeId, def: &RegionParameterDef)
4218 ty::ReFree(ty::FreeRegion { scope: region::CodeExtent::from_node_id(free_id),
4219 bound_region: ty::BrNamed(def.def_id,
4223 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
4224 // doesn't provide type parameter substitutions.
4225 pub fn pat_ty<'tcx>(cx: &ctxt<'tcx>, pat: &ast::Pat) -> Ty<'tcx> {
4226 return node_id_to_type(cx, pat.id);
4230 // Returns the type of an expression as a monotype.
4232 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
4233 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
4234 // auto-ref. The type returned by this function does not consider such
4235 // adjustments. See `expr_ty_adjusted()` instead.
4237 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
4238 // ask for the type of "id" in "id(3)", it will return "fn(&int) -> int"
4239 // instead of "fn(ty) -> T with T = int".
4240 pub fn expr_ty<'tcx>(cx: &ctxt<'tcx>, expr: &ast::Expr) -> Ty<'tcx> {
4241 return node_id_to_type(cx, expr.id);
4244 pub fn expr_ty_opt<'tcx>(cx: &ctxt<'tcx>, expr: &ast::Expr) -> Option<Ty<'tcx>> {
4245 return node_id_to_type_opt(cx, expr.id);
4248 /// Returns the type of `expr`, considering any `AutoAdjustment`
4249 /// entry recorded for that expression.
4251 /// It would almost certainly be better to store the adjusted ty in with
4252 /// the `AutoAdjustment`, but I opted not to do this because it would
4253 /// require serializing and deserializing the type and, although that's not
4254 /// hard to do, I just hate that code so much I didn't want to touch it
4255 /// unless it was to fix it properly, which seemed a distraction from the
4256 /// task at hand! -nmatsakis
4257 pub fn expr_ty_adjusted<'tcx>(cx: &ctxt<'tcx>, expr: &ast::Expr) -> Ty<'tcx> {
4258 adjust_ty(cx, expr.span, expr.id, expr_ty(cx, expr),
4259 cx.adjustments.borrow().get(&expr.id),
4260 |method_call| cx.method_map.borrow().get(&method_call).map(|method| method.ty))
4263 pub fn expr_span(cx: &ctxt, id: NodeId) -> Span {
4264 match cx.map.find(id) {
4265 Some(ast_map::NodeExpr(e)) => {
4269 cx.sess.bug(&format!("Node id {} is not an expr: {:?}",
4274 cx.sess.bug(&format!("Node id {} is not present \
4275 in the node map", id)[]);
4280 pub fn local_var_name_str(cx: &ctxt, id: NodeId) -> InternedString {
4281 match cx.map.find(id) {
4282 Some(ast_map::NodeLocal(pat)) => {
4284 ast::PatIdent(_, ref path1, _) => {
4285 token::get_ident(path1.node)
4289 &format!("Variable id {} maps to {:?}, not local",
4296 cx.sess.bug(&format!("Variable id {} maps to {:?}, not local",
4303 /// See `expr_ty_adjusted`
4304 pub fn adjust_ty<'tcx, F>(cx: &ctxt<'tcx>,
4306 expr_id: ast::NodeId,
4307 unadjusted_ty: Ty<'tcx>,
4308 adjustment: Option<&AutoAdjustment<'tcx>>,
4311 F: FnMut(MethodCall) -> Option<Ty<'tcx>>,
4313 if let ty_err = unadjusted_ty.sty {
4314 return unadjusted_ty;
4317 return match adjustment {
4318 Some(adjustment) => {
4320 AdjustReifyFnPointer(_) => {
4321 match unadjusted_ty.sty {
4322 ty::ty_bare_fn(Some(_), b) => {
4323 ty::mk_bare_fn(cx, None, b)
4327 &format!("AdjustReifyFnPointer adjustment on non-fn-item: \
4334 AdjustDerefRef(ref adj) => {
4335 let mut adjusted_ty = unadjusted_ty;
4337 if !ty::type_is_error(adjusted_ty) {
4338 for i in range(0, adj.autoderefs) {
4339 let method_call = MethodCall::autoderef(expr_id, i);
4340 match method_type(method_call) {
4341 Some(method_ty) => {
4342 // overloaded deref operators have all late-bound
4343 // regions fully instantiated and coverge
4345 ty::assert_no_late_bound_regions(cx,
4346 &ty_fn_ret(method_ty));
4347 adjusted_ty = fn_ret.unwrap();
4351 match deref(adjusted_ty, true) {
4352 Some(mt) => { adjusted_ty = mt.ty; }
4356 &format!("the {}th autoderef failed: \
4359 ty_to_string(cx, adjusted_ty))
4366 adjust_ty_for_autoref(cx, span, adjusted_ty, adj.autoref.as_ref())
4370 None => unadjusted_ty
4374 pub fn adjust_ty_for_autoref<'tcx>(cx: &ctxt<'tcx>,
4377 autoref: Option<&AutoRef<'tcx>>)
4383 Some(&AutoPtr(r, m, ref a)) => {
4384 let adjusted_ty = match a {
4385 &Some(box ref a) => adjust_ty_for_autoref(cx, span, ty, Some(a)),
4388 mk_rptr(cx, cx.mk_region(r), mt {
4394 Some(&AutoUnsafe(m, ref a)) => {
4395 let adjusted_ty = match a {
4396 &Some(box ref a) => adjust_ty_for_autoref(cx, span, ty, Some(a)),
4399 mk_ptr(cx, mt {ty: adjusted_ty, mutbl: m})
4402 Some(&AutoUnsize(ref k)) => unsize_ty(cx, ty, k, span),
4404 Some(&AutoUnsizeUniq(ref k)) => ty::mk_uniq(cx, unsize_ty(cx, ty, k, span)),
4408 // Take a sized type and a sizing adjustment and produce an unsized version of
4410 pub fn unsize_ty<'tcx>(cx: &ctxt<'tcx>,
4412 kind: &UnsizeKind<'tcx>,
4416 &UnsizeLength(len) => match ty.sty {
4417 ty_vec(ty, Some(n)) => {
4419 mk_vec(cx, ty, None)
4421 _ => cx.sess.span_bug(span,
4422 &format!("UnsizeLength with bad sty: {:?}",
4423 ty_to_string(cx, ty))[])
4425 &UnsizeStruct(box ref k, tp_index) => match ty.sty {
4426 ty_struct(did, substs) => {
4427 let ty_substs = substs.types.get_slice(subst::TypeSpace);
4428 let new_ty = unsize_ty(cx, ty_substs[tp_index], k, span);
4429 let mut unsized_substs = substs.clone();
4430 unsized_substs.types.get_mut_slice(subst::TypeSpace)[tp_index] = new_ty;
4431 mk_struct(cx, did, cx.mk_substs(unsized_substs))
4433 _ => cx.sess.span_bug(span,
4434 &format!("UnsizeStruct with bad sty: {:?}",
4435 ty_to_string(cx, ty))[])
4437 &UnsizeVtable(TyTrait { ref principal, ref bounds }, _) => {
4438 mk_trait(cx, principal.clone(), bounds.clone())
4443 pub fn resolve_expr(tcx: &ctxt, expr: &ast::Expr) -> def::Def {
4444 match tcx.def_map.borrow().get(&expr.id) {
4447 tcx.sess.span_bug(expr.span, &format!(
4448 "no def-map entry for expr {}", expr.id)[]);
4453 pub fn expr_is_lval(tcx: &ctxt, e: &ast::Expr) -> bool {
4454 match expr_kind(tcx, e) {
4456 RvalueDpsExpr | RvalueDatumExpr | RvalueStmtExpr => false
4460 /// We categorize expressions into three kinds. The distinction between
4461 /// lvalue/rvalue is fundamental to the language. The distinction between the
4462 /// two kinds of rvalues is an artifact of trans which reflects how we will
4463 /// generate code for that kind of expression. See trans/expr.rs for more
4473 pub fn expr_kind(tcx: &ctxt, expr: &ast::Expr) -> ExprKind {
4474 if tcx.method_map.borrow().contains_key(&MethodCall::expr(expr.id)) {
4475 // Overloaded operations are generally calls, and hence they are
4476 // generated via DPS, but there are a few exceptions:
4477 return match expr.node {
4478 // `a += b` has a unit result.
4479 ast::ExprAssignOp(..) => RvalueStmtExpr,
4481 // the deref method invoked for `*a` always yields an `&T`
4482 ast::ExprUnary(ast::UnDeref, _) => LvalueExpr,
4484 // the index method invoked for `a[i]` always yields an `&T`
4485 ast::ExprIndex(..) => LvalueExpr,
4487 // `for` loops are statements
4488 ast::ExprForLoop(..) => RvalueStmtExpr,
4490 // in the general case, result could be any type, use DPS
4496 ast::ExprPath(_) | ast::ExprQPath(_) => {
4497 match resolve_expr(tcx, expr) {
4498 def::DefVariant(tid, vid, _) => {
4499 let variant_info = enum_variant_with_id(tcx, tid, vid);
4500 if variant_info.args.len() > 0u {
4509 def::DefStruct(_) => {
4510 match tcx.node_types.borrow().get(&expr.id) {
4511 Some(ty) => match ty.sty {
4512 ty_bare_fn(..) => RvalueDatumExpr,
4515 // See ExprCast below for why types might be missing.
4516 None => RvalueDatumExpr
4520 // Special case: A unit like struct's constructor must be called without () at the
4521 // end (like `UnitStruct`) which means this is an ExprPath to a DefFn. But in case
4522 // of unit structs this is should not be interpreted as function pointer but as
4523 // call to the constructor.
4524 def::DefFn(_, true) => RvalueDpsExpr,
4526 // Fn pointers are just scalar values.
4527 def::DefFn(..) | def::DefStaticMethod(..) | def::DefMethod(..) => RvalueDatumExpr,
4529 // Note: there is actually a good case to be made that
4530 // DefArg's, particularly those of immediate type, ought to
4531 // considered rvalues.
4532 def::DefStatic(..) |
4534 def::DefLocal(..) => LvalueExpr,
4536 def::DefConst(..) => RvalueDatumExpr,
4541 &format!("uncategorized def for expr {}: {:?}",
4548 ast::ExprUnary(ast::UnDeref, _) |
4549 ast::ExprField(..) |
4550 ast::ExprTupField(..) |
4551 ast::ExprIndex(..) => {
4556 ast::ExprMethodCall(..) |
4557 ast::ExprStruct(..) |
4558 ast::ExprRange(..) |
4561 ast::ExprMatch(..) |
4562 ast::ExprClosure(..) |
4563 ast::ExprBlock(..) |
4564 ast::ExprRepeat(..) |
4565 ast::ExprVec(..) => {
4569 ast::ExprIfLet(..) => {
4570 tcx.sess.span_bug(expr.span, "non-desugared ExprIfLet");
4572 ast::ExprWhileLet(..) => {
4573 tcx.sess.span_bug(expr.span, "non-desugared ExprWhileLet");
4576 ast::ExprLit(ref lit) if lit_is_str(&**lit) => {
4580 ast::ExprCast(..) => {
4581 match tcx.node_types.borrow().get(&expr.id) {
4583 if type_is_trait(ty) {
4590 // Technically, it should not happen that the expr is not
4591 // present within the table. However, it DOES happen
4592 // during type check, because the final types from the
4593 // expressions are not yet recorded in the tcx. At that
4594 // time, though, we are only interested in knowing lvalue
4595 // vs rvalue. It would be better to base this decision on
4596 // the AST type in cast node---but (at the time of this
4597 // writing) it's not easy to distinguish casts to traits
4598 // from other casts based on the AST. This should be
4599 // easier in the future, when casts to traits
4600 // would like @Foo, Box<Foo>, or &Foo.
