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rust/compiler/rustc_ast/src/ast.rs
bors af68f7182e Auto merge of #96016 - Aaron1011:hash-name-cleanup, r=cjgillot 
Remove last vestiges of skippng ident span hashing

This removes a comment that no longer applies, and properly hashes
the full ident for path segments.
2022-04-17 10:31:52 +00:00

2975 lines
90 KiB
Rust
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//! The Rust abstract syntax tree module.
//!
//! This module contains common structures forming the language AST.
//! Two main entities in the module are [`Item`] (which represents an AST element with
//! additional metadata), and [`ItemKind`] (which represents a concrete type and contains
//! information specific to the type of the item).
//!
//! Other module items worth mentioning:
//! - [`Ty`] and [`TyKind`]: A parsed Rust type.
//! - [`Expr`] and [`ExprKind`]: A parsed Rust expression.
//! - [`Pat`] and [`PatKind`]: A parsed Rust pattern. Patterns are often dual to expressions.
//! - [`Stmt`] and [`StmtKind`]: An executable action that does not return a value.
//! - [`FnDecl`], [`FnHeader`] and [`Param`]: Metadata associated with a function declaration.
//! - [`Generics`], [`GenericParam`], [`WhereClause`]: Metadata associated with generic parameters.
//! - [`EnumDef`] and [`Variant`]: Enum declaration.
//! - [`Lit`] and [`LitKind`]: Literal expressions.
//! - [`MacroDef`], [`MacStmtStyle`], [`MacCall`], [`MacDelimiter`]: Macro definition and invocation.
//! - [`Attribute`]: Metadata associated with item.
//! - [`UnOp`], [`BinOp`], and [`BinOpKind`]: Unary and binary operators.
pub use crate::util::parser::ExprPrecedence;
pub use GenericArgs::*;
pub use UnsafeSource::*;
use crate::ptr::P;
use crate::token::{self, CommentKind, DelimToken, Token};
use crate::tokenstream::{DelimSpan, LazyTokenStream, TokenStream, TokenTree};
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_data_structures::sync::Lrc;
use rustc_data_structures::thin_vec::ThinVec;
use rustc_macros::HashStable_Generic;
use rustc_serialize::{self, Decoder, Encoder};
use rustc_span::source_map::{respan, Spanned};
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{Span, DUMMY_SP};
use std::cmp::Ordering;
use std::convert::TryFrom;
use std::fmt;
use std::mem;
#[cfg(test)]
mod tests;
/// A "Label" is an identifier of some point in sources,
/// e.g. in the following code:
///
/// ```rust
/// 'outer: loop {
/// break 'outer;
/// }
/// ```
///
/// `'outer` is a label.
#[derive(Clone, Encodable, Decodable, Copy, HashStable_Generic, Eq, PartialEq)]
pub struct Label {
pub ident: Ident,
}
impl fmt::Debug for Label {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "label({:?})", self.ident)
}
}
/// A "Lifetime" is an annotation of the scope in which variable
/// can be used, e.g. `'a` in `&'a i32`.
#[derive(Clone, Encodable, Decodable, Copy)]
pub struct Lifetime {
pub id: NodeId,
pub ident: Ident,
}
impl fmt::Debug for Lifetime {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "lifetime({}: {})", self.id, self)
}
}
impl fmt::Display for Lifetime {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.ident.name)
}
}
/// A "Path" is essentially Rust's notion of a name.
///
/// It's represented as a sequence of identifiers,
/// along with a bunch of supporting information.
///
/// E.g., `std::cmp::PartialEq`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Path {
pub span: Span,
/// The segments in the path: the things separated by `::`.
/// Global paths begin with `kw::PathRoot`.
pub segments: Vec<PathSegment>,
pub tokens: Option<LazyTokenStream>,
}
impl PartialEq<Symbol> for Path {
#[inline]
fn eq(&self, symbol: &Symbol) -> bool {
self.segments.len() == 1 && { self.segments[0].ident.name == *symbol }
}
}
impl<CTX: rustc_span::HashStableContext> HashStable<CTX> for Path {
fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
self.segments.len().hash_stable(hcx, hasher);
for segment in &self.segments {
segment.ident.hash_stable(hcx, hasher);
}
}
}
impl Path {
// Convert a span and an identifier to the corresponding
// one-segment path.
pub fn from_ident(ident: Ident) -> Path {
Path { segments: vec![PathSegment::from_ident(ident)], span: ident.span, tokens: None }
}
pub fn is_global(&self) -> bool {
!self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
}
}
/// A segment of a path: an identifier, an optional lifetime, and a set of types.
///
/// E.g., `std`, `String` or `Box<T>`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct PathSegment {
/// The identifier portion of this path segment.
pub ident: Ident,
pub id: NodeId,
/// Type/lifetime parameters attached to this path. They come in
/// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
/// `None` means that no parameter list is supplied (`Path`),
/// `Some` means that parameter list is supplied (`Path<X, Y>`)
/// but it can be empty (`Path<>`).
/// `P` is used as a size optimization for the common case with no parameters.
pub args: Option<P<GenericArgs>>,
}
impl PathSegment {
pub fn from_ident(ident: Ident) -> Self {
PathSegment { ident, id: DUMMY_NODE_ID, args: None }
}
pub fn path_root(span: Span) -> Self {
PathSegment::from_ident(Ident::new(kw::PathRoot, span))
}
pub fn span(&self) -> Span {
match &self.args {
Some(args) => self.ident.span.to(args.span()),
None => self.ident.span,
}
}
}
/// The arguments of a path segment.
