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;
58 use middle::region::RegionMaps;
59 use middle::stability;
60 use middle::subst::{self, ParamSpace, Subst, Substs, VecPerParamSpace};
63 use middle::ty_fold::{self, TypeFoldable, TypeFolder};
64 use middle::ty_walk::{self, TypeWalker};
65 use util::common::{memoized, ErrorReported};
66 use util::nodemap::{NodeMap, NodeSet, DefIdMap, DefIdSet};
67 use util::nodemap::FnvHashMap;
68 use util::num::ToPrimitive;
70 use arena::TypedArena;
71 use std::borrow::{Borrow, Cow};
72 use std::cell::{Cell, RefCell, Ref};
75 use std::hash::{Hash, SipHasher, Hasher};
79 use std::vec::IntoIter;
80 use collections::enum_set::{self, EnumSet, CLike};
81 use std::collections::{HashMap, HashSet};
83 use syntax::ast::{CrateNum, DefId, ItemImpl, ItemTrait, LOCAL_CRATE};
84 use syntax::ast::{MutImmutable, MutMutable, Name, NamedField, NodeId};
85 use syntax::ast::{StructField, UnnamedField, Visibility};
86 use syntax::ast_util::{self, is_local, local_def};
87 use syntax::attr::{self, AttrMetaMethods, SignedInt, UnsignedInt};
88 use syntax::codemap::Span;
89 use syntax::parse::token::{self, InternedString, special_idents};
90 use syntax::print::pprust;
96 pub const INITIAL_DISCRIMINANT_VALUE: Disr = 0;
100 /// The complete set of all analyses described in this module. This is
101 /// produced by the driver and fed to trans and later passes.
102 pub struct CrateAnalysis {
103 pub export_map: ExportMap,
104 pub exported_items: middle::privacy::ExportedItems,
105 pub public_items: middle::privacy::PublicItems,
106 pub reachable: NodeSet,
108 pub glob_map: Option<GlobMap>,
111 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
112 pub struct Field<'tcx> {
114 pub mt: TypeAndMut<'tcx>
121 pub struct VariantInfo<'tcx> {
122 pub args: Vec<Ty<'tcx>>,
123 pub arg_names: Option<Vec<ast::Name>>,
124 pub ctor_ty: Option<Ty<'tcx>>,
131 impl<'tcx> VariantInfo<'tcx> {
133 /// Creates a new VariantInfo from the corresponding ast representation.
135 /// Does not do any caching of the value in the type context.
136 pub fn from_ast_variant(cx: &ctxt<'tcx>,
137 ast_variant: &ast::Variant,
138 discriminant: Disr) -> VariantInfo<'tcx> {
139 let ctor_ty = cx.node_id_to_type(ast_variant.node.id);
141 match ast_variant.node.kind {
142 ast::TupleVariantKind(ref args) => {
143 let arg_tys = if !args.is_empty() {
144 // the regions in the argument types come from the
145 // enum def'n, and hence will all be early bound
146 cx.no_late_bound_regions(&ctor_ty.fn_args()).unwrap()
154 ctor_ty: Some(ctor_ty),
155 name: ast_variant.node.name.name,
156 id: ast_util::local_def(ast_variant.node.id),
157 disr_val: discriminant,
158 vis: ast_variant.node.vis
161 ast::StructVariantKind(ref struct_def) => {
162 let fields: &[StructField] = &struct_def.fields;
164 assert!(!fields.is_empty());
166 let arg_tys = struct_def.fields.iter()
167 .map(|field| cx.node_id_to_type(field.node.id)).collect();
168 let arg_names = fields.iter().map(|field| {
169 match field.node.kind {
170 NamedField(ident, _) => ident.name,
171 UnnamedField(..) => cx.sess.bug(
172 "enum_variants: all fields in struct must have a name")
178 arg_names: Some(arg_names),
180 name: ast_variant.node.name.name,
181 id: ast_util::local_def(ast_variant.node.id),
182 disr_val: discriminant,
183 vis: ast_variant.node.vis
190 #[derive(Copy, Clone)]
193 TraitDtor(DefId, bool)
197 pub fn is_present(&self) -> bool {
199 TraitDtor(..) => true,
204 pub fn has_drop_flag(&self) -> bool {
207 &TraitDtor(_, flag) => flag
213 fn to_ty<'tcx>(&self, cx: &ctxt<'tcx>) -> Ty<'tcx>;
214 fn i64_to_disr(&self, val: i64) -> Option<Disr>;
215 fn u64_to_disr(&self, val: u64) -> Option<Disr>;
216 fn disr_incr(&self, val: Disr) -> Option<Disr>;
217 fn disr_string(&self, val: Disr) -> String;
218 fn disr_wrap_incr(&self, val: Option<Disr>) -> Disr;
221 impl IntTypeExt for attr::IntType {
222 fn to_ty<'tcx>(&self, cx: &ctxt<'tcx>) -> Ty<'tcx> {
224 SignedInt(ast::TyI8) => cx.types.i8,
225 SignedInt(ast::TyI16) => cx.types.i16,
226 SignedInt(ast::TyI32) => cx.types.i32,
227 SignedInt(ast::TyI64) => cx.types.i64,
228 SignedInt(ast::TyIs) => cx.types.isize,
229 UnsignedInt(ast::TyU8) => cx.types.u8,
230 UnsignedInt(ast::TyU16) => cx.types.u16,
231 UnsignedInt(ast::TyU32) => cx.types.u32,
232 UnsignedInt(ast::TyU64) => cx.types.u64,
233 UnsignedInt(ast::TyUs) => cx.types.usize,
237 fn i64_to_disr(&self, val: i64) -> Option<Disr> {
239 SignedInt(ast::TyI8) => val.to_i8() .map(|v| v as Disr),
240 SignedInt(ast::TyI16) => val.to_i16() .map(|v| v as Disr),
241 SignedInt(ast::TyI32) => val.to_i32() .map(|v| v as Disr),
242 SignedInt(ast::TyI64) => val.to_i64() .map(|v| v as Disr),
243 UnsignedInt(ast::TyU8) => val.to_u8() .map(|v| v as Disr),
244 UnsignedInt(ast::TyU16) => val.to_u16() .map(|v| v as Disr),
245 UnsignedInt(ast::TyU32) => val.to_u32() .map(|v| v as Disr),
246 UnsignedInt(ast::TyU64) => val.to_u64() .map(|v| v as Disr),
248 UnsignedInt(ast::TyUs) |
249 SignedInt(ast::TyIs) => unreachable!(),
253 fn u64_to_disr(&self, val: u64) -> Option<Disr> {
255 SignedInt(ast::TyI8) => val.to_i8() .map(|v| v as Disr),
256 SignedInt(ast::TyI16) => val.to_i16() .map(|v| v as Disr),
257 SignedInt(ast::TyI32) => val.to_i32() .map(|v| v as Disr),
258 SignedInt(ast::TyI64) => val.to_i64() .map(|v| v as Disr),
259 UnsignedInt(ast::TyU8) => val.to_u8() .map(|v| v as Disr),
260 UnsignedInt(ast::TyU16) => val.to_u16() .map(|v| v as Disr),
261 UnsignedInt(ast::TyU32) => val.to_u32() .map(|v| v as Disr),
262 UnsignedInt(ast::TyU64) => val.to_u64() .map(|v| v as Disr),
264 UnsignedInt(ast::TyUs) |
265 SignedInt(ast::TyIs) => unreachable!(),
269 fn disr_incr(&self, val: Disr) -> Option<Disr> {
271 ($e:expr) => { $e.and_then(|v|v.checked_add(1)).map(|v| v as Disr) }
274 // SignedInt repr means we *want* to reinterpret the bits
275 // treating the highest bit of Disr as a sign-bit, so
276 // cast to i64 before range-checking.
277 SignedInt(ast::TyI8) => add1!((val as i64).to_i8()),
278 SignedInt(ast::TyI16) => add1!((val as i64).to_i16()),
279 SignedInt(ast::TyI32) => add1!((val as i64).to_i32()),
280 SignedInt(ast::TyI64) => add1!(Some(val as i64)),
282 UnsignedInt(ast::TyU8) => add1!(val.to_u8()),
283 UnsignedInt(ast::TyU16) => add1!(val.to_u16()),
284 UnsignedInt(ast::TyU32) => add1!(val.to_u32()),
285 UnsignedInt(ast::TyU64) => add1!(Some(val)),
287 UnsignedInt(ast::TyUs) |
288 SignedInt(ast::TyIs) => unreachable!(),
292 // This returns a String because (1.) it is only used for
293 // rendering an error message and (2.) a string can represent the
294 // full range from `i64::MIN` through `u64::MAX`.
295 fn disr_string(&self, val: Disr) -> String {
297 SignedInt(ast::TyI8) => format!("{}", val as i8 ),
298 SignedInt(ast::TyI16) => format!("{}", val as i16),
299 SignedInt(ast::TyI32) => format!("{}", val as i32),
300 SignedInt(ast::TyI64) => format!("{}", val as i64),
301 UnsignedInt(ast::TyU8) => format!("{}", val as u8 ),
302 UnsignedInt(ast::TyU16) => format!("{}", val as u16),
303 UnsignedInt(ast::TyU32) => format!("{}", val as u32),
304 UnsignedInt(ast::TyU64) => format!("{}", val as u64),
306 UnsignedInt(ast::TyUs) |
307 SignedInt(ast::TyIs) => unreachable!(),
311 fn disr_wrap_incr(&self, val: Option<Disr>) -> Disr {
313 ($e:expr) => { ($e).wrapping_add(1) as Disr }
315 let val = val.unwrap_or(ty::INITIAL_DISCRIMINANT_VALUE);
317 SignedInt(ast::TyI8) => add1!(val as i8 ),
318 SignedInt(ast::TyI16) => add1!(val as i16),
319 SignedInt(ast::TyI32) => add1!(val as i32),
320 SignedInt(ast::TyI64) => add1!(val as i64),
321 UnsignedInt(ast::TyU8) => add1!(val as u8 ),
322 UnsignedInt(ast::TyU16) => add1!(val as u16),
323 UnsignedInt(ast::TyU32) => add1!(val as u32),
324 UnsignedInt(ast::TyU64) => add1!(val as u64),
326 UnsignedInt(ast::TyUs) |
327 SignedInt(ast::TyIs) => unreachable!(),
332 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
333 pub enum ImplOrTraitItemContainer {
334 TraitContainer(ast::DefId),
335 ImplContainer(ast::DefId),
338 impl ImplOrTraitItemContainer {
339 pub fn id(&self) -> ast::DefId {
341 TraitContainer(id) => id,
342 ImplContainer(id) => id,
348 pub enum ImplOrTraitItem<'tcx> {
349 ConstTraitItem(Rc<AssociatedConst<'tcx>>),
350 MethodTraitItem(Rc<Method<'tcx>>),
351 TypeTraitItem(Rc<AssociatedType<'tcx>>),
354 impl<'tcx> ImplOrTraitItem<'tcx> {
355 fn id(&self) -> ImplOrTraitItemId {
357 ConstTraitItem(ref associated_const) => {
358 ConstTraitItemId(associated_const.def_id)
360 MethodTraitItem(ref method) => MethodTraitItemId(method.def_id),
361 TypeTraitItem(ref associated_type) => {
362 TypeTraitItemId(associated_type.def_id)
367 pub fn def_id(&self) -> ast::DefId {
369 ConstTraitItem(ref associated_const) => associated_const.def_id,
370 MethodTraitItem(ref method) => method.def_id,
371 TypeTraitItem(ref associated_type) => associated_type.def_id,
375 pub fn name(&self) -> ast::Name {
377 ConstTraitItem(ref associated_const) => associated_const.name,
378 MethodTraitItem(ref method) => method.name,
379 TypeTraitItem(ref associated_type) => associated_type.name,
383 pub fn vis(&self) -> ast::Visibility {
385 ConstTraitItem(ref associated_const) => associated_const.vis,
386 MethodTraitItem(ref method) => method.vis,
387 TypeTraitItem(ref associated_type) => associated_type.vis,
391 pub fn container(&self) -> ImplOrTraitItemContainer {
393 ConstTraitItem(ref associated_const) => associated_const.container,
394 MethodTraitItem(ref method) => method.container,
395 TypeTraitItem(ref associated_type) => associated_type.container,
399 pub fn as_opt_method(&self) -> Option<Rc<Method<'tcx>>> {
401 MethodTraitItem(ref m) => Some((*m).clone()),
407 #[derive(Clone, Copy, Debug)]
408 pub enum ImplOrTraitItemId {
409 ConstTraitItemId(ast::DefId),
410 MethodTraitItemId(ast::DefId),
411 TypeTraitItemId(ast::DefId),
414 impl ImplOrTraitItemId {
415 pub fn def_id(&self) -> ast::DefId {
417 ConstTraitItemId(def_id) => def_id,
418 MethodTraitItemId(def_id) => def_id,
419 TypeTraitItemId(def_id) => def_id,
424 #[derive(Clone, Debug)]
425 pub struct Method<'tcx> {
427 pub generics: Generics<'tcx>,
428 pub predicates: GenericPredicates<'tcx>,
429 pub fty: BareFnTy<'tcx>,
430 pub explicit_self: ExplicitSelfCategory,
431 pub vis: ast::Visibility,
432 pub def_id: ast::DefId,
433 pub container: ImplOrTraitItemContainer,
435 // If this method is provided, we need to know where it came from
436 pub provided_source: Option<ast::DefId>
439 impl<'tcx> Method<'tcx> {
440 pub fn new(name: ast::Name,
441 generics: ty::Generics<'tcx>,
442 predicates: GenericPredicates<'tcx>,
444 explicit_self: ExplicitSelfCategory,
445 vis: ast::Visibility,
447 container: ImplOrTraitItemContainer,
448 provided_source: Option<ast::DefId>)
453 predicates: predicates,
455 explicit_self: explicit_self,
458 container: container,
459 provided_source: provided_source
463 pub fn container_id(&self) -> ast::DefId {
464 match self.container {
465 TraitContainer(id) => id,
466 ImplContainer(id) => id,
471 #[derive(Clone, Copy, Debug)]
472 pub struct AssociatedConst<'tcx> {
475 pub vis: ast::Visibility,
476 pub def_id: ast::DefId,
477 pub container: ImplOrTraitItemContainer,
478 pub default: Option<ast::DefId>,
481 #[derive(Clone, Copy, Debug)]
482 pub struct AssociatedType<'tcx> {
484 pub ty: Option<Ty<'tcx>>,
485 pub vis: ast::Visibility,
486 pub def_id: ast::DefId,
487 pub container: ImplOrTraitItemContainer,
490 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
491 pub struct TypeAndMut<'tcx> {
493 pub mutbl: ast::Mutability,
496 #[derive(Clone, Copy, Debug)]
500 pub vis: ast::Visibility,
501 pub origin: ast::DefId, // The DefId of the struct in which the field is declared.
504 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable)]
505 pub struct ItemVariances {
506 pub types: VecPerParamSpace<Variance>,
507 pub regions: VecPerParamSpace<Variance>,
510 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
512 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
513 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
514 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
515 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
518 impl fmt::Debug for Variance {
519 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
520 f.write_str(match *self {
522 Contravariant => "-",
529 #[derive(Copy, Clone)]
530 pub enum AutoAdjustment<'tcx> {
531 AdjustReifyFnPointer, // go from a fn-item type to a fn-pointer type
532 AdjustUnsafeFnPointer, // go from a safe fn pointer to an unsafe fn pointer
533 AdjustDerefRef(AutoDerefRef<'tcx>),
536 /// Represents coercing a pointer to a different kind of pointer - where 'kind'
537 /// here means either or both of raw vs borrowed vs unique and fat vs thin.
539 /// We transform pointers by following the following steps in order:
540 /// 1. Deref the pointer `self.autoderefs` times (may be 0).
541 /// 2. If `autoref` is `Some(_)`, then take the address and produce either a
542 /// `&` or `*` pointer.
543 /// 3. If `unsize` is `Some(_)`, then apply the unsize transformation,
544 /// which will do things like convert thin pointers to fat
545 /// pointers, or convert structs containing thin pointers to
546 /// structs containing fat pointers, or convert between fat
547 /// pointers. We don't store the details of how the transform is
548 /// done (in fact, we don't know that, because it might depend on
549 /// the precise type parameters). We just store the target
550 /// type. Trans figures out what has to be done at monomorphization
551 /// time based on the precise source/target type at hand.
553 /// To make that more concrete, here are some common scenarios:
555 /// 1. The simplest cases are where the pointer is not adjusted fat vs thin.
556 /// Here the pointer will be dereferenced N times (where a dereference can
557 /// happen to to raw or borrowed pointers or any smart pointer which implements
558 /// Deref, including Box<_>). The number of dereferences is given by
559 /// `autoderefs`. It can then be auto-referenced zero or one times, indicated
560 /// by `autoref`, to either a raw or borrowed pointer. In these cases unsize is
563 /// 2. A thin-to-fat coercon involves unsizing the underlying data. We start
564 /// with a thin pointer, deref a number of times, unsize the underlying data,
565 /// then autoref. The 'unsize' phase may change a fixed length array to a
566 /// dynamically sized one, a concrete object to a trait object, or statically
567 /// sized struct to a dyncamically sized one. E.g., &[i32; 4] -> &[i32] is
572 /// autoderefs: 1, // &[i32; 4] -> [i32; 4]
573 /// autoref: Some(AutoPtr), // [i32] -> &[i32]
574 /// unsize: Some([i32]), // [i32; 4] -> [i32]
578 /// Note that for a struct, the 'deep' unsizing of the struct is not recorded.
579 /// E.g., `struct Foo<T> { x: T }` we can coerce &Foo<[i32; 4]> to &Foo<[i32]>
580 /// The autoderef and -ref are the same as in the above example, but the type
581 /// stored in `unsize` is `Foo<[i32]>`, we don't store any further detail about
582 /// the underlying conversions from `[i32; 4]` to `[i32]`.
584 /// 3. Coercing a `Box<T>` to `Box<Trait>` is an interesting special case. In
585 /// that case, we have the pointer we need coming in, so there are no
586 /// autoderefs, and no autoref. Instead we just do the `Unsize` transformation.
587 /// At some point, of course, `Box` should move out of the compiler, in which
588 /// case this is analogous to transformating a struct. E.g., Box<[i32; 4]> ->
589 /// Box<[i32]> is represented by:
595 /// unsize: Some(Box<[i32]>),
598 #[derive(Copy, Clone)]
599 pub struct AutoDerefRef<'tcx> {
600 /// Step 1. Apply a number of dereferences, producing an lvalue.
601 pub autoderefs: usize,
603 /// Step 2. Optionally produce a pointer/reference from the value.
604 pub autoref: Option<AutoRef<'tcx>>,
606 /// Step 3. Unsize a pointer/reference value, e.g. `&[T; n]` to
607 /// `&[T]`. The stored type is the target pointer type. Note that
608 /// the source could be a thin or fat pointer.
609 pub unsize: Option<Ty<'tcx>>,
612 #[derive(Copy, Clone, PartialEq, Debug)]
613 pub enum AutoRef<'tcx> {
614 /// Convert from T to &T.
615 AutoPtr(&'tcx Region, ast::Mutability),
617 /// Convert from T to *T.
618 /// Value to thin pointer.
619 AutoUnsafe(ast::Mutability),
622 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)]
623 pub enum CustomCoerceUnsized {
624 /// Records the index of the field being coerced.
628 #[derive(Clone, Copy, Debug)]
629 pub struct MethodCallee<'tcx> {
630 /// Impl method ID, for inherent methods, or trait method ID, otherwise.
631 pub def_id: ast::DefId,
633 pub substs: &'tcx subst::Substs<'tcx>
636 /// With method calls, we store some extra information in
637 /// side tables (i.e method_map). We use
638 /// MethodCall as a key to index into these tables instead of
639 /// just directly using the expression's NodeId. The reason
640 /// for this being that we may apply adjustments (coercions)
641 /// with the resulting expression also needing to use the
642 /// side tables. The problem with this is that we don't
643 /// assign a separate NodeId to this new expression
644 /// and so it would clash with the base expression if both
645 /// needed to add to the side tables. Thus to disambiguate
646 /// we also keep track of whether there's an adjustment in
648 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
649 pub struct MethodCall {
650 pub expr_id: ast::NodeId,
655 pub fn expr(id: ast::NodeId) -> MethodCall {
662 pub fn autoderef(expr_id: ast::NodeId, autoderef: u32) -> MethodCall {
665 autoderef: 1 + autoderef
670 // maps from an expression id that corresponds to a method call to the details
671 // of the method to be invoked
672 pub type MethodMap<'tcx> = FnvHashMap<MethodCall, MethodCallee<'tcx>>;
674 // Contains information needed to resolve types and (in the future) look up
675 // the types of AST nodes.
676 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
677 pub struct CReaderCacheKey {
683 /// A restriction that certain types must be the same size. The use of
684 /// `transmute` gives rise to these restrictions. These generally
685 /// cannot be checked until trans; therefore, each call to `transmute`
686 /// will push one or more such restriction into the
687 /// `transmute_restrictions` vector during `intrinsicck`. They are
688 /// then checked during `trans` by the fn `check_intrinsics`.
689 #[derive(Copy, Clone)]
690 pub struct TransmuteRestriction<'tcx> {
691 /// The span whence the restriction comes.
694 /// The type being transmuted from.
695 pub original_from: Ty<'tcx>,
697 /// The type being transmuted to.
698 pub original_to: Ty<'tcx>,
700 /// The type being transmuted from, with all type parameters
701 /// substituted for an arbitrary representative. Not to be shown
703 pub substituted_from: Ty<'tcx>,
705 /// The type being transmuted to, with all type parameters
706 /// substituted for an arbitrary representative. Not to be shown
708 pub substituted_to: Ty<'tcx>,
710 /// NodeId of the transmute intrinsic.
715 pub struct CtxtArenas<'tcx> {
717 type_: TypedArena<TyS<'tcx>>,
718 substs: TypedArena<Substs<'tcx>>,
719 bare_fn: TypedArena<BareFnTy<'tcx>>,
720 region: TypedArena<Region>,
721 stability: TypedArena<attr::Stability>,
724 trait_defs: TypedArena<TraitDef<'tcx>>,
727 impl<'tcx> CtxtArenas<'tcx> {
728 pub fn new() -> CtxtArenas<'tcx> {
730 type_: TypedArena::new(),
731 substs: TypedArena::new(),
732 bare_fn: TypedArena::new(),
733 region: TypedArena::new(),
734 stability: TypedArena::new(),
736 trait_defs: TypedArena::new()
741 pub struct CommonTypes<'tcx> {
759 pub struct Tables<'tcx> {
760 /// Stores the types for various nodes in the AST. Note that this table
761 /// is not guaranteed to be populated until after typeck. See
762 /// typeck::check::fn_ctxt for details.
763 pub node_types: NodeMap<Ty<'tcx>>,
765 /// Stores the type parameters which were substituted to obtain the type
766 /// of this node. This only applies to nodes that refer to entities
767 /// parameterized by type parameters, such as generic fns, types, or
769 pub item_substs: NodeMap<ItemSubsts<'tcx>>,
771 pub adjustments: NodeMap<ty::AutoAdjustment<'tcx>>,
773 pub method_map: MethodMap<'tcx>,
776 pub upvar_capture_map: UpvarCaptureMap,
778 /// Records the type of each closure. The def ID is the ID of the
779 /// expression defining the closure.
780 pub closure_tys: DefIdMap<ClosureTy<'tcx>>,
782 /// Records the type of each closure. The def ID is the ID of the
783 /// expression defining the closure.
784 pub closure_kinds: DefIdMap<ClosureKind>,
787 impl<'tcx> Tables<'tcx> {
788 pub fn empty() -> Tables<'tcx> {
790 node_types: FnvHashMap(),
791 item_substs: NodeMap(),
792 adjustments: NodeMap(),
793 method_map: FnvHashMap(),
794 upvar_capture_map: FnvHashMap(),
795 closure_tys: DefIdMap(),
796 closure_kinds: DefIdMap(),
801 /// The data structure to keep track of all the information that typechecker
802 /// generates so that so that it can be reused and doesn't have to be redone
804 pub struct ctxt<'tcx> {
805 /// The arenas that types etc are allocated from.
806 arenas: &'tcx CtxtArenas<'tcx>,
808 /// Specifically use a speedy hash algorithm for this hash map, it's used
810 // FIXME(eddyb) use a FnvHashSet<InternedTy<'tcx>> when equivalent keys can
811 // queried from a HashSet.
812 interner: RefCell<FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>>,
814 // FIXME as above, use a hashset if equivalent elements can be queried.
815 substs_interner: RefCell<FnvHashMap<&'tcx Substs<'tcx>, &'tcx Substs<'tcx>>>,
816 bare_fn_interner: RefCell<FnvHashMap<&'tcx BareFnTy<'tcx>, &'tcx BareFnTy<'tcx>>>,
817 region_interner: RefCell<FnvHashMap<&'tcx Region, &'tcx Region>>,
818 stability_interner: RefCell<FnvHashMap<&'tcx attr::Stability, &'tcx attr::Stability>>,
820 /// Common types, pre-interned for your convenience.
821 pub types: CommonTypes<'tcx>,
826 pub named_region_map: resolve_lifetime::NamedRegionMap,
828 pub region_maps: RegionMaps,
830 // For each fn declared in the local crate, type check stores the
831 // free-region relationships that were deduced from its where
832 // clauses and parameter types. These are then read-again by
833 // borrowck. (They are not used during trans, and hence are not
834 // serialized or needed for cross-crate fns.)
835 free_region_maps: RefCell<NodeMap<FreeRegionMap>>,
836 // FIXME: jroesch make this a refcell
838 pub tables: RefCell<Tables<'tcx>>,
840 /// Maps from a trait item to the trait item "descriptor"
841 pub impl_or_trait_items: RefCell<DefIdMap<ImplOrTraitItem<'tcx>>>,
843 /// Maps from a trait def-id to a list of the def-ids of its trait items
844 pub trait_item_def_ids: RefCell<DefIdMap<Rc<Vec<ImplOrTraitItemId>>>>,
846 /// A cache for the trait_items() routine
847 pub trait_items_cache: RefCell<DefIdMap<Rc<Vec<ImplOrTraitItem<'tcx>>>>>,
849 pub impl_trait_refs: RefCell<DefIdMap<Option<TraitRef<'tcx>>>>,
850 pub trait_defs: RefCell<DefIdMap<&'tcx TraitDef<'tcx>>>,
852 /// Maps from the def-id of an item (trait/struct/enum/fn) to its
853 /// associated predicates.
854 pub predicates: RefCell<DefIdMap<GenericPredicates<'tcx>>>,
856 /// Maps from the def-id of a trait to the list of
857 /// super-predicates. This is a subset of the full list of
858 /// predicates. We store these in a separate map because we must
859 /// evaluate them even during type conversion, often before the
860 /// full predicates are available (note that supertraits have
861 /// additional acyclicity requirements).
862 pub super_predicates: RefCell<DefIdMap<GenericPredicates<'tcx>>>,
864 pub map: ast_map::Map<'tcx>,
865 pub freevars: RefCell<FreevarMap>,
866 pub tcache: RefCell<DefIdMap<TypeScheme<'tcx>>>,
867 pub rcache: RefCell<FnvHashMap<CReaderCacheKey, Ty<'tcx>>>,
868 pub tc_cache: RefCell<FnvHashMap<Ty<'tcx>, TypeContents>>,
869 pub ast_ty_to_ty_cache: RefCell<NodeMap<Ty<'tcx>>>,
870 pub enum_var_cache: RefCell<DefIdMap<Rc<Vec<Rc<VariantInfo<'tcx>>>>>>,
871 pub ty_param_defs: RefCell<NodeMap<TypeParameterDef<'tcx>>>,
872 pub normalized_cache: RefCell<FnvHashMap<Ty<'tcx>, Ty<'tcx>>>,
873 pub lang_items: middle::lang_items::LanguageItems,
874 /// A mapping of fake provided method def_ids to the default implementation
875 pub provided_method_sources: RefCell<DefIdMap<ast::DefId>>,
876 pub struct_fields: RefCell<DefIdMap<Rc<Vec<FieldTy>>>>,
878 /// Maps from def-id of a type or region parameter to its
879 /// (inferred) variance.
