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 // FIXME: (@jroesch) @eddyb should remove this when he renames ctxt
12 #![allow(non_camel_case_types)]
14 pub use self::InferTy::*;
15 pub use self::InferRegion::*;
16 pub use self::ImplOrTraitItemId::*;
17 pub use self::ClosureKind::*;
18 pub use self::Variance::*;
19 pub use self::AutoAdjustment::*;
20 pub use self::Representability::*;
21 pub use self::AutoRef::*;
22 pub use self::DtorKind::*;
23 pub use self::ExplicitSelfCategory::*;
24 pub use self::FnOutput::*;
25 pub use self::Region::*;
26 pub use self::ImplOrTraitItemContainer::*;
27 pub use self::BorrowKind::*;
28 pub use self::ImplOrTraitItem::*;
29 pub use self::BoundRegion::*;
30 pub use self::TypeVariants::*;
31 pub use self::IntVarValue::*;
32 pub use self::CopyImplementationError::*;
34 pub use self::BuiltinBound::Send as BoundSend;
35 pub use self::BuiltinBound::Sized as BoundSized;
36 pub use self::BuiltinBound::Copy as BoundCopy;
37 pub use self::BuiltinBound::Sync as BoundSync;
39 use ast_map::{self, LinkedPath};
43 use metadata::csearch;
46 use middle::check_const;
47 use middle::const_eval::{self, ConstVal};
48 use middle::const_eval::EvalHint::UncheckedExprHint;
49 use middle::def::{self, DefMap, ExportMap};
50 use middle::dependency_format;
51 use middle::fast_reject;
52 use middle::free_region::FreeRegionMap;
53 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
55 use middle::resolve_lifetime;
57 use middle::infer::type_variable;
59 use middle::region::RegionMaps;
60 use middle::stability;
61 use middle::subst::{self, ParamSpace, Subst, Substs, VecPerParamSpace};
64 use middle::ty_fold::{self, TypeFoldable, TypeFolder};
65 use middle::ty_walk::{self, TypeWalker};
66 use util::common::{memoized, ErrorReported};
67 use util::nodemap::{NodeMap, NodeSet, DefIdMap, DefIdSet};
68 use util::nodemap::FnvHashMap;
69 use util::num::ToPrimitive;
71 use arena::TypedArena;
72 use std::borrow::{Borrow, Cow};
73 use std::cell::{Cell, RefCell, Ref};
76 use std::hash::{Hash, SipHasher, Hasher};
80 use std::vec::IntoIter;
81 use collections::enum_set::{self, EnumSet, CLike};
82 use std::collections::{HashMap, HashSet};
84 use syntax::ast::{CrateNum, DefId, ItemImpl, ItemTrait, LOCAL_CRATE};
85 use syntax::ast::{MutImmutable, MutMutable, Name, NamedField, NodeId};
86 use syntax::ast::{StructField, UnnamedField, Visibility};
87 use syntax::ast_util::{self, is_local, local_def};
88 use syntax::attr::{self, AttrMetaMethods, SignedInt, UnsignedInt};
89 use syntax::codemap::Span;
90 use syntax::parse::token::{self, InternedString, special_idents};
91 use syntax::print::pprust;
97 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
101 /// The complete set of all analyses described in this module. This is
102 /// produced by the driver and fed to trans and later passes.
103 pub struct CrateAnalysis {
104 pub export_map: ExportMap,
105 pub exported_items: middle::privacy::ExportedItems,
106 pub public_items: middle::privacy::PublicItems,
107 pub reachable: NodeSet,
109 pub glob_map: Option<GlobMap>,
112 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
113 pub struct Field<'tcx> {
115 pub mt: TypeAndMut<'tcx>
122 pub struct VariantInfo<'tcx> {
123 pub args: Vec<Ty<'tcx>>,
124 pub arg_names: Option<Vec<ast::Name>>,
125 pub ctor_ty: Option<Ty<'tcx>>,
132 impl<'tcx> VariantInfo<'tcx> {
134 /// Creates a new VariantInfo from the corresponding ast representation.
136 /// Does not do any caching of the value in the type context.
137 pub fn from_ast_variant(cx: &ctxt<'tcx>,
138 ast_variant: &ast::Variant,
139 discriminant: Disr) -> VariantInfo<'tcx> {
140 let ctor_ty = cx.node_id_to_type(ast_variant.node.id);
142 match ast_variant.node.kind {
143 ast::TupleVariantKind(ref args) => {
144 let arg_tys = if !args.is_empty() {
145 // the regions in the argument types come from the
146 // enum def'n, and hence will all be early bound
147 cx.no_late_bound_regions(&ctor_ty.fn_args()).unwrap()
155 ctor_ty: Some(ctor_ty),
156 name: ast_variant.node.name.name,
157 id: ast_util::local_def(ast_variant.node.id),
158 disr_val: discriminant,
159 vis: ast_variant.node.vis
162 ast::StructVariantKind(ref struct_def) => {
163 let fields: &[StructField] = &struct_def.fields;
165 assert!(!fields.is_empty());
167 let arg_tys = struct_def.fields.iter()
168 .map(|field| cx.node_id_to_type(field.node.id)).collect();
169 let arg_names = fields.iter().map(|field| {
170 match field.node.kind {
171 NamedField(ident, _) => ident.name,
172 UnnamedField(..) => cx.sess.bug(
173 "enum_variants: all fields in struct must have a name")
179 arg_names: Some(arg_names),
181 name: ast_variant.node.name.name,
182 id: ast_util::local_def(ast_variant.node.id),
183 disr_val: discriminant,
184 vis: ast_variant.node.vis
191 #[derive(Copy, Clone)]
194 TraitDtor(DefId, bool)
198 pub fn is_present(&self) -> bool {
200 TraitDtor(..) => true,
205 pub fn has_drop_flag(&self) -> bool {
208 &TraitDtor(_, flag) => flag
214 fn to_ty<'tcx>(&self, cx: &ctxt<'tcx>) -> Ty<'tcx>;
215 fn i64_to_disr(&self, val: i64) -> Option<Disr>;
216 fn u64_to_disr(&self, val: u64) -> Option<Disr>;
217 fn disr_incr(&self, val: Disr) -> Option<Disr>;
218 fn disr_string(&self, val: Disr) -> String;
219 fn disr_wrap_incr(&self, val: Option<Disr>) -> Disr;
222 impl IntTypeExt for attr::IntType {
223 fn to_ty<'tcx>(&self, cx: &ctxt<'tcx>) -> Ty<'tcx> {
225 SignedInt(ast::TyI8) => cx.types.i8,
226 SignedInt(ast::TyI16) => cx.types.i16,
227 SignedInt(ast::TyI32) => cx.types.i32,
228 SignedInt(ast::TyI64) => cx.types.i64,
229 SignedInt(ast::TyIs) => cx.types.isize,
230 UnsignedInt(ast::TyU8) => cx.types.u8,
231 UnsignedInt(ast::TyU16) => cx.types.u16,
232 UnsignedInt(ast::TyU32) => cx.types.u32,
233 UnsignedInt(ast::TyU64) => cx.types.u64,
234 UnsignedInt(ast::TyUs) => cx.types.usize,
238 fn i64_to_disr(&self, val: i64) -> Option<Disr> {
240 SignedInt(ast::TyI8) => val.to_i8() .map(|v| v as Disr),
241 SignedInt(ast::TyI16) => val.to_i16() .map(|v| v as Disr),
242 SignedInt(ast::TyI32) => val.to_i32() .map(|v| v as Disr),
243 SignedInt(ast::TyI64) => val.to_i64() .map(|v| v as Disr),
244 UnsignedInt(ast::TyU8) => val.to_u8() .map(|v| v as Disr),
245 UnsignedInt(ast::TyU16) => val.to_u16() .map(|v| v as Disr),
246 UnsignedInt(ast::TyU32) => val.to_u32() .map(|v| v as Disr),
247 UnsignedInt(ast::TyU64) => val.to_u64() .map(|v| v as Disr),
249 UnsignedInt(ast::TyUs) |
250 SignedInt(ast::TyIs) => unreachable!(),
254 fn u64_to_disr(&self, val: u64) -> Option<Disr> {
256 SignedInt(ast::TyI8) => val.to_i8() .map(|v| v as Disr),
257 SignedInt(ast::TyI16) => val.to_i16() .map(|v| v as Disr),
258 SignedInt(ast::TyI32) => val.to_i32() .map(|v| v as Disr),
259 SignedInt(ast::TyI64) => val.to_i64() .map(|v| v as Disr),
260 UnsignedInt(ast::TyU8) => val.to_u8() .map(|v| v as Disr),
261 UnsignedInt(ast::TyU16) => val.to_u16() .map(|v| v as Disr),
262 UnsignedInt(ast::TyU32) => val.to_u32() .map(|v| v as Disr),
263 UnsignedInt(ast::TyU64) => val.to_u64() .map(|v| v as Disr),
265 UnsignedInt(ast::TyUs) |
266 SignedInt(ast::TyIs) => unreachable!(),
270 fn disr_incr(&self, val: Disr) -> Option<Disr> {
272 ($e:expr) => { $e.and_then(|v|v.checked_add(1)).map(|v| v as Disr) }
275 // SignedInt repr means we *want* to reinterpret the bits
276 // treating the highest bit of Disr as a sign-bit, so
277 // cast to i64 before range-checking.
278 SignedInt(ast::TyI8) => add1!((val as i64).to_i8()),
279 SignedInt(ast::TyI16) => add1!((val as i64).to_i16()),
280 SignedInt(ast::TyI32) => add1!((val as i64).to_i32()),
281 SignedInt(ast::TyI64) => add1!(Some(val as i64)),
283 UnsignedInt(ast::TyU8) => add1!(val.to_u8()),
284 UnsignedInt(ast::TyU16) => add1!(val.to_u16()),
285 UnsignedInt(ast::TyU32) => add1!(val.to_u32()),
286 UnsignedInt(ast::TyU64) => add1!(Some(val)),
288 UnsignedInt(ast::TyUs) |
289 SignedInt(ast::TyIs) => unreachable!(),
293 // This returns a String because (1.) it is only used for
294 // rendering an error message and (2.) a string can represent the
295 // full range from `i64::MIN` through `u64::MAX`.
296 fn disr_string(&self, val: Disr) -> String {
298 SignedInt(ast::TyI8) => format!("{}", val as i8 ),
299 SignedInt(ast::TyI16) => format!("{}", val as i16),
300 SignedInt(ast::TyI32) => format!("{}", val as i32),
301 SignedInt(ast::TyI64) => format!("{}", val as i64),
302 UnsignedInt(ast::TyU8) => format!("{}", val as u8 ),
303 UnsignedInt(ast::TyU16) => format!("{}", val as u16),
304 UnsignedInt(ast::TyU32) => format!("{}", val as u32),
305 UnsignedInt(ast::TyU64) => format!("{}", val as u64),
307 UnsignedInt(ast::TyUs) |
308 SignedInt(ast::TyIs) => unreachable!(),
312 fn disr_wrap_incr(&self, val: Option<Disr>) -> Disr {
314 ($e:expr) => { ($e).wrapping_add(1) as Disr }
316 let val = val.unwrap_or(ty::INITIAL_DISCRIMINANT_VALUE);
318 SignedInt(ast::TyI8) => add1!(val as i8 ),
319 SignedInt(ast::TyI16) => add1!(val as i16),
320 SignedInt(ast::TyI32) => add1!(val as i32),
321 SignedInt(ast::TyI64) => add1!(val as i64),
322 UnsignedInt(ast::TyU8) => add1!(val as u8 ),
323 UnsignedInt(ast::TyU16) => add1!(val as u16),
324 UnsignedInt(ast::TyU32) => add1!(val as u32),
325 UnsignedInt(ast::TyU64) => add1!(val as u64),
327 UnsignedInt(ast::TyUs) |
328 SignedInt(ast::TyIs) => unreachable!(),
333 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
334 pub enum ImplOrTraitItemContainer {
335 TraitContainer(ast::DefId),
336 ImplContainer(ast::DefId),
339 impl ImplOrTraitItemContainer {
340 pub fn id(&self) -> ast::DefId {
342 TraitContainer(id) => id,
343 ImplContainer(id) => id,
349 pub enum ImplOrTraitItem<'tcx> {
350 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
351 MethodTraitItem(Rc<Method<'tcx>>),
352 TypeTraitItem(Rc<AssociatedType<'tcx>>),
355 impl<'tcx> ImplOrTraitItem<'tcx> {
356 fn id(&self) -> ImplOrTraitItemId {
358 ConstTraitItem(ref associated_const) => {
359 ConstTraitItemId(associated_const.def_id)
361 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
362 TypeTraitItem(ref associated_type) => {
363 TypeTraitItemId(associated_type.def_id)
368 pub fn def_id(&self) -> ast::DefId {
370 ConstTraitItem(ref associated_const) => associated_const.def_id,
371 MethodTraitItem(ref method) => method.def_id,
372 TypeTraitItem(ref associated_type) => associated_type.def_id,
376 pub fn name(&self) -> ast::Name {
378 ConstTraitItem(ref associated_const) => associated_const.name,
379 MethodTraitItem(ref method) => method.name,
380 TypeTraitItem(ref associated_type) => associated_type.name,
384 pub fn vis(&self) -> ast::Visibility {
386 ConstTraitItem(ref associated_const) => associated_const.vis,
387 MethodTraitItem(ref method) => method.vis,
388 TypeTraitItem(ref associated_type) => associated_type.vis,
392 pub fn container(&self) -> ImplOrTraitItemContainer {
394 ConstTraitItem(ref associated_const) => associated_const.container,
395 MethodTraitItem(ref method) => method.container,
396 TypeTraitItem(ref associated_type) => associated_type.container,
400 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
402 MethodTraitItem(ref m) => Some((*m).clone()),
408 #[derive(Clone, Copy, Debug)]
409 pub enum ImplOrTraitItemId {
410 ConstTraitItemId(ast::DefId),
411 MethodTraitItemId(ast::DefId),
412 TypeTraitItemId(ast::DefId),
415 impl ImplOrTraitItemId {
416 pub fn def_id(&self) -> ast::DefId {
418 ConstTraitItemId(def_id) => def_id,
419 MethodTraitItemId(def_id) => def_id,
420 TypeTraitItemId(def_id) => def_id,
425 #[derive(Clone, Debug)]
426 pub struct Method<'tcx> {
428 pub generics: Generics<'tcx>,
429 pub predicates: GenericPredicates<'tcx>,
430 pub fty: BareFnTy<'tcx>,
431 pub explicit_self: ExplicitSelfCategory,
432 pub vis: ast::Visibility,
433 pub def_id: ast::DefId,
434 pub container: ImplOrTraitItemContainer,
436 // If this method is provided, we need to know where it came from
437 pub provided_source: Option<ast::DefId>
440 impl<'tcx> Method<'tcx> {
441 pub fn new(name: ast::Name,
442 generics: ty::Generics<'tcx>,
443 predicates: GenericPredicates<'tcx>,
445 explicit_self: ExplicitSelfCategory,
446 vis: ast::Visibility,
448 container: ImplOrTraitItemContainer,
449 provided_source: Option<ast::DefId>)
454 predicates: predicates,
456 explicit_self: explicit_self,
459 container: container,
460 provided_source: provided_source
464 pub fn container_id(&self) -> ast::DefId {
465 match self.container {
466 TraitContainer(id) => id,
467 ImplContainer(id) => id,
472 #[derive(Clone, Copy, Debug)]
473 pub struct AssociatedConst<'tcx> {
476 pub vis: ast::Visibility,
477 pub def_id: ast::DefId,
478 pub container: ImplOrTraitItemContainer,
479 pub default: Option<ast::DefId>,
482 #[derive(Clone, Copy, Debug)]
483 pub struct AssociatedType<'tcx> {
485 pub ty: Option<Ty<'tcx>>,
486 pub vis: ast::Visibility,
487 pub def_id: ast::DefId,
488 pub container: ImplOrTraitItemContainer,
491 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
492 pub struct TypeAndMut<'tcx> {
494 pub mutbl: ast::Mutability,
497 #[derive(Clone, Copy, Debug)]
501 pub vis: ast::Visibility,
502 pub origin: ast::DefId, // The DefId of the struct in which the field is declared.
505 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
506 pub struct ItemVariances {
507 pub types: VecPerParamSpace<Variance>,
508 pub regions: VecPerParamSpace<Variance>,
511 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
513 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
514 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
515 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
516 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
519 impl fmt::Debug for Variance {
520 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
521 f.write_str(match *self {
523 Contravariant => "-",
530 #[derive(Copy, Clone)]
531 pub enum AutoAdjustment<'tcx> {
532 AdjustReifyFnPointer, // go from a fn-item type to a fn-pointer type
533 AdjustUnsafeFnPointer, // go from a safe fn pointer to an unsafe fn pointer
534 AdjustDerefRef(AutoDerefRef<'tcx>),
537 /// Represents coercing a pointer to a different kind of pointer - where 'kind'
538 /// here means either or both of raw vs borrowed vs unique and fat vs thin.
540 /// We transform pointers by following the following steps in order:
541 /// 1. Deref the pointer `self.autoderefs` times (may be 0).
542 /// 2. If `autoref` is `Some(_)`, then take the address and produce either a
543 /// `&` or `*` pointer.
544 /// 3. If `unsize` is `Some(_)`, then apply the unsize transformation,
545 /// which will do things like convert thin pointers to fat
546 /// pointers, or convert structs containing thin pointers to
547 /// structs containing fat pointers, or convert between fat
548 /// pointers. We don't store the details of how the transform is
549 /// done (in fact, we don't know that, because it might depend on
550 /// the precise type parameters). We just store the target
551 /// type. Trans figures out what has to be done at monomorphization
552 /// time based on the precise source/target type at hand.
554 /// To make that more concrete, here are some common scenarios:
556 /// 1. The simplest cases are where the pointer is not adjusted fat vs thin.
557 /// Here the pointer will be dereferenced N times (where a dereference can
558 /// happen to to raw or borrowed pointers or any smart pointer which implements
559 /// Deref, including Box<_>). The number of dereferences is given by
560 /// `autoderefs`. It can then be auto-referenced zero or one times, indicated
561 /// by `autoref`, to either a raw or borrowed pointer. In these cases unsize is
564 /// 2. A thin-to-fat coercon involves unsizing the underlying data. We start
565 /// with a thin pointer, deref a number of times, unsize the underlying data,
566 /// then autoref. The 'unsize' phase may change a fixed length array to a
567 /// dynamically sized one, a concrete object to a trait object, or statically
568 /// sized struct to a dyncamically sized one. E.g., &[i32; 4] -> &[i32] is
573 /// autoderefs: 1, // &[i32; 4] -> [i32; 4]
574 /// autoref: Some(AutoPtr), // [i32] -> &[i32]
575 /// unsize: Some([i32]), // [i32; 4] -> [i32]
579 /// Note that for a struct, the 'deep' unsizing of the struct is not recorded.
580 /// E.g., `struct Foo<T> { x: T }` we can coerce &Foo<[i32; 4]> to &Foo<[i32]>
581 /// The autoderef and -ref are the same as in the above example, but the type
582 /// stored in `unsize` is `Foo<[i32]>`, we don't store any further detail about
583 /// the underlying conversions from `[i32; 4]` to `[i32]`.
585 /// 3. Coercing a `Box<T>` to `Box<Trait>` is an interesting special case. In
586 /// that case, we have the pointer we need coming in, so there are no
587 /// autoderefs, and no autoref. Instead we just do the `Unsize` transformation.
588 /// At some point, of course, `Box` should move out of the compiler, in which
589 /// case this is analogous to transformating a struct. E.g., Box<[i32; 4]> ->
590 /// Box<[i32]> is represented by:
596 /// unsize: Some(Box<[i32]>),
599 #[derive(Copy, Clone)]
600 pub struct AutoDerefRef<'tcx> {
601 /// Step 1. Apply a number of dereferences, producing an lvalue.
602 pub autoderefs: usize,
604 /// Step 2. Optionally produce a pointer/reference from the value.
605 pub autoref: Option<AutoRef<'tcx>>,
607 /// Step 3. Unsize a pointer/reference value, e.g. `&[T; n]` to
608 /// `&[T]`. The stored type is the target pointer type. Note that
609 /// the source could be a thin or fat pointer.
610 pub unsize: Option<Ty<'tcx>>,
613 #[derive(Copy, Clone, PartialEq, Debug)]
614 pub enum AutoRef<'tcx> {
615 /// Convert from T to &T.
616 AutoPtr(&'tcx Region, ast::Mutability),
618 /// Convert from T to *T.
619 /// Value to thin pointer.
620 AutoUnsafe(ast::Mutability),
623 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)]
624 pub enum CustomCoerceUnsized {
625 /// Records the index of the field being coerced.
629 #[derive(Clone, Copy, Debug)]
630 pub struct MethodCallee<'tcx> {
631 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
632 pub def_id: ast::DefId,
634 pub substs: &'tcx subst::Substs<'tcx>
637 /// With method calls, we store some extra information in
638 /// side tables (i.e method_map). We use
639 /// MethodCall as a key to index into these tables instead of
640 /// just directly using the expression's NodeId. The reason
641 /// for this being that we may apply adjustments (coercions)
642 /// with the resulting expression also needing to use the
643 /// side tables. The problem with this is that we don't
644 /// assign a separate NodeId to this new expression
645 /// and so it would clash with the base expression if both
646 /// needed to add to the side tables. Thus to disambiguate
647 /// we also keep track of whether there's an adjustment in
649 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
650 pub struct MethodCall {
651 pub expr_id: ast::NodeId,
656 pub fn expr(id: ast::NodeId) -> MethodCall {
663 pub fn autoderef(expr_id: ast::NodeId, autoderef: u32) -> MethodCall {
666 autoderef: 1 + autoderef
671 // maps from an expression id that corresponds to a method call to the details
672 // of the method to be invoked
673 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
675 // Contains information needed to resolve types and (in the future) look up
676 // the types of AST nodes.
677 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
678 pub struct CReaderCacheKey {
684 /// A restriction that certain types must be the same size. The use of
685 /// `transmute` gives rise to these restrictions. These generally
686 /// cannot be checked until trans; therefore, each call to `transmute`
687 /// will push one or more such restriction into the
688 /// `transmute_restrictions` vector during `intrinsicck`. They are
689 /// then checked during `trans` by the fn `check_intrinsics`.
690 #[derive(Copy, Clone)]
691 pub struct TransmuteRestriction<'tcx> {
692 /// The span whence the restriction comes.
695 /// The type being transmuted from.
696 pub original_from: Ty<'tcx>,
698 /// The type being transmuted to.
699 pub original_to: Ty<'tcx>,
701 /// The type being transmuted from, with all type parameters
702 /// substituted for an arbitrary representative. Not to be shown
704 pub substituted_from: Ty<'tcx>,
706 /// The type being transmuted to, with all type parameters
707 /// substituted for an arbitrary representative. Not to be shown
709 pub substituted_to: Ty<'tcx>,
711 /// NodeId of the transmute intrinsic.
716 pub struct CtxtArenas<'tcx> {
718 type_: TypedArena<TyS<'tcx>>,
719 substs: TypedArena<Substs<'tcx>>,
720 bare_fn: TypedArena<BareFnTy<'tcx>>,
721 region: TypedArena<Region>,
722 stability: TypedArena<attr::Stability>,
725 trait_defs: TypedArena<TraitDef<'tcx>>,
728 impl<'tcx> CtxtArenas<'tcx> {
729 pub fn new() -> CtxtArenas<'tcx> {
731 type_: TypedArena::new(),
732 substs: TypedArena::new(),
733 bare_fn: TypedArena::new(),
734 region: TypedArena::new(),
735 stability: TypedArena::new(),
737 trait_defs: TypedArena::new()
742 pub struct CommonTypes<'tcx> {
760 pub struct Tables<'tcx> {
761 /// Stores the types for various nodes in the AST. Note that this table
762 /// is not guaranteed to be populated until after typeck. See
763 /// typeck::check::fn_ctxt for details.
764 pub node_types: NodeMap<Ty<'tcx>>,
766 /// Stores the type parameters which were substituted to obtain the type
767 /// of this node. This only applies to nodes that refer to entities
768 /// parameterized by type parameters, such as generic fns, types, or
770 pub item_substs: NodeMap<ItemSubsts<'tcx>>,
772 pub adjustments: NodeMap<ty::AutoAdjustment<'tcx>>,
774 pub method_map: MethodMap<'tcx>,
777 pub upvar_capture_map: UpvarCaptureMap,
779 /// Records the type of each closure. The def ID is the ID of the
780 /// expression defining the closure.
781 pub closure_tys: DefIdMap<ClosureTy<'tcx>>,
783 /// Records the type of each closure. The def ID is the ID of the
784 /// expression defining the closure.
785 pub closure_kinds: DefIdMap<ClosureKind>,
788 impl<'tcx> Tables<'tcx> {
789 pub fn empty() -> Tables<'tcx> {
791 node_types: FnvHashMap(),
792 item_substs: NodeMap(),
793 adjustments: NodeMap(),
794 method_map: FnvHashMap(),
795 upvar_capture_map: FnvHashMap(),
796 closure_tys: DefIdMap(),
797 closure_kinds: DefIdMap(),
802 /// The data structure to keep track of all the information that typechecker
803 /// generates so that so that it can be reused and doesn't have to be redone
805 pub struct ctxt<'tcx> {
806 /// The arenas that types etc are allocated from.
807 arenas: &'tcx CtxtArenas<'tcx>,
809 /// Specifically use a speedy hash algorithm for this hash map, it's used
811 // FIXME(eddyb) use a FnvHashSet<InternedTy<'tcx>> when equivalent keys can
812 // queried from a HashSet.
813 interner: RefCell<FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>>,
815 // FIXME as above, use a hashset if equivalent elements can be queried.
816 substs_interner: RefCell<FnvHashMap<&'tcx Substs<'tcx>, &'tcx Substs<'tcx>>>,
817 bare_fn_interner: RefCell<FnvHashMap<&'tcx BareFnTy<'tcx>, &'tcx BareFnTy<'tcx>>>,
818 region_interner: RefCell<FnvHashMap<&'tcx Region, &'tcx Region>>,
819 stability_interner: RefCell<FnvHashMap<&'tcx attr::Stability, &'tcx attr::Stability>>,
821 /// Common types, pre-interned for your convenience.
822 pub types: CommonTypes<'tcx>,
827 pub named_region_map: resolve_lifetime::NamedRegionMap,
829 pub region_maps: RegionMaps,
831 // For each fn declared in the local crate, type check stores the
832 // free-region relationships that were deduced from its where
833 // clauses and parameter types. These are then read-again by
834 // borrowck. (They are not used during trans, and hence are not
835 // serialized or needed for cross-crate fns.)
836 free_region_maps: RefCell<NodeMap<FreeRegionMap>>,
837 // FIXME: jroesch make this a refcell
839 pub tables: RefCell<Tables<'tcx>>,
841 /// Maps from a trait item to the trait item "descriptor"
842 pub impl_or_trait_items: RefCell<DefIdMap<ImplOrTraitItem<'tcx>>>,
844 /// Maps from a trait def-id to a list of the def-ids of its trait items
845 pub trait_item_def_ids: RefCell<DefIdMap<Rc<Vec<ImplOrTraitItemId>>>>,
847 /// A cache for the trait_items() routine
848 pub trait_items_cache: RefCell<DefIdMap<Rc<Vec<ImplOrTraitItem<'tcx>>>>>,
850 pub impl_trait_refs: RefCell<DefIdMap<Option<TraitRef<'tcx>>>>,
851 pub trait_defs: RefCell<DefIdMap<&'tcx TraitDef<'tcx>>>,
853 /// Maps from the def-id of an item (trait/struct/enum/fn) to its
854 /// associated predicates.
