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 //! - [`Lit`] 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, LazyTokenStream, TokenStream};
29 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
30 use rustc_data_structures::stack::ensure_sufficient_stack;
31 use rustc_data_structures::sync::Lrc;
32 use rustc_data_structures::thin_vec::ThinVec;
33 use rustc_macros::HashStable_Generic;
34 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
35 use rustc_span::source_map::{respan, Spanned};
36 use rustc_span::symbol::{kw, sym, Ident, Symbol};
37 use rustc_span::{Span, DUMMY_SP};
39 use std::cmp::Ordering;
40 use std::convert::TryFrom;
44 /// A "Label" is an identifier of some point in sources,
45 /// e.g. in the following code:
53 /// `'outer` is a label.
54 #[derive(Clone, Encodable, Decodable, Copy, HashStable_Generic, Eq, PartialEq)]
59 impl fmt::Debug for Label {
60 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
61 write!(f, "label({:?})", self.ident)
65 /// A "Lifetime" is an annotation of the scope in which variable
66 /// can be used, e.g. `'a` in `&'a i32`.
67 #[derive(Clone, Encodable, Decodable, Copy, PartialEq, Eq)]
73 impl fmt::Debug for Lifetime {
74 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
75 write!(f, "lifetime({}: {})", self.id, self)
79 impl fmt::Display for Lifetime {
80 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
81 write!(f, "{}", self.ident.name)
85 /// A "Path" is essentially Rust's notion of a name.
87 /// It's represented as a sequence of identifiers,
88 /// along with a bunch of supporting information.
90 /// E.g., `std::cmp::PartialEq`.
91 #[derive(Clone, Encodable, Decodable, Debug)]
94 /// The segments in the path: the things separated by `::`.
95 /// Global paths begin with `kw::PathRoot`.
96 pub segments: Vec<PathSegment>,
97 pub tokens: Option<LazyTokenStream>,
100 impl PartialEq<Symbol> for Path {
102 fn eq(&self, symbol: &Symbol) -> bool {
103 self.segments.len() == 1 && { self.segments[0].ident.name == *symbol }
107 impl<CTX: rustc_span::HashStableContext> HashStable<CTX> for Path {
108 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
109 self.segments.len().hash_stable(hcx, hasher);
110 for segment in &self.segments {
111 segment.ident.hash_stable(hcx, hasher);
117 // Convert a span and an identifier to the corresponding
119 pub fn from_ident(ident: Ident) -> Path {
120 Path { segments: vec![PathSegment::from_ident(ident)], span: ident.span, tokens: None }
123 pub fn is_global(&self) -> bool {
124 !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
128 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
130 /// E.g., `std`, `String` or `Box<T>`.
131 #[derive(Clone, Encodable, Decodable, Debug)]
132 pub struct PathSegment {
133 /// The identifier portion of this path segment.
138 /// Type/lifetime parameters attached to this path. They come in
139 /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
140 /// `None` means that no parameter list is supplied (`Path`),
141 /// `Some` means that parameter list is supplied (`Path<X, Y>`)
142 /// but it can be empty (`Path<>`).
143 /// `P` is used as a size optimization for the common case with no parameters.
144 pub args: Option<P<GenericArgs>>,
148 pub fn from_ident(ident: Ident) -> Self {
149 PathSegment { ident, id: DUMMY_NODE_ID, args: None }
152 pub fn path_root(span: Span) -> Self {
153 PathSegment::from_ident(Ident::new(kw::PathRoot, span))
156 pub fn span(&self) -> Span {
158 Some(args) => self.ident.span.to(args.span()),
159 None => self.ident.span,
164 /// The arguments of a path segment.
166 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
167 #[derive(Clone, Encodable, Decodable, Debug)]
168 pub enum GenericArgs {
169 /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
170 AngleBracketed(AngleBracketedArgs),
171 /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
172 Parenthesized(ParenthesizedArgs),
176 pub fn is_angle_bracketed(&self) -> bool {
177 matches!(self, AngleBracketed(..))
180 pub fn span(&self) -> Span {
182 AngleBracketed(ref data) => data.span,
183 Parenthesized(ref data) => data.span,
188 /// Concrete argument in the sequence of generic args.
189 #[derive(Clone, Encodable, Decodable, Debug)]
190 pub enum GenericArg {
191 /// `'a` in `Foo<'a>`
193 /// `Bar` in `Foo<Bar>`
200 pub fn span(&self) -> Span {
202 GenericArg::Lifetime(lt) => lt.ident.span,
203 GenericArg::Type(ty) => ty.span,
204 GenericArg::Const(ct) => ct.value.span,
209 /// A path like `Foo<'a, T>`.
210 #[derive(Clone, Encodable, Decodable, Debug, Default)]
211 pub struct AngleBracketedArgs {
212 /// The overall span.
214 /// The comma separated parts in the `<...>`.
215 pub args: Vec<AngleBracketedArg>,
218 /// Either an argument for a parameter e.g., `'a`, `Vec<u8>`, `0`,
219 /// or a constraint on an associated item, e.g., `Item = String` or `Item: Bound`.
220 #[derive(Clone, Encodable, Decodable, Debug)]
221 pub enum AngleBracketedArg {
222 /// Argument for a generic parameter.
224 /// Constraint for an associated item.
225 Constraint(AssocConstraint),
228 impl AngleBracketedArg {
229 pub fn span(&self) -> Span {
231 AngleBracketedArg::Arg(arg) => arg.span(),
232 AngleBracketedArg::Constraint(constraint) => constraint.span,
237 impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
238 fn into(self) -> Option<P<GenericArgs>> {
239 Some(P(GenericArgs::AngleBracketed(self)))
243 impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
244 fn into(self) -> Option<P<GenericArgs>> {
245 Some(P(GenericArgs::Parenthesized(self)))
249 /// A path like `Foo(A, B) -> C`.
250 #[derive(Clone, Encodable, Decodable, Debug)]
251 pub struct ParenthesizedArgs {
259 pub inputs: Vec<P<Ty>>,
265 pub inputs_span: Span,
271 impl ParenthesizedArgs {
272 pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
277 .map(|input| AngleBracketedArg::Arg(GenericArg::Type(input)))
279 AngleBracketedArgs { span: self.inputs_span, args }
283 pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
285 /// A modifier on a bound, e.g., `?Trait` or `~const Trait`.
287 /// Negative bounds should also be handled here.
288 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
289 pub enum TraitBoundModifier {
301 // This parses but will be rejected during AST validation.
305 /// The AST represents all type param bounds as types.
306 /// `typeck::collect::compute_bounds` matches these against
307 /// the "special" built-in traits (see `middle::lang_items`) and
308 /// detects `Copy`, `Send` and `Sync`.
309 #[derive(Clone, Encodable, Decodable, Debug)]
310 pub enum GenericBound {
311 Trait(PolyTraitRef, TraitBoundModifier),
316 pub fn span(&self) -> Span {
318 GenericBound::Trait(ref t, ..) => t.span,
319 GenericBound::Outlives(ref l) => l.ident.span,
324 pub type GenericBounds = Vec<GenericBound>;
326 /// Specifies the enforced ordering for generic parameters. In the future,
327 /// if we wanted to relax this order, we could override `PartialEq` and
328 /// `PartialOrd`, to allow the kinds to be unordered.
329 #[derive(Hash, Clone, Copy)]
330 pub enum ParamKindOrd {
334 // `Infer` is not actually constructed directly from the AST, but is implicitly constructed
335 // during HIR lowering, and `ParamKindOrd` will implicitly order inferred variables last.
339 impl Ord for ParamKindOrd {
340 fn cmp(&self, other: &Self) -> Ordering {
342 let to_int = |v| match v {
344 Infer | Type | Const => 1,
347 to_int(*self).cmp(&to_int(*other))
350 impl PartialOrd for ParamKindOrd {
351 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
352 Some(self.cmp(other))
355 impl PartialEq for ParamKindOrd {
356 fn eq(&self, other: &Self) -> bool {
357 self.cmp(other) == Ordering::Equal
360 impl Eq for ParamKindOrd {}
362 impl fmt::Display for ParamKindOrd {
363 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
365 ParamKindOrd::Lifetime => "lifetime".fmt(f),
366 ParamKindOrd::Type => "type".fmt(f),
367 ParamKindOrd::Const { .. } => "const".fmt(f),
368 ParamKindOrd::Infer => "infer".fmt(f),
373 #[derive(Clone, Encodable, Decodable, Debug)]
374 pub enum GenericParamKind {
375 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
378 default: Option<P<Ty>>,
382 /// Span of the `const` keyword.
384 /// Optional default value for the const generic param
385 default: Option<AnonConst>,
389 #[derive(Clone, Encodable, Decodable, Debug)]
390 pub struct GenericParam {
394 pub bounds: GenericBounds,
395 pub is_placeholder: bool,
396 pub kind: GenericParamKind,
397 pub colon_span: Option<Span>,
401 pub fn span(&self) -> Span {
403 GenericParamKind::Lifetime | GenericParamKind::Type { default: None } => {
406 GenericParamKind::Type { default: Some(ty) } => self.ident.span.to(ty.span),
407 GenericParamKind::Const { kw_span, default: Some(default), .. } => {
408 kw_span.to(default.value.span)
410 GenericParamKind::Const { kw_span, default: None, ty } => kw_span.to(ty.span),
415 /// Represents lifetime, type and const parameters attached to a declaration of
416 /// a function, enum, trait, etc.