880 pub item_variance_map: RefCell<DefIdMap<Rc<ItemVariances>>>,
882 /// True if the variance has been computed yet; false otherwise.
883 pub variance_computed: Cell<bool>,
885 /// A mapping from the def ID of an enum or struct type to the def ID
886 /// of the method that implements its destructor. If the type is not
887 /// present in this map, it does not have a destructor. This map is
888 /// populated during the coherence phase of typechecking.
889 pub destructor_for_type: RefCell<DefIdMap<ast::DefId>>,
891 /// A method will be in this list if and only if it is a destructor.
892 pub destructors: RefCell<DefIdSet>,
894 /// Maps a DefId of a type to a list of its inherent impls.
895 /// Contains implementations of methods that are inherent to a type.
896 /// Methods in these implementations don't need to be exported.
897 pub inherent_impls: RefCell<DefIdMap<Rc<Vec<ast::DefId>>>>,
899 /// Maps a DefId of an impl to a list of its items.
900 /// Note that this contains all of the impls that we know about,
901 /// including ones in other crates. It's not clear that this is the best
903 pub impl_items: RefCell<DefIdMap<Vec<ImplOrTraitItemId>>>,
905 /// Set of used unsafe nodes (functions or blocks). Unsafe nodes not
906 /// present in this set can be warned about.
907 pub used_unsafe: RefCell<NodeSet>,
909 /// Set of nodes which mark locals as mutable which end up getting used at
910 /// some point. Local variable definitions not in this set can be warned
912 pub used_mut_nodes: RefCell<NodeSet>,
914 /// The set of external nominal types whose implementations have been read.
915 /// This is used for lazy resolution of methods.
916 pub populated_external_types: RefCell<DefIdSet>,
917 /// The set of external primitive types whose implementations have been read.
918 /// FIXME(arielb1): why is this separate from populated_external_types?
919 pub populated_external_primitive_impls: RefCell<DefIdSet>,
921 /// These caches are used by const_eval when decoding external constants.
922 pub extern_const_statics: RefCell<DefIdMap<ast::NodeId>>,
923 pub extern_const_variants: RefCell<DefIdMap<ast::NodeId>>,
924 pub extern_const_fns: RefCell<DefIdMap<ast::NodeId>>,
926 pub dependency_formats: RefCell<dependency_format::Dependencies>,
928 pub node_lint_levels: RefCell<FnvHashMap<(ast::NodeId, lint::LintId),
931 /// The types that must be asserted to be the same size for `transmute`
932 /// to be valid. We gather up these restrictions in the intrinsicck pass
933 /// and check them in trans.
934 pub transmute_restrictions: RefCell<Vec<TransmuteRestriction<'tcx>>>,
936 /// Maps any item's def-id to its stability index.
937 pub stability: RefCell<stability::Index<'tcx>>,
939 /// Caches the results of trait selection. This cache is used
940 /// for things that do not have to do with the parameters in scope.
941 pub selection_cache: traits::SelectionCache<'tcx>,
943 /// A set of predicates that have been fulfilled *somewhere*.
944 /// This is used to avoid duplicate work. Predicates are only
945 /// added to this set when they mention only "global" names
946 /// (i.e., no type or lifetime parameters).
947 pub fulfilled_predicates: RefCell<traits::FulfilledPredicates<'tcx>>,
949 /// Caches the representation hints for struct definitions.
950 pub repr_hint_cache: RefCell<DefIdMap<Rc<Vec<attr::ReprAttr>>>>,
952 /// Maps Expr NodeId's to their constant qualification.
953 pub const_qualif_map: RefCell<NodeMap<check_const::ConstQualif>>,
955 /// Caches CoerceUnsized kinds for impls on custom types.
956 pub custom_coerce_unsized_kinds: RefCell<DefIdMap<CustomCoerceUnsized>>,
958 /// Maps a cast expression to its kind. This is keyed on the
959 /// *from* expression of the cast, not the cast itself.
960 pub cast_kinds: RefCell<NodeMap<cast::CastKind>>,
963 impl<'tcx> ctxt<'tcx> {
964 pub fn node_types(&self) -> Ref<NodeMap<Ty<'tcx>>> {
965 fn projection<'a, 'tcx>(tables: &'a Tables<'tcx>) -> &'a NodeMap<Ty<'tcx>> {
969 Ref::map(self.tables.borrow(), projection)
972 pub fn node_type_insert(&self, id: NodeId, ty: Ty<'tcx>) {
973 self.tables.borrow_mut().node_types.insert(id, ty);
976 pub fn intern_trait_def(&self, def: TraitDef<'tcx>) -> &'tcx TraitDef<'tcx> {
977 let did = def.trait_ref.def_id;
978 let interned = self.arenas.trait_defs.alloc(def);
979 self.trait_defs.borrow_mut().insert(did, interned);
983 pub fn intern_stability(&self, stab: attr::Stability) -> &'tcx attr::Stability {
984 if let Some(st) = self.stability_interner.borrow().get(&stab) {
988 let interned = self.arenas.stability.alloc(stab);
989 self.stability_interner.borrow_mut().insert(interned, interned);
993 pub fn store_free_region_map(&self, id: NodeId, map: FreeRegionMap) {
994 self.free_region_maps.borrow_mut()
998 pub fn free_region_map(&self, id: NodeId) -> FreeRegionMap {
999 self.free_region_maps.borrow()[&id].clone()
1002 pub fn lift<T: ?Sized + Lift<'tcx>>(&self, value: &T) -> Option<T::Lifted> {
1003 value.lift_to_tcx(self)
1007 /// A trait implemented for all X<'a> types which can be safely and
1008 /// efficiently converted to X<'tcx> as long as they are part of the
1009 /// provided ty::ctxt<'tcx>.
1010 /// This can be done, for example, for Ty<'tcx> or &'tcx Substs<'tcx>
1011 /// by looking them up in their respective interners.
1012 /// None is returned if the value or one of the components is not part
1013 /// of the provided context.
1014 /// For Ty, None can be returned if either the type interner doesn't
1015 /// contain the TypeVariants key or if the address of the interned
1016 /// pointer differs. The latter case is possible if a primitive type,
1017 /// e.g. `()` or `u8`, was interned in a different context.
1018 pub trait Lift<'tcx> {
1020 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted>;
1023 impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>> Lift<'tcx> for (A, B) {
1024 type Lifted = (A::Lifted, B::Lifted);
1025 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1026 tcx.lift(&self.0).and_then(|a| tcx.lift(&self.1).map(|b| (a, b)))
1030 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for [T] {
1031 type Lifted = Vec<T::Lifted>;
1032 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1033 let mut result = Vec::with_capacity(self.len());
1035 if let Some(value) = tcx.lift(x) {
1045 impl<'tcx> Lift<'tcx> for Region {
1047 fn lift_to_tcx(&self, _: &ctxt<'tcx>) -> Option<Region> {
1052 impl<'a, 'tcx> Lift<'tcx> for Ty<'a> {
1053 type Lifted = Ty<'tcx>;
1054 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Ty<'tcx>> {
1055 if let Some(&ty) = tcx.interner.borrow().get(&self.sty) {
1056 if *self as *const _ == ty as *const _ {
1064 impl<'a, 'tcx> Lift<'tcx> for &'a Substs<'a> {
1065 type Lifted = &'tcx Substs<'tcx>;
1066 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<&'tcx Substs<'tcx>> {
1067 if let Some(&substs) = tcx.substs_interner.borrow().get(*self) {
1068 if *self as *const _ == substs as *const _ {
1069 return Some(substs);
1076 impl<'a, 'tcx> Lift<'tcx> for TraitRef<'a> {
1077 type Lifted = TraitRef<'tcx>;
1078 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<TraitRef<'tcx>> {
1079 tcx.lift(&self.substs).map(|substs| TraitRef {
1080 def_id: self.def_id,
1086 impl<'a, 'tcx> Lift<'tcx> for TraitPredicate<'a> {
1087 type Lifted = TraitPredicate<'tcx>;
1088 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<TraitPredicate<'tcx>> {
1089 tcx.lift(&self.trait_ref).map(|trait_ref| TraitPredicate {
1090 trait_ref: trait_ref
1095 impl<'a, 'tcx> Lift<'tcx> for EquatePredicate<'a> {
1096 type Lifted = EquatePredicate<'tcx>;
1097 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<EquatePredicate<'tcx>> {
1098 tcx.lift(&(self.0, self.1)).map(|(a, b)| EquatePredicate(a, b))
1102 impl<'tcx, A: Copy+Lift<'tcx>, B: Copy+Lift<'tcx>> Lift<'tcx> for OutlivesPredicate<A, B> {
1103 type Lifted = OutlivesPredicate<A::Lifted, B::Lifted>;
1104 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1105 tcx.lift(&(self.0, self.1)).map(|(a, b)| OutlivesPredicate(a, b))
1109 impl<'a, 'tcx> Lift<'tcx> for ProjectionPredicate<'a> {
1110 type Lifted = ProjectionPredicate<'tcx>;
1111 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<ProjectionPredicate<'tcx>> {
1112 tcx.lift(&(self.projection_ty.trait_ref, self.ty)).map(|(trait_ref, ty)| {
1113 ProjectionPredicate {
1114 projection_ty: ProjectionTy {
1115 trait_ref: trait_ref,
1116 item_name: self.projection_ty.item_name
1124 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Binder<T> {
1125 type Lifted = Binder<T::Lifted>;
1126 fn lift_to_tcx(&self, tcx: &ctxt<'tcx>) -> Option<Self::Lifted> {
1127 tcx.lift(&self.0).map(|x| Binder(x))
1134 use session::Session;
1138 use syntax::codemap;
1140 /// Marker type used for the scoped TLS slot.
1141 /// The type context cannot be used directly because the scoped TLS
1142 /// in libstd doesn't allow types generic over lifetimes.
1143 struct ThreadLocalTyCx;
1145 scoped_thread_local!(static TLS_TCX: ThreadLocalTyCx);
1147 fn def_id_debug(def_id: ast::DefId, f: &mut fmt::Formatter) -> fmt::Result {
1148 // Unfortunately, there seems to be no way to attempt to print
1149 // a path for a def-id, so I'll just make a best effort for now
1150 // and otherwise fallback to just printing the crate/node pair
1152 if def_id.krate == ast::LOCAL_CRATE {
1153 match tcx.map.find(def_id.node) {
1154 Some(ast_map::NodeItem(..)) |
1155 Some(ast_map::NodeForeignItem(..)) |
1156 Some(ast_map::NodeImplItem(..)) |
1157 Some(ast_map::NodeTraitItem(..)) |
1158 Some(ast_map::NodeVariant(..)) |
1159 Some(ast_map::NodeStructCtor(..)) => {
1160 return write!(f, "{}", tcx.item_path_str(def_id));
1169 fn span_debug(span: codemap::Span, f: &mut fmt::Formatter) -> fmt::Result {
1171 write!(f, "{}", tcx.sess.codemap().span_to_string(span))
1175 pub fn enter<'tcx, F: FnOnce(&ty::ctxt<'tcx>) -> R, R>(tcx: ty::ctxt<'tcx>, f: F)
1177 let result = ast::DEF_ID_DEBUG.with(|def_id_dbg| {
1178 codemap::SPAN_DEBUG.with(|span_dbg| {
1179 let original_def_id_debug = def_id_dbg.get();
1180 def_id_dbg.set(def_id_debug);
1181 let original_span_debug = span_dbg.get();
1182 span_dbg.set(span_debug);
1183 let tls_ptr = &tcx as *const _ as *const ThreadLocalTyCx;
1184 let result = TLS_TCX.set(unsafe { &*tls_ptr }, || f(&tcx));
1185 def_id_dbg.set(original_def_id_debug);
1186 span_dbg.set(original_span_debug);
1193 pub fn with<F: FnOnce(&ty::ctxt) -> R, R>(f: F) -> R {
1194 TLS_TCX.with(|tcx| f(unsafe { &*(tcx as *const _ as *const ty::ctxt) }))
1198 // Flags that we track on types. These flags are propagated upwards
1199 // through the type during type construction, so that we can quickly
1200 // check whether the type has various kinds of types in it without
1201 // recursing over the type itself.
1203 flags TypeFlags: u32 {
1204 const HAS_PARAMS = 1 << 0,
1205 const HAS_SELF = 1 << 1,
1206 const HAS_TY_INFER = 1 << 2,
1207 const HAS_RE_INFER = 1 << 3,
1208 const HAS_RE_EARLY_BOUND = 1 << 4,
1209 const HAS_FREE_REGIONS = 1 << 5,
1210 const HAS_TY_ERR = 1 << 6,
1211 const HAS_PROJECTION = 1 << 7,
1212 const HAS_TY_CLOSURE = 1 << 8,
1214 // true if there are "names" of types and regions and so forth
1215 // that are local to a particular fn
1216 const HAS_LOCAL_NAMES = 1 << 9,
1218 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
1219 TypeFlags::HAS_SELF.bits |
1220 TypeFlags::HAS_RE_EARLY_BOUND.bits,
1222 // Flags representing the nominal content of a type,
1223 // computed by FlagsComputation. If you add a new nominal
1224 // flag, it should be added here too.
1225 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
1226 TypeFlags::HAS_SELF.bits |
1227 TypeFlags::HAS_TY_INFER.bits |
1228 TypeFlags::HAS_RE_INFER.bits |
1229 TypeFlags::HAS_RE_EARLY_BOUND.bits |
1230 TypeFlags::HAS_FREE_REGIONS.bits |
1231 TypeFlags::HAS_TY_ERR.bits |
1232 TypeFlags::HAS_PROJECTION.bits |
1233 TypeFlags::HAS_TY_CLOSURE.bits |
1234 TypeFlags::HAS_LOCAL_NAMES.bits,
1236 // Caches for type_is_sized, type_moves_by_default
1237 const SIZEDNESS_CACHED = 1 << 16,
1238 const IS_SIZED = 1 << 17,
1239 const MOVENESS_CACHED = 1 << 18,
1240 const MOVES_BY_DEFAULT = 1 << 19,
1244 macro_rules! sty_debug_print {
1245 ($ctxt: expr, $($variant: ident),*) => {{
1246 // curious inner module to allow variant names to be used as
1248 #[allow(non_snake_case)]
1251 #[derive(Copy, Clone)]
1254 region_infer: usize,
1259 pub fn go(tcx: &ty::ctxt) {
1260 let mut total = DebugStat {
1262 region_infer: 0, ty_infer: 0, both_infer: 0,
1264 $(let mut $variant = total;)*
1267 for (_, t) in tcx.interner.borrow().iter() {
1268 let variant = match t.sty {
1269 ty::TyBool | ty::TyChar | ty::TyInt(..) | ty::TyUint(..) |
1270 ty::TyFloat(..) | ty::TyStr => continue,
1271 ty::TyError => /* unimportant */ continue,
1272 $(ty::$variant(..) => &mut $variant,)*
1274 let region = t.flags.get().intersects(ty::TypeFlags::HAS_RE_INFER);
1275 let ty = t.flags.get().intersects(ty::TypeFlags::HAS_TY_INFER);
1279 if region { total.region_infer += 1; variant.region_infer += 1 }
1280 if ty { total.ty_infer += 1; variant.ty_infer += 1 }
1281 if region && ty { total.both_infer += 1; variant.both_infer += 1 }
1283 println!("Ty interner total ty region both");
1284 $(println!(" {:18}: {uses:6} {usespc:4.1}%, \
1285 {ty:4.1}% {region:5.1}% {both:4.1}%",
1286 stringify!($variant),
1287 uses = $variant.total,
1288 usespc = $variant.total as f64 * 100.0 / total.total as f64,
1289 ty = $variant.ty_infer as f64 * 100.0 / total.total as f64,
1290 region = $variant.region_infer as f64 * 100.0 / total.total as f64,
1291 both = $variant.both_infer as f64 * 100.0 / total.total as f64);
1293 println!(" total {uses:6} \
1294 {ty:4.1}% {region:5.1}% {both:4.1}%",
1296 ty = total.ty_infer as f64 * 100.0 / total.total as f64,
1297 region = total.region_infer as f64 * 100.0 / total.total as f64,
1298 both = total.both_infer as f64 * 100.0 / total.total as f64)
1306 impl<'tcx> ctxt<'tcx> {
1307 pub fn print_debug_stats(&self) {
1310 TyEnum, TyBox, TyArray, TySlice, TyRawPtr, TyRef, TyBareFn, TyTrait,
1311 TyStruct, TyClosure, TyTuple, TyParam, TyInfer, TyProjection);
1313 println!("Substs interner: #{}", self.substs_interner.borrow().len());
1314 println!("BareFnTy interner: #{}", self.bare_fn_interner.borrow().len());
1315 println!("Region interner: #{}", self.region_interner.borrow().len());
1316 println!("Stability interner: #{}", self.stability_interner.borrow().len());
1320 pub struct TyS<'tcx> {
1321 pub sty: TypeVariants<'tcx>,
1322 pub flags: Cell<TypeFlags>,
1324 // the maximal depth of any bound regions appearing in this type.
1328 impl fmt::Debug for TypeFlags {
1329 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1330 write!(f, "{}", self.bits)
1334 impl<'tcx> PartialEq for TyS<'tcx> {
1336 fn eq(&self, other: &TyS<'tcx>) -> bool {
1337 // (self as *const _) == (other as *const _)
1338 (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
1341 impl<'tcx> Eq for TyS<'tcx> {}
1343 impl<'tcx> Hash for TyS<'tcx> {
1344 fn hash<H: Hasher>(&self, s: &mut H) {
1345 (self as *const TyS).hash(s)
1349 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
1351 /// An entry in the type interner.
1352 pub struct InternedTy<'tcx> {
1356 // NB: An InternedTy compares and hashes as a sty.
1357 impl<'tcx> PartialEq for InternedTy<'tcx> {
1358 fn eq(&self, other: &InternedTy<'tcx>) -> bool {
1359 self.ty.sty == other.ty.sty
1363 impl<'tcx> Eq for InternedTy<'tcx> {}
1365 impl<'tcx> Hash for InternedTy<'tcx> {
1366 fn hash<H: Hasher>(&self, s: &mut H) {
1371 impl<'tcx> Borrow<TypeVariants<'tcx>> for InternedTy<'tcx> {
1372 fn borrow<'a>(&'a self) -> &'a TypeVariants<'tcx> {
1377 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
1378 pub struct BareFnTy<'tcx> {
1379 pub unsafety: ast::Unsafety,
1381 pub sig: PolyFnSig<'tcx>,
1384 #[derive(Clone, PartialEq, Eq, Hash)]
1385 pub struct ClosureTy<'tcx> {
1386 pub unsafety: ast::Unsafety,
1388 pub sig: PolyFnSig<'tcx>,
1391 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
1392 pub enum FnOutput<'tcx> {
1393 FnConverging(Ty<'tcx>),
1397 impl<'tcx> FnOutput<'tcx> {
1398 pub fn diverges(&self) -> bool {
1399 *self == FnDiverging
1402 pub fn unwrap(self) -> Ty<'tcx> {
1404 ty::FnConverging(t) => t,
1405 ty::FnDiverging => unreachable!()
1409 pub fn unwrap_or(self, def: Ty<'tcx>) -> Ty<'tcx> {
1411 ty::FnConverging(t) => t,
1412 ty::FnDiverging => def
1417 pub type PolyFnOutput<'tcx> = Binder<FnOutput<'tcx>>;
1419 impl<'tcx> PolyFnOutput<'tcx> {
1420 pub fn diverges(&self) -> bool {
1425 /// Signature of a function type, which I have arbitrarily
1426 /// decided to use to refer to the input/output types.
1428 /// - `inputs` is the list of arguments and their modes.
1429 /// - `output` is the return type.
1430 /// - `variadic` indicates whether this is a variadic function. (only true for foreign fns)
1431 #[derive(Clone, PartialEq, Eq, Hash)]
1432 pub struct FnSig<'tcx> {
1433 pub inputs: Vec<Ty<'tcx>>,
1434 pub output: FnOutput<'tcx>,
1438 pub type PolyFnSig<'tcx> = Binder<FnSig<'tcx>>;
1440 impl<'tcx> PolyFnSig<'tcx> {
1441 pub fn inputs(&self) -> ty::Binder<Vec<Ty<'tcx>>> {
1442 self.map_bound_ref(|fn_sig| fn_sig.inputs.clone())
1444 pub fn input(&self, index: usize) -> ty::Binder<Ty<'tcx>> {
1445 self.map_bound_ref(|fn_sig| fn_sig.inputs[index])
1447 pub fn output(&self) -> ty::Binder<FnOutput<'tcx>> {
1448 self.map_bound_ref(|fn_sig| fn_sig.output.clone())
1450 pub fn variadic(&self) -> bool {
1451 self.skip_binder().variadic
1455 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1456 pub struct ParamTy {
1457 pub space: subst::ParamSpace,
1459 pub name: ast::Name,
1462 /// A [De Bruijn index][dbi] is a standard means of representing
1463 /// regions (and perhaps later types) in a higher-ranked setting. In
1464 /// particular, imagine a type like this:
1466 /// for<'a> fn(for<'b> fn(&'b isize, &'a isize), &'a char)
1469 /// | +------------+ 1 | |
1471 /// +--------------------------------+ 2 |
1473 /// +------------------------------------------+ 1
1475 /// In this type, there are two binders (the outer fn and the inner
1476 /// fn). We need to be able to determine, for any given region, which
1477 /// fn type it is bound by, the inner or the outer one. There are
1478 /// various ways you can do this, but a De Bruijn index is one of the
1479 /// more convenient and has some nice properties. The basic idea is to
1480 /// count the number of binders, inside out. Some examples should help
1481 /// clarify what I mean.
1483 /// Let's start with the reference type `&'b isize` that is the first
1484 /// argument to the inner function. This region `'b` is assigned a De
1485 /// Bruijn index of 1, meaning "the innermost binder" (in this case, a
1486 /// fn). The region `'a` that appears in the second argument type (`&'a
1487 /// isize`) would then be assigned a De Bruijn index of 2, meaning "the
1488 /// second-innermost binder". (These indices are written on the arrays
1489 /// in the diagram).
1491 /// What is interesting is that De Bruijn index attached to a particular
1492 /// variable will vary depending on where it appears. For example,
1493 /// the final type `&'a char` also refers to the region `'a` declared on
1494 /// the outermost fn. But this time, this reference is not nested within
1495 /// any other binders (i.e., it is not an argument to the inner fn, but
1496 /// rather the outer one). Therefore, in this case, it is assigned a
1497 /// De Bruijn index of 1, because the innermost binder in that location
1498 /// is the outer fn.
1500 /// [dbi]: http://en.wikipedia.org/wiki/De_Bruijn_index
1501 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug, Copy)]
1502 pub struct DebruijnIndex {
1503 // We maintain the invariant that this is never 0. So 1 indicates
1504 // the innermost binder. To ensure this, create with `DebruijnIndex::new`.
1508 /// Representation of regions:
1509 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Copy)]
1511 // Region bound in a type or fn declaration which will be
1512 // substituted 'early' -- that is, at the same time when type
1513 // parameters are substituted.
1514 ReEarlyBound(EarlyBoundRegion),
1516 // Region bound in a function scope, which will be substituted when the
1517 // function is called.
1518 ReLateBound(DebruijnIndex, BoundRegion),
1520 /// When checking a function body, the types of all arguments and so forth
1521 /// that refer to bound region parameters are modified to refer to free
1522 /// region parameters.
1525 /// A concrete region naming some statically determined extent
1526 /// (e.g. an expression or sequence of statements) within the
1527 /// current function.
1528 ReScope(region::CodeExtent),
1530 /// Static data that has an "infinite" lifetime. Top in the region lattice.
1533 /// A region variable. Should not exist after typeck.
1534 ReInfer(InferRegion),
1536 /// Empty lifetime is for data that is never accessed.
1537 /// Bottom in the region lattice. We treat ReEmpty somewhat
1538 /// specially; at least right now, we do not generate instances of
1539 /// it during the GLB computations, but rather
1540 /// generate an error instead. This is to improve error messages.
1541 /// The only way to get an instance of ReEmpty is to have a region
1542 /// variable with no constraints.
1546 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug)]
1547 pub struct EarlyBoundRegion {
1548 pub param_id: ast::NodeId,
1549 pub space: subst::ParamSpace,
1551 pub name: ast::Name,
1554 /// Upvars do not get their own node-id. Instead, we use the pair of
1555 /// the original var id (that is, the root variable that is referenced
1556 /// by the upvar) and the id of the closure expression.
1557 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
1558 pub struct UpvarId {
1559 pub var_id: ast::NodeId,
1560 pub closure_expr_id: ast::NodeId,
1563 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
1564 pub enum BorrowKind {
1565 /// Data must be immutable and is aliasable.
1568 /// Data must be immutable but not aliasable. This kind of borrow
1569 /// cannot currently be expressed by the user and is used only in
1570 /// implicit closure bindings. It is needed when you the closure
1571 /// is borrowing or mutating a mutable referent, e.g.:
1573 /// let x: &mut isize = ...;
1574 /// let y = || *x += 5;
1576 /// If we were to try to translate this closure into a more explicit
1577 /// form, we'd encounter an error with the code as written:
1579 /// struct Env { x: & &mut isize }
1580 /// let x: &mut isize = ...;
1581 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
1582 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
1584 /// This is then illegal because you cannot mutate a `&mut` found
1585 /// in an aliasable location. To solve, you'd have to translate with
1586 /// an `&mut` borrow:
1588 /// struct Env { x: & &mut isize }
1589 /// let x: &mut isize = ...;
1590 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
1591 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
1593 /// Now the assignment to `**env.x` is legal, but creating a
1594 /// mutable pointer to `x` is not because `x` is not mutable. We
1595 /// could fix this by declaring `x` as `let mut x`. This is ok in
1596 /// user code, if awkward, but extra weird for closures, since the
1597 /// borrow is hidden.
1599 /// So we introduce a "unique imm" borrow -- the referent is
1600 /// immutable, but not aliasable. This solves the problem. For
1601 /// simplicity, we don't give users the way to express this
1602 /// borrow, it's just used when translating closures.
1605 /// Data is mutable and not aliasable.
1609 /// Information describing the capture of an upvar. This is computed
1610 /// during `typeck`, specifically by `regionck`.
1611 #[derive(PartialEq, Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
1612 pub enum UpvarCapture {
1613 /// Upvar is captured by value. This is always true when the
1614 /// closure is labeled `move`, but can also be true in other cases
1615 /// depending on inference.
1618 /// Upvar is captured by reference.
1622 #[derive(PartialEq, Clone, RustcEncodable, RustcDecodable, Copy)]
1623 pub struct UpvarBorrow {
1624 /// The kind of borrow: by-ref upvars have access to shared
1625 /// immutable borrows, which are not part of the normal language
1627 pub kind: BorrowKind,
1629 /// Region of the resulting reference.
1630 pub region: ty::Region,
1633 pub type UpvarCaptureMap = FnvHashMap<UpvarId, UpvarCapture>;
1635 #[derive(Copy, Clone)]
1636 pub struct ClosureUpvar<'tcx> {
1643 pub fn is_bound(&self) -> bool {
1645 ty::ReEarlyBound(..) => true,
1646 ty::ReLateBound(..) => true,
1651 pub fn escapes_depth(&self, depth: u32) -> bool {
1653 ty::ReLateBound(debruijn, _) => debruijn.depth > depth,
1658 /// Returns the depth of `self` from the (1-based) binding level `depth`
1659 pub fn from_depth(&self, depth: u32) -> Region {
1661 ty::ReLateBound(debruijn, r) => ty::ReLateBound(DebruijnIndex {
1662 depth: debruijn.depth - (depth - 1)
1669 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash,
1670 RustcEncodable, RustcDecodable, Copy)]
1671 /// A "free" region `fr` can be interpreted as "some region
1672 /// at least as big as the scope `fr.scope`".
1673 pub struct FreeRegion {
1674 pub scope: region::DestructionScopeData,
1675 pub bound_region: BoundRegion
1678 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash,
1679 RustcEncodable, RustcDecodable, Copy, Debug)]
1680 pub enum BoundRegion {
1681 /// An anonymous region parameter for a given fn (&T)
1684 /// Named region parameters for functions (a in &'a T)
1686 /// The def-id is needed to distinguish free regions in
1687 /// the event of shadowing.