///
/// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum GenericArgs {
/// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
AngleBracketed(AngleBracketedArgs),
/// The `(A, B)` and `C` in `Foo(A, B) -> C`.
Parenthesized(ParenthesizedArgs),
}
impl GenericArgs {
pub fn is_angle_bracketed(&self) -> bool {
matches!(self, AngleBracketed(..))
}
pub fn span(&self) -> Span {
match *self {
AngleBracketed(ref data) => data.span,
Parenthesized(ref data) => data.span,
}
}
}
/// Concrete argument in the sequence of generic args.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum GenericArg {
/// `'a` in `Foo<'a>`
Lifetime(Lifetime),
/// `Bar` in `Foo<Bar>`
Type(P<Ty>),
/// `1` in `Foo<1>`
Const(AnonConst),
}
impl GenericArg {
pub fn span(&self) -> Span {
match self {
GenericArg::Lifetime(lt) => lt.ident.span,
GenericArg::Type(ty) => ty.span,
GenericArg::Const(ct) => ct.value.span,
}
}
}
/// A path like `Foo<'a, T>`.
#[derive(Clone, Encodable, Decodable, Debug, Default)]
pub struct AngleBracketedArgs {
/// The overall span.
pub span: Span,
/// The comma separated parts in the `<...>`.
pub args: Vec<AngleBracketedArg>,
}
/// Either an argument for a parameter e.g., `'a`, `Vec<u8>`, `0`,
/// or a constraint on an associated item, e.g., `Item = String` or `Item: Bound`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum AngleBracketedArg {
/// Argument for a generic parameter.
Arg(GenericArg),
/// Constraint for an associated item.
Constraint(AssocConstraint),
}
impl AngleBracketedArg {
pub fn span(&self) -> Span {
match self {
AngleBracketedArg::Arg(arg) => arg.span(),
AngleBracketedArg::Constraint(constraint) => constraint.span,
}
}
}
impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
fn into(self) -> Option<P<GenericArgs>> {
Some(P(GenericArgs::AngleBracketed(self)))
}
}
impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
fn into(self) -> Option<P<GenericArgs>> {
Some(P(GenericArgs::Parenthesized(self)))
}
}
/// A path like `Foo(A, B) -> C`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct ParenthesizedArgs {
/// ```text
/// Foo(A, B) -> C
/// ^^^^^^^^^^^^^^
/// ```
pub span: Span,
/// `(A, B)`
pub inputs: Vec<P<Ty>>,
/// ```text
/// Foo(A, B) -> C
/// ^^^^^^
/// ```
pub inputs_span: Span,
/// `C`
pub output: FnRetTy,
}
impl ParenthesizedArgs {
pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
let args = self
.inputs
.iter()
.cloned()
.map(|input| AngleBracketedArg::Arg(GenericArg::Type(input)))
.collect();
AngleBracketedArgs { span: self.inputs_span, args }
}
}
pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
/// A modifier on a bound, e.g., `?Trait` or `~const Trait`.
///
/// Negative bounds should also be handled here.
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
pub enum TraitBoundModifier {
/// No modifiers
None,
/// `?Trait`
Maybe,
/// `~const Trait`
MaybeConst,
/// `~const ?Trait`
//
// This parses but will be rejected during AST validation.
MaybeConstMaybe,
}
/// The AST represents all type param bounds as types.
/// `typeck::collect::compute_bounds` matches these against
/// the "special" built-in traits (see `middle::lang_items`) and
/// detects `Copy`, `Send` and `Sync`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum GenericBound {
Trait(PolyTraitRef, TraitBoundModifier),
Outlives(Lifetime),
}
impl GenericBound {
pub fn span(&self) -> Span {
match self {
GenericBound::Trait(ref t, ..) => t.span,
GenericBound::Outlives(ref l) => l.ident.span,
}
}
}
pub type GenericBounds = Vec<GenericBound>;
/// Specifies the enforced ordering for generic parameters. In the future,
/// if we wanted to relax this order, we could override `PartialEq` and
/// `PartialOrd`, to allow the kinds to be unordered.
#[derive(Hash, Clone, Copy)]
pub enum ParamKindOrd {
Lifetime,
Type,
Const,
// `Infer` is not actually constructed directly from the AST, but is implicitly constructed
// during HIR lowering, and `ParamKindOrd` will implicitly order inferred variables last.
Infer,
}
impl Ord for ParamKindOrd {
fn cmp(&self, other: &Self) -> Ordering {
use ParamKindOrd::*;
let to_int = |v| match v {
Lifetime => 0,
Infer | Type | Const => 1,
};
to_int(*self).cmp(&to_int(*other))
}
}
impl PartialOrd for ParamKindOrd {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for ParamKindOrd {
fn eq(&self, other: &Self) -> bool {
self.cmp(other) == Ordering::Equal
}
}
impl Eq for ParamKindOrd {}
impl fmt::Display for ParamKindOrd {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
ParamKindOrd::Lifetime => "lifetime".fmt(f),
ParamKindOrd::Type => "type".fmt(f),
ParamKindOrd::Const { .. } => "const".fmt(f),
ParamKindOrd::Infer => "infer".fmt(f),
}
}
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum GenericParamKind {
/// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
Lifetime,
Type {
default: Option<P<Ty>>,
},
Const {
ty: P<Ty>,
/// Span of the `const` keyword.