417 #[derive(Clone, Encodable, Decodable, Debug)]
418 pub struct Generics {
419 pub params: Vec<GenericParam>,
420 pub where_clause: WhereClause,
424 impl Default for Generics {
425 /// Creates an instance of `Generics`.
426 fn default() -> Generics {
429 where_clause: WhereClause {
430 has_where_token: false,
431 predicates: Vec::new(),
439 /// A where-clause in a definition.
440 #[derive(Clone, Encodable, Decodable, Debug)]
441 pub struct WhereClause {
442 /// `true` if we ate a `where` token: this can happen
443 /// if we parsed no predicates (e.g. `struct Foo where {}`).
444 /// This allows us to pretty-print accurately.
445 pub has_where_token: bool,
446 pub predicates: Vec<WherePredicate>,
450 /// A single predicate in a where-clause.
451 #[derive(Clone, Encodable, Decodable, Debug)]
452 pub enum WherePredicate {
453 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
454 BoundPredicate(WhereBoundPredicate),
455 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
456 RegionPredicate(WhereRegionPredicate),
457 /// An equality predicate (unsupported).
458 EqPredicate(WhereEqPredicate),
461 impl WherePredicate {
462 pub fn span(&self) -> Span {
464 WherePredicate::BoundPredicate(p) => p.span,
465 WherePredicate::RegionPredicate(p) => p.span,
466 WherePredicate::EqPredicate(p) => p.span,
473 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
474 #[derive(Clone, Encodable, Decodable, Debug)]
475 pub struct WhereBoundPredicate {
477 /// Any generics from a `for` binding.
478 pub bound_generic_params: Vec<GenericParam>,
479 /// The type being bounded.
480 pub bounded_ty: P<Ty>,
481 /// Trait and lifetime bounds (`Clone + Send + 'static`).
482 pub bounds: GenericBounds,
485 /// A lifetime predicate.
487 /// E.g., `'a: 'b + 'c`.
488 #[derive(Clone, Encodable, Decodable, Debug)]
489 pub struct WhereRegionPredicate {
491 pub lifetime: Lifetime,
492 pub bounds: GenericBounds,
495 /// An equality predicate (unsupported).
498 #[derive(Clone, Encodable, Decodable, Debug)]
499 pub struct WhereEqPredicate {
505 #[derive(Clone, Encodable, Decodable, Debug)]
508 pub items: Vec<P<Item>>,
510 /// Must be equal to `CRATE_NODE_ID` after the crate root is expanded, but may hold
511 /// expansion placeholders or an unassigned value (`DUMMY_NODE_ID`) before that.
513 pub is_placeholder: bool,
516 /// Possible values inside of compile-time attribute lists.
518 /// E.g., the '..' in `#[name(..)]`.
519 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
520 pub enum NestedMetaItem {
521 /// A full MetaItem, for recursive meta items.
525 /// E.g., `"foo"`, `64`, `true`.
529 /// A spanned compile-time attribute item.
531 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
532 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
533 pub struct MetaItem {
535 pub kind: MetaItemKind,
539 /// A compile-time attribute item.
541 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
542 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
543 pub enum MetaItemKind {
546 /// E.g., `test` as in `#[test]`.
550 /// E.g., `derive(..)` as in `#[derive(..)]`.
551 List(Vec<NestedMetaItem>),
552 /// Name value meta item.
554 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
558 /// A block (`{ .. }`).
560 /// E.g., `{ .. }` as in `fn foo() { .. }`.
561 #[derive(Clone, Encodable, Decodable, Debug)]
563 /// The statements in the block.
564 pub stmts: Vec<Stmt>,
566 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
567 pub rules: BlockCheckMode,
569 pub tokens: Option<LazyTokenStream>,
570 /// The following *isn't* a parse error, but will cause multiple errors in following stages.
577 pub could_be_bare_literal: bool,
582 /// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
583 #[derive(Clone, Encodable, Decodable, Debug)]
588 pub tokens: Option<LazyTokenStream>,
592 /// Attempt reparsing the pattern as a type.
593 /// This is intended for use by diagnostics.
594 pub fn to_ty(&self) -> Option<P<Ty>> {
595 let kind = match &self.kind {
596 // In a type expression `_` is an inference variable.
597 PatKind::Wild => TyKind::Infer,
598 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
599 PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
600 TyKind::Path(None, Path::from_ident(*ident))
602 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
603 PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
604 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
605 PatKind::Ref(pat, mutbl) => {
606 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
608 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
609 // when `P` can be reparsed as a type `T`.
610 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
611 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
612 // assuming `T0` to `Tn` are all syntactically valid as types.
613 PatKind::Tuple(pats) => {
614 let mut tys = Vec::with_capacity(pats.len());
615 // FIXME(#48994) - could just be collected into an Option<Vec>
617 tys.push(pat.to_ty()?);
624 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
627 /// Walk top-down and call `it` in each place where a pattern occurs
628 /// starting with the root pattern `walk` is called on. If `it` returns
629 /// false then we will descend no further but siblings will be processed.
630 pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
636 // Walk into the pattern associated with `Ident` (if any).
637 PatKind::Ident(_, _, Some(p)) => p.walk(it),
639 // Walk into each field of struct.
640 PatKind::Struct(_, _, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
642 // Sequence of patterns.
643 PatKind::TupleStruct(_, _, s)
646 | PatKind::Or(s) => s.iter().for_each(|p| p.walk(it)),
648 // Trivial wrappers over inner patterns.
649 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
651 // These patterns do not contain subpatterns, skip.
658 | PatKind::MacCall(_) => {}
662 /// Is this a `..` pattern?
663 pub fn is_rest(&self) -> bool {
664 matches!(self.kind, PatKind::Rest)
668 /// A single field in a struct pattern.
670 /// Patterns like the fields of `Foo { x, ref y, ref mut z }`
671 /// are treated the same as `x: x, y: ref y, z: ref mut z`,
672 /// except when `is_shorthand` is true.
673 #[derive(Clone, Encodable, Decodable, Debug)]
674 pub struct PatField {
675 /// The identifier for the field.
677 /// The pattern the field is destructured to.
679 pub is_shorthand: bool,
683 pub is_placeholder: bool,
686 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
687 pub enum BindingMode {
692 #[derive(Clone, Encodable, Decodable, Debug)]
695 Included(RangeSyntax),
700 #[derive(Clone, Encodable, Decodable, Debug)]
701 pub enum RangeSyntax {
708 /// All the different flavors of pattern that Rust recognizes.
709 #[derive(Clone, Encodable, Decodable, Debug)]
711 /// Represents a wildcard pattern (`_`).
714 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
715 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
716 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
717 /// during name resolution.
718 Ident(BindingMode, Ident, Option<P<Pat>>),
720 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
721 /// The `bool` is `true` in the presence of a `..`.
722 Struct(Option<QSelf>, Path, Vec<PatField>, /* recovered */ bool),
724 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
725 TupleStruct(Option<QSelf>, Path, Vec<P<Pat>>),
727 /// An or-pattern `A | B | C`.
728 /// Invariant: `pats.len() >= 2`.
731 /// A possibly qualified path pattern.
732 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
733 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
734 /// only legally refer to associated constants.
735 Path(Option<QSelf>, Path),
737 /// A tuple pattern (`(a, b)`).
743 /// A reference pattern (e.g., `&mut (a, b)`).
744 Ref(P<Pat>, Mutability),
749 /// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
750 Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
752 /// A slice pattern `[a, b, c]`.
755 /// A rest pattern `..`.
757 /// Syntactically it is valid anywhere.
759 /// Semantically however, it only has meaning immediately inside:
760 /// - a slice pattern: `[a, .., b]`,
761 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
762 /// - a tuple pattern: `(a, .., b)`,
763 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
765 /// In all of these cases, an additional restriction applies,
766 /// only one rest pattern may occur in the pattern sequences.
769 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
772 /// A macro pattern; pre-expansion.
776 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
777 #[derive(HashStable_Generic, Encodable, Decodable)]
778 pub enum Mutability {
784 pub fn invert(self) -> Self {
786 Mutability::Mut => Mutability::Not,
787 Mutability::Not => Mutability::Mut,
791 pub fn prefix_str(&self) -> &'static str {
793 Mutability::Mut => "mut ",
794 Mutability::Not => "",
799 /// The kind of borrow in an `AddrOf` expression,
800 /// e.g., `&place` or `&raw const place`.
801 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
802 #[derive(Encodable, Decodable, HashStable_Generic)]
803 pub enum BorrowKind {
804 /// A normal borrow, `&$expr` or `&mut $expr`.
805 /// The resulting type is either `&'a T` or `&'a mut T`
806 /// where `T = typeof($expr)` and `'a` is some lifetime.
808 /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
809 /// The resulting type is either `*const T` or `*mut T`
810 /// where `T = typeof($expr)`.
814 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
816 /// The `+` operator (addition)
818 /// The `-` operator (subtraction)
820 /// The `*` operator (multiplication)
822 /// The `/` operator (division)
824 /// The `%` operator (modulus)
826 /// The `&&` operator (logical and)
828 /// The `||` operator (logical or)
830 /// The `^` operator (bitwise xor)
832 /// The `&` operator (bitwise and)
834 /// The `|` operator (bitwise or)
836 /// The `<<` operator (shift left)
838 /// The `>>` operator (shift right)
840 /// The `==` operator (equality)
842 /// The `<` operator (less than)
844 /// The `<=` operator (less than or equal to)
846 /// The `!=` operator (not equal to)
848 /// The `>=` operator (greater than or equal to)
850 /// The `>` operator (greater than)
855 pub fn to_string(&self) -> &'static str {
878 pub fn lazy(&self) -> bool {
879 matches!(self, BinOpKind::And | BinOpKind::Or)
882 pub fn is_comparison(&self) -> bool {
884 // Note for developers: please keep this as is;
885 // we want compilation to fail if another variant is added.
