1 use crate::def::{CtorKind, DefKind, Res};
2 use crate::def_id::DefId;
3 pub(crate) use crate::hir_id::{HirId, ItemLocalId};
4 use crate::intravisit::FnKind;
8 use rustc_ast::util::parser::ExprPrecedence;
9 use rustc_ast::{Attribute, FloatTy, IntTy, Label, LitKind, TraitObjectSyntax, UintTy};
10 pub use rustc_ast::{BorrowKind, ImplPolarity, IsAuto};
11 pub use rustc_ast::{CaptureBy, Movability, Mutability};
12 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
13 use rustc_data_structures::fingerprint::Fingerprint;
14 use rustc_data_structures::fx::FxHashMap;
15 use rustc_data_structures::sorted_map::SortedMap;
16 use rustc_error_messages::MultiSpan;
17 use rustc_index::vec::IndexVec;
18 use rustc_macros::HashStable_Generic;
19 use rustc_span::hygiene::MacroKind;
20 use rustc_span::source_map::Spanned;
21 use rustc_span::symbol::{kw, sym, Ident, Symbol};
22 use rustc_span::{def_id::LocalDefId, BytePos, Span, DUMMY_SP};
23 use rustc_target::asm::InlineAsmRegOrRegClass;
24 use rustc_target::spec::abi::Abi;
26 use smallvec::SmallVec;
29 #[derive(Debug, Copy, Clone, Encodable, HashStable_Generic)]
34 /// Either "`'a`", referring to a named lifetime definition,
35 /// or "``" (i.e., `kw::Empty`), for elision placeholders.
37 /// HIR lowering inserts these placeholders in type paths that
38 /// refer to type definitions needing lifetime parameters,
39 /// `&T` and `&mut T`, and trait objects without `... + 'a`.
40 pub name: LifetimeName,
43 #[derive(Debug, Clone, PartialEq, Eq, Encodable, Hash, Copy)]
44 #[derive(HashStable_Generic)]
46 /// Some user-given name like `T` or `'x`.
49 /// Synthetic name generated when user elided a lifetime in an impl header.
51 /// E.g., the lifetimes in cases like these:
52 /// ```ignore (fragment)
54 /// impl Foo<'_> for u32
56 /// in that case, we rewrite to
57 /// ```ignore (fragment)
58 /// impl<'f> Foo for &'f u32
59 /// impl<'f> Foo<'f> for u32
61 /// where `'f` is something like `Fresh(0)`. The indices are
62 /// unique per impl, but not necessarily continuous.
65 /// Indicates an illegal name was given and an error has been
66 /// reported (so we should squelch other derived errors). Occurs
67 /// when, e.g., `'_` is used in the wrong place.
72 pub fn ident(&self) -> Ident {
74 ParamName::Plain(ident) => ident,
75 ParamName::Fresh | ParamName::Error => Ident::with_dummy_span(kw::UnderscoreLifetime),
79 pub fn normalize_to_macros_2_0(&self) -> ParamName {
81 ParamName::Plain(ident) => ParamName::Plain(ident.normalize_to_macros_2_0()),
82 param_name => param_name,
87 #[derive(Debug, Clone, PartialEq, Eq, Encodable, Hash, Copy)]
88 #[derive(HashStable_Generic)]
89 pub enum LifetimeName {
90 /// User-given names or fresh (synthetic) names.
91 Param(LocalDefId, ParamName),
93 /// User wrote nothing (e.g., the lifetime in `&u32`).
96 /// Implicit lifetime in a context like `dyn Foo`. This is
97 /// distinguished from implicit lifetimes elsewhere because the
98 /// lifetime that they default to must appear elsewhere within the
99 /// enclosing type. This means that, in an `impl Trait` context, we
100 /// don't have to create a parameter for them. That is, `impl
101 /// Trait<Item = &u32>` expands to an opaque type like `type
102 /// Foo<'a> = impl Trait<Item = &'a u32>`, but `impl Trait<item =
103 /// dyn Bar>` expands to `type Foo = impl Trait<Item = dyn Bar +
104 /// 'static>`. The latter uses `ImplicitObjectLifetimeDefault` so
105 /// that surrounding code knows not to create a lifetime
107 ImplicitObjectLifetimeDefault,
109 /// Indicates an error during lowering (usually `'_` in wrong place)
110 /// that was already reported.
113 /// User wrote specifies `'_`.
116 /// User wrote `'static`.
121 pub fn ident(&self) -> Ident {
123 LifetimeName::ImplicitObjectLifetimeDefault
124 | LifetimeName::Implicit
125 | LifetimeName::Error => Ident::empty(),
126 LifetimeName::Underscore => Ident::with_dummy_span(kw::UnderscoreLifetime),
127 LifetimeName::Static => Ident::with_dummy_span(kw::StaticLifetime),
128 LifetimeName::Param(_, param_name) => param_name.ident(),
132 pub fn is_anonymous(&self) -> bool {
134 LifetimeName::ImplicitObjectLifetimeDefault
135 | LifetimeName::Implicit
136 | LifetimeName::Underscore
137 | LifetimeName::Param(_, ParamName::Fresh)
138 | LifetimeName::Error => true,
139 LifetimeName::Static | LifetimeName::Param(..) => false,
143 pub fn is_elided(&self) -> bool {
145 LifetimeName::ImplicitObjectLifetimeDefault
146 | LifetimeName::Implicit
147 | LifetimeName::Underscore => true,
149 // It might seem surprising that `Fresh` counts as
150 // *not* elided -- but this is because, as far as the code
151 // in the compiler is concerned -- `Fresh` variants act
152 // equivalently to "some fresh name". They correspond to
153 // early-bound regions on an impl, in other words.
154 LifetimeName::Error | LifetimeName::Param(..) | LifetimeName::Static => false,
158 fn is_static(&self) -> bool {
159 self == &LifetimeName::Static
162 pub fn normalize_to_macros_2_0(&self) -> LifetimeName {
164 LifetimeName::Param(def_id, param_name) => {
165 LifetimeName::Param(def_id, param_name.normalize_to_macros_2_0())
167 lifetime_name => lifetime_name,
172 impl fmt::Display for Lifetime {
173 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
174 self.name.ident().fmt(f)
179 pub fn is_elided(&self) -> bool {
180 self.name.is_elided()
183 pub fn is_static(&self) -> bool {
184 self.name.is_static()
188 /// A `Path` is essentially Rust's notion of a name; for instance,
189 /// `std::cmp::PartialEq`. It's represented as a sequence of identifiers,
190 /// along with a bunch of supporting information.
191 #[derive(Debug, HashStable_Generic)]
192 pub struct Path<'hir> {
194 /// The resolution for the path.
196 /// The segments in the path: the things separated by `::`.
197 pub segments: &'hir [PathSegment<'hir>],
201 pub fn is_global(&self) -> bool {
202 !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
206 /// A segment of a path: an identifier, an optional lifetime, and a set of
208 #[derive(Debug, HashStable_Generic)]
209 pub struct PathSegment<'hir> {
210 /// The identifier portion of this path segment.
212 // `id` and `res` are optional. We currently only use these in save-analysis,
213 // any path segments without these will not have save-analysis info and
214 // therefore will not have 'jump to def' in IDEs, but otherwise will not be
215 // affected. (In general, we don't bother to get the defs for synthesized
216 // segments, only for segments which have come from the AST).
217 pub hir_id: Option<HirId>,
218 pub res: Option<Res>,
220 /// Type/lifetime parameters attached to this path. They come in
221 /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`. Note that
222 /// this is more than just simple syntactic sugar; the use of
223 /// parens affects the region binding rules, so we preserve the
225 pub args: Option<&'hir GenericArgs<'hir>>,
227 /// Whether to infer remaining type parameters, if any.
228 /// This only applies to expression and pattern paths, and
229 /// out of those only the segments with no type parameters
230 /// to begin with, e.g., `Vec::new` is `<Vec<..>>::new::<..>`.
231 pub infer_args: bool,
234 impl<'hir> PathSegment<'hir> {
235 /// Converts an identifier to the corresponding segment.
236 pub fn from_ident(ident: Ident) -> PathSegment<'hir> {
237 PathSegment { ident, hir_id: None, res: None, infer_args: true, args: None }
240 pub fn invalid() -> Self {
241 Self::from_ident(Ident::empty())
244 pub fn args(&self) -> &GenericArgs<'hir> {
245 if let Some(ref args) = self.args {
248 const DUMMY: &GenericArgs<'_> = &GenericArgs::none();
254 #[derive(Encodable, Debug, HashStable_Generic)]
255 pub struct ConstArg {
256 pub value: AnonConst,
260 #[derive(Encodable, Debug, HashStable_Generic)]
261 pub struct InferArg {
267 pub fn to_ty(&self) -> Ty<'_> {
268 Ty { kind: TyKind::Infer, span: self.span, hir_id: self.hir_id }
272 #[derive(Debug, HashStable_Generic)]
273 pub enum GenericArg<'hir> {
280 impl GenericArg<'_> {
281 pub fn span(&self) -> Span {
283 GenericArg::Lifetime(l) => l.span,
284 GenericArg::Type(t) => t.span,
285 GenericArg::Const(c) => c.span,
286 GenericArg::Infer(i) => i.span,
290 pub fn id(&self) -> HirId {
292 GenericArg::Lifetime(l) => l.hir_id,
293 GenericArg::Type(t) => t.hir_id,
294 GenericArg::Const(c) => c.value.hir_id,
295 GenericArg::Infer(i) => i.hir_id,
299 pub fn is_synthetic(&self) -> bool {
300 matches!(self, GenericArg::Lifetime(lifetime) if lifetime.name.ident() == Ident::empty())
303 pub fn descr(&self) -> &'static str {
305 GenericArg::Lifetime(_) => "lifetime",
306 GenericArg::Type(_) => "type",
307 GenericArg::Const(_) => "constant",
308 GenericArg::Infer(_) => "inferred",
312 pub fn to_ord(&self) -> ast::ParamKindOrd {
314 GenericArg::Lifetime(_) => ast::ParamKindOrd::Lifetime,
315 GenericArg::Type(_) => ast::ParamKindOrd::Type,
316 GenericArg::Const(_) => ast::ParamKindOrd::Const,
317 GenericArg::Infer(_) => ast::ParamKindOrd::Infer,
321 pub fn is_ty_or_const(&self) -> bool {
323 GenericArg::Lifetime(_) => false,
324 GenericArg::Type(_) | GenericArg::Const(_) | GenericArg::Infer(_) => true,
329 #[derive(Debug, HashStable_Generic)]
330 pub struct GenericArgs<'hir> {
331 /// The generic arguments for this path segment.
332 pub args: &'hir [GenericArg<'hir>],
333 /// Bindings (equality constraints) on associated types, if present.
334 /// E.g., `Foo<A = Bar>`.
335 pub bindings: &'hir [TypeBinding<'hir>],
336 /// Were arguments written in parenthesized form `Fn(T) -> U`?
337 /// This is required mostly for pretty-printing and diagnostics,
338 /// but also for changing lifetime elision rules to be "function-like".
339 pub parenthesized: bool,
340 /// The span encompassing arguments and the surrounding brackets `<>` or `()`
341 /// Foo<A, B, AssocTy = D> Fn(T, U, V) -> W
342 /// ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^
343 /// Note that this may be:
344 /// - empty, if there are no generic brackets (but there may be hidden lifetimes)
345 /// - dummy, if this was generated while desugaring
349 impl<'hir> GenericArgs<'hir> {
350 pub const fn none() -> Self {
351 Self { args: &[], bindings: &[], parenthesized: false, span_ext: DUMMY_SP }
354 pub fn inputs(&self) -> &[Ty<'hir>] {
355 if self.parenthesized {
356 for arg in self.args {
358 GenericArg::Lifetime(_) => {}
359 GenericArg::Type(ref ty) => {
360 if let TyKind::Tup(ref tys) = ty.kind {
365 GenericArg::Const(_) => {}
366 GenericArg::Infer(_) => {}
370 panic!("GenericArgs::inputs: not a `Fn(T) -> U`");
374 pub fn has_type_params(&self) -> bool {
375 self.args.iter().any(|arg| matches!(arg, GenericArg::Type(_)))
378 pub fn has_err(&self) -> bool {
379 self.args.iter().any(|arg| match arg {
380 GenericArg::Type(ty) => matches!(ty.kind, TyKind::Err),
382 }) || self.bindings.iter().any(|arg| match arg.kind {
383 TypeBindingKind::Equality { term: Term::Ty(ty) } => matches!(ty.kind, TyKind::Err),
389 pub fn num_type_params(&self) -> usize {
390 self.args.iter().filter(|arg| matches!(arg, GenericArg::Type(_))).count()
394 pub fn num_lifetime_params(&self) -> usize {
395 self.args.iter().filter(|arg| matches!(arg, GenericArg::Lifetime(_))).count()
399 pub fn has_lifetime_params(&self) -> bool {
400 self.args.iter().any(|arg| matches!(arg, GenericArg::Lifetime(_)))
404 pub fn num_generic_params(&self) -> usize {
405 self.args.iter().filter(|arg| !matches!(arg, GenericArg::Lifetime(_))).count()
408 /// The span encompassing the text inside the surrounding brackets.
409 /// It will also include bindings if they aren't in the form `-> Ret`
410 /// Returns `None` if the span is empty (e.g. no brackets) or dummy
411 pub fn span(&self) -> Option<Span> {
412 let span_ext = self.span_ext()?;
413 Some(span_ext.with_lo(span_ext.lo() + BytePos(1)).with_hi(span_ext.hi() - BytePos(1)))
416 /// Returns span encompassing arguments and their surrounding `<>` or `()`
417 pub fn span_ext(&self) -> Option<Span> {
418 Some(self.span_ext).filter(|span| !span.is_empty())
421 pub fn is_empty(&self) -> bool {
426 /// A modifier on a bound, currently this is only used for `?Sized`, where the
427 /// modifier is `Maybe`. Negative bounds should also be handled here.
428 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Hash, Debug)]
429 #[derive(HashStable_Generic)]
430 pub enum TraitBoundModifier {
436 /// The AST represents all type param bounds as types.