4606 ast::ExprBreak(..) |
4607 ast::ExprAgain(..) |
4609 ast::ExprWhile(..) |
4611 ast::ExprAssign(..) |
4612 ast::ExprInlineAsm(..) |
4613 ast::ExprAssignOp(..) |
4614 ast::ExprForLoop(..) => {
4618 ast::ExprLit(_) | // Note: LitStr is carved out above
4619 ast::ExprUnary(..) |
4620 ast::ExprBox(None, _) |
4621 ast::ExprAddrOf(..) |
4622 ast::ExprBinary(..) => {
4626 ast::ExprBox(Some(ref place), _) => {
4627 // Special case `Box<T>` for now:
4628 let definition = match tcx.def_map.borrow().get(&place.id) {
4630 None => panic!("no def for place"),
4632 let def_id = definition.def_id();
4633 if tcx.lang_items.exchange_heap() == Some(def_id) {
4640 ast::ExprParen(ref e) => expr_kind(tcx, &**e),
4642 ast::ExprMac(..) => {
4645 "macro expression remains after expansion");
4650 pub fn stmt_node_id(s: &ast::Stmt) -> ast::NodeId {
4652 ast::StmtDecl(_, id) | StmtExpr(_, id) | StmtSemi(_, id) => {
4655 ast::StmtMac(..) => panic!("unexpanded macro in trans")
4659 pub fn field_idx_strict(tcx: &ctxt, name: ast::Name, fields: &[field])
4662 for f in fields.iter() { if f.name == name { return i; } i += 1u; }
4663 tcx.sess.bug(&format!(
4664 "no field named `{}` found in the list of fields `{:?}`",
4665 token::get_name(name),
4667 .map(|f| token::get_name(f.name).get().to_string())
4668 .collect::<Vec<String>>())[]);
4671 pub fn impl_or_trait_item_idx(id: ast::Name, trait_items: &[ImplOrTraitItem])
4673 trait_items.iter().position(|m| m.name() == id)
4676 pub fn ty_sort_string<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> String {
4678 ty_bool | ty_char | ty_int(_) |
4679 ty_uint(_) | ty_float(_) | ty_str => {
4680 ::util::ppaux::ty_to_string(cx, ty)
4682 ty_tup(ref tys) if tys.is_empty() => ::util::ppaux::ty_to_string(cx, ty),
4684 ty_enum(id, _) => format!("enum `{}`", item_path_str(cx, id)),
4685 ty_uniq(_) => "box".to_string(),
4686 ty_vec(_, Some(n)) => format!("array of {} elements", n),
4687 ty_vec(_, None) => "slice".to_string(),
4688 ty_ptr(_) => "*-ptr".to_string(),
4689 ty_rptr(_, _) => "&-ptr".to_string(),
4690 ty_bare_fn(Some(_), _) => format!("fn item"),
4691 ty_bare_fn(None, _) => "fn pointer".to_string(),
4692 ty_trait(ref inner) => {
4693 format!("trait {}", item_path_str(cx, inner.principal_def_id()))
4695 ty_struct(id, _) => {
4696 format!("struct `{}`", item_path_str(cx, id))
4698 ty_unboxed_closure(..) => "closure".to_string(),
4699 ty_tup(_) => "tuple".to_string(),
4700 ty_infer(TyVar(_)) => "inferred type".to_string(),
4701 ty_infer(IntVar(_)) => "integral variable".to_string(),
4702 ty_infer(FloatVar(_)) => "floating-point variable".to_string(),
4703 ty_infer(FreshTy(_)) => "skolemized type".to_string(),
4704 ty_infer(FreshIntTy(_)) => "skolemized integral type".to_string(),
4705 ty_projection(_) => "associated type".to_string(),
4706 ty_param(ref p) => {
4707 if p.space == subst::SelfSpace {
4710 "type parameter".to_string()
4713 ty_err => "type error".to_string(),
4714 ty_open(_) => "opened DST".to_string(),
4718 impl<'tcx> Repr<'tcx> for ty::type_err<'tcx> {
4719 fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
4720 ty::type_err_to_str(tcx, self)
4724 /// Explains the source of a type err in a short, human readable way. This is meant to be placed
4725 /// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()`
4726 /// afterwards to present additional details, particularly when it comes to lifetime-related
4728 pub fn type_err_to_str<'tcx>(cx: &ctxt<'tcx>, err: &type_err<'tcx>) -> String {
4730 terr_cyclic_ty => "cyclic type of infinite size".to_string(),
4731 terr_mismatch => "types differ".to_string(),
4732 terr_unsafety_mismatch(values) => {
4733 format!("expected {} fn, found {} fn",
4737 terr_abi_mismatch(values) => {
4738 format!("expected {} fn, found {} fn",
4742 terr_onceness_mismatch(values) => {
4743 format!("expected {} fn, found {} fn",
4747 terr_mutability => "values differ in mutability".to_string(),
4748 terr_box_mutability => {
4749 "boxed values differ in mutability".to_string()
4751 terr_vec_mutability => "vectors differ in mutability".to_string(),
4752 terr_ptr_mutability => "pointers differ in mutability".to_string(),
4753 terr_ref_mutability => "references differ in mutability".to_string(),
4754 terr_ty_param_size(values) => {
4755 format!("expected a type with {} type params, \
4756 found one with {} type params",
4760 terr_fixed_array_size(values) => {
4761 format!("expected an array with a fixed size of {} elements, \
4762 found one with {} elements",
4766 terr_tuple_size(values) => {
4767 format!("expected a tuple with {} elements, \
4768 found one with {} elements",
4773 "incorrect number of function parameters".to_string()
4775 terr_regions_does_not_outlive(..) => {
4776 "lifetime mismatch".to_string()
4778 terr_regions_not_same(..) => {
4779 "lifetimes are not the same".to_string()
4781 terr_regions_no_overlap(..) => {
4782 "lifetimes do not intersect".to_string()
4784 terr_regions_insufficiently_polymorphic(br, _) => {
4785 format!("expected bound lifetime parameter {}, \
4786 found concrete lifetime",
4787 bound_region_ptr_to_string(cx, br))
4789 terr_regions_overly_polymorphic(br, _) => {
4790 format!("expected concrete lifetime, \
4791 found bound lifetime parameter {}",
4792 bound_region_ptr_to_string(cx, br))
4794 terr_sorts(values) => {
4795 // A naive approach to making sure that we're not reporting silly errors such as:
4796 // (expected closure, found closure).
4797 let expected_str = ty_sort_string(cx, values.expected);
4798 let found_str = ty_sort_string(cx, values.found);
4799 if expected_str == found_str {
4800 format!("expected {}, found a different {}", expected_str, found_str)
4802 format!("expected {}, found {}", expected_str, found_str)
4805 terr_traits(values) => {
4806 format!("expected trait `{}`, found trait `{}`",
4807 item_path_str(cx, values.expected),
4808 item_path_str(cx, values.found))
4810 terr_builtin_bounds(values) => {
4811 if values.expected.is_empty() {
4812 format!("expected no bounds, found `{}`",
4813 values.found.user_string(cx))
4814 } else if values.found.is_empty() {
4815 format!("expected bounds `{}`, found no bounds",
4816 values.expected.user_string(cx))
4818 format!("expected bounds `{}`, found bounds `{}`",
4819 values.expected.user_string(cx),
4820 values.found.user_string(cx))
4823 terr_integer_as_char => {
4824 "expected an integral type, found `char`".to_string()
4826 terr_int_mismatch(ref values) => {
4827 format!("expected `{:?}`, found `{:?}`",
4831 terr_float_mismatch(ref values) => {
4832 format!("expected `{:?}`, found `{:?}`",
4836 terr_variadic_mismatch(ref values) => {
4837 format!("expected {} fn, found {} function",
4838 if values.expected { "variadic" } else { "non-variadic" },
4839 if values.found { "variadic" } else { "non-variadic" })
4841 terr_convergence_mismatch(ref values) => {
4842 format!("expected {} fn, found {} function",
4843 if values.expected { "converging" } else { "diverging" },
4844 if values.found { "converging" } else { "diverging" })
4846 terr_projection_name_mismatched(ref values) => {
4847 format!("expected {}, found {}",
4848 token::get_name(values.expected),
4849 token::get_name(values.found))
4851 terr_projection_bounds_length(ref values) => {
4852 format!("expected {} associated type bindings, found {}",
4859 pub fn note_and_explain_type_err(cx: &ctxt, err: &type_err) {
4861 terr_regions_does_not_outlive(subregion, superregion) => {
4862 note_and_explain_region(cx, "", subregion, "...");
4863 note_and_explain_region(cx, "...does not necessarily outlive ",
4866 terr_regions_not_same(region1, region2) => {
4867 note_and_explain_region(cx, "", region1, "...");
4868 note_and_explain_region(cx, "...is not the same lifetime as ",
4871 terr_regions_no_overlap(region1, region2) => {
4872 note_and_explain_region(cx, "", region1, "...");
4873 note_and_explain_region(cx, "...does not overlap ",
4876 terr_regions_insufficiently_polymorphic(_, conc_region) => {
4877 note_and_explain_region(cx,
4878 "concrete lifetime that was found is ",
4881 terr_regions_overly_polymorphic(_, ty::ReInfer(ty::ReVar(_))) => {
4882 // don't bother to print out the message below for
4883 // inference variables, it's not very illuminating.
4885 terr_regions_overly_polymorphic(_, conc_region) => {
4886 note_and_explain_region(cx,
4887 "expected concrete lifetime is ",
4894 pub fn provided_source(cx: &ctxt, id: ast::DefId) -> Option<ast::DefId> {
4895 cx.provided_method_sources.borrow().get(&id).map(|x| *x)
4898 pub fn provided_trait_methods<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
4899 -> Vec<Rc<Method<'tcx>>> {
4901 match cx.map.find(id.node) {
4902 Some(ast_map::NodeItem(item)) => {
4904 ItemTrait(_, _, _, ref ms) => {
4906 ast_util::split_trait_methods(&ms[]);
4909 match impl_or_trait_item(
4911 ast_util::local_def(m.id)) {
4912 MethodTraitItem(m) => m,
4913 TypeTraitItem(_) => {
4914 cx.sess.bug("provided_trait_methods(): \
4915 split_trait_methods() put \
4916 associated types in the \
4917 provided method bucket?!")
4923 cx.sess.bug(&format!("provided_trait_methods: `{:?}` is \
4930 cx.sess.bug(&format!("provided_trait_methods: `{:?}` is not a \
4936 csearch::get_provided_trait_methods(cx, id)
4940 /// Helper for looking things up in the various maps that are populated during
4941 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
4942 /// these share the pattern that if the id is local, it should have been loaded
4943 /// into the map by the `typeck::collect` phase. If the def-id is external,
4944 /// then we have to go consult the crate loading code (and cache the result for
4946 fn lookup_locally_or_in_crate_store<V, F>(descr: &str,
4948 map: &mut DefIdMap<V>,
4949 load_external: F) -> V where
4953 match map.get(&def_id).cloned() {
4954 Some(v) => { return v; }
4958 if def_id.krate == ast::LOCAL_CRATE {
4959 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
4961 let v = load_external();
4962 map.insert(def_id, v.clone());
4966 pub fn trait_item<'tcx>(cx: &ctxt<'tcx>, trait_did: ast::DefId, idx: uint)
4967 -> ImplOrTraitItem<'tcx> {
4968 let method_def_id = (*ty::trait_item_def_ids(cx, trait_did))[idx].def_id();
4969 impl_or_trait_item(cx, method_def_id)
4972 pub fn trait_items<'tcx>(cx: &ctxt<'tcx>, trait_did: ast::DefId)
4973 -> Rc<Vec<ImplOrTraitItem<'tcx>>> {
4974 let mut trait_items = cx.trait_items_cache.borrow_mut();
4975 match trait_items.get(&trait_did).cloned() {
4976 Some(trait_items) => trait_items,
4978 let def_ids = ty::trait_item_def_ids(cx, trait_did);
4979 let items: Rc<Vec<ImplOrTraitItem>> =
4980 Rc::new(def_ids.iter()
4981 .map(|d| impl_or_trait_item(cx, d.def_id()))
4983 trait_items.insert(trait_did, items.clone());
4989 pub fn trait_impl_polarity<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
4990 -> Option<ast::ImplPolarity> {
4991 if id.krate == ast::LOCAL_CRATE {
4992 match cx.map.find(id.node) {
4993 Some(ast_map::NodeItem(item)) => {
4995 ast::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
5002 csearch::get_impl_polarity(cx, id)
5006 pub fn impl_or_trait_item<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
5007 -> ImplOrTraitItem<'tcx> {
5008 lookup_locally_or_in_crate_store("impl_or_trait_items",
5010 &mut *cx.impl_or_trait_items
5013 csearch::get_impl_or_trait_item(cx, id)
5017 /// Returns true if the given ID refers to an associated type and false if it
5018 /// refers to anything else.