kw_span: Span,
/// Optional default value for the const generic param
default: Option<AnonConst>,
},
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct GenericParam {
pub id: NodeId,
pub ident: Ident,
pub attrs: AttrVec,
pub bounds: GenericBounds,
pub is_placeholder: bool,
pub kind: GenericParamKind,
}
impl GenericParam {
pub fn span(&self) -> Span {
match &self.kind {
GenericParamKind::Lifetime | GenericParamKind::Type { default: None } => {
self.ident.span
}
GenericParamKind::Type { default: Some(ty) } => self.ident.span.to(ty.span),
GenericParamKind::Const { kw_span, default: Some(default), .. } => {
kw_span.to(default.value.span)
}
GenericParamKind::Const { kw_span, default: None, ty } => kw_span.to(ty.span),
}
}
}
/// Represents lifetime, type and const parameters attached to a declaration of
/// a function, enum, trait, etc.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Generics {
pub params: Vec<GenericParam>,
pub where_clause: WhereClause,
pub span: Span,
}
impl Default for Generics {
/// Creates an instance of `Generics`.
fn default() -> Generics {
Generics {
params: Vec::new(),
where_clause: WhereClause {
has_where_token: false,
predicates: Vec::new(),
span: DUMMY_SP,
},
span: DUMMY_SP,
}
}
}
/// A where-clause in a definition.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct WhereClause {
/// `true` if we ate a `where` token: this can happen
/// if we parsed no predicates (e.g. `struct Foo where {}`).
/// This allows us to accurately pretty-print
/// in `nt_to_tokenstream`
pub has_where_token: bool,
pub predicates: Vec<WherePredicate>,
pub span: Span,
}
/// A single predicate in a where-clause.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum WherePredicate {
/// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
BoundPredicate(WhereBoundPredicate),
/// A lifetime predicate (e.g., `'a: 'b + 'c`).
RegionPredicate(WhereRegionPredicate),
/// An equality predicate (unsupported).
EqPredicate(WhereEqPredicate),
}
impl WherePredicate {
pub fn span(&self) -> Span {
match self {
WherePredicate::BoundPredicate(p) => p.span,
WherePredicate::RegionPredicate(p) => p.span,
WherePredicate::EqPredicate(p) => p.span,
}
}
}
/// A type bound.
///
/// E.g., `for<'c> Foo: Send + Clone + 'c`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct WhereBoundPredicate {
pub span: Span,
/// Any generics from a `for` binding.
pub bound_generic_params: Vec<GenericParam>,
/// The type being bounded.
pub bounded_ty: P<Ty>,
/// Trait and lifetime bounds (`Clone + Send + 'static`).
pub bounds: GenericBounds,
}
/// A lifetime predicate.
///
/// E.g., `'a: 'b + 'c`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct WhereRegionPredicate {
pub span: Span,
pub lifetime: Lifetime,
pub bounds: GenericBounds,
}
/// An equality predicate (unsupported).
///
/// E.g., `T = int`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct WhereEqPredicate {
pub id: NodeId,
pub span: Span,
pub lhs_ty: P<Ty>,
pub rhs_ty: P<Ty>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Crate {
pub attrs: Vec<Attribute>,
pub items: Vec<P<Item>>,
pub spans: ModSpans,
/// Must be equal to `CRATE_NODE_ID` after the crate root is expanded, but may hold
/// expansion placeholders or an unassigned value (`DUMMY_NODE_ID`) before that.
pub id: NodeId,
pub is_placeholder: bool,
}
/// Possible values inside of compile-time attribute lists.
///
/// E.g., the '..' in `#[name(..)]`.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum NestedMetaItem {
/// A full MetaItem, for recursive meta items.
MetaItem(MetaItem),
/// A literal.
///
/// E.g., `"foo"`, `64`, `true`.
Literal(Lit),
}
/// A spanned compile-time attribute item.
///
/// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct MetaItem {
pub path: Path,
pub kind: MetaItemKind,
pub span: Span,
}
/// A compile-time attribute item.
///
/// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum MetaItemKind {
/// Word meta item.
///
/// E.g., `test` as in `#[test]`.
Word,
/// List meta item.
///
/// E.g., `derive(..)` as in `#[derive(..)]`.
List(Vec<NestedMetaItem>),
/// Name value meta item.
///
/// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
NameValue(Lit),
}
/// A block (`{ .. }`).
///
/// E.g., `{ .. }` as in `fn foo() { .. }`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Block {
/// The statements in the block.
pub stmts: Vec<Stmt>,
pub id: NodeId,
/// Distinguishes between `unsafe { ... }` and `{ ... }`.
pub rules: BlockCheckMode,
pub span: Span,
pub tokens: Option<LazyTokenStream>,
/// The following *isn't* a parse error, but will cause multiple errors in following stages.
/// ```
/// let x = {
/// foo: var
/// };
/// ```
/// #34255
pub could_be_bare_literal: bool,
}
/// A match pattern.
///
/// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Pat {
pub id: NodeId,
pub kind: PatKind,
pub span: Span,
pub tokens: Option<LazyTokenStream>,
}
impl Pat {
/// Attempt reparsing the pattern as a type.
/// This is intended for use by diagnostics.
pub fn to_ty(&self) -> Option<P<Ty>> {
let kind = match &self.kind {
// In a type expression `_` is an inference variable.
PatKind::Wild => TyKind::Infer,
// An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
TyKind::Path(None, Path::from_ident(*ident))
}
PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
// `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
PatKind::Ref(pat, mutbl) => {
pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
}
// A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
// when `P` can be reparsed as a type `T`.
PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
// A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
// assuming `T0` to `Tn` are all syntactically valid as types.
