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1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
4 //
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.
10
11 pub use self::ImplOrTraitItemId::*;
12 pub use self::ClosureKind::*;
13 pub use self::Variance::*;
14 pub use self::DtorKind::*;
15 pub use self::ImplOrTraitItemContainer::*;
16 pub use self::BorrowKind::*;
17 pub use self::ImplOrTraitItem::*;
18 pub use self::IntVarValue::*;
19 pub use self::LvaluePreference::*;
20 pub use self::fold::TypeFoldable;
21
22 use dep_graph::{self, DepNode};
23 use front::map as ast_map;
24 use front::map::LinkedPath;
25 use middle;
26 use middle::cstore::{self, CrateStore, LOCAL_CRATE};
27 use middle::def::{self, Def, ExportMap};
28 use middle::def_id::DefId;
29 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
30 use middle::region::{CodeExtent};
31 use middle::subst::{self, Subst, Substs, VecPerParamSpace};
32 use middle::traits;
33 use middle::ty;
34 use middle::ty::fold::TypeFolder;
35 use middle::ty::walk::TypeWalker;
36 use util::common::MemoizationMap;
37 use util::nodemap::{NodeMap, NodeSet};
38 use util::nodemap::FnvHashMap;
39
40 use serialize::{Encodable, Encoder, Decodable, Decoder};
41 use std::borrow::{Borrow, Cow};
42 use std::cell::Cell;
43 use std::hash::{Hash, Hasher};
44 use std::iter;
45 use std::rc::Rc;
46 use std::slice;
47 use std::vec::IntoIter;
48 use std::collections::{HashMap, HashSet};
49 use syntax::ast::{self, CrateNum, Name, NodeId};
50 use syntax::attr::{self, AttrMetaMethods};
51 use syntax::codemap::{DUMMY_SP, Span};
52 use syntax::parse::token::InternedString;
53
54 use rustc_front::hir;
55 use rustc_front::hir::{ItemImpl, ItemTrait, PatKind};
56 use rustc_front::intravisit::Visitor;
57
58 pub use self::sty::{Binder, DebruijnIndex};
59 pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
60 pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
61 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
62 pub use self::sty::{ClosureSubsts, TypeAndMut};
63 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
64 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
65 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
66 pub use self::sty::BoundRegion::*;
67 pub use self::sty::FnOutput::*;
68 pub use self::sty::InferTy::*;
69 pub use self::sty::Region::*;
70 pub use self::sty::TypeVariants::*;
71
72 pub use self::sty::BuiltinBound::Send as BoundSend;
73 pub use self::sty::BuiltinBound::Sized as BoundSized;
74 pub use self::sty::BuiltinBound::Copy as BoundCopy;
75 pub use self::sty::BuiltinBound::Sync as BoundSync;
76
77 pub use self::contents::TypeContents;
78 pub use self::context::{ctxt, tls};
79 pub use self::context::{CtxtArenas, Lift, Tables};
80
81 pub use self::trait_def::{TraitDef, TraitFlags};
82
83 pub mod adjustment;
84 pub mod cast;
85 pub mod error;
86 pub mod fast_reject;
87 pub mod fold;
88 pub mod _match;
89 pub mod maps;
90 pub mod outlives;
91 pub mod relate;
92 pub mod trait_def;
93 pub mod walk;
94 pub mod wf;
95 pub mod util;
96
97 mod contents;
98 mod context;
99 mod flags;
100 mod ivar;
101 mod structural_impls;
102 mod sty;
103
104 pub type Disr = u64;
105 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
106
107 // Data types
108
109 /// The complete set of all analyses described in this module. This is
110 /// produced by the driver and fed to trans and later passes.
111 pub struct CrateAnalysis<'a> {
112 pub export_map: ExportMap,
113 pub access_levels: middle::privacy::AccessLevels,
114 pub reachable: NodeSet,
115 pub name: &'a str,
116 pub glob_map: Option<GlobMap>,
117 }
118
119 #[derive(Copy, Clone)]
120 pub enum DtorKind {
121 NoDtor,
122 TraitDtor(bool)
123 }
124
125 impl DtorKind {
126 pub fn is_present(&self) -> bool {
127 match *self {
128 TraitDtor(..) => true,
129 _ => false
130 }
131 }
132
133 pub fn has_drop_flag(&self) -> bool {
134 match self {
135 &NoDtor => false,
136 &TraitDtor(flag) => flag
137 }
138 }
139 }
140
141 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
142 pub enum ImplOrTraitItemContainer {
143 TraitContainer(DefId),
144 ImplContainer(DefId),
145 }
146
147 impl ImplOrTraitItemContainer {
148 pub fn id(&self) -> DefId {
149 match *self {
150 TraitContainer(id) => id,
151 ImplContainer(id) => id,
152 }
153 }
154 }
155
156 #[derive(Clone)]
157 pub enum ImplOrTraitItem<'tcx> {
158 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
159 MethodTraitItem(Rc<Method<'tcx>>),
160 TypeTraitItem(Rc<AssociatedType<'tcx>>),
161 }
162
163 impl<'tcx> ImplOrTraitItem<'tcx> {
164 fn id(&self) -> ImplOrTraitItemId {
165 match *self {
166 ConstTraitItem(ref associated_const) => {
167 ConstTraitItemId(associated_const.def_id)
168 }
169 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
170 TypeTraitItem(ref associated_type) => {
171 TypeTraitItemId(associated_type.def_id)
172 }
173 }
174 }
175
176 pub fn def_id(&self) -> DefId {
177 match *self {
178 ConstTraitItem(ref associated_const) => associated_const.def_id,
179 MethodTraitItem(ref method) => method.def_id,
180 TypeTraitItem(ref associated_type) => associated_type.def_id,
181 }
182 }
183
184 pub fn name(&self) -> Name {
185 match *self {
186 ConstTraitItem(ref associated_const) => associated_const.name,
187 MethodTraitItem(ref method) => method.name,
188 TypeTraitItem(ref associated_type) => associated_type.name,
189 }
190 }
191
192 pub fn vis(&self) -> hir::Visibility {
193 match *self {
194 ConstTraitItem(ref associated_const) => associated_const.vis,
195 MethodTraitItem(ref method) => method.vis,
196 TypeTraitItem(ref associated_type) => associated_type.vis,
197 }
198 }
199
200 pub fn container(&self) -> ImplOrTraitItemContainer {
201 match *self {
202 ConstTraitItem(ref associated_const) => associated_const.container,
203 MethodTraitItem(ref method) => method.container,
204 TypeTraitItem(ref associated_type) => associated_type.container,
205 }
206 }
207
208 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
209 match *self {
210 MethodTraitItem(ref m) => Some((*m).clone()),
211 _ => None,
212 }
213 }
214 }
215
216 #[derive(Clone, Copy, Debug)]
217 pub enum ImplOrTraitItemId {
218 ConstTraitItemId(DefId),
219 MethodTraitItemId(DefId),
220 TypeTraitItemId(DefId),
221 }
222
223 impl ImplOrTraitItemId {
224 pub fn def_id(&self) -> DefId {
225 match *self {
226 ConstTraitItemId(def_id) => def_id,
227 MethodTraitItemId(def_id) => def_id,
228 TypeTraitItemId(def_id) => def_id,
229 }
230 }
231 }
232
233 #[derive(Clone, Debug)]
234 pub struct Method<'tcx> {
235 pub name: Name,
236 pub generics: Generics<'tcx>,
237 pub predicates: GenericPredicates<'tcx>,
238 pub fty: BareFnTy<'tcx>,
239 pub explicit_self: ExplicitSelfCategory,
240 pub vis: hir::Visibility,
241 pub def_id: DefId,
242 pub container: ImplOrTraitItemContainer,
243 }
244
245 impl<'tcx> Method<'tcx> {
246 pub fn new(name: Name,
247 generics: ty::Generics<'tcx>,
248 predicates: GenericPredicates<'tcx>,
249 fty: BareFnTy<'tcx>,
250 explicit_self: ExplicitSelfCategory,
251 vis: hir::Visibility,
252 def_id: DefId,
253 container: ImplOrTraitItemContainer)
254 -> Method<'tcx> {
255 Method {
256 name: name,
257 generics: generics,
258 predicates: predicates,
259 fty: fty,
260 explicit_self: explicit_self,
261 vis: vis,
262 def_id: def_id,
263 container: container,
264 }
265 }
266
267 pub fn container_id(&self) -> DefId {
268 match self.container {
269 TraitContainer(id) => id,
270 ImplContainer(id) => id,
271 }
272 }
273 }
274
275 impl<'tcx> PartialEq for Method<'tcx> {
276 #[inline]
277 fn eq(&self, other: &Self) -> bool { self.def_id == other.def_id }
278 }
279
280 impl<'tcx> Eq for Method<'tcx> {}
281
282 impl<'tcx> Hash for Method<'tcx> {
283 #[inline]
284 fn hash<H: Hasher>(&self, s: &mut H) {
285 self.def_id.hash(s)
286 }
287 }
288
289 #[derive(Clone, Copy, Debug)]
290 pub struct AssociatedConst<'tcx> {
291 pub name: Name,
292 pub ty: Ty<'tcx>,
293 pub vis: hir::Visibility,
294 pub def_id: DefId,
295 pub container: ImplOrTraitItemContainer,
296 pub has_value: bool
297 }
298
299 #[derive(Clone, Copy, Debug)]
300 pub struct AssociatedType<'tcx> {
301 pub name: Name,
302 pub ty: Option<Ty<'tcx>>,
303 pub vis: hir::Visibility,
304 pub def_id: DefId,
305 pub container: ImplOrTraitItemContainer,
306 }
307
308 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
309 pub struct ItemVariances {
310 pub types: VecPerParamSpace<Variance>,
311 pub regions: VecPerParamSpace<Variance>,
312 }
313
314 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
315 pub enum Variance {
316 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
317 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
318 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
319 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
320 }
321
322 #[derive(Clone, Copy, Debug)]
323 pub struct MethodCallee<'tcx> {
324 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
325 pub def_id: DefId,
326 pub ty: Ty<'tcx>,
327 pub substs: &'tcx subst::Substs<'tcx>
328 }
329
330 /// With method calls, we store some extra information in
331 /// side tables (i.e method_map). We use
332 /// MethodCall as a key to index into these tables instead of
333 /// just directly using the expression's NodeId. The reason
334 /// for this being that we may apply adjustments (coercions)
335 /// with the resulting expression also needing to use the
336 /// side tables. The problem with this is that we don't
337 /// assign a separate NodeId to this new expression
338 /// and so it would clash with the base expression if both
339 /// needed to add to the side tables. Thus to disambiguate
340 /// we also keep track of whether there's an adjustment in
341 /// our key.
342 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
343 pub struct MethodCall {
344 pub expr_id: NodeId,
345 pub autoderef: u32
346 }
347
348 impl MethodCall {
349 pub fn expr(id: NodeId) -> MethodCall {
350 MethodCall {
351 expr_id: id,
352 autoderef: 0
353 }
354 }
355
356 pub fn autoderef(expr_id: NodeId, autoderef: u32) -> MethodCall {
357 MethodCall {
358 expr_id: expr_id,
359 autoderef: 1 + autoderef
360 }
361 }
362 }
363
364 // maps from an expression id that corresponds to a method call to the details
365 // of the method to be invoked
366 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
367
368 // Contains information needed to resolve types and (in the future) look up
369 // the types of AST nodes.
370 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
371 pub struct CReaderCacheKey {
372 pub cnum: CrateNum,
373 pub pos: usize,
374 }
375
376 /// A restriction that certain types must be the same size. The use of
377 /// `transmute` gives rise to these restrictions. These generally
378 /// cannot be checked until trans; therefore, each call to `transmute`
379 /// will push one or more such restriction into the
380 /// `transmute_restrictions` vector during `intrinsicck`. They are
381 /// then checked during `trans` by the fn `check_intrinsics`.