437 /// `typeck::collect::compute_bounds` matches these against
438 /// the "special" built-in traits (see `middle::lang_items`) and
439 /// detects `Copy`, `Send` and `Sync`.
440 #[derive(Clone, Debug, HashStable_Generic)]
441 pub enum GenericBound<'hir> {
442 Trait(PolyTraitRef<'hir>, TraitBoundModifier),
443 // FIXME(davidtwco): Introduce `PolyTraitRef::LangItem`
444 LangItemTrait(LangItem, Span, HirId, &'hir GenericArgs<'hir>),
448 impl GenericBound<'_> {
449 pub fn trait_ref(&self) -> Option<&TraitRef<'_>> {
451 GenericBound::Trait(data, _) => Some(&data.trait_ref),
456 pub fn span(&self) -> Span {
458 GenericBound::Trait(t, ..) => t.span,
459 GenericBound::LangItemTrait(_, span, ..) => *span,
460 GenericBound::Outlives(l) => l.span,
465 pub type GenericBounds<'hir> = &'hir [GenericBound<'hir>];
467 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Debug, HashStable_Generic)]
468 pub enum LifetimeParamKind {
469 // Indicates that the lifetime definition was explicitly declared (e.g., in
470 // `fn foo<'a>(x: &'a u8) -> &'a u8 { x }`).
473 // Indication that the lifetime was elided (e.g., in both cases in
474 // `fn foo(x: &u8) -> &'_ u8 { x }`).
477 // Indication that the lifetime name was somehow in error.
481 #[derive(Debug, HashStable_Generic)]
482 pub enum GenericParamKind<'hir> {
483 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
485 kind: LifetimeParamKind,
488 default: Option<&'hir Ty<'hir>>,
493 /// Optional default value for the const generic param
494 default: Option<AnonConst>,
498 #[derive(Debug, HashStable_Generic)]
499 pub struct GenericParam<'hir> {
503 pub pure_wrt_drop: bool,
504 pub kind: GenericParamKind<'hir>,
505 pub colon_span: Option<Span>,
508 impl<'hir> GenericParam<'hir> {
509 /// Synthetic type-parameters are inserted after normal ones.
510 /// In order for normal parameters to be able to refer to synthetic ones,
511 /// scans them first.
512 pub fn is_impl_trait(&self) -> bool {
513 matches!(self.kind, GenericParamKind::Type { synthetic: true, .. })
516 /// This can happen for `async fn`, e.g. `async fn f<'_>(&'_ self)`.
518 /// See `lifetime_to_generic_param` in `rustc_ast_lowering` for more information.
519 pub fn is_elided_lifetime(&self) -> bool {
520 matches!(self.kind, GenericParamKind::Lifetime { kind: LifetimeParamKind::Elided })
525 pub struct GenericParamCount {
526 pub lifetimes: usize,
532 /// Represents lifetimes and type parameters attached to a declaration
533 /// of a function, enum, trait, etc.
534 #[derive(Debug, HashStable_Generic)]
535 pub struct Generics<'hir> {
536 pub params: &'hir [GenericParam<'hir>],
537 pub predicates: &'hir [WherePredicate<'hir>],
538 pub has_where_clause_predicates: bool,
539 pub where_clause_span: Span,
543 impl<'hir> Generics<'hir> {
544 pub const fn empty() -> &'hir Generics<'hir> {
545 const NOPE: Generics<'_> = Generics {
548 has_where_clause_predicates: false,
549 where_clause_span: DUMMY_SP,
555 pub fn get_named(&self, name: Symbol) -> Option<&GenericParam<'hir>> {
556 for param in self.params {
557 if name == param.name.ident().name {
564 pub fn spans(&self) -> MultiSpan {
565 if self.params.is_empty() {
568 self.params.iter().map(|p| p.span).collect::<Vec<Span>>().into()
572 /// If there are generic parameters, return where to introduce a new one.
573 pub fn span_for_param_suggestion(&self) -> Option<Span> {
574 if self.params.iter().any(|p| self.span.contains(p.span)) {
575 // `fn foo<A>(t: impl Trait)`
576 // ^ suggest `, T: Trait` here
577 let span = self.span.with_lo(self.span.hi() - BytePos(1)).shrink_to_lo();
584 /// `Span` where further predicates would be suggested, accounting for trailing commas, like
585 /// in `fn foo<T>(t: T) where T: Foo,` so we don't suggest two trailing commas.
586 pub fn tail_span_for_predicate_suggestion(&self) -> Span {
587 let end = self.where_clause_span.shrink_to_hi();
588 if self.has_where_clause_predicates {
591 .filter(|p| p.in_where_clause())
593 .map_or(end, |p| p.span())
601 pub fn add_where_or_trailing_comma(&self) -> &'static str {
602 if self.has_where_clause_predicates {
604 } else if self.where_clause_span.is_empty() {
607 // No where clause predicates, but we have `where` token
612 pub fn bounds_for_param(
614 param_def_id: LocalDefId,
615 ) -> impl Iterator<Item = &WhereBoundPredicate<'hir>> {
616 self.predicates.iter().filter_map(move |pred| match pred {
617 WherePredicate::BoundPredicate(bp) if bp.is_param_bound(param_def_id.to_def_id()) => {
624 pub fn outlives_for_param(
626 param_def_id: LocalDefId,
627 ) -> impl Iterator<Item = &WhereRegionPredicate<'_>> {
628 self.predicates.iter().filter_map(move |pred| match pred {
629 WherePredicate::RegionPredicate(rp) if rp.is_param_bound(param_def_id) => Some(rp),
634 pub fn bounds_span_for_suggestions(&self, param_def_id: LocalDefId) -> Option<Span> {
635 self.bounds_for_param(param_def_id).flat_map(|bp| bp.bounds.iter().rev()).find_map(
637 // We include bounds that come from a `#[derive(_)]` but point at the user's code,
638 // as we use this method to get a span appropriate for suggestions.
639 let bs = bound.span();
640 if bs.can_be_used_for_suggestions() { Some(bs.shrink_to_hi()) } else { None }
645 pub fn span_for_predicate_removal(&self, pos: usize) -> Span {
646 let predicate = &self.predicates[pos];
647 let span = predicate.span();
649 if !predicate.in_where_clause() {
655 // We need to find out which comma to remove.
656 if pos < self.predicates.len() - 1 {
657 let next_pred = &self.predicates[pos + 1];
658 if next_pred.in_where_clause() {
659 // where T: ?Sized, Foo: Bar,
661 return span.until(next_pred.span());
666 let prev_pred = &self.predicates[pos - 1];
667 if prev_pred.in_where_clause() {
668 // where Foo: Bar, T: ?Sized,
670 return prev_pred.span().shrink_to_hi().to(span);
674 // This is the only predicate in the where clause.
677 self.where_clause_span
680 pub fn span_for_bound_removal(&self, predicate_pos: usize, bound_pos: usize) -> Span {
681 let predicate = &self.predicates[predicate_pos];
682 let bounds = predicate.bounds();
684 if bounds.len() == 1 {
685 return self.span_for_predicate_removal(predicate_pos);
688 let span = bounds[bound_pos].span();
690 // where T: ?Sized + Bar, Foo: Bar,
692 span.to(bounds[1].span().shrink_to_lo())
694 // where T: Bar + ?Sized, Foo: Bar,
696 bounds[bound_pos - 1].span().shrink_to_hi().to(span)
701 /// A single predicate in a where-clause.
702 #[derive(Debug, HashStable_Generic)]
703 pub enum WherePredicate<'hir> {
704 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
705 BoundPredicate(WhereBoundPredicate<'hir>),
706 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
707 RegionPredicate(WhereRegionPredicate<'hir>),
708 /// An equality predicate (unsupported).
709 EqPredicate(WhereEqPredicate<'hir>),
712 impl<'hir> WherePredicate<'hir> {
713 pub fn span(&self) -> Span {
715 WherePredicate::BoundPredicate(p) => p.span,
716 WherePredicate::RegionPredicate(p) => p.span,
717 WherePredicate::EqPredicate(p) => p.span,
721 pub fn in_where_clause(&self) -> bool {
723 WherePredicate::BoundPredicate(p) => p.origin == PredicateOrigin::WhereClause,
724 WherePredicate::RegionPredicate(p) => p.in_where_clause,
725 WherePredicate::EqPredicate(_) => false,
729 pub fn bounds(&self) -> GenericBounds<'hir> {
731 WherePredicate::BoundPredicate(p) => p.bounds,
732 WherePredicate::RegionPredicate(p) => p.bounds,
733 WherePredicate::EqPredicate(_) => &[],
738 #[derive(Copy, Clone, Debug, HashStable_Generic, PartialEq, Eq)]
739 pub enum PredicateOrigin {
745 /// A type bound (e.g., `for<'c> Foo: Send + Clone + 'c`).
746 #[derive(Debug, HashStable_Generic)]
747 pub struct WhereBoundPredicate<'hir> {
749 /// Origin of the predicate.
750 pub origin: PredicateOrigin,
751 /// Any generics from a `for` binding.
752 pub bound_generic_params: &'hir [GenericParam<'hir>],
753 /// The type being bounded.
754 pub bounded_ty: &'hir Ty<'hir>,
755 /// Trait and lifetime bounds (e.g., `Clone + Send + 'static`).
756 pub bounds: GenericBounds<'hir>,
759 impl<'hir> WhereBoundPredicate<'hir> {
760 /// Returns `true` if `param_def_id` matches the `bounded_ty` of this predicate.
761 pub fn is_param_bound(&self, param_def_id: DefId) -> bool {
762 self.bounded_ty.as_generic_param().map_or(false, |(def_id, _)| def_id == param_def_id)
766 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
767 #[derive(Debug, HashStable_Generic)]
768 pub struct WhereRegionPredicate<'hir> {
770 pub in_where_clause: bool,
771 pub lifetime: Lifetime,
772 pub bounds: GenericBounds<'hir>,
775 impl<'hir> WhereRegionPredicate<'hir> {
776 /// Returns `true` if `param_def_id` matches the `lifetime` of this predicate.
777 pub fn is_param_bound(&self, param_def_id: LocalDefId) -> bool {
778 match self.lifetime.name {
779 LifetimeName::Param(id, _) => id == param_def_id,
785 /// An equality predicate (e.g., `T = int`); currently unsupported.
786 #[derive(Debug, HashStable_Generic)]
787 pub struct WhereEqPredicate<'hir> {
790 pub lhs_ty: &'hir Ty<'hir>,
791 pub rhs_ty: &'hir Ty<'hir>,
794 /// HIR node coupled with its parent's id in the same HIR owner.
796 /// The parent is trash when the node is a HIR owner.
797 #[derive(Clone, Debug)]
798 pub struct ParentedNode<'tcx> {
799 pub parent: ItemLocalId,
800 pub node: Node<'tcx>,
803 /// Attributes owned by a HIR owner.
805 pub struct AttributeMap<'tcx> {
806 pub map: SortedMap<ItemLocalId, &'tcx [Attribute]>,
807 pub hash: Fingerprint,
810 impl<'tcx> AttributeMap<'tcx> {
811 pub const EMPTY: &'static AttributeMap<'static> =
812 &AttributeMap { map: SortedMap::new(), hash: Fingerprint::ZERO };
815 pub fn get(&self, id: ItemLocalId) -> &'tcx [Attribute] {
816 self.map.get(&id).copied().unwrap_or(&[])
820 /// Map of all HIR nodes inside the current owner.
821 /// These nodes are mapped by `ItemLocalId` alongside the index of their parent node.
822 /// The HIR tree, including bodies, is pre-hashed.
823 pub struct OwnerNodes<'tcx> {
824 /// Pre-computed hash of the full HIR.
825 pub hash_including_bodies: Fingerprint,
826 /// Pre-computed hash of the item signature, sithout recursing into the body.
827 pub hash_without_bodies: Fingerprint,
828 /// Full HIR for the current owner.
829 // The zeroth node's parent should never be accessed: the owner's parent is computed by the
830 // hir_owner_parent query. It is set to `ItemLocalId::INVALID` to force an ICE if accidentally
832 pub nodes: IndexVec<ItemLocalId, Option<ParentedNode<'tcx>>>,
833 /// Content of local bodies.
834 pub bodies: SortedMap<ItemLocalId, &'tcx Body<'tcx>>,
835 /// Non-owning definitions contained in this owner.
836 pub local_id_to_def_id: SortedMap<ItemLocalId, LocalDefId>,
839 impl<'tcx> OwnerNodes<'tcx> {
840 pub fn node(&self) -> OwnerNode<'tcx> {
841 use rustc_index::vec::Idx;
842 let node = self.nodes[ItemLocalId::new(0)].as_ref().unwrap().node;
843 let node = node.as_owner().unwrap(); // Indexing must ensure it is an OwnerNode.
848 impl fmt::Debug for OwnerNodes<'_> {
849 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
850 f.debug_struct("OwnerNodes")
851 .field("node", &self.nodes[ItemLocalId::from_u32(0)])
852 .field("bodies", &self.bodies)
853 .field("local_id_to_def_id", &self.local_id_to_def_id)
854 .field("hash_without_bodies", &self.hash_without_bodies)
855 .field("hash_including_bodies", &self.hash_including_bodies)
860 /// Full information resulting from lowering an AST node.
861 #[derive(Debug, HashStable_Generic)]
862 pub struct OwnerInfo<'hir> {
863 /// Contents of the HIR.
864 pub nodes: OwnerNodes<'hir>,
865 /// Map from each nested owner to its parent's local id.
866 pub parenting: FxHashMap<LocalDefId, ItemLocalId>,
867 /// Collected attributes of the HIR nodes.
868 pub attrs: AttributeMap<'hir>,
869 /// Map indicating what traits are in scope for places where this
870 /// is relevant; generated by resolve.
871 pub trait_map: FxHashMap<ItemLocalId, Box<[TraitCandidate]>>,
874 impl<'tcx> OwnerInfo<'tcx> {
876 pub fn node(&self) -> OwnerNode<'tcx> {
881 #[derive(Copy, Clone, Debug, HashStable_Generic)]
882 pub enum MaybeOwner<T> {
885 /// Used as a placeholder for unused LocalDefId.
