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Diffstat (limited to 'compiler/rustc_hir/src/hir.rs')
| -rw-r--r-- | compiler/rustc_hir/src/hir.rs | 3506 |
1 files changed, 3506 insertions, 0 deletions
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs new file mode 100644 index 000000000..617433a98 --- /dev/null +++ b/compiler/rustc_hir/src/hir.rs @@ -0,0 +1,3506 @@ +use crate::def::{CtorKind, DefKind, Res}; +use crate::def_id::DefId; +pub(crate) use crate::hir_id::{HirId, ItemLocalId}; +use crate::intravisit::FnKind; +use crate::LangItem; + +use rustc_ast as ast; +use rustc_ast::util::parser::ExprPrecedence; +use rustc_ast::{Attribute, FloatTy, IntTy, Label, LitKind, TraitObjectSyntax, UintTy}; +pub use rustc_ast::{BorrowKind, ImplPolarity, IsAuto}; +pub use rustc_ast::{CaptureBy, Movability, Mutability}; +use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece}; +use rustc_data_structures::fingerprint::Fingerprint; +use rustc_data_structures::fx::FxHashMap; +use rustc_data_structures::sorted_map::SortedMap; +use rustc_error_messages::MultiSpan; +use rustc_index::vec::IndexVec; +use rustc_macros::HashStable_Generic; +use rustc_span::hygiene::MacroKind; +use rustc_span::source_map::Spanned; +use rustc_span::symbol::{kw, sym, Ident, Symbol}; +use rustc_span::{def_id::LocalDefId, BytePos, Span, DUMMY_SP}; +use rustc_target::asm::InlineAsmRegOrRegClass; +use rustc_target::spec::abi::Abi; + +use smallvec::SmallVec; +use std::fmt; + +#[derive(Debug, Copy, Clone, Encodable, HashStable_Generic)] +pub struct Lifetime { + pub hir_id: HirId, + pub span: Span, + + /// Either "`'a`", referring to a named lifetime definition, + /// or "``" (i.e., `kw::Empty`), for elision placeholders. + /// + /// HIR lowering inserts these placeholders in type paths that + /// refer to type definitions needing lifetime parameters, + /// `&T` and `&mut T`, and trait objects without `... + 'a`. + pub name: LifetimeName, +} + +#[derive(Debug, Clone, PartialEq, Eq, Encodable, Hash, Copy)] +#[derive(HashStable_Generic)] +pub enum ParamName { + /// Some user-given name like `T` or `'x`. + Plain(Ident), + + /// Synthetic name generated when user elided a lifetime in an impl header. + /// + /// E.g., the lifetimes in cases like these: + /// ```ignore (fragment) + /// impl Foo for &u32 + /// impl Foo<'_> for u32 + /// ``` + /// in that case, we rewrite to + /// ```ignore (fragment) + /// impl<'f> Foo for &'f u32 + /// impl<'f> Foo<'f> for u32 + /// ``` + /// where `'f` is something like `Fresh(0)`. The indices are + /// unique per impl, but not necessarily continuous. + Fresh, + + /// Indicates an illegal name was given and an error has been + /// reported (so we should squelch other derived errors). Occurs + /// when, e.g., `'_` is used in the wrong place. + Error, +} + +impl ParamName { + pub fn ident(&self) -> Ident { + match *self { + ParamName::Plain(ident) => ident, + ParamName::Fresh | ParamName::Error => Ident::with_dummy_span(kw::UnderscoreLifetime), + } + } + + pub fn normalize_to_macros_2_0(&self) -> ParamName { + match *self { + ParamName::Plain(ident) => ParamName::Plain(ident.normalize_to_macros_2_0()), + param_name => param_name, + } + } +} + +#[derive(Debug, Clone, PartialEq, Eq, Encodable, Hash, Copy)] +#[derive(HashStable_Generic)] +pub enum LifetimeName { + /// User-given names or fresh (synthetic) names. + Param(LocalDefId, ParamName), + + /// Implicit lifetime in a context like `dyn Foo`. This is + /// distinguished from implicit lifetimes elsewhere because the + /// lifetime that they default to must appear elsewhere within the + /// enclosing type. This means that, in an `impl Trait` context, we + /// don't have to create a parameter for them. That is, `impl + /// Trait<Item = &u32>` expands to an opaque type like `type + /// Foo<'a> = impl Trait<Item = &'a u32>`, but `impl Trait<item = + /// dyn Bar>` expands to `type Foo = impl Trait<Item = dyn Bar + + /// 'static>`. The latter uses `ImplicitObjectLifetimeDefault` so + /// that surrounding code knows not to create a lifetime + /// parameter. + ImplicitObjectLifetimeDefault, + + /// Indicates an error during lowering (usually `'_` in wrong place) + /// that was already reported. + Error, + + /// User wrote an anonymous lifetime, either `'_` or nothing. + /// The semantics of this lifetime should be inferred by typechecking code. + Infer, + + /// User wrote `'static`. + Static, +} + +impl LifetimeName { + pub fn ident(&self) -> Ident { + match *self { + LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Error => Ident::empty(), + LifetimeName::Infer => Ident::with_dummy_span(kw::UnderscoreLifetime), + LifetimeName::Static => Ident::with_dummy_span(kw::StaticLifetime), + LifetimeName::Param(_, param_name) => param_name.ident(), + } + } + + pub fn is_anonymous(&self) -> bool { + match *self { + LifetimeName::ImplicitObjectLifetimeDefault + | LifetimeName::Infer + | LifetimeName::Param(_, ParamName::Fresh) + | LifetimeName::Error => true, + LifetimeName::Static | LifetimeName::Param(..) => false, + } + } + + pub fn is_elided(&self) -> bool { + match self { + LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Infer => true, + + // It might seem surprising that `Fresh` counts as + // *not* elided -- but this is because, as far as the code + // in the compiler is concerned -- `Fresh` variants act + // equivalently to "some fresh name". They correspond to + // early-bound regions on an impl, in other words. + LifetimeName::Error | LifetimeName::Param(..) | LifetimeName::Static => false, + } + } + + fn is_static(&self) -> bool { + self == &LifetimeName::Static + } + + pub fn normalize_to_macros_2_0(&self) -> LifetimeName { + match *self { + LifetimeName::Param(def_id, param_name) => { + LifetimeName::Param(def_id, param_name.normalize_to_macros_2_0()) + } + lifetime_name => lifetime_name, + } + } +} + +impl fmt::Display for Lifetime { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.name.ident().fmt(f) + } +} + +impl Lifetime { + pub fn is_elided(&self) -> bool { + self.name.is_elided() + } + + pub fn is_static(&self) -> bool { + self.name.is_static() + } +} + +/// A `Path` is essentially Rust's notion of a name; for instance, +/// `std::cmp::PartialEq`. It's represented as a sequence of identifiers, +/// along with a bunch of supporting information. +#[derive(Debug, HashStable_Generic)] +pub struct Path<'hir> { + pub span: Span, + /// The resolution for the path. + pub res: Res, + /// The segments in the path: the things separated by `::`. + pub segments: &'hir [PathSegment<'hir>], +} + +impl Path<'_> { + pub fn is_global(&self) -> bool { + !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot + } +} + +/// A segment of a path: an identifier, an optional lifetime, and a set of +/// types. +#[derive(Debug, HashStable_Generic)] +pub struct PathSegment<'hir> { + /// The identifier portion of this path segment. + pub ident: Ident, + // `id` and `res` are optional. We currently only use these in save-analysis, + // any path segments without these will not have save-analysis info and + // therefore will not have 'jump to def' in IDEs, but otherwise will not be + // affected. (In general, we don't bother to get the defs for synthesized + // segments, only for segments which have come from the AST). + pub hir_id: Option<HirId>, + pub res: Option<Res>, + + /// Type/lifetime parameters attached to this path. They come in + /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`. Note that + /// this is more than just simple syntactic sugar; the use of + /// parens affects the region binding rules, so we preserve the + /// distinction. + pub args: Option<&'hir GenericArgs<'hir>>, + + /// Whether to infer remaining type parameters, if any. + /// This only applies to expression and pattern paths, and + /// out of those only the segments with no type parameters + /// to begin with, e.g., `Vec::new` is `<Vec<..>>::new::<..>`. + pub infer_args: bool, +} + +impl<'hir> PathSegment<'hir> { + /// Converts an identifier to the corresponding segment. + pub fn from_ident(ident: Ident) -> PathSegment<'hir> { + PathSegment { ident, hir_id: None, res: None, infer_args: true, args: None } + } + + pub fn invalid() -> Self { + Self::from_ident(Ident::empty()) + } + + pub fn args(&self) -> &GenericArgs<'hir> { + if let Some(ref args) = self.args { + args + } else { + const DUMMY: &GenericArgs<'_> = &GenericArgs::none(); + DUMMY + } + } +} + +#[derive(Encodable, Debug, HashStable_Generic)] +pub struct ConstArg { + pub value: AnonConst, + pub span: Span, +} + +#[derive(Encodable, Debug, HashStable_Generic)] +pub struct InferArg { + pub hir_id: HirId, + pub span: Span, +} + +impl InferArg { + pub fn to_ty(&self) -> Ty<'_> { + Ty { kind: TyKind::Infer, span: self.span, hir_id: self.hir_id } + } +} + +#[derive(Debug, HashStable_Generic)] +pub enum GenericArg<'hir> { + Lifetime(Lifetime), + Type(Ty<'hir>), + Const(ConstArg), + Infer(InferArg), +} + +impl GenericArg<'_> { + pub fn span(&self) -> Span { + match self { + GenericArg::Lifetime(l) => l.span, + GenericArg::Type(t) => t.span, + GenericArg::Const(c) => c.span, + GenericArg::Infer(i) => i.span, + } + } + + pub fn id(&self) -> HirId { + match self { + GenericArg::Lifetime(l) => l.hir_id, + GenericArg::Type(t) => t.hir_id, + GenericArg::Const(c) => c.value.hir_id, + GenericArg::Infer(i) => i.hir_id, + } + } + + pub fn is_synthetic(&self) -> bool { + matches!(self, GenericArg::Lifetime(lifetime) if lifetime.name.ident() == Ident::empty()) + } + + pub fn descr(&self) -> &'static str { + match self { + GenericArg::Lifetime(_) => "lifetime", + GenericArg::Type(_) => "type", + GenericArg::Const(_) => "constant", + GenericArg::Infer(_) => "inferred", + } + } + + pub fn to_ord(&self) -> ast::ParamKindOrd { + match self { + GenericArg::Lifetime(_) => ast::ParamKindOrd::Lifetime, + GenericArg::Type(_) => ast::ParamKindOrd::Type, + GenericArg::Const(_) => ast::ParamKindOrd::Const, + GenericArg::Infer(_) => ast::ParamKindOrd::Infer, + } + } + + pub fn is_ty_or_const(&self) -> bool { + match self { + GenericArg::Lifetime(_) => false, + GenericArg::Type(_) | GenericArg::Const(_) | GenericArg::Infer(_) => true, + } + } +} + +#[derive(Debug, HashStable_Generic)] +pub struct GenericArgs<'hir> { + /// The generic arguments for this path segment. + pub args: &'hir [GenericArg<'hir>], + /// Bindings (equality constraints) on associated types, if present. + /// E.g., `Foo<A = Bar>`. + pub bindings: &'hir [TypeBinding<'hir>], + /// Were arguments written in parenthesized form `Fn(T) -> U`? + /// This is required mostly for pretty-printing and diagnostics, + /// but also for changing lifetime elision rules to be "function-like". + pub parenthesized: bool, + /// The span encompassing arguments and the surrounding brackets `<>` or `()` + /// Foo<A, B, AssocTy = D> Fn(T, U, V) -> W + /// ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^ + /// Note that this may be: + /// - empty, if there are no generic brackets (but there may be hidden lifetimes) + /// - dummy, if this was generated while desugaring + pub span_ext: Span, +} + +impl<'hir> GenericArgs<'hir> { + pub const fn none() -> Self { + Self { args: &[], bindings: &[], parenthesized: false, span_ext: DUMMY_SP } + } + + pub fn inputs(&self) -> &[Ty<'hir>] { + if self.parenthesized { + for arg in self.args { + match arg { + GenericArg::Lifetime(_) => {} + GenericArg::Type(ref ty) => { + if let TyKind::Tup(ref tys) = ty.kind { + return tys; + } + break; + } + GenericArg::Const(_) => {} + GenericArg::Infer(_) => {} + } + } + } + panic!("GenericArgs::inputs: not a `Fn(T) -> U`"); + } + + #[inline] + pub fn has_type_params(&self) -> bool { + self.args.iter().any(|arg| matches!(arg, GenericArg::Type(_))) + } + + pub fn has_err(&self) -> bool { + self.args.iter().any(|arg| match arg { + GenericArg::Type(ty) => matches!(ty.kind, TyKind::Err), + _ => false, + }) || self.bindings.iter().any(|arg| match arg.kind { + TypeBindingKind::Equality { term: Term::Ty(ty) } => matches!(ty.kind, TyKind::Err), + _ => false, + }) + } + + #[inline] + pub fn num_type_params(&self) -> usize { + self.args.iter().filter(|arg| matches!(arg, GenericArg::Type(_))).count() + } + + #[inline] + pub fn num_lifetime_params(&self) -> usize { + self.args.iter().filter(|arg| matches!(arg, GenericArg::Lifetime(_))).count() + } + + #[inline] + pub fn has_lifetime_params(&self) -> bool { + self.args.iter().any(|arg| matches!(arg, GenericArg::Lifetime(_))) + } + + #[inline] + pub fn num_generic_params(&self) -> usize { + self.args.iter().filter(|arg| !matches!