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, DelimToken, Token};
27 use crate::tokenstream::{DelimSpan, LazyTokenStream, TokenStream, TokenTree};
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::{self, Decoder, 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;
46 /// A "Label" is an identifier of some point in sources,
47 /// e.g. in the following code:
55 /// `'outer` is a label.
56 #[derive(Clone, Encodable, Decodable, Copy, HashStable_Generic)]
61 impl fmt::Debug for Label {
62 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
63 write!(f, "label({:?})", self.ident)
67 /// A "Lifetime" is an annotation of the scope in which variable
68 /// can be used, e.g. `'a` in `&'a i32`.
69 #[derive(Clone, Encodable, Decodable, Copy)]
75 impl fmt::Debug for Lifetime {
76 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
77 write!(f, "lifetime({}: {})", self.id, self)
81 impl fmt::Display for Lifetime {
82 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
83 write!(f, "{}", self.ident.name)
87 /// A "Path" is essentially Rust's notion of a name.
89 /// It's represented as a sequence of identifiers,
90 /// along with a bunch of supporting information.
92 /// E.g., `std::cmp::PartialEq`.
93 #[derive(Clone, Encodable, Decodable, Debug)]
96 /// The segments in the path: the things separated by `::`.
97 /// Global paths begin with `kw::PathRoot`.
98 pub segments: Vec<PathSegment>,
99 pub tokens: Option<LazyTokenStream>,
102 impl PartialEq<Symbol> for Path {
103 fn eq(&self, symbol: &Symbol) -> bool {
104 self.segments.len() == 1 && { self.segments[0].ident.name == *symbol }
108 impl<CTX> HashStable<CTX> for Path {
109 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
110 self.segments.len().hash_stable(hcx, hasher);
111 for segment in &self.segments {
112 segment.ident.name.hash_stable(hcx, hasher);
118 // Convert a span and an identifier to the corresponding
120 pub fn from_ident(ident: Ident) -> Path {
121 Path { segments: vec![PathSegment::from_ident(ident)], span: ident.span, tokens: None }
124 pub fn is_global(&self) -> bool {
125 !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
129 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
131 /// E.g., `std`, `String` or `Box<T>`.
132 #[derive(Clone, Encodable, Decodable, Debug)]
133 pub struct PathSegment {
134 /// The identifier portion of this path segment.
139 /// Type/lifetime parameters attached to this path. They come in
140 /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
141 /// `None` means that no parameter list is supplied (`Path`),
142 /// `Some` means that parameter list is supplied (`Path<X, Y>`)
143 /// but it can be empty (`Path<>`).
144 /// `P` is used as a size optimization for the common case with no parameters.
145 pub args: Option<P<GenericArgs>>,
149 pub fn from_ident(ident: Ident) -> Self {
150 PathSegment { ident, id: DUMMY_NODE_ID, args: None }
153 pub fn path_root(span: Span) -> Self {
154 PathSegment::from_ident(Ident::new(kw::PathRoot, span))
157 pub fn span(&self) -> Span {
159 Some(args) => self.ident.span.to(args.span()),
160 None => self.ident.span,
165 /// The arguments of a path segment.
167 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
168 #[derive(Clone, Encodable, Decodable, Debug)]
169 pub enum GenericArgs {
170 /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
171 AngleBracketed(AngleBracketedArgs),
172 /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
173 Parenthesized(ParenthesizedArgs),
177 pub fn is_angle_bracketed(&self) -> bool {
178 matches!(self, AngleBracketed(..))
181 pub fn span(&self) -> Span {
183 AngleBracketed(ref data) => data.span,
184 Parenthesized(ref data) => data.span,
189 /// Concrete argument in the sequence of generic args.
190 #[derive(Clone, Encodable, Decodable, Debug)]
191 pub enum GenericArg {
192 /// `'a` in `Foo<'a>`
194 /// `Bar` in `Foo<Bar>`
201 pub fn span(&self) -> Span {
203 GenericArg::Lifetime(lt) => lt.ident.span,
204 GenericArg::Type(ty) => ty.span,
205 GenericArg::Const(ct) => ct.value.span,
210 /// A path like `Foo<'a, T>`.
211 #[derive(Clone, Encodable, Decodable, Debug, Default)]
212 pub struct AngleBracketedArgs {
213 /// The overall span.
215 /// The comma separated parts in the `<...>`.
216 pub args: Vec<AngleBracketedArg>,
219 /// Either an argument for a parameter e.g., `'a`, `Vec<u8>`, `0`,
220 /// or a constraint on an associated item, e.g., `Item = String` or `Item: Bound`.
221 #[derive(Clone, Encodable, Decodable, Debug)]
222 pub enum AngleBracketedArg {
223 /// Argument for a generic parameter.
225 /// Constraint for an associated item.
226 Constraint(AssocTyConstraint),
229 impl AngleBracketedArg {
230 pub fn span(&self) -> Span {
232 AngleBracketedArg::Arg(arg) => arg.span(),
233 AngleBracketedArg::Constraint(constraint) => constraint.span,
238 impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
239 fn into(self) -> Option<P<GenericArgs>> {
240 Some(P(GenericArgs::AngleBracketed(self)))
244 impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
245 fn into(self) -> Option<P<GenericArgs>> {
246 Some(P(GenericArgs::Parenthesized(self)))
250 /// A path like `Foo(A, B) -> C`.
251 #[derive(Clone, Encodable, Decodable, Debug)]
252 pub struct ParenthesizedArgs {
260 pub inputs: Vec<P<Ty>>,
266 pub inputs_span: Span,
272 impl ParenthesizedArgs {
273 pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
278 .map(|input| AngleBracketedArg::Arg(GenericArg::Type(input)))
280 AngleBracketedArgs { span: self.span, args }
284 pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
286 /// A modifier on a bound, e.g., `?Sized` or `?const Trait`.
288 /// Negative bounds should also be handled here.
289 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
290 pub enum TraitBoundModifier {
302 // This parses but will be rejected during AST validation.
306 /// The AST represents all type param bounds as types.
307 /// `typeck::collect::compute_bounds` matches these against
308 /// the "special" built-in traits (see `middle::lang_items`) and
309 /// detects `Copy`, `Send` and `Sync`.
310 #[derive(Clone, Encodable, Decodable, Debug)]
311 pub enum GenericBound {
312 Trait(PolyTraitRef, TraitBoundModifier),
317 pub fn span(&self) -> Span {
319 GenericBound::Trait(ref t, ..) => t.span,
320 GenericBound::Outlives(ref l) => l.ident.span,
325 pub type GenericBounds = Vec<GenericBound>;
327 /// Specifies the enforced ordering for generic parameters. In the future,
328 /// if we wanted to relax this order, we could override `PartialEq` and
329 /// `PartialOrd`, to allow the kinds to be unordered.
330 #[derive(Hash, Clone, Copy)]
331 pub enum ParamKindOrd {
334 // `unordered` is only `true` if `sess.has_features().const_generics`
335 // is active. Specifically, if it's only `min_const_generics`, it will still require
336 // ordering consts after types.
337 Const { unordered: bool },
340 impl Ord for ParamKindOrd {
341 fn cmp(&self, other: &Self) -> Ordering {
343 let to_int = |v| match v {
345 Type | Const { unordered: true } => 1,
346 // technically both consts should be ordered equally,
347 // but only one is ever encountered at a time, so this is
349 Const { unordered: false } => 2,
352 to_int(*self).cmp(&to_int(*other))
355 impl PartialOrd for ParamKindOrd {
356 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
357 Some(self.cmp(other))
360 impl PartialEq for ParamKindOrd {
361 fn eq(&self, other: &Self) -> bool {
362 self.cmp(other) == Ordering::Equal
365 impl Eq for ParamKindOrd {}
367 impl fmt::Display for ParamKindOrd {
368 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
370 ParamKindOrd::Lifetime => "lifetime".fmt(f),
371 ParamKindOrd::Type => "type".fmt(f),
372 ParamKindOrd::Const { .. } => "const".fmt(f),
377 #[derive(Clone, Encodable, Decodable, Debug)]
378 pub enum GenericParamKind {
379 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
382 default: Option<P<Ty>>,
386 /// Span of the `const` keyword.
388 /// Optional default value for the const generic param
389 default: Option<AnonConst>,
393 #[derive(Clone, Encodable, Decodable, Debug)]
394 pub struct GenericParam {
398 pub bounds: GenericBounds,
399 pub is_placeholder: bool,
400 pub kind: GenericParamKind,
403 /// Represents lifetime, type and const parameters attached to a declaration of
404 /// a function, enum, trait, etc.
405 #[derive(Clone, Encodable, Decodable, Debug)]
406 pub struct Generics {
407 pub params: Vec<GenericParam>,
408 pub where_clause: WhereClause,
412 impl Default for Generics {
413 /// Creates an instance of `Generics`.