889 impl<T> MaybeOwner<T> {
890 pub fn as_owner(self) -> Option<T> {
892 MaybeOwner::Owner(i) => Some(i),
893 MaybeOwner::NonOwner(_) | MaybeOwner::Phantom => None,
897 pub fn map<U>(self, f: impl FnOnce(T) -> U) -> MaybeOwner<U> {
899 MaybeOwner::Owner(i) => MaybeOwner::Owner(f(i)),
900 MaybeOwner::NonOwner(hir_id) => MaybeOwner::NonOwner(hir_id),
901 MaybeOwner::Phantom => MaybeOwner::Phantom,
905 pub fn unwrap(self) -> T {
907 MaybeOwner::Owner(i) => i,
908 MaybeOwner::NonOwner(_) | MaybeOwner::Phantom => panic!("Not a HIR owner"),
913 /// The top-level data structure that stores the entire contents of
914 /// the crate currently being compiled.
916 /// For more details, see the [rustc dev guide].
918 /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
920 pub struct Crate<'hir> {
921 pub owners: IndexVec<LocalDefId, MaybeOwner<&'hir OwnerInfo<'hir>>>,
922 pub hir_hash: Fingerprint,
925 #[derive(Debug, HashStable_Generic)]
926 pub struct Closure<'hir> {
927 pub binder: ClosureBinder,
928 pub capture_clause: CaptureBy,
929 pub bound_generic_params: &'hir [GenericParam<'hir>],
930 pub fn_decl: &'hir FnDecl<'hir>,
932 pub fn_decl_span: Span,
933 pub movability: Option<Movability>,
936 /// A block of statements `{ .. }`, which may have a label (in this case the
937 /// `targeted_by_break` field will be `true`) and may be `unsafe` by means of
938 /// the `rules` being anything but `DefaultBlock`.
939 #[derive(Debug, HashStable_Generic)]
940 pub struct Block<'hir> {
941 /// Statements in a block.
942 pub stmts: &'hir [Stmt<'hir>],
943 /// An expression at the end of the block
944 /// without a semicolon, if any.
945 pub expr: Option<&'hir Expr<'hir>>,
946 #[stable_hasher(ignore)]
948 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
949 pub rules: BlockCheckMode,
951 /// If true, then there may exist `break 'a` values that aim to
952 /// break out of this block early.
953 /// Used by `'label: {}` blocks and by `try {}` blocks.
954 pub targeted_by_break: bool,
957 #[derive(Debug, HashStable_Generic)]
958 pub struct Pat<'hir> {
959 #[stable_hasher(ignore)]
961 pub kind: PatKind<'hir>,
963 // Whether to use default binding modes.
964 // At present, this is false only for destructuring assignment.
965 pub default_binding_modes: bool,
968 impl<'hir> Pat<'hir> {
969 // FIXME(#19596) this is a workaround, but there should be a better way
970 fn walk_short_(&self, it: &mut impl FnMut(&Pat<'hir>) -> bool) -> bool {
977 Wild | Lit(_) | Range(..) | Binding(.., None) | Path(_) => true,
978 Box(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_short_(it),
979 Struct(_, fields, _) => fields.iter().all(|field| field.pat.walk_short_(it)),
980 TupleStruct(_, s, _) | Tuple(s, _) | Or(s) => s.iter().all(|p| p.walk_short_(it)),
981 Slice(before, slice, after) => {
982 before.iter().chain(slice).chain(after.iter()).all(|p| p.walk_short_(it))
987 /// Walk the pattern in left-to-right order,
988 /// short circuiting (with `.all(..)`) if `false` is returned.
990 /// Note that when visiting e.g. `Tuple(ps)`,
991 /// if visiting `ps[0]` returns `false`,
992 /// then `ps[1]` will not be visited.
993 pub fn walk_short(&self, mut it: impl FnMut(&Pat<'hir>) -> bool) -> bool {
994 self.walk_short_(&mut it)
997 // FIXME(#19596) this is a workaround, but there should be a better way
998 fn walk_(&self, it: &mut impl FnMut(&Pat<'hir>) -> bool) {
1005 Wild | Lit(_) | Range(..) | Binding(.., None) | Path(_) => {}
1006 Box(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_(it),
1007 Struct(_, fields, _) => fields.iter().for_each(|field| field.pat.walk_(it)),
1008 TupleStruct(_, s, _) | Tuple(s, _) | Or(s) => s.iter().for_each(|p| p.walk_(it)),
1009 Slice(before, slice, after) => {
1010 before.iter().chain(slice).chain(after.iter()).for_each(|p| p.walk_(it))
1015 /// Walk the pattern in left-to-right order.
1017 /// If `it(pat)` returns `false`, the children are not visited.
1018 pub fn walk(&self, mut it: impl FnMut(&Pat<'hir>) -> bool) {
1022 /// Walk the pattern in left-to-right order.
1024 /// If you always want to recurse, prefer this method over `walk`.
1025 pub fn walk_always(&self, mut it: impl FnMut(&Pat<'_>)) {
1033 /// A single field in a struct pattern.
1035 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
1036 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
1037 /// except `is_shorthand` is true.
1038 #[derive(Debug, HashStable_Generic)]
1039 pub struct PatField<'hir> {
1040 #[stable_hasher(ignore)]
1042 /// The identifier for the field.
1044 /// The pattern the field is destructured to.
1045 pub pat: &'hir Pat<'hir>,
1046 pub is_shorthand: bool,
1050 /// Explicit binding annotations given in the HIR for a binding. Note
1051 /// that this is not the final binding *mode* that we infer after type
1053 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
1054 pub enum BindingAnnotation {
1055 /// No binding annotation given: this means that the final binding mode
1056 /// will depend on whether we have skipped through a `&` reference
1057 /// when matching. For example, the `x` in `Some(x)` will have binding
1058 /// mode `None`; if you do `let Some(x) = &Some(22)`, it will
1059 /// ultimately be inferred to be by-reference.
1061 /// Note that implicit reference skipping is not implemented yet (#42640).
1064 /// Annotated with `mut x` -- could be either ref or not, similar to `None`.
1067 /// Annotated as `ref`, like `ref x`
1070 /// Annotated as `ref mut x`.
1074 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
1080 impl fmt::Display for RangeEnd {
1081 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1082 f.write_str(match self {
1083 RangeEnd::Included => "..=",
1084 RangeEnd::Excluded => "..",
1089 #[derive(Debug, HashStable_Generic)]
1090 pub enum PatKind<'hir> {
1091 /// Represents a wildcard pattern (i.e., `_`).
1094 /// A fresh binding `ref mut binding @ OPT_SUBPATTERN`.
1095 /// The `HirId` is the canonical ID for the variable being bound,
1096 /// (e.g., in `Ok(x) | Err(x)`, both `x` use the same canonical ID),
1097 /// which is the pattern ID of the first `x`.
1098 Binding(BindingAnnotation, HirId, Ident, Option<&'hir Pat<'hir>>),
1100 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
1101 /// The `bool` is `true` in the presence of a `..`.
1102 Struct(QPath<'hir>, &'hir [PatField<'hir>], bool),
1104 /// A tuple struct/variant pattern `Variant(x, y, .., z)`.
1105 /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
1106 /// `0 <= position <= subpats.len()`
1107 TupleStruct(QPath<'hir>, &'hir [Pat<'hir>], Option<usize>),
1109 /// An or-pattern `A | B | C`.
1110 /// Invariant: `pats.len() >= 2`.
1111 Or(&'hir [Pat<'hir>]),
1113 /// A path pattern for a unit struct/variant or a (maybe-associated) constant.
1116 /// A tuple pattern (e.g., `(a, b)`).
1117 /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
1118 /// `0 <= position <= subpats.len()`
1119 Tuple(&'hir [Pat<'hir>], Option<usize>),
1121 /// A `box` pattern.
1122 Box(&'hir Pat<'hir>),
1124 /// A reference pattern (e.g., `&mut (a, b)`).
1125 Ref(&'hir Pat<'hir>, Mutability),
1128 Lit(&'hir Expr<'hir>),
1130 /// A range pattern (e.g., `1..=2` or `1..2`).
1131 Range(Option<&'hir Expr<'hir>>, Option<&'hir Expr<'hir>>, RangeEnd),
1133 /// A slice pattern, `[before_0, ..., before_n, (slice, after_0, ..., after_n)?]`.
1135 /// Here, `slice` is lowered from the syntax `($binding_mode $ident @)? ..`.
1136 /// If `slice` exists, then `after` can be non-empty.
1138 /// The representation for e.g., `[a, b, .., c, d]` is:
1139 /// ```ignore (illustrative)
1140 /// PatKind::Slice([Binding(a), Binding(b)], Some(Wild), [Binding(c), Binding(d)])
1142 Slice(&'hir [Pat<'hir>], Option<&'hir Pat<'hir>>, &'hir [Pat<'hir>]),
1145 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
1146 pub enum BinOpKind {
1147 /// The `+` operator (addition).
1149 /// The `-` operator (subtraction).
1151 /// The `*` operator (multiplication).
1153 /// The `/` operator (division).
1155 /// The `%` operator (modulus).
1157 /// The `&&` operator (logical and).
1159 /// The `||` operator (logical or).
1161 /// The `^` operator (bitwise xor).
1163 /// The `&` operator (bitwise and).
1165 /// The `|` operator (bitwise or).
1167 /// The `<<` operator (shift left).
1169 /// The `>>` operator (shift right).
1171 /// The `==` operator (equality).
1173 /// The `<` operator (less than).
1175 /// The `<=` operator (less than or equal to).
1177 /// The `!=` operator (not equal to).
1179 /// The `>=` operator (greater than or equal to).
1181 /// The `>` operator (greater than).
1186 pub fn as_str(self) -> &'static str {
1188 BinOpKind::Add => "+",
1189 BinOpKind::Sub => "-",
1190 BinOpKind::Mul => "*",
1191 BinOpKind::Div => "/",
1192 BinOpKind::Rem => "%",
1193 BinOpKind::And => "&&",
1194 BinOpKind::Or => "||",
1195 BinOpKind::BitXor => "^",
1196 BinOpKind::BitAnd => "&",
1197 BinOpKind::BitOr => "|",
1198 BinOpKind::Shl => "<<",
1199 BinOpKind::Shr => ">>",
1200 BinOpKind::Eq => "==",
1201 BinOpKind::Lt => "<",
1202 BinOpKind::Le => "<=",
1203 BinOpKind::Ne => "!=",
1204 BinOpKind::Ge => ">=",
1205 BinOpKind::Gt => ">",
1209 pub fn is_lazy(self) -> bool {
1210 matches!(self, BinOpKind::And | BinOpKind::Or)
1213 pub fn is_shift(self) -> bool {
1214 matches!(self, BinOpKind::Shl | BinOpKind::Shr)
1217 pub fn is_comparison(self) -> bool {
1224 | BinOpKind::Ge => true,
1236 | BinOpKind::Shr => false,
1240 /// Returns `true` if the binary operator takes its arguments by value.
1241 pub fn is_by_value(self) -> bool {
1242 !self.is_comparison()
1246 impl Into<ast::BinOpKind> for BinOpKind {
1247 fn into(self) -> ast::BinOpKind {
1249 BinOpKind::Add => ast::BinOpKind::Add,
1250 BinOpKind::Sub => ast::BinOpKind::Sub,
1251 BinOpKind::Mul => ast::BinOpKind::Mul,
1252 BinOpKind::Div => ast::BinOpKind::Div,
1253 BinOpKind::Rem => ast::BinOpKind::Rem,
1254 BinOpKind::And => ast::BinOpKind::And,
1255 BinOpKind::Or => ast::BinOpKind::Or,
1256 BinOpKind::BitXor => ast::BinOpKind::BitXor,
1257 BinOpKind::BitAnd => ast::BinOpKind::BitAnd,
1258 BinOpKind::BitOr => ast::BinOpKind::BitOr,
1259 BinOpKind::Shl => ast::BinOpKind::Shl,
1260 BinOpKind::Shr => ast::BinOpKind::Shr,
1261 BinOpKind::Eq => ast::BinOpKind::Eq,
1262 BinOpKind::Lt => ast::BinOpKind::Lt,
1263 BinOpKind::Le => ast::BinOpKind::Le,
1264 BinOpKind::Ne => ast::BinOpKind::Ne,
1265 BinOpKind::Ge => ast::BinOpKind::Ge,
1266 BinOpKind::Gt => ast::BinOpKind::Gt,
1271 pub type BinOp = Spanned<BinOpKind>;
1273 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
1275 /// The `*` operator (dereferencing).
1277 /// The `!` operator (logical negation).
1279 /// The `-` operator (negation).
1284 pub fn as_str(self) -> &'static str {
1292 /// Returns `true` if the unary operator takes its argument by value.
1293 pub fn is_by_value(self) -> bool {
1294 matches!(self, Self::Neg | Self::Not)
1299 #[derive(Debug, HashStable_Generic)]
1300 pub struct Stmt<'hir> {
1302 pub kind: StmtKind<'hir>,
1306 /// The contents of a statement.
1307 #[derive(Debug, HashStable_Generic)]
1308 pub enum StmtKind<'hir> {
1309 /// A local (`let`) binding.
1310 Local(&'hir Local<'hir>),
1312 /// An item binding.
1315 /// An expression without a trailing semi-colon (must have unit type).
1316 Expr(&'hir Expr<'hir>),
1318 /// An expression with a trailing semi-colon (may have any type).
1319 Semi(&'hir Expr<'hir>),
1322 /// Represents a `let` statement (i.e., `let <pat>:<ty> = <expr>;`).
1323 #[derive(Debug, HashStable_Generic)]
1324 pub struct Local<'hir> {
1325 pub pat: &'hir Pat<'hir>,
1326 /// Type annotation, if any (otherwise the type will be inferred).
1327 pub ty: Option<&'hir Ty<'hir>>,
1328 /// Initializer expression to set the value, if any.
1329 pub init: Option<&'hir Expr<'hir>>,
1330 /// Else block for a `let...else` binding.
1331 pub els: Option<&'hir Block<'hir>>,
1334 /// Can be `ForLoopDesugar` if the `let` statement is part of a `for` loop
1335 /// desugaring. Otherwise will be `Normal`.
