1 //! The Rust abstract syntax tree module.
3 //! This module contains common structures forming the language AST.
4 //! Two main entities in the module are [`Item`] (which represents an AST element with
5 //! additional metadata), and [`ItemKind`] (which represents a concrete type and contains
6 //! information specific to the type of the item).
8 //! Other module items worth mentioning:
9 //! - [`Ty`] and [`TyKind`]: A parsed Rust type.
10 //! - [`Expr`] and [`ExprKind`]: A parsed Rust expression.
11 //! - [`Pat`] and [`PatKind`]: A parsed Rust pattern. Patterns are often dual to expressions.
12 //! - [`Stmt`] and [`StmtKind`]: An executable action that does not return a value.
13 //! - [`FnDecl`], [`FnHeader`] and [`Param`]: Metadata associated with a function declaration.
14 //! - [`Generics`], [`GenericParam`], [`WhereClause`]: Metadata associated with generic parameters.
15 //! - [`EnumDef`] and [`Variant`]: Enum declaration.
16 //! - [`MetaItemLit`] and [`LitKind`]: Literal expressions.
17 //! - [`MacroDef`], [`MacStmtStyle`], [`MacCall`], [`MacDelimiter`]: Macro definition and invocation.
18 //! - [`Attribute`]: Metadata associated with item.
19 //! - [`UnOp`], [`BinOp`], and [`BinOpKind`]: Unary and binary operators.
21 pub use crate::util::parser::ExprPrecedence;
22 pub use GenericArgs::*;
23 pub use UnsafeSource::*;
26 use crate::token::{self, CommentKind, Delimiter};
27 use crate::tokenstream::{DelimSpan, LazyAttrTokenStream, TokenStream};
28 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
29 use rustc_data_structures::stack::ensure_sufficient_stack;
30 use rustc_data_structures::sync::Lrc;
31 use rustc_macros::HashStable_Generic;
32 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
33 use rustc_span::source_map::{respan, Spanned};
34 use rustc_span::symbol::{kw, sym, Ident, Symbol};
35 use rustc_span::{Span, DUMMY_SP};
36 use std::convert::TryFrom;
39 use thin_vec::{thin_vec, ThinVec};
41 /// A "Label" is an identifier of some point in sources,
42 /// e.g. in the following code:
50 /// `'outer` is a label.
51 #[derive(Clone, Encodable, Decodable, Copy, HashStable_Generic, Eq, PartialEq)]
56 impl fmt::Debug for Label {
57 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
58 write!(f, "label({:?})", self.ident)
62 /// A "Lifetime" is an annotation of the scope in which variable
63 /// can be used, e.g. `'a` in `&'a i32`.
64 #[derive(Clone, Encodable, Decodable, Copy, PartialEq, Eq)]
70 impl fmt::Debug for Lifetime {
71 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
72 write!(f, "lifetime({}: {})", self.id, self)
76 impl fmt::Display for Lifetime {
77 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
78 write!(f, "{}", self.ident.name)
82 /// A "Path" is essentially Rust's notion of a name.
84 /// It's represented as a sequence of identifiers,
85 /// along with a bunch of supporting information.
87 /// E.g., `std::cmp::PartialEq`.
88 #[derive(Clone, Encodable, Decodable, Debug)]
91 /// The segments in the path: the things separated by `::`.
92 /// Global paths begin with `kw::PathRoot`.
93 pub segments: ThinVec<PathSegment>,
94 pub tokens: Option<LazyAttrTokenStream>,
97 impl PartialEq<Symbol> for Path {
99 fn eq(&self, symbol: &Symbol) -> bool {
100 self.segments.len() == 1 && { self.segments[0].ident.name == *symbol }
104 impl<CTX: rustc_span::HashStableContext> HashStable<CTX> for Path {
105 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
106 self.segments.len().hash_stable(hcx, hasher);
107 for segment in &self.segments {
108 segment.ident.hash_stable(hcx, hasher);
114 /// Convert a span and an identifier to the corresponding
115 /// one-segment path.
116 pub fn from_ident(ident: Ident) -> Path {
117 Path { segments: thin_vec![PathSegment::from_ident(ident)], span: ident.span, tokens: None }
120 pub fn is_global(&self) -> bool {
121 !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
125 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
127 /// E.g., `std`, `String` or `Box<T>`.
128 #[derive(Clone, Encodable, Decodable, Debug)]
129 pub struct PathSegment {
130 /// The identifier portion of this path segment.
135 /// Type/lifetime parameters attached to this path. They come in
136 /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
137 /// `None` means that no parameter list is supplied (`Path`),
138 /// `Some` means that parameter list is supplied (`Path<X, Y>`)
139 /// but it can be empty (`Path<>`).
140 /// `P` is used as a size optimization for the common case with no parameters.
141 pub args: Option<P<GenericArgs>>,
145 pub fn from_ident(ident: Ident) -> Self {
146 PathSegment { ident, id: DUMMY_NODE_ID, args: None }
149 pub fn path_root(span: Span) -> Self {
150 PathSegment::from_ident(Ident::new(kw::PathRoot, span))
153 pub fn span(&self) -> Span {
155 Some(args) => self.ident.span.to(args.span()),
156 None => self.ident.span,
161 /// The arguments of a path segment.
163 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
164 #[derive(Clone, Encodable, Decodable, Debug)]
165 pub enum GenericArgs {
166 /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
167 AngleBracketed(AngleBracketedArgs),
168 /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
169 Parenthesized(ParenthesizedArgs),
173 pub fn is_angle_bracketed(&self) -> bool {
174 matches!(self, AngleBracketed(..))
177 pub fn span(&self) -> Span {
179 AngleBracketed(data) => data.span,
180 Parenthesized(data) => data.span,
185 /// Concrete argument in the sequence of generic args.
186 #[derive(Clone, Encodable, Decodable, Debug)]
187 pub enum GenericArg {
188 /// `'a` in `Foo<'a>`
190 /// `Bar` in `Foo<Bar>`
197 pub fn span(&self) -> Span {
199 GenericArg::Lifetime(lt) => lt.ident.span,
200 GenericArg::Type(ty) => ty.span,
201 GenericArg::Const(ct) => ct.value.span,
206 /// A path like `Foo<'a, T>`.
207 #[derive(Clone, Encodable, Decodable, Debug, Default)]
208 pub struct AngleBracketedArgs {
209 /// The overall span.
211 /// The comma separated parts in the `<...>`.
212 pub args: Vec<AngleBracketedArg>,
215 /// Either an argument for a parameter e.g., `'a`, `Vec<u8>`, `0`,
216 /// or a constraint on an associated item, e.g., `Item = String` or `Item: Bound`.
217 #[derive(Clone, Encodable, Decodable, Debug)]
218 pub enum AngleBracketedArg {
219 /// Argument for a generic parameter.
221 /// Constraint for an associated item.
222 Constraint(AssocConstraint),
225 impl AngleBracketedArg {
226 pub fn span(&self) -> Span {
228 AngleBracketedArg::Arg(arg) => arg.span(),
229 AngleBracketedArg::Constraint(constraint) => constraint.span,
234 impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
235 fn into(self) -> Option<P<GenericArgs>> {
236 Some(P(GenericArgs::AngleBracketed(self)))
240 impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
241 fn into(self) -> Option<P<GenericArgs>> {
242 Some(P(GenericArgs::Parenthesized(self)))
246 /// A path like `Foo(A, B) -> C`.
247 #[derive(Clone, Encodable, Decodable, Debug)]
248 pub struct ParenthesizedArgs {
256 pub inputs: Vec<P<Ty>>,
262 pub inputs_span: Span,
268 impl ParenthesizedArgs {
269 pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
274 .map(|input| AngleBracketedArg::Arg(GenericArg::Type(input)))
276 AngleBracketedArgs { span: self.inputs_span, args }
280 pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
282 /// A modifier on a bound, e.g., `?Trait` or `~const Trait`.
284 /// Negative bounds should also be handled here.
285 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
286 pub enum TraitBoundModifier {
298 // This parses but will be rejected during AST validation.
302 /// The AST represents all type param bounds as types.
303 /// `typeck::collect::compute_bounds` matches these against
304 /// the "special" built-in traits (see `middle::lang_items`) and
305 /// detects `Copy`, `Send` and `Sync`.
306 #[derive(Clone, Encodable, Decodable, Debug)]
307 pub enum GenericBound {
308 Trait(PolyTraitRef, TraitBoundModifier),
313 pub fn span(&self) -> Span {
315 GenericBound::Trait(t, ..) => t.span,
316 GenericBound::Outlives(l) => l.ident.span,
321 pub type GenericBounds = Vec<GenericBound>;
323 /// Specifies the enforced ordering for generic parameters. In the future,
324 /// if we wanted to relax this order, we could override `PartialEq` and
325 /// `PartialOrd`, to allow the kinds to be unordered.
326 #[derive(Hash, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
327 pub enum ParamKindOrd {
332 impl fmt::Display for ParamKindOrd {
333 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
335 ParamKindOrd::Lifetime => "lifetime".fmt(f),
336 ParamKindOrd::TypeOrConst => "type and const".fmt(f),
341 #[derive(Clone, Encodable, Decodable, Debug)]
342 pub enum GenericParamKind {
343 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
346 default: Option<P<Ty>>,
350 /// Span of the `const` keyword.
352 /// Optional default value for the const generic param
353 default: Option<AnonConst>,
357 #[derive(Clone, Encodable, Decodable, Debug)]
358 pub struct GenericParam {
362 pub bounds: GenericBounds,
363 pub is_placeholder: bool,
364 pub kind: GenericParamKind,
365 pub colon_span: Option<Span>,
369 pub fn span(&self) -> Span {
371 GenericParamKind::Lifetime | GenericParamKind::Type { default: None } => {
374 GenericParamKind::Type { default: Some(ty) } => self.ident.span.to(ty.span),
375 GenericParamKind::Const { kw_span, default: Some(default), .. } => {
376 kw_span.to(default.value.span)
378 GenericParamKind::Const { kw_span, default: None, ty } => kw_span.to(ty.span),
383 /// Represents lifetime, type and const parameters attached to a declaration of
384 /// a function, enum, trait, etc.
