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};
27 use crate::tokenstream::{DelimSpan, TokenStream, TokenTree};
29 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
30 use rustc_data_structures::sync::Lrc;
31 use rustc_data_structures::thin_vec::ThinVec;
32 use rustc_macros::HashStable_Generic;
33 use rustc_serialize::{self, Decoder, Encoder};
34 use rustc_span::source_map::{respan, Spanned};
35 use rustc_span::symbol::{kw, sym, Ident, Symbol};
36 use rustc_span::{Span, DUMMY_SP};
38 use std::cmp::Ordering;
39 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>,
101 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> 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.name.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 }
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 }
151 pub fn path_root(span: Span) -> Self {
152 PathSegment::from_ident(Ident::new(kw::PathRoot, span))
156 /// The arguments of a path segment.
158 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
159 #[derive(Clone, Encodable, Decodable, Debug)]
160 pub enum GenericArgs {
161 /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
162 AngleBracketed(AngleBracketedArgs),
163 /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
164 Parenthesized(ParenthesizedArgs),
168 pub fn is_parenthesized(&self) -> bool {
170 Parenthesized(..) => true,
175 pub fn is_angle_bracketed(&self) -> bool {
177 AngleBracketed(..) => true,
182 pub fn span(&self) -> Span {
184 AngleBracketed(ref data) => data.span,
185 Parenthesized(ref data) => data.span,
190 /// Concrete argument in the sequence of generic args.
191 #[derive(Clone, Encodable, Decodable, Debug)]
192 pub enum GenericArg {
193 /// `'a` in `Foo<'a>`
195 /// `Bar` in `Foo<Bar>`
202 pub fn span(&self) -> Span {
204 GenericArg::Lifetime(lt) => lt.ident.span,
205 GenericArg::Type(ty) => ty.span,
206 GenericArg::Const(ct) => ct.value.span,
211 /// A path like `Foo<'a, T>`.
212 #[derive(Clone, Encodable, Decodable, Debug, Default)]
213 pub struct AngleBracketedArgs {
214 /// The overall span.
216 /// The comma separated parts in the `<...>`.
217 pub args: Vec<AngleBracketedArg>,
220 /// Either an argument for a parameter e.g., `'a`, `Vec<u8>`, `0`,
221 /// or a constraint on an associated item, e.g., `Item = String` or `Item: Bound`.
222 #[derive(Clone, Encodable, Decodable, Debug)]
223 pub enum AngleBracketedArg {
224 /// Argument for a generic parameter.
226 /// Constraint for an associated item.
227 Constraint(AssocTyConstraint),
230 impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
231 fn into(self) -> Option<P<GenericArgs>> {
232 Some(P(GenericArgs::AngleBracketed(self)))
236 impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
237 fn into(self) -> Option<P<GenericArgs>> {
238 Some(P(GenericArgs::Parenthesized(self)))
242 /// A path like `Foo(A, B) -> C`.
243 #[derive(Clone, Encodable, Decodable, Debug)]
244 pub struct ParenthesizedArgs {
249 pub inputs: Vec<P<Ty>>,
255 impl ParenthesizedArgs {
256 pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
261 .map(|input| AngleBracketedArg::Arg(GenericArg::Type(input)))
263 AngleBracketedArgs { span: self.span, args }
267 pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
269 /// A modifier on a bound, e.g., `?Sized` or `?const Trait`.
271 /// Negative bounds should also be handled here.
272 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
273 pub enum TraitBoundModifier {
285 // This parses but will be rejected during AST validation.
289 /// The AST represents all type param bounds as types.
290 /// `typeck::collect::compute_bounds` matches these against
291 /// the "special" built-in traits (see `middle::lang_items`) and
292 /// detects `Copy`, `Send` and `Sync`.
293 #[derive(Clone, Encodable, Decodable, Debug)]
294 pub enum GenericBound {
295 Trait(PolyTraitRef, TraitBoundModifier),
300 pub fn span(&self) -> Span {
302 GenericBound::Trait(ref t, ..) => t.span,
303 GenericBound::Outlives(ref l) => l.ident.span,
308 pub type GenericBounds = Vec<GenericBound>;
310 /// Specifies the enforced ordering for generic parameters. In the future,
311 /// if we wanted to relax this order, we could override `PartialEq` and
312 /// `PartialOrd`, to allow the kinds to be unordered.
313 #[derive(Hash, Clone, Copy)]
314 pub enum ParamKindOrd {
317 // `unordered` is only `true` if `sess.has_features().const_generics`
318 // is active. Specifically, if it's only `min_const_generics`, it will still require
319 // ordering consts after types.
320 Const { unordered: bool },
323 impl Ord for ParamKindOrd {
324 fn cmp(&self, other: &Self) -> Ordering {
326 let to_int = |v| match v {
328 Type | Const { unordered: true } => 1,
329 // technically both consts should be ordered equally,
330 // but only one is ever encountered at a time, so this is
332 Const { unordered: false } => 2,
335 to_int(*self).cmp(&to_int(*other))
338 impl PartialOrd for ParamKindOrd {
339 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
340 Some(self.cmp(other))
343 impl PartialEq for ParamKindOrd {
344 fn eq(&self, other: &Self) -> bool {
345 self.cmp(other) == Ordering::Equal
348 impl Eq for ParamKindOrd {}
350 impl fmt::Display for ParamKindOrd {
351 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
353 ParamKindOrd::Lifetime => "lifetime".fmt(f),
354 ParamKindOrd::Type => "type".fmt(f),
355 ParamKindOrd::Const { .. } => "const".fmt(f),
360 #[derive(Clone, Encodable, Decodable, Debug)]
361 pub enum GenericParamKind {
362 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
365 default: Option<P<Ty>>,
369 /// Span of the `const` keyword.
374 #[derive(Clone, Encodable, Decodable, Debug)]
375 pub struct GenericParam {
379 pub bounds: GenericBounds,
380 pub is_placeholder: bool,
381 pub kind: GenericParamKind,
384 /// Represents lifetime, type and const parameters attached to a declaration of
385 /// a function, enum, trait, etc.
386 #[derive(Clone, Encodable, Decodable, Debug)]
387 pub struct Generics {
388 pub params: Vec<GenericParam>,
389 pub where_clause: WhereClause,
393 impl Default for Generics {
394 /// Creates an instance of `Generics`.
395 fn default() -> Generics {
398 where_clause: WhereClause {
399 has_where_token: false,
400 predicates: Vec::new(),
408 /// A where-clause in a definition.
409 #[derive(Clone, Encodable, Decodable, Debug)]
410 pub struct WhereClause {
411 /// `true` if we ate a `where` token: this can happen
412 /// if we parsed no predicates (e.g. `struct Foo where {}`).
413 /// This allows us to accurately pretty-print
414 /// in `nt_to_tokenstream`
415 pub has_where_token: bool,
416 pub predicates: Vec<WherePredicate>,
420 /// A single predicate in a where-clause.
421 #[derive(Clone, Encodable, Decodable, Debug)]
422 pub enum WherePredicate {
423 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
424 BoundPredicate(WhereBoundPredicate),
425 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
426 RegionPredicate(WhereRegionPredicate),
427 /// An equality predicate (unsupported).
428 EqPredicate(WhereEqPredicate),
431 impl WherePredicate {
432 pub fn span(&self) -> Span {
434 &WherePredicate::BoundPredicate(ref p) => p.span,
435 &WherePredicate::RegionPredicate(ref p) => p.span,
436 &WherePredicate::EqPredicate(ref p) => p.span,
443 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
444 #[derive(Clone, Encodable, Decodable, Debug)]
445 pub struct WhereBoundPredicate {
447 /// Any generics from a `for` binding.
448 pub bound_generic_params: Vec<GenericParam>,
449 /// The type being bounded.
450 pub bounded_ty: P<Ty>,
451 /// Trait and lifetime bounds (`Clone + Send + 'static`).
452 pub bounds: GenericBounds,
455 /// A lifetime predicate.
457 /// E.g., `'a: 'b + 'c`.
458 #[derive(Clone, Encodable, Decodable, Debug)]
459 pub struct WhereRegionPredicate {
461 pub lifetime: Lifetime,
462 pub bounds: GenericBounds,
465 /// An equality predicate (unsupported).