887 Eq | Lt | Le | Ne | Gt | Ge => true,
888 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
893 pub type BinOp = Spanned<BinOpKind>;
897 /// Note that `&data` is not an operator, it's an `AddrOf` expression.
898 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
900 /// The `*` operator for dereferencing
902 /// The `!` operator for logical inversion
904 /// The `-` operator for negation
909 pub fn to_string(op: UnOp) -> &'static str {
919 #[derive(Clone, Encodable, Decodable, Debug)]
927 pub fn has_trailing_semicolon(&self) -> bool {
929 StmtKind::Semi(_) => true,
930 StmtKind::MacCall(mac) => matches!(mac.style, MacStmtStyle::Semicolon),
935 /// Converts a parsed `Stmt` to a `Stmt` with
936 /// a trailing semicolon.
938 /// This only modifies the parsed AST struct, not the attached
939 /// `LazyTokenStream`. The parser is responsible for calling
940 /// `CreateTokenStream::add_trailing_semi` when there is actually
941 /// a semicolon in the tokenstream.
942 pub fn add_trailing_semicolon(mut self) -> Self {
943 self.kind = match self.kind {
944 StmtKind::Expr(expr) => StmtKind::Semi(expr),
945 StmtKind::MacCall(mac) => {
946 StmtKind::MacCall(mac.map(|MacCallStmt { mac, style: _, attrs, tokens }| {
947 MacCallStmt { mac, style: MacStmtStyle::Semicolon, attrs, tokens }
956 pub fn is_item(&self) -> bool {
957 matches!(self.kind, StmtKind::Item(_))
960 pub fn is_expr(&self) -> bool {
961 matches!(self.kind, StmtKind::Expr(_))
965 #[derive(Clone, Encodable, Decodable, Debug)]
967 /// A local (let) binding.
969 /// An item definition.
971 /// Expr without trailing semi-colon.
973 /// Expr with a trailing semi-colon.
975 /// Just a trailing semi-colon.
978 MacCall(P<MacCallStmt>),
981 #[derive(Clone, Encodable, Decodable, Debug)]
982 pub struct MacCallStmt {
984 pub style: MacStmtStyle,
986 pub tokens: Option<LazyTokenStream>,
989 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
990 pub enum MacStmtStyle {
991 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
992 /// `foo!(...);`, `foo![...];`).
994 /// The macro statement had braces (e.g., `foo! { ... }`).
996 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
997 /// `foo!(...)`). All of these will end up being converted into macro
1002 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
1003 #[derive(Clone, Encodable, Decodable, Debug)]
1007 pub ty: Option<P<Ty>>,
1008 pub kind: LocalKind,
1011 pub tokens: Option<LazyTokenStream>,
1014 #[derive(Clone, Encodable, Decodable, Debug)]
1015 pub enum LocalKind {
1016 /// Local declaration.
1017 /// Example: `let x;`
1019 /// Local declaration with an initializer.
1020 /// Example: `let x = y;`
1022 /// Local declaration with an initializer and an `else` clause.
1023 /// Example: `let Some(x) = y else { return };`
1024 InitElse(P<Expr>, P<Block>),
1028 pub fn init(&self) -> Option<&Expr> {
1031 Self::Init(i) | Self::InitElse(i, _) => Some(i),
1035 pub fn init_else_opt(&self) -> Option<(&Expr, Option<&Block>)> {
1038 Self::Init(init) => Some((init, None)),
1039 Self::InitElse(init, els) => Some((init, Some(els))),
1044 /// An arm of a 'match'.
1046 /// E.g., `0..=10 => { println!("match!") }` as in
1050 /// 0..=10 => { println!("match!") },
1051 /// _ => { println!("no match!") },
1054 #[derive(Clone, Encodable, Decodable, Debug)]
1057 /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
1059 /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
1060 pub guard: Option<P<Expr>>,
1065 pub is_placeholder: bool,
1068 /// A single field in a struct expression, e.g. `x: value` and `y` in `Foo { x: value, y }`.
1069 #[derive(Clone, Encodable, Decodable, Debug)]
1070 pub struct ExprField {
1076 pub is_shorthand: bool,
1077 pub is_placeholder: bool,
1080 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1081 pub enum BlockCheckMode {
1083 Unsafe(UnsafeSource),
1086 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1087 pub enum UnsafeSource {
1092 /// A constant (expression) that's not an item or associated item,
1093 /// but needs its own `DefId` for type-checking, const-eval, etc.
1094 /// These are usually found nested inside types (e.g., array lengths)
1095 /// or expressions (e.g., repeat counts), and also used to define
1096 /// explicit discriminant values for enum variants.
1097 #[derive(Clone, Encodable, Decodable, Debug)]
1098 pub struct AnonConst {
1104 #[derive(Clone, Encodable, Decodable, Debug)]
1110 pub tokens: Option<LazyTokenStream>,
1114 /// Returns `true` if this expression would be valid somewhere that expects a value;
1115 /// for example, an `if` condition.
1116 pub fn returns(&self) -> bool {
1117 if let ExprKind::Block(ref block, _) = self.kind {
1118 match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
1120 Some(StmtKind::Expr(_)) => true,
1121 // Last statement is an explicit return?
1122 Some(StmtKind::Semi(expr)) => matches!(expr.kind, ExprKind::Ret(_)),
1123 // This is a block that doesn't end in either an implicit or explicit return.
1127 // This is not a block, it is a value.
1132 /// Is this expr either `N`, or `{ N }`.
1134 /// If this is not the case, name resolution does not resolve `N` when using
1135 /// `min_const_generics` as more complex expressions are not supported.
1136 pub fn is_potential_trivial_const_param(&self) -> bool {
1137 let this = if let ExprKind::Block(ref block, None) = self.kind {
1138 if block.stmts.len() == 1 {
1139 if let StmtKind::Expr(ref expr) = block.stmts[0].kind { expr } else { self }
1147 if let ExprKind::Path(None, ref path) = this.kind {
1148 if path.segments.len() == 1 && path.segments[0].args.is_none() {
1156 pub fn to_bound(&self) -> Option<GenericBound> {
1158 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1159 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1160 TraitBoundModifier::None,
1166 pub fn peel_parens(&self) -> &Expr {
1167 let mut expr = self;
1168 while let ExprKind::Paren(inner) = &expr.kind {
1174 /// Attempts to reparse as `Ty` (for diagnostic purposes).
1175 pub fn to_ty(&self) -> Option<P<Ty>> {
1176 let kind = match &self.kind {
1177 // Trivial conversions.
1178 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1179 ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
1181 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1183 ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
1184 expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
1187 ExprKind::Repeat(expr, expr_len) => {
1188 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1191 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1193 ExprKind::Tup(exprs) => {
1194 let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
1198 // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
1199 // then type of result is trait object.
1200 // Otherwise we don't assume the result type.
1201 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1202 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1203 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1209 ExprKind::Underscore => TyKind::Infer,
1211 // This expression doesn't look like a type syntactically.
1215 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
1218 pub fn precedence(&self) -> ExprPrecedence {
1220 ExprKind::Box(_) => ExprPrecedence::Box,
1221 ExprKind::Array(_) => ExprPrecedence::Array,
1222 ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
1223 ExprKind::Call(..) => ExprPrecedence::Call,
1224 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1225 ExprKind::Tup(_) => ExprPrecedence::Tup,
1226 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1227 ExprKind::Unary(..) => ExprPrecedence::Unary,
1228 ExprKind::Lit(_) => ExprPrecedence::Lit,
1229 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1230 ExprKind::Let(..) => ExprPrecedence::Let,
1231 ExprKind::If(..) => ExprPrecedence::If,
1232 ExprKind::While(..) => ExprPrecedence::While,
1233 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1234 ExprKind::Loop(..) => ExprPrecedence::Loop,
1235 ExprKind::Match(..) => ExprPrecedence::Match,
1236 ExprKind::Closure(..) => ExprPrecedence::Closure,
1237 ExprKind::Block(..) => ExprPrecedence::Block,
1238 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1239 ExprKind::Async(..) => ExprPrecedence::Async,
1240 ExprKind::Await(..) => ExprPrecedence::Await,
1241 ExprKind::Assign(..) => ExprPrecedence::Assign,
1242 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1243 ExprKind::Field(..) => ExprPrecedence::Field,
1244 ExprKind::Index(..) => ExprPrecedence::Index,
1245 ExprKind::Range(..) => ExprPrecedence::Range,
1246 ExprKind::Underscore => ExprPrecedence::Path,
1247 ExprKind::Path(..) => ExprPrecedence::Path,
1248 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1249 ExprKind::Break(..) => ExprPrecedence::Break,
1250 ExprKind::Continue(..) => ExprPrecedence::Continue,
1251 ExprKind::Ret(..) => ExprPrecedence::Ret,
1252 ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
1253 ExprKind::MacCall(..) => ExprPrecedence::Mac,
1254 ExprKind::Struct(..) => ExprPrecedence::Struct,
1255 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1256 ExprKind::Paren(..) => ExprPrecedence::Paren,
1257 ExprKind::Try(..) => ExprPrecedence::Try,
1258 ExprKind::Yield(..) => ExprPrecedence::Yield,
1259 ExprKind::Yeet(..) => ExprPrecedence::Yeet,
1260 ExprKind::Err => ExprPrecedence::Err,
1264 pub fn take(&mut self) -> Self {
1269 kind: ExprKind::Err,
1271 attrs: AttrVec::new(),
1277 // To a first-order approximation, is this a pattern
1278 pub fn is_approximately_pattern(&self) -> bool {
1279 match &self.peel_parens().kind {
1281 | ExprKind::Array(_)
1282 | ExprKind::Call(_, _)
1285 | ExprKind::Range(_, _, _)
1286 | ExprKind::Underscore
1287 | ExprKind::Path(_, _)
1288 | ExprKind::Struct(_) => true,
1294 /// Limit types of a range (inclusive or exclusive)
1295 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
1296 pub enum RangeLimits {
1297 /// Inclusive at the beginning, exclusive at the end
1299 /// Inclusive at the beginning and end
1303 #[derive(Clone, Encodable, Decodable, Debug)]
1304 pub enum StructRest {
1309 /// No trailing `..` or expression.