1688 BrNamed(ast::DefId, ast::Name),
1690 /// Fresh bound identifiers created during GLB computations.
1693 // Anonymous region for the implicit env pointer parameter
1698 // NB: If you change this, you'll probably want to change the corresponding
1699 // AST structure in libsyntax/ast.rs as well.
1700 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
1701 pub enum TypeVariants<'tcx> {
1702 /// The primitive boolean type. Written as `bool`.
1705 /// The primitive character type; holds a Unicode scalar value
1706 /// (a non-surrogate code point). Written as `char`.
1709 /// A primitive signed integer type. For example, `i32`.
1712 /// A primitive unsigned integer type. For example, `u32`.
1713 TyUint(ast::UintTy),
1715 /// A primitive floating-point type. For example, `f64`.
1716 TyFloat(ast::FloatTy),
1718 /// An enumerated type, defined with `enum`.
1720 /// Substs here, possibly against intuition, *may* contain `TyParam`s.
1721 /// That is, even after substitution it is possible that there are type
1722 /// variables. This happens when the `TyEnum` corresponds to an enum
1723 /// definition and not a concrete use of it. To get the correct `TyEnum`
1724 /// from the tcx, use the `NodeId` from the `ast::Ty` and look it up in
1725 /// the `ast_ty_to_ty_cache`. This is probably true for `TyStruct` as
1727 TyEnum(DefId, &'tcx Substs<'tcx>),
1729 /// A structure type, defined with `struct`.
1731 /// See warning about substitutions for enumerated types.
1732 TyStruct(DefId, &'tcx Substs<'tcx>),
1734 /// `Box<T>`; this is nominally a struct in the documentation, but is
1735 /// special-cased internally. For example, it is possible to implicitly
1736 /// move the contents of a box out of that box, and methods of any type
1737 /// can have type `Box<Self>`.
1740 /// The pointee of a string slice. Written as `str`.
1743 /// An array with the given length. Written as `[T; n]`.
1744 TyArray(Ty<'tcx>, usize),
1746 /// The pointee of an array slice. Written as `[T]`.
1749 /// A raw pointer. Written as `*mut T` or `*const T`
1750 TyRawPtr(TypeAndMut<'tcx>),
1752 /// A reference; a pointer with an associated lifetime. Written as
1753 /// `&a mut T` or `&'a T`.
1754 TyRef(&'tcx Region, TypeAndMut<'tcx>),
1756 /// If the def-id is Some(_), then this is the type of a specific
1757 /// fn item. Otherwise, if None(_), it a fn pointer type.
1759 /// FIXME: Conflating function pointers and the type of a
1760 /// function is probably a terrible idea; a function pointer is a
1761 /// value with a specific type, but a function can be polymorphic
1762 /// or dynamically dispatched.
1763 TyBareFn(Option<DefId>, &'tcx BareFnTy<'tcx>),
1765 /// A trait, defined with `trait`.
1766 TyTrait(Box<TraitTy<'tcx>>),
1768 /// The anonymous type of a closure. Used to represent the type of
1770 TyClosure(DefId, Box<ClosureSubsts<'tcx>>),
1772 /// A tuple type. For example, `(i32, bool)`.
1773 TyTuple(Vec<Ty<'tcx>>),
1775 /// The projection of an associated type. For example,
1776 /// `<T as Trait<..>>::N`.
1777 TyProjection(ProjectionTy<'tcx>),
1779 /// A type parameter; for example, `T` in `fn f<T>(x: T) {}
1782 /// A type variable used during type-checking.
1785 /// A placeholder for a type which could not be computed; this is
1786 /// propagated to avoid useless error messages.
1790 /// A closure can be modeled as a struct that looks like:
1792 /// struct Closure<'l0...'li, T0...Tj, U0...Uk> {
1798 /// where 'l0...'li and T0...Tj are the lifetime and type parameters
1799 /// in scope on the function that defined the closure, and U0...Uk are
1800 /// type parameters representing the types of its upvars (borrowed, if
1803 /// So, for example, given this function:
1805 /// fn foo<'a, T>(data: &'a mut T) {
1806 /// do(|| data.count += 1)
1809 /// the type of the closure would be something like:
1811 /// struct Closure<'a, T, U0> {
1815 /// Note that the type of the upvar is not specified in the struct.
1816 /// You may wonder how the impl would then be able to use the upvar,
1817 /// if it doesn't know it's type? The answer is that the impl is
1818 /// (conceptually) not fully generic over Closure but rather tied to
1819 /// instances with the expected upvar types:
1821 /// impl<'b, 'a, T> FnMut() for Closure<'a, T, &'b mut &'a mut T> {
1825 /// You can see that the *impl* fully specified the type of the upvar
1826 /// and thus knows full well that `data` has type `&'b mut &'a mut T`.
1827 /// (Here, I am assuming that `data` is mut-borrowed.)
1829 /// Now, the last question you may ask is: Why include the upvar types
1830 /// as extra type parameters? The reason for this design is that the
1831 /// upvar types can reference lifetimes that are internal to the
1832 /// creating function. In my example above, for example, the lifetime
1833 /// `'b` represents the extent of the closure itself; this is some
1834 /// subset of `foo`, probably just the extent of the call to the to
1835 /// `do()`. If we just had the lifetime/type parameters from the
1836 /// enclosing function, we couldn't name this lifetime `'b`. Note that
1837 /// there can also be lifetimes in the types of the upvars themselves,
1838 /// if one of them happens to be a reference to something that the
1839 /// creating fn owns.
1841 /// OK, you say, so why not create a more minimal set of parameters
1842 /// that just includes the extra lifetime parameters? The answer is
1843 /// primarily that it would be hard --- we don't know at the time when
1844 /// we create the closure type what the full types of the upvars are,
1845 /// nor do we know which are borrowed and which are not. In this
1846 /// design, we can just supply a fresh type parameter and figure that
1849 /// All right, you say, but why include the type parameters from the
1850 /// original function then? The answer is that trans may need them
1851 /// when monomorphizing, and they may not appear in the upvars. A
1852 /// closure could capture no variables but still make use of some
1853 /// in-scope type parameter with a bound (e.g., if our example above
1854 /// had an extra `U: Default`, and the closure called `U::default()`).
1856 /// There is another reason. This design (implicitly) prohibits
1857 /// closures from capturing themselves (except via a trait
1858 /// object). This simplifies closure inference considerably, since it
1859 /// means that when we infer the kind of a closure or its upvars, we
1860 /// don't have to handle cycles where the decisions we make for
1861 /// closure C wind up influencing the decisions we ought to make for
1862 /// closure C (which would then require fixed point iteration to
1863 /// handle). Plus it fixes an ICE. :P
1864 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
1865 pub struct ClosureSubsts<'tcx> {
1866 /// Lifetime and type parameters from the enclosing function.
1867 /// These are separated out because trans wants to pass them around
1868 /// when monomorphizing.
1869 pub func_substs: &'tcx Substs<'tcx>,
1871 /// The types of the upvars. The list parallels the freevars and
1872 /// `upvar_borrows` lists. These are kept distinct so that we can
1873 /// easily index into them.
1874 pub upvar_tys: Vec<Ty<'tcx>>
1877 #[derive(Clone, PartialEq, Eq, Hash)]
1878 pub struct TraitTy<'tcx> {
1879 pub principal: ty::PolyTraitRef<'tcx>,
1880 pub bounds: ExistentialBounds<'tcx>,
1883 impl<'tcx> TraitTy<'tcx> {
1884 pub fn principal_def_id(&self) -> ast::DefId {
1885 self.principal.0.def_id
1888 /// Object types don't have a self-type specified. Therefore, when
1889 /// we convert the principal trait-ref into a normal trait-ref,
1890 /// you must give *some* self-type. A common choice is `mk_err()`
1891 /// or some skolemized type.
1892 pub fn principal_trait_ref_with_self_ty(&self,
1895 -> ty::PolyTraitRef<'tcx>
1897 // otherwise the escaping regions would be captured by the binder
1898 assert!(!self_ty.has_escaping_regions());
1900 ty::Binder(TraitRef {
1901 def_id: self.principal.0.def_id,
1902 substs: tcx.mk_substs(self.principal.0.substs.with_self_ty(self_ty)),
1906 pub fn projection_bounds_with_self_ty(&self,
1909 -> Vec<ty::PolyProjectionPredicate<'tcx>>
1911 // otherwise the escaping regions would be captured by the binders
1912 assert!(!self_ty.has_escaping_regions());
1914 self.bounds.projection_bounds.iter()
1915 .map(|in_poly_projection_predicate| {
1916 let in_projection_ty = &in_poly_projection_predicate.0.projection_ty;
1917 let substs = tcx.mk_substs(in_projection_ty.trait_ref.substs.with_self_ty(self_ty));
1918 let trait_ref = ty::TraitRef::new(in_projection_ty.trait_ref.def_id,
1920 let projection_ty = ty::ProjectionTy {
1921 trait_ref: trait_ref,
1922 item_name: in_projection_ty.item_name
1924 ty::Binder(ty::ProjectionPredicate {
1925 projection_ty: projection_ty,
1926 ty: in_poly_projection_predicate.0.ty
1933 /// A complete reference to a trait. These take numerous guises in syntax,
1934 /// but perhaps the most recognizable form is in a where clause:
1938 /// This would be represented by a trait-reference where the def-id is the
1939 /// def-id for the trait `Foo` and the substs defines `T` as parameter 0 in the
1940 /// `SelfSpace` and `U` as parameter 0 in the `TypeSpace`.
1942 /// Trait references also appear in object types like `Foo<U>`, but in
1943 /// that case the `Self` parameter is absent from the substitutions.
1945 /// Note that a `TraitRef` introduces a level of region binding, to
1946 /// account for higher-ranked trait bounds like `T : for<'a> Foo<&'a
1947 /// U>` or higher-ranked object types.
1948 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
1949 pub struct TraitRef<'tcx> {
1951 pub substs: &'tcx Substs<'tcx>,
1954 pub type PolyTraitRef<'tcx> = Binder<TraitRef<'tcx>>;
1956 impl<'tcx> PolyTraitRef<'tcx> {
1957 pub fn self_ty(&self) -> Ty<'tcx> {
1961 pub fn def_id(&self) -> ast::DefId {
1965 pub fn substs(&self) -> &'tcx Substs<'tcx> {
1966 // FIXME(#20664) every use of this fn is probably a bug, it should yield Binder<>
1970 pub fn input_types(&self) -> &[Ty<'tcx>] {
1971 // FIXME(#20664) every use of this fn is probably a bug, it should yield Binder<>
1972 self.0.input_types()
1975 pub fn to_poly_trait_predicate(&self) -> PolyTraitPredicate<'tcx> {
1976 // Note that we preserve binding levels
1977 Binder(TraitPredicate { trait_ref: self.0.clone() })
1981 /// Binder is a binder for higher-ranked lifetimes. It is part of the
1982 /// compiler's representation for things like `for<'a> Fn(&'a isize)`
1983 /// (which would be represented by the type `PolyTraitRef ==
1984 /// Binder<TraitRef>`). Note that when we skolemize, instantiate,
1985 /// erase, or otherwise "discharge" these bound regions, we change the
1986 /// type from `Binder<T>` to just `T` (see
1987 /// e.g. `liberate_late_bound_regions`).
1988 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
1989 pub struct Binder<T>(pub T);
1992 /// Skips the binder and returns the "bound" value. This is a
1993 /// risky thing to do because it's easy to get confused about
1994 /// debruijn indices and the like. It is usually better to
1995 /// discharge the binder using `no_late_bound_regions` or
1996 /// `replace_late_bound_regions` or something like
1997 /// that. `skip_binder` is only valid when you are either
1998 /// extracting data that has nothing to do with bound regions, you
1999 /// are doing some sort of test that does not involve bound
2000 /// regions, or you are being very careful about your depth
2003 /// Some examples where `skip_binder` is reasonable:
2004 /// - extracting the def-id from a PolyTraitRef;
2005 /// - comparing the self type of a PolyTraitRef to see if it is equal to
2006 /// a type parameter `X`, since the type `X` does not reference any regions
2007 pub fn skip_binder(&self) -> &T {
2011 pub fn as_ref(&self) -> Binder<&T> {
2015 pub fn map_bound_ref<F,U>(&self, f: F) -> Binder<U>
2016 where F: FnOnce(&T) -> U
2018 self.as_ref().map_bound(f)
2021 pub fn map_bound<F,U>(self, f: F) -> Binder<U>
2022 where F: FnOnce(T) -> U
2024 ty::Binder(f(self.0))
2028 #[derive(Clone, Copy, PartialEq)]
2029 pub enum IntVarValue {
2030 IntType(ast::IntTy),
2031 UintType(ast::UintTy),
2034 #[derive(Clone, Copy, Debug)]
2035 pub struct ExpectedFound<T> {
2040 // Data structures used in type unification
2041 #[derive(Clone, Copy, Debug)]
2042 pub enum TypeError<'tcx> {
2044 UnsafetyMismatch(ExpectedFound<ast::Unsafety>),
2045 AbiMismatch(ExpectedFound<abi::Abi>),
2051 TupleSize(ExpectedFound<usize>),
2052 FixedArraySize(ExpectedFound<usize>),
2053 TyParamSize(ExpectedFound<usize>),
2055 RegionsDoesNotOutlive(Region, Region),
2056 RegionsNotSame(Region, Region),
2057 RegionsNoOverlap(Region, Region),
2058 RegionsInsufficientlyPolymorphic(BoundRegion, Region),
2059 RegionsOverlyPolymorphic(BoundRegion, Region),
2060 Sorts(ExpectedFound<Ty<'tcx>>),
2062 IntMismatch(ExpectedFound<IntVarValue>),
2063 FloatMismatch(ExpectedFound<ast::FloatTy>),
2064 Traits(ExpectedFound<ast::DefId>),
2065 BuiltinBoundsMismatch(ExpectedFound<BuiltinBounds>),
2066 VariadicMismatch(ExpectedFound<bool>),
2068 ConvergenceMismatch(ExpectedFound<bool>),
2069 ProjectionNameMismatched(ExpectedFound<ast::Name>),
2070 ProjectionBoundsLength(ExpectedFound<usize>),
2071 terr_ty_param_default_mismatch(expected_found<Ty<'tcx>>)
2074 /// Bounds suitable for an existentially quantified type parameter
2075 /// such as those that appear in object types or closure types.
2076 #[derive(PartialEq, Eq, Hash, Clone)]
2077 pub struct ExistentialBounds<'tcx> {
2078 pub region_bound: ty::Region,
2079 pub builtin_bounds: BuiltinBounds,
2080 pub projection_bounds: Vec<PolyProjectionPredicate<'tcx>>,
2083 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
2084 pub struct BuiltinBounds(EnumSet<BuiltinBound>);
2086 impl BuiltinBounds {
2087 pub fn empty() -> BuiltinBounds {
2088 BuiltinBounds(EnumSet::new())
2091 pub fn iter(&self) -> enum_set::Iter<BuiltinBound> {
2095 pub fn to_predicates<'tcx>(&self,
2096 tcx: &ty::ctxt<'tcx>,
2097 self_ty: Ty<'tcx>) -> Vec<Predicate<'tcx>> {
2098 self.iter().filter_map(|builtin_bound|
2099 match traits::trait_ref_for_builtin_bound(tcx, builtin_bound, self_ty) {
2100 Ok(trait_ref) => Some(trait_ref.to_predicate()),
2101 Err(ErrorReported) => { None }
2107 impl ops::Deref for BuiltinBounds {
2108 type Target = EnumSet<BuiltinBound>;
2109 fn deref(&self) -> &Self::Target { &self.0 }
2112 impl ops::DerefMut for BuiltinBounds {
2113 fn deref_mut(&mut self) -> &mut Self::Target { &mut self.0 }
2116 impl<'a> IntoIterator for &'a BuiltinBounds {
2117 type Item = BuiltinBound;
2118 type IntoIter = enum_set::Iter<BuiltinBound>;
2119 fn into_iter(self) -> Self::IntoIter {
2120 (**self).into_iter()
2124 #[derive(Clone, RustcEncodable, PartialEq, Eq, RustcDecodable, Hash,
2127 pub enum BuiltinBound {
2134 impl CLike for BuiltinBound {
2135 fn to_usize(&self) -> usize {
2138 fn from_usize(v: usize) -> BuiltinBound {
2139 unsafe { mem::transmute(v) }
2143 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2148 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2153 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2154 pub struct FloatVid {
2158 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
2159 pub struct RegionVid {
2163 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
2169 /// A `FreshTy` is one that is generated as a replacement for an
2170 /// unbound type variable. This is convenient for caching etc. See
2171 /// `middle::infer::freshen` for more details.
2177 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
2178 pub enum UnconstrainedNumeric {
2185 #[derive(Clone, RustcEncodable, RustcDecodable, Eq, Hash, Debug, Copy)]
2186 pub enum InferRegion {
2188 ReSkolemized(u32, BoundRegion)
2191 impl cmp::PartialEq for InferRegion {
2192 fn eq(&self, other: &InferRegion) -> bool {
2193 match ((*self), *other) {
2194 (ReVar(rva), ReVar(rvb)) => {
2197 (ReSkolemized(rva, _), ReSkolemized(rvb, _)) => {
2203 fn ne(&self, other: &InferRegion) -> bool {
2204 !((*self) == (*other))
2208 impl fmt::Debug for TyVid {
2209 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2210 write!(f, "_#{}t", self.index)
2214 impl fmt::Debug for IntVid {
2215 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2216 write!(f, "_#{}i", self.index)
2220 impl fmt::Debug for FloatVid {
2221 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2222 write!(f, "_#{}f", self.index)
2226 impl fmt::Debug for RegionVid {
2227 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2228 write!(f, "'_#{}r", self.index)
2232 impl<'tcx> fmt::Debug for FnSig<'tcx> {
2233 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2234 write!(f, "({:?}; variadic: {})->{:?}", self.inputs, self.variadic, self.output)
2238 impl fmt::Debug for InferTy {
2239 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2241 TyVar(ref v) => v.fmt(f),
2242 IntVar(ref v) => v.fmt(f),
2243 FloatVar(ref v) => v.fmt(f),
2244 FreshTy(v) => write!(f, "FreshTy({:?})", v),
2245 FreshIntTy(v) => write!(f, "FreshIntTy({:?})", v),
2246 FreshFloatTy(v) => write!(f, "FreshFloatTy({:?})", v)
2251 impl fmt::Debug for IntVarValue {
2252 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2254 IntType(ref v) => v.fmt(f),
2255 UintType(ref v) => v.fmt(f),
2260 /// Default region to use for the bound of objects that are
2261 /// supplied as the value for this type parameter. This is derived
2262 /// from `T:'a` annotations appearing in the type definition. If
2263 /// this is `None`, then the default is inherited from the
2264 /// surrounding context. See RFC #599 for details.
2265 #[derive(Copy, Clone)]
2266 pub enum ObjectLifetimeDefault {
2267 /// Require an explicit annotation. Occurs when multiple
2268 /// `T:'a` constraints are found.
2271 /// Use the base default, typically 'static, but in a fn body it is a fresh variable
2274 /// Use the given region as the default.
2279 pub struct TypeParameterDef<'tcx> {
2280 pub name: ast::Name,
2281 pub def_id: ast::DefId,
2282 pub space: subst::ParamSpace,
2284 pub default: Option<Ty<'tcx>>,
2285 pub object_lifetime_default: ObjectLifetimeDefault,
2288 #[derive(RustcEncodable, RustcDecodable, Clone, Debug)]
2289 pub struct RegionParameterDef {
2290 pub name: ast::Name,
2291 pub def_id: ast::DefId,
2292 pub space: subst::ParamSpace,
2294 pub bounds: Vec<ty::Region>,
2297 impl RegionParameterDef {
2298 pub fn to_early_bound_region(&self) -> ty::Region {
2299 ty::ReEarlyBound(ty::EarlyBoundRegion {
2300 param_id: self.def_id.node,
2306 pub fn to_bound_region(&self) -> ty::BoundRegion {
2307 ty::BoundRegion::BrNamed(self.def_id, self.name)
2311 /// Information about the formal type/lifetime parameters associated
2312 /// with an item or method. Analogous to ast::Generics.
2313 #[derive(Clone, Debug)]
2314 pub struct Generics<'tcx> {
2315 pub types: VecPerParamSpace<TypeParameterDef<'tcx>>,
2316 pub regions: VecPerParamSpace<RegionParameterDef>,
2319 impl<'tcx> Generics<'tcx> {
2320 pub fn empty() -> Generics<'tcx> {
2322 types: VecPerParamSpace::empty(),
2323 regions: VecPerParamSpace::empty(),
2327 pub fn is_empty(&self) -> bool {
2328 self.types.is_empty() && self.regions.is_empty()
2331 pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
2332 !self.types.is_empty_in(space)
2335 pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
2336 !self.regions.is_empty_in(space)
2340 /// Bounds on generics.
2342 pub struct GenericPredicates<'tcx> {
2343 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
2346 impl<'tcx> GenericPredicates<'tcx> {
2347 pub fn empty() -> GenericPredicates<'tcx> {
2349 predicates: VecPerParamSpace::empty(),
2353 pub fn instantiate(&self, tcx: &ctxt<'tcx>, substs: &Substs<'tcx>)
2354 -> InstantiatedPredicates<'tcx> {
2355 InstantiatedPredicates {
2356 predicates: self.predicates.subst(tcx, substs),
2360 pub fn instantiate_supertrait(&self,
2362 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
2363 -> InstantiatedPredicates<'tcx>
2365 InstantiatedPredicates {
2366 predicates: self.predicates.map(|pred| pred.subst_supertrait(tcx, poly_trait_ref))
2371 #[derive(Clone, PartialEq, Eq, Hash)]
2372 pub enum Predicate<'tcx> {
2373 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
2374 /// the `Self` type of the trait reference and `A`, `B`, and `C`
2375 /// would be the parameters in the `TypeSpace`.
2376 Trait(PolyTraitPredicate<'tcx>),
2378 /// where `T1 == T2`.
2379 Equate(PolyEquatePredicate<'tcx>),
2382 RegionOutlives(PolyRegionOutlivesPredicate),
2385 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
2387 /// where <T as TraitRef>::Name == X, approximately.
2388 /// See `ProjectionPredicate` struct for details.
2389 Projection(PolyProjectionPredicate<'tcx>),
2392 impl<'tcx> Predicate<'tcx> {
2393 /// Performs a substitution suitable for going from a
2394 /// poly-trait-ref to supertraits that must hold if that
2395 /// poly-trait-ref holds. This is slightly different from a normal
2396 /// substitution in terms of what happens with bound regions. See
2397 /// lengthy comment below for details.
2398 pub fn subst_supertrait(&self,
2400 trait_ref: &ty::PolyTraitRef<'tcx>)
2401 -> ty::Predicate<'tcx>
2403 // The interaction between HRTB and supertraits is not entirely
2404 // obvious. Let me walk you (and myself) through an example.
2406 // Let's start with an easy case. Consider two traits:
2408 // trait Foo<'a> : Bar<'a,'a> { }
2409 // trait Bar<'b,'c> { }
2411 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
2412 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
2413 // knew that `Foo<'x>` (for any 'x) then we also know that
2414 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
2415 // normal substitution.
2417 // In terms of why this is sound, the idea is that whenever there
2418 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
2419 // holds. So if there is an impl of `T:Foo<'a>` that applies to
2420 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
2423 // Another example to be careful of is this:
2425 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
2426 // trait Bar1<'b,'c> { }
2428 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
2429 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
2430 // reason is similar to the previous example: any impl of
2431 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
2432 // basically we would want to collapse the bound lifetimes from
2433 // the input (`trait_ref`) and the supertraits.
2435 // To achieve this in practice is fairly straightforward. Let's
2436 // consider the more complicated scenario:
2438 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
2439 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
2440 // where both `'x` and `'b` would have a DB index of 1.
2441 // The substitution from the input trait-ref is therefore going to be
2442 // `'a => 'x` (where `'x` has a DB index of 1).
2443 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
2444 // early-bound parameter and `'b' is a late-bound parameter with a
2446 // - If we replace `'a` with `'x` from the input, it too will have
2447 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
2448 // just as we wanted.
2450 // There is only one catch. If we just apply the substitution `'a
2451 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
2452 // adjust the DB index because we substituting into a binder (it
2453 // tries to be so smart...) resulting in `for<'x> for<'b>
2454 // Bar1<'x,'b>` (we have no syntax for this, so use your
2455 // imagination). Basically the 'x will have DB index of 2 and 'b
2456 // will have DB index of 1. Not quite what we want. So we apply
2457 // the substitution to the *contents* of the trait reference,
2458 // rather than the trait reference itself (put another way, the
2459 // substitution code expects equal binding levels in the values
2460 // from the substitution and the value being substituted into, and
2461 // this trick achieves that).
2463 let substs = &trait_ref.0.substs;
2465 Predicate::Trait(ty::Binder(ref data)) =>
2466 Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
2467 Predicate::Equate(ty::Binder(ref data)) =>
2468 Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
2469 Predicate::RegionOutlives(ty::Binder(ref data)) =>
2470 Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
2471 Predicate::TypeOutlives(ty::Binder(ref data)) =>
2472 Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
2473 Predicate::Projection(ty::Binder(ref data)) =>
2474 Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
2479 #[derive(Clone, PartialEq, Eq, Hash)]
2480 pub struct TraitPredicate<'tcx> {
2481 pub trait_ref: TraitRef<'tcx>
2483 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
2485 impl<'tcx> TraitPredicate<'tcx> {
2486 pub fn def_id(&self) -> ast::DefId {
2487 self.trait_ref.def_id
2490 pub fn input_types(&self) -> &[Ty<'tcx>] {
2491 self.trait_ref.substs.types.as_slice()
2494 pub fn self_ty(&self) -> Ty<'tcx> {
2495 self.trait_ref.self_ty()
2499 impl<'tcx> PolyTraitPredicate<'tcx> {
2500 pub fn def_id(&self) -> ast::DefId {
2505 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
2506 pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
2507 pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
2509 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
2510 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
2511 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
2512 pub type PolyRegionOutlivesPredicate = PolyOutlivesPredicate<ty::Region, ty::Region>;
2513 pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region>;
2515 /// This kind of predicate has no *direct* correspondent in the
2516 /// syntax, but it roughly corresponds to the syntactic forms:
2518 /// 1. `T : TraitRef<..., Item=Type>`
2519 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
2521 /// In particular, form #1 is "desugared" to the combination of a
2522 /// normal trait predicate (`T : TraitRef<...>`) and one of these
2523 /// predicates. Form #2 is a broader form in that it also permits
2524 /// equality between arbitrary types. Processing an instance of Form
2525 /// #2 eventually yields one of these `ProjectionPredicate`
2526 /// instances to normalize the LHS.
2527 #[derive(Clone, PartialEq, Eq, Hash)]
2528 pub struct ProjectionPredicate<'tcx> {
2529 pub projection_ty: ProjectionTy<'tcx>,
2533 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
2535 impl<'tcx> PolyProjectionPredicate<'tcx> {
2536 pub fn item_name(&self) -> ast::Name {
2537 self.0.projection_ty.item_name // safe to skip the binder to access a name
2540 pub fn sort_key(&self) -> (ast::DefId, ast::Name) {
2541 self.0.projection_ty.sort_key()
2545 /// Represents the projection of an associated type. In explicit UFCS
2546 /// form this would be written `<T as Trait<..>>::N`.
2547 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
2548 pub struct ProjectionTy<'tcx> {
2549 /// The trait reference `T as Trait<..>`.
2550 pub trait_ref: ty::TraitRef<'tcx>,
2552 /// The name `N` of the associated type.
2553 pub item_name: ast::Name,
2556 impl<'tcx> ProjectionTy<'tcx> {
2557 pub fn sort_key(&self) -> (ast::DefId, ast::Name) {
2558 (self.trait_ref.def_id, self.item_name)
2562 pub trait ToPolyTraitRef<'tcx> {
2563 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
2566 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
2567 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
2568 assert!(!self.has_escaping_regions());
2569 ty::Binder(self.clone())
2573 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
2574 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
2575 self.map_bound_ref(|trait_pred| trait_pred.trait_ref.clone())
2579 impl<'tcx> ToPolyTraitRef<'tcx> for PolyProjectionPredicate<'tcx> {
2580 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
2581 // Note: unlike with TraitRef::to_poly_trait_ref(),
2582 // self.0.trait_ref is permitted to have escaping regions.