468 #[derive(Clone, Encodable, Decodable, Debug)]
469 pub struct WhereEqPredicate {
476 #[derive(Clone, Encodable, Decodable, Debug)]
479 pub attrs: Vec<Attribute>,
481 /// The order of items in the HIR is unrelated to the order of
482 /// items in the AST. However, we generate proc macro harnesses
483 /// based on the AST order, and later refer to these harnesses
484 /// from the HIR. This field keeps track of the order in which
485 /// we generated proc macros harnesses, so that we can map
486 /// HIR proc macros items back to their harness items.
487 pub proc_macros: Vec<NodeId>,
490 /// Possible values inside of compile-time attribute lists.
492 /// E.g., the '..' in `#[name(..)]`.
493 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
494 pub enum NestedMetaItem {
495 /// A full MetaItem, for recursive meta items.
499 /// E.g., `"foo"`, `64`, `true`.
503 /// A spanned compile-time attribute item.
505 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
506 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
507 pub struct MetaItem {
509 pub kind: MetaItemKind,
513 /// A compile-time attribute item.
515 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
516 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
517 pub enum MetaItemKind {
520 /// E.g., `test` as in `#[test]`.
524 /// E.g., `derive(..)` as in `#[derive(..)]`.
525 List(Vec<NestedMetaItem>),
526 /// Name value meta item.
528 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
532 /// A block (`{ .. }`).
534 /// E.g., `{ .. }` as in `fn foo() { .. }`.
535 #[derive(Clone, Encodable, Decodable, Debug)]
537 /// The statements in the block.
538 pub stmts: Vec<Stmt>,
540 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
541 pub rules: BlockCheckMode,
547 /// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
548 #[derive(Clone, Encodable, Decodable, Debug)]
553 pub tokens: Option<TokenStream>,
557 /// Attempt reparsing the pattern as a type.
558 /// This is intended for use by diagnostics.
559 pub fn to_ty(&self) -> Option<P<Ty>> {
560 let kind = match &self.kind {
561 // In a type expression `_` is an inference variable.
562 PatKind::Wild => TyKind::Infer,
563 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
564 PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
565 TyKind::Path(None, Path::from_ident(*ident))
567 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
568 PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
569 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
570 PatKind::Ref(pat, mutbl) => {
571 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
573 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
574 // when `P` can be reparsed as a type `T`.
575 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
576 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
577 // assuming `T0` to `Tn` are all syntactically valid as types.
578 PatKind::Tuple(pats) => {
579 let mut tys = Vec::with_capacity(pats.len());
580 // FIXME(#48994) - could just be collected into an Option<Vec>
582 tys.push(pat.to_ty()?);
589 Some(P(Ty { kind, id: self.id, span: self.span }))
592 /// Walk top-down and call `it` in each place where a pattern occurs
593 /// starting with the root pattern `walk` is called on. If `it` returns
594 /// false then we will descend no further but siblings will be processed.
595 pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
601 // Walk into the pattern associated with `Ident` (if any).
602 PatKind::Ident(_, _, Some(p)) => p.walk(it),
604 // Walk into each field of struct.
605 PatKind::Struct(_, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
607 // Sequence of patterns.
608 PatKind::TupleStruct(_, s) | PatKind::Tuple(s) | PatKind::Slice(s) | PatKind::Or(s) => {
609 s.iter().for_each(|p| p.walk(it))
612 // Trivial wrappers over inner patterns.
613 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
615 // These patterns do not contain subpatterns, skip.
622 | PatKind::MacCall(_) => {}
626 /// Is this a `..` pattern?
627 pub fn is_rest(&self) -> bool {
629 PatKind::Rest => true,
635 /// A single field in a struct pattern
637 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
638 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
639 /// except is_shorthand is true
640 #[derive(Clone, Encodable, Decodable, Debug)]
641 pub struct FieldPat {
642 /// The identifier for the field
644 /// The pattern the field is destructured to
646 pub is_shorthand: bool,
650 pub is_placeholder: bool,
653 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
654 pub enum BindingMode {
659 #[derive(Clone, Encodable, Decodable, Debug)]
661 Included(RangeSyntax),
665 #[derive(Clone, Encodable, Decodable, Debug)]
666 pub enum RangeSyntax {
673 #[derive(Clone, Encodable, Decodable, Debug)]
675 /// Represents a wildcard pattern (`_`).
678 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
679 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
680 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
681 /// during name resolution.
682 Ident(BindingMode, Ident, Option<P<Pat>>),
684 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
685 /// The `bool` is `true` in the presence of a `..`.
686 Struct(Path, Vec<FieldPat>, /* recovered */ bool),
688 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
689 TupleStruct(Path, Vec<P<Pat>>),
691 /// An or-pattern `A | B | C`.
692 /// Invariant: `pats.len() >= 2`.
695 /// A possibly qualified path pattern.
696 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
697 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
698 /// only legally refer to associated constants.
699 Path(Option<QSelf>, Path),
701 /// A tuple pattern (`(a, b)`).
707 /// A reference pattern (e.g., `&mut (a, b)`).
708 Ref(P<Pat>, Mutability),
713 /// A range pattern (e.g., `1...2`, `1..=2` or `1..2`).
714 Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
716 /// A slice pattern `[a, b, c]`.
719 /// A rest pattern `..`.
721 /// Syntactically it is valid anywhere.
723 /// Semantically however, it only has meaning immediately inside:
724 /// - a slice pattern: `[a, .., b]`,
725 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
726 /// - a tuple pattern: `(a, .., b)`,
727 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
729 /// In all of these cases, an additional restriction applies,
730 /// only one rest pattern may occur in the pattern sequences.
733 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
736 /// A macro pattern; pre-expansion.
740 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
741 #[derive(HashStable_Generic, Encodable, Decodable)]
742 pub enum Mutability {
748 /// Returns `MutMutable` only if both `self` and `other` are mutable.
749 pub fn and(self, other: Self) -> Self {
751 Mutability::Mut => other,
752 Mutability::Not => Mutability::Not,
756 pub fn invert(self) -> Self {
758 Mutability::Mut => Mutability::Not,
759 Mutability::Not => Mutability::Mut,
763 pub fn prefix_str(&self) -> &'static str {
765 Mutability::Mut => "mut ",
766 Mutability::Not => "",
771 /// The kind of borrow in an `AddrOf` expression,
772 /// e.g., `&place` or `&raw const place`.
773 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
774 #[derive(Encodable, Decodable, HashStable_Generic)]
775 pub enum BorrowKind {
776 /// A normal borrow, `&$expr` or `&mut $expr`.
777 /// The resulting type is either `&'a T` or `&'a mut T`
778 /// where `T = typeof($expr)` and `'a` is some lifetime.
780 /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
781 /// The resulting type is either `*const T` or `*mut T`
782 /// where `T = typeof($expr)`.
786 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
788 /// The `+` operator (addition)
790 /// The `-` operator (subtraction)
792 /// The `*` operator (multiplication)
794 /// The `/` operator (division)
796 /// The `%` operator (modulus)
798 /// The `&&` operator (logical and)
800 /// The `||` operator (logical or)
802 /// The `^` operator (bitwise xor)
804 /// The `&` operator (bitwise and)
806 /// The `|` operator (bitwise or)
808 /// The `<<` operator (shift left)
810 /// The `>>` operator (shift right)
812 /// The `==` operator (equality)
814 /// The `<` operator (less than)
816 /// The `<=` operator (less than or equal to)
818 /// The `!=` operator (not equal to)
820 /// The `>=` operator (greater than or equal to)
822 /// The `>` operator (greater than)
827 pub fn to_string(&self) -> &'static str {
850 pub fn lazy(&self) -> bool {
852 BinOpKind::And | BinOpKind::Or => true,
857 pub fn is_shift(&self) -> bool {
859 BinOpKind::Shl | BinOpKind::Shr => true,
864 pub fn is_comparison(&self) -> bool {
866 // Note for developers: please keep this as is;
867 // we want compilation to fail if another variant is added.
869 Eq | Lt | Le | Ne | Gt | Ge => true,
870 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
874 /// Returns `true` if the binary operator takes its arguments by value
875 pub fn is_by_value(&self) -> bool {
876 !self.is_comparison()
880 pub type BinOp = Spanned<BinOpKind>;
884 /// Note that `&data` is not an operator, it's an `AddrOf` expression.