414 fn default() -> Generics {
417 where_clause: WhereClause {
418 has_where_token: false,
419 predicates: Vec::new(),
427 /// A where-clause in a definition.
428 #[derive(Clone, Encodable, Decodable, Debug)]
429 pub struct WhereClause {
430 /// `true` if we ate a `where` token: this can happen
431 /// if we parsed no predicates (e.g. `struct Foo where {}`).
432 /// This allows us to accurately pretty-print
433 /// in `nt_to_tokenstream`
434 pub has_where_token: bool,
435 pub predicates: Vec<WherePredicate>,
439 /// A single predicate in a where-clause.
440 #[derive(Clone, Encodable, Decodable, Debug)]
441 pub enum WherePredicate {
442 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
443 BoundPredicate(WhereBoundPredicate),
444 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
445 RegionPredicate(WhereRegionPredicate),
446 /// An equality predicate (unsupported).
447 EqPredicate(WhereEqPredicate),
450 impl WherePredicate {
451 pub fn span(&self) -> Span {
453 WherePredicate::BoundPredicate(p) => p.span,
454 WherePredicate::RegionPredicate(p) => p.span,
455 WherePredicate::EqPredicate(p) => p.span,
462 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
463 #[derive(Clone, Encodable, Decodable, Debug)]
464 pub struct WhereBoundPredicate {
466 /// Any generics from a `for` binding.
467 pub bound_generic_params: Vec<GenericParam>,
468 /// The type being bounded.
469 pub bounded_ty: P<Ty>,
470 /// Trait and lifetime bounds (`Clone + Send + 'static`).
471 pub bounds: GenericBounds,
474 /// A lifetime predicate.
476 /// E.g., `'a: 'b + 'c`.
477 #[derive(Clone, Encodable, Decodable, Debug)]
478 pub struct WhereRegionPredicate {
480 pub lifetime: Lifetime,
481 pub bounds: GenericBounds,
484 /// An equality predicate (unsupported).
487 #[derive(Clone, Encodable, Decodable, Debug)]
488 pub struct WhereEqPredicate {
495 #[derive(Clone, Encodable, Decodable, Debug)]
497 pub attrs: Vec<Attribute>,
498 pub items: Vec<P<Item>>,
500 /// The order of items in the HIR is unrelated to the order of
501 /// items in the AST. However, we generate proc macro harnesses
502 /// based on the AST order, and later refer to these harnesses
503 /// from the HIR. This field keeps track of the order in which
504 /// we generated proc macros harnesses, so that we can map
505 /// HIR proc macros items back to their harness items.
506 pub proc_macros: Vec<NodeId>,
509 /// Possible values inside of compile-time attribute lists.
511 /// E.g., the '..' in `#[name(..)]`.
512 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
513 pub enum NestedMetaItem {
514 /// A full MetaItem, for recursive meta items.
518 /// E.g., `"foo"`, `64`, `true`.
522 /// A spanned compile-time attribute item.
524 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
525 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
526 pub struct MetaItem {
528 pub kind: MetaItemKind,
532 /// A compile-time attribute item.
534 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
535 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
536 pub enum MetaItemKind {
539 /// E.g., `test` as in `#[test]`.
543 /// E.g., `derive(..)` as in `#[derive(..)]`.
544 List(Vec<NestedMetaItem>),
545 /// Name value meta item.
547 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
551 /// A block (`{ .. }`).
553 /// E.g., `{ .. }` as in `fn foo() { .. }`.
554 #[derive(Clone, Encodable, Decodable, Debug)]
556 /// The statements in the block.
557 pub stmts: Vec<Stmt>,
559 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
560 pub rules: BlockCheckMode,
562 pub tokens: Option<LazyTokenStream>,
567 /// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
568 #[derive(Clone, Encodable, Decodable, Debug)]
573 pub tokens: Option<LazyTokenStream>,
577 /// Attempt reparsing the pattern as a type.
578 /// This is intended for use by diagnostics.
579 pub fn to_ty(&self) -> Option<P<Ty>> {
580 let kind = match &self.kind {
581 // In a type expression `_` is an inference variable.
582 PatKind::Wild => TyKind::Infer,
583 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
584 PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
585 TyKind::Path(None, Path::from_ident(*ident))
587 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
588 PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
589 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
590 PatKind::Ref(pat, mutbl) => {
591 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
593 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
594 // when `P` can be reparsed as a type `T`.
595 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
596 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
597 // assuming `T0` to `Tn` are all syntactically valid as types.
598 PatKind::Tuple(pats) => {
599 let mut tys = Vec::with_capacity(pats.len());
600 // FIXME(#48994) - could just be collected into an Option<Vec>
602 tys.push(pat.to_ty()?);
609 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
612 /// Walk top-down and call `it` in each place where a pattern occurs
613 /// starting with the root pattern `walk` is called on. If `it` returns
614 /// false then we will descend no further but siblings will be processed.
615 pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
621 // Walk into the pattern associated with `Ident` (if any).
622 PatKind::Ident(_, _, Some(p)) => p.walk(it),
624 // Walk into each field of struct.
625 PatKind::Struct(_, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
627 // Sequence of patterns.
628 PatKind::TupleStruct(_, s) | PatKind::Tuple(s) | PatKind::Slice(s) | PatKind::Or(s) => {
629 s.iter().for_each(|p| p.walk(it))
632 // Trivial wrappers over inner patterns.
633 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
635 // These patterns do not contain subpatterns, skip.
642 | PatKind::MacCall(_) => {}
646 /// Is this a `..` pattern?
647 pub fn is_rest(&self) -> bool {
648 matches!(self.kind, PatKind::Rest)
652 /// A single field in a struct pattern.
654 /// Patterns like the fields of `Foo { x, ref y, ref mut z }`
655 /// are treated the same as `x: x, y: ref y, z: ref mut z`,
656 /// except when `is_shorthand` is true.
657 #[derive(Clone, Encodable, Decodable, Debug)]
658 pub struct PatField {
659 /// The identifier for the field.
661 /// The pattern the field is destructured to.
663 pub is_shorthand: bool,
667 pub is_placeholder: bool,
670 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
671 pub enum BindingMode {
676 #[derive(Clone, Encodable, Decodable, Debug)]
678 Included(RangeSyntax),
682 #[derive(Clone, Encodable, Decodable, Debug)]
683 pub enum RangeSyntax {
690 #[derive(Clone, Encodable, Decodable, Debug)]
692 /// Represents a wildcard pattern (`_`).
695 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
696 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
697 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
698 /// during name resolution.
699 Ident(BindingMode, Ident, Option<P<Pat>>),
701 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
702 /// The `bool` is `true` in the presence of a `..`.
703 Struct(Path, Vec<PatField>, /* recovered */ bool),
705 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
706 TupleStruct(Path, Vec<P<Pat>>),
708 /// An or-pattern `A | B | C`.
709 /// Invariant: `pats.len() >= 2`.
712 /// A possibly qualified path pattern.
713 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
714 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
715 /// only legally refer to associated constants.
716 Path(Option<QSelf>, Path),
718 /// A tuple pattern (`(a, b)`).
724 /// A reference pattern (e.g., `&mut (a, b)`).
725 Ref(P<Pat>, Mutability),
730 /// A range pattern (e.g., `1...2`, `1..=2` or `1..2`).
731 Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
733 /// A slice pattern `[a, b, c]`.
736 /// A rest pattern `..`.
738 /// Syntactically it is valid anywhere.
740 /// Semantically however, it only has meaning immediately inside:
741 /// - a slice pattern: `[a, .., b]`,
742 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
743 /// - a tuple pattern: `(a, .., b)`,
744 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
746 /// In all of these cases, an additional restriction applies,
747 /// only one rest pattern may occur in the pattern sequences.
750 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
753 /// A macro pattern; pre-expansion.
757 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
758 #[derive(HashStable_Generic, Encodable, Decodable)]
759 pub enum Mutability {
765 /// Returns `MutMutable` only if both `self` and `other` are mutable.
766 pub fn and(self, other: Self) -> Self {
768 Mutability::Mut => other,
769 Mutability::Not => Mutability::Not,
773 pub fn invert(self) -> Self {
775 Mutability::Mut => Mutability::Not,
776 Mutability::Not => Mutability::Mut,
780 pub fn prefix_str(&self) -> &'static str {
782 Mutability::Mut => "mut ",
783 Mutability::Not => "",
788 /// The kind of borrow in an `AddrOf` expression,
789 /// e.g., `&place` or `&raw const place`.
790 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
791 #[derive(Encodable, Decodable, HashStable_Generic)]
792 pub enum BorrowKind {
793 /// A normal borrow, `&$expr` or `&mut $expr`.