2583 // This is because here `self` has a `Binder` and so does our
2584 // return value, so we are preserving the number of binding
2586 ty::Binder(self.0.projection_ty.trait_ref.clone())
2590 pub trait ToPredicate<'tcx> {
2591 fn to_predicate(&self) -> Predicate<'tcx>;
2594 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
2595 fn to_predicate(&self) -> Predicate<'tcx> {
2596 // we're about to add a binder, so let's check that we don't
2597 // accidentally capture anything, or else that might be some
2598 // weird debruijn accounting.
2599 assert!(!self.has_escaping_regions());
2601 ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
2602 trait_ref: self.clone()
2607 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
2608 fn to_predicate(&self) -> Predicate<'tcx> {
2609 ty::Predicate::Trait(self.to_poly_trait_predicate())
2613 impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
2614 fn to_predicate(&self) -> Predicate<'tcx> {
2615 Predicate::Equate(self.clone())
2619 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate {
2620 fn to_predicate(&self) -> Predicate<'tcx> {
2621 Predicate::RegionOutlives(self.clone())
2625 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
2626 fn to_predicate(&self) -> Predicate<'tcx> {
2627 Predicate::TypeOutlives(self.clone())
2631 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
2632 fn to_predicate(&self) -> Predicate<'tcx> {
2633 Predicate::Projection(self.clone())
2637 impl<'tcx> Predicate<'tcx> {
2638 /// Iterates over the types in this predicate. Note that in all
2639 /// cases this is skipping over a binder, so late-bound regions
2640 /// with depth 0 are bound by the predicate.
2641 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
2642 let vec: Vec<_> = match *self {
2643 ty::Predicate::Trait(ref data) => {
2644 data.0.trait_ref.substs.types.as_slice().to_vec()
2646 ty::Predicate::Equate(ty::Binder(ref data)) => {
2647 vec![data.0, data.1]
2649 ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
2652 ty::Predicate::RegionOutlives(..) => {
2655 ty::Predicate::Projection(ref data) => {
2656 let trait_inputs = data.0.projection_ty.trait_ref.substs.types.as_slice();
2659 .chain(Some(data.0.ty))
2664 // The only reason to collect into a vector here is that I was
2665 // too lazy to make the full (somewhat complicated) iterator
2666 // type that would be needed here. But I wanted this fn to
2667 // return an iterator conceptually, rather than a `Vec`, so as
2668 // to be closer to `Ty::walk`.
2672 pub fn has_escaping_regions(&self) -> bool {
2674 Predicate::Trait(ref trait_ref) => trait_ref.has_escaping_regions(),
2675 Predicate::Equate(ref p) => p.has_escaping_regions(),
2676 Predicate::RegionOutlives(ref p) => p.has_escaping_regions(),
2677 Predicate::TypeOutlives(ref p) => p.has_escaping_regions(),
2678 Predicate::Projection(ref p) => p.has_escaping_regions(),
2682 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
2684 Predicate::Trait(ref t) => {
2685 Some(t.to_poly_trait_ref())
2687 Predicate::Projection(..) |
2688 Predicate::Equate(..) |
2689 Predicate::RegionOutlives(..) |
2690 Predicate::TypeOutlives(..) => {
2697 /// Represents the bounds declared on a particular set of type
2698 /// parameters. Should eventually be generalized into a flag list of
2699 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
2700 /// `GenericPredicates` by using the `instantiate` method. Note that this method
2701 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
2702 /// the `GenericPredicates` are expressed in terms of the bound type
2703 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
2704 /// represented a set of bounds for some particular instantiation,
2705 /// meaning that the generic parameters have been substituted with
2710 /// struct Foo<T,U:Bar<T>> { ... }
2712 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
2713 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
2714 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
2715 /// [usize:Bar<isize>]]`.
2717 pub struct InstantiatedPredicates<'tcx> {
2718 pub predicates: VecPerParamSpace<Predicate<'tcx>>,
2721 impl<'tcx> InstantiatedPredicates<'tcx> {
2722 pub fn empty() -> InstantiatedPredicates<'tcx> {
2723 InstantiatedPredicates { predicates: VecPerParamSpace::empty() }
2726 pub fn has_escaping_regions(&self) -> bool {
2727 self.predicates.any(|p| p.has_escaping_regions())
2730 pub fn is_empty(&self) -> bool {
2731 self.predicates.is_empty()
2735 impl<'tcx> TraitRef<'tcx> {
2736 pub fn new(def_id: ast::DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
2737 TraitRef { def_id: def_id, substs: substs }
2740 pub fn self_ty(&self) -> Ty<'tcx> {
2741 self.substs.self_ty().unwrap()
2744 pub fn input_types(&self) -> &[Ty<'tcx>] {
2745 // Select only the "input types" from a trait-reference. For
2746 // now this is all the types that appear in the
2747 // trait-reference, but it should eventually exclude
2748 // associated types.
2749 self.substs.types.as_slice()
2753 /// When type checking, we use the `ParameterEnvironment` to track
2754 /// details about the type/lifetime parameters that are in scope.
2755 /// It primarily stores the bounds information.
2757 /// Note: This information might seem to be redundant with the data in
2758 /// `tcx.ty_param_defs`, but it is not. That table contains the
2759 /// parameter definitions from an "outside" perspective, but this
2760 /// struct will contain the bounds for a parameter as seen from inside
2761 /// the function body. Currently the only real distinction is that
2762 /// bound lifetime parameters are replaced with free ones, but in the
2763 /// future I hope to refine the representation of types so as to make
2764 /// more distinctions clearer.
2766 pub struct ParameterEnvironment<'a, 'tcx:'a> {
2767 pub tcx: &'a ctxt<'tcx>,
2769 /// See `construct_free_substs` for details.
2770 pub free_substs: Substs<'tcx>,
2772 /// Each type parameter has an implicit region bound that
2773 /// indicates it must outlive at least the function body (the user
2774 /// may specify stronger requirements). This field indicates the
2775 /// region of the callee.
2776 pub implicit_region_bound: ty::Region,
2778 /// Obligations that the caller must satisfy. This is basically
2779 /// the set of bounds on the in-scope type parameters, translated
2780 /// into Obligations, and elaborated and normalized.
2781 pub caller_bounds: Vec<ty::Predicate<'tcx>>,
2783 /// Caches the results of trait selection. This cache is used
2784 /// for things that have to do with the parameters in scope.
2785 pub selection_cache: traits::SelectionCache<'tcx>,
2788 impl<'a, 'tcx> ParameterEnvironment<'a, 'tcx> {
2789 pub fn with_caller_bounds(&self,
2790 caller_bounds: Vec<ty::Predicate<'tcx>>)
2791 -> ParameterEnvironment<'a,'tcx>
2793 ParameterEnvironment {
2795 free_substs: self.free_substs.clone(),
2796 implicit_region_bound: self.implicit_region_bound,
2797 caller_bounds: caller_bounds,
2798 selection_cache: traits::SelectionCache::new(),
2802 pub fn for_item(cx: &'a ctxt<'tcx>, id: NodeId) -> ParameterEnvironment<'a, 'tcx> {
2803 match cx.map.find(id) {
2804 Some(ast_map::NodeImplItem(ref impl_item)) => {
2805 match impl_item.node {
2806 ast::ConstImplItem(_, _) => {
2807 let def_id = ast_util::local_def(id);
2808 let scheme = cx.lookup_item_type(def_id);
2809 let predicates = cx.lookup_predicates(def_id);
2810 cx.construct_parameter_environment(impl_item.span,
2815 ast::MethodImplItem(_, ref body) => {
2816 let method_def_id = ast_util::local_def(id);
2817 match cx.impl_or_trait_item(method_def_id) {
2818 MethodTraitItem(ref method_ty) => {
2819 let method_generics = &method_ty.generics;
2820 let method_bounds = &method_ty.predicates;
2821 cx.construct_parameter_environment(
2829 .bug("ParameterEnvironment::for_item(): \
2830 got non-method item from impl method?!")
2834 ast::TypeImplItem(_) => {
2835 cx.sess.bug("ParameterEnvironment::for_item(): \
2836 can't create a parameter environment \
2837 for type impl items")
2839 ast::MacImplItem(_) => cx.sess.bug("unexpanded macro")
2842 Some(ast_map::NodeTraitItem(trait_item)) => {
2843 match trait_item.node {
2844 ast::ConstTraitItem(_, ref default) => {
2847 let def_id = ast_util::local_def(id);
2848 let scheme = cx.lookup_item_type(def_id);
2849 let predicates = cx.lookup_predicates(def_id);
2850 cx.construct_parameter_environment(trait_item.span,
2856 cx.sess.bug("ParameterEnvironment::from_item(): \
2857 can't create a parameter environment \
2858 for const trait items without defaults")
2862 ast::MethodTraitItem(_, None) => {
2863 cx.sess.span_bug(trait_item.span,
2864 "ParameterEnvironment::for_item():
2865 can't create a parameter \
2866 environment for required trait \
2869 ast::MethodTraitItem(_, Some(ref body)) => {
2870 let method_def_id = ast_util::local_def(id);
2871 match cx.impl_or_trait_item(method_def_id) {
2872 MethodTraitItem(ref method_ty) => {
2873 let method_generics = &method_ty.generics;
2874 let method_bounds = &method_ty.predicates;
2875 cx.construct_parameter_environment(
2883 .bug("ParameterEnvironment::for_item(): \
2884 got non-method item from provided \
2889 ast::TypeTraitItem(..) => {
2890 cx.sess.bug("ParameterEnvironment::from_item(): \
2891 can't create a parameter environment \
2892 for type trait items")
2896 Some(ast_map::NodeItem(item)) => {
2898 ast::ItemFn(_, _, _, _, _, ref body) => {
2899 // We assume this is a function.
2900 let fn_def_id = ast_util::local_def(id);
2901 let fn_scheme = cx.lookup_item_type(fn_def_id);
2902 let fn_predicates = cx.lookup_predicates(fn_def_id);
2904 cx.construct_parameter_environment(item.span,
2905 &fn_scheme.generics,
2910 ast::ItemStruct(..) |
2912 ast::ItemConst(..) |
2913 ast::ItemStatic(..) => {
2914 let def_id = ast_util::local_def(id);
2915 let scheme = cx.lookup_item_type(def_id);
2916 let predicates = cx.lookup_predicates(def_id);
2917 cx.construct_parameter_environment(item.span,
2923 cx.sess.span_bug(item.span,
2924 "ParameterEnvironment::from_item():
2925 can't create a parameter \
2926 environment for this kind of item")
2930 Some(ast_map::NodeExpr(..)) => {
2931 // This is a convenience to allow closures to work.
2932 ParameterEnvironment::for_item(cx, cx.map.get_parent(id))
2935 cx.sess.bug(&format!("ParameterEnvironment::from_item(): \
2936 `{}` is not an item",
2937 cx.map.node_to_string(id)))
2942 pub fn can_type_implement_copy(&self, self_type: Ty<'tcx>, span: Span)
2943 -> Result<(),CopyImplementationError> {
2946 // FIXME: (@jroesch) float this code up
2947 let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, Some(self.clone()), false);
2949 let did = match self_type.sty {
2950 ty::TyStruct(struct_did, substs) => {
2951 let fields = tcx.struct_fields(struct_did, substs);
2952 for field in &fields {
2953 if infcx.type_moves_by_default(field.mt.ty, span) {
2954 return Err(FieldDoesNotImplementCopy(field.name))
2959 ty::TyEnum(enum_did, substs) => {
2960 let enum_variants = tcx.enum_variants(enum_did);
2961 for variant in enum_variants.iter() {
2962 for variant_arg_type in &variant.args {
2963 let substd_arg_type =
2964 variant_arg_type.subst(tcx, substs);
2965 if infcx.type_moves_by_default(substd_arg_type, span) {
2966 return Err(VariantDoesNotImplementCopy(variant.name))
2972 _ => return Err(TypeIsStructural),
2975 if tcx.has_dtor(did) {
2976 return Err(TypeHasDestructor)
2983 #[derive(Copy, Clone)]
2984 pub enum CopyImplementationError {
2985 FieldDoesNotImplementCopy(ast::Name),
2986 VariantDoesNotImplementCopy(ast::Name),
2991 /// A "type scheme", in ML terminology, is a type combined with some
2992 /// set of generic types that the type is, well, generic over. In Rust
2993 /// terms, it is the "type" of a fn item or struct -- this type will
2994 /// include various generic parameters that must be substituted when
2995 /// the item/struct is referenced. That is called converting the type
2996 /// scheme to a monotype.
2998 /// - `generics`: the set of type parameters and their bounds
2999 /// - `ty`: the base types, which may reference the parameters defined
3002 /// Note that TypeSchemes are also sometimes called "polytypes" (and
3003 /// in fact this struct used to carry that name, so you may find some
3004 /// stray references in a comment or something). We try to reserve the
3005 /// "poly" prefix to refer to higher-ranked things, as in
3008 /// Note that each item also comes with predicates, see
3009 /// `lookup_predicates`.
3010 #[derive(Clone, Debug)]
3011 pub struct TypeScheme<'tcx> {
3012 pub generics: Generics<'tcx>,
3017 flags TraitFlags: u32 {
3018 const NO_TRAIT_FLAGS = 0,
3019 const HAS_DEFAULT_IMPL = 1 << 0,
3020 const IS_OBJECT_SAFE = 1 << 1,
3021 const OBJECT_SAFETY_VALID = 1 << 2,
3022 const IMPLS_VALID = 1 << 3,
3026 /// As `TypeScheme` but for a trait ref.
3027 pub struct TraitDef<'tcx> {
3028 pub unsafety: ast::Unsafety,
3030 /// If `true`, then this trait had the `#[rustc_paren_sugar]`
3031 /// attribute, indicating that it should be used with `Foo()`
3032 /// sugar. This is a temporary thing -- eventually any trait wil
3033 /// be usable with the sugar (or without it).
3034 pub paren_sugar: bool,
3036 /// Generic type definitions. Note that `Self` is listed in here
3037 /// as having a single bound, the trait itself (e.g., in the trait
3038 /// `Eq`, there is a single bound `Self : Eq`). This is so that
3039 /// default methods get to assume that the `Self` parameters
3040 /// implements the trait.
3041 pub generics: Generics<'tcx>,
3043 pub trait_ref: TraitRef<'tcx>,
3045 /// A list of the associated types defined in this trait. Useful
3046 /// for resolving `X::Foo` type markers.
3047 pub associated_type_names: Vec<ast::Name>,
3049 // Impls of this trait. To allow for quicker lookup, the impls are indexed
3050 // by a simplified version of their Self type: impls with a simplifiable
3051 // Self are stored in nonblanket_impls keyed by it, while all other impls
3052 // are stored in blanket_impls.
3054 /// Impls of the trait.
3055 pub nonblanket_impls: RefCell<
3056 FnvHashMap<fast_reject::SimplifiedType, Vec<DefId>>
3059 /// Blanket impls associated with the trait.
3060 pub blanket_impls: RefCell<Vec<DefId>>,
3063 pub flags: Cell<TraitFlags>
3066 impl<'tcx> TraitDef<'tcx> {
3067 // returns None if not yet calculated
3068 pub fn object_safety(&self) -> Option<bool> {
3069 if self.flags.get().intersects(TraitFlags::OBJECT_SAFETY_VALID) {
3070 Some(self.flags.get().intersects(TraitFlags::IS_OBJECT_SAFE))
3076 pub fn set_object_safety(&self, is_safe: bool) {
3077 assert!(self.object_safety().map(|cs| cs == is_safe).unwrap_or(true));
3079 self.flags.get() | if is_safe {
3080 TraitFlags::OBJECT_SAFETY_VALID | TraitFlags::IS_OBJECT_SAFE
3082 TraitFlags::OBJECT_SAFETY_VALID
3087 /// Records a trait-to-implementation mapping.
3088 pub fn record_impl(&self,
3091 impl_trait_ref: TraitRef<'tcx>) {
3092 debug!("TraitDef::record_impl for {:?}, from {:?}",
3093 self, impl_trait_ref);
3095 // We don't want to borrow_mut after we already populated all impls,
3096 // so check if an impl is present with an immutable borrow first.
3097 if let Some(sty) = fast_reject::simplify_type(tcx,
3098 impl_trait_ref.self_ty(), false) {
3099 if let Some(is) = self.nonblanket_impls.borrow().get(&sty) {
3100 if is.contains(&impl_def_id) {
3101 return // duplicate - skip
3105 self.nonblanket_impls.borrow_mut().entry(sty).or_insert(vec![]).push(impl_def_id)
3107 if self.blanket_impls.borrow().contains(&impl_def_id) {
3108 return // duplicate - skip
3110 self.blanket_impls.borrow_mut().push(impl_def_id)
3115 pub fn for_each_impl<F: FnMut(DefId)>(&self, tcx: &ctxt<'tcx>, mut f: F) {
3116 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
3118 for &impl_def_id in self.blanket_impls.borrow().iter() {
3122 for v in self.nonblanket_impls.borrow().values() {
3123 for &impl_def_id in v {
3129 pub fn for_each_relevant_impl<F: FnMut(DefId)>(&self,
3134 tcx.populate_implementations_for_trait_if_necessary(self.trait_ref.def_id);
3136 for &impl_def_id in self.blanket_impls.borrow().iter() {
3140 if let Some(simp) = fast_reject::simplify_type(tcx, self_ty, false) {
3141 if let Some(impls) = self.nonblanket_impls.borrow().get(&simp) {
3142 for &impl_def_id in impls {
3145 return; // we don't need to process the other non-blanket impls
3149 for v in self.nonblanket_impls.borrow().values() {
3150 for &impl_def_id in v {
3158 /// Records the substitutions used to translate the polytype for an
3159 /// item into the monotype of an item reference.
3161 pub struct ItemSubsts<'tcx> {
3162 pub substs: Substs<'tcx>,
3165 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Debug, RustcEncodable, RustcDecodable)]
3166 pub enum ClosureKind {
3167 // Warning: Ordering is significant here! The ordering is chosen
3168 // because the trait Fn is a subtrait of FnMut and so in turn, and
3169 // hence we order it so that Fn < FnMut < FnOnce.
3176 pub fn trait_did(&self, cx: &ctxt) -> ast::DefId {
3177 let result = match *self {
3178 FnClosureKind => cx.lang_items.require(FnTraitLangItem),
3179 FnMutClosureKind => {
3180 cx.lang_items.require(FnMutTraitLangItem)
3182 FnOnceClosureKind => {
3183 cx.lang_items.require(FnOnceTraitLangItem)
3187 Ok(trait_did) => trait_did,
3188 Err(err) => cx.sess.fatal(&err[..]),
3192 /// True if this a type that impls this closure kind
3193 /// must also implement `other`.
3194 pub fn extends(self, other: ty::ClosureKind) -> bool {
3195 match (self, other) {
3196 (FnClosureKind, FnClosureKind) => true,
3197 (FnClosureKind, FnMutClosureKind) => true,
3198 (FnClosureKind, FnOnceClosureKind) => true,
3199 (FnMutClosureKind, FnMutClosureKind) => true,
3200 (FnMutClosureKind, FnOnceClosureKind) => true,
3201 (FnOnceClosureKind, FnOnceClosureKind) => true,
3207 impl<'tcx> CommonTypes<'tcx> {
3208 fn new(arena: &'tcx TypedArena<TyS<'tcx>>,
3209 interner: &RefCell<FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>>)
3210 -> CommonTypes<'tcx>
3212 let mk = |sty| ctxt::intern_ty(arena, interner, sty);
3217 isize: mk(TyInt(ast::TyIs)),
3218 i8: mk(TyInt(ast::TyI8)),
3219 i16: mk(TyInt(ast::TyI16)),
3220 i32: mk(TyInt(ast::TyI32)),
3221 i64: mk(TyInt(ast::TyI64)),
3222 usize: mk(TyUint(ast::TyUs)),
3223 u8: mk(TyUint(ast::TyU8)),
3224 u16: mk(TyUint(ast::TyU16)),
3225 u32: mk(TyUint(ast::TyU32)),
3226 u64: mk(TyUint(ast::TyU64)),
3227 f32: mk(TyFloat(ast::TyF32)),
3228 f64: mk(TyFloat(ast::TyF64)),
3233 struct FlagComputation {
3236 // maximum depth of any bound region that we have seen thus far
3240 impl FlagComputation {
3241 fn new() -> FlagComputation {
3242 FlagComputation { flags: TypeFlags::empty(), depth: 0 }
3245 fn for_sty(st: &TypeVariants) -> FlagComputation {
3246 let mut result = FlagComputation::new();
3251 fn add_flags(&mut self, flags: TypeFlags) {
3252 self.flags = self.flags | (flags & TypeFlags::NOMINAL_FLAGS);
3255 fn add_depth(&mut self, depth: u32) {
3256 if depth > self.depth {
3261 /// Adds the flags/depth from a set of types that appear within the current type, but within a
3263 fn add_bound_computation(&mut self, computation: &FlagComputation) {
3264 self.add_flags(computation.flags);
3266 // The types that contributed to `computation` occurred within
3267 // a region binder, so subtract one from the region depth
3268 // within when adding the depth to `self`.
3269 let depth = computation.depth;
3271 self.add_depth(depth - 1);
3275 fn add_sty(&mut self, st: &TypeVariants) {
3285 // You might think that we could just return TyError for
3286 // any type containing TyError as a component, and get
3287 // rid of the TypeFlags::HAS_TY_ERR flag -- likewise for ty_bot (with
3288 // the exception of function types that return bot).
3289 // But doing so caused sporadic memory corruption, and
3290 // neither I (tjc) nor nmatsakis could figure out why,
3291 // so we're doing it this way.
3293 self.add_flags(TypeFlags::HAS_TY_ERR)
3296 &TyParam(ref p) => {
3297 self.add_flags(TypeFlags::HAS_LOCAL_NAMES);
3298 if p.space == subst::SelfSpace {
3299 self.add_flags(TypeFlags::HAS_SELF);
3301 self.add_flags(TypeFlags::HAS_PARAMS);
3305 &TyClosure(_, ref substs) => {
3306 self.add_flags(TypeFlags::HAS_TY_CLOSURE);
3307 self.add_flags(TypeFlags::HAS_LOCAL_NAMES);
3308 self.add_substs(&substs.func_substs);
3309 self.add_tys(&substs.upvar_tys);
3313 self.add_flags(TypeFlags::HAS_LOCAL_NAMES); // it might, right?
3314 self.add_flags(TypeFlags::HAS_TY_INFER)
3317 &TyEnum(_, substs) | &TyStruct(_, substs) => {
3318 self.add_substs(substs);
3321 &TyProjection(ref data) => {
3322 self.add_flags(TypeFlags::HAS_PROJECTION);
3323 self.add_projection_ty(data);
3326 &TyTrait(box TraitTy { ref principal, ref bounds }) => {
3327 let mut computation = FlagComputation::new();
3328 computation.add_substs(principal.0.substs);
3329 for projection_bound in &bounds.projection_bounds {
3330 let mut proj_computation = FlagComputation::new();
3331 proj_computation.add_projection_predicate(&projection_bound.0);
3332 self.add_bound_computation(&proj_computation);
3334 self.add_bound_computation(&computation);
3336 self.add_bounds(bounds);
3339 &TyBox(tt) | &TyArray(tt, _) | &TySlice(tt) => {
3343 &TyRawPtr(ref m) => {
3347 &TyRef(r, ref m) => {
3348 self.add_region(*r);
3352 &TyTuple(ref ts) => {
3353 self.add_tys(&ts[..]);
3356 &TyBareFn(_, ref f) => {
3357 self.add_fn_sig(&f.sig);
3362 fn add_ty(&mut self, ty: Ty) {
3363 self.add_flags(ty.flags.get());
3364 self.add_depth(ty.region_depth);
3367 fn add_tys(&mut self, tys: &[Ty]) {
3373 fn add_fn_sig(&mut self, fn_sig: &PolyFnSig) {
3374 let mut computation = FlagComputation::new();
3376 computation.add_tys(&fn_sig.0.inputs);
3378 if let ty::FnConverging(output) = fn_sig.0.output {
3379 computation.add_ty(output);
3382 self.add_bound_computation(&computation);
3385 fn add_region(&mut self, r: Region) {
3387 ty::ReInfer(_) => { self.add_flags(TypeFlags::HAS_RE_INFER); }
3388 ty::ReLateBound(debruijn, _) => { self.add_depth(debruijn.depth); }
3389 ty::ReEarlyBound(..) => { self.add_flags(TypeFlags::HAS_RE_EARLY_BOUND); }
3391 _ => { self.add_flags(TypeFlags::HAS_FREE_REGIONS); }
3395 self.add_flags(TypeFlags::HAS_LOCAL_NAMES);
3399 fn add_projection_predicate(&mut self, projection_predicate: &ProjectionPredicate) {
3400 self.add_projection_ty(&projection_predicate.projection_ty);
3401 self.add_ty(projection_predicate.ty);
3404 fn add_projection_ty(&mut self, projection_ty: &ProjectionTy) {
3405 self.add_substs(projection_ty.trait_ref.substs);
3408 fn add_substs(&mut self, substs: &Substs) {
3409 self.add_tys(substs.types.as_slice());
3410 match substs.regions {
3411 subst::ErasedRegions => {}
3412 subst::NonerasedRegions(ref regions) => {
3420 fn add_bounds(&mut self, bounds: &ExistentialBounds) {
3421 self.add_region(bounds.region_bound);
3425 impl<'tcx> ctxt<'tcx> {
3426 /// Create a type context and call the closure with a `&ty::ctxt` reference
3427 /// to the context. The closure enforces that the type context and any interned
3428 /// value (types, substs, etc.) can only be used while `ty::tls` has a valid
3429 /// reference to the context, to allow formatting values that need it.
3430 pub fn create_and_enter<F, R>(s: Session,
3431 arenas: &'tcx CtxtArenas<'tcx>,
3433 named_region_map: resolve_lifetime::NamedRegionMap,
3434 map: ast_map::Map<'tcx>,
3435 freevars: RefCell<FreevarMap>,
3436 region_maps: RegionMaps,
3437 lang_items: middle::lang_items::LanguageItems,
3438 stability: stability::Index<'tcx>,
3439 f: F) -> (Session, R)
3440 where F: FnOnce(&ctxt<'tcx>) -> R
3442 let interner = RefCell::new(FnvHashMap());
3443 let common_types = CommonTypes::new(&arenas.type_, &interner);
3448 substs_interner: RefCell::new(FnvHashMap()),
3449 bare_fn_interner: RefCell::new(FnvHashMap()),
3450 region_interner: RefCell::new(FnvHashMap()),
3451 stability_interner: RefCell::new(FnvHashMap()),
3452 types: common_types,
3453 named_region_map: named_region_map,
3454 region_maps: region_maps,
3455 free_region_maps: RefCell::new(FnvHashMap()),
3456 item_variance_map: RefCell::new(DefIdMap()),
3457 variance_computed: Cell::new(false),
3460 tables: RefCell::new(Tables::empty()),
3461 impl_trait_refs: RefCell::new(DefIdMap()),
3462 trait_defs: RefCell::new(DefIdMap()),
3463 predicates: RefCell::new(DefIdMap()),
3464 super_predicates: RefCell::new(DefIdMap()),
3465 fulfilled_predicates: RefCell::new(traits::FulfilledPredicates::new()),
3468 tcache: RefCell::new(DefIdMap()),
3469 rcache: RefCell::new(FnvHashMap()),
3470 tc_cache: RefCell::new(FnvHashMap()),
3471 ast_ty_to_ty_cache: RefCell::new(NodeMap()),
3472 enum_var_cache: RefCell::new(DefIdMap()),
3473 impl_or_trait_items: RefCell::new(DefIdMap()),
3474 trait_item_def_ids: RefCell::new(DefIdMap()),
3475 trait_items_cache: RefCell::new(DefIdMap()),
3476 ty_param_defs: RefCell::new(NodeMap()),
3477 normalized_cache: RefCell::new(FnvHashMap()),
3478 lang_items: lang_items,
3479 provided_method_sources: RefCell::new(DefIdMap()),
3480 struct_fields: RefCell::new(DefIdMap()),
3481 destructor_for_type: RefCell::new(DefIdMap()),
3482 destructors: RefCell::new(DefIdSet()),
3483 inherent_impls: RefCell::new(DefIdMap()),
3484 impl_items: RefCell::new(DefIdMap()),
3485 used_unsafe: RefCell::new(NodeSet()),
3486 used_mut_nodes: RefCell::new(NodeSet()),
3487 populated_external_types: RefCell::new(DefIdSet()),
3488 populated_external_primitive_impls: RefCell::new(DefIdSet()),
3489 extern_const_statics: RefCell::new(DefIdMap()),
3490 extern_const_variants: RefCell::new(DefIdMap()),
3491 extern_const_fns: RefCell::new(DefIdMap()),
3492 dependency_formats: RefCell::new(FnvHashMap()),
3493 node_lint_levels: RefCell::new(FnvHashMap()),
3494 transmute_restrictions: RefCell::new(Vec::new()),
3495 stability: RefCell::new(stability),
3496 selection_cache: traits::SelectionCache::new(),
3497 repr_hint_cache: RefCell::new(DefIdMap()),
3498 const_qualif_map: RefCell::new(NodeMap()),
3499 custom_coerce_unsized_kinds: RefCell::new(DefIdMap()),
3500 cast_kinds: RefCell::new(NodeMap()),
3504 // Type constructors
3506 pub fn mk_substs(&self, substs: Substs<'tcx>) -> &'tcx Substs<'tcx> {
3507 if let Some(substs) = self.substs_interner.borrow().get(&substs) {
3511 let substs = self.arenas.substs.alloc(substs);
3512 self.substs_interner.borrow_mut().insert(substs, substs);
3516 /// Create an unsafe fn ty based on a safe fn ty.
