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fuchsia / third_party / rust / 3f97c6be8d4b78c9df55804171c588ebfadcb63e / . / compiler / rustc_hir / src / hir.rs
blob: 51e637b5748582f0e8a0679c1f69d72804d90795 [file] [log] [blame]
use std::fmt;
use rustc_abi::ExternAbi;
use rustc_ast::util::parser::{AssocOp, ExprPrecedence};
use rustc_ast::{
self as ast, Attribute, FloatTy, InlineAsmOptions, InlineAsmTemplatePiece, IntTy, Label,
LitKind, TraitObjectSyntax, UintTy,
};
pub use rustc_ast::{
BinOp, BinOpKind, BindingMode, BorrowKind, BoundConstness, BoundPolarity, ByRef, CaptureBy,
ImplPolarity, IsAuto, Movability, Mutability, UnOp, UnsafeBinderCastKind,
};
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::sorted_map::SortedMap;
use rustc_index::IndexVec;
use rustc_macros::{Decodable, Encodable, HashStable_Generic};
use rustc_span::def_id::LocalDefId;
use rustc_span::hygiene::MacroKind;
use rustc_span::source_map::Spanned;
use rustc_span::symbol::{Ident, Symbol, kw, sym};
use rustc_span::{BytePos, DUMMY_SP, ErrorGuaranteed, Span};
use rustc_target::asm::InlineAsmRegOrRegClass;
use smallvec::SmallVec;
use tracing::debug;
use crate::LangItem;
use crate::def::{CtorKind, DefKind, Res};
use crate::def_id::{DefId, LocalDefIdMap};
pub(crate) use crate::hir_id::{HirId, ItemLocalId, ItemLocalMap, OwnerId};
use crate::intravisit::FnKind;
#[derive(Debug, Copy, Clone, HashStable_Generic)]
pub struct Lifetime {
pub hir_id: HirId,
/// Either "`'a`", referring to a named lifetime definition,
/// `'_` referring to an anonymous lifetime (either explicitly `'_` or `&type`),
/// or "``" (i.e., `kw::Empty`) when appearing in path.
///
/// See `Lifetime::suggestion_position` for practical use.
pub ident: Ident,
/// Semantics of this lifetime.
pub res: LifetimeName,
}
#[derive(Debug, Copy, Clone, 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),
}
}
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, HashStable_Generic)]
pub enum LifetimeName {
/// User-given names or fresh (synthetic) names.
Param(LocalDefId),
/// 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 {
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,
}
}
}
impl fmt::Display for Lifetime {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if self.ident.name != kw::Empty { self.ident.name.fmt(f) } else { "'_".fmt(f) }
}
}
pub enum LifetimeSuggestionPosition {
/// The user wrote `'a` or `'_`.
Normal,
/// The user wrote `&type` or `&mut type`.
Ampersand,
/// The user wrote `Path` and omitted the `<'_>`.
ElidedPath,
/// The user wrote `Path<T>`, and omitted the `'_,`.
ElidedPathArgument,
/// The user wrote `dyn Trait` and omitted the `+ '_`.
ObjectDefault,
}
impl Lifetime {
pub fn is_elided(&self) -> bool {
self.res.is_elided()
}
pub fn is_anonymous(&self) -> bool {
self.ident.name == kw::Empty || self.ident.name == kw::UnderscoreLifetime
}
pub fn suggestion_position(&self) -> (LifetimeSuggestionPosition, Span) {
if self.ident.name == kw::Empty {
if self.ident.span.is_empty() {
(LifetimeSuggestionPosition::ElidedPathArgument, self.ident.span)
} else {
(LifetimeSuggestionPosition::ElidedPath, self.ident.span.shrink_to_hi())
}
} else if self.res == LifetimeName::ImplicitObjectLifetimeDefault {
(LifetimeSuggestionPosition::ObjectDefault, self.ident.span)
} else if self.ident.span.is_empty() {
(LifetimeSuggestionPosition::Ampersand, self.ident.span)
} else {
(LifetimeSuggestionPosition::Normal, self.ident.span)
}
}
pub fn suggestion(&self, new_lifetime: &str) -> (Span, String) {
debug_assert!(new_lifetime.starts_with('\''));
let (pos, span) = self.suggestion_position();
let code = match pos {
LifetimeSuggestionPosition::Normal => format!("{new_lifetime}"),
LifetimeSuggestionPosition::Ampersand => format!("{new_lifetime} "),
LifetimeSuggestionPosition::ElidedPath => format!("<{new_lifetime}>"),
LifetimeSuggestionPosition::ElidedPathArgument => format!("{new_lifetime}, "),
LifetimeSuggestionPosition::ObjectDefault => format!("+ {new_lifetime}"),
};
(span, code)
}
}
/// 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, Clone, Copy, HashStable_Generic)]
pub struct Path<'hir, R = Res> {
pub span: Span,
/// The resolution for the path.
pub res: R,
/// The segments in the path: the things separated by `::`.
pub segments: &'hir [PathSegment<'hir>],
}
/// Up to three resolutions for type, value and macro namespaces.
pub type UsePath<'hir> = Path<'hir, SmallVec<[Res; 3]>>;
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, Clone, Copy, HashStable_Generic)]
pub struct PathSegment<'hir> {
/// The identifier portion of this path segment.
pub ident: Ident,
pub hir_id: HirId,
pub res: 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 new(ident: Ident, hir_id: HirId, res: Res) -> PathSegment<'hir> {
PathSegment { ident, hir_id, res, infer_args: true, args: None }
}
pub fn invalid() -> Self {
Self::new(Ident::empty(), HirId::INVALID, Res::Err)
}
pub fn args(&self) -> &GenericArgs<'hir> {
if let Some(ref args) = self.args {
args
} else {
const DUMMY: &GenericArgs<'_> = &GenericArgs::none();
DUMMY
}
}
}
/// A constant that enters the type system, used for arguments to const generics (e.g. array lengths).
///
/// These are distinct from [`AnonConst`] as anon consts in the type system are not allowed
/// to use any generic parameters, therefore we must represent `N` differently. Additionally
/// future designs for supporting generic parameters in const arguments will likely not use
/// an anon const based design.
///
/// So, `ConstArg` (specifically, [`ConstArgKind`]) distinguishes between const args
/// that are [just paths](ConstArgKind::Path) (currently just bare const params)
/// versus const args that are literals or have arbitrary computations (e.g., `{ 1 + 3 }`).
#[derive(Clone, Copy, Debug, HashStable_Generic)]
pub struct ConstArg<'hir> {
#[stable_hasher(ignore)]
pub hir_id: HirId,
pub kind: ConstArgKind<'hir>,
}
impl<'hir> ConstArg<'hir> {
pub fn anon_const_hir_id(&self) -> Option<HirId> {
match self.kind {
ConstArgKind::Anon(ac) => Some(ac.hir_id),
_ => None,
}
}
pub fn span(&self) -> Span {
match self.kind {
ConstArgKind::Path(path) => path.span(),
ConstArgKind::Anon(anon) => anon.span,
ConstArgKind::Infer(span) => span,
}
}
}
/// See [`ConstArg`].
#[derive(Clone, Copy, Debug, HashStable_Generic)]
pub enum ConstArgKind<'hir> {
/// **Note:** Currently this is only used for bare const params
/// (`N` where `fn foo<const N: usize>(...)`),
/// not paths to any const (`N` where `const N: usize = ...`).
///
/// However, in the future, we'll be using it for all of those.
Path(QPath<'hir>),
Anon(&'hir AnonConst),
/// **Note:** Not all inferred consts are represented as
/// `ConstArgKind::Infer`. In cases where it is ambiguous whether
/// a generic arg is a type or a const, inference variables are
/// represented as `GenericArg::Infer` instead.
Infer(Span),
}
#[derive(Clone, Copy, Debug, HashStable_Generic)]
pub struct InferArg {
pub hir_id: HirId,
pub span: Span,
}
impl InferArg {
pub fn to_ty(&self) -> Ty<'static> {
Ty { kind: TyKind::Infer, span: self.span, hir_id: self.hir_id }
}
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum GenericArg<'hir> {
Lifetime(&'hir Lifetime),
Type(&'hir Ty<'hir>),
Const(&'hir ConstArg<'hir>),
/// **Note:** Inference variables are only represented as
/// `GenericArg::Infer` in cases where it is ambiguous whether
/// a generic arg is a type or a const. Otherwise, inference variables
/// are represented as `TyKind::Infer` or `ConstArgKind::Infer`.
Infer(InferArg),
}
impl GenericArg<'_> {
pub fn span(&self) -> Span {
match self {
GenericArg::Lifetime(l) => l.ident.span,
GenericArg::Type(t) => t.span,
GenericArg::Const(c) => c.span(),
GenericArg::Infer(i) => i.span,
}
}
pub fn hir_id(&self) -> HirId {
match self {
GenericArg::Lifetime(l) => l.hir_id,
GenericArg::Type(t) => t.hir_id,
GenericArg::Const(c) => c.hir_id,
GenericArg::Infer(i) => i.hir_id,
}
}
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(_) | GenericArg::Const(_) | GenericArg::Infer(_) => {
ast::ParamKindOrd::TypeOrConst
}
}
}
pub fn is_ty_or_const(&self) -> bool {
match self {
GenericArg::Lifetime(_) => false,
GenericArg::Type(_) | GenericArg::Const(_) | GenericArg::Infer(_) => true,
}
}
}
/// The generic arguments and associated item constraints of a path segment.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct GenericArgs<'hir> {
/// The generic arguments for this path segment.
pub args: &'hir [GenericArg<'hir>],
/// The associated item constraints for this path segment.
pub constraints: &'hir [AssocItemConstraint<'hir>],
/// Whether the arguments were written in parenthesized form (e.g., `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: GenericArgsParentheses,
/// The span encompassing the arguments, constraints and the surrounding brackets (`<>` or `()`).
///
/// For example:
///
/// ```ignore (illustrative)
/// 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 during desugaring
pub span_ext: Span,
}
impl<'hir> GenericArgs<'hir> {
pub const fn none() -> Self {
Self {
args: &[],
constraints: &[],
parenthesized: GenericArgsParentheses::No,
span_ext: DUMMY_SP,
}
}
/// Obtain the list of input types and the output type if the generic arguments are parenthesized.