(arg, GenericArg::Lifetime(_))).count() + } + + /// The span encompassing the text inside the surrounding brackets. + /// It will also include bindings if they aren't in the form `-> Ret` + /// Returns `None` if the span is empty (e.g. no brackets) or dummy + pub fn span(&self) -> Option<Span> { + let span_ext = self.span_ext()?; + Some(span_ext.with_lo(span_ext.lo() + BytePos(1)).with_hi(span_ext.hi() - BytePos(1))) + } + + /// Returns span encompassing arguments and their surrounding `<>` or `()` + pub fn span_ext(&self) -> Option<Span> { + Some(self.span_ext).filter(|span| !span.is_empty()) + } + + pub fn is_empty(&self) -> bool { + self.args.is_empty() + } +} + +/// A modifier on a bound, currently this is only used for `?Sized`, where the +/// modifier is `Maybe`. Negative bounds should also be handled here. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Hash, Debug)] +#[derive(HashStable_Generic)] +pub enum TraitBoundModifier { + None, + Maybe, + MaybeConst, +} + +/// The AST represents all type param bounds as types. +/// `typeck::collect::compute_bounds` matches these against +/// the "special" built-in traits (see `middle::lang_items`) and +/// detects `Copy`, `Send` and `Sync`. +#[derive(Clone, Debug, HashStable_Generic)] +pub enum GenericBound<'hir> { + Trait(PolyTraitRef<'hir>, TraitBoundModifier), + // FIXME(davidtwco): Introduce `PolyTraitRef::LangItem` + LangItemTrait(LangItem, Span, HirId, &'hir GenericArgs<'hir>), + Outlives(Lifetime), +} + +impl GenericBound<'_> { + pub fn trait_ref(&self) -> Option<&TraitRef<'_>> { + match self { + GenericBound::Trait(data, _) => Some(&data.trait_ref), + _ => None, + } + } + + pub fn span(&self) -> Span { + match self { + GenericBound::Trait(t, ..) => t.span, + GenericBound::LangItemTrait(_, span, ..) => *span, + GenericBound::Outlives(l) => l.span, + } + } +} + +pub type GenericBounds<'hir> = &'hir [GenericBound<'hir>]; + +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Debug, HashStable_Generic)] +pub enum LifetimeParamKind { + // Indicates that the lifetime definition was explicitly declared (e.g., in + // `fn foo<'a>(x: &'a u8) -> &'a u8 { x }`). + Explicit, + + // Indication that the lifetime was elided (e.g., in both cases in + // `fn foo(x: &u8) -> &'_ u8 { x }`). + Elided, + + // Indication that the lifetime name was somehow in error. + Error, +} + +#[derive(Debug, HashStable_Generic)] +pub enum GenericParamKind<'hir> { + /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`). + Lifetime { + kind: LifetimeParamKind, + }, + Type { + default: Option<&'hir Ty<'hir>>, + synthetic: bool, + }, + Const { + ty: &'hir Ty<'hir>, + /// Optional default value for the const generic param + default: Option<AnonConst>, + }, +} + +#[derive(Debug, HashStable_Generic)] +pub struct GenericParam<'hir> { + pub hir_id: HirId, + pub name: ParamName, + pub span: Span, + pub pure_wrt_drop: bool, + pub kind: GenericParamKind<'hir>, + pub colon_span: Option<Span>, +} + +impl<'hir> GenericParam<'hir> { + /// Synthetic type-parameters are inserted after normal ones. + /// In order for normal parameters to be able to refer to synthetic ones, + /// scans them first. + pub fn is_impl_trait(&self) -> bool { + matches!(self.kind, GenericParamKind::Type { synthetic: true, .. }) + } + + /// This can happen for `async fn`, e.g. `async fn f<'_>(&'_ self)`. + /// + /// See `lifetime_to_generic_param` in `rustc_ast_lowering` for more information. + pub fn is_elided_lifetime(&self) -> bool { + matches!(self.kind, GenericParamKind::Lifetime { kind: LifetimeParamKind::Elided }) + } +} + +#[derive(Default)] +pub struct GenericParamCount { + pub lifetimes: usize, + pub types: usize, + pub consts: usize, + pub infer: usize, +} + +/// Represents lifetimes and type parameters attached to a declaration +/// of a function, enum, trait, etc. +#[derive(Debug, HashStable_Generic)] +pub struct Generics<'hir> { + pub params: &'hir [GenericParam<'hir>], + pub predicates: &'hir [WherePredicate<'hir>], + pub has_where_clause_predicates: bool, + pub where_clause_span: Span, + pub span: Span, +} + +impl<'hir> Generics<'hir> { + pub const fn empty() -> &'hir Generics<'hir> { + const NOPE: Generics<'_> = Generics { + params: &[], + predicates: &[], + has_where_clause_predicates: false, + where_clause_span: DUMMY_SP, + span: DUMMY_SP, + }; + &NOPE + } + + pub fn get_named(&self, name: Symbol) -> Option<&GenericParam<'hir>> { + for param in self.params { + if name == param.name.ident().name { + return Some(param); + } + } + None + } + + pub fn spans(&self) -> MultiSpan { + if self.params.is_empty() { + self.span.into() + } else { + self.params.iter().map(|p| p.span).collect::<Vec<Span>>().into() + } + } + + /// If there are generic parameters, return where to introduce a new one. + pub fn span_for_param_suggestion(&self) -> Option<Span> { + if self.params.iter().any(|p| self.span.contains(p.span)) { + // `fn foo<A>(t: impl Trait)` + // ^ suggest `, T: Trait` here + let span = self.span.with_lo(self.span.hi() - BytePos(1)).shrink_to_lo(); + Some(span) + } else { + None + } + } + + /// `Span` where further predicates would be suggested, accounting for trailing commas, like + /// in `fn foo<T>(t: T) where T: Foo,` so we don't suggest two trailing commas. + pub fn tail_span_for_predicate_suggestion(&self) -> Span { + let end = self.where_clause_span.shrink_to_hi(); + if self.has_where_clause_predicates { + self.predicates + .iter() + .filter(|p| p.in_where_clause()) + .last() + .map_or(end, |p| p.span()) + .shrink_to_hi() + .to(end) + } else { + end + } + } + + pub fn add_where_or_trailing_comma(&self) -> &'static str { + if self.has_where_clause_predicates { + "," + } else if self.where_clause_span.is_empty() { + " where" + } else { + // No where clause predicates, but we have `where` token + "" + } + } + + pub fn bounds_for_param( + &self, + param_def_id: LocalDefId, + ) -> impl Iterator<Item = &WhereBoundPredicate<'hir>> { + self.predicates.iter().filter_map(move |pred| match pred { + WherePredicate::BoundPredicate(bp) if bp.is_param_bound(param_def_id.to_def_id()) => { + Some(bp) + } + _ => None, + }) + } + + pub fn outlives_for_param( + &self, + param_def_id: LocalDefId, + ) -> impl Iterator<Item = &WhereRegionPredicate<'_>> { + self.predicates.iter().filter_map(move |pred| match pred { + WherePredicate::RegionPredicate(rp) if rp.is_param_bound(param_def_id) => Some(rp), + _ => None, + }) + } + + pub fn bounds_span_for_suggestions(&self, param_def_id: LocalDefId) -> Option<Span> { + self.bounds_for_param(param_def_id).flat_map(|bp| bp.bounds.iter().rev()).find_map( + |bound| { + // We include bounds that come from a `#[derive(_)]` but point at the user's code, + // as we use this method to get a span appropriate for suggestions. + let bs = bound.span(); + if bs.can_be_used_for_suggestions() { Some(bs.shrink_to_hi()) } else { None } + }, + ) + } + + pub fn span_for_predicate_removal(&self, pos: usize) -> Span { + let predicate = &self.predicates[pos]; + let span = predicate.span(); + + if !predicate.in_where_clause() { + // <T: ?Sized, U> + // ^^^^^^^^ + return span; + } + + // We need to find out which comma to remove. + if pos < self.predicates.len() - 1 { + let next_pred = &self.predicates[pos + 1]; + if next_pred.in_where_clause() { + // where T: ?Sized, Foo: Bar, + // ^^^^^^^^^^^ + return span.until(next_pred.span()); + } + } + + if pos > 0 { + let prev_pred = &self.predicates[pos - 1]; + if prev_pred.in_where_clause() { + // where Foo: Bar, T: ?Sized, + // ^^^^^^^^^^^ + return prev_pred.span().shrink_to_hi().to(span); + } + } + + // This is the only predicate in the where clause. + // where T: ?Sized + // ^^^^^^^^^^^^^^^ + self.where_clause_span + } + + pub fn span_for_bound_removal(&self, predicate_pos: usize, bound_pos: usize) -> Span { + let predicate = &self.predicates[predicate_pos]; + let bounds = predicate.bounds(); + + if bounds.len() == 1 { + return self.span_for_predicate_removal(predicate_pos); + } + + let span = bounds[bound_pos].span(); + if bound_pos == 0 { + // where T: ?Sized + Bar, Foo: Bar, + // ^^^^^^^^^ + span.to(bounds[1].span().shrink_to_lo()) + } else { + // where T: Bar + ?Sized, Foo: Bar, + // ^^^^^^^^^ + bounds[bound_pos - 1].span().shrink_to_hi().to(span) + } + } +} + +/// A single predicate in a where-clause. +#[derive(Debug, HashStable_Generic)] +pub enum WherePredicate<'hir> { + /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`). + BoundPredicate(WhereBoundPredicate<'hir>), + /// A lifetime predicate (e.g., `'a: 'b + 'c`). + RegionPredicate(WhereRegionPredicate<'hir>), + /// An equality predicate (unsupported). + EqPredicate(WhereEqPredicate<'hir>), +} + +impl<'hir> WherePredicate<'hir> { + pub fn span(&self) -> Span { + match self { + WherePredicate::BoundPredicate(p) => p.span, + WherePredicate::RegionPredicate(p) => p.span, + WherePredicate::EqPredicate(p) => p.span, + } + } + + pub fn in_where_clause(&self) -> bool { + match self { + WherePredicate::BoundPredicate(p) => p.origin == PredicateOrigin::WhereClause, + WherePredicate::RegionPredicate(p) => p.in_where_clause, + WherePredicate::EqPredicate(_) => false, + } + } + + pub fn bounds(&self) -> GenericBounds<'hir> { + match self { + WherePredicate::BoundPredicate(p) => p.bounds, + WherePredicate::RegionPredicate(p) => p.bounds, + WherePredicate::EqPredicate(_) => &[], + } + } +} + +#[derive(Copy, Clone, Debug, HashStable_Generic, PartialEq, Eq)] +pub enum PredicateOrigin { + WhereClause, + GenericParam, + ImplTrait, +} + +/// A type bound (e.g., `for<'c> Foo: Send + Clone + 'c`). +#[derive(Debug, HashStable_Generic)] +pub struct WhereBoundPredicate<'hir> { + pub span: Span, + /// Origin of the predicate. + pub origin: PredicateOrigin, + /// Any generics from a `for` binding. + pub bound_generic_params: &'hir [GenericParam<'hir>], + /// The type being bounded. + pub bounded_ty: &'hir Ty<'hir>, + /// Trait and lifetime bounds (e.g., `Clone + Send + 'static`). + pub bounds: GenericBounds<'hir>, +} + +impl<'hir> WhereBoundPredicate<'hir> { + /// Returns `true` if `param_def_id` matches the `bounded_ty` of this predicate. + pub fn is_param_bound(&self, param_def_id: DefId) -> bool { + self.bounded_ty.as_generic_param().map_or(false, |(def_id, _)| def_id == param_def_id) + } +} + +/// A lifetime predicate (e.g., `'a: 'b + 'c`). +#[derive(Debug, HashStable_Generic)] +pub struct WhereRegionPredicate<'hir> { + pub span: Span, + pub in_where_clause: bool, + pub lifetime: Lifetime, + pub bounds: GenericBounds<'hir>, +} + +impl<'hir> WhereRegionPredicate<'hir> { + /// Returns `true` if `param_def_id` matches the `lifetime` of this predicate. + pub fn is_param_bound(&self, param_def_id: LocalDefId) -> bool { + match self.lifetime.name { + LifetimeName::Param(id, _) => id == param_def_id, + _ => false, + } + } +} + +/// An equality predicate (e.g., `T = int`); currently unsupported. +#[derive(Debug, HashStable_Generic)] +pub struct WhereEqPredicate<'hir> { + pub hir_id: HirId, + pub span: Span, + pub lhs_ty: &'hir Ty<'hir>, + pub rhs_ty: &'hir Ty<'hir>, +} + +/// HIR node coupled with its parent's id in the same HIR owner. +/// +/// The parent is trash when the node is a HIR owner. +#[derive(Clone, Debug)] +pub struct ParentedNode<'tcx> { + pub parent: ItemLocalId, + pub node: Node<'tcx>, +} + +/// Attributes owned by a HIR owner. +#[derive(Debug)] +pub struct AttributeMap<'tcx> { + pub map: SortedMap<ItemLocalId, &'tcx [Attribute]>, + pub hash: Fingerprint, +} + +impl<'tcx> AttributeMap<'tcx> { + pub const EMPTY: &'static AttributeMap<'static> = + &AttributeMap { map: SortedMap::new(), hash: Fingerprint::ZERO }; + + #[inline] + pub fn get(&self, id: ItemLocalId) -> &'tcx [Attribute] { + self.map.get(&id).copied().unwrap_or(&[]) + } +} + +/// Map of all HIR nodes inside the current owner. +/// These nodes are mapped by `ItemLocalId` alongside the index of their parent node. +/// The HIR tree, including bodies, is pre-hashed. +pub struct OwnerNodes<'tcx> { + /// Pre-computed hash of the full HIR. + pub hash_including_bodies: Fingerprint, + /// Pre-computed hash of the item signature, sithout recursing into the body. + pub hash_without_bodies: Fingerprint, + /// Full HIR for the current owner. + // The zeroth node's parent should never be accessed: the owner's parent is computed by the + // hir_owner_parent query. It is set to `ItemLocalId::INVALID` to force an ICE if accidentally + // used. + pub nodes: IndexVec<ItemLocalId, Option<ParentedNode<'tcx>>>, + /// Content of local bodies. + pub bodies: SortedMap<ItemLocalId, &'tcx Body<'tcx>>, + /// Non-owning definitions contained in this owner. + pub local_id_to_def_id: SortedMap<ItemLocalId, LocalDefId>, +} + +impl<'tcx> OwnerNodes<'tcx> { + pub fn node(&self) -> OwnerNode<'tcx> { + use rustc_index::vec::Idx; + let node = self.nodes[ItemLocalId::new(0)].as_ref().unwrap().node; + let node = node.as_owner().unwrap(); // Indexing must ensure it is an OwnerNode. + node + } +} + +impl fmt::Debug for OwnerNodes<'_> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("OwnerNodes") + .field("node", &self.nodes[ItemLocalId::from_u32(0)]) + .field("bodies", &self.bodies) + .field("local_id_to_def_id", &self.local_id_to_def_id) + .field("hash_without_bodies", &self.hash_without_bodies) + .field("hash_including_bodies", &self.hash_including_bodies) + .finish() + } +} + +/// Full information resulting from lowering an AST node. +#[derive(Debug, HashStable_Generic)] +pub struct OwnerInfo<'hir> { + /// Contents of the HIR. + pub nodes: OwnerNodes<'hir>, + /// Map from each nested owner to its parent's local id. + pub parenting: FxHashMap<LocalDefId, ItemLocalId>, + /// Collected attributes of the HIR nodes. + pub attrs: AttributeMap<'hir>, + /// Map indicating what traits are in scope for places where this + /// is relevant; generated by resolve. + pub trait_map: FxHashMap<ItemLocalId, Box<[TraitCandidate]>>, +} + +impl<'tcx> OwnerInfo<'tcx> { + #[inline] + pub fn node(&self) -> OwnerNode<'tcx> { + self.nodes.node() + } +} + +#[derive(Copy, Clone, Debug, HashStable_Generic)] +pub enum MaybeOwner<T> { + Owner(T), + NonOwner(HirId), + /// Used as a placeholder for unused LocalDefId. + Phantom, +} + +impl<T> MaybeOwner<T> { + pub fn as_owner(self) -> Option<T> { + match self { + MaybeOwner::Owner(i) => Some(i), + MaybeOwner::NonOwner(_) | MaybeOwner::Phantom => None, + } + } + + pub fn map<U>(self, f: impl FnOnce(T) -> U) -> MaybeOwner<U> { + match self { + MaybeOwner::Owner(i) => MaybeOwner::Owner(f(i)), + MaybeOwner::NonOwner(hir_id) => MaybeOwner::NonOwner(hir_id), + MaybeOwner::Phantom => MaybeOwner::Phantom, + } + } + + pub fn unwrap(self) -> T { + match self { + MaybeOwner::Owner(i) => i, + MaybeOwner::NonOwner(_) | MaybeOwner::Phantom => panic!