1313 #[derive(Clone, Encodable, Decodable, Debug)]
1314 pub struct StructExpr {
1315 pub qself: Option<QSelf>,
1317 pub fields: Vec<ExprField>,
1318 pub rest: StructRest,
1321 #[derive(Clone, Encodable, Decodable, Debug)]
1323 /// A `box x` expression.
1325 /// An array (`[a, b, c, d]`)
1326 Array(Vec<P<Expr>>),
1327 /// Allow anonymous constants from an inline `const` block
1328 ConstBlock(AnonConst),
1331 /// The first field resolves to the function itself,
1332 /// and the second field is the list of arguments.
1333 /// This also represents calling the constructor of
1334 /// tuple-like ADTs such as tuple structs and enum variants.
1335 Call(P<Expr>, Vec<P<Expr>>),
1336 /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1338 /// The `PathSegment` represents the method name and its generic arguments
1339 /// (within the angle brackets).
1340 /// The standalone `Expr` is the receiver expression.
1341 /// The vector of `Expr` is the arguments.
1342 /// `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1343 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, x, [a, b, c, d])`.
1344 /// This `Span` is the span of the function, without the dot and receiver
1345 /// (e.g. `foo(a, b)` in `x.foo(a, b)`
1346 MethodCall(PathSegment, P<Expr>, Vec<P<Expr>>, Span),
1347 /// A tuple (e.g., `(a, b, c, d)`).
1349 /// A binary operation (e.g., `a + b`, `a * b`).
1350 Binary(BinOp, P<Expr>, P<Expr>),
1351 /// A unary operation (e.g., `!x`, `*x`).
1352 Unary(UnOp, P<Expr>),
1353 /// A literal (e.g., `1`, `"foo"`).
1355 /// A cast (e.g., `foo as f64`).
1356 Cast(P<Expr>, P<Ty>),
1357 /// A type ascription (e.g., `42: usize`).
1358 Type(P<Expr>, P<Ty>),
1359 /// A `let pat = expr` expression that is only semantically allowed in the condition
1360 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1362 /// `Span` represents the whole `let pat = expr` statement.
1363 Let(P<Pat>, P<Expr>, Span),
1364 /// An `if` block, with an optional `else` block.
1366 /// `if expr { block } else { expr }`
1367 If(P<Expr>, P<Block>, Option<P<Expr>>),
1368 /// A while loop, with an optional label.
1370 /// `'label: while expr { block }`
1371 While(P<Expr>, P<Block>, Option<Label>),
1372 /// A `for` loop, with an optional label.
1374 /// `'label: for pat in expr { block }`
1376 /// This is desugared to a combination of `loop` and `match` expressions.
1377 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1378 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1380 /// `'label: loop { block }`
1381 Loop(P<Block>, Option<Label>),
1382 /// A `match` block.
1383 Match(P<Expr>, Vec<Arm>),
1384 /// A closure (e.g., `move |a, b, c| a + b + c`).
1386 /// The final span is the span of the argument block `|...|`.
1387 Closure(ClosureBinder, CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
1388 /// A block (`'label: { ... }`).
1389 Block(P<Block>, Option<Label>),
1390 /// An async block (`async move { ... }`).
1392 /// The `NodeId` is the `NodeId` for the closure that results from
1393 /// desugaring an async block, just like the NodeId field in the
1394 /// `Async::Yes` variant. This is necessary in order to create a def for the
1395 /// closure which can be used as a parent of any child defs. Defs
1396 /// created during lowering cannot be made the parent of any other
1397 /// preexisting defs.
1398 Async(CaptureBy, NodeId, P<Block>),
1399 /// An await expression (`my_future.await`).
1402 /// A try block (`try { ... }`).
1405 /// An assignment (`a = foo()`).
1406 /// The `Span` argument is the span of the `=` token.
1407 Assign(P<Expr>, P<Expr>, Span),
1408 /// An assignment with an operator.
1411 AssignOp(BinOp, P<Expr>, P<Expr>),
1412 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1413 Field(P<Expr>, Ident),
1414 /// An indexing operation (e.g., `foo[2]`).
1415 Index(P<Expr>, P<Expr>),
1416 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assignment).
1417 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1418 /// An underscore, used in destructuring assignment to ignore a value.
1421 /// Variable reference, possibly containing `::` and/or type
1422 /// parameters (e.g., `foo::bar::<baz>`).
1424 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1425 Path(Option<QSelf>, Path),
1427 /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
1428 AddrOf(BorrowKind, Mutability, P<Expr>),
1429 /// A `break`, with an optional label to break, and an optional expression.
1430 Break(Option<Label>, Option<P<Expr>>),
1431 /// A `continue`, with an optional label.
1432 Continue(Option<Label>),
1433 /// A `return`, with an optional value to be returned.
1434 Ret(Option<P<Expr>>),
1436 /// Output of the `asm!()` macro.
1437 InlineAsm(P<InlineAsm>),
1439 /// A macro invocation; pre-expansion.
1440 MacCall(P<MacCall>),
1442 /// A struct literal expression.
1444 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
1445 Struct(P<StructExpr>),
1447 /// An array literal constructed from one repeated element.
1449 /// E.g., `[1; 5]`. The expression is the element to be
1450 /// repeated; the constant is the number of times to repeat it.
1451 Repeat(P<Expr>, AnonConst),
1453 /// No-op: used solely so we can pretty-print faithfully.
1456 /// A try expression (`expr?`).
1459 /// A `yield`, with an optional value to be yielded.
1460 Yield(Option<P<Expr>>),
1462 /// A `do yeet` (aka `throw`/`fail`/`bail`/`raise`/whatever),
1463 /// with an optional value to be returned.
1464 Yeet(Option<P<Expr>>),
1466 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1470 /// The explicit `Self` type in a "qualified path". The actual
1471 /// path, including the trait and the associated item, is stored
1472 /// separately. `position` represents the index of the associated
1473 /// item qualified with this `Self` type.
1475 /// ```ignore (only-for-syntax-highlight)
1476 /// <Vec<T> as a::b::Trait>::AssociatedItem
1477 /// ^~~~~ ~~~~~~~~~~~~~~^
1480 /// <Vec<T>>::AssociatedItem
1484 #[derive(Clone, Encodable, Decodable, Debug)]
1488 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1489 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1490 /// 0`, this is an empty span.
1491 pub path_span: Span,
1492 pub position: usize,
1495 /// A capture clause used in closures and `async` blocks.
1496 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1497 pub enum CaptureBy {
1498 /// `move |x| y + x`.
1500 /// `move` keyword was not specified.
1504 /// The movability of a generator / closure literal:
1505 /// whether a generator contains self-references, causing it to be `!Unpin`.
1506 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
1507 #[derive(HashStable_Generic)]
1508 pub enum Movability {
1509 /// May contain self-references, `!Unpin`.
1511 /// Must not contain self-references, `Unpin`.
1515 /// Closure lifetime binder, `for<'a, 'b>` in `for<'a, 'b> |_: &'a (), _: &'b ()|`.
1516 #[derive(Clone, Encodable, Decodable, Debug)]
1517 pub enum ClosureBinder {
1518 /// The binder is not present, all closure lifetimes are inferred.
1520 /// The binder is present.
1522 /// Span of the whole `for<>` clause
1525 /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
1526 /// ^^^^^^^^^^^ -- this
1530 /// Lifetimes in the `for<>` closure
1533 /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
1536 generic_params: P<[GenericParam]>,
1540 /// Represents a macro invocation. The `path` indicates which macro
1541 /// is being invoked, and the `args` are arguments passed to it.
1542 #[derive(Clone, Encodable, Decodable, Debug)]
1543 pub struct MacCall {
1545 pub args: P<MacArgs>,
1546 pub prior_type_ascription: Option<(Span, bool)>,
1550 pub fn span(&self) -> Span {
1551 self.path.span.to(self.args.span().unwrap_or(self.path.span))
1555 /// Arguments passed to an attribute or a function-like macro.
1556 #[derive(Clone, Encodable, Decodable, Debug)]
1558 /// No arguments - `#[attr]`.
1560 /// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
1561 Delimited(DelimSpan, MacDelimiter, TokenStream),
1562 /// Arguments of a key-value attribute - `#[attr = "value"]`.
1564 /// Span of the `=` token.