///
/// Returns the `Ty0, Ty1, ...` and the `RetTy` in `Trait(Ty0, Ty1, ...) -> RetTy`.
/// Panics if the parenthesized arguments have an incorrect form (this shouldn't happen).
pub fn paren_sugar_inputs_output(&self) -> Option<(&[Ty<'hir>], &Ty<'hir>)> {
if self.parenthesized != GenericArgsParentheses::ParenSugar {
return None;
}
let inputs = self
.args
.iter()
.find_map(|arg| {
let GenericArg::Type(ty) = arg else { return None };
let TyKind::Tup(tys) = &ty.kind else { return None };
Some(tys)
})
.unwrap();
Some((inputs, self.paren_sugar_output_inner()))
}
/// Obtain the output type if the generic arguments are parenthesized.
///
/// Returns the `RetTy` in `Trait(Ty0, Ty1, ...) -> RetTy`.
/// Panics if the parenthesized arguments have an incorrect form (this shouldn't happen).
pub fn paren_sugar_output(&self) -> Option<&Ty<'hir>> {
(self.parenthesized == GenericArgsParentheses::ParenSugar)
.then(|| self.paren_sugar_output_inner())
}
fn paren_sugar_output_inner(&self) -> &Ty<'hir> {
let [constraint] = self.constraints.try_into().unwrap();
debug_assert_eq!(constraint.ident.name, sym::Output);
constraint.ty().unwrap()
}
pub fn has_err(&self) -> Option<ErrorGuaranteed> {
self.args
.iter()
.find_map(|arg| {
let GenericArg::Type(ty) = arg else { return None };
let TyKind::Err(guar) = ty.kind else { return None };
Some(guar)
})
.or_else(|| {
self.constraints.iter().find_map(|constraint| {
let TyKind::Err(guar) = constraint.ty()?.kind else { return None };
Some(guar)
})
})
}
#[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]
/// This function returns the number of type and const generic params.
/// It should only be used for diagnostics.
pub fn num_generic_params(&self) -> usize {
self.args.iter().filter(|arg| !matches!(arg, GenericArg::Lifetime(_))).count()
}
/// The span encompassing the arguments and constraints[^1] inside the surrounding brackets.
///
/// Returns `None` if the span is empty (i.e., no brackets) or dummy.
///
/// [^1]: Unless of the form `-> Ty` (see [`GenericArgsParentheses`]).
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()
}
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, HashStable_Generic)]
pub enum GenericArgsParentheses {
No,
/// Bounds for `feature(return_type_notation)`, like `T: Trait<method(..): Send>`,
/// where the args are explicitly elided with `..`
ReturnTypeNotation,
/// parenthesized function-family traits, like `T: Fn(u32) -> i32`
ParenSugar,
}
/// The modifiers on a trait bound.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable_Generic)]
pub struct TraitBoundModifiers {
pub constness: BoundConstness,
pub polarity: BoundPolarity,
}
impl TraitBoundModifiers {
pub const NONE: Self =
TraitBoundModifiers { constness: BoundConstness::Never, polarity: BoundPolarity::Positive };
}
#[derive(Clone, Copy, Debug, HashStable_Generic)]
pub enum GenericBound<'hir> {
Trait(PolyTraitRef<'hir>),
Outlives(&'hir Lifetime),
Use(&'hir [PreciseCapturingArg<'hir>], Span),
}
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::Outlives(l) => l.ident.span,
GenericBound::Use(_, span) => *span,
}
}
}
pub type GenericBounds<'hir> = &'hir [GenericBound<'hir>];
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable_Generic, Debug)]
pub enum MissingLifetimeKind {
/// An explicit `'_`.
Underscore,
/// An elided lifetime `&' ty`.
Ampersand,
/// An elided lifetime in brackets with written brackets.
Comma,
/// An elided lifetime with elided brackets.
Brackets,
}
#[derive(Copy, Clone, 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(MissingLifetimeKind),
// Indication that the lifetime name was somehow in error.
Error,
}
#[derive(Debug, Clone, Copy, 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<&'hir ConstArg<'hir>>,
synthetic: bool,
},
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct GenericParam<'hir> {
pub hir_id: HirId,
pub def_id: LocalDefId,
pub name: ParamName,
pub span: Span,
pub pure_wrt_drop: bool,
pub kind: GenericParamKind<'hir>,
pub colon_span: Option<Span>,
pub source: GenericParamSource,
}
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(_) })
}
}
/// Records where the generic parameter originated from.
///
/// This can either be from an item's generics, in which case it's typically
/// early-bound (but can be a late-bound lifetime in functions, for example),
/// or from a `for<...>` binder, in which case it's late-bound (and notably,
/// does not show up in the parent item's generics).
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum GenericParamSource {
// Early or late-bound parameters defined on an item
Generics,
// Late-bound parameters defined via a `for<...>`
Binder,
}
#[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, Clone, Copy, 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>> {
self.params.iter().find(|&param| name == param.name.ident().name)
}
/// If there are generic parameters, return where to introduce a new one.
pub fn span_for_lifetime_suggestion(&self) -> Option<Span> {
if let Some(first) = self.params.first()
&& self.span.contains(first.span)
{
// `fn foo<A>(t: impl Trait)`
// ^ suggest `'a, ` here
Some(first.span.shrink_to_lo())
} else {
None
}
}
/// If there are generic parameters, return where to introduce a new one.
pub fn span_for_param_suggestion(&self) -> Option<Span> {
self.params.iter().any(|p| self.span.contains(p.span)).then(|| {
// `fn foo<A>(t: impl Trait)`
// ^ suggest `, T: Trait` here
self.span.with_lo(self.span.hi() - BytePos(1)).shrink_to_lo()
})
}
/// `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()
.rfind(|&p| p.kind.in_where_clause())
.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.kind {
WherePredicateKind::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.kind {
WherePredicateKind::RegionPredicate(rp) if rp.is_param_bound(param_def_id) => Some(rp),
_ => None,
})
}
/// Returns a suggestable empty span right after the "final" bound of the generic parameter.
///
/// If that bound needs to be wrapped in parentheses to avoid ambiguity with
/// subsequent bounds, it also returns an empty span for an open parenthesis
/// as the second component.
///
/// E.g., adding `+ 'static` after `Fn() -> dyn Future<Output = ()>` or
/// `Fn() -> &'static dyn Debug` requires parentheses:
/// `Fn() -> (dyn Future<Output = ()>) + 'static` and
/// `Fn() -> &'static (dyn Debug) + 'static`, respectively.
pub fn bounds_span_for_suggestions(
&self,
param_def_id: LocalDefId,
) -> Option<(Span, Option<Span>)> {
self.bounds_for_param(param_def_id).flat_map(|bp| bp.bounds.iter().rev()).find_map(
|bound| {
let span_for_parentheses = if let Some(trait_ref) = bound.trait_ref()
&& let [.., segment] = trait_ref.path.segments
&& let Some(ret_ty) = segment.args().paren_sugar_output()
&& let ret_ty = ret_ty.peel_refs()
&& let TyKind::TraitObject(
_,
_,
TraitObjectSyntax::Dyn | TraitObjectSyntax::DynStar,
) = ret_ty.kind
&& ret_ty.span.can_be_used_for_suggestions()
{
Some(ret_ty.span)
} else {
None
};
span_for_parentheses.map_or_else(
|| {
// 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();
bs.can_be_used_for_suggestions().then(|| (bs.shrink_to_hi(), None))
},
|span| Some((span.shrink_to_hi(), Some(span.shrink_to_lo()))),
)
},
)
}
pub fn span_for_predicate_removal(&self, pos: usize) -> Span {
let predicate = &self.predicates[pos];
let span = predicate.span;
if !predicate.kind.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.kind.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.kind.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.kind.bounds();
if bounds.len() == 1 {
return self.span_for_predicate_removal(predicate_pos);
}
let bound_span = bounds[bound_pos].span();
if bound_pos < bounds.len() - 1 {
// If there's another bound after the current bound
// include the following '+' e.g.:
//
// `T: Foo + CurrentBound + Bar`
// ^^^^^^^^^^^^^^^
bound_span.to(bounds[bound_pos + 1].span().shrink_to_lo())
} else {
// If the current bound is the last bound
// include the preceding '+' E.g.:
//
// `T: Foo + Bar + CurrentBound`
// ^^^^^^^^^^^^^^^
bound_span.with_lo(bounds[bound_pos - 1].span().hi())
}
}
}
/// A single predicate in a where-clause.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct WherePredicate<'hir> {
pub hir_id: HirId,
pub span: Span,
pub kind: &'hir WherePredicateKind<'hir>,
}
/// The kind of a single predicate in a where-clause.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum WherePredicateKind<'hir> {
/// A type bound (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> WherePredicateKind<'hir> {
pub fn in_where_clause(&self) -> bool {
match self {
WherePredicateKind::BoundPredicate(p) => p.origin == PredicateOrigin::WhereClause,
WherePredicateKind::RegionPredicate(p) => p.in_where_clause,
WherePredicateKind::EqPredicate(_) => false,
}
}
pub fn bounds(&self) -> GenericBounds<'hir> {
match self {
WherePredicateKind::BoundPredicate(p) => p.bounds,
WherePredicateKind::RegionPredicate(p) => p.bounds,
WherePredicateKind::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, Clone, Copy, HashStable_Generic)]
pub struct WhereBoundPredicate<'hir> {
/// 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().is_some_and(|(def_id, _)| def_id == param_def_id)
}
}
/// A lifetime predicate (e.g., `'a: 'b + 'c`).