855 pub predicates: RefCell<DefIdMap<GenericPredicates<'tcx>>>,
857 /// Maps from the def-id of a trait to the list of
858 /// super-predicates. This is a subset of the full list of
859 /// predicates. We store these in a separate map because we must
860 /// evaluate them even during type conversion, often before the
861 /// full predicates are available (note that supertraits have
862 /// additional acyclicity requirements).
863 pub super_predicates: RefCell<DefIdMap<GenericPredicates<'tcx>>>,
865 pub map: ast_map::Map<'tcx>,
866 pub freevars: RefCell<FreevarMap>,
867 pub tcache: RefCell<DefIdMap<TypeScheme<'tcx>>>,
868 pub rcache: RefCell<FnvHashMap<CReaderCacheKey, Ty<'tcx>>>,
869 pub tc_cache: RefCell<FnvHashMap<Ty<'tcx>, TypeContents>>,
870 pub ast_ty_to_ty_cache: RefCell<NodeMap<Ty<'tcx>>>,
871 pub enum_var_cache: RefCell<DefIdMap<Rc<Vec<Rc<VariantInfo<'tcx>>>>>>,
872 pub ty_param_defs: RefCell<NodeMap<TypeParameterDef<'tcx>>>,
873 pub normalized_cache: RefCell<FnvHashMap<Ty<'tcx>, Ty<'tcx>>>,
874 pub lang_items: middle::lang_items::LanguageItems,
875 /// A mapping of fake provided method def_ids to the default implementation
876 pub provided_method_sources: RefCell<DefIdMap<ast::DefId>>,
877 pub struct_fields: RefCell<DefIdMap<Rc<Vec<FieldTy>>>>,
879 /// Maps from def-id of a type or region parameter to its
880 /// (inferred) variance.
881 pub item_variance_map: RefCell<DefIdMap<Rc<ItemVariances>>>,
883 /// True if the variance has been computed yet; false otherwise.
884 pub variance_computed: Cell<bool>,
886 /// A mapping from the def ID of an enum or struct type to the def ID
887 /// of the method that implements its destructor. If the type is not
888 /// present in this map, it does not have a destructor. This map is
889 /// populated during the coherence phase of typechecking.
890 pub destructor_for_type: RefCell<DefIdMap<ast::DefId>>,
892 /// A method will be in this list if and only if it is a destructor.
893 pub destructors: RefCell<DefIdSet>,
895 /// Maps a DefId of a type to a list of its inherent impls.
896 /// Contains implementations of methods that are inherent to a type.
897 /// Methods in these implementations don't need to be exported.
898 pub inherent_impls: RefCell<DefIdMap<Rc<Vec<ast::DefId>>>>,
900 /// Maps a DefId of an impl to a list of its items.
901 /// Note that this contains all of the impls that we know about,
902 /// including ones in other crates. It's not clear that this is the best
904 pub impl_items: RefCell<DefIdMap<Vec<ImplOrTraitItemId>>>,
906 /// Set of used unsafe nodes (functions or blocks). Unsafe nodes not
907 /// present in this set can be warned about.
908 pub used_unsafe: RefCell<NodeSet>,
910 /// Set of nodes which mark locals as mutable which end up getting used at
911 /// some point. Local variable definitions not in this set can be warned
913 pub used_mut_nodes: RefCell<NodeSet>,
915 /// The set of external nominal types whose implementations have been read.
916 /// This is used for lazy resolution of methods.
917 pub populated_external_types: RefCell<DefIdSet>,
918 /// The set of external primitive types whose implementations have been read.
919 /// FIXME(arielb1): why is this separate from populated_external_types?
920 pub populated_external_primitive_impls: RefCell<DefIdSet>,
922 /// These caches are used by const_eval when decoding external constants.
923 pub extern_const_statics: RefCell<DefIdMap<ast::NodeId>>,
924 pub extern_const_variants: RefCell<DefIdMap<ast::NodeId>>,
925 pub extern_const_fns: RefCell<DefIdMap<ast::NodeId>>,
927 pub dependency_formats: RefCell<dependency_format::Dependencies>,
929 pub node_lint_levels: RefCell<FnvHashMap<(ast::NodeId, lint::LintId),
932 /// The types that must be asserted to be the same size for `transmute`
933 /// to be valid. We gather up these restrictions in the intrinsicck pass
934 /// and check them in trans.
935 pub transmute_restrictions: RefCell<Vec<TransmuteRestriction<'tcx>>>,
937 /// Maps any item's def-id to its stability index.
938 pub stability: RefCell<stability::Index<'tcx>>,
940 /// Caches the results of trait selection. This cache is used
941 /// for things that do not have to do with the parameters in scope.
942 pub selection_cache: traits::SelectionCache<'tcx>,
944 /// A set of predicates that have been fulfilled *somewhere*.
945 /// This is used to avoid duplicate work. Predicates are only
946 /// added to this set when they mention only "global" names
947 /// (i.e., no type or lifetime parameters).
948 pub fulfilled_predicates: RefCell<traits::FulfilledPredicates<'tcx>>,
950 /// Caches the representation hints for struct definitions.
951 pub repr_hint_cache: RefCell<DefIdMap<Rc<Vec<attr::ReprAttr>>>>,
953 /// Maps Expr NodeId's to their constant qualification.
954 pub const_qualif_map: RefCell<NodeMap<check_const::ConstQualif>>,
956 /// Caches CoerceUnsized kinds for impls on custom types.
957 pub custom_coerce_unsized_kinds: RefCell<DefIdMap<CustomCoerceUnsized>>,
959 /// Maps a cast expression to its kind. This is keyed on the
960 /// *from* expression of the cast, not the cast itself.
961 pub cast_kinds: RefCell<NodeMap<cast::CastKind>>,
964 impl<'tcx> ctxt<'tcx> {
965 pub fn node_types(&self) -> Ref<NodeMap<Ty<'tcx>>> {
966 fn projection<'a, 'tcx>(tables: &'a Tables<'tcx>) -> &'a NodeMap<Ty<'tcx>> {
970 Ref::map(self.tables.borrow(), projection)
973 pub fn node_type_insert(&self, id: NodeId, ty: Ty<'tcx>) {
974 self.tables.borrow_mut().node_types.insert(id, ty);
977 pub fn intern_trait_def(&self, def: TraitDef<'tcx>) -> &'tcx TraitDef<'tcx> {
978 let did = def.trait_ref.def_id;
979 let interned = self.arenas.trait_defs.alloc(def);
980 self.trait_defs.borrow_mut().insert(did, interned);
984 pub fn intern_stability(&self, stab: attr::Stability) -> &'tcx attr::Stability {
985 if let Some(st) = self.stability_interner.borrow().get(&stab) {
989 let interned = self.arenas.stability.alloc(stab);
990 self.stability_interner.borrow_mut().insert(interned, interned);
994 pub fn store_free_region_map(&self, id: NodeId, map: FreeRegionMap) {
995 self.free_region_maps.borrow_mut()
999 pub fn free_region_map(&self, id: NodeId) -> FreeRegionMap {
1000 self.free_region_maps.borrow()[&id].clone()
1003 pub fn lift<T: ?Sized + Lift<'tcx>>(&self, value: &T) -> Option<T::Lifted> {
1004 value.lift_to_tcx(self)
1008 /// A trait implemented for all X<'a> types which can be safely and
1009 /// efficiently converted to X<'tcx> as long as they are part of the
1010 /// provided ty::ctxt<'tcx>.
1011 /// This can be done, for example, for Ty<'tcx> or &'tcx Substs<'tcx>
1012 /// by looking them up in their respective interners.
1013 /// None is returned if the value or one of the components is not part
1014 /// of the provided context.
1015 /// For Ty, None can be returned if either the type interner doesn't
1016 /// contain the TypeVariants key or if the address of the interned
1017 /// pointer differs. The latter case is possible if a primitive type,
1018 /// e.g. `()` or `u8`, was interned in a different context.
1019 pub trait Lift<'tcx> {
1021 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted>;
1024 impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>> Lift<'tcx> for (A, B) {
1025 type Lifted = (A::Lifted, B::Lifted);
1026 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1027 tcx.lift(&self.0).and_then(|a| tcx.lift(&self.1).map(|b| (a, b)))
1031 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for [T] {
1032 type Lifted = Vec<T::Lifted>;
1033 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1034 let mut result = Vec::with_capacity(self.len());
1036 if let Some(value) = tcx.lift(x) {
1046 impl<'tcx> Lift<'tcx> for Region {
1048 fn lift_to_tcx(&self, _: &ctxt<'tcx>) -> Option<Region> {
1053 impl<'a, 'tcx> Lift<'tcx> for Ty<'a> {
1054 type Lifted = Ty<'tcx>;
1055 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Ty<'tcx>> {
1056 if let Some(&ty) = tcx.interner.borrow().get(&self.sty) {
1057 if *self as *const _ == ty as *const _ {
1065 impl<'a, 'tcx> Lift<'tcx> for &'a Substs<'a> {
1066 type Lifted = &'tcx Substs<'tcx>;
1067 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<&'tcx Substs<'tcx>> {
1068 if let Some(&substs) = tcx.substs_interner.borrow().get(*self) {
1069 if *self as *const _ == substs as *const _ {
1070 return Some(substs);
1077 impl<'a, 'tcx> Lift<'tcx> for TraitRef<'a> {
1078 type Lifted = TraitRef<'tcx>;
1079 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<TraitRef<'tcx>> {
1080 tcx.lift(&self.substs).map(|substs| TraitRef {
1081 def_id: self.def_id,
1087 impl<'a, 'tcx> Lift<'tcx> for TraitPredicate<'a> {
1088 type Lifted = TraitPredicate<'tcx>;
1089 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<TraitPredicate<'tcx>> {
1090 tcx.lift(&self.trait_ref).map(|trait_ref| TraitPredicate {
1091 trait_ref: trait_ref
1096 impl<'a, 'tcx> Lift<'tcx> for EquatePredicate<'a> {
1097 type Lifted = EquatePredicate<'tcx>;
1098 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<EquatePredicate<'tcx>> {
1099 tcx.lift(&(self.0, self.1)).map(|(a, b)| EquatePredicate(a, b))
1103 impl<'tcx, A: Copy+Lift<'tcx>, B: Copy+Lift<'tcx>> Lift<'tcx> for OutlivesPredicate<A, B> {
1104 type Lifted = OutlivesPredicate<A::Lifted, B::Lifted>;
1105 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1106 tcx.lift(&(self.0, self.1)).map(|(a, b)| OutlivesPredicate(a, b))
1110 impl<'a, 'tcx> Lift<'tcx> for ProjectionPredicate<'a> {
1111 type Lifted = ProjectionPredicate<'tcx>;
1112 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<ProjectionPredicate<'tcx>> {
1113 tcx.lift(&(self.projection_ty.trait_ref, self.ty)).map(|(trait_ref, ty)| {
1114 ProjectionPredicate {
1115 projection_ty: ProjectionTy {
1116 trait_ref: trait_ref,
1117 item_name: self.projection_ty.item_name
1125 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Binder<T> {
1126 type Lifted = Binder<T::Lifted>;
1127 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1128 tcx.lift(&self.0).map(|x| Binder(x))
1135 use session::Session;
1139 use syntax::codemap;
1141 /// Marker type used for the scoped TLS slot.
1142 /// The type context cannot be used directly because the scoped TLS
1143 /// in libstd doesn't allow types generic over lifetimes.
1144 struct ThreadLocalTyCx;
1146 scoped_thread_local!(static TLS_TCX: ThreadLocalTyCx);
1148 fn def_id_debug(def_id: ast::DefId, f: &mut fmt::Formatter) -> fmt::Result {
1149 // Unfortunately, there seems to be no way to attempt to print
1150 // a path for a def-id, so I'll just make a best effort for now
1151 // and otherwise fallback to just printing the crate/node pair
1153 if def_id.krate == ast::LOCAL_CRATE {
1154 match tcx.map.find(def_id.node) {
1155 Some(ast_map::NodeItem(..)) |
1156 Some(ast_map::NodeForeignItem(..)) |
1157 Some(ast_map::NodeImplItem(..)) |
1158 Some(ast_map::NodeTraitItem(..)) |
1159 Some(ast_map::NodeVariant(..)) |
1160 Some(ast_map::NodeStructCtor(..)) => {
1161 return write!(f, "{}", tcx.item_path_str(def_id));
1170 fn span_debug(span: codemap::Span, f: &mut fmt::Formatter) -> fmt::Result {
1172 write!(f, "{}", tcx.sess.codemap().span_to_string(span))
1176 pub fn enter<'tcx, F: FnOnce(&ty::ctxt<'tcx>) -> R, R>(tcx: ty::ctxt<'tcx>, f: F)
1178 let result = ast::DEF_ID_DEBUG.with(|def_id_dbg| {
1179 codemap::SPAN_DEBUG.with(|span_dbg| {
1180 let original_def_id_debug = def_id_dbg.get();
1181 def_id_dbg.set(def_id_debug);
1182 let original_span_debug = span_dbg.get();
1183 span_dbg.set(span_debug);
1184 let tls_ptr = &tcx as *const _ as *const ThreadLocalTyCx;
1185 let result = TLS_TCX.set(unsafe { &*tls_ptr }, || f(&tcx));
1186 def_id_dbg.set(original_def_id_debug);
1187 span_dbg.set(original_span_debug);
1194 pub fn with<F: FnOnce(&ty::ctxt) -> R, R>(f: F) -> R {
1195 TLS_TCX.with(|tcx| f(unsafe { &*(tcx as *const _ as *const ty::ctxt) }))
1199 // Flags that we track on types. These flags are propagated upwards
1200 // through the type during type construction, so that we can quickly
1201 // check whether the type has various kinds of types in it without
1202 // recursing over the type itself.
1204 flags TypeFlags: u32 {
1205 const HAS_PARAMS = 1 << 0,
1206 const HAS_SELF = 1 << 1,
1207 const HAS_TY_INFER = 1 << 2,
1208 const HAS_RE_INFER = 1 << 3,
1209 const HAS_RE_EARLY_BOUND = 1 << 4,
1210 const HAS_FREE_REGIONS = 1 << 5,
1211 const HAS_TY_ERR = 1 << 6,
1212 const HAS_PROJECTION = 1 << 7,
1213 const HAS_TY_CLOSURE = 1 << 8,
1215 // true if there are "names" of types and regions and so forth
1216 // that are local to a particular fn
1217 const HAS_LOCAL_NAMES = 1 << 9,
1219 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
1220 TypeFlags::HAS_SELF.bits |
1221 TypeFlags::HAS_RE_EARLY_BOUND.bits,
1223 // Flags representing the nominal content of a type,
1224 // computed by FlagsComputation. If you add a new nominal
1225 // flag, it should be added here too.
1226 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
1227 TypeFlags::HAS_SELF.bits |
1228 TypeFlags::HAS_TY_INFER.bits |
1229 TypeFlags::HAS_RE_INFER.bits |
1230 TypeFlags::HAS_RE_EARLY_BOUND.bits |
1231 TypeFlags::HAS_FREE_REGIONS.bits |
1232 TypeFlags::HAS_TY_ERR.bits |
1233 TypeFlags::HAS_PROJECTION.bits |
1234 TypeFlags::HAS_TY_CLOSURE.bits |
1235 TypeFlags::HAS_LOCAL_NAMES.bits,
1237 // Caches for type_is_sized, type_moves_by_default
1238 const SIZEDNESS_CACHED = 1 << 16,
1239 const IS_SIZED = 1 << 17,
1240 const MOVENESS_CACHED = 1 << 18,
1241 const MOVES_BY_DEFAULT = 1 << 19,
1245 macro_rules! sty_debug_print {
1246 ($ctxt: expr, $($variant: ident),*) => {{
1247 // curious inner module to allow variant names to be used as
1249 #[allow(non_snake_case)]
1252 #[derive(Copy, Clone)]
1255 region_infer: usize,
1260 pub fn go(tcx: &ty::ctxt) {
1261 let mut total = DebugStat {
1263 region_infer: 0, ty_infer: 0, both_infer: 0,
1265 $(let mut $variant = total;)*
1268 for (_, t) in tcx.interner.borrow().iter() {
1269 let variant = match t.sty {
1270 ty::TyBool | ty::TyChar | ty::TyInt(..) | ty::TyUint(..) |
1271 ty::TyFloat(..) | ty::TyStr => continue,
1272 ty::TyError => /* unimportant */ continue,
1273 $(ty::$variant(..) => &mut $variant,)*
1275 let region = t.flags.get().intersects(ty::TypeFlags::HAS_RE_INFER);
1276 let ty = t.flags.get().intersects(ty::TypeFlags::HAS_TY_INFER);
1280 if region { total.region_infer += 1; variant.region_infer += 1 }
1281 if ty { total.ty_infer += 1; variant.ty_infer += 1 }
1282 if region && ty { total.both_infer += 1; variant.both_infer += 1 }
1284 println!("Ty interner total ty region both");
1285 $(println!(" {:18}: {uses:6} {usespc:4.1}%, \
1286 {ty:4.1}% {region:5.1}% {both:4.1}%",
1287 stringify!($variant),
1288 uses = $variant.total,
1289 usespc = $variant.total as f64 * 100.0 / total.total as f64,
1290 ty = $variant.ty_infer as f64 * 100.0 / total.total as f64,
1291 region = $variant.region_infer as f64 * 100.0 / total.total as f64,
1292 both = $variant.both_infer as f64 * 100.0 / total.total as f64);
1294 println!(" total {uses:6} \
1295 {ty:4.1}% {region:5.1}% {both:4.1}%",
1297 ty = total.ty_infer as f64 * 100.0 / total.total as f64,
1298 region = total.region_infer as f64 * 100.0 / total.total as f64,
1299 both = total.both_infer as f64 * 100.0 / total.total as f64)
1307 impl<'tcx> ctxt<'tcx> {
1308 pub fn print_debug_stats(&self) {
1311 TyEnum, TyBox, TyArray, TySlice, TyRawPtr, TyRef, TyBareFn, TyTrait,
1312 TyStruct, TyClosure, TyTuple, TyParam, TyInfer, TyProjection);
1314 println!("Substs interner: #{}", self.substs_interner.borrow().len());
1315 println!("BareFnTy interner: #{}", self.bare_fn_interner.borrow().len());
1316 println!("Region interner: #{}", self.region_interner.borrow().len());
1317 println!("Stability interner: #{}", self.stability_interner.borrow().len());
1321 pub struct TyS<'tcx> {
1322 pub sty: TypeVariants<'tcx>,
1323 pub flags: Cell<TypeFlags>,
1325 // the maximal depth of any bound regions appearing in this type.
1329 impl fmt::Debug for TypeFlags {
1330 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1331 write!(f, "{}", self.bits)
1335 impl<'tcx> PartialEq for TyS<'tcx> {
1337 fn eq(&self, other: &TyS<'tcx>) -> bool {
1338 // (self as *const _) == (other as *const _)
1339 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
1342 impl<'tcx> Eq for TyS<'tcx> {}
1344 impl<'tcx> Hash for TyS<'tcx> {
1345 fn hash<H: Hasher>(&self, s: &mut H) {
1346 (self as *const TyS).hash(s)
1350 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
1352 /// An entry in the type interner.
1353 pub struct InternedTy<'tcx> {
1357 // NB: An InternedTy compares and hashes as a sty.
1358 impl<'tcx> PartialEq for InternedTy<'tcx> {
1359 fn eq(&self, other: &InternedTy<'tcx>) -> bool {
1360 self.ty.sty == other.ty.sty
1364 impl<'tcx> Eq for InternedTy<'tcx> {}
1366 impl<'tcx> Hash for InternedTy<'tcx> {
1367 fn hash<H: Hasher>(&self, s: &mut H) {
1372 impl<'tcx> Borrow<TypeVariants<'tcx>> for InternedTy<'tcx> {
1373 fn borrow<'a>(&'a self) -> &'a TypeVariants<'tcx> {
1378 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
1379 pub struct BareFnTy<'tcx> {
1380 pub unsafety: ast::Unsafety,
1382 pub sig: PolyFnSig<'tcx>,
1385 #[derive(Clone, PartialEq, Eq, Hash)]
1386 pub struct ClosureTy<'tcx> {
1387 pub unsafety: ast::Unsafety,
1389 pub sig: PolyFnSig<'tcx>,
1392 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
1393 pub enum FnOutput<'tcx> {
1394 FnConverging(Ty<'tcx>),
1398 impl<'tcx> FnOutput<'tcx> {
1399 pub fn diverges(&self) -> bool {
1400 *self == FnDiverging
1403 pub fn unwrap(self) -> Ty<'tcx> {
1405 ty::FnConverging(t) => t,
1406 ty::FnDiverging => unreachable!()
1410 pub fn unwrap_or(self, def: Ty<'tcx>) -> Ty<'tcx> {
1412 ty::FnConverging(t) => t,
1413 ty::FnDiverging => def
1418 pub type PolyFnOutput<'tcx> = Binder<FnOutput<'tcx>>;
1420 impl<'tcx> PolyFnOutput<'tcx> {
1421 pub fn diverges(&self) -> bool {
1426 /// Signature of a function type, which I have arbitrarily
1427 /// decided to use to refer to the input/output types.
1429 /// - `inputs` is the list of arguments and their modes.
1430 /// - `output` is the return type.
1431 /// - `variadic` indicates whether this is a variadic function. (only true for foreign fns)
1432 #[derive(Clone, PartialEq, Eq, Hash)]
1433 pub struct FnSig<'tcx> {
1434 pub inputs: Vec<Ty<'tcx>>,
1435 pub output: FnOutput<'tcx>,
1439 pub type PolyFnSig<'tcx> = Binder<FnSig<'tcx>>;
1441 impl<'tcx> PolyFnSig<'tcx> {
1442 pub fn inputs(&self) -> ty::Binder<Vec<Ty<'tcx>>> {
1443 self.map_bound_ref(|fn_sig| fn_sig.inputs.clone())
1445 pub fn input(&self, index: usize) -> ty::Binder<Ty<'tcx>> {
1446 self.map_bound_ref(|fn_sig| fn_sig.inputs[index])
1448 pub fn output(&self) -> ty::Binder<FnOutput<'tcx>> {
1449 self.map_bound_ref(|fn_sig| fn_sig.output.clone())
1451 pub fn variadic(&self) -> bool {
1452 self.skip_binder().variadic
1456 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1457 pub struct ParamTy {
1458 pub space: subst::ParamSpace,
1460 pub name: ast::Name,
1463 /// A [De Bruijn index][dbi] is a standard means of representing
1464 /// regions (and perhaps later types) in a higher-ranked setting. In
1465 /// particular, imagine a type like this:
1467 /// for<'a> fn(for<'b> fn(&'b isize, &'a isize), &'a char)
1470 /// | +------------+ 1 | |
1472 /// +--------------------------------+ 2 |
1474 /// +------------------------------------------+ 1
1476 /// In this type, there are two binders (the outer fn and the inner
1477 /// fn). We need to be able to determine, for any given region, which
1478 /// fn type it is bound by, the inner or the outer one. There are
1479 /// various ways you can do this, but a De Bruijn index is one of the
1480 /// more convenient and has some nice properties. The basic idea is to
1481 /// count the number of binders, inside out. Some examples should help
1482 /// clarify what I mean.
1484 /// Let's start with the reference type `&'b isize` that is the first
1485 /// argument to the inner function. This region `'b` is assigned a De
1486 /// Bruijn index of 1, meaning "the innermost binder" (in this case, a
1487 /// fn). The region `'a` that appears in the second argument type (`&'a
1488 /// isize`) would then be assigned a De Bruijn index of 2, meaning "the
1489 /// second-innermost binder". (These indices are written on the arrays
1490 /// in the diagram).
1492 /// What is interesting is that De Bruijn index attached to a particular
1493 /// variable will vary depending on where it appears. For example,
1494 /// the final type `&'a char` also refers to the region `'a` declared on
1495 /// the outermost fn. But this time, this reference is not nested within
1496 /// any other binders (i.e., it is not an argument to the inner fn, but
1497 /// rather the outer one). Therefore, in this case, it is assigned a
1498 /// De Bruijn index of 1, because the innermost binder in that location
1499 /// is the outer fn.
1501 /// [dbi]: http://en.wikipedia.org/wiki/De_Bruijn_index
1502 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug, Copy)]
1503 pub struct DebruijnIndex {
1504 // We maintain the invariant that this is never 0. So 1 indicates
1505 // the innermost binder. To ensure this, create with `DebruijnIndex::new`.
1509 /// Representation of regions:
1510 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Copy)]
1512 // Region bound in a type or fn declaration which will be
1513 // substituted 'early' -- that is, at the same time when type
1514 // parameters are substituted.
1515 ReEarlyBound(EarlyBoundRegion),
1517 // Region bound in a function scope, which will be substituted when the
1518 // function is called.
1519 ReLateBound(DebruijnIndex, BoundRegion),
1521 /// When checking a function body, the types of all arguments and so forth
1522 /// that refer to bound region parameters are modified to refer to free
1523 /// region parameters.
1526 /// A concrete region naming some statically determined extent
1527 /// (e.g. an expression or sequence of statements) within the
1528 /// current function.
1529 ReScope(region::CodeExtent),
1531 /// Static data that has an "infinite" lifetime. Top in the region lattice.
1534 /// A region variable. Should not exist after typeck.
1535 ReInfer(InferRegion),
1537 /// Empty lifetime is for data that is never accessed.
1538 /// Bottom in the region lattice. We treat ReEmpty somewhat
1539 /// specially; at least right now, we do not generate instances of
1540 /// it during the GLB computations, but rather
1541 /// generate an error instead. This is to improve error messages.
1542 /// The only way to get an instance of ReEmpty is to have a region
1543 /// variable with no constraints.
1547 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug)]
1548 pub struct EarlyBoundRegion {
1549 pub param_id: ast::NodeId,
1550 pub space: subst::ParamSpace,
1552 pub name: ast::Name,
1555 /// Upvars do not get their own node-id. Instead, we use the pair of
1556 /// the original var id (that is, the root variable that is referenced
1557 /// by the upvar) and the id of the closure expression.
1558 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1559 pub struct UpvarId {
1560 pub var_id: ast::NodeId,
1561 pub closure_expr_id: ast::NodeId,
1564 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
1565 pub enum BorrowKind {
1566 /// Data must be immutable and is aliasable.
1569 /// Data must be immutable but not aliasable. This kind of borrow
1570 /// cannot currently be expressed by the user and is used only in
1571 /// implicit closure bindings. It is needed when you the closure
1572 /// is borrowing or mutating a mutable referent, e.g.:
1574 /// let x: &mut isize = ...;
1575 /// let y = || *x += 5;
1577 /// If we were to try to translate this closure into a more explicit
1578 /// form, we'd encounter an error with the code as written:
1580 /// struct Env { x: & &mut isize }
1581 /// let x: &mut isize = ...;
1582 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
1583 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
1585 /// This is then illegal because you cannot mutate a `&mut` found
1586 /// in an aliasable location. To solve, you'd have to translate with
1587 /// an `&mut` borrow:
1589 /// struct Env { x: & &mut isize }
1590 /// let x: &mut isize = ...;
1591 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
1592 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
1594 /// Now the assignment to `**env.x` is legal, but creating a
1595 /// mutable pointer to `x` is not because `x` is not mutable. We
1596 /// could fix this by declaring `x` as `let mut x`. This is ok in
1597 /// user code, if awkward, but extra weird for closures, since the
1598 /// borrow is hidden.
1600 /// So we introduce a "unique imm" borrow -- the referent is
1601 /// immutable, but not aliasable. This solves the problem. For
1602 /// simplicity, we don't give users the way to express this
1603 /// borrow, it's just used when translating closures.
1606 /// Data is mutable and not aliasable.
1610 /// Information describing the capture of an upvar. This is computed
1611 /// during `typeck`, specifically by `regionck`.
1612 #[derive(PartialEq, Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
1613 pub enum UpvarCapture {
1614 /// Upvar is captured by value. This is always true when the
1615 /// closure is labeled `move`, but can also be true in other cases
1616 /// depending on inference.