885 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
887 /// The `*` operator for dereferencing
889 /// The `!` operator for logical inversion
891 /// The `-` operator for negation
896 /// Returns `true` if the unary operator takes its argument by value
897 pub fn is_by_value(u: UnOp) -> bool {
899 UnOp::Neg | UnOp::Not => true,
904 pub fn to_string(op: UnOp) -> &'static str {
914 #[derive(Clone, Encodable, Decodable, Debug)]
922 pub fn add_trailing_semicolon(mut self) -> Self {
923 self.kind = match self.kind {
924 StmtKind::Expr(expr) => StmtKind::Semi(expr),
925 StmtKind::MacCall(mac) => StmtKind::MacCall(
926 mac.map(|(mac, _style, attrs)| (mac, MacStmtStyle::Semicolon, attrs)),
933 pub fn is_item(&self) -> bool {
935 StmtKind::Item(_) => true,
940 pub fn is_expr(&self) -> bool {
942 StmtKind::Expr(_) => true,
948 #[derive(Clone, Encodable, Decodable, Debug)]
950 /// A local (let) binding.
952 /// An item definition.
954 /// Expr without trailing semi-colon.
956 /// Expr with a trailing semi-colon.
958 /// Just a trailing semi-colon.
961 MacCall(P<(MacCall, MacStmtStyle, AttrVec)>),
964 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
965 pub enum MacStmtStyle {
966 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
967 /// `foo!(...);`, `foo![...];`).
969 /// The macro statement had braces (e.g., `foo! { ... }`).
971 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
972 /// `foo!(...)`). All of these will end up being converted into macro
977 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
978 #[derive(Clone, Encodable, Decodable, Debug)]
982 pub ty: Option<P<Ty>>,
983 /// Initializer expression to set the value, if any.
984 pub init: Option<P<Expr>>,
989 /// An arm of a 'match'.
991 /// E.g., `0..=10 => { println!("match!") }` as in
995 /// 0..=10 => { println!("match!") },
996 /// _ => { println!("no match!") },
999 #[derive(Clone, Encodable, Decodable, Debug)]
1001 pub attrs: Vec<Attribute>,
1002 /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
1004 /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
1005 pub guard: Option<P<Expr>>,
1010 pub is_placeholder: bool,
1013 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1014 #[derive(Clone, Encodable, Decodable, Debug)]
1021 pub is_shorthand: bool,
1022 pub is_placeholder: bool,
1025 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1026 pub enum BlockCheckMode {
1028 Unsafe(UnsafeSource),
1031 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1032 pub enum UnsafeSource {
1037 /// A constant (expression) that's not an item or associated item,
1038 /// but needs its own `DefId` for type-checking, const-eval, etc.
1039 /// These are usually found nested inside types (e.g., array lengths)
1040 /// or expressions (e.g., repeat counts), and also used to define
1041 /// explicit discriminant values for enum variants.
1042 #[derive(Clone, Encodable, Decodable, Debug)]
1043 pub struct AnonConst {
1049 #[derive(Clone, Encodable, Decodable, Debug)]
1055 pub tokens: Option<TokenStream>,
1058 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
1059 #[cfg(target_arch = "x86_64")]
1060 rustc_data_structures::static_assert_size!(Expr, 104);
1063 /// Returns `true` if this expression would be valid somewhere that expects a value;
1064 /// for example, an `if` condition.
1065 pub fn returns(&self) -> bool {
1066 if let ExprKind::Block(ref block, _) = self.kind {
1067 match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
1069 Some(&StmtKind::Expr(_)) => true,
1070 Some(&StmtKind::Semi(ref expr)) => {
1071 if let ExprKind::Ret(_) = expr.kind {
1072 // Last statement is explicit return.
1078 // This is a block that doesn't end in either an implicit or explicit return.
1082 // This is not a block, it is a value.
1087 /// Is this expr either `N`, or `{ N }`.
1089 /// If this is not the case, name resolution does not resolve `N` when using
1090 /// `feature(min_const_generics)` as more complex expressions are not supported.
1091 pub fn is_potential_trivial_const_param(&self) -> bool {
1092 let this = if let ExprKind::Block(ref block, None) = self.kind {
1093 if block.stmts.len() == 1 {
1094 if let StmtKind::Expr(ref expr) = block.stmts[0].kind { expr } else { self }
1102 if let ExprKind::Path(None, ref path) = this.kind {
1103 if path.segments.len() == 1 && path.segments[0].args.is_none() {
1111 pub fn to_bound(&self) -> Option<GenericBound> {
1113 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1114 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1115 TraitBoundModifier::None,
1121 /// Attempts to reparse as `Ty` (for diagnostic purposes).
1122 pub fn to_ty(&self) -> Option<P<Ty>> {
1123 let kind = match &self.kind {
1124 // Trivial conversions.
1125 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1126 ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
1128 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1130 ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
1131 expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
1134 ExprKind::Repeat(expr, expr_len) => {
1135 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1138 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1140 ExprKind::Tup(exprs) => {
1141 let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
1145 // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
1146 // then type of result is trait object.
1147 // Otherwise we don't assume the result type.
1148 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1149 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1150 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1156 // This expression doesn't look like a type syntactically.
1160 Some(P(Ty { kind, id: self.id, span: self.span }))
1163 pub fn precedence(&self) -> ExprPrecedence {
1165 ExprKind::Box(_) => ExprPrecedence::Box,
1166 ExprKind::Array(_) => ExprPrecedence::Array,
1167 ExprKind::Call(..) => ExprPrecedence::Call,
1168 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1169 ExprKind::Tup(_) => ExprPrecedence::Tup,
1170 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1171 ExprKind::Unary(..) => ExprPrecedence::Unary,
1172 ExprKind::Lit(_) => ExprPrecedence::Lit,
1173 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1174 ExprKind::Let(..) => ExprPrecedence::Let,
1175 ExprKind::If(..) => ExprPrecedence::If,
1176 ExprKind::While(..) => ExprPrecedence::While,
1177 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1178 ExprKind::Loop(..) => ExprPrecedence::Loop,
1179 ExprKind::Match(..) => ExprPrecedence::Match,
1180 ExprKind::Closure(..) => ExprPrecedence::Closure,
1181 ExprKind::Block(..) => ExprPrecedence::Block,
1182 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1183 ExprKind::Async(..) => ExprPrecedence::Async,
1184 ExprKind::Await(..) => ExprPrecedence::Await,
1185 ExprKind::Assign(..) => ExprPrecedence::Assign,
1186 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1187 ExprKind::Field(..) => ExprPrecedence::Field,
1188 ExprKind::Index(..) => ExprPrecedence::Index,
1189 ExprKind::Range(..) => ExprPrecedence::Range,
1190 ExprKind::Path(..) => ExprPrecedence::Path,
1191 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1192 ExprKind::Break(..) => ExprPrecedence::Break,
1193 ExprKind::Continue(..) => ExprPrecedence::Continue,
1194 ExprKind::Ret(..) => ExprPrecedence::Ret,
1195 ExprKind::InlineAsm(..) | ExprKind::LlvmInlineAsm(..) => ExprPrecedence::InlineAsm,
1196 ExprKind::MacCall(..) => ExprPrecedence::Mac,
1197 ExprKind::Struct(..) => ExprPrecedence::Struct,
1198 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1199 ExprKind::Paren(..) => ExprPrecedence::Paren,
1200 ExprKind::Try(..) => ExprPrecedence::Try,
1201 ExprKind::Yield(..) => ExprPrecedence::Yield,
1202 ExprKind::Err => ExprPrecedence::Err,
1207 /// Limit types of a range (inclusive or exclusive)
1208 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
1209 pub enum RangeLimits {
1210 /// Inclusive at the beginning, exclusive at the end
1212 /// Inclusive at the beginning and end
1216 #[derive(Clone, Encodable, Decodable, Debug)]
1218 /// A `box x` expression.
1220 /// An array (`[a, b, c, d]`)
1221 Array(Vec<P<Expr>>),
1224 /// The first field resolves to the function itself,
1225 /// and the second field is the list of arguments.