1571 // The RHS of a `MacArgs::Eq` starts out as an expression. Once macro expansion
1572 // is completed, all cases end up either as a literal, which is the form used
1573 // after lowering to HIR, or as an error.
1574 #[derive(Clone, Encodable, Decodable, Debug)]
1575 pub enum MacArgsEq {
1581 pub fn delim(&self) -> Option<Delimiter> {
1583 MacArgs::Delimited(_, delim, _) => Some(delim.to_token()),
1584 MacArgs::Empty | MacArgs::Eq(..) => None,
1588 pub fn span(&self) -> Option<Span> {
1590 MacArgs::Empty => None,
1591 MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
1592 MacArgs::Eq(eq_span, MacArgsEq::Ast(expr)) => Some(eq_span.to(expr.span)),
1593 MacArgs::Eq(_, MacArgsEq::Hir(lit)) => {
1594 unreachable!("in literal form when getting span: {:?}", lit);
1599 /// Tokens inside the delimiters or after `=`.
1600 /// Proc macros see these tokens, for example.
1601 pub fn inner_tokens(&self) -> TokenStream {
1603 MacArgs::Empty => TokenStream::default(),
1604 MacArgs::Delimited(.., tokens) => tokens.clone(),
1605 MacArgs::Eq(_, MacArgsEq::Ast(expr)) => TokenStream::from_ast(expr),
1606 MacArgs::Eq(_, MacArgsEq::Hir(lit)) => {
1607 unreachable!("in literal form when getting inner tokens: {:?}", lit)
1612 /// Whether a macro with these arguments needs a semicolon
1613 /// when used as a standalone item or statement.
1614 pub fn need_semicolon(&self) -> bool {
1615 !matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
1619 impl<CTX> HashStable<CTX> for MacArgs
1621 CTX: crate::HashStableContext,
1623 fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
1624 mem::discriminant(self).hash_stable(ctx, hasher);
1626 MacArgs::Empty => {}
1627 MacArgs::Delimited(dspan, delim, tokens) => {
1628 dspan.hash_stable(ctx, hasher);
1629 delim.hash_stable(ctx, hasher);
1630 tokens.hash_stable(ctx, hasher);
1632 MacArgs::Eq(_eq_span, MacArgsEq::Ast(expr)) => {
1633 unreachable!("hash_stable {:?}", expr);
1635 MacArgs::Eq(eq_span, MacArgsEq::Hir(lit)) => {
1636 eq_span.hash_stable(ctx, hasher);
1637 lit.hash_stable(ctx, hasher);
1643 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
1644 pub enum MacDelimiter {
1651 pub fn to_token(self) -> Delimiter {
1653 MacDelimiter::Parenthesis => Delimiter::Parenthesis,
1654 MacDelimiter::Bracket => Delimiter::Bracket,
1655 MacDelimiter::Brace => Delimiter::Brace,
1659 pub fn from_token(delim: Delimiter) -> Option<MacDelimiter> {
1661 Delimiter::Parenthesis => Some(MacDelimiter::Parenthesis),
1662 Delimiter::Bracket => Some(MacDelimiter::Bracket),
1663 Delimiter::Brace => Some(MacDelimiter::Brace),
1664 Delimiter::Invisible => None,
1669 /// Represents a macro definition.
1670 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1671 pub struct MacroDef {
1672 pub body: P<MacArgs>,
1673 /// `true` if macro was defined with `macro_rules`.
1674 pub macro_rules: bool,
1677 #[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
1678 #[derive(HashStable_Generic)]
1680 /// A regular string, like `"foo"`.
1682 /// A raw string, like `r##"foo"##`.
1684 /// The value is the number of `#` symbols used.
1689 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1691 /// The original literal token as written in source code.
1692 pub token_lit: token::Lit,
1693 /// The "semantic" representation of the literal lowered from the original tokens.
1694 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1695 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1700 /// Same as `Lit`, but restricted to string literals.
1701 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1703 /// The original literal token as written in source code.
1704 pub style: StrStyle,
1706 pub suffix: Option<Symbol>,
1708 /// The unescaped "semantic" representation of the literal lowered from the original token.
1709 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1710 pub symbol_unescaped: Symbol,
1714 pub fn as_lit(&self) -> Lit {
1715 let token_kind = match self.style {
1716 StrStyle::Cooked => token::Str,
1717 StrStyle::Raw(n) => token::StrRaw(n),
1720 token_lit: token::Lit::new(token_kind, self.symbol, self.suffix),
1722 kind: LitKind::Str(self.symbol_unescaped, self.style),
1727 /// Type of the integer literal based on provided suffix.
1728 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1729 #[derive(HashStable_Generic)]
1730 pub enum LitIntType {
1739 /// Type of the float literal based on provided suffix.
1740 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1741 #[derive(HashStable_Generic)]
1742 pub enum LitFloatType {
1743 /// A float literal with a suffix (`1f32` or `1E10f32`).
1745 /// A float literal without a suffix (`1.0 or 1.0E10`).
1751 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
1752 #[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
1754 /// A string literal (`"foo"`).
1755 Str(Symbol, StrStyle),
1756 /// A byte string (`b"foo"`).
1758 /// A byte char (`b'f'`).
1760 /// A character literal (`'a'`).
1762 /// An integer literal (`1`).
1763 Int(u128, LitIntType),
1764 /// A float literal (`1f64` or `1E10f64`).
1765 Float(Symbol, LitFloatType),
1766 /// A boolean literal.
1768 /// Placeholder for a literal that wasn't well-formed in some way.
1773 /// Returns `true` if this literal is a string.
1774 pub fn is_str(&self) -> bool {
1775 matches!(self, LitKind::Str(..))
1778 /// Returns `true` if this literal is byte literal string.
1779 pub fn is_bytestr(&self) -> bool {
1780 matches!(self, LitKind::ByteStr(_))
1783 /// Returns `true` if this is a numeric literal.
1784 pub fn is_numeric(&self) -> bool {
1785 matches!(self, LitKind::Int(..) | LitKind::Float(..))
1788 /// Returns `true` if this literal has no suffix.
1789 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1790 pub fn is_unsuffixed(&self) -> bool {
1794 /// Returns `true` if this literal has a suffix.
1795 pub fn is_suffixed(&self) -> bool {
1797 // suffixed variants
1798 LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
1799 | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
1800 // unsuffixed variants
1802 | LitKind::ByteStr(..)
1805 | LitKind::Int(_, LitIntType::Unsuffixed)
1806 | LitKind::Float(_, LitFloatType::Unsuffixed)
1808 | LitKind::Err(..) => false,
1813 // N.B., If you change this, you'll probably want to change the corresponding
1814 // type structure in `middle/ty.rs` as well.
1815 #[derive(Clone, Encodable, Decodable, Debug)]
1818 pub mutbl: Mutability,
1821 /// Represents a function's signature in a trait declaration,
1822 /// trait implementation, or free function.
1823 #[derive(Clone, Encodable, Decodable, Debug)]
1825 pub header: FnHeader,
1826 pub decl: P<FnDecl>,
1830 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1831 #[derive(Encodable, Decodable, HashStable_Generic)]
1838 pub fn name_str(self) -> &'static str {
1840 FloatTy::F32 => "f32",
1841 FloatTy::F64 => "f64",
1845 pub fn name(self) -> Symbol {
1847 FloatTy::F32 => sym::f32,
1848 FloatTy::F64 => sym::f64,
1853 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1854 #[derive(Encodable, Decodable, HashStable_Generic)]
1865 pub fn name_str(&self) -> &'static str {
1867 IntTy::Isize => "isize",
1869 IntTy::I16 => "i16",
1870 IntTy::I32 => "i32",
1871 IntTy::I64 => "i64",
1872 IntTy::I128 => "i128",
1876 pub fn name(&self) -> Symbol {
1878 IntTy::Isize => sym::isize,
1879 IntTy::I8 => sym::i8,
1880 IntTy::I16 => sym::i16,
1881 IntTy::I32 => sym::i32,
1882 IntTy::I64 => sym::i64,
1883 IntTy::I128 => sym::i128,
1888 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
1889 #[derive(Encodable, Decodable, HashStable_Generic)]
1900 pub fn name_str(&self) -> &'static str {
1902 UintTy::Usize => "usize",
1904 UintTy::U16 => "u16",
1905 UintTy::U32 => "u32",
1906 UintTy::U64 => "u64",
1907 UintTy::U128 => "u128",
1911 pub fn name(&self) -> Symbol {
1913 UintTy::Usize => sym::usize,
1914 UintTy::U8 => sym::u8,
1915 UintTy::U16 => sym::u16,
1916 UintTy::U32 => sym::u32,
1917 UintTy::U64 => sym::u64,
1918 UintTy::U128 => sym::u128,
1923 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1924 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1925 #[derive(Clone, Encodable, Decodable, Debug)]
1926 pub struct AssocConstraint {
1929 pub gen_args: Option<GenericArgs>,
1930 pub kind: AssocConstraintKind,
1934 /// The kinds of an `AssocConstraint`.
1935 #[derive(Clone, Encodable, Decodable, Debug)]
1941 impl From<P<Ty>> for Term {
1942 fn from(v: P<Ty>) -> Self {
1947 impl From<AnonConst> for Term {
1948 fn from(v: AnonConst) -> Self {
1953 /// The kinds of an `AssocConstraint`.
1954 #[derive(Clone, Encodable, Decodable, Debug)]
1955 pub enum AssocConstraintKind {
1956 /// E.g., `A = Bar`, `A = 3` in `Foo<A = Bar>` where A is an associated type.