382 #[derive(Copy, Clone)]
383 pub struct TransmuteRestriction<'tcx> {
384 /// The span whence the restriction comes.
385 pub span: Span,
386
387 /// The type being transmuted from.
388 pub original_from: Ty<'tcx>,
389
390 /// The type being transmuted to.
391 pub original_to: Ty<'tcx>,
392
393 /// The type being transmuted from, with all type parameters
394 /// substituted for an arbitrary representative. Not to be shown
395 /// to the end user.
396 pub substituted_from: Ty<'tcx>,
397
398 /// The type being transmuted to, with all type parameters
399 /// substituted for an arbitrary representative. Not to be shown
400 /// to the end user.
401 pub substituted_to: Ty<'tcx>,
402
403 /// NodeId of the transmute intrinsic.
404 pub id: NodeId,
405 }
406
407 /// Describes the fragment-state associated with a NodeId.
408 ///
409 /// Currently only unfragmented paths have entries in the table,
410 /// but longer-term this enum is expected to expand to also
411 /// include data for fragmented paths.
412 #[derive(Copy, Clone, Debug)]
413 pub enum FragmentInfo {
414 Moved { var: NodeId, move_expr: NodeId },
415 Assigned { var: NodeId, assign_expr: NodeId, assignee_id: NodeId },
416 }
417
418 // Flags that we track on types. These flags are propagated upwards
419 // through the type during type construction, so that we can quickly
420 // check whether the type has various kinds of types in it without
421 // recursing over the type itself.
422 bitflags! {
423 flags TypeFlags: u32 {
424 const HAS_PARAMS = 1 << 0,
425 const HAS_SELF = 1 << 1,
426 const HAS_TY_INFER = 1 << 2,
427 const HAS_RE_INFER = 1 << 3,
428 const HAS_RE_EARLY_BOUND = 1 << 4,
429 const HAS_FREE_REGIONS = 1 << 5,
430 const HAS_TY_ERR = 1 << 6,
431 const HAS_PROJECTION = 1 << 7,
432 const HAS_TY_CLOSURE = 1 << 8,
433
434 // true if there are "names" of types and regions and so forth
435 // that are local to a particular fn
436 const HAS_LOCAL_NAMES = 1 << 9,
437
438 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
439 TypeFlags::HAS_SELF.bits |
440 TypeFlags::HAS_RE_EARLY_BOUND.bits,
441
442 // Flags representing the nominal content of a type,
443 // computed by FlagsComputation. If you add a new nominal
444 // flag, it should be added here too.
445 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
446 TypeFlags::HAS_SELF.bits |
447 TypeFlags::HAS_TY_INFER.bits |
448 TypeFlags::HAS_RE_INFER.bits |
449 TypeFlags::HAS_RE_EARLY_BOUND.bits |
450 TypeFlags::HAS_FREE_REGIONS.bits |
451 TypeFlags::HAS_TY_ERR.bits |
452 TypeFlags::HAS_PROJECTION.bits |
453 TypeFlags::HAS_TY_CLOSURE.bits |
454 TypeFlags::HAS_LOCAL_NAMES.bits,
455
456 // Caches for type_is_sized, type_moves_by_default
457 const SIZEDNESS_CACHED = 1 << 16,
458 const IS_SIZED = 1 << 17,
459 const MOVENESS_CACHED = 1 << 18,
460 const MOVES_BY_DEFAULT = 1 << 19,
461 }
462 }
463
464 pub struct TyS<'tcx> {
465 pub sty: TypeVariants<'tcx>,
466 pub flags: Cell<TypeFlags>,
467
468 // the maximal depth of any bound regions appearing in this type.
469 region_depth: u32,
470 }
471
472 impl<'tcx> PartialEq for TyS<'tcx> {
473 #[inline]
474 fn eq(&self, other: &TyS<'tcx>) -> bool {
475 // (self as *const _) == (other as *const _)
476 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
477 }
478 }
479 impl<'tcx> Eq for TyS<'tcx> {}
480
481 impl<'tcx> Hash for TyS<'tcx> {
482 fn hash<H: Hasher>(&self, s: &mut H) {
483 (self as *const TyS).hash(s)
484 }
485 }
486
487 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
488
489 impl<'tcx> Encodable for Ty<'tcx> {
490 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
491 cstore::tls::with_encoding_context(s, |ecx, rbml_w| {
492 ecx.encode_ty(rbml_w, *self);
493 Ok(())
494 })
495 }
496 }
497
498 impl<'tcx> Decodable for Ty<'tcx> {
499 fn decode<D: Decoder>(d: &mut D) -> Result<Ty<'tcx>, D::Error> {
500 cstore::tls::with_decoding_context(d, |dcx, rbml_r| {
501 Ok(dcx.decode_ty(rbml_r))
502 })
503 }
504 }
505
506
507 /// Upvars do not get their own node-id. Instead, we use the pair of
508 /// the original var id (that is, the root variable that is referenced
509 /// by the upvar) and the id of the closure expression.
510 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
511 pub struct UpvarId {
512 pub var_id: NodeId,
513 pub closure_expr_id: NodeId,
514 }
515
516 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
517 pub enum BorrowKind {
518 /// Data must be immutable and is aliasable.
519 ImmBorrow,
520
521 /// Data must be immutable but not aliasable. This kind of borrow
522 /// cannot currently be expressed by the user and is used only in
523 /// implicit closure bindings. It is needed when you the closure
524 /// is borrowing or mutating a mutable referent, e.g.:
525 ///
526 /// let x: &mut isize = ...;
527 /// let y = || *x += 5;
528 ///
529 /// If we were to try to translate this closure into a more explicit
530 /// form, we'd encounter an error with the code as written:
531 ///
532 /// struct Env { x: & &mut isize }
533 /// let x: &mut isize = ...;
534 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
535 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
536 ///
537 /// This is then illegal because you cannot mutate a `&mut` found
538 /// in an aliasable location. To solve, you'd have to translate with
539 /// an `&mut` borrow:
540 ///
541 /// struct Env { x: & &mut isize }
542 /// let x: &mut isize = ...;
543 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
544 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
545 ///
546 /// Now the assignment to `**env.x` is legal, but creating a
547 /// mutable pointer to `x` is not because `x` is not mutable. We
548 /// could fix this by declaring `x` as `let mut x`. This is ok in
549 /// user code, if awkward, but extra weird for closures, since the
550 /// borrow is hidden.
551 ///
552 /// So we introduce a "unique imm" borrow -- the referent is
553 /// immutable, but not aliasable. This solves the problem. For
554 /// simplicity, we don't give users the way to express this
555 /// borrow, it's just used when translating closures.
556 UniqueImmBorrow,
557
558 /// Data is mutable and not aliasable.
559 MutBorrow
560 }
561
562 /// Information describing the capture of an upvar. This is computed
563 /// during `typeck`, specifically by `regionck`.
564 #[derive(PartialEq, Clone, Debug, Copy)]
565 pub enum UpvarCapture {
566 /// Upvar is captured by value. This is always true when the
567 /// closure is labeled `move`, but can also be true in other cases
568 /// depending on inference.
569 ByValue,
570
571 /// Upvar is captured by reference.
572 ByRef(UpvarBorrow),
573 }
574
575 #[derive(PartialEq, Clone, Copy)]
576 pub struct UpvarBorrow {
577 /// The kind of borrow: by-ref upvars have access to shared
578 /// immutable borrows, which are not part of the normal language
579 /// syntax.
580 pub kind: BorrowKind,
581
582 /// Region of the resulting reference.
583 pub region: ty::Region,
584 }
585
586 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
587
588 #[derive(Copy, Clone)]
589 pub struct ClosureUpvar<'tcx> {
590 pub def: Def,
591 pub span: Span,
592 pub ty: Ty<'tcx>,
593 }
594
595 #[derive(Clone, Copy, PartialEq)]
596 pub enum IntVarValue {
597 IntType(ast::IntTy),
598 UintType(ast::UintTy),
599 }
600
601 /// Default region to use for the bound of objects that are
602 /// supplied as the value for this type parameter. This is derived
603 /// from `T:'a` annotations appearing in the type definition. If
604 /// this is `None`, then the default is inherited from the
605 /// surrounding context. See RFC #599 for details.
606 #[derive(Copy, Clone)]
607 pub enum ObjectLifetimeDefault {
608 /// Require an explicit annotation. Occurs when multiple
609 /// `T:'a` constraints are found.
610 Ambiguous,
611
612 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
613 BaseDefault,
614
615 /// Use the given region as the default.
616 Specific(Region),
617 }
618
619 #[derive(Clone)]
620 pub struct TypeParameterDef<'tcx> {
621 pub name: Name,
622 pub def_id: DefId,
623 pub space: subst::ParamSpace,
624 pub index: u32,
625 pub default_def_id: DefId, // for use in error reporing about defaults
626 pub default: Option<Ty<'tcx>>,
627 pub object_lifetime_default: ObjectLifetimeDefault,
628 }
629
630 #[derive(Clone)]
631 pub struct RegionParameterDef {
632 pub name: Name,
633 pub def_id: DefId,
634 pub space: subst::ParamSpace,
635 pub index: u32,
636 pub bounds: Vec<ty::Region>,
637 }
638
639 impl RegionParameterDef {
640 pub fn to_early_bound_region(&self) -> ty::Region {
641 ty::ReEarlyBound(ty::EarlyBoundRegion {
642 space: self.space,
643 index: self.index,
644 name: self.name,
645 })
646 }
647 pub fn to_bound_region(&self) -> ty::BoundRegion {
648 ty::BoundRegion::BrNamed(self.def_id, self.name)
649 }
650 }
651
652 /// Information about the formal type/lifetime parameters associated
653 /// with an item or method. Analogous to hir::Generics.
654 #[derive(Clone, Debug)]
655 pub struct Generics<'tcx> {
656 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
657 pub regions: VecPerParamSpace<RegionParameterDef>,
658 }
659
660 impl<'tcx> Generics<'tcx> {
661 pub fn empty() -> Generics<'tcx> {
662 Generics {
663 types: VecPerParamSpace::empty(),
664 regions: VecPerParamSpace::empty(),
665 }
666 }
667
668 pub fn is_empty(&self) -> bool {
669 self.types.is_empty() && self.regions.is_empty()
670 }
671
672 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
673 !self.types.is_empty_in(space)
674 }
675
676 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
677 !self.regions.is_empty_in(space)
678 }
679 }
680
681 /// Bounds on generics.
682 #[derive(Clone)]
683 pub struct GenericPredicates<'tcx> {
684 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
685 }
686
687 impl<'tcx> GenericPredicates<'tcx> {
688 pub fn empty() -> GenericPredicates<'tcx> {
689 GenericPredicates {
690 predicates: VecPerParamSpace::empty(),
691 }
692 }
693
694 pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
695 -> InstantiatedPredicates<'tcx> {
696 InstantiatedPredicates {
697 predicates: self.predicates.subst(tcx, substs),
698 }
699 }
700
701 pub fn instantiate_supertrait(&self,
702 tcx: &ctxt<'tcx>,
703 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
704 -> InstantiatedPredicates<'tcx>
705 {
706 InstantiatedPredicates {
707 predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
708 }
709 }
710 }
711
712 #[derive(Clone, PartialEq, Eq, Hash)]
713 pub enum Predicate<'tcx> {
714 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
715 /// the `Self` type of the trait reference and `A`, `B`, and `C`
716 /// would be the parameters in the `TypeSpace`.
717 Trait(PolyTraitPredicate<'tcx>),
718
719 /// where `T1 == T2`.
720 Equate(PolyEquatePredicate<'tcx>),
721
722 /// where 'a : 'b
723 RegionOutlives(PolyRegionOutlivesPredicate),
724
725 /// where T : 'a
726 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
727
728 /// where <T as TraitRef>::Name == X, approximately.
729 /// See `ProjectionPredicate` struct for details.