1619 /// Upvar is captured by reference.
1623 #[derive(PartialEq, Clone, RustcEncodable, RustcDecodable, Copy)]
1624 pub struct UpvarBorrow {
1625 /// The kind of borrow: by-ref upvars have access to shared
1626 /// immutable borrows, which are not part of the normal language
1628 pub kind: BorrowKind,
1630 /// Region of the resulting reference.
1631 pub region: ty::Region,
1634 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
1636 #[derive(Copy, Clone)]
1637 pub struct ClosureUpvar<'tcx> {
1644 pub fn is_bound(&self) -> bool {
1646 ty::ReEarlyBound(..) => true,
1647 ty::ReLateBound(..) => true,
1652 pub fn escapes_depth(&self, depth: u32) -> bool {
1654 ty::ReLateBound(debruijn, _) => debruijn.depth > depth,
1659 /// Returns the depth of `self` from the (1-based) binding level `depth`
1660 pub fn from_depth(&self, depth: u32) -> Region {
1662 ty::ReLateBound(debruijn, r) => ty::ReLateBound(DebruijnIndex {
1663 depth: debruijn.depth - (depth - 1)
1670 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash,
1671 RustcEncodable, RustcDecodable, Copy)]
1672 /// A "free" region `fr` can be interpreted as "some region
1673 /// at least as big as the scope `fr.scope`".
1674 pub struct FreeRegion {
1675 pub scope: region::DestructionScopeData,
1676 pub bound_region: BoundRegion
1679 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash,
1680 RustcEncodable, RustcDecodable, Copy, Debug)]
1681 pub enum BoundRegion {
1682 /// An anonymous region parameter for a given fn (&T)
1685 /// Named region parameters for functions (a in &'a T)
1687 /// The def-id is needed to distinguish free regions in
1688 /// the event of shadowing.
1689 BrNamed(ast::DefId, ast::Name),
1691 /// Fresh bound identifiers created during GLB computations.
1694 // Anonymous region for the implicit env pointer parameter
1699 // NB: If you change this, you'll probably want to change the corresponding
1700 // AST structure in libsyntax/ast.rs as well.
1701 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
1702 pub enum TypeVariants<'tcx> {
1703 /// The primitive boolean type. Written as `bool`.
1706 /// The primitive character type; holds a Unicode scalar value
1707 /// (a non-surrogate code point). Written as `char`.
1710 /// A primitive signed integer type. For example, `i32`.
1713 /// A primitive unsigned integer type. For example, `u32`.
1714 TyUint(ast::UintTy),
1716 /// A primitive floating-point type. For example, `f64`.
1717 TyFloat(ast::FloatTy),
1719 /// An enumerated type, defined with `enum`.
1721 /// Substs here, possibly against intuition, *may* contain `TyParam`s.
1722 /// That is, even after substitution it is possible that there are type
1723 /// variables. This happens when the `TyEnum` corresponds to an enum
1724 /// definition and not a concrete use of it. To get the correct `TyEnum`
1725 /// from the tcx, use the `NodeId` from the `ast::Ty` and look it up in
1726 /// the `ast_ty_to_ty_cache`. This is probably true for `TyStruct` as
1728 TyEnum(DefId, &'tcx Substs<'tcx>),
1730 /// A structure type, defined with `struct`.
1732 /// See warning about substitutions for enumerated types.
1733 TyStruct(DefId, &'tcx Substs<'tcx>),
1735 /// `Box<T>`; this is nominally a struct in the documentation, but is
1736 /// special-cased internally. For example, it is possible to implicitly
1737 /// move the contents of a box out of that box, and methods of any type
1738 /// can have type `Box<Self>`.
1741 /// The pointee of a string slice. Written as `str`.
1744 /// An array with the given length. Written as `[T; n]`.
1745 TyArray(Ty<'tcx>, usize),
1747 /// The pointee of an array slice. Written as `[T]`.
1750 /// A raw pointer. Written as `*mut T` or `*const T`
1751 TyRawPtr(TypeAndMut<'tcx>),
1753 /// A reference; a pointer with an associated lifetime. Written as
1754 /// `&a mut T` or `&'a T`.
1755 TyRef(&'tcx Region, TypeAndMut<'tcx>),
1757 /// If the def-id is Some(_), then this is the type of a specific
1758 /// fn item. Otherwise, if None(_), it a fn pointer type.
1760 /// FIXME: Conflating function pointers and the type of a
1761 /// function is probably a terrible idea; a function pointer is a
1762 /// value with a specific type, but a function can be polymorphic
1763 /// or dynamically dispatched.
1764 TyBareFn(Option<DefId>, &'tcx BareFnTy<'tcx>),
1766 /// A trait, defined with `trait`.
1767 TyTrait(Box<TraitTy<'tcx>>),
1769 /// The anonymous type of a closure. Used to represent the type of
1771 TyClosure(DefId, Box<ClosureSubsts<'tcx>>),
1773 /// A tuple type. For example, `(i32, bool)`.
1774 TyTuple(Vec<Ty<'tcx>>),
1776 /// The projection of an associated type. For example,
1777 /// `<T as Trait<..>>::N`.
1778 TyProjection(ProjectionTy<'tcx>),
1780 /// A type parameter; for example, `T` in `fn f<T>(x: T) {}
1783 /// A type variable used during type-checking.
1786 /// A placeholder for a type which could not be computed; this is
1787 /// propagated to avoid useless error messages.
1791 /// A closure can be modeled as a struct that looks like:
1793 /// struct Closure<'l0...'li, T0...Tj, U0...Uk> {
1799 /// where 'l0...'li and T0...Tj are the lifetime and type parameters
1800 /// in scope on the function that defined the closure, and U0...Uk are
1801 /// type parameters representing the types of its upvars (borrowed, if
1804 /// So, for example, given this function:
1806 /// fn foo<'a, T>(data: &'a mut T) {
1807 /// do(|| data.count += 1)
1810 /// the type of the closure would be something like:
1812 /// struct Closure<'a, T, U0> {
1816 /// Note that the type of the upvar is not specified in the struct.
1817 /// You may wonder how the impl would then be able to use the upvar,
1818 /// if it doesn't know it's type? The answer is that the impl is
1819 /// (conceptually) not fully generic over Closure but rather tied to
1820 /// instances with the expected upvar types:
1822 /// impl<'b, 'a, T> FnMut() for Closure<'a, T, &'b mut &'a mut T> {
1826 /// You can see that the *impl* fully specified the type of the upvar
1827 /// and thus knows full well that `data` has type `&'b mut &'a mut T`.
1828 /// (Here, I am assuming that `data` is mut-borrowed.)
1830 /// Now, the last question you may ask is: Why include the upvar types
1831 /// as extra type parameters? The reason for this design is that the
1832 /// upvar types can reference lifetimes that are internal to the
1833 /// creating function. In my example above, for example, the lifetime
1834 /// `'b` represents the extent of the closure itself; this is some
1835 /// subset of `foo`, probably just the extent of the call to the to
1836 /// `do()`. If we just had the lifetime/type parameters from the
1837 /// enclosing function, we couldn't name this lifetime `'b`. Note that
1838 /// there can also be lifetimes in the types of the upvars themselves,
1839 /// if one of them happens to be a reference to something that the
1840 /// creating fn owns.
1842 /// OK, you say, so why not create a more minimal set of parameters
1843 /// that just includes the extra lifetime parameters? The answer is
1844 /// primarily that it would be hard --- we don't know at the time when
1845 /// we create the closure type what the full types of the upvars are,
1846 /// nor do we know which are borrowed and which are not. In this
1847 /// design, we can just supply a fresh type parameter and figure that
1850 /// All right, you say, but why include the type parameters from the
1851 /// original function then? The answer is that trans may need them
1852 /// when monomorphizing, and they may not appear in the upvars. A
1853 /// closure could capture no variables but still make use of some
1854 /// in-scope type parameter with a bound (e.g., if our example above
1855 /// had an extra `U: Default`, and the closure called `U::default()`).
1857 /// There is another reason. This design (implicitly) prohibits
1858 /// closures from capturing themselves (except via a trait
1859 /// object). This simplifies closure inference considerably, since it
1860 /// means that when we infer the kind of a closure or its upvars, we
1861 /// don't have to handle cycles where the decisions we make for
1862 /// closure C wind up influencing the decisions we ought to make for
1863 /// closure C (which would then require fixed point iteration to
1864 /// handle). Plus it fixes an ICE. :P
1865 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
1866 pub struct ClosureSubsts<'tcx> {
1867 /// Lifetime and type parameters from the enclosing function.
1868 /// These are separated out because trans wants to pass them around
1869 /// when monomorphizing.
1870 pub func_substs: &'tcx Substs<'tcx>,
1872 /// The types of the upvars. The list parallels the freevars and
1873 /// `upvar_borrows` lists. These are kept distinct so that we can
1874 /// easily index into them.
1875 pub upvar_tys: Vec<Ty<'tcx>>
1878 #[derive(Clone, PartialEq, Eq, Hash)]
1879 pub struct TraitTy<'tcx> {
1880 pub principal: ty::PolyTraitRef<'tcx>,
1881 pub bounds: ExistentialBounds<'tcx>,
1884 impl<'tcx> TraitTy<'tcx> {
1885 pub fn principal_def_id(&self) -> ast::DefId {
1886 self.principal.0.def_id
1889 /// Object types don't have a self-type specified. Therefore, when
1890 /// we convert the principal trait-ref into a normal trait-ref,
1891 /// you must give *some* self-type. A common choice is `mk_err()`
1892 /// or some skolemized type.
1893 pub fn principal_trait_ref_with_self_ty(&self,
1896 -> ty::PolyTraitRef<'tcx>
1898 // otherwise the escaping regions would be captured by the binder
1899 assert!(!self_ty.has_escaping_regions());
1901 ty::Binder(TraitRef {
1902 def_id: self.principal.0.def_id,
1903 substs: tcx.mk_substs(self.principal.0.substs.with_self_ty(self_ty)),
1907 pub fn projection_bounds_with_self_ty(&self,
1910 -> Vec<ty::PolyProjectionPredicate<'tcx>>
1912 // otherwise the escaping regions would be captured by the binders
1913 assert!(!self_ty.has_escaping_regions());
1915 self.bounds.projection_bounds.iter()
1916 .map(|in_poly_projection_predicate| {
1917 let in_projection_ty = &in_poly_projection_predicate.0.projection_ty;
1918 let substs = tcx.mk_substs(in_projection_ty.trait_ref.substs.with_self_ty(self_ty));
1919 let trait_ref = ty::TraitRef::new(in_projection_ty.trait_ref.def_id,
1921 let projection_ty = ty::ProjectionTy {
1922 trait_ref: trait_ref,
1923 item_name: in_projection_ty.item_name
1925 ty::Binder(ty::ProjectionPredicate {
1926 projection_ty: projection_ty,
1927 ty: in_poly_projection_predicate.0.ty
1934 /// A complete reference to a trait. These take numerous guises in syntax,
1935 /// but perhaps the most recognizable form is in a where clause:
1939 /// This would be represented by a trait-reference where the def-id is the
1940 /// def-id for the trait `Foo` and the substs defines `T` as parameter 0 in the
1941 /// `SelfSpace` and `U` as parameter 0 in the `TypeSpace`.
1943 /// Trait references also appear in object types like `Foo<U>`, but in
1944 /// that case the `Self` parameter is absent from the substitutions.
1946 /// Note that a `TraitRef` introduces a level of region binding, to
1947 /// account for higher-ranked trait bounds like `T : for<'a> Foo<&'a
1948 /// U>` or higher-ranked object types.
1949 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
1950 pub struct TraitRef<'tcx> {
1952 pub substs: &'tcx Substs<'tcx>,
1955 pub type PolyTraitRef<'tcx> = Binder<TraitRef<'tcx>>;
1957 impl<'tcx> PolyTraitRef<'tcx> {
1958 pub fn self_ty(&self) -> Ty<'tcx> {
1962 pub fn def_id(&self) -> ast::DefId {
1966 pub fn substs(&self) -> &'tcx Substs<'tcx> {
1967 // FIXME(#20664) every use of this fn is probably a bug, it should yield Binder<>
1971 pub fn input_types(&self) -> &[Ty<'tcx>] {
1972 // FIXME(#20664) every use of this fn is probably a bug, it should yield Binder<>
1973 self.0.input_types()
1976 pub fn to_poly_trait_predicate(&self) -> PolyTraitPredicate<'tcx> {
1977 // Note that we preserve binding levels
1978 Binder(TraitPredicate { trait_ref: self.0.clone() })
1982 /// Binder is a binder for higher-ranked lifetimes. It is part of the
1983 /// compiler's representation for things like `for<'a> Fn(&'a isize)`
1984 /// (which would be represented by the type `PolyTraitRef ==
1985 /// Binder<TraitRef>`). Note that when we skolemize, instantiate,
1986 /// erase, or otherwise "discharge" these bound regions, we change the
1987 /// type from `Binder<T>` to just `T` (see
1988 /// e.g. `liberate_late_bound_regions`).
1989 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
1990 pub struct Binder<T>(pub T);
1993 /// Skips the binder and returns the "bound" value. This is a
1994 /// risky thing to do because it's easy to get confused about
1995 /// debruijn indices and the like. It is usually better to
1996 /// discharge the binder using `no_late_bound_regions` or
1997 /// `replace_late_bound_regions` or something like
1998 /// that. `skip_binder` is only valid when you are either
1999 /// extracting data that has nothing to do with bound regions, you
2000 /// are doing some sort of test that does not involve bound
2001 /// regions, or you are being very careful about your depth
2004 /// Some examples where `skip_binder` is reasonable:
2005 /// - extracting the def-id from a PolyTraitRef;
2006 /// - comparing the self type of a PolyTraitRef to see if it is equal to
2007 /// a type parameter `X`, since the type `X` does not reference any regions
2008 pub fn skip_binder(&self) -> &T {
2012 pub fn as_ref(&self) -> Binder<&T> {
2016 pub fn map_bound_ref<F,U>(&self, f: F) -> Binder<U>
2017 where F: FnOnce(&T) -> U
2019 self.as_ref().map_bound(f)
2022 pub fn map_bound<F,U>(self, f: F) -> Binder<U>
2023 where F: FnOnce(T) -> U
2025 ty::Binder(f(self.0))
2029 #[derive(Clone, Copy, PartialEq)]
2030 pub enum IntVarValue {
2031 IntType(ast::IntTy),
2032 UintType(ast::UintTy),
2035 #[derive(Clone, Copy, Debug)]
2036 pub struct ExpectedFound<T> {
2041 // Data structures used in type unification
2042 #[derive(Clone, Copy, Debug)]
2043 pub enum TypeError<'tcx> {
2045 UnsafetyMismatch(ExpectedFound<ast::Unsafety>),
2046 AbiMismatch(ExpectedFound<abi::Abi>),
2052 TupleSize(ExpectedFound<usize>),
2053 FixedArraySize(ExpectedFound<usize>),
2054 TyParamSize(ExpectedFound<usize>),
2056 RegionsDoesNotOutlive(Region, Region),
2057 RegionsNotSame(Region, Region),
2058 RegionsNoOverlap(Region, Region),
2059 RegionsInsufficientlyPolymorphic(BoundRegion, Region),
2060 RegionsOverlyPolymorphic(BoundRegion, Region),
2061 Sorts(ExpectedFound<Ty<'tcx>>),
2063 IntMismatch(ExpectedFound<IntVarValue>),
2064 FloatMismatch(ExpectedFound<ast::FloatTy>),
2065 Traits(ExpectedFound<ast::DefId>),
2066 BuiltinBoundsMismatch(ExpectedFound<BuiltinBounds>),
2067 VariadicMismatch(ExpectedFound<bool>),
2069 ConvergenceMismatch(ExpectedFound<bool>),
2070 ProjectionNameMismatched(ExpectedFound<ast::Name>),
2071 ProjectionBoundsLength(ExpectedFound<usize>),
2072 TyParamDefaultMismatch(ExpectedFound<Ty<'tcx>>)
2075 /// Bounds suitable for an existentially quantified type parameter
2076 /// such as those that appear in object types or closure types.
2077 #[derive(PartialEq, Eq, Hash, Clone)]
2078 pub struct ExistentialBounds<'tcx> {
2079 pub region_bound: ty::Region,
2080 pub builtin_bounds: BuiltinBounds,
2081 pub projection_bounds: Vec<PolyProjectionPredicate<'tcx>>,
2084 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
2085 pub struct BuiltinBounds(EnumSet<BuiltinBound>);
2087 impl BuiltinBounds {
2088 pub fn empty() -> BuiltinBounds {
2089 BuiltinBounds(EnumSet::new())
2092 pub fn iter(&self) -> enum_set::Iter<BuiltinBound> {
2096 pub fn to_predicates<'tcx>(&self,
2097 tcx: &ty::ctxt<'tcx>,
2098 self_ty: Ty<'tcx>) -> Vec<Predicate<'tcx>> {
2099 self.iter().filter_map(|builtin_bound|
2100 match traits::trait_ref_for_builtin_bound(tcx, builtin_bound, self_ty) {
2101 Ok(trait_ref) => Some(trait_ref.to_predicate()),
2102 Err(ErrorReported) => { None }
2108 impl ops::Deref for BuiltinBounds {
2109 type Target = EnumSet<BuiltinBound>;
2110 fn deref(&self) -> &Self::Target { &self.0 }
2113 impl ops::DerefMut for BuiltinBounds {
2114 fn deref_mut(&mut self) -> &mut Self::Target { &mut self.0 }
2117 impl<'a> IntoIterator for &'a BuiltinBounds {
2118 type Item = BuiltinBound;
2119 type IntoIter = enum_set::Iter<BuiltinBound>;
2120 fn into_iter(self) -> Self::IntoIter {
2121 (**self).into_iter()
2125 #[derive(Clone, RustcEncodable, PartialEq, Eq, RustcDecodable, Hash,
2128 pub enum BuiltinBound {
2135 impl CLike for BuiltinBound {
2136 fn to_usize(&self) -> usize {
2139 fn from_usize(v: usize) -> BuiltinBound {
2140 unsafe { mem::transmute(v) }
2144 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2149 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2154 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2155 pub struct FloatVid {
2159 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
2160 pub struct RegionVid {
2164 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2170 /// A `FreshTy` is one that is generated as a replacement for an
2171 /// unbound type variable. This is convenient for caching etc. See
2172 /// `middle::infer::freshen` for more details.
2178 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
2179 pub enum UnconstrainedNumeric {
2186 #[derive(Clone, RustcEncodable, RustcDecodable, Eq, Hash, Debug, Copy)]
2187 pub enum InferRegion {
2189 ReSkolemized(u32, BoundRegion)
2192 impl cmp::PartialEq for InferRegion {
2193 fn eq(&self, other: &InferRegion) -> bool {
2194 match ((*self), *other) {
2195 (ReVar(rva), ReVar(rvb)) => {
2198 (ReSkolemized(rva, _), ReSkolemized(rvb, _)) => {
2204 fn ne(&self, other: &InferRegion) -> bool {
2205 !((*self) == (*other))
2209 impl fmt::Debug for TyVid {
2210 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2211 write!(f, "_#{}t", self.index)
2215 impl fmt::Debug for IntVid {
2216 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2217 write!(f, "_#{}i", self.index)
2221 impl fmt::Debug for FloatVid {
2222 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2223 write!(f, "_#{}f", self.index)
2227 impl fmt::Debug for RegionVid {
2228 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2229 write!(f, "'_#{}r", self.index)
2233 impl<'tcx> fmt::Debug for FnSig<'tcx> {
2234 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2235 write!(f, "({:?}; variadic: {})->{:?}", self.inputs, self.variadic, self.output)
2239 impl fmt::Debug for InferTy {
2240 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2242 TyVar(ref v) => v.fmt(f),
2243 IntVar(ref v) => v.fmt(f),
2244 FloatVar(ref v) => v.fmt(f),
2245 FreshTy(v) => write!(f, "FreshTy({:?})", v),
2246 FreshIntTy(v) => write!(f, "FreshIntTy({:?})", v),
2247 FreshFloatTy(v) => write!(f, "FreshFloatTy({:?})", v)
2252 impl fmt::Debug for IntVarValue {
2253 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2255 IntType(ref v) => v.fmt(f),
2256 UintType(ref v) => v.fmt(f),
2261 /// Default region to use for the bound of objects that are
2262 /// supplied as the value for this type parameter. This is derived
2263 /// from `T:'a` annotations appearing in the type definition. If
2264 /// this is `None`, then the default is inherited from the
2265 /// surrounding context. See RFC #599 for details.
2266 #[derive(Copy, Clone)]
2267 pub enum ObjectLifetimeDefault {
2268 /// Require an explicit annotation. Occurs when multiple
2269 /// `T:'a` constraints are found.
2272 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
2275 /// Use the given region as the default.
2280 pub struct TypeParameterDef<'tcx> {
2281 pub name: ast::Name,
2282 pub def_id: ast::DefId,
2283 pub space: subst::ParamSpace,
2285 pub default: Option<Ty<'tcx>>,
2286 pub object_lifetime_default: ObjectLifetimeDefault,
2289 #[derive(RustcEncodable, RustcDecodable, Clone, Debug)]
2290 pub struct RegionParameterDef {
2291 pub name: ast::Name,
2292 pub def_id: ast::DefId,
2293 pub space: subst::ParamSpace,
2295 pub bounds: Vec<ty::Region>,
2298 impl RegionParameterDef {
2299 pub fn to_early_bound_region(&self) -> ty::Region {
2300 ty::ReEarlyBound(ty::EarlyBoundRegion {
2301 param_id: self.def_id.node,
2307 pub fn to_bound_region(&self) -> ty::BoundRegion {
2308 ty::BoundRegion::BrNamed(self.def_id, self.name)
2312 /// Information about the formal type/lifetime parameters associated
2313 /// with an item or method. Analogous to ast::Generics.
2314 #[derive(Clone, Debug)]
2315 pub struct Generics<'tcx> {
2316 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
2317 pub regions: VecPerParamSpace<RegionParameterDef>,
2320 impl<'tcx> Generics<'tcx> {
2321 pub fn empty() -> Generics<'tcx> {
2323 types: VecPerParamSpace::empty(),
2324 regions: VecPerParamSpace::empty(),
2328 pub fn is_empty(&self) -> bool {
2329 self.types.is_empty() && self.regions.is_empty()
2332 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
2333 !self.types.is_empty_in(space)
2336 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
2337 !self.regions.is_empty_in(space)
2341 /// Bounds on generics.
2343 pub struct GenericPredicates<'tcx> {
2344 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
2347 impl<'tcx> GenericPredicates<'tcx> {
2348 pub fn empty() -> GenericPredicates<'tcx> {
2350 predicates: VecPerParamSpace::empty(),
2354 pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
2355 -> InstantiatedPredicates<'tcx> {
2356 InstantiatedPredicates {
2357 predicates: self.predicates.subst(tcx, substs),
2361 pub fn instantiate_supertrait(&self,
2363 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
2364 -> InstantiatedPredicates<'tcx>
2366 InstantiatedPredicates {
2367 predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
2372 #[derive(Clone, PartialEq, Eq, Hash)]
2373 pub enum Predicate<'tcx> {
2374 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
2375 /// the `Self` type of the trait reference and `A`, `B`, and `C`
2376 /// would be the parameters in the `TypeSpace`.
2377 Trait(PolyTraitPredicate<'tcx>),
2379 /// where `T1 == T2`.
2380 Equate(PolyEquatePredicate<'tcx>),
2383 RegionOutlives(PolyRegionOutlivesPredicate),
2386 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
2388 /// where <T as TraitRef>::Name == X, approximately.
2389 /// See `ProjectionPredicate` struct for details.
2390 Projection(PolyProjectionPredicate<'tcx>),
2393 impl<'tcx> Predicate<'tcx> {
2394 /// Performs a substitution suitable for going from a
2395 /// poly-trait-ref to supertraits that must hold if that
2396 /// poly-trait-ref holds. This is slightly different from a normal
2397 /// substitution in terms of what happens with bound regions. See
2398 /// lengthy comment below for details.
2399 pub fn subst_supertrait(&self,
2401 trait_ref: &ty::PolyTraitRef<'tcx>)
2402 -> ty::Predicate<'tcx>
2404 // The interaction between HRTB and supertraits is not entirely
2405 // obvious. Let me walk you (and myself) through an example.
2407 // Let's start with an easy case. Consider two traits:
2409 // trait Foo<'a> : Bar<'a,'a> { }
2410 // trait Bar<'b,'c> { }
2412 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
2413 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
2414 // knew that `Foo<'x>` (for any 'x) then we also know that
2415 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
2416 // normal substitution.
2418 // In terms of why this is sound, the idea is that whenever there
2419 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
2420 // holds. So if there is an impl of `T:Foo<'a>` that applies to
2421 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
2424 // Another example to be careful of is this:
2426 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
2427 // trait Bar1<'b,'c> { }
2429 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
2430 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
2431 // reason is similar to the previous example: any impl of
2432 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
2433 // basically we would want to collapse the bound lifetimes from
2434 // the input (`trait_ref`) and the supertraits.
2436 // To achieve this in practice is fairly straightforward. Let's
2437 // consider the more complicated scenario:
2439 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
2440 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
2441 // where both `'x` and `'b` would have a DB index of 1.
2442 // The substitution from the input trait-ref is therefore going to be
2443 // `'a => 'x` (where `'x` has a DB index of 1).
2444 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
2445 // early-bound parameter and `'b' is a late-bound parameter with a
2447 // - If we replace `'a` with `'x` from the input, it too will have
2448 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
2449 // just as we wanted.
2451 // There is only one catch. If we just apply the substitution `'a
2452 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
2453 // adjust the DB index because we substituting into a binder (it
2454 // tries to be so smart...) resulting in `for<'x> for<'b>
2455 // Bar1<'x,'b>` (we have no syntax for this, so use your
2456 // imagination). Basically the 'x will have DB index of 2 and 'b
2457 // will have DB index of 1. Not quite what we want. So we apply
2458 // the substitution to the *contents* of the trait reference,
2459 // rather than the trait reference itself (put another way, the
2460 // substitution code expects equal binding levels in the values
2461 // from the substitution and the value being substituted into, and
2462 // this trick achieves that).
2464 let substs = &trait_ref.0.substs;
2466 Predicate::Trait(ty::Binder(ref data)) =>
2467 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
2468 Predicate::Equate(ty::Binder(ref data)) =>
2469 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
2470 Predicate::RegionOutlives(ty::Binder(ref data)) =>
2471 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
2472 Predicate::TypeOutlives(ty::Binder(ref data)) =>
2473 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
2474 Predicate::Projection(ty::Binder(ref data)) =>
2475 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
2480 #[derive(Clone, PartialEq, Eq, Hash)]
2481 pub struct TraitPredicate<'tcx> {
2482 pub trait_ref: TraitRef<'tcx>
2484 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
2486 impl<'tcx> TraitPredicate<'tcx> {
2487 pub fn def_id(&self) -> ast::DefId {
2488 self.trait_ref.def_id
2491 pub fn input_types(&self) -> &[Ty<'tcx>] {
2492 self.trait_ref.substs.types.as_slice()
2495 pub fn self_ty(&self) -> Ty<'tcx> {
2496 self.trait_ref.self_ty()
2500 impl<'tcx> PolyTraitPredicate<'tcx> {
2501 pub fn def_id(&self) -> ast::DefId {
2506 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
2507 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
2508 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
2510 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
2511 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
2512 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
2513 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
2514 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
2516 /// This kind of predicate has no *direct* correspondent in the
2517 /// syntax, but it roughly corresponds to the syntactic forms:
2519 /// 1. `T : TraitRef<..., Item=Type>`
2520 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
2522 /// In particular, form #1 is "desugared" to the combination of a
2523 /// normal trait predicate (`T : TraitRef<...>`) and one of these
2524 /// predicates. Form #2 is a broader form in that it also permits
2525 /// equality between arbitrary types. Processing an instance of Form
2526 /// #2 eventually yields one of these `ProjectionPredicate`
2527 /// instances to normalize the LHS.