794 /// The resulting type is either `&'a T` or `&'a mut T`
795 /// where `T = typeof($expr)` and `'a` is some lifetime.
797 /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
798 /// The resulting type is either `*const T` or `*mut T`
799 /// where `T = typeof($expr)`.
803 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
805 /// The `+` operator (addition)
807 /// The `-` operator (subtraction)
809 /// The `*` operator (multiplication)
811 /// The `/` operator (division)
813 /// The `%` operator (modulus)
815 /// The `&&` operator (logical and)
817 /// The `||` operator (logical or)
819 /// The `^` operator (bitwise xor)
821 /// The `&` operator (bitwise and)
823 /// The `|` operator (bitwise or)
825 /// The `<<` operator (shift left)
827 /// The `>>` operator (shift right)
829 /// The `==` operator (equality)
831 /// The `<` operator (less than)
833 /// The `<=` operator (less than or equal to)
835 /// The `!=` operator (not equal to)
837 /// The `>=` operator (greater than or equal to)
839 /// The `>` operator (greater than)
844 pub fn to_string(&self) -> &'static str {
867 pub fn lazy(&self) -> bool {
868 matches!(self, BinOpKind::And | BinOpKind::Or)
871 pub fn is_comparison(&self) -> bool {
873 // Note for developers: please keep this as is;
874 // we want compilation to fail if another variant is added.
876 Eq | Lt | Le | Ne | Gt | Ge => true,
877 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
882 pub type BinOp = Spanned<BinOpKind>;
886 /// Note that `&data` is not an operator, it's an `AddrOf` expression.
887 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
889 /// The `*` operator for dereferencing
891 /// The `!` operator for logical inversion
893 /// The `-` operator for negation
898 pub fn to_string(op: UnOp) -> &'static str {
908 #[derive(Clone, Encodable, Decodable, Debug)]
916 pub fn tokens(&self) -> Option<&LazyTokenStream> {
918 StmtKind::Local(ref local) => local.tokens.as_ref(),
919 StmtKind::Item(ref item) => item.tokens.as_ref(),
920 StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => expr.tokens.as_ref(),
921 StmtKind::Empty => None,
922 StmtKind::MacCall(ref mac) => mac.tokens.as_ref(),
926 pub fn has_trailing_semicolon(&self) -> bool {
928 StmtKind::Semi(_) => true,
929 StmtKind::MacCall(mac) => matches!(mac.style, MacStmtStyle::Semicolon),
934 /// Converts a parsed `Stmt` to a `Stmt` with
935 /// a trailing semicolon.
937 /// This only modifies the parsed AST struct, not the attached
938 /// `LazyTokenStream`. The parser is responsible for calling
939 /// `CreateTokenStream::add_trailing_semi` when there is actually
940 /// a semicolon in the tokenstream.
941 pub fn add_trailing_semicolon(mut self) -> Self {
942 self.kind = match self.kind {
943 StmtKind::Expr(expr) => StmtKind::Semi(expr),
944 StmtKind::MacCall(mac) => {
945 StmtKind::MacCall(mac.map(|MacCallStmt { mac, style: _, attrs, tokens }| {
946 MacCallStmt { mac, style: MacStmtStyle::Semicolon, attrs, tokens }
955 pub fn is_item(&self) -> bool {
956 matches!(self.kind, StmtKind::Item(_))
959 pub fn is_expr(&self) -> bool {
960 matches!(self.kind, StmtKind::Expr(_))
964 #[derive(Clone, Encodable, Decodable, Debug)]
966 /// A local (let) binding.
968 /// An item definition.
970 /// Expr without trailing semi-colon.
972 /// Expr with a trailing semi-colon.
974 /// Just a trailing semi-colon.
977 MacCall(P<MacCallStmt>),
980 #[derive(Clone, Encodable, Decodable, Debug)]
981 pub struct MacCallStmt {
983 pub style: MacStmtStyle,
985 pub tokens: Option<LazyTokenStream>,
988 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
989 pub enum MacStmtStyle {
990 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
991 /// `foo!(...);`, `foo![...];`).
993 /// The macro statement had braces (e.g., `foo! { ... }`).
995 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
996 /// `foo!(...)`). All of these will end up being converted into macro
1001 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
1002 #[derive(Clone, Encodable, Decodable, Debug)]
1006 pub ty: Option<P<Ty>>,
1007 /// Initializer expression to set the value, if any.
1008 pub init: Option<P<Expr>>,
1011 pub tokens: Option<LazyTokenStream>,
1014 /// An arm of a 'match'.
1016 /// E.g., `0..=10 => { println!("match!") }` as in
1020 /// 0..=10 => { println!("match!") },
1021 /// _ => { println!("no match!") },
1024 #[derive(Clone, Encodable, Decodable, Debug)]
1026 pub attrs: Vec<Attribute>,
1027 /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
1029 /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
1030 pub guard: Option<P<Expr>>,
1035 pub is_placeholder: bool,
1038 /// A single field in a struct expression, e.g. `x: value` and `y` in `Foo { x: value, y }`.
1039 #[derive(Clone, Encodable, Decodable, Debug)]
1040 pub struct ExprField {
1046 pub is_shorthand: bool,
1047 pub is_placeholder: bool,
1050 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1051 pub enum BlockCheckMode {
1053 Unsafe(UnsafeSource),
1056 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1057 pub enum UnsafeSource {
1062 /// A constant (expression) that's not an item or associated item,
1063 /// but needs its own `DefId` for type-checking, const-eval, etc.
1064 /// These are usually found nested inside types (e.g., array lengths)
1065 /// or expressions (e.g., repeat counts), and also used to define
1066 /// explicit discriminant values for enum variants.
1067 #[derive(Clone, Encodable, Decodable, Debug)]
1068 pub struct AnonConst {
1074 #[derive(Clone, Encodable, Decodable, Debug)]
1080 pub tokens: Option<LazyTokenStream>,
1083 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
1084 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
1085 rustc_data_structures::static_assert_size!(Expr, 104);
1088 /// Returns `true` if this expression would be valid somewhere that expects a value;
1089 /// for example, an `if` condition.
1090 pub fn returns(&self) -> bool {
1091 if let ExprKind::Block(ref block, _) = self.kind {
1092 match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
1094 Some(StmtKind::Expr(_)) => true,
1095 // Last statement is an explicit return?
1096 Some(StmtKind::Semi(expr)) => matches!(expr.kind, ExprKind::Ret(_)),
1097 // This is a block that doesn't end in either an implicit or explicit return.
1101 // This is not a block, it is a value.
1106 /// Is this expr either `N`, or `{ N }`.
1108 /// If this is not the case, name resolution does not resolve `N` when using
1109 /// `min_const_generics` as more complex expressions are not supported.
1110 pub fn is_potential_trivial_const_param(&self) -> bool {
1111 let this = if let ExprKind::Block(ref block, None) = self.kind {
1112 if block.stmts.len() == 1 {
1113 if let StmtKind::Expr(ref expr) = block.stmts[0].kind { expr } else { self }
1121 if let ExprKind::Path(None, ref path) = this.kind {
1122 if path.segments.len() == 1 && path.segments[0].args.is_none() {
1130 pub fn to_bound(&self) -> Option<GenericBound> {
1132 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1133 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1134 TraitBoundModifier::None,
1140 pub fn peel_parens(&self) -> &Expr {
1141 let mut expr = self;
1142 while let ExprKind::Paren(inner) = &expr.kind {
1148 /// Attempts to reparse as `Ty` (for diagnostic purposes).
1149 pub fn to_ty(&self) -> Option<P<Ty>> {
1150 let kind = match &self.kind {
1151 // Trivial conversions.
1152 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1153 ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
1155 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1157 ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
1158 expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
1161 ExprKind::Repeat(expr, expr_len) => {
1162 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1165 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1167 ExprKind::Tup(exprs) => {
1168 let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
1172 // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
1173 // then type of result is trait object.
1174 // Otherwise we don't assume the result type.
1175 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1176 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1177 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1183 // This expression doesn't look like a type syntactically.