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct WhereRegionPredicate<'hir> {
pub in_where_clause: bool,
pub lifetime: &'hir Lifetime,
pub bounds: GenericBounds<'hir>,
}
impl<'hir> WhereRegionPredicate<'hir> {
/// Returns `true` if `param_def_id` matches the `lifetime` of this predicate.
fn is_param_bound(&self, param_def_id: LocalDefId) -> bool {
self.lifetime.res == LifetimeName::Param(param_def_id)
}
}
/// An equality predicate (e.g., `T = int`); currently unsupported.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct WhereEqPredicate<'hir> {
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, Copy, 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]>,
// Only present when the crate hash is needed.
pub opt_hash: Option<Fingerprint>,
}
impl<'tcx> AttributeMap<'tcx> {
pub const EMPTY: &'static AttributeMap<'static> =
&AttributeMap { map: SortedMap::new(), opt_hash: Some(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. Used in the crate hash. Only present
/// when incr. comp. is enabled.
pub opt_hash_including_bodies: Option<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, ParentedNode<'tcx>>,
/// Content of local bodies.
pub bodies: SortedMap<ItemLocalId, &'tcx Body<'tcx>>,
}
impl<'tcx> OwnerNodes<'tcx> {
pub fn node(&self) -> OwnerNode<'tcx> {
// Indexing must ensure it is an OwnerNode.
self.nodes[ItemLocalId::ZERO].node.as_owner().unwrap()
}
}
impl fmt::Debug for OwnerNodes<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("OwnerNodes")
// Do not print all the pointers to all the nodes, as it would be unreadable.
.field("node", &self.nodes[ItemLocalId::ZERO])
.field(
"parents",
&self
.nodes
.iter_enumerated()
.map(|(id, parented_node)| {
debug_fn(move |f| write!(f, "({id:?}, {:?})", parented_node.parent))
})
.collect::<Vec<_>>(),
)
.field("bodies", &self.bodies)
.field("opt_hash_including_bodies", &self.opt_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: LocalDefIdMap<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: ItemLocalMap<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<'tcx> {
Owner(&'tcx OwnerInfo<'tcx>),
NonOwner(HirId),
/// Used as a placeholder for unused LocalDefId.
Phantom,
}
impl<'tcx> MaybeOwner<'tcx> {
pub fn as_owner(self) -> Option<&'tcx OwnerInfo<'tcx>> {
match self {
MaybeOwner::Owner(i) => Some(i),
MaybeOwner::NonOwner(_) | MaybeOwner::Phantom => None,
}
}
pub fn unwrap(self) -> &'tcx OwnerInfo<'tcx> {
self.as_owner().unwrap_or_else(|| 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>>,
// Only present when incr. comp. is enabled.
pub opt_hir_hash: Option<Fingerprint>,
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct Closure<'hir> {
pub def_id: LocalDefId,
pub binder: ClosureBinder,
pub constness: Constness,
pub capture_clause: CaptureBy,
pub bound_generic_params: &'hir [GenericParam<'hir>],
pub fn_decl: &'hir FnDecl<'hir>,
pub body: BodyId,
/// The span of the declaration block: 'move |...| -> ...'
pub fn_decl_span: Span,
/// The span of the argument block `|...|`
pub fn_arg_span: Option<Span>,
pub kind: ClosureKind,
}
#[derive(Clone, PartialEq, Eq, Debug, Copy, Hash, HashStable_Generic, Encodable, Decodable)]
pub enum ClosureKind {
/// This is a plain closure expression.
Closure,
/// This is a coroutine expression -- i.e. a closure expression in which
/// we've found a `yield`. These can arise either from "plain" coroutine
/// usage (e.g. `let x = || { yield (); }`) or from a desugared expression
/// (e.g. `async` and `gen` blocks).
Coroutine(CoroutineKind),
/// This is a coroutine-closure, which is a special sugared closure that
/// returns one of the sugared coroutine (`async`/`gen`/`async gen`). It
/// additionally allows capturing the coroutine's upvars by ref, and therefore
/// needs to be specially treated during analysis and borrowck.
CoroutineClosure(CoroutineDesugaring),
}
/// 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, Clone, Copy, 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,
/// The span includes the curly braces `{` and `}` around the block.
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, Clone, Copy, 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> {
fn walk_short_(&self, it: &mut impl FnMut(&Pat<'hir>) -> bool) -> bool {
if !it(self) {
return false;
}
use PatKind::*;
match self.kind {
Wild | Never | Lit(_) | Range(..) | Binding(.., None) | Path(_) | Err(_) => true,
Box(s) | Deref(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)
}
fn walk_(&self, it: &mut impl FnMut(&Pat<'hir>) -> bool) {
if !it(self) {
return;
}
use PatKind::*;
match self.kind {
Wild | Never | Lit(_) | Range(..) | Binding(.., None) | Path(_) | Err(_) => {}
Box(s) | Deref(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
})
}
/// Whether this a never pattern.
pub fn is_never_pattern(&self) -> bool {
let mut is_never_pattern = false;
self.walk(|pat| match &pat.kind {
PatKind::Never => {
is_never_pattern = true;
false
}
PatKind::Or(s) => {
is_never_pattern = s.iter().all(|p| p.is_never_pattern());
false
}
_ => true,
});
is_never_pattern
}
}
/// 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, Clone, Copy, 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,
}
#[derive(Copy, Clone, PartialEq, 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 => "..",
})
}
}
// Equivalent to `Option<usize>`. That type takes up 16 bytes on 64-bit, but
// this type only takes up 4 bytes, at the cost of being restricted to a
// maximum value of `u32::MAX - 1`. In practice, this is more than enough.
#[derive(Clone, Copy, PartialEq, Eq, Hash, HashStable_Generic)]
pub struct DotDotPos(u32);
impl DotDotPos {
/// Panics if n >= u32::MAX.
pub fn new(n: Option<usize>) -> Self {
match n {
Some(n) => {
assert!(n < u32::MAX as usize);
Self(n as u32)
}
None => Self(u32::MAX),
}
}
pub fn as_opt_usize(&self) -> Option<usize> {
if self.0 == u32::MAX { None } else { Some(self.0 as usize) }
}
}
impl fmt::Debug for DotDotPos {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.as_opt_usize().fmt(f)
}
}
#[derive(Debug, Clone, Copy, 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(BindingMode, 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 `DotDotPos` denotes its position.
/// `0 <= position <= subpats.len()`
TupleStruct(QPath<'hir>, &'hir [Pat<'hir>], DotDotPos),
/// An or-pattern `A | B | C`.
/// Invariant: `pats.len() >= 2`.
Or(&'hir [Pat<'hir>]),
/// A never pattern `!`.
Never,
/// 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>], DotDotPos),
/// A `box` pattern.
Box(&'hir Pat<'hir>),
/// A `deref` pattern (currently `deref!()` macro-based syntax).
Deref(&'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>]),
/// A placeholder for a pattern that wasn't well formed in some way.
Err(ErrorGuaranteed),
}
/// A statement.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct Stmt<'hir> {
pub hir_id: HirId,
pub kind: StmtKind<'hir>,
pub span: Span,
}
/// The contents of a statement.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum StmtKind<'hir> {
/// A local (`let`) binding.
Let(&'hir LetStmt<'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> = <init>;`).
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct LetStmt<'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, or `AssignDesugar` if it is the result of a complex
/// assignment desugaring. Otherwise will be `Normal`.
pub source: LocalSource,
}
/// Represents a single arm of a `match` expression, e.g.
/// `<pat> (if <guard>) => <body>`.
#[derive(Debug, Clone, Copy, 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<&'hir Expr<'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 [`LetStmt`]), 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, Clone, Copy, HashStable_Generic)]
pub struct LetExpr<'hir> {
pub span: Span,
pub pat: &'hir Pat<'hir>,
pub ty: Option<&'hir Ty<'hir>>,
pub init: &'hir Expr<'hir>,
/// `Recovered::Yes` when this let expressions is not in a syntactically valid location.
/// Used to prevent building MIR in such situations.
pub recovered: ast::Recovered,
}
#[derive(Debug, Clone, Copy, 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, Debug, HashStable_Generic)]
pub enum BlockCheckMode {
DefaultBlock,
UnsafeBlock(UnsafeSource),
}
#[derive(Copy, Clone, PartialEq, Debug, HashStable_Generic)]
pub enum UnsafeSource {
CompilerGenerated,
UserProvided,
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable_Generic)]
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)
/// - `coroutine_kind` would be `None`
///
/// All bodies have an **owner**, which can be accessed via the HIR
/// map using `body_owner_def_id()`.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct Body<'hir> {
pub params: &'hir [Param<'hir>],
pub value: &'hir Expr<'hir>,
}
impl<'hir> Body<'hir> {
pub fn id(&self) -> BodyId {
BodyId { hir_id: self.value.hir_id }
}
}
/// The type of source expression that caused this coroutine to be created.
#[derive(Clone, PartialEq, Eq, Debug, Copy, Hash, HashStable_Generic, Encodable, Decodable)]
pub enum CoroutineKind {
/// A coroutine that comes from a desugaring.
Desugared(CoroutineDesugaring, CoroutineSource),
/// A coroutine literal created via a `yield` inside a closure.
Coroutine(Movability),
}
impl CoroutineKind {
pub fn movability(self) -> Movability {
match self {
CoroutineKind::Desugared(CoroutineDesugaring::Async, _)
| CoroutineKind::Desugared(CoroutineDesugaring::AsyncGen, _) => Movability::Static,
CoroutineKind::Desugared(CoroutineDesugaring::Gen, _) => Movability::Movable,
CoroutineKind::Coroutine(mov) => mov,
}
}
}
impl CoroutineKind {
pub fn is_fn_like(self) -> bool {
matches!(self, CoroutineKind::Desugared(_, CoroutineSource::Fn))
}
}
impl fmt::Display for CoroutineKind {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
CoroutineKind::Desugared(d, k) => {
d.fmt(f)?;
k.fmt(f)
}
CoroutineKind::Coroutine(_) => f.write_str("coroutine"),
}
}
}
/// In the case of a coroutine created as part of an async/gen construct,
/// which kind of async/gen 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, Eq, Hash, Debug, Copy, HashStable_Generic, Encodable, Decodable)]
pub enum CoroutineSource {
/// An explicit `async`/`gen` block written by the user.
Block,
/// An explicit `async`/`gen` closure written by the user.
Closure,
/// The `async`/`gen` block generated as the body of an async/gen function.
Fn,
}
impl fmt::Display for CoroutineSource {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
CoroutineSource::Block => "block",
CoroutineSource::Closure => "closure body",
CoroutineSource::Fn => "fn body",
}
.fmt(f)
}
}
#[derive(Clone, PartialEq, Eq, Debug, Copy, Hash, HashStable_Generic, Encodable, Decodable)]
pub enum CoroutineDesugaring {
/// An explicit `async` block or the body of an `async` function.