385 #[derive(Clone, Encodable, Decodable, Debug)]
386 pub struct Generics {
387 pub params: Vec<GenericParam>,
388 pub where_clause: WhereClause,
392 impl Default for Generics {
393 /// Creates an instance of `Generics`.
394 fn default() -> Generics {
395 Generics { params: Vec::new(), where_clause: Default::default(), span: DUMMY_SP }
399 /// A where-clause in a definition.
400 #[derive(Clone, Encodable, Decodable, Debug)]
401 pub struct WhereClause {
402 /// `true` if we ate a `where` token: this can happen
403 /// if we parsed no predicates (e.g. `struct Foo where {}`).
404 /// This allows us to pretty-print accurately.
405 pub has_where_token: bool,
406 pub predicates: Vec<WherePredicate>,
410 impl Default for WhereClause {
411 fn default() -> WhereClause {
412 WhereClause { has_where_token: false, predicates: Vec::new(), span: DUMMY_SP }
416 /// A single predicate in a where-clause.
417 #[derive(Clone, Encodable, Decodable, Debug)]
418 pub enum WherePredicate {
419 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
420 BoundPredicate(WhereBoundPredicate),
421 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
422 RegionPredicate(WhereRegionPredicate),
423 /// An equality predicate (unsupported).
424 EqPredicate(WhereEqPredicate),
427 impl WherePredicate {
428 pub fn span(&self) -> Span {
430 WherePredicate::BoundPredicate(p) => p.span,
431 WherePredicate::RegionPredicate(p) => p.span,
432 WherePredicate::EqPredicate(p) => p.span,
439 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
440 #[derive(Clone, Encodable, Decodable, Debug)]
441 pub struct WhereBoundPredicate {
443 /// Any generics from a `for` binding.
444 pub bound_generic_params: Vec<GenericParam>,
445 /// The type being bounded.
446 pub bounded_ty: P<Ty>,
447 /// Trait and lifetime bounds (`Clone + Send + 'static`).
448 pub bounds: GenericBounds,
451 /// A lifetime predicate.
453 /// E.g., `'a: 'b + 'c`.
454 #[derive(Clone, Encodable, Decodable, Debug)]
455 pub struct WhereRegionPredicate {
457 pub lifetime: Lifetime,
458 pub bounds: GenericBounds,
461 /// An equality predicate (unsupported).
464 #[derive(Clone, Encodable, Decodable, Debug)]
465 pub struct WhereEqPredicate {
471 #[derive(Clone, Encodable, Decodable, Debug)]
474 pub items: Vec<P<Item>>,
476 /// Must be equal to `CRATE_NODE_ID` after the crate root is expanded, but may hold
477 /// expansion placeholders or an unassigned value (`DUMMY_NODE_ID`) before that.
479 pub is_placeholder: bool,
482 /// Possible values inside of compile-time attribute lists.
484 /// E.g., the '..' in `#[name(..)]`.
485 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
486 pub enum NestedMetaItem {
487 /// A full MetaItem, for recursive meta items.
491 /// E.g., `"foo"`, `64`, `true`.
492 Literal(MetaItemLit),
495 /// A spanned compile-time attribute item.
497 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
498 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
499 pub struct MetaItem {
501 pub kind: MetaItemKind,
505 /// A compile-time attribute item.
507 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
508 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
509 pub enum MetaItemKind {
512 /// E.g., `test` as in `#[test]`.
516 /// E.g., `derive(..)` as in `#[derive(..)]`.
517 List(Vec<NestedMetaItem>),
518 /// Name value meta item.
520 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
521 NameValue(MetaItemLit),
524 /// A block (`{ .. }`).
526 /// E.g., `{ .. }` as in `fn foo() { .. }`.
527 #[derive(Clone, Encodable, Decodable, Debug)]
529 /// The statements in the block.
530 pub stmts: Vec<Stmt>,
532 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
533 pub rules: BlockCheckMode,
535 pub tokens: Option<LazyAttrTokenStream>,
536 /// The following *isn't* a parse error, but will cause multiple errors in following stages.
543 pub could_be_bare_literal: bool,
548 /// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
549 #[derive(Clone, Encodable, Decodable, Debug)]
554 pub tokens: Option<LazyAttrTokenStream>,
558 /// Attempt reparsing the pattern as a type.
559 /// This is intended for use by diagnostics.
560 pub fn to_ty(&self) -> Option<P<Ty>> {
561 let kind = match &self.kind {
562 // In a type expression `_` is an inference variable.
563 PatKind::Wild => TyKind::Infer,
564 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
565 PatKind::Ident(BindingAnnotation::NONE, ident, None) => {
566 TyKind::Path(None, Path::from_ident(*ident))
568 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
569 PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
570 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
571 PatKind::Ref(pat, mutbl) => {
572 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
574 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
575 // when `P` can be reparsed as a type `T`.
576 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
577 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
578 // assuming `T0` to `Tn` are all syntactically valid as types.
579 PatKind::Tuple(pats) => {
580 let mut tys = Vec::with_capacity(pats.len());
581 // FIXME(#48994) - could just be collected into an Option<Vec>
583 tys.push(pat.to_ty()?);
590 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
593 /// Walk top-down and call `it` in each place where a pattern occurs
594 /// starting with the root pattern `walk` is called on. If `it` returns
595 /// false then we will descend no further but siblings will be processed.
596 pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
602 // Walk into the pattern associated with `Ident` (if any).
603 PatKind::Ident(_, _, Some(p)) => p.walk(it),
605 // Walk into each field of struct.
606 PatKind::Struct(_, _, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
608 // Sequence of patterns.
609 PatKind::TupleStruct(_, _, s)
612 | PatKind::Or(s) => s.iter().for_each(|p| p.walk(it)),
614 // Trivial wrappers over inner patterns.
615 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
617 // These patterns do not contain subpatterns, skip.
624 | PatKind::MacCall(_) => {}
628 /// Is this a `..` pattern?
629 pub fn is_rest(&self) -> bool {
630 matches!(self.kind, PatKind::Rest)
634 /// A single field in a struct pattern.
636 /// Patterns like the fields of `Foo { x, ref y, ref mut z }`
637 /// are treated the same as `x: x, y: ref y, z: ref mut z`,
638 /// except when `is_shorthand` is true.
639 #[derive(Clone, Encodable, Decodable, Debug)]
640 pub struct PatField {
641 /// The identifier for the field.
643 /// The pattern the field is destructured to.
645 pub is_shorthand: bool,
649 pub is_placeholder: bool,
652 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
653 #[derive(Encodable, Decodable, HashStable_Generic)]
659 impl From<bool> for ByRef {
660 fn from(b: bool) -> ByRef {
668 /// Explicit binding annotations given in the HIR for a binding. Note
669 /// that this is not the final binding *mode* that we infer after type
671 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
672 #[derive(Encodable, Decodable, HashStable_Generic)]
673 pub struct BindingAnnotation(pub ByRef, pub Mutability);
675 impl BindingAnnotation {
676 pub const NONE: Self = Self(ByRef::No, Mutability::Not);
677 pub const REF: Self = Self(ByRef::Yes, Mutability::Not);
678 pub const MUT: Self = Self(ByRef::No, Mutability::Mut);
679 pub const REF_MUT: Self = Self(ByRef::Yes, Mutability::Mut);
681 pub fn prefix_str(self) -> &'static str {
686 Self::REF_MUT => "ref mut ",
691 #[derive(Clone, Encodable, Decodable, Debug)]
694 Included(RangeSyntax),
699 #[derive(Clone, Encodable, Decodable, Debug)]
700 pub enum RangeSyntax {
707 /// All the different flavors of pattern that Rust recognizes.
708 #[derive(Clone, Encodable, Decodable, Debug)]
710 /// Represents a wildcard pattern (`_`).
713 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
714 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
715 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
716 /// during name resolution.
717 Ident(BindingAnnotation, Ident, Option<P<Pat>>),
719 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
720 /// The `bool` is `true` in the presence of a `..`.
721 Struct(Option<P<QSelf>>, Path, Vec<PatField>, /* recovered */ bool),
723 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
724 TupleStruct(Option<P<QSelf>>, Path, Vec<P<Pat>>),
726 /// An or-pattern `A | B | C`.
727 /// Invariant: `pats.len() >= 2`.
730 /// A possibly qualified path pattern.
731 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
732 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
733 /// only legally refer to associated constants.
734 Path(Option<P<QSelf>>, Path),
736 /// A tuple pattern (`(a, b)`).
742 /// A reference pattern (e.g., `&mut (a, b)`).
743 Ref(P<Pat>, Mutability),
748 /// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
749 Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
751 /// A slice pattern `[a, b, c]`.
754 /// A rest pattern `..`.
756 /// Syntactically it is valid anywhere.
758 /// Semantically however, it only has meaning immediately inside:
759 /// - a slice pattern: `[a, .., b]`,
760 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
761 /// - a tuple pattern: `(a, .., b)`,
762 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
764 /// In all of these cases, an additional restriction applies,
765 /// only one rest pattern may occur in the pattern sequences.
768 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
771 /// A macro pattern; pre-expansion.
775 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
776 #[derive(HashStable_Generic, Encodable, Decodable)]
777 pub enum Mutability {
778 // N.B. Order is deliberate, so that Not < Mut
784 pub fn invert(self) -> Self {
786 Mutability::Mut => Mutability::Not,
787 Mutability::Not => Mutability::Mut,
791 /// Returns `""` (empty string) or `"mut "` depending on the mutability.
792 pub fn prefix_str(self) -> &'static str {
794 Mutability::Mut => "mut ",
795 Mutability::Not => "",
799 /// Returns `"&"` or `"&mut "` depending on the mutability.
800 pub fn ref_prefix_str(self) -> &'static str {
802 Mutability::Not => "&",
803 Mutability::Mut => "&mut ",
807 /// Returns `""` (empty string) or `"mutably "` depending on the mutability.