PatKind::Tuple(pats) => {
let mut tys = Vec::with_capacity(pats.len());
// FIXME(#48994) - could just be collected into an Option<Vec>
for pat in pats {
tys.push(pat.to_ty()?);
}
TyKind::Tup(tys)
}
_ => return None,
};
Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
}
/// Walk top-down and call `it` in each place where a pattern occurs
/// starting with the root pattern `walk` is called on. If `it` returns
/// false then we will descend no further but siblings will be processed.
pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
if !it(self) {
return;
}
match &self.kind {
// Walk into the pattern associated with `Ident` (if any).
PatKind::Ident(_, _, Some(p)) => p.walk(it),
// Walk into each field of struct.
PatKind::Struct(_, _, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
// Sequence of patterns.
PatKind::TupleStruct(_, _, s)
| PatKind::Tuple(s)
| PatKind::Slice(s)
| PatKind::Or(s) => s.iter().for_each(|p| p.walk(it)),
// Trivial wrappers over inner patterns.
PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
// These patterns do not contain subpatterns, skip.
PatKind::Wild
| PatKind::Rest
| PatKind::Lit(_)
| PatKind::Range(..)
| PatKind::Ident(..)
| PatKind::Path(..)
| PatKind::MacCall(_) => {}
}
}
/// Is this a `..` pattern?
pub fn is_rest(&self) -> bool {
matches!(self.kind, PatKind::Rest)
}
}
/// A single field in a struct pattern.
///
/// Patterns like the fields of `Foo { x, ref y, ref mut z }`
/// are treated the same as `x: x, y: ref y, z: ref mut z`,
/// except when `is_shorthand` is true.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct PatField {
/// The identifier for the field.
pub ident: Ident,
/// The pattern the field is destructured to.
pub pat: P<Pat>,
pub is_shorthand: bool,
pub attrs: AttrVec,
pub id: NodeId,
pub span: Span,
pub is_placeholder: bool,
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
pub enum BindingMode {
ByRef(Mutability),
ByValue(Mutability),
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum RangeEnd {
/// `..=` or `...`
Included(RangeSyntax),
/// `..`
Excluded,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum RangeSyntax {
/// `...`
DotDotDot,
/// `..=`
DotDotEq,
}
/// All the different flavors of pattern that Rust recognizes.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum PatKind {
/// Represents a wildcard pattern (`_`).
Wild,
/// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
/// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
/// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
/// during name resolution.
Ident(BindingMode, Ident, Option<P<Pat>>),
/// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
/// The `bool` is `true` in the presence of a `..`.
Struct(Option<QSelf>, Path, Vec<PatField>, /* recovered */ bool),
/// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
TupleStruct(Option<QSelf>, Path, Vec<P<Pat>>),
/// An or-pattern `A | B | C`.
/// Invariant: `pats.len() >= 2`.
Or(Vec<P<Pat>>),
/// A possibly qualified path pattern.
/// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
/// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
/// only legally refer to associated constants.
Path(Option<QSelf>, Path),
/// A tuple pattern (`(a, b)`).
Tuple(Vec<P<Pat>>),
/// A `box` pattern.
Box(P<Pat>),
/// A reference pattern (e.g., `&mut (a, b)`).
Ref(P<Pat>, Mutability),
/// A literal.
Lit(P<Expr>),
/// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
/// A slice pattern `[a, b, c]`.
Slice(Vec<P<Pat>>),
/// A rest pattern `..`.
///
/// Syntactically it is valid anywhere.
///
/// Semantically however, it only has meaning immediately inside:
/// - a slice pattern: `[a, .., b]`,
/// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
/// - a tuple pattern: `(a, .., b)`,
/// - a tuple struct/variant pattern: `$path(a, .., b)`.
///
/// In all of these cases, an additional restriction applies,
/// only one rest pattern may occur in the pattern sequences.
Rest,
/// Parentheses in patterns used for grouping (i.e., `(PAT)`).
Paren(P<Pat>),
/// A macro pattern; pre-expansion.
MacCall(MacCall),
}
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
#[derive(HashStable_Generic, Encodable, Decodable)]
pub enum Mutability {
Mut,
Not,
}
impl Mutability {
pub fn invert(self) -> Self {
match self {
Mutability::Mut => Mutability::Not,
Mutability::Not => Mutability::Mut,
}
}
pub fn prefix_str(&self) -> &'static str {
match self {
Mutability::Mut => "mut ",
Mutability::Not => "",
}
}
}
/// The kind of borrow in an `AddrOf` expression,
/// e.g., `&place` or `&raw const place`.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
#[derive(Encodable, Decodable, HashStable_Generic)]
pub enum BorrowKind {
/// A normal borrow, `&$expr` or `&mut $expr`.
/// The resulting type is either `&'a T` or `&'a mut T`
/// where `T = typeof($expr)` and `'a` is some lifetime.
Ref,
/// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
/// The resulting type is either `*const T` or `*mut T`
/// where `T = typeof($expr)`.