Async,
/// An explicit `gen` block or the body of a `gen` function.
Gen,
/// An explicit `async gen` block or the body of an `async gen` function,
/// which is able to both `yield` and `.await`.
AsyncGen,
}
impl fmt::Display for CoroutineDesugaring {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
CoroutineDesugaring::Async => {
if f.alternate() {
f.write_str("`async` ")?;
} else {
f.write_str("async ")?
}
}
CoroutineDesugaring::Gen => {
if f.alternate() {
f.write_str("`gen` ")?;
} else {
f.write_str("gen ")?
}
}
CoroutineDesugaring::AsyncGen => {
if f.alternate() {
f.write_str("`async gen` ")?;
} else {
f.write_str("async gen ")?
}
}
}
Ok(())
}
}
#[derive(Copy, Clone, Debug)]
pub enum BodyOwnerKind {
/// Functions and methods.
Fn,
/// Closures
Closure,
/// Constants and associated constants, also including inline constants.
Const { inline: bool },
/// 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 { inline: bool },
}
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: `IntoDiagArg` impl for `ConstContext` lives in `rustc_errors`
// due to a cyclical dependency between hir that crate.
/// A literal.
pub type Lit = Spanned<LitKind>;
/// 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_def_id(..)`
#[derive(Copy, Clone, Debug, HashStable_Generic)]
pub struct AnonConst {
pub hir_id: HirId,
pub def_id: LocalDefId,
pub body: BodyId,
pub span: Span,
}
/// An inline constant expression `const { something }`.
#[derive(Copy, Clone, Debug, HashStable_Generic)]
pub struct ConstBlock {
pub hir_id: HirId,
pub def_id: LocalDefId,
pub body: BodyId,
}
/// An expression.
///
/// For more details, see the [rust lang reference].
/// Note that the reference does not document nightly-only features.
/// There may be also slight differences in the names and representation of AST nodes between
/// the compiler and the reference.
///
/// [rust lang reference]: https://doc.rust-lang.org/reference/expressions.html
#[derive(Debug, Clone, Copy, HashStable_Generic)]
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::Closure { .. } => ExprPrecedence::Closure,
ExprKind::Break(..)
| ExprKind::Continue(..)
| ExprKind::Ret(..)
| ExprKind::Yield(..)
| ExprKind::Become(..) => ExprPrecedence::Jump,
// Binop-like expr kinds, handled by `AssocOp`.
ExprKind::Binary(op, ..) => AssocOp::from_ast_binop(op.node).precedence(),
ExprKind::Cast(..) => ExprPrecedence::Cast,
ExprKind::Assign(..) |
ExprKind::AssignOp(..) => ExprPrecedence::Assign,
// Unary, prefix
ExprKind::AddrOf(..)
// Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
// However, this is not exactly right. When `let _ = a` is the LHS of a binop we
// need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
// but we need to print `(let _ = a) < b` as-is with parens.
| ExprKind::Let(..)
| ExprKind::Unary(..) => ExprPrecedence::Prefix,
// Never need parens
ExprKind::Array(_)
| ExprKind::Block(..)
| ExprKind::Call(..)
| ExprKind::ConstBlock(_)
| ExprKind::Field(..)
| ExprKind::If(..)
| ExprKind::Index(..)
| ExprKind::InlineAsm(..)
| ExprKind::Lit(_)
| ExprKind::Loop(..)
| ExprKind::Match(..)
| ExprKind::MethodCall(..)
| ExprKind::OffsetOf(..)
| ExprKind::Path(..)
| ExprKind::Repeat(..)
| ExprKind::Struct(..)
| ExprKind::Tup(_)
| ExprKind::Type(..)
| ExprKind::UnsafeBinderCast(..)
| ExprKind::Err(_) => ExprPrecedence::Unambiguous,
ExprKind::DropTemps(ref expr, ..) => expr.precedence(),
}
}
/// 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),
// Unsafe binder cast preserves place-ness of the sub-expression.
ExprKind::UnsafeBinderCast(_, 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::Become(..)
| ExprKind::Let(..)
| ExprKind::Loop(..)
| ExprKind::Assign(..)
| ExprKind::InlineAsm(..)
| ExprKind::OffsetOf(..)
| ExprKind::AssignOp(..)
| ExprKind::Lit(_)
| ExprKind::ConstBlock(..)
| ExprKind::Unary(..)
| 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 peel_borrows(&self) -> &Self {
let mut expr = self;
while let ExprKind::AddrOf(.., inner) = &expr.kind {
expr = inner;
}
expr
}
pub fn can_have_side_effects(&self) -> bool {
match self.peel_drop_temps().kind {
ExprKind::Path(_) | ExprKind::Lit(_) | ExprKind::OffsetOf(..) => false,
ExprKind::Type(base, _)
| ExprKind::Unary(_, base)
| ExprKind::Field(base, _)
| ExprKind::Index(base, _, _)
| ExprKind::AddrOf(.., base)
| ExprKind::Cast(base, _)
| ExprKind::UnsafeBinderCast(_, 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) => {
let init_side_effects = match init {
StructTailExpr::Base(init) => init.can_have_side_effects(),
StructTailExpr::DefaultFields(_) | StructTailExpr::None => false,
};
fields.iter().map(|field| field.expr).any(|e| e.can_have_side_effects())
|| init_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().any(|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::Become(..)
| ExprKind::Let(..)
| ExprKind::Loop(..)
| ExprKind::Assign(..)
| ExprKind::InlineAsm(..)
| ExprKind::AssignOp(..)
| ExprKind::ConstBlock(..)
| 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::Array(_)
| ExprKind::Call(..)
| ExprKind::Tup(_)
| ExprKind::Lit(_)
| ExprKind::Path(_)
| ExprKind::Struct(..) => true,
_ => false,
}
}
/// Whether this and the `other` expression are the same for purposes of an indexing operation.
///
/// This is only used for diagnostics to see if we have things like `foo[i]` where `foo` is
/// borrowed multiple times with `i`.
pub fn equivalent_for_indexing(&self, other: &Expr<'_>) -> bool {
match (self.kind, other.kind) {
(ExprKind::Lit(lit1), ExprKind::Lit(lit2)) => lit1.node == lit2.node,
(
ExprKind::Path(QPath::LangItem(item1, _)),
ExprKind::Path(QPath::LangItem(item2, _)),
) => item1 == item2,
(
ExprKind::Path(QPath::Resolved(None, path1)),
ExprKind::Path(QPath::Resolved(None, path2)),
) => path1.res == path2.res,
(
ExprKind::Struct(
QPath::LangItem(LangItem::RangeTo, _),
[val1],
StructTailExpr::None,
),
ExprKind::Struct(
QPath::LangItem(LangItem::RangeTo, _),
[val2],
StructTailExpr::None,
),
)
| (
ExprKind::Struct(
QPath::LangItem(LangItem::RangeToInclusive, _),
[val1],
StructTailExpr::None,
),
ExprKind::Struct(
QPath::LangItem(LangItem::RangeToInclusive, _),
[val2],
StructTailExpr::None,
),
)
| (
ExprKind::Struct(
QPath::LangItem(LangItem::RangeFrom, _),
[val1],
StructTailExpr::None,
),
ExprKind::Struct(
QPath::LangItem(LangItem::RangeFrom, _),
[val2],
StructTailExpr::None,
),
) => val1.expr.equivalent_for_indexing(val2.expr),
(
ExprKind::Struct(
QPath::LangItem(LangItem::Range, _),
[val1, val3],
StructTailExpr::None,
),
ExprKind::Struct(
QPath::LangItem(LangItem::Range, _),
[val2, val4],
StructTailExpr::None,
),
) => {
val1.expr.equivalent_for_indexing(val2.expr)
&& val3.expr.equivalent_for_indexing(val4.expr)
}
_ => 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, Clone, Copy, HashStable_Generic)]
pub enum ExprKind<'hir> {
/// Allow anonymous constants from an inline `const` block
ConstBlock(ConstBlock),
/// 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 `&Expr` is the expression that evaluates
/// to the object on which the method is being called on (the receiver),
/// and the `&[Expr]` is 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>, &'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(&'hir Lit),
/// A cast (e.g., `foo as f64`).
Cast(&'hir Expr<'hir>, &'hir Ty<'hir>),
/// A type ascription (e.g., `x: Foo`). See RFC 3307.
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 AST lowering.
/// An example of that is the desugaring of `for` loops.
DropTemps(&'hir Expr<'hir>),
/// A `let $pat = $expr` expression.
///
/// These are not [`LetStmt`] and only occur as expressions.
/// The `let Some(x) = foo()` in `if let Some(x) = foo()` is an example of `Let(..)`.
Let(&'hir LetExpr<'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 coroutine 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]`).
/// Similar to [`ExprKind::MethodCall`], the final `Span` represents the span of the brackets
/// and index.
Index(&'hir Expr<'hir>, &'hir Expr<'hir>, Span),
/// 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>>),
/// A `become`, with the value to be returned.
Become(&'hir Expr<'hir>),
/// Inline assembly (from `asm!`), with its outputs and inputs.
InlineAsm(&'hir InlineAsm<'hir>),
/// Field offset (`offset_of!`)
OffsetOf(&'hir Ty<'hir>, &'hir [Ident]),
/// 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>], StructTailExpr<'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>, &'hir ConstArg<'hir>),
/// A suspension point for coroutines (i.e., `yield <expr>`).
Yield(&'hir Expr<'hir>, YieldSource),
/// Operators which can be used to interconvert `unsafe` binder types.
/// e.g. `unsafe<'a> &'a i32` <=> `&i32`.
UnsafeBinderCast(UnsafeBinderCastKind, &'hir Expr<'hir>, Option<&'hir Ty<'hir>>),
/// A placeholder for an expression that wasn't syntactically well formed in some way.
Err(rustc_span::ErrorGuaranteed),
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum StructTailExpr<'hir> {
/// A struct expression where all the fields are explicitly enumerated: `Foo { a, b }`.