1336 pub source: LocalSource,
1339 /// Represents a single arm of a `match` expression, e.g.
1340 /// `<pat> (if <guard>) => <body>`.
1341 #[derive(Debug, HashStable_Generic)]
1342 pub struct Arm<'hir> {
1343 #[stable_hasher(ignore)]
1346 /// If this pattern and the optional guard matches, then `body` is evaluated.
1347 pub pat: &'hir Pat<'hir>,
1348 /// Optional guard clause.
1349 pub guard: Option<Guard<'hir>>,
1350 /// The expression the arm evaluates to if this arm matches.
1351 pub body: &'hir Expr<'hir>,
1354 /// Represents a `let <pat>[: <ty>] = <expr>` expression (not a Local), occurring in an `if-let` or
1355 /// `let-else`, evaluating to a boolean. Typically the pattern is refutable.
1357 /// In an if-let, imagine it as `if (let <pat> = <expr>) { ... }`; in a let-else, it is part of the
1358 /// desugaring to if-let. Only let-else supports the type annotation at present.
1359 #[derive(Debug, HashStable_Generic)]
1360 pub struct Let<'hir> {
1363 pub pat: &'hir Pat<'hir>,
1364 pub ty: Option<&'hir Ty<'hir>>,
1365 pub init: &'hir Expr<'hir>,
1368 #[derive(Debug, HashStable_Generic)]
1369 pub enum Guard<'hir> {
1370 If(&'hir Expr<'hir>),
1371 IfLet(&'hir Let<'hir>),
1374 impl<'hir> Guard<'hir> {
1375 /// Returns the body of the guard
1377 /// In other words, returns the e in either of the following:
1380 /// - `if let x = e`
1381 pub fn body(&self) -> &'hir Expr<'hir> {
1383 Guard::If(e) | Guard::IfLet(Let { init: e, .. }) => e,
1388 #[derive(Debug, HashStable_Generic)]
1389 pub struct ExprField<'hir> {
1390 #[stable_hasher(ignore)]
1393 pub expr: &'hir Expr<'hir>,
1395 pub is_shorthand: bool,
1398 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
1399 pub enum BlockCheckMode {
1401 UnsafeBlock(UnsafeSource),
1404 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
1405 pub enum UnsafeSource {
1410 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
1415 /// The body of a function, closure, or constant value. In the case of
1416 /// a function, the body contains not only the function body itself
1417 /// (which is an expression), but also the argument patterns, since
1418 /// those are something that the caller doesn't really care about.
1423 /// fn foo((x, y): (u32, u32)) -> u32 {
1428 /// Here, the `Body` associated with `foo()` would contain:
1430 /// - an `params` array containing the `(x, y)` pattern
1431 /// - a `value` containing the `x + y` expression (maybe wrapped in a block)
1432 /// - `generator_kind` would be `None`
1434 /// All bodies have an **owner**, which can be accessed via the HIR
1435 /// map using `body_owner_def_id()`.
1436 #[derive(Debug, HashStable_Generic)]
1437 pub struct Body<'hir> {
1438 pub params: &'hir [Param<'hir>],
1439 pub value: Expr<'hir>,
1440 pub generator_kind: Option<GeneratorKind>,
1443 impl<'hir> Body<'hir> {
1444 pub fn id(&self) -> BodyId {
1445 BodyId { hir_id: self.value.hir_id }
1448 pub fn generator_kind(&self) -> Option<GeneratorKind> {
1453 /// The type of source expression that caused this generator to be created.
1454 #[derive(Clone, PartialEq, PartialOrd, Eq, Hash, Debug, Copy)]
1455 #[derive(HashStable_Generic, Encodable, Decodable)]
1456 pub enum GeneratorKind {
1457 /// An explicit `async` block or the body of an async function.
1458 Async(AsyncGeneratorKind),
1460 /// A generator literal created via a `yield` inside a closure.
1464 impl fmt::Display for GeneratorKind {
1465 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1467 GeneratorKind::Async(k) => fmt::Display::fmt(k, f),
1468 GeneratorKind::Gen => f.write_str("generator"),
1473 impl GeneratorKind {
1474 pub fn descr(&self) -> &'static str {
1476 GeneratorKind::Async(ask) => ask.descr(),
1477 GeneratorKind::Gen => "generator",
1482 /// In the case of a generator created as part of an async construct,
1483 /// which kind of async construct caused it to be created?
1485 /// This helps error messages but is also used to drive coercions in
1486 /// type-checking (see #60424).
1487 #[derive(Clone, PartialEq, PartialOrd, Eq, Hash, Debug, Copy)]
1488 #[derive(HashStable_Generic, Encodable, Decodable)]
1489 pub enum AsyncGeneratorKind {
1490 /// An explicit `async` block written by the user.
1493 /// An explicit `async` closure written by the user.
1496 /// The `async` block generated as the body of an async function.
1500 impl fmt::Display for AsyncGeneratorKind {
1501 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1502 f.write_str(match self {
1503 AsyncGeneratorKind::Block => "`async` block",
1504 AsyncGeneratorKind::Closure => "`async` closure body",
1505 AsyncGeneratorKind::Fn => "`async fn` body",
1510 impl AsyncGeneratorKind {
1511 pub fn descr(&self) -> &'static str {
1513 AsyncGeneratorKind::Block => "`async` block",
1514 AsyncGeneratorKind::Closure => "`async` closure body",
1515 AsyncGeneratorKind::Fn => "`async fn` body",
1520 #[derive(Copy, Clone, Debug)]
1521 pub enum BodyOwnerKind {
1522 /// Functions and methods.
1528 /// Constants and associated constants.
1531 /// Initializer of a `static` item.
1535 impl BodyOwnerKind {
1536 pub fn is_fn_or_closure(self) -> bool {
1538 BodyOwnerKind::Fn | BodyOwnerKind::Closure => true,
1539 BodyOwnerKind::Const | BodyOwnerKind::Static(_) => false,
1544 /// The kind of an item that requires const-checking.
1545 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
1546 pub enum ConstContext {
1550 /// A `static` or `static mut`.
1553 /// A `const`, associated `const`, or other const context.
1555 /// Other contexts include:
1556 /// - Array length expressions
1557 /// - Enum discriminants
1558 /// - Const generics
1560 /// For the most part, other contexts are treated just like a regular `const`, so they are
1561 /// lumped into the same category.
1566 /// A description of this const context that can appear between backticks in an error message.
1568 /// E.g. `const` or `static mut`.
1569 pub fn keyword_name(self) -> &'static str {
1571 Self::Const => "const",
1572 Self::Static(Mutability::Not) => "static",
1573 Self::Static(Mutability::Mut) => "static mut",
1574 Self::ConstFn => "const fn",
1579 /// A colloquial, trivially pluralizable description of this const context for use in error
1581 impl fmt::Display for ConstContext {
1582 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1584 Self::Const => write!(f, "constant"),
1585 Self::Static(_) => write!(f, "static"),
1586 Self::ConstFn => write!(f, "constant function"),
1591 // NOTE: `IntoDiagnosticArg` impl for `ConstContext` lives in `rustc_errors`
1592 // due to a cyclical dependency between hir that crate.
1595 pub type Lit = Spanned<LitKind>;
1597 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Debug, HashStable_Generic)]
1604 pub fn hir_id(&self) -> HirId {
1606 &ArrayLen::Infer(hir_id, _) | &ArrayLen::Body(AnonConst { hir_id, body: _ }) => hir_id,
1611 /// A constant (expression) that's not an item or associated item,
1612 /// but needs its own `DefId` for type-checking, const-eval, etc.
1613 /// These are usually found nested inside types (e.g., array lengths)
1614 /// or expressions (e.g., repeat counts), and also used to define
1615 /// explicit discriminant values for enum variants.
1617 /// You can check if this anon const is a default in a const param
1618 /// `const N: usize = { ... }` with `tcx.hir().opt_const_param_default_param_hir_id(..)`
1619 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Debug, HashStable_Generic)]
1620 pub struct AnonConst {
1627 pub struct Expr<'hir> {
1629 pub kind: ExprKind<'hir>,
1634 pub fn precedence(&self) -> ExprPrecedence {
1636 ExprKind::Box(_) => ExprPrecedence::Box,
1637 ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
1638 ExprKind::Array(_) => ExprPrecedence::Array,
1639 ExprKind::Call(..) => ExprPrecedence::Call,
1640 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1641 ExprKind::Tup(_) => ExprPrecedence::Tup,
1642 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node.into()),
1643 ExprKind::Unary(..) => ExprPrecedence::Unary,
1644 ExprKind::Lit(_) => ExprPrecedence::Lit,
1645 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1646 ExprKind::DropTemps(ref expr, ..) => expr.precedence(),
1647 ExprKind::If(..) => ExprPrecedence::If,
1648 ExprKind::Let(..) => ExprPrecedence::Let,
1649 ExprKind::Loop(..) => ExprPrecedence::Loop,
1650 ExprKind::Match(..) => ExprPrecedence::Match,
1651 ExprKind::Closure { .. } => ExprPrecedence::Closure,
1652 ExprKind::Block(..) => ExprPrecedence::Block,
1653 ExprKind::Assign(..) => ExprPrecedence::Assign,
1654 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1655 ExprKind::Field(..) => ExprPrecedence::Field,
1656 ExprKind::Index(..) => ExprPrecedence::Index,
1657 ExprKind::Path(..) => ExprPrecedence::Path,
1658 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1659 ExprKind::Break(..) => ExprPrecedence::Break,
1660 ExprKind::Continue(..) => ExprPrecedence::Continue,
1661 ExprKind::Ret(..) => ExprPrecedence::Ret,
1662 ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
1663 ExprKind::Struct(..) => ExprPrecedence::Struct,
1664 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1665 ExprKind::Yield(..) => ExprPrecedence::Yield,
1666 ExprKind::Err => ExprPrecedence::Err,
1670 // Whether this looks like a place expr, without checking for deref
1672 // This will return `true` in some potentially surprising cases such as
1673 // `CONSTANT.field`.
1674 pub fn is_syntactic_place_expr(&self) -> bool {
1675 self.is_place_expr(|_| true)
1678 /// Whether this is a place expression.
1680 /// `allow_projections_from` should return `true` if indexing a field or index expression based
1681 /// on the given expression should be considered a place expression.
1682 pub fn is_place_expr(&self, mut allow_projections_from: impl FnMut(&Self) -> bool) -> bool {
1684 ExprKind::Path(QPath::Resolved(_, ref path)) => {
1685 matches!(path.res, Res::Local(..) | Res::Def(DefKind::Static(_), _) | Res::Err)
1688 // Type ascription inherits its place expression kind from its
1690 // https://github.com/rust-lang/rfcs/blob/master/text/0803-type-ascription.md#type-ascription-and-temporaries
1691 ExprKind::Type(ref e, _) => e.is_place_expr(allow_projections_from),
1693 ExprKind::Unary(UnOp::Deref, _) => true,
1695 ExprKind::Field(ref base, _) | ExprKind::Index(ref base, _) => {
1696 allow_projections_from(base) || base.is_place_expr(allow_projections_from)
1699 // Lang item paths cannot currently be local variables or statics.
1700 ExprKind::Path(QPath::LangItem(..)) => false,
1702 // Partially qualified paths in expressions can only legally
1703 // refer to associated items which are always rvalues.
1704 ExprKind::Path(QPath::TypeRelative(..))
1705 | ExprKind::Call(..)
1706 | ExprKind::MethodCall(..)
1707 | ExprKind::Struct(..)
1710 | ExprKind::Match(..)
1711 | ExprKind::Closure { .. }
1712 | ExprKind::Block(..)
1713 | ExprKind::Repeat(..)
1714 | ExprKind::Array(..)
1715 | ExprKind::Break(..)
1716 | ExprKind::Continue(..)
1719 | ExprKind::Loop(..)
1720 | ExprKind::Assign(..)
1721 | ExprKind::InlineAsm(..)
1722 | ExprKind::AssignOp(..)
1724 | ExprKind::ConstBlock(..)
1725 | ExprKind::Unary(..)
1727 | ExprKind::AddrOf(..)
1728 | ExprKind::Binary(..)
1729 | ExprKind::Yield(..)
1730 | ExprKind::Cast(..)
1731 | ExprKind::DropTemps(..)
1732 | ExprKind::Err => false,
1736 /// If `Self.kind` is `ExprKind::DropTemps(expr)`, drill down until we get a non-`DropTemps`
1737 /// `Expr`. This is used in suggestions to ignore this `ExprKind` as it is semantically
1738 /// silent, only signaling the ownership system. By doing this, suggestions that check the
1739 /// `ExprKind` of any given `Expr` for presentation don't have to care about `DropTemps`
1740 /// beyond remembering to call this function before doing analysis on it.
1741 pub fn peel_drop_temps(&self) -> &Self {
1742 let mut expr = self;
1743 while let ExprKind::DropTemps(inner) = &expr.kind {
1749 pub fn peel_blocks(&self) -> &Self {
1750 let mut expr = self;
1751 while let ExprKind::Block(Block { expr: Some(inner), .. }, _) = &expr.kind {
1757 pub fn can_have_side_effects(&self) -> bool {
1758 match self.peel_drop_temps().kind {
1759 ExprKind::Path(_) | ExprKind::Lit(_) => false,
1760 ExprKind::Type(base, _)
1761 | ExprKind::Unary(_, base)
1762 | ExprKind::Field(base, _)
1763 | ExprKind::Index(base, _)
1764 | ExprKind::AddrOf(.., base)
1765 | ExprKind::Cast(base, _) => {
1766 // This isn't exactly true for `Index` and all `Unary`, but we are using this
1767 // method exclusively for diagnostics and there's a *cultural* pressure against
1768 // them being used only for its side-effects.
1769 base.can_have_side_effects()
1771 ExprKind::Struct(_, fields, init) => fields
1773 .map(|field| field.expr)
1774 .chain(init.into_iter())
1775 .all(|e| e.can_have_side_effects()),
1777 ExprKind::Array(args)
1778 | ExprKind::Tup(args)
1782 ExprKind::Path(QPath::Resolved(
1784 Path { res: Res::Def(DefKind::Ctor(_, CtorKind::Fn), _), .. },
1789 ) => args.iter().all(|arg| arg.can_have_side_effects()),
1791 | ExprKind::Match(..)