Raw,
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
pub enum BinOpKind {
/// The `+` operator (addition)
Add,
/// The `-` operator (subtraction)
Sub,
/// The `*` operator (multiplication)
Mul,
/// The `/` operator (division)
Div,
/// The `%` operator (modulus)
Rem,
/// The `&&` operator (logical and)
And,
/// The `||` operator (logical or)
Or,
/// The `^` operator (bitwise xor)
BitXor,
/// The `&` operator (bitwise and)
BitAnd,
/// The `|` operator (bitwise or)
BitOr,
/// The `<<` operator (shift left)
Shl,
/// The `>>` operator (shift right)
Shr,
/// The `==` operator (equality)
Eq,
/// The `<` operator (less than)
Lt,
/// The `<=` operator (less than or equal to)
Le,
/// The `!=` operator (not equal to)
Ne,
/// The `>=` operator (greater than or equal to)
Ge,
/// The `>` operator (greater than)
Gt,
}
impl BinOpKind {
pub fn to_string(&self) -> &'static str {
use BinOpKind::*;
match *self {
Add => "+",
Sub => "-",
Mul => "*",
Div => "/",
Rem => "%",
And => "&&",
Or => "||",
BitXor => "^",
BitAnd => "&",
BitOr => "|",
Shl => "<<",
Shr => ">>",
Eq => "==",
Lt => "<",
Le => "<=",
Ne => "!=",
Ge => ">=",
Gt => ">",
}
}
pub fn lazy(&self) -> bool {
matches!(self, BinOpKind::And | BinOpKind::Or)
}
pub fn is_comparison(&self) -> bool {
use BinOpKind::*;
// Note for developers: please keep this as is;
// we want compilation to fail if another variant is added.
match *self {
Eq | Lt | Le | Ne | Gt | Ge => true,
And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
}
}
}
pub type BinOp = Spanned<BinOpKind>;
/// Unary operator.
///
/// Note that `&data` is not an operator, it's an `AddrOf` expression.
#[derive(Clone, Encodable, Decodable, Debug, Copy)]
pub enum UnOp {
/// The `*` operator for dereferencing
Deref,
/// The `!` operator for logical inversion
Not,
/// The `-` operator for negation
Neg,
}
impl UnOp {
pub fn to_string(op: UnOp) -> &'static str {
match op {
UnOp::Deref => "*",
UnOp::Not => "!",
UnOp::Neg => "-",
}
}
}
/// A statement
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Stmt {
pub id: NodeId,
pub kind: StmtKind,
pub span: Span,
}
impl Stmt {
pub fn tokens(&self) -> Option<&LazyTokenStream> {
match self.kind {
StmtKind::Local(ref local) => local.tokens.as_ref(),
StmtKind::Item(ref item) => item.tokens.as_ref(),
StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => expr.tokens.as_ref(),
StmtKind::Empty => None,
StmtKind::MacCall(ref mac) => mac.tokens.as_ref(),
}
}
pub fn has_trailing_semicolon(&self) -> bool {
match &self.kind {
StmtKind::Semi(_) => true,
StmtKind::MacCall(mac) => matches!(mac.style, MacStmtStyle::Semicolon),
_ => false,
}
}
/// Converts a parsed `Stmt` to a `Stmt` with
/// a trailing semicolon.
///
/// This only modifies the parsed AST struct, not the attached
/// `LazyTokenStream`. The parser is responsible for calling
/// `CreateTokenStream::add_trailing_semi` when there is actually
/// a semicolon in the tokenstream.
pub fn add_trailing_semicolon(mut self) -> Self {
self.kind = match self.kind {
StmtKind::Expr(expr) => StmtKind::Semi(expr),
StmtKind::MacCall(mac) => {
StmtKind::MacCall(mac.map(|MacCallStmt { mac, style: _, attrs, tokens }| {
MacCallStmt { mac, style: MacStmtStyle::Semicolon, attrs, tokens }
}))
}
kind => kind,
};
self
}
pub fn is_item(&self) -> bool {
matches!(self.kind, StmtKind::Item(_))
}
pub fn is_expr(&self) -> bool {
matches!(self.kind, StmtKind::Expr(_))
}
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum StmtKind {
/// A local (let) binding.
Local(P<Local>),
/// An item definition.
Item(P<Item>),
/// Expr without trailing semi-colon.
Expr(P<Expr>),
/// Expr with a trailing semi-colon.
Semi(P<Expr>),
/// Just a trailing semi-colon.
Empty,
/// Macro.
MacCall(P<MacCallStmt>),
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct MacCallStmt {
pub mac: MacCall,
pub style: MacStmtStyle,
pub attrs: AttrVec,
pub tokens: Option<LazyTokenStream>,
}
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
pub enum MacStmtStyle {
/// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
/// `foo!(...);`, `foo![...];`).
Semicolon,
/// The macro statement had braces (e.g., `foo! { ... }`).
Braces,
/// The macro statement had parentheses or brackets and no semicolon (e.g.,
/// `foo!(...)`). All of these will end up being converted into macro
/// expressions.
NoBraces,
}
/// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Local {
pub id: NodeId,
pub pat: P<Pat>,
pub ty: Option<P<Ty>>,
pub kind: LocalKind,
pub span: Span,
pub attrs: AttrVec,
pub tokens: Option<LazyTokenStream>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum LocalKind {
/// Local declaration.
/// Example: `let x;`
Decl,
/// Local declaration with an initializer.
/// Example: `let x = y;`
Init(P<Expr>),
/// Local declaration with an initializer and an `else` clause.
/// Example: `let Some(x) = y else { return };`
InitElse(P<Expr>, P<Block>),
}
impl LocalKind {
pub fn init(&self) -> Option<&Expr> {
match self {
Self::Decl => None,
Self::Init(i) | Self::InitElse(i, _) => Some(i),
}
}
pub fn init_else_opt(&self) -> Option<(&Expr, Option<&Block>)> {
match self {
Self::Decl => None,
Self::Init(init) => Some((init, None)),
Self::InitElse(init, els) => Some((init, Some(els))),
}
}
}
/// An arm of a 'match'.