3517 pub fn safe_to_unsafe_fn_ty(&self, bare_fn: &BareFnTy<'tcx>) -> Ty<'tcx> {
3518 assert_eq!(bare_fn.unsafety, ast::Unsafety::Normal);
3519 let unsafe_fn_ty_a = self.mk_bare_fn(ty::BareFnTy {
3520 unsafety: ast::Unsafety::Unsafe,
3522 sig: bare_fn.sig.clone()
3524 self.mk_fn(None, unsafe_fn_ty_a)
3527 pub fn mk_bare_fn(&self, bare_fn: BareFnTy<'tcx>) -> &'tcx BareFnTy<'tcx> {
3528 if let Some(bare_fn) = self.bare_fn_interner.borrow().get(&bare_fn) {
3532 let bare_fn = self.arenas.bare_fn.alloc(bare_fn);
3533 self.bare_fn_interner.borrow_mut().insert(bare_fn, bare_fn);
3537 pub fn mk_region(&self, region: Region) -> &'tcx Region {
3538 if let Some(region) = self.region_interner.borrow().get(®ion) {
3542 let region = self.arenas.region.alloc(region);
3543 self.region_interner.borrow_mut().insert(region, region);
3547 pub fn closure_kind(&self, def_id: ast::DefId) -> ty::ClosureKind {
3548 *self.tables.borrow().closure_kinds.get(&def_id).unwrap()
3551 pub fn closure_type(&self,
3553 substs: &ClosureSubsts<'tcx>)
3554 -> ty::ClosureTy<'tcx>
3556 self.tables.borrow().closure_tys.get(&def_id).unwrap().subst(self, &substs.func_substs)
3559 pub fn type_parameter_def(&self,
3560 node_id: ast::NodeId)
3561 -> TypeParameterDef<'tcx>
3563 self.ty_param_defs.borrow().get(&node_id).unwrap().clone()
3566 pub fn pat_contains_ref_binding(&self, pat: &ast::Pat) -> Option<ast::Mutability> {
3567 pat_util::pat_contains_ref_binding(&self.def_map, pat)
3570 pub fn arm_contains_ref_binding(&self, arm: &ast::Arm) -> Option<ast::Mutability> {
3571 pat_util::arm_contains_ref_binding(&self.def_map, arm)
3574 fn intern_ty(type_arena: &'tcx TypedArena<TyS<'tcx>>,
3575 interner: &RefCell<FnvHashMap<InternedTy<'tcx>, Ty<'tcx>>>,
3576 st: TypeVariants<'tcx>)
3578 let ty: Ty /* don't be &mut TyS */ = {
3579 let mut interner = interner.borrow_mut();
3580 match interner.get(&st) {
3581 Some(ty) => return *ty,
3585 let flags = FlagComputation::for_sty(&st);
3588 () => type_arena.alloc(TyS { sty: st,
3589 flags: Cell::new(flags.flags),
3590 region_depth: flags.depth, }),
3593 interner.insert(InternedTy { ty: ty }, ty);
3597 debug!("Interned type: {:?} Pointer: {:?}",
3598 ty, ty as *const TyS);
3602 // Interns a type/name combination, stores the resulting box in cx.interner,
3603 // and returns the box as cast to an unsafe ptr (see comments for Ty above).
3604 pub fn mk_ty(&self, st: TypeVariants<'tcx>) -> Ty<'tcx> {
3605 ctxt::intern_ty(&self.arenas.type_, &self.interner, st)
3608 pub fn mk_mach_int(&self, tm: ast::IntTy) -> Ty<'tcx> {
3610 ast::TyIs => self.types.isize,
3611 ast::TyI8 => self.types.i8,
3612 ast::TyI16 => self.types.i16,
3613 ast::TyI32 => self.types.i32,
3614 ast::TyI64 => self.types.i64,
3618 pub fn mk_mach_uint(&self, tm: ast::UintTy) -> Ty<'tcx> {
3620 ast::TyUs => self.types.usize,
3621 ast::TyU8 => self.types.u8,
3622 ast::TyU16 => self.types.u16,
3623 ast::TyU32 => self.types.u32,
3624 ast::TyU64 => self.types.u64,
3628 pub fn mk_mach_float(&self, tm: ast::FloatTy) -> Ty<'tcx> {
3630 ast::TyF32 => self.types.f32,
3631 ast::TyF64 => self.types.f64,
3635 pub fn mk_str(&self) -> Ty<'tcx> {
3639 pub fn mk_static_str(&self) -> Ty<'tcx> {
3640 self.mk_imm_ref(self.mk_region(ty::ReStatic), self.mk_str())
3643 pub fn mk_enum(&self, did: ast::DefId, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
3644 // take a copy of substs so that we own the vectors inside
3645 self.mk_ty(TyEnum(did, substs))
3648 pub fn mk_box(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3649 self.mk_ty(TyBox(ty))
3652 pub fn mk_ptr(&self, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
3653 self.mk_ty(TyRawPtr(tm))
3656 pub fn mk_ref(&self, r: &'tcx Region, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
3657 self.mk_ty(TyRef(r, tm))
3660 pub fn mk_mut_ref(&self, r: &'tcx Region, ty: Ty<'tcx>) -> Ty<'tcx> {
3661 self.mk_ref(r, TypeAndMut {ty: ty, mutbl: ast::MutMutable})
3664 pub fn mk_imm_ref(&self, r: &'tcx Region, ty: Ty<'tcx>) -> Ty<'tcx> {
3665 self.mk_ref(r, TypeAndMut {ty: ty, mutbl: ast::MutImmutable})
3668 pub fn mk_mut_ptr(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3669 self.mk_ptr(TypeAndMut {ty: ty, mutbl: ast::MutMutable})
3672 pub fn mk_imm_ptr(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3673 self.mk_ptr(TypeAndMut {ty: ty, mutbl: ast::MutImmutable})
3676 pub fn mk_nil_ptr(&self) -> Ty<'tcx> {
3677 self.mk_imm_ptr(self.mk_nil())
3680 pub fn mk_array(&self, ty: Ty<'tcx>, n: usize) -> Ty<'tcx> {
3681 self.mk_ty(TyArray(ty, n))
3684 pub fn mk_slice(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
3685 self.mk_ty(TySlice(ty))
3688 pub fn mk_tup(&self, ts: Vec<Ty<'tcx>>) -> Ty<'tcx> {
3689 self.mk_ty(TyTuple(ts))
3692 pub fn mk_nil(&self) -> Ty<'tcx> {
3693 self.mk_tup(Vec::new())
3696 pub fn mk_bool(&self) -> Ty<'tcx> {
3701 opt_def_id: Option<ast::DefId>,
3702 fty: &'tcx BareFnTy<'tcx>) -> Ty<'tcx> {
3703 self.mk_ty(TyBareFn(opt_def_id, fty))
3706 pub fn mk_ctor_fn(&self,
3708 input_tys: &[Ty<'tcx>],
3709 output: Ty<'tcx>) -> Ty<'tcx> {
3710 let input_args = input_tys.iter().cloned().collect();
3711 self.mk_fn(Some(def_id), self.mk_bare_fn(BareFnTy {
3712 unsafety: ast::Unsafety::Normal,
3714 sig: ty::Binder(FnSig {
3716 output: ty::FnConverging(output),
3722 pub fn mk_trait(&self,
3723 principal: ty::PolyTraitRef<'tcx>,
3724 bounds: ExistentialBounds<'tcx>)
3727 assert!(bound_list_is_sorted(&bounds.projection_bounds));
3729 let inner = box TraitTy {
3730 principal: principal,
3733 self.mk_ty(TyTrait(inner))
3736 pub fn mk_projection(&self,
3737 trait_ref: TraitRef<'tcx>,
3738 item_name: ast::Name)
3740 // take a copy of substs so that we own the vectors inside
3741 let inner = ProjectionTy { trait_ref: trait_ref, item_name: item_name };
3742 self.mk_ty(TyProjection(inner))
3745 pub fn mk_struct(&self, struct_id: ast::DefId,
3746 substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
3747 // take a copy of substs so that we own the vectors inside
3748 self.mk_ty(TyStruct(struct_id, substs))
3751 pub fn mk_closure(&self,
3752 closure_id: ast::DefId,
3753 substs: &'tcx Substs<'tcx>,
3756 self.mk_closure_from_closure_substs(closure_id, Box::new(ClosureSubsts {
3757 func_substs: substs,
3762 pub fn mk_closure_from_closure_substs(&self,
3763 closure_id: ast::DefId,
3764 closure_substs: Box<ClosureSubsts<'tcx>>)
3766 self.mk_ty(TyClosure(closure_id, closure_substs))
3769 pub fn mk_var(&self, v: TyVid) -> Ty<'tcx> {
3770 self.mk_infer(TyVar(v))
3773 pub fn mk_int_var(&self, v: IntVid) -> Ty<'tcx> {
3774 self.mk_infer(IntVar(v))
3777 pub fn mk_float_var(&self, v: FloatVid) -> Ty<'tcx> {
3778 self.mk_infer(FloatVar(v))
3781 pub fn mk_infer(&self, it: InferTy) -> Ty<'tcx> {
3782 self.mk_ty(TyInfer(it))
3785 pub fn mk_param(&self,
3786 space: subst::ParamSpace,
3788 name: ast::Name) -> Ty<'tcx> {
3789 self.mk_ty(TyParam(ParamTy { space: space, idx: index, name: name }))
3792 pub fn mk_self_type(&self) -> Ty<'tcx> {
3793 self.mk_param(subst::SelfSpace, 0, special_idents::type_self.name)
3796 pub fn mk_param_from_def(&self, def: &TypeParameterDef) -> Ty<'tcx> {
3797 self.mk_param(def.space, def.index, def.name)
3801 fn bound_list_is_sorted(bounds: &[ty::PolyProjectionPredicate]) -> bool {
3802 bounds.is_empty() ||
3803 bounds[1..].iter().enumerate().all(
3804 |(index, bound)| bounds[index].sort_key() <= bound.sort_key())
3807 pub fn sort_bounds_list(bounds: &mut [ty::PolyProjectionPredicate]) {
3808 bounds.sort_by(|a, b| a.sort_key().cmp(&b.sort_key()))
3811 impl<'tcx> TyS<'tcx> {
3812 /// Iterator that walks `self` and any types reachable from
3813 /// `self`, in depth-first order. Note that just walks the types
3814 /// that appear in `self`, it does not descend into the fields of
3815 /// structs or variants. For example:
3818 /// isize => { isize }
3819 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
3820 /// [isize] => { [isize], isize }
3822 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
3823 TypeWalker::new(self)
3826 /// Iterator that walks the immediate children of `self`. Hence
3827 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
3828 /// (but not `i32`, like `walk`).
3829 pub fn walk_shallow(&'tcx self) -> IntoIter<Ty<'tcx>> {
3830 ty_walk::walk_shallow(self)
3833 pub fn as_opt_param_ty(&self) -> Option<ty::ParamTy> {
3835 ty::TyParam(ref d) => Some(d.clone()),
3840 pub fn is_param(&self, space: ParamSpace, index: u32) -> bool {
3842 ty::TyParam(ref data) => data.space == space && data.idx == index,
3847 /// Walks `ty` and any types appearing within `ty`, invoking the
3848 /// callback `f` on each type. If the callback returns false, then the
3849 /// children of the current type are ignored.
3851 /// Note: prefer `ty.walk()` where possible.
3852 pub fn maybe_walk<F>(&'tcx self, mut f: F)
3853 where F : FnMut(Ty<'tcx>) -> bool
3855 let mut walker = self.walk();
3856 while let Some(ty) = walker.next() {
3858 walker.skip_current_subtree();
3865 pub fn new(space: subst::ParamSpace,
3869 ParamTy { space: space, idx: index, name: name }
3872 pub fn for_self() -> ParamTy {
3873 ParamTy::new(subst::SelfSpace, 0, special_idents::type_self.name)
3876 pub fn for_def(def: &TypeParameterDef) -> ParamTy {
3877 ParamTy::new(def.space, def.index, def.name)
3880 pub fn to_ty<'tcx>(self, tcx: &ctxt<'tcx>) -> Ty<'tcx> {
3881 tcx.mk_param(self.space, self.idx, self.name)
3884 pub fn is_self(&self) -> bool {
3885 self.space == subst::SelfSpace && self.idx == 0
3889 impl<'tcx> ItemSubsts<'tcx> {
3890 pub fn empty() -> ItemSubsts<'tcx> {
3891 ItemSubsts { substs: Substs::empty() }
3894 pub fn is_noop(&self) -> bool {
3895 self.substs.is_noop()
3900 impl<'tcx> TyS<'tcx> {
3901 pub fn is_nil(&self) -> bool {
3903 TyTuple(ref tys) => tys.is_empty(),
3908 pub fn is_empty(&self, cx: &ctxt) -> bool {
3910 TyEnum(did, _) => cx.enum_variants(did).is_empty(),
3915 pub fn is_ty_var(&self) -> bool {
3917 TyInfer(TyVar(_)) => true,
3922 pub fn is_bool(&self) -> bool { self.sty == TyBool }
3924 pub fn is_self(&self) -> bool {
3926 TyParam(ref p) => p.space == subst::SelfSpace,
3931 fn is_slice(&self) -> bool {
3933 TyRawPtr(mt) | TyRef(_, mt) => match mt.ty.sty {
3934 TySlice(_) | TyStr => true,
3941 pub fn is_structural(&self) -> bool {
3943 TyStruct(..) | TyTuple(_) | TyEnum(..) |
3944 TyArray(..) | TyClosure(..) => true,
3945 _ => self.is_slice() | self.is_trait()
3949 pub fn is_simd(&self, cx: &ctxt) -> bool {
3951 TyStruct(did, _) => cx.lookup_simd(did),
3956 pub fn sequence_element_type(&self, cx: &ctxt<'tcx>) -> Ty<'tcx> {
3958 TyArray(ty, _) | TySlice(ty) => ty,
3959 TyStr => cx.mk_mach_uint(ast::TyU8),
3960 _ => cx.sess.bug(&format!("sequence_element_type called on non-sequence value: {}",
3965 pub fn simd_type(&self, cx: &ctxt<'tcx>) -> Ty<'tcx> {
3967 TyStruct(did, substs) => {
3968 let fields = cx.lookup_struct_fields(did);
3969 cx.lookup_field_type(did, fields[0].id, substs)
3971 _ => panic!("simd_type called on invalid type")
3975 pub fn simd_size(&self, cx: &ctxt) -> usize {
3977 TyStruct(did, _) => {
3978 cx.lookup_struct_fields(did).len()
3980 _ => panic!("simd_size called on invalid type")
3984 pub fn is_region_ptr(&self) -> bool {
3991 pub fn is_unsafe_ptr(&self) -> bool {
3993 TyRawPtr(_) => return true,
3998 pub fn is_unique(&self) -> bool {
4006 A scalar type is one that denotes an atomic datum, with no sub-components.
4007 (A TyRawPtr is scalar because it represents a non-managed pointer, so its
4008 contents are abstract to rustc.)
4010 pub fn is_scalar(&self) -> bool {
4012 TyBool | TyChar | TyInt(_) | TyFloat(_) | TyUint(_) |
4013 TyInfer(IntVar(_)) | TyInfer(FloatVar(_)) |
4014 TyBareFn(..) | TyRawPtr(_) => true,
4019 /// Returns true if this type is a floating point type and false otherwise.
4020 pub fn is_floating_point(&self) -> bool {
4023 TyInfer(FloatVar(_)) => true,
4028 pub fn ty_to_def_id(&self) -> Option<ast::DefId> {
4030 TyTrait(ref tt) => Some(tt.principal_def_id()),
4033 TyClosure(id, _) => Some(id),
4039 /// Type contents is how the type checker reasons about kinds.
4040 /// They track what kinds of things are found within a type. You can
4041 /// think of them as kind of an "anti-kind". They track the kinds of values
4042 /// and thinks that are contained in types. Having a larger contents for
4043 /// a type tends to rule that type *out* from various kinds. For example,
4044 /// a type that contains a reference is not sendable.
4046 /// The reason we compute type contents and not kinds is that it is
4047 /// easier for me (nmatsakis) to think about what is contained within
4048 /// a type than to think about what is *not* contained within a type.
4049 #[derive(Clone, Copy)]
4050 pub struct TypeContents {
4054 macro_rules! def_type_content_sets {
4055 (mod $mname:ident { $($name:ident = $bits:expr),+ }) => {
4056 #[allow(non_snake_case)]
4058 use middle::ty::TypeContents;
4060 #[allow(non_upper_case_globals)]
4061 pub const $name: TypeContents = TypeContents { bits: $bits };
4067 def_type_content_sets! {
4069 None = 0b0000_0000__0000_0000__0000,
4071 // Things that are interior to the value (first nibble):
4072 InteriorUnsafe = 0b0000_0000__0000_0000__0010,
4073 InteriorParam = 0b0000_0000__0000_0000__0100,
4074 // InteriorAll = 0b00000000__00000000__1111,
4076 // Things that are owned by the value (second and third nibbles):
4077 OwnsOwned = 0b0000_0000__0000_0001__0000,
4078 OwnsDtor = 0b0000_0000__0000_0010__0000,
4079 OwnsAll = 0b0000_0000__1111_1111__0000,
4081 // Things that mean drop glue is necessary
4082 NeedsDrop = 0b0000_0000__0000_0111__0000,
4085 All = 0b1111_1111__1111_1111__1111
4090 pub fn when(&self, cond: bool) -> TypeContents {
4091 if cond {*self} else {TC::None}
4094 pub fn intersects(&self, tc: TypeContents) -> bool {
4095 (self.bits & tc.bits) != 0
4098 pub fn owns_owned(&self) -> bool {
4099 self.intersects(TC::OwnsOwned)
4102 pub fn interior_param(&self) -> bool {
4103 self.intersects(TC::InteriorParam)
4106 pub fn interior_unsafe(&self) -> bool {
4107 self.intersects(TC::InteriorUnsafe)
4110 pub fn needs_drop(&self, _: &ctxt) -> bool {
4111 self.intersects(TC::NeedsDrop)
4114 /// Includes only those bits that still apply when indirected through a `Box` pointer
4115 pub fn owned_pointer(&self) -> TypeContents {
4116 TC::OwnsOwned | (*self & TC::OwnsAll)
4119 pub fn union<T, F>(v: &[T], mut f: F) -> TypeContents where
4120 F: FnMut(&T) -> TypeContents,
4122 v.iter().fold(TC::None, |tc, ty| tc | f(ty))
4125 pub fn has_dtor(&self) -> bool {
4126 self.intersects(TC::OwnsDtor)
4130 impl ops::BitOr for TypeContents {
4131 type Output = TypeContents;
4133 fn bitor(self, other: TypeContents) -> TypeContents {
4134 TypeContents {bits: self.bits | other.bits}
4138 impl ops::BitAnd for TypeContents {
4139 type Output = TypeContents;
4141 fn bitand(self, other: TypeContents) -> TypeContents {
4142 TypeContents {bits: self.bits & other.bits}
4146 impl ops::Sub for TypeContents {
4147 type Output = TypeContents;
4149 fn sub(self, other: TypeContents) -> TypeContents {
4150 TypeContents {bits: self.bits & !other.bits}
4154 impl fmt::Debug for TypeContents {
4155 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
4156 write!(f, "TypeContents({:b})", self.bits)
4160 impl<'tcx> TyS<'tcx> {
4161 pub fn type_contents(&'tcx self, cx: &ctxt<'tcx>) -> TypeContents {
4162 return memoized(&cx.tc_cache, self, |ty| {
4163 tc_ty(cx, ty, &mut FnvHashMap())
4166 fn tc_ty<'tcx>(cx: &ctxt<'tcx>,
4168 cache: &mut FnvHashMap<Ty<'tcx>, TypeContents>) -> TypeContents
4170 // Subtle: Note that we are *not* using cx.tc_cache here but rather a
4171 // private cache for this walk. This is needed in the case of cyclic
4174 // struct List { next: Box<Option<List>>, ... }
4176 // When computing the type contents of such a type, we wind up deeply
4177 // recursing as we go. So when we encounter the recursive reference
4178 // to List, we temporarily use TC::None as its contents. Later we'll
4179 // patch up the cache with the correct value, once we've computed it
4180 // (this is basically a co-inductive process, if that helps). So in
4181 // the end we'll compute TC::OwnsOwned, in this case.
4183 // The problem is, as we are doing the computation, we will also
4184 // compute an *intermediate* contents for, e.g., Option<List> of
4185 // TC::None. This is ok during the computation of List itself, but if
4186 // we stored this intermediate value into cx.tc_cache, then later
4187 // requests for the contents of Option<List> would also yield TC::None
4188 // which is incorrect. This value was computed based on the crutch
4189 // value for the type contents of list. The correct value is
4190 // TC::OwnsOwned. This manifested as issue #4821.
4191 match cache.get(&ty) {
4192 Some(tc) => { return *tc; }
4195 match cx.tc_cache.borrow().get(&ty) { // Must check both caches!
4196 Some(tc) => { return *tc; }
4199 cache.insert(ty, TC::None);
4201 let result = match ty.sty {
4202 // usize and isize are ffi-unsafe
4203 TyUint(ast::TyUs) | TyInt(ast::TyIs) => {
4207 // Scalar and unique types are sendable, and durable
4208 TyInfer(ty::FreshIntTy(_)) | TyInfer(ty::FreshFloatTy(_)) |
4209 TyBool | TyInt(_) | TyUint(_) | TyFloat(_) |
4210 TyBareFn(..) | ty::TyChar => {
4215 tc_ty(cx, typ, cache).owned_pointer()
4219 TC::All - TC::InteriorParam
4231 tc_ty(cx, ty, cache)
4235 tc_ty(cx, ty, cache)
4239 TyStruct(did, substs) => {
4240 let flds = cx.struct_fields(did, substs);
4242 TypeContents::union(&flds[..],
4243 |f| tc_ty(cx, f.mt.ty, cache));
4245 if cx.has_dtor(did) {
4246 res = res | TC::OwnsDtor;
4248 apply_lang_items(cx, did, res)
4251 TyClosure(_, ref substs) => {
4252 TypeContents::union(&substs.upvar_tys, |ty| tc_ty(cx, &ty, cache))
4255 TyTuple(ref tys) => {
4256 TypeContents::union(&tys[..],
4257 |ty| tc_ty(cx, *ty, cache))
4260 TyEnum(did, substs) => {
4261 let variants = cx.substd_enum_variants(did, substs);
4263 TypeContents::union(&variants[..], |variant| {
4264 TypeContents::union(&variant.args,
4266 tc_ty(cx, *arg_ty, cache)
4270 if cx.has_dtor(did) {
4271 res = res | TC::OwnsDtor;
4274 apply_lang_items(cx, did, res)
4284 cx.sess.bug("asked to compute contents of error type");
4288 cache.insert(ty, result);
4292 fn apply_lang_items(cx: &ctxt, did: ast::DefId, tc: TypeContents)
4294 if Some(did) == cx.lang_items.unsafe_cell_type() {
4295 tc | TC::InteriorUnsafe
4302 fn impls_bound<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4303 bound: ty::BuiltinBound,
4307 let tcx = param_env.tcx;
4308 let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, Some(param_env.clone()), false);
4310 let is_impld = traits::type_known_to_meet_builtin_bound(&infcx,
4313 debug!("Ty::impls_bound({:?}, {:?}) = {:?}",
4314 self, bound, is_impld);
4319 // FIXME (@jroesch): I made this public to use it, not sure if should be private
4320 pub fn moves_by_default<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4321 span: Span) -> bool {
4322 if self.flags.get().intersects(TypeFlags::MOVENESS_CACHED) {
4323 return self.flags.get().intersects(TypeFlags::MOVES_BY_DEFAULT);
4326 assert!(!self.needs_infer());
4328 // Fast-path for primitive types
4329 let result = match self.sty {
4330 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
4331 TyRawPtr(..) | TyBareFn(..) | TyRef(_, TypeAndMut {
4332 mutbl: ast::MutImmutable, ..
4335 TyStr | TyBox(..) | TyRef(_, TypeAndMut {
4336 mutbl: ast::MutMutable, ..
4339 TyArray(..) | TySlice(_) | TyTrait(..) | TyTuple(..) |
4340 TyClosure(..) | TyEnum(..) | TyStruct(..) |
4341 TyProjection(..) | TyParam(..) | TyInfer(..) | TyError => None
4342 }.unwrap_or_else(|| !self.impls_bound(param_env, ty::BoundCopy, span));
4344 if !self.has_param_types() && !self.has_self_ty() {
4345 self.flags.set(self.flags.get() | if result {
4346 TypeFlags::MOVENESS_CACHED | TypeFlags::MOVES_BY_DEFAULT
4348 TypeFlags::MOVENESS_CACHED
4356 pub fn is_sized<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4359 if self.flags.get().intersects(TypeFlags::SIZEDNESS_CACHED) {
4360 return self.flags.get().intersects(TypeFlags::IS_SIZED);
4363 self.is_sized_uncached(param_env, span)
4366 fn is_sized_uncached<'a>(&'tcx self, param_env: &ParameterEnvironment<'a,'tcx>,
4367 span: Span) -> bool {
4368 assert!(!self.needs_infer());
4370 // Fast-path for primitive types
4371 let result = match self.sty {
4372 TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
4373 TyBox(..) | TyRawPtr(..) | TyRef(..) | TyBareFn(..) |
4374 TyArray(..) | TyTuple(..) | TyClosure(..) => Some(true),
4376 TyStr | TyTrait(..) | TySlice(_) => Some(false),
4378 TyEnum(..) | TyStruct(..) | TyProjection(..) | TyParam(..) |
4379 TyInfer(..) | TyError => None
4380 }.unwrap_or_else(|| self.impls_bound(param_env, ty::BoundSized, span));
4382 if !self.has_param_types() && !self.has_self_ty() {
4383 self.flags.set(self.flags.get() | if result {
4384 TypeFlags::SIZEDNESS_CACHED | TypeFlags::IS_SIZED
4386 TypeFlags::SIZEDNESS_CACHED
4393 // True if instantiating an instance of `r_ty` requires an instance of `r_ty`.
4394 pub fn is_instantiable(&'tcx self, cx: &ctxt<'tcx>) -> bool {
4395 fn type_requires<'tcx>(cx: &ctxt<'tcx>, seen: &mut Vec<DefId>,
4396 r_ty: Ty<'tcx>, ty: Ty<'tcx>) -> bool {
4397 debug!("type_requires({:?}, {:?})?",
4400 let r = r_ty == ty || subtypes_require(cx, seen, r_ty, ty);
4402 debug!("type_requires({:?}, {:?})? {:?}",
4407 fn subtypes_require<'tcx>(cx: &ctxt<'tcx>, seen: &mut Vec<DefId>,
4408 r_ty: Ty<'tcx>, ty: Ty<'tcx>) -> bool {
4409 debug!("subtypes_require({:?}, {:?})?",
4412 let r = match ty.sty {
4413 // fixed length vectors need special treatment compared to
4414 // normal vectors, since they don't necessarily have the
4415 // possibility to have length zero.