808 pub fn mutably_str(self) -> &'static str {
810 Mutability::Not => "",
811 Mutability::Mut => "mutably ",
815 /// Return `true` if self is mutable
816 pub fn is_mut(self) -> bool {
817 matches!(self, Self::Mut)
820 /// Return `true` if self is **not** mutable
821 pub fn is_not(self) -> bool {
822 matches!(self, Self::Not)
826 /// The kind of borrow in an `AddrOf` expression,
827 /// e.g., `&place` or `&raw const place`.
828 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
829 #[derive(Encodable, Decodable, HashStable_Generic)]
830 pub enum BorrowKind {
831 /// A normal borrow, `&$expr` or `&mut $expr`.
832 /// The resulting type is either `&'a T` or `&'a mut T`
833 /// where `T = typeof($expr)` and `'a` is some lifetime.
835 /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
836 /// The resulting type is either `*const T` or `*mut T`
837 /// where `T = typeof($expr)`.
841 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
843 /// The `+` operator (addition)
845 /// The `-` operator (subtraction)
847 /// The `*` operator (multiplication)
849 /// The `/` operator (division)
851 /// The `%` operator (modulus)
853 /// The `&&` operator (logical and)
855 /// The `||` operator (logical or)
857 /// The `^` operator (bitwise xor)
859 /// The `&` operator (bitwise and)
861 /// The `|` operator (bitwise or)
863 /// The `<<` operator (shift left)
865 /// The `>>` operator (shift right)
867 /// The `==` operator (equality)
869 /// The `<` operator (less than)
871 /// The `<=` operator (less than or equal to)
873 /// The `!=` operator (not equal to)
875 /// The `>=` operator (greater than or equal to)
877 /// The `>` operator (greater than)
882 pub fn to_string(&self) -> &'static str {
905 pub fn lazy(&self) -> bool {
906 matches!(self, BinOpKind::And | BinOpKind::Or)
909 pub fn is_comparison(&self) -> bool {
911 // Note for developers: please keep this as is;
912 // we want compilation to fail if another variant is added.
914 Eq | Lt | Le | Ne | Gt | Ge => true,
915 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
920 pub type BinOp = Spanned<BinOpKind>;
924 /// Note that `&data` is not an operator, it's an `AddrOf` expression.
925 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
927 /// The `*` operator for dereferencing
929 /// The `!` operator for logical inversion
931 /// The `-` operator for negation
936 pub fn to_string(op: UnOp) -> &'static str {
946 #[derive(Clone, Encodable, Decodable, Debug)]
954 pub fn has_trailing_semicolon(&self) -> bool {
956 StmtKind::Semi(_) => true,
957 StmtKind::MacCall(mac) => matches!(mac.style, MacStmtStyle::Semicolon),
962 /// Converts a parsed `Stmt` to a `Stmt` with
963 /// a trailing semicolon.
965 /// This only modifies the parsed AST struct, not the attached
966 /// `LazyAttrTokenStream`. The parser is responsible for calling
967 /// `ToAttrTokenStream::add_trailing_semi` when there is actually
968 /// a semicolon in the tokenstream.
969 pub fn add_trailing_semicolon(mut self) -> Self {
970 self.kind = match self.kind {
971 StmtKind::Expr(expr) => StmtKind::Semi(expr),
972 StmtKind::MacCall(mac) => {
973 StmtKind::MacCall(mac.map(|MacCallStmt { mac, style: _, attrs, tokens }| {
974 MacCallStmt { mac, style: MacStmtStyle::Semicolon, attrs, tokens }
983 pub fn is_item(&self) -> bool {
984 matches!(self.kind, StmtKind::Item(_))
987 pub fn is_expr(&self) -> bool {
988 matches!(self.kind, StmtKind::Expr(_))
992 #[derive(Clone, Encodable, Decodable, Debug)]
994 /// A local (let) binding.
996 /// An item definition.
998 /// Expr without trailing semi-colon.
1000 /// Expr with a trailing semi-colon.
1002 /// Just a trailing semi-colon.
1005 MacCall(P<MacCallStmt>),
1008 #[derive(Clone, Encodable, Decodable, Debug)]
1009 pub struct MacCallStmt {
1010 pub mac: P<MacCall>,
1011 pub style: MacStmtStyle,
1013 pub tokens: Option<LazyAttrTokenStream>,
1016 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
1017 pub enum MacStmtStyle {
1018 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
1019 /// `foo!(...);`, `foo![...];`).
1021 /// The macro statement had braces (e.g., `foo! { ... }`).
1023 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
1024 /// `foo!(...)`). All of these will end up being converted into macro
1029 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
1030 #[derive(Clone, Encodable, Decodable, Debug)]
1034 pub ty: Option<P<Ty>>,
1035 pub kind: LocalKind,
1038 pub tokens: Option<LazyAttrTokenStream>,
1041 #[derive(Clone, Encodable, Decodable, Debug)]
1042 pub enum LocalKind {
1043 /// Local declaration.
1044 /// Example: `let x;`
1046 /// Local declaration with an initializer.
1047 /// Example: `let x = y;`
1049 /// Local declaration with an initializer and an `else` clause.
1050 /// Example: `let Some(x) = y else { return };`
1051 InitElse(P<Expr>, P<Block>),
1055 pub fn init(&self) -> Option<&Expr> {
1058 Self::Init(i) | Self::InitElse(i, _) => Some(i),
1062 pub fn init_else_opt(&self) -> Option<(&Expr, Option<&Block>)> {
1065 Self::Init(init) => Some((init, None)),
1066 Self::InitElse(init, els) => Some((init, Some(els))),
1071 /// An arm of a 'match'.
1073 /// E.g., `0..=10 => { println!("match!") }` as in
1077 /// 0..=10 => { println!("match!") },
1078 /// _ => { println!("no match!") },
1081 #[derive(Clone, Encodable, Decodable, Debug)]
1084 /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
1086 /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
1087 pub guard: Option<P<Expr>>,
1092 pub is_placeholder: bool,
1095 /// A single field in a struct expression, e.g. `x: value` and `y` in `Foo { x: value, y }`.
1096 #[derive(Clone, Encodable, Decodable, Debug)]
1097 pub struct ExprField {
1103 pub is_shorthand: bool,
1104 pub is_placeholder: bool,
1107 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1108 pub enum BlockCheckMode {
1110 Unsafe(UnsafeSource),
1113 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1114 pub enum UnsafeSource {
1119 /// A constant (expression) that's not an item or associated item,
1120 /// but needs its own `DefId` for type-checking, const-eval, etc.
1121 /// These are usually found nested inside types (e.g., array lengths)
1122 /// or expressions (e.g., repeat counts), and also used to define
1123 /// explicit discriminant values for enum variants.
1124 #[derive(Clone, Encodable, Decodable, Debug)]
1125 pub struct AnonConst {
1131 #[derive(Clone, Encodable, Decodable, Debug)]
1137 pub tokens: Option<LazyAttrTokenStream>,
1141 /// Is this expr either `N`, or `{ N }`.
1143 /// If this is not the case, name resolution does not resolve `N` when using
1144 /// `min_const_generics` as more complex expressions are not supported.
1145 pub fn is_potential_trivial_const_param(&self) -> bool {
1146 let this = if let ExprKind::Block(block, None) = &self.kind
1147 && block.stmts.len() == 1
1148 && let StmtKind::Expr(expr) = &block.stmts[0].kind
1155 if let ExprKind::Path(None, path) = &this.kind
1156 && path.segments.len() == 1
1157 && path.segments[0].args.is_none()
1165 pub fn to_bound(&self) -> Option<GenericBound> {
1167 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1168 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1169 TraitBoundModifier::None,
1175 pub fn peel_parens(&self) -> &Expr {
1176 let mut expr = self;
1177 while let ExprKind::Paren(inner) = &expr.kind {
1183 /// Attempts to reparse as `Ty` (for diagnostic purposes).
1184 pub fn to_ty(&self) -> Option<P<Ty>> {
1185 let kind = match &self.kind {
1186 // Trivial conversions.
1187 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1188 ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
1190 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1192 ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
1193 expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
1196 ExprKind::Repeat(expr, expr_len) => {
1197 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1200 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1202 ExprKind::Tup(exprs) => {
1203 let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
1207 // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
1208 // then type of result is trait object.
1209 // Otherwise we don't assume the result type.
1210 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1211 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1212 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1218 ExprKind::Underscore => TyKind::Infer,
1220 // This expression doesn't look like a type syntactically.
1224 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
1227 pub fn precedence(&self) -> ExprPrecedence {
1229 ExprKind::Box(_) => ExprPrecedence::Box,
1230 ExprKind::Array(_) => ExprPrecedence::Array,
1231 ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
1232 ExprKind::Call(..) => ExprPrecedence::Call,
1233 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1234 ExprKind::Tup(_) => ExprPrecedence::Tup,
1235 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1236 ExprKind::Unary(..) => ExprPrecedence::Unary,
1237 ExprKind::Lit(_) | ExprKind::IncludedBytes(..) => ExprPrecedence::Lit,
1238 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1239 ExprKind::Let(..) => ExprPrecedence::Let,
1240 ExprKind::If(..) => ExprPrecedence::If,
1241 ExprKind::While(..) => ExprPrecedence::While,
1242 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1243 ExprKind::Loop(..) => ExprPrecedence::Loop,
1244 ExprKind::Match(..) => ExprPrecedence::Match,
1245 ExprKind::Closure(..) => ExprPrecedence::Closure,
1246 ExprKind::Block(..) => ExprPrecedence::Block,
1247 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1248 ExprKind::Async(..) => ExprPrecedence::Async,
1249 ExprKind::Await(..) => ExprPrecedence::Await,
1250 ExprKind::Assign(..) => ExprPrecedence::Assign,
1251 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1252 ExprKind::Field(..) => ExprPrecedence::Field,
1253 ExprKind::Index(..) => ExprPrecedence::Index,
1254 ExprKind::Range(..) => ExprPrecedence::Range,
1255 ExprKind::Underscore => ExprPrecedence::Path,
1256 ExprKind::Path(..) => ExprPrecedence::Path,
1257 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1258 ExprKind::Break(..) => ExprPrecedence::Break,
1259 ExprKind::Continue(..) => ExprPrecedence::Continue,
1260 ExprKind::Ret(..) => ExprPrecedence::Ret,
1261 ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
1262 ExprKind::MacCall(..) => ExprPrecedence::Mac,
1263 ExprKind::Struct(..) => ExprPrecedence::Struct,
1264 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1265 ExprKind::Paren(..) => ExprPrecedence::Paren,
1266 ExprKind::Try(..) => ExprPrecedence::Try,
1267 ExprKind::Yield(..) => ExprPrecedence::Yield,
1268 ExprKind::Yeet(..) => ExprPrecedence::Yeet,
1269 ExprKind::Err => ExprPrecedence::Err,
1273 pub fn take(&mut self) -> Self {
1278 kind: ExprKind::Err,
1280 attrs: AttrVec::new(),
1286 /// To a first-order approximation, is this a pattern?