2528 #[derive(Clone, PartialEq, Eq, Hash)]
2529 pub struct ProjectionPredicate<'tcx> {
2530 pub projection_ty: ProjectionTy<'tcx>,
2534 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
2536 impl<'tcx> PolyProjectionPredicate<'tcx> {
2537 pub fn item_name(&self) -> ast::Name {
2538 self.0.projection_ty.item_name // safe to skip the binder to access a name
2541 pub fn sort_key(&self) -> (ast::DefId, ast::Name) {
2542 self.0.projection_ty.sort_key()
2546 /// Represents the projection of an associated type. In explicit UFCS
2547 /// form this would be written `<T as Trait<..>>::N`.
2548 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
2549 pub struct ProjectionTy<'tcx> {
2550 /// The trait reference `T as Trait<..>`.
2551 pub trait_ref: ty::TraitRef<'tcx>,
2553 /// The name `N` of the associated type.
2554 pub item_name: ast::Name,
2557 impl<'tcx> ProjectionTy<'tcx> {
2558 pub fn sort_key(&self) -> (ast::DefId, ast::Name) {
2559 (self.trait_ref.def_id, self.item_name)
2563 pub trait ToPolyTraitRef<'tcx> {
2564 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
2567 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
2568 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
2569 assert!(!self.has_escaping_regions());
2570 ty::Binder(self.clone())
2574 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
2575 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
2576 self.map_bound_ref(|trait_pred| trait_pred.trait_ref.clone())
2580 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
2581 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
2582 // Note: unlike with TraitRef::to_poly_trait_ref(),
2583 // self.0.trait_ref is permitted to have escaping regions.
2584 // This is because here `self` has a `Binder` and so does our
2585 // return value, so we are preserving the number of binding
2587 ty::Binder(self.0.projection_ty.trait_ref.clone())
2591 pub trait ToPredicate<'tcx> {
2592 fn to_predicate(&self) -> Predicate<'tcx>;
2595 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
2596 fn to_predicate(&self) -> Predicate<'tcx> {
2597 // we're about to add a binder, so let's check that we don't
2598 // accidentally capture anything, or else that might be some
2599 // weird debruijn accounting.
2600 assert!(!self.has_escaping_regions());
2602 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
2603 trait_ref: self.clone()
2608 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
2609 fn to_predicate(&self) -> Predicate<'tcx> {
2610 ty::Predicate::Trait(self.to_poly_trait_predicate())
2614 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
2615 fn to_predicate(&self) -> Predicate<'tcx> {
2616 Predicate::Equate(self.clone())
2620 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
2621 fn to_predicate(&self) -> Predicate<'tcx> {
2622 Predicate::RegionOutlives(self.clone())
2626 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
2627 fn to_predicate(&self) -> Predicate<'tcx> {
2628 Predicate::TypeOutlives(self.clone())
2632 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
2633 fn to_predicate(&self) -> Predicate<'tcx> {
2634 Predicate::Projection(self.clone())
2638 impl<'tcx> Predicate<'tcx> {
2639 /// Iterates over the types in this predicate. Note that in all
2640 /// cases this is skipping over a binder, so late-bound regions
2641 /// with depth 0 are bound by the predicate.
2642 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
2643 let vec: Vec<_> = match *self {
2644 ty::Predicate::Trait(ref data) => {
2645 data.0.trait_ref.substs.types.as_slice().to_vec()
2647 ty::Predicate::Equate(ty::Binder(ref data)) => {
2648 vec![data.0, data.1]
2650 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
2653 ty::Predicate::RegionOutlives(..) => {
2656 ty::Predicate::Projection(ref data) => {
2657 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
2660 .chain(Some(data.0.ty))
2665 // The only reason to collect into a vector here is that I was
2666 // too lazy to make the full (somewhat complicated) iterator
2667 // type that would be needed here. But I wanted this fn to
2668 // return an iterator conceptually, rather than a `Vec`, so as
2669 // to be closer to `Ty::walk`.
2673 pub fn has_escaping_regions(&self) -> bool {
2675 Predicate::Trait(ref trait_ref) => trait_ref.has_escaping_regions(),
2676 Predicate::Equate(ref p) => p.has_escaping_regions(),
2677 Predicate::RegionOutlives(ref p) => p.has_escaping_regions(),
2678 Predicate::TypeOutlives(ref p) => p.has_escaping_regions(),
2679 Predicate::Projection(ref p) => p.has_escaping_regions(),
2683 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
2685 Predicate::Trait(ref t) => {
2686 Some(t.to_poly_trait_ref())
2688 Predicate::Projection(..) |
2689 Predicate::Equate(..) |
2690 Predicate::RegionOutlives(..) |
2691 Predicate::TypeOutlives(..) => {
2698 /// Represents the bounds declared on a particular set of type
2699 /// parameters. Should eventually be generalized into a flag list of
2700 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
2701 /// `GenericPredicates` by using the `instantiate` method. Note that this method
2702 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
2703 /// the `GenericPredicates` are expressed in terms of the bound type
2704 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
2705 /// represented a set of bounds for some particular instantiation,
2706 /// meaning that the generic parameters have been substituted with
2711 /// struct Foo<T,U:Bar<T>> { ... }
2713 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
2714 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
2715 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
2716 /// [usize:Bar<isize>]]`.
2718 pub struct InstantiatedPredicates<'tcx> {
2719 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
2722 impl<'tcx> InstantiatedPredicates<'tcx> {
2723 pub fn empty() -> InstantiatedPredicates<'tcx> {
2724 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
2727 pub fn has_escaping_regions(&self) -> bool {
2728 self.predicates.any(|p| p.has_escaping_regions())
2731 pub fn is_empty(&self) -> bool {
2732 self.predicates.is_empty()
2736 impl<'tcx> TraitRef<'tcx> {
2737 pub fn new(def_id: ast::DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
2738 TraitRef { def_id: def_id, substs: substs }
2741 pub fn self_ty(&self) -> Ty<'tcx> {
2742 self.substs.self_ty().unwrap()
2745 pub fn input_types(&self) -> &[Ty<'tcx>] {
2746 // Select only the "input types" from a trait-reference. For
2747 // now this is all the types that appear in the
2748 // trait-reference, but it should eventually exclude
2749 // associated types.
2750 self.substs.types.as_slice()
2754 /// When type checking, we use the `ParameterEnvironment` to track
2755 /// details about the type/lifetime parameters that are in scope.
2756 /// It primarily stores the bounds information.
2758 /// Note: This information might seem to be redundant with the data in
2759 /// `tcx.ty_param_defs`, but it is not. That table contains the
2760 /// parameter definitions from an "outside" perspective, but this
2761 /// struct will contain the bounds for a parameter as seen from inside
2762 /// the function body. Currently the only real distinction is that
2763 /// bound lifetime parameters are replaced with free ones, but in the
2764 /// future I hope to refine the representation of types so as to make
2765 /// more distinctions clearer.
2767 pub struct ParameterEnvironment<'a, 'tcx:'a> {
2768 pub tcx: &'a ctxt<'tcx>,
2770 /// See `construct_free_substs` for details.
2771 pub free_substs: Substs<'tcx>,
2773 /// Each type parameter has an implicit region bound that
2774 /// indicates it must outlive at least the function body (the user
2775 /// may specify stronger requirements). This field indicates the
2776 /// region of the callee.
2777 pub implicit_region_bound: ty::Region,
2779 /// Obligations that the caller must satisfy. This is basically
2780 /// the set of bounds on the in-scope type parameters, translated
2781 /// into Obligations, and elaborated and normalized.
2782 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
2784 /// Caches the results of trait selection. This cache is used
2785 /// for things that have to do with the parameters in scope.
2786 pub selection_cache: traits::SelectionCache<'tcx>,
2789 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
2790 pub fn with_caller_bounds(&self,
2791 caller_bounds: Vec<ty::Predicate<'tcx>>)
2792 -> ParameterEnvironment<'a,'tcx>
2794 ParameterEnvironment {
2796 free_substs: self.free_substs.clone(),
2797 implicit_region_bound: self.implicit_region_bound,
2798 caller_bounds: caller_bounds,
2799 selection_cache: traits::SelectionCache::new(),
2803 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
2804 match cx.map.find(id) {
2805 Some(ast_map::NodeImplItem(ref impl_item)) => {
2806 match impl_item.node {
2807 ast::ConstImplItem(_, _) => {
2808 let def_id = ast_util::local_def(id);
2809 let scheme = cx.lookup_item_type(def_id);
2810 let predicates = cx.lookup_predicates(def_id);
2811 cx.construct_parameter_environment(impl_item.span,
2816 ast::MethodImplItem(_, ref body) => {
2817 let method_def_id = ast_util::local_def(id);
2818 match cx.impl_or_trait_item(method_def_id) {
2819 MethodTraitItem(ref method_ty) => {
2820 let method_generics = &method_ty.generics;
2821 let method_bounds = &method_ty.predicates;
2822 cx.construct_parameter_environment(
2830 .bug("ParameterEnvironment::for_item(): \
2831 got non-method item from impl method?!")
2835 ast::TypeImplItem(_) => {
2836 cx.sess.bug("ParameterEnvironment::for_item(): \
2837 can't create a parameter environment \
2838 for type impl items")
2840 ast::MacImplItem(_) => cx.sess.bug("unexpanded macro")
2843 Some(ast_map::NodeTraitItem(trait_item)) => {
2844 match trait_item.node {
2845 ast::ConstTraitItem(_, ref default) => {
2848 let def_id = ast_util::local_def(id);
2849 let scheme = cx.lookup_item_type(def_id);
2850 let predicates = cx.lookup_predicates(def_id);
2851 cx.construct_parameter_environment(trait_item.span,
2857 cx.sess.bug("ParameterEnvironment::from_item(): \
2858 can't create a parameter environment \
2859 for const trait items without defaults")
2863 ast::MethodTraitItem(_, None) => {
2864 cx.sess.span_bug(trait_item.span,
2865 "ParameterEnvironment::for_item():
2866 can't create a parameter \
2867 environment for required trait \
2870 ast::MethodTraitItem(_, Some(ref body)) => {
2871 let method_def_id = ast_util::local_def(id);
2872 match cx.impl_or_trait_item(method_def_id) {
2873 MethodTraitItem(ref method_ty) => {
2874 let method_generics = &method_ty.generics;
2875 let method_bounds = &method_ty.predicates;
2876 cx.construct_parameter_environment(
2884 .bug("ParameterEnvironment::for_item(): \
2885 got non-method item from provided \
2890 ast::TypeTraitItem(..) => {
2891 cx.sess.bug("ParameterEnvironment::from_item(): \
2892 can't create a parameter environment \
2893 for type trait items")
2897 Some(ast_map::NodeItem(item)) => {
2899 ast::ItemFn(_, _, _, _, _, ref body) => {
2900 // We assume this is a function.
2901 let fn_def_id = ast_util::local_def(id);
2902 let fn_scheme = cx.lookup_item_type(fn_def_id);
2903 let fn_predicates = cx.lookup_predicates(fn_def_id);
2905 cx.construct_parameter_environment(item.span,
2906 &fn_scheme.generics,
2911 ast::ItemStruct(..) |
2913 ast::ItemConst(..) |
2914 ast::ItemStatic(..) => {
2915 let def_id = ast_util::local_def(id);
2916 let scheme = cx.lookup_item_type(def_id);
2917 let predicates = cx.lookup_predicates(def_id);
2918 cx.construct_parameter_environment(item.span,
2924 cx.sess.span_bug(item.span,
2925 "ParameterEnvironment::from_item():
2926 can't create a parameter \
2927 environment for this kind of item")
2931 Some(ast_map::NodeExpr(..)) => {
2932 // This is a convenience to allow closures to work.
2933 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
2936 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
2937 `{}` is not an item",
2938 cx.map.node_to_string(id)))
2943 pub fn can_type_implement_copy(&self, self_type: Ty<'tcx>, span: Span)
2944 -> Result<(),CopyImplementationError> {
2947 // FIXME: (@jroesch) float this code up
2948 let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, Some(self.clone()), false);
2950 let did = match self_type.sty {
2951 ty::TyStruct(struct_did, substs) => {
2952 let fields = tcx.struct_fields(struct_did, substs);
2953 for field in &fields {
2954 if infcx.type_moves_by_default(field.mt.ty, span) {
2955 return Err(FieldDoesNotImplementCopy(field.name))
2960 ty::TyEnum(enum_did, substs) => {
2961 let enum_variants = tcx.enum_variants(enum_did);
2962 for variant in enum_variants.iter() {
2963 for variant_arg_type in &variant.args {
2964 let substd_arg_type =
2965 variant_arg_type.subst(tcx, substs);
2966 if infcx.type_moves_by_default(substd_arg_type, span) {
2967 return Err(VariantDoesNotImplementCopy(variant.name))
2973 _ => return Err(TypeIsStructural),
2976 if tcx.has_dtor(did) {
2977 return Err(TypeHasDestructor)
2984 #[derive(Copy, Clone)]
2985 pub enum CopyImplementationError {
2986 FieldDoesNotImplementCopy(ast::Name),
2987 VariantDoesNotImplementCopy(ast::Name),
2992 /// A "type scheme", in ML terminology, is a type combined with some
2993 /// set of generic types that the type is, well, generic over. In Rust
2994 /// terms, it is the "type" of a fn item or struct -- this type will
2995 /// include various generic parameters that must be substituted when
2996 /// the item/struct is referenced. That is called converting the type
2997 /// scheme to a monotype.
2999 /// - `generics`: the set of type parameters and their bounds
3000 /// - `ty`: the base types, which may reference the parameters defined
3003 /// Note that TypeSchemes are also sometimes called "polytypes" (and
3004 /// in fact this struct used to carry that name, so you may find some
3005 /// stray references in a comment or something). We try to reserve the
3006 /// "poly" prefix to refer to higher-ranked things, as in
3009 /// Note that each item also comes with predicates, see
3010 /// `lookup_predicates`.
3011 #[derive(Clone, Debug)]
3012 pub struct TypeScheme<'tcx> {
3013 pub generics: Generics<'tcx>,
3018 flags TraitFlags: u32 {
3019 const NO_TRAIT_FLAGS = 0,
3020 const HAS_DEFAULT_IMPL = 1 << 0,
3021 const IS_OBJECT_SAFE = 1 << 1,
3022 const OBJECT_SAFETY_VALID = 1 << 2,
3023 const IMPLS_VALID = 1 << 3,
3027 /// As `TypeScheme` but for a trait ref.
3028 pub struct TraitDef<'tcx> {
3029 pub unsafety: ast::Unsafety,
3031 /// If `true`, then this trait had the `#[rustc_paren_sugar]`
3032 /// attribute, indicating that it should be used with `Foo()`
3033 /// sugar. This is a temporary thing -- eventually any trait wil
3034 /// be usable with the sugar (or without it).
3035 pub paren_sugar: bool,
3037 /// Generic type definitions. Note that `Self` is listed in here
3038 /// as having a single bound, the trait itself (e.g., in the trait
3039 /// `Eq`, there is a single bound `Self : Eq`). This is so that
3040 /// default methods get to assume that the `Self` parameters
3041 /// implements the trait.
3042 pub generics: Generics<'tcx>,
3044 pub trait_ref: TraitRef<'tcx>,
3046 /// A list of the associated types defined in this trait. Useful
3047 /// for resolving `X::Foo` type markers.
3048 pub associated_type_names: Vec<ast::Name>,
3050 // Impls of this trait. To allow for quicker lookup, the impls are indexed
3051 // by a simplified version of their Self type: impls with a simplifiable
3052 // Self are stored in nonblanket_impls keyed by it, while all other impls
3053 // are stored in blanket_impls.
3055 /// Impls of the trait.
3056 pub nonblanket_impls: RefCell<
3057 FnvHashMap<fast_reject::SimplifiedType, Vec<DefId>>
3060 /// Blanket impls associated with the trait.
3061 pub blanket_impls: RefCell<Vec<DefId>>,
3064 pub flags: Cell<TraitFlags>
3067 impl<'tcx> TraitDef<'tcx> {
3068 // returns None if not yet calculated
3069 pub fn object_safety(&self) -> Option<bool> {
3070 if self.flags.get().intersects(TraitFlags::OBJECT_SAFETY_VALID) {
3071 Some(self.flags.get().intersects(TraitFlags::IS_OBJECT_SAFE))
3077 pub fn set_object_safety(&self, is_safe: bool) {
3078 assert!(self.object_safety().map(|cs| cs == is_safe).unwrap_or(true));
3080 self.flags.get() | if is_safe {
3081 TraitFlags::OBJECT_SAFETY_VALID | TraitFlags::IS_OBJECT_SAFE
3083 TraitFlags::OBJECT_SAFETY_VALID
3088 /// Records a trait-to-implementation mapping.
3089 pub fn record_impl(&self,
3092 impl_trait_ref: TraitRef<'tcx>) {
3093 debug!("TraitDef::record_impl for {:?}, from {:?}",
3094 self, impl_trait_ref);
3096 // We don't want to borrow_mut after we already populated all impls,
3097 // so check if an impl is present with an immutable borrow first.
3098 if let Some(sty) = fast_reject::simplify_type(tcx,
3099 impl_trait_ref.self_ty(), false) {
3100 if let Some(is) = self.nonblanket_impls.borrow().get(&sty) {
3101 if is.contains(&impl_def_id) {
3102 return // duplicate - skip
3106 self.nonblanket_impls.borrow_mut().entry(sty).or_insert(vec![]).push(impl_def_id)
3108 if self.blanket_impls.borrow().contains(&impl_def_id) {
3109 return // duplicate - skip
3111 self.blanket_impls.borrow_mut().push(impl_def_id)
3116 pub fn for_each_impl<F: FnMut(DefId)>(&self, tcx: &ctxt<'tcx>, mut f: F) {
3117 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
3119 for &impl_def_id in self.blanket_impls.borrow().iter() {
3123 for v in self.nonblanket_impls.borrow().values() {
3124 for &impl_def_id in v {
3130 pub fn for_each_relevant_impl<F: FnMut(DefId)>(&self,
3135 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
3137 for &impl_def_id in self.blanket_impls.borrow().iter() {
3141 if let Some(simp) = fast_reject::simplify_type(tcx, self_ty, false) {
3142 if let Some(impls) = self.nonblanket_impls.borrow().get(&simp) {
3143 for &impl_def_id in impls {
3146 return; // we don't need to process the other non-blanket impls
3150 for v in self.nonblanket_impls.borrow().values() {
3151 for &impl_def_id in v {
3159 /// Records the substitutions used to translate the polytype for an
3160 /// item into the monotype of an item reference.
3162 pub struct ItemSubsts<'tcx> {
3163 pub substs: Substs<'tcx>,
3166 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
3167 pub enum ClosureKind {
3168 // Warning: Ordering is significant here! The ordering is chosen
3169 // because the trait Fn is a subtrait of FnMut and so in turn, and
3170 // hence we order it so that Fn < FnMut < FnOnce.
3177 pub fn trait_did(&self, cx: &ctxt) -> ast::DefId {
3178 let result = match *self {
3179 FnClosureKind => cx.lang_items.require(FnTraitLangItem),
3180 FnMutClosureKind => {
3181 cx.lang_items.require(FnMutTraitLangItem)
3183 FnOnceClosureKind => {
3184 cx.lang_items.require(FnOnceTraitLangItem)
3188 Ok(trait_did) => trait_did,
3189 Err(err) => cx.sess.fatal(&err[..]),
3193 /// True if this a type that impls this closure kind
3194 /// must also implement `other`.
3195 pub fn extends(self, other: ty::ClosureKind) -> bool {
3196 match (self, other) {
3197 (FnClosureKind, FnClosureKind) => true,
3198 (FnClosureKind, FnMutClosureKind) => true,
3199 (FnClosureKind, FnOnceClosureKind) => true,
3200 (FnMutClosureKind, FnMutClosureKind) => true,
3201 (FnMutClosureKind, FnOnceClosureKind) => true,
3202 (FnOnceClosureKind, FnOnceClosureKind) => true,
3208 impl<'tcx> CommonTypes<'tcx> {
3209 fn new(arena: &'tcx TypedArena<TyS<'tcx>>,
3210 interner: &RefCell<FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>>)
3211 -> CommonTypes<'tcx>
3213 let mk = |sty| ctxt::intern_ty(arena, interner, sty);
3218 isize: mk(TyInt(ast::TyIs)),
3219 i8: mk(TyInt(ast::TyI8)),
3220 i16: mk(TyInt(ast::TyI16)),
3221 i32: mk(TyInt(ast::TyI32)),
3222 i64: mk(TyInt(ast::TyI64)),
3223 usize: mk(TyUint(ast::TyUs)),
3224 u8: mk(TyUint(ast::TyU8)),
3225 u16: mk(TyUint(ast::TyU16)),
3226 u32: mk(TyUint(ast::TyU32)),
3227 u64: mk(TyUint(ast::TyU64)),
3228 f32: mk(TyFloat(ast::TyF32)),
3229 f64: mk(TyFloat(ast::TyF64)),
3234 struct FlagComputation {
3237 // maximum depth of any bound region that we have seen thus far
3241 impl FlagComputation {
3242 fn new() -> FlagComputation {
3243 FlagComputation { flags: TypeFlags::empty(), depth: 0 }
3246 fn for_sty(st: &TypeVariants) -> FlagComputation {
3247 let mut result = FlagComputation::new();
3252 fn add_flags(&mut self, flags: TypeFlags) {
3253 self.flags = self.flags | (flags & TypeFlags::NOMINAL_FLAGS);
3256 fn add_depth(&mut self, depth: u32) {
3257 if depth > self.depth {
3262 /// Adds the flags/depth from a set of types that appear within the current type, but within a
3264 fn add_bound_computation(&mut self, computation: &FlagComputation) {
3265 self.add_flags(computation.flags);
3267 // The types that contributed to `computation` occurred within
3268 // a region binder, so subtract one from the region depth
3269 // within when adding the depth to `self`.
3270 let depth = computation.depth;
3272 self.add_depth(depth - 1);
3276 fn add_sty(&mut self, st: &TypeVariants) {
3286 // You might think that we could just return TyError for
3287 // any type containing TyError as a component, and get
3288 // rid of the TypeFlags::HAS_TY_ERR flag -- likewise for ty_bot (with
3289 // the exception of function types that return bot).
3290 // But doing so caused sporadic memory corruption, and
3291 // neither I (tjc) nor nmatsakis could figure out why,
3292 // so we're doing it this way.
3294 self.add_flags(TypeFlags::HAS_TY_ERR)
3297 &TyParam(ref p) => {
3298 self.add_flags(TypeFlags::HAS_LOCAL_NAMES);
3299 if p.space == subst::SelfSpace {
3300 self.add_flags(TypeFlags::HAS_SELF);
3302 self.add_flags(TypeFlags::HAS_PARAMS);
3306 &TyClosure(_, ref substs) => {
3307 self.add_flags(TypeFlags::HAS_TY_CLOSURE);
3308 self.add_flags(TypeFlags::HAS_LOCAL_NAMES);
3309 self.add_substs(&substs.func_substs);
3310 self.add_tys(&substs.upvar_tys);
3314 self.add_flags(TypeFlags::HAS_LOCAL_NAMES); // it might, right?
3315 self.add_flags(TypeFlags::HAS_TY_INFER)
3318 &TyEnum(_, substs) | &TyStruct(_, substs) => {
3319 self.add_substs(substs);
3322 &TyProjection(ref data) => {
3323 self.add_flags(TypeFlags::HAS_PROJECTION);
3324 self.add_projection_ty(data);
3327 &TyTrait(box TraitTy { ref principal, ref bounds }) => {
3328 let mut computation = FlagComputation::new();
3329 computation.add_substs(principal.0.substs);
3330 for projection_bound in &bounds.projection_bounds {
3331 let mut proj_computation = FlagComputation::new();
3332 proj_computation.add_projection_predicate(&projection_bound.0);
3333 self.add_bound_computation(&proj_computation);
3335 self.add_bound_computation(&computation);
3337 self.add_bounds(bounds);
3340 &TyBox(tt) | &TyArray(tt, _) | &TySlice(tt) => {
3344 &TyRawPtr(ref m) => {
3348 &TyRef(r, ref m) => {
3349 self.add_region(*r);
3353 &TyTuple(ref ts) => {
3354 self.add_tys(&ts[..]);
3357 &TyBareFn(_, ref f) => {
3358 self.add_fn_sig(&f.sig);
3363 fn add_ty(&mut self, ty: Ty) {
3364 self.add_flags(ty.flags.get());
3365 self.add_depth(ty.region_depth);
3368 fn add_tys(&mut self, tys: &[Ty]) {
3374 fn add_fn_sig(&mut self, fn_sig: &PolyFnSig) {
3375 let mut computation = FlagComputation::new();
3377 computation.add_tys(&fn_sig.0.inputs);
3379 if let ty::FnConverging(output) = fn_sig.0.output {
3380 computation.add_ty(output);
3383 self.add_bound_computation(&computation);
3386 fn add_region(&mut self, r: Region) {
3388 ty::ReInfer(_) => { self.add_flags(TypeFlags::HAS_RE_INFER); }
3389 ty::ReLateBound(debruijn, _) => { self.add_depth(debruijn.depth); }
3390 ty::ReEarlyBound(..) => { self.add_flags(TypeFlags::HAS_RE_EARLY_BOUND); }
3392 _ => { self.add_flags(TypeFlags::HAS_FREE_REGIONS); }
3396 self.add_flags(TypeFlags::HAS_LOCAL_NAMES);
3400 fn add_projection_predicate(&mut self, projection_predicate: &ProjectionPredicate) {
3401 self.add_projection_ty(&projection_predicate.projection_ty);
3402 self.add_ty(projection_predicate.ty);
3405 fn add_projection_ty(&mut self, projection_ty: &ProjectionTy) {
3406 self.add_substs(projection_ty.trait_ref.substs);
3409 fn add_substs(&mut self, substs: &Substs) {
3410 self.add_tys(substs.types.as_slice());
3411 match substs.regions {
3412 subst::ErasedRegions => {}
3413 subst::NonerasedRegions(ref regions) => {
3421 fn add_bounds(&mut self, bounds: &ExistentialBounds) {
3422 self.add_region(bounds.region_bound);
3426 impl<'tcx> ctxt<'tcx> {
3427 /// Create a type context and call the closure with a `&ty::ctxt` reference
3428 /// to the context. The closure enforces that the type context and any interned
3429 /// value (types, substs, etc.) can only be used while `ty::tls` has a valid
3430 /// reference to the context, to allow formatting values that need it.