1792 | ExprKind::MethodCall(..)
1793 | ExprKind::Call(..)
1794 | ExprKind::Closure { .. }
1795 | ExprKind::Block(..)
1796 | ExprKind::Repeat(..)
1797 | ExprKind::Break(..)
1798 | ExprKind::Continue(..)
1801 | ExprKind::Loop(..)
1802 | ExprKind::Assign(..)
1803 | ExprKind::InlineAsm(..)
1804 | ExprKind::AssignOp(..)
1805 | ExprKind::ConstBlock(..)
1807 | ExprKind::Binary(..)
1808 | ExprKind::Yield(..)
1809 | ExprKind::DropTemps(..)
1810 | ExprKind::Err => true,
1814 // To a first-order approximation, is this a pattern
1815 pub fn is_approximately_pattern(&self) -> bool {
1818 | ExprKind::Array(_)
1819 | ExprKind::Call(..)
1823 | ExprKind::Struct(..) => true,
1828 pub fn method_ident(&self) -> Option<Ident> {
1830 ExprKind::MethodCall(receiver_method, ..) => Some(receiver_method.ident),
1831 ExprKind::Unary(_, expr) | ExprKind::AddrOf(.., expr) => expr.method_ident(),
1837 /// Checks if the specified expression is a built-in range literal.
1838 /// (See: `LoweringContext::lower_expr()`).
1839 pub fn is_range_literal(expr: &Expr<'_>) -> bool {
1841 // All built-in range literals but `..=` and `..` desugar to `Struct`s.
1842 ExprKind::Struct(ref qpath, _, _) => matches!(
1847 | LangItem::RangeFrom
1848 | LangItem::RangeFull
1849 | LangItem::RangeToInclusive,
1854 // `..=` desugars into `::std::ops::RangeInclusive::new(...)`.
1855 ExprKind::Call(ref func, _) => {
1856 matches!(func.kind, ExprKind::Path(QPath::LangItem(LangItem::RangeInclusiveNew, ..)))
1863 #[derive(Debug, HashStable_Generic)]
1864 pub enum ExprKind<'hir> {
1865 /// A `box x` expression.
1866 Box(&'hir Expr<'hir>),
1867 /// Allow anonymous constants from an inline `const` block
1868 ConstBlock(AnonConst),
1869 /// An array (e.g., `[a, b, c, d]`).
1870 Array(&'hir [Expr<'hir>]),
1871 /// A function call.
1873 /// The first field resolves to the function itself (usually an `ExprKind::Path`),
1874 /// and the second field is the list of arguments.
1875 /// This also represents calling the constructor of
1876 /// tuple-like ADTs such as tuple structs and enum variants.
1877 Call(&'hir Expr<'hir>, &'hir [Expr<'hir>]),
1878 /// A method call (e.g., `x.foo::<'static, Bar, Baz>(a, b, c, d)`).
1880 /// The `PathSegment` represents the method name and its generic arguments
1881 /// (within the angle brackets).
1882 /// The first element of the `&[Expr]` is the expression that evaluates
1883 /// to the object on which the method is being called on (the receiver),
1884 /// and the remaining elements are the rest of the arguments.
1885 /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1886 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d], span)`.
1887 /// The final `Span` represents the span of the function and arguments
1888 /// (e.g. `foo::<Bar, Baz>(a, b, c, d)` in `x.foo::<Bar, Baz>(a, b, c, d)`
1890 /// To resolve the called method to a `DefId`, call [`type_dependent_def_id`] with
1891 /// the `hir_id` of the `MethodCall` node itself.
1893 /// [`type_dependent_def_id`]: ../../rustc_middle/ty/struct.TypeckResults.html#method.type_dependent_def_id
1894 MethodCall(&'hir PathSegment<'hir>, &'hir [Expr<'hir>], Span),
1895 /// A tuple (e.g., `(a, b, c, d)`).
1896 Tup(&'hir [Expr<'hir>]),
1897 /// A binary operation (e.g., `a + b`, `a * b`).
1898 Binary(BinOp, &'hir Expr<'hir>, &'hir Expr<'hir>),
1899 /// A unary operation (e.g., `!x`, `*x`).
1900 Unary(UnOp, &'hir Expr<'hir>),
1901 /// A literal (e.g., `1`, `"foo"`).
1903 /// A cast (e.g., `foo as f64`).
1904 Cast(&'hir Expr<'hir>, &'hir Ty<'hir>),
1905 /// A type reference (e.g., `Foo`).
1906 Type(&'hir Expr<'hir>, &'hir Ty<'hir>),
1907 /// Wraps the expression in a terminating scope.
1908 /// This makes it semantically equivalent to `{ let _t = expr; _t }`.
1910 /// This construct only exists to tweak the drop order in HIR lowering.
1911 /// An example of that is the desugaring of `for` loops.
1912 DropTemps(&'hir Expr<'hir>),
1913 /// A `let $pat = $expr` expression.
1915 /// These are not `Local` and only occur as expressions.
1916 /// The `let Some(x) = foo()` in `if let Some(x) = foo()` is an example of `Let(..)`.
1917 Let(&'hir Let<'hir>),
1918 /// An `if` block, with an optional else block.
1920 /// I.e., `if <expr> { <expr> } else { <expr> }`.
1921 If(&'hir Expr<'hir>, &'hir Expr<'hir>, Option<&'hir Expr<'hir>>),
1922 /// A conditionless loop (can be exited with `break`, `continue`, or `return`).
1924 /// I.e., `'label: loop { <block> }`.
1926 /// The `Span` is the loop header (`for x in y`/`while let pat = expr`).
1927 Loop(&'hir Block<'hir>, Option<Label>, LoopSource, Span),
1928 /// A `match` block, with a source that indicates whether or not it is
1929 /// the result of a desugaring, and if so, which kind.
1930 Match(&'hir Expr<'hir>, &'hir [Arm<'hir>], MatchSource),
1931 /// A closure (e.g., `move |a, b, c| {a + b + c}`).
1933 /// The `Span` is the argument block `|...|`.
1935 /// This may also be a generator literal or an `async block` as indicated by the
1936 /// `Option<Movability>`.
1937 Closure(&'hir Closure<'hir>),
1938 /// A block (e.g., `'label: { ... }`).
1939 Block(&'hir Block<'hir>, Option<Label>),
1941 /// An assignment (e.g., `a = foo()`).
1942 Assign(&'hir Expr<'hir>, &'hir Expr<'hir>, Span),
1943 /// An assignment with an operator.
1946 AssignOp(BinOp, &'hir Expr<'hir>, &'hir Expr<'hir>),
1947 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct or tuple field.
1948 Field(&'hir Expr<'hir>, Ident),
1949 /// An indexing operation (`foo[2]`).
1950 Index(&'hir Expr<'hir>, &'hir Expr<'hir>),
1952 /// Path to a definition, possibly containing lifetime or type parameters.
1955 /// A referencing operation (i.e., `&a` or `&mut a`).
1956 AddrOf(BorrowKind, Mutability, &'hir Expr<'hir>),
1957 /// A `break`, with an optional label to break.
1958 Break(Destination, Option<&'hir Expr<'hir>>),
1959 /// A `continue`, with an optional label.
1960 Continue(Destination),
1961 /// A `return`, with an optional value to be returned.
1962 Ret(Option<&'hir Expr<'hir>>),
1964 /// Inline assembly (from `asm!`), with its outputs and inputs.
1965 InlineAsm(&'hir InlineAsm<'hir>),
1967 /// A struct or struct-like variant literal expression.
1969 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. base}`,
1970 /// where `base` is the `Option<Expr>`.
1971 Struct(&'hir QPath<'hir>, &'hir [ExprField<'hir>], Option<&'hir Expr<'hir>>),
1973 /// An array literal constructed from one repeated element.
1975 /// E.g., `[1; 5]`. The first expression is the element
1976 /// to be repeated; the second is the number of times to repeat it.
1977 Repeat(&'hir Expr<'hir>, ArrayLen),
1979 /// A suspension point for generators (i.e., `yield <expr>`).
1980 Yield(&'hir Expr<'hir>, YieldSource),
1982 /// A placeholder for an expression that wasn't syntactically well formed in some way.
1986 /// Represents an optionally `Self`-qualified value/type path or associated extension.
1988 /// To resolve the path to a `DefId`, call [`qpath_res`].
1990 /// [`qpath_res`]: ../../rustc_middle/ty/struct.TypeckResults.html#method.qpath_res
1991 #[derive(Debug, HashStable_Generic)]
1992 pub enum QPath<'hir> {
1993 /// Path to a definition, optionally "fully-qualified" with a `Self`
1994 /// type, if the path points to an associated item in a trait.
1996 /// E.g., an unqualified path like `Clone::clone` has `None` for `Self`,
1997 /// while `<Vec<T> as Clone>::clone` has `Some(Vec<T>)` for `Self`,
1998 /// even though they both have the same two-segment `Clone::clone` `Path`.
1999 Resolved(Option<&'hir Ty<'hir>>, &'hir Path<'hir>),
2001 /// Type-related paths (e.g., `<T>::default` or `<T>::Output`).
2002 /// Will be resolved by type-checking to an associated item.
2004 /// UFCS source paths can desugar into this, with `Vec::new` turning into
2005 /// `<Vec>::new`, and `T::X::Y::method` into `<<<T>::X>::Y>::method`,
2006 /// the `X` and `Y` nodes each being a `TyKind::Path(QPath::TypeRelative(..))`.
2007 TypeRelative(&'hir Ty<'hir>, &'hir PathSegment<'hir>),
2009 /// Reference to a `#[lang = "foo"]` item. `HirId` of the inner expr.
2010 LangItem(LangItem, Span, Option<HirId>),
2013 impl<'hir> QPath<'hir> {
2014 /// Returns the span of this `QPath`.
2015 pub fn span(&self) -> Span {
2017 QPath::Resolved(_, path) => path.span,
2018 QPath::TypeRelative(qself, ps) => qself.span.to(ps.ident.span),
2019 QPath::LangItem(_, span, _) => span,
2023 /// Returns the span of the qself of this `QPath`. For example, `()` in
2024 /// `<() as Trait>::method`.
2025 pub fn qself_span(&self) -> Span {
2027 QPath::Resolved(_, path) => path.span,
2028 QPath::TypeRelative(qself, _) => qself.span,
2029 QPath::LangItem(_, span, _) => span,
2033 /// Returns the span of the last segment of this `QPath`. For example, `method` in
2034 /// `<() as Trait>::method`.
2035 pub fn last_segment_span(&self) -> Span {
2037 QPath::Resolved(_, path) => path.segments.last().unwrap().ident.span,
2038 QPath::TypeRelative(_, segment) => segment.ident.span,
2039 QPath::LangItem(_, span, _) => span,
2044 /// Hints at the original code for a let statement.
2045 #[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)]
2046 pub enum LocalSource {
2047 /// A `match _ { .. }`.
2049 /// When lowering async functions, we create locals within the `async move` so that
2050 /// all parameters are dropped after the future is polled.
2052 /// ```ignore (pseudo-Rust)
2053 /// async fn foo(<pattern> @ x: Type) {
2055 /// let <pattern> = x;
2060 /// A desugared `<expr>.await`.
2062 /// A desugared `expr = expr`, where the LHS is a tuple, struct or array.
2063 /// The span is that of the `=` sign.
2064 AssignDesugar(Span),
2067 /// Hints at the original code for a `match _ { .. }`.
2068 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Hash, Debug)]
2069 #[derive(HashStable_Generic)]
2070 pub enum MatchSource {
2071 /// A `match _ { .. }`.
2073 /// A desugared `for _ in _ { .. }` loop.
2075 /// A desugared `?` operator.
2077 /// A desugared `<expr>.await`.
2083 pub const fn name(self) -> &'static str {
2087 ForLoopDesugar => "for",
2089 AwaitDesugar => ".await",
2094 /// The loop type that yielded an `ExprKind::Loop`.
2095 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
2096 pub enum LoopSource {
2097 /// A `loop { .. }` loop.
2099 /// A `while _ { .. }` loop.
2101 /// A `for _ in _ { .. }` loop.
2106 pub fn name(self) -> &'static str {
2108 LoopSource::Loop => "loop",
2109 LoopSource::While => "while",
2110 LoopSource::ForLoop => "for",
2115 #[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)]
2116 pub enum LoopIdError {
2118 UnlabeledCfInWhileCondition,
2122 impl fmt::Display for LoopIdError {
2123 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2124 f.write_str(match self {
2125 LoopIdError::OutsideLoopScope => "not inside loop scope",
2126 LoopIdError::UnlabeledCfInWhileCondition => {
2127 "unlabeled control flow (break or continue) in while condition"
2129 LoopIdError::UnresolvedLabel => "label not found",
2134 #[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)]
2135 pub struct Destination {
2136 // This is `Some(_)` iff there is an explicit user-specified `label
2137 pub label: Option<Label>,
2139 // These errors are caught and then reported during the diagnostics pass in
2140 // librustc_passes/loops.rs
2141 pub target_id: Result<HirId, LoopIdError>,
2144 /// The yield kind that caused an `ExprKind::Yield`.
2145 #[derive(Copy, Clone, PartialEq, Eq, Debug, Encodable, Decodable, HashStable_Generic)]
2146 pub enum YieldSource {
2147 /// An `<expr>.await`.
2148 Await { expr: Option<HirId> },
2149 /// A plain `yield`.
2154 pub fn is_await(&self) -> bool {
2155 matches!(self, YieldSource::Await { .. })
2159 impl fmt::Display for YieldSource {
2160 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2161 f.write_str(match self {
2162 YieldSource::Await { .. } => "`await`",
2163 YieldSource::Yield => "`yield`",
2168 impl From<GeneratorKind> for YieldSource {
2169 fn from(kind: GeneratorKind) -> Self {
2171 // Guess based on the kind of the current generator.