1226 /// This also represents calling the constructor of
1227 /// tuple-like ADTs such as tuple structs and enum variants.
1228 Call(P<Expr>, Vec<P<Expr>>),
1229 /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1231 /// The `PathSegment` represents the method name and its generic arguments
1232 /// (within the angle brackets).
1233 /// The first element of the vector of an `Expr` is the expression that evaluates
1234 /// to the object on which the method is being called on (the receiver),
1235 /// and the remaining elements are the rest of the arguments.
1236 /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1237 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
1238 /// This `Span` is the span of the function, without the dot and receiver
1239 /// (e.g. `foo(a, b)` in `x.foo(a, b)`
1240 MethodCall(PathSegment, Vec<P<Expr>>, Span),
1241 /// A tuple (e.g., `(a, b, c, d)`).
1243 /// A binary operation (e.g., `a + b`, `a * b`).
1244 Binary(BinOp, P<Expr>, P<Expr>),
1245 /// A unary operation (e.g., `!x`, `*x`).
1246 Unary(UnOp, P<Expr>),
1247 /// A literal (e.g., `1`, `"foo"`).
1249 /// A cast (e.g., `foo as f64`).
1250 Cast(P<Expr>, P<Ty>),
1251 /// A type ascription (e.g., `42: usize`).
1252 Type(P<Expr>, P<Ty>),
1253 /// A `let pat = expr` expression that is only semantically allowed in the condition
1254 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1255 Let(P<Pat>, P<Expr>),
1256 /// An `if` block, with an optional `else` block.
1258 /// `if expr { block } else { expr }`
1259 If(P<Expr>, P<Block>, Option<P<Expr>>),
1260 /// A while loop, with an optional label.
1262 /// `'label: while expr { block }`
1263 While(P<Expr>, P<Block>, Option<Label>),
1264 /// A `for` loop, with an optional label.
1266 /// `'label: for pat in expr { block }`
1268 /// This is desugared to a combination of `loop` and `match` expressions.
1269 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1270 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1272 /// `'label: loop { block }`
1273 Loop(P<Block>, Option<Label>),
1274 /// A `match` block.
1275 Match(P<Expr>, Vec<Arm>),
1276 /// A closure (e.g., `move |a, b, c| a + b + c`).
1278 /// The final span is the span of the argument block `|...|`.
1279 Closure(CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
1280 /// A block (`'label: { ... }`).
1281 Block(P<Block>, Option<Label>),
1282 /// An async block (`async move { ... }`).
1284 /// The `NodeId` is the `NodeId` for the closure that results from
1285 /// desugaring an async block, just like the NodeId field in the
1286 /// `Async::Yes` variant. This is necessary in order to create a def for the
1287 /// closure which can be used as a parent of any child defs. Defs
1288 /// created during lowering cannot be made the parent of any other
1289 /// preexisting defs.
1290 Async(CaptureBy, NodeId, P<Block>),
1291 /// An await expression (`my_future.await`).
1294 /// A try block (`try { ... }`).
1297 /// An assignment (`a = foo()`).
1298 /// The `Span` argument is the span of the `=` token.
1299 Assign(P<Expr>, P<Expr>, Span),
1300 /// An assignment with an operator.
1303 AssignOp(BinOp, P<Expr>, P<Expr>),
1304 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1305 Field(P<Expr>, Ident),
1306 /// An indexing operation (e.g., `foo[2]`).
1307 Index(P<Expr>, P<Expr>),
1308 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
1309 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1311 /// Variable reference, possibly containing `::` and/or type
1312 /// parameters (e.g., `foo::bar::<baz>`).
1314 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1315 Path(Option<QSelf>, Path),
1317 /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
1318 AddrOf(BorrowKind, Mutability, P<Expr>),
1319 /// A `break`, with an optional label to break, and an optional expression.
1320 Break(Option<Label>, Option<P<Expr>>),
1321 /// A `continue`, with an optional label.
1322 Continue(Option<Label>),
1323 /// A `return`, with an optional value to be returned.
1324 Ret(Option<P<Expr>>),
1326 /// Output of the `asm!()` macro.
1327 InlineAsm(P<InlineAsm>),
1328 /// Output of the `llvm_asm!()` macro.
1329 LlvmInlineAsm(P<LlvmInlineAsm>),
1331 /// A macro invocation; pre-expansion.
1334 /// A struct literal expression.
1336 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. base}`,
1337 /// where `base` is the `Option<Expr>`.
1338 Struct(Path, Vec<Field>, Option<P<Expr>>),
1340 /// An array literal constructed from one repeated element.
1342 /// E.g., `[1; 5]`. The expression is the element to be
1343 /// repeated; the constant is the number of times to repeat it.
1344 Repeat(P<Expr>, AnonConst),
1346 /// No-op: used solely so we can pretty-print faithfully.
1349 /// A try expression (`expr?`).
1352 /// A `yield`, with an optional value to be yielded.
1353 Yield(Option<P<Expr>>),
1355 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1359 /// The explicit `Self` type in a "qualified path". The actual
1360 /// path, including the trait and the associated item, is stored
1361 /// separately. `position` represents the index of the associated
1362 /// item qualified with this `Self` type.
1364 /// ```ignore (only-for-syntax-highlight)
1365 /// <Vec<T> as a::b::Trait>::AssociatedItem
1366 /// ^~~~~ ~~~~~~~~~~~~~~^
1369 /// <Vec<T>>::AssociatedItem
1373 #[derive(Clone, Encodable, Decodable, Debug)]
1377 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1378 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1379 /// 0`, this is an empty span.
1380 pub path_span: Span,
1381 pub position: usize,
1384 /// A capture clause used in closures and `async` blocks.
1385 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1386 pub enum CaptureBy {
1387 /// `move |x| y + x`.
1389 /// `move` keyword was not specified.
1393 /// The movability of a generator / closure literal:
1394 /// whether a generator contains self-references, causing it to be `!Unpin`.
1395 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
1396 #[derive(HashStable_Generic)]
1397 pub enum Movability {
1398 /// May contain self-references, `!Unpin`.
1400 /// Must not contain self-references, `Unpin`.
1404 /// Represents a macro invocation. The `path` indicates which macro
1405 /// is being invoked, and the `args` are arguments passed to it.
1406 #[derive(Clone, Encodable, Decodable, Debug)]
1407 pub struct MacCall {
1409 pub args: P<MacArgs>,
1410 pub prior_type_ascription: Option<(Span, bool)>,
1414 pub fn span(&self) -> Span {
1415 self.path.span.to(self.args.span().unwrap_or(self.path.span))
1419 /// Arguments passed to an attribute or a function-like macro.
1420 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1422 /// No arguments - `#[attr]`.
1424 /// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
1425 Delimited(DelimSpan, MacDelimiter, TokenStream),
1426 /// Arguments of a key-value attribute - `#[attr = "value"]`.
1428 /// Span of the `=` token.
1430 /// Token stream of the "value".
1436 pub fn delim(&self) -> DelimToken {
1438 MacArgs::Delimited(_, delim, _) => delim.to_token(),
1439 MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
1443 pub fn span(&self) -> Option<Span> {
1445 MacArgs::Empty => None,
1446 MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
1447 MacArgs::Eq(eq_span, ref tokens) => Some(eq_span.to(tokens.span().unwrap_or(eq_span))),
1451 /// Tokens inside the delimiters or after `=`.
1452 /// Proc macros see these tokens, for example.
1453 pub fn inner_tokens(&self) -> TokenStream {
1455 MacArgs::Empty => TokenStream::default(),
1456 MacArgs::Delimited(.., tokens) | MacArgs::Eq(.., tokens) => tokens.clone(),
1460 /// Tokens together with the delimiters or `=`.
1461 /// Use of this method generally means that something suboptimal or hacky is happening.
1462 pub fn outer_tokens(&self) -> TokenStream {
1464 MacArgs::Empty => TokenStream::default(),
1465 MacArgs::Delimited(dspan, delim, ref tokens) => {
1466 TokenTree::Delimited(dspan, delim.to_token(), tokens.clone()).into()
1468 MacArgs::Eq(eq_span, ref tokens) => {
1469 iter::once(TokenTree::token(token::Eq, eq_span)).chain(tokens.trees()).collect()
1474 /// Whether a macro with these arguments needs a semicolon
1475 /// when used as a standalone item or statement.