5019 pub fn is_associated_type(cx: &ctxt, id: ast::DefId) -> bool {
5020 memoized(&cx.associated_types, id, |id: ast::DefId| {
5021 if id.krate == ast::LOCAL_CRATE {
5022 match cx.impl_or_trait_items.borrow().get(&id) {
5025 TypeTraitItem(_) => true,
5026 MethodTraitItem(_) => false,
5032 csearch::is_associated_type(&cx.sess.cstore, id)
5037 /// Returns the parameter index that the given associated type corresponds to.
5038 pub fn associated_type_parameter_index(cx: &ctxt,
5039 trait_def: &TraitDef,
5040 associated_type_id: ast::DefId)
5042 for type_parameter_def in trait_def.generics.types.iter() {
5043 if type_parameter_def.def_id == associated_type_id {
5044 return type_parameter_def.index as uint
5047 cx.sess.bug("couldn't find associated type parameter index")
5050 #[derive(Copy, PartialEq, Eq)]
5051 pub struct AssociatedTypeInfo {
5052 pub def_id: ast::DefId,
5054 pub name: ast::Name,
5057 impl PartialOrd for AssociatedTypeInfo {
5058 fn partial_cmp(&self, other: &AssociatedTypeInfo) -> Option<Ordering> {
5059 Some(self.index.cmp(&other.index))
5063 impl Ord for AssociatedTypeInfo {
5064 fn cmp(&self, other: &AssociatedTypeInfo) -> Ordering {
5065 self.index.cmp(&other.index)
5069 pub fn trait_item_def_ids(cx: &ctxt, id: ast::DefId)
5070 -> Rc<Vec<ImplOrTraitItemId>> {
5071 lookup_locally_or_in_crate_store("trait_item_def_ids",
5073 &mut *cx.trait_item_def_ids.borrow_mut(),
5075 Rc::new(csearch::get_trait_item_def_ids(&cx.sess.cstore, id))
5079 pub fn impl_trait_ref<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
5080 -> Option<Rc<TraitRef<'tcx>>> {
5081 memoized(&cx.impl_trait_cache, id, |id: ast::DefId| {
5082 if id.krate == ast::LOCAL_CRATE {
5083 debug!("(impl_trait_ref) searching for trait impl {:?}", id);
5084 match cx.map.find(id.node) {
5085 Some(ast_map::NodeItem(item)) => {
5087 ast::ItemImpl(_, _, _, ref opt_trait, _, _) => {
5090 let trait_ref = ty::node_id_to_trait_ref(cx, t.ref_id);
5102 csearch::get_impl_trait(cx, id)
5107 pub fn trait_ref_to_def_id(tcx: &ctxt, tr: &ast::TraitRef) -> ast::DefId {
5108 let def = *tcx.def_map.borrow()
5110 .expect("no def-map entry for trait");
5114 pub fn try_add_builtin_trait(
5116 trait_def_id: ast::DefId,
5117 builtin_bounds: &mut EnumSet<BuiltinBound>)
5120 //! Checks whether `trait_ref` refers to one of the builtin
5121 //! traits, like `Send`, and adds the corresponding
5122 //! bound to the set `builtin_bounds` if so. Returns true if `trait_ref`
5123 //! is a builtin trait.
5125 match tcx.lang_items.to_builtin_kind(trait_def_id) {
5126 Some(bound) => { builtin_bounds.insert(bound); true }
5131 pub fn ty_to_def_id(ty: Ty) -> Option<ast::DefId> {
5134 Some(tt.principal_def_id()),
5137 ty_unboxed_closure(id, _, _) =>
5146 pub struct VariantInfo<'tcx> {
5147 pub args: Vec<Ty<'tcx>>,
5148 pub arg_names: Option<Vec<ast::Ident>>,
5149 pub ctor_ty: Option<Ty<'tcx>>,
5150 pub name: ast::Name,
5156 impl<'tcx> VariantInfo<'tcx> {
5158 /// Creates a new VariantInfo from the corresponding ast representation.
5160 /// Does not do any caching of the value in the type context.
5161 pub fn from_ast_variant(cx: &ctxt<'tcx>,
5162 ast_variant: &ast::Variant,
5163 discriminant: Disr) -> VariantInfo<'tcx> {
5164 let ctor_ty = node_id_to_type(cx, ast_variant.node.id);
5166 match ast_variant.node.kind {
5167 ast::TupleVariantKind(ref args) => {
5168 let arg_tys = if args.len() > 0 {
5169 // the regions in the argument types come from the
5170 // enum def'n, and hence will all be early bound
5171 ty::assert_no_late_bound_regions(cx, &ty_fn_args(ctor_ty))
5176 return VariantInfo {
5179 ctor_ty: Some(ctor_ty),
5180 name: ast_variant.node.name.name,
5181 id: ast_util::local_def(ast_variant.node.id),
5182 disr_val: discriminant,
5183 vis: ast_variant.node.vis
5186 ast::StructVariantKind(ref struct_def) => {
5187 let fields: &[StructField] = &struct_def.fields[];
5189 assert!(fields.len() > 0);
5191 let arg_tys = struct_def.fields.iter()
5192 .map(|field| node_id_to_type(cx, field.node.id)).collect();
5193 let arg_names = fields.iter().map(|field| {
5194 match field.node.kind {
5195 NamedField(ident, _) => ident,
5196 UnnamedField(..) => cx.sess.bug(
5197 "enum_variants: all fields in struct must have a name")
5201 return VariantInfo {
5203 arg_names: Some(arg_names),
5205 name: ast_variant.node.name.name,
5206 id: ast_util::local_def(ast_variant.node.id),
5207 disr_val: discriminant,
5208 vis: ast_variant.node.vis
5215 pub fn substd_enum_variants<'tcx>(cx: &ctxt<'tcx>,
5217 substs: &Substs<'tcx>)
5218 -> Vec<Rc<VariantInfo<'tcx>>> {
5219 enum_variants(cx, id).iter().map(|variant_info| {
5220 let substd_args = variant_info.args.iter()
5221 .map(|aty| aty.subst(cx, substs)).collect::<Vec<_>>();
5223 let substd_ctor_ty = variant_info.ctor_ty.subst(cx, substs);
5225 Rc::new(VariantInfo {
5227 ctor_ty: substd_ctor_ty,
5228 ..(**variant_info).clone()
5233 pub fn item_path_str(cx: &ctxt, id: ast::DefId) -> String {
5234 with_path(cx, id, |path| ast_map::path_to_string(path)).to_string()
5240 TraitDtor(DefId, bool)
5244 pub fn is_present(&self) -> bool {
5246 TraitDtor(..) => true,
5251 pub fn has_drop_flag(&self) -> bool {
5254 &TraitDtor(_, flag) => flag
5259 /* If struct_id names a struct with a dtor, return Some(the dtor's id).
5260 Otherwise return none. */
5261 pub fn ty_dtor(cx: &ctxt, struct_id: DefId) -> DtorKind {
5262 match cx.destructor_for_type.borrow().get(&struct_id) {
5263 Some(&method_def_id) => {
5264 let flag = !has_attr(cx, struct_id, "unsafe_no_drop_flag");
5266 TraitDtor(method_def_id, flag)
5272 pub fn has_dtor(cx: &ctxt, struct_id: DefId) -> bool {
5273 cx.destructor_for_type.borrow().contains_key(&struct_id)
5276 pub fn with_path<T, F>(cx: &ctxt, id: ast::DefId, f: F) -> T where
5277 F: FnOnce(ast_map::PathElems) -> T,
5279 if id.krate == ast::LOCAL_CRATE {
5280 cx.map.with_path(id.node, f)
5282 f(ast_map::Values(csearch::get_item_path(cx, id).iter()).chain(None))
5286 pub fn enum_is_univariant(cx: &ctxt, id: ast::DefId) -> bool {
5287 enum_variants(cx, id).len() == 1
5290 pub fn type_is_empty(cx: &ctxt, ty: Ty) -> bool {
5292 ty_enum(did, _) => (*enum_variants(cx, did)).is_empty(),
5297 pub fn enum_variants<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
5298 -> Rc<Vec<Rc<VariantInfo<'tcx>>>> {
5299 memoized(&cx.enum_var_cache, id, |id: ast::DefId| {
5300 if ast::LOCAL_CRATE != id.krate {
5301 Rc::new(csearch::get_enum_variants(cx, id))
5304 Although both this code and check_enum_variants in typeck/check
5305 call eval_const_expr, it should never get called twice for the same
5306 expr, since check_enum_variants also updates the enum_var_cache
5308 match cx.map.get(id.node) {
5309 ast_map::NodeItem(ref item) => {
5311 ast::ItemEnum(ref enum_definition, _) => {
5312 let mut last_discriminant: Option<Disr> = None;
5313 Rc::new(enum_definition.variants.iter().map(|variant| {
5315 let mut discriminant = match last_discriminant {
5316 Some(val) => val + 1,
5317 None => INITIAL_DISCRIMINANT_VALUE
5320 match variant.node.disr_expr {
5322 match const_eval::eval_const_expr_partial(cx, &**e) {
5323 Ok(const_eval::const_int(val)) => {
5324 discriminant = val as Disr
5326 Ok(const_eval::const_uint(val)) => {
5327 discriminant = val as Disr
5332 "expected signed integer constant");
5337 &format!("expected constant: {}",
5344 last_discriminant = Some(discriminant);
5345 Rc::new(VariantInfo::from_ast_variant(cx, &**variant,
5350 cx.sess.bug("enum_variants: id not bound to an enum")
5354 _ => cx.sess.bug("enum_variants: id not bound to an enum")
5360 // Returns information about the enum variant with the given ID:
5361 pub fn enum_variant_with_id<'tcx>(cx: &ctxt<'tcx>,
5362 enum_id: ast::DefId,
5363 variant_id: ast::DefId)
5364 -> Rc<VariantInfo<'tcx>> {
5365 enum_variants(cx, enum_id).iter()
5366 .find(|variant| variant.id == variant_id)
5367 .expect("enum_variant_with_id(): no variant exists with that ID")
5372 // If the given item is in an external crate, looks up its type and adds it to
5373 // the type cache. Returns the type parameters and type.
5374 pub fn lookup_item_type<'tcx>(cx: &ctxt<'tcx>,
5376 -> TypeScheme<'tcx> {
5377 lookup_locally_or_in_crate_store(
5378 "tcache", did, &mut *cx.tcache.borrow_mut(),
5379 || csearch::get_type(cx, did))
5382 /// Given the did of a trait, returns its canonical trait ref.
5383 pub fn lookup_trait_def<'tcx>(cx: &ctxt<'tcx>, did: ast::DefId)
5384 -> Rc<ty::TraitDef<'tcx>> {
5385 memoized(&cx.trait_defs, did, |did: DefId| {
5386 assert!(did.krate != ast::LOCAL_CRATE);
5387 Rc::new(csearch::get_trait_def(cx, did))
5391 /// Given a reference to a trait, returns the "superbounds" declared
5392 /// on the trait, with appropriate substitutions applied. Basically,
5393 /// this applies a filter to the where clauses on the trait, returning
5394 /// those that have the form:
5396 /// Self : SuperTrait<...>
5398 pub fn predicates_for_trait_ref<'tcx>(tcx: &ctxt<'tcx>,
5399 trait_ref: &PolyTraitRef<'tcx>)
5400 -> Vec<ty::Predicate<'tcx>>
5402 let trait_def = lookup_trait_def(tcx, trait_ref.def_id());
5404 debug!("bounds_for_trait_ref(trait_def={:?}, trait_ref={:?})",
5405 trait_def.repr(tcx), trait_ref.repr(tcx));
5407 // The interaction between HRTB and supertraits is not entirely
5408 // obvious. Let me walk you (and myself) through an example.