1187 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
1190 pub fn precedence(&self) -> ExprPrecedence {
1192 ExprKind::Box(_) => ExprPrecedence::Box,
1193 ExprKind::Array(_) => ExprPrecedence::Array,
1194 ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
1195 ExprKind::Call(..) => ExprPrecedence::Call,
1196 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1197 ExprKind::Tup(_) => ExprPrecedence::Tup,
1198 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1199 ExprKind::Unary(..) => ExprPrecedence::Unary,
1200 ExprKind::Lit(_) => ExprPrecedence::Lit,
1201 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1202 ExprKind::Let(..) => ExprPrecedence::Let,
1203 ExprKind::If(..) => ExprPrecedence::If,
1204 ExprKind::While(..) => ExprPrecedence::While,
1205 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1206 ExprKind::Loop(..) => ExprPrecedence::Loop,
1207 ExprKind::Match(..) => ExprPrecedence::Match,
1208 ExprKind::Closure(..) => ExprPrecedence::Closure,
1209 ExprKind::Block(..) => ExprPrecedence::Block,
1210 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1211 ExprKind::Async(..) => ExprPrecedence::Async,
1212 ExprKind::Await(..) => ExprPrecedence::Await,
1213 ExprKind::Assign(..) => ExprPrecedence::Assign,
1214 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1215 ExprKind::Field(..) => ExprPrecedence::Field,
1216 ExprKind::Index(..) => ExprPrecedence::Index,
1217 ExprKind::Range(..) => ExprPrecedence::Range,
1218 ExprKind::Underscore => ExprPrecedence::Path,
1219 ExprKind::Path(..) => ExprPrecedence::Path,
1220 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1221 ExprKind::Break(..) => ExprPrecedence::Break,
1222 ExprKind::Continue(..) => ExprPrecedence::Continue,
1223 ExprKind::Ret(..) => ExprPrecedence::Ret,
1224 ExprKind::InlineAsm(..) | ExprKind::LlvmInlineAsm(..) => ExprPrecedence::InlineAsm,
1225 ExprKind::MacCall(..) => ExprPrecedence::Mac,
1226 ExprKind::Struct(..) => ExprPrecedence::Struct,
1227 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1228 ExprKind::Paren(..) => ExprPrecedence::Paren,
1229 ExprKind::Try(..) => ExprPrecedence::Try,
1230 ExprKind::Yield(..) => ExprPrecedence::Yield,
1231 ExprKind::Err => ExprPrecedence::Err,
1236 /// Limit types of a range (inclusive or exclusive)
1237 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
1238 pub enum RangeLimits {
1239 /// Inclusive at the beginning, exclusive at the end
1241 /// Inclusive at the beginning and end
1245 #[derive(Clone, Encodable, Decodable, Debug)]
1246 pub enum StructRest {
1251 /// No trailing `..` or expression.
1255 #[derive(Clone, Encodable, Decodable, Debug)]
1256 pub struct StructExpr {
1258 pub fields: Vec<ExprField>,
1259 pub rest: StructRest,
1262 #[derive(Clone, Encodable, Decodable, Debug)]
1264 /// A `box x` expression.
1266 /// An array (`[a, b, c, d]`)
1267 Array(Vec<P<Expr>>),
1268 /// Allow anonymous constants from an inline `const` block
1269 ConstBlock(AnonConst),
1272 /// The first field resolves to the function itself,
1273 /// and the second field is the list of arguments.
1274 /// This also represents calling the constructor of
1275 /// tuple-like ADTs such as tuple structs and enum variants.
1276 Call(P<Expr>, Vec<P<Expr>>),
1277 /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1279 /// The `PathSegment` represents the method name and its generic arguments
1280 /// (within the angle brackets).
1281 /// The first element of the vector of an `Expr` is the expression that evaluates
1282 /// to the object on which the method is being called on (the receiver),
1283 /// and the remaining elements are the rest of the arguments.
1284 /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1285 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
1286 /// This `Span` is the span of the function, without the dot and receiver
1287 /// (e.g. `foo(a, b)` in `x.foo(a, b)`
1288 MethodCall(PathSegment, Vec<P<Expr>>, Span),
1289 /// A tuple (e.g., `(a, b, c, d)`).
1291 /// A binary operation (e.g., `a + b`, `a * b`).
1292 Binary(BinOp, P<Expr>, P<Expr>),
1293 /// A unary operation (e.g., `!x`, `*x`).
1294 Unary(UnOp, P<Expr>),
1295 /// A literal (e.g., `1`, `"foo"`).
1297 /// A cast (e.g., `foo as f64`).
1298 Cast(P<Expr>, P<Ty>),
1299 /// A type ascription (e.g., `42: usize`).
1300 Type(P<Expr>, P<Ty>),
1301 /// A `let pat = expr` expression that is only semantically allowed in the condition
1302 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1303 Let(P<Pat>, P<Expr>),
1304 /// An `if` block, with an optional `else` block.
1306 /// `if expr { block } else { expr }`
1307 If(P<Expr>, P<Block>, Option<P<Expr>>),
1308 /// A while loop, with an optional label.
1310 /// `'label: while expr { block }`
1311 While(P<Expr>, P<Block>, Option<Label>),
1312 /// A `for` loop, with an optional label.
1314 /// `'label: for pat in expr { block }`
1316 /// This is desugared to a combination of `loop` and `match` expressions.
1317 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1318 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1320 /// `'label: loop { block }`
1321 Loop(P<Block>, Option<Label>),
1322 /// A `match` block.
1323 Match(P<Expr>, Vec<Arm>),
1324 /// A closure (e.g., `move |a, b, c| a + b + c`).
1326 /// The final span is the span of the argument block `|...|`.
1327 Closure(CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
1328 /// A block (`'label: { ... }`).
1329 Block(P<Block>, Option<Label>),
1330 /// An async block (`async move { ... }`).
1332 /// The `NodeId` is the `NodeId` for the closure that results from
1333 /// desugaring an async block, just like the NodeId field in the
1334 /// `Async::Yes` variant. This is necessary in order to create a def for the
1335 /// closure which can be used as a parent of any child defs. Defs
1336 /// created during lowering cannot be made the parent of any other
1337 /// preexisting defs.
1338 Async(CaptureBy, NodeId, P<Block>),
1339 /// An await expression (`my_future.await`).
1342 /// A try block (`try { ... }`).
1345 /// An assignment (`a = foo()`).
1346 /// The `Span` argument is the span of the `=` token.
1347 Assign(P<Expr>, P<Expr>, Span),
1348 /// An assignment with an operator.
1351 AssignOp(BinOp, P<Expr>, P<Expr>),
1352 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1353 Field(P<Expr>, Ident),
1354 /// An indexing operation (e.g., `foo[2]`).
1355 Index(P<Expr>, P<Expr>),
1356 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assingment).
1357 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1358 /// An underscore, used in destructuring assignment to ignore a value.
1361 /// Variable reference, possibly containing `::` and/or type
1362 /// parameters (e.g., `foo::bar::<baz>`).
1364 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1365 Path(Option<QSelf>, Path),
1367 /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
1368 AddrOf(BorrowKind, Mutability, P<Expr>),
1369 /// A `break`, with an optional label to break, and an optional expression.
1370 Break(Option<Label>, Option<P<Expr>>),
1371 /// A `continue`, with an optional label.
1372 Continue(Option<Label>),
1373 /// A `return`, with an optional value to be returned.
1374 Ret(Option<P<Expr>>),
1376 /// Output of the `asm!()` macro.
1377 InlineAsm(P<InlineAsm>),
1378 /// Output of the `llvm_asm!()` macro.
1379 LlvmInlineAsm(P<LlvmInlineAsm>),
1381 /// A macro invocation; pre-expansion.
1384 /// A struct literal expression.
1386 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
1387 Struct(P<StructExpr>),
1389 /// An array literal constructed from one repeated element.
1391 /// E.g., `[1; 5]`. The expression is the element to be
1392 /// repeated; the constant is the number of times to repeat it.
1393 Repeat(P<Expr>, AnonConst),
1395 /// No-op: used solely so we can pretty-print faithfully.
1398 /// A try expression (`expr?`).
1401 /// A `yield`, with an optional value to be yielded.
1402 Yield(Option<P<Expr>>),
1404 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1408 /// The explicit `Self` type in a "qualified path". The actual
1409 /// path, including the trait and the associated item, is stored
1410 /// separately. `position` represents the index of the associated
1411 /// item qualified with this `Self` type.
1413 /// ```ignore (only-for-syntax-highlight)
1414 /// <Vec<T> as a::b::Trait>::AssociatedItem
1415 /// ^~~~~ ~~~~~~~~~~~~~~^
1418 /// <Vec<T>>::AssociatedItem
1422 #[derive(Clone, Encodable, Decodable, Debug)]
1426 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1427 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1428 /// 0`, this is an empty span.
1429 pub path_span: Span,
1430 pub position: usize,
1433 /// A capture clause used in closures and `async` blocks.
1434 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1435 pub enum CaptureBy {
1436 /// `move |x| y + x`.
1438 /// `move` keyword was not specified.
1442 /// The movability of a generator / closure literal:
1443 /// whether a generator contains self-references, causing it to be `!Unpin`.
1444 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
1445 #[derive(HashStable_Generic)]
1446 pub enum Movability {
1447 /// May contain self-references, `!Unpin`.
1449 /// Must not contain self-references, `Unpin`.