3431 pub fn create_and_enter<F, R>(s: Session,
3432 arenas: &'tcx CtxtArenas<'tcx>,
3434 named_region_map: resolve_lifetime::NamedRegionMap,
3435 map: ast_map::Map<'tcx>,
3436 freevars: RefCell<FreevarMap>,
3437 region_maps: RegionMaps,
3438 lang_items: middle::lang_items::LanguageItems,
3439 stability: stability::Index<'tcx>,
3440 f: F) -> (Session, R)
3441 where F: FnOnce(&ctxt<'tcx>) -> R
3443 let interner = RefCell::new(FnvHashMap());
3444 let common_types = CommonTypes::new(&arenas.type_, &interner);
3449 substs_interner: RefCell::new(FnvHashMap()),
3450 bare_fn_interner: RefCell::new(FnvHashMap()),
3451 region_interner: RefCell::new(FnvHashMap()),
3452 stability_interner: RefCell::new(FnvHashMap()),
3453 types: common_types,
3454 named_region_map: named_region_map,
3455 region_maps: region_maps,
3456 free_region_maps: RefCell::new(FnvHashMap()),
3457 item_variance_map: RefCell::new(DefIdMap()),
3458 variance_computed: Cell::new(false),
3461 tables: RefCell::new(Tables::empty()),
3462 impl_trait_refs: RefCell::new(DefIdMap()),
3463 trait_defs: RefCell::new(DefIdMap()),
3464 predicates: RefCell::new(DefIdMap()),
3465 super_predicates: RefCell::new(DefIdMap()),
3466 fulfilled_predicates: RefCell::new(traits::FulfilledPredicates::new()),
3469 tcache: RefCell::new(DefIdMap()),
3470 rcache: RefCell::new(FnvHashMap()),
3471 tc_cache: RefCell::new(FnvHashMap()),
3472 ast_ty_to_ty_cache: RefCell::new(NodeMap()),
3473 enum_var_cache: RefCell::new(DefIdMap()),
3474 impl_or_trait_items: RefCell::new(DefIdMap()),
3475 trait_item_def_ids: RefCell::new(DefIdMap()),
3476 trait_items_cache: RefCell::new(DefIdMap()),
3477 ty_param_defs: RefCell::new(NodeMap()),
3478 normalized_cache: RefCell::new(FnvHashMap()),
3479 lang_items: lang_items,
3480 provided_method_sources: RefCell::new(DefIdMap()),
3481 struct_fields: RefCell::new(DefIdMap()),
3482 destructor_for_type: RefCell::new(DefIdMap()),
3483 destructors: RefCell::new(DefIdSet()),
3484 inherent_impls: RefCell::new(DefIdMap()),
3485 impl_items: RefCell::new(DefIdMap()),
3486 used_unsafe: RefCell::new(NodeSet()),
3487 used_mut_nodes: RefCell::new(NodeSet()),
3488 populated_external_types: RefCell::new(DefIdSet()),
3489 populated_external_primitive_impls: RefCell::new(DefIdSet()),
3490 extern_const_statics: RefCell::new(DefIdMap()),
3491 extern_const_variants: RefCell::new(DefIdMap()),
3492 extern_const_fns: RefCell::new(DefIdMap()),
3493 dependency_formats: RefCell::new(FnvHashMap()),
3494 node_lint_levels: RefCell::new(FnvHashMap()),
3495 transmute_restrictions: RefCell::new(Vec::new()),
3496 stability: RefCell::new(stability),
3497 selection_cache: traits::SelectionCache::new(),
3498 repr_hint_cache: RefCell::new(DefIdMap()),
3499 const_qualif_map: RefCell::new(NodeMap()),
3500 custom_coerce_unsized_kinds: RefCell::new(DefIdMap()),
3501 cast_kinds: RefCell::new(NodeMap()),
3505 // Type constructors
3507 pub fn mk_substs(&self, substs: Substs<'tcx>) -> &'tcx Substs<'tcx> {
3508 if let Some(substs) = self.substs_interner.borrow().get(&substs) {
3512 let substs = self.arenas.substs.alloc(substs);
3513 self.substs_interner.borrow_mut().insert(substs, substs);
3517 /// Create an unsafe fn ty based on a safe fn ty.
3518 pub fn safe_to_unsafe_fn_ty(&self, bare_fn: &BareFnTy<'tcx>) -> Ty<'tcx> {
3519 assert_eq!(bare_fn.unsafety, ast::Unsafety::Normal);
3520 let unsafe_fn_ty_a = self.mk_bare_fn(ty::BareFnTy {
3521 unsafety: ast::Unsafety::Unsafe,
3523 sig: bare_fn.sig.clone()
3525 self.mk_fn(None, unsafe_fn_ty_a)
3528 pub fn mk_bare_fn(&self, bare_fn: BareFnTy<'tcx>) -> &'tcx BareFnTy<'tcx> {
3529 if let Some(bare_fn) = self.bare_fn_interner.borrow().get(&bare_fn) {
3533 let bare_fn = self.arenas.bare_fn.alloc(bare_fn);
3534 self.bare_fn_interner.borrow_mut().insert(bare_fn, bare_fn);
3538 pub fn mk_region(&self, region: Region) -> &'tcx Region {
3539 if let Some(region) = self.region_interner.borrow().get(®ion) {
3543 let region = self.arenas.region.alloc(region);
3544 self.region_interner.borrow_mut().insert(region, region);
3548 pub fn closure_kind(&self, def_id: ast::DefId) -> ty::ClosureKind {
3549 *self.tables.borrow().closure_kinds.get(&def_id).unwrap()
3552 pub fn closure_type(&self,
3554 substs: &ClosureSubsts<'tcx>)
3555 -> ty::ClosureTy<'tcx>
3557 self.tables.borrow().closure_tys.get(&def_id).unwrap().subst(self, &substs.func_substs)
3560 pub fn type_parameter_def(&self,
3561 node_id: ast::NodeId)
3562 -> TypeParameterDef<'tcx>
3564 self.ty_param_defs.borrow().get(&node_id).unwrap().clone()
3567 pub fn pat_contains_ref_binding(&self, pat: &ast::Pat) -> Option<ast::Mutability> {
3568 pat_util::pat_contains_ref_binding(&self.def_map, pat)
3571 pub fn arm_contains_ref_binding(&self, arm: &ast::Arm) -> Option<ast::Mutability> {
3572 pat_util::arm_contains_ref_binding(&self.def_map, arm)
3575 fn intern_ty(type_arena: &'tcx TypedArena<TyS<'tcx>>,
3576 interner: &RefCell<FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>>,
3577 st: TypeVariants<'tcx>)
3579 let ty: Ty /* don't be &mut TyS */ = {
3580 let mut interner = interner.borrow_mut();
3581 match interner.get(&st) {
3582 Some(ty) => return *ty,
3586 let flags = FlagComputation::for_sty(&st);
3589 () => type_arena.alloc(TyS { sty: st,
3590 flags: Cell::new(flags.flags),
3591 region_depth: flags.depth, }),
3594 interner.insert(InternedTy { ty: ty }, ty);
3598 debug!("Interned type: {:?} Pointer: {:?}",
3599 ty, ty as *const TyS);
3603 // Interns a type/name combination, stores the resulting box in cx.interner,
3604 // and returns the box as cast to an unsafe ptr (see comments for Ty above).
3605 pub fn mk_ty(&self, st: TypeVariants<'tcx>) -> Ty<'tcx> {
3606 ctxt::intern_ty(&self.arenas.type_, &self.interner, st)
3609 pub fn mk_mach_int(&self, tm: ast::IntTy) -> Ty<'tcx> {
3611 ast::TyIs => self.types.isize,
3612 ast::TyI8 => self.types.i8,
3613 ast::TyI16 => self.types.i16,
3614 ast::TyI32 => self.types.i32,
3615 ast::TyI64 => self.types.i64,
3619 pub fn mk_mach_uint(&self, tm: ast::UintTy) -> Ty<'tcx> {
3621 ast::TyUs => self.types.usize,
3622 ast::TyU8 => self.types.u8,
3623 ast::TyU16 => self.types.u16,
3624 ast::TyU32 => self.types.u32,
3625 ast::TyU64 => self.types.u64,
3629 pub fn mk_mach_float(&self, tm: ast::FloatTy) -> Ty<'tcx> {
3631 ast::TyF32 => self.types.f32,
3632 ast::TyF64 => self.types.f64,
3636 pub fn mk_str(&self) -> Ty<'tcx> {
3640 pub fn mk_static_str(&self) -> Ty<'tcx> {
3641 self.mk_imm_ref(self.mk_region(ty::ReStatic), self.mk_str())
3644 pub fn mk_enum(&self, did: ast::DefId, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
3645 // take a copy of substs so that we own the vectors inside
3646 self.mk_ty(TyEnum(did, substs))
3649 pub fn mk_box(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3650 self.mk_ty(TyBox(ty))
3653 pub fn mk_ptr(&self, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
3654 self.mk_ty(TyRawPtr(tm))
3657 pub fn mk_ref(&self, r: &'tcx Region, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
3658 self.mk_ty(TyRef(r, tm))
3661 pub fn mk_mut_ref(&self, r: &'tcx Region, ty: Ty<'tcx>) -> Ty<'tcx> {
3662 self.mk_ref(r, TypeAndMut {ty: ty, mutbl: ast::MutMutable})
3665 pub fn mk_imm_ref(&self, r: &'tcx Region, ty: Ty<'tcx>) -> Ty<'tcx> {
3666 self.mk_ref(r, TypeAndMut {ty: ty, mutbl: ast::MutImmutable})
3669 pub fn mk_mut_ptr(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3670 self.mk_ptr(TypeAndMut {ty: ty, mutbl: ast::MutMutable})
3673 pub fn mk_imm_ptr(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3674 self.mk_ptr(TypeAndMut {ty: ty, mutbl: ast::MutImmutable})
3677 pub fn mk_nil_ptr(&self) -> Ty<'tcx> {
3678 self.mk_imm_ptr(self.mk_nil())
3681 pub fn mk_array(&self, ty: Ty<'tcx>, n: usize) -> Ty<'tcx> {
3682 self.mk_ty(TyArray(ty, n))
3685 pub fn mk_slice(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3686 self.mk_ty(TySlice(ty))
3689 pub fn mk_tup(&self, ts: Vec<Ty<'tcx>>) -> Ty<'tcx> {
3690 self.mk_ty(TyTuple(ts))
3693 pub fn mk_nil(&self) -> Ty<'tcx> {
3694 self.mk_tup(Vec::new())
3697 pub fn mk_bool(&self) -> Ty<'tcx> {
3702 opt_def_id: Option<ast::DefId>,
3703 fty: &'tcx BareFnTy<'tcx>) -> Ty<'tcx> {
3704 self.mk_ty(TyBareFn(opt_def_id, fty))
3707 pub fn mk_ctor_fn(&self,
3709 input_tys: &[Ty<'tcx>],
3710 output: Ty<'tcx>) -> Ty<'tcx> {
3711 let input_args = input_tys.iter().cloned().collect();
3712 self.mk_fn(Some(def_id), self.mk_bare_fn(BareFnTy {
3713 unsafety: ast::Unsafety::Normal,
3715 sig: ty::Binder(FnSig {
3717 output: ty::FnConverging(output),
3723 pub fn mk_trait(&self,
3724 principal: ty::PolyTraitRef<'tcx>,
3725 bounds: ExistentialBounds<'tcx>)
3728 assert!(bound_list_is_sorted(&bounds.projection_bounds));
3730 let inner = box TraitTy {
3731 principal: principal,
3734 self.mk_ty(TyTrait(inner))
3737 pub fn mk_projection(&self,
3738 trait_ref: TraitRef<'tcx>,
3739 item_name: ast::Name)
3741 // take a copy of substs so that we own the vectors inside
3742 let inner = ProjectionTy { trait_ref: trait_ref, item_name: item_name };
3743 self.mk_ty(TyProjection(inner))
3746 pub fn mk_struct(&self, struct_id: ast::DefId,
3747 substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
3748 // take a copy of substs so that we own the vectors inside
3749 self.mk_ty(TyStruct(struct_id, substs))
3752 pub fn mk_closure(&self,
3753 closure_id: ast::DefId,
3754 substs: &'tcx Substs<'tcx>,
3757 self.mk_closure_from_closure_substs(closure_id, Box::new(ClosureSubsts {
3758 func_substs: substs,
3763 pub fn mk_closure_from_closure_substs(&self,
3764 closure_id: ast::DefId,
3765 closure_substs: Box<ClosureSubsts<'tcx>>)
3767 self.mk_ty(TyClosure(closure_id, closure_substs))
3770 pub fn mk_var(&self, v: TyVid) -> Ty<'tcx> {
3771 self.mk_infer(TyVar(v))
3774 pub fn mk_int_var(&self, v: IntVid) -> Ty<'tcx> {
3775 self.mk_infer(IntVar(v))
3778 pub fn mk_float_var(&self, v: FloatVid) -> Ty<'tcx> {
3779 self.mk_infer(FloatVar(v))
3782 pub fn mk_infer(&self, it: InferTy) -> Ty<'tcx> {
3783 self.mk_ty(TyInfer(it))
3786 pub fn mk_param(&self,
3787 space: subst::ParamSpace,
3789 name: ast::Name) -> Ty<'tcx> {
3790 self.mk_ty(TyParam(ParamTy { space: space, idx: index, name: name }))
3793 pub fn mk_self_type(&self) -> Ty<'tcx> {
3794 self.mk_param(subst::SelfSpace, 0, special_idents::type_self.name)
3797 pub fn mk_param_from_def(&self, def: &TypeParameterDef) -> Ty<'tcx> {
3798 self.mk_param(def.space, def.index, def.name)
3802 fn bound_list_is_sorted(bounds: &[ty::PolyProjectionPredicate]) -> bool {
3803 bounds.is_empty() ||
3804 bounds[1..].iter().enumerate().all(
3805 |(index, bound)| bounds[index].sort_key() <= bound.sort_key())
3808 pub fn sort_bounds_list(bounds: &mut [ty::PolyProjectionPredicate]) {
3809 bounds.sort_by(|a, b| a.sort_key().cmp(&b.sort_key()))
3812 impl<'tcx> TyS<'tcx> {
3813 /// Iterator that walks `self` and any types reachable from
3814 /// `self`, in depth-first order. Note that just walks the types
3815 /// that appear in `self`, it does not descend into the fields of
3816 /// structs or variants. For example:
3819 /// isize => { isize }
3820 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
3821 /// [isize] => { [isize], isize }
3823 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
3824 TypeWalker::new(self)
3827 /// Iterator that walks the immediate children of `self`. Hence
3828 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
3829 /// (but not `i32`, like `walk`).
3830 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
3831 ty_walk::walk_shallow(self)
3834 pub fn as_opt_param_ty(&self) -> Option<ty::ParamTy> {
3836 ty::TyParam(ref d) => Some(d.clone()),
3841 pub fn is_param(&self, space: ParamSpace, index: u32) -> bool {
3843 ty::TyParam(ref data) => data.space == space && data.idx == index,
3848 /// Walks `ty` and any types appearing within `ty`, invoking the
3849 /// callback `f` on each type. If the callback returns false, then the
3850 /// children of the current type are ignored.
3852 /// Note: prefer `ty.walk()` where possible.
3853 pub fn maybe_walk<F>(&'tcx self, mut f: F)
3854 where F : FnMut(Ty<'tcx>) -> bool
3856 let mut walker = self.walk();
3857 while let Some(ty) = walker.next() {
3859 walker.skip_current_subtree();
3866 pub fn new(space: subst::ParamSpace,
3870 ParamTy { space: space, idx: index, name: name }
3873 pub fn for_self() -> ParamTy {
3874 ParamTy::new(subst::SelfSpace, 0, special_idents::type_self.name)
3877 pub fn for_def(def: &TypeParameterDef) -> ParamTy {
3878 ParamTy::new(def.space, def.index, def.name)
3881 pub fn to_ty<'tcx>(self, tcx: &ctxt<'tcx>) -> Ty<'tcx> {
3882 tcx.mk_param(self.space, self.idx, self.name)
3885 pub fn is_self(&self) -> bool {
3886 self.space == subst::SelfSpace && self.idx == 0
3890 impl<'tcx> ItemSubsts<'tcx> {
3891 pub fn empty() -> ItemSubsts<'tcx> {
3892 ItemSubsts { substs: Substs::empty() }
3895 pub fn is_noop(&self) -> bool {
3896 self.substs.is_noop()
3901 impl<'tcx> TyS<'tcx> {
3902 pub fn is_nil(&self) -> bool {
3904 TyTuple(ref tys) => tys.is_empty(),
3909 pub fn is_empty(&self, cx: &ctxt) -> bool {
3911 TyEnum(did, _) => cx.enum_variants(did).is_empty(),
3916 pub fn is_ty_var(&self) -> bool {
3918 TyInfer(TyVar(_)) => true,
3923 pub fn is_bool(&self) -> bool { self.sty == TyBool }
3925 pub fn is_self(&self) -> bool {
3927 TyParam(ref p) => p.space == subst::SelfSpace,
3932 fn is_slice(&self) -> bool {
3934 TyRawPtr(mt) | TyRef(_, mt) => match mt.ty.sty {
3935 TySlice(_) | TyStr => true,
3942 pub fn is_structural(&self) -> bool {
3944 TyStruct(..) | TyTuple(_) | TyEnum(..) |
3945 TyArray(..) | TyClosure(..) => true,
3946 _ => self.is_slice() | self.is_trait()
3950 pub fn is_simd(&self, cx: &ctxt) -> bool {
3952 TyStruct(did, _) => cx.lookup_simd(did),
3957 pub fn sequence_element_type(&self, cx: &ctxt<'tcx>) -> Ty<'tcx> {
3959 TyArray(ty, _) | TySlice(ty) => ty,
3960 TyStr => cx.mk_mach_uint(ast::TyU8),
3961 _ => cx.sess.bug(&format!("sequence_element_type called on non-sequence value: {}",
3966 pub fn simd_type(&self, cx: &ctxt<'tcx>) -> Ty<'tcx> {
3968 TyStruct(did, substs) => {
3969 let fields = cx.lookup_struct_fields(did);
3970 cx.lookup_field_type(did, fields[0].id, substs)
3972 _ => panic!("simd_type called on invalid type")
3976 pub fn simd_size(&self, cx: &ctxt) -> usize {
3978 TyStruct(did, _) => {
3979 cx.lookup_struct_fields(did).len()
3981 _ => panic!("simd_size called on invalid type")
3985 pub fn is_region_ptr(&self) -> bool {
3992 pub fn is_unsafe_ptr(&self) -> bool {
3994 TyRawPtr(_) => return true,
3999 pub fn is_unique(&self) -> bool {
4007 A scalar type is one that denotes an atomic datum, with no sub-components.
4008 (A TyRawPtr is scalar because it represents a non-managed pointer, so its
4009 contents are abstract to rustc.)
4011 pub fn is_scalar(&self) -> bool {
4013 TyBool | TyChar | TyInt(_) | TyFloat(_) | TyUint(_) |
4014 TyInfer(IntVar(_)) | TyInfer(FloatVar(_)) |
4015 TyBareFn(..) | TyRawPtr(_) => true,
4020 /// Returns true if this type is a floating point type and false otherwise.
4021 pub fn is_floating_point(&self) -> bool {
4024 TyInfer(FloatVar(_)) => true,
4029 pub fn ty_to_def_id(&self) -> Option<ast::DefId> {
4031 TyTrait(ref tt) => Some(tt.principal_def_id()),
4034 TyClosure(id, _) => Some(id),
4040 /// Type contents is how the type checker reasons about kinds.
4041 /// They track what kinds of things are found within a type. You can
4042 /// think of them as kind of an "anti-kind". They track the kinds of values
4043 /// and thinks that are contained in types. Having a larger contents for
4044 /// a type tends to rule that type *out* from various kinds. For example,
4045 /// a type that contains a reference is not sendable.
4047 /// The reason we compute type contents and not kinds is that it is
4048 /// easier for me (nmatsakis) to think about what is contained within
4049 /// a type than to think about what is *not* contained within a type.
4050 #[derive(Clone, Copy)]
4051 pub struct TypeContents {
4055 macro_rules! def_type_content_sets {
4056 (mod $mname:ident { $($name:ident = $bits:expr),+ }) => {
4057 #[allow(non_snake_case)]
4059 use middle::ty::TypeContents;
4061 #[allow(non_upper_case_globals)]
4062 pub const $name: TypeContents = TypeContents { bits: $bits };
4068 def_type_content_sets! {
4070 None = 0b0000_0000__0000_0000__0000,
4072 // Things that are interior to the value (first nibble):
4073 InteriorUnsafe = 0b0000_0000__0000_0000__0010,
4074 InteriorParam = 0b0000_0000__0000_0000__0100,
4075 // InteriorAll = 0b00000000__00000000__1111,
4077 // Things that are owned by the value (second and third nibbles):
4078 OwnsOwned = 0b0000_0000__0000_0001__0000,
4079 OwnsDtor = 0b0000_0000__0000_0010__0000,
4080 OwnsAll = 0b0000_0000__1111_1111__0000,
4082 // Things that mean drop glue is necessary
4083 NeedsDrop = 0b0000_0000__0000_0111__0000,
4086 All = 0b1111_1111__1111_1111__1111
4091 pub fn when(&self, cond: bool) -> TypeContents {
4092 if cond {*self} else {TC::None}
4095 pub fn intersects(&self, tc: TypeContents) -> bool {
4096 (self.bits & tc.bits) != 0
4099 pub fn owns_owned(&self) -> bool {
4100 self.intersects(TC::OwnsOwned)
4103 pub fn interior_param(&self) -> bool {
4104 self.intersects(TC::InteriorParam)
4107 pub fn interior_unsafe(&self) -> bool {
4108 self.intersects(TC::InteriorUnsafe)
4111 pub fn needs_drop(&self, _: &ctxt) -> bool {
4112 self.intersects(TC::NeedsDrop)
4115 /// Includes only those bits that still apply when indirected through a `Box` pointer
4116 pub fn owned_pointer(&self) -> TypeContents {
4117 TC::OwnsOwned | (*self & TC::OwnsAll)
4120 pub fn union<T, F>(v: &[T], mut f: F) -> TypeContents where
4121 F: FnMut(&T) -> TypeContents,
4123 v.iter().fold(TC::None, |tc, ty| tc | f(ty))
4126 pub fn has_dtor(&self) -> bool {
4127 self.intersects(TC::OwnsDtor)
4131 impl ops::BitOr for TypeContents {
4132 type Output = TypeContents;
4134 fn bitor(self, other: TypeContents) -> TypeContents {
4135 TypeContents {bits: self.bits | other.bits}
4139 impl ops::BitAnd for TypeContents {
4140 type Output = TypeContents;
4142 fn bitand(self, other: TypeContents) -> TypeContents {
4143 TypeContents {bits: self.bits & other.bits}
4147 impl ops::Sub for TypeContents {
4148 type Output = TypeContents;
4150 fn sub(self, other: TypeContents) -> TypeContents {
4151 TypeContents {bits: self.bits & !other.bits}
4155 impl fmt::Debug for TypeContents {
4156 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
4157 write!(f, "TypeContents({:b})", self.bits)
4161 impl<'tcx> TyS<'tcx> {
4162 pub fn type_contents(&'tcx self, cx: &ctxt<'tcx>) -> TypeContents {
4163 return memoized(&cx.tc_cache, self, |ty| {
4164 tc_ty(cx, ty, &mut FnvHashMap())
4167 fn tc_ty<'tcx>(cx: &ctxt<'tcx>,
4169 cache: &mut FnvHashMap<Ty<'tcx>, TypeContents>) -> TypeContents
4171 // Subtle: Note that we are *not* using cx.tc_cache here but rather a
4172 // private cache for this walk. This is needed in the case of cyclic
4175 // struct List { next: Box<Option<List>>, ... }
4177 // When computing the type contents of such a type, we wind up deeply
4178 // recursing as we go. So when we encounter the recursive reference
4179 // to List, we temporarily use TC::None as its contents. Later we'll
4180 // patch up the cache with the correct value, once we've computed it
4181 // (this is basically a co-inductive process, if that helps). So in
4182 // the end we'll compute TC::OwnsOwned, in this case.
4184 // The problem is, as we are doing the computation, we will also
4185 // compute an *intermediate* contents for, e.g., Option<List> of
4186 // TC::None. This is ok during the computation of List itself, but if
4187 // we stored this intermediate value into cx.tc_cache, then later
4188 // requests for the contents of Option<List> would also yield TC::None
4189 // which is incorrect. This value was computed based on the crutch
4190 // value for the type contents of list. The correct value is
4191 // TC::OwnsOwned. This manifested as issue #4821.
4192 match cache.get(&ty) {
4193 Some(tc) => { return *tc; }
4196 match cx.tc_cache.borrow().get(&ty) { // Must check both caches!
4197 Some(tc) => { return *tc; }
4200 cache.insert(ty, TC::None);
4202 let result = match ty.sty {
4203 // usize and isize are ffi-unsafe
4204 TyUint(ast::TyUs) | TyInt(ast::TyIs) => {
4208 // Scalar and unique types are sendable, and durable
4209 TyInfer(ty::FreshIntTy(_)) | TyInfer(ty::FreshFloatTy(_)) |
4210 TyBool | TyInt(_) | TyUint(_) | TyFloat(_) |
4211 TyBareFn(..) | ty::TyChar => {
4216 tc_ty(cx, typ, cache).owned_pointer()
4220 TC::All - TC::InteriorParam
4232 tc_ty(cx, ty, cache)
4236 tc_ty(cx, ty, cache)
4240 TyStruct(did, substs) => {
4241 let flds = cx.struct_fields(did, substs);
4243 TypeContents::union(&flds[..],
4244 |f| tc_ty(cx, f.mt.ty, cache));
4246 if cx.has_dtor(did) {
4247 res = res | TC::OwnsDtor;
4249 apply_lang_items(cx, did, res)
4252 TyClosure(_, ref substs) => {
4253 TypeContents::union(&substs.upvar_tys, |ty| tc_ty(cx, &ty, cache))
4256 TyTuple(ref tys) => {
4257 TypeContents::union(&tys[..],
4258 |ty| tc_ty(cx, *ty, cache))
4261 TyEnum(did, substs) => {
4262 let variants = cx.substd_enum_variants(did, substs);
4264 TypeContents::union(&variants[..], |variant| {
4265 TypeContents::union(&variant.args,
4267 tc_ty(cx, *arg_ty, cache)
4271 if cx.has_dtor(did) {
4272 res = res | TC::OwnsDtor;
4275 apply_lang_items(cx, did, res)
4285 cx.sess.bug("asked to compute contents of error type");
4289 cache.insert(ty, result);
4293 fn apply_lang_items(cx: &ctxt, did: ast::DefId, tc: TypeContents)
4295 if Some(did) == cx.lang_items.unsafe_cell_type() {
4296 tc | TC::InteriorUnsafe
4303 fn impls_bound<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4304 bound: ty::BuiltinBound,
4308 let tcx = param_env.tcx;
4309 let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, Some(param_env.clone()), false);
4311 let is_impld = traits::type_known_to_meet_builtin_bound(&infcx,
4314 debug!("Ty::impls_bound({:?}, {:?}) = {:?}",
4315 self, bound, is_impld);
4320 // FIXME (@jroesch): I made this public to use it, not sure if should be private
4321 pub fn moves_by_default<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4322 span: Span) -> bool {
4323 if self.flags.get().intersects(TypeFlags::MOVENESS_CACHED) {
4324 return self.flags.get().intersects(TypeFlags::MOVES_BY_DEFAULT);
4327 assert!(!self.needs_infer());
4329 // Fast-path for primitive types
4330 let result = match self.sty {
4331 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
4332 TyRawPtr(..) | TyBareFn(..) | TyRef(_, TypeAndMut {
4333 mutbl: ast::MutImmutable, ..
4336 TyStr | TyBox(..) | TyRef(_, TypeAndMut {
4337 mutbl: ast::MutMutable, ..