1476 pub fn need_semicolon(&self) -> bool {
1477 !matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
1481 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
1482 pub enum MacDelimiter {
1489 pub fn to_token(self) -> DelimToken {
1491 MacDelimiter::Parenthesis => DelimToken::Paren,
1492 MacDelimiter::Bracket => DelimToken::Bracket,
1493 MacDelimiter::Brace => DelimToken::Brace,
1497 pub fn from_token(delim: DelimToken) -> Option<MacDelimiter> {
1499 token::Paren => Some(MacDelimiter::Parenthesis),
1500 token::Bracket => Some(MacDelimiter::Bracket),
1501 token::Brace => Some(MacDelimiter::Brace),
1502 token::NoDelim => None,
1507 /// Represents a macro definition.
1508 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1509 pub struct MacroDef {
1510 pub body: P<MacArgs>,
1511 /// `true` if macro was defined with `macro_rules`.
1512 pub macro_rules: bool,
1515 #[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
1516 #[derive(HashStable_Generic)]
1518 /// A regular string, like `"foo"`.
1520 /// A raw string, like `r##"foo"##`.
1522 /// The value is the number of `#` symbols used.
1527 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1529 /// The original literal token as written in source code.
1530 pub token: token::Lit,
1531 /// The "semantic" representation of the literal lowered from the original tokens.
1532 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1533 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1538 /// Same as `Lit`, but restricted to string literals.
1539 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1541 /// The original literal token as written in source code.
1542 pub style: StrStyle,
1544 pub suffix: Option<Symbol>,
1546 /// The unescaped "semantic" representation of the literal lowered from the original token.
1547 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1548 pub symbol_unescaped: Symbol,
1552 pub fn as_lit(&self) -> Lit {
1553 let token_kind = match self.style {
1554 StrStyle::Cooked => token::Str,
1555 StrStyle::Raw(n) => token::StrRaw(n),
1558 token: token::Lit::new(token_kind, self.symbol, self.suffix),
1560 kind: LitKind::Str(self.symbol_unescaped, self.style),
1565 /// Type of the integer literal based on provided suffix.
1566 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1567 #[derive(HashStable_Generic)]
1568 pub enum LitIntType {
1577 /// Type of the float literal based on provided suffix.
1578 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1579 #[derive(HashStable_Generic)]
1580 pub enum LitFloatType {
1581 /// A float literal with a suffix (`1f32` or `1E10f32`).
1583 /// A float literal without a suffix (`1.0 or 1.0E10`).
1589 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
1590 #[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
1592 /// A string literal (`"foo"`).
1593 Str(Symbol, StrStyle),
1594 /// A byte string (`b"foo"`).
1595 ByteStr(Lrc<Vec<u8>>),
1596 /// A byte char (`b'f'`).
1598 /// A character literal (`'a'`).
1600 /// An integer literal (`1`).
1601 Int(u128, LitIntType),
1602 /// A float literal (`1f64` or `1E10f64`).
1603 Float(Symbol, LitFloatType),
1604 /// A boolean literal.
1606 /// Placeholder for a literal that wasn't well-formed in some way.
1611 /// Returns `true` if this literal is a string.
1612 pub fn is_str(&self) -> bool {
1614 LitKind::Str(..) => true,
1619 /// Returns `true` if this literal is byte literal string.
1620 pub fn is_bytestr(&self) -> bool {
1622 LitKind::ByteStr(_) => true,
1627 /// Returns `true` if this is a numeric literal.
1628 pub fn is_numeric(&self) -> bool {
1630 LitKind::Int(..) | LitKind::Float(..) => true,
1635 /// Returns `true` if this literal has no suffix.
1636 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1637 pub fn is_unsuffixed(&self) -> bool {
1641 /// Returns `true` if this literal has a suffix.
1642 pub fn is_suffixed(&self) -> bool {
1644 // suffixed variants
1645 LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
1646 | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
1647 // unsuffixed variants
1649 | LitKind::ByteStr(..)
1652 | LitKind::Int(_, LitIntType::Unsuffixed)
1653 | LitKind::Float(_, LitFloatType::Unsuffixed)
1655 | LitKind::Err(..) => false,
1660 // N.B., If you change this, you'll probably want to change the corresponding
1661 // type structure in `middle/ty.rs` as well.
1662 #[derive(Clone, Encodable, Decodable, Debug)]
1665 pub mutbl: Mutability,
1668 /// Represents a function's signature in a trait declaration,
1669 /// trait implementation, or free function.
1670 #[derive(Clone, Encodable, Decodable, Debug)]
1672 pub header: FnHeader,
1673 pub decl: P<FnDecl>,
1676 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1677 #[derive(Encodable, Decodable, HashStable_Generic)]
1684 pub fn name_str(self) -> &'static str {
1686 FloatTy::F32 => "f32",
1687 FloatTy::F64 => "f64",
1691 pub fn name(self) -> Symbol {
1693 FloatTy::F32 => sym::f32,
1694 FloatTy::F64 => sym::f64,
1698 pub fn bit_width(self) -> u64 {
1706 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1707 #[derive(Encodable, Decodable, HashStable_Generic)]
1718 pub fn name_str(&self) -> &'static str {
1720 IntTy::Isize => "isize",
1722 IntTy::I16 => "i16",
1723 IntTy::I32 => "i32",
1724 IntTy::I64 => "i64",
1725 IntTy::I128 => "i128",
1729 pub fn name(&self) -> Symbol {
1731 IntTy::Isize => sym::isize,
1732 IntTy::I8 => sym::i8,
1733 IntTy::I16 => sym::i16,
1734 IntTy::I32 => sym::i32,
1735 IntTy::I64 => sym::i64,
1736 IntTy::I128 => sym::i128,
1740 pub fn val_to_string(&self, val: i128) -> String {
1741 // Cast to a `u128` so we can correctly print `INT128_MIN`. All integral types
1742 // are parsed as `u128`, so we wouldn't want to print an extra negative
1744 format!("{}{}", val as u128, self.name_str())
1747 pub fn bit_width(&self) -> Option<u64> {
1749 IntTy::Isize => return None,
1758 pub fn normalize(&self, target_width: u32) -> Self {
1760 IntTy::Isize => match target_width {
1764 _ => unreachable!(),
1771 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
1772 #[derive(Encodable, Decodable, HashStable_Generic)]
1783 pub fn name_str(&self) -> &'static str {
1785 UintTy::Usize => "usize",
1787 UintTy::U16 => "u16",
1788 UintTy::U32 => "u32",
1789 UintTy::U64 => "u64",
1790 UintTy::U128 => "u128",
1794 pub fn name(&self) -> Symbol {
1796 UintTy::Usize => sym::usize,
1797 UintTy::U8 => sym::u8,
1798 UintTy::U16 => sym::u16,
1799 UintTy::U32 => sym::u32,
1800 UintTy::U64 => sym::u64,
1801 UintTy::U128 => sym::u128,
1805 pub fn val_to_string(&self, val: u128) -> String {
1806 format!("{}{}", val, self.name_str())
1809 pub fn bit_width(&self) -> Option<u64> {
1811 UintTy::Usize => return None,
1816 UintTy::U128 => 128,
1820 pub fn normalize(&self, target_width: u32) -> Self {
1822 UintTy::Usize => match target_width {
1826 _ => unreachable!(),
1833 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1834 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1835 #[derive(Clone, Encodable, Decodable, Debug)]
1836 pub struct AssocTyConstraint {
1839 pub kind: AssocTyConstraintKind,
1843 /// The kinds of an `AssocTyConstraint`.
1844 #[derive(Clone, Encodable, Decodable, Debug)]
1845 pub enum AssocTyConstraintKind {
1846 /// E.g., `A = Bar` in `Foo<A = Bar>`.
1847 Equality { ty: P<Ty> },
1848 /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
1849 Bound { bounds: GenericBounds },
1852 #[derive(Clone, Encodable, Decodable, Debug)]
1859 #[derive(Clone, Encodable, Decodable, Debug)]
1860 pub struct BareFnTy {
1861 pub unsafety: Unsafe,
1863 pub generic_params: Vec<GenericParam>,
1864 pub decl: P<FnDecl>,
1867 /// The various kinds of type recognized by the compiler.