730 Projection(PolyProjectionPredicate<'tcx>),
731
732 /// no syntax: T WF
733 WellFormed(Ty<'tcx>),
734
735 /// trait must be object-safe
736 ObjectSafe(DefId),
737 }
738
739 impl<'tcx> Predicate<'tcx> {
740 /// Performs a substitution suitable for going from a
741 /// poly-trait-ref to supertraits that must hold if that
742 /// poly-trait-ref holds. This is slightly different from a normal
743 /// substitution in terms of what happens with bound regions. See
744 /// lengthy comment below for details.
745 pub fn subst_supertrait(&self,
746 tcx: &ctxt<'tcx>,
747 trait_ref: &ty::PolyTraitRef<'tcx>)
748 -> ty::Predicate<'tcx>
749 {
750 // The interaction between HRTB and supertraits is not entirely
751 // obvious. Let me walk you (and myself) through an example.
752 //
753 // Let's start with an easy case. Consider two traits:
754 //
755 // trait Foo<'a> : Bar<'a,'a> { }
756 // trait Bar<'b,'c> { }
757 //
758 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
759 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
760 // knew that `Foo<'x>` (for any 'x) then we also know that
761 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
762 // normal substitution.
763 //
764 // In terms of why this is sound, the idea is that whenever there
765 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
766 // holds. So if there is an impl of `T:Foo<'a>` that applies to
767 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
768 // `'a`.
769 //
770 // Another example to be careful of is this:
771 //
772 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
773 // trait Bar1<'b,'c> { }
774 //
775 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
776 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
777 // reason is similar to the previous example: any impl of
778 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
779 // basically we would want to collapse the bound lifetimes from
780 // the input (`trait_ref`) and the supertraits.
781 //
782 // To achieve this in practice is fairly straightforward. Let's
783 // consider the more complicated scenario:
784 //
785 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
786 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
787 // where both `'x` and `'b` would have a DB index of 1.
788 // The substitution from the input trait-ref is therefore going to be
789 // `'a => 'x` (where `'x` has a DB index of 1).
790 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
791 // early-bound parameter and `'b' is a late-bound parameter with a
792 // DB index of 1.
793 // - If we replace `'a` with `'x` from the input, it too will have
794 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
795 // just as we wanted.
796 //
797 // There is only one catch. If we just apply the substitution `'a
798 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
799 // adjust the DB index because we substituting into a binder (it
800 // tries to be so smart...) resulting in `for<'x> for<'b>
801 // Bar1<'x,'b>` (we have no syntax for this, so use your
802 // imagination). Basically the 'x will have DB index of 2 and 'b
803 // will have DB index of 1. Not quite what we want. So we apply
804 // the substitution to the *contents* of the trait reference,
805 // rather than the trait reference itself (put another way, the
806 // substitution code expects equal binding levels in the values
807 // from the substitution and the value being substituted into, and
808 // this trick achieves that).
809
810 let substs = &trait_ref.0.substs;
811 match *self {
812 Predicate::Trait(ty::Binder(ref data)) =>
813 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
814 Predicate::Equate(ty::Binder(ref data)) =>
815 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
816 Predicate::RegionOutlives(ty::Binder(ref data)) =>
817 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
818 Predicate::TypeOutlives(ty::Binder(ref data)) =>
819 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
820 Predicate::Projection(ty::Binder(ref data)) =>
821 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
822 Predicate::WellFormed(data) =>
823 Predicate::WellFormed(data.subst(tcx, substs)),
824 Predicate::ObjectSafe(trait_def_id) =>
825 Predicate::ObjectSafe(trait_def_id),
826 }
827 }
828 }
829
830 #[derive(Clone, PartialEq, Eq, Hash)]
831 pub struct TraitPredicate<'tcx> {
832 pub trait_ref: TraitRef<'tcx>
833 }
834 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
835
836 impl<'tcx> TraitPredicate<'tcx> {
837 pub fn def_id(&self) -> DefId {
838 self.trait_ref.def_id
839 }
840
841 /// Creates the dep-node for selecting/evaluating this trait reference.
842 fn dep_node(&self) -> DepNode {
843 DepNode::TraitSelect(self.def_id())
844 }
845
846 pub fn input_types(&self) -> &[Ty<'tcx>] {
847 self.trait_ref.substs.types.as_slice()
848 }
849
850 pub fn self_ty(&self) -> Ty<'tcx> {
851 self.trait_ref.self_ty()
852 }
853 }
854
855 impl<'tcx> PolyTraitPredicate<'tcx> {
856 pub fn def_id(&self) -> DefId {
857 // ok to skip binder since trait def-id does not care about regions
858 self.0.def_id()
859 }
860
861 pub fn dep_node(&self) -> DepNode {
862 // ok to skip binder since depnode does not care about regions
863 self.0.dep_node()
864 }
865 }
866
867 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
868 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
869 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
870
871 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
872 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
873 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
874 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
875 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
876
877 /// This kind of predicate has no *direct* correspondent in the
878 /// syntax, but it roughly corresponds to the syntactic forms:
879 ///
880 /// 1. `T : TraitRef<..., Item=Type>`
881 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
882 ///
883 /// In particular, form #1 is "desugared" to the combination of a
884 /// normal trait predicate (`T : TraitRef<...>`) and one of these
885 /// predicates. Form #2 is a broader form in that it also permits
886 /// equality between arbitrary types. Processing an instance of Form
887 /// #2 eventually yields one of these `ProjectionPredicate`
888 /// instances to normalize the LHS.
889 #[derive(Clone, PartialEq, Eq, Hash)]
890 pub struct ProjectionPredicate<'tcx> {
891 pub projection_ty: ProjectionTy<'tcx>,
892 pub ty: Ty<'tcx>,
893 }
894
895 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
896
897 impl<'tcx> PolyProjectionPredicate<'tcx> {
898 pub fn item_name(&self) -> Name {
899 self.0.projection_ty.item_name // safe to skip the binder to access a name
900 }
901
902 pub fn sort_key(&self) -> (DefId, Name) {
903 self.0.projection_ty.sort_key()
904 }
905 }
906
907 pub trait ToPolyTraitRef<'tcx> {
908 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
909 }
910
911 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
912 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
913 assert!(!self.has_escaping_regions());
914 ty::Binder(self.clone())
915 }
916 }
917
918 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
919 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
920 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
921 }
922 }
923
924 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
925 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
926 // Note: unlike with TraitRef::to_poly_trait_ref(),
927 // self.0.trait_ref is permitted to have escaping regions.
928 // This is because here `self` has a `Binder` and so does our
929 // return value, so we are preserving the number of binding
930 // levels.
931 ty::Binder(self.0.projection_ty.trait_ref)
932 }
933 }
934
935 pub trait ToPredicate<'tcx> {
936 fn to_predicate(&self) -> Predicate<'tcx>;
937 }
938
939 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
940 fn to_predicate(&self) -> Predicate<'tcx> {
941 // we're about to add a binder, so let's check that we don't
942 // accidentally capture anything, or else that might be some
943 // weird debruijn accounting.
944 assert!(!self.has_escaping_regions());
945
946 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
947 trait_ref: self.clone()
948 }))
949 }
950 }
951
952 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
953 fn to_predicate(&self) -> Predicate<'tcx> {
954 ty::Predicate::Trait(self.to_poly_trait_predicate())
955 }
956 }
957
958 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
959 fn to_predicate(&self) -> Predicate<'tcx> {
960 Predicate::Equate(self.clone())
961 }
962 }
963
964 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
965 fn to_predicate(&self) -> Predicate<'tcx> {
966 Predicate::RegionOutlives(self.clone())
967 }
968 }
969
970 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
971 fn to_predicate(&self) -> Predicate<'tcx> {
972 Predicate::TypeOutlives(self.clone())
973 }
974 }
975
976 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
977 fn to_predicate(&self) -> Predicate<'tcx> {
978 Predicate::Projection(self.clone())
979 }
980 }
981
982 impl<'tcx> Predicate<'tcx> {
983 /// Iterates over the types in this predicate. Note that in all
984 /// cases this is skipping over a binder, so late-bound regions
985 /// with depth 0 are bound by the predicate.
986 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
987 let vec: Vec<_> = match *self {
988 ty::Predicate::Trait(ref data) => {
989 data.0.trait_ref.substs.types.as_slice().to_vec()
990 }
991 ty::Predicate::Equate(ty::Binder(ref data)) => {
992 vec![data.0, data.1]
993 }
994 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
995 vec![data.0]
996 }
997 ty::Predicate::RegionOutlives(..) => {
998 vec![]
999 }
1000 ty::Predicate::Projection(ref data) => {
1001 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
1002 trait_inputs.iter()
1003 .cloned()
1004 .chain(Some(data.0.ty))
1005 .collect()
1006 }
1007 ty::Predicate::WellFormed(data) => {
1008 vec![data]
1009 }
1010 ty::Predicate::ObjectSafe(_trait_def_id) => {
1011 vec![]
1012 }
1013 };
1014
1015 // The only reason to collect into a vector here is that I was
1016 // too lazy to make the full (somewhat complicated) iterator
1017 // type that would be needed here. But I wanted this fn to
1018 // return an iterator conceptually, rather than a `Vec`, so as
1019 // to be closer to `Ty::walk`.
1020 vec.into_iter()
1021 }
1022
1023 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1024 match *self {
1025 Predicate::Trait(ref t) => {
1026 Some(t.to_poly_trait_ref())
1027 }
1028 Predicate::Projection(..) |
1029 Predicate::Equate(..) |
1030 Predicate::RegionOutlives(..) |
1031 Predicate::WellFormed(..) |
1032 Predicate::ObjectSafe(..) |
1033 Predicate::TypeOutlives(..) => {
1034 None
1035 }
1036 }
1037 }
1038 }
1039
1040 /// Represents the bounds declared on a particular set of type
1041 /// parameters. Should eventually be generalized into a flag list of
1042 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1043 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1044 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1045 /// the `GenericPredicates` are expressed in terms of the bound type
1046 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1047 /// represented a set of bounds for some particular instantiation,
1048 /// meaning that the generic parameters have been substituted with
1049 /// their values.
1050 ///
1051 /// Example:
1052 ///
1053 /// struct Foo<T,U:Bar<T>> { ... }
1054 ///
1055 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1056 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1057 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1058 /// [usize:Bar<isize>]]`.
1059 #[derive(Clone)]
1060 pub struct InstantiatedPredicates<'tcx> {
1061 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
1062 }
1063
1064 impl<'tcx> InstantiatedPredicates<'tcx> {
1065 pub fn empty() -> InstantiatedPredicates<'tcx> {
1066 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
1067 }
1068
1069 pub fn is_empty(&self) -> bool {
1070 self.predicates.is_empty()
1071 }
1072 }
1073
1074 impl<'tcx> TraitRef<'tcx> {
1075 pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
1076 TraitRef { def_id: def_id, substs: substs }
1077 }
1078
1079 pub fn self_ty(&self) -> Ty<'tcx> {
1080 self.substs.self_ty().unwrap()
1081 }
1082
1083 pub fn input_types(&self) -> &[Ty<'tcx>] {
1084 // Select only the "input types" from a trait-reference. For
1085 // now this is all the types that appear in the
1086 // trait-reference, but it should eventually exclude
1087 // associated types.
1088 self.substs.types.as_slice()
1089 }
1090 }
1091
1092 /// When type checking, we use the `ParameterEnvironment` to track
1093 /// details about the type/lifetime parameters that are in scope.
1094 /// It primarily stores the bounds information.
1095 ///
1096 /// Note: This information might seem to be redundant with the data in
1097 /// `tcx.ty_param_defs`, but it is not. That table contains the
1098 /// parameter definitions from an "outside" perspective, but this
1099 /// struct will contain the bounds for a parameter as seen from inside
1100 /// the function body. Currently the only real distinction is that
1101 /// bound lifetime parameters are replaced with free ones, but in the
1102 /// future I hope to refine the representation of types so as to make
1103 /// more distinctions clearer.