///
/// E.g., `0..=10 => { println!("match!") }` as in
///
/// ```
/// match 123 {
/// 0..=10 => { println!("match!") },
/// _ => { println!("no match!") },
/// }
/// ```
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Arm {
pub attrs: AttrVec,
/// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
pub pat: P<Pat>,
/// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
pub guard: Option<P<Expr>>,
/// Match arm body.
pub body: P<Expr>,
pub span: Span,
pub id: NodeId,
pub is_placeholder: bool,
}
/// A single field in a struct expression, e.g. `x: value` and `y` in `Foo { x: value, y }`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct ExprField {
pub attrs: AttrVec,
pub id: NodeId,
pub span: Span,
pub ident: Ident,
pub expr: P<Expr>,
pub is_shorthand: bool,
pub is_placeholder: bool,
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
pub enum BlockCheckMode {
Default,
Unsafe(UnsafeSource),
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
pub enum UnsafeSource {
CompilerGenerated,
UserProvided,
}
/// A constant (expression) that's not an item or associated item,
/// but needs its own `DefId` for type-checking, const-eval, etc.
/// These are usually found nested inside types (e.g., array lengths)
/// or expressions (e.g., repeat counts), and also used to define
/// explicit discriminant values for enum variants.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct AnonConst {
pub id: NodeId,
pub value: P<Expr>,
}
/// An expression.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Expr {
pub id: NodeId,
pub kind: ExprKind,
pub span: Span,
pub attrs: AttrVec,
pub tokens: Option<LazyTokenStream>,
}
// `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
rustc_data_structures::static_assert_size!(Expr, 104);
impl Expr {
/// Returns `true` if this expression would be valid somewhere that expects a value;
/// for example, an `if` condition.
pub fn returns(&self) -> bool {
if let ExprKind::Block(ref block, _) = self.kind {
match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
// Implicit return
Some(StmtKind::Expr(_)) => true,
// Last statement is an explicit return?
Some(StmtKind::Semi(expr)) => matches!(expr.kind, ExprKind::Ret(_)),
// This is a block that doesn't end in either an implicit or explicit return.
_ => false,
}
} else {
// This is not a block, it is a value.
true
}
}
/// Is this expr either `N`, or `{ N }`.
///
/// If this is not the case, name resolution does not resolve `N` when using
/// `min_const_generics` as more complex expressions are not supported.
pub fn is_potential_trivial_const_param(&self) -> bool {
let this = if let ExprKind::Block(ref block, None) = self.kind {
if block.stmts.len() == 1 {
if let StmtKind::Expr(ref expr) = block.stmts[0].kind { expr } else { self }
} else {
self
}
} else {
self
};
if let ExprKind::Path(None, ref path) = this.kind {
if path.segments.len() == 1 && path.segments[0].args.is_none() {
return true;
}
}
false
}
pub fn to_bound(&self) -> Option<GenericBound> {
match &self.kind {
ExprKind::Path(None, path) => Some(GenericBound::Trait(
PolyTraitRef::new(Vec::new(), path.clone(), self.span),
TraitBoundModifier::None,
)),
_ => None,
}
}
pub fn peel_parens(&self) -> &Expr {
let mut expr = self;
while let ExprKind::Paren(inner) = &expr.kind {
expr = &inner;
}
expr
}
/// Attempts to reparse as `Ty` (for diagnostic purposes).
pub fn to_ty(&self) -> Option<P<Ty>> {
let kind = match &self.kind {
// Trivial conversions.
ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
}
ExprKind::Repeat(expr, expr_len) => {
expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
}
ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
ExprKind::Tup(exprs) => {
let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
TyKind::Tup(tys)
}
// If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
// then type of result is trait object.
// Otherwise we don't assume the result type.
ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
} else {
return None;
}
}
ExprKind::Underscore => TyKind::Infer,
// This expression doesn't look like a type syntactically.
_ => return None,
};
Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
}
pub fn precedence(&self) -> ExprPrecedence {
match self.kind {
ExprKind::Box(_) => ExprPrecedence::Box,
ExprKind::Array(_) => ExprPrecedence::Array,
ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
ExprKind::Call(..) => ExprPrecedence::Call,
ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
ExprKind::Tup(_) => ExprPrecedence::Tup,
ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
ExprKind::Unary(..) => ExprPrecedence::Unary,
ExprKind::Lit(_) => ExprPrecedence::Lit,
ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
ExprKind::Let(..) => ExprPrecedence::Let,
ExprKind::If(..) => ExprPrecedence::If,
ExprKind::While(..) => ExprPrecedence::While,
ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
ExprKind::Loop(..) => ExprPrecedence::Loop,
ExprKind::Match(..) => ExprPrecedence::Match,
ExprKind::Closure(..) => ExprPrecedence::Closure,
ExprKind::Block(..) => ExprPrecedence::Block,
ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
ExprKind::Async(..) => ExprPrecedence::Async,
ExprKind::Await(..) => ExprPrecedence::Await,
ExprKind::Assign(..) => ExprPrecedence::Assign,
ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
ExprKind::Field(..) => ExprPrecedence::Field,
ExprKind::Index(..) => ExprPrecedence::Index,
ExprKind::Range(..) => ExprPrecedence::Range,
ExprKind::Underscore => ExprPrecedence::Path,
ExprKind::Path(..) => ExprPrecedence::Path,
ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
ExprKind::Break(..) => ExprPrecedence::Break,
ExprKind::Continue(..) => ExprPrecedence::Continue,
ExprKind::Ret(..) => ExprPrecedence::Ret,
ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
ExprKind::MacCall(..) => ExprPrecedence::Mac,
ExprKind::Struct(..) => ExprPrecedence::Struct,
ExprKind::Repeat(..) => ExprPrecedence::Repeat,
ExprKind::Paren(..) => ExprPrecedence::Paren,
ExprKind::Try(..) => ExprPrecedence::Try,
ExprKind::Yield(..) => ExprPrecedence::Yield,
ExprKind::Err => ExprPrecedence::Err,
}
}
pub fn take(&mut self) -> Self {
mem::replace(
self,
Expr {
id: DUMMY_NODE_ID,
kind: ExprKind::Err,
span: DUMMY_SP,
attrs: ThinVec::new(),
tokens: None,
},
)
}
}
/// Limit types of a range (inclusive or exclusive)
#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
pub enum RangeLimits {
/// Inclusive at the beginning, exclusive at the end
HalfOpen,
/// Inclusive at the beginning and end
Closed,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum StructRest {
/// `..x`.