None,
/// A struct expression with a "base", an expression of the same type as the outer struct that
/// will be used to populate any fields not explicitly mentioned: `Foo { ..base }`
Base(&'hir Expr<'hir>),
/// A struct expression with a `..` tail but no "base" expression. The values from the struct
/// fields' default values will be used to populate any fields not explicitly mentioned:
/// `Foo { .. }`.
DefaultFields(Span),
}
/// 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, Clone, Copy, 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.
LangItem(LangItem, Span),
}
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,
}
}
}
/// Hints at the original code for a let statement.
#[derive(Copy, Clone, 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, array or underscore expression.
/// The span is that of the `=` sign.
AssignDesugar(Span),
}
/// Hints at the original code for a `match _ { .. }`.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable_Generic, Encodable, Decodable)]
pub enum MatchSource {
/// A `match _ { .. }`.
Normal,
/// A `expr.match { .. }`.
Postfix,
/// A desugared `for _ in _ { .. }` loop.
ForLoopDesugar,
/// A desugared `?` operator.
TryDesugar(HirId),
/// A desugared `<expr>.await`.
AwaitDesugar,
/// A desugared `format_args!()`.
FormatArgs,
}
impl MatchSource {
#[inline]
pub const fn name(self) -> &'static str {
use MatchSource::*;
match self {
Normal => "match",
Postfix => ".match",
ForLoopDesugar => "for",
TryDesugar(_) => "?",
AwaitDesugar => ".await",
FormatArgs => "format_args!()",
}
}
}
/// The loop type that yielded an `ExprKind::Loop`.
#[derive(Copy, Clone, PartialEq, 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, Debug, PartialEq, 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, 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, Debug, HashStable_Generic)]
pub enum YieldSource {
/// An `<expr>.await`.
Await { expr: Option<HirId> },
/// A plain `yield`.
Yield,
}
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`",
})
}
}
// N.B., if you change this, you'll probably want to change the corresponding
// type structure in middle/ty.rs as well.
#[derive(Debug, Clone, Copy, 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, Clone, Copy, 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 owner_id: OwnerId,
}
impl TraitItemId {
#[inline]
pub fn hir_id(&self) -> HirId {
// Items are always HIR owners.
HirId::make_owner(self.owner_id.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, Clone, Copy, HashStable_Generic)]
pub struct TraitItem<'hir> {
pub ident: Ident,
pub owner_id: OwnerId,
pub generics: &'hir Generics<'hir>,
pub kind: TraitItemKind<'hir>,
pub span: Span,
pub defaultness: Defaultness,
}
macro_rules! expect_methods_self_kind {
( $( $name:ident, $ret_ty:ty, $pat:pat, $ret_val:expr; )* ) => {
$(
#[track_caller]
pub fn $name(&self) -> $ret_ty {
let $pat = &self.kind else { expect_failed(stringify!($ident), self) };
$ret_val
}
)*
}
}
macro_rules! expect_methods_self {
( $( $name:ident, $ret_ty:ty, $pat:pat, $ret_val:expr; )* ) => {
$(
#[track_caller]
pub fn $name(&self) -> $ret_ty {
let $pat = self else { expect_failed(stringify!($ident), self) };
$ret_val
}
)*
}
}
#[track_caller]
fn expect_failed<T: fmt::Debug>(ident: &'static str, found: T) -> ! {
panic!("{ident}: found {found:?}")
}
impl<'hir> TraitItem<'hir> {
#[inline]
pub fn hir_id(&self) -> HirId {
// Items are always HIR owners.
HirId::make_owner(self.owner_id.def_id)
}
pub fn trait_item_id(&self) -> TraitItemId {
TraitItemId { owner_id: self.owner_id }
}
expect_methods_self_kind! {
expect_const, (&'hir Ty<'hir>, Option<BodyId>),
TraitItemKind::Const(ty, body), (ty, *body);
expect_fn, (&FnSig<'hir>, &TraitFn<'hir>),
TraitItemKind::Fn(ty, trfn), (ty, trfn);
expect_type, (GenericBounds<'hir>, Option<&'hir Ty<'hir>>),
TraitItemKind::Type(bounds, ty), (bounds, *ty);
}
}
/// Represents a trait method's body (or just argument names).
#[derive(Debug, Clone, Copy, 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, Clone, Copy, 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 owner_id: OwnerId,
}
impl ImplItemId {
#[inline]
pub fn hir_id(&self) -> HirId {
// Items are always HIR owners.
HirId::make_owner(self.owner_id.def_id)
}
}
/// Represents an associated item within an impl block.
///
/// Refer to [`Impl`] for an impl block declaration.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct ImplItem<'hir> {
pub ident: Ident,
pub owner_id: OwnerId,
pub generics: &'hir Generics<'hir>,
pub kind: ImplItemKind<'hir>,
pub defaultness: Defaultness,
pub span: Span,
pub vis_span: Span,
}
impl<'hir> ImplItem<'hir> {
#[inline]
pub fn hir_id(&self) -> HirId {
// Items are always HIR owners.
HirId::make_owner(self.owner_id.def_id)
}
pub fn impl_item_id(&self) -> ImplItemId {
ImplItemId { owner_id: self.owner_id }
}
expect_methods_self_kind! {
expect_const, (&'hir Ty<'hir>, BodyId), ImplItemKind::Const(ty, body), (ty, *body);
expect_fn, (&FnSig<'hir>, BodyId), ImplItemKind::Fn(ty, body), (ty, *body);
expect_type, &'hir Ty<'hir>, ImplItemKind::Type(ty), ty;
}
}
/// Represents various kinds of content within an `impl`.
#[derive(Debug, Clone, Copy, 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.
Type(&'hir Ty<'hir>),
}
/// A constraint on an associated item.
///
/// ### Examples
///
/// * the `A = Ty` and `B = Ty` in `Trait<A = Ty, B = Ty>`
/// * the `G<Ty> = Ty` in `Trait<G<Ty> = Ty>`
/// * the `A: Bound` in `Trait<A: Bound>`
/// * the `RetTy` in `Trait(ArgTy, ArgTy) -> RetTy`
/// * the `C = { Ct }` in `Trait<C = { Ct }>` (feature `associated_const_equality`)
/// * the `f(..): Bound` in `Trait<f(..): Bound>` (feature `return_type_notation`)
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct AssocItemConstraint<'hir> {
pub hir_id: HirId,
pub ident: Ident,
pub gen_args: &'hir GenericArgs<'hir>,
pub kind: AssocItemConstraintKind<'hir>,
pub span: Span,
}
impl<'hir> AssocItemConstraint<'hir> {
/// Obtain the type on the RHS of an assoc ty equality constraint if applicable.
pub fn ty(self) -> Option<&'hir Ty<'hir>> {
match self.kind {
AssocItemConstraintKind::Equality { term: Term::Ty(ty) } => Some(ty),
_ => None,
}
}
/// Obtain the const on the RHS of an assoc const equality constraint if applicable.
pub fn ct(self) -> Option<&'hir ConstArg<'hir>> {
match self.kind {
AssocItemConstraintKind::Equality { term: Term::Const(ct) } => Some(ct),
_ => None,
}
}
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum Term<'hir> {
Ty(&'hir Ty<'hir>),
Const(&'hir ConstArg<'hir>),
}
impl<'hir> From<&'hir Ty<'hir>> for Term<'hir> {
fn from(ty: &'hir Ty<'hir>) -> Self {
Term::Ty(ty)
}
}
impl<'hir> From<&'hir ConstArg<'hir>> for Term<'hir> {
fn from(c: &'hir ConstArg<'hir>) -> Self {
Term::Const(c)
}
}
/// The kind of [associated item constraint][AssocItemConstraint].
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum AssocItemConstraintKind<'hir> {
/// An equality constraint for an associated item (e.g., `AssocTy = Ty` in `Trait<AssocTy = Ty>`).
///
/// Also known as an *associated item binding* (we *bind* an associated item to a term).
///
/// Furthermore, associated type equality constraints can also be referred to as *associated type
/// bindings*. Similarly with associated const equality constraints and *associated const bindings*.
Equality { term: Term<'hir> },
/// A bound on an associated type (e.g., `AssocTy: Bound` in `Trait<AssocTy: Bound>`).
Bound { bounds: &'hir [GenericBound<'hir>] },
}
impl<'hir> AssocItemConstraintKind<'hir> {
pub fn descr(&self) -> &'static str {
match self {
AssocItemConstraintKind::Equality { .. } => "binding",
AssocItemConstraintKind::Bound { .. } => "constraint",
}
}
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
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::SelfTyParam { trait_: def_id } => {
Some((def_id, segment.ident))
}
_ => None,
}
}
pub fn peel_refs(&self) -> &Self {
let mut final_ty = self;
while let TyKind::Ref(_, MutTy { ty, .. }) = &final_ty.kind {
final_ty = ty;
}
final_ty
}
pub fn find_self_aliases(&self) -> Vec<Span> {
use crate::intravisit::Visitor;
struct MyVisitor(Vec<Span>);
impl<'v> Visitor<'v> for MyVisitor {
fn visit_ty(&mut self, t: &'v Ty<'v>) {
if matches!(
&t.kind,
TyKind::Path(QPath::Resolved(_, Path {
res: crate::def::Res::SelfTyAlias { .. },
..
},))
) {
self.0.push(t.span);
return;
}
crate::intravisit::walk_ty(self, t);
}
}
let mut my_visitor = MyVisitor(vec![]);
my_visitor.visit_ty(self);
my_visitor.0
}
/// Whether `ty` is a type with `_` placeholders that can be inferred. Used in diagnostics only to
/// use inference to provide suggestions for the appropriate type if possible.
pub fn is_suggestable_infer_ty(&self) -> bool {
fn are_suggestable_generic_args(generic_args: &[GenericArg<'_>]) -> bool {
generic_args.iter().any(|arg| match arg {
GenericArg::Type(ty) => ty.is_suggestable_infer_ty(),
GenericArg::Infer(_) => true,
_ => false,
})
}
debug!(?self);
match &self.kind {
TyKind::Infer => true,
TyKind::Slice(ty) => ty.is_suggestable_infer_ty(),
TyKind::Array(ty, length) => {
ty.is_suggestable_infer_ty() || matches!(length.kind, ConstArgKind::Infer(..))