1287 pub fn is_approximately_pattern(&self) -> bool {
1288 match &self.peel_parens().kind {
1290 | ExprKind::Array(_)
1291 | ExprKind::Call(_, _)
1294 | ExprKind::Range(_, _, _)
1295 | ExprKind::Underscore
1296 | ExprKind::Path(_, _)
1297 | ExprKind::Struct(_) => true,
1303 #[derive(Clone, Encodable, Decodable, Debug)]
1304 pub struct Closure {
1305 pub binder: ClosureBinder,
1306 pub capture_clause: CaptureBy,
1307 pub asyncness: Async,
1308 pub movability: Movability,
1309 pub fn_decl: P<FnDecl>,
1311 /// The span of the argument block `|...|`.
1312 pub fn_decl_span: Span,
1315 /// Limit types of a range (inclusive or exclusive)
1316 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
1317 pub enum RangeLimits {
1318 /// Inclusive at the beginning, exclusive at the end
1320 /// Inclusive at the beginning and end
1324 /// A method call (e.g. `x.foo::<Bar, Baz>(a, b, c)`).
1325 #[derive(Clone, Encodable, Decodable, Debug)]
1326 pub struct MethodCall {
1327 /// The method name and its generic arguments, e.g. `foo::<Bar, Baz>`.
1328 pub seg: PathSegment,
1329 /// The receiver, e.g. `x`.
1330 pub receiver: P<Expr>,
1331 /// The arguments, e.g. `a, b, c`.
1332 pub args: Vec<P<Expr>>,
1333 /// The span of the function, without the dot and receiver e.g. `foo::<Bar,
1338 #[derive(Clone, Encodable, Decodable, Debug)]
1339 pub enum StructRest {
1344 /// No trailing `..` or expression.
1348 #[derive(Clone, Encodable, Decodable, Debug)]
1349 pub struct StructExpr {
1350 pub qself: Option<P<QSelf>>,
1352 pub fields: Vec<ExprField>,
1353 pub rest: StructRest,
1356 #[derive(Clone, Encodable, Decodable, Debug)]
1358 /// A `box x` expression.
1360 /// An array (`[a, b, c, d]`)
1361 Array(Vec<P<Expr>>),
1362 /// Allow anonymous constants from an inline `const` block
1363 ConstBlock(AnonConst),
1366 /// The first field resolves to the function itself,
1367 /// and the second field is the list of arguments.
1368 /// This also represents calling the constructor of
1369 /// tuple-like ADTs such as tuple structs and enum variants.
1370 Call(P<Expr>, Vec<P<Expr>>),
1371 /// A method call (e.g. `x.foo::<Bar, Baz>(a, b, c)`).
1372 MethodCall(Box<MethodCall>),
1373 /// A tuple (e.g., `(a, b, c, d)`).
1375 /// A binary operation (e.g., `a + b`, `a * b`).
1376 Binary(BinOp, P<Expr>, P<Expr>),
1377 /// A unary operation (e.g., `!x`, `*x`).
1378 Unary(UnOp, P<Expr>),
1379 /// A literal (e.g., `1`, `"foo"`).
1381 /// A cast (e.g., `foo as f64`).
1382 Cast(P<Expr>, P<Ty>),
1383 /// A type ascription (e.g., `42: usize`).
1384 Type(P<Expr>, P<Ty>),
1385 /// A `let pat = expr` expression that is only semantically allowed in the condition
1386 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1388 /// `Span` represents the whole `let pat = expr` statement.
1389 Let(P<Pat>, P<Expr>, Span),
1390 /// An `if` block, with an optional `else` block.
1392 /// `if expr { block } else { expr }`
1393 If(P<Expr>, P<Block>, Option<P<Expr>>),
1394 /// A while loop, with an optional label.
1396 /// `'label: while expr { block }`
1397 While(P<Expr>, P<Block>, Option<Label>),
1398 /// A `for` loop, with an optional label.
1400 /// `'label: for pat in expr { block }`
1402 /// This is desugared to a combination of `loop` and `match` expressions.
1403 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1404 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1406 /// `'label: loop { block }`
1407 Loop(P<Block>, Option<Label>, Span),
1408 /// A `match` block.
1409 Match(P<Expr>, Vec<Arm>),
1410 /// A closure (e.g., `move |a, b, c| a + b + c`).
1411 Closure(Box<Closure>),
1412 /// A block (`'label: { ... }`).
1413 Block(P<Block>, Option<Label>),
1414 /// An async block (`async move { ... }`).
1416 /// The `NodeId` is the `NodeId` for the closure that results from
1417 /// desugaring an async block, just like the NodeId field in the
1418 /// `Async::Yes` variant. This is necessary in order to create a def for the
1419 /// closure which can be used as a parent of any child defs. Defs
1420 /// created during lowering cannot be made the parent of any other
1421 /// preexisting defs.
1422 Async(CaptureBy, NodeId, P<Block>),
1423 /// An await expression (`my_future.await`).
1426 /// A try block (`try { ... }`).
1429 /// An assignment (`a = foo()`).
1430 /// The `Span` argument is the span of the `=` token.
1431 Assign(P<Expr>, P<Expr>, Span),
1432 /// An assignment with an operator.
1435 AssignOp(BinOp, P<Expr>, P<Expr>),
1436 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1437 Field(P<Expr>, Ident),
1438 /// An indexing operation (e.g., `foo[2]`).
1439 Index(P<Expr>, P<Expr>),
1440 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assignment).
1441 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1442 /// An underscore, used in destructuring assignment to ignore a value.
1445 /// Variable reference, possibly containing `::` and/or type
1446 /// parameters (e.g., `foo::bar::<baz>`).
1448 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1449 Path(Option<P<QSelf>>, Path),
1451 /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
1452 AddrOf(BorrowKind, Mutability, P<Expr>),
1453 /// A `break`, with an optional label to break, and an optional expression.
1454 Break(Option<Label>, Option<P<Expr>>),
1455 /// A `continue`, with an optional label.
1456 Continue(Option<Label>),
1457 /// A `return`, with an optional value to be returned.
1458 Ret(Option<P<Expr>>),
1460 /// Output of the `asm!()` macro.
1461 InlineAsm(P<InlineAsm>),
1463 /// A macro invocation; pre-expansion.
1464 MacCall(P<MacCall>),
1466 /// A struct literal expression.
1468 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
1469 Struct(P<StructExpr>),
1471 /// An array literal constructed from one repeated element.
1473 /// E.g., `[1; 5]`. The expression is the element to be
1474 /// repeated; the constant is the number of times to repeat it.
1475 Repeat(P<Expr>, AnonConst),
1477 /// No-op: used solely so we can pretty-print faithfully.
1480 /// A try expression (`expr?`).
1483 /// A `yield`, with an optional value to be yielded.
1484 Yield(Option<P<Expr>>),
1486 /// A `do yeet` (aka `throw`/`fail`/`bail`/`raise`/whatever),
1487 /// with an optional value to be returned.
1488 Yeet(Option<P<Expr>>),
1490 /// Bytes included via `include_bytes!`
1491 /// Added for optimization purposes to avoid the need to escape
1492 /// large binary blobs - should always behave like [`ExprKind::Lit`]
1493 /// with a `ByteStr` literal.
1494 IncludedBytes(Lrc<[u8]>),
1496 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1500 /// The explicit `Self` type in a "qualified path". The actual
1501 /// path, including the trait and the associated item, is stored
1502 /// separately. `position` represents the index of the associated
1503 /// item qualified with this `Self` type.
1505 /// ```ignore (only-for-syntax-highlight)
1506 /// <Vec<T> as a::b::Trait>::AssociatedItem
1507 /// ^~~~~ ~~~~~~~~~~~~~~^
1510 /// <Vec<T>>::AssociatedItem
1514 #[derive(Clone, Encodable, Decodable, Debug)]
1518 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1519 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1520 /// 0`, this is an empty span.
1521 pub path_span: Span,
1522 pub position: usize,
1525 /// A capture clause used in closures and `async` blocks.
1526 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1527 pub enum CaptureBy {
1528 /// `move |x| y + x`.
1530 /// `move` keyword was not specified.
1534 /// The movability of a generator / closure literal:
1535 /// whether a generator contains self-references, causing it to be `!Unpin`.
1536 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
1537 #[derive(HashStable_Generic)]
1538 pub enum Movability {
1539 /// May contain self-references, `!Unpin`.
1541 /// Must not contain self-references, `Unpin`.
1545 /// Closure lifetime binder, `for<'a, 'b>` in `for<'a, 'b> |_: &'a (), _: &'b ()|`.
1546 #[derive(Clone, Encodable, Decodable, Debug)]
1547 pub enum ClosureBinder {
1548 /// The binder is not present, all closure lifetimes are inferred.
1550 /// The binder is present.
1552 /// Span of the whole `for<>` clause
1555 /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
1556 /// ^^^^^^^^^^^ -- this
1560 /// Lifetimes in the `for<>` closure
1563 /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
1566 generic_params: P<[GenericParam]>,
1570 /// Represents a macro invocation. The `path` indicates which macro
1571 /// is being invoked, and the `args` are arguments passed to it.