1453 /// Represents a macro invocation. The `path` indicates which macro
1454 /// is being invoked, and the `args` are arguments passed to it.
1455 #[derive(Clone, Encodable, Decodable, Debug)]
1456 pub struct MacCall {
1458 pub args: P<MacArgs>,
1459 pub prior_type_ascription: Option<(Span, bool)>,
1463 pub fn span(&self) -> Span {
1464 self.path.span.to(self.args.span().unwrap_or(self.path.span))
1468 /// Arguments passed to an attribute or a function-like macro.
1469 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1471 /// No arguments - `#[attr]`.
1473 /// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
1474 Delimited(DelimSpan, MacDelimiter, TokenStream),
1475 /// Arguments of a key-value attribute - `#[attr = "value"]`.
1477 /// Span of the `=` token.
1479 /// "value" as a nonterminal token.
1485 pub fn delim(&self) -> DelimToken {
1487 MacArgs::Delimited(_, delim, _) => delim.to_token(),
1488 MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
1492 pub fn span(&self) -> Option<Span> {
1494 MacArgs::Empty => None,
1495 MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
1496 MacArgs::Eq(eq_span, token) => Some(eq_span.to(token.span)),
1500 /// Tokens inside the delimiters or after `=`.
1501 /// Proc macros see these tokens, for example.
1502 pub fn inner_tokens(&self) -> TokenStream {
1504 MacArgs::Empty => TokenStream::default(),
1505 MacArgs::Delimited(.., tokens) => tokens.clone(),
1506 MacArgs::Eq(.., token) => TokenTree::Token(token.clone()).into(),
1510 /// Whether a macro with these arguments needs a semicolon
1511 /// when used as a standalone item or statement.
1512 pub fn need_semicolon(&self) -> bool {
1513 !matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
1517 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
1518 pub enum MacDelimiter {
1525 pub fn to_token(self) -> DelimToken {
1527 MacDelimiter::Parenthesis => DelimToken::Paren,
1528 MacDelimiter::Bracket => DelimToken::Bracket,
1529 MacDelimiter::Brace => DelimToken::Brace,
1533 pub fn from_token(delim: DelimToken) -> Option<MacDelimiter> {
1535 token::Paren => Some(MacDelimiter::Parenthesis),
1536 token::Bracket => Some(MacDelimiter::Bracket),
1537 token::Brace => Some(MacDelimiter::Brace),
1538 token::NoDelim => None,
1543 /// Represents a macro definition.
1544 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1545 pub struct MacroDef {
1546 pub body: P<MacArgs>,
1547 /// `true` if macro was defined with `macro_rules`.
1548 pub macro_rules: bool,
1551 #[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
1552 #[derive(HashStable_Generic)]
1554 /// A regular string, like `"foo"`.
1556 /// A raw string, like `r##"foo"##`.
1558 /// The value is the number of `#` symbols used.
1563 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1565 /// The original literal token as written in source code.
1566 pub token: token::Lit,
1567 /// The "semantic" representation of the literal lowered from the original tokens.
1568 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1569 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1574 /// Same as `Lit`, but restricted to string literals.
1575 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1577 /// The original literal token as written in source code.
1578 pub style: StrStyle,
1580 pub suffix: Option<Symbol>,
1582 /// The unescaped "semantic" representation of the literal lowered from the original token.
1583 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1584 pub symbol_unescaped: Symbol,
1588 pub fn as_lit(&self) -> Lit {
1589 let token_kind = match self.style {
1590 StrStyle::Cooked => token::Str,
1591 StrStyle::Raw(n) => token::StrRaw(n),
1594 token: token::Lit::new(token_kind, self.symbol, self.suffix),
1596 kind: LitKind::Str(self.symbol_unescaped, self.style),
1601 /// Type of the integer literal based on provided suffix.
1602 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1603 #[derive(HashStable_Generic)]
1604 pub enum LitIntType {
1613 /// Type of the float literal based on provided suffix.
1614 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1615 #[derive(HashStable_Generic)]
1616 pub enum LitFloatType {
1617 /// A float literal with a suffix (`1f32` or `1E10f32`).
1619 /// A float literal without a suffix (`1.0 or 1.0E10`).
1625 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
1626 #[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
1628 /// A string literal (`"foo"`).
1629 Str(Symbol, StrStyle),
1630 /// A byte string (`b"foo"`).
1632 /// A byte char (`b'f'`).
1634 /// A character literal (`'a'`).
1636 /// An integer literal (`1`).
1637 Int(u128, LitIntType),
1638 /// A float literal (`1f64` or `1E10f64`).
1639 Float(Symbol, LitFloatType),
1640 /// A boolean literal.
1642 /// Placeholder for a literal that wasn't well-formed in some way.
1647 /// Returns `true` if this literal is a string.
1648 pub fn is_str(&self) -> bool {
1649 matches!(self, LitKind::Str(..))
1652 /// Returns `true` if this literal is byte literal string.
1653 pub fn is_bytestr(&self) -> bool {
1654 matches!(self, LitKind::ByteStr(_))
1657 /// Returns `true` if this is a numeric literal.
1658 pub fn is_numeric(&self) -> bool {
1659 matches!(self, LitKind::Int(..) | LitKind::Float(..))
1662 /// Returns `true` if this literal has no suffix.
1663 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1664 pub fn is_unsuffixed(&self) -> bool {
1668 /// Returns `true` if this literal has a suffix.
1669 pub fn is_suffixed(&self) -> bool {
1671 // suffixed variants
1672 LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
1673 | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
1674 // unsuffixed variants
1676 | LitKind::ByteStr(..)
1679 | LitKind::Int(_, LitIntType::Unsuffixed)
1680 | LitKind::Float(_, LitFloatType::Unsuffixed)
1682 | LitKind::Err(..) => false,
1687 // N.B., If you change this, you'll probably want to change the corresponding
1688 // type structure in `middle/ty.rs` as well.
1689 #[derive(Clone, Encodable, Decodable, Debug)]
1692 pub mutbl: Mutability,
1695 /// Represents a function's signature in a trait declaration,
1696 /// trait implementation, or free function.
1697 #[derive(Clone, Encodable, Decodable, Debug)]
1699 pub header: FnHeader,
1700 pub decl: P<FnDecl>,
1704 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1705 #[derive(Encodable, Decodable, HashStable_Generic)]
1712 pub fn name_str(self) -> &'static str {
1714 FloatTy::F32 => "f32",
1715 FloatTy::F64 => "f64",
1719 pub fn name(self) -> Symbol {
1721 FloatTy::F32 => sym::f32,
1722 FloatTy::F64 => sym::f64,
1726 pub fn bit_width(self) -> u64 {
1734 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1735 #[derive(Encodable, Decodable, HashStable_Generic)]
1746 pub fn name_str(&self) -> &'static str {
1748 IntTy::Isize => "isize",
1750 IntTy::I16 => "i16",
1751 IntTy::I32 => "i32",
1752 IntTy::I64 => "i64",
1753 IntTy::I128 => "i128",
1757 pub fn name(&self) -> Symbol {
1759 IntTy::Isize => sym::isize,
1760 IntTy::I8 => sym::i8,
1761 IntTy::I16 => sym::i16,
1762 IntTy::I32 => sym::i32,
1763 IntTy::I64 => sym::i64,
1764 IntTy::I128 => sym::i128,
1768 pub fn bit_width(&self) -> Option<u64> {
1770 IntTy::Isize => return None,
1779 pub fn normalize(&self, target_width: u32) -> Self {
1781 IntTy::Isize => match target_width {
1785 _ => unreachable!(),
1792 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
1793 #[derive(Encodable, Decodable, HashStable_Generic)]
1804 pub fn name_str(&self) -> &'static str {
1806 UintTy::Usize => "usize",
1808 UintTy::U16 => "u16",
1809 UintTy::U32 => "u32",
1810 UintTy::U64 => "u64",
1811 UintTy::U128 => "u128",
1815 pub fn name(&self) -> Symbol {
1817 UintTy::Usize => sym::usize,
1818 UintTy::U8 => sym::u8,
1819 UintTy::U16 => sym::u16,
1820 UintTy::U32 => sym::u32,
1821 UintTy::U64 => sym::u64,
1822 UintTy::U128 => sym::u128,
1826 pub fn bit_width(&self) -> Option<u64> {
1828 UintTy::Usize => return None,
1833 UintTy::U128 => 128,
1837 pub fn normalize(&self, target_width: u32) -> Self {
1839 UintTy::Usize => match target_width {
1843 _ => unreachable!(),
1850 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1851 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1852 #[derive(Clone, Encodable, Decodable, Debug)]
1853 pub struct AssocTyConstraint {
1856 pub gen_args: Option<GenericArgs>,
1857 pub kind: AssocTyConstraintKind,
1861 /// The kinds of an `AssocTyConstraint`.