1868 #[derive(Clone, Encodable, Decodable, Debug)]
1870 /// A variable-length slice (`[T]`).
1872 /// A fixed length array (`[T; n]`).
1873 Array(P<Ty>, AnonConst),
1874 /// A raw pointer (`*const T` or `*mut T`).
1876 /// A reference (`&'a T` or `&'a mut T`).
1877 Rptr(Option<Lifetime>, MutTy),
1878 /// A bare function (e.g., `fn(usize) -> bool`).
1879 BareFn(P<BareFnTy>),
1880 /// The never type (`!`).
1882 /// A tuple (`(A, B, C, D,...)`).
1884 /// A path (`module::module::...::Type`), optionally
1885 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
1887 /// Type parameters are stored in the `Path` itself.
1888 Path(Option<QSelf>, Path),
1889 /// A trait object type `Bound1 + Bound2 + Bound3`
1890 /// where `Bound` is a trait or a lifetime.
1891 TraitObject(GenericBounds, TraitObjectSyntax),
1892 /// An `impl Bound1 + Bound2 + Bound3` type
1893 /// where `Bound` is a trait or a lifetime.
1895 /// The `NodeId` exists to prevent lowering from having to
1896 /// generate `NodeId`s on the fly, which would complicate
1897 /// the generation of opaque `type Foo = impl Trait` items significantly.
1898 ImplTrait(NodeId, GenericBounds),
1899 /// No-op; kept solely so that we can pretty-print faithfully.
1903 /// This means the type should be inferred instead of it having been
1904 /// specified. This can appear anywhere in a type.
1906 /// Inferred type of a `self` or `&self` argument in a method.
1908 /// A macro in the type position.
1910 /// Placeholder for a kind that has failed to be defined.
1912 /// Placeholder for a `va_list`.
1917 pub fn is_implicit_self(&self) -> bool {
1918 if let TyKind::ImplicitSelf = *self { true } else { false }
1921 pub fn is_unit(&self) -> bool {
1922 if let TyKind::Tup(ref tys) = *self { tys.is_empty() } else { false }
1926 /// Syntax used to declare a trait object.
1927 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
1928 pub enum TraitObjectSyntax {
1933 /// Inline assembly operand explicit register or register class.
1935 /// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
1936 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1937 pub enum InlineAsmRegOrRegClass {
1942 bitflags::bitflags! {
1943 #[derive(Encodable, Decodable, HashStable_Generic)]
1944 pub struct InlineAsmOptions: u8 {
1945 const PURE = 1 << 0;
1946 const NOMEM = 1 << 1;
1947 const READONLY = 1 << 2;
1948 const PRESERVES_FLAGS = 1 << 3;
1949 const NORETURN = 1 << 4;
1950 const NOSTACK = 1 << 5;
1951 const ATT_SYNTAX = 1 << 6;
1955 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1956 pub enum InlineAsmTemplatePiece {
1958 Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
1961 impl fmt::Display for InlineAsmTemplatePiece {
1962 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1964 Self::String(s) => {
1965 for c in s.chars() {
1967 '{' => f.write_str("{{")?,
1968 '}' => f.write_str("}}")?,
1974 Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
1975 write!(f, "{{{}:{}}}", operand_idx, modifier)
1977 Self::Placeholder { operand_idx, modifier: None, .. } => {
1978 write!(f, "{{{}}}", operand_idx)
1984 impl InlineAsmTemplatePiece {
1985 /// Rebuilds the asm template string from its pieces.
1986 pub fn to_string(s: &[Self]) -> String {
1988 let mut out = String::new();
1990 let _ = write!(out, "{}", p);
1996 /// Inline assembly operand.
1998 /// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
1999 #[derive(Clone, Encodable, Decodable, Debug)]
2000 pub enum InlineAsmOperand {
2002 reg: InlineAsmRegOrRegClass,
2006 reg: InlineAsmRegOrRegClass,
2008 expr: Option<P<Expr>>,
2011 reg: InlineAsmRegOrRegClass,
2016 reg: InlineAsmRegOrRegClass,
2019 out_expr: Option<P<Expr>>,
2029 /// Inline assembly.
2031 /// E.g., `asm!("NOP");`.
2032 #[derive(Clone, Encodable, Decodable, Debug)]
2033 pub struct InlineAsm {
2034 pub template: Vec<InlineAsmTemplatePiece>,
2035 pub operands: Vec<(InlineAsmOperand, Span)>,
2036 pub options: InlineAsmOptions,
2037 pub line_spans: Vec<Span>,
2040 /// Inline assembly dialect.
2042 /// E.g., `"intel"` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2043 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
2044 pub enum LlvmAsmDialect {
2049 /// LLVM-style inline assembly.
2051 /// E.g., `"={eax}"(result)` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2052 #[derive(Clone, Encodable, Decodable, Debug)]
2053 pub struct LlvmInlineAsmOutput {
2054 pub constraint: Symbol,
2057 pub is_indirect: bool,
2060 /// LLVM-style inline assembly.
2062 /// E.g., `llvm_asm!("NOP");`.
2063 #[derive(Clone, Encodable, Decodable, Debug)]
2064 pub struct LlvmInlineAsm {
2066 pub asm_str_style: StrStyle,
2067 pub outputs: Vec<LlvmInlineAsmOutput>,
2068 pub inputs: Vec<(Symbol, P<Expr>)>,
2069 pub clobbers: Vec<Symbol>,
2071 pub alignstack: bool,
2072 pub dialect: LlvmAsmDialect,
2075 /// A parameter in a function header.
2077 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
2078 #[derive(Clone, Encodable, Decodable, Debug)]
2085 pub is_placeholder: bool,
2088 /// Alternative representation for `Arg`s describing `self` parameter of methods.
2090 /// E.g., `&mut self` as in `fn foo(&mut self)`.
2091 #[derive(Clone, Encodable, Decodable, Debug)]
2093 /// `self`, `mut self`
2095 /// `&'lt self`, `&'lt mut self`
2096 Region(Option<Lifetime>, Mutability),
2097 /// `self: TYPE`, `mut self: TYPE`
2098 Explicit(P<Ty>, Mutability),
2101 pub type ExplicitSelf = Spanned<SelfKind>;
2104 /// Attempts to cast parameter to `ExplicitSelf`.
2105 pub fn to_self(&self) -> Option<ExplicitSelf> {
2106 if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
2107 if ident.name == kw::SelfLower {
2108 return match self.ty.kind {
2109 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
2110 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
2111 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
2114 self.pat.span.to(self.ty.span),
2115 SelfKind::Explicit(self.ty.clone(), mutbl),
2123 /// Returns `true` if parameter is `self`.
2124 pub fn is_self(&self) -> bool {
2125 if let PatKind::Ident(_, ident, _) = self.pat.kind {
2126 ident.name == kw::SelfLower
2132 /// Builds a `Param` object from `ExplicitSelf`.
2133 pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
2134 let span = eself.span.to(eself_ident.span);
2135 let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span });
2136 let param = |mutbl, ty| Param {
2140 kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
2147 is_placeholder: false,
2150 SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
2151 SelfKind::Value(mutbl) => param(mutbl, infer_ty),
2152 SelfKind::Region(lt, mutbl) => param(
2156 kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
2164 /// A signature (not the body) of a function declaration.
2166 /// E.g., `fn foo(bar: baz)`.
2168 /// Please note that it's different from `FnHeader` structure
2169 /// which contains metadata about function safety, asyncness, constness and ABI.
2170 #[derive(Clone, Encodable, Decodable, Debug)]
2172 pub inputs: Vec<Param>,
2173 pub output: FnRetTy,
2177 pub fn get_self(&self) -> Option<ExplicitSelf> {
2178 self.inputs.get(0).and_then(Param::to_self)
2180 pub fn has_self(&self) -> bool {
2181 self.inputs.get(0).map_or(false, Param::is_self)
2183 pub fn c_variadic(&self) -> bool {
2184 self.inputs.last().map_or(false, |arg| match arg.ty.kind {
2185 TyKind::CVarArgs => true,
2191 /// Is the trait definition an auto trait?