4340 TyArray(..) | TySlice(_) | TyTrait(..) | TyTuple(..) |
4341 TyClosure(..) | TyEnum(..) | TyStruct(..) |
4342 TyProjection(..) | TyParam(..) | TyInfer(..) | TyError => None
4343 }.unwrap_or_else(|| !self.impls_bound(param_env, ty::BoundCopy, span));
4345 if !self.has_param_types() && !self.has_self_ty() {
4346 self.flags.set(self.flags.get() | if result {
4347 TypeFlags::MOVENESS_CACHED | TypeFlags::MOVES_BY_DEFAULT
4349 TypeFlags::MOVENESS_CACHED
4357 pub fn is_sized<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4360 if self.flags.get().intersects(TypeFlags::SIZEDNESS_CACHED) {
4361 return self.flags.get().intersects(TypeFlags::IS_SIZED);
4364 self.is_sized_uncached(param_env, span)
4367 fn is_sized_uncached<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4368 span: Span) -> bool {
4369 assert!(!self.needs_infer());
4371 // Fast-path for primitive types
4372 let result = match self.sty {
4373 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
4374 TyBox(..) | TyRawPtr(..) | TyRef(..) | TyBareFn(..) |
4375 TyArray(..) | TyTuple(..) | TyClosure(..) => Some(true),
4377 TyStr | TyTrait(..) | TySlice(_) => Some(false),
4379 TyEnum(..) | TyStruct(..) | TyProjection(..) | TyParam(..) |
4380 TyInfer(..) | TyError => None
4381 }.unwrap_or_else(|| self.impls_bound(param_env, ty::BoundSized, span));
4383 if !self.has_param_types() && !self.has_self_ty() {
4384 self.flags.set(self.flags.get() | if result {
4385 TypeFlags::SIZEDNESS_CACHED | TypeFlags::IS_SIZED
4387 TypeFlags::SIZEDNESS_CACHED
4394 // True if instantiating an instance of `r_ty` requires an instance of `r_ty`.
4395 pub fn is_instantiable(&'tcx self, cx: &ctxt<'tcx>) -> bool {
4396 fn type_requires<'tcx>(cx: &ctxt<'tcx>, seen: &mut Vec<DefId>,
4397 r_ty: Ty<'tcx>, ty: Ty<'tcx>) -> bool {
4398 debug!("type_requires({:?}, {:?})?",
4401 let r = r_ty == ty || subtypes_require(cx, seen, r_ty, ty);
4403 debug!("type_requires({:?}, {:?})? {:?}",
4408 fn subtypes_require<'tcx>(cx: &ctxt<'tcx>, seen: &mut Vec<DefId>,
4409 r_ty: Ty<'tcx>, ty: Ty<'tcx>) -> bool {
4410 debug!("subtypes_require({:?}, {:?})?",
4413 let r = match ty.sty {
4414 // fixed length vectors need special treatment compared to
4415 // normal vectors, since they don't necessarily have the
4416 // possibility to have length zero.
4417 TyArray(_, 0) => false, // don't need no contents
4418 TyArray(ty, _) => type_requires(cx, seen, r_ty, ty),
4433 type_requires(cx, seen, r_ty, typ)
4435 TyRef(_, ref mt) => {
4436 type_requires(cx, seen, r_ty, mt.ty)
4440 false // unsafe ptrs can always be NULL
4447 TyStruct(ref did, _) if seen.contains(did) => {
4451 TyStruct(did, substs) => {
4453 let fields = cx.struct_fields(did, substs);
4454 let r = fields.iter().any(|f| type_requires(cx, seen, r_ty, f.mt.ty));
4455 seen.pop().unwrap();
4462 // this check is run on type definitions, so we don't expect to see
4463 // inference by-products or closure types
4464 cx.sess.bug(&format!("requires check invoked on inapplicable type: {:?}", ty))
4467 TyTuple(ref ts) => {
4468 ts.iter().any(|ty| type_requires(cx, seen, r_ty, *ty))
4471 TyEnum(ref did, _) if seen.contains(did) => {
4475 TyEnum(did, substs) => {
4477 let vs = cx.enum_variants(did);
4478 let r = !vs.is_empty() && vs.iter().all(|variant| {
4479 variant.args.iter().any(|aty| {
4480 let sty = aty.subst(cx, substs);
4481 type_requires(cx, seen, r_ty, sty)
4484 seen.pop().unwrap();
4489 debug!("subtypes_require({:?}, {:?})? {:?}",
4495 let mut seen = Vec::new();
4496 !subtypes_require(cx, &mut seen, self, self)
4500 /// Describes whether a type is representable. For types that are not
4501 /// representable, 'SelfRecursive' and 'ContainsRecursive' are used to
4502 /// distinguish between types that are recursive with themselves and types that
4503 /// contain a different recursive type. These cases can therefore be treated
4504 /// differently when reporting errors.
4506 /// The ordering of the cases is significant. They are sorted so that cmp::max
4507 /// will keep the "more erroneous" of two values.
4508 #[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
4509 pub enum Representability {
4515 impl<'tcx> TyS<'tcx> {
4516 /// Check whether a type is representable. This means it cannot contain unboxed
4517 /// structural recursion. This check is needed for structs and enums.
4518 pub fn is_representable(&'tcx self, cx: &ctxt<'tcx>, sp: Span) -> Representability {
4520 // Iterate until something non-representable is found
4521 fn find_nonrepresentable<'tcx, It: Iterator<Item=Ty<'tcx>>>(cx: &ctxt<'tcx>, sp: Span,
4522 seen: &mut Vec<Ty<'tcx>>,
4524 -> Representability {
4525 iter.fold(Representable,
4526 |r, ty| cmp::max(r, is_type_structurally_recursive(cx, sp, seen, ty)))
4529 fn are_inner_types_recursive<'tcx>(cx: &ctxt<'tcx>, sp: Span,
4530 seen: &mut Vec<Ty<'tcx>>, ty: Ty<'tcx>)
4531 -> Representability {
4533 TyTuple(ref ts) => {
4534 find_nonrepresentable(cx, sp, seen, ts.iter().cloned())
4536 // Fixed-length vectors.
4537 // FIXME(#11924) Behavior undecided for zero-length vectors.
4539 is_type_structurally_recursive(cx, sp, seen, ty)
4541 TyStruct(did, substs) => {
4542 let fields = cx.struct_fields(did, substs);
4543 find_nonrepresentable(cx, sp, seen, fields.iter().map(|f| f.mt.ty))
4545 TyEnum(did, substs) => {
4546 let vs = cx.enum_variants(did);
4547 let iter = vs.iter()
4548 .flat_map(|variant| &variant.args)
4549 .map(|aty| { aty.subst_spanned(cx, substs, Some(sp)) });
4551 find_nonrepresentable(cx, sp, seen, iter)
4554 // this check is run on type definitions, so we don't expect
4555 // to see closure types
4556 cx.sess.bug(&format!("requires check invoked on inapplicable type: {:?}", ty))
4562 fn same_struct_or_enum_def_id(ty: Ty, did: DefId) -> bool {
4564 TyStruct(ty_did, _) | TyEnum(ty_did, _) => {
4571 fn same_type<'tcx>(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
4572 match (&a.sty, &b.sty) {
4573 (&TyStruct(did_a, ref substs_a), &TyStruct(did_b, ref substs_b)) |
4574 (&TyEnum(did_a, ref substs_a), &TyEnum(did_b, ref substs_b)) => {
4579 let types_a = substs_a.types.get_slice(subst::TypeSpace);
4580 let types_b = substs_b.types.get_slice(subst::TypeSpace);
4582 let mut pairs = types_a.iter().zip(types_b);
4584 pairs.all(|(&a, &b)| same_type(a, b))
4592 // Does the type `ty` directly (without indirection through a pointer)
4593 // contain any types on stack `seen`?
4594 fn is_type_structurally_recursive<'tcx>(cx: &ctxt<'tcx>, sp: Span,
4595 seen: &mut Vec<Ty<'tcx>>,
4596 ty: Ty<'tcx>) -> Representability {
4597 debug!("is_type_structurally_recursive: {:?}", ty);
4600 TyStruct(did, _) | TyEnum(did, _) => {
4602 // Iterate through stack of previously seen types.
4603 let mut iter = seen.iter();
4605 // The first item in `seen` is the type we are actually curious about.
4606 // We want to return SelfRecursive if this type contains itself.
4607 // It is important that we DON'T take generic parameters into account
4608 // for this check, so that Bar<T> in this example counts as SelfRecursive:
4611 // struct Bar<T> { x: Bar<Foo> }
4614 Some(&seen_type) => {
4615 if same_struct_or_enum_def_id(seen_type, did) {
4616 debug!("SelfRecursive: {:?} contains {:?}",
4619 return SelfRecursive;
4625 // We also need to know whether the first item contains other types
4626 // that are structurally recursive. If we don't catch this case, we
4627 // will recurse infinitely for some inputs.
4629 // It is important that we DO take generic parameters into account
4630 // here, so that code like this is considered SelfRecursive, not
4631 // ContainsRecursive:
4633 // struct Foo { Option<Option<Foo>> }
4635 for &seen_type in iter {
4636 if same_type(ty, seen_type) {
4637 debug!("ContainsRecursive: {:?} contains {:?}",
4640 return ContainsRecursive;
4645 // For structs and enums, track all previously seen types by pushing them
4646 // onto the 'seen' stack.
4648 let out = are_inner_types_recursive(cx, sp, seen, ty);
4653 // No need to push in other cases.
4654 are_inner_types_recursive(cx, sp, seen, ty)
4659 debug!("is_type_representable: {:?}", self);
4661 // To avoid a stack overflow when checking an enum variant or struct that
4662 // contains a different, structurally recursive type, maintain a stack
4663 // of seen types and check recursion for each of them (issues #3008, #3779).
4664 let mut seen: Vec<Ty> = Vec::new();
4665 let r = is_type_structurally_recursive(cx, sp, &mut seen, self);
4666 debug!("is_type_representable: {:?} is {:?}", self, r);
4670 pub fn is_trait(&self) -> bool {
4672 TyTrait(..) => true,
4677 pub fn is_integral(&self) -> bool {
4679 TyInfer(IntVar(_)) | TyInt(_) | TyUint(_) => true,
4684 pub fn is_fresh(&self) -> bool {
4686 TyInfer(FreshTy(_)) => true,
4687 TyInfer(FreshIntTy(_)) => true,
4688 TyInfer(FreshFloatTy(_)) => true,
4693 pub fn is_uint(&self) -> bool {
4695 TyInfer(IntVar(_)) | TyUint(ast::TyUs) => true,
4700 pub fn is_char(&self) -> bool {
4707 pub fn is_bare_fn(&self) -> bool {
4709 TyBareFn(..) => true,
4714 pub fn is_bare_fn_item(&self) -> bool {
4716 TyBareFn(Some(_), _) => true,
4721 pub fn is_fp(&self) -> bool {
4723 TyInfer(FloatVar(_)) | TyFloat(_) => true,
4728 pub fn is_numeric(&self) -> bool {
4729 self.is_integral() || self.is_fp()
4732 pub fn is_signed(&self) -> bool {
4739 pub fn is_machine(&self) -> bool {
4741 TyInt(ast::TyIs) | TyUint(ast::TyUs) => false,
4742 TyInt(..) | TyUint(..) | TyFloat(..) => true,
4747 // Whether a type is enum like, that is an enum type with only nullary
4749 pub fn is_c_like_enum(&self, cx: &ctxt) -> bool {
4752 let variants = cx.enum_variants(did);
4753 if variants.is_empty() {
4756 variants.iter().all(|v| v.args.is_empty())
4763 // Returns the type and mutability of *ty.
4765 // The parameter `explicit` indicates if this is an *explicit* dereference.
4766 // Some types---notably unsafe ptrs---can only be dereferenced explicitly.
4767 pub fn builtin_deref(&self, explicit: bool) -> Option<TypeAndMut<'tcx>> {
4772 mutbl: ast::MutImmutable,
4775 TyRef(_, mt) => Some(mt),
4776 TyRawPtr(mt) if explicit => Some(mt),
4781 // Returns the type of ty[i]
4782 pub fn builtin_index(&self) -> Option<Ty<'tcx>> {
4784 TyArray(ty, _) | TySlice(ty) => Some(ty),
4789 pub fn fn_sig(&self) -> &'tcx PolyFnSig<'tcx> {
4791 TyBareFn(_, ref f) => &f.sig,
4792 _ => panic!("Ty::fn_sig() called on non-fn type: {:?}", self)
4796 /// Returns the ABI of the given function.
4797 pub fn fn_abi(&self) -> abi::Abi {
4799 TyBareFn(_, ref f) => f.abi,
4800 _ => panic!("Ty::fn_abi() called on non-fn type"),
4804 // Type accessors for substructures of types
4805 pub fn fn_args(&self) -> ty::Binder<Vec<Ty<'tcx>>> {
4806 self.fn_sig().inputs()
4809 pub fn fn_ret(&self) -> Binder<FnOutput<'tcx>> {
4810 self.fn_sig().output()
4813 pub fn is_fn(&self) -> bool {
4815 TyBareFn(..) => true,
4820 /// See `expr_ty_adjusted`
4821 pub fn adjust<F>(&'tcx self, cx: &ctxt<'tcx>,
4823 expr_id: ast::NodeId,
4824 adjustment: Option<&AutoAdjustment<'tcx>>,
4827 F: FnMut(MethodCall) -> Option<Ty<'tcx>>,
4829 if let TyError = self.sty {
4833 return match adjustment {
4834 Some(adjustment) => {
4836 AdjustReifyFnPointer => {
4838 ty::TyBareFn(Some(_), b) => {
4843 &format!("AdjustReifyFnPointer adjustment on non-fn-item: \
4849 AdjustUnsafeFnPointer => {
4851 ty::TyBareFn(None, b) => cx.safe_to_unsafe_fn_ty(b),
4854 &format!("AdjustReifyFnPointer adjustment on non-fn-item: \
4861 AdjustDerefRef(ref adj) => {
4862 let mut adjusted_ty = self;
4864 if !adjusted_ty.references_error() {
4865 for i in 0..adj.autoderefs {
4866 let method_call = MethodCall::autoderef(expr_id, i as u32);
4867 match method_type(method_call) {
4868 Some(method_ty) => {
4869 // Overloaded deref operators have all late-bound
4870 // regions fully instantiated and coverge.
4872 cx.no_late_bound_regions(&method_ty.fn_ret()).unwrap();
4873 adjusted_ty = fn_ret.unwrap();
4877 match adjusted_ty.builtin_deref(true) {
4878 Some(mt) => { adjusted_ty = mt.ty; }
4882 &format!("the {}th autoderef failed: {}",
4891 if let Some(target) = adj.unsize {
4894 adjusted_ty.adjust_for_autoref(cx, adj.autoref)
4903 pub fn adjust_for_autoref(&'tcx self, cx: &ctxt<'tcx>,
4904 autoref: Option<AutoRef<'tcx>>)
4908 Some(AutoPtr(r, m)) => {
4909 cx.mk_ref(r, TypeAndMut { ty: self, mutbl: m })
4911 Some(AutoUnsafe(m)) => {
4912 cx.mk_ptr(TypeAndMut { ty: self, mutbl: m })
4917 fn sort_string(&self, cx: &ctxt) -> String {
4920 TyBool | TyChar | TyInt(_) |
4921 TyUint(_) | TyFloat(_) | TyStr => self.to_string(),
4922 TyTuple(ref tys) if tys.is_empty() => self.to_string(),
4924 TyEnum(id, _) => format!("enum `{}`", cx.item_path_str(id)),
4925 TyBox(_) => "box".to_string(),
4926 TyArray(_, n) => format!("array of {} elements", n),
4927 TySlice(_) => "slice".to_string(),
4928 TyRawPtr(_) => "*-ptr".to_string(),
4929 TyRef(_, _) => "&-ptr".to_string(),
4930 TyBareFn(Some(_), _) => format!("fn item"),
4931 TyBareFn(None, _) => "fn pointer".to_string(),
4932 TyTrait(ref inner) => {
4933 format!("trait {}", cx.item_path_str(inner.principal_def_id()))
4935 TyStruct(id, _) => {
4936 format!("struct `{}`", cx.item_path_str(id))
4938 TyClosure(..) => "closure".to_string(),
4939 TyTuple(_) => "tuple".to_string(),
4940 TyInfer(TyVar(_)) => "inferred type".to_string(),
4941 TyInfer(IntVar(_)) => "integral variable".to_string(),
4942 TyInfer(FloatVar(_)) => "floating-point variable".to_string(),
4943 TyInfer(FreshTy(_)) => "skolemized type".to_string(),
4944 TyInfer(FreshIntTy(_)) => "skolemized integral type".to_string(),
4945 TyInfer(FreshFloatTy(_)) => "skolemized floating-point type".to_string(),
4946 TyProjection(_) => "associated type".to_string(),
4948 if p.space == subst::SelfSpace {
4951 "type parameter".to_string()
4954 TyError => "type error".to_string(),
4958 /// Explains the source of a type err in a short, human readable way. This is meant to be placed
4959 /// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()`
4960 /// afterwards to present additional details, particularly when it comes to lifetime-related
4962 impl<'tcx> fmt::Display for TypeError<'tcx> {
4963 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
4964 use self::TypeError::*;
4967 CyclicTy => write!(f, "cyclic type of infinite size"),
4968 Mismatch => write!(f, "types differ"),
4969 UnsafetyMismatch(values) => {
4970 write!(f, "expected {} fn, found {} fn",
4974 AbiMismatch(values) => {
4975 write!(f, "expected {} fn, found {} fn",
4979 Mutability => write!(f, "values differ in mutability"),
4981 write!(f, "boxed values differ in mutability")
4983 VecMutability => write!(f, "vectors differ in mutability"),
4984 PtrMutability => write!(f, "pointers differ in mutability"),
4985 RefMutability => write!(f, "references differ in mutability"),
4986 TyParamSize(values) => {
4987 write!(f, "expected a type with {} type params, \
4988 found one with {} type params",
4992 FixedArraySize(values) => {
4993 write!(f, "expected an array with a fixed size of {} elements, \
4994 found one with {} elements",
4998 TupleSize(values) => {
4999 write!(f, "expected a tuple with {} elements, \
5000 found one with {} elements",
5005 write!(f, "incorrect number of function parameters")
5007 RegionsDoesNotOutlive(..) => {
5008 write!(f, "lifetime mismatch")
5010 RegionsNotSame(..) => {
5011 write!(f, "lifetimes are not the same")
5013 RegionsNoOverlap(..) => {
5014 write!(f, "lifetimes do not intersect")
5016 RegionsInsufficientlyPolymorphic(br, _) => {
5017 write!(f, "expected bound lifetime parameter {}, \
5018 found concrete lifetime", br)
5020 RegionsOverlyPolymorphic(br, _) => {
5021 write!(f, "expected concrete lifetime, \
5022 found bound lifetime parameter {}", br)
5024 Sorts(values) => tls::with(|tcx| {
5025 // A naive approach to making sure that we're not reporting silly errors such as:
5026 // (expected closure, found closure).
5027 let expected_str = values.expected.sort_string(tcx);
5028 let found_str = values.found.sort_string(tcx);
5029 if expected_str == found_str {
5030 write!(f, "expected {}, found a different {}", expected_str, found_str)
5032 write!(f, "expected {}, found {}", expected_str, found_str)
5035 Traits(values) => tls::with(|tcx| {
5036 write!(f, "expected trait `{}`, found trait `{}`",
5037 tcx.item_path_str(values.expected),
5038 tcx.item_path_str(values.found))
5040 BuiltinBoundsMismatch(values) => {
5041 if values.expected.is_empty() {
5042 write!(f, "expected no bounds, found `{}`",
5044 } else if values.found.is_empty() {
5045 write!(f, "expected bounds `{}`, found no bounds",
5048 write!(f, "expected bounds `{}`, found bounds `{}`",
5054 write!(f, "expected an integral type, found `char`")
5056 IntMismatch(ref values) => {
5057 write!(f, "expected `{:?}`, found `{:?}`",
5061 FloatMismatch(ref values) => {
5062 write!(f, "expected `{:?}`, found `{:?}`",
5066 VariadicMismatch(ref values) => {
5067 write!(f, "expected {} fn, found {} function",
5068 if values.expected { "variadic" } else { "non-variadic" },
5069 if values.found { "variadic" } else { "non-variadic" })
5071 ConvergenceMismatch(ref values) => {
5072 write!(f, "expected {} fn, found {} function",
5073 if values.expected { "converging" } else { "diverging" },
5074 if values.found { "converging" } else { "diverging" })
5076 ProjectionNameMismatched(ref values) => {
5077 write!(f, "expected {}, found {}",
5081 ProjectionBoundsLength(ref values) => {
5082 write!(f, "expected {} associated type bindings, found {}",
5086 terr_ty_param_default_mismatch(ref values) => {
5087 write!(f, "conflicting type parameter defaults {} and {}",
5095 /// Helper for looking things up in the various maps that are populated during
5096 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
5097 /// these share the pattern that if the id is local, it should have been loaded
5098 /// into the map by the `typeck::collect` phase. If the def-id is external,
5099 /// then we have to go consult the crate loading code (and cache the result for
5101 fn lookup_locally_or_in_crate_store<V, F>(descr: &str,
5103 map: &RefCell<DefIdMap<V>>,
5104 load_external: F) -> V where
5108 match map.borrow().get(&def_id).cloned() {
5109 Some(v) => { return v; }
5113 if def_id.krate == ast::LOCAL_CRATE {
5114 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
5116 let v = load_external();
5117 map.borrow_mut().insert(def_id, v.clone());
5122 pub fn from_mutbl(m: ast::Mutability) -> BorrowKind {
5124 ast::MutMutable => MutBorrow,
5125 ast::MutImmutable => ImmBorrow,
5129 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
5130 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
5131 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
5133 pub fn to_mutbl_lossy(self) -> ast::Mutability {
5135 MutBorrow => ast::MutMutable,
5136 ImmBorrow => ast::MutImmutable,
5138 // We have no type corresponding to a unique imm borrow, so
5139 // use `&mut`. It gives all the capabilities of an `&uniq`
5140 // and hence is a safe "over approximation".
5141 UniqueImmBorrow => ast::MutMutable,
5145 pub fn to_user_str(&self) -> &'static str {
5147 MutBorrow => "mutable",
5148 ImmBorrow => "immutable",
5149 UniqueImmBorrow => "uniquely immutable",
5154 impl<'tcx> ctxt<'tcx> {
5155 /// Returns the type of element at index `i` in tuple or tuple-like type `t`.
5156 /// For an enum `t`, `variant` is None only if `t` is a univariant enum.
5157 pub fn positional_element_ty(&self,
5160 variant: Option<ast::DefId>) -> Option<Ty<'tcx>> {
5162 match (&ty.sty, variant) {
5163 (&TyTuple(ref v), None) => v.get(i).cloned(),
5166 (&TyStruct(def_id, substs), None) => self.lookup_struct_fields(def_id)
5168 .map(|&t| self.lookup_item_type(t.id).ty.subst(self, substs)),
5170 (&TyEnum(def_id, substs), Some(variant_def_id)) => {
5171 let variant_info = self.enum_variant_with_id(def_id, variant_def_id);
5172 variant_info.args.get(i).map(|t|t.subst(self, substs))
5175 (&TyEnum(def_id, substs), None) => {
5176 assert!(self.enum_is_univariant(def_id));
5177 let enum_variants = self.enum_variants(def_id);
5178 let variant_info = &enum_variants[0];
5179 variant_info.args.get(i).map(|t|t.subst(self, substs))
5186 /// Returns the type of element at field `n` in struct or struct-like type `t`.
5187 /// For an enum `t`, `variant` must be some def id.
5188 pub fn named_element_ty(&self,
5191 variant: Option<ast::DefId>) -> Option<Ty<'tcx>> {
5193 match (&ty.sty, variant) {
5194 (&TyStruct(def_id, substs), None) => {
5195 let r = self.lookup_struct_fields(def_id);
5196 r.iter().find(|f| f.name == n)
5197 .map(|&f| self.lookup_field_type(def_id, f.id, substs))
5199 (&TyEnum(def_id, substs), Some(variant_def_id)) => {
5200 let variant_info = self.enum_variant_with_id(def_id, variant_def_id);
5201 variant_info.arg_names.as_ref()
5202 .expect("must have struct enum variant if accessing a named fields")
5203 .iter().zip(&variant_info.args)
5204 .find(|&(&name, _)| name == n)
5205 .map(|(_name, arg_t)| arg_t.subst(self, substs))
5211 pub fn node_id_to_type(&self, id: ast::NodeId) -> Ty<'tcx> {
5212 match self.node_id_to_type_opt(id) {
5214 None => self.sess.bug(
5215 &format!("node_id_to_type: no type for node `{}`",
5216 self.map.node_to_string(id)))
5220 pub fn node_id_to_type_opt(&self, id: ast::NodeId) -> Option<Ty<'tcx>> {
5221 self.tables.borrow().node_types.get(&id).cloned()
5224 pub fn node_id_item_substs(&self, id: ast::NodeId) -> ItemSubsts<'tcx> {
5225 match self.tables.borrow().item_substs.get(&id) {
5226 None => ItemSubsts::empty(),
5227 Some(ts) => ts.clone(),
5231 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
5232 // doesn't provide type parameter substitutions.
5233 pub fn pat_ty(&self, pat: &ast::Pat) -> Ty<'tcx> {
5234 self.node_id_to_type(pat.id)
5236 pub fn pat_ty_opt(&self, pat: &ast::Pat) -> Option<Ty<'tcx>> {
5237 self.node_id_to_type_opt(pat.id)
5240 // Returns the type of an expression as a monotype.
5242 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
5243 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
5244 // auto-ref. The type returned by this function does not consider such
5245 // adjustments. See `expr_ty_adjusted()` instead.
5247 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
5248 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
5249 // instead of "fn(ty) -> T with T = isize".
5250 pub fn expr_ty(&self, expr: &ast::Expr) -> Ty<'tcx> {
5251 self.node_id_to_type(expr.id)
5254 pub fn expr_ty_opt(&self, expr: &ast::Expr) -> Option<Ty<'tcx>> {
5255 self.node_id_to_type_opt(expr.id)
5258 /// Returns the type of `expr`, considering any `AutoAdjustment`
5259 /// entry recorded for that expression.
5261 /// It would almost certainly be better to store the adjusted ty in with
5262 /// the `AutoAdjustment`, but I opted not to do this because it would
5263 /// require serializing and deserializing the type and, although that's not
5264 /// hard to do, I just hate that code so much I didn't want to touch it
5265 /// unless it was to fix it properly, which seemed a distraction from the
5266 /// thread at hand! -nmatsakis
5267 pub fn expr_ty_adjusted(&self, expr: &ast::Expr) -> Ty<'tcx> {
5269 .adjust(self, expr.span, expr.id,
5270 self.tables.borrow().adjustments.get(&expr.id),
5272 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
5276 pub fn expr_span(&self, id: NodeId) -> Span {
5277 match self.map.find(id) {
5278 Some(ast_map::NodeExpr(e)) => {
5282 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
5286 self.sess.bug(&format!("Node id {} is not present \
5287 in the node map", id));
5292 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
5293 match self.map.find(id) {
5294 Some(ast_map::NodeLocal(pat)) => {
5296 ast::PatIdent(_, ref path1, _) => {
5297 token::get_ident(path1.node)
5300 self.sess.bug(&format!("Variable id {} maps to {:?}, not local",
5306 self.sess.bug(&format!("Variable id {} maps to {:?}, not local",
5312 pub fn resolve_expr(&self, expr: &ast::Expr) -> def::Def {
5313 match self.def_map.borrow().get(&expr.id) {
5314 Some(def) => def.full_def(),
5316 self.sess.span_bug(expr.span, &format!(
5317 "no def-map entry for expr {}", expr.id));
5322 pub fn expr_is_lval(&self, expr: &ast::Expr) -> bool {
5324 ast::ExprPath(..) => {
5325 // We can't use resolve_expr here, as this needs to run on broken
5326 // programs. We don't need to through - associated items are all
5328 match self.def_map.borrow().get(&expr.id) {
5329 Some(&def::PathResolution {
5330 base_def: def::DefStatic(..), ..
5331 }) | Some(&def::PathResolution {
5332 base_def: def::DefUpvar(..), ..
5333 }) | Some(&def::PathResolution {
5334 base_def: def::DefLocal(..), ..