1862 #[derive(Clone, Encodable, Decodable, Debug)]
1863 pub enum AssocTyConstraintKind {
1864 /// E.g., `A = Bar` in `Foo<A = Bar>`.
1865 Equality { ty: P<Ty> },
1866 /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
1867 Bound { bounds: GenericBounds },
1870 #[derive(Encodable, Decodable, Debug)]
1875 pub tokens: Option<LazyTokenStream>,
1879 fn clone(&self) -> Self {
1880 ensure_sufficient_stack(|| Self {
1882 kind: self.kind.clone(),
1884 tokens: self.tokens.clone(),
1890 pub fn peel_refs(&self) -> &Self {
1891 let mut final_ty = self;
1892 while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
1899 #[derive(Clone, Encodable, Decodable, Debug)]
1900 pub struct BareFnTy {
1901 pub unsafety: Unsafe,
1903 pub generic_params: Vec<GenericParam>,
1904 pub decl: P<FnDecl>,
1907 /// The various kinds of type recognized by the compiler.
1908 #[derive(Clone, Encodable, Decodable, Debug)]
1910 /// A variable-length slice (`[T]`).
1912 /// A fixed length array (`[T; n]`).
1913 Array(P<Ty>, AnonConst),
1914 /// A raw pointer (`*const T` or `*mut T`).
1916 /// A reference (`&'a T` or `&'a mut T`).
1917 Rptr(Option<Lifetime>, MutTy),
1918 /// A bare function (e.g., `fn(usize) -> bool`).
1919 BareFn(P<BareFnTy>),
1920 /// The never type (`!`).
1922 /// A tuple (`(A, B, C, D,...)`).
1924 /// A path (`module::module::...::Type`), optionally
1925 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
1927 /// Type parameters are stored in the `Path` itself.
1928 Path(Option<QSelf>, Path),
1929 /// A trait object type `Bound1 + Bound2 + Bound3`
1930 /// where `Bound` is a trait or a lifetime.
1931 TraitObject(GenericBounds, TraitObjectSyntax),
1932 /// An `impl Bound1 + Bound2 + Bound3` type
1933 /// where `Bound` is a trait or a lifetime.
1935 /// The `NodeId` exists to prevent lowering from having to
1936 /// generate `NodeId`s on the fly, which would complicate
1937 /// the generation of opaque `type Foo = impl Trait` items significantly.
1938 ImplTrait(NodeId, GenericBounds),
1939 /// No-op; kept solely so that we can pretty-print faithfully.
1943 /// This means the type should be inferred instead of it having been
1944 /// specified. This can appear anywhere in a type.
1946 /// Inferred type of a `self` or `&self` argument in a method.
1948 /// A macro in the type position.
1950 /// Placeholder for a kind that has failed to be defined.
1952 /// Placeholder for a `va_list`.
1957 pub fn is_implicit_self(&self) -> bool {
1958 matches!(self, TyKind::ImplicitSelf)
1961 pub fn is_unit(&self) -> bool {
1962 matches!(self, TyKind::Tup(tys) if tys.is_empty())
1966 /// Syntax used to declare a trait object.
1967 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1968 pub enum TraitObjectSyntax {
1973 /// Inline assembly operand explicit register or register class.
1975 /// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
1976 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1977 pub enum InlineAsmRegOrRegClass {
1982 bitflags::bitflags! {
1983 #[derive(Encodable, Decodable, HashStable_Generic)]
1984 pub struct InlineAsmOptions: u8 {
1985 const PURE = 1 << 0;
1986 const NOMEM = 1 << 1;
1987 const READONLY = 1 << 2;
1988 const PRESERVES_FLAGS = 1 << 3;
1989 const NORETURN = 1 << 4;
1990 const NOSTACK = 1 << 5;
1991 const ATT_SYNTAX = 1 << 6;
1995 #[derive(Clone, PartialEq, PartialOrd, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
1996 pub enum InlineAsmTemplatePiece {
1998 Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
2001 impl fmt::Display for InlineAsmTemplatePiece {
2002 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2004 Self::String(s) => {
2005 for c in s.chars() {
2007 '{' => f.write_str("{{")?,
2008 '}' => f.write_str("}}")?,
2014 Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
2015 write!(f, "{{{}:{}}}", operand_idx, modifier)
2017 Self::Placeholder { operand_idx, modifier: None, .. } => {
2018 write!(f, "{{{}}}", operand_idx)
2024 impl InlineAsmTemplatePiece {
2025 /// Rebuilds the asm template string from its pieces.
2026 pub fn to_string(s: &[Self]) -> String {
2028 let mut out = String::new();
2030 let _ = write!(out, "{}", p);
2036 /// Inline assembly operand.
2038 /// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
2039 #[derive(Clone, Encodable, Decodable, Debug)]
2040 pub enum InlineAsmOperand {
2042 reg: InlineAsmRegOrRegClass,
2046 reg: InlineAsmRegOrRegClass,
2048 expr: Option<P<Expr>>,
2051 reg: InlineAsmRegOrRegClass,
2056 reg: InlineAsmRegOrRegClass,
2059 out_expr: Option<P<Expr>>,
2069 /// Inline assembly.
2071 /// E.g., `asm!("NOP");`.
2072 #[derive(Clone, Encodable, Decodable, Debug)]
2073 pub struct InlineAsm {
2074 pub template: Vec<InlineAsmTemplatePiece>,
2075 pub operands: Vec<(InlineAsmOperand, Span)>,
2076 pub options: InlineAsmOptions,
2077 pub line_spans: Vec<Span>,
2080 /// Inline assembly dialect.
2082 /// E.g., `"intel"` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2083 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, Hash, HashStable_Generic)]
2084 pub enum LlvmAsmDialect {
2089 /// LLVM-style inline assembly.
2091 /// E.g., `"={eax}"(result)` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2092 #[derive(Clone, Encodable, Decodable, Debug)]
2093 pub struct LlvmInlineAsmOutput {
2094 pub constraint: Symbol,
2097 pub is_indirect: bool,
2100 /// LLVM-style inline assembly.
2102 /// E.g., `llvm_asm!("NOP");`.
2103 #[derive(Clone, Encodable, Decodable, Debug)]
2104 pub struct LlvmInlineAsm {
2106 pub asm_str_style: StrStyle,
2107 pub outputs: Vec<LlvmInlineAsmOutput>,
2108 pub inputs: Vec<(Symbol, P<Expr>)>,
2109 pub clobbers: Vec<Symbol>,
2111 pub alignstack: bool,
2112 pub dialect: LlvmAsmDialect,
2115 /// A parameter in a function header.
2117 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
2118 #[derive(Clone, Encodable, Decodable, Debug)]
2125 pub is_placeholder: bool,
2128 /// Alternative representation for `Arg`s describing `self` parameter of methods.
2130 /// E.g., `&mut self` as in `fn foo(&mut self)`.
2131 #[derive(Clone, Encodable, Decodable, Debug)]
2133 /// `self`, `mut self`
2135 /// `&'lt self`, `&'lt mut self`
2136 Region(Option<Lifetime>, Mutability),
2137 /// `self: TYPE`, `mut self: TYPE`
2138 Explicit(P<Ty>, Mutability),
2141 pub type ExplicitSelf = Spanned<SelfKind>;
2144 /// Attempts to cast parameter to `ExplicitSelf`.
2145 pub fn to_self(&self) -> Option<ExplicitSelf> {
2146 if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
2147 if ident.name == kw::SelfLower {
2148 return match self.ty.kind {
2149 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
2150 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
2151 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
2154 self.pat.span.to(self.ty.span),
2155 SelfKind::Explicit(self.ty.clone(), mutbl),
2163 /// Returns `true` if parameter is `self`.
2164 pub fn is_self(&self) -> bool {
2165 if let PatKind::Ident(_, ident, _) = self.pat.kind {
2166 ident.name == kw::SelfLower
2172 /// Builds a `Param` object from `ExplicitSelf`.
2173 pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
2174 let span = eself.span.to(eself_ident.span);
2175 let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
2176 let param = |mutbl, ty| Param {
2180 kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
2187 is_placeholder: false,
2190 SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
2191 SelfKind::Value(mutbl) => param(mutbl, infer_ty),
2192 SelfKind::Region(lt, mutbl) => param(
2196 kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
2205 /// A signature (not the body) of a function declaration.
2207 /// E.g., `fn foo(bar: baz)`.
2209 /// Please note that it's different from `FnHeader` structure
2210 /// which contains metadata about function safety, asyncness, constness and ABI.