2192 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2198 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug)]
2199 #[derive(HashStable_Generic)]
2205 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2207 Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
2212 pub fn is_async(self) -> bool {
2213 if let Async::Yes { .. } = self { true } else { false }
2216 /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
2217 pub fn opt_return_id(self) -> Option<NodeId> {
2219 Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
2225 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2226 #[derive(HashStable_Generic)]
2232 /// Item defaultness.
2233 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
2234 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2235 pub enum Defaultness {
2240 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
2241 pub enum ImplPolarity {
2242 /// `impl Trait for Type`
2244 /// `impl !Trait for Type`
2248 impl fmt::Debug for ImplPolarity {
2249 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2251 ImplPolarity::Positive => "positive".fmt(f),
2252 ImplPolarity::Negative(_) => "negative".fmt(f),
2257 #[derive(Clone, Encodable, Decodable, Debug)]
2259 /// Returns type is not specified.
2261 /// Functions default to `()` and closures default to inference.
2262 /// Span points to where return type would be inserted.
2264 /// Everything else.
2269 pub fn span(&self) -> Span {
2271 FnRetTy::Default(span) => span,
2272 FnRetTy::Ty(ref ty) => ty.span,
2277 /// Module declaration.
2279 /// E.g., `mod foo;` or `mod foo { .. }`.
2280 #[derive(Clone, Encodable, Decodable, Debug, Default)]
2282 /// A span from the first token past `{` to the last token until `}`.
2283 /// For `mod foo;`, the inner span ranges from the first token
2284 /// to the last token in the external file.
2286 pub items: Vec<P<Item>>,
2287 /// `true` for `mod foo { .. }`; `false` for `mod foo;`.
2291 /// Foreign module declaration.
2293 /// E.g., `extern { .. }` or `extern C { .. }`.
2294 #[derive(Clone, Encodable, Decodable, Debug)]
2295 pub struct ForeignMod {
2296 pub abi: Option<StrLit>,
2297 pub items: Vec<P<ForeignItem>>,
2300 /// Global inline assembly.
2302 /// Also known as "module-level assembly" or "file-scoped assembly".
2303 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
2304 pub struct GlobalAsm {
2308 #[derive(Clone, Encodable, Decodable, Debug)]
2309 pub struct EnumDef {
2310 pub variants: Vec<Variant>,
2313 #[derive(Clone, Encodable, Decodable, Debug)]
2314 pub struct Variant {
2315 /// Attributes of the variant.
2316 pub attrs: Vec<Attribute>,
2317 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2321 /// The visibility of the variant. Syntactically accepted but not semantically.
2322 pub vis: Visibility,
2323 /// Name of the variant.
2326 /// Fields and constructor id of the variant.
2327 pub data: VariantData,
2328 /// Explicit discriminant, e.g., `Foo = 1`.
2329 pub disr_expr: Option<AnonConst>,
2330 /// Is a macro placeholder
2331 pub is_placeholder: bool,
2334 /// Part of `use` item to the right of its prefix.
2335 #[derive(Clone, Encodable, Decodable, Debug)]
2336 pub enum UseTreeKind {
2337 /// `use prefix` or `use prefix as rename`
2339 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2341 Simple(Option<Ident>, NodeId, NodeId),
2342 /// `use prefix::{...}`
2343 Nested(Vec<(UseTree, NodeId)>),
2348 /// A tree of paths sharing common prefixes.
2349 /// Used in `use` items both at top-level and inside of braces in import groups.
2350 #[derive(Clone, Encodable, Decodable, Debug)]
2351 pub struct UseTree {
2353 pub kind: UseTreeKind,
2358 pub fn ident(&self) -> Ident {
2360 UseTreeKind::Simple(Some(rename), ..) => rename,
2361 UseTreeKind::Simple(None, ..) => {
2362 self.prefix.segments.last().expect("empty prefix in a simple import").ident
2364 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2369 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2370 /// are contained as statements within items. These two cases need to be
2371 /// distinguished for pretty-printing.
2372 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
2373 pub enum AttrStyle {
2378 rustc_index::newtype_index! {
2381 DEBUG_FORMAT = "AttrId({})"
2385 impl<S: Encoder> rustc_serialize::Encodable<S> for AttrId {
2386 fn encode(&self, s: &mut S) -> Result<(), S::Error> {
2391 impl<D: Decoder> rustc_serialize::Decodable<D> for AttrId {
2392 fn decode(d: &mut D) -> Result<AttrId, D::Error> {
2393 d.read_nil().map(|_| crate::attr::mk_attr_id())
2397 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2398 pub struct AttrItem {
2403 /// A list of attributes.
2404 pub type AttrVec = ThinVec<Attribute>;
2406 /// Metadata associated with an item.
2407 #[derive(Clone, Encodable, Decodable, Debug)]
2408 pub struct Attribute {
2411 /// Denotes if the attribute decorates the following construct (outer)
2412 /// or the construct this attribute is contained within (inner).
2413 pub style: AttrStyle,
2417 #[derive(Clone, Encodable, Decodable, Debug)]
2419 /// A normal attribute.
2422 /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
2423 /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
2424 /// variant (which is much less compact and thus more expensive).
2425 DocComment(CommentKind, Symbol),
2428 /// `TraitRef`s appear in impls.
2430 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2431 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2432 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2433 /// same as the impl's `NodeId`).
2434 #[derive(Clone, Encodable, Decodable, Debug)]
2435 pub struct TraitRef {
2440 #[derive(Clone, Encodable, Decodable, Debug)]
2441 pub struct PolyTraitRef {
2442 /// The `'a` in `<'a> Foo<&'a T>`.
2443 pub bound_generic_params: Vec<GenericParam>,
2445 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2446 pub trait_ref: TraitRef,
2452 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2454 bound_generic_params: generic_params,
2455 trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
2461 #[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2462 pub enum CrateSugar {
2463 /// Source is `pub(crate)`.
2466 /// Source is (just) `crate`.
2470 pub type Visibility = Spanned<VisibilityKind>;
2472 #[derive(Clone, Encodable, Decodable, Debug)]
2473 pub enum VisibilityKind {
2476 Restricted { path: P<Path>, id: NodeId },
2480 impl VisibilityKind {
2481 pub fn is_pub(&self) -> bool {
2482 if let VisibilityKind::Public = *self { true } else { false }
2486 /// Field of a struct.
2488 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2489 #[derive(Clone, Encodable, Decodable, Debug)]
2490 pub struct StructField {
2491 pub attrs: Vec<Attribute>,
2494 pub vis: Visibility,
2495 pub ident: Option<Ident>,
2498 pub is_placeholder: bool,
2501 /// Fields and constructor ids of enum variants and structs.
2502 #[derive(Clone, Encodable, Decodable, Debug)]
2503 pub enum VariantData {
2506 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2507 Struct(Vec<StructField>, bool),
2510 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2511 Tuple(Vec<StructField>, NodeId),
2514 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2519 /// Return the fields of this variant.
2520 pub fn fields(&self) -> &[StructField] {
2522 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
2527 /// Return the `NodeId` of this variant's constructor, if it has one.
2528 pub fn ctor_id(&self) -> Option<NodeId> {
2530 VariantData::Struct(..) => None,
2531 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2536 /// An item definition.
2537 #[derive(Clone, Encodable, Decodable, Debug)]
2538 pub struct Item<K = ItemKind> {
2539 pub attrs: Vec<Attribute>,
2542 pub vis: Visibility,
2543 /// The name of the item.
2544 /// It might be a dummy name in case of anonymous items.
2549 /// Original tokens this item was parsed from. This isn't necessarily
2550 /// available for all items, although over time more and more items should
2551 /// have this be `Some`. Right now this is primarily used for procedural
2552 /// macros, notably custom attributes.
2554 /// Note that the tokens here do not include the outer attributes, but will
2555 /// include inner attributes.
2556 pub tokens: Option<TokenStream>,
2560 /// Return the span that encompasses the attributes.
2561 pub fn span_with_attributes(&self) -> Span {
2562 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2566 impl<K: Into<ItemKind>> Item<K> {
2567 pub fn into_item(self) -> Item {
2568 let Item { attrs, id, span, vis, ident, kind, tokens } = self;
2569 Item { attrs, id, span, vis, ident, kind: kind.into(), tokens }
2573 /// `extern` qualifier on a function item or function type.