5410 // Let's start with an easy case. Consider two traits:
5412 // trait Foo<'a> : Bar<'a,'a> { }
5413 // trait Bar<'b,'c> { }
5415 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
5416 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
5417 // knew that `Foo<'x>` (for any 'x) then we also know that
5418 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
5419 // normal substitution.
5421 // In terms of why this is sound, the idea is that whenever there
5422 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
5423 // holds. So if there is an impl of `T:Foo<'a>` that applies to
5424 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
5427 // Another example to be careful of is this:
5429 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
5430 // trait Bar1<'b,'c> { }
5432 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
5433 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
5434 // reason is similar to the previous example: any impl of
5435 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
5436 // basically we would want to collapse the bound lifetimes from
5437 // the input (`trait_ref`) and the supertraits.
5439 // To achieve this in practice is fairly straightforward. Let's
5440 // consider the more complicated scenario:
5442 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
5443 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
5444 // where both `'x` and `'b` would have a DB index of 1.
5445 // The substitution from the input trait-ref is therefore going to be
5446 // `'a => 'x` (where `'x` has a DB index of 1).
5447 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
5448 // early-bound parameter and `'b' is a late-bound parameter with a
5450 // - If we replace `'a` with `'x` from the input, it too will have
5451 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
5452 // just as we wanted.
5454 // There is only one catch. If we just apply the substitution `'a
5455 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
5456 // adjust the DB index because we substituting into a binder (it
5457 // tries to be so smart...) resulting in `for<'x> for<'b>
5458 // Bar1<'x,'b>` (we have no syntax for this, so use your
5459 // imagination). Basically the 'x will have DB index of 2 and 'b
5460 // will have DB index of 1. Not quite what we want. So we apply
5461 // the substitution to the *contents* of the trait reference,
5462 // rather than the trait reference itself (put another way, the
5463 // substitution code expects equal binding levels in the values
5464 // from the substitution and the value being substituted into, and
5465 // this trick achieves that).
5467 // Carefully avoid the binder introduced by each trait-ref by
5468 // substituting over the substs, not the trait-refs themselves,
5469 // thus achieving the "collapse" described in the big comment
5471 let trait_bounds: Vec<_> =
5472 trait_def.bounds.trait_bounds
5474 .map(|poly_trait_ref| ty::Binder(poly_trait_ref.0.subst(tcx, trait_ref.substs())))
5477 let projection_bounds: Vec<_> =
5478 trait_def.bounds.projection_bounds
5480 .map(|poly_proj| ty::Binder(poly_proj.0.subst(tcx, trait_ref.substs())))
5483 debug!("bounds_for_trait_ref: trait_bounds={} projection_bounds={}",
5484 trait_bounds.repr(tcx),
5485 projection_bounds.repr(tcx));
5487 // The region bounds and builtin bounds do not currently introduce
5488 // binders so we can just substitute in a straightforward way here.
5490 trait_def.bounds.region_bounds.subst(tcx, trait_ref.substs());
5491 let builtin_bounds =
5492 trait_def.bounds.builtin_bounds.subst(tcx, trait_ref.substs());
5494 let bounds = ty::ParamBounds {
5495 trait_bounds: trait_bounds,
5496 region_bounds: region_bounds,
5497 builtin_bounds: builtin_bounds,
5498 projection_bounds: projection_bounds,
5501 predicates(tcx, trait_ref.self_ty(), &bounds)
5504 pub fn predicates<'tcx>(
5507 bounds: &ParamBounds<'tcx>)
5508 -> Vec<Predicate<'tcx>>
5510 let mut vec = Vec::new();
5512 for builtin_bound in bounds.builtin_bounds.iter() {
5513 match traits::trait_ref_for_builtin_bound(tcx, builtin_bound, param_ty) {
5514 Ok(trait_ref) => { vec.push(trait_ref.as_predicate()); }
5515 Err(ErrorReported) => { }
5519 for ®ion_bound in bounds.region_bounds.iter() {
5520 // account for the binder being introduced below; no need to shift `param_ty`
5521 // because, at present at least, it can only refer to early-bound regions
5522 let region_bound = ty_fold::shift_region(region_bound, 1);
5523 vec.push(ty::Binder(ty::OutlivesPredicate(param_ty, region_bound)).as_predicate());
5526 for bound_trait_ref in bounds.trait_bounds.iter() {
5527 vec.push(bound_trait_ref.as_predicate());
5530 for projection in bounds.projection_bounds.iter() {
5531 vec.push(projection.as_predicate());
5537 /// Get the attributes of a definition.
5538 pub fn get_attrs<'tcx>(tcx: &'tcx ctxt, did: DefId)
5539 -> CowVec<'tcx, ast::Attribute> {
5541 let item = tcx.map.expect_item(did.node);
5542 Cow::Borrowed(&item.attrs[])
5544 Cow::Owned(csearch::get_item_attrs(&tcx.sess.cstore, did))
5548 /// Determine whether an item is annotated with an attribute
5549 pub fn has_attr(tcx: &ctxt, did: DefId, attr: &str) -> bool {
5550 get_attrs(tcx, did).iter().any(|item| item.check_name(attr))
5553 /// Determine whether an item is annotated with `#[repr(packed)]`
5554 pub fn lookup_packed(tcx: &ctxt, did: DefId) -> bool {
5555 lookup_repr_hints(tcx, did).contains(&attr::ReprPacked)
5558 /// Determine whether an item is annotated with `#[simd]`
5559 pub fn lookup_simd(tcx: &ctxt, did: DefId) -> bool {
5560 has_attr(tcx, did, "simd")
5563 /// Obtain the representation annotation for a struct definition.
5564 pub fn lookup_repr_hints(tcx: &ctxt, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
5565 memoized(&tcx.repr_hint_cache, did, |did: DefId| {
5566 Rc::new(if did.krate == LOCAL_CRATE {
5567 get_attrs(tcx, did).iter().flat_map(|meta| {
5568 attr::find_repr_attrs(tcx.sess.diagnostic(), meta).into_iter()
5571 csearch::get_repr_attrs(&tcx.sess.cstore, did)
5576 // Look up a field ID, whether or not it's local
5577 // Takes a list of type substs in case the struct is generic
5578 pub fn lookup_field_type<'tcx>(tcx: &ctxt<'tcx>,
5581 substs: &Substs<'tcx>)
5583 let ty = if id.krate == ast::LOCAL_CRATE {
5584 node_id_to_type(tcx, id.node)
5586 let mut tcache = tcx.tcache.borrow_mut();
5587 let pty = tcache.entry(id).get().unwrap_or_else(
5588 |vacant_entry| vacant_entry.insert(csearch::get_field_type(tcx, struct_id, id)));
5591 ty.subst(tcx, substs)
5594 // Look up the list of field names and IDs for a given struct.
5595 // Panics if the id is not bound to a struct.
5596 pub fn lookup_struct_fields(cx: &ctxt, did: ast::DefId) -> Vec<field_ty> {
5597 if did.krate == ast::LOCAL_CRATE {
5598 let struct_fields = cx.struct_fields.borrow();
5599 match struct_fields.get(&did) {
5600 Some(fields) => (**fields).clone(),
5603 &format!("ID not mapped to struct fields: {}",
5604 cx.map.node_to_string(did.node))[]);
5608 csearch::get_struct_fields(&cx.sess.cstore, did)
5612 pub fn is_tuple_struct(cx: &ctxt, did: ast::DefId) -> bool {
5613 let fields = lookup_struct_fields(cx, did);
5614 !fields.is_empty() && fields.iter().all(|f| f.name == token::special_names::unnamed_field)
5617 // Returns a list of fields corresponding to the struct's items. trans uses
5618 // this. Takes a list of substs with which to instantiate field types.
5619 pub fn struct_fields<'tcx>(cx: &ctxt<'tcx>, did: ast::DefId, substs: &Substs<'tcx>)
5620 -> Vec<field<'tcx>> {
5621 lookup_struct_fields(cx, did).iter().map(|f| {
5625 ty: lookup_field_type(cx, did, f.id, substs),
5632 // Returns a list of fields corresponding to the tuple's items. trans uses
5634 pub fn tup_fields<'tcx>(v: &[Ty<'tcx>]) -> Vec<field<'tcx>> {
5635 v.iter().enumerate().map(|(i, &f)| {
5637 name: token::intern(&i.to_string()[]),
5646 #[derive(Copy, Clone)]
5647 pub struct UnboxedClosureUpvar<'tcx> {
5653 // Returns a list of `UnboxedClosureUpvar`s for each upvar.
5654 pub fn unboxed_closure_upvars<'tcx>(typer: &mc::Typer<'tcx>,
5655 closure_id: ast::DefId,
5656 substs: &Substs<'tcx>)
5657 -> Option<Vec<UnboxedClosureUpvar<'tcx>>>
5659 // Presently an unboxed closure type cannot "escape" out of a
5660 // function, so we will only encounter ones that originated in the
5661 // local crate or were inlined into it along with some function.
5662 // This may change if abstract return types of some sort are
5664 assert!(closure_id.krate == ast::LOCAL_CRATE);
5665 let tcx = typer.tcx();
5666 let capture_mode = tcx.capture_modes.borrow()[closure_id.node].clone();
5667 match tcx.freevars.borrow().get(&closure_id.node) {
5668 None => Some(vec![]),
5669 Some(ref freevars) => {
5672 let freevar_def_id = freevar.def.def_id();
5673 let freevar_ty = match typer.node_ty(freevar_def_id.node) {
5675 Err(()) => { return None; }
5677 let freevar_ty = freevar_ty.subst(tcx, substs);
5679 match capture_mode {
5680 ast::CaptureByValue => {
5681 Some(UnboxedClosureUpvar { def: freevar.def,
5686 ast::CaptureByRef => {
5687 let upvar_id = ty::UpvarId {
5688 var_id: freevar_def_id.node,
5689 closure_expr_id: closure_id.node
5693 let freevar_ref_ty = match typer.upvar_borrow(upvar_id) {
5696 tcx.mk_region(borrow.region),
5699 mutbl: borrow.kind.to_mutbl_lossy(),
5703 // FIXME(#16640) we should really return None here;
5704 // but that requires better inference integration,
5705 // for now gin up something.