1104 #[derive(Clone)]
1105 pub struct ParameterEnvironment<'a, 'tcx:'a> {
1106 pub tcx: &'a ctxt<'tcx>,
1107
1108 /// See `construct_free_substs` for details.
1109 pub free_substs: Substs<'tcx>,
1110
1111 /// Each type parameter has an implicit region bound that
1112 /// indicates it must outlive at least the function body (the user
1113 /// may specify stronger requirements). This field indicates the
1114 /// region of the callee.
1115 pub implicit_region_bound: ty::Region,
1116
1117 /// Obligations that the caller must satisfy. This is basically
1118 /// the set of bounds on the in-scope type parameters, translated
1119 /// into Obligations, and elaborated and normalized.
1120 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
1121
1122 /// Caches the results of trait selection. This cache is used
1123 /// for things that have to do with the parameters in scope.
1124 pub selection_cache: traits::SelectionCache<'tcx>,
1125
1126 /// Caches the results of trait evaluation.
1127 pub evaluation_cache: traits::EvaluationCache<'tcx>,
1128
1129 /// Scope that is attached to free regions for this scope. This
1130 /// is usually the id of the fn body, but for more abstract scopes
1131 /// like structs we often use the node-id of the struct.
1132 ///
1133 /// FIXME(#3696). It would be nice to refactor so that free
1134 /// regions don't have this implicit scope and instead introduce
1135 /// relationships in the environment.
1136 pub free_id_outlive: CodeExtent,
1137 }
1138
1139 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
1140 pub fn with_caller_bounds(&self,
1141 caller_bounds: Vec<ty::Predicate<'tcx>>)
1142 -> ParameterEnvironment<'a,'tcx>
1143 {
1144 ParameterEnvironment {
1145 tcx: self.tcx,
1146 free_substs: self.free_substs.clone(),
1147 implicit_region_bound: self.implicit_region_bound,
1148 caller_bounds: caller_bounds,
1149 selection_cache: traits::SelectionCache::new(),
1150 evaluation_cache: traits::EvaluationCache::new(),
1151 free_id_outlive: self.free_id_outlive,
1152 }
1153 }
1154
1155 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
1156 match cx.map.find(id) {
1157 Some(ast_map::NodeImplItem(ref impl_item)) => {
1158 match impl_item.node {
1159 hir::ImplItemKind::Type(_) => {
1160 // associated types don't have their own entry (for some reason),
1161 // so for now just grab environment for the impl
1162 let impl_id = cx.map.get_parent(id);
1163 let impl_def_id = cx.map.local_def_id(impl_id);
1164 let scheme = cx.lookup_item_type(impl_def_id);
1165 let predicates = cx.lookup_predicates(impl_def_id);
1166 cx.construct_parameter_environment(impl_item.span,
1167 &scheme.generics,
1168 &predicates,
1169 cx.region_maps.item_extent(id))
1170 }
1171 hir::ImplItemKind::Const(_, _) => {
1172 let def_id = cx.map.local_def_id(id);
1173 let scheme = cx.lookup_item_type(def_id);
1174 let predicates = cx.lookup_predicates(def_id);
1175 cx.construct_parameter_environment(impl_item.span,
1176 &scheme.generics,
1177 &predicates,
1178 cx.region_maps.item_extent(id))
1179 }
1180 hir::ImplItemKind::Method(_, ref body) => {
1181 let method_def_id = cx.map.local_def_id(id);
1182 match cx.impl_or_trait_item(method_def_id) {
1183 MethodTraitItem(ref method_ty) => {
1184 let method_generics = &method_ty.generics;
1185 let method_bounds = &method_ty.predicates;
1186 cx.construct_parameter_environment(
1187 impl_item.span,
1188 method_generics,
1189 method_bounds,
1190 cx.region_maps.call_site_extent(id, body.id))
1191 }
1192 _ => {
1193 cx.sess
1194 .bug("ParameterEnvironment::for_item(): \
1195 got non-method item from impl method?!")
1196 }
1197 }
1198 }
1199 }
1200 }
1201 Some(ast_map::NodeTraitItem(trait_item)) => {
1202 match trait_item.node {
1203 hir::TypeTraitItem(..) => {
1204 // associated types don't have their own entry (for some reason),
1205 // so for now just grab environment for the trait
1206 let trait_id = cx.map.get_parent(id);
1207 let trait_def_id = cx.map.local_def_id(trait_id);
1208 let trait_def = cx.lookup_trait_def(trait_def_id);
1209 let predicates = cx.lookup_predicates(trait_def_id);
1210 cx.construct_parameter_environment(trait_item.span,
1211 &trait_def.generics,
1212 &predicates,
1213 cx.region_maps.item_extent(id))
1214 }
1215 hir::ConstTraitItem(..) => {
1216 let def_id = cx.map.local_def_id(id);
1217 let scheme = cx.lookup_item_type(def_id);
1218 let predicates = cx.lookup_predicates(def_id);
1219 cx.construct_parameter_environment(trait_item.span,
1220 &scheme.generics,
1221 &predicates,
1222 cx.region_maps.item_extent(id))
1223 }
1224 hir::MethodTraitItem(_, ref body) => {
1225 // Use call-site for extent (unless this is a
1226 // trait method with no default; then fallback
1227 // to the method id).
1228 let method_def_id = cx.map.local_def_id(id);
1229 match cx.impl_or_trait_item(method_def_id) {
1230 MethodTraitItem(ref method_ty) => {
1231 let method_generics = &method_ty.generics;
1232 let method_bounds = &method_ty.predicates;
1233 let extent = if let Some(ref body) = *body {
1234 // default impl: use call_site extent as free_id_outlive bound.
1235 cx.region_maps.call_site_extent(id, body.id)
1236 } else {
1237 // no default impl: use item extent as free_id_outlive bound.
1238 cx.region_maps.item_extent(id)
1239 };
1240 cx.construct_parameter_environment(
1241 trait_item.span,
1242 method_generics,
1243 method_bounds,
1244 extent)
1245 }
1246 _ => {
1247 cx.sess
1248 .bug("ParameterEnvironment::for_item(): \
1249 got non-method item from provided \
1250 method?!")
1251 }
1252 }
1253 }
1254 }
1255 }
1256 Some(ast_map::NodeItem(item)) => {
1257 match item.node {
1258 hir::ItemFn(_, _, _, _, _, ref body) => {
1259 // We assume this is a function.
1260 let fn_def_id = cx.map.local_def_id(id);
1261 let fn_scheme = cx.lookup_item_type(fn_def_id);
1262 let fn_predicates = cx.lookup_predicates(fn_def_id);
1263
1264 cx.construct_parameter_environment(item.span,
1265 &fn_scheme.generics,
1266 &fn_predicates,
1267 cx.region_maps.call_site_extent(id,
1268 body.id))
1269 }
1270 hir::ItemEnum(..) |
1271 hir::ItemStruct(..) |
1272 hir::ItemImpl(..) |
1273 hir::ItemConst(..) |
1274 hir::ItemStatic(..) => {
1275 let def_id = cx.map.local_def_id(id);
1276 let scheme = cx.lookup_item_type(def_id);
1277 let predicates = cx.lookup_predicates(def_id);
1278 cx.construct_parameter_environment(item.span,
1279 &scheme.generics,
1280 &predicates,
1281 cx.region_maps.item_extent(id))
1282 }
1283 hir::ItemTrait(..) => {
1284 let def_id = cx.map.local_def_id(id);
1285 let trait_def = cx.lookup_trait_def(def_id);
1286 let predicates = cx.lookup_predicates(def_id);
1287 cx.construct_parameter_environment(item.span,
1288 &trait_def.generics,
1289 &predicates,
1290 cx.region_maps.item_extent(id))
1291 }
1292 _ => {
1293 cx.sess.span_bug(item.span,
1294 "ParameterEnvironment::from_item():
1295 can't create a parameter \
1296 environment for this kind of item")
1297 }
1298 }
1299 }
1300 Some(ast_map::NodeExpr(..)) => {
1301 // This is a convenience to allow closures to work.
1302 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
1303 }
1304 _ => {
1305 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
1306 `{}` is not an item",
1307 cx.map.node_to_string(id)))
1308 }
1309 }
1310 }
1311 }
1312
1313 /// A "type scheme", in ML terminology, is a type combined with some
1314 /// set of generic types that the type is, well, generic over. In Rust
1315 /// terms, it is the "type" of a fn item or struct -- this type will
1316 /// include various generic parameters that must be substituted when
1317 /// the item/struct is referenced. That is called converting the type
1318 /// scheme to a monotype.
1319 ///
1320 /// - `generics`: the set of type parameters and their bounds
1321 /// - `ty`: the base types, which may reference the parameters defined
1322 /// in `generics`
1323 ///
1324 /// Note that TypeSchemes are also sometimes called "polytypes" (and
1325 /// in fact this struct used to carry that name, so you may find some
1326 /// stray references in a comment or something). We try to reserve the
1327 /// "poly" prefix to refer to higher-ranked things, as in
1328 /// `PolyTraitRef`.
1329 ///
1330 /// Note that each item also comes with predicates, see
1331 /// `lookup_predicates`.
1332 #[derive(Clone, Debug)]
1333 pub struct TypeScheme<'tcx> {
1334 pub generics: Generics<'tcx>,
1335 pub ty: Ty<'tcx>,
1336 }
1337
1338 bitflags! {
1339 flags AdtFlags: u32 {
1340 const NO_ADT_FLAGS = 0,
1341 const IS_ENUM = 1 << 0,
1342 const IS_DTORCK = 1 << 1, // is this a dtorck type?
1343 const IS_DTORCK_VALID = 1 << 2,
1344 const IS_PHANTOM_DATA = 1 << 3,
1345 const IS_SIMD = 1 << 4,
1346 const IS_FUNDAMENTAL = 1 << 5,
1347 const IS_NO_DROP_FLAG = 1 << 6,
1348 }
1349 }
1350
1351 pub type AdtDef<'tcx> = &'tcx AdtDefData<'tcx, 'static>;
1352 pub type VariantDef<'tcx> = &'tcx VariantDefData<'tcx, 'static>;
1353 pub type FieldDef<'tcx> = &'tcx FieldDefData<'tcx, 'static>;
1354
1355 // See comment on AdtDefData for explanation
1356 pub type AdtDefMaster<'tcx> = &'tcx AdtDefData<'tcx, 'tcx>;
1357 pub type VariantDefMaster<'tcx> = &'tcx VariantDefData<'tcx, 'tcx>;
1358 pub type FieldDefMaster<'tcx> = &'tcx FieldDefData<'tcx, 'tcx>;
1359
1360 pub struct VariantDefData<'tcx, 'container: 'tcx> {
1361 /// The variant's DefId. If this is a tuple-like struct,
1362 /// this is the DefId of the struct's ctor.
1363 pub did: DefId,
1364 pub name: Name, // struct's name if this is a struct
1365 pub disr_val: Disr,
1366 pub fields: Vec<FieldDefData<'tcx, 'container>>,
1367 pub kind: VariantKind,
1368 }
1369
1370 pub struct FieldDefData<'tcx, 'container: 'tcx> {
1371 /// The field's DefId. NOTE: the fields of tuple-like enum variants
1372 /// are not real items, and don't have entries in tcache etc.
1373 pub did: DefId,
1374 /// special_idents::unnamed_field.name
1375 /// if this is a tuple-like field
1376 pub name: Name,
1377 pub vis: hir::Visibility,
1378 /// TyIVar is used here to allow for variance (see the doc at
1379 /// AdtDefData).
1380 ///
1381 /// Note: direct accesses to `ty` must also add dep edges.
1382 ty: ivar::TyIVar<'tcx, 'container>
1383 }
1384
1385 /// The definition of an abstract data type - a struct or enum.