1572 #[derive(Clone, Encodable, Decodable, Debug)]
1573 pub struct MacCall {
1575 pub args: P<DelimArgs>,
1576 pub prior_type_ascription: Option<(Span, bool)>,
1580 pub fn span(&self) -> Span {
1581 self.path.span.to(self.args.dspan.entire())
1585 /// Arguments passed to an attribute macro.
1586 #[derive(Clone, Encodable, Decodable, Debug)]
1588 /// No arguments: `#[attr]`.
1590 /// Delimited arguments: `#[attr()/[]/{}]`.
1591 Delimited(DelimArgs),
1592 /// Arguments of a key-value attribute: `#[attr = "value"]`.
1594 /// Span of the `=` token.
1601 // The RHS of an `AttrArgs::Eq` starts out as an expression. Once macro
1602 // expansion is completed, all cases end up either as a meta item literal,
1603 // which is the form used after lowering to HIR, or as an error.
1604 #[derive(Clone, Encodable, Decodable, Debug)]
1605 pub enum AttrArgsEq {
1611 pub fn span(&self) -> Option<Span> {
1613 AttrArgs::Empty => None,
1614 AttrArgs::Delimited(args) => Some(args.dspan.entire()),
1615 AttrArgs::Eq(eq_span, AttrArgsEq::Ast(expr)) => Some(eq_span.to(expr.span)),
1616 AttrArgs::Eq(_, AttrArgsEq::Hir(lit)) => {
1617 unreachable!("in literal form when getting span: {:?}", lit);
1622 /// Tokens inside the delimiters or after `=`.
1623 /// Proc macros see these tokens, for example.
1624 pub fn inner_tokens(&self) -> TokenStream {
1626 AttrArgs::Empty => TokenStream::default(),
1627 AttrArgs::Delimited(args) => args.tokens.clone(),
1628 AttrArgs::Eq(_, AttrArgsEq::Ast(expr)) => TokenStream::from_ast(expr),
1629 AttrArgs::Eq(_, AttrArgsEq::Hir(lit)) => {
1630 unreachable!("in literal form when getting inner tokens: {:?}", lit)
1636 impl<CTX> HashStable<CTX> for AttrArgs
1638 CTX: crate::HashStableContext,
1640 fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
1641 mem::discriminant(self).hash_stable(ctx, hasher);
1643 AttrArgs::Empty => {}
1644 AttrArgs::Delimited(args) => args.hash_stable(ctx, hasher),
1645 AttrArgs::Eq(_eq_span, AttrArgsEq::Ast(expr)) => {
1646 unreachable!("hash_stable {:?}", expr);
1648 AttrArgs::Eq(eq_span, AttrArgsEq::Hir(lit)) => {
1649 eq_span.hash_stable(ctx, hasher);
1650 lit.hash_stable(ctx, hasher);
1656 /// Delimited arguments, as used in `#[attr()/[]/{}]` or `mac!()/[]/{}`.
1657 #[derive(Clone, Encodable, Decodable, Debug)]
1658 pub struct DelimArgs {
1659 pub dspan: DelimSpan,
1660 pub delim: MacDelimiter,
1661 pub tokens: TokenStream,
1665 /// Whether a macro with these arguments needs a semicolon
1666 /// when used as a standalone item or statement.
1667 pub fn need_semicolon(&self) -> bool {
1668 !matches!(self, DelimArgs { delim: MacDelimiter::Brace, .. })
1672 impl<CTX> HashStable<CTX> for DelimArgs
1674 CTX: crate::HashStableContext,
1676 fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
1677 let DelimArgs { dspan, delim, tokens } = self;
1678 dspan.hash_stable(ctx, hasher);
1679 delim.hash_stable(ctx, hasher);
1680 tokens.hash_stable(ctx, hasher);
1684 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
1685 pub enum MacDelimiter {
1692 pub fn to_token(self) -> Delimiter {
1694 MacDelimiter::Parenthesis => Delimiter::Parenthesis,
1695 MacDelimiter::Bracket => Delimiter::Bracket,
1696 MacDelimiter::Brace => Delimiter::Brace,
1700 pub fn from_token(delim: Delimiter) -> Option<MacDelimiter> {
1702 Delimiter::Parenthesis => Some(MacDelimiter::Parenthesis),
1703 Delimiter::Bracket => Some(MacDelimiter::Bracket),
1704 Delimiter::Brace => Some(MacDelimiter::Brace),
1705 Delimiter::Invisible => None,
1710 /// Represents a macro definition.
1711 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1712 pub struct MacroDef {
1713 pub body: P<DelimArgs>,
1714 /// `true` if macro was defined with `macro_rules`.
1715 pub macro_rules: bool,
1718 #[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
1719 #[derive(HashStable_Generic)]
1721 /// A regular string, like `"foo"`.
1723 /// A raw string, like `r##"foo"##`.
1725 /// The value is the number of `#` symbols used.
1729 /// A literal in a meta item.
1730 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1731 pub struct MetaItemLit {
1732 /// The original literal token as written in source code.
1733 pub token_lit: token::Lit,
1734 /// The "semantic" representation of the literal lowered from the original tokens.
1735 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1740 /// Same as `Lit`, but restricted to string literals.
1741 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1743 /// The original literal token as written in source code.
1744 pub style: StrStyle,
1746 pub suffix: Option<Symbol>,
1748 /// The unescaped "semantic" representation of the literal lowered from the original token.
1749 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1750 pub symbol_unescaped: Symbol,
1754 pub fn as_token_lit(&self) -> token::Lit {
1755 let token_kind = match self.style {
1756 StrStyle::Cooked => token::Str,
1757 StrStyle::Raw(n) => token::StrRaw(n),
1759 token::Lit::new(token_kind, self.symbol, self.suffix)
1763 /// Type of the integer literal based on provided suffix.
1764 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1765 #[derive(HashStable_Generic)]
1766 pub enum LitIntType {
1775 /// Type of the float literal based on provided suffix.
1776 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1777 #[derive(HashStable_Generic)]
1778 pub enum LitFloatType {
1779 /// A float literal with a suffix (`1f32` or `1E10f32`).
1781 /// A float literal without a suffix (`1.0 or 1.0E10`).
1785 /// This type is used within both `ast::MetaItemLit` and `hir::Lit`.
1787 /// Note that the entire literal (including the suffix) is considered when
1788 /// deciding the `LitKind`. This means that float literals like `1f32` are
1789 /// classified by this type as `Float`. This is different to `token::LitKind`
1790 /// which does *not* consider the suffix.
1791 #[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
1793 /// A string literal (`"foo"`). The symbol is unescaped, and so may differ
1794 /// from the original token's symbol.
1795 Str(Symbol, StrStyle),
1796 /// A byte string (`b"foo"`).
1798 /// A byte char (`b'f'`).
1800 /// A character literal (`'a'`).
1802 /// An integer literal (`1`).
1803 Int(u128, LitIntType),
1804 /// A float literal (`1.0`, `1f64` or `1E10f64`). The pre-suffix part is
1805 /// stored as a symbol rather than `f64` so that `LitKind` can impl `Eq`
1807 Float(Symbol, LitFloatType),
1808 /// A boolean literal (`true`, `false`).
1810 /// Placeholder for a literal that wasn't well-formed in some way.
1815 /// Returns `true` if this literal is a string.
1816 pub fn is_str(&self) -> bool {
1817 matches!(self, LitKind::Str(..))
1820 /// Returns `true` if this literal is byte literal string.
1821 pub fn is_bytestr(&self) -> bool {
1822 matches!(self, LitKind::ByteStr(_))
1825 /// Returns `true` if this is a numeric literal.
1826 pub fn is_numeric(&self) -> bool {
1827 matches!(self, LitKind::Int(..) | LitKind::Float(..))
1830 /// Returns `true` if this literal has no suffix.
1831 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1832 pub fn is_unsuffixed(&self) -> bool {
1836 /// Returns `true` if this literal has a suffix.
1837 pub fn is_suffixed(&self) -> bool {
1839 // suffixed variants
1840 LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
1841 | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
1842 // unsuffixed variants
1844 | LitKind::ByteStr(..)
1847 | LitKind::Int(_, LitIntType::Unsuffixed)
1848 | LitKind::Float(_, LitFloatType::Unsuffixed)
1850 | LitKind::Err => false,
1855 // N.B., If you change this, you'll probably want to change the corresponding
1856 // type structure in `middle/ty.rs` as well.
1857 #[derive(Clone, Encodable, Decodable, Debug)]
1860 pub mutbl: Mutability,
1863 /// Represents a function's signature in a trait declaration,
1864 /// trait implementation, or free function.
1865 #[derive(Clone, Encodable, Decodable, Debug)]
1867 pub header: FnHeader,
1868 pub decl: P<FnDecl>,
1872 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1873 #[derive(Encodable, Decodable, HashStable_Generic)]
1880 pub fn name_str(self) -> &'static str {
1882 FloatTy::F32 => "f32",
1883 FloatTy::F64 => "f64",
1887 pub fn name(self) -> Symbol {
1889 FloatTy::F32 => sym::f32,
1890 FloatTy::F64 => sym::f64,
1895 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1896 #[derive(Encodable, Decodable, HashStable_Generic)]
1907 pub fn name_str(&self) -> &'static str {
1909 IntTy::Isize => "isize",
1911 IntTy::I16 => "i16",
1912 IntTy::I32 => "i32",
1913 IntTy::I64 => "i64",
1914 IntTy::I128 => "i128",
1918 pub fn name(&self) -> Symbol {
1920 IntTy::Isize => sym::isize,
1921 IntTy::I8 => sym::i8,
1922 IntTy::I16 => sym::i16,
1923 IntTy::I32 => sym::i32,
1924 IntTy::I64 => sym::i64,
1925 IntTy::I128 => sym::i128,
1930 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
1931 #[derive(Encodable, Decodable, HashStable_Generic)]
1942 pub fn name_str(&self) -> &'static str {
1944 UintTy::Usize => "usize",
1946 UintTy::U16 => "u16",
1947 UintTy::U32 => "u32",
1948 UintTy::U64 => "u64",
1949 UintTy::U128 => "u128",
1953 pub fn name(&self) -> Symbol {
1955 UintTy::Usize => sym::usize,
1956 UintTy::U8 => sym::u8,
1957 UintTy::U16 => sym::u16,
1958 UintTy::U32 => sym::u32,
1959 UintTy::U64 => sym::u64,
1960 UintTy::U128 => sym::u128,
1965 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1966 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1967 #[derive(Clone, Encodable, Decodable, Debug)]
1968 pub struct AssocConstraint {
1971 pub gen_args: Option<GenericArgs>,
1972 pub kind: AssocConstraintKind,
1976 /// The kinds of an `AssocConstraint`.