5709 Some(UnboxedClosureUpvar {
5722 pub fn is_binopable<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>, op: ast::BinOp) -> bool {
5723 #![allow(non_upper_case_globals)]
5724 static tycat_other: int = 0;
5725 static tycat_bool: int = 1;
5726 static tycat_char: int = 2;
5727 static tycat_int: int = 3;
5728 static tycat_float: int = 4;
5729 static tycat_raw_ptr: int = 6;
5731 static opcat_add: int = 0;
5732 static opcat_sub: int = 1;
5733 static opcat_mult: int = 2;
5734 static opcat_shift: int = 3;
5735 static opcat_rel: int = 4;
5736 static opcat_eq: int = 5;
5737 static opcat_bit: int = 6;
5738 static opcat_logic: int = 7;
5739 static opcat_mod: int = 8;
5741 fn opcat(op: ast::BinOp) -> int {
5743 ast::BiAdd => opcat_add,
5744 ast::BiSub => opcat_sub,
5745 ast::BiMul => opcat_mult,
5746 ast::BiDiv => opcat_mult,
5747 ast::BiRem => opcat_mod,
5748 ast::BiAnd => opcat_logic,
5749 ast::BiOr => opcat_logic,
5750 ast::BiBitXor => opcat_bit,
5751 ast::BiBitAnd => opcat_bit,
5752 ast::BiBitOr => opcat_bit,
5753 ast::BiShl => opcat_shift,
5754 ast::BiShr => opcat_shift,
5755 ast::BiEq => opcat_eq,
5756 ast::BiNe => opcat_eq,
5757 ast::BiLt => opcat_rel,
5758 ast::BiLe => opcat_rel,
5759 ast::BiGe => opcat_rel,
5760 ast::BiGt => opcat_rel
5764 fn tycat<'tcx>(cx: &ctxt<'tcx>, ty: Ty<'tcx>) -> int {
5765 if type_is_simd(cx, ty) {
5766 return tycat(cx, simd_type(cx, ty))
5769 ty_char => tycat_char,
5770 ty_bool => tycat_bool,
5771 ty_int(_) | ty_uint(_) | ty_infer(IntVar(_)) => tycat_int,
5772 ty_float(_) | ty_infer(FloatVar(_)) => tycat_float,
5773 ty_ptr(_) => tycat_raw_ptr,
5778 static t: bool = true;
5779 static f: bool = false;
5782 // +, -, *, shift, rel, ==, bit, logic, mod
5783 /*other*/ [f, f, f, f, f, f, f, f, f],
5784 /*bool*/ [f, f, f, f, t, t, t, t, f],
5785 /*char*/ [f, f, f, f, t, t, f, f, f],
5786 /*int*/ [t, t, t, t, t, t, t, f, t],
5787 /*float*/ [t, t, t, f, t, t, f, f, f],
5788 /*bot*/ [t, t, t, t, t, t, t, t, t],
5789 /*raw ptr*/ [f, f, f, f, t, t, f, f, f]];
5791 return tbl[tycat(cx, ty) as uint ][opcat(op) as uint];
5794 // Returns the repeat count for a repeating vector expression.
5795 pub fn eval_repeat_count(tcx: &ctxt, count_expr: &ast::Expr) -> uint {
5796 match const_eval::eval_const_expr_partial(tcx, count_expr) {
5798 let found = match val {
5799 const_eval::const_uint(count) => return count as uint,
5800 const_eval::const_int(count) if count >= 0 => return count as uint,
5801 const_eval::const_int(_) =>
5803 const_eval::const_float(_) =>
5805 const_eval::const_str(_) =>
5807 const_eval::const_bool(_) =>
5809 const_eval::const_binary(_) =>
5812 tcx.sess.span_err(count_expr.span, &format!(
5813 "expected positive integer for repeat count, found {}",
5817 let found = match count_expr.node {
5818 ast::ExprPath(ast::Path {
5822 }) if segments.len() == 1 =>
5825 "non-constant expression"
5827 tcx.sess.span_err(count_expr.span, &format!(
5828 "expected constant integer for repeat count, found {}",
5835 // Iterate over a type parameter's bounded traits and any supertraits
5836 // of those traits, ignoring kinds.
5837 // Here, the supertraits are the transitive closure of the supertrait
5838 // relation on the supertraits from each bounded trait's constraint
5840 pub fn each_bound_trait_and_supertraits<'tcx, F>(tcx: &ctxt<'tcx>,
5841 bounds: &[PolyTraitRef<'tcx>],
5844 F: FnMut(PolyTraitRef<'tcx>) -> bool,
5846 for bound_trait_ref in traits::transitive_bounds(tcx, bounds) {
5847 if !f(bound_trait_ref) {
5854 pub fn object_region_bounds<'tcx>(
5856 opt_principal: Option<&PolyTraitRef<'tcx>>, // None for closures
5857 others: BuiltinBounds)
5860 // Since we don't actually *know* the self type for an object,
5861 // this "open(err)" serves as a kind of dummy standin -- basically
5862 // a skolemized type.
5863 let open_ty = ty::mk_infer(tcx, FreshTy(0));
5865 let opt_trait_ref = opt_principal.map_or(Vec::new(), |principal| {
5866 // Note that we preserve the overall binding levels here.
5867 assert!(!open_ty.has_escaping_regions());
5868 let substs = tcx.mk_substs(principal.0.substs.with_self_ty(open_ty));
5869 vec!(ty::Binder(Rc::new(ty::TraitRef::new(principal.0.def_id, substs))))
5872 let param_bounds = ty::ParamBounds {
5873 region_bounds: Vec::new(),
5874 builtin_bounds: others,
5875 trait_bounds: opt_trait_ref,
5876 projection_bounds: Vec::new(), // not relevant to computing region bounds
5879 let predicates = ty::predicates(tcx, open_ty, ¶m_bounds);
5880 ty::required_region_bounds(tcx, open_ty, predicates)
5883 /// Given a set of predicates that apply to an object type, returns
5884 /// the region bounds that the (erased) `Self` type must
5885 /// outlive. Precisely *because* the `Self` type is erased, the
5886 /// parameter `erased_self_ty` must be supplied to indicate what type
5887 /// has been used to represent `Self` in the predicates
5888 /// themselves. This should really be a unique type; `FreshTy(0)` is a
5889 /// popular choice (see `object_region_bounds` above).
5891 /// Requires that trait definitions have been processed so that we can
5892 /// elaborate predicates and walk supertraits.
5893 pub fn required_region_bounds<'tcx>(tcx: &ctxt<'tcx>,
5894 erased_self_ty: Ty<'tcx>,
5895 predicates: Vec<ty::Predicate<'tcx>>)
5898 debug!("required_region_bounds(erased_self_ty={:?}, predicates={:?})",
5899 erased_self_ty.repr(tcx),
5900 predicates.repr(tcx));
5902 assert!(!erased_self_ty.has_escaping_regions());
5904 traits::elaborate_predicates(tcx, predicates)
5905 .filter_map(|predicate| {
5907 ty::Predicate::Projection(..) |
5908 ty::Predicate::Trait(..) |
5909 ty::Predicate::Equate(..) |
5910 ty::Predicate::RegionOutlives(..) => {
5913 ty::Predicate::TypeOutlives(ty::Binder(ty::OutlivesPredicate(t, r))) => {
5914 // Search for a bound of the form `erased_self_ty
5915 // : 'a`, but be wary of something like `for<'a>
5916 // erased_self_ty : 'a` (we interpret a
5917 // higher-ranked bound like that as 'static,
5918 // though at present the code in `fulfill.rs`
5919 // considers such bounds to be unsatisfiable, so
5920 // it's kind of a moot point since you could never
5921 // construct such an object, but this seems
5922 // correct even if that code changes).
5923 if t == erased_self_ty && !r.has_escaping_regions() {
5924 if r.has_escaping_regions() {
5938 pub fn get_tydesc_ty<'tcx>(tcx: &ctxt<'tcx>) -> Result<Ty<'tcx>, String> {
5939 tcx.lang_items.require(TyDescStructLangItem).map(|tydesc_lang_item| {
5940 tcx.intrinsic_defs.borrow().get(&tydesc_lang_item).cloned()
5941 .expect("Failed to resolve TyDesc")
5945 pub fn item_variances(tcx: &ctxt, item_id: ast::DefId) -> Rc<ItemVariances> {
5946 lookup_locally_or_in_crate_store(
5947 "item_variance_map", item_id, &mut *tcx.item_variance_map.borrow_mut(),
5948 || Rc::new(csearch::get_item_variances(&tcx.sess.cstore, item_id)))
5951 /// Records a trait-to-implementation mapping.
5952 pub fn record_trait_implementation(tcx: &ctxt,
5953 trait_def_id: DefId,
5954 impl_def_id: DefId) {
5956 match tcx.trait_impls.borrow().get(&trait_def_id) {
5957 Some(impls_for_trait) => {
5958 impls_for_trait.borrow_mut().push(impl_def_id);
5964 tcx.trait_impls.borrow_mut().insert(trait_def_id, Rc::new(RefCell::new(vec!(impl_def_id))));
5967 /// Populates the type context with all the implementations for the given type
5969 pub fn populate_implementations_for_type_if_necessary(tcx: &ctxt,
5970 type_id: ast::DefId) {
5971 if type_id.krate == LOCAL_CRATE {
5974 if tcx.populated_external_types.borrow().contains(&type_id) {
5978 debug!("populate_implementations_for_type_if_necessary: searching for {:?}", type_id);
5980 let mut inherent_impls = Vec::new();
5981 csearch::each_implementation_for_type(&tcx.sess.cstore, type_id,
5983 let impl_items = csearch::get_impl_items(&tcx.sess.cstore, impl_def_id);
5985 // Record the trait->implementation mappings, if applicable.
5986 let associated_traits = csearch::get_impl_trait(tcx, impl_def_id);
5987 for trait_ref in associated_traits.iter() {
5988 record_trait_implementation(tcx, trait_ref.def_id, impl_def_id);
5991 // For any methods that use a default implementation, add them to
5992 // the map. This is a bit unfortunate.
5993 for impl_item_def_id in impl_items.iter() {
5994 let method_def_id = impl_item_def_id.def_id();
5995 match impl_or_trait_item(tcx, method_def_id) {
5996 MethodTraitItem(method) => {
5997 for &source in method.provided_source.iter() {
5998 tcx.provided_method_sources
6000 .insert(method_def_id, source);
6003 TypeTraitItem(_) => {}
6007 // Store the implementation info.
6008 tcx.impl_items.borrow_mut().insert(impl_def_id, impl_items);
6010 // If this is an inherent implementation, record it.
6011 if associated_traits.is_none() {
6012 inherent_impls.push(impl_def_id);
6016 tcx.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
6017 tcx.populated_external_types.borrow_mut().insert(type_id);
6020 /// Populates the type context with all the implementations for the given
6021 /// trait if necessary.
6022 pub fn populate_implementations_for_trait_if_necessary(
6024 trait_id: ast::DefId) {
6025 if trait_id.krate == LOCAL_CRATE {
6028 if tcx.populated_external_traits.borrow().contains(&trait_id) {
6032 csearch::each_implementation_for_trait(&tcx.sess.cstore, trait_id,
6033 |implementation_def_id| {
6034 let impl_items = csearch::get_impl_items(&tcx.sess.cstore, implementation_def_id);
6036 // Record the trait->implementation mapping.
6037 record_trait_implementation(tcx, trait_id, implementation_def_id);
6039 // For any methods that use a default implementation, add them to
6040 // the map. This is a bit unfortunate.
6041 for impl_item_def_id in impl_items.iter() {
6042 let method_def_id = impl_item_def_id.def_id();
6043 match impl_or_trait_item(tcx, method_def_id) {
6044 MethodTraitItem(method) => {
6045 for &source in method.provided_source.iter() {
6046 tcx.provided_method_sources
6048 .insert(method_def_id, source);
6051 TypeTraitItem(_) => {}
6055 // Store the implementation info.
6056 tcx.impl_items.borrow_mut().insert(implementation_def_id, impl_items);
6059 tcx.populated_external_traits.borrow_mut().insert(trait_id);
6062 /// Given the def_id of an impl, return the def_id of the trait it implements.
6063 /// If it implements no trait, return `None`.
6064 pub fn trait_id_of_impl(tcx: &ctxt,
6066 -> Option<ast::DefId> {
6067 ty::impl_trait_ref(tcx, def_id).map(|tr| tr.def_id)
6070 /// If the given def ID describes a method belonging to an impl, return the
6071 /// ID of the impl that the method belongs to. Otherwise, return `None`.
6072 pub fn impl_of_method(tcx: &ctxt, def_id: ast::DefId)
6073 -> Option<ast::DefId> {
6074 if def_id.krate != LOCAL_CRATE {
6075 return match csearch::get_impl_or_trait_item(tcx,
6076 def_id).container() {
6077 TraitContainer(_) => None,
6078 ImplContainer(def_id) => Some(def_id),
6081 match tcx.impl_or_trait_items.borrow().get(&def_id).cloned() {
6082 Some(trait_item) => {
6083 match trait_item.container() {
6084 TraitContainer(_) => None,
6085 ImplContainer(def_id) => Some(def_id),
6092 /// If the given def ID describes an item belonging to a trait (either a
6093 /// default method or an implementation of a trait method), return the ID of
6094 /// the trait that the method belongs to. Otherwise, return `None`.