4416 TyArray(_, 0) => false, // don't need no contents
4417 TyArray(ty, _) => type_requires(cx, seen, r_ty, ty),
4432 type_requires(cx, seen, r_ty, typ)
4434 TyRef(_, ref mt) => {
4435 type_requires(cx, seen, r_ty, mt.ty)
4439 false // unsafe ptrs can always be NULL
4446 TyStruct(ref did, _) if seen.contains(did) => {
4450 TyStruct(did, substs) => {
4452 let fields = cx.struct_fields(did, substs);
4453 let r = fields.iter().any(|f| type_requires(cx, seen, r_ty, f.mt.ty));
4454 seen.pop().unwrap();
4461 // this check is run on type definitions, so we don't expect to see
4462 // inference by-products or closure types
4463 cx.sess.bug(&format!("requires check invoked on inapplicable type: {:?}", ty))
4466 TyTuple(ref ts) => {
4467 ts.iter().any(|ty| type_requires(cx, seen, r_ty, *ty))
4470 TyEnum(ref did, _) if seen.contains(did) => {
4474 TyEnum(did, substs) => {
4476 let vs = cx.enum_variants(did);
4477 let r = !vs.is_empty() && vs.iter().all(|variant| {
4478 variant.args.iter().any(|aty| {
4479 let sty = aty.subst(cx, substs);
4480 type_requires(cx, seen, r_ty, sty)
4483 seen.pop().unwrap();
4488 debug!("subtypes_require({:?}, {:?})? {:?}",
4494 let mut seen = Vec::new();
4495 !subtypes_require(cx, &mut seen, self, self)
4499 /// Describes whether a type is representable. For types that are not
4500 /// representable, 'SelfRecursive' and 'ContainsRecursive' are used to
4501 /// distinguish between types that are recursive with themselves and types that
4502 /// contain a different recursive type. These cases can therefore be treated
4503 /// differently when reporting errors.
4505 /// The ordering of the cases is significant. They are sorted so that cmp::max
4506 /// will keep the "more erroneous" of two values.
4507 #[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
4508 pub enum Representability {
4514 impl<'tcx> TyS<'tcx> {
4515 /// Check whether a type is representable. This means it cannot contain unboxed
4516 /// structural recursion. This check is needed for structs and enums.
4517 pub fn is_representable(&'tcx self, cx: &ctxt<'tcx>, sp: Span) -> Representability {
4519 // Iterate until something non-representable is found
4520 fn find_nonrepresentable<'tcx, It: Iterator<Item=Ty<'tcx>>>(cx: &ctxt<'tcx>, sp: Span,
4521 seen: &mut Vec<Ty<'tcx>>,
4523 -> Representability {
4524 iter.fold(Representable,
4525 |r, ty| cmp::max(r, is_type_structurally_recursive(cx, sp, seen, ty)))
4528 fn are_inner_types_recursive<'tcx>(cx: &ctxt<'tcx>, sp: Span,
4529 seen: &mut Vec<Ty<'tcx>>, ty: Ty<'tcx>)
4530 -> Representability {
4532 TyTuple(ref ts) => {
4533 find_nonrepresentable(cx, sp, seen, ts.iter().cloned())
4535 // Fixed-length vectors.
4536 // FIXME(#11924) Behavior undecided for zero-length vectors.
4538 is_type_structurally_recursive(cx, sp, seen, ty)
4540 TyStruct(did, substs) => {
4541 let fields = cx.struct_fields(did, substs);
4542 find_nonrepresentable(cx, sp, seen, fields.iter().map(|f| f.mt.ty))
4544 TyEnum(did, substs) => {
4545 let vs = cx.enum_variants(did);
4546 let iter = vs.iter()
4547 .flat_map(|variant| &variant.args)
4548 .map(|aty| { aty.subst_spanned(cx, substs, Some(sp)) });
4550 find_nonrepresentable(cx, sp, seen, iter)
4553 // this check is run on type definitions, so we don't expect
4554 // to see closure types
4555 cx.sess.bug(&format!("requires check invoked on inapplicable type: {:?}", ty))
4561 fn same_struct_or_enum_def_id(ty: Ty, did: DefId) -> bool {
4563 TyStruct(ty_did, _) | TyEnum(ty_did, _) => {
4570 fn same_type<'tcx>(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
4571 match (&a.sty, &b.sty) {
4572 (&TyStruct(did_a, ref substs_a), &TyStruct(did_b, ref substs_b)) |
4573 (&TyEnum(did_a, ref substs_a), &TyEnum(did_b, ref substs_b)) => {
4578 let types_a = substs_a.types.get_slice(subst::TypeSpace);
4579 let types_b = substs_b.types.get_slice(subst::TypeSpace);
4581 let mut pairs = types_a.iter().zip(types_b);
4583 pairs.all(|(&a, &b)| same_type(a, b))
4591 // Does the type `ty` directly (without indirection through a pointer)
4592 // contain any types on stack `seen`?
4593 fn is_type_structurally_recursive<'tcx>(cx: &ctxt<'tcx>, sp: Span,
4594 seen: &mut Vec<Ty<'tcx>>,
4595 ty: Ty<'tcx>) -> Representability {
4596 debug!("is_type_structurally_recursive: {:?}", ty);
4599 TyStruct(did, _) | TyEnum(did, _) => {
4601 // Iterate through stack of previously seen types.
4602 let mut iter = seen.iter();
4604 // The first item in `seen` is the type we are actually curious about.
4605 // We want to return SelfRecursive if this type contains itself.
4606 // It is important that we DON'T take generic parameters into account
4607 // for this check, so that Bar<T> in this example counts as SelfRecursive:
4610 // struct Bar<T> { x: Bar<Foo> }
4613 Some(&seen_type) => {
4614 if same_struct_or_enum_def_id(seen_type, did) {
4615 debug!("SelfRecursive: {:?} contains {:?}",
4618 return SelfRecursive;
4624 // We also need to know whether the first item contains other types
4625 // that are structurally recursive. If we don't catch this case, we
4626 // will recurse infinitely for some inputs.
4628 // It is important that we DO take generic parameters into account
4629 // here, so that code like this is considered SelfRecursive, not
4630 // ContainsRecursive:
4632 // struct Foo { Option<Option<Foo>> }
4634 for &seen_type in iter {
4635 if same_type(ty, seen_type) {
4636 debug!("ContainsRecursive: {:?} contains {:?}",
4639 return ContainsRecursive;
4644 // For structs and enums, track all previously seen types by pushing them
4645 // onto the 'seen' stack.
4647 let out = are_inner_types_recursive(cx, sp, seen, ty);
4652 // No need to push in other cases.
4653 are_inner_types_recursive(cx, sp, seen, ty)
4658 debug!("is_type_representable: {:?}", self);
4660 // To avoid a stack overflow when checking an enum variant or struct that
4661 // contains a different, structurally recursive type, maintain a stack
4662 // of seen types and check recursion for each of them (issues #3008, #3779).
4663 let mut seen: Vec<Ty> = Vec::new();
4664 let r = is_type_structurally_recursive(cx, sp, &mut seen, self);
4665 debug!("is_type_representable: {:?} is {:?}", self, r);
4669 pub fn is_trait(&self) -> bool {
4671 TyTrait(..) => true,
4676 pub fn is_integral(&self) -> bool {
4678 TyInfer(IntVar(_)) | TyInt(_) | TyUint(_) => true,
4683 pub fn is_fresh(&self) -> bool {
4685 TyInfer(FreshTy(_)) => true,
4686 TyInfer(FreshIntTy(_)) => true,
4687 TyInfer(FreshFloatTy(_)) => true,
4692 pub fn is_uint(&self) -> bool {
4694 TyInfer(IntVar(_)) | TyUint(ast::TyUs) => true,
4699 pub fn is_char(&self) -> bool {
4706 pub fn is_bare_fn(&self) -> bool {
4708 TyBareFn(..) => true,
4713 pub fn is_bare_fn_item(&self) -> bool {
4715 TyBareFn(Some(_), _) => true,
4720 pub fn is_fp(&self) -> bool {
4722 TyInfer(FloatVar(_)) | TyFloat(_) => true,
4727 pub fn is_numeric(&self) -> bool {
4728 self.is_integral() || self.is_fp()
4731 pub fn is_signed(&self) -> bool {
4738 pub fn is_machine(&self) -> bool {
4740 TyInt(ast::TyIs) | TyUint(ast::TyUs) => false,
4741 TyInt(..) | TyUint(..) | TyFloat(..) => true,
4746 // Whether a type is enum like, that is an enum type with only nullary
4748 pub fn is_c_like_enum(&self, cx: &ctxt) -> bool {
4751 let variants = cx.enum_variants(did);
4752 if variants.is_empty() {
4755 variants.iter().all(|v| v.args.is_empty())
4762 // Returns the type and mutability of *ty.
4764 // The parameter `explicit` indicates if this is an *explicit* dereference.
4765 // Some types---notably unsafe ptrs---can only be dereferenced explicitly.
4766 pub fn builtin_deref(&self, explicit: bool) -> Option<TypeAndMut<'tcx>> {
4771 mutbl: ast::MutImmutable,
4774 TyRef(_, mt) => Some(mt),
4775 TyRawPtr(mt) if explicit => Some(mt),
4780 // Returns the type of ty[i]
4781 pub fn builtin_index(&self) -> Option<Ty<'tcx>> {
4783 TyArray(ty, _) | TySlice(ty) => Some(ty),
4788 pub fn fn_sig(&self) -> &'tcx PolyFnSig<'tcx> {
4790 TyBareFn(_, ref f) => &f.sig,
4791 _ => panic!("Ty::fn_sig() called on non-fn type: {:?}", self)
4795 /// Returns the ABI of the given function.
4796 pub fn fn_abi(&self) -> abi::Abi {
4798 TyBareFn(_, ref f) => f.abi,
4799 _ => panic!("Ty::fn_abi() called on non-fn type"),
4803 // Type accessors for substructures of types
4804 pub fn fn_args(&self) -> ty::Binder<Vec<Ty<'tcx>>> {
4805 self.fn_sig().inputs()
4808 pub fn fn_ret(&self) -> Binder<FnOutput<'tcx>> {
4809 self.fn_sig().output()
4812 pub fn is_fn(&self) -> bool {
4814 TyBareFn(..) => true,
4819 /// See `expr_ty_adjusted`
4820 pub fn adjust<F>(&'tcx self, cx: &ctxt<'tcx>,
4822 expr_id: ast::NodeId,
4823 adjustment: Option<&AutoAdjustment<'tcx>>,
4826 F: FnMut(MethodCall) -> Option<Ty<'tcx>>,
4828 if let TyError = self.sty {
4832 return match adjustment {
4833 Some(adjustment) => {
4835 AdjustReifyFnPointer => {
4837 ty::TyBareFn(Some(_), b) => {
4842 &format!("AdjustReifyFnPointer adjustment on non-fn-item: \
4848 AdjustUnsafeFnPointer => {
4850 ty::TyBareFn(None, b) => cx.safe_to_unsafe_fn_ty(b),
4853 &format!("AdjustReifyFnPointer adjustment on non-fn-item: \
4860 AdjustDerefRef(ref adj) => {
4861 let mut adjusted_ty = self;
4863 if !adjusted_ty.references_error() {
4864 for i in 0..adj.autoderefs {
4865 let method_call = MethodCall::autoderef(expr_id, i as u32);
4866 match method_type(method_call) {
4867 Some(method_ty) => {
4868 // Overloaded deref operators have all late-bound
4869 // regions fully instantiated and coverge.
4871 cx.no_late_bound_regions(&method_ty.fn_ret()).unwrap();
4872 adjusted_ty = fn_ret.unwrap();
4876 match adjusted_ty.builtin_deref(true) {
4877 Some(mt) => { adjusted_ty = mt.ty; }
4881 &format!("the {}th autoderef failed: {}",
4890 if let Some(target) = adj.unsize {
4893 adjusted_ty.adjust_for_autoref(cx, adj.autoref)
4902 pub fn adjust_for_autoref(&'tcx self, cx: &ctxt<'tcx>,
4903 autoref: Option<AutoRef<'tcx>>)
4907 Some(AutoPtr(r, m)) => {
4908 cx.mk_ref(r, TypeAndMut { ty: self, mutbl: m })
4910 Some(AutoUnsafe(m)) => {
4911 cx.mk_ptr(TypeAndMut { ty: self, mutbl: m })
4916 fn sort_string(&self, cx: &ctxt) -> String {
4919 TyBool | TyChar | TyInt(_) |
4920 TyUint(_) | TyFloat(_) | TyStr => self.to_string(),
4921 TyTuple(ref tys) if tys.is_empty() => self.to_string(),
4923 TyEnum(id, _) => format!("enum `{}`", cx.item_path_str(id)),
4924 TyBox(_) => "box".to_string(),
4925 TyArray(_, n) => format!("array of {} elements", n),
4926 TySlice(_) => "slice".to_string(),
4927 TyRawPtr(_) => "*-ptr".to_string(),
4928 TyRef(_, _) => "&-ptr".to_string(),
4929 TyBareFn(Some(_), _) => format!("fn item"),
4930 TyBareFn(None, _) => "fn pointer".to_string(),
4931 TyTrait(ref inner) => {
4932 format!("trait {}", cx.item_path_str(inner.principal_def_id()))
4934 TyStruct(id, _) => {
4935 format!("struct `{}`", cx.item_path_str(id))
4937 TyClosure(..) => "closure".to_string(),
4938 TyTuple(_) => "tuple".to_string(),
4939 TyInfer(TyVar(_)) => "inferred type".to_string(),
4940 TyInfer(IntVar(_)) => "integral variable".to_string(),
4941 TyInfer(FloatVar(_)) => "floating-point variable".to_string(),
4942 TyInfer(FreshTy(_)) => "skolemized type".to_string(),
4943 TyInfer(FreshIntTy(_)) => "skolemized integral type".to_string(),
4944 TyInfer(FreshFloatTy(_)) => "skolemized floating-point type".to_string(),
4945 TyProjection(_) => "associated type".to_string(),
4947 if p.space == subst::SelfSpace {
4950 "type parameter".to_string()
4953 TyError => "type error".to_string(),
4957 /// Explains the source of a type err in a short, human readable way. This is meant to be placed
4958 /// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()`
4959 /// afterwards to present additional details, particularly when it comes to lifetime-related
4961 impl<'tcx> fmt::Display for TypeError<'tcx> {
4962 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
4963 use self::TypeError::*;
4966 CyclicTy => write!(f, "cyclic type of infinite size"),
4967 Mismatch => write!(f, "types differ"),
4968 UnsafetyMismatch(values) => {
4969 write!(f, "expected {} fn, found {} fn",
4973 AbiMismatch(values) => {
4974 write!(f, "expected {} fn, found {} fn",
4978 Mutability => write!(f, "values differ in mutability"),
4980 write!(f, "boxed values differ in mutability")
4982 VecMutability => write!(f, "vectors differ in mutability"),
4983 PtrMutability => write!(f, "pointers differ in mutability"),
4984 RefMutability => write!(f, "references differ in mutability"),
4985 TyParamSize(values) => {
4986 write!(f, "expected a type with {} type params, \
4987 found one with {} type params",
4991 FixedArraySize(values) => {
4992 write!(f, "expected an array with a fixed size of {} elements, \
4993 found one with {} elements",
4997 TupleSize(values) => {
4998 write!(f, "expected a tuple with {} elements, \
4999 found one with {} elements",
5004 write!(f, "incorrect number of function parameters")
5006 RegionsDoesNotOutlive(..) => {
5007 write!(f, "lifetime mismatch")
5009 RegionsNotSame(..) => {
5010 write!(f, "lifetimes are not the same")
5012 RegionsNoOverlap(..) => {
5013 write!(f, "lifetimes do not intersect")
5015 RegionsInsufficientlyPolymorphic(br, _) => {
5016 write!(f, "expected bound lifetime parameter {}, \
5017 found concrete lifetime", br)
5019 RegionsOverlyPolymorphic(br, _) => {
5020 write!(f, "expected concrete lifetime, \
5021 found bound lifetime parameter {}", br)
5023 Sorts(values) => tls::with(|tcx| {
5024 // A naive approach to making sure that we're not reporting silly errors such as:
5025 // (expected closure, found closure).
5026 let expected_str = values.expected.sort_string(tcx);
5027 let found_str = values.found.sort_string(tcx);
5028 if expected_str == found_str {
5029 write!(f, "expected {}, found a different {}", expected_str, found_str)
5031 write!(f, "expected {}, found {}", expected_str, found_str)
5034 Traits(values) => tls::with(|tcx| {
5035 write!(f, "expected trait `{}`, found trait `{}`",
5036 tcx.item_path_str(values.expected),
5037 tcx.item_path_str(values.found))
5039 BuiltinBoundsMismatch(values) => {
5040 if values.expected.is_empty() {
5041 write!(f, "expected no bounds, found `{}`",
5043 } else if values.found.is_empty() {
5044 write!(f, "expected bounds `{}`, found no bounds",
5047 write!(f, "expected bounds `{}`, found bounds `{}`",
5053 write!(f, "expected an integral type, found `char`")
5055 IntMismatch(ref values) => {
5056 write!(f, "expected `{:?}`, found `{:?}`",
5060 FloatMismatch(ref values) => {
5061 write!(f, "expected `{:?}`, found `{:?}`",
5065 VariadicMismatch(ref values) => {
5066 write!(f, "expected {} fn, found {} function",
5067 if values.expected { "variadic" } else { "non-variadic" },
5068 if values.found { "variadic" } else { "non-variadic" })
5070 ConvergenceMismatch(ref values) => {
5071 write!(f, "expected {} fn, found {} function",
5072 if values.expected { "converging" } else { "diverging" },
5073 if values.found { "converging" } else { "diverging" })
5075 ProjectionNameMismatched(ref values) => {
5076 write!(f, "expected {}, found {}",
5080 ProjectionBoundsLength(ref values) => {
5081 write!(f, "expected {} associated type bindings, found {}",
5085 terr_ty_param_default_mismatch(ref values) => {
5086 write!(f, "conflicting type parameter defaults {} {}",
5094 /// Helper for looking things up in the various maps that are populated during
5095 /// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc). All of
5096 /// these share the pattern that if the id is local, it should have been loaded
5097 /// into the map by the `typeck::collect` phase. If the def-id is external,
5098 /// then we have to go consult the crate loading code (and cache the result for
5100 fn lookup_locally_or_in_crate_store<V, F>(descr: &str,
5102 map: &RefCell<DefIdMap<V>>,
5103 load_external: F) -> V where
5107 match map.borrow().get(&def_id).cloned() {
5108 Some(v) => { return v; }
5112 if def_id.krate == ast::LOCAL_CRATE {
5113 panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
5115 let v = load_external();
5116 map.borrow_mut().insert(def_id, v.clone());
5121 pub fn from_mutbl(m: ast::Mutability) -> BorrowKind {
5123 ast::MutMutable => MutBorrow,
5124 ast::MutImmutable => ImmBorrow,
5128 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
5129 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
5130 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
5132 pub fn to_mutbl_lossy(self) -> ast::Mutability {
5134 MutBorrow => ast::MutMutable,
5135 ImmBorrow => ast::MutImmutable,
5137 // We have no type corresponding to a unique imm borrow, so
5138 // use `&mut`. It gives all the capabilities of an `&uniq`
5139 // and hence is a safe "over approximation".
5140 UniqueImmBorrow => ast::MutMutable,
5144 pub fn to_user_str(&self) -> &'static str {
5146 MutBorrow => "mutable",
5147 ImmBorrow => "immutable",
5148 UniqueImmBorrow => "uniquely immutable",
5153 impl<'tcx> ctxt<'tcx> {
5154 /// Returns the type of element at index `i` in tuple or tuple-like type `t`.
5155 /// For an enum `t`, `variant` is None only if `t` is a univariant enum.
5156 pub fn positional_element_ty(&self,
5159 variant: Option<ast::DefId>) -> Option<Ty<'tcx>> {
5161 match (&ty.sty, variant) {
5162 (&TyTuple(ref v), None) => v.get(i).cloned(),
5165 (&TyStruct(def_id, substs), None) => self.lookup_struct_fields(def_id)
5167 .map(|&t| self.lookup_item_type(t.id).ty.subst(self, substs)),
5169 (&TyEnum(def_id, substs), Some(variant_def_id)) => {
5170 let variant_info = self.enum_variant_with_id(def_id, variant_def_id);
5171 variant_info.args.get(i).map(|t|t.subst(self, substs))
5174 (&TyEnum(def_id, substs), None) => {
5175 assert!(self.enum_is_univariant(def_id));
5176 let enum_variants = self.enum_variants(def_id);
5177 let variant_info = &enum_variants[0];
5178 variant_info.args.get(i).map(|t|t.subst(self, substs))
5185 /// Returns the type of element at field `n` in struct or struct-like type `t`.
5186 /// For an enum `t`, `variant` must be some def id.
5187 pub fn named_element_ty(&self,
5190 variant: Option<ast::DefId>) -> Option<Ty<'tcx>> {
5192 match (&ty.sty, variant) {
5193 (&TyStruct(def_id, substs), None) => {
5194 let r = self.lookup_struct_fields(def_id);
5195 r.iter().find(|f| f.name == n)
5196 .map(|&f| self.lookup_field_type(def_id, f.id, substs))
5198 (&TyEnum(def_id, substs), Some(variant_def_id)) => {
5199 let variant_info = self.enum_variant_with_id(def_id, variant_def_id);
5200 variant_info.arg_names.as_ref()
5201 .expect("must have struct enum variant if accessing a named fields")
5202 .iter().zip(&variant_info.args)
5203 .find(|&(&name, _)| name == n)
5204 .map(|(_name, arg_t)| arg_t.subst(self, substs))
5210 pub fn node_id_to_type(&self, id: ast::NodeId) -> Ty<'tcx> {
5211 match self.node_id_to_type_opt(id) {
5213 None => self.sess.bug(
5214 &format!("node_id_to_type: no type for node `{}`",
5215 self.map.node_to_string(id)))
5219 pub fn node_id_to_type_opt(&self, id: ast::NodeId) -> Option<Ty<'tcx>> {
5220 self.tables.borrow().node_types.get(&id).cloned()
5223 pub fn node_id_item_substs(&self, id: ast::NodeId) -> ItemSubsts<'tcx> {
5224 match self.tables.borrow().item_substs.get(&id) {
5225 None => ItemSubsts::empty(),
5226 Some(ts) => ts.clone(),
5230 // Returns the type of a pattern as a monotype. Like @expr_ty, this function
5231 // doesn't provide type parameter substitutions.
5232 pub fn pat_ty(&self, pat: &ast::Pat) -> Ty<'tcx> {
5233 self.node_id_to_type(pat.id)
5235 pub fn pat_ty_opt(&self, pat: &ast::Pat) -> Option<Ty<'tcx>> {
5236 self.node_id_to_type_opt(pat.id)
5239 // Returns the type of an expression as a monotype.
5241 // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression. That is, in
5242 // some cases, we insert `AutoAdjustment` annotations such as auto-deref or
5243 // auto-ref. The type returned by this function does not consider such
5244 // adjustments. See `expr_ty_adjusted()` instead.
5246 // NB (2): This type doesn't provide type parameter substitutions; e.g. if you
5247 // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
5248 // instead of "fn(ty) -> T with T = isize".
5249 pub fn expr_ty(&self, expr: &ast::Expr) -> Ty<'tcx> {
5250 self.node_id_to_type(expr.id)
5253 pub fn expr_ty_opt(&self, expr: &ast::Expr) -> Option<Ty<'tcx>> {
5254 self.node_id_to_type_opt(expr.id)
5257 /// Returns the type of `expr`, considering any `AutoAdjustment`
5258 /// entry recorded for that expression.
5260 /// It would almost certainly be better to store the adjusted ty in with
5261 /// the `AutoAdjustment`, but I opted not to do this because it would
5262 /// require serializing and deserializing the type and, although that's not
5263 /// hard to do, I just hate that code so much I didn't want to touch it
5264 /// unless it was to fix it properly, which seemed a distraction from the
5265 /// thread at hand! -nmatsakis
5266 pub fn expr_ty_adjusted(&self, expr: &ast::Expr) -> Ty<'tcx> {
5268 .adjust(self, expr.span, expr.id,
5269 self.tables.borrow().adjustments.get(&expr.id),
5271 self.tables.borrow().method_map.get(&method_call).map(|method| method.ty)
5275 pub fn expr_span(&self, id: NodeId) -> Span {
5276 match self.map.find(id) {
5277 Some(ast_map::NodeExpr(e)) => {
5281 self.sess.bug(&format!("Node id {} is not an expr: {:?}",
5285 self.sess.bug(&format!("Node id {} is not present \
5286 in the node map", id));
5291 pub fn local_var_name_str(&self, id: NodeId) -> InternedString {
5292 match self.map.find(id) {
5293 Some(ast_map::NodeLocal(pat)) => {
5295 ast::PatIdent(_, ref path1, _) => {
5296 token::get_ident(path1.node)
5299 self.sess.bug(&format!("Variable id {} maps to {:?}, not local",
5305 self.sess.bug(&format!("Variable id {} maps to {:?}, not local",
5311 pub fn resolve_expr(&self, expr: &ast::Expr) -> def::Def {
5312 match self.def_map.borrow().get(&expr.id) {
5313 Some(def) => def.full_def(),
5315 self.sess.span_bug(expr.span, &format!(
5316 "no def-map entry for expr {}", expr.id));
5321 pub fn expr_is_lval(&self, expr: &ast::Expr) -> bool {
5323 ast::ExprPath(..) => {
5324 // We can't use resolve_expr here, as this needs to run on broken
5325 // programs. We don't need to through - associated items are all
5327 match self.def_map.borrow().get(&expr.id) {
5328 Some(&def::PathResolution {
5329 base_def: def::DefStatic(..), ..
5330 }) | Some(&def::PathResolution {
5331 base_def: def::DefUpvar(..), ..
5332 }) | Some(&def::PathResolution {
5333 base_def: def::DefLocal(..), ..
5340 None => self.sess.span_bug(expr.span, &format!(
5341 "no def for path {}", expr.id))
5345 ast::ExprUnary(ast::UnDeref, _) |
5346 ast::ExprField(..) |
5347 ast::ExprTupField(..) |
5348 ast::ExprIndex(..) => {
5353 ast::ExprMethodCall(..) |
5354 ast::ExprStruct(..) |
5355 ast::ExprRange(..) |
5358 ast::ExprMatch(..) |
5359 ast::ExprClosure(..) |
5360 ast::ExprBlock(..) |
5361 ast::ExprRepeat(..) |
5363 ast::ExprBreak(..) |
5364 ast::ExprAgain(..) |
5366 ast::ExprWhile(..) |
5368 ast::ExprAssign(..) |
5369 ast::ExprInlineAsm(..) |
5370 ast::ExprAssignOp(..) |
5372 ast::ExprUnary(..) |
5374 ast::ExprAddrOf(..) |
5375 ast::ExprBinary(..) |
5376 ast::ExprCast(..) => {
5380 ast::ExprParen(ref e) => self.expr_is_lval(e),
5382 ast::ExprIfLet(..) |
5383 ast::ExprWhileLet(..) |
5384 ast::ExprForLoop(..) |
5385 ast::ExprMac(..) => {
5388 "macro expression remains after expansion");
5393 pub fn field_idx_strict(&self, name: ast::Name, fields: &[Field<'tcx>])
5396 for f in fields { if f.name == name { return i; } i += 1; }
5397 self.sess.bug(&format!(
5398 "no field named `{}` found in the list of fields `{:?}`",
5399 token::get_name(name),
5401 .map(|f| token::get_name(f.name).to_string())
5402 .collect::<Vec<String>>()));
5405 pub fn note_and_explain_type_err(&self, err: &TypeError<'tcx>, sp: Span) {
5406 use self::TypeError::*;
5409 RegionsDoesNotOutlive(subregion, superregion) => {
5410 self.note_and_explain_region("", subregion, "...");
5411 self.note_and_explain_region("...does not necessarily outlive ",
5414 RegionsNotSame(region1, region2) => {
5415 self.note_and_explain_region("", region1, "...");
5416 self.note_and_explain_region("...is not the same lifetime as ",
5419 RegionsNoOverlap(region1, region2) => {
5420 self.note_and_explain_region("", region1, "...");
5421 self.note_and_explain_region("...does not overlap ",
5424 RegionsInsufficientlyPolymorphic(_, conc_region) => {
5425 self.note_and_explain_region("concrete lifetime that was found is ",
5428 RegionsOverlyPolymorphic(_, ty::ReInfer(ty::ReVar(_))) => {
5429 // don't bother to print out the message below for
5430 // inference variables, it's not very illuminating.