1386 ///
1387 /// These are all interned (by intern_adt_def) into the adt_defs
1388 /// table.
1389 ///
1390 /// Because of the possibility of nested tcx-s, this type
1391 /// needs 2 lifetimes: the traditional variant lifetime ('tcx)
1392 /// bounding the lifetime of the inner types is of course necessary.
1393 /// However, it is not sufficient - types from a child tcx must
1394 /// not be leaked into the master tcx by being stored in an AdtDefData.
1395 ///
1396 /// The 'container lifetime ensures that by outliving the container
1397 /// tcx and preventing shorter-lived types from being inserted. When
1398 /// write access is not needed, the 'container lifetime can be
1399 /// erased to 'static, which can be done by the AdtDef wrapper.
1400 pub struct AdtDefData<'tcx, 'container: 'tcx> {
1401 pub did: DefId,
1402 pub variants: Vec<VariantDefData<'tcx, 'container>>,
1403 destructor: Cell<Option<DefId>>,
1404 flags: Cell<AdtFlags>,
1405 }
1406
1407 impl<'tcx, 'container> PartialEq for AdtDefData<'tcx, 'container> {
1408 // AdtDefData are always interned and this is part of TyS equality
1409 #[inline]
1410 fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
1411 }
1412
1413 impl<'tcx, 'container> Eq for AdtDefData<'tcx, 'container> {}
1414
1415 impl<'tcx, 'container> Hash for AdtDefData<'tcx, 'container> {
1416 #[inline]
1417 fn hash<H: Hasher>(&self, s: &mut H) {
1418 (self as *const AdtDefData).hash(s)
1419 }
1420 }
1421
1422 impl<'tcx> Encodable for AdtDef<'tcx> {
1423 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1424 self.did.encode(s)
1425 }
1426 }
1427
1428 impl<'tcx> Decodable for AdtDef<'tcx> {
1429 fn decode<D: Decoder>(d: &mut D) -> Result<AdtDef<'tcx>, D::Error> {
1430 let def_id: DefId = try!{ Decodable::decode(d) };
1431
1432 cstore::tls::with_decoding_context(d, |dcx, _| {
1433 let def_id = dcx.translate_def_id(def_id);
1434 Ok(dcx.tcx().lookup_adt_def(def_id))
1435 })
1436 }
1437 }
1438
1439
1440 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
1441 pub enum AdtKind { Struct, Enum }
1442
1443 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1444 pub enum VariantKind { Struct, Tuple, Unit }
1445
1446 impl VariantKind {
1447 pub fn from_variant_data(vdata: &hir::VariantData) -> Self {
1448 match *vdata {
1449 hir::VariantData::Struct(..) => VariantKind::Struct,
1450 hir::VariantData::Tuple(..) => VariantKind::Tuple,
1451 hir::VariantData::Unit(..) => VariantKind::Unit,
1452 }
1453 }
1454 }
1455
1456 impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
1457 fn new(tcx: &ctxt<'tcx>,
1458 did: DefId,
1459 kind: AdtKind,
1460 variants: Vec<VariantDefData<'tcx, 'container>>) -> Self {
1461 let mut flags = AdtFlags::NO_ADT_FLAGS;
1462 let attrs = tcx.get_attrs(did);
1463 if attr::contains_name(&attrs, "fundamental") {
1464 flags = flags | AdtFlags::IS_FUNDAMENTAL;
1465 }
1466 if attr::contains_name(&attrs, "unsafe_no_drop_flag") {
1467 flags = flags | AdtFlags::IS_NO_DROP_FLAG;
1468 }
1469 if tcx.lookup_simd(did) {
1470 flags = flags | AdtFlags::IS_SIMD;
1471 }
1472 if Some(did) == tcx.lang_items.phantom_data() {
1473 flags = flags | AdtFlags::IS_PHANTOM_DATA;
1474 }
1475 if let AdtKind::Enum = kind {
1476 flags = flags | AdtFlags::IS_ENUM;
1477 }
1478 AdtDefData {
1479 did: did,
1480 variants: variants,
1481 flags: Cell::new(flags),
1482 destructor: Cell::new(None)
1483 }
1484 }
1485
1486 fn calculate_dtorck(&'tcx self, tcx: &ctxt<'tcx>) {
1487 if tcx.is_adt_dtorck(self) {
1488 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK);
1489 }
1490 self.flags.set(self.flags.get() | AdtFlags::IS_DTORCK_VALID)
1491 }
1492
1493 /// Returns the kind of the ADT - Struct or Enum.
1494 #[inline]
1495 pub fn adt_kind(&self) -> AdtKind {
1496 if self.flags.get().intersects(AdtFlags::IS_ENUM) {
1497 AdtKind::Enum
1498 } else {
1499 AdtKind::Struct
1500 }
1501 }
1502
1503 /// Returns whether this is a dtorck type. If this returns
1504 /// true, this type being safe for destruction requires it to be
1505 /// alive; Otherwise, only the contents are required to be.
1506 #[inline]
1507 pub fn is_dtorck(&'tcx self, tcx: &ctxt<'tcx>) -> bool {
1508 if !self.flags.get().intersects(AdtFlags::IS_DTORCK_VALID) {
1509 self.calculate_dtorck(tcx)
1510 }
1511 self.flags.get().intersects(AdtFlags::IS_DTORCK)
1512 }
1513
1514 /// Returns whether this type is #[fundamental] for the purposes
1515 /// of coherence checking.
1516 #[inline]
1517 pub fn is_fundamental(&self) -> bool {
1518 self.flags.get().intersects(AdtFlags::IS_FUNDAMENTAL)
1519 }
1520
1521 #[inline]
1522 pub fn is_simd(&self) -> bool {
1523 self.flags.get().intersects(AdtFlags::IS_SIMD)
1524 }
1525
1526 /// Returns true if this is PhantomData<T>.
1527 #[inline]
1528 pub fn is_phantom_data(&self) -> bool {
1529 self.flags.get().intersects(AdtFlags::IS_PHANTOM_DATA)
1530 }
1531
1532 /// Returns whether this type has a destructor.
1533 pub fn has_dtor(&self) -> bool {
1534 match self.dtor_kind() {
1535 NoDtor => false,
1536 TraitDtor(..) => true
1537 }
1538 }
1539
1540 /// Asserts this is a struct and returns the struct's unique
1541 /// variant.
1542 pub fn struct_variant(&self) -> &VariantDefData<'tcx, 'container> {
1543 assert!(self.adt_kind() == AdtKind::Struct);
1544 &self.variants[0]
1545 }
1546
1547 #[inline]
1548 pub fn type_scheme(&self, tcx: &ctxt<'tcx>) -> TypeScheme<'tcx> {
1549 tcx.lookup_item_type(self.did)
1550 }
1551
1552 #[inline]
1553 pub fn predicates(&self, tcx: &ctxt<'tcx>) -> GenericPredicates<'tcx> {
1554 tcx.lookup_predicates(self.did)
1555 }
1556
1557 /// Returns an iterator over all fields contained
1558 /// by this ADT.
1559 #[inline]
1560 pub fn all_fields(&self) ->
1561 iter::FlatMap<
1562 slice::Iter<VariantDefData<'tcx, 'container>>,
1563 slice::Iter<FieldDefData<'tcx, 'container>>,
1564 for<'s> fn(&'s VariantDefData<'tcx, 'container>)
1565 -> slice::Iter<'s, FieldDefData<'tcx, 'container>>
1566 > {
1567 self.variants.iter().flat_map(VariantDefData::fields_iter)
1568 }
1569
1570 #[inline]
1571 pub fn is_empty(&self) -> bool {
1572 self.variants.is_empty()
1573 }
1574
1575 #[inline]
1576 pub fn is_univariant(&self) -> bool {
1577 self.variants.len() == 1
1578 }
1579
1580 pub fn is_payloadfree(&self) -> bool {
1581 !self.variants.is_empty() &&
1582 self.variants.iter().all(|v| v.fields.is_empty())
1583 }
1584
1585 pub fn variant_with_id(&self, vid: DefId) -> &VariantDefData<'tcx, 'container> {
1586 self.variants
1587 .iter()
1588 .find(|v| v.did == vid)
1589 .expect("variant_with_id: unknown variant")
1590 }
1591
1592 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
1593 self.variants
1594 .iter()
1595 .position(|v| v.did == vid)
1596 .expect("variant_index_with_id: unknown variant")
1597 }
1598
1599 pub fn variant_of_def(&self, def: Def) -> &VariantDefData<'tcx, 'container> {
1600 match def {
1601 Def::Variant(_, vid) => self.variant_with_id(vid),
1602 Def::Struct(..) | Def::TyAlias(..) => self.struct_variant(),
1603 _ => panic!("unexpected def {:?} in variant_of_def", def)
1604 }
1605 }
1606
1607 pub fn destructor(&self) -> Option<DefId> {
1608 self.destructor.get()
1609 }
1610
1611 pub fn set_destructor(&self, dtor: DefId) {
1612 self.destructor.set(Some(dtor));
1613 }
1614
1615 pub fn dtor_kind(&self) -> DtorKind {
1616 match self.destructor.get() {
1617 Some(_) => {
1618 TraitDtor(!self.flags.get().intersects(AdtFlags::IS_NO_DROP_FLAG))
1619 }
1620 None => NoDtor,
1621 }
1622 }
1623 }
1624
1625 impl<'tcx, 'container> VariantDefData<'tcx, 'container> {
1626 #[inline]
1627 fn fields_iter(&self) -> slice::Iter<FieldDefData<'tcx, 'container>> {
1628 self.fields.iter()
1629 }
1630
1631 pub fn kind(&self) -> VariantKind {
1632 self.kind
1633 }
1634
1635 pub fn is_tuple_struct(&self) -> bool {
1636 self.kind() == VariantKind::Tuple
1637 }
1638
1639 #[inline]
1640 pub fn find_field_named(&self,
1641 name: ast::Name)
1642 -> Option<&FieldDefData<'tcx, 'container>> {
1643 self.fields.iter().find(|f| f.name == name)
1644 }
1645
1646 #[inline]
1647 pub fn index_of_field_named(&self,
1648 name: ast::Name)
1649 -> Option<usize> {
1650 self.fields.iter().position(|f| f.name == name)
1651 }
1652
1653 #[inline]
1654 pub fn field_named(&self, name: ast::Name) -> &FieldDefData<'tcx, 'container> {
1655 self.find_field_named(name).unwrap()
1656 }
1657 }
1658
1659 impl<'tcx, 'container> FieldDefData<'tcx, 'container> {
1660 pub fn new(did: DefId,
1661 name: Name,
1662 vis: hir::Visibility) -> Self {
1663 FieldDefData {
1664 did: did,
1665 name: name,
1666 vis: vis,
1667 ty: ivar::TyIVar::new()
1668 }
1669 }
1670
1671 pub fn ty(&self, tcx: &ctxt<'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
1672 self.unsubst_ty().subst(tcx, subst)
1673 }
1674
1675 pub fn unsubst_ty(&self) -> Ty<'tcx> {
1676 self.ty.unwrap(DepNode::FieldTy(self.did))
1677 }
1678
1679 pub fn fulfill_ty(&self, ty: Ty<'container>) {
1680 self.ty.fulfill(DepNode::FieldTy(self.did), ty);
1681 }
1682 }
1683
1684 /// Records the substitutions used to translate the polytype for an
1685 /// item into the monotype of an item reference.
1686 #[derive(Clone)]
1687 pub struct ItemSubsts<'tcx> {
1688 pub substs: Substs<'tcx>,
1689 }
1690
1691 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
1692 pub enum ClosureKind {
1693 // Warning: Ordering is significant here! The ordering is chosen
1694 // because the trait Fn is a subtrait of FnMut and so in turn, and
1695 // hence we order it so that Fn < FnMut < FnOnce.