5341 None => self.sess.span_bug(expr.span, &format!(
5342 "no def for path {}", expr.id))
5346 ast::ExprUnary(ast::UnDeref, _) |
5347 ast::ExprField(..) |
5348 ast::ExprTupField(..) |
5349 ast::ExprIndex(..) => {
5354 ast::ExprMethodCall(..) |
5355 ast::ExprStruct(..) |
5356 ast::ExprRange(..) |
5359 ast::ExprMatch(..) |
5360 ast::ExprClosure(..) |
5361 ast::ExprBlock(..) |
5362 ast::ExprRepeat(..) |
5364 ast::ExprBreak(..) |
5365 ast::ExprAgain(..) |
5367 ast::ExprWhile(..) |
5369 ast::ExprAssign(..) |
5370 ast::ExprInlineAsm(..) |
5371 ast::ExprAssignOp(..) |
5373 ast::ExprUnary(..) |
5375 ast::ExprAddrOf(..) |
5376 ast::ExprBinary(..) |
5377 ast::ExprCast(..) => {
5381 ast::ExprParen(ref e) => self.expr_is_lval(e),
5383 ast::ExprIfLet(..) |
5384 ast::ExprWhileLet(..) |
5385 ast::ExprForLoop(..) |
5386 ast::ExprMac(..) => {
5389 "macro expression remains after expansion");
5394 pub fn field_idx_strict(&self, name: ast::Name, fields: &[Field<'tcx>])
5397 for f in fields { if f.name == name { return i; } i += 1; }
5398 self.sess.bug(&format!(
5399 "no field named `{}` found in the list of fields `{:?}`",
5400 token::get_name(name),
5402 .map(|f| token::get_name(f.name).to_string())
5403 .collect::<Vec<String>>()));
5406 pub fn note_and_explain_type_err(&self, err: &TypeError<'tcx>, sp: Span) {
5407 use self::TypeError::*;
5410 RegionsDoesNotOutlive(subregion, superregion) => {
5411 self.note_and_explain_region("", subregion, "...");
5412 self.note_and_explain_region("...does not necessarily outlive ",
5415 RegionsNotSame(region1, region2) => {
5416 self.note_and_explain_region("", region1, "...");
5417 self.note_and_explain_region("...is not the same lifetime as ",
5420 RegionsNoOverlap(region1, region2) => {
5421 self.note_and_explain_region("", region1, "...");
5422 self.note_and_explain_region("...does not overlap ",
5425 RegionsInsufficientlyPolymorphic(_, conc_region) => {
5426 self.note_and_explain_region("concrete lifetime that was found is ",
5429 RegionsOverlyPolymorphic(_, ty::ReInfer(ty::ReVar(_))) => {
5430 // don't bother to print out the message below for
5431 // inference variables, it's not very illuminating.
5433 RegionsOverlyPolymorphic(_, conc_region) => {
5434 self.note_and_explain_region("expected concrete lifetime is ",
5438 let expected_str = values.expected.sort_string(self);
5439 let found_str = values.found.sort_string(self);
5440 if expected_str == found_str && expected_str == "closure" {
5441 self.sess.span_note(sp,
5442 &format!("no two closures, even if identical, have the same type"));
5443 self.sess.span_help(sp,
5444 &format!("consider boxing your closure and/or \
5445 using it as a trait object"));
5448 terr_ty_param_default_mismatch(values) => {
5449 let expected = values.expected;
5450 let found = values.found;
5451 self.sess.span_note(sp,
5452 &format!("conflicting type parameter defaults {} and {}",
5455 self.sess.span_note(expected.definition_span,
5456 &format!("...a default was defined"));
5457 self.sess.span_note(expected.origin_span,
5458 &format!("...that was applied to an unconstrained type variable here"));
5459 self.sess.span_note(found.definition_span,
5460 &format!("...a second default was defined"));
5461 self.sess.span_note(found.origin_span,
5462 &format!("...that also applies to the same type variable here"));
5468 pub fn provided_source(&self, id: ast::DefId) -> Option<ast::DefId> {
5469 self.provided_method_sources.borrow().get(&id).cloned()
5472 pub fn provided_trait_methods(&self, id: ast::DefId) -> Vec<Rc<Method<'tcx>>> {
5474 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id.node).node {
5475 ms.iter().filter_map(|ti| {
5476 if let ast::MethodTraitItem(_, Some(_)) = ti.node {
5477 match self.impl_or_trait_item(ast_util::local_def(ti.id)) {
5478 MethodTraitItem(m) => Some(m),
5480 self.sess.bug("provided_trait_methods(): \
5481 non-method item found from \
5482 looking up provided method?!")
5490 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
5493 csearch::get_provided_trait_methods(self, id)
5497 pub fn associated_consts(&self, id: ast::DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
5499 match self.map.expect_item(id.node).node {
5500 ItemTrait(_, _, _, ref tis) => {
5501 tis.iter().filter_map(|ti| {
5502 if let ast::ConstTraitItem(_, _) = ti.node {
5503 match self.impl_or_trait_item(ast_util::local_def(ti.id)) {
5504 ConstTraitItem(ac) => Some(ac),
5506 self.sess.bug("associated_consts(): \
5507 non-const item found from \
5508 looking up a constant?!")
5516 ItemImpl(_, _, _, _, _, ref iis) => {
5517 iis.iter().filter_map(|ii| {
5518 if let ast::ConstImplItem(_, _) = ii.node {
5519 match self.impl_or_trait_item(ast_util::local_def(ii.id)) {
5520 ConstTraitItem(ac) => Some(ac),
5522 self.sess.bug("associated_consts(): \
5523 non-const item found from \
5524 looking up a constant?!")
5533 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
5538 csearch::get_associated_consts(self, id)
5542 pub fn trait_items(&self, trait_did: ast::DefId) -> Rc<Vec<ImplOrTraitItem<'tcx>>> {
5543 let mut trait_items = self.trait_items_cache.borrow_mut();
5544 match trait_items.get(&trait_did).cloned() {
5545 Some(trait_items) => trait_items,
5547 let def_ids = self.trait_item_def_ids(trait_did);
5548 let items: Rc<Vec<ImplOrTraitItem>> =
5549 Rc::new(def_ids.iter()
5550 .map(|d| self.impl_or_trait_item(d.def_id()))
5552 trait_items.insert(trait_did, items.clone());
5558 pub fn trait_impl_polarity(&self, id: ast::DefId) -> Option<ast::ImplPolarity> {
5559 if id.krate == ast::LOCAL_CRATE {
5560 match self.map.find(id.node) {
5561 Some(ast_map::NodeItem(item)) => {
5563 ast::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
5570 csearch::get_impl_polarity(self, id)
5574 pub fn custom_coerce_unsized_kind(&self, did: ast::DefId) -> CustomCoerceUnsized {
5575 memoized(&self.custom_coerce_unsized_kinds, did, |did: DefId| {
5576 let (kind, src) = if did.krate != ast::LOCAL_CRATE {
5577 (csearch::get_custom_coerce_unsized_kind(self, did), "external")
5585 self.sess.bug(&format!("custom_coerce_unsized_kind: \
5586 {} impl `{}` is missing its kind",
5587 src, self.item_path_str(did)));
5593 pub fn impl_or_trait_item(&self, id: ast::DefId) -> ImplOrTraitItem<'tcx> {
5594 lookup_locally_or_in_crate_store(
5595 "impl_or_trait_items", id, &self.impl_or_trait_items,
5596 || csearch::get_impl_or_trait_item(self, id))
5599 pub fn trait_item_def_ids(&self, id: ast::DefId) -> Rc<Vec<ImplOrTraitItemId>> {
5600 lookup_locally_or_in_crate_store(
5601 "trait_item_def_ids", id, &self.trait_item_def_ids,
5602 || Rc::new(csearch::get_trait_item_def_ids(&self.sess.cstore, id)))
5605 /// Returns the trait-ref corresponding to a given impl, or None if it is
5606 /// an inherent impl.
5607 pub fn impl_trait_ref(&self, id: ast::DefId) -> Option<TraitRef<'tcx>> {
5608 lookup_locally_or_in_crate_store(
5609 "impl_trait_refs", id, &self.impl_trait_refs,
5610 || csearch::get_impl_trait(self, id))
5613 /// Returns whether this DefId refers to an impl
5614 pub fn is_impl(&self, id: ast::DefId) -> bool {
5615 if id.krate == ast::LOCAL_CRATE {
5616 if let Some(ast_map::NodeItem(
5617 &ast::Item { node: ast::ItemImpl(..), .. })) = self.map.find(id.node) {
5623 csearch::is_impl(&self.sess.cstore, id)
5627 pub fn trait_ref_to_def_id(&self, tr: &ast::TraitRef) -> ast::DefId {
5628 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
5631 pub fn try_add_builtin_trait(&self,
5632 trait_def_id: ast::DefId,
5633 builtin_bounds: &mut EnumSet<BuiltinBound>)
5636 //! Checks whether `trait_ref` refers to one of the builtin
5637 //! traits, like `Send`, and adds the corresponding
5638 //! bound to the set `builtin_bounds` if so. Returns true if `trait_ref`
5639 //! is a builtin trait.
5641 match self.lang_items.to_builtin_kind(trait_def_id) {
5642 Some(bound) => { builtin_bounds.insert(bound); true }
5647 pub fn substd_enum_variants(&self,
5649 substs: &Substs<'tcx>)
5650 -> Vec<Rc<VariantInfo<'tcx>>> {
5651 self.enum_variants(id).iter().map(|variant_info| {
5652 let substd_args = variant_info.args.iter()
5653 .map(|aty| aty.subst(self, substs)).collect::<Vec<_>>();
5655 let substd_ctor_ty = variant_info.ctor_ty.subst(self, substs);
5657 Rc::new(VariantInfo {
5659 ctor_ty: substd_ctor_ty,
5660 ..(**variant_info).clone()
5665 pub fn item_path_str(&self, id: ast::DefId) -> String {
5666 self.with_path(id, |path| ast_map::path_to_string(path))
5669 /* If struct_id names a struct with a dtor. */
5670 pub fn ty_dtor(&self, struct_id: DefId) -> DtorKind {
5671 match self.destructor_for_type.borrow().get(&struct_id) {
5672 Some(&method_def_id) => {
5673 let flag = !self.has_attr(struct_id, "unsafe_no_drop_flag");
5675 TraitDtor(method_def_id, flag)
5681 pub fn has_dtor(&self, struct_id: DefId) -> bool {
5682 self.destructor_for_type.borrow().contains_key(&struct_id)
5685 pub fn with_path<T, F>(&self, id: ast::DefId, f: F) -> T where
5686 F: FnOnce(ast_map::PathElems) -> T,
5688 if id.krate == ast::LOCAL_CRATE {
5689 self.map.with_path(id.node, f)
5691 f(csearch::get_item_path(self, id).iter().cloned().chain(LinkedPath::empty()))
5695 pub fn enum_is_univariant(&self, id: ast::DefId) -> bool {
5696 self.enum_variants(id).len() == 1
5699 /// Returns `(normalized_type, ty)`, where `normalized_type` is the
5700 /// IntType representation of one of {i64,i32,i16,i8,u64,u32,u16,u8},
5701 /// and `ty` is the original type (i.e. may include `isize` or
5703 pub fn enum_repr_type(&self, opt_hint: Option<&attr::ReprAttr>)
5704 -> (attr::IntType, Ty<'tcx>) {
5705 let repr_type = match opt_hint {
5706 // Feed in the given type
5707 Some(&attr::ReprInt(_, int_t)) => int_t,
5708 // ... but provide sensible default if none provided
5710 // NB. Historically `fn enum_variants` generate i64 here, while
5711 // rustc_typeck::check would generate isize.
5712 _ => SignedInt(ast::TyIs),
5715 let repr_type_ty = repr_type.to_ty(self);
5716 let repr_type = match repr_type {
5717 SignedInt(ast::TyIs) =>
5718 SignedInt(self.sess.target.int_type),
5719 UnsignedInt(ast::TyUs) =>
5720 UnsignedInt(self.sess.target.uint_type),
5724 (repr_type, repr_type_ty)
5727 fn report_discrim_overflow(&self,
5730 repr_type: attr::IntType,
5732 let computed_value = repr_type.disr_wrap_incr(Some(prev_val));
5733 let computed_value = repr_type.disr_string(computed_value);
5734 let prev_val = repr_type.disr_string(prev_val);
5735 let repr_type = repr_type.to_ty(self);
5736 span_err!(self.sess, variant_span, E0370,
5737 "enum discriminant overflowed on value after {}: {}; \
5738 set explicitly via {} = {} if that is desired outcome",
5739 prev_val, repr_type, variant_name, computed_value);
5742 // This computes the discriminant values for the sequence of Variants
5743 // attached to a particular enum, taking into account the #[repr] (if
5744 // any) provided via the `opt_hint`.
5745 fn compute_enum_variants(&self,
5746 vs: &'tcx [P<ast::Variant>],
5747 opt_hint: Option<&attr::ReprAttr>)
5748 -> Vec<Rc<ty::VariantInfo<'tcx>>> {
5749 let mut variants: Vec<Rc<ty::VariantInfo>> = Vec::new();
5750 let mut prev_disr_val: Option<ty::Disr> = None;
5752 let (repr_type, repr_type_ty) = self.enum_repr_type(opt_hint);
5755 // If the discriminant value is specified explicitly in the
5756 // enum, check whether the initialization expression is valid,
5757 // otherwise use the last value plus one.
5758 let current_disr_val;
5760 // This closure marks cases where, when an error occurs during
5761 // the computation, attempt to assign a (hopefully) fresh
5762 // value to avoid spurious error reports downstream.
5763 let attempt_fresh_value = move || -> Disr {
5764 repr_type.disr_wrap_incr(prev_disr_val)
5767 match v.node.disr_expr {
5769 debug!("disr expr, checking {}", pprust::expr_to_string(&**e));
5771 let hint = UncheckedExprHint(repr_type_ty);
5772 match const_eval::eval_const_expr_partial(self, &**e, hint) {
5773 Ok(ConstVal::Int(val)) => current_disr_val = val as Disr,
5774 Ok(ConstVal::Uint(val)) => current_disr_val = val as Disr,
5776 let sign_desc = if repr_type.is_signed() {
5781 span_err!(self.sess, e.span, E0079,
5782 "expected {} integer constant",
5784 current_disr_val = attempt_fresh_value();
5787 span_err!(self.sess, err.span, E0080,
5788 "constant evaluation error: {}",
5790 current_disr_val = attempt_fresh_value();
5795 current_disr_val = match prev_disr_val {
5796 Some(prev_disr_val) => {
5797 if let Some(v) = repr_type.disr_incr(prev_disr_val) {
5800 self.report_discrim_overflow(v.span, v.node.name.as_str(),
5801 repr_type, prev_disr_val);
5802 attempt_fresh_value()
5805 None => ty::INITIAL_DISCRIMINANT_VALUE
5810 let variant_info = Rc::new(VariantInfo::from_ast_variant(self, &**v, current_disr_val));
5811 prev_disr_val = Some(current_disr_val);
5813 variants.push(variant_info);
5819 pub fn enum_variants(&self, id: ast::DefId) -> Rc<Vec<Rc<VariantInfo<'tcx>>>> {
5820 memoized(&self.enum_var_cache, id, |id: ast::DefId| {
5821 if ast::LOCAL_CRATE != id.krate {
5822 Rc::new(csearch::get_enum_variants(self, id))
5824 match self.map.get(id.node) {
5825 ast_map::NodeItem(ref item) => {
5827 ast::ItemEnum(ref enum_definition, _) => {
5828 Rc::new(self.compute_enum_variants(
5829 &enum_definition.variants,
5830 self.lookup_repr_hints(id).get(0)))
5833 self.sess.bug("enum_variants: id not bound to an enum")
5837 _ => self.sess.bug("enum_variants: id not bound to an enum")
5843 // Returns information about the enum variant with the given ID:
5844 pub fn enum_variant_with_id(&self,
5845 enum_id: ast::DefId,
5846 variant_id: ast::DefId)
5847 -> Rc<VariantInfo<'tcx>> {
5848 self.enum_variants(enum_id).iter()
5849 .find(|variant| variant.id == variant_id)
5850 .expect("enum_variant_with_id(): no variant exists with that ID")
5854 // Register a given item type
5855 pub fn register_item_type(&self, did: ast::DefId, ty: TypeScheme<'tcx>) {
5856 self.tcache.borrow_mut().insert(did, ty);
5859 // If the given item is in an external crate, looks up its type and adds it to
5860 // the type cache. Returns the type parameters and type.
5861 pub fn lookup_item_type(&self, did: ast::DefId) -> TypeScheme<'tcx> {
5862 lookup_locally_or_in_crate_store(
5863 "tcache", did, &self.tcache,
5864 || csearch::get_type(self, did))
5867 /// Given the did of a trait, returns its canonical trait ref.
5868 pub fn lookup_trait_def(&self, did: ast::DefId) -> &'tcx TraitDef<'tcx> {
5869 lookup_locally_or_in_crate_store(
5870 "trait_defs", did, &self.trait_defs,
5871 || self.arenas.trait_defs.alloc(csearch::get_trait_def(self, did))
5875 /// Given the did of an item, returns its full set of predicates.
5876 pub fn lookup_predicates(&self, did: ast::DefId) -> GenericPredicates<'tcx> {
5877 lookup_locally_or_in_crate_store(
5878 "predicates", did, &self.predicates,
5879 || csearch::get_predicates(self, did))
5882 /// Given the did of a trait, returns its superpredicates.
5883 pub fn lookup_super_predicates(&self, did: ast::DefId) -> GenericPredicates<'tcx> {
5884 lookup_locally_or_in_crate_store(
5885 "super_predicates", did, &self.super_predicates,
5886 || csearch::get_super_predicates(self, did))
5889 /// Get the attributes of a definition.
5890 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [ast::Attribute]> {
5892 Cow::Borrowed(self.map.attrs(did.node))
5894 Cow::Owned(csearch::get_item_attrs(&self.sess.cstore, did))
5898 /// Determine whether an item is annotated with an attribute
5899 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
5900 self.get_attrs(did).iter().any(|item| item.check_name(attr))
5903 /// Determine whether an item is annotated with `#[repr(packed)]`
5904 pub fn lookup_packed(&self, did: DefId) -> bool {
5905 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
5908 /// Determine whether an item is annotated with `#[simd]`
5909 pub fn lookup_simd(&self, did: DefId) -> bool {
5910 self.has_attr(did, "simd")
5913 /// Obtain the representation annotation for a struct definition.
5914 pub fn lookup_repr_hints(&self, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
5915 memoized(&self.repr_hint_cache, did, |did: DefId| {
5916 Rc::new(if did.krate == LOCAL_CRATE {
5917 self.get_attrs(did).iter().flat_map(|meta| {
5918 attr::find_repr_attrs(self.sess.diagnostic(), meta).into_iter()
5921 csearch::get_repr_attrs(&self.sess.cstore, did)
5926 // Look up a field ID, whether or not it's local
5927 pub fn lookup_field_type_unsubstituted(&self,
5931 if id.krate == ast::LOCAL_CRATE {
5932 self.node_id_to_type(id.node)
5934 memoized(&self.tcache, id,
5935 |id| csearch::get_field_type(self, struct_id, id)).ty
5940 // Look up a field ID, whether or not it's local
5941 // Takes a list of type substs in case the struct is generic
5942 pub fn lookup_field_type(&self,
5945 substs: &Substs<'tcx>)
5947 self.lookup_field_type_unsubstituted(struct_id, id).subst(self, substs)
5950 // Look up the list of field names and IDs for a given struct.
5951 // Panics if the id is not bound to a struct.
5952 pub fn lookup_struct_fields(&self, did: ast::DefId) -> Vec<FieldTy> {
5953 if did.krate == ast::LOCAL_CRATE {
5954 let struct_fields = self.struct_fields.borrow();
5955 match struct_fields.get(&did) {
5956 Some(fields) => (**fields).clone(),
5959 &format!("ID not mapped to struct fields: {}",
5960 self.map.node_to_string(did.node)));
5964 csearch::get_struct_fields(&self.sess.cstore, did)
5968 pub fn is_tuple_struct(&self, did: ast::DefId) -> bool {
5969 let fields = self.lookup_struct_fields(did);
5970 !fields.is_empty() && fields.iter().all(|f| f.name == token::special_names::unnamed_field)
5973 // Returns a list of fields corresponding to the struct's items. trans uses
5974 // this. Takes a list of substs with which to instantiate field types.
5975 pub fn struct_fields(&self, did: ast::DefId, substs: &Substs<'tcx>)
5976 -> Vec<Field<'tcx>> {
5977 self.lookup_struct_fields(did).iter().map(|f| {
5981 ty: self.lookup_field_type(did, f.id, substs),
5988 /// Returns the deeply last field of nested structures, or the same type,
5989 /// if not a structure at all. Corresponds to the only possible unsized
5990 /// field, and its type can be used to determine unsizing strategy.
5991 pub fn struct_tail(&self, mut ty: Ty<'tcx>) -> Ty<'tcx> {
5992 while let TyStruct(def_id, substs) = ty.sty {
5993 match self.struct_fields(def_id, substs).last() {
5994 Some(f) => ty = f.mt.ty,
6001 /// Same as applying struct_tail on `source` and `target`, but only
6002 /// keeps going as long as the two types are instances of the same
6003 /// structure definitions.
6004 /// For `(Foo<Foo<T>>, Foo<Trait>)`, the result will be `(Foo<T>, Trait)`,
6005 /// whereas struct_tail produces `T`, and `Trait`, respectively.
6006 pub fn struct_lockstep_tails(&self,
6009 -> (Ty<'tcx>, Ty<'tcx>) {
6010 let (mut a, mut b) = (source, target);
6011 while let (&TyStruct(a_did, a_substs), &TyStruct(b_did, b_substs)) = (&a.sty, &b.sty) {
6015 if let Some(a_f) = self.struct_fields(a_did, a_substs).last() {
6016 if let Some(b_f) = self.struct_fields(b_did, b_substs).last() {
6029 // Returns the repeat count for a repeating vector expression.
6030 pub fn eval_repeat_count(&self, count_expr: &ast::Expr) -> usize {
6031 let hint = UncheckedExprHint(self.types.usize);
6032 match const_eval::eval_const_expr_partial(self, count_expr, hint) {
6034 let found = match val {
6035 ConstVal::Uint(count) => return count as usize,
6036 ConstVal::Int(count) if count >= 0 => return count as usize,
6037 const_val => const_val.description(),
6039 span_err!(self.sess, count_expr.span, E0306,
6040 "expected positive integer for repeat count, found {}",
6044 let err_description = err.description();
6045 let found = match count_expr.node {
6046 ast::ExprPath(None, ast::Path {
6050 }) if segments.len() == 1 =>
6051 format!("{}", "found variable"),
6053 format!("but {}", err_description),
6055 span_err!(self.sess, count_expr.span, E0307,
6056 "expected constant integer for repeat count, {}",
6063 // Iterate over a type parameter's bounded traits and any supertraits
6064 // of those traits, ignoring kinds.
6065 // Here, the supertraits are the transitive closure of the supertrait
6066 // relation on the supertraits from each bounded trait's constraint
6068 pub fn each_bound_trait_and_supertraits<F>(&self,
6069 bounds: &[PolyTraitRef<'tcx>],
6072 F: FnMut(PolyTraitRef<'tcx>) -> bool,
6074 for bound_trait_ref in traits::transitive_bounds(self, bounds) {
6075 if !f(bound_trait_ref) {
6082 /// Given a set of predicates that apply to an object type, returns
6083 /// the region bounds that the (erased) `Self` type must
6084 /// outlive. Precisely *because* the `Self` type is erased, the
6085 /// parameter `erased_self_ty` must be supplied to indicate what type
6086 /// has been used to represent `Self` in the predicates
6087 /// themselves. This should really be a unique type; `FreshTy(0)` is a
6090 /// Requires that trait definitions have been processed so that we can
6091 /// elaborate predicates and walk supertraits.
6092 pub fn required_region_bounds(&self,
6093 erased_self_ty: Ty<'tcx>,
6094 predicates: Vec<ty::Predicate<'tcx>>)
6097 debug!("required_region_bounds(erased_self_ty={:?}, predicates={:?})",
6101 assert!(!erased_self_ty.has_escaping_regions());
6103 traits::elaborate_predicates(self, predicates)
6104 .filter_map(|predicate| {
6106 ty::Predicate::Projection(..) |
6107 ty::Predicate::Trait(..) |
6108 ty::Predicate::Equate(..) |
6109 ty::Predicate::RegionOutlives(..) => {
6112 ty::Predicate::TypeOutlives(ty::Binder(ty::OutlivesPredicate(t, r))) => {
6113 // Search for a bound of the form `erased_self_ty
6114 // : 'a`, but be wary of something like `for<'a>
6115 // erased_self_ty : 'a` (we interpret a
6116 // higher-ranked bound like that as 'static,
6117 // though at present the code in `fulfill.rs`
6118 // considers such bounds to be unsatisfiable, so
6119 // it's kind of a moot point since you could never
6120 // construct such an object, but this seems
6121 // correct even if that code changes).
6122 if t == erased_self_ty && !r.has_escaping_regions() {
6123 if r.has_escaping_regions() {
6137 pub fn item_variances(&self, item_id: ast::DefId) -> Rc<ItemVariances> {
6138 lookup_locally_or_in_crate_store(
6139 "item_variance_map", item_id, &self.item_variance_map,
6140 || Rc::new(csearch::get_item_variances(&self.sess.cstore, item_id)))
6143 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
6144 self.populate_implementations_for_trait_if_necessary(trait_def_id);
6146 let def = self.lookup_trait_def(trait_def_id);
6147 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
6150 /// Records a trait-to-implementation mapping.
6151 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
6152 let def = self.lookup_trait_def(trait_def_id);
6153 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
6156 /// Load primitive inherent implementations if necessary
6157 pub fn populate_implementations_for_primitive_if_necessary(&self,
6158 primitive_def_id: ast::DefId) {
6159 if primitive_def_id.krate == LOCAL_CRATE {
6163 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
6167 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
6170 let impl_items = csearch::get_impl_items(&self.sess.cstore, primitive_def_id);
6172 // Store the implementation info.
6173 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
6174 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
6177 /// Populates the type context with all the inherent implementations for
6178 /// the given type if necessary.
6179 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
6180 type_id: ast::DefId) {
6181 if type_id.krate == LOCAL_CRATE {
6185 if self.populated_external_types.borrow().contains(&type_id) {
6189 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
6192 let mut inherent_impls = Vec::new();
6193 csearch::each_inherent_implementation_for_type(&self.sess.cstore, type_id, |impl_def_id| {
6194 // Record the implementation.
6195 inherent_impls.push(impl_def_id);
6197 // Store the implementation info.
6198 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
6199 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
6202 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
6203 self.populated_external_types.borrow_mut().insert(type_id);
6206 /// Populates the type context with all the implementations for the given
6207 /// trait if necessary.
6208 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: ast::DefId) {
6209 if trait_id.krate == LOCAL_CRATE {
6213 let def = self.lookup_trait_def(trait_id);
6214 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
6218 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
6220 if csearch::is_defaulted_trait(&self.sess.cstore, trait_id) {
6221 self.record_trait_has_default_impl(trait_id);
6224 csearch::each_implementation_for_trait(&self.sess.cstore, trait_id, |impl_def_id| {
6225 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
6226 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
6227 // Record the trait->implementation mapping.
6228 def.record_impl(self, impl_def_id, trait_ref);
6230 // For any methods that use a default implementation, add them to
6231 // the map. This is a bit unfortunate.
6232 for impl_item_def_id in &impl_items {
6233 let method_def_id = impl_item_def_id.def_id();
6234 match self.impl_or_trait_item(method_def_id) {
6235 MethodTraitItem(method) => {
6236 if let Some(source) = method.provided_source {
6237 self.provided_method_sources
6239 .insert(method_def_id, source);
6246 // Store the implementation info.
6247 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
6250 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
6253 /// Given the def_id of an impl, return the def_id of the trait it implements.
6254 /// If it implements no trait, return `None`.