1977 #[derive(Clone, Encodable, Decodable, Debug)]
1983 impl From<P<Ty>> for Term {
1984 fn from(v: P<Ty>) -> Self {
1989 impl From<AnonConst> for Term {
1990 fn from(v: AnonConst) -> Self {
1995 /// The kinds of an `AssocConstraint`.
1996 #[derive(Clone, Encodable, Decodable, Debug)]
1997 pub enum AssocConstraintKind {
1998 /// E.g., `A = Bar`, `A = 3` in `Foo<A = Bar>` where A is an associated type.
1999 Equality { term: Term },
2000 /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
2001 Bound { bounds: GenericBounds },
2004 #[derive(Encodable, Decodable, Debug)]
2009 pub tokens: Option<LazyAttrTokenStream>,
2013 fn clone(&self) -> Self {
2014 ensure_sufficient_stack(|| Self {
2016 kind: self.kind.clone(),
2018 tokens: self.tokens.clone(),
2024 pub fn peel_refs(&self) -> &Self {
2025 let mut final_ty = self;
2026 while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
2033 #[derive(Clone, Encodable, Decodable, Debug)]
2034 pub struct BareFnTy {
2035 pub unsafety: Unsafe,
2037 pub generic_params: Vec<GenericParam>,
2038 pub decl: P<FnDecl>,
2039 /// Span of the `fn(...) -> ...` part.
2040 pub decl_span: Span,
2043 /// The various kinds of type recognized by the compiler.
2044 #[derive(Clone, Encodable, Decodable, Debug)]
2046 /// A variable-length slice (`[T]`).
2048 /// A fixed length array (`[T; n]`).
2049 Array(P<Ty>, AnonConst),
2050 /// A raw pointer (`*const T` or `*mut T`).
2052 /// A reference (`&'a T` or `&'a mut T`).
2053 Rptr(Option<Lifetime>, MutTy),
2054 /// A bare function (e.g., `fn(usize) -> bool`).
2055 BareFn(P<BareFnTy>),
2056 /// The never type (`!`).
2058 /// A tuple (`(A, B, C, D,...)`).
2060 /// A path (`module::module::...::Type`), optionally
2061 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
2063 /// Type parameters are stored in the `Path` itself.
2064 Path(Option<P<QSelf>>, Path),
2065 /// A trait object type `Bound1 + Bound2 + Bound3`
2066 /// where `Bound` is a trait or a lifetime.
2067 TraitObject(GenericBounds, TraitObjectSyntax),
2068 /// An `impl Bound1 + Bound2 + Bound3` type
2069 /// where `Bound` is a trait or a lifetime.
2071 /// The `NodeId` exists to prevent lowering from having to
2072 /// generate `NodeId`s on the fly, which would complicate
2073 /// the generation of opaque `type Foo = impl Trait` items significantly.
2074 ImplTrait(NodeId, GenericBounds),
2075 /// No-op; kept solely so that we can pretty-print faithfully.
2079 /// This means the type should be inferred instead of it having been
2080 /// specified. This can appear anywhere in a type.
2082 /// Inferred type of a `self` or `&self` argument in a method.
2084 /// A macro in the type position.
2085 MacCall(P<MacCall>),
2086 /// Placeholder for a kind that has failed to be defined.
2088 /// Placeholder for a `va_list`.
2093 pub fn is_implicit_self(&self) -> bool {
2094 matches!(self, TyKind::ImplicitSelf)
2097 pub fn is_unit(&self) -> bool {
2098 matches!(self, TyKind::Tup(tys) if tys.is_empty())
2101 pub fn is_simple_path(&self) -> Option<Symbol> {
2102 if let TyKind::Path(None, Path { segments, .. }) = &self
2103 && let [segment] = &segments[..]
2104 && segment.args.is_none()
2106 Some(segment.ident.name)
2113 /// Syntax used to declare a trait object.
2114 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2115 pub enum TraitObjectSyntax {
2121 /// Inline assembly operand explicit register or register class.
2123 /// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
2124 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2125 pub enum InlineAsmRegOrRegClass {
2130 bitflags::bitflags! {
2131 #[derive(Encodable, Decodable, HashStable_Generic)]
2132 pub struct InlineAsmOptions: u16 {
2133 const PURE = 1 << 0;
2134 const NOMEM = 1 << 1;
2135 const READONLY = 1 << 2;
2136 const PRESERVES_FLAGS = 1 << 3;
2137 const NORETURN = 1 << 4;
2138 const NOSTACK = 1 << 5;
2139 const ATT_SYNTAX = 1 << 6;
2141 const MAY_UNWIND = 1 << 8;
2145 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
2146 pub enum InlineAsmTemplatePiece {
2148 Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
2151 impl fmt::Display for InlineAsmTemplatePiece {
2152 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2154 Self::String(s) => {
2155 for c in s.chars() {
2157 '{' => f.write_str("{{")?,
2158 '}' => f.write_str("}}")?,
2164 Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
2165 write!(f, "{{{}:{}}}", operand_idx, modifier)
2167 Self::Placeholder { operand_idx, modifier: None, .. } => {
2168 write!(f, "{{{}}}", operand_idx)
2174 impl InlineAsmTemplatePiece {
2175 /// Rebuilds the asm template string from its pieces.
2176 pub fn to_string(s: &[Self]) -> String {
2178 let mut out = String::new();
2180 let _ = write!(out, "{}", p);
2186 /// Inline assembly symbol operands get their own AST node that is somewhat
2187 /// similar to `AnonConst`.
2189 /// The main difference is that we specifically don't assign it `DefId` in
2190 /// `DefCollector`. Instead this is deferred until AST lowering where we
2191 /// lower it to an `AnonConst` (for functions) or a `Path` (for statics)
2192 /// depending on what the path resolves to.
2193 #[derive(Clone, Encodable, Decodable, Debug)]
2194 pub struct InlineAsmSym {
2196 pub qself: Option<P<QSelf>>,
2200 /// Inline assembly operand.
2202 /// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
2203 #[derive(Clone, Encodable, Decodable, Debug)]
2204 pub enum InlineAsmOperand {
2206 reg: InlineAsmRegOrRegClass,
2210 reg: InlineAsmRegOrRegClass,
2212 expr: Option<P<Expr>>,
2215 reg: InlineAsmRegOrRegClass,
2220 reg: InlineAsmRegOrRegClass,
2223 out_expr: Option<P<Expr>>,
2226 anon_const: AnonConst,
2233 /// Inline assembly.
2235 /// E.g., `asm!("NOP");`.
2236 #[derive(Clone, Encodable, Decodable, Debug)]
2237 pub struct InlineAsm {
2238 pub template: Vec<InlineAsmTemplatePiece>,
2239 pub template_strs: Box<[(Symbol, Option<Symbol>, Span)]>,
2240 pub operands: Vec<(InlineAsmOperand, Span)>,
2241 pub clobber_abis: Vec<(Symbol, Span)>,
2242 pub options: InlineAsmOptions,
2243 pub line_spans: Vec<Span>,
2246 /// A parameter in a function header.
2248 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
2249 #[derive(Clone, Encodable, Decodable, Debug)]
2256 pub is_placeholder: bool,
2259 /// Alternative representation for `Arg`s describing `self` parameter of methods.
2261 /// E.g., `&mut self` as in `fn foo(&mut self)`.
2262 #[derive(Clone, Encodable, Decodable, Debug)]
2264 /// `self`, `mut self`
2266 /// `&'lt self`, `&'lt mut self`
2267 Region(Option<Lifetime>, Mutability),
2268 /// `self: TYPE`, `mut self: TYPE`
2269 Explicit(P<Ty>, Mutability),
2272 pub type ExplicitSelf = Spanned<SelfKind>;
2275 /// Attempts to cast parameter to `ExplicitSelf`.
2276 pub fn to_self(&self) -> Option<ExplicitSelf> {
2277 if let PatKind::Ident(BindingAnnotation(ByRef::No, mutbl), ident, _) = self.pat.kind {
2278 if ident.name == kw::SelfLower {
2279 return match self.ty.kind {
2280 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
2281 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
2282 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
2285 self.pat.span.to(self.ty.span),
2286 SelfKind::Explicit(self.ty.clone(), mutbl),
2294 /// Returns `true` if parameter is `self`.
2295 pub fn is_self(&self) -> bool {
2296 if let PatKind::Ident(_, ident, _) = self.pat.kind {
2297 ident.name == kw::SelfLower
2303 /// Builds a `Param` object from `ExplicitSelf`.
2304 pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
2305 let span = eself.span.to(eself_ident.span);
2306 let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
2307 let (mutbl, ty) = match eself.node {
2308 SelfKind::Explicit(ty, mutbl) => (mutbl, ty),
2309 SelfKind::Value(mutbl) => (mutbl, infer_ty),
2310 SelfKind::Region(lt, mutbl) => (
2314 kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
2324 kind: PatKind::Ident(BindingAnnotation(ByRef::No, mutbl), eself_ident, None),
2331 is_placeholder: false,
2336 /// A signature (not the body) of a function declaration.
2338 /// E.g., `fn foo(bar: baz)`.
2340 /// Please note that it's different from `FnHeader` structure
2341 /// which contains metadata about function safety, asyncness, constness and ABI.