1957 Equality { term: Term },
1958 /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
1959 Bound { bounds: GenericBounds },
1962 #[derive(Encodable, Decodable, Debug)]
1967 pub tokens: Option<LazyTokenStream>,
1971 fn clone(&self) -> Self {
1972 ensure_sufficient_stack(|| Self {
1974 kind: self.kind.clone(),
1976 tokens: self.tokens.clone(),
1982 pub fn peel_refs(&self) -> &Self {
1983 let mut final_ty = self;
1984 while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
1991 #[derive(Clone, Encodable, Decodable, Debug)]
1992 pub struct BareFnTy {
1993 pub unsafety: Unsafe,
1995 pub generic_params: Vec<GenericParam>,
1996 pub decl: P<FnDecl>,
1997 /// Span of the `fn(...) -> ...` part.
1998 pub decl_span: Span,
2001 /// The various kinds of type recognized by the compiler.
2002 #[derive(Clone, Encodable, Decodable, Debug)]
2004 /// A variable-length slice (`[T]`).
2006 /// A fixed length array (`[T; n]`).
2007 Array(P<Ty>, AnonConst),
2008 /// A raw pointer (`*const T` or `*mut T`).
2010 /// A reference (`&'a T` or `&'a mut T`).
2011 Rptr(Option<Lifetime>, MutTy),
2012 /// A bare function (e.g., `fn(usize) -> bool`).
2013 BareFn(P<BareFnTy>),
2014 /// The never type (`!`).
2016 /// A tuple (`(A, B, C, D,...)`).
2018 /// A path (`module::module::...::Type`), optionally
2019 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
2021 /// Type parameters are stored in the `Path` itself.
2022 Path(Option<QSelf>, Path),
2023 /// A trait object type `Bound1 + Bound2 + Bound3`
2024 /// where `Bound` is a trait or a lifetime.
2025 TraitObject(GenericBounds, TraitObjectSyntax),
2026 /// An `impl Bound1 + Bound2 + Bound3` type
2027 /// where `Bound` is a trait or a lifetime.
2029 /// The `NodeId` exists to prevent lowering from having to
2030 /// generate `NodeId`s on the fly, which would complicate
2031 /// the generation of opaque `type Foo = impl Trait` items significantly.
2032 ImplTrait(NodeId, GenericBounds),
2033 /// No-op; kept solely so that we can pretty-print faithfully.
2037 /// This means the type should be inferred instead of it having been
2038 /// specified. This can appear anywhere in a type.
2040 /// Inferred type of a `self` or `&self` argument in a method.
2042 /// A macro in the type position.
2043 MacCall(P<MacCall>),
2044 /// Placeholder for a kind that has failed to be defined.
2046 /// Placeholder for a `va_list`.
2051 pub fn is_implicit_self(&self) -> bool {
2052 matches!(self, TyKind::ImplicitSelf)
2055 pub fn is_unit(&self) -> bool {
2056 matches!(self, TyKind::Tup(tys) if tys.is_empty())
2059 pub fn is_simple_path(&self) -> Option<Symbol> {
2060 if let TyKind::Path(None, Path { segments, .. }) = &self && segments.len() == 1 {
2061 Some(segments[0].ident.name)
2068 /// Syntax used to declare a trait object.
2069 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2070 pub enum TraitObjectSyntax {
2075 /// Inline assembly operand explicit register or register class.
2077 /// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
2078 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2079 pub enum InlineAsmRegOrRegClass {
2084 bitflags::bitflags! {
2085 #[derive(Encodable, Decodable, HashStable_Generic)]
2086 pub struct InlineAsmOptions: u16 {
2087 const PURE = 1 << 0;
2088 const NOMEM = 1 << 1;
2089 const READONLY = 1 << 2;
2090 const PRESERVES_FLAGS = 1 << 3;
2091 const NORETURN = 1 << 4;
2092 const NOSTACK = 1 << 5;
2093 const ATT_SYNTAX = 1 << 6;
2095 const MAY_UNWIND = 1 << 8;
2099 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
2100 pub enum InlineAsmTemplatePiece {
2102 Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
2105 impl fmt::Display for InlineAsmTemplatePiece {
2106 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2108 Self::String(s) => {
2109 for c in s.chars() {
2111 '{' => f.write_str("{{")?,
2112 '}' => f.write_str("}}")?,
2118 Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
2119 write!(f, "{{{}:{}}}", operand_idx, modifier)
2121 Self::Placeholder { operand_idx, modifier: None, .. } => {
2122 write!(f, "{{{}}}", operand_idx)
2128 impl InlineAsmTemplatePiece {
2129 /// Rebuilds the asm template string from its pieces.
2130 pub fn to_string(s: &[Self]) -> String {
2132 let mut out = String::new();
2134 let _ = write!(out, "{}", p);
2140 /// Inline assembly symbol operands get their own AST node that is somewhat
2141 /// similar to `AnonConst`.
2143 /// The main difference is that we specifically don't assign it `DefId` in
2144 /// `DefCollector`. Instead this is deferred until AST lowering where we
2145 /// lower it to an `AnonConst` (for functions) or a `Path` (for statics)
2146 /// depending on what the path resolves to.
2147 #[derive(Clone, Encodable, Decodable, Debug)]
2148 pub struct InlineAsmSym {
2150 pub qself: Option<QSelf>,
2154 /// Inline assembly operand.
2156 /// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
2157 #[derive(Clone, Encodable, Decodable, Debug)]
2158 pub enum InlineAsmOperand {
2160 reg: InlineAsmRegOrRegClass,
2164 reg: InlineAsmRegOrRegClass,
2166 expr: Option<P<Expr>>,
2169 reg: InlineAsmRegOrRegClass,
2174 reg: InlineAsmRegOrRegClass,
2177 out_expr: Option<P<Expr>>,
2180 anon_const: AnonConst,
2187 /// Inline assembly.
2189 /// E.g., `asm!("NOP");`.
2190 #[derive(Clone, Encodable, Decodable, Debug)]
2191 pub struct InlineAsm {
2192 pub template: Vec<InlineAsmTemplatePiece>,
2193 pub template_strs: Box<[(Symbol, Option<Symbol>, Span)]>,
2194 pub operands: Vec<(InlineAsmOperand, Span)>,
2195 pub clobber_abis: Vec<(Symbol, Span)>,
2196 pub options: InlineAsmOptions,
2197 pub line_spans: Vec<Span>,
2200 /// A parameter in a function header.
2202 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
2203 #[derive(Clone, Encodable, Decodable, Debug)]
2210 pub is_placeholder: bool,
2213 /// Alternative representation for `Arg`s describing `self` parameter of methods.
2215 /// E.g., `&mut self` as in `fn foo(&mut self)`.
2216 #[derive(Clone, Encodable, Decodable, Debug)]
2218 /// `self`, `mut self`
2220 /// `&'lt self`, `&'lt mut self`
2221 Region(Option<Lifetime>, Mutability),
2222 /// `self: TYPE`, `mut self: TYPE`
2223 Explicit(P<Ty>, Mutability),
2226 pub type ExplicitSelf = Spanned<SelfKind>;
2229 /// Attempts to cast parameter to `ExplicitSelf`.
2230 pub fn to_self(&self) -> Option<ExplicitSelf> {
2231 if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
2232 if ident.name == kw::SelfLower {
2233 return match self.ty.kind {
2234 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
2235 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
2236 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
2239 self.pat.span.to(self.ty.span),
2240 SelfKind::Explicit(self.ty.clone(), mutbl),
2248 /// Returns `true` if parameter is `self`.
2249 pub fn is_self(&self) -> bool {
2250 if let PatKind::Ident(_, ident, _) = self.pat.kind {
2251 ident.name == kw::SelfLower
2257 /// Builds a `Param` object from `ExplicitSelf`.
2258 pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
2259 let span = eself.span.to(eself_ident.span);
2260 let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
2261 let param = |mutbl, ty| Param {
2265 kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
2272 is_placeholder: false,
2275 SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
2276 SelfKind::Value(mutbl) => param(mutbl, infer_ty),
2277 SelfKind::Region(lt, mutbl) => param(
2281 kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
2290 /// A signature (not the body) of a function declaration.
2292 /// E.g., `fn foo(bar: baz)`.
2294 /// Please note that it's different from `FnHeader` structure
2295 /// which contains metadata about function safety, asyncness, constness and ABI.
2296 #[derive(Clone, Encodable, Decodable, Debug)]
2298 pub inputs: Vec<Param>,
2299 pub output: FnRetTy,
2303 pub fn has_self(&self) -> bool {
2304 self.inputs.get(0).map_or(false, Param::is_self)
2306 pub fn c_variadic(&self) -> bool {
2307 self.inputs.last().map_or(false, |arg| matches!(arg.ty.kind, TyKind::CVarArgs))
2311 /// Is the trait definition an auto trait?
2312 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2318 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2319 #[derive(HashStable_Generic)]
2325 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2327 Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
2332 pub fn is_async(self) -> bool {
2333 matches!(self, Async::Yes { .. })
2336 /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
2337 pub fn opt_return_id(self) -> Option<NodeId> {
2339 Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
2345 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2346 #[derive(HashStable_Generic)]
2352 /// Item defaultness.