2211 #[derive(Clone, Encodable, Decodable, Debug)]
2213 pub inputs: Vec<Param>,
2214 pub output: FnRetTy,
2218 pub fn get_self(&self) -> Option<ExplicitSelf> {
2219 self.inputs.get(0).and_then(Param::to_self)
2221 pub fn has_self(&self) -> bool {
2222 self.inputs.get(0).map_or(false, Param::is_self)
2224 pub fn c_variadic(&self) -> bool {
2225 self.inputs.last().map_or(false, |arg| matches!(arg.ty.kind, TyKind::CVarArgs))
2229 /// Is the trait definition an auto trait?
2230 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2236 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug)]
2237 #[derive(HashStable_Generic)]
2243 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2245 Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
2250 pub fn is_async(self) -> bool {
2251 matches!(self, Async::Yes { .. })
2254 /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
2255 pub fn opt_return_id(self) -> Option<NodeId> {
2257 Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
2263 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2264 #[derive(HashStable_Generic)]
2270 /// Item defaultness.
2271 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
2272 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2273 pub enum Defaultness {
2278 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
2279 pub enum ImplPolarity {
2280 /// `impl Trait for Type`
2282 /// `impl !Trait for Type`
2286 impl fmt::Debug for ImplPolarity {
2287 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2289 ImplPolarity::Positive => "positive".fmt(f),
2290 ImplPolarity::Negative(_) => "negative".fmt(f),
2295 #[derive(Clone, Encodable, Decodable, Debug)]
2297 /// Returns type is not specified.
2299 /// Functions default to `()` and closures default to inference.
2300 /// Span points to where return type would be inserted.
2302 /// Everything else.
2307 pub fn span(&self) -> Span {
2309 FnRetTy::Default(span) => span,
2310 FnRetTy::Ty(ref ty) => ty.span,
2315 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
2321 /// Module item kind.
2322 #[derive(Clone, Encodable, Decodable, Debug)]
2324 /// Module with inlined definition `mod foo { ... }`,
2325 /// or with definition outlined to a separate file `mod foo;` and already loaded from it.
2326 /// The inner span is from the first token past `{` to the last token until `}`,
2327 /// or from the first to the last token in the loaded file.
2328 Loaded(Vec<P<Item>>, Inline, Span),
2329 /// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
2333 /// Foreign module declaration.
2335 /// E.g., `extern { .. }` or `extern "C" { .. }`.
2336 #[derive(Clone, Encodable, Decodable, Debug)]
2337 pub struct ForeignMod {
2338 /// `unsafe` keyword accepted syntactically for macro DSLs, but not
2339 /// semantically by Rust.
2340 pub unsafety: Unsafe,
2341 pub abi: Option<StrLit>,
2342 pub items: Vec<P<ForeignItem>>,
2345 /// Global inline assembly.
2347 /// Also known as "module-level assembly" or "file-scoped assembly".
2348 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
2349 pub struct GlobalAsm {
2353 #[derive(Clone, Encodable, Decodable, Debug)]
2354 pub struct EnumDef {
2355 pub variants: Vec<Variant>,
2358 #[derive(Clone, Encodable, Decodable, Debug)]
2359 pub struct Variant {
2360 /// Attributes of the variant.
2361 pub attrs: Vec<Attribute>,
2362 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2366 /// The visibility of the variant. Syntactically accepted but not semantically.
2367 pub vis: Visibility,
2368 /// Name of the variant.
2371 /// Fields and constructor id of the variant.
2372 pub data: VariantData,
2373 /// Explicit discriminant, e.g., `Foo = 1`.
2374 pub disr_expr: Option<AnonConst>,
2375 /// Is a macro placeholder
2376 pub is_placeholder: bool,
2379 /// Part of `use` item to the right of its prefix.
2380 #[derive(Clone, Encodable, Decodable, Debug)]
2381 pub enum UseTreeKind {
2382 /// `use prefix` or `use prefix as rename`
2384 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2386 Simple(Option<Ident>, NodeId, NodeId),
2387 /// `use prefix::{...}`
2388 Nested(Vec<(UseTree, NodeId)>),
2393 /// A tree of paths sharing common prefixes.
2394 /// Used in `use` items both at top-level and inside of braces in import groups.
2395 #[derive(Clone, Encodable, Decodable, Debug)]
2396 pub struct UseTree {
2398 pub kind: UseTreeKind,
2403 pub fn ident(&self) -> Ident {
2405 UseTreeKind::Simple(Some(rename), ..) => rename,
2406 UseTreeKind::Simple(None, ..) => {
2407 self.prefix.segments.last().expect("empty prefix in a simple import").ident
2409 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2414 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2415 /// are contained as statements within items. These two cases need to be
2416 /// distinguished for pretty-printing.
2417 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
2418 pub enum AttrStyle {
2423 rustc_index::newtype_index! {
2426 DEBUG_FORMAT = "AttrId({})"
2430 impl<S: Encoder> rustc_serialize::Encodable<S> for AttrId {
2431 fn encode(&self, s: &mut S) -> Result<(), S::Error> {
2436 impl<D: Decoder> rustc_serialize::Decodable<D> for AttrId {
2437 fn decode(d: &mut D) -> Result<AttrId, D::Error> {
2438 d.read_nil().map(|_| crate::attr::mk_attr_id())
2442 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2443 pub struct AttrItem {
2446 pub tokens: Option<LazyTokenStream>,
2449 /// A list of attributes.
2450 pub type AttrVec = ThinVec<Attribute>;
2452 /// Metadata associated with an item.
2453 #[derive(Clone, Encodable, Decodable, Debug)]
2454 pub struct Attribute {
2457 /// Denotes if the attribute decorates the following construct (outer)
2458 /// or the construct this attribute is contained within (inner).
2459 pub style: AttrStyle,
2463 #[derive(Clone, Encodable, Decodable, Debug)]
2465 /// A normal attribute.
2466 Normal(AttrItem, Option<LazyTokenStream>),
2468 /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
2469 /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
2470 /// variant (which is much less compact and thus more expensive).
2471 DocComment(CommentKind, Symbol),
2474 /// `TraitRef`s appear in impls.
2476 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2477 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2478 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2479 /// same as the impl's `NodeId`).
2480 #[derive(Clone, Encodable, Decodable, Debug)]
2481 pub struct TraitRef {
2486 #[derive(Clone, Encodable, Decodable, Debug)]
2487 pub struct PolyTraitRef {
2488 /// The `'a` in `<'a> Foo<&'a T>`.
2489 pub bound_generic_params: Vec<GenericParam>,
2491 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2492 pub trait_ref: TraitRef,
2498 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2500 bound_generic_params: generic_params,
2501 trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
2507 #[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2508 pub enum CrateSugar {
2509 /// Source is `pub(crate)`.
2512 /// Source is (just) `crate`.
2516 #[derive(Clone, Encodable, Decodable, Debug)]
2517 pub struct Visibility {
2518 pub kind: VisibilityKind,
2520 pub tokens: Option<LazyTokenStream>,
2523 #[derive(Clone, Encodable, Decodable, Debug)]
2524 pub enum VisibilityKind {
2527 Restricted { path: P<Path>, id: NodeId },
2531 impl VisibilityKind {
2532 pub fn is_pub(&self) -> bool {
2533 matches!(self, VisibilityKind::Public)
2537 /// Field definition in a struct, variant or union.
2539 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2540 #[derive(Clone, Encodable, Decodable, Debug)]
2541 pub struct FieldDef {
2542 pub attrs: Vec<Attribute>,
2545 pub vis: Visibility,
2546 pub ident: Option<Ident>,
2549 pub is_placeholder: bool,
2552 /// Fields and constructor ids of enum variants and structs.
2553 #[derive(Clone, Encodable, Decodable, Debug)]
2554 pub enum VariantData {
2557 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2558 Struct(Vec<FieldDef>, bool),
2561 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2562 Tuple(Vec<FieldDef>, NodeId),
2565 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2570 /// Return the fields of this variant.
2571 pub fn fields(&self) -> &[FieldDef] {
2573 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
2578 /// Return the `NodeId` of this variant's constructor, if it has one.
2579 pub fn ctor_id(&self) -> Option<NodeId> {
2581 VariantData::Struct(..) => None,
2582 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2587 /// An item definition.
2588 #[derive(Clone, Encodable, Decodable, Debug)]
2589 pub struct Item<K = ItemKind> {
2590 pub attrs: Vec<Attribute>,
2593 pub vis: Visibility,
2594 /// The name of the item.
2595 /// It might be a dummy name in case of anonymous items.
2600 /// Original tokens this item was parsed from. This isn't necessarily
2601 /// available for all items, although over time more and more items should
2602 /// have this be `Some`. Right now this is primarily used for procedural
2603 /// macros, notably custom attributes.
2605 /// Note that the tokens here do not include the outer attributes, but will
2606 /// include inner attributes.
2607 pub tokens: Option<LazyTokenStream>,
2611 /// Return the span that encompasses the attributes.