1696 FnClosureKind,
1697 FnMutClosureKind,
1698 FnOnceClosureKind,
1699 }
1700
1701 impl ClosureKind {
1702 pub fn trait_did(&self, cx: &ctxt) -> DefId {
1703 let result = match *self {
1704 FnClosureKind => cx.lang_items.require(FnTraitLangItem),
1705 FnMutClosureKind => {
1706 cx.lang_items.require(FnMutTraitLangItem)
1707 }
1708 FnOnceClosureKind => {
1709 cx.lang_items.require(FnOnceTraitLangItem)
1710 }
1711 };
1712 match result {
1713 Ok(trait_did) => trait_did,
1714 Err(err) => cx.sess.fatal(&err[..]),
1715 }
1716 }
1717
1718 /// True if this a type that impls this closure kind
1719 /// must also implement `other`.
1720 pub fn extends(self, other: ty::ClosureKind) -> bool {
1721 match (self, other) {
1722 (FnClosureKind, FnClosureKind) => true,
1723 (FnClosureKind, FnMutClosureKind) => true,
1724 (FnClosureKind, FnOnceClosureKind) => true,
1725 (FnMutClosureKind, FnMutClosureKind) => true,
1726 (FnMutClosureKind, FnOnceClosureKind) => true,
1727 (FnOnceClosureKind, FnOnceClosureKind) => true,
1728 _ => false,
1729 }
1730 }
1731 }
1732
1733 impl<'tcx> TyS<'tcx> {
1734 /// Iterator that walks `self` and any types reachable from
1735 /// `self`, in depth-first order. Note that just walks the types
1736 /// that appear in `self`, it does not descend into the fields of
1737 /// structs or variants. For example:
1738 ///
1739 /// ```notrust
1740 /// isize => { isize }
1741 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
1742 /// [isize] => { [isize], isize }
1743 /// ```
1744 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
1745 TypeWalker::new(self)
1746 }
1747
1748 /// Iterator that walks the immediate children of `self`. Hence
1749 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
1750 /// (but not `i32`, like `walk`).
1751 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
1752 walk::walk_shallow(self)
1753 }
1754
1755 /// Walks `ty` and any types appearing within `ty`, invoking the
1756 /// callback `f` on each type. If the callback returns false, then the
1757 /// children of the current type are ignored.
1758 ///
1759 /// Note: prefer `ty.walk()` where possible.
1760 pub fn maybe_walk<F>(&'tcx self, mut f: F)
1761 where F : FnMut(Ty<'tcx>) -> bool
1762 {
1763 let mut walker = self.walk();
1764 while let Some(ty) = walker.next() {
1765 if !f(ty) {
1766 walker.skip_current_subtree();
1767 }
1768 }
1769 }
1770 }
1771
1772 impl<'tcx> ItemSubsts<'tcx> {
1773 pub fn empty() -> ItemSubsts<'tcx> {
1774 ItemSubsts { substs: Substs::empty() }
1775 }
1776
1777 pub fn is_noop(&self) -> bool {
1778 self.substs.is_noop()
1779 }
1780 }
1781
1782 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1783 pub enum LvaluePreference {
1784 PreferMutLvalue,
1785 NoPreference
1786 }
1787
1788 impl LvaluePreference {
1789 pub fn from_mutbl(m: hir::Mutability) -> Self {
1790 match m {
1791 hir::MutMutable => PreferMutLvalue,
1792 hir::MutImmutable => NoPreference,
1793 }
1794 }
1795 }
1796
1797 /// Helper for looking things up in the various maps that are populated during
1798 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
1799 /// these share the pattern that if the id is local, it should have been loaded
1800 /// into the map by the `typeck::collect` phase. If the def-id is external,
1801 /// then we have to go consult the crate loading code (and cache the result for
1802 /// the future).
1803 fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
1804 def_id: DefId,
1805 map: &M,
1806 load_external: F)
1807 -> M::Value where
1808 M: MemoizationMap<Key=DefId>,
1809 F: FnOnce() -> M::Value,
1810 {
1811 map.memoize(def_id, || {
1812 if def_id.is_local() {
1813 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
1814 }
1815 load_external()
1816 })
1817 }
1818
1819 impl BorrowKind {
1820 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
1821 match m {
1822 hir::MutMutable => MutBorrow,
1823 hir::MutImmutable => ImmBorrow,
1824 }
1825 }
1826
1827 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
1828 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
1829 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
1830 /// question.
1831 pub fn to_mutbl_lossy(self) -> hir::Mutability {
1832 match self {
1833 MutBorrow => hir::MutMutable,
1834 ImmBorrow => hir::MutImmutable,
1835
1836 // We have no type corresponding to a unique imm borrow, so
1837 // use `&mut`. It gives all the capabilities of an `&uniq`
1838 // and hence is a safe "over approximation".
1839 UniqueImmBorrow => hir::MutMutable,
1840 }
1841 }
1842
1843 pub fn to_user_str(&self) -> &'static str {
1844 match *self {
1845 MutBorrow => "mutable",
1846 ImmBorrow => "immutable",
1847 UniqueImmBorrow => "uniquely immutable",
1848 }
1849 }
1850 }
1851
1852 impl<'tcx> ctxt<'tcx> {
1853 pub fn node_id_to_type(&self, id: NodeId) -> Ty<'tcx> {
1854 match self.node_id_to_type_opt(id) {
1855 Some(ty) => ty,
1856 None => self.sess.bug(
1857 &format!("node_id_to_type: no type for node `{}`",
1858 self.map.node_to_string(id)))
1859 }
1860 }
1861
1862 pub fn node_id_to_type_opt(&self, id: NodeId) -> Option<Ty<'tcx>> {
1863 self.tables.borrow().node_types.get(&id).cloned()
1864 }
1865
1866 pub fn node_id_item_substs(&self, id: NodeId) -> ItemSubsts<'tcx> {
1867 match self.tables.borrow().item_substs.get(&id) {
1868 None => ItemSubsts::empty(),
1869 Some(ts) => ts.clone(),
1870 }
1871 }
1872
1873 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
1874 // doesn't provide type parameter substitutions.
1875 pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
1876 self.node_id_to_type(pat.id)
1877 }
1878 pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
1879 self.node_id_to_type_opt(pat.id)
1880 }
1881
1882 // Returns the type of an expression as a monotype.
1883 //
1884 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
1885 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
1886 // auto-ref. The type returned by this function does not consider such
1887 // adjustments. See `expr_ty_adjusted()` instead.
1888 //
1889 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
1890 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
1891 // instead of "fn(ty) -> T with T = isize".
1892 pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
1893 self.node_id_to_type(expr.id)
1894 }
1895
1896 pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1897 self.node_id_to_type_opt(expr.id)
1898 }
1899
1900 /// Returns the type of `expr`, considering any `AutoAdjustment`
1901 /// entry recorded for that expression.
1902 ///
1903 /// It would almost certainly be better to store the adjusted ty in with
1904 /// the `AutoAdjustment`, but I opted not to do this because it would
1905 /// require serializing and deserializing the type and, although that's not
1906 /// hard to do, I just hate that code so much I didn't want to touch it
1907 /// unless it was to fix it properly, which seemed a distraction from the
1908 /// thread at hand! -nmatsakis
1909 pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
1910 self.expr_ty(expr)
1911 .adjust(self, expr.span, expr.id,
1912 self.tables.borrow().adjustments.get(&expr.id),
1913 |method_call| {
1914 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
1915 })
1916 }
1917
1918 pub fn expr_ty_adjusted_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
1919 self.expr_ty_opt(expr).map(|t| t.adjust(self,
1920 expr.span,
1921 expr.id,
1922 self.tables.borrow().adjustments.get(&expr.id),
1923 |method_call| {
1924 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
1925 }))
1926 }
1927
1928 pub fn expr_span(&self, id: NodeId) -> Span {
1929 match self.map.find(id) {
1930 Some(ast_map::NodeExpr(e)) => {
1931 e.span
1932 }
1933 Some(f) => {
1934 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
1935 id, f));
1936 }
1937 None => {
1938 self.sess.bug(&format!("Node id {} is not present \
1939 in the node map", id));
1940 }
1941 }
1942 }
1943
1944 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
1945 match self.map.find(id) {
1946 Some(ast_map::NodeLocal(pat)) => {
1947 match pat.node {
1948 PatKind::Ident(_, ref path1, _) => path1.node.name.as_str(),
1949 _ => {
1950 self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, pat));
1951 },
1952 }
1953 },
1954 r => self.sess.bug(&format!("Variable id {} maps to {:?}, not local", id, r)),
1955 }
1956 }
1957
1958 pub fn resolve_expr(&self, expr: &hir::Expr) -> Def {
1959 match self.def_map.borrow().get(&expr.id) {
1960 Some(def) => def.full_def(),
1961 None => {
1962 self.sess.span_bug(expr.span, &format!(
1963 "no def-map entry for expr {}", expr.id));
1964 }
1965 }
1966 }
1967
1968 pub fn expr_is_lval(&self, expr: &hir::Expr) -> bool {
1969 match expr.node {
1970 hir::ExprPath(..) => {
1971 // We can't use resolve_expr here, as this needs to run on broken
1972 // programs. We don't need to through - associated items are all
1973 // rvalues.
1974 match self.def_map.borrow().get(&expr.id) {
1975 Some(&def::PathResolution {
1976 base_def: Def::Static(..), ..
1977 }) | Some(&def::PathResolution {
1978 base_def: Def::Upvar(..), ..
1979 }) | Some(&def::PathResolution {
1980 base_def: Def::Local(..), ..
1981 }) => {
1982 true
1983 }
1984 Some(&def::PathResolution { base_def: Def::Err, .. })=> true,
1985 Some(..) => false,
1986 None => self.sess.span_bug(expr.span, &format!(
1987 "no def for path {}", expr.id))
1988 }
1989 }
1990
1991 hir::ExprType(ref e, _) => {
1992 self.expr_is_lval(e)
1993 }
1994
1995 hir::ExprUnary(hir::UnDeref, _) |
1996 hir::ExprField(..) |
1997 hir::ExprTupField(..) |
1998 hir::ExprIndex(..) => {
1999 true
2000 }
2001
2002 hir::ExprCall(..) |
2003 hir::ExprMethodCall(..) |
2004 hir::ExprStruct(..) |
2005 hir::ExprRange(..) |
2006 hir::ExprTup(..) |
2007 hir::ExprIf(..) |
2008 hir::ExprMatch(..) |
2009 hir::ExprClosure(..) |
2010 hir::ExprBlock(..) |
2011 hir::ExprRepeat(..) |
2012 hir::ExprVec(..) |
2013 hir::ExprBreak(..) |
2014 hir::ExprAgain(..) |
2015 hir::ExprRet(..) |
2016 hir::ExprWhile(..) |
2017 hir::ExprLoop(..) |
2018 hir::ExprAssign(..) |
2019 hir::ExprInlineAsm(..) |
2020 hir::ExprAssignOp(..) |
2021 hir::ExprLit(_) |
2022 hir::ExprUnary(..) |
2023 hir::ExprBox(..) |
2024 hir::ExprAddrOf(..) |
2025 hir::ExprBinary(..) |
2026 hir::ExprCast(..) => {
2027 false
2028 }
2029 }
2030 }
2031
2032 pub fn provided_trait_methods(&self, id: DefId) -> Vec<Rc<Method<'tcx>>> {
2033 if let Some(id) = self.map.as_local_node_id(id) {
2034 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id).node {
2035 ms.iter().filter_map(|ti| {
2036 if let hir::MethodTraitItem(_, Some(_)) = ti.node {
2037 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2038 MethodTraitItem(m) => Some(m),
2039 _ => {
2040 self.sess.bug("provided_trait_methods(): \
2041 non-method item found from \
2042 looking up provided method?!")