Base(P<Expr>),
/// `..`.
Rest(Span),
/// No trailing `..` or expression.
None,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct StructExpr {
pub qself: Option<QSelf>,
pub path: Path,
pub fields: Vec<ExprField>,
pub rest: StructRest,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum ExprKind {
/// A `box x` expression.
Box(P<Expr>),
/// An array (`[a, b, c, d]`)
Array(Vec<P<Expr>>),
/// Allow anonymous constants from an inline `const` block
ConstBlock(AnonConst),
/// A function call
///
/// The first field resolves to the function itself,
/// and the second field is the list of arguments.
/// This also represents calling the constructor of
/// tuple-like ADTs such as tuple structs and enum variants.
Call(P<Expr>, Vec<P<Expr>>),
/// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
///
/// The `PathSegment` represents the method name and its generic arguments
/// (within the angle brackets).
/// The first element of the vector of an `Expr` is the expression that evaluates
/// to the object on which the method is being called on (the receiver),
/// and the remaining elements are the rest of the arguments.
/// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
/// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
/// This `Span` is the span of the function, without the dot and receiver
/// (e.g. `foo(a, b)` in `x.foo(a, b)`
MethodCall(PathSegment, Vec<P<Expr>>, Span),
/// A tuple (e.g., `(a, b, c, d)`).
Tup(Vec<P<Expr>>),
/// A binary operation (e.g., `a + b`, `a * b`).
Binary(BinOp, P<Expr>, P<Expr>),
/// A unary operation (e.g., `!x`, `*x`).
Unary(UnOp, P<Expr>),
/// A literal (e.g., `1`, `"foo"`).
Lit(Lit),
/// A cast (e.g., `foo as f64`).
Cast(P<Expr>, P<Ty>),
/// A type ascription (e.g., `42: usize`).
Type(P<Expr>, P<Ty>),
/// A `let pat = expr` expression that is only semantically allowed in the condition
/// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
///
/// `Span` represents the whole `let pat = expr` statement.
Let(P<Pat>, P<Expr>, Span),
/// An `if` block, with an optional `else` block.
///
/// `if expr { block } else { expr }`
If(P<Expr>, P<Block>, Option<P<Expr>>),
/// A while loop, with an optional label.
///
/// `'label: while expr { block }`
While(P<Expr>, P<Block>, Option<Label>),
/// A `for` loop, with an optional label.
///
/// `'label: for pat in expr { block }`
///
/// This is desugared to a combination of `loop` and `match` expressions.
ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
/// Conditionless loop (can be exited with `break`, `continue`, or `return`).
///
/// `'label: loop { block }`
Loop(P<Block>, Option<Label>),
/// A `match` block.
Match(P<Expr>, Vec<Arm>),
/// A closure (e.g., `move |a, b, c| a + b + c`).
///
/// The final span is the span of the argument block `|...|`.
Closure(CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
/// A block (`'label: { ... }`).
Block(P<Block>, Option<Label>),
/// An async block (`async move { ... }`).
///
/// The `NodeId` is the `NodeId` for the closure that results from
/// desugaring an async block, just like the NodeId field in the
/// `Async::Yes` variant. This is necessary in order to create a def for the
/// closure which can be used as a parent of any child defs. Defs
/// created during lowering cannot be made the parent of any other
/// preexisting defs.
Async(CaptureBy, NodeId, P<Block>),
/// An await expression (`my_future.await`).
Await(P<Expr>),
/// A try block (`try { ... }`).
TryBlock(P<Block>),
/// An assignment (`a = foo()`).
/// The `Span` argument is the span of the `=` token.
Assign(P<Expr>, P<Expr>, Span),
/// An assignment with an operator.
///
/// E.g., `a += 1`.
AssignOp(BinOp, P<Expr>, P<Expr>),
/// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
Field(P<Expr>, Ident),
/// An indexing operation (e.g., `foo[2]`).
Index(P<Expr>, P<Expr>),
/// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assignment).
Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
/// An underscore, used in destructuring assignment to ignore a value.
Underscore,
/// Variable reference, possibly containing `::` and/or type
/// parameters (e.g., `foo::bar::<baz>`).
///
/// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
Path(Option<QSelf>, Path),
/// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
AddrOf(BorrowKind, Mutability, P<Expr>),
/// A `break`, with an optional label to break, and an optional expression.
Break(Option<Label>, Option<P<Expr>>),
/// A `continue`, with an optional label.
Continue(Option<Label>),
/// A `return`, with an optional value to be returned.
Ret(Option<P<Expr>>),
/// Output of the `asm!()` macro.
InlineAsm(P<InlineAsm>),
/// A macro invocation; pre-expansion.