2574 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2582 pub fn from_abi(abi: Option<StrLit>) -> Extern {
2583 abi.map_or(Extern::Implicit, Extern::Explicit)
2587 /// A function header.
2589 /// All the information between the visibility and the name of the function is
2590 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2591 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2592 pub struct FnHeader {
2593 pub unsafety: Unsafe,
2594 pub asyncness: Async,
2595 pub constness: Const,
2600 /// Does this function header have any qualifiers or is it empty?
2601 pub fn has_qualifiers(&self) -> bool {
2602 let Self { unsafety, asyncness, constness, ext } = self;
2603 matches!(unsafety, Unsafe::Yes(_))
2604 || asyncness.is_async()
2605 || matches!(constness, Const::Yes(_))
2606 || !matches!(ext, Extern::None)
2610 impl Default for FnHeader {
2611 fn default() -> FnHeader {
2613 unsafety: Unsafe::No,
2614 asyncness: Async::No,
2615 constness: Const::No,
2621 #[derive(Clone, Encodable, Decodable, Debug)]
2623 /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
2625 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2626 ExternCrate(Option<Symbol>),
2627 /// A use declaration item (`use`).
2629 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2631 /// A static item (`static`).
2633 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2634 Static(P<Ty>, Mutability, Option<P<Expr>>),
2635 /// A constant item (`const`).
2637 /// E.g., `const FOO: i32 = 42;`.
2638 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2639 /// A function declaration (`fn`).
2641 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2642 Fn(Defaultness, FnSig, Generics, Option<P<Block>>),
2643 /// A module declaration (`mod`).
2645 /// E.g., `mod foo;` or `mod foo { .. }`.
2647 /// An external module (`extern`).
2649 /// E.g., `extern {}` or `extern "C" {}`.
2650 ForeignMod(ForeignMod),
2651 /// Module-level inline assembly (from `global_asm!()`).
2652 GlobalAsm(P<GlobalAsm>),
2653 /// A type alias (`type`).
2655 /// E.g., `type Foo = Bar<u8>;`.
2656 TyAlias(Defaultness, Generics, GenericBounds, Option<P<Ty>>),
2657 /// An enum definition (`enum`).
2659 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2660 Enum(EnumDef, Generics),
2661 /// A struct definition (`struct`).
2663 /// E.g., `struct Foo<A> { x: A }`.
2664 Struct(VariantData, Generics),
2665 /// A union definition (`union`).
2667 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2668 Union(VariantData, Generics),
2669 /// A trait declaration (`trait`).
2671 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2672 Trait(IsAuto, Unsafe, Generics, GenericBounds, Vec<P<AssocItem>>),
2675 /// E.g., `trait Foo = Bar + Quux;`.
2676 TraitAlias(Generics, GenericBounds),
2677 /// An implementation.
2679 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2682 polarity: ImplPolarity,
2683 defaultness: Defaultness,
2687 /// The trait being implemented, if any.
2688 of_trait: Option<TraitRef>,
2691 items: Vec<P<AssocItem>>,
2693 /// A macro invocation.
2695 /// E.g., `foo!(..)`.
2698 /// A macro definition.
2703 pub fn article(&self) -> &str {
2706 Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
2707 | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
2708 ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
2712 pub fn descr(&self) -> &str {
2714 ItemKind::ExternCrate(..) => "extern crate",
2715 ItemKind::Use(..) => "`use` import",
2716 ItemKind::Static(..) => "static item",
2717 ItemKind::Const(..) => "constant item",
2718 ItemKind::Fn(..) => "function",
2719 ItemKind::Mod(..) => "module",
2720 ItemKind::ForeignMod(..) => "extern block",
2721 ItemKind::GlobalAsm(..) => "global asm item",
2722 ItemKind::TyAlias(..) => "type alias",
2723 ItemKind::Enum(..) => "enum",
2724 ItemKind::Struct(..) => "struct",
2725 ItemKind::Union(..) => "union",
2726 ItemKind::Trait(..) => "trait",
2727 ItemKind::TraitAlias(..) => "trait alias",
2728 ItemKind::MacCall(..) => "item macro invocation",
2729 ItemKind::MacroDef(..) => "macro definition",
2730 ItemKind::Impl { .. } => "implementation",
2734 pub fn generics(&self) -> Option<&Generics> {
2736 Self::Fn(_, _, generics, _)
2737 | Self::TyAlias(_, generics, ..)
2738 | Self::Enum(_, generics)
2739 | Self::Struct(_, generics)
2740 | Self::Union(_, generics)
2741 | Self::Trait(_, _, generics, ..)
2742 | Self::TraitAlias(generics, _)
2743 | Self::Impl { generics, .. } => Some(generics),
2749 /// Represents associated items.
2750 /// These include items in `impl` and `trait` definitions.
2751 pub type AssocItem = Item<AssocItemKind>;
2753 /// Represents associated item kinds.
2755 /// The term "provided" in the variants below refers to the item having a default
2756 /// definition / body. Meanwhile, a "required" item lacks a definition / body.
2757 /// In an implementation, all items must be provided.
2758 /// The `Option`s below denote the bodies, where `Some(_)`
2759 /// means "provided" and conversely `None` means "required".
2760 #[derive(Clone, Encodable, Decodable, Debug)]
2761 pub enum AssocItemKind {
2762 /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
2763 /// If `def` is parsed, then the constant is provided, and otherwise required.
2764 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2765 /// An associated function.
2766 Fn(Defaultness, FnSig, Generics, Option<P<Block>>),
2767 /// An associated type.
2768 TyAlias(Defaultness, Generics, GenericBounds, Option<P<Ty>>),
2769 /// A macro expanding to associated items.
2773 impl AssocItemKind {
2774 pub fn defaultness(&self) -> Defaultness {
2776 Self::Const(def, ..) | Self::Fn(def, ..) | Self::TyAlias(def, ..) => def,
2777 Self::MacCall(..) => Defaultness::Final,
2782 impl From<AssocItemKind> for ItemKind {
2783 fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
2784 match assoc_item_kind {
2785 AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
2786 AssocItemKind::Fn(a, b, c, d) => ItemKind::Fn(a, b, c, d),
2787 AssocItemKind::TyAlias(a, b, c, d) => ItemKind::TyAlias(a, b, c, d),
2788 AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
2793 impl TryFrom<ItemKind> for AssocItemKind {
2794 type Error = ItemKind;
2796 fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
2797 Ok(match item_kind {
2798 ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
2799 ItemKind::Fn(a, b, c, d) => AssocItemKind::Fn(a, b, c, d),
2800 ItemKind::TyAlias(a, b, c, d) => AssocItemKind::TyAlias(a, b, c, d),
2801 ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
2802 _ => return Err(item_kind),
2807 /// An item in `extern` block.
2808 #[derive(Clone, Encodable, Decodable, Debug)]
2809 pub enum ForeignItemKind {
2810 /// A foreign static item (`static FOO: u8`).
2811 Static(P<Ty>, Mutability, Option<P<Expr>>),
2812 /// A foreign function.
2813 Fn(Defaultness, FnSig, Generics, Option<P<Block>>),
2815 TyAlias(Defaultness, Generics, GenericBounds, Option<P<Ty>>),
2816 /// A macro expanding to foreign items.
2820 impl From<ForeignItemKind> for ItemKind {
2821 fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
2822 match foreign_item_kind {
2823 ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
2824 ForeignItemKind::Fn(a, b, c, d) => ItemKind::Fn(a, b, c, d),
2825 ForeignItemKind::TyAlias(a, b, c, d) => ItemKind::TyAlias(a, b, c, d),
2826 ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
2831 impl TryFrom<ItemKind> for ForeignItemKind {
2832 type Error = ItemKind;
2834 fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
2835 Ok(match item_kind {
2836 ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
2837 ItemKind::Fn(a, b, c, d) => ForeignItemKind::Fn(a, b, c, d),
2838 ItemKind::TyAlias(a, b, c, d) => ForeignItemKind::TyAlias(a, b, c, d),
2839 ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
2840 _ => return Err(item_kind),
2845 pub type ForeignItem = Item<ForeignItemKind>;