6095 pub fn trait_of_item(tcx: &ctxt, def_id: ast::DefId) -> Option<ast::DefId> {
6096 if def_id.krate != LOCAL_CRATE {
6097 return csearch::get_trait_of_item(&tcx.sess.cstore, def_id, tcx);
6099 match tcx.impl_or_trait_items.borrow().get(&def_id).cloned() {
6100 Some(impl_or_trait_item) => {
6101 match impl_or_trait_item.container() {
6102 TraitContainer(def_id) => Some(def_id),
6103 ImplContainer(def_id) => trait_id_of_impl(tcx, def_id),
6110 /// If the given def ID describes an item belonging to a trait, (either a
6111 /// default method or an implementation of a trait method), return the ID of
6112 /// the method inside trait definition (this means that if the given def ID
6113 /// is already that of the original trait method, then the return value is
6115 /// Otherwise, return `None`.
6116 pub fn trait_item_of_item(tcx: &ctxt, def_id: ast::DefId)
6117 -> Option<ImplOrTraitItemId> {
6118 let impl_item = match tcx.impl_or_trait_items.borrow().get(&def_id) {
6119 Some(m) => m.clone(),
6120 None => return None,
6122 let name = impl_item.name();
6123 match trait_of_item(tcx, def_id) {
6124 Some(trait_did) => {
6125 let trait_items = ty::trait_items(tcx, trait_did);
6127 .position(|m| m.name() == name)
6128 .map(|idx| ty::trait_item(tcx, trait_did, idx).id())
6134 /// Creates a hash of the type `Ty` which will be the same no matter what crate
6135 /// context it's calculated within. This is used by the `type_id` intrinsic.
6136 pub fn hash_crate_independent<'tcx>(tcx: &ctxt<'tcx>, ty: Ty<'tcx>, svh: &Svh) -> u64 {
6137 let mut state = SipHasher::new();
6138 helper(tcx, ty, svh, &mut state);
6139 return state.finish();
6141 fn helper<'tcx>(tcx: &ctxt<'tcx>, ty: Ty<'tcx>, svh: &Svh,
6142 state: &mut SipHasher) {
6143 macro_rules! byte { ($b:expr) => { ($b as u8).hash(state) } }
6144 macro_rules! hash { ($e:expr) => { $e.hash(state) } }
6146 let region = |&: state: &mut SipHasher, r: Region| {
6149 ReLateBound(db, BrAnon(i)) => {
6159 tcx.sess.bug("unexpected region found when hashing a type")
6163 let did = |&: state: &mut SipHasher, did: DefId| {
6164 let h = if ast_util::is_local(did) {
6167 tcx.sess.cstore.get_crate_hash(did.krate)
6169 h.as_str().hash(state);
6170 did.node.hash(state);
6172 let mt = |&: state: &mut SipHasher, mt: mt| {
6173 mt.mutbl.hash(state);
6175 let fn_sig = |&: state: &mut SipHasher, sig: &Binder<FnSig<'tcx>>| {
6176 let sig = anonymize_late_bound_regions(tcx, sig).0;
6177 for a in sig.inputs.iter() { helper(tcx, *a, svh, state); }
6178 if let ty::FnConverging(output) = sig.output {
6179 helper(tcx, output, svh, state);
6182 maybe_walk_ty(ty, |ty| {
6184 ty_bool => byte!(2),
6185 ty_char => byte!(3),
6208 ty_vec(_, Some(n)) => {
6212 ty_vec(_, None) => {
6224 ty_bare_fn(opt_def_id, ref b) => {
6229 fn_sig(state, &b.sig);
6232 ty_trait(ref data) => {
6234 did(state, data.principal_def_id());
6237 let principal = anonymize_late_bound_regions(tcx, &data.principal).0;
6238 for subty in principal.substs.types.iter() {
6239 helper(tcx, *subty, svh, state);
6244 ty_struct(d, _) => {
6248 ty_tup(ref inner) => {
6256 hash!(token::get_name(p.name));
6258 ty_open(_) => byte!(22),
6259 ty_infer(_) => unreachable!(),
6260 ty_err => byte!(23),
6261 ty_unboxed_closure(d, r, _) => {
6266 ty_projection(ref data) => {
6268 did(state, data.trait_ref.def_id);
6269 hash!(token::get_name(data.item_name));
6278 pub fn to_string(self) -> &'static str {
6281 Contravariant => "-",
6288 /// Construct a parameter environment suitable for static contexts or other contexts where there
6289 /// are no free type/lifetime parameters in scope.
6290 pub fn empty_parameter_environment<'a,'tcx>(cx: &'a ctxt<'tcx>) -> ParameterEnvironment<'a,'tcx> {
6291 ty::ParameterEnvironment { tcx: cx,
6292 free_substs: Substs::empty(),
6293 caller_bounds: GenericBounds::empty(),
6294 implicit_region_bound: ty::ReEmpty,
6295 selection_cache: traits::SelectionCache::new(), }
6298 /// See `ParameterEnvironment` struct def'n for details
6299 pub fn construct_parameter_environment<'a,'tcx>(
6300 tcx: &'a ctxt<'tcx>,
6301 generics: &ty::Generics<'tcx>,
6302 free_id: ast::NodeId)
6303 -> ParameterEnvironment<'a, 'tcx>
6307 // Construct the free substs.
6311 let mut types = VecPerParamSpace::empty();
6312 push_types_from_defs(tcx, &mut types, generics.types.as_slice());
6314 // map bound 'a => free 'a
6315 let mut regions = VecPerParamSpace::empty();
6316 push_region_params(&mut regions, free_id, generics.regions.as_slice());
6318 let free_substs = Substs {
6320 regions: subst::NonerasedRegions(regions)
6323 let free_id_scope = region::CodeExtent::from_node_id(free_id);
6326 // Compute the bounds on Self and the type parameters.
6329 let bounds = generics.to_bounds(tcx, &free_substs);
6330 let bounds = liberate_late_bound_regions(tcx, free_id_scope, &ty::Binder(bounds));
6333 // Compute region bounds. For now, these relations are stored in a
6334 // global table on the tcx, so just enter them there. I'm not
6335 // crazy about this scheme, but it's convenient, at least.
6338 record_region_bounds(tcx, &bounds);
6340 debug!("construct_parameter_environment: free_id={:?} free_subst={:?} bounds={:?}",
6342 free_substs.repr(tcx),
6345 return ty::ParameterEnvironment {
6347 free_substs: free_substs,
6348 implicit_region_bound: ty::ReScope(free_id_scope),
6349 caller_bounds: bounds,
6350 selection_cache: traits::SelectionCache::new(),
6353 fn push_region_params(regions: &mut VecPerParamSpace<ty::Region>,
6354 free_id: ast::NodeId,
6355 region_params: &[RegionParameterDef])
6357 for r in region_params.iter() {
6358 regions.push(r.space, ty::free_region_from_def(free_id, r));
6362 fn push_types_from_defs<'tcx>(tcx: &ty::ctxt<'tcx>,
6363 types: &mut VecPerParamSpace<Ty<'tcx>>,
6364 defs: &[TypeParameterDef<'tcx>]) {
6365 for def in defs.iter() {
6366 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
6368 let ty = ty::mk_param_from_def(tcx, def);
6369 types.push(def.space, ty);
6373 fn record_region_bounds<'tcx>(tcx: &ty::ctxt<'tcx>, bounds: &GenericBounds<'tcx>) {
6374 debug!("record_region_bounds(bounds={:?})", bounds.repr(tcx));
6376 for predicate in bounds.predicates.iter() {
6378 Predicate::Projection(..) |
6379 Predicate::Trait(..) |
6380 Predicate::Equate(..) |
6381 Predicate::TypeOutlives(..) => {
6382 // No region bounds here
6384 Predicate::RegionOutlives(ty::Binder(ty::OutlivesPredicate(r_a, r_b))) => {
6386 (ty::ReFree(fr_a), ty::ReFree(fr_b)) => {
6387 // Record that `'a:'b`. Or, put another way, `'b <= 'a`.
6388 tcx.region_maps.relate_free_regions(fr_b, fr_a);
6391 // All named regions are instantiated with free regions.
6393 format!("record_region_bounds: non free region: {} / {}",
6395 r_b.repr(tcx)).as_slice());
6405 pub fn from_mutbl(m: ast::Mutability) -> BorrowKind {
6407 ast::MutMutable => MutBorrow,
6408 ast::MutImmutable => ImmBorrow,
6412 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
6413 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
6414 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
6416 pub fn to_mutbl_lossy(self) -> ast::Mutability {
6418 MutBorrow => ast::MutMutable,
6419 ImmBorrow => ast::MutImmutable,
6421 // We have no type corresponding to a unique imm borrow, so
6422 // use `&mut`. It gives all the capabilities of an `&uniq`
6423 // and hence is a safe "over approximation".
6424 UniqueImmBorrow => ast::MutMutable,
6428 pub fn to_user_str(&self) -> &'static str {
6430 MutBorrow => "mutable",
6431 ImmBorrow => "immutable",
6432 UniqueImmBorrow => "uniquely immutable",
6437 impl<'tcx> ctxt<'tcx> {
6438 pub fn capture_mode(&self, closure_expr_id: ast::NodeId)
6439 -> ast::CaptureClause {
6440 self.capture_modes.borrow()[closure_expr_id].clone()
6443 pub fn is_method_call(&self, expr_id: ast::NodeId) -> bool {
6444 self.method_map.borrow().contains_key(&MethodCall::expr(expr_id))
6448 impl<'a,'tcx> mc::Typer<'tcx> for ParameterEnvironment<'a,'tcx> {
6449 fn tcx(&self) -> &ty::ctxt<'tcx> {
6453 fn node_ty(&self, id: ast::NodeId) -> mc::McResult<Ty<'tcx>> {
6454 Ok(ty::node_id_to_type(self.tcx, id))
6457 fn expr_ty_adjusted(&self, expr: &ast::Expr) -> mc::McResult<Ty<'tcx>> {
6458 Ok(ty::expr_ty_adjusted(self.tcx, expr))
6461 fn node_method_ty(&self, method_call: ty::MethodCall) -> Option<Ty<'tcx>> {
6462 self.tcx.method_map.borrow().get(&method_call).map(|method| method.ty)
6465 fn node_method_origin(&self, method_call: ty::MethodCall)
6466 -> Option<ty::MethodOrigin<'tcx>>
6468 self.tcx.method_map.borrow().get(&method_call).map(|method| method.origin.clone())
6471 fn adjustments(&self) -> &RefCell<NodeMap<ty::AutoAdjustment<'tcx>>> {
6472 &self.tcx.adjustments
6475 fn is_method_call(&self, id: ast::NodeId) -> bool {
6476 self.tcx.is_method_call(id)
6479 fn temporary_scope(&self, rvalue_id: ast::NodeId) -> Option<region::CodeExtent> {
6480 self.tcx.region_maps.temporary_scope(rvalue_id)
6483 fn upvar_borrow(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarBorrow> {
6484 Some(self.tcx.upvar_borrow_map.borrow()[upvar_id].clone())
6487 fn capture_mode(&self, closure_expr_id: ast::NodeId)
6488 -> ast::CaptureClause {
6489 self.tcx.capture_mode(closure_expr_id)
6492 fn type_moves_by_default(&self, span: Span, ty: Ty<'tcx>) -> bool {
6493 type_moves_by_default(self, span, ty)
6497 impl<'a,'tcx> UnboxedClosureTyper<'tcx> for ty::ParameterEnvironment<'a,'tcx> {
6498 fn param_env<'b>(&'b self) -> &'b ty::ParameterEnvironment<'b,'tcx> {
6502 fn unboxed_closure_kind(&self,
6504 -> ty::UnboxedClosureKind
6506 self.tcx.unboxed_closure_kind(def_id)
6509 fn unboxed_closure_type(&self,
6511 substs: &subst::Substs<'tcx>)
6512 -> ty::ClosureTy<'tcx>
6514 self.tcx.unboxed_closure_type(def_id, substs)
6517 fn unboxed_closure_upvars(&self,
6519 substs: &Substs<'tcx>)
6520 -> Option<Vec<UnboxedClosureUpvar<'tcx>>>
6522 unboxed_closure_upvars(self, def_id, substs)
6527 /// The category of explicit self.