5432 RegionsOverlyPolymorphic(_, conc_region) => {
5433 self.note_and_explain_region("expected concrete lifetime is ",
5437 let expected_str = values.expected.sort_string(self);
5438 let found_str = values.found.sort_string(self);
5439 if expected_str == found_str && expected_str == "closure" {
5440 self.sess.span_note(sp,
5441 &format!("no two closures, even if identical, have the same type"));
5442 self.sess.span_help(sp,
5443 &format!("consider boxing your closure and/or \
5444 using it as a trait object"));
5447 terr_ty_param_default_mismatch(expected) => {
5448 self.sess.span_note(sp,
5449 &format!("found conflicting defaults {:?} {:?}",
5450 expected.expected, expected.found))
5456 pub fn provided_source(&self, id: ast::DefId) -> Option<ast::DefId> {
5457 self.provided_method_sources.borrow().get(&id).cloned()
5460 pub fn provided_trait_methods(&self, id: ast::DefId) -> Vec<Rc<Method<'tcx>>> {
5462 if let ItemTrait(_, _, _, ref ms) = self.map.expect_item(id.node).node {
5463 ms.iter().filter_map(|ti| {
5464 if let ast::MethodTraitItem(_, Some(_)) = ti.node {
5465 match self.impl_or_trait_item(ast_util::local_def(ti.id)) {
5466 MethodTraitItem(m) => Some(m),
5468 self.sess.bug("provided_trait_methods(): \
5469 non-method item found from \
5470 looking up provided method?!")
5478 self.sess.bug(&format!("provided_trait_methods: `{:?}` is not a trait", id))
5481 csearch::get_provided_trait_methods(self, id)
5485 pub fn associated_consts(&self, id: ast::DefId) -> Vec<Rc<AssociatedConst<'tcx>>> {
5487 match self.map.expect_item(id.node).node {
5488 ItemTrait(_, _, _, ref tis) => {
5489 tis.iter().filter_map(|ti| {
5490 if let ast::ConstTraitItem(_, _) = ti.node {
5491 match self.impl_or_trait_item(ast_util::local_def(ti.id)) {
5492 ConstTraitItem(ac) => Some(ac),
5494 self.sess.bug("associated_consts(): \
5495 non-const item found from \
5496 looking up a constant?!")
5504 ItemImpl(_, _, _, _, _, ref iis) => {
5505 iis.iter().filter_map(|ii| {
5506 if let ast::ConstImplItem(_, _) = ii.node {
5507 match self.impl_or_trait_item(ast_util::local_def(ii.id)) {
5508 ConstTraitItem(ac) => Some(ac),
5510 self.sess.bug("associated_consts(): \
5511 non-const item found from \
5512 looking up a constant?!")
5521 self.sess.bug(&format!("associated_consts: `{:?}` is not a trait \
5526 csearch::get_associated_consts(self, id)
5530 pub fn trait_items(&self, trait_did: ast::DefId) -> Rc<Vec<ImplOrTraitItem<'tcx>>> {
5531 let mut trait_items = self.trait_items_cache.borrow_mut();
5532 match trait_items.get(&trait_did).cloned() {
5533 Some(trait_items) => trait_items,
5535 let def_ids = self.trait_item_def_ids(trait_did);
5536 let items: Rc<Vec<ImplOrTraitItem>> =
5537 Rc::new(def_ids.iter()
5538 .map(|d| self.impl_or_trait_item(d.def_id()))
5540 trait_items.insert(trait_did, items.clone());
5546 pub fn trait_impl_polarity(&self, id: ast::DefId) -> Option<ast::ImplPolarity> {
5547 if id.krate == ast::LOCAL_CRATE {
5548 match self.map.find(id.node) {
5549 Some(ast_map::NodeItem(item)) => {
5551 ast::ItemImpl(_, polarity, _, _, _, _) => Some(polarity),
5558 csearch::get_impl_polarity(self, id)
5562 pub fn custom_coerce_unsized_kind(&self, did: ast::DefId) -> CustomCoerceUnsized {
5563 memoized(&self.custom_coerce_unsized_kinds, did, |did: DefId| {
5564 let (kind, src) = if did.krate != ast::LOCAL_CRATE {
5565 (csearch::get_custom_coerce_unsized_kind(self, did), "external")
5573 self.sess.bug(&format!("custom_coerce_unsized_kind: \
5574 {} impl `{}` is missing its kind",
5575 src, self.item_path_str(did)));
5581 pub fn impl_or_trait_item(&self, id: ast::DefId) -> ImplOrTraitItem<'tcx> {
5582 lookup_locally_or_in_crate_store(
5583 "impl_or_trait_items", id, &self.impl_or_trait_items,
5584 || csearch::get_impl_or_trait_item(self, id))
5587 pub fn trait_item_def_ids(&self, id: ast::DefId) -> Rc<Vec<ImplOrTraitItemId>> {
5588 lookup_locally_or_in_crate_store(
5589 "trait_item_def_ids", id, &self.trait_item_def_ids,
5590 || Rc::new(csearch::get_trait_item_def_ids(&self.sess.cstore, id)))
5593 /// Returns the trait-ref corresponding to a given impl, or None if it is
5594 /// an inherent impl.
5595 pub fn impl_trait_ref(&self, id: ast::DefId) -> Option<TraitRef<'tcx>> {
5596 lookup_locally_or_in_crate_store(
5597 "impl_trait_refs", id, &self.impl_trait_refs,
5598 || csearch::get_impl_trait(self, id))
5601 /// Returns whether this DefId refers to an impl
5602 pub fn is_impl(&self, id: ast::DefId) -> bool {
5603 if id.krate == ast::LOCAL_CRATE {
5604 if let Some(ast_map::NodeItem(
5605 &ast::Item { node: ast::ItemImpl(..), .. })) = self.map.find(id.node) {
5611 csearch::is_impl(&self.sess.cstore, id)
5615 pub fn trait_ref_to_def_id(&self, tr: &ast::TraitRef) -> ast::DefId {
5616 self.def_map.borrow().get(&tr.ref_id).expect("no def-map entry for trait").def_id()
5619 pub fn try_add_builtin_trait(&self,
5620 trait_def_id: ast::DefId,
5621 builtin_bounds: &mut EnumSet<BuiltinBound>)
5624 //! Checks whether `trait_ref` refers to one of the builtin
5625 //! traits, like `Send`, and adds the corresponding
5626 //! bound to the set `builtin_bounds` if so. Returns true if `trait_ref`
5627 //! is a builtin trait.
5629 match self.lang_items.to_builtin_kind(trait_def_id) {
5630 Some(bound) => { builtin_bounds.insert(bound); true }
5635 pub fn substd_enum_variants(&self,
5637 substs: &Substs<'tcx>)
5638 -> Vec<Rc<VariantInfo<'tcx>>> {
5639 self.enum_variants(id).iter().map(|variant_info| {
5640 let substd_args = variant_info.args.iter()
5641 .map(|aty| aty.subst(self, substs)).collect::<Vec<_>>();
5643 let substd_ctor_ty = variant_info.ctor_ty.subst(self, substs);
5645 Rc::new(VariantInfo {
5647 ctor_ty: substd_ctor_ty,
5648 ..(**variant_info).clone()
5653 pub fn item_path_str(&self, id: ast::DefId) -> String {
5654 self.with_path(id, |path| ast_map::path_to_string(path))
5657 /* If struct_id names a struct with a dtor. */
5658 pub fn ty_dtor(&self, struct_id: DefId) -> DtorKind {
5659 match self.destructor_for_type.borrow().get(&struct_id) {
5660 Some(&method_def_id) => {
5661 let flag = !self.has_attr(struct_id, "unsafe_no_drop_flag");
5663 TraitDtor(method_def_id, flag)
5669 pub fn has_dtor(&self, struct_id: DefId) -> bool {
5670 self.destructor_for_type.borrow().contains_key(&struct_id)
5673 pub fn with_path<T, F>(&self, id: ast::DefId, f: F) -> T where
5674 F: FnOnce(ast_map::PathElems) -> T,
5676 if id.krate == ast::LOCAL_CRATE {
5677 self.map.with_path(id.node, f)
5679 f(csearch::get_item_path(self, id).iter().cloned().chain(LinkedPath::empty()))
5683 pub fn enum_is_univariant(&self, id: ast::DefId) -> bool {
5684 self.enum_variants(id).len() == 1
5687 /// Returns `(normalized_type, ty)`, where `normalized_type` is the
5688 /// IntType representation of one of {i64,i32,i16,i8,u64,u32,u16,u8},
5689 /// and `ty` is the original type (i.e. may include `isize` or
5691 pub fn enum_repr_type(&self, opt_hint: Option<&attr::ReprAttr>)
5692 -> (attr::IntType, Ty<'tcx>) {
5693 let repr_type = match opt_hint {
5694 // Feed in the given type
5695 Some(&attr::ReprInt(_, int_t)) => int_t,
5696 // ... but provide sensible default if none provided
5698 // NB. Historically `fn enum_variants` generate i64 here, while
5699 // rustc_typeck::check would generate isize.
5700 _ => SignedInt(ast::TyIs),
5703 let repr_type_ty = repr_type.to_ty(self);
5704 let repr_type = match repr_type {
5705 SignedInt(ast::TyIs) =>
5706 SignedInt(self.sess.target.int_type),
5707 UnsignedInt(ast::TyUs) =>
5708 UnsignedInt(self.sess.target.uint_type),
5712 (repr_type, repr_type_ty)
5715 fn report_discrim_overflow(&self,
5718 repr_type: attr::IntType,
5720 let computed_value = repr_type.disr_wrap_incr(Some(prev_val));
5721 let computed_value = repr_type.disr_string(computed_value);
5722 let prev_val = repr_type.disr_string(prev_val);
5723 let repr_type = repr_type.to_ty(self);
5724 span_err!(self.sess, variant_span, E0370,
5725 "enum discriminant overflowed on value after {}: {}; \
5726 set explicitly via {} = {} if that is desired outcome",
5727 prev_val, repr_type, variant_name, computed_value);
5730 // This computes the discriminant values for the sequence of Variants
5731 // attached to a particular enum, taking into account the #[repr] (if
5732 // any) provided via the `opt_hint`.
5733 fn compute_enum_variants(&self,
5734 vs: &'tcx [P<ast::Variant>],
5735 opt_hint: Option<&attr::ReprAttr>)
5736 -> Vec<Rc<ty::VariantInfo<'tcx>>> {
5737 let mut variants: Vec<Rc<ty::VariantInfo>> = Vec::new();
5738 let mut prev_disr_val: Option<ty::Disr> = None;
5740 let (repr_type, repr_type_ty) = self.enum_repr_type(opt_hint);
5743 // If the discriminant value is specified explicitly in the
5744 // enum, check whether the initialization expression is valid,
5745 // otherwise use the last value plus one.
5746 let current_disr_val;
5748 // This closure marks cases where, when an error occurs during
5749 // the computation, attempt to assign a (hopefully) fresh
5750 // value to avoid spurious error reports downstream.
5751 let attempt_fresh_value = move || -> Disr {
5752 repr_type.disr_wrap_incr(prev_disr_val)
5755 match v.node.disr_expr {
5757 debug!("disr expr, checking {}", pprust::expr_to_string(&**e));
5759 let hint = UncheckedExprHint(repr_type_ty);
5760 match const_eval::eval_const_expr_partial(self, &**e, hint) {
5761 Ok(ConstVal::Int(val)) => current_disr_val = val as Disr,
5762 Ok(ConstVal::Uint(val)) => current_disr_val = val as Disr,
5764 let sign_desc = if repr_type.is_signed() {
5769 span_err!(self.sess, e.span, E0079,
5770 "expected {} integer constant",
5772 current_disr_val = attempt_fresh_value();
5775 span_err!(self.sess, err.span, E0080,
5776 "constant evaluation error: {}",
5778 current_disr_val = attempt_fresh_value();
5783 current_disr_val = match prev_disr_val {
5784 Some(prev_disr_val) => {
5785 if let Some(v) = repr_type.disr_incr(prev_disr_val) {
5788 self.report_discrim_overflow(v.span, v.node.name.as_str(),
5789 repr_type, prev_disr_val);
5790 attempt_fresh_value()
5793 None => ty::INITIAL_DISCRIMINANT_VALUE
5798 let variant_info = Rc::new(VariantInfo::from_ast_variant(self, &**v, current_disr_val));
5799 prev_disr_val = Some(current_disr_val);
5801 variants.push(variant_info);
5807 pub fn enum_variants(&self, id: ast::DefId) -> Rc<Vec<Rc<VariantInfo<'tcx>>>> {
5808 memoized(&self.enum_var_cache, id, |id: ast::DefId| {
5809 if ast::LOCAL_CRATE != id.krate {
5810 Rc::new(csearch::get_enum_variants(self, id))
5812 match self.map.get(id.node) {
5813 ast_map::NodeItem(ref item) => {
5815 ast::ItemEnum(ref enum_definition, _) => {
5816 Rc::new(self.compute_enum_variants(
5817 &enum_definition.variants,
5818 self.lookup_repr_hints(id).get(0)))
5821 self.sess.bug("enum_variants: id not bound to an enum")
5825 _ => self.sess.bug("enum_variants: id not bound to an enum")
5831 // Returns information about the enum variant with the given ID:
5832 pub fn enum_variant_with_id(&self,
5833 enum_id: ast::DefId,
5834 variant_id: ast::DefId)
5835 -> Rc<VariantInfo<'tcx>> {
5836 self.enum_variants(enum_id).iter()
5837 .find(|variant| variant.id == variant_id)
5838 .expect("enum_variant_with_id(): no variant exists with that ID")
5842 // Register a given item type
5843 pub fn register_item_type(&self, did: ast::DefId, ty: TypeScheme<'tcx>) {
5844 self.tcache.borrow_mut().insert(did, ty);
5847 // If the given item is in an external crate, looks up its type and adds it to
5848 // the type cache. Returns the type parameters and type.
5849 pub fn lookup_item_type(&self, did: ast::DefId) -> TypeScheme<'tcx> {
5850 lookup_locally_or_in_crate_store(
5851 "tcache", did, &self.tcache,
5852 || csearch::get_type(self, did))
5855 /// Given the did of a trait, returns its canonical trait ref.
5856 pub fn lookup_trait_def(&self, did: ast::DefId) -> &'tcx TraitDef<'tcx> {
5857 lookup_locally_or_in_crate_store(
5858 "trait_defs", did, &self.trait_defs,
5859 || self.arenas.trait_defs.alloc(csearch::get_trait_def(self, did))
5863 /// Given the did of an item, returns its full set of predicates.
5864 pub fn lookup_predicates(&self, did: ast::DefId) -> GenericPredicates<'tcx> {
5865 lookup_locally_or_in_crate_store(
5866 "predicates", did, &self.predicates,
5867 || csearch::get_predicates(self, did))
5870 /// Given the did of a trait, returns its superpredicates.
5871 pub fn lookup_super_predicates(&self, did: ast::DefId) -> GenericPredicates<'tcx> {
5872 lookup_locally_or_in_crate_store(
5873 "super_predicates", did, &self.super_predicates,
5874 || csearch::get_super_predicates(self, did))
5877 /// Get the attributes of a definition.
5878 pub fn get_attrs(&self, did: DefId) -> Cow<'tcx, [ast::Attribute]> {
5880 Cow::Borrowed(self.map.attrs(did.node))
5882 Cow::Owned(csearch::get_item_attrs(&self.sess.cstore, did))
5886 /// Determine whether an item is annotated with an attribute
5887 pub fn has_attr(&self, did: DefId, attr: &str) -> bool {
5888 self.get_attrs(did).iter().any(|item| item.check_name(attr))
5891 /// Determine whether an item is annotated with `#[repr(packed)]`
5892 pub fn lookup_packed(&self, did: DefId) -> bool {
5893 self.lookup_repr_hints(did).contains(&attr::ReprPacked)
5896 /// Determine whether an item is annotated with `#[simd]`
5897 pub fn lookup_simd(&self, did: DefId) -> bool {
5898 self.has_attr(did, "simd")
5901 /// Obtain the representation annotation for a struct definition.
5902 pub fn lookup_repr_hints(&self, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
5903 memoized(&self.repr_hint_cache, did, |did: DefId| {
5904 Rc::new(if did.krate == LOCAL_CRATE {
5905 self.get_attrs(did).iter().flat_map(|meta| {
5906 attr::find_repr_attrs(self.sess.diagnostic(), meta).into_iter()
5909 csearch::get_repr_attrs(&self.sess.cstore, did)
5914 // Look up a field ID, whether or not it's local
5915 pub fn lookup_field_type_unsubstituted(&self,
5919 if id.krate == ast::LOCAL_CRATE {
5920 self.node_id_to_type(id.node)
5922 memoized(&self.tcache, id,
5923 |id| csearch::get_field_type(self, struct_id, id)).ty
5928 // Look up a field ID, whether or not it's local
5929 // Takes a list of type substs in case the struct is generic
5930 pub fn lookup_field_type(&self,
5933 substs: &Substs<'tcx>)
5935 self.lookup_field_type_unsubstituted(struct_id, id).subst(self, substs)
5938 // Look up the list of field names and IDs for a given struct.
5939 // Panics if the id is not bound to a struct.
5940 pub fn lookup_struct_fields(&self, did: ast::DefId) -> Vec<FieldTy> {
5941 if did.krate == ast::LOCAL_CRATE {
5942 let struct_fields = self.struct_fields.borrow();
5943 match struct_fields.get(&did) {
5944 Some(fields) => (**fields).clone(),
5947 &format!("ID not mapped to struct fields: {}",
5948 self.map.node_to_string(did.node)));
5952 csearch::get_struct_fields(&self.sess.cstore, did)
5956 pub fn is_tuple_struct(&self, did: ast::DefId) -> bool {
5957 let fields = self.lookup_struct_fields(did);
5958 !fields.is_empty() && fields.iter().all(|f| f.name == token::special_names::unnamed_field)
5961 // Returns a list of fields corresponding to the struct's items. trans uses
5962 // this. Takes a list of substs with which to instantiate field types.
5963 pub fn struct_fields(&self, did: ast::DefId, substs: &Substs<'tcx>)
5964 -> Vec<Field<'tcx>> {
5965 self.lookup_struct_fields(did).iter().map(|f| {
5969 ty: self.lookup_field_type(did, f.id, substs),
5976 /// Returns the deeply last field of nested structures, or the same type,
5977 /// if not a structure at all. Corresponds to the only possible unsized
5978 /// field, and its type can be used to determine unsizing strategy.
5979 pub fn struct_tail(&self, mut ty: Ty<'tcx>) -> Ty<'tcx> {
5980 while let TyStruct(def_id, substs) = ty.sty {
5981 match self.struct_fields(def_id, substs).last() {
5982 Some(f) => ty = f.mt.ty,
5989 /// Same as applying struct_tail on `source` and `target`, but only
5990 /// keeps going as long as the two types are instances of the same
5991 /// structure definitions.
5992 /// For `(Foo<Foo<T>>, Foo<Trait>)`, the result will be `(Foo<T>, Trait)`,
5993 /// whereas struct_tail produces `T`, and `Trait`, respectively.
5994 pub fn struct_lockstep_tails(&self,
5997 -> (Ty<'tcx>, Ty<'tcx>) {
5998 let (mut a, mut b) = (source, target);
5999 while let (&TyStruct(a_did, a_substs), &TyStruct(b_did, b_substs)) = (&a.sty, &b.sty) {
6003 if let Some(a_f) = self.struct_fields(a_did, a_substs).last() {
6004 if let Some(b_f) = self.struct_fields(b_did, b_substs).last() {
6017 // Returns the repeat count for a repeating vector expression.
6018 pub fn eval_repeat_count(&self, count_expr: &ast::Expr) -> usize {
6019 let hint = UncheckedExprHint(self.types.usize);
6020 match const_eval::eval_const_expr_partial(self, count_expr, hint) {
6022 let found = match val {
6023 ConstVal::Uint(count) => return count as usize,
6024 ConstVal::Int(count) if count >= 0 => return count as usize,
6025 const_val => const_val.description(),
6027 span_err!(self.sess, count_expr.span, E0306,
6028 "expected positive integer for repeat count, found {}",
6032 let err_description = err.description();
6033 let found = match count_expr.node {
6034 ast::ExprPath(None, ast::Path {
6038 }) if segments.len() == 1 =>
6039 format!("{}", "found variable"),
6041 format!("but {}", err_description),
6043 span_err!(self.sess, count_expr.span, E0307,
6044 "expected constant integer for repeat count, {}",
6051 // Iterate over a type parameter's bounded traits and any supertraits
6052 // of those traits, ignoring kinds.
6053 // Here, the supertraits are the transitive closure of the supertrait
6054 // relation on the supertraits from each bounded trait's constraint
6056 pub fn each_bound_trait_and_supertraits<F>(&self,
6057 bounds: &[PolyTraitRef<'tcx>],
6060 F: FnMut(PolyTraitRef<'tcx>) -> bool,
6062 for bound_trait_ref in traits::transitive_bounds(self, bounds) {
6063 if !f(bound_trait_ref) {
6070 /// Given a set of predicates that apply to an object type, returns
6071 /// the region bounds that the (erased) `Self` type must
6072 /// outlive. Precisely *because* the `Self` type is erased, the
6073 /// parameter `erased_self_ty` must be supplied to indicate what type
6074 /// has been used to represent `Self` in the predicates
6075 /// themselves. This should really be a unique type; `FreshTy(0)` is a
6078 /// Requires that trait definitions have been processed so that we can
6079 /// elaborate predicates and walk supertraits.
6080 pub fn required_region_bounds(&self,
6081 erased_self_ty: Ty<'tcx>,
6082 predicates: Vec<ty::Predicate<'tcx>>)
6085 debug!("required_region_bounds(erased_self_ty={:?}, predicates={:?})",
6089 assert!(!erased_self_ty.has_escaping_regions());
6091 traits::elaborate_predicates(self, predicates)
6092 .filter_map(|predicate| {
6094 ty::Predicate::Projection(..) |
6095 ty::Predicate::Trait(..) |
6096 ty::Predicate::Equate(..) |
6097 ty::Predicate::RegionOutlives(..) => {
6100 ty::Predicate::TypeOutlives(ty::Binder(ty::OutlivesPredicate(t, r))) => {
6101 // Search for a bound of the form `erased_self_ty
6102 // : 'a`, but be wary of something like `for<'a>
6103 // erased_self_ty : 'a` (we interpret a
6104 // higher-ranked bound like that as 'static,
6105 // though at present the code in `fulfill.rs`
6106 // considers such bounds to be unsatisfiable, so
6107 // it's kind of a moot point since you could never
6108 // construct such an object, but this seems
6109 // correct even if that code changes).
6110 if t == erased_self_ty && !r.has_escaping_regions() {
6111 if r.has_escaping_regions() {
6125 pub fn item_variances(&self, item_id: ast::DefId) -> Rc<ItemVariances> {
6126 lookup_locally_or_in_crate_store(
6127 "item_variance_map", item_id, &self.item_variance_map,
6128 || Rc::new(csearch::get_item_variances(&self.sess.cstore, item_id)))
6131 pub fn trait_has_default_impl(&self, trait_def_id: DefId) -> bool {
6132 self.populate_implementations_for_trait_if_necessary(trait_def_id);
6134 let def = self.lookup_trait_def(trait_def_id);
6135 def.flags.get().intersects(TraitFlags::HAS_DEFAULT_IMPL)
6138 /// Records a trait-to-implementation mapping.
6139 pub fn record_trait_has_default_impl(&self, trait_def_id: DefId) {
6140 let def = self.lookup_trait_def(trait_def_id);
6141 def.flags.set(def.flags.get() | TraitFlags::HAS_DEFAULT_IMPL)
6144 /// Load primitive inherent implementations if necessary
6145 pub fn populate_implementations_for_primitive_if_necessary(&self,
6146 primitive_def_id: ast::DefId) {
6147 if primitive_def_id.krate == LOCAL_CRATE {
6151 if self.populated_external_primitive_impls.borrow().contains(&primitive_def_id) {
6155 debug!("populate_implementations_for_primitive_if_necessary: searching for {:?}",
6158 let impl_items = csearch::get_impl_items(&self.sess.cstore, primitive_def_id);
6160 // Store the implementation info.
6161 self.impl_items.borrow_mut().insert(primitive_def_id, impl_items);
6162 self.populated_external_primitive_impls.borrow_mut().insert(primitive_def_id);
6165 /// Populates the type context with all the inherent implementations for
6166 /// the given type if necessary.
6167 pub fn populate_inherent_implementations_for_type_if_necessary(&self,
6168 type_id: ast::DefId) {
6169 if type_id.krate == LOCAL_CRATE {
6173 if self.populated_external_types.borrow().contains(&type_id) {
6177 debug!("populate_inherent_implementations_for_type_if_necessary: searching for {:?}",
6180 let mut inherent_impls = Vec::new();
6181 csearch::each_inherent_implementation_for_type(&self.sess.cstore, type_id, |impl_def_id| {
6182 // Record the implementation.
6183 inherent_impls.push(impl_def_id);
6185 // Store the implementation info.
6186 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
6187 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
6190 self.inherent_impls.borrow_mut().insert(type_id, Rc::new(inherent_impls));
6191 self.populated_external_types.borrow_mut().insert(type_id);
6194 /// Populates the type context with all the implementations for the given
6195 /// trait if necessary.
6196 pub fn populate_implementations_for_trait_if_necessary(&self, trait_id: ast::DefId) {
6197 if trait_id.krate == LOCAL_CRATE {
6201 let def = self.lookup_trait_def(trait_id);
6202 if def.flags.get().intersects(TraitFlags::IMPLS_VALID) {
6206 debug!("populate_implementations_for_trait_if_necessary: searching for {:?}", def);
6208 if csearch::is_defaulted_trait(&self.sess.cstore, trait_id) {
6209 self.record_trait_has_default_impl(trait_id);
6212 csearch::each_implementation_for_trait(&self.sess.cstore, trait_id, |impl_def_id| {
6213 let impl_items = csearch::get_impl_items(&self.sess.cstore, impl_def_id);
6214 let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
6215 // Record the trait->implementation mapping.
6216 def.record_impl(self, impl_def_id, trait_ref);
6218 // For any methods that use a default implementation, add them to
6219 // the map. This is a bit unfortunate.
6220 for impl_item_def_id in &impl_items {
6221 let method_def_id = impl_item_def_id.def_id();
6222 match self.impl_or_trait_item(method_def_id) {
6223 MethodTraitItem(method) => {
6224 if let Some(source) = method.provided_source {
6225 self.provided_method_sources
6227 .insert(method_def_id, source);
6234 // Store the implementation info.
6235 self.impl_items.borrow_mut().insert(impl_def_id, impl_items);
6238 def.flags.set(def.flags.get() | TraitFlags::IMPLS_VALID);
6241 /// Given the def_id of an impl, return the def_id of the trait it implements.
6242 /// If it implements no trait, return `None`.
6243 pub fn trait_id_of_impl(&self, def_id: ast::DefId) -> Option<ast::DefId> {
6244 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
6247 /// If the given def ID describes a method belonging to an impl, return the
6248 /// ID of the impl that the method belongs to. Otherwise, return `None`.