2172 GeneratorKind::Gen => Self::Yield,
2173 GeneratorKind::Async(_) => Self::Await { expr: None },
2178 // N.B., if you change this, you'll probably want to change the corresponding
2179 // type structure in middle/ty.rs as well.
2180 #[derive(Debug, HashStable_Generic)]
2181 pub struct MutTy<'hir> {
2182 pub ty: &'hir Ty<'hir>,
2183 pub mutbl: Mutability,
2186 /// Represents a function's signature in a trait declaration,
2187 /// trait implementation, or a free function.
2188 #[derive(Debug, HashStable_Generic)]
2189 pub struct FnSig<'hir> {
2190 pub header: FnHeader,
2191 pub decl: &'hir FnDecl<'hir>,
2195 // The bodies for items are stored "out of line", in a separate
2196 // hashmap in the `Crate`. Here we just record the hir-id of the item
2197 // so it can fetched later.
2198 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
2199 pub struct TraitItemId {
2200 pub def_id: LocalDefId,
2205 pub fn hir_id(&self) -> HirId {
2206 // Items are always HIR owners.
2207 HirId::make_owner(self.def_id)
2211 /// Represents an item declaration within a trait declaration,
2212 /// possibly including a default implementation. A trait item is
2213 /// either required (meaning it doesn't have an implementation, just a
2214 /// signature) or provided (meaning it has a default implementation).
2215 #[derive(Debug, HashStable_Generic)]
2216 pub struct TraitItem<'hir> {
2218 pub def_id: LocalDefId,
2219 pub generics: &'hir Generics<'hir>,
2220 pub kind: TraitItemKind<'hir>,
2224 impl TraitItem<'_> {
2226 pub fn hir_id(&self) -> HirId {
2227 // Items are always HIR owners.
2228 HirId::make_owner(self.def_id)
2231 pub fn trait_item_id(&self) -> TraitItemId {
2232 TraitItemId { def_id: self.def_id }
2236 /// Represents a trait method's body (or just argument names).
2237 #[derive(Encodable, Debug, HashStable_Generic)]
2238 pub enum TraitFn<'hir> {
2239 /// No default body in the trait, just a signature.
2240 Required(&'hir [Ident]),
2242 /// Both signature and body are provided in the trait.
2246 /// Represents a trait method or associated constant or type
2247 #[derive(Debug, HashStable_Generic)]
2248 pub enum TraitItemKind<'hir> {
2249 /// An associated constant with an optional value (otherwise `impl`s must contain a value).
2250 Const(&'hir Ty<'hir>, Option<BodyId>),
2251 /// An associated function with an optional body.
2252 Fn(FnSig<'hir>, TraitFn<'hir>),
2253 /// An associated type with (possibly empty) bounds and optional concrete
2255 Type(GenericBounds<'hir>, Option<&'hir Ty<'hir>>),
2258 // The bodies for items are stored "out of line", in a separate
2259 // hashmap in the `Crate`. Here we just record the hir-id of the item
2260 // so it can fetched later.
2261 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
2262 pub struct ImplItemId {
2263 pub def_id: LocalDefId,
2268 pub fn hir_id(&self) -> HirId {
2269 // Items are always HIR owners.
2270 HirId::make_owner(self.def_id)
2274 /// Represents anything within an `impl` block.
2275 #[derive(Debug, HashStable_Generic)]
2276 pub struct ImplItem<'hir> {
2278 pub def_id: LocalDefId,
2279 pub generics: &'hir Generics<'hir>,
2280 pub kind: ImplItemKind<'hir>,
2287 pub fn hir_id(&self) -> HirId {
2288 // Items are always HIR owners.
2289 HirId::make_owner(self.def_id)
2292 pub fn impl_item_id(&self) -> ImplItemId {
2293 ImplItemId { def_id: self.def_id }
2297 /// Represents various kinds of content within an `impl`.
2298 #[derive(Debug, HashStable_Generic)]
2299 pub enum ImplItemKind<'hir> {
2300 /// An associated constant of the given type, set to the constant result
2301 /// of the expression.
2302 Const(&'hir Ty<'hir>, BodyId),
2303 /// An associated function implementation with the given signature and body.
2304 Fn(FnSig<'hir>, BodyId),
2305 /// An associated type.
2306 TyAlias(&'hir Ty<'hir>),
2309 // The name of the associated type for `Fn` return types.
2310 pub const FN_OUTPUT_NAME: Symbol = sym::Output;
2312 /// Bind a type to an associated type (i.e., `A = Foo`).
2314 /// Bindings like `A: Debug` are represented as a special type `A =
2315 /// $::Debug` that is understood by the astconv code.
2317 /// FIXME(alexreg): why have a separate type for the binding case,
2318 /// wouldn't it be better to make the `ty` field an enum like the
2321 /// ```ignore (pseudo-rust)
2322 /// enum TypeBindingKind {
2327 #[derive(Debug, HashStable_Generic)]
2328 pub struct TypeBinding<'hir> {
2331 pub gen_args: &'hir GenericArgs<'hir>,
2332 pub kind: TypeBindingKind<'hir>,
2336 #[derive(Debug, HashStable_Generic)]
2337 pub enum Term<'hir> {
2342 impl<'hir> From<&'hir Ty<'hir>> for Term<'hir> {
2343 fn from(ty: &'hir Ty<'hir>) -> Self {
2348 impl<'hir> From<AnonConst> for Term<'hir> {
2349 fn from(c: AnonConst) -> Self {
2354 // Represents the two kinds of type bindings.
2355 #[derive(Debug, HashStable_Generic)]
2356 pub enum TypeBindingKind<'hir> {
2357 /// E.g., `Foo<Bar: Send>`.
2358 Constraint { bounds: &'hir [GenericBound<'hir>] },
2359 /// E.g., `Foo<Bar = ()>`, `Foo<Bar = ()>`
2360 Equality { term: Term<'hir> },
2363 impl TypeBinding<'_> {
2364 pub fn ty(&self) -> &Ty<'_> {
2366 TypeBindingKind::Equality { term: Term::Ty(ref ty) } => ty,
2367 _ => panic!("expected equality type binding for parenthesized generic args"),
2370 pub fn opt_const(&self) -> Option<&'_ AnonConst> {
2372 TypeBindingKind::Equality { term: Term::Const(ref c) } => Some(c),
2379 pub struct Ty<'hir> {
2381 pub kind: TyKind<'hir>,
2385 impl<'hir> Ty<'hir> {
2386 /// Returns `true` if `param_def_id` matches the `bounded_ty` of this predicate.
2387 pub fn as_generic_param(&self) -> Option<(DefId, Ident)> {
2388 let TyKind::Path(QPath::Resolved(None, path)) = self.kind else {
2391 let [segment] = &path.segments else {
2395 Res::Def(DefKind::TyParam, def_id)
2396 | Res::SelfTy { trait_: Some(def_id), alias_to: None } => Some((def_id, segment.ident)),
2402 /// Not represented directly in the AST; referred to by name through a `ty_path`.
2403 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
2404 #[derive(HashStable_Generic)]
2415 /// All of the primitive types
2416 pub const ALL: [Self; 17] = [
2417 // any changes here should also be reflected in `PrimTy::from_name`
2418 Self::Int(IntTy::I8),
2419 Self::Int(IntTy::I16),
2420 Self::Int(IntTy::I32),
2421 Self::Int(IntTy::I64),
2422 Self::Int(IntTy::I128),
2423 Self::Int(IntTy::Isize),
2424 Self::Uint(UintTy::U8),
2425 Self::Uint(UintTy::U16),
2426 Self::Uint(UintTy::U32),
2427 Self::Uint(UintTy::U64),
2428 Self::Uint(UintTy::U128),
2429 Self::Uint(UintTy::Usize),
2430 Self::Float(FloatTy::F32),
2431 Self::Float(FloatTy::F64),
2437 /// Like [`PrimTy::name`], but returns a &str instead of a symbol.
2440 pub fn name_str(self) -> &'static str {
2442 PrimTy::Int(i) => i.name_str(),
2443 PrimTy::Uint(u) => u.name_str(),
2444 PrimTy::Float(f) => f.name_str(),
2445 PrimTy::Str => "str",
2446 PrimTy::Bool => "bool",
2447 PrimTy::Char => "char",
2451 pub fn name(self) -> Symbol {
2453 PrimTy::Int(i) => i.name(),
2454 PrimTy::Uint(u) => u.name(),
2455 PrimTy::Float(f) => f.name(),
2456 PrimTy::Str => sym::str,
2457 PrimTy::Bool => sym::bool,
2458 PrimTy::Char => sym::char,
2462 /// Returns the matching `PrimTy` for a `Symbol` such as "str" or "i32".
2463 /// Returns `None` if no matching type is found.
2464 pub fn from_name(name: Symbol) -> Option<Self> {
2465 let ty = match name {
2466 // any changes here should also be reflected in `PrimTy::ALL`
2467 sym::i8 => Self::Int(IntTy::I8),
2468 sym::i16 => Self::Int(IntTy::I16),
2469 sym::i32 => Self::Int(IntTy::I32),
2470 sym::i64 => Self::Int(IntTy::I64),
2471 sym::i128 => Self::Int(IntTy::I128),
2472 sym::isize => Self::Int(IntTy::Isize),
2473 sym::u8 => Self::Uint(UintTy::U8),
2474 sym::u16 => Self::Uint(UintTy::U16),
2475 sym::u32 => Self::Uint(UintTy::U32),
2476 sym::u64 => Self::Uint(UintTy::U64),
2477 sym::u128 => Self::Uint(UintTy::U128),
2478 sym::usize => Self::Uint(UintTy::Usize),
2479 sym::f32 => Self::Float(FloatTy::F32),
2480 sym::f64 => Self::Float(FloatTy::F64),
2481 sym::bool => Self::Bool,
2482 sym::char => Self::Char,
2483 sym::str => Self::Str,
2490 #[derive(Debug, HashStable_Generic)]
2491 pub struct BareFnTy<'hir> {
2492 pub unsafety: Unsafety,
2494 pub generic_params: &'hir [GenericParam<'hir>],
2495 pub decl: &'hir FnDecl<'hir>,
2496 pub param_names: &'hir [Ident],
2499 #[derive(Debug, HashStable_Generic)]
2500 pub struct OpaqueTy<'hir> {
2501 pub generics: &'hir Generics<'hir>,
2502 pub bounds: GenericBounds<'hir>,
2503 pub origin: OpaqueTyOrigin,
2506 /// From whence the opaque type came.
2507 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
2508 pub enum OpaqueTyOrigin {
2510 FnReturn(LocalDefId),
2512 AsyncFn(LocalDefId),
2513 /// type aliases: `type Foo = impl Trait;`
2517 /// The various kinds of types recognized by the compiler.
2518 #[derive(Debug, HashStable_Generic)]
2519 pub enum TyKind<'hir> {
2520 /// A variable length slice (i.e., `[T]`).
2521 Slice(&'hir Ty<'hir>),
2522 /// A fixed length array (i.e., `[T; n]`).
2523 Array(&'hir Ty<'hir>, ArrayLen),
2524 /// A raw pointer (i.e., `*const T` or `*mut T`).
2526 /// A reference (i.e., `&'a T` or `&'a mut T`).
2527 Rptr(Lifetime, MutTy<'hir>),
2528 /// A bare function (e.g., `fn(usize) -> bool`).
2529 BareFn(&'hir BareFnTy<'hir>),
2530 /// The never type (`!`).
2532 /// A tuple (`(A, B, C, D, ...)`).
2533 Tup(&'hir [Ty<'hir>]),
2534 /// A path to a type definition (`module::module::...::Type`), or an
2535 /// associated type (e.g., `<Vec<T> as Trait>::Type` or `<T>::Target`).
2537 /// Type parameters may be stored in each `PathSegment`.
2539 /// An opaque type definition itself. This is only used for `impl Trait`.
2541 /// The generic argument list contains the lifetimes (and in the future
2542 /// possibly parameters) that are actually bound on the `impl Trait`.
2543 OpaqueDef(ItemId, &'hir [GenericArg<'hir>]),
2544 /// A trait object type `Bound1 + Bound2 + Bound3`
2545 /// where `Bound` is a trait or a lifetime.
2546 TraitObject(&'hir [PolyTraitRef<'hir>], Lifetime, TraitObjectSyntax),
2549 /// `TyKind::Infer` means the type should be inferred instead of it having been
2550 /// specified. This can appear anywhere in a type.
2552 /// Placeholder for a type that has failed to be defined.
2556 #[derive(Debug, HashStable_Generic)]
2557 pub enum InlineAsmOperand<'hir> {
2559 reg: InlineAsmRegOrRegClass,
2563 reg: InlineAsmRegOrRegClass,
2565 expr: Option<Expr<'hir>>,
2568 reg: InlineAsmRegOrRegClass,
2573 reg: InlineAsmRegOrRegClass,
2575 in_expr: Expr<'hir>,
2576 out_expr: Option<Expr<'hir>>,
2579 anon_const: AnonConst,
2582 anon_const: AnonConst,
2590 impl<'hir> InlineAsmOperand<'hir> {
2591 pub fn reg(&self) -> Option<InlineAsmRegOrRegClass> {
2593 Self::In { reg, .. }
2594 | Self::Out { reg, .. }
2595 | Self::InOut { reg, .. }
2596 | Self::SplitInOut { reg, .. } => Some(reg),
2597 Self::Const { .. } | Self::SymFn { .. } | Self::SymStatic { .. } => None,
2601 pub fn is_clobber(&self) -> bool {
2604 InlineAsmOperand::Out { reg: InlineAsmRegOrRegClass::Reg(_), late: _, expr: None }
2609 #[derive(Debug, HashStable_Generic)]
2610 pub struct InlineAsm<'hir> {
2611 pub template: &'hir [InlineAsmTemplatePiece],
2612 pub template_strs: &'hir [(Symbol, Option<Symbol>, Span)],
2613 pub operands: &'hir [(InlineAsmOperand<'hir>, Span)],
2614 pub options: InlineAsmOptions,
2615 pub line_spans: &'hir [Span],
2618 /// Represents a parameter in a function header.
2619 #[derive(Debug, HashStable_Generic)]
2620 pub struct Param<'hir> {
2622 pub pat: &'hir Pat<'hir>,
2627 /// Represents the header (not the body) of a function declaration.