("Not a HIR owner"), + } + } +} + +/// The top-level data structure that stores the entire contents of +/// the crate currently being compiled. +/// +/// For more details, see the [rustc dev guide]. +/// +/// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html +#[derive(Debug)] +pub struct Crate<'hir> { + pub owners: IndexVec<LocalDefId, MaybeOwner<&'hir OwnerInfo<'hir>>>, + pub hir_hash: Fingerprint, +} + +#[derive(Debug, HashStable_Generic)] +pub struct Closure<'hir> { + pub binder: ClosureBinder, + pub capture_clause: CaptureBy, + pub bound_generic_params: &'hir [GenericParam<'hir>], + pub fn_decl: &'hir FnDecl<'hir>, + pub body: BodyId, + pub fn_decl_span: Span, + pub movability: Option<Movability>, +} + +/// A block of statements `{ .. }`, which may have a label (in this case the +/// `targeted_by_break` field will be `true`) and may be `unsafe` by means of +/// the `rules` being anything but `DefaultBlock`. +#[derive(Debug, HashStable_Generic)] +pub struct Block<'hir> { + /// Statements in a block. + pub stmts: &'hir [Stmt<'hir>], + /// An expression at the end of the block + /// without a semicolon, if any. + pub expr: Option<&'hir Expr<'hir>>, + #[stable_hasher(ignore)] + pub hir_id: HirId, + /// Distinguishes between `unsafe { ... }` and `{ ... }`. + pub rules: BlockCheckMode, + pub span: Span, + /// If true, then there may exist `break 'a` values that aim to + /// break out of this block early. + /// Used by `'label: {}` blocks and by `try {}` blocks. + pub targeted_by_break: bool, +} + +impl<'hir> Block<'hir> { + pub fn innermost_block(&self) -> &Block<'hir> { + let mut block = self; + while let Some(Expr { kind: ExprKind::Block(inner_block, _), .. }) = block.expr { + block = inner_block; + } + block + } +} + +#[derive(Debug, HashStable_Generic)] +pub struct Pat<'hir> { + #[stable_hasher(ignore)] + pub hir_id: HirId, + pub kind: PatKind<'hir>, + pub span: Span, + // Whether to use default binding modes. + // At present, this is false only for destructuring assignment. + pub default_binding_modes: bool, +} + +impl<'hir> Pat<'hir> { + // FIXME(#19596) this is a workaround, but there should be a better way + fn walk_short_(&self, it: &mut impl FnMut(&Pat<'hir>) -> bool) -> bool { + if !it(self) { + return false; + } + + use PatKind::*; + match self.kind { + Wild | Lit(_) | Range(..) | Binding(.., None) | Path(_) => true, + Box(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_short_(it), + Struct(_, fields, _) => fields.iter().all(|field| field.pat.walk_short_(it)), + TupleStruct(_, s, _) | Tuple(s, _) | Or(s) => s.iter().all(|p| p.walk_short_(it)), + Slice(before, slice, after) => { + before.iter().chain(slice).chain(after.iter()).all(|p| p.walk_short_(it)) + } + } + } + + /// Walk the pattern in left-to-right order, + /// short circuiting (with `.all(..)`) if `false` is returned. + /// + /// Note that when visiting e.g. `Tuple(ps)`, + /// if visiting `ps[0]` returns `false`, + /// then `ps[1]` will not be visited. + pub fn walk_short(&self, mut it: impl FnMut(&Pat<'hir>) -> bool) -> bool { + self.walk_short_(&mut it) + } + + // FIXME(#19596) this is a workaround, but there should be a better way + fn walk_(&self, it: &mut impl FnMut(&Pat<'hir>) -> bool) { + if !it(self) { + return; + } + + use PatKind::*; + match self.kind { + Wild | Lit(_) | Range(..) | Binding(.., None) | Path(_) => {} + Box(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_(it), + Struct(_, fields, _) => fields.iter().for_each(|field| field.pat.walk_(it)), + TupleStruct(_, s, _) | Tuple(s, _) | Or(s) => s.iter().for_each(|p| p.walk_(it)), + Slice(before, slice, after) => { + before.iter().chain(slice).chain(after.iter()).for_each(|p| p.walk_(it)) + } + } + } + + /// Walk the pattern in left-to-right order. + /// + /// If `it(pat)` returns `false`, the children are not visited. + pub fn walk(&self, mut it: impl FnMut(&Pat<'hir>) -> bool) { + self.walk_(&mut it) + } + + /// Walk the pattern in left-to-right order. + /// + /// If you always want to recurse, prefer this method over `walk`. + pub fn walk_always(&self, mut it: impl FnMut(&Pat<'_>)) { + self.walk(|p| { + it(p); + true + }) + } +} + +/// A single field in a struct pattern. +/// +/// Patterns like the fields of Foo `{ x, ref y, ref mut z }` +/// are treated the same as` x: x, y: ref y, z: ref mut z`, +/// except `is_shorthand` is true. +#[derive(Debug, HashStable_Generic)] +pub struct PatField<'hir> { + #[stable_hasher(ignore)] + pub hir_id: HirId, + /// The identifier for the field. + pub ident: Ident, + /// The pattern the field is destructured to. + pub pat: &'hir Pat<'hir>, + pub is_shorthand: bool, + pub span: Span, +} + +/// Explicit binding annotations given in the HIR for a binding. Note +/// that this is not the final binding *mode* that we infer after type +/// inference. +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum BindingAnnotation { + /// No binding annotation given: this means that the final binding mode + /// will depend on whether we have skipped through a `&` reference + /// when matching. For example, the `x` in `Some(x)` will have binding + /// mode `None`; if you do `let Some(x) = &Some(22)`, it will + /// ultimately be inferred to be by-reference. + /// + /// Note that implicit reference skipping is not implemented yet (#42640). + Unannotated, + + /// Annotated with `mut x` -- could be either ref or not, similar to `None`. + Mutable, + + /// Annotated as `ref`, like `ref x` + Ref, + + /// Annotated as `ref mut x`. + RefMut, +} + +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum RangeEnd { + Included, + Excluded, +} + +impl fmt::Display for RangeEnd { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(match self { + RangeEnd::Included => "..=", + RangeEnd::Excluded => "..", + }) + } +} + +#[derive(Debug, HashStable_Generic)] +pub enum PatKind<'hir> { + /// Represents a wildcard pattern (i.e., `_`). + Wild, + + /// A fresh binding `ref mut binding @ OPT_SUBPATTERN`. + /// The `HirId` is the canonical ID for the variable being bound, + /// (e.g., in `Ok(x) | Err(x)`, both `x` use the same canonical ID), + /// which is the pattern ID of the first `x`. + Binding(BindingAnnotation, HirId, Ident, Option<&'hir Pat<'hir>>), + + /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`). + /// The `bool` is `true` in the presence of a `..`. + Struct(QPath<'hir>, &'hir [PatField<'hir>], bool), + + /// A tuple struct/variant pattern `Variant(x, y, .., z)`. + /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position. + /// `0 <= position <= subpats.len()` + TupleStruct(QPath<'hir>, &'hir [Pat<'hir>], Option<usize>), + + /// An or-pattern `A | B | C`. + /// Invariant: `pats.len() >= 2`. + Or(&'hir [Pat<'hir>]), + + /// A path pattern for a unit struct/variant or a (maybe-associated) constant. + Path(QPath<'hir>), + + /// A tuple pattern (e.g., `(a, b)`). + /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position. + /// `0 <= position <= subpats.len()` + Tuple(&'hir [Pat<'hir>], Option<usize>), + + /// A `box` pattern. + Box(&'hir Pat<'hir>), + + /// A reference pattern (e.g., `&mut (a, b)`). + Ref(&'hir Pat<'hir>, Mutability), + + /// A literal. + Lit(&'hir Expr<'hir>), + + /// A range pattern (e.g., `1..=2` or `1..2`). + Range(Option<&'hir Expr<'hir>>, Option<&'hir Expr<'hir>>, RangeEnd), + + /// A slice pattern, `[before_0, ..., before_n, (slice, after_0, ..., after_n)?]`. + /// + /// Here, `slice` is lowered from the syntax `($binding_mode $ident @)? ..`. + /// If `slice` exists, then `after` can be non-empty. + /// + /// The representation for e.g., `[a, b, .., c, d]` is: + /// ```ignore (illustrative) + /// PatKind::Slice([Binding(a), Binding(b)], Some(Wild), [Binding(c), Binding(d)]) + /// ``` + Slice(&'hir [Pat<'hir>], Option<&'hir Pat<'hir>>, &'hir [Pat<'hir>]), +} + +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum BinOpKind { + /// The `+` operator (addition). + Add, + /// The `-` operator (subtraction). + Sub, + /// The `*` operator (multiplication). + Mul, + /// The `/` operator (division). + Div, + /// The `%` operator (modulus). + Rem, + /// The `&&` operator (logical and). + And, + /// The `||` operator (logical or). + Or, + /// The `^` operator (bitwise xor). + BitXor, + /// The `&` operator (bitwise and). + BitAnd, + /// The `|` operator (bitwise or). + BitOr, + /// The `<<` operator (shift left). + Shl, + /// The `>>` operator (shift right). + Shr, + /// The `==` operator (equality). + Eq, + /// The `<` operator (less than). + Lt, + /// The `<=` operator (less than or equal to). + Le, + /// The `!=` operator (not equal to). + Ne, + /// The `>=` operator (greater than or equal to). + Ge, + /// The `>` operator (greater than). + Gt, +} + +impl BinOpKind { + pub fn as_str(self) -> &'static str { + match self { + BinOpKind::Add => "+", + BinOpKind::Sub => "-", + BinOpKind::Mul => "*", + BinOpKind::Div => "/", + BinOpKind::Rem => "%", + BinOpKind::And => "&&", + BinOpKind::Or => "||", + BinOpKind::BitXor => "^", + BinOpKind::BitAnd => "&", + BinOpKind::BitOr => "|", + BinOpKind::Shl => "<<", + BinOpKind::Shr => ">>", + BinOpKind::Eq => "==", + BinOpKind::Lt => "<", + BinOpKind::Le => "<=", + BinOpKind::Ne => "!=", + BinOpKind::Ge => ">=", + BinOpKind::Gt => ">", + } + } + + pub fn is_lazy(self) -> bool { + matches!(self, BinOpKind::And | BinOpKind::Or) + } + + pub fn is_shift(self) -> bool { + matches!(self, BinOpKind::Shl | BinOpKind::Shr) + } + + pub fn is_comparison(self) -> bool { + match self { + BinOpKind::Eq + | BinOpKind::Lt + | BinOpKind::Le + | BinOpKind::Ne + | BinOpKind::Gt + | BinOpKind::Ge => true, + BinOpKind::And + | BinOpKind::Or + | BinOpKind::Add + | BinOpKind::Sub + | BinOpKind::Mul + | BinOpKind::Div + | BinOpKind::Rem + | BinOpKind::BitXor + | BinOpKind::BitAnd + | BinOpKind::BitOr + | BinOpKind::Shl + | BinOpKind::Shr => false, + } + } + + /// Returns `true` if the binary operator takes its arguments by value. + pub fn is_by_value(self) -> bool { + !self.is_comparison() + } +} + +impl Into<ast::BinOpKind> for BinOpKind { + fn into(self) -> ast::BinOpKind { + match self { + BinOpKind::Add => ast::BinOpKind::Add, + BinOpKind::Sub => ast::BinOpKind::Sub, + BinOpKind::Mul => ast::BinOpKind::Mul, + BinOpKind::Div => ast::BinOpKind::Div, + BinOpKind::Rem => ast::BinOpKind::Rem, + BinOpKind::And => ast::BinOpKind::And, + BinOpKind::Or => ast::BinOpKind::Or, + BinOpKind::BitXor => ast::BinOpKind::BitXor, + BinOpKind::BitAnd => ast::BinOpKind::BitAnd, + BinOpKind::BitOr => ast::BinOpKind::BitOr, + BinOpKind::Shl => ast::BinOpKind::Shl, + BinOpKind::Shr => ast::BinOpKind::Shr, + BinOpKind::Eq => ast::BinOpKind::Eq, + BinOpKind::Lt => ast::BinOpKind::Lt, + BinOpKind::Le => ast::BinOpKind::Le, + BinOpKind::Ne => ast::BinOpKind::Ne, + BinOpKind::Ge => ast::BinOpKind::Ge, + BinOpKind::Gt => ast::BinOpKind::Gt, + } + } +} + +pub type BinOp = Spanned<BinOpKind>; + +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum UnOp { + /// The `*` operator (dereferencing). + Deref, + /// The `!` operator (logical negation). + Not, + /// The `-` operator (negation). + Neg, +} + +impl UnOp { + pub fn as_str(self) -> &'static str { + match self { + Self::Deref => "*", + Self::Not => "!", + Self::Neg => "-", + } + } + + /// Returns `true` if the unary operator takes its argument by value. + pub fn is_by_value(self) -> bool { + matches!