}
TyKind::Tup(tys) => tys.iter().any(Self::is_suggestable_infer_ty),
TyKind::Ptr(mut_ty) | TyKind::Ref(_, mut_ty) => mut_ty.ty.is_suggestable_infer_ty(),
TyKind::Path(QPath::TypeRelative(ty, segment)) => {
ty.is_suggestable_infer_ty() || are_suggestable_generic_args(segment.args().args)
}
TyKind::Path(QPath::Resolved(ty_opt, Path { segments, .. })) => {
ty_opt.is_some_and(Self::is_suggestable_infer_ty)
|| segments
.iter()
.any(|segment| are_suggestable_generic_args(segment.args().args))
}
_ => false,
}
}
}
/// Not represented directly in the AST; referred to by name through a `ty_path`.
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Hash, Debug, 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; 19] = [
// 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::F16),
Self::Float(FloatTy::F32),
Self::Float(FloatTy::F64),
Self::Float(FloatTy::F128),
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::f16 => Self::Float(FloatTy::F16),
sym::f32 => Self::Float(FloatTy::F32),
sym::f64 => Self::Float(FloatTy::F64),
sym::f128 => Self::Float(FloatTy::F128),
sym::bool => Self::Bool,
sym::char => Self::Char,
sym::str => Self::Str,
_ => return None,
};
Some(ty)
}
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct BareFnTy<'hir> {
pub safety: Safety,
pub abi: ExternAbi,
pub generic_params: &'hir [GenericParam<'hir>],
pub decl: &'hir FnDecl<'hir>,
pub param_names: &'hir [Ident],
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct UnsafeBinderTy<'hir> {
pub generic_params: &'hir [GenericParam<'hir>],
pub inner_ty: &'hir Ty<'hir>,
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct OpaqueTy<'hir> {
pub hir_id: HirId,
pub def_id: LocalDefId,
pub bounds: GenericBounds<'hir>,
pub origin: OpaqueTyOrigin<LocalDefId>,
pub span: Span,
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum PreciseCapturingArg<'hir> {
Lifetime(&'hir Lifetime),
/// Non-lifetime argument (type or const)
Param(PreciseCapturingNonLifetimeArg),
}
impl PreciseCapturingArg<'_> {
pub fn hir_id(self) -> HirId {
match self {
PreciseCapturingArg::Lifetime(lt) => lt.hir_id,
PreciseCapturingArg::Param(param) => param.hir_id,
}
}
pub fn name(self) -> Symbol {
match self {
PreciseCapturingArg::Lifetime(lt) => lt.ident.name,
PreciseCapturingArg::Param(param) => param.ident.name,
}
}
}
/// We need to have a [`Node`] for the [`HirId`] that we attach the type/const param
/// resolution to. Lifetimes don't have this problem, and for them, it's actually
/// kind of detrimental to use a custom node type versus just using [`Lifetime`],
/// since resolve_bound_vars operates on `Lifetime`s.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct PreciseCapturingNonLifetimeArg {
pub hir_id: HirId,
pub ident: Ident,
pub res: Res,
}
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[derive(HashStable_Generic, Encodable, Decodable)]
pub enum RpitContext {
Trait,
TraitImpl,
}
/// From whence the opaque type came.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[derive(HashStable_Generic, Encodable, Decodable)]
pub enum OpaqueTyOrigin<D> {
/// `-> impl Trait`
FnReturn {
/// The defining function.
parent: D,
// Whether this is an RPITIT (return position impl trait in trait)
in_trait_or_impl: Option<RpitContext>,
},
/// `async fn`
AsyncFn {
/// The defining function.
parent: D,
// Whether this is an AFIT (async fn in trait)
in_trait_or_impl: Option<RpitContext>,
},
/// type aliases: `type Foo = impl Trait;`
TyAlias {
/// The type alias or associated type parent of the TAIT/ATPIT
parent: D,
/// associated types in impl blocks for traits.
in_assoc_ty: bool,
},
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, HashStable_Generic)]
pub enum InferDelegationKind {
Input(usize),
Output,
}
/// The various kinds of types recognized by the compiler.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum TyKind<'hir> {
/// Actual type should be inherited from `DefId` signature
InferDelegation(DefId, InferDelegationKind),
/// A variable length slice (i.e., `[T]`).
Slice(&'hir Ty<'hir>),
/// A fixed length array (i.e., `[T; n]`).
Array(&'hir Ty<'hir>, &'hir ConstArg<'hir>),
/// A raw pointer (i.e., `*const T` or `*mut T`).
Ptr(MutTy<'hir>),
/// A reference (i.e., `&'a T` or `&'a mut T`).
Ref(&'hir Lifetime, MutTy<'hir>),
/// A bare function (e.g., `fn(usize) -> bool`).
BareFn(&'hir BareFnTy<'hir>),
/// Uwu
UnsafeBinder(&'hir UnsafeBinderTy<'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`.
OpaqueDef(&'hir OpaqueTy<'hir>),
/// A trait object type `Bound1 + Bound2 + Bound3`
/// where `Bound` is a trait or a lifetime.
TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax),
/// Unused for now.
Typeof(&'hir AnonConst),
/// `TyKind::Infer` means the type should be inferred instead of it having been
/// specified. This can appear anywhere in a type.
///
/// **Note:** Not all inferred types are represented as
/// `TyKind::Infer`. In cases where it is ambiguous whether
/// a generic arg is a type or a const, inference variables are
/// represented as `GenericArg::Infer` instead.
Infer,
/// Placeholder for a type that has failed to be defined.
Err(rustc_span::ErrorGuaranteed),
/// Pattern types (`pattern_type!(u32 is 1..)`)
Pat(&'hir Ty<'hir>, &'hir Pat<'hir>),
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum InlineAsmOperand<'hir> {
In {
reg: InlineAsmRegOrRegClass,
expr: &'hir Expr<'hir>,
},
Out {
reg: InlineAsmRegOrRegClass,
late: bool,
expr: Option<&'hir Expr<'hir>>,
},
InOut {
reg: InlineAsmRegOrRegClass,
late: bool,
expr: &'hir Expr<'hir>,
},
SplitInOut {
reg: InlineAsmRegOrRegClass,
late: bool,
in_expr: &'hir Expr<'hir>,
out_expr: Option<&'hir Expr<'hir>>,
},
Const {
anon_const: &'hir AnonConst,
},
SymFn {
anon_const: &'hir AnonConst,
},
SymStatic {
path: QPath<'hir>,
def_id: DefId,
},
Label {
block: &'hir Block<'hir>,
},
}
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 { .. }
| Self::Label { .. } => None,
}
}
pub fn is_clobber(&self) -> bool {
matches!(self, InlineAsmOperand::Out {
reg: InlineAsmRegOrRegClass::Reg(_),
late: _,
expr: None
})
}
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct InlineAsm<'hir> {
pub asm_macro: ast::AsmMacro,
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],
}
impl InlineAsm<'_> {
pub fn contains_label(&self) -> bool {
self.operands.iter().any(|x| matches!(x.0, InlineAsmOperand::Label { .. }))
}
}
/// Represents a parameter in a function header.
#[derive(Debug, Clone, Copy, 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, Clone, Copy, 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,
/// Is lifetime elision allowed.
pub lifetime_elision_allowed: bool,
}
impl<'hir> FnDecl<'hir> {
pub fn opt_delegation_sig_id(&self) -> Option<DefId> {
if let FnRetTy::Return(ty) = self.output
&& let TyKind::InferDelegation(sig_id, _) = ty.kind
{
return Some(sig_id);
}
None
}
}
/// Represents what type of implicit self a function has, if any.
#[derive(Copy, Clone, PartialEq, Eq, 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);`.
RefImm,
/// Represents a `fn x(&mut self);`.
RefMut,
/// 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, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum IsAsync {
Async(Span),
NotAsync,
}
impl IsAsync {
pub fn is_async(self) -> bool {
matches!(self, IsAsync::Async(_))
}
}
#[derive(Copy, Clone, PartialEq, Eq, 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, Clone, Copy, 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<'hir> FnRetTy<'hir> {
#[inline]
pub fn span(&self) -> Span {
match *self {
Self::DefaultReturn(span) => span,
Self::Return(ref ty) => ty.span,
}
}
pub fn get_infer_ret_ty(&self) -> Option<&'hir Ty<'hir>> {
if let Self::Return(ty) = self {
if ty.is_suggestable_infer_ty() {
return Some(*ty);
}
}
None
}
}
/// 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(Debug, Clone, Copy, HashStable_Generic)]
pub struct Mod<'hir> {
pub spans: ModSpans,
pub item_ids: &'hir [ItemId],
}
#[derive(Copy, Clone, Debug, HashStable_Generic)]
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, Clone, Copy, HashStable_Generic)]
pub struct EnumDef<'hir> {
pub variants: &'hir [Variant<'hir>],
}
#[derive(Debug, Clone, Copy, 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 hir_id: HirId,
pub def_id: LocalDefId,
/// Fields and constructor id of the variant.
pub data: VariantData<'hir>,
/// Explicit discriminant (e.g., `Foo = 1`).
pub disr_expr: Option<&'hir AnonConst>,
/// Span
pub span: Span,
}
#[derive(Copy, Clone, PartialEq, 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, Copy, 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,
res => panic!("{res:?} did not resolve to a trait or trait alias"),
}
}
}
#[derive(Clone, Debug, Copy, HashStable_Generic)]
pub struct PolyTraitRef<'hir> {
/// The `'a` in `for<'a> Foo<&'a T>`.
pub bound_generic_params: &'hir [GenericParam<'hir>],
/// The constness and polarity of the trait ref.
///
/// The `async` modifier is lowered directly into a different trait for now.
pub modifiers: TraitBoundModifiers,
/// The `Foo<&'a T>` in `for<'a> Foo<&'a T>`.
pub trait_ref: TraitRef<'hir>,
pub span: Span,
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct FieldDef<'hir> {
pub span: Span,
pub vis_span: Span,
pub ident: Ident,
pub hir_id: HirId,
pub def_id: LocalDefId,
pub ty: &'hir Ty<'hir>,
pub safety: Safety,
pub default: Option<&'hir AnonConst>,
}
impl FieldDef<'_> {
// Still necessary in couple of places
pub fn is_positional(&self) -> bool {
self.ident.as_str().as_bytes()[0].is_ascii_digit()
}
}
/// Fields and constructor IDs of enum variants and structs.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum VariantData<'hir> {
/// A struct variant.