6255 pub fn trait_id_of_impl(&self, def_id: ast::DefId) -> Option<ast::DefId> {
6256 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
6259 /// If the given def ID describes a method belonging to an impl, return the
6260 /// ID of the impl that the method belongs to. Otherwise, return `None`.
6261 pub fn impl_of_method(&self, def_id: ast::DefId) -> Option<ast::DefId> {
6262 if def_id.krate != LOCAL_CRATE {
6263 return match csearch::get_impl_or_trait_item(self,
6264 def_id).container() {
6265 TraitContainer(_) => None,
6266 ImplContainer(def_id) => Some(def_id),
6269 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
6270 Some(trait_item) => {
6271 match trait_item.container() {
6272 TraitContainer(_) => None,
6273 ImplContainer(def_id) => Some(def_id),
6280 /// If the given def ID describes an item belonging to a trait (either a
6281 /// default method or an implementation of a trait method), return the ID of
6282 /// the trait that the method belongs to. Otherwise, return `None`.
6283 pub fn trait_of_item(&self, def_id: ast::DefId) -> Option<ast::DefId> {
6284 if def_id.krate != LOCAL_CRATE {
6285 return csearch::get_trait_of_item(&self.sess.cstore, def_id, self);
6287 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
6288 Some(impl_or_trait_item) => {
6289 match impl_or_trait_item.container() {
6290 TraitContainer(def_id) => Some(def_id),
6291 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
6298 /// If the given def ID describes an item belonging to a trait, (either a
6299 /// default method or an implementation of a trait method), return the ID of
6300 /// the method inside trait definition (this means that if the given def ID
6301 /// is already that of the original trait method, then the return value is
6303 /// Otherwise, return `None`.
6304 pub fn trait_item_of_item(&self, def_id: ast::DefId) -> Option<ImplOrTraitItemId> {
6305 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
6306 Some(m) => m.clone(),
6307 None => return None,
6309 let name = impl_item.name();
6310 match self.trait_of_item(def_id) {
6311 Some(trait_did) => {
6312 self.trait_items(trait_did).iter()
6313 .find(|item| item.name() == name)
6314 .map(|item| item.id())
6320 /// Creates a hash of the type `Ty` which will be the same no matter what crate
6321 /// context it's calculated within. This is used by the `type_id` intrinsic.
6322 pub fn hash_crate_independent(&self, ty: Ty<'tcx>, svh: &Svh) -> u64 {
6323 let mut state = SipHasher::new();
6324 helper(self, ty, svh, &mut state);
6325 return state.finish();
6327 fn helper<'tcx>(tcx: &ctxt<'tcx>, ty: Ty<'tcx>, svh: &Svh,
6328 state: &mut SipHasher) {
6329 macro_rules! byte { ($b:expr) => { ($b as u8).hash(state) } }
6330 macro_rules! hash { ($e:expr) => { $e.hash(state) } }
6332 let region = |state: &mut SipHasher, r: Region| {
6335 ReLateBound(db, BrAnon(i)) => {
6345 tcx.sess.bug("unexpected region found when hashing a type")
6349 let did = |state: &mut SipHasher, did: DefId| {
6350 let h = if ast_util::is_local(did) {
6353 tcx.sess.cstore.get_crate_hash(did.krate)
6355 h.as_str().hash(state);
6356 did.node.hash(state);
6358 let mt = |state: &mut SipHasher, mt: TypeAndMut| {
6359 mt.mutbl.hash(state);
6361 let fn_sig = |state: &mut SipHasher, sig: &Binder<FnSig<'tcx>>| {
6362 let sig = tcx.anonymize_late_bound_regions(sig).0;
6363 for a in &sig.inputs { helper(tcx, *a, svh, state); }
6364 if let ty::FnConverging(output) = sig.output {
6365 helper(tcx, output, svh, state);
6368 ty.maybe_walk(|ty| {
6410 TyBareFn(opt_def_id, ref b) => {
6415 fn_sig(state, &b.sig);
6418 TyTrait(ref data) => {
6420 did(state, data.principal_def_id());
6423 let principal = tcx.anonymize_late_bound_regions(&data.principal).0;
6424 for subty in &principal.substs.types {
6425 helper(tcx, subty, svh, state);
6434 TyTuple(ref inner) => {
6442 hash!(token::get_name(p.name));
6444 TyInfer(_) => unreachable!(),
6445 TyError => byte!(21),
6446 TyClosure(d, _) => {
6450 TyProjection(ref data) => {
6452 did(state, data.trait_ref.def_id);
6453 hash!(token::get_name(data.item_name));
6461 /// Construct a parameter environment suitable for static contexts or other contexts where there
6462 /// are no free type/lifetime parameters in scope.
6463 pub fn empty_parameter_environment<'a>(&'a self) -> ParameterEnvironment<'a,'tcx> {
6464 ty::ParameterEnvironment { tcx: self,
6465 free_substs: Substs::empty(),
6466 caller_bounds: Vec::new(),
6467 implicit_region_bound: ty::ReEmpty,
6468 selection_cache: traits::SelectionCache::new(), }
6471 /// Constructs and returns a substitution that can be applied to move from
6472 /// the "outer" view of a type or method to the "inner" view.
6473 /// In general, this means converting from bound parameters to
6474 /// free parameters. Since we currently represent bound/free type
6475 /// parameters in the same way, this only has an effect on regions.
6476 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
6477 free_id: ast::NodeId) -> Substs<'tcx> {
6479 let mut types = VecPerParamSpace::empty();
6480 for def in generics.types.as_slice() {
6481 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
6483 types.push(def.space, self.mk_param_from_def(def));
6486 let free_id_outlive = region::DestructionScopeData::new(free_id);
6488 // map bound 'a => free 'a
6489 let mut regions = VecPerParamSpace::empty();
6490 for def in generics.regions.as_slice() {
6492 ReFree(FreeRegion { scope: free_id_outlive,
6493 bound_region: BrNamed(def.def_id, def.name) });
6494 debug!("push_region_params {:?}", region);
6495 regions.push(def.space, region);
6500 regions: subst::NonerasedRegions(regions)
6504 /// See `ParameterEnvironment` struct def'n for details
6505 pub fn construct_parameter_environment<'a>(&'a self,
6507 generics: &ty::Generics<'tcx>,
6508 generic_predicates: &ty::GenericPredicates<'tcx>,
6509 free_id: ast::NodeId)
6510 -> ParameterEnvironment<'a, 'tcx>
6513 // Construct the free substs.
6516 let free_substs = self.construct_free_substs(generics, free_id);
6517 let free_id_outlive = region::DestructionScopeData::new(free_id);
6520 // Compute the bounds on Self and the type parameters.
6523 let bounds = generic_predicates.instantiate(self, &free_substs);
6524 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
6525 let predicates = bounds.predicates.into_vec();
6527 debug!("construct_parameter_environment: free_id={:?} free_subst={:?} predicates={:?}",
6533 // Finally, we have to normalize the bounds in the environment, in
6534 // case they contain any associated type projections. This process
6535 // can yield errors if the put in illegal associated types, like
6536 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
6537 // report these errors right here; this doesn't actually feel
6538 // right to me, because constructing the environment feels like a
6539 // kind of a "idempotent" action, but I'm not sure where would be
6540 // a better place. In practice, we construct environments for
6541 // every fn once during type checking, and we'll abort if there
6542 // are any errors at that point, so after type checking you can be
6543 // sure that this will succeed without errors anyway.
6546 let unnormalized_env = ty::ParameterEnvironment {
6548 free_substs: free_substs,
6549 implicit_region_bound: ty::ReScope(free_id_outlive.to_code_extent()),
6550 caller_bounds: predicates,
6551 selection_cache: traits::SelectionCache::new(),
6554 let cause = traits::ObligationCause::misc(span, free_id);
6555 traits::normalize_param_env_or_error(unnormalized_env, cause)
6558 pub fn is_method_call(&self, expr_id: ast::NodeId) -> bool {
6559 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
6562 pub fn is_overloaded_autoderef(&self, expr_id: ast::NodeId, autoderefs: u32) -> bool {
6563 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
6567 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
6568 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
6572 /// The category of explicit self.
6573 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
6574 pub enum ExplicitSelfCategory {
6575 StaticExplicitSelfCategory,
6576 ByValueExplicitSelfCategory,
6577 ByReferenceExplicitSelfCategory(Region, ast::Mutability),
6578 ByBoxExplicitSelfCategory,
6581 /// A free variable referred to in a function.
6582 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
6583 pub struct Freevar {
6584 /// The variable being accessed free.
6587 // First span where it is accessed (there can be multiple).
6591 pub type FreevarMap = NodeMap<Vec<Freevar>>;
6593 pub type CaptureModeMap = NodeMap<ast::CaptureClause>;
6595 // Trait method resolution
6596 pub type TraitMap = NodeMap<Vec<DefId>>;
6598 // Map from the NodeId of a glob import to a list of items which are actually
6600 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
6602 impl<'tcx> AutoAdjustment<'tcx> {
6603 pub fn is_identity(&self) -> bool {
6605 AdjustReifyFnPointer |
6606 AdjustUnsafeFnPointer => false,
6607 AdjustDerefRef(ref r) => r.is_identity(),
6612 impl<'tcx> AutoDerefRef<'tcx> {
6613 pub fn is_identity(&self) -> bool {
6614 self.autoderefs == 0 && self.unsize.is_none() && self.autoref.is_none()
6618 impl<'tcx> ctxt<'tcx> {
6619 pub fn with_freevars<T, F>(&self, fid: ast::NodeId, f: F) -> T where
6620 F: FnOnce(&[Freevar]) -> T,
6622 match self.freevars.borrow().get(&fid) {
6624 Some(d) => f(&d[..])
6628 /// Replace any late-bound regions bound in `value` with free variants attached to scope-id
6630 pub fn liberate_late_bound_regions<T>(&self,
6631 all_outlive_scope: region::DestructionScopeData,
6634 where T : TypeFoldable<'tcx>
6636 ty_fold::replace_late_bound_regions(
6638 |br| ty::ReFree(ty::FreeRegion{scope: all_outlive_scope, bound_region: br})).0
6641 /// Flattens two binding levels into one. So `for<'a> for<'b> Foo`
6642 /// becomes `for<'a,'b> Foo`.
6643 pub fn flatten_late_bound_regions<T>(&self, bound2_value: &Binder<Binder<T>>)
6645 where T: TypeFoldable<'tcx>
6647 let bound0_value = bound2_value.skip_binder().skip_binder();
6648 let value = ty_fold::fold_regions(self, bound0_value, &mut false,
6649 |region, current_depth| {
6651 ty::ReLateBound(debruijn, br) if debruijn.depth >= current_depth => {
6652 // should be true if no escaping regions from bound2_value
6653 assert!(debruijn.depth - current_depth <= 1);
6654 ty::ReLateBound(DebruijnIndex::new(current_depth), br)
6664 pub fn no_late_bound_regions<T>(&self, value: &Binder<T>) -> Option<T>
6665 where T : TypeFoldable<'tcx> + RegionEscape
6667 if value.0.has_escaping_regions() {
6670 Some(value.0.clone())
6674 /// Replace any late-bound regions bound in `value` with `'static`. Useful in trans but also
6675 /// method lookup and a few other places where precise region relationships are not required.
6676 pub fn erase_late_bound_regions<T>(&self, value: &Binder<T>) -> T
6677 where T : TypeFoldable<'tcx>
6679 ty_fold::replace_late_bound_regions(self, value, |_| ty::ReStatic).0
6682 /// Rewrite any late-bound regions so that they are anonymous. Region numbers are
6683 /// assigned starting at 1 and increasing monotonically in the order traversed
6684 /// by the fold operation.
6686 /// The chief purpose of this function is to canonicalize regions so that two
6687 /// `FnSig`s or `TraitRef`s which are equivalent up to region naming will become
6688 /// structurally identical. For example, `for<'a, 'b> fn(&'a isize, &'b isize)` and
6689 /// `for<'a, 'b> fn(&'b isize, &'a isize)` will become identical after anonymization.
6690 pub fn anonymize_late_bound_regions<T>(&self, sig: &Binder<T>) -> Binder<T>
6691 where T : TypeFoldable<'tcx>,
6693 let mut counter = 0;
6694 ty::Binder(ty_fold::replace_late_bound_regions(self, sig, |_| {
6696 ReLateBound(ty::DebruijnIndex::new(1), BrAnon(counter))
6700 pub fn make_substs_for_receiver_types(&self,
6701 trait_ref: &ty::TraitRef<'tcx>,
6702 method: &ty::Method<'tcx>)
6703 -> subst::Substs<'tcx>
6706 * Substitutes the values for the receiver's type parameters
6707 * that are found in method, leaving the method's type parameters
6711 let meth_tps: Vec<Ty> =
6712 method.generics.types.get_slice(subst::FnSpace)
6714 .map(|def| self.mk_param_from_def(def))
6716 let meth_regions: Vec<ty::Region> =
6717 method.generics.regions.get_slice(subst::FnSpace)
6719 .map(|def| def.to_early_bound_region())
6721 trait_ref.substs.clone().with_method(meth_tps, meth_regions)
6725 impl DebruijnIndex {
6726 pub fn new(depth: u32) -> DebruijnIndex {
6728 DebruijnIndex { depth: depth }
6731 pub fn shifted(&self, amount: u32) -> DebruijnIndex {
6732 DebruijnIndex { depth: self.depth + amount }
6736 impl<'tcx> fmt::Debug for AutoAdjustment<'tcx> {
6737 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6739 AdjustReifyFnPointer => {
6740 write!(f, "AdjustReifyFnPointer")
6742 AdjustUnsafeFnPointer => {
6743 write!(f, "AdjustUnsafeFnPointer")
6745 AdjustDerefRef(ref data) => {
6746 write!(f, "{:?}", data)
6752 impl<'tcx> fmt::Debug for AutoDerefRef<'tcx> {
6753 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6754 write!(f, "AutoDerefRef({}, unsize={:?}, {:?})",
6755 self.autoderefs, self.unsize, self.autoref)
6759 impl<'tcx> fmt::Debug for TraitTy<'tcx> {
6760 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6761 write!(f, "TraitTy({:?},{:?})",
6767 impl<'tcx> fmt::Debug for ty::Predicate<'tcx> {
6768 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6770 Predicate::Trait(ref a) => write!(f, "{:?}", a),
6771 Predicate::Equate(ref pair) => write!(f, "{:?}", pair),
6772 Predicate::RegionOutlives(ref pair) => write!(f, "{:?}", pair),
6773 Predicate::TypeOutlives(ref pair) => write!(f, "{:?}", pair),
6774 Predicate::Projection(ref pair) => write!(f, "{:?}", pair),
6779 // FIXME(#20298) -- all of these traits basically walk various
6780 // structures to test whether types/regions are reachable with various
6781 // properties. It should be possible to express them in terms of one
6782 // common "walker" trait or something.
6784 /// An "escaping region" is a bound region whose binder is not part of `t`.
6786 /// So, for example, consider a type like the following, which has two binders:
6788 /// for<'a> fn(x: for<'b> fn(&'a isize, &'b isize))
6789 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ outer scope
6790 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ inner scope
6792 /// This type has *bound regions* (`'a`, `'b`), but it does not have escaping regions, because the
6793 /// binders of both `'a` and `'b` are part of the type itself. However, if we consider the *inner
6794 /// fn type*, that type has an escaping region: `'a`.
6796 /// Note that what I'm calling an "escaping region" is often just called a "free region". However,
6797 /// we already use the term "free region". It refers to the regions that we use to represent bound
6798 /// regions on a fn definition while we are typechecking its body.
6800 /// To clarify, conceptually there is no particular difference between an "escaping" region and a
6801 /// "free" region. However, there is a big difference in practice. Basically, when "entering" a
6802 /// binding level, one is generally required to do some sort of processing to a bound region, such
6803 /// as replacing it with a fresh/skolemized region, or making an entry in the environment to
6804 /// represent the scope to which it is attached, etc. An escaping region represents a bound region
6805 /// for which this processing has not yet been done.
6806 pub trait RegionEscape {
6807 fn has_escaping_regions(&self) -> bool {
6808 self.has_regions_escaping_depth(0)
6811 fn has_regions_escaping_depth(&self, depth: u32) -> bool;
6814 impl<'tcx> RegionEscape for Ty<'tcx> {
6815 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6816 self.region_depth > depth
6820 impl<'tcx> RegionEscape for Substs<'tcx> {
6821 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6822 self.types.has_regions_escaping_depth(depth) ||
6823 self.regions.has_regions_escaping_depth(depth)
6827 impl<'tcx> RegionEscape for ClosureSubsts<'tcx> {
6828 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6829 self.func_substs.has_regions_escaping_depth(depth) ||
6830 self.upvar_tys.iter().any(|t| t.has_regions_escaping_depth(depth))
6834 impl<T:RegionEscape> RegionEscape for Vec<T> {
6835 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6836 self.iter().any(|t| t.has_regions_escaping_depth(depth))
6840 impl<'tcx> RegionEscape for FnSig<'tcx> {
6841 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6842 self.inputs.has_regions_escaping_depth(depth) ||
6843 self.output.has_regions_escaping_depth(depth)
6847 impl<'tcx,T:RegionEscape> RegionEscape for VecPerParamSpace<T> {
6848 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6849 self.iter_enumerated().any(|(space, _, t)| {
6850 if space == subst::FnSpace {
6851 t.has_regions_escaping_depth(depth+1)
6853 t.has_regions_escaping_depth(depth)
6859 impl<'tcx> RegionEscape for TypeScheme<'tcx> {
6860 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6861 self.ty.has_regions_escaping_depth(depth)
6865 impl RegionEscape for Region {
6866 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6867 self.escapes_depth(depth)
6871 impl<'tcx> RegionEscape for GenericPredicates<'tcx> {
6872 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6873 self.predicates.has_regions_escaping_depth(depth)
6877 impl<'tcx> RegionEscape for Predicate<'tcx> {
6878 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6880 Predicate::Trait(ref data) => data.has_regions_escaping_depth(depth),
6881 Predicate::Equate(ref data) => data.has_regions_escaping_depth(depth),
6882 Predicate::RegionOutlives(ref data) => data.has_regions_escaping_depth(depth),
6883 Predicate::TypeOutlives(ref data) => data.has_regions_escaping_depth(depth),
6884 Predicate::Projection(ref data) => data.has_regions_escaping_depth(depth),
6889 impl<'tcx,P:RegionEscape> RegionEscape for traits::Obligation<'tcx,P> {
6890 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6891 self.predicate.has_regions_escaping_depth(depth)
6895 impl<'tcx> RegionEscape for TraitRef<'tcx> {
6896 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6897 self.substs.types.iter().any(|t| t.has_regions_escaping_depth(depth)) ||
6898 self.substs.regions.has_regions_escaping_depth(depth)
6902 impl<'tcx> RegionEscape for subst::RegionSubsts {
6903 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6905 subst::ErasedRegions => false,
6906 subst::NonerasedRegions(ref r) => {
6907 r.iter().any(|t| t.has_regions_escaping_depth(depth))
6913 impl<'tcx,T:RegionEscape> RegionEscape for Binder<T> {
6914 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6915 self.0.has_regions_escaping_depth(depth + 1)
6919 impl<'tcx> RegionEscape for FnOutput<'tcx> {
6920 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6922 FnConverging(t) => t.has_regions_escaping_depth(depth),
6923 FnDiverging => false
6928 impl<'tcx> RegionEscape for EquatePredicate<'tcx> {
6929 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6930 self.0.has_regions_escaping_depth(depth) || self.1.has_regions_escaping_depth(depth)
6934 impl<'tcx> RegionEscape for TraitPredicate<'tcx> {
6935 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6936 self.trait_ref.has_regions_escaping_depth(depth)
6940 impl<T:RegionEscape,U:RegionEscape> RegionEscape for OutlivesPredicate<T,U> {
6941 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6942 self.0.has_regions_escaping_depth(depth) || self.1.has_regions_escaping_depth(depth)
6946 impl<'tcx> RegionEscape for ProjectionPredicate<'tcx> {
6947 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6948 self.projection_ty.has_regions_escaping_depth(depth) ||
6949 self.ty.has_regions_escaping_depth(depth)
6953 impl<'tcx> RegionEscape for ProjectionTy<'tcx> {
6954 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6955 self.trait_ref.has_regions_escaping_depth(depth)
6959 pub trait HasTypeFlags {
6960 fn has_type_flags(&self, flags: TypeFlags) -> bool;
6961 fn has_projection_types(&self) -> bool {
6962 self.has_type_flags(TypeFlags::HAS_PROJECTION)
6964 fn references_error(&self) -> bool {
6965 self.has_type_flags(TypeFlags::HAS_TY_ERR)
6967 fn has_param_types(&self) -> bool {
6968 self.has_type_flags(TypeFlags::HAS_PARAMS)
6970 fn has_self_ty(&self) -> bool {
6971 self.has_type_flags(TypeFlags::HAS_SELF)
6973 fn has_infer_types(&self) -> bool {
6974 self.has_type_flags(TypeFlags::HAS_TY_INFER)
6976 fn needs_infer(&self) -> bool {
6977 self.has_type_flags(TypeFlags::HAS_TY_INFER | TypeFlags::HAS_RE_INFER)
6979 fn needs_subst(&self) -> bool {
6980 self.has_type_flags(TypeFlags::NEEDS_SUBST)
6982 fn has_closure_types(&self) -> bool {
6983 self.has_type_flags(TypeFlags::HAS_TY_CLOSURE)
6985 fn has_erasable_regions(&self) -> bool {
6986 self.has_type_flags(TypeFlags::HAS_RE_EARLY_BOUND |
6987 TypeFlags::HAS_RE_INFER |
6988 TypeFlags::HAS_FREE_REGIONS)
6990 /// Indicates whether this value references only 'global'
6991 /// types/lifetimes that are the same regardless of what fn we are
6992 /// in. This is used for caching. Errs on the side of returning
6994 fn is_global(&self) -> bool {
6995 !self.has_type_flags(TypeFlags::HAS_LOCAL_NAMES)
6999 impl<'tcx,T:HasTypeFlags> HasTypeFlags for Vec<T> {
7000 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7001 self[..].has_type_flags(flags)
7005 impl<'tcx,T:HasTypeFlags> HasTypeFlags for [T] {
7006 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7007 self.iter().any(|p| p.has_type_flags(flags))
7011 impl<'tcx,T:HasTypeFlags> HasTypeFlags for VecPerParamSpace<T> {
7012 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7013 self.iter().any(|p| p.has_type_flags(flags))
7017 impl<'tcx> HasTypeFlags for ClosureTy<'tcx> {
7018 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7019 self.sig.has_type_flags(flags)
7023 impl<'tcx> HasTypeFlags for ClosureUpvar<'tcx> {
7024 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7025 self.ty.has_type_flags(flags)
7029 impl<'tcx> HasTypeFlags for ty::InstantiatedPredicates<'tcx> {
7030 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7031 self.predicates.has_type_flags(flags)
7035 impl<'tcx> HasTypeFlags for Predicate<'tcx> {
7036 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7038 Predicate::Trait(ref data) => data.has_type_flags(flags),
7039 Predicate::Equate(ref data) => data.has_type_flags(flags),
7040 Predicate::RegionOutlives(ref data) => data.has_type_flags(flags),
7041 Predicate::TypeOutlives(ref data) => data.has_type_flags(flags),
7042 Predicate::Projection(ref data) => data.has_type_flags(flags),
7047 impl<'tcx> HasTypeFlags for TraitPredicate<'tcx> {
7048 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7049 self.trait_ref.has_type_flags(flags)
7053 impl<'tcx> HasTypeFlags for EquatePredicate<'tcx> {
7054 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7055 self.0.has_type_flags(flags) || self.1.has_type_flags(flags)
7059 impl HasTypeFlags for Region {
7060 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7061 if flags.intersects(TypeFlags::HAS_LOCAL_NAMES) {
7062 // does this represent a region that cannot be named in a global
7063 // way? used in fulfillment caching.
7065 ty::ReStatic | ty::ReEmpty => {}
7069 if flags.intersects(TypeFlags::HAS_RE_INFER) {
7070 if let ty::ReInfer(_) = *self {
7078 impl<T:HasTypeFlags,U:HasTypeFlags> HasTypeFlags for OutlivesPredicate<T,U> {
7079 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7080 self.0.has_type_flags(flags) || self.1.has_type_flags(flags)
7084 impl<'tcx> HasTypeFlags for ProjectionPredicate<'tcx> {
7085 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7086 self.projection_ty.has_type_flags(flags) || self.ty.has_type_flags(flags)
7090 impl<'tcx> HasTypeFlags for ProjectionTy<'tcx> {
7091 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7092 self.trait_ref.has_type_flags(flags)
7096 impl<'tcx> HasTypeFlags for Ty<'tcx> {
7097 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7098 self.flags.get().intersects(flags)
7102 impl<'tcx> HasTypeFlags for TraitRef<'tcx> {
7103 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7104 self.substs.has_type_flags(flags)
7108 impl<'tcx> HasTypeFlags for subst::Substs<'tcx> {
7109 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7110 self.types.has_type_flags(flags) || match self.regions {
7111 subst::ErasedRegions => false,
7112 subst::NonerasedRegions(ref r) => r.has_type_flags(flags)
7117 impl<'tcx,T> HasTypeFlags for Option<T>
7118 where T : HasTypeFlags
7120 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7121 self.iter().any(|t| t.has_type_flags(flags))
7125 impl<'tcx,T> HasTypeFlags for Rc<T>
7126 where T : HasTypeFlags
7128 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7129 (**self).has_type_flags(flags)
7133 impl<'tcx,T> HasTypeFlags for Box<T>
7134 where T : HasTypeFlags
7136 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7137 (**self).has_type_flags(flags)
7141 impl<T> HasTypeFlags for Binder<T>
7142 where T : HasTypeFlags
7144 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7145 self.0.has_type_flags(flags)
7149 impl<'tcx> HasTypeFlags for FnOutput<'tcx> {
7150 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7152 FnConverging(t) => t.has_type_flags(flags),
7153 FnDiverging => false,
7158 impl<'tcx> HasTypeFlags for FnSig<'tcx> {
7159 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7160 self.inputs.iter().any(|t| t.has_type_flags(flags)) ||
7161 self.output.has_type_flags(flags)
7165 impl<'tcx> HasTypeFlags for Field<'tcx> {
7166 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7167 self.mt.ty.has_type_flags(flags)
7171 impl<'tcx> HasTypeFlags for BareFnTy<'tcx> {
7172 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7173 self.sig.has_type_flags(flags)
7177 impl<'tcx> HasTypeFlags for ClosureSubsts<'tcx> {
7178 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7179 self.func_substs.has_type_flags(flags) ||
7180 self.upvar_tys.iter().any(|t| t.has_type_flags(flags))
7184 impl<'tcx> fmt::Debug for ClosureTy<'tcx> {
7185 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7186 write!(f, "ClosureTy({},{:?},{})",
7193 impl<'tcx> fmt::Debug for ClosureUpvar<'tcx> {
7194 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7195 write!(f, "ClosureUpvar({:?},{:?})",
7201 impl<'tcx> fmt::Debug for Field<'tcx> {
7202 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7203 write!(f, "field({},{})", self.name, self.mt)
7207 impl<'a, 'tcx> fmt::Debug for ParameterEnvironment<'a, 'tcx> {
7208 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7209 write!(f, "ParameterEnvironment(\
7211 implicit_region_bound={:?}, \
7212 caller_bounds={:?})",
7214 self.implicit_region_bound,
7219 impl<'tcx> fmt::Debug for ObjectLifetimeDefault {
7220 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7222 ObjectLifetimeDefault::Ambiguous => write!(f, "Ambiguous"),
7223 ObjectLifetimeDefault::BaseDefault => write!(f, "BaseDefault"),
7224 ObjectLifetimeDefault::Specific(ref r) => write!(f, "{:?}", r),