6249 pub fn impl_of_method(&self, def_id: ast::DefId) -> Option<ast::DefId> {
6250 if def_id.krate != LOCAL_CRATE {
6251 return match csearch::get_impl_or_trait_item(self,
6252 def_id).container() {
6253 TraitContainer(_) => None,
6254 ImplContainer(def_id) => Some(def_id),
6257 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
6258 Some(trait_item) => {
6259 match trait_item.container() {
6260 TraitContainer(_) => None,
6261 ImplContainer(def_id) => Some(def_id),
6268 /// If the given def ID describes an item belonging to a trait (either a
6269 /// default method or an implementation of a trait method), return the ID of
6270 /// the trait that the method belongs to. Otherwise, return `None`.
6271 pub fn trait_of_item(&self, def_id: ast::DefId) -> Option<ast::DefId> {
6272 if def_id.krate != LOCAL_CRATE {
6273 return csearch::get_trait_of_item(&self.sess.cstore, def_id, self);
6275 match self.impl_or_trait_items.borrow().get(&def_id).cloned() {
6276 Some(impl_or_trait_item) => {
6277 match impl_or_trait_item.container() {
6278 TraitContainer(def_id) => Some(def_id),
6279 ImplContainer(def_id) => self.trait_id_of_impl(def_id),
6286 /// If the given def ID describes an item belonging to a trait, (either a
6287 /// default method or an implementation of a trait method), return the ID of
6288 /// the method inside trait definition (this means that if the given def ID
6289 /// is already that of the original trait method, then the return value is
6291 /// Otherwise, return `None`.
6292 pub fn trait_item_of_item(&self, def_id: ast::DefId) -> Option<ImplOrTraitItemId> {
6293 let impl_item = match self.impl_or_trait_items.borrow().get(&def_id) {
6294 Some(m) => m.clone(),
6295 None => return None,
6297 let name = impl_item.name();
6298 match self.trait_of_item(def_id) {
6299 Some(trait_did) => {
6300 self.trait_items(trait_did).iter()
6301 .find(|item| item.name() == name)
6302 .map(|item| item.id())
6308 /// Creates a hash of the type `Ty` which will be the same no matter what crate
6309 /// context it's calculated within. This is used by the `type_id` intrinsic.
6310 pub fn hash_crate_independent(&self, ty: Ty<'tcx>, svh: &Svh) -> u64 {
6311 let mut state = SipHasher::new();
6312 helper(self, ty, svh, &mut state);
6313 return state.finish();
6315 fn helper<'tcx>(tcx: &ctxt<'tcx>, ty: Ty<'tcx>, svh: &Svh,
6316 state: &mut SipHasher) {
6317 macro_rules! byte { ($b:expr) => { ($b as u8).hash(state) } }
6318 macro_rules! hash { ($e:expr) => { $e.hash(state) } }
6320 let region = |state: &mut SipHasher, r: Region| {
6323 ReLateBound(db, BrAnon(i)) => {
6333 tcx.sess.bug("unexpected region found when hashing a type")
6337 let did = |state: &mut SipHasher, did: DefId| {
6338 let h = if ast_util::is_local(did) {
6341 tcx.sess.cstore.get_crate_hash(did.krate)
6343 h.as_str().hash(state);
6344 did.node.hash(state);
6346 let mt = |state: &mut SipHasher, mt: TypeAndMut| {
6347 mt.mutbl.hash(state);
6349 let fn_sig = |state: &mut SipHasher, sig: &Binder<FnSig<'tcx>>| {
6350 let sig = tcx.anonymize_late_bound_regions(sig).0;
6351 for a in &sig.inputs { helper(tcx, *a, svh, state); }
6352 if let ty::FnConverging(output) = sig.output {
6353 helper(tcx, output, svh, state);
6356 ty.maybe_walk(|ty| {
6398 TyBareFn(opt_def_id, ref b) => {
6403 fn_sig(state, &b.sig);
6406 TyTrait(ref data) => {
6408 did(state, data.principal_def_id());
6411 let principal = tcx.anonymize_late_bound_regions(&data.principal).0;
6412 for subty in &principal.substs.types {
6413 helper(tcx, subty, svh, state);
6422 TyTuple(ref inner) => {
6430 hash!(token::get_name(p.name));
6432 TyInfer(_) => unreachable!(),
6433 TyError => byte!(21),
6434 TyClosure(d, _) => {
6438 TyProjection(ref data) => {
6440 did(state, data.trait_ref.def_id);
6441 hash!(token::get_name(data.item_name));
6449 /// Construct a parameter environment suitable for static contexts or other contexts where there
6450 /// are no free type/lifetime parameters in scope.
6451 pub fn empty_parameter_environment<'a>(&'a self) -> ParameterEnvironment<'a,'tcx> {
6452 ty::ParameterEnvironment { tcx: self,
6453 free_substs: Substs::empty(),
6454 caller_bounds: Vec::new(),
6455 implicit_region_bound: ty::ReEmpty,
6456 selection_cache: traits::SelectionCache::new(), }
6459 /// Constructs and returns a substitution that can be applied to move from
6460 /// the "outer" view of a type or method to the "inner" view.
6461 /// In general, this means converting from bound parameters to
6462 /// free parameters. Since we currently represent bound/free type
6463 /// parameters in the same way, this only has an effect on regions.
6464 pub fn construct_free_substs(&self, generics: &Generics<'tcx>,
6465 free_id: ast::NodeId) -> Substs<'tcx> {
6467 let mut types = VecPerParamSpace::empty();
6468 for def in generics.types.as_slice() {
6469 debug!("construct_parameter_environment(): push_types_from_defs: def={:?}",
6471 types.push(def.space, self.mk_param_from_def(def));
6474 let free_id_outlive = region::DestructionScopeData::new(free_id);
6476 // map bound 'a => free 'a
6477 let mut regions = VecPerParamSpace::empty();
6478 for def in generics.regions.as_slice() {
6480 ReFree(FreeRegion { scope: free_id_outlive,
6481 bound_region: BrNamed(def.def_id, def.name) });
6482 debug!("push_region_params {:?}", region);
6483 regions.push(def.space, region);
6488 regions: subst::NonerasedRegions(regions)
6492 /// See `ParameterEnvironment` struct def'n for details
6493 pub fn construct_parameter_environment<'a>(&'a self,
6495 generics: &ty::Generics<'tcx>,
6496 generic_predicates: &ty::GenericPredicates<'tcx>,
6497 free_id: ast::NodeId)
6498 -> ParameterEnvironment<'a, 'tcx>
6501 // Construct the free substs.
6504 let free_substs = self.construct_free_substs(generics, free_id);
6505 let free_id_outlive = region::DestructionScopeData::new(free_id);
6508 // Compute the bounds on Self and the type parameters.
6511 let bounds = generic_predicates.instantiate(self, &free_substs);
6512 let bounds = self.liberate_late_bound_regions(free_id_outlive, &ty::Binder(bounds));
6513 let predicates = bounds.predicates.into_vec();
6515 debug!("construct_parameter_environment: free_id={:?} free_subst={:?} predicates={:?}",
6521 // Finally, we have to normalize the bounds in the environment, in
6522 // case they contain any associated type projections. This process
6523 // can yield errors if the put in illegal associated types, like
6524 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
6525 // report these errors right here; this doesn't actually feel
6526 // right to me, because constructing the environment feels like a
6527 // kind of a "idempotent" action, but I'm not sure where would be
6528 // a better place. In practice, we construct environments for
6529 // every fn once during type checking, and we'll abort if there
6530 // are any errors at that point, so after type checking you can be
6531 // sure that this will succeed without errors anyway.
6534 let unnormalized_env = ty::ParameterEnvironment {
6536 free_substs: free_substs,
6537 implicit_region_bound: ty::ReScope(free_id_outlive.to_code_extent()),
6538 caller_bounds: predicates,
6539 selection_cache: traits::SelectionCache::new(),
6542 let cause = traits::ObligationCause::misc(span, free_id);
6543 traits::normalize_param_env_or_error(unnormalized_env, cause)
6546 pub fn is_method_call(&self, expr_id: ast::NodeId) -> bool {
6547 self.tables.borrow().method_map.contains_key(&MethodCall::expr(expr_id))
6550 pub fn is_overloaded_autoderef(&self, expr_id: ast::NodeId, autoderefs: u32) -> bool {
6551 self.tables.borrow().method_map.contains_key(&MethodCall::autoderef(expr_id,
6555 pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture> {
6556 Some(self.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone())
6560 /// The category of explicit self.
6561 #[derive(Clone, Copy, Eq, PartialEq, Debug)]
6562 pub enum ExplicitSelfCategory {
6563 StaticExplicitSelfCategory,
6564 ByValueExplicitSelfCategory,
6565 ByReferenceExplicitSelfCategory(Region, ast::Mutability),
6566 ByBoxExplicitSelfCategory,
6569 /// A free variable referred to in a function.
6570 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
6571 pub struct Freevar {
6572 /// The variable being accessed free.
6575 // First span where it is accessed (there can be multiple).
6579 pub type FreevarMap = NodeMap<Vec<Freevar>>;
6581 pub type CaptureModeMap = NodeMap<ast::CaptureClause>;
6583 // Trait method resolution
6584 pub type TraitMap = NodeMap<Vec<DefId>>;
6586 // Map from the NodeId of a glob import to a list of items which are actually
6588 pub type GlobMap = HashMap<NodeId, HashSet<Name>>;
6590 impl<'tcx> AutoAdjustment<'tcx> {
6591 pub fn is_identity(&self) -> bool {
6593 AdjustReifyFnPointer |
6594 AdjustUnsafeFnPointer => false,
6595 AdjustDerefRef(ref r) => r.is_identity(),
6600 impl<'tcx> AutoDerefRef<'tcx> {
6601 pub fn is_identity(&self) -> bool {
6602 self.autoderefs == 0 && self.unsize.is_none() && self.autoref.is_none()
6606 impl<'tcx> ctxt<'tcx> {
6607 pub fn with_freevars<T, F>(&self, fid: ast::NodeId, f: F) -> T where
6608 F: FnOnce(&[Freevar]) -> T,
6610 match self.freevars.borrow().get(&fid) {
6612 Some(d) => f(&d[..])
6616 /// Replace any late-bound regions bound in `value` with free variants attached to scope-id
6618 pub fn liberate_late_bound_regions<T>(&self,
6619 all_outlive_scope: region::DestructionScopeData,
6622 where T : TypeFoldable<'tcx>
6624 ty_fold::replace_late_bound_regions(
6626 |br| ty::ReFree(ty::FreeRegion{scope: all_outlive_scope, bound_region: br})).0
6629 /// Flattens two binding levels into one. So `for<'a> for<'b> Foo`
6630 /// becomes `for<'a,'b> Foo`.
6631 pub fn flatten_late_bound_regions<T>(&self, bound2_value: &Binder<Binder<T>>)
6633 where T: TypeFoldable<'tcx>
6635 let bound0_value = bound2_value.skip_binder().skip_binder();
6636 let value = ty_fold::fold_regions(self, bound0_value, &mut false,
6637 |region, current_depth| {
6639 ty::ReLateBound(debruijn, br) if debruijn.depth >= current_depth => {
6640 // should be true if no escaping regions from bound2_value
6641 assert!(debruijn.depth - current_depth <= 1);
6642 ty::ReLateBound(DebruijnIndex::new(current_depth), br)
6652 pub fn no_late_bound_regions<T>(&self, value: &Binder<T>) -> Option<T>
6653 where T : TypeFoldable<'tcx> + RegionEscape
6655 if value.0.has_escaping_regions() {
6658 Some(value.0.clone())
6662 /// Replace any late-bound regions bound in `value` with `'static`. Useful in trans but also
6663 /// method lookup and a few other places where precise region relationships are not required.
6664 pub fn erase_late_bound_regions<T>(&self, value: &Binder<T>) -> T
6665 where T : TypeFoldable<'tcx>
6667 ty_fold::replace_late_bound_regions(self, value, |_| ty::ReStatic).0
6670 /// Rewrite any late-bound regions so that they are anonymous. Region numbers are
6671 /// assigned starting at 1 and increasing monotonically in the order traversed
6672 /// by the fold operation.
6674 /// The chief purpose of this function is to canonicalize regions so that two
6675 /// `FnSig`s or `TraitRef`s which are equivalent up to region naming will become
6676 /// structurally identical. For example, `for<'a, 'b> fn(&'a isize, &'b isize)` and
6677 /// `for<'a, 'b> fn(&'b isize, &'a isize)` will become identical after anonymization.
6678 pub fn anonymize_late_bound_regions<T>(&self, sig: &Binder<T>) -> Binder<T>
6679 where T : TypeFoldable<'tcx>,
6681 let mut counter = 0;
6682 ty::Binder(ty_fold::replace_late_bound_regions(self, sig, |_| {
6684 ReLateBound(ty::DebruijnIndex::new(1), BrAnon(counter))
6688 pub fn make_substs_for_receiver_types(&self,
6689 trait_ref: &ty::TraitRef<'tcx>,
6690 method: &ty::Method<'tcx>)
6691 -> subst::Substs<'tcx>
6694 * Substitutes the values for the receiver's type parameters
6695 * that are found in method, leaving the method's type parameters
6699 let meth_tps: Vec<Ty> =
6700 method.generics.types.get_slice(subst::FnSpace)
6702 .map(|def| self.mk_param_from_def(def))
6704 let meth_regions: Vec<ty::Region> =
6705 method.generics.regions.get_slice(subst::FnSpace)
6707 .map(|def| def.to_early_bound_region())
6709 trait_ref.substs.clone().with_method(meth_tps, meth_regions)
6713 impl DebruijnIndex {
6714 pub fn new(depth: u32) -> DebruijnIndex {
6716 DebruijnIndex { depth: depth }
6719 pub fn shifted(&self, amount: u32) -> DebruijnIndex {
6720 DebruijnIndex { depth: self.depth + amount }
6724 impl<'tcx> fmt::Debug for AutoAdjustment<'tcx> {
6725 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6727 AdjustReifyFnPointer => {
6728 write!(f, "AdjustReifyFnPointer")
6730 AdjustUnsafeFnPointer => {
6731 write!(f, "AdjustUnsafeFnPointer")
6733 AdjustDerefRef(ref data) => {
6734 write!(f, "{:?}", data)
6740 impl<'tcx> fmt::Debug for AutoDerefRef<'tcx> {
6741 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6742 write!(f, "AutoDerefRef({}, unsize={:?}, {:?})",
6743 self.autoderefs, self.unsize, self.autoref)
6747 impl<'tcx> fmt::Debug for TraitTy<'tcx> {
6748 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6749 write!(f, "TraitTy({:?},{:?})",
6755 impl<'tcx> fmt::Debug for ty::Predicate<'tcx> {
6756 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
6758 Predicate::Trait(ref a) => write!(f, "{:?}", a),
6759 Predicate::Equate(ref pair) => write!(f, "{:?}", pair),
6760 Predicate::RegionOutlives(ref pair) => write!(f, "{:?}", pair),
6761 Predicate::TypeOutlives(ref pair) => write!(f, "{:?}", pair),
6762 Predicate::Projection(ref pair) => write!(f, "{:?}", pair),
6767 // FIXME(#20298) -- all of these traits basically walk various
6768 // structures to test whether types/regions are reachable with various
6769 // properties. It should be possible to express them in terms of one
6770 // common "walker" trait or something.
6772 /// An "escaping region" is a bound region whose binder is not part of `t`.
6774 /// So, for example, consider a type like the following, which has two binders:
6776 /// for<'a> fn(x: for<'b> fn(&'a isize, &'b isize))
6777 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ outer scope
6778 /// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ inner scope
6780 /// This type has *bound regions* (`'a`, `'b`), but it does not have escaping regions, because the
6781 /// binders of both `'a` and `'b` are part of the type itself. However, if we consider the *inner
6782 /// fn type*, that type has an escaping region: `'a`.
6784 /// Note that what I'm calling an "escaping region" is often just called a "free region". However,
6785 /// we already use the term "free region". It refers to the regions that we use to represent bound
6786 /// regions on a fn definition while we are typechecking its body.
6788 /// To clarify, conceptually there is no particular difference between an "escaping" region and a
6789 /// "free" region. However, there is a big difference in practice. Basically, when "entering" a
6790 /// binding level, one is generally required to do some sort of processing to a bound region, such
6791 /// as replacing it with a fresh/skolemized region, or making an entry in the environment to
6792 /// represent the scope to which it is attached, etc. An escaping region represents a bound region
6793 /// for which this processing has not yet been done.
6794 pub trait RegionEscape {
6795 fn has_escaping_regions(&self) -> bool {
6796 self.has_regions_escaping_depth(0)
6799 fn has_regions_escaping_depth(&self, depth: u32) -> bool;
6802 impl<'tcx> RegionEscape for Ty<'tcx> {
6803 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6804 self.region_depth > depth
6808 impl<'tcx> RegionEscape for Substs<'tcx> {
6809 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6810 self.types.has_regions_escaping_depth(depth) ||
6811 self.regions.has_regions_escaping_depth(depth)
6815 impl<'tcx> RegionEscape for ClosureSubsts<'tcx> {
6816 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6817 self.func_substs.has_regions_escaping_depth(depth) ||
6818 self.upvar_tys.iter().any(|t| t.has_regions_escaping_depth(depth))
6822 impl<T:RegionEscape> RegionEscape for Vec<T> {
6823 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6824 self.iter().any(|t| t.has_regions_escaping_depth(depth))
6828 impl<'tcx> RegionEscape for FnSig<'tcx> {
6829 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6830 self.inputs.has_regions_escaping_depth(depth) ||
6831 self.output.has_regions_escaping_depth(depth)
6835 impl<'tcx,T:RegionEscape> RegionEscape for VecPerParamSpace<T> {
6836 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6837 self.iter_enumerated().any(|(space, _, t)| {
6838 if space == subst::FnSpace {
6839 t.has_regions_escaping_depth(depth+1)
6841 t.has_regions_escaping_depth(depth)
6847 impl<'tcx> RegionEscape for TypeScheme<'tcx> {
6848 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6849 self.ty.has_regions_escaping_depth(depth)
6853 impl RegionEscape for Region {
6854 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6855 self.escapes_depth(depth)
6859 impl<'tcx> RegionEscape for GenericPredicates<'tcx> {
6860 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6861 self.predicates.has_regions_escaping_depth(depth)
6865 impl<'tcx> RegionEscape for Predicate<'tcx> {
6866 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6868 Predicate::Trait(ref data) => data.has_regions_escaping_depth(depth),
6869 Predicate::Equate(ref data) => data.has_regions_escaping_depth(depth),
6870 Predicate::RegionOutlives(ref data) => data.has_regions_escaping_depth(depth),
6871 Predicate::TypeOutlives(ref data) => data.has_regions_escaping_depth(depth),
6872 Predicate::Projection(ref data) => data.has_regions_escaping_depth(depth),
6877 impl<'tcx,P:RegionEscape> RegionEscape for traits::Obligation<'tcx,P> {
6878 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6879 self.predicate.has_regions_escaping_depth(depth)
6883 impl<'tcx> RegionEscape for TraitRef<'tcx> {
6884 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6885 self.substs.types.iter().any(|t| t.has_regions_escaping_depth(depth)) ||
6886 self.substs.regions.has_regions_escaping_depth(depth)
6890 impl<'tcx> RegionEscape for subst::RegionSubsts {
6891 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6893 subst::ErasedRegions => false,
6894 subst::NonerasedRegions(ref r) => {
6895 r.iter().any(|t| t.has_regions_escaping_depth(depth))
6901 impl<'tcx,T:RegionEscape> RegionEscape for Binder<T> {
6902 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6903 self.0.has_regions_escaping_depth(depth + 1)
6907 impl<'tcx> RegionEscape for FnOutput<'tcx> {
6908 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6910 FnConverging(t) => t.has_regions_escaping_depth(depth),
6911 FnDiverging => false
6916 impl<'tcx> RegionEscape for EquatePredicate<'tcx> {
6917 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6918 self.0.has_regions_escaping_depth(depth) || self.1.has_regions_escaping_depth(depth)
6922 impl<'tcx> RegionEscape for TraitPredicate<'tcx> {
6923 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6924 self.trait_ref.has_regions_escaping_depth(depth)
6928 impl<T:RegionEscape,U:RegionEscape> RegionEscape for OutlivesPredicate<T,U> {
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 ProjectionPredicate<'tcx> {
6935 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6936 self.projection_ty.has_regions_escaping_depth(depth) ||
6937 self.ty.has_regions_escaping_depth(depth)
6941 impl<'tcx> RegionEscape for ProjectionTy<'tcx> {
6942 fn has_regions_escaping_depth(&self, depth: u32) -> bool {
6943 self.trait_ref.has_regions_escaping_depth(depth)
6947 pub trait HasTypeFlags {
6948 fn has_type_flags(&self, flags: TypeFlags) -> bool;
6949 fn has_projection_types(&self) -> bool {
6950 self.has_type_flags(TypeFlags::HAS_PROJECTION)
6952 fn references_error(&self) -> bool {
6953 self.has_type_flags(TypeFlags::HAS_TY_ERR)
6955 fn has_param_types(&self) -> bool {
6956 self.has_type_flags(TypeFlags::HAS_PARAMS)
6958 fn has_self_ty(&self) -> bool {
6959 self.has_type_flags(TypeFlags::HAS_SELF)
6961 fn has_infer_types(&self) -> bool {
6962 self.has_type_flags(TypeFlags::HAS_TY_INFER)
6964 fn needs_infer(&self) -> bool {
6965 self.has_type_flags(TypeFlags::HAS_TY_INFER | TypeFlags::HAS_RE_INFER)
6967 fn needs_subst(&self) -> bool {
6968 self.has_type_flags(TypeFlags::NEEDS_SUBST)
6970 fn has_closure_types(&self) -> bool {
6971 self.has_type_flags(TypeFlags::HAS_TY_CLOSURE)
6973 fn has_erasable_regions(&self) -> bool {
6974 self.has_type_flags(TypeFlags::HAS_RE_EARLY_BOUND |
6975 TypeFlags::HAS_RE_INFER |
6976 TypeFlags::HAS_FREE_REGIONS)
6978 /// Indicates whether this value references only 'global'
6979 /// types/lifetimes that are the same regardless of what fn we are
6980 /// in. This is used for caching. Errs on the side of returning
6982 fn is_global(&self) -> bool {
6983 !self.has_type_flags(TypeFlags::HAS_LOCAL_NAMES)
6987 impl<'tcx,T:HasTypeFlags> HasTypeFlags for Vec<T> {
6988 fn has_type_flags(&self, flags: TypeFlags) -> bool {
6989 self[..].has_type_flags(flags)
6993 impl<'tcx,T:HasTypeFlags> HasTypeFlags for [T] {
6994 fn has_type_flags(&self, flags: TypeFlags) -> bool {
6995 self.iter().any(|p| p.has_type_flags(flags))
6999 impl<'tcx,T:HasTypeFlags> HasTypeFlags for VecPerParamSpace<T> {
7000 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7001 self.iter().any(|p| p.has_type_flags(flags))
7005 impl<'tcx> HasTypeFlags for ClosureTy<'tcx> {
7006 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7007 self.sig.has_type_flags(flags)
7011 impl<'tcx> HasTypeFlags for ClosureUpvar<'tcx> {
7012 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7013 self.ty.has_type_flags(flags)
7017 impl<'tcx> HasTypeFlags for ty::InstantiatedPredicates<'tcx> {
7018 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7019 self.predicates.has_type_flags(flags)
7023 impl<'tcx> HasTypeFlags for Predicate<'tcx> {
7024 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7026 Predicate::Trait(ref data) => data.has_type_flags(flags),
7027 Predicate::Equate(ref data) => data.has_type_flags(flags),
7028 Predicate::RegionOutlives(ref data) => data.has_type_flags(flags),
7029 Predicate::TypeOutlives(ref data) => data.has_type_flags(flags),
7030 Predicate::Projection(ref data) => data.has_type_flags(flags),
7035 impl<'tcx> HasTypeFlags for TraitPredicate<'tcx> {
7036 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7037 self.trait_ref.has_type_flags(flags)
7041 impl<'tcx> HasTypeFlags for EquatePredicate<'tcx> {
7042 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7043 self.0.has_type_flags(flags) || self.1.has_type_flags(flags)
7047 impl HasTypeFlags for Region {
7048 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7049 if flags.intersects(TypeFlags::HAS_LOCAL_NAMES) {
7050 // does this represent a region that cannot be named in a global
7051 // way? used in fulfillment caching.
7053 ty::ReStatic | ty::ReEmpty => {}
7057 if flags.intersects(TypeFlags::HAS_RE_INFER) {
7058 if let ty::ReInfer(_) = *self {
7066 impl<T:HasTypeFlags,U:HasTypeFlags> HasTypeFlags for OutlivesPredicate<T,U> {
7067 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7068 self.0.has_type_flags(flags) || self.1.has_type_flags(flags)
7072 impl<'tcx> HasTypeFlags for ProjectionPredicate<'tcx> {
7073 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7074 self.projection_ty.has_type_flags(flags) || self.ty.has_type_flags(flags)
7078 impl<'tcx> HasTypeFlags for ProjectionTy<'tcx> {
7079 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7080 self.trait_ref.has_type_flags(flags)
7084 impl<'tcx> HasTypeFlags for Ty<'tcx> {
7085 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7086 self.flags.get().intersects(flags)
7090 impl<'tcx> HasTypeFlags for TraitRef<'tcx> {
7091 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7092 self.substs.has_type_flags(flags)
7096 impl<'tcx> HasTypeFlags for subst::Substs<'tcx> {
7097 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7098 self.types.has_type_flags(flags) || match self.regions {
7099 subst::ErasedRegions => false,
7100 subst::NonerasedRegions(ref r) => r.has_type_flags(flags)
7105 impl<'tcx,T> HasTypeFlags for Option<T>
7106 where T : HasTypeFlags
7108 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7109 self.iter().any(|t| t.has_type_flags(flags))
7113 impl<'tcx,T> HasTypeFlags for Rc<T>
7114 where T : HasTypeFlags
7116 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7117 (**self).has_type_flags(flags)
7121 impl<'tcx,T> HasTypeFlags for Box<T>
7122 where T : HasTypeFlags
7124 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7125 (**self).has_type_flags(flags)
7129 impl<T> HasTypeFlags for Binder<T>
7130 where T : HasTypeFlags
7132 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7133 self.0.has_type_flags(flags)
7137 impl<'tcx> HasTypeFlags for FnOutput<'tcx> {
7138 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7140 FnConverging(t) => t.has_type_flags(flags),
7141 FnDiverging => false,
7146 impl<'tcx> HasTypeFlags for FnSig<'tcx> {
7147 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7148 self.inputs.iter().any(|t| t.has_type_flags(flags)) ||
7149 self.output.has_type_flags(flags)
7153 impl<'tcx> HasTypeFlags for Field<'tcx> {
7154 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7155 self.mt.ty.has_type_flags(flags)
7159 impl<'tcx> HasTypeFlags for BareFnTy<'tcx> {
7160 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7161 self.sig.has_type_flags(flags)
7165 impl<'tcx> HasTypeFlags for ClosureSubsts<'tcx> {
7166 fn has_type_flags(&self, flags: TypeFlags) -> bool {
7167 self.func_substs.has_type_flags(flags) ||
7168 self.upvar_tys.iter().any(|t| t.has_type_flags(flags))
7172 impl<'tcx> fmt::Debug for ClosureTy<'tcx> {
7173 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7174 write!(f, "ClosureTy({},{:?},{})",
7181 impl<'tcx> fmt::Debug for ClosureUpvar<'tcx> {
7182 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7183 write!(f, "ClosureUpvar({:?},{:?})",
7189 impl<'tcx> fmt::Debug for Field<'tcx> {
7190 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7191 write!(f, "field({},{})", self.name, self.mt)
7195 impl<'a, 'tcx> fmt::Debug for ParameterEnvironment<'a, 'tcx> {
7196 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7197 write!(f, "ParameterEnvironment(\
7199 implicit_region_bound={:?}, \
7200 caller_bounds={:?})",
7202 self.implicit_region_bound,
7207 impl<'tcx> fmt::Debug for ObjectLifetimeDefault {
7208 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
7210 ObjectLifetimeDefault::Ambiguous => write!(f, "Ambiguous"),
7211 ObjectLifetimeDefault::BaseDefault => write!(f, "BaseDefault"),
7212 ObjectLifetimeDefault::Specific(ref r) => write!(f, "{:?}", r),