(self, Self::Neg | Self::Not) + } +} + +/// A statement. +#[derive(Debug, HashStable_Generic)] +pub struct Stmt<'hir> { + pub hir_id: HirId, + pub kind: StmtKind<'hir>, + pub span: Span, +} + +/// The contents of a statement. +#[derive(Debug, HashStable_Generic)] +pub enum StmtKind<'hir> { + /// A local (`let`) binding. + Local(&'hir Local<'hir>), + + /// An item binding. + Item(ItemId), + + /// An expression without a trailing semi-colon (must have unit type). + Expr(&'hir Expr<'hir>), + + /// An expression with a trailing semi-colon (may have any type). + Semi(&'hir Expr<'hir>), +} + +/// Represents a `let` statement (i.e., `let <pat>:<ty> = <expr>;`). +#[derive(Debug, HashStable_Generic)] +pub struct Local<'hir> { + pub pat: &'hir Pat<'hir>, + /// Type annotation, if any (otherwise the type will be inferred). + pub ty: Option<&'hir Ty<'hir>>, + /// Initializer expression to set the value, if any. + pub init: Option<&'hir Expr<'hir>>, + /// Else block for a `let...else` binding. + pub els: Option<&'hir Block<'hir>>, + pub hir_id: HirId, + pub span: Span, + /// Can be `ForLoopDesugar` if the `let` statement is part of a `for` loop + /// desugaring. Otherwise will be `Normal`. + pub source: LocalSource, +} + +/// Represents a single arm of a `match` expression, e.g. +/// `<pat> (if <guard>) => <body>`. +#[derive(Debug, HashStable_Generic)] +pub struct Arm<'hir> { + #[stable_hasher(ignore)] + pub hir_id: HirId, + pub span: Span, + /// If this pattern and the optional guard matches, then `body` is evaluated. + pub pat: &'hir Pat<'hir>, + /// Optional guard clause. + pub guard: Option<Guard<'hir>>, + /// The expression the arm evaluates to if this arm matches. + pub body: &'hir Expr<'hir>, +} + +/// Represents a `let <pat>[: <ty>] = <expr>` expression (not a Local), occurring in an `if-let` or +/// `let-else`, evaluating to a boolean. Typically the pattern is refutable. +/// +/// In an if-let, imagine it as `if (let <pat> = <expr>) { ... }`; in a let-else, it is part of the +/// desugaring to if-let. Only let-else supports the type annotation at present. +#[derive(Debug, HashStable_Generic)] +pub struct Let<'hir> { + pub hir_id: HirId, + pub span: Span, + pub pat: &'hir Pat<'hir>, + pub ty: Option<&'hir Ty<'hir>>, + pub init: &'hir Expr<'hir>, +} + +#[derive(Debug, HashStable_Generic)] +pub enum Guard<'hir> { + If(&'hir Expr<'hir>), + IfLet(&'hir Let<'hir>), +} + +impl<'hir> Guard<'hir> { + /// Returns the body of the guard + /// + /// In other words, returns the e in either of the following: + /// + /// - `if e` + /// - `if let x = e` + pub fn body(&self) -> &'hir Expr<'hir> { + match self { + Guard::If(e) | Guard::IfLet(Let { init: e, .. }) => e, + } + } +} + +#[derive(Debug, HashStable_Generic)] +pub struct ExprField<'hir> { + #[stable_hasher(ignore)] + pub hir_id: HirId, + pub ident: Ident, + pub expr: &'hir Expr<'hir>, + pub span: Span, + pub is_shorthand: bool, +} + +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum BlockCheckMode { + DefaultBlock, + UnsafeBlock(UnsafeSource), +} + +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum UnsafeSource { + CompilerGenerated, + UserProvided, +} + +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Hash, Debug)] +pub struct BodyId { + pub hir_id: HirId, +} + +/// The body of a function, closure, or constant value. In the case of +/// a function, the body contains not only the function body itself +/// (which is an expression), but also the argument patterns, since +/// those are something that the caller doesn't really care about. +/// +/// # Examples +/// +/// ``` +/// fn foo((x, y): (u32, u32)) -> u32 { +/// x + y +/// } +/// ``` +/// +/// Here, the `Body` associated with `foo()` would contain: +/// +/// - an `params` array containing the `(x, y)` pattern +/// - a `value` containing the `x + y` expression (maybe wrapped in a block) +/// - `generator_kind` would be `None` +/// +/// All bodies have an **owner**, which can be accessed via the HIR +/// map using `body_owner_def_id()`. +#[derive(Debug, HashStable_Generic)] +pub struct Body<'hir> { + pub params: &'hir [Param<'hir>], + pub value: Expr<'hir>, + pub generator_kind: Option<GeneratorKind>, +} + +impl<'hir> Body<'hir> { + pub fn id(&self) -> BodyId { + BodyId { hir_id: self.value.hir_id } + } + + pub fn generator_kind(&self) -> Option<GeneratorKind> { + self.generator_kind + } +} + +/// The type of source expression that caused this generator to be created. +#[derive(Clone, PartialEq, PartialOrd, Eq, Hash, Debug, Copy)] +#[derive(HashStable_Generic, Encodable, Decodable)] +pub enum GeneratorKind { + /// An explicit `async` block or the body of an async function. + Async(AsyncGeneratorKind), + + /// A generator literal created via a `yield` inside a closure. + Gen, +} + +impl fmt::Display for GeneratorKind { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self { + GeneratorKind::Async(k) => fmt::Display::fmt(k, f), + GeneratorKind::Gen => f.write_str("generator"), + } + } +} + +impl GeneratorKind { + pub fn descr(&self) -> &'static str { + match self { + GeneratorKind::Async(ask) => ask.descr(), + GeneratorKind::Gen => "generator", + } + } +} + +/// In the case of a generator created as part of an async construct, +/// which kind of async construct caused it to be created? +/// +/// This helps error messages but is also used to drive coercions in +/// type-checking (see #60424). +#[derive(Clone, PartialEq, PartialOrd, Eq, Hash, Debug, Copy)] +#[derive(HashStable_Generic, Encodable, Decodable)] +pub enum AsyncGeneratorKind { + /// An explicit `async` block written by the user. + Block, + + /// An explicit `async` closure written by the user. + Closure, + + /// The `async` block generated as the body of an async function. + Fn, +} + +impl fmt::Display for AsyncGeneratorKind { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(match self { + AsyncGeneratorKind::Block => "`async` block", + AsyncGeneratorKind::Closure => "`async` closure body", + AsyncGeneratorKind::Fn => "`async fn` body", + }) + } +} + +impl AsyncGeneratorKind { + pub fn descr(&self) -> &'static str { + match self { + AsyncGeneratorKind::Block => "`async` block", + AsyncGeneratorKind::Closure => "`async` closure body", + AsyncGeneratorKind::Fn => "`async fn` body", + } + } +} + +#[derive(Copy, Clone, Debug)] +pub enum BodyOwnerKind { + /// Functions and methods. + Fn, + + /// Closures + Closure, + + /// Constants and associated constants. + Const, + + /// Initializer of a `static` item. + Static(Mutability), +} + +impl BodyOwnerKind { + pub fn is_fn_or_closure(self) -> bool { + match self { + BodyOwnerKind::Fn | BodyOwnerKind::Closure => true, + BodyOwnerKind::Const | BodyOwnerKind::Static(_) => false, + } + } +} + +/// The kind of an item that requires const-checking. +#[derive(Clone, Copy, Debug, PartialEq, Eq)] +pub enum ConstContext { + /// A `const fn`. + ConstFn, + + /// A `static` or `static mut`. + Static(Mutability), + + /// A `const`, associated `const`, or other const context. + /// + /// Other contexts include: + /// - Array length expressions + /// - Enum discriminants + /// - Const generics + /// + /// For the most part, other contexts are treated just like a regular `const`, so they are + /// lumped into the same category. + Const, +} + +impl ConstContext { + /// A description of this const context that can appear between backticks in an error message. + /// + /// E.g. `const` or `static mut`. + pub fn keyword_name(self) -> &'static str { + match self { + Self::Const => "const", + Self::Static(Mutability::Not) => "static", + Self::Static(Mutability::Mut) => "static mut", + Self::ConstFn => "const fn", + } + } +} + +/// A colloquial, trivially pluralizable description of this const context for use in error +/// messages. +impl fmt::Display for ConstContext { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match *self { + Self::Const => write!(f, "constant"), + Self::Static(_) => write!(f, "static"), + Self::ConstFn => write!(f, "constant function"), + } + } +} + +// NOTE: `IntoDiagnosticArg` impl for `ConstContext` lives in `rustc_errors` +// due to a cyclical dependency between hir that crate. + +/// A literal. +pub type Lit = Spanned<LitKind>; + +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Debug, HashStable_Generic)] +pub enum ArrayLen { + Infer(HirId, Span), + Body(AnonConst), +} + +impl ArrayLen { + pub fn hir_id(&self) -> HirId { + match self { + &ArrayLen::Infer(hir_id, _) | &ArrayLen::Body(AnonConst { hir_id, body: _ }) => hir_id, + } + } +} + +/// A constant (expression) that's not an item or associated item, +/// but needs its own `DefId` for type-checking, const-eval, etc. +/// These are usually found nested inside types (e.g., array lengths) +/// or expressions (e.g., repeat counts), and also used to define +/// explicit discriminant values for enum variants. +/// +/// You can check if this anon const is a default in a const param +/// `const N: usize = { ... }` with `tcx.hir().opt_const_param_default_param_hir_id(..)` +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Debug, HashStable_Generic)] +pub struct AnonConst { + pub hir_id: HirId, + pub body: BodyId, +} + +/// An expression. +#[derive(Debug)] +pub struct Expr<'hir> { + pub hir_id: HirId, + pub kind: ExprKind<'hir>, + pub span: Span, +} + +impl Expr<'_> { + pub fn precedence(&self) -> ExprPrecedence { + match self.kind { + ExprKind::Box(_) => ExprPrecedence::Box, + ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock, + ExprKind::Array(_) => ExprPrecedence::Array, + ExprKind::Call(..) => ExprPrecedence::Call, + ExprKind::MethodCall(..) => ExprPrecedence::MethodCall, + ExprKind::Tup(_) => ExprPrecedence::Tup, + ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node.into()), + ExprKind::Unary(..) => ExprPrecedence::Unary, + ExprKind::Lit(_) => ExprPrecedence::Lit, + ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast, + ExprKind::DropTemps(ref expr, ..) => expr.precedence(), + ExprKind::If(..) => ExprPrecedence::If, + ExprKind::Let(..) => ExprPrecedence::Let, + ExprKind::Loop(..) => ExprPrecedence::Loop, + ExprKind::Match(..) => ExprPrecedence::Match, + ExprKind::Closure { .. } => ExprPrecedence::Closure, + ExprKind::Block(..) => ExprPrecedence::Block, + ExprKind::Assign(..) => ExprPrecedence::Assign, + ExprKind::AssignOp(..) => ExprPrecedence::AssignOp, + ExprKind::Field(..) => ExprPrecedence::Field, + ExprKind::Index(..) => ExprPrecedence::Index, + ExprKind::Path(..) => ExprPrecedence::Path, + ExprKind::AddrOf(..) => ExprPrecedence::AddrOf, + ExprKind::Break(..) => ExprPrecedence::Break, + ExprKind::Continue(..) => ExprPrecedence::Continue, + ExprKind::Ret(..) => ExprPrecedence::Ret, + ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm, + ExprKind::Struct(..) => ExprPrecedence::Struct, + ExprKind::Repeat(..) => ExprPrecedence::Repeat, + ExprKind::Yield(..) => ExprPrecedence::Yield, + ExprKind::Err => ExprPrecedence::Err, + } + } + + // Whether this looks like a place expr, without checking for deref + // adjustments. + // This will return `true` in some potentially surprising cases such as + // `CONSTANT.field`. + pub fn is_syntactic_place_expr(&self) -> bool { + self.is_place_expr(|_| true) + } + + /// Whether this is a place expression. + /// + /// `allow_projections_from` should return `true` if indexing a field or index expression based + /// on the given expression should be considered a place expression. + pub fn is_place_expr(&self, mut allow_projections_from: impl FnMut(&Self) -> bool) -> bool { + match self.kind { + ExprKind::Path(QPath::Resolved(_, ref path)) => { + matches!