2342 #[derive(Clone, Encodable, Decodable, Debug)]
2344 pub inputs: Vec<Param>,
2345 pub output: FnRetTy,
2349 pub fn has_self(&self) -> bool {
2350 self.inputs.get(0).map_or(false, Param::is_self)
2352 pub fn c_variadic(&self) -> bool {
2353 self.inputs.last().map_or(false, |arg| matches!(arg.ty.kind, TyKind::CVarArgs))
2357 /// Is the trait definition an auto trait?
2358 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2364 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2365 #[derive(HashStable_Generic)]
2371 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2373 Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
2378 pub fn is_async(self) -> bool {
2379 matches!(self, Async::Yes { .. })
2382 /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
2383 pub fn opt_return_id(self) -> Option<(NodeId, Span)> {
2385 Async::Yes { return_impl_trait_id, span, .. } => Some((return_impl_trait_id, span)),
2391 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2392 #[derive(HashStable_Generic)]
2398 /// Item defaultness.
2399 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
2400 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2401 pub enum Defaultness {
2406 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
2407 pub enum ImplPolarity {
2408 /// `impl Trait for Type`
2410 /// `impl !Trait for Type`
2414 impl fmt::Debug for ImplPolarity {
2415 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2417 ImplPolarity::Positive => "positive".fmt(f),
2418 ImplPolarity::Negative(_) => "negative".fmt(f),
2423 #[derive(Clone, Encodable, Decodable, Debug)]
2425 /// Returns type is not specified.
2427 /// Functions default to `()` and closures default to inference.
2428 /// Span points to where return type would be inserted.
2430 /// Everything else.
2435 pub fn span(&self) -> Span {
2437 &FnRetTy::Default(span) => span,
2438 FnRetTy::Ty(ty) => ty.span,
2443 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
2449 /// Module item kind.
2450 #[derive(Clone, Encodable, Decodable, Debug)]
2452 /// Module with inlined definition `mod foo { ... }`,
2453 /// or with definition outlined to a separate file `mod foo;` and already loaded from it.
2454 /// The inner span is from the first token past `{` to the last token until `}`,
2455 /// or from the first to the last token in the loaded file.
2456 Loaded(Vec<P<Item>>, Inline, ModSpans),
2457 /// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
2461 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2462 pub struct ModSpans {
2463 /// `inner_span` covers the body of the module; for a file module, its the whole file.
2464 /// For an inline module, its the span inside the `{ ... }`, not including the curly braces.
2465 pub inner_span: Span,
2466 pub inject_use_span: Span,
2469 impl Default for ModSpans {
2470 fn default() -> ModSpans {
2471 ModSpans { inner_span: Default::default(), inject_use_span: Default::default() }
2475 /// Foreign module declaration.
2477 /// E.g., `extern { .. }` or `extern "C" { .. }`.
2478 #[derive(Clone, Encodable, Decodable, Debug)]
2479 pub struct ForeignMod {
2480 /// `unsafe` keyword accepted syntactically for macro DSLs, but not
2481 /// semantically by Rust.
2482 pub unsafety: Unsafe,
2483 pub abi: Option<StrLit>,
2484 pub items: Vec<P<ForeignItem>>,
2487 #[derive(Clone, Encodable, Decodable, Debug)]
2488 pub struct EnumDef {
2489 pub variants: Vec<Variant>,
2492 #[derive(Clone, Encodable, Decodable, Debug)]
2493 pub struct Variant {
2494 /// Attributes of the variant.
2496 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2500 /// The visibility of the variant. Syntactically accepted but not semantically.
2501 pub vis: Visibility,
2502 /// Name of the variant.
2505 /// Fields and constructor id of the variant.
2506 pub data: VariantData,
2507 /// Explicit discriminant, e.g., `Foo = 1`.
2508 pub disr_expr: Option<AnonConst>,
2509 /// Is a macro placeholder
2510 pub is_placeholder: bool,
2513 /// Part of `use` item to the right of its prefix.
2514 #[derive(Clone, Encodable, Decodable, Debug)]
2515 pub enum UseTreeKind {
2516 /// `use prefix` or `use prefix as rename`
2518 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2520 Simple(Option<Ident>, NodeId, NodeId),
2521 /// `use prefix::{...}`
2522 Nested(Vec<(UseTree, NodeId)>),
2527 /// A tree of paths sharing common prefixes.
2528 /// Used in `use` items both at top-level and inside of braces in import groups.
2529 #[derive(Clone, Encodable, Decodable, Debug)]
2530 pub struct UseTree {
2532 pub kind: UseTreeKind,
2537 pub fn ident(&self) -> Ident {
2539 UseTreeKind::Simple(Some(rename), ..) => rename,
2540 UseTreeKind::Simple(None, ..) => {
2541 self.prefix.segments.last().expect("empty prefix in a simple import").ident
2543 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2548 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2549 /// are contained as statements within items. These two cases need to be
2550 /// distinguished for pretty-printing.
2551 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
2552 pub enum AttrStyle {
2557 rustc_index::newtype_index! {
2560 DEBUG_FORMAT = "AttrId({})"
2564 impl<S: Encoder> Encodable<S> for AttrId {
2565 fn encode(&self, _s: &mut S) {}
2568 impl<D: Decoder> Decodable<D> for AttrId {
2569 default fn decode(_: &mut D) -> AttrId {
2570 panic!("cannot decode `AttrId` with `{}`", std::any::type_name::<D>());
2574 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2575 pub struct AttrItem {
2578 pub tokens: Option<LazyAttrTokenStream>,
2581 /// A list of attributes.
2582 pub type AttrVec = ThinVec<Attribute>;
2584 /// Metadata associated with an item.
2585 #[derive(Clone, Encodable, Decodable, Debug)]
2586 pub struct Attribute {
2589 /// Denotes if the attribute decorates the following construct (outer)
2590 /// or the construct this attribute is contained within (inner).
2591 pub style: AttrStyle,
2595 #[derive(Clone, Encodable, Decodable, Debug)]
2596 pub struct NormalAttr {
2598 pub tokens: Option<LazyAttrTokenStream>,
2601 #[derive(Clone, Encodable, Decodable, Debug)]
2603 /// A normal attribute.
2604 Normal(P<NormalAttr>),
2606 /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
2607 /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
2608 /// variant (which is much less compact and thus more expensive).
2609 DocComment(CommentKind, Symbol),
2612 /// `TraitRef`s appear in impls.
2614 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2615 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2616 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2617 /// same as the impl's `NodeId`).
2618 #[derive(Clone, Encodable, Decodable, Debug)]
2619 pub struct TraitRef {
2624 #[derive(Clone, Encodable, Decodable, Debug)]
2625 pub struct PolyTraitRef {
2626 /// The `'a` in `for<'a> Foo<&'a T>`.
2627 pub bound_generic_params: Vec<GenericParam>,
2629 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2630 pub trait_ref: TraitRef,
2636 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2638 bound_generic_params: generic_params,
2639 trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
2645 #[derive(Clone, Encodable, Decodable, Debug)]
2646 pub struct Visibility {
2647 pub kind: VisibilityKind,
2649 pub tokens: Option<LazyAttrTokenStream>,
2652 #[derive(Clone, Encodable, Decodable, Debug)]
2653 pub enum VisibilityKind {
2655 Restricted { path: P<Path>, id: NodeId, shorthand: bool },
2659 impl VisibilityKind {
2660 pub fn is_pub(&self) -> bool {
2661 matches!(self, VisibilityKind::Public)
2665 /// Field definition in a struct, variant or union.
2667 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2668 #[derive(Clone, Encodable, Decodable, Debug)]
2669 pub struct FieldDef {
2673 pub vis: Visibility,
2674 pub ident: Option<Ident>,
2677 pub is_placeholder: bool,
2680 /// Fields and constructor ids of enum variants and structs.
2681 #[derive(Clone, Encodable, Decodable, Debug)]
2682 pub enum VariantData {
2685 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2686 Struct(Vec<FieldDef>, bool),
2689 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2690 Tuple(Vec<FieldDef>, NodeId),
2693 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2698 /// Return the fields of this variant.
2699 pub fn fields(&self) -> &[FieldDef] {
2701 VariantData::Struct(fields, ..) | VariantData::Tuple(fields, _) => fields,
2706 /// Return the `NodeId` of this variant's constructor, if it has one.
2707 pub fn ctor_node_id(&self) -> Option<NodeId> {
2709 VariantData::Struct(..) => None,
2710 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2715 /// An item definition.
2716 #[derive(Clone, Encodable, Decodable, Debug)]
2717 pub struct Item<K = ItemKind> {
2721 pub vis: Visibility,
2722 /// The name of the item.
2723 /// It might be a dummy name in case of anonymous items.
2728 /// Original tokens this item was parsed from. This isn't necessarily
2729 /// available for all items, although over time more and more items should
2730 /// have this be `Some`. Right now this is primarily used for procedural
2731 /// macros, notably custom attributes.
2733 /// Note that the tokens here do not include the outer attributes, but will
2734 /// include inner attributes.
2735 pub tokens: Option<LazyAttrTokenStream>,
2739 /// Return the span that encompasses the attributes.
2740 pub fn span_with_attributes(&self) -> Span {
2741 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2745 /// `extern` qualifier on a function item or function type.
2746 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2750 Explicit(StrLit, Span),
2754 pub fn from_abi(abi: Option<StrLit>, span: Span) -> Extern {
2756 Some(name) => Extern::Explicit(name, span),
2757 None => Extern::Implicit(span),
2762 /// A function header.
2764 /// All the information between the visibility and the name of the function is
2765 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2766 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2767 pub struct FnHeader {
2768 pub unsafety: Unsafe,
2769 pub asyncness: Async,
2770 pub constness: Const,
2775 /// Does this function header have any qualifiers or is it empty?