2353 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
2354 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2355 pub enum Defaultness {
2360 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
2361 pub enum ImplPolarity {
2362 /// `impl Trait for Type`
2364 /// `impl !Trait for Type`
2368 impl fmt::Debug for ImplPolarity {
2369 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2371 ImplPolarity::Positive => "positive".fmt(f),
2372 ImplPolarity::Negative(_) => "negative".fmt(f),
2377 #[derive(Clone, Encodable, Decodable, Debug)]
2379 /// Returns type is not specified.
2381 /// Functions default to `()` and closures default to inference.
2382 /// Span points to where return type would be inserted.
2384 /// Everything else.
2389 pub fn span(&self) -> Span {
2391 FnRetTy::Default(span) => span,
2392 FnRetTy::Ty(ref ty) => ty.span,
2397 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
2403 /// Module item kind.
2404 #[derive(Clone, Encodable, Decodable, Debug)]
2406 /// Module with inlined definition `mod foo { ... }`,
2407 /// or with definition outlined to a separate file `mod foo;` and already loaded from it.
2408 /// The inner span is from the first token past `{` to the last token until `}`,
2409 /// or from the first to the last token in the loaded file.
2410 Loaded(Vec<P<Item>>, Inline, ModSpans),
2411 /// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
2415 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2416 pub struct ModSpans {
2417 /// `inner_span` covers the body of the module; for a file module, its the whole file.
2418 /// For an inline module, its the span inside the `{ ... }`, not including the curly braces.
2419 pub inner_span: Span,
2420 pub inject_use_span: Span,
2423 impl Default for ModSpans {
2424 fn default() -> ModSpans {
2425 ModSpans { inner_span: Default::default(), inject_use_span: Default::default() }
2429 /// Foreign module declaration.
2431 /// E.g., `extern { .. }` or `extern "C" { .. }`.
2432 #[derive(Clone, Encodable, Decodable, Debug)]
2433 pub struct ForeignMod {
2434 /// `unsafe` keyword accepted syntactically for macro DSLs, but not
2435 /// semantically by Rust.
2436 pub unsafety: Unsafe,
2437 pub abi: Option<StrLit>,
2438 pub items: Vec<P<ForeignItem>>,
2441 #[derive(Clone, Encodable, Decodable, Debug)]
2442 pub struct EnumDef {
2443 pub variants: Vec<Variant>,
2446 #[derive(Clone, Encodable, Decodable, Debug)]
2447 pub struct Variant {
2448 /// Attributes of the variant.
2450 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2454 /// The visibility of the variant. Syntactically accepted but not semantically.
2455 pub vis: Visibility,
2456 /// Name of the variant.
2459 /// Fields and constructor id of the variant.
2460 pub data: VariantData,
2461 /// Explicit discriminant, e.g., `Foo = 1`.
2462 pub disr_expr: Option<AnonConst>,
2463 /// Is a macro placeholder
2464 pub is_placeholder: bool,
2467 /// Part of `use` item to the right of its prefix.
2468 #[derive(Clone, Encodable, Decodable, Debug)]
2469 pub enum UseTreeKind {
2470 /// `use prefix` or `use prefix as rename`
2472 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2474 Simple(Option<Ident>, NodeId, NodeId),
2475 /// `use prefix::{...}`
2476 Nested(Vec<(UseTree, NodeId)>),
2481 /// A tree of paths sharing common prefixes.
2482 /// Used in `use` items both at top-level and inside of braces in import groups.
2483 #[derive(Clone, Encodable, Decodable, Debug)]
2484 pub struct UseTree {
2486 pub kind: UseTreeKind,
2491 pub fn ident(&self) -> Ident {
2493 UseTreeKind::Simple(Some(rename), ..) => rename,
2494 UseTreeKind::Simple(None, ..) => {
2495 self.prefix.segments.last().expect("empty prefix in a simple import").ident
2497 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2502 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2503 /// are contained as statements within items. These two cases need to be
2504 /// distinguished for pretty-printing.
2505 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
2506 pub enum AttrStyle {
2511 rustc_index::newtype_index! {
2514 DEBUG_FORMAT = "AttrId({})"
2518 impl<S: Encoder> Encodable<S> for AttrId {
2519 fn encode(&self, _s: &mut S) {}
2522 impl<D: Decoder> Decodable<D> for AttrId {
2523 fn decode(_: &mut D) -> AttrId {
2524 crate::attr::mk_attr_id()
2528 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2529 pub struct AttrItem {
2532 pub tokens: Option<LazyTokenStream>,
2535 /// A list of attributes.
2536 pub type AttrVec = ThinVec<Attribute>;
2538 /// Metadata associated with an item.
2539 #[derive(Clone, Encodable, Decodable, Debug)]
2540 pub struct Attribute {
2543 /// Denotes if the attribute decorates the following construct (outer)
2544 /// or the construct this attribute is contained within (inner).
2545 pub style: AttrStyle,
2549 #[derive(Clone, Encodable, Decodable, Debug)]
2550 pub struct NormalAttr {
2552 pub tokens: Option<LazyTokenStream>,
2555 #[derive(Clone, Encodable, Decodable, Debug)]
2557 /// A normal attribute.
2558 Normal(P<NormalAttr>),
2560 /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
2561 /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
2562 /// variant (which is much less compact and thus more expensive).
2563 DocComment(CommentKind, Symbol),
2566 /// `TraitRef`s appear in impls.
2568 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2569 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2570 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2571 /// same as the impl's `NodeId`).
2572 #[derive(Clone, Encodable, Decodable, Debug)]
2573 pub struct TraitRef {
2578 #[derive(Clone, Encodable, Decodable, Debug)]
2579 pub struct PolyTraitRef {
2580 /// The `'a` in `for<'a> Foo<&'a T>`.
2581 pub bound_generic_params: Vec<GenericParam>,
2583 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2584 pub trait_ref: TraitRef,
2590 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2592 bound_generic_params: generic_params,
2593 trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
2599 #[derive(Clone, Encodable, Decodable, Debug)]
2600 pub struct Visibility {
2601 pub kind: VisibilityKind,
2603 pub tokens: Option<LazyTokenStream>,
2606 #[derive(Clone, Encodable, Decodable, Debug)]
2607 pub enum VisibilityKind {
2609 Restricted { path: P<Path>, id: NodeId, shorthand: bool },
2613 impl VisibilityKind {
2614 pub fn is_pub(&self) -> bool {
2615 matches!(self, VisibilityKind::Public)
2619 /// Field definition in a struct, variant or union.
2621 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2622 #[derive(Clone, Encodable, Decodable, Debug)]
2623 pub struct FieldDef {
2627 pub vis: Visibility,
2628 pub ident: Option<Ident>,
2631 pub is_placeholder: bool,
2634 /// Fields and constructor ids of enum variants and structs.
2635 #[derive(Clone, Encodable, Decodable, Debug)]
2636 pub enum VariantData {
2639 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2640 Struct(Vec<FieldDef>, bool),
2643 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2644 Tuple(Vec<FieldDef>, NodeId),
2647 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2652 /// Return the fields of this variant.
2653 pub fn fields(&self) -> &[FieldDef] {
2655 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
2660 /// Return the `NodeId` of this variant's constructor, if it has one.
2661 pub fn ctor_id(&self) -> Option<NodeId> {
2663 VariantData::Struct(..) => None,
2664 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2669 /// An item definition.
2670 #[derive(Clone, Encodable, Decodable, Debug)]
2671 pub struct Item<K = ItemKind> {
2675 pub vis: Visibility,
2676 /// The name of the item.
2677 /// It might be a dummy name in case of anonymous items.
2682 /// Original tokens this item was parsed from. This isn't necessarily
2683 /// available for all items, although over time more and more items should
2684 /// have this be `Some`. Right now this is primarily used for procedural
2685 /// macros, notably custom attributes.
2687 /// Note that the tokens here do not include the outer attributes, but will
2688 /// include inner attributes.
2689 pub tokens: Option<LazyTokenStream>,
2693 /// Return the span that encompasses the attributes.
2694 pub fn span_with_attributes(&self) -> Span {
2695 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2699 /// `extern` qualifier on a function item or function type.
2700 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2704 Explicit(StrLit, Span),
2708 pub fn from_abi(abi: Option<StrLit>, span: Span) -> Extern {
2710 Some(name) => Extern::Explicit(name, span),
2711 None => Extern::Implicit(span),
2716 /// A function header.
2718 /// All the information between the visibility and the name of the function is
2719 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2720 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2721 pub struct FnHeader {
2722 pub unsafety: Unsafe,
2723 pub asyncness: Async,
2724 pub constness: Const,
2729 /// Does this function header have any qualifiers or is it empty?
2730 pub fn has_qualifiers(&self) -> bool {
2731 let Self { unsafety, asyncness, constness, ext } = self;
2732 matches!(unsafety, Unsafe::Yes(_))
2733 || asyncness.is_async()
2734 || matches!(constness, Const::Yes(_))
2735 || !matches!(ext, Extern::None)
2739 impl Default for FnHeader {
2740 fn default() -> FnHeader {
2742 unsafety: Unsafe::No,
2743 asyncness: Async::No,
2744 constness: Const::No,
2750 #[derive(Clone, Encodable, Decodable, Debug)]
2752 pub unsafety: Unsafe,
2753 pub is_auto: IsAuto,
2754 pub generics: Generics,
2755 pub bounds: GenericBounds,
2756 pub items: Vec<P<AssocItem>>,
2759 /// The location of a where clause on a `TyAlias` (`Span`) and whether there was
2760 /// a `where` keyword (`bool`). This is split out from `WhereClause`, since there
2761 /// are two locations for where clause on type aliases, but their predicates
2762 /// are concatenated together.