(path.res, Res::Local(..) | Res::Def(DefKind::Static(_), _) | Res::Err) + } + + // Type ascription inherits its place expression kind from its + // operand. See: + // https://github.com/rust-lang/rfcs/blob/master/text/0803-type-ascription.md#type-ascription-and-temporaries + ExprKind::Type(ref e, _) => e.is_place_expr(allow_projections_from), + + ExprKind::Unary(UnOp::Deref, _) => true, + + ExprKind::Field(ref base, _) | ExprKind::Index(ref base, _) => { + allow_projections_from(base) || base.is_place_expr(allow_projections_from) + } + + // Lang item paths cannot currently be local variables or statics. + ExprKind::Path(QPath::LangItem(..)) => false, + + // Partially qualified paths in expressions can only legally + // refer to associated items which are always rvalues. + ExprKind::Path(QPath::TypeRelative(..)) + | ExprKind::Call(..) + | ExprKind::MethodCall(..) + | ExprKind::Struct(..) + | ExprKind::Tup(..) + | ExprKind::If(..) + | ExprKind::Match(..) + | ExprKind::Closure { .. } + | ExprKind::Block(..) + | ExprKind::Repeat(..) + | ExprKind::Array(..) + | ExprKind::Break(..) + | ExprKind::Continue(..) + | ExprKind::Ret(..) + | ExprKind::Let(..) + | ExprKind::Loop(..) + | ExprKind::Assign(..) + | ExprKind::InlineAsm(..) + | ExprKind::AssignOp(..) + | ExprKind::Lit(_) + | ExprKind::ConstBlock(..) + | ExprKind::Unary(..) + | ExprKind::Box(..) + | ExprKind::AddrOf(..) + | ExprKind::Binary(..) + | ExprKind::Yield(..) + | ExprKind::Cast(..) + | ExprKind::DropTemps(..) + | ExprKind::Err => false, + } + } + + /// If `Self.kind` is `ExprKind::DropTemps(expr)`, drill down until we get a non-`DropTemps` + /// `Expr`. This is used in suggestions to ignore this `ExprKind` as it is semantically + /// silent, only signaling the ownership system. By doing this, suggestions that check the + /// `ExprKind` of any given `Expr` for presentation don't have to care about `DropTemps` + /// beyond remembering to call this function before doing analysis on it. + pub fn peel_drop_temps(&self) -> &Self { + let mut expr = self; + while let ExprKind::DropTemps(inner) = &expr.kind { + expr = inner; + } + expr + } + + pub fn peel_blocks(&self) -> &Self { + let mut expr = self; + while let ExprKind::Block(Block { expr: Some(inner), .. }, _) = &expr.kind { + expr = inner; + } + expr + } + + pub fn can_have_side_effects(&self) -> bool { + match self.peel_drop_temps().kind { + ExprKind::Path(_) | ExprKind::Lit(_) => false, + ExprKind::Type(base, _) + | ExprKind::Unary(_, base) + | ExprKind::Field(base, _) + | ExprKind::Index(base, _) + | ExprKind::AddrOf(.., base) + | ExprKind::Cast(base, _) => { + // This isn't exactly true for `Index` and all `Unary`, but we are using this + // method exclusively for diagnostics and there's a *cultural* pressure against + // them being used only for its side-effects. + base.can_have_side_effects() + } + ExprKind::Struct(_, fields, init) => fields + .iter() + .map(|field| field.expr) + .chain(init.into_iter()) + .all(|e| e.can_have_side_effects()), + + ExprKind::Array(args) + | ExprKind::Tup(args) + | ExprKind::Call( + Expr { + kind: + ExprKind::Path(QPath::Resolved( + None, + Path { res: Res::Def(DefKind::Ctor(_, CtorKind::Fn), _), .. }, + )), + .. + }, + args, + ) => args.iter().all(|arg| arg.can_have_side_effects()), + ExprKind::If(..) + | ExprKind::Match(..) + | ExprKind::MethodCall(..) + | ExprKind::Call(..) + | ExprKind::Closure { .. } + | ExprKind::Block(..) + | ExprKind::Repeat(..) + | ExprKind::Break(..) + | ExprKind::Continue(..) + | ExprKind::Ret(..) + | ExprKind::Let(..) + | ExprKind::Loop(..) + | ExprKind::Assign(..) + | ExprKind::InlineAsm(..) + | ExprKind::AssignOp(..) + | ExprKind::ConstBlock(..) + | ExprKind::Box(..) + | ExprKind::Binary(..) + | ExprKind::Yield(..) + | ExprKind::DropTemps(..) + | ExprKind::Err => true, + } + } + + // To a first-order approximation, is this a pattern + pub fn is_approximately_pattern(&self) -> bool { + match &self.kind { + ExprKind::Box(_) + | ExprKind::Array(_) + | ExprKind::Call(..) + | ExprKind::Tup(_) + | ExprKind::Lit(_) + | ExprKind::Path(_) + | ExprKind::Struct(..) => true, + _ => false, + } + } + + pub fn method_ident(&self) -> Option<Ident> { + match self.kind { + ExprKind::MethodCall(receiver_method, ..) => Some(receiver_method.ident), + ExprKind::Unary(_, expr) | ExprKind::AddrOf(.., expr) => expr.method_ident(), + _ => None, + } + } +} + +/// Checks if the specified expression is a built-in range literal. +/// (See: `LoweringContext::lower_expr()`). +pub fn is_range_literal(expr: &Expr<'_>) -> bool { + match expr.kind { + // All built-in range literals but `..=` and `..` desugar to `Struct`s. + ExprKind::Struct(ref qpath, _, _) => matches!( + **qpath, + QPath::LangItem( + LangItem::Range + | LangItem::RangeTo + | LangItem::RangeFrom + | LangItem::RangeFull + | LangItem::RangeToInclusive, + .. + ) + ), + + // `..=` desugars into `::std::ops::RangeInclusive::new(...)`. + ExprKind::Call(ref func, _) => { + matches!(func.kind, ExprKind::Path(QPath::LangItem(LangItem::RangeInclusiveNew, ..))) + } + + _ => false, + } +} + +#[derive(Debug, HashStable_Generic)] +pub enum ExprKind<'hir> { + /// A `box x` expression. + Box(&'hir Expr<'hir>), + /// Allow anonymous constants from an inline `const` block + ConstBlock(AnonConst), + /// An array (e.g., `[a, b, c, d]`). + Array(&'hir [Expr<'hir>]), + /// A function call. + /// + /// The first field resolves to the function itself (usually an `ExprKind::Path`), + /// and the second field is the list of arguments. + /// This also represents calling the constructor of + /// tuple-like ADTs such as tuple structs and enum variants. + Call(&'hir Expr<'hir>, &'hir [Expr<'hir>]), + /// A method call (e.g., `x.foo::<'static, Bar, Baz>(a, b, c, d)`). + /// + /// The `PathSegment` represents the method name and its generic arguments + /// (within the angle brackets). + /// The first element of the `&[Expr]` is the expression that evaluates + /// to the object on which the method is being called on (the receiver), + /// and the remaining elements are the rest of the arguments. + /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as + /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d], span)`. + /// The final `Span` represents the span of the function and arguments + /// (e.g. `foo::<Bar, Baz>(a, b, c, d)` in `x.foo::<Bar, Baz>(a, b, c, d)` + /// + /// To resolve the called method to a `DefId`, call [`type_dependent_def_id`] with + /// the `hir_id` of the `MethodCall` node itself. + /// + /// [`type_dependent_def_id`]: ../../rustc_middle/ty/struct.TypeckResults.html#method.type_dependent_def_id + MethodCall(&'hir PathSegment<'hir>, &'hir [Expr<'hir>], Span), + /// A tuple (e.g., `(a, b, c, d)`). + Tup(&'hir [Expr<'hir>]), + /// A binary operation (e.g., `a + b`, `a * b`). + Binary(BinOp, &'hir Expr<'hir>, &'hir Expr<'hir>), + /// A unary operation (e.g., `!x`, `*x`). + Unary(UnOp, &'hir Expr<'hir>), + /// A literal (e.g., `1`, `"foo"`). + Lit(Lit), + /// A cast (e.g., `foo as f64`). + Cast(&'hir Expr<'hir>, &'hir Ty<'hir>), + /// A type reference (e.g., `Foo`). + Type(&'hir Expr<'hir>, &'hir Ty<'hir>), + /// Wraps the expression in a terminating scope. + /// This makes it semantically equivalent to `{ let _t = expr; _t }`. + /// + /// This construct only exists to tweak the drop order in HIR lowering. + /// An example of that is the desugaring of `for` loops. + DropTemps(&'hir Expr<'hir>), + /// A `let $pat = $expr` expression. + /// + /// These are not `Local` and only occur as expressions. + /// The `let Some(x) = foo()` in `if let Some(x) = foo()` is an example of `Let(..)`. + Let(&'hir Let<'hir>), + /// An `if` block, with an optional else block. + /// + /// I.e., `if <expr> { <expr> } else { <expr> }`. + If(&'hir Expr<'hir>, &'hir Expr<'hir>, Option<&'hir Expr<'hir>>), + /// A conditionless loop (can be exited with `break`, `continue`, or `return`). + /// + /// I.e., `'label: loop { <block> }`. + /// + /// The `Span` is the loop header (`for x in y`/`while let pat = expr`). + Loop(&'hir Block<'hir>, Option<Label>, LoopSource, Span), + /// A `match` block, with a source that indicates whether or not it is + /// the result of a desugaring, and if so, which kind. + Match(&'hir Expr<'hir>, &'hir [Arm<'hir>], MatchSource), + /// A closure (e.g., `move |a, b, c| {a + b + c}`). + /// + /// The `Span` is the argument block `|...|`. + /// + /// This may also be a generator literal or an `async block` as indicated by the + /// `Option<Movability>`. + Closure(&'hir Closure<'hir>), + /// A block (e.g., `'label: { ... }`). + Block(&'hir Block<'hir>, Option<Label>), + + /// An assignment (e.g., `a = foo()`). + Assign(&'hir Expr<'hir>, &'hir Expr<'hir>, Span), + /// An assignment with an operator. + /// + /// E.g., `a += 1`. + AssignOp(BinOp, &'hir Expr<'hir>, &'hir Expr<'hir>), + /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct or tuple field. + Field(&'hir Expr<'hir>, Ident), + /// An indexing operation (`foo[2]`). + Index(&'hir Expr<'hir>, &'hir Expr<'hir>), + + /// Path to a definition, possibly containing lifetime or type parameters. + Path(QPath<'hir>), + + /// A referencing operation (i.e., `&a` or `&mut a`). + AddrOf(BorrowKind, Mutability, &'hir Expr<'hir>), + /// A `break`, with an optional label to break. + Break(Destination, Option<&'hir Expr<'hir>>), + /// A `continue`, with an optional label. + Continue(Destination), + /// A `return`, with an optional value to be returned. + Ret(Option<&'hir Expr<'hir>>), + + /// Inline assembly (from `asm!`), with its outputs and inputs. + InlineAsm(&'hir InlineAsm<'hir>), + + /// A struct or struct-like variant literal expression. + /// + /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. base}`, + /// where `base` is the `Option<Expr>`. + Struct(&'hir QPath<'hir>, &'hir [ExprField<'hir>], Option<&'hir Expr<'hir>>), + + /// An array literal constructed from one repeated element. + /// + /// E.g., `[1; 5]`. The first expression is the element + /// to be repeated; the second is the number of times to repeat it. + Repeat(&'hir Expr<'hir>, ArrayLen), + + /// A suspension point for generators (i.e., `yield <expr>`). + Yield(&'hir Expr<'hir>, YieldSource), + + /// A placeholder for an expression that wasn't syntactically well formed in some way. + Err, +} + +/// Represents an optionally `Self`-qualified value/type path or associated extension. +/// +/// To resolve the path to a `DefId`, call [`qpath_res`]. +/// +/// [`qpath_res`]: ../../rustc_middle/ty/struct.TypeckResults.html#method.qpath_res +#[derive(Debug, HashStable_Generic)] +pub enum QPath<'hir> { + /// Path to a definition, optionally "fully-qualified" with a `Self` + /// type, if the path points to an associated item in a trait. + /// + /// E.g., an unqualified path like `Clone::clone` has `None` for `Self`, + /// while `<Vec<T> as Clone>::clone` has `Some(Vec<T>)` for `Self`, + /// even though they both have the same two-segment `Clone::clone` `Path`. + Resolved(Option<&'hir Ty<'hir>>, &'hir Path<'hir>), + + /// Type-related paths (e.g., `<T>::default` or `<T>::Output`). + /// Will be resolved by type-checking to an associated item. + /// + /// UFCS source paths can desugar into this, with `Vec::new` turning into + /// `<Vec>::new`, and `T::X::Y::method` into `<<<T>::X>::Y>::method`, + /// the `X` and `Y` nodes each being a `TyKind::Path(QPath::TypeRelative(..))`. + TypeRelative(&'hir Ty<'hir>, &'hir PathSegment<'hir>), + + /// Reference to a `#[lang = "foo"]` item. `HirId` of the inner expr. + LangItem(LangItem, Span, Option<HirId>), +} + +impl<'hir> QPath<'hir> { + /// Returns the span of this `QPath`. + pub fn span(&self) -> Span { + match *self { + QPath::Resolved(_, path) => path.span, + QPath::TypeRelative(qself, ps) => qself.span.to(ps.ident.span), + QPath::LangItem(_, span, _) => span, + } + } + + /// Returns the span of the qself of this `QPath`. For example, `()` in + /// `<() as Trait>::method`. + pub fn qself_span(&self) -> Span { + match *self { + QPath::Resolved(_, path) => path.span, + QPath::TypeRelative(qself, _) => qself.span, + QPath::LangItem(_, span, _) => span, + } + } + + /// Returns the span of the last segment of this `QPath`. For example, `method` in + /// `<() as Trait>::method`. + pub fn last_segment_span(&self) -> Span { + match *self { + QPath::Resolved(_, path) => path.segments.last().unwrap().ident.span, + QPath::TypeRelative(_, segment) => segment.ident.span, + QPath::LangItem(_, span, _) => span, + } + } +} + +/// Hints at the original code for a let statement. +#[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)] +pub enum LocalSource { + /// A `match _ { .. }`. + Normal, + /// When lowering async functions, we create locals within the `async move` so that + /// all parameters are dropped after the future is polled. + /// + /// ```ignore (pseudo-Rust) + /// async fn foo(<pattern> @ x: Type) { + /// async move { + /// let <pattern> = x; + /// } + /// } + /// ``` + AsyncFn, + /// A desugared `<expr>.await`. + AwaitDesugar, + /// A desugared `expr = expr`, where the LHS is a tuple, struct or array. + /// The span is that of the `=` sign. + AssignDesugar(Span), +} + +/// Hints at the original code for a `match _ { .. }`. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Hash, Debug)] +#[derive(HashStable_Generic)] +pub enum MatchSource { + /// A `match _ { .. }`. + Normal, + /// A desugared `for _ in _ { .. }` loop. + ForLoopDesugar, + /// A desugared `?