2628 #[derive(Debug, HashStable_Generic)]
2629 pub struct FnDecl<'hir> {
2630 /// The types of the function's parameters.
2632 /// Additional argument data is stored in the function's [body](Body::params).
2633 pub inputs: &'hir [Ty<'hir>],
2634 pub output: FnRetTy<'hir>,
2635 pub c_variadic: bool,
2636 /// Does the function have an implicit self?
2637 pub implicit_self: ImplicitSelfKind,
2640 /// Represents what type of implicit self a function has, if any.
2641 #[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2642 pub enum ImplicitSelfKind {
2643 /// Represents a `fn x(self);`.
2645 /// Represents a `fn x(mut self);`.
2647 /// Represents a `fn x(&self);`.
2649 /// Represents a `fn x(&mut self);`.
2651 /// Represents when a function does not have a self argument or
2652 /// when a function has a `self: X` argument.
2656 impl ImplicitSelfKind {
2657 /// Does this represent an implicit self?
2658 pub fn has_implicit_self(&self) -> bool {
2659 !matches!(*self, ImplicitSelfKind::None)
2663 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Encodable, Decodable, Debug)]
2664 #[derive(HashStable_Generic)]
2670 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Encodable, Decodable, HashStable_Generic)]
2671 pub enum Defaultness {
2672 Default { has_value: bool },
2677 pub fn has_value(&self) -> bool {
2679 Defaultness::Default { has_value } => has_value,
2680 Defaultness::Final => true,
2684 pub fn is_final(&self) -> bool {
2685 *self == Defaultness::Final
2688 pub fn is_default(&self) -> bool {
2689 matches!(*self, Defaultness::Default { .. })
2693 #[derive(Debug, HashStable_Generic)]
2694 pub enum FnRetTy<'hir> {
2695 /// Return type is not specified.
2697 /// Functions default to `()` and
2698 /// closures default to inference. Span points to where return
2699 /// type would be inserted.
2700 DefaultReturn(Span),
2701 /// Everything else.
2702 Return(&'hir Ty<'hir>),
2707 pub fn span(&self) -> Span {
2709 Self::DefaultReturn(span) => span,
2710 Self::Return(ref ty) => ty.span,
2715 /// Represents `for<...>` binder before a closure
2716 #[derive(Copy, Clone, Debug, HashStable_Generic)]
2717 pub enum ClosureBinder {
2718 /// Binder is not specified.
2720 /// Binder is specified.
2722 /// Span points to the whole `for<...>`.
2726 #[derive(Encodable, Debug, HashStable_Generic)]
2727 pub struct Mod<'hir> {
2728 pub spans: ModSpans,
2729 pub item_ids: &'hir [ItemId],
2732 #[derive(Copy, Clone, Debug, HashStable_Generic, Encodable)]
2733 pub struct ModSpans {
2734 /// A span from the first token past `{` to the last token until `}`.
2735 /// For `mod foo;`, the inner span ranges from the first token
2736 /// to the last token in the external file.
2737 pub inner_span: Span,
2738 pub inject_use_span: Span,
2741 #[derive(Debug, HashStable_Generic)]
2742 pub struct EnumDef<'hir> {
2743 pub variants: &'hir [Variant<'hir>],
2746 #[derive(Debug, HashStable_Generic)]
2747 pub struct Variant<'hir> {
2748 /// Name of the variant.
2750 /// Id of the variant (not the constructor, see `VariantData::ctor_hir_id()`).
2752 /// Fields and constructor id of the variant.
2753 pub data: VariantData<'hir>,
2754 /// Explicit discriminant (e.g., `Foo = 1`).
2755 pub disr_expr: Option<AnonConst>,
2760 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
2762 /// One import, e.g., `use foo::bar` or `use foo::bar as baz`.
2763 /// Also produced for each element of a list `use`, e.g.
2764 /// `use foo::{a, b}` lowers to `use foo::a; use foo::b;`.
2767 /// Glob import, e.g., `use foo::*`.
2770 /// Degenerate list import, e.g., `use foo::{a, b}` produces
2771 /// an additional `use foo::{}` for performing checks such as
2772 /// unstable feature gating. May be removed in the future.
2776 /// References to traits in impls.
2778 /// `resolve` maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2779 /// that the `ref_id` is for. Note that `ref_id`'s value is not the `HirId` of the
2780 /// trait being referred to but just a unique `HirId` that serves as a key
2781 /// within the resolution map.
2782 #[derive(Clone, Debug, HashStable_Generic)]
2783 pub struct TraitRef<'hir> {
2784 pub path: &'hir Path<'hir>,
2785 // Don't hash the `ref_id`. It is tracked via the thing it is used to access.
2786 #[stable_hasher(ignore)]
2787 pub hir_ref_id: HirId,
2791 /// Gets the `DefId` of the referenced trait. It _must_ actually be a trait or trait alias.
2792 pub fn trait_def_id(&self) -> Option<DefId> {
2793 match self.path.res {
2794 Res::Def(DefKind::Trait | DefKind::TraitAlias, did) => Some(did),
2796 _ => unreachable!(),
2801 #[derive(Clone, Debug, HashStable_Generic)]
2802 pub struct PolyTraitRef<'hir> {
2803 /// The `'a` in `for<'a> Foo<&'a T>`.
2804 pub bound_generic_params: &'hir [GenericParam<'hir>],
2806 /// The `Foo<&'a T>` in `for<'a> Foo<&'a T>`.
2807 pub trait_ref: TraitRef<'hir>,
2812 #[derive(Debug, HashStable_Generic)]
2813 pub struct FieldDef<'hir> {
2818 pub ty: &'hir Ty<'hir>,
2822 // Still necessary in couple of places
2823 pub fn is_positional(&self) -> bool {
2824 let first = self.ident.as_str().as_bytes()[0];
2825 (b'0'..=b'9').contains(&first)
2829 /// Fields and constructor IDs of enum variants and structs.
2830 #[derive(Debug, HashStable_Generic)]
2831 pub enum VariantData<'hir> {
2832 /// A struct variant.
2834 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2835 Struct(&'hir [FieldDef<'hir>], /* recovered */ bool),
2836 /// A tuple variant.
2838 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2839 Tuple(&'hir [FieldDef<'hir>], HirId),
2842 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2846 impl<'hir> VariantData<'hir> {
2847 /// Return the fields of this variant.
2848 pub fn fields(&self) -> &'hir [FieldDef<'hir>] {
2850 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, ..) => fields,
2855 /// Return the `HirId` of this variant's constructor, if it has one.
2856 pub fn ctor_hir_id(&self) -> Option<HirId> {
2858 VariantData::Struct(_, _) => None,
2859 VariantData::Tuple(_, hir_id) | VariantData::Unit(hir_id) => Some(hir_id),
2864 // The bodies for items are stored "out of line", in a separate
2865 // hashmap in the `Crate`. Here we just record the hir-id of the item
2866 // so it can fetched later.
2867 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
2869 pub def_id: LocalDefId,
2874 pub fn hir_id(&self) -> HirId {
2875 // Items are always HIR owners.
2876 HirId::make_owner(self.def_id)
2882 /// The name might be a dummy name in case of anonymous items
2883 #[derive(Debug, HashStable_Generic)]
2884 pub struct Item<'hir> {
2886 pub def_id: LocalDefId,
2887 pub kind: ItemKind<'hir>,
2894 pub fn hir_id(&self) -> HirId {
2895 // Items are always HIR owners.
2896 HirId::make_owner(self.def_id)
2899 pub fn item_id(&self) -> ItemId {
2900 ItemId { def_id: self.def_id }
2904 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
2905 #[derive(Encodable, Decodable, HashStable_Generic)]
2912 pub fn prefix_str(&self) -> &'static str {
2914 Self::Unsafe => "unsafe ",
2920 impl fmt::Display for Unsafety {
2921 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2922 f.write_str(match *self {
2923 Self::Unsafe => "unsafe",
2924 Self::Normal => "normal",
2929 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
2930 #[derive(Encodable, Decodable, HashStable_Generic)]
2931 pub enum Constness {
2936 impl fmt::Display for Constness {
2937 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2938 f.write_str(match *self {
2939 Self::Const => "const",
2940 Self::NotConst => "non-const",
2945 #[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)]
2946 pub struct FnHeader {
2947 pub unsafety: Unsafety,
2948 pub constness: Constness,
2949 pub asyncness: IsAsync,
2954 pub fn is_async(&self) -> bool {
2955 matches!(&self.asyncness, IsAsync::Async)
2958 pub fn is_const(&self) -> bool {
2959 matches!(&self.constness, Constness::Const)
2962 pub fn is_unsafe(&self) -> bool {
2963 matches!(&self.unsafety, Unsafety::Unsafe)
2967 #[derive(Debug, HashStable_Generic)]
2968 pub enum ItemKind<'hir> {
2969 /// An `extern crate` item, with optional *original* crate name if the crate was renamed.
2971 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2972 ExternCrate(Option<Symbol>),
2974 /// `use foo::bar::*;` or `use foo::bar::baz as quux;`
2978 /// `use foo::bar::baz;` (with `as baz` implicitly on the right).
2979 Use(&'hir Path<'hir>, UseKind),
2981 /// A `static` item.
2982 Static(&'hir Ty<'hir>, Mutability, BodyId),
2984 Const(&'hir Ty<'hir>, BodyId),
2985 /// A function declaration.
2986 Fn(FnSig<'hir>, &'hir Generics<'hir>, BodyId),
2987 /// A MBE macro definition (`macro_rules!` or `macro`).
2988 Macro(ast::MacroDef, MacroKind),
2991 /// An external module, e.g. `extern { .. }`.
2992 ForeignMod { abi: Abi, items: &'hir [ForeignItemRef] },
2993 /// Module-level inline assembly (from `global_asm!`).
2994 GlobalAsm(&'hir InlineAsm<'hir>),
2995 /// A type alias, e.g., `type Foo = Bar<u8>`.
2996 TyAlias(&'hir Ty<'hir>, &'hir Generics<'hir>),
2997 /// An opaque `impl Trait` type alias, e.g., `type Foo = impl Bar;`.
2998 OpaqueTy(OpaqueTy<'hir>),
2999 /// An enum definition, e.g., `enum Foo<A, B> {C<A>, D<B>}`.
3000 Enum(EnumDef<'hir>, &'hir Generics<'hir>),
3001 /// A struct definition, e.g., `struct Foo<A> {x: A}`.
3002 Struct(VariantData<'hir>, &'hir Generics<'hir>),
3003 /// A union definition, e.g., `union Foo<A, B> {x: A, y: B}`.
3004 Union(VariantData<'hir>, &'hir Generics<'hir>),
3005 /// A trait definition.
3006 Trait(IsAuto, Unsafety, &'hir Generics<'hir>, GenericBounds<'hir>, &'hir [TraitItemRef]),
3008 TraitAlias(&'hir Generics<'hir>, GenericBounds<'hir>),
3010 /// An implementation, e.g., `impl<A> Trait for Foo { .. }`.
3011 Impl(&'hir Impl<'hir>),
3014 #[derive(Debug, HashStable_Generic)]
3015 pub struct Impl<'hir> {
3016 pub unsafety: Unsafety,
3017 pub polarity: ImplPolarity,
3018 pub defaultness: Defaultness,
3019 // We do not put a `Span` in `Defaultness` because it breaks foreign crate metadata
3020 // decoding as `Span`s cannot be decoded when a `Session` is not available.
3021 pub defaultness_span: Option<Span>,
3022 pub constness: Constness,
3023 pub generics: &'hir Generics<'hir>,
3025 /// The trait being implemented, if any.
3026 pub of_trait: Option<TraitRef<'hir>>,
3028 pub self_ty: &'hir Ty<'hir>,
3029 pub items: &'hir [ImplItemRef],
3033 pub fn generics(&self) -> Option<&Generics<'_>> {
3035 ItemKind::Fn(_, ref generics, _)
3036 | ItemKind::TyAlias(_, ref generics)
3037 | ItemKind::OpaqueTy(OpaqueTy { ref generics, .. })
3038 | ItemKind::Enum(_, ref generics)
3039 | ItemKind::Struct(_, ref generics)
3040 | ItemKind::Union(_, ref generics)
3041 | ItemKind::Trait(_, _, ref generics, _, _)
3042 | ItemKind::TraitAlias(ref generics, _)
3043 | ItemKind::Impl(Impl { ref generics, .. }) => generics,
3048 pub fn descr(&self) -> &'static str {
3050 ItemKind::ExternCrate(..) => "extern crate",
3051 ItemKind::Use(..) => "`use` import",
3052 ItemKind::Static(..) => "static item",
3053 ItemKind::Const(..) => "constant item",
3054 ItemKind::Fn(..) => "function",
3055 ItemKind::Macro(..) => "macro",
3056 ItemKind::Mod(..) => "module",
3057 ItemKind::ForeignMod { .. } => "extern block",
3058 ItemKind::GlobalAsm(..) => "global asm item",
3059 ItemKind::TyAlias(..) => "type alias",
3060 ItemKind::OpaqueTy(..) => "opaque type",
3061 ItemKind::Enum(..) => "enum",
3062 ItemKind::Struct(..) => "struct",
3063 ItemKind::Union(..) => "union",
3064 ItemKind::Trait(..) => "trait",
3065 ItemKind::TraitAlias(..) => "trait alias",
3066 ItemKind::Impl(..) => "implementation",
3071 /// A reference from an trait to one of its associated items. This
3072 /// contains the item's id, naturally, but also the item's name and
3073 /// some other high-level details (like whether it is an associated
3074 /// type or method, and whether it is public). This allows other
3075 /// passes to find the impl they want without loading the ID (which
3076 /// means fewer edges in the incremental compilation graph).
3077 #[derive(Encodable, Debug, HashStable_Generic)]
3078 pub struct TraitItemRef {
3079 pub id: TraitItemId,
3081 pub kind: AssocItemKind,
3083 pub defaultness: Defaultness,
3086 /// A reference from an impl to one of its associated items. This
3087 /// contains the item's ID, naturally, but also the item's name and
3088 /// some other high-level details (like whether it is an associated
3089 /// type or method, and whether it is public). This allows other
3090 /// passes to find the impl they want without loading the ID (which
3091 /// means fewer edges in the incremental compilation graph).