2776 pub fn has_qualifiers(&self) -> bool {
2777 let Self { unsafety, asyncness, constness, ext } = self;
2778 matches!(unsafety, Unsafe::Yes(_))
2779 || asyncness.is_async()
2780 || matches!(constness, Const::Yes(_))
2781 || !matches!(ext, Extern::None)
2785 impl Default for FnHeader {
2786 fn default() -> FnHeader {
2788 unsafety: Unsafe::No,
2789 asyncness: Async::No,
2790 constness: Const::No,
2796 #[derive(Clone, Encodable, Decodable, Debug)]
2798 pub unsafety: Unsafe,
2799 pub is_auto: IsAuto,
2800 pub generics: Generics,
2801 pub bounds: GenericBounds,
2802 pub items: Vec<P<AssocItem>>,
2805 /// The location of a where clause on a `TyAlias` (`Span`) and whether there was
2806 /// a `where` keyword (`bool`). This is split out from `WhereClause`, since there
2807 /// are two locations for where clause on type aliases, but their predicates
2808 /// are concatenated together.
2810 /// Take this example:
2811 /// ```ignore (only-for-syntax-highlight)
2813 /// type Assoc<'a, 'b> where Self: 'a, Self: 'b;
2815 /// impl Foo for () {
2816 /// type Assoc<'a, 'b> where Self: 'a = () where Self: 'b;
2817 /// // ^^^^^^^^^^^^^^ first where clause
2818 /// // ^^^^^^^^^^^^^^ second where clause
2822 /// If there is no where clause, then this is `false` with `DUMMY_SP`.
2823 #[derive(Copy, Clone, Encodable, Decodable, Debug, Default)]
2824 pub struct TyAliasWhereClause(pub bool, pub Span);
2826 #[derive(Clone, Encodable, Decodable, Debug)]
2827 pub struct TyAlias {
2828 pub defaultness: Defaultness,
2829 pub generics: Generics,
2830 /// The span information for the two where clauses (before equals, after equals)
2831 pub where_clauses: (TyAliasWhereClause, TyAliasWhereClause),
2832 /// The index in `generics.where_clause.predicates` that would split into
2833 /// predicates from the where clause before the equals and the predicates
2834 /// from the where clause after the equals
2835 pub where_predicates_split: usize,
2836 pub bounds: GenericBounds,
2837 pub ty: Option<P<Ty>>,
2840 #[derive(Clone, Encodable, Decodable, Debug)]
2842 pub defaultness: Defaultness,
2843 pub unsafety: Unsafe,
2844 pub generics: Generics,
2845 pub constness: Const,
2846 pub polarity: ImplPolarity,
2847 /// The trait being implemented, if any.
2848 pub of_trait: Option<TraitRef>,
2850 pub items: Vec<P<AssocItem>>,
2853 #[derive(Clone, Encodable, Decodable, Debug)]
2855 pub defaultness: Defaultness,
2856 pub generics: Generics,
2858 pub body: Option<P<Block>>,
2861 #[derive(Clone, Encodable, Decodable, Debug)]
2863 /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
2865 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2866 ExternCrate(Option<Symbol>),
2867 /// A use declaration item (`use`).
2869 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2871 /// A static item (`static`).
2873 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2874 Static(P<Ty>, Mutability, Option<P<Expr>>),
2875 /// A constant item (`const`).
2877 /// E.g., `const FOO: i32 = 42;`.
2878 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2879 /// A function declaration (`fn`).
2881 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2883 /// A module declaration (`mod`).
2885 /// E.g., `mod foo;` or `mod foo { .. }`.
2886 /// `unsafe` keyword on modules is accepted syntactically for macro DSLs, but not
2887 /// semantically by Rust.
2888 Mod(Unsafe, ModKind),
2889 /// An external module (`extern`).
2891 /// E.g., `extern {}` or `extern "C" {}`.
2892 ForeignMod(ForeignMod),
2893 /// Module-level inline assembly (from `global_asm!()`).
2894 GlobalAsm(Box<InlineAsm>),
2895 /// A type alias (`type`).
2897 /// E.g., `type Foo = Bar<u8>;`.
2898 TyAlias(Box<TyAlias>),
2899 /// An enum definition (`enum`).
2901 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2902 Enum(EnumDef, Generics),
2903 /// A struct definition (`struct`).
2905 /// E.g., `struct Foo<A> { x: A }`.
2906 Struct(VariantData, Generics),
2907 /// A union definition (`union`).
2909 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2910 Union(VariantData, Generics),
2911 /// A trait declaration (`trait`).
2913 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2917 /// E.g., `trait Foo = Bar + Quux;`.
2918 TraitAlias(Generics, GenericBounds),
2919 /// An implementation.
2921 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2923 /// A macro invocation.
2925 /// E.g., `foo!(..)`.
2926 MacCall(P<MacCall>),
2928 /// A macro definition.
2933 pub fn article(&self) -> &str {
2936 Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
2937 | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
2938 ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
2942 pub fn descr(&self) -> &str {
2944 ItemKind::ExternCrate(..) => "extern crate",
2945 ItemKind::Use(..) => "`use` import",
2946 ItemKind::Static(..) => "static item",
2947 ItemKind::Const(..) => "constant item",
2948 ItemKind::Fn(..) => "function",
2949 ItemKind::Mod(..) => "module",
2950 ItemKind::ForeignMod(..) => "extern block",
2951 ItemKind::GlobalAsm(..) => "global asm item",
2952 ItemKind::TyAlias(..) => "type alias",
2953 ItemKind::Enum(..) => "enum",
2954 ItemKind::Struct(..) => "struct",
2955 ItemKind::Union(..) => "union",
2956 ItemKind::Trait(..) => "trait",
2957 ItemKind::TraitAlias(..) => "trait alias",
2958 ItemKind::MacCall(..) => "item macro invocation",
2959 ItemKind::MacroDef(..) => "macro definition",
2960 ItemKind::Impl { .. } => "implementation",
2964 pub fn generics(&self) -> Option<&Generics> {
2966 Self::Fn(box Fn { generics, .. })
2967 | Self::TyAlias(box TyAlias { generics, .. })
2968 | Self::Enum(_, generics)
2969 | Self::Struct(_, generics)
2970 | Self::Union(_, generics)
2971 | Self::Trait(box Trait { generics, .. })
2972 | Self::TraitAlias(generics, _)
2973 | Self::Impl(box Impl { generics, .. }) => Some(generics),
2979 /// Represents associated items.
2980 /// These include items in `impl` and `trait` definitions.
2981 pub type AssocItem = Item<AssocItemKind>;
2983 /// Represents associated item kinds.
2985 /// The term "provided" in the variants below refers to the item having a default
2986 /// definition / body. Meanwhile, a "required" item lacks a definition / body.
2987 /// In an implementation, all items must be provided.
2988 /// The `Option`s below denote the bodies, where `Some(_)`
2989 /// means "provided" and conversely `None` means "required".
2990 #[derive(Clone, Encodable, Decodable, Debug)]
2991 pub enum AssocItemKind {
2992 /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
2993 /// If `def` is parsed, then the constant is provided, and otherwise required.
2994 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2995 /// An associated function.
2997 /// An associated type.
2999 /// A macro expanding to associated items.
3000 MacCall(P<MacCall>),
3003 impl AssocItemKind {
3004 pub fn defaultness(&self) -> Defaultness {
3006 Self::Const(defaultness, ..)
3007 | Self::Fn(box Fn { defaultness, .. })
3008 | Self::Type(box TyAlias { defaultness, .. }) => defaultness,
3009 Self::MacCall(..) => Defaultness::Final,
3014 impl From<AssocItemKind> for ItemKind {
3015 fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
3016 match assoc_item_kind {
3017 AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
3018 AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
3019 AssocItemKind::Type(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
3020 AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
3025 impl TryFrom<ItemKind> for AssocItemKind {
3026 type Error = ItemKind;
3028 fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
3029 Ok(match item_kind {
3030 ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
3031 ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
3032 ItemKind::TyAlias(ty_kind) => AssocItemKind::Type(ty_kind),
3033 ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
3034 _ => return Err(item_kind),
3039 /// An item in `extern` block.
3040 #[derive(Clone, Encodable, Decodable, Debug)]
3041 pub enum ForeignItemKind {
3042 /// A foreign static item (`static FOO: u8`).
3043 Static(P<Ty>, Mutability, Option<P<Expr>>),
3044 /// An foreign function.
3046 /// An foreign type.
3047 TyAlias(Box<TyAlias>),
3048 /// A macro expanding to foreign items.
3049 MacCall(P<MacCall>),
3052 impl From<ForeignItemKind> for ItemKind {
3053 fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
3054 match foreign_item_kind {
3055 ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
3056 ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
3057 ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
3058 ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
3063 impl TryFrom<ItemKind> for ForeignItemKind {
3064 type Error = ItemKind;
3066 fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
3067 Ok(match item_kind {
3068 ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
3069 ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
3070 ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
3071 ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
3072 _ => return Err(item_kind),
3077 pub type ForeignItem = Item<ForeignItemKind>;
3079 // Some nodes are used a lot. Make sure they don't unintentionally get bigger.
3080 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
3083 use rustc_data_structures::static_assert_size;
3084 // tidy-alphabetical-start
3085 static_assert_size!(AssocItem, 104);
3086 static_assert_size!(AssocItemKind, 32);
3087 static_assert_size!(Attribute, 32);
3088 static_assert_size!(Block, 48);
3089 static_assert_size!(Expr, 72);
3090 static_assert_size!(ExprKind, 40);
3091 static_assert_size!(Fn, 184);
3092 static_assert_size!(ForeignItem, 96);
3093 static_assert_size!(ForeignItemKind, 24);
3094 static_assert_size!(GenericArg, 24);
3095 static_assert_size!(GenericBound, 72);
3096 static_assert_size!(Generics, 72);
3097 static_assert_size!(Impl, 184);
3098 static_assert_size!(Item, 184);
3099 static_assert_size!(ItemKind, 112);
3100 static_assert_size!(LitKind, 24);
3101 static_assert_size!(Local, 72);
3102 static_assert_size!(MetaItemLit, 48);
3103 static_assert_size!(Param, 40);
3104 static_assert_size!(Pat, 88);
3105 static_assert_size!(Path, 24);
3106 static_assert_size!(PathSegment, 24);
3107 static_assert_size!(PatKind, 64);
3108 static_assert_size!(Stmt, 32);
3109 static_assert_size!(StmtKind, 16);
3110 static_assert_size!(Ty, 64);
3111 static_assert_size!(TyKind, 40);
3112 // tidy-alphabetical-end