` operator. + TryDesugar, + /// A desugared `<expr>.await`. + AwaitDesugar, +} + +impl MatchSource { + #[inline] + pub const fn name(self) -> &'static str { + use MatchSource::*; + match self { + Normal => "match", + ForLoopDesugar => "for", + TryDesugar => "?", + AwaitDesugar => ".await", + } + } +} + +/// The loop type that yielded an `ExprKind::Loop`. +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum LoopSource { + /// A `loop { .. }` loop. + Loop, + /// A `while _ { .. }` loop. + While, + /// A `for _ in _ { .. }` loop. + ForLoop, +} + +impl LoopSource { + pub fn name(self) -> &'static str { + match self { + LoopSource::Loop => "loop", + LoopSource::While => "while", + LoopSource::ForLoop => "for", + } + } +} + +#[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)] +pub enum LoopIdError { + OutsideLoopScope, + UnlabeledCfInWhileCondition, + UnresolvedLabel, +} + +impl fmt::Display for LoopIdError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(match self { + LoopIdError::OutsideLoopScope => "not inside loop scope", + LoopIdError::UnlabeledCfInWhileCondition => { + "unlabeled control flow (break or continue) in while condition" + } + LoopIdError::UnresolvedLabel => "label not found", + }) + } +} + +#[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)] +pub struct Destination { + // This is `Some(_)` iff there is an explicit user-specified `label + pub label: Option<Label>, + + // These errors are caught and then reported during the diagnostics pass in + // librustc_passes/loops.rs + pub target_id: Result<HirId, LoopIdError>, +} + +/// The yield kind that caused an `ExprKind::Yield`. +#[derive(Copy, Clone, PartialEq, Eq, Debug, Encodable, Decodable, HashStable_Generic)] +pub enum YieldSource { + /// An `<expr>.await`. + Await { expr: Option<HirId> }, + /// A plain `yield`. + Yield, +} + +impl YieldSource { + pub fn is_await(&self) -> bool { + matches!(self, YieldSource::Await { .. }) + } +} + +impl fmt::Display for YieldSource { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(match self { + YieldSource::Await { .. } => "`await`", + YieldSource::Yield => "`yield`", + }) + } +} + +impl From<GeneratorKind> for YieldSource { + fn from(kind: GeneratorKind) -> Self { + match kind { + // Guess based on the kind of the current generator. + GeneratorKind::Gen => Self::Yield, + GeneratorKind::Async(_) => Self::Await { expr: None }, + } + } +} + +// N.B., if you change this, you'll probably want to change the corresponding +// type structure in middle/ty.rs as well. +#[derive(Debug, HashStable_Generic)] +pub struct MutTy<'hir> { + pub ty: &'hir Ty<'hir>, + pub mutbl: Mutability, +} + +/// Represents a function's signature in a trait declaration, +/// trait implementation, or a free function. +#[derive(Debug, HashStable_Generic)] +pub struct FnSig<'hir> { + pub header: FnHeader, + pub decl: &'hir FnDecl<'hir>, + pub span: Span, +} + +// The bodies for items are stored "out of line", in a separate +// hashmap in the `Crate`. Here we just record the hir-id of the item +// so it can fetched later. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)] +pub struct TraitItemId { + pub def_id: LocalDefId, +} + +impl TraitItemId { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } +} + +/// Represents an item declaration within a trait declaration, +/// possibly including a default implementation. A trait item is +/// either required (meaning it doesn't have an implementation, just a +/// signature) or provided (meaning it has a default implementation). +#[derive(Debug, HashStable_Generic)] +pub struct TraitItem<'hir> { + pub ident: Ident, + pub def_id: LocalDefId, + pub generics: &'hir Generics<'hir>, + pub kind: TraitItemKind<'hir>, + pub span: Span, + pub defaultness: Defaultness, +} + +impl TraitItem<'_> { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } + + pub fn trait_item_id(&self) -> TraitItemId { + TraitItemId { def_id: self.def_id } + } +} + +/// Represents a trait method's body (or just argument names). +#[derive(Encodable, Debug, HashStable_Generic)] +pub enum TraitFn<'hir> { + /// No default body in the trait, just a signature. + Required(&'hir [Ident]), + + /// Both signature and body are provided in the trait. + Provided(BodyId), +} + +/// Represents a trait method or associated constant or type +#[derive(Debug, HashStable_Generic)] +pub enum TraitItemKind<'hir> { + /// An associated constant with an optional value (otherwise `impl`s must contain a value). + Const(&'hir Ty<'hir>, Option<BodyId>), + /// An associated function with an optional body. + Fn(FnSig<'hir>, TraitFn<'hir>), + /// An associated type with (possibly empty) bounds and optional concrete + /// type. + Type(GenericBounds<'hir>, Option<&'hir Ty<'hir>>), +} + +// The bodies for items are stored "out of line", in a separate +// hashmap in the `Crate`. Here we just record the hir-id of the item +// so it can fetched later. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)] +pub struct ImplItemId { + pub def_id: LocalDefId, +} + +impl ImplItemId { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } +} + +/// Represents anything within an `impl` block. +#[derive(Debug, HashStable_Generic)] +pub struct ImplItem<'hir> { + pub ident: Ident, + pub def_id: LocalDefId, + pub generics: &'hir Generics<'hir>, + pub kind: ImplItemKind<'hir>, + pub defaultness: Defaultness, + pub span: Span, + pub vis_span: Span, +} + +impl ImplItem<'_> { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } + + pub fn impl_item_id(&self) -> ImplItemId { + ImplItemId { def_id: self.def_id } + } +} + +/// Represents various kinds of content within an `impl`. +#[derive(Debug, HashStable_Generic)] +pub enum ImplItemKind<'hir> { + /// An associated constant of the given type, set to the constant result + /// of the expression. + Const(&'hir Ty<'hir>, BodyId), + /// An associated function implementation with the given signature and body. + Fn(FnSig<'hir>, BodyId), + /// An associated type. + TyAlias(&'hir Ty<'hir>), +} + +// The name of the associated type for `Fn` return types. +pub const FN_OUTPUT_NAME: Symbol = sym::Output; + +/// Bind a type to an associated type (i.e., `A = Foo`). +/// +/// Bindings like `A: Debug` are represented as a special type `A = +/// $::Debug` that is understood by the astconv code. +/// +/// FIXME(alexreg): why have a separate type for the binding case, +/// wouldn't it be better to make the `ty` field an enum like the +/// following? +/// +/// ```ignore (pseudo-rust) +/// enum TypeBindingKind { +/// Equals(...), +/// Binding(...), +/// } +/// ``` +#[derive(Debug, HashStable_Generic)] +pub struct TypeBinding<'hir> { + pub hir_id: HirId, + pub ident: Ident, + pub gen_args: &'hir GenericArgs<'hir>, + pub kind: TypeBindingKind<'hir>, + pub span: Span, +} + +#[derive(Debug, HashStable_Generic)] +pub enum Term<'hir> { + Ty(&'hir Ty<'hir>), + Const(AnonConst), +} + +impl<'hir> From<&'hir Ty<'hir>> for Term<'hir> { + fn from(ty: &'hir Ty<'hir>) -> Self { + Term::Ty(ty) + } +} + +impl<'hir> From<AnonConst> for Term<'hir> { + fn from(c: AnonConst) -> Self { + Term::Const(c) + } +} + +// Represents the two kinds of type bindings. +#[derive(Debug, HashStable_Generic)] +pub enum TypeBindingKind<'hir> { + /// E.g., `Foo<Bar: Send>`. + Constraint { bounds: &'hir [GenericBound<'hir>] }, + /// E.g., `Foo<Bar = ()>`, `Foo<Bar = ()>` + Equality { term: Term<'hir> }, +} + +impl TypeBinding<'_> { + pub fn ty(&self) -> &Ty<'_> { + match self.kind { + TypeBindingKind::Equality { term: Term::Ty(ref ty) } => ty, + _ => panic!("expected equality type binding for parenthesized generic args"), + } + } + pub fn opt_const(&self) -> Option<&'_ AnonConst> { + match self.kind { + TypeBindingKind::Equality { term: Term::Const(ref c) } => Some(c), + _ => None, + } + } +} + +#[derive(Debug)] +pub struct Ty<'hir> { + pub hir_id: HirId, + pub kind: TyKind<'hir>, + pub span: Span, +} + +impl<'hir> Ty<'hir> { + /// Returns `true` if `param_def_id` matches the `bounded_ty` of this predicate. + pub fn as_generic_param(&self) -> Option<(DefId, Ident)> { + let TyKind::Path(QPath::Resolved(None, path)) = self.kind else { + return None; + }; + let [segment] = &path.segments else { + return None; + }; + match path.res { + Res::Def(DefKind::TyParam, def_id) + | Res::SelfTy { trait_: Some(def_id), alias_to: None } => Some((def_id, segment.ident)), + _ => None, + } + } +} + +/// Not represented directly in the AST; referred to by name through a `ty_path`. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Hash, Debug)] +#[derive(HashStable_Generic)] +pub enum PrimTy { + Int(IntTy), + Uint(UintTy), + Float(FloatTy), + Str, + Bool, + Char, +} + +impl PrimTy { + /// All of the primitive types + pub const ALL: [Self; 17] = [ + // any changes here should also be reflected in `PrimTy::from_name` + Self::Int(IntTy::I8), + Self::Int(IntTy::I16), + Self::Int(IntTy::I32), + Self::Int(IntTy::I64), + Self::Int(IntTy::I128), + Self::Int(IntTy::Isize), + Self::Uint(UintTy::U8), + Self::Uint(UintTy::U16), + Self::Uint(UintTy::U32), + Self::Uint(UintTy::U64), + Self::Uint(UintTy::U128), + Self::Uint(UintTy::Usize), + Self::Float(FloatTy::F32), + Self::Float(FloatTy::F64), + Self::Bool, + Self::Char, + Self::Str, + ]; + + /// Like [`PrimTy::name`], but returns a &str instead of a symbol. + /// + /// Used by clippy. + pub fn name_str(self) -> &'static str { + match self { + PrimTy::Int(i) => i.name_str(), + PrimTy::Uint(u) => u.name_str(), + PrimTy::Float(f) => f.name_str(), + PrimTy::Str => "str", + PrimTy::Bool => "bool", + PrimTy::Char => "char", + } + } + + pub fn name(self) -> Symbol { + match self { + PrimTy::Int(i) => i.name(), + PrimTy::Uint(u) => u.name(), + PrimTy::Float(f) => f.name(), + PrimTy::Str => sym::str, + PrimTy::Bool => sym::bool, + PrimTy::Char => sym::char, + } + } + + /// Returns the matching `PrimTy` for a `Symbol` such as "str" or "i32". + /// Returns `None` if no matching type is found. + pub fn from_name(name: Symbol) -> Option<Self> { + let ty = match name { + // any changes here should also be reflected in `PrimTy::ALL` + sym::i8 => Self::Int(IntTy::I8), + sym::i16 => Self::Int(IntTy::I16), + sym::i32 => Self::Int(IntTy::I32), + sym::i64 => Self::Int(IntTy::I64), + sym::i128 => Self::Int(IntTy::I128), + sym::isize => Self::Int(IntTy::Isize), + sym::u8 => Self::Uint(UintTy::U8), + sym::u16 => Self::Uint(UintTy::U16), + sym::u32 => Self::Uint(UintTy::U32), + sym::u64 => Self::Uint(UintTy::U64), + sym::u128 => Self::Uint(UintTy::U128), + sym::usize => Self::Uint(UintTy::Usize), + sym::f32 => Self::Float(FloatTy::F32), + sym::f64 => Self::Float(FloatTy::F64), + sym::bool => Self::Bool, + sym::char => Self::Char, + sym::str => Self::Str, + _ => return None, + }; + Some(ty) + } +} + +#[derive(Debug, HashStable_Generic)] +pub struct BareFnTy<'hir> { + pub unsafety: Unsafety, + pub abi: Abi, + pub generic_params: &'hir [GenericParam<'hir>], + pub decl: &'hir FnDecl<'hir>, + pub param_names: &'hir [Ident], +} + +#[derive(Debug, HashStable_Generic)] +pub struct OpaqueTy<'hir> { + pub generics: &'hir Generics<'hir>, + pub bounds: GenericBounds<'hir>, + pub origin: OpaqueTyOrigin, +} + +/// From whence the opaque type came. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)] +pub enum OpaqueTyOrigin { + /// `-> impl Trait` + FnReturn(LocalDefId), + /// `async fn` + AsyncFn(LocalDefId), + /// type aliases: `type Foo = impl Trait;` + TyAlias, +} + +/// The various kinds of types recognized by the compiler. +#[derive(Debug, HashStable_Generic)] +pub enum TyKind<'hir> { + /// A variable length slice (i.e., `[T]`). + Slice(&'hir Ty<'hir>), + /// A fixed length array (i.e., `[T; n]`). + Array(&'hir Ty<'hir>, ArrayLen), + /// A raw pointer (i.e., `*const T` or `*mut T`). + Ptr(MutTy<'hir>), + /// A reference (i.e., `&'a T` or `&'a mut T`). + Rptr(Lifetime, MutTy<'hir>), + /// A bare function (e.g., `fn(usize) -> bool`). + BareFn(&'hir BareFnTy<'hir>), + /// The never type (`!`). + Never, + /// A tuple (`(A, B, C, D, ...)`). + Tup(&'hir [Ty<'hir>]), + /// A path to a type definition (`module::module::...::Type`), or an + /// associated type (e.g., `<Vec<T> as Trait>::Type` or `<T>::Target`). + /// + /// Type parameters may be stored in each `PathSegment`. + Path(QPath<'hir>), + /// An opaque type definition itself. This is only used for `impl Trait`. + /// + /// The generic argument list contains the lifetimes (and in the future + /// possibly parameters) that are actually bound on the `impl Trait`. + OpaqueDef(ItemId, &'hir [GenericArg<'hir>]), + /// A trait object type `Bound1 + Bound2 + Bound3` + /// where `Bound` is a trait or a lifetime. + TraitObject(&'hir [PolyTraitRef<'hir>], Lifetime, TraitObjectSyntax), + /// Unused for now. + Typeof(AnonConst), + /// `TyKind::Infer` means the type should be inferred instead of it having been + /// specified. This can appear anywhere in a type. + Infer, + /// Placeholder for a type that has failed to be defined. + Err, +} + +#[derive(Debug, HashStable_Generic)] +pub enum InlineAsmOperand<'hir> { + In { + reg: InlineAsmRegOrRegClass, + expr: Expr<'hir>, + }, + Out { + reg: InlineAsmRegOrRegClass, + late: bool, + expr: Option<Expr<'hir>>, + }, + InOut { + reg: InlineAsmRegOrRegClass, + late: bool, + expr: Expr<'hir>, + }, + SplitInOut { + reg: InlineAsmRegOrRegClass, + late: bool, + in_expr: Expr<'hir>, + out_expr: Option<Expr<'hir>>, + }, + Const { + anon_const: AnonConst, + }, + SymFn { + anon_const: AnonConst, + }, + SymStatic { + path: QPath<'hir>, + def_id: DefId, + }, +} + +impl<'hir> InlineAsmOperand<'hir> { + pub fn reg(&self) -> Option<InlineAsmRegOrRegClass> { + match *self { + Self::In { reg, .. } + | Self::Out { reg, .. } + | Self::InOut { reg, .. } + | Self::SplitInOut { reg, .. } => Some(reg), + Self::Const { .. } | Self::SymFn { .. } | Self::SymStatic { .. } => None, + } + } + + pub fn is_clobber(&self) -> bool { + matches!