///
/// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
Struct { fields: &'hir [FieldDef<'hir>], recovered: ast::Recovered },
/// A tuple variant.
///
/// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
Tuple(&'hir [FieldDef<'hir>], HirId, LocalDefId),
/// A unit variant.
///
/// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
Unit(HirId, LocalDefId),
}
impl<'hir> VariantData<'hir> {
/// Return the fields of this variant.
pub fn fields(&self) -> &'hir [FieldDef<'hir>] {
match *self {
VariantData::Struct { fields, .. } | VariantData::Tuple(fields, ..) => fields,
_ => &[],
}
}
pub fn ctor(&self) -> Option<(CtorKind, HirId, LocalDefId)> {
match *self {
VariantData::Tuple(_, hir_id, def_id) => Some((CtorKind::Fn, hir_id, def_id)),
VariantData::Unit(hir_id, def_id) => Some((CtorKind::Const, hir_id, def_id)),
VariantData::Struct { .. } => None,
}
}
#[inline]
pub fn ctor_kind(&self) -> Option<CtorKind> {
self.ctor().map(|(kind, ..)| kind)
}
/// Return the `HirId` of this variant's constructor, if it has one.
#[inline]
pub fn ctor_hir_id(&self) -> Option<HirId> {
self.ctor().map(|(_, hir_id, _)| hir_id)
}
/// Return the `LocalDefId` of this variant's constructor, if it has one.
#[inline]
pub fn ctor_def_id(&self) -> Option<LocalDefId> {
self.ctor().map(|(.., def_id)| def_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 owner_id: OwnerId,
}
impl ItemId {
#[inline]
pub fn hir_id(&self) -> HirId {
// Items are always HIR owners.
HirId::make_owner(self.owner_id.def_id)
}
}
/// An item
///
/// The name might be a dummy name in case of anonymous items
///
/// For more details, see the [rust lang reference].
/// Note that the reference does not document nightly-only features.
/// There may be also slight differences in the names and representation of AST nodes between
/// the compiler and the reference.
///
/// [rust lang reference]: https://doc.rust-lang.org/reference/items.html
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct Item<'hir> {
pub ident: Ident,
pub owner_id: OwnerId,
pub kind: ItemKind<'hir>,
pub span: Span,
pub vis_span: Span,
}
impl<'hir> Item<'hir> {
#[inline]
pub fn hir_id(&self) -> HirId {
// Items are always HIR owners.
HirId::make_owner(self.owner_id.def_id)
}
pub fn item_id(&self) -> ItemId {
ItemId { owner_id: self.owner_id }
}
/// Check if this is an [`ItemKind::Enum`], [`ItemKind::Struct`] or
/// [`ItemKind::Union`].
pub fn is_adt(&self) -> bool {
matches!(self.kind, ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..))
}
/// Check if this is an [`ItemKind::Struct`] or [`ItemKind::Union`].
pub fn is_struct_or_union(&self) -> bool {
matches!(self.kind, ItemKind::Struct(..) | ItemKind::Union(..))
}
expect_methods_self_kind! {
expect_extern_crate, Option<Symbol>, ItemKind::ExternCrate(s), *s;
expect_use, (&'hir UsePath<'hir>, UseKind), ItemKind::Use(p, uk), (p, *uk);
expect_static, (&'hir Ty<'hir>, Mutability, BodyId),
ItemKind::Static(ty, mutbl, body), (ty, *mutbl, *body);
expect_const, (&'hir Ty<'hir>, &'hir Generics<'hir>, BodyId),
ItemKind::Const(ty, generics, body), (ty, generics, *body);
expect_fn, (&FnSig<'hir>, &'hir Generics<'hir>, BodyId),
ItemKind::Fn(sig, generics, body), (sig, generics, *body);
expect_macro, (&ast::MacroDef, MacroKind), ItemKind::Macro(def, mk), (def, *mk);
expect_mod, &'hir Mod<'hir>, ItemKind::Mod(m), m;
expect_foreign_mod, (ExternAbi, &'hir [ForeignItemRef]),
ItemKind::ForeignMod { abi, items }, (*abi, items);
expect_global_asm, &'hir InlineAsm<'hir>, ItemKind::GlobalAsm(asm), asm;
expect_ty_alias, (&'hir Ty<'hir>, &'hir Generics<'hir>),
ItemKind::TyAlias(ty, generics), (ty, generics);
expect_enum, (&EnumDef<'hir>, &'hir Generics<'hir>), ItemKind::Enum(def, generics), (def, generics);
expect_struct, (&VariantData<'hir>, &'hir Generics<'hir>),
ItemKind::Struct(data, generics), (data, generics);
expect_union, (&VariantData<'hir>, &'hir Generics<'hir>),
ItemKind::Union(data, generics), (data, generics);
expect_trait,
(IsAuto, Safety, &'hir Generics<'hir>, GenericBounds<'hir>, &'hir [TraitItemRef]),
ItemKind::Trait(is_auto, safety, generics, bounds, items),
(*is_auto, *safety, generics, bounds, items);
expect_trait_alias, (&'hir Generics<'hir>, GenericBounds<'hir>),
ItemKind::TraitAlias(generics, bounds), (generics, bounds);
expect_impl, &'hir Impl<'hir>, ItemKind::Impl(imp), imp;
}
}
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
#[derive(Encodable, Decodable, HashStable_Generic)]
pub enum Safety {
Unsafe,
Safe,
}
impl Safety {
pub fn prefix_str(self) -> &'static str {
match self {
Self::Unsafe => "unsafe ",
Self::Safe => "",
}
}
}
impl fmt::Display for Safety {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(match *self {
Self::Unsafe => "unsafe",
Self::Safe => "safe",
})
}
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, 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, Debug, HashStable_Generic)]
pub struct FnHeader {
pub safety: Safety,
pub constness: Constness,
pub asyncness: IsAsync,
pub abi: ExternAbi,
}
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.safety, Safety::Unsafe)
}
}
#[derive(Debug, Clone, Copy, 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 UsePath<'hir>, UseKind),
/// A `static` item.
Static(&'hir Ty<'hir>, Mutability, BodyId),
/// A `const` item.
Const(&'hir Ty<'hir>, &'hir Generics<'hir>, BodyId),
/// A function declaration.
Fn(FnSig<'hir>, &'hir Generics<'hir>, BodyId),
/// A MBE macro definition (`macro_rules!` or `macro`).
Macro(&'hir ast::MacroDef, MacroKind),
/// A module.
Mod(&'hir Mod<'hir>),
/// An external module, e.g. `extern { .. }`.
ForeignMod { abi: ExternAbi, 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 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, Safety, &'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>),
}
/// Represents an impl block declaration.
///
/// E.g., `impl $Type { .. }` or `impl $Trait for $Type { .. }`
/// Refer to [`ImplItem`] for an associated item within an impl block.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct Impl<'hir> {
pub constness: Constness,
pub safety: Safety,
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 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::Const(_, 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::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(Debug, Clone, Copy, 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, Clone, Copy, 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, 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 owner_id: OwnerId,
}
impl ForeignItemId {
#[inline]
pub fn hir_id(&self) -> HirId {
// Items are always HIR owners.
HirId::make_owner(self.owner_id.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, Clone, Copy, HashStable_Generic)]
pub struct ForeignItemRef {
pub id: ForeignItemId,
pub ident: Ident,
pub span: Span,
}
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub struct ForeignItem<'hir> {
pub ident: Ident,
pub kind: ForeignItemKind<'hir>,
pub owner_id: OwnerId,
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.owner_id.def_id)
}
pub fn foreign_item_id(&self) -> ForeignItemId {
ForeignItemId { owner_id: self.owner_id }
}
}
/// An item within an `extern` block.
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum ForeignItemKind<'hir> {
/// A foreign function.
Fn(FnSig<'hir>, &'hir [Ident], &'hir Generics<'hir>),
/// A foreign static item (`static ext: u8`).
Static(&'hir Ty<'hir>, Mutability, Safety),
/// A foreign type.
Type,
}
/// A variable captured by a closure.
#[derive(Debug, Copy, Clone, 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(Debug, Clone, 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>),
Synthetic,
}
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(..) | OwnerNode::Synthetic => 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,
OwnerNode::Synthetic => unreachable!(),
}
}
pub fn fn_sig(self) -> Option<&'hir FnSig<'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, _, _), .. })
| OwnerNode::ForeignItem(ForeignItem {
kind: ForeignItemKind::Fn(fn_sig, _, _), ..
}) => Some(fn_sig),
_ => None,
}
}
pub fn fn_decl(self) -> Option<&'hir 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, _, _), .. })
| OwnerNode::ForeignItem(ForeignItem {
kind: ForeignItemKind::Fn(fn_sig, _, _), ..
}) => Some(fn_sig.decl),
_ => None,
}
}
pub fn body_id(&self) -> Option<BodyId> {
match self {
OwnerNode::Item(Item {
kind:
ItemKind::Static(_, _, body)
| ItemKind::Const(_, _, body)
| ItemKind::Fn(_, _, body),
..
})
| OwnerNode::TraitItem(TraitItem {
kind:
TraitItemKind::Fn(_, TraitFn::Provided(body)) | TraitItemKind::Const(_, Some(body)),
..
})
| OwnerNode::ImplItem(ImplItem {
kind: ImplItemKind::Fn(_, body) | ImplItemKind::Const(_, body),
..