2043 }
2044 }
2045 } else {
2046 None
2047 }
2048 }).collect()
2049 } else {
2050 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
2051 }
2052 } else {
2053 self.sess.cstore.provided_trait_methods(self, id)
2054 }
2055 }
2056
2057 pub fn associated_consts(&self, id: DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
2058 if let Some(id) = self.map.as_local_node_id(id) {
2059 match self.map.expect_item(id).node {
2060 ItemTrait(_, _, _, ref tis) => {
2061 tis.iter().filter_map(|ti| {
2062 if let hir::ConstTraitItem(_, _) = ti.node {
2063 match self.impl_or_trait_item(self.map.local_def_id(ti.id)) {
2064 ConstTraitItem(ac) => Some(ac),
2065 _ => {
2066 self.sess.bug("associated_consts(): \
2067 non-const item found from \
2068 looking up a constant?!")
2069 }
2070 }
2071 } else {
2072 None
2073 }
2074 }).collect()
2075 }
2076 ItemImpl(_, _, _, _, _, ref iis) => {
2077 iis.iter().filter_map(|ii| {
2078 if let hir::ImplItemKind::Const(_, _) = ii.node {
2079 match self.impl_or_trait_item(self.map.local_def_id(ii.id)) {
2080 ConstTraitItem(ac) => Some(ac),
2081 _ => {
2082 self.sess.bug("associated_consts(): \
2083 non-const item found from \
2084 looking up a constant?!")
2085 }
2086 }
2087 } else {
2088 None
2089 }
2090 }).collect()
2091 }
2092 _ => {
2093 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
2094 or impl", id))
2095 }
2096 }
2097 } else {
2098 self.sess.cstore.associated_consts(self, id)
2099 }
2100 }
2101
2102 pub fn trait_impl_polarity(&self, id: DefId) -> Option<hir::ImplPolarity> {
2103 if let Some(id) = self.map.as_local_node_id(id) {
2104 match self.map.find(id) {
2105 Some(ast_map::NodeItem(item)) => {
2106 match item.node {
2107 hir::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
2108 _ => None
2109 }
2110 }
2111 _ => None
2112 }
2113 } else {
2114 self.sess.cstore.impl_polarity(id)
2115 }
2116 }
2117
2118 pub fn custom_coerce_unsized_kind(&self, did: DefId) -> adjustment::CustomCoerceUnsized {
2119 self.custom_coerce_unsized_kinds.memoize(did, || {
2120 let (kind, src) = if did.krate != LOCAL_CRATE {
2121 (self.sess.cstore.custom_coerce_unsized_kind(did), "external")
2122 } else {
2123 (None, "local")
2124 };
2125
2126 match kind {
2127 Some(kind) => kind,
2128 None => {
2129 self.sess.bug(&format!("custom_coerce_unsized_kind: \
2130 {} impl `{}` is missing its kind",
2131 src, self.item_path_str(did)));
2132 }
2133 }
2134 })
2135 }
2136
2137 pub fn impl_or_trait_item(&self, id: DefId) -> ImplOrTraitItem<'tcx> {
2138 lookup_locally_or_in_crate_store(
2139 "impl_or_trait_items", id, &self.impl_or_trait_items,
2140 || self.sess.cstore.impl_or_trait_item(self, id))
2141 }
2142
2143 pub fn trait_item_def_ids(&self, id: DefId) -> Rc<Vec<ImplOrTraitItemId>> {
2144 lookup_locally_or_in_crate_store(
2145 "trait_item_def_ids", id, &self.trait_item_def_ids,
2146 || Rc::new(self.sess.cstore.trait_item_def_ids(id)))
2147 }
2148
2149 /// Returns the trait-ref corresponding to a given impl, or None if it is
2150 /// an inherent impl.
2151 pub fn impl_trait_ref(&self, id: DefId) -> Option<TraitRef<'tcx>> {
2152 lookup_locally_or_in_crate_store(
2153 "impl_trait_refs", id, &self.impl_trait_refs,
2154 || self.sess.cstore.impl_trait_ref(self, id))
2155 }
2156
2157 /// Returns whether this DefId refers to an impl
2158 pub fn is_impl(&self, id: DefId) -> bool {
2159 if let Some(id) = self.map.as_local_node_id(id) {
2160 if let Some(ast_map::NodeItem(
2161 &hir::Item { node: hir::ItemImpl(..), .. })) = self.map.find(id) {
2162 true
2163 } else {
2164 false
2165 }
2166 } else {
2167 self.sess.cstore.is_impl(id)
2168 }
2169 }
2170
2171 pub fn trait_ref_to_def_id(&self, tr: &hir::TraitRef) -> DefId {
2172 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
2173 }
2174
2175 pub fn item_path_str(&self, id: DefId) -> String {
2176 self.with_path(id, |path| ast_map::path_to_string(path))
2177 }
2178
2179 pub fn def_path(&self, id: DefId) -> ast_map::DefPath {
2180 if id.is_local() {
2181 self.map.def_path(id)
2182 } else {
2183 self.sess.cstore.def_path(id)
2184 }
2185 }
2186
2187 pub fn with_path<T, F>(&self, id: DefId, f: F) -> T where
2188 F: FnOnce(ast_map::PathElems) -> T,
2189 {
2190 if let Some(id) = self.map.as_local_node_id(id) {
2191 self.map.with_path(id, f)
2192 } else {
2193 f(self.sess.cstore.item_path(id).iter().cloned().chain(LinkedPath::empty()))
2194 }
2195 }
2196
2197 pub fn item_name(&self, id: DefId) -> ast::Name {
2198 if let Some(id) = self.map.as_local_node_id(id) {
2199 self.map.get_path_elem(id).name()
2200 } else {
2201 self.sess.cstore.item_name(id)
2202 }
2203 }
2204
2205 // Register a given item type
2206 pub fn register_item_type(&self, did: DefId, ty: TypeScheme<'tcx>) {
2207 self.tcache.borrow_mut().insert(did, ty);
2208 }
2209
2210 // If the given item is in an external crate, looks up its type and adds it to
2211 // the type cache. Returns the type parameters and type.
2212 pub fn lookup_item_type(&self, did: DefId) -> TypeScheme<'tcx> {
2213 lookup_locally_or_in_crate_store(
2214 "tcache", did, &self.tcache,
2215 || self.sess.cstore.item_type(self, did))
2216 }
2217
2218 /// Given the did of a trait, returns its canonical trait ref.
2219 pub fn lookup_trait_def(&self, did: DefId) -> &'tcx TraitDef<'tcx> {
2220 lookup_locally_or_in_crate_store(
2221 "trait_defs", did, &self.trait_defs,
2222 || self.alloc_trait_def(self.sess.cstore.trait_def(self, did))
2223 )
2224 }
2225
2226 /// Given the did of an ADT, return a master reference to its
2227 /// definition. Unless you are planning on fulfilling the ADT's fields,
2228 /// use lookup_adt_def instead.
2229 pub fn lookup_adt_def_master(&self, did: DefId) -> AdtDefMaster<'tcx> {
2230 lookup_locally_or_in_crate_store(
2231 "adt_defs", did, &self.adt_defs,
2232 || self.sess.cstore.adt_def(self, did)
2233 )
2234 }
2235
2236 /// Given the did of an ADT, return a reference to its definition.
2237 pub fn lookup_adt_def(&self, did: DefId) -> AdtDef<'tcx> {
2238 // when reverse-variance goes away, a transmute::<AdtDefMaster,AdtDef>
2239 // would be needed here.
2240 self.lookup_adt_def_master(did)
2241 }
2242
2243 /// Given the did of an item, returns its full set of predicates.
2244 pub fn lookup_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2245 lookup_locally_or_in_crate_store(
2246 "predicates", did, &self.predicates,
2247 || self.sess.cstore.item_predicates(self, did))
2248 }
2249
2250 /// Given the did of a trait, returns its superpredicates.
2251 pub fn lookup_super_predicates(&self, did: DefId) -> GenericPredicates<'tcx> {
2252 lookup_locally_or_in_crate_store(
2253 "super_predicates", did, &self.super_predicates,
2254 || self.sess.cstore.item_super_predicates(self, did))
2255 }
2256
2257 /// If `type_needs_drop` returns true, then `ty` is definitely
2258 /// non-copy and *might* have a destructor attached; if it returns
2259 /// false, then `ty` definitely has no destructor (i.e. no drop glue).
2260 ///
2261 /// (Note that this implies that if `ty` has a destructor attached,
2262 /// then `type_needs_drop` will definitely return `true` for `ty`.)
2263 pub fn type_needs_drop_given_env<'a>(&self,
2264 ty: Ty<'tcx>,
2265 param_env: &ty::ParameterEnvironment<'a,'tcx>) -> bool {
2266 // Issue #22536: We first query type_moves_by_default. It sees a
2267 // normalized version of the type, and therefore will definitely
2268 // know whether the type implements Copy (and thus needs no
2269 // cleanup/drop/zeroing) ...
2270 let implements_copy = !ty.moves_by_default(param_env, DUMMY_SP);
2271
2272 if implements_copy { return false; }
2273
2274 // ... (issue #22536 continued) but as an optimization, still use
2275 // prior logic of asking if the `needs_drop` bit is set; we need
2276 // not zero non-Copy types if they have no destructor.
2277
2278 // FIXME(#22815): Note that calling `ty::type_contents` is a
2279 // conservative heuristic; it may report that `needs_drop` is set
2280 // when actual type does not actually have a destructor associated
2281 // with it. But since `ty` absolutely did not have the `Copy`
2282 // bound attached (see above), it is sound to treat it as having a
2283 // destructor (e.g. zero its memory on move).
2284
2285 let contents = ty.type_contents(self);
2286 debug!("type_needs_drop ty={:?} contents={:?}", ty, contents);
2287 contents.needs_drop(self)
2288 }
2289
2290 /// Get the attributes of a definition.
2291 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [ast::Attribute]> {
2292 if let Some(id) = self.map.as_local_node_id(did) {
2293 Cow::Borrowed(self.map.attrs(id))
2294 } else {
2295 Cow::Owned(self.sess.cstore.item_attrs(did))
2296 }
2297 }
2298
2299 /// Determine whether an item is annotated with an attribute
2300 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
2301 self.get_attrs(did).iter().any(|item| item.check_name(attr))
2302 }
2303
2304 /// Determine whether an item is annotated with `#[repr(packed)]`
2305 pub fn lookup_packed(&self, did: DefId) -> bool {
2306 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
2307 }
2308
2309 /// Determine whether an item is annotated with `#[simd]`
2310 pub fn lookup_simd(&self, did: DefId) -> bool {
2311 self.has_attr(did, "simd")
2312 || self.lookup_repr_hints(did).contains(&attr::ReprSimd)
2313 }
2314
2315 pub fn item_variances(&self, item_id: DefId) -> Rc<ItemVariances> {
2316 lookup_locally_or_in_crate_store(
2317 "item_variance_map", item_id, &self.item_variance_map,
2318 || Rc::new(self.sess.cstore.item_variances(item_id)))
2319 }
2320
2321 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
2322 self.populate_implementations_for_trait_if_necessary(trait_def_id);
2323
2324 let def = self.lookup_trait_def(trait_def_id);
2325 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
2326 }
2327
2328 /// Records a trait-to-implementation mapping.
2329 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
2330 let def = self.lookup_trait_def(trait_def_id);
2331 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
2332 }
2333
2334 /// Load primitive inherent implementations if necessary
2335 pub fn populate_implementations_for_primitive_if_necessary(&self,
2336 primitive_def_id: DefId) {
2337 if primitive_def_id.is_local() {
2338 return
2339 }
2340
2341 // The primitive is not local, hence we are reading this out
2342 // of metadata.
2343 let _ignore = self.dep_graph.in_ignore();
2344
2345 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
2346 return
2347 }
2348
2349 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
2350 primitive_def_id);
2351
2352 let impl_items = self.sess.cstore.impl_items(primitive_def_id);
2353
2354 // Store the implementation info.
2355 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
2356 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
2357 }
2358
2359 /// Populates the type context with all the inherent implementations for
2360 /// the given type if necessary.