( + self, + InlineAsmOperand::Out { reg: InlineAsmRegOrRegClass::Reg(_), late: _, expr: None } + ) + } +} + +#[derive(Debug, HashStable_Generic)] +pub struct InlineAsm<'hir> { + pub template: &'hir [InlineAsmTemplatePiece], + pub template_strs: &'hir [(Symbol, Option<Symbol>, Span)], + pub operands: &'hir [(InlineAsmOperand<'hir>, Span)], + pub options: InlineAsmOptions, + pub line_spans: &'hir [Span], +} + +/// Represents a parameter in a function header. +#[derive(Debug, HashStable_Generic)] +pub struct Param<'hir> { + pub hir_id: HirId, + pub pat: &'hir Pat<'hir>, + pub ty_span: Span, + pub span: Span, +} + +/// Represents the header (not the body) of a function declaration. +#[derive(Debug, HashStable_Generic)] +pub struct FnDecl<'hir> { + /// The types of the function's parameters. + /// + /// Additional argument data is stored in the function's [body](Body::params). + pub inputs: &'hir [Ty<'hir>], + pub output: FnRetTy<'hir>, + pub c_variadic: bool, + /// Does the function have an implicit self? + pub implicit_self: ImplicitSelfKind, +} + +/// Represents what type of implicit self a function has, if any. +#[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)] +pub enum ImplicitSelfKind { + /// Represents a `fn x(self);`. + Imm, + /// Represents a `fn x(mut self);`. + Mut, + /// Represents a `fn x(&self);`. + ImmRef, + /// Represents a `fn x(&mut self);`. + MutRef, + /// Represents when a function does not have a self argument or + /// when a function has a `self: X` argument. + None, +} + +impl ImplicitSelfKind { + /// Does this represent an implicit self? + pub fn has_implicit_self(&self) -> bool { + !matches!(*self, ImplicitSelfKind::None) + } +} + +#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Encodable, Decodable, Debug)] +#[derive(HashStable_Generic)] +pub enum IsAsync { + Async, + NotAsync, +} + +#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Encodable, Decodable, HashStable_Generic)] +pub enum Defaultness { + Default { has_value: bool }, + Final, +} + +impl Defaultness { + pub fn has_value(&self) -> bool { + match *self { + Defaultness::Default { has_value } => has_value, + Defaultness::Final => true, + } + } + + pub fn is_final(&self) -> bool { + *self == Defaultness::Final + } + + pub fn is_default(&self) -> bool { + matches!(*self, Defaultness::Default { .. }) + } +} + +#[derive(Debug, HashStable_Generic)] +pub enum FnRetTy<'hir> { + /// Return type is not specified. + /// + /// Functions default to `()` and + /// closures default to inference. Span points to where return + /// type would be inserted. + DefaultReturn(Span), + /// Everything else. + Return(&'hir Ty<'hir>), +} + +impl FnRetTy<'_> { + #[inline] + pub fn span(&self) -> Span { + match *self { + Self::DefaultReturn(span) => span, + Self::Return(ref ty) => ty.span, + } + } +} + +/// Represents `for<...>` binder before a closure +#[derive(Copy, Clone, Debug, HashStable_Generic)] +pub enum ClosureBinder { + /// Binder is not specified. + Default, + /// Binder is specified. + /// + /// Span points to the whole `for<...>`. + For { span: Span }, +} + +#[derive(Encodable, Debug, HashStable_Generic)] +pub struct Mod<'hir> { + pub spans: ModSpans, + pub item_ids: &'hir [ItemId], +} + +#[derive(Copy, Clone, Debug, HashStable_Generic, Encodable)] +pub struct ModSpans { + /// A span from the first token past `{` to the last token until `}`. + /// For `mod foo;`, the inner span ranges from the first token + /// to the last token in the external file. + pub inner_span: Span, + pub inject_use_span: Span, +} + +#[derive(Debug, HashStable_Generic)] +pub struct EnumDef<'hir> { + pub variants: &'hir [Variant<'hir>], +} + +#[derive(Debug, HashStable_Generic)] +pub struct Variant<'hir> { + /// Name of the variant. + pub ident: Ident, + /// Id of the variant (not the constructor, see `VariantData::ctor_hir_id()`). + pub id: HirId, + /// Fields and constructor id of the variant. + pub data: VariantData<'hir>, + /// Explicit discriminant (e.g., `Foo = 1`). + pub disr_expr: Option<AnonConst>, + /// Span + pub span: Span, +} + +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum UseKind { + /// One import, e.g., `use foo::bar` or `use foo::bar as baz`. + /// Also produced for each element of a list `use`, e.g. + /// `use foo::{a, b}` lowers to `use foo::a; use foo::b;`. + Single, + + /// Glob import, e.g., `use foo::*`. + Glob, + + /// Degenerate list import, e.g., `use foo::{a, b}` produces + /// an additional `use foo::{}` for performing checks such as + /// unstable feature gating. May be removed in the future. + ListStem, +} + +/// References to traits in impls. +/// +/// `resolve` maps each `TraitRef`'s `ref_id` to its defining trait; that's all +/// that the `ref_id` is for. Note that `ref_id`'s value is not the `HirId` of the +/// trait being referred to but just a unique `HirId` that serves as a key +/// within the resolution map. +#[derive(Clone, Debug, HashStable_Generic)] +pub struct TraitRef<'hir> { + pub path: &'hir Path<'hir>, + // Don't hash the `ref_id`. It is tracked via the thing it is used to access. + #[stable_hasher(ignore)] + pub hir_ref_id: HirId, +} + +impl TraitRef<'_> { + /// Gets the `DefId` of the referenced trait. It _must_ actually be a trait or trait alias. + pub fn trait_def_id(&self) -> Option<DefId> { + match self.path.res { + Res::Def(DefKind::Trait | DefKind::TraitAlias, did) => Some(did), + Res::Err => None, + _ => unreachable!(), + } + } +} + +#[derive(Clone, Debug, HashStable_Generic)] +pub struct PolyTraitRef<'hir> { + /// The `'a` in `for<'a> Foo<&'a T>`. + pub bound_generic_params: &'hir [GenericParam<'hir>], + + /// The `Foo<&'a T>` in `for<'a> Foo<&'a T>`. + pub trait_ref: TraitRef<'hir>, + + pub span: Span, +} + +#[derive(Debug, HashStable_Generic)] +pub struct FieldDef<'hir> { + pub span: Span, + pub vis_span: Span, + pub ident: Ident, + pub hir_id: HirId, + pub ty: &'hir Ty<'hir>, +} + +impl FieldDef<'_> { + // Still necessary in couple of places + pub fn is_positional(&self) -> bool { + let first = self.ident.as_str().as_bytes()[0]; + (b'0'..=b'9').contains(&first) + } +} + +/// Fields and constructor IDs of enum variants and structs. +#[derive(Debug, HashStable_Generic)] +pub enum VariantData<'hir> { + /// A struct variant. + /// + /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`. + Struct(&'hir [FieldDef<'hir>], /* recovered */ bool), + /// A tuple variant. + /// + /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`. + Tuple(&'hir [FieldDef<'hir>], HirId), + /// A unit variant. + /// + /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`. + Unit(HirId), +} + +impl<'hir> VariantData<'hir> { + /// Return the fields of this variant. + pub fn fields(&self) -> &'hir [FieldDef<'hir>] { + match *self { + VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, ..) => fields, + _ => &[], + } + } + + /// Return the `HirId` of this variant's constructor, if it has one. + pub fn ctor_hir_id(&self) -> Option<HirId> { + match *self { + VariantData::Struct(_, _) => None, + VariantData::Tuple(_, hir_id) | VariantData::Unit(hir_id) => Some(hir_id), + } + } +} + +// The bodies for items are stored "out of line", in a separate +// hashmap in the `Crate`. Here we just record the hir-id of the item +// so it can fetched later. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, Hash, HashStable_Generic)] +pub struct ItemId { + pub def_id: LocalDefId, +} + +impl ItemId { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } +} + +/// An item +/// +/// The name might be a dummy name in case of anonymous items +#[derive(Debug, HashStable_Generic)] +pub struct Item<'hir> { + pub ident: Ident, + pub def_id: LocalDefId, + pub kind: ItemKind<'hir>, + pub span: Span, + pub vis_span: Span, +} + +impl Item<'_> { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } + + pub fn item_id(&self) -> ItemId { + ItemId { def_id: self.def_id } + } +} + +#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)] +#[derive(Encodable, Decodable, HashStable_Generic)] +pub enum Unsafety { + Unsafe, + Normal, +} + +impl Unsafety { + pub fn prefix_str(&self) -> &'static str { + match self { + Self::Unsafe => "unsafe ", + Self::Normal => "", + } + } +} + +impl fmt::Display for Unsafety { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(match *self { + Self::Unsafe => "unsafe", + Self::Normal => "normal", + }) + } +} + +#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)] +#[derive(Encodable, Decodable, HashStable_Generic)] +pub enum Constness { + Const, + NotConst, +} + +impl fmt::Display for Constness { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(match *self { + Self::Const => "const", + Self::NotConst => "non-const", + }) + } +} + +#[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)] +pub struct FnHeader { + pub unsafety: Unsafety, + pub constness: Constness, + pub asyncness: IsAsync, + pub abi: Abi, +} + +impl FnHeader { + pub fn is_async(&self) -> bool { + matches!(&self.asyncness, IsAsync::Async) + } + + pub fn is_const(&self) -> bool { + matches!(&self.constness, Constness::Const) + } + + pub fn is_unsafe(&self) -> bool { + matches!(&self.unsafety, Unsafety::Unsafe) + } +} + +#[derive(Debug, HashStable_Generic)] +pub enum ItemKind<'hir> { + /// An `extern crate` item, with optional *original* crate name if the crate was renamed. + /// + /// E.g., `extern crate foo` or `extern crate foo_bar as foo`. + ExternCrate(Option<Symbol>), + + /// `use foo::bar::*;` or `use foo::bar::baz as quux;` + /// + /// or just + /// + /// `use foo::bar::baz;` (with `as baz` implicitly on the right). + Use(&'hir Path<'hir>, UseKind), + + /// A `static` item. + Static(&'hir Ty<'hir>, Mutability, BodyId), + /// A `const` item. + Const(&'hir Ty<'hir>, BodyId), + /// A function declaration. + Fn(FnSig<'hir>, &'hir Generics<'hir>, BodyId), + /// A MBE macro definition (`macro_rules!` or `macro`). + Macro(ast::MacroDef, MacroKind), + /// A module. + Mod(Mod<'hir>), + /// An external module, e.g. `extern { .. }`. + ForeignMod { abi: Abi, items: &'hir [ForeignItemRef] }, + /// Module-level inline assembly (from `global_asm!`). + GlobalAsm(&'hir InlineAsm<'hir>), + /// A type alias, e.g., `type Foo = Bar<u8>`. + TyAlias(&'hir Ty<'hir>, &'hir Generics<'hir>), + /// An opaque `impl Trait` type alias, e.g., `type Foo = impl Bar;`. + OpaqueTy(OpaqueTy<'hir>), + /// An enum definition, e.g., `enum Foo<A, B> {C<A>, D<B>}`. + Enum(EnumDef<'hir>, &'hir Generics<'hir>), + /// A struct definition, e.g., `struct Foo<A> {x: A}`. + Struct(VariantData<'hir>, &'hir Generics<'hir>), + /// A union definition, e.g., `union Foo<A, B> {x: A, y: B}`. + Union(VariantData<'hir>, &'hir Generics<'hir>), + /// A trait definition. + Trait(IsAuto, Unsafety, &'hir Generics<'hir>, GenericBounds<'hir>, &'hir [TraitItemRef]), + /// A trait alias. + TraitAlias(&'hir Generics<'hir>, GenericBounds<'hir>), + + /// An implementation, e.g., `impl<A> Trait for Foo { .. }`. + Impl(&'hir Impl<'hir>), +} + +#[derive(Debug, HashStable_Generic)] +pub struct Impl<'hir> { + pub unsafety: Unsafety, + pub polarity: ImplPolarity, + pub defaultness: Defaultness, + // We do not put a `Span` in `Defaultness` because it breaks foreign crate metadata + // decoding as `Span`s cannot be decoded when a `Session` is not available. + pub defaultness_span: Option<Span>, + pub constness: Constness, + pub generics: &'hir Generics<'hir>, + + /// The trait being implemented, if any. + pub of_trait: Option<TraitRef<'hir>>, + + pub self_ty: &'hir Ty<'hir>, + pub items: &'hir [ImplItemRef], +} + +impl ItemKind<'_> { + pub fn generics(&self) -> Option<&Generics<'_>> { + Some(match *self { + ItemKind::Fn(_, ref generics, _) + | ItemKind::TyAlias(_, ref generics) + | ItemKind::OpaqueTy(OpaqueTy { ref generics, .. }) + | ItemKind::Enum(_, ref generics) + | ItemKind::Struct(_, ref generics) + | ItemKind::Union(_, ref generics) + | ItemKind::Trait(_, _, ref generics, _, _) + | ItemKind::TraitAlias(ref generics, _) + | ItemKind::Impl(Impl { ref generics, .. }) => generics, + _ => return None, + }) + } + + pub fn descr(&self) -> &'static str { + match self { + ItemKind::ExternCrate(..) => "extern crate", + ItemKind::Use(..) => "`use` import", + ItemKind::Static(..) => "static item", + ItemKind::Const(..) => "constant item", + ItemKind::Fn(..) => "function", + ItemKind::Macro(..) => "macro", + ItemKind::Mod(..) => "module", + ItemKind::ForeignMod { .. } => "extern block", + ItemKind::GlobalAsm(..) => "global asm item", + ItemKind::TyAlias(..) => "type alias", + ItemKind::OpaqueTy(..) => "opaque type", + ItemKind::Enum(..) => "enum", + ItemKind::Struct(..) => "struct", + ItemKind::Union(..) => "union", + ItemKind::Trait(..) => "trait", + ItemKind::TraitAlias(..) => "trait alias", + ItemKind::Impl(..) => "implementation", + } + } +} + +/// A reference from an trait to one of its associated