}) => Some(*body),
_ => None,
}
}
pub fn generics(self) -> Option<&'hir Generics<'hir>> {
Node::generics(self.into())
}
pub fn def_id(self) -> OwnerId {
match self {
OwnerNode::Item(Item { owner_id, .. })
| OwnerNode::TraitItem(TraitItem { owner_id, .. })
| OwnerNode::ImplItem(ImplItem { owner_id, .. })
| OwnerNode::ForeignItem(ForeignItem { owner_id, .. }) => *owner_id,
OwnerNode::Crate(..) => crate::CRATE_HIR_ID.owner,
OwnerNode::Synthetic => unreachable!(),
}
}
/// Check if node is an impl block.
pub fn is_impl_block(&self) -> bool {
matches!(self, OwnerNode::Item(Item { kind: ItemKind::Impl(_), .. }))
}
expect_methods_self! {
expect_item, &'hir Item<'hir>, OwnerNode::Item(n), n;
expect_foreign_item, &'hir ForeignItem<'hir>, OwnerNode::ForeignItem(n), n;
expect_impl_item, &'hir ImplItem<'hir>, OwnerNode::ImplItem(n), n;
expect_trait_item, &'hir TraitItem<'hir>, OwnerNode::TraitItem(n), n;
}
}
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),
OwnerNode::Synthetic => Node::Synthetic,
}
}
}
#[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),
ConstBlock(&'hir ConstBlock),
ConstArg(&'hir ConstArg<'hir>),
Expr(&'hir Expr<'hir>),
ExprField(&'hir ExprField<'hir>),
Stmt(&'hir Stmt<'hir>),
PathSegment(&'hir PathSegment<'hir>),
Ty(&'hir Ty<'hir>),
AssocItemConstraint(&'hir AssocItemConstraint<'hir>),
TraitRef(&'hir TraitRef<'hir>),
OpaqueTy(&'hir OpaqueTy<'hir>),
Pat(&'hir Pat<'hir>),
PatField(&'hir PatField<'hir>),
Arm(&'hir Arm<'hir>),
Block(&'hir Block<'hir>),
LetStmt(&'hir LetStmt<'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),
WherePredicate(&'hir WherePredicate<'hir>),
PreciseCapturingNonLifetimeArg(&'hir PreciseCapturingNonLifetimeArg),
// Created by query feeding
Synthetic,
Err(Span),
}
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()
/// .map(|ctor_id| tcx.parent_hir_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.ident),
Node::GenericParam(p) => Some(p.name.ident()),
Node::AssocItemConstraint(c) => Some(c.ident),
Node::PatField(f) => Some(f.ident),
Node::ExprField(f) => Some(f.ident),
Node::PreciseCapturingNonLifetimeArg(a) => Some(a.ident),
Node::Param(..)
| Node::AnonConst(..)
| Node::ConstBlock(..)
| Node::ConstArg(..)
| Node::Expr(..)
| Node::Stmt(..)
| Node::Block(..)
| Node::Ctor(..)
| Node::Pat(..)
| Node::Arm(..)
| Node::LetStmt(..)
| Node::Crate(..)
| Node::Ty(..)
| Node::TraitRef(..)
| Node::OpaqueTy(..)
| Node::Infer(..)
| Node::WherePredicate(..)
| Node::Synthetic
| Node::Err(..) => 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, _, _), .. })
| Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_sig, _, _), .. }) => {
Some(fn_sig.decl)
}
Node::Expr(Expr { kind: ExprKind::Closure(Closure { fn_decl, .. }), .. }) => {
Some(fn_decl)
}
_ => None,
}
}
/// Get a `hir::Impl` if the node is an impl block for the given `trait_def_id`.
pub fn impl_block_of_trait(self, trait_def_id: DefId) -> Option<&'hir Impl<'hir>> {
match self {
Node::Item(Item { kind: ItemKind::Impl(impl_block), .. })
if impl_block
.of_trait
.and_then(|trait_ref| trait_ref.trait_def_id())
.is_some_and(|trait_id| trait_id == trait_def_id) =>
{
Some(impl_block)
}
_ => 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, _, _), .. })
| Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_sig, _, _), .. }) => {
Some(fn_sig)
}
_ => None,
}
}
/// Get the type for constants, assoc types, type aliases and statics.
pub fn ty(self) -> Option<&'hir Ty<'hir>> {
match self {
Node::Item(it) => match it.kind {
ItemKind::TyAlias(ty, _)
| ItemKind::Static(ty, _, _)
| ItemKind::Const(ty, _, _) => Some(ty),
ItemKind::Impl(impl_item) => Some(&impl_item.self_ty),
_ => None,
},
Node::TraitItem(it) => match it.kind {
TraitItemKind::Const(ty, _) => Some(ty),
TraitItemKind::Type(_, ty) => ty,
_ => None,
},
Node::ImplItem(it) => match it.kind {
ImplItemKind::Const(ty, _) => Some(ty),
ImplItemKind::Type(ty) => Some(ty),
_ => None,
},
_ => None,
}
}
pub fn alias_ty(self) -> Option<&'hir Ty<'hir>> {
match self {
Node::Item(Item { kind: ItemKind::TyAlias(ty, ..), .. }) => Some(ty),
_ => None,
}
}
#[inline]
pub fn associated_body(&self) -> Option<(LocalDefId, BodyId)> {
match self {
Node::Item(Item {
owner_id,
kind:
ItemKind::Const(_, _, body) | ItemKind::Static(.., body) | ItemKind::Fn(.., body),
..
})
| Node::TraitItem(TraitItem {
owner_id,
kind:
TraitItemKind::Const(_, Some(body)) | TraitItemKind::Fn(_, TraitFn::Provided(body)),
..
})
| Node::ImplItem(ImplItem {
owner_id,
kind: ImplItemKind::Const(_, body) | ImplItemKind::Fn(_, body),
..
}) => Some((owner_id.def_id, *body)),
Node::Expr(Expr { kind: ExprKind::Closure(Closure { def_id, body, .. }), .. }) => {
Some((*def_id, *body))
}
Node::AnonConst(constant) => Some((constant.def_id, constant.body)),
Node::ConstBlock(constant) => Some((constant.def_id, constant.body)),
_ => None,
}
}
pub fn body_id(&self) -> Option<BodyId> {
Some(self.associated_body()?.1)
}
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)),
Node::Synthetic => Some(OwnerNode::Synthetic),
_ => 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,
}
}
expect_methods_self! {
expect_param, &'hir Param<'hir>, Node::Param(n), n;
expect_item, &'hir Item<'hir>, Node::Item(n), n;
expect_foreign_item, &'hir ForeignItem<'hir>, Node::ForeignItem(n), n;
expect_trait_item, &'hir TraitItem<'hir>, Node::TraitItem(n), n;
expect_impl_item, &'hir ImplItem<'hir>, Node::ImplItem(n), n;
expect_variant, &'hir Variant<'hir>, Node::Variant(n), n;
expect_field, &'hir FieldDef<'hir>, Node::Field(n), n;
expect_anon_const, &'hir AnonConst, Node::AnonConst(n), n;
expect_inline_const, &'hir ConstBlock, Node::ConstBlock(n), n;
expect_expr, &'hir Expr<'hir>, Node::Expr(n), n;
expect_expr_field, &'hir ExprField<'hir>, Node::ExprField(n), n;
expect_stmt, &'hir Stmt<'hir>, Node::Stmt(n), n;
expect_path_segment, &'hir PathSegment<'hir>, Node::PathSegment(n), n;
expect_ty, &'hir Ty<'hir>, Node::Ty(n), n;
expect_assoc_item_constraint, &'hir AssocItemConstraint<'hir>, Node::AssocItemConstraint(n), n;
expect_trait_ref, &'hir TraitRef<'hir>, Node::TraitRef(n), n;
expect_opaque_ty, &'hir OpaqueTy<'hir>, Node::OpaqueTy(n), n;
expect_pat, &'hir Pat<'hir>, Node::Pat(n), n;
expect_pat_field, &'hir PatField<'hir>, Node::PatField(n), n;
expect_arm, &'hir Arm<'hir>, Node::Arm(n), n;
expect_block, &'hir Block<'hir>, Node::Block(n), n;
expect_let_stmt, &'hir LetStmt<'hir>, Node::LetStmt(n), n;
expect_ctor, &'hir VariantData<'hir>, Node::Ctor(n), n;
expect_lifetime, &'hir Lifetime, Node::Lifetime(n), n;
expect_generic_param, &'hir GenericParam<'hir>, Node::GenericParam(n), n;
expect_crate, &'hir Mod<'hir>, Node::Crate(n), n;
expect_infer, &'hir InferArg, Node::Infer(n), n;
expect_closure, &'hir Closure<'hir>, Node::Expr(Expr { kind: ExprKind::Closure(n), .. }), n;
}
}
// Some nodes are used a lot. Make sure they don't unintentionally get bigger.
#[cfg(target_pointer_width = "64")]
mod size_asserts {
use rustc_data_structures::static_assert_size;
use super::*;
// tidy-alphabetical-start
static_assert_size!(Block<'_>, 48);
static_assert_size!(Body<'_>, 24);
static_assert_size!(Expr<'_>, 64);
static_assert_size!(ExprKind<'_>, 48);
static_assert_size!(FnDecl<'_>, 40);
static_assert_size!(ForeignItem<'_>, 88);
static_assert_size!(ForeignItemKind<'_>, 56);
static_assert_size!(GenericArg<'_>, 16);
static_assert_size!(GenericBound<'_>, 64);
static_assert_size!(Generics<'_>, 56);
static_assert_size!(Impl<'_>, 80);
static_assert_size!(ImplItem<'_>, 88);
static_assert_size!(ImplItemKind<'_>, 40);
static_assert_size!(Item<'_>, 88);
static_assert_size!(ItemKind<'_>, 56);
static_assert_size!(LetStmt<'_>, 64);
static_assert_size!(Param<'_>, 32);
static_assert_size!(Pat<'_>, 72);
static_assert_size!(Path<'_>, 40);
static_assert_size!(PathSegment<'_>, 48);
static_assert_size!(PatKind<'_>, 48);
static_assert_size!(QPath<'_>, 24);
static_assert_size!(Res, 12);
static_assert_size!(Stmt<'_>, 32);
static_assert_size!(StmtKind<'_>, 16);
static_assert_size!(TraitItem<'_>, 88);
static_assert_size!(TraitItemKind<'_>, 48);
static_assert_size!(Ty<'_>, 48);
static_assert_size!(TyKind<'_>, 32);
// tidy-alphabetical-end
}
fn debug_fn(f: impl Fn(&mut fmt::Formatter<'_>) -> fmt::Result) -> impl fmt::Debug {
struct DebugFn<F>(F);
impl<F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result> fmt::Debug for DebugFn<F> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
(self.0)(fmt)
}
}
DebugFn(f)
}