2361 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
2362 type_id: DefId) {
2363 if type_id.is_local() {
2364 return
2365 }
2366
2367 // The type is not local, hence we are reading this out of
2368 // metadata and don't need to track edges.
2369 let _ignore = self.dep_graph.in_ignore();
2370
2371 if self.populated_external_types.borrow().contains(&type_id) {
2372 return
2373 }
2374
2375 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
2376 type_id);
2377
2378 let inherent_impls = self.sess.cstore.inherent_implementations_for_type(type_id);
2379 for &impl_def_id in &inherent_impls {
2380 // Store the implementation info.
2381 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2382 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2383 }
2384
2385 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
2386 self.populated_external_types.borrow_mut().insert(type_id);
2387 }
2388
2389 /// Populates the type context with all the implementations for the given
2390 /// trait if necessary.
2391 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: DefId) {
2392 if trait_id.is_local() {
2393 return
2394 }
2395
2396 // The type is not local, hence we are reading this out of
2397 // metadata and don't need to track edges.
2398 let _ignore = self.dep_graph.in_ignore();
2399
2400 let def = self.lookup_trait_def(trait_id);
2401 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
2402 return;
2403 }
2404
2405 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
2406
2407 if self.sess.cstore.is_defaulted_trait(trait_id) {
2408 self.record_trait_has_default_impl(trait_id);
2409 }
2410
2411 for impl_def_id in self.sess.cstore.implementations_of_trait(trait_id) {
2412 let impl_items = self.sess.cstore.impl_items(impl_def_id);
2413 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
2414 // Record the trait->implementation mapping.
2415 def.record_impl(self, impl_def_id, trait_ref);
2416
2417 // For any methods that use a default implementation, add them to
2418 // the map. This is a bit unfortunate.
2419 for impl_item_def_id in &impl_items {
2420 let method_def_id = impl_item_def_id.def_id();
2421 // load impl items eagerly for convenience
2422 // FIXME: we may want to load these lazily
2423 self.impl_or_trait_item(method_def_id);
2424 }
2425
2426 // Store the implementation info.
2427 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
2428 }
2429
2430 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
2431 }
2432
2433 pub fn closure_kind(&self, def_id: DefId) -> ty::ClosureKind {
2434 Tables::closure_kind(&self.tables, self, def_id)
2435 }
2436
2437 pub fn closure_type(&self,
2438 def_id: DefId,
2439 substs: &ClosureSubsts<'tcx>)
2440 -> ty::ClosureTy<'tcx>
2441 {
2442 Tables::closure_type(&self.tables, self, def_id, substs)
2443 }
2444
2445 /// Given the def_id of an impl, return the def_id of the trait it implements.
2446 /// If it implements no trait, return `None`.
2447 pub fn trait_id_of_impl(&self, def_id: DefId) -> Option<DefId> {
2448 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2449 }
2450
2451 /// If the given def ID describes a method belonging to an impl, return the
2452 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2453 pub fn impl_of_method(&self, def_id: DefId) -> Option<DefId> {
2454 if def_id.krate != LOCAL_CRATE {
2455 return match self.sess.cstore.impl_or_trait_item(self, def_id).container() {
2456 TraitContainer(_) => None,
2457 ImplContainer(def_id) => Some(def_id),
2458 };
2459 }
2460 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2461 Some(trait_item) => {
2462 match trait_item.container() {
2463 TraitContainer(_) => None,
2464 ImplContainer(def_id) => Some(def_id),
2465 }
2466 }
2467 None => None
2468 }
2469 }
2470
2471 /// If the given def ID describes an item belonging to a trait (either a
2472 /// default method or an implementation of a trait method), return the ID of
2473 /// the trait that the method belongs to. Otherwise, return `None`.
2474 pub fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
2475 if def_id.krate != LOCAL_CRATE {
2476 return self.sess.cstore.trait_of_item(self, def_id);
2477 }
2478 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
2479 Some(impl_or_trait_item) => {
2480 match impl_or_trait_item.container() {
2481 TraitContainer(def_id) => Some(def_id),
2482 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
2483 }
2484 }
2485 None => None
2486 }
2487 }
2488
2489 /// If the given def ID describes an item belonging to a trait, (either a
2490 /// default method or an implementation of a trait method), return the ID of
2491 /// the method inside trait definition (this means that if the given def ID
2492 /// is already that of the original trait method, then the return value is
2493 /// the same).
2494 /// Otherwise, return `None`.
2495 pub fn trait_item_of_item(&self, def_id: DefId) -> Option<ImplOrTraitItemId> {
2496 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
2497 Some(m) => m.clone(),
2498 None => return None,
2499 };
2500 let name = impl_item.name();
2501 match self.trait_of_item(def_id) {
2502 Some(trait_did) => {
2503 self.trait_items(trait_did).iter()
2504 .find(|item| item.name() == name)
2505 .map(|item| item.id())
2506 }
2507 None => None
2508 }
2509 }
2510
2511 /// Construct a parameter environment suitable for static contexts or other contexts where there
2512 /// are no free type/lifetime parameters in scope.
2513 pub fn empty_parameter_environment<'a>(&'a self)
2514 -> ParameterEnvironment<'a,'tcx> {
2515
2516 // for an empty parameter environment, there ARE no free
2517 // regions, so it shouldn't matter what we use for the free id
2518 let free_id_outlive = self.region_maps.node_extent(ast::DUMMY_NODE_ID);
2519 ty::ParameterEnvironment { tcx: self,
2520 free_substs: Substs::empty(),
2521 caller_bounds: Vec::new(),
2522 implicit_region_bound: ty::ReEmpty,
2523 selection_cache: traits::SelectionCache::new(),
2524 evaluation_cache: traits::EvaluationCache::new(),
2525 free_id_outlive: free_id_outlive }
2526 }
2527
2528 /// Constructs and returns a substitution that can be applied to move from
2529 /// the "outer" view of a type or method to the "inner" view.
2530 /// In general, this means converting from bound parameters to
2531 /// free parameters. Since we currently represent bound/free type
2532 /// parameters in the same way, this only has an effect on regions.
2533 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
2534 free_id_outlive: CodeExtent) -> Substs<'tcx> {
2535 // map T => T
2536 let mut types = VecPerParamSpace::empty();
2537 for def in generics.types.as_slice() {
2538 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
2539 def);
2540 types.push(def.space, self.mk_param_from_def(def));
2541 }
2542
2543 // map bound 'a => free 'a
2544 let mut regions = VecPerParamSpace::empty();
2545 for def in generics.regions.as_slice() {
2546 let region =
2547 ReFree(FreeRegion { scope: free_id_outlive,
2548 bound_region: BrNamed(def.def_id, def.name) });
2549 debug!("push_region_params {:?}", region);
2550 regions.push(def.space, region);
2551 }
2552
2553 Substs {
2554 types: types,
2555 regions: subst::NonerasedRegions(regions)
2556 }
2557 }
2558
2559 /// See `ParameterEnvironment` struct def'n for details.
2560 /// If you were using `free_id: NodeId`, you might try `self.region_maps.item_extent(free_id)`
2561 /// for the `free_id_outlive` parameter. (But note that that is not always quite right.)
2562 pub fn construct_parameter_environment<'a>(&'a self,
2563 span: Span,
2564 generics: &ty::Generics<'tcx>,
2565 generic_predicates: &ty::GenericPredicates<'tcx>,
2566 free_id_outlive: CodeExtent)
2567 -> ParameterEnvironment<'a, 'tcx>
2568 {
2569 //
2570 // Construct the free substs.
2571 //
2572
2573 let free_substs = self.construct_free_substs(generics, free_id_outlive);
2574
2575 //
2576 // Compute the bounds on Self and the type parameters.
2577 //
2578
2579 let bounds = generic_predicates.instantiate(self, &free_substs);
2580 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
2581 let predicates = bounds.predicates.into_vec();
2582
2583 // Finally, we have to normalize the bounds in the environment, in
2584 // case they contain any associated type projections. This process
2585 // can yield errors if the put in illegal associated types, like
2586 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2587 // report these errors right here; this doesn't actually feel
2588 // right to me, because constructing the environment feels like a
2589 // kind of a "idempotent" action, but I'm not sure where would be
2590 // a better place. In practice, we construct environments for
2591 // every fn once during type checking, and we'll abort if there
2592 // are any errors at that point, so after type checking you can be
2593 // sure that this will succeed without errors anyway.
2594 //
2595
2596 let unnormalized_env = ty::ParameterEnvironment {
2597 tcx: self,
2598 free_substs: free_substs,
2599 implicit_region_bound: ty::ReScope(free_id_outlive),
2600 caller_bounds: predicates,
2601 selection_cache: traits::SelectionCache::new(),
2602 evaluation_cache: traits::EvaluationCache::new(),
2603 free_id_outlive: free_id_outlive,
2604 };
2605
2606 let cause = traits::ObligationCause::misc(span, free_id_outlive.node_id(&self.region_maps));
2607 traits::normalize_param_env_or_error(unnormalized_env, cause)
2608 }
2609
2610 pub fn is_method_call(&self, expr_id: NodeId) -> bool {
2611 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
2612 }
2613
2614 pub fn is_overloaded_autoderef(&self, expr_id: NodeId, autoderefs: u32) -> bool {
2615 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
2616 autoderefs))
2617 }
2618
2619 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
2620 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
2621 }
2622
2623
2624 pub fn visit_all_items_in_krate<V,F>(&self,
2625 dep_node_fn: F,
2626 visitor: &mut V)
2627 where F: FnMut(DefId) -> DepNode, V: Visitor<'tcx>
2628 {
2629 dep_graph::visit_all_items_in_krate(self, dep_node_fn, visitor);
2630 }
2631 }
2632
2633 /// The category of explicit self.
2634 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
2635 pub enum ExplicitSelfCategory {
2636 Static,
2637 ByValue,
2638 ByReference(Region, hir::Mutability),
2639 ByBox,
2640 }
2641
2642 /// A free variable referred to in a function.
2643 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
2644 pub struct Freevar {
2645 /// The variable being accessed free.
2646 pub def: Def,
2647
2648 // First span where it is accessed (there can be multiple).
2649 pub span: Span
2650 }
2651
2652 pub type FreevarMap = NodeMap<Vec<Freevar>>;
2653
2654 pub type CaptureModeMap = NodeMap<hir::CaptureClause>;
2655
2656 // Trait method resolution
2657 pub type TraitMap = NodeMap<Vec<DefId>>;
2658
2659 // Map from the NodeId of a glob import to a list of items which are actually
2660 // imported.
2661 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
2662
2663 impl<'tcx> ctxt<'tcx> {
2664 pub fn with_freevars<T, F>(&self, fid: NodeId, f: F) -> T where
2665 F: FnOnce(&[Freevar]) -> T,
2666 {
2667 match self.freevars.borrow().get(&fid) {
2668 None => f(&[]),
2669 Some(d) => f(&d[..])
2670 }
2671 }
2672
2673 pub fn make_substs_for_receiver_types(&self,
2674 trait_ref: &ty::TraitRef<'tcx>,
2675 method: &ty::Method<'tcx>)
2676 -> subst::Substs<'tcx>
2677 {
2678 /*!
2679 * Substitutes the values for the receiver's type parameters
2680 * that are found in method, leaving the method's type parameters
2681 * intact.
2682 */
2683
2684 let meth_tps: Vec<Ty> =
2685 method.generics.types.get_slice(subst::FnSpace)
2686 .iter()
2687 .map(|def| self.mk_param_from_def(def))
2688 .collect();
2689 let meth_regions: Vec<ty::Region> =
2690 method.generics.regions.get_slice(subst::FnSpace)
2691 .iter()
2692 .map(|def| def.to_early_bound_region())
2693 .collect();
2694 trait_ref.substs.clone().with_method(meth_tps, meth_regions)
2695 }
2696 }