items. This +/// contains the item's id, naturally, but also the item's name and +/// some other high-level details (like whether it is an associated +/// type or method, and whether it is public). This allows other +/// passes to find the impl they want without loading the ID (which +/// means fewer edges in the incremental compilation graph). +#[derive(Encodable, Debug, HashStable_Generic)] +pub struct TraitItemRef { + pub id: TraitItemId, + pub ident: Ident, + pub kind: AssocItemKind, + pub span: Span, +} + +/// A reference from an impl to one of its associated items. This +/// contains the item's ID, naturally, but also the item's name and +/// some other high-level details (like whether it is an associated +/// type or method, and whether it is public). This allows other +/// passes to find the impl they want without loading the ID (which +/// means fewer edges in the incremental compilation graph). +#[derive(Debug, HashStable_Generic)] +pub struct ImplItemRef { + pub id: ImplItemId, + pub ident: Ident, + pub kind: AssocItemKind, + pub span: Span, + /// When we are in a trait impl, link to the trait-item's id. + pub trait_item_def_id: Option<DefId>, +} + +#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)] +pub enum AssocItemKind { + Const, + Fn { has_self: bool }, + Type, +} + +// The bodies for items are stored "out of line", in a separate +// hashmap in the `Crate`. Here we just record the hir-id of the item +// so it can fetched later. +#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)] +pub struct ForeignItemId { + pub def_id: LocalDefId, +} + +impl ForeignItemId { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } +} + +/// A reference from a foreign block to one of its items. This +/// contains the item's ID, naturally, but also the item's name and +/// some other high-level details (like whether it is an associated +/// type or method, and whether it is public). This allows other +/// passes to find the impl they want without loading the ID (which +/// means fewer edges in the incremental compilation graph). +#[derive(Debug, HashStable_Generic)] +pub struct ForeignItemRef { + pub id: ForeignItemId, + pub ident: Ident, + pub span: Span, +} + +#[derive(Debug, HashStable_Generic)] +pub struct ForeignItem<'hir> { + pub ident: Ident, + pub kind: ForeignItemKind<'hir>, + pub def_id: LocalDefId, + pub span: Span, + pub vis_span: Span, +} + +impl ForeignItem<'_> { + #[inline] + pub fn hir_id(&self) -> HirId { + // Items are always HIR owners. + HirId::make_owner(self.def_id) + } + + pub fn foreign_item_id(&self) -> ForeignItemId { + ForeignItemId { def_id: self.def_id } + } +} + +/// An item within an `extern` block. +#[derive(Debug, HashStable_Generic)] +pub enum ForeignItemKind<'hir> { + /// A foreign function. + Fn(&'hir FnDecl<'hir>, &'hir [Ident], &'hir Generics<'hir>), + /// A foreign static item (`static ext: u8`). + Static(&'hir Ty<'hir>, Mutability), + /// A foreign type. + Type, +} + +/// A variable captured by a closure. +#[derive(Debug, Copy, Clone, Encodable, HashStable_Generic)] +pub struct Upvar { + // First span where it is accessed (there can be multiple). + pub span: Span, +} + +// The TraitCandidate's import_ids is empty if the trait is defined in the same module, and +// has length > 0 if the trait is found through an chain of imports, starting with the +// import/use statement in the scope where the trait is used. +#[derive(Encodable, Decodable, Clone, Debug, HashStable_Generic)] +pub struct TraitCandidate { + pub def_id: DefId, + pub import_ids: SmallVec<[LocalDefId; 1]>, +} + +#[derive(Copy, Clone, Debug, HashStable_Generic)] +pub enum OwnerNode<'hir> { + Item(&'hir Item<'hir>), + ForeignItem(&'hir ForeignItem<'hir>), + TraitItem(&'hir TraitItem<'hir>), + ImplItem(&'hir ImplItem<'hir>), + Crate(&'hir Mod<'hir>), +} + +impl<'hir> OwnerNode<'hir> { + pub fn ident(&self) -> Option<Ident> { + match self { + OwnerNode::Item(Item { ident, .. }) + | OwnerNode::ForeignItem(ForeignItem { ident, .. }) + | OwnerNode::ImplItem(ImplItem { ident, .. }) + | OwnerNode::TraitItem(TraitItem { ident, .. }) => Some(*ident), + OwnerNode::Crate(..) => None, + } + } + + pub fn span(&self) -> Span { + match self { + OwnerNode::Item(Item { span, .. }) + | OwnerNode::ForeignItem(ForeignItem { span, .. }) + | OwnerNode::ImplItem(ImplItem { span, .. }) + | OwnerNode::TraitItem(TraitItem { span, .. }) => *span, + OwnerNode::Crate(Mod { spans: ModSpans { inner_span, .. }, .. }) => *inner_span, + } + } + + pub fn fn_decl(&self) -> Option<&FnDecl<'hir>> { + match self { + OwnerNode::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. }) + | OwnerNode::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. }) + | OwnerNode::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig.decl), + OwnerNode::ForeignItem(ForeignItem { + kind: ForeignItemKind::Fn(fn_decl, _, _), + .. + }) => Some(fn_decl), + _ => None, + } + } + + pub fn body_id(&self) -> Option<BodyId> { + match self { + OwnerNode::TraitItem(TraitItem { + kind: TraitItemKind::Fn(_, TraitFn::Provided(body_id)), + .. + }) + | OwnerNode::ImplItem(ImplItem { kind: ImplItemKind::Fn(_, body_id), .. }) + | OwnerNode::Item(Item { kind: ItemKind::Fn(.., body_id), .. }) => Some(*body_id), + _ => None, + } + } + + pub fn generics(self) -> Option<&'hir Generics<'hir>> { + Node::generics(self.into()) + } + + pub fn def_id(self) -> LocalDefId { + match self { + OwnerNode::Item(Item { def_id, .. }) + | OwnerNode::TraitItem(TraitItem { def_id, .. }) + | OwnerNode::ImplItem(ImplItem { def_id, .. }) + | OwnerNode::ForeignItem(ForeignItem { def_id, .. }) => *def_id, + OwnerNode::Crate(..) => crate::CRATE_HIR_ID.owner, + } + } + + pub fn expect_item(self) -> &'hir Item<'hir> { + match self { + OwnerNode::Item(n) => n, + _ => panic!(), + } + } + + pub fn expect_foreign_item(self) -> &'hir ForeignItem<'hir> { + match self { + OwnerNode::ForeignItem(n) => n, + _ => panic!(), + } + } + + pub fn expect_impl_item(self) -> &'hir ImplItem<'hir> { + match self { + OwnerNode::ImplItem(n) => n, + _ => panic!(), + } + } + + pub fn expect_trait_item(self) -> &'hir TraitItem<'hir> { + match self { + OwnerNode::TraitItem(n) => n, + _ => panic!(), + } + } +} + +impl<'hir> Into<OwnerNode<'hir>> for &'hir Item<'hir> { + fn into(self) -> OwnerNode<'hir> { + OwnerNode::Item(self) + } +} + +impl<'hir> Into<OwnerNode<'hir>> for &'hir ForeignItem<'hir> { + fn into(self) -> OwnerNode<'hir> { + OwnerNode::ForeignItem(self) + } +} + +impl<'hir> Into<OwnerNode<'hir>> for &'hir ImplItem<'hir> { + fn into(self) -> OwnerNode<'hir> { + OwnerNode::ImplItem(self) + } +} + +impl<'hir> Into<OwnerNode<'hir>> for &'hir TraitItem<'hir> { + fn into(self) -> OwnerNode<'hir> { + OwnerNode::TraitItem(self) + } +} + +impl<'hir> Into<Node<'hir>> for OwnerNode<'hir> { + fn into(self) -> Node<'hir> { + match self { + OwnerNode::Item(n) => Node::Item(n), + OwnerNode::ForeignItem(n) => Node::ForeignItem(n), + OwnerNode::ImplItem(n) => Node::ImplItem(n), + OwnerNode::TraitItem(n) => Node::TraitItem(n), + OwnerNode::Crate(n) => Node::Crate(n), + } + } +} + +#[derive(Copy, Clone, Debug, HashStable_Generic)] +pub enum Node<'hir> { + Param(&'hir Param<'hir>), + Item(&'hir Item<'hir>), + ForeignItem(&'hir ForeignItem<'hir>), + TraitItem(&'hir TraitItem<'hir>), + ImplItem(&'hir ImplItem<'hir>), + Variant(&'hir Variant<'hir>), + Field(&'hir FieldDef<'hir>), + AnonConst(&'hir AnonConst), + Expr(&'hir Expr<'hir>), + Stmt(&'hir Stmt<'hir>), + PathSegment(&'hir PathSegment<'hir>), + Ty(&'hir Ty<'hir>), + TypeBinding(&'hir TypeBinding<'hir>), + TraitRef(&'hir TraitRef<'hir>), + Pat(&'hir Pat<'hir>), + Arm(&'hir Arm<'hir>), + Block(&'hir Block<'hir>), + Local(&'hir Local<'hir>), + + /// `Ctor` refers to the constructor of an enum variant or struct. Only tuple or unit variants + /// with synthesized constructors. + Ctor(&'hir VariantData<'hir>), + + Lifetime(&'hir Lifetime), + GenericParam(&'hir GenericParam<'hir>), + + Crate(&'hir Mod<'hir>), + + Infer(&'hir InferArg), +} + +impl<'hir> Node<'hir> { + /// Get the identifier of this `Node`, if applicable. + /// + /// # Edge cases + /// + /// Calling `.ident()` on a [`Node::Ctor`] will return `None` + /// because `Ctor`s do not have identifiers themselves. + /// Instead, call `.ident()` on the parent struct/variant, like so: + /// + /// ```ignore (illustrative) + /// ctor + /// .ctor_hir_id() + /// .and_then(|ctor_id| tcx.hir().find(tcx.hir().get_parent_node(ctor_id))) + /// .and_then(|parent| parent.ident()) + /// ``` + pub fn ident(&self) -> Option<Ident> { + match self { + Node::TraitItem(TraitItem { ident, .. }) + | Node::ImplItem(ImplItem { ident, .. }) + | Node::ForeignItem(ForeignItem { ident, .. }) + | Node::Field(FieldDef { ident, .. }) + | Node::Variant(Variant { ident, .. }) + | Node::Item(Item { ident, .. }) + | Node::PathSegment(PathSegment { ident, .. }) => Some(*ident), + Node::Lifetime(lt) => Some(lt.name.ident()), + Node::GenericParam(p) => Some(p.name.ident()), + Node::TypeBinding(b) => Some(b.ident), + Node::Param(..) + | Node::AnonConst(..) + | Node::Expr(..) + | Node::Stmt(..) + | Node::Block(..) + | Node::Ctor(..) + | Node::Pat(..) + | Node::Arm(..) + | Node::Local(..) + | Node::Crate(..) + | Node::Ty(..) + | Node::TraitRef(..) + | Node::Infer(..) => None, + } + } + + pub fn fn_decl(&self) -> Option<&'hir FnDecl<'hir>> { + match self { + Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. }) + | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. }) + | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig.decl), + Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_decl, _, _), .. }) => { + Some(fn_decl) + } + _ => None, + } + } + + pub fn fn_sig(&self) -> Option<&'hir FnSig<'hir>> { + match self { + Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. }) + | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. }) + | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig), + _ => None, + } + } + + pub fn body_id(&self) -> Option<BodyId> { + match self { + Node::TraitItem(TraitItem { + kind: TraitItemKind::Fn(_, TraitFn::Provided(body_id)), + .. + }) + | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(_, body_id), .. }) + | Node::Item(Item { kind: ItemKind::Fn(.., body_id), .. }) => Some(*body_id), + _ => None, + } + } + + pub fn generics(self) -> Option<&'hir Generics<'hir>> { + match self { + Node::ForeignItem(ForeignItem { + kind: ForeignItemKind::Fn(_, _, generics), .. + }) + | Node::TraitItem(TraitItem { generics, .. }) + | Node::ImplItem(ImplItem { generics, .. }) => Some(generics), + Node::Item(item) => item.kind.generics(), + _ => None, + } + } + + pub fn as_owner(self) -> Option<OwnerNode<'hir>> { + match self { + Node::Item(i) => Some(OwnerNode::Item(i)), + Node::ForeignItem(i) => Some(OwnerNode::ForeignItem(i)), + Node::TraitItem(i) => Some(OwnerNode::TraitItem(i)), + Node::ImplItem(i) => Some(OwnerNode::ImplItem(i)), + Node::Crate(i) => Some(OwnerNode::Crate(i)), + _ => None, + } + } + + pub fn fn_kind(self) -> Option<FnKind<'hir>> { + match self { + Node::Item(i) => match i.kind { + ItemKind::Fn(ref sig, ref generics, _) => { + Some(FnKind::ItemFn(i.ident, generics, sig.header)) + } + _ => None, + }, + Node::TraitItem(ti) => match ti.kind { + TraitItemKind::Fn(ref sig, TraitFn::Provided(_)) => { + Some(FnKind::Method(ti.ident, sig)) + } + _ => None, + }, + Node::ImplItem(ii) => match ii.kind { + ImplItemKind::Fn(ref sig, _) => Some(FnKind::Method(ii.ident, sig)), + _ => None, + }, + Node::Expr(e) => match e.kind { + ExprKind::Closure { .. } => Some(FnKind::Closure), + _ => None, + }, + _ => None, + } + } + + /// Get the fields for the tuple-constructor, + /// if this node is a tuple constructor, otherwise None + pub fn tuple_fields(&self) -> Option<&'hir [FieldDef<'hir>]> { + if let Node::Ctor(&VariantData::Tuple(fields, _)) = self { Some(fields) } else { None } + } +} + +// Some nodes are used a lot. Make sure they don't unintentionally get bigger. +#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] +mod size_asserts { + use super::*; + // These are in alphabetical order, which is easy to maintain. + rustc_data_structures::static_assert_size!(Block<'static>, 48); + rustc_data_structures::static_assert_size!(Expr<'static>, 56); + rustc_data_structures::static_assert_size!(ForeignItem<'static>, 72); + rustc_data_structures::static_assert_size!(GenericBound<'_>, 48); + rustc_data_structures::static_assert_size!(Generics<'static>, 56); + rustc_data_structures::static_assert_size!(ImplItem<'static>, 88); + rustc_data_structures::static_assert_size!(Impl<'static>, 80); + rustc_data_structures::static_assert_size!(Item<'static>, 80); + rustc_data_structures::static_assert_size!(Pat<'static>, 88); + rustc_data_structures::static_assert_size!(QPath<'static>, 24); + rustc_data_structures::static_assert_size!(TraitItem<'static>, 96); + rustc_data_structures::static_assert_size!(Ty<'static>, 72); +} |