6528 #[derive(Clone, Copy, Eq, PartialEq, Show)]
6529 pub enum ExplicitSelfCategory {
6530 StaticExplicitSelfCategory,
6531 ByValueExplicitSelfCategory,
6532 ByReferenceExplicitSelfCategory(Region, ast::Mutability),
6533 ByBoxExplicitSelfCategory,
6536 /// Pushes all the lifetimes in the given type onto the given list. A
6537 /// "lifetime in a type" is a lifetime specified by a reference or a lifetime
6538 /// in a list of type substitutions. This does *not* traverse into nominal
6539 /// types, nor does it resolve fictitious types.
6540 pub fn accumulate_lifetimes_in_type(accumulator: &mut Vec<ty::Region>,
6544 ty_rptr(region, _) => {
6545 accumulator.push(*region)
6547 ty_trait(ref t) => {
6548 accumulator.push_all(t.principal.0.substs.regions().as_slice());
6550 ty_enum(_, substs) |
6551 ty_struct(_, substs) => {
6552 accum_substs(accumulator, substs);
6554 ty_unboxed_closure(_, region, substs) => {
6555 accumulator.push(*region);
6556 accum_substs(accumulator, substs);
6578 fn accum_substs(accumulator: &mut Vec<Region>, substs: &Substs) {
6579 match substs.regions {
6580 subst::ErasedRegions => {}
6581 subst::NonerasedRegions(ref regions) => {
6582 for region in regions.iter() {
6583 accumulator.push(*region)
6590 /// A free variable referred to in a function.
6591 #[derive(Copy, RustcEncodable, RustcDecodable)]
6592 pub struct Freevar {
6593 /// The variable being accessed free.
6596 // First span where it is accessed (there can be multiple).
6600 pub type FreevarMap = NodeMap<Vec<Freevar>>;
6602 pub type CaptureModeMap = NodeMap<ast::CaptureClause>;
6604 // Trait method resolution
6605 pub type TraitMap = NodeMap<Vec<DefId>>;
6607 // Map from the NodeId of a glob import to a list of items which are actually
6609 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
6611 pub fn with_freevars<T, F>(tcx: &ty::ctxt, fid: ast::NodeId, f: F) -> T where
6612 F: FnOnce(&[Freevar]) -> T,
6614 match tcx.freevars.borrow().get(&fid) {
6620 impl<'tcx> AutoAdjustment<'tcx> {
6621 pub fn is_identity(&self) -> bool {
6623 AdjustReifyFnPointer(..) => false,
6624 AdjustDerefRef(ref r) => r.is_identity(),
6629 impl<'tcx> AutoDerefRef<'tcx> {
6630 pub fn is_identity(&self) -> bool {
6631 self.autoderefs == 0 && self.autoref.is_none()
6635 /// Replace any late-bound regions bound in `value` with free variants attached to scope-id
6637 pub fn liberate_late_bound_regions<'tcx, T>(
6638 tcx: &ty::ctxt<'tcx>,
6639 scope: region::CodeExtent,
6642 where T : TypeFoldable<'tcx> + Repr<'tcx>
6644 replace_late_bound_regions(
6646 |br| ty::ReFree(ty::FreeRegion{scope: scope, bound_region: br})).0
6649 pub fn count_late_bound_regions<'tcx, T>(
6650 tcx: &ty::ctxt<'tcx>,
6653 where T : TypeFoldable<'tcx> + Repr<'tcx>
6655 let (_, skol_map) = replace_late_bound_regions(tcx, value, |_| ty::ReStatic);
6659 pub fn binds_late_bound_regions<'tcx, T>(
6660 tcx: &ty::ctxt<'tcx>,
6663 where T : TypeFoldable<'tcx> + Repr<'tcx>
6665 count_late_bound_regions(tcx, value) > 0
6668 pub fn assert_no_late_bound_regions<'tcx, T>(
6669 tcx: &ty::ctxt<'tcx>,
6672 where T : TypeFoldable<'tcx> + Repr<'tcx> + Clone
6674 assert!(!binds_late_bound_regions(tcx, value));
6678 /// Replace any late-bound regions bound in `value` with `'static`. Useful in trans but also
6679 /// method lookup and a few other places where precise region relationships are not required.
6680 pub fn erase_late_bound_regions<'tcx, T>(
6681 tcx: &ty::ctxt<'tcx>,
6684 where T : TypeFoldable<'tcx> + Repr<'tcx>
6686 replace_late_bound_regions(tcx, value, |_| ty::ReStatic).0
6689 /// Rewrite any late-bound regions so that they are anonymous. Region numbers are
6690 /// assigned starting at 1 and increasing monotonically in the order traversed
6691 /// by the fold operation.
6693 /// The chief purpose of this function is to canonicalize regions so that two
6694 /// `FnSig`s or `TraitRef`s which are equivalent up to region naming will become
6695 /// structurally identical. For example, `for<'a, 'b> fn(&'a int, &'b int)` and
6696 /// `for<'a, 'b> fn(&'b int, &'a int)` will become identical after anonymization.
6697 pub fn anonymize_late_bound_regions<'tcx, T>(
6701 where T : TypeFoldable<'tcx> + Repr<'tcx>,
6703 let mut counter = 0;
6704 ty::Binder(replace_late_bound_regions(tcx, sig, |_| {
6706 ReLateBound(ty::DebruijnIndex::new(1), BrAnon(counter))
6710 /// Replaces the late-bound-regions in `value` that are bound by `value`.
6711 pub fn replace_late_bound_regions<'tcx, T, F>(
6712 tcx: &ty::ctxt<'tcx>,
6715 -> (T, FnvHashMap<ty::BoundRegion,ty::Region>)
6716 where T : TypeFoldable<'tcx> + Repr<'tcx>,
6717 F : FnMut(BoundRegion) -> ty::Region,
6719 debug!("replace_late_bound_regions({})", binder.repr(tcx));
6721 let mut map = FnvHashMap();
6723 // Note: fold the field `0`, not the binder, so that late-bound
6724 // regions bound by `binder` are considered free.
6725 let value = ty_fold::fold_regions(tcx, &binder.0, |region, current_depth| {
6726 debug!("region={}", region.repr(tcx));
6728 ty::ReLateBound(debruijn, br) if debruijn.depth == current_depth => {
6730 * map.entry(br).get().unwrap_or_else(
6731 |vacant_entry| vacant_entry.insert(mapf(br)));
6733 if let ty::ReLateBound(debruijn1, br) = region {
6734 // If the callback returns a late-bound region,
6735 // that region should always use depth 1. Then we
6736 // adjust it to the correct depth.
6737 assert_eq!(debruijn1.depth, 1);
6738 ty::ReLateBound(debruijn, br)
6749 debug!("resulting map: {:?} value: {:?}", map, value.repr(tcx));
6753 impl DebruijnIndex {
6754 pub fn new(depth: u32) -> DebruijnIndex {
6756 DebruijnIndex { depth: depth }
6759 pub fn shifted(&self, amount: u32) -> DebruijnIndex {
6760 DebruijnIndex { depth: self.depth + amount }
6764 impl<'tcx> Repr<'tcx> for AutoAdjustment<'tcx> {
6765 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
6767 AdjustReifyFnPointer(def_id) => {
6768 format!("AdjustReifyFnPointer({})", def_id.repr(tcx))
6770 AdjustDerefRef(ref data) => {
6777 impl<'tcx> Repr<'tcx> for UnsizeKind<'tcx> {
6778 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
6780 UnsizeLength(n) => format!("UnsizeLength({})", n),
6781 UnsizeStruct(ref k, n) => format!("UnsizeStruct({},{})", k.repr(tcx), n),
6782 UnsizeVtable(ref a, ref b) => format!("UnsizeVtable({},{})", a.repr(tcx), b.repr(tcx)),
6787 impl<'tcx> Repr<'tcx> for AutoDerefRef<'tcx> {
6788 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
6789 format!("AutoDerefRef({}, {})", self.autoderefs, self.autoref.repr(tcx))
6793 impl<'tcx> Repr<'tcx> for AutoRef<'tcx> {
6794 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
6796 AutoPtr(a, b, ref c) => {
6797 format!("AutoPtr({},{:?},{})", a.repr(tcx), b, c.repr(tcx))
6799 AutoUnsize(ref a) => {
6800 format!("AutoUnsize({})", a.repr(tcx))
6802 AutoUnsizeUniq(ref a) => {
6803 format!("AutoUnsizeUniq({})", a.repr(tcx))
6805 AutoUnsafe(ref a, ref b) => {
6806 format!("AutoUnsafe({:?},{})", a, b.repr(tcx))
6812 impl<'tcx> Repr<'tcx> for TyTrait<'tcx> {
6813 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
6814 format!("TyTrait({},{})",
6815 self.principal.repr(tcx),
6816 self.bounds.repr(tcx))
6820 impl<'tcx> Repr<'tcx> for ty::Predicate<'tcx> {
6821 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
6823 Predicate::Trait(ref a) => a.repr(tcx),
6824 Predicate::Equate(ref pair) => pair.repr(tcx),
6825 Predicate::RegionOutlives(ref pair) => pair.repr(tcx),
6826 Predicate::TypeOutlives(ref pair) => pair.repr(tcx),
6827 Predicate::Projection(ref pair) => pair.repr(tcx),
6832 impl<'tcx> Repr<'tcx> for vtable_origin<'tcx> {
6833 fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
6835 vtable_static(def_id, ref tys, ref vtable_res) => {
6836 format!("vtable_static({:?}:{}, {}, {})",
6838 ty::item_path_str(tcx, def_id),
6840 vtable_res.repr(tcx))
6843 vtable_param(x, y) => {
6844 format!("vtable_param({:?}, {})", x, y)
6847 vtable_unboxed_closure(def_id) => {
6848 format!("vtable_unboxed_closure({:?})", def_id)
6852 format!("vtable_error")
6858 pub fn make_substs_for_receiver_types<'tcx>(tcx: &ty::ctxt<'tcx>,
6859 trait_ref: &ty::TraitRef<'tcx>,
6860 method: &ty::Method<'tcx>)
6861 -> subst::Substs<'tcx>
6864 * Substitutes the values for the receiver's type parameters
6865 * that are found in method, leaving the method's type parameters
6869 let meth_tps: Vec<Ty> =
6870 method.generics.types.get_slice(subst::FnSpace)
6872 .map(|def| ty::mk_param_from_def(tcx, def))
6874 let meth_regions: Vec<ty::Region> =
6875 method.generics.regions.get_slice(subst::FnSpace)
6877 .map(|def| ty::ReEarlyBound(def.def_id.node, def.space,
6878 def.index, def.name))
6880 trait_ref.substs.clone().with_method(meth_tps, meth_regions)
6884 pub enum CopyImplementationError {
6885 FieldDoesNotImplementCopy(ast::Name),
6886 VariantDoesNotImplementCopy(ast::Name),
6891 pub fn can_type_implement_copy<'a,'tcx>(param_env: &ParameterEnvironment<'a, 'tcx>,
6893 self_type: Ty<'tcx>)
6894 -> Result<(),CopyImplementationError>
6896 let tcx = param_env.tcx;
6898 let did = match self_type.sty {
6899 ty::ty_struct(struct_did, substs) => {
6900 let fields = ty::struct_fields(tcx, struct_did, substs);
6901 for field in fields.iter() {
6902 if type_moves_by_default(param_env, span, field.mt.ty) {
6903 return Err(FieldDoesNotImplementCopy(field.name))
6908 ty::ty_enum(enum_did, substs) => {
6909 let enum_variants = ty::enum_variants(tcx, enum_did);
6910 for variant in enum_variants.iter() {
6911 for variant_arg_type in variant.args.iter() {
6912 let substd_arg_type =
6913 variant_arg_type.subst(tcx, substs);
6914 if type_moves_by_default(param_env, span, substd_arg_type) {
6915 return Err(VariantDoesNotImplementCopy(variant.name))
6921 _ => return Err(TypeIsStructural),
6924 if ty::has_dtor(tcx, did) {
6925 return Err(TypeHasDestructor)
6931 // FIXME(#20298) -- all of these types basically walk various
6932 // structures to test whether types/regions are reachable with various
6933 // properties. It should be possible to express them in terms of one
6934 // common "walker" trait or something.