3092 #[derive(Debug, HashStable_Generic)]
3093 pub struct ImplItemRef {
3096 pub kind: AssocItemKind,
3098 pub defaultness: Defaultness,
3099 /// When we are in a trait impl, link to the trait-item's id.
3100 pub trait_item_def_id: Option<DefId>,
3103 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
3104 pub enum AssocItemKind {
3106 Fn { has_self: bool },
3110 // The bodies for items are stored "out of line", in a separate
3111 // hashmap in the `Crate`. Here we just record the hir-id of the item
3112 // so it can fetched later.
3113 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
3114 pub struct ForeignItemId {
3115 pub def_id: LocalDefId,
3118 impl ForeignItemId {
3120 pub fn hir_id(&self) -> HirId {
3121 // Items are always HIR owners.
3122 HirId::make_owner(self.def_id)
3126 /// A reference from a foreign block to one of its items. This
3127 /// contains the item's ID, naturally, but also the item's name and
3128 /// some other high-level details (like whether it is an associated
3129 /// type or method, and whether it is public). This allows other
3130 /// passes to find the impl they want without loading the ID (which
3131 /// means fewer edges in the incremental compilation graph).
3132 #[derive(Debug, HashStable_Generic)]
3133 pub struct ForeignItemRef {
3134 pub id: ForeignItemId,
3139 #[derive(Debug, HashStable_Generic)]
3140 pub struct ForeignItem<'hir> {
3142 pub kind: ForeignItemKind<'hir>,
3143 pub def_id: LocalDefId,
3148 impl ForeignItem<'_> {
3150 pub fn hir_id(&self) -> HirId {
3151 // Items are always HIR owners.
3152 HirId::make_owner(self.def_id)
3155 pub fn foreign_item_id(&self) -> ForeignItemId {
3156 ForeignItemId { def_id: self.def_id }
3160 /// An item within an `extern` block.
3161 #[derive(Debug, HashStable_Generic)]
3162 pub enum ForeignItemKind<'hir> {
3163 /// A foreign function.
3164 Fn(&'hir FnDecl<'hir>, &'hir [Ident], &'hir Generics<'hir>),
3165 /// A foreign static item (`static ext: u8`).
3166 Static(&'hir Ty<'hir>, Mutability),
3171 /// A variable captured by a closure.
3172 #[derive(Debug, Copy, Clone, Encodable, HashStable_Generic)]
3174 // First span where it is accessed (there can be multiple).
3178 // The TraitCandidate's import_ids is empty if the trait is defined in the same module, and
3179 // has length > 0 if the trait is found through an chain of imports, starting with the
3180 // import/use statement in the scope where the trait is used.
3181 #[derive(Encodable, Decodable, Clone, Debug, HashStable_Generic)]
3182 pub struct TraitCandidate {
3184 pub import_ids: SmallVec<[LocalDefId; 1]>,
3187 #[derive(Copy, Clone, Debug, HashStable_Generic)]
3188 pub enum OwnerNode<'hir> {
3189 Item(&'hir Item<'hir>),
3190 ForeignItem(&'hir ForeignItem<'hir>),
3191 TraitItem(&'hir TraitItem<'hir>),
3192 ImplItem(&'hir ImplItem<'hir>),
3193 Crate(&'hir Mod<'hir>),
3196 impl<'hir> OwnerNode<'hir> {
3197 pub fn ident(&self) -> Option<Ident> {
3199 OwnerNode::Item(Item { ident, .. })
3200 | OwnerNode::ForeignItem(ForeignItem { ident, .. })
3201 | OwnerNode::ImplItem(ImplItem { ident, .. })
3202 | OwnerNode::TraitItem(TraitItem { ident, .. }) => Some(*ident),
3203 OwnerNode::Crate(..) => None,
3207 pub fn span(&self) -> Span {
3209 OwnerNode::Item(Item { span, .. })
3210 | OwnerNode::ForeignItem(ForeignItem { span, .. })
3211 | OwnerNode::ImplItem(ImplItem { span, .. })
3212 | OwnerNode::TraitItem(TraitItem { span, .. }) => *span,
3213 OwnerNode::Crate(Mod { spans: ModSpans { inner_span, .. }, .. }) => *inner_span,
3217 pub fn fn_decl(&self) -> Option<&FnDecl<'hir>> {
3219 OwnerNode::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
3220 | OwnerNode::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
3221 | OwnerNode::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig.decl),
3222 OwnerNode::ForeignItem(ForeignItem {
3223 kind: ForeignItemKind::Fn(fn_decl, _, _),
3225 }) => Some(fn_decl),
3230 pub fn body_id(&self) -> Option<BodyId> {
3232 OwnerNode::TraitItem(TraitItem {
3233 kind: TraitItemKind::Fn(_, TraitFn::Provided(body_id)),
3236 | OwnerNode::ImplItem(ImplItem { kind: ImplItemKind::Fn(_, body_id), .. })
3237 | OwnerNode::Item(Item { kind: ItemKind::Fn(.., body_id), .. }) => Some(*body_id),
3242 pub fn generics(self) -> Option<&'hir Generics<'hir>> {
3243 Node::generics(self.into())
3246 pub fn def_id(self) -> LocalDefId {
3248 OwnerNode::Item(Item { def_id, .. })
3249 | OwnerNode::TraitItem(TraitItem { def_id, .. })
3250 | OwnerNode::ImplItem(ImplItem { def_id, .. })
3251 | OwnerNode::ForeignItem(ForeignItem { def_id, .. }) => *def_id,
3252 OwnerNode::Crate(..) => crate::CRATE_HIR_ID.owner,
3256 pub fn expect_item(self) -> &'hir Item<'hir> {
3258 OwnerNode::Item(n) => n,
3263 pub fn expect_foreign_item(self) -> &'hir ForeignItem<'hir> {
3265 OwnerNode::ForeignItem(n) => n,
3270 pub fn expect_impl_item(self) -> &'hir ImplItem<'hir> {
3272 OwnerNode::ImplItem(n) => n,
3277 pub fn expect_trait_item(self) -> &'hir TraitItem<'hir> {
3279 OwnerNode::TraitItem(n) => n,
3285 impl<'hir> Into<OwnerNode<'hir>> for &'hir Item<'hir> {
3286 fn into(self) -> OwnerNode<'hir> {
3287 OwnerNode::Item(self)
3291 impl<'hir> Into<OwnerNode<'hir>> for &'hir ForeignItem<'hir> {
3292 fn into(self) -> OwnerNode<'hir> {
3293 OwnerNode::ForeignItem(self)
3297 impl<'hir> Into<OwnerNode<'hir>> for &'hir ImplItem<'hir> {
3298 fn into(self) -> OwnerNode<'hir> {
3299 OwnerNode::ImplItem(self)
3303 impl<'hir> Into<OwnerNode<'hir>> for &'hir TraitItem<'hir> {
3304 fn into(self) -> OwnerNode<'hir> {
3305 OwnerNode::TraitItem(self)
3309 impl<'hir> Into<Node<'hir>> for OwnerNode<'hir> {
3310 fn into(self) -> Node<'hir> {
3312 OwnerNode::Item(n) => Node::Item(n),
3313 OwnerNode::ForeignItem(n) => Node::ForeignItem(n),
3314 OwnerNode::ImplItem(n) => Node::ImplItem(n),
3315 OwnerNode::TraitItem(n) => Node::TraitItem(n),
3316 OwnerNode::Crate(n) => Node::Crate(n),
3321 #[derive(Copy, Clone, Debug, HashStable_Generic)]
3322 pub enum Node<'hir> {
3323 Param(&'hir Param<'hir>),
3324 Item(&'hir Item<'hir>),
3325 ForeignItem(&'hir ForeignItem<'hir>),
3326 TraitItem(&'hir TraitItem<'hir>),
3327 ImplItem(&'hir ImplItem<'hir>),
3328 Variant(&'hir Variant<'hir>),
3329 Field(&'hir FieldDef<'hir>),
3330 AnonConst(&'hir AnonConst),
3331 Expr(&'hir Expr<'hir>),
3332 Stmt(&'hir Stmt<'hir>),
3333 PathSegment(&'hir PathSegment<'hir>),
3335 TypeBinding(&'hir TypeBinding<'hir>),
3336 TraitRef(&'hir TraitRef<'hir>),
3337 Pat(&'hir Pat<'hir>),
3338 Arm(&'hir Arm<'hir>),
3339 Block(&'hir Block<'hir>),
3340 Local(&'hir Local<'hir>),
3342 /// `Ctor` refers to the constructor of an enum variant or struct. Only tuple or unit variants
3343 /// with synthesized constructors.
3344 Ctor(&'hir VariantData<'hir>),
3346 Lifetime(&'hir Lifetime),
3347 GenericParam(&'hir GenericParam<'hir>),
3349 Crate(&'hir Mod<'hir>),
3351 Infer(&'hir InferArg),
3354 impl<'hir> Node<'hir> {
3355 /// Get the identifier of this `Node`, if applicable.
3359 /// Calling `.ident()` on a [`Node::Ctor`] will return `None`
3360 /// because `Ctor`s do not have identifiers themselves.
3361 /// Instead, call `.ident()` on the parent struct/variant, like so:
3363 /// ```ignore (illustrative)
3366 /// .and_then(|ctor_id| tcx.hir().find(tcx.hir().get_parent_node(ctor_id)))
3367 /// .and_then(|parent| parent.ident())
3369 pub fn ident(&self) -> Option<Ident> {
3371 Node::TraitItem(TraitItem { ident, .. })
3372 | Node::ImplItem(ImplItem { ident, .. })
3373 | Node::ForeignItem(ForeignItem { ident, .. })
3374 | Node::Field(FieldDef { ident, .. })
3375 | Node::Variant(Variant { ident, .. })
3376 | Node::Item(Item { ident, .. })
3377 | Node::PathSegment(PathSegment { ident, .. }) => Some(*ident),
3378 Node::Lifetime(lt) => Some(lt.name.ident()),
3379 Node::GenericParam(p) => Some(p.name.ident()),
3380 Node::TypeBinding(b) => Some(b.ident),
3382 | Node::AnonConst(..)
3392 | Node::TraitRef(..)
3393 | Node::Infer(..) => None,
3397 pub fn fn_decl(&self) -> Option<&'hir FnDecl<'hir>> {
3399 Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
3400 | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
3401 | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig.decl),
3402 Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_decl, _, _), .. }) => {
3409 pub fn fn_sig(&self) -> Option<&'hir FnSig<'hir>> {
3411 Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
3412 | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
3413 | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig),
3418 pub fn body_id(&self) -> Option<BodyId> {
3420 Node::TraitItem(TraitItem {
3421 kind: TraitItemKind::Fn(_, TraitFn::Provided(body_id)),
3424 | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(_, body_id), .. })
3425 | Node::Item(Item { kind: ItemKind::Fn(.., body_id), .. }) => Some(*body_id),
3430 pub fn generics(self) -> Option<&'hir Generics<'hir>> {
3432 Node::ForeignItem(ForeignItem {
3433 kind: ForeignItemKind::Fn(_, _, generics), ..
3435 | Node::TraitItem(TraitItem { generics, .. })
3436 | Node::ImplItem(ImplItem { generics, .. }) => Some(generics),
3437 Node::Item(item) => item.kind.generics(),
3442 pub fn as_owner(self) -> Option<OwnerNode<'hir>> {
3444 Node::Item(i) => Some(OwnerNode::Item(i)),
3445 Node::ForeignItem(i) => Some(OwnerNode::ForeignItem(i)),
3446 Node::TraitItem(i) => Some(OwnerNode::TraitItem(i)),
3447 Node::ImplItem(i) => Some(OwnerNode::ImplItem(i)),
3448 Node::Crate(i) => Some(OwnerNode::Crate(i)),
3453 pub fn fn_kind(self) -> Option<FnKind<'hir>> {
3455 Node::Item(i) => match i.kind {
3456 ItemKind::Fn(ref sig, ref generics, _) => {
3457 Some(FnKind::ItemFn(i.ident, generics, sig.header))
3461 Node::TraitItem(ti) => match ti.kind {
3462 TraitItemKind::Fn(ref sig, TraitFn::Provided(_)) => {
3463 Some(FnKind::Method(ti.ident, sig))
3467 Node::ImplItem(ii) => match ii.kind {
3468 ImplItemKind::Fn(ref sig, _) => Some(FnKind::Method(ii.ident, sig)),
3471 Node::Expr(e) => match e.kind {
3472 ExprKind::Closure { .. } => Some(FnKind::Closure),
3479 /// Get the fields for the tuple-constructor,
3480 /// if this node is a tuple constructor, otherwise None
3481 pub fn tuple_fields(&self) -> Option<&'hir [FieldDef<'hir>]> {
3482 if let Node::Ctor(&VariantData::Tuple(fields, _)) = self { Some(fields) } else { None }
3486 // Some nodes are used a lot. Make sure they don't unintentionally get bigger.
3487 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
3489 rustc_data_structures::static_assert_size!(super::Block<'static>, 48);
3490 rustc_data_structures::static_assert_size!(super::Expr<'static>, 56);
3491 rustc_data_structures::static_assert_size!(super::Pat<'static>, 88);
3492 rustc_data_structures::static_assert_size!(super::QPath<'static>, 24);
3493 rustc_data_structures::static_assert_size!(super::Ty<'static>, 72);
3494 rustc_data_structures::static_assert_size!(super::GenericBound<'_>, 48);
3495 rustc_data_structures::static_assert_size!(super::Generics<'static>, 56);
3496 rustc_data_structures::static_assert_size!(super::Impl<'static>, 80);
3498 rustc_data_structures::static_assert_size!(super::Item<'static>, 80);
3499 rustc_data_structures::static_assert_size!(super::TraitItem<'static>, 88);
3500 rustc_data_structures::static_assert_size!(super::ImplItem<'static>, 80);
3501 rustc_data_structures::static_assert_size!(super::ForeignItem<'static>, 72);