2612 pub fn span_with_attributes(&self) -> Span {
2613 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2617 impl<K: Into<ItemKind>> Item<K> {
2618 pub fn into_item(self) -> Item {
2619 let Item { attrs, id, span, vis, ident, kind, tokens } = self;
2620 Item { attrs, id, span, vis, ident, kind: kind.into(), tokens }
2624 /// `extern` qualifier on a function item or function type.
2625 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2633 pub fn from_abi(abi: Option<StrLit>) -> Extern {
2634 abi.map_or(Extern::Implicit, Extern::Explicit)
2638 /// A function header.
2640 /// All the information between the visibility and the name of the function is
2641 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2642 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2643 pub struct FnHeader {
2644 pub unsafety: Unsafe,
2645 pub asyncness: Async,
2646 pub constness: Const,
2651 /// Does this function header have any qualifiers or is it empty?
2652 pub fn has_qualifiers(&self) -> bool {
2653 let Self { unsafety, asyncness, constness, ext } = self;
2654 matches!(unsafety, Unsafe::Yes(_))
2655 || asyncness.is_async()
2656 || matches!(constness, Const::Yes(_))
2657 || !matches!(ext, Extern::None)
2661 impl Default for FnHeader {
2662 fn default() -> FnHeader {
2664 unsafety: Unsafe::No,
2665 asyncness: Async::No,
2666 constness: Const::No,
2672 #[derive(Clone, Encodable, Decodable, Debug)]
2673 pub struct TraitKind(
2678 pub Vec<P<AssocItem>>,
2681 #[derive(Clone, Encodable, Decodable, Debug)]
2682 pub struct TyAliasKind(pub Defaultness, pub Generics, pub GenericBounds, pub Option<P<Ty>>);
2684 #[derive(Clone, Encodable, Decodable, Debug)]
2685 pub struct ImplKind {
2686 pub unsafety: Unsafe,
2687 pub polarity: ImplPolarity,
2688 pub defaultness: Defaultness,
2689 pub constness: Const,
2690 pub generics: Generics,
2692 /// The trait being implemented, if any.
2693 pub of_trait: Option<TraitRef>,
2696 pub items: Vec<P<AssocItem>>,
2699 #[derive(Clone, Encodable, Decodable, Debug)]
2700 pub struct FnKind(pub Defaultness, pub FnSig, pub Generics, pub Option<P<Block>>);
2702 #[derive(Clone, Encodable, Decodable, Debug)]
2704 /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
2706 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2707 ExternCrate(Option<Symbol>),
2708 /// A use declaration item (`use`).
2710 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2712 /// A static item (`static`).
2714 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2715 Static(P<Ty>, Mutability, Option<P<Expr>>),
2716 /// A constant item (`const`).
2718 /// E.g., `const FOO: i32 = 42;`.
2719 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2720 /// A function declaration (`fn`).
2722 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2724 /// A module declaration (`mod`).
2726 /// E.g., `mod foo;` or `mod foo { .. }`.
2727 /// `unsafe` keyword on modules is accepted syntactically for macro DSLs, but not
2728 /// semantically by Rust.
2729 Mod(Unsafe, ModKind),
2730 /// An external module (`extern`).
2732 /// E.g., `extern {}` or `extern "C" {}`.
2733 ForeignMod(ForeignMod),
2734 /// Module-level inline assembly (from `global_asm!()`).
2735 GlobalAsm(GlobalAsm),
2736 /// A type alias (`type`).
2738 /// E.g., `type Foo = Bar<u8>;`.
2739 TyAlias(Box<TyAliasKind>),
2740 /// An enum definition (`enum`).
2742 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2743 Enum(EnumDef, Generics),
2744 /// A struct definition (`struct`).
2746 /// E.g., `struct Foo<A> { x: A }`.
2747 Struct(VariantData, Generics),
2748 /// A union definition (`union`).
2750 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2751 Union(VariantData, Generics),
2752 /// A trait declaration (`trait`).
2754 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2755 Trait(Box<TraitKind>),
2758 /// E.g., `trait Foo = Bar + Quux;`.
2759 TraitAlias(Generics, GenericBounds),
2760 /// An implementation.
2762 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2763 Impl(Box<ImplKind>),
2764 /// A macro invocation.
2766 /// E.g., `foo!(..)`.
2769 /// A macro definition.
2773 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2774 rustc_data_structures::static_assert_size!(ItemKind, 112);
2777 pub fn article(&self) -> &str {
2780 Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
2781 | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
2782 ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
2786 pub fn descr(&self) -> &str {
2788 ItemKind::ExternCrate(..) => "extern crate",
2789 ItemKind::Use(..) => "`use` import",
2790 ItemKind::Static(..) => "static item",
2791 ItemKind::Const(..) => "constant item",
2792 ItemKind::Fn(..) => "function",
2793 ItemKind::Mod(..) => "module",
2794 ItemKind::ForeignMod(..) => "extern block",
2795 ItemKind::GlobalAsm(..) => "global asm item",
2796 ItemKind::TyAlias(..) => "type alias",
2797 ItemKind::Enum(..) => "enum",
2798 ItemKind::Struct(..) => "struct",
2799 ItemKind::Union(..) => "union",
2800 ItemKind::Trait(..) => "trait",
2801 ItemKind::TraitAlias(..) => "trait alias",
2802 ItemKind::MacCall(..) => "item macro invocation",
2803 ItemKind::MacroDef(..) => "macro definition",
2804 ItemKind::Impl { .. } => "implementation",
2808 pub fn generics(&self) -> Option<&Generics> {
2810 Self::Fn(box FnKind(_, _, generics, _))
2811 | Self::TyAlias(box TyAliasKind(_, generics, ..))
2812 | Self::Enum(_, generics)
2813 | Self::Struct(_, generics)
2814 | Self::Union(_, generics)
2815 | Self::Trait(box TraitKind(_, _, generics, ..))
2816 | Self::TraitAlias(generics, _)
2817 | Self::Impl(box ImplKind { generics, .. }) => Some(generics),
2823 /// Represents associated items.
2824 /// These include items in `impl` and `trait` definitions.
2825 pub type AssocItem = Item<AssocItemKind>;
2827 /// Represents associated item kinds.
2829 /// The term "provided" in the variants below refers to the item having a default
2830 /// definition / body. Meanwhile, a "required" item lacks a definition / body.
2831 /// In an implementation, all items must be provided.
2832 /// The `Option`s below denote the bodies, where `Some(_)`
2833 /// means "provided" and conversely `None` means "required".
2834 #[derive(Clone, Encodable, Decodable, Debug)]
2835 pub enum AssocItemKind {
2836 /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
2837 /// If `def` is parsed, then the constant is provided, and otherwise required.
2838 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2839 /// An associated function.
2841 /// An associated type.
2842 TyAlias(Box<TyAliasKind>),
2843 /// A macro expanding to associated items.
2847 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2848 rustc_data_structures::static_assert_size!(AssocItemKind, 72);
2850 impl AssocItemKind {
2851 pub fn defaultness(&self) -> Defaultness {
2853 Self::Const(def, ..)
2854 | Self::Fn(box FnKind(def, ..))
2855 | Self::TyAlias(box TyAliasKind(def, ..)) => def,
2856 Self::MacCall(..) => Defaultness::Final,
2861 impl From<AssocItemKind> for ItemKind {
2862 fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
2863 match assoc_item_kind {
2864 AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
2865 AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
2866 AssocItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
2867 AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
2872 impl TryFrom<ItemKind> for AssocItemKind {
2873 type Error = ItemKind;
2875 fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
2876 Ok(match item_kind {
2877 ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
2878 ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
2879 ItemKind::TyAlias(ty_alias_kind) => AssocItemKind::TyAlias(ty_alias_kind),
2880 ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
2881 _ => return Err(item_kind),
2886 /// An item in `extern` block.
2887 #[derive(Clone, Encodable, Decodable, Debug)]
2888 pub enum ForeignItemKind {
2889 /// A foreign static item (`static FOO: u8`).
2890 Static(P<Ty>, Mutability, Option<P<Expr>>),
2891 /// An foreign function.
2893 /// An foreign type.
2894 TyAlias(Box<TyAliasKind>),
2895 /// A macro expanding to foreign items.
2899 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2900 rustc_data_structures::static_assert_size!(ForeignItemKind, 72);
2902 impl From<ForeignItemKind> for ItemKind {
2903 fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
2904 match foreign_item_kind {
2905 ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
2906 ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
2907 ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
2908 ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
2913 impl TryFrom<ItemKind> for ForeignItemKind {
2914 type Error = ItemKind;
2916 fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
2917 Ok(match item_kind {
2918 ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
2919 ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
2920 ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
2921 ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
2922 _ => return Err(item_kind),
2927 pub type ForeignItem = Item<ForeignItemKind>;