6936 pub trait RegionEscape {
6937 fn has_escaping_regions(&self) -> bool {
6938 self.has_regions_escaping_depth(0)
6941 fn has_regions_escaping_depth(&self, depth: u32) -> bool;
6944 impl<'tcx> RegionEscape for Ty<'tcx> {
6945 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6946 ty::type_escapes_depth(*self, depth)
6950 impl<'tcx> RegionEscape for Substs<'tcx> {
6951 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6952 self.types.has_regions_escaping_depth(depth) ||
6953 self.regions.has_regions_escaping_depth(depth)
6957 impl<'tcx,T:RegionEscape> RegionEscape for VecPerParamSpace<T> {
6958 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6959 self.iter_enumerated().any(|(space, _, t)| {
6960 if space == subst::FnSpace {
6961 t.has_regions_escaping_depth(depth+1)
6963 t.has_regions_escaping_depth(depth)
6969 impl<'tcx> RegionEscape for TypeScheme<'tcx> {
6970 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6971 self.ty.has_regions_escaping_depth(depth) ||
6972 self.generics.has_regions_escaping_depth(depth)
6976 impl RegionEscape for Region {
6977 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6978 self.escapes_depth(depth)
6982 impl<'tcx> RegionEscape for Generics<'tcx> {
6983 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6984 self.predicates.has_regions_escaping_depth(depth)
6988 impl<'tcx> RegionEscape for Predicate<'tcx> {
6989 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6991 Predicate::Trait(ref data) => data.has_regions_escaping_depth(depth),
6992 Predicate::Equate(ref data) => data.has_regions_escaping_depth(depth),
6993 Predicate::RegionOutlives(ref data) => data.has_regions_escaping_depth(depth),
6994 Predicate::TypeOutlives(ref data) => data.has_regions_escaping_depth(depth),
6995 Predicate::Projection(ref data) => data.has_regions_escaping_depth(depth),
7000 impl<'tcx> RegionEscape for TraitRef<'tcx> {
7001 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7002 self.substs.types.iter().any(|t| t.has_regions_escaping_depth(depth)) ||
7003 self.substs.regions.has_regions_escaping_depth(depth)
7007 impl<'tcx> RegionEscape for subst::RegionSubsts {
7008 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7010 subst::ErasedRegions => false,
7011 subst::NonerasedRegions(ref r) => {
7012 r.iter().any(|t| t.has_regions_escaping_depth(depth))
7018 impl<'tcx,T:RegionEscape> RegionEscape for Binder<T> {
7019 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7020 self.0.has_regions_escaping_depth(depth + 1)
7024 impl<'tcx> RegionEscape for EquatePredicate<'tcx> {
7025 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7026 self.0.has_regions_escaping_depth(depth) || self.1.has_regions_escaping_depth(depth)
7030 impl<'tcx> RegionEscape for TraitPredicate<'tcx> {
7031 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7032 self.trait_ref.has_regions_escaping_depth(depth)
7036 impl<T:RegionEscape,U:RegionEscape> RegionEscape for OutlivesPredicate<T,U> {
7037 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7038 self.0.has_regions_escaping_depth(depth) || self.1.has_regions_escaping_depth(depth)
7042 impl<'tcx> RegionEscape for ProjectionPredicate<'tcx> {
7043 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7044 self.projection_ty.has_regions_escaping_depth(depth) ||
7045 self.ty.has_regions_escaping_depth(depth)
7049 impl<'tcx> RegionEscape for ProjectionTy<'tcx> {
7050 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
7051 self.trait_ref.has_regions_escaping_depth(depth)
7055 impl<'tcx> Repr<'tcx> for ty::ProjectionPredicate<'tcx> {
7056 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
7057 format!("ProjectionPredicate({}, {})",
7058 self.projection_ty.repr(tcx),
7063 pub trait HasProjectionTypes {
7064 fn has_projection_types(&self) -> bool;
7067 impl<'tcx,T:HasProjectionTypes> HasProjectionTypes for Vec<T> {
7068 fn has_projection_types(&self) -> bool {
7069 self.iter().any(|p| p.has_projection_types())
7073 impl<'tcx,T:HasProjectionTypes> HasProjectionTypes for VecPerParamSpace<T> {
7074 fn has_projection_types(&self) -> bool {
7075 self.iter().any(|p| p.has_projection_types())
7079 impl<'tcx> HasProjectionTypes for ClosureTy<'tcx> {
7080 fn has_projection_types(&self) -> bool {
7081 self.sig.has_projection_types()
7085 impl<'tcx> HasProjectionTypes for UnboxedClosureUpvar<'tcx> {
7086 fn has_projection_types(&self) -> bool {
7087 self.ty.has_projection_types()
7091 impl<'tcx> HasProjectionTypes for ty::GenericBounds<'tcx> {
7092 fn has_projection_types(&self) -> bool {
7093 self.predicates.has_projection_types()
7097 impl<'tcx> HasProjectionTypes for Predicate<'tcx> {
7098 fn has_projection_types(&self) -> bool {
7100 Predicate::Trait(ref data) => data.has_projection_types(),
7101 Predicate::Equate(ref data) => data.has_projection_types(),
7102 Predicate::RegionOutlives(ref data) => data.has_projection_types(),
7103 Predicate::TypeOutlives(ref data) => data.has_projection_types(),
7104 Predicate::Projection(ref data) => data.has_projection_types(),
7109 impl<'tcx> HasProjectionTypes for TraitPredicate<'tcx> {
7110 fn has_projection_types(&self) -> bool {
7111 self.trait_ref.has_projection_types()
7115 impl<'tcx> HasProjectionTypes for EquatePredicate<'tcx> {
7116 fn has_projection_types(&self) -> bool {
7117 self.0.has_projection_types() || self.1.has_projection_types()
7121 impl HasProjectionTypes for Region {
7122 fn has_projection_types(&self) -> bool {
7127 impl<T:HasProjectionTypes,U:HasProjectionTypes> HasProjectionTypes for OutlivesPredicate<T,U> {
7128 fn has_projection_types(&self) -> bool {
7129 self.0.has_projection_types() || self.1.has_projection_types()
7133 impl<'tcx> HasProjectionTypes for ProjectionPredicate<'tcx> {
7134 fn has_projection_types(&self) -> bool {
7135 self.projection_ty.has_projection_types() || self.ty.has_projection_types()
7139 impl<'tcx> HasProjectionTypes for ProjectionTy<'tcx> {
7140 fn has_projection_types(&self) -> bool {
7141 self.trait_ref.has_projection_types()
7145 impl<'tcx> HasProjectionTypes for Ty<'tcx> {
7146 fn has_projection_types(&self) -> bool {
7147 ty::type_has_projection(*self)
7151 impl<'tcx> HasProjectionTypes for TraitRef<'tcx> {
7152 fn has_projection_types(&self) -> bool {
7153 self.substs.has_projection_types()
7157 impl<'tcx> HasProjectionTypes for subst::Substs<'tcx> {
7158 fn has_projection_types(&self) -> bool {
7159 self.types.iter().any(|t| t.has_projection_types())
7163 impl<'tcx,T> HasProjectionTypes for Option<T>
7164 where T : HasProjectionTypes
7166 fn has_projection_types(&self) -> bool {
7167 self.iter().any(|t| t.has_projection_types())
7171 impl<'tcx,T> HasProjectionTypes for Rc<T>
7172 where T : HasProjectionTypes
7174 fn has_projection_types(&self) -> bool {
7175 (**self).has_projection_types()
7179 impl<'tcx,T> HasProjectionTypes for Box<T>
7180 where T : HasProjectionTypes
7182 fn has_projection_types(&self) -> bool {
7183 (**self).has_projection_types()
7187 impl<T> HasProjectionTypes for Binder<T>
7188 where T : HasProjectionTypes
7190 fn has_projection_types(&self) -> bool {
7191 self.0.has_projection_types()
7195 impl<'tcx> HasProjectionTypes for FnOutput<'tcx> {
7196 fn has_projection_types(&self) -> bool {
7198 FnConverging(t) => t.has_projection_types(),
7199 FnDiverging => false,
7204 impl<'tcx> HasProjectionTypes for FnSig<'tcx> {
7205 fn has_projection_types(&self) -> bool {
7206 self.inputs.iter().any(|t| t.has_projection_types()) ||
7207 self.output.has_projection_types()
7211 impl<'tcx> HasProjectionTypes for field<'tcx> {
7212 fn has_projection_types(&self) -> bool {
7213 self.mt.ty.has_projection_types()
7217 impl<'tcx> HasProjectionTypes for BareFnTy<'tcx> {
7218 fn has_projection_types(&self) -> bool {
7219 self.sig.has_projection_types()
7223 pub trait ReferencesError {
7224 fn references_error(&self) -> bool;
7227 impl<T:ReferencesError> ReferencesError for Binder<T> {
7228 fn references_error(&self) -> bool {
7229 self.0.references_error()
7233 impl<T:ReferencesError> ReferencesError for Rc<T> {
7234 fn references_error(&self) -> bool {
7235 (&**self).references_error()
7239 impl<'tcx> ReferencesError for TraitPredicate<'tcx> {
7240 fn references_error(&self) -> bool {
7241 self.trait_ref.references_error()
7245 impl<'tcx> ReferencesError for ProjectionPredicate<'tcx> {
7246 fn references_error(&self) -> bool {
7247 self.projection_ty.trait_ref.references_error() || self.ty.references_error()
7251 impl<'tcx> ReferencesError for TraitRef<'tcx> {
7252 fn references_error(&self) -> bool {
7253 self.input_types().iter().any(|t| t.references_error())
7257 impl<'tcx> ReferencesError for Ty<'tcx> {
7258 fn references_error(&self) -> bool {
7259 type_is_error(*self)
7263 impl<'tcx> ReferencesError for Predicate<'tcx> {
7264 fn references_error(&self) -> bool {
7266 Predicate::Trait(ref data) => data.references_error(),
7267 Predicate::Equate(ref data) => data.references_error(),
7268 Predicate::RegionOutlives(ref data) => data.references_error(),
7269 Predicate::TypeOutlives(ref data) => data.references_error(),
7270 Predicate::Projection(ref data) => data.references_error(),
7275 impl<A,B> ReferencesError for OutlivesPredicate<A,B>
7276 where A : ReferencesError, B : ReferencesError
7278 fn references_error(&self) -> bool {
7279 self.0.references_error() || self.1.references_error()
7283 impl<'tcx> ReferencesError for EquatePredicate<'tcx>
7285 fn references_error(&self) -> bool {
7286 self.0.references_error() || self.1.references_error()
7290 impl ReferencesError for Region
7292 fn references_error(&self) -> bool {
7297 impl<'tcx> Repr<'tcx> for ClosureTy<'tcx> {
7298 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
7299 format!("ClosureTy({},{},{},{},{})",
7302 self.bounds.repr(tcx),
7308 impl<'tcx> Repr<'tcx> for UnboxedClosureUpvar<'tcx> {
7309 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
7310 format!("UnboxedClosureUpvar({},{})",
7316 impl<'tcx> Repr<'tcx> for field<'tcx> {
7317 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
7318 format!("field({},{})",
7319 self.name.repr(tcx),
7324 impl<'a, 'tcx> Repr<'tcx> for ParameterEnvironment<'a, 'tcx> {
7325 fn repr(&self, tcx: &ctxt<'tcx>) -> String {
7326 format!("ParameterEnvironment(\
7328 implicit_region_bound={}, \
7330 self.free_substs.repr(tcx),
7331 self.implicit_region_bound.repr(tcx),
7332 self.caller_bounds.repr(tcx))