2764 /// Take this example:
2765 /// ```ignore (only-for-syntax-highlight)
2767 /// type Assoc<'a, 'b> where Self: 'a, Self: 'b;
2769 /// impl Foo for () {
2770 /// type Assoc<'a, 'b> where Self: 'a = () where Self: 'b;
2771 /// // ^^^^^^^^^^^^^^ first where clause
2772 /// // ^^^^^^^^^^^^^^ second where clause
2776 /// If there is no where clause, then this is `false` with `DUMMY_SP`.
2777 #[derive(Copy, Clone, Encodable, Decodable, Debug, Default)]
2778 pub struct TyAliasWhereClause(pub bool, pub Span);
2780 #[derive(Clone, Encodable, Decodable, Debug)]
2781 pub struct TyAlias {
2782 pub defaultness: Defaultness,
2783 pub generics: Generics,
2784 /// The span information for the two where clauses (before equals, after equals)
2785 pub where_clauses: (TyAliasWhereClause, TyAliasWhereClause),
2786 /// The index in `generics.where_clause.predicates` that would split into
2787 /// predicates from the where clause before the equals and the predicates
2788 /// from the where clause after the equals
2789 pub where_predicates_split: usize,
2790 pub bounds: GenericBounds,
2791 pub ty: Option<P<Ty>>,
2794 #[derive(Clone, Encodable, Decodable, Debug)]
2796 pub defaultness: Defaultness,
2797 pub unsafety: Unsafe,
2798 pub generics: Generics,
2799 pub constness: Const,
2800 pub polarity: ImplPolarity,
2801 /// The trait being implemented, if any.
2802 pub of_trait: Option<TraitRef>,
2804 pub items: Vec<P<AssocItem>>,
2807 #[derive(Clone, Encodable, Decodable, Debug)]
2809 pub defaultness: Defaultness,
2810 pub generics: Generics,
2812 pub body: Option<P<Block>>,
2815 #[derive(Clone, Encodable, Decodable, Debug)]
2817 /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
2819 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2820 ExternCrate(Option<Symbol>),
2821 /// A use declaration item (`use`).
2823 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2825 /// A static item (`static`).
2827 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2828 Static(P<Ty>, Mutability, Option<P<Expr>>),
2829 /// A constant item (`const`).
2831 /// E.g., `const FOO: i32 = 42;`.
2832 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2833 /// A function declaration (`fn`).
2835 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2837 /// A module declaration (`mod`).
2839 /// E.g., `mod foo;` or `mod foo { .. }`.
2840 /// `unsafe` keyword on modules is accepted syntactically for macro DSLs, but not
2841 /// semantically by Rust.
2842 Mod(Unsafe, ModKind),
2843 /// An external module (`extern`).
2845 /// E.g., `extern {}` or `extern "C" {}`.
2846 ForeignMod(ForeignMod),
2847 /// Module-level inline assembly (from `global_asm!()`).
2848 GlobalAsm(Box<InlineAsm>),
2849 /// A type alias (`type`).
2851 /// E.g., `type Foo = Bar<u8>;`.
2852 TyAlias(Box<TyAlias>),
2853 /// An enum definition (`enum`).
2855 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2856 Enum(EnumDef, Generics),
2857 /// A struct definition (`struct`).
2859 /// E.g., `struct Foo<A> { x: A }`.
2860 Struct(VariantData, Generics),
2861 /// A union definition (`union`).
2863 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2864 Union(VariantData, Generics),
2865 /// A trait declaration (`trait`).
2867 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2871 /// E.g., `trait Foo = Bar + Quux;`.
2872 TraitAlias(Generics, GenericBounds),
2873 /// An implementation.
2875 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2877 /// A macro invocation.
2879 /// E.g., `foo!(..)`.
2880 MacCall(P<MacCall>),
2882 /// A macro definition.
2887 pub fn article(&self) -> &str {
2890 Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
2891 | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
2892 ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
2896 pub fn descr(&self) -> &str {
2898 ItemKind::ExternCrate(..) => "extern crate",
2899 ItemKind::Use(..) => "`use` import",
2900 ItemKind::Static(..) => "static item",
2901 ItemKind::Const(..) => "constant item",
2902 ItemKind::Fn(..) => "function",
2903 ItemKind::Mod(..) => "module",
2904 ItemKind::ForeignMod(..) => "extern block",
2905 ItemKind::GlobalAsm(..) => "global asm item",
2906 ItemKind::TyAlias(..) => "type alias",
2907 ItemKind::Enum(..) => "enum",
2908 ItemKind::Struct(..) => "struct",
2909 ItemKind::Union(..) => "union",
2910 ItemKind::Trait(..) => "trait",
2911 ItemKind::TraitAlias(..) => "trait alias",
2912 ItemKind::MacCall(..) => "item macro invocation",
2913 ItemKind::MacroDef(..) => "macro definition",
2914 ItemKind::Impl { .. } => "implementation",
2918 pub fn generics(&self) -> Option<&Generics> {
2920 Self::Fn(box Fn { generics, .. })
2921 | Self::TyAlias(box TyAlias { generics, .. })
2922 | Self::Enum(_, generics)
2923 | Self::Struct(_, generics)
2924 | Self::Union(_, generics)
2925 | Self::Trait(box Trait { generics, .. })
2926 | Self::TraitAlias(generics, _)
2927 | Self::Impl(box Impl { generics, .. }) => Some(generics),
2933 /// Represents associated items.
2934 /// These include items in `impl` and `trait` definitions.
2935 pub type AssocItem = Item<AssocItemKind>;
2937 /// Represents associated item kinds.
2939 /// The term "provided" in the variants below refers to the item having a default
2940 /// definition / body. Meanwhile, a "required" item lacks a definition / body.
2941 /// In an implementation, all items must be provided.
2942 /// The `Option`s below denote the bodies, where `Some(_)`
2943 /// means "provided" and conversely `None` means "required".
2944 #[derive(Clone, Encodable, Decodable, Debug)]
2945 pub enum AssocItemKind {
2946 /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
2947 /// If `def` is parsed, then the constant is provided, and otherwise required.
2948 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2949 /// An associated function.
2951 /// An associated type.
2952 TyAlias(Box<TyAlias>),
2953 /// A macro expanding to associated items.
2954 MacCall(P<MacCall>),
2957 impl AssocItemKind {
2958 pub fn defaultness(&self) -> Defaultness {
2960 Self::Const(defaultness, ..)
2961 | Self::Fn(box Fn { defaultness, .. })
2962 | Self::TyAlias(box TyAlias { defaultness, .. }) => defaultness,
2963 Self::MacCall(..) => Defaultness::Final,
2968 impl From<AssocItemKind> for ItemKind {
2969 fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
2970 match assoc_item_kind {
2971 AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
2972 AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
2973 AssocItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
2974 AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
2979 impl TryFrom<ItemKind> for AssocItemKind {
2980 type Error = ItemKind;
2982 fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
2983 Ok(match item_kind {
2984 ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
2985 ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
2986 ItemKind::TyAlias(ty_alias_kind) => AssocItemKind::TyAlias(ty_alias_kind),
2987 ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
2988 _ => return Err(item_kind),
2993 /// An item in `extern` block.
2994 #[derive(Clone, Encodable, Decodable, Debug)]
2995 pub enum ForeignItemKind {
2996 /// A foreign static item (`static FOO: u8`).
2997 Static(P<Ty>, Mutability, Option<P<Expr>>),
2998 /// An foreign function.
3000 /// An foreign type.
3001 TyAlias(Box<TyAlias>),
3002 /// A macro expanding to foreign items.
3003 MacCall(P<MacCall>),
3006 impl From<ForeignItemKind> for ItemKind {
3007 fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
3008 match foreign_item_kind {
3009 ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
3010 ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
3011 ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
3012 ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
3017 impl TryFrom<ItemKind> for ForeignItemKind {
3018 type Error = ItemKind;
3020 fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
3021 Ok(match item_kind {
3022 ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
3023 ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
3024 ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
3025 ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
3026 _ => return Err(item_kind),
3031 pub type ForeignItem = Item<ForeignItemKind>;
3033 // Some nodes are used a lot. Make sure they don't unintentionally get bigger.
3034 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
3037 use rustc_data_structures::static_assert_size;
3038 // These are in alphabetical order, which is easy to maintain.
3039 static_assert_size!(AssocItem, 104);
3040 static_assert_size!(AssocItemKind, 32);
3041 static_assert_size!(Attribute, 32);
3042 static_assert_size!(Block, 48);
3043 static_assert_size!(Expr, 104);
3044 static_assert_size!(ExprKind, 72);
3045 static_assert_size!(Fn, 192);
3046 static_assert_size!(ForeignItem, 96);
3047 static_assert_size!(ForeignItemKind, 24);
3048 static_assert_size!(GenericBound, 88);
3049 static_assert_size!(Generics, 72);
3050 static_assert_size!(Impl, 200);
3051 static_assert_size!(Item, 184);
3052 static_assert_size!(ItemKind, 112);
3053 static_assert_size!(Lit, 48);
3054 static_assert_size!(LitKind, 24);
3055 static_assert_size!(Pat, 120);
3056 static_assert_size!(PatKind, 96);
3057 static_assert_size!(Path, 40);
3058 static_assert_size!(PathSegment, 24);
3059 static_assert_size!(Stmt, 32);
3060 static_assert_size!(StmtKind, 16);
3061 static_assert_size!(Ty, 96);
3062 static_assert_size!(TyKind, 72);