MacCall(MacCall),
/// A struct literal expression.
///
/// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
Struct(P<StructExpr>),
/// An array literal constructed from one repeated element.
///
/// E.g., `[1; 5]`. The expression is the element to be
/// repeated; the constant is the number of times to repeat it.
Repeat(P<Expr>, AnonConst),
/// No-op: used solely so we can pretty-print faithfully.
Paren(P<Expr>),
/// A try expression (`expr?`).
Try(P<Expr>),
/// A `yield`, with an optional value to be yielded.
Yield(Option<P<Expr>>),
/// Placeholder for an expression that wasn't syntactically well formed in some way.
Err,
}
/// The explicit `Self` type in a "qualified path". The actual
/// path, including the trait and the associated item, is stored
/// separately. `position` represents the index of the associated
/// item qualified with this `Self` type.
///
/// ```ignore (only-for-syntax-highlight)
/// <Vec<T> as a::b::Trait>::AssociatedItem
/// ^~~~~ ~~~~~~~~~~~~~~^
/// ty position = 3
///
/// <Vec<T>>::AssociatedItem
/// ^~~~~ ^
/// ty position = 0
/// ```
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct QSelf {
pub ty: P<Ty>,
/// The span of `a::b::Trait` in a path like `<Vec<T> as
/// a::b::Trait>::AssociatedItem`; in the case where `position ==
/// 0`, this is an empty span.
pub path_span: Span,
pub position: usize,
}
/// A capture clause used in closures and `async` blocks.
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum CaptureBy {
/// `move |x| y + x`.
Value,
/// `move` keyword was not specified.
Ref,
}
/// The movability of a generator / closure literal:
/// whether a generator contains self-references, causing it to be `!Unpin`.
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
#[derive(HashStable_Generic)]
pub enum Movability {
/// May contain self-references, `!Unpin`.
Static,
/// Must not contain self-references, `Unpin`.
Movable,
}
/// Represents a macro invocation. The `path` indicates which macro
/// is being invoked, and the `args` are arguments passed to it.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct MacCall {
pub path: Path,
pub args: P<MacArgs>,
pub prior_type_ascription: Option<(Span, bool)>,
}
impl MacCall {
pub fn span(&self) -> Span {
self.path.span.to(self.args.span().unwrap_or(self.path.span))
}
}
/// Arguments passed to an attribute or a function-like macro.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum MacArgs {
/// No arguments - `#[attr]`.
Empty,
/// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
Delimited(DelimSpan, MacDelimiter, TokenStream),
/// Arguments of a key-value attribute - `#[attr = "value"]`.
Eq(
/// Span of the `=` token.
Span,
/// "value" as a nonterminal token.
Token,
),
}
impl MacArgs {
pub fn delim(&self) -> DelimToken {
match self {
MacArgs::Delimited(_, delim, _) => delim.to_token(),
MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
}
}
pub fn span(&self) -> Option<Span> {
match self {
MacArgs::Empty => None,
MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
MacArgs::Eq(eq_span, token) => Some(eq_span.to(token.span)),
}
}
/// Tokens inside the delimiters or after `=`.
/// Proc macros see these tokens, for example.
pub fn inner_tokens(&self) -> TokenStream {
match self {
MacArgs::Empty => TokenStream::default(),
MacArgs::Delimited(.., tokens) => tokens.clone(),
MacArgs::Eq(.., token) => TokenTree::Token(token.clone()).into(),
}
}
/// Whether a macro with these arguments needs a semicolon
/// when used as a standalone item or statement.
pub fn need_semicolon(&self) -> bool {
!matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
}
}
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum MacDelimiter {
Parenthesis,
Bracket,
Brace,
}
impl MacDelimiter {
pub fn to_token(self) -> DelimToken {
match self {
MacDelimiter::Parenthesis => DelimToken::Paren,
MacDelimiter::Bracket => DelimToken::Bracket,
MacDelimiter::Brace => DelimToken::Brace,
}
}
pub fn from_token(delim: DelimToken) -> Option<MacDelimiter> {
match delim {
token::Paren => Some(MacDelimiter::Parenthesis),
token::Bracket => Some(MacDelimiter::Bracket),
token::Brace => Some(MacDelimiter::Brace),
token::NoDelim => None,
}
}
}
/// Represents a macro definition.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct MacroDef {
pub body: P<MacArgs>,
/// `true` if macro was defined with `macro_rules`.
pub macro_rules: bool,
}
#[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
#[derive(HashStable_Generic)]
pub enum StrStyle {
/// A regular string, like `"foo"`.
Cooked,
/// A raw string, like `r##"foo"##`.
///
/// The value is the number of `#` symbols used.
Raw(u8),
}
/// An AST literal.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct Lit {
/// The original literal token as written in source code.
pub token: token::Lit,
/// The "semantic" representation of the literal lowered from the original tokens.
/// Strings are unescaped, hexadecimal forms are eliminated, etc.
/// FIXME: Remove this and only create the semantic representation during lowering to HIR.
pub kind: LitKind,
pub span: Span,
}
/// Same as `Lit`, but restricted to string literals.
#[derive(Clone, Copy, Encodable, Decodable, Debug)]
pub struct StrLit {
/// The original literal token as written in source code.
pub style: StrStyle,
pub symbol: Symbol,
pub suffix: Option<Symbol>,
pub span: Span,
/// The unescaped "semantic" representation of the literal lowered from the original token.
/// FIXME: Remove this and only create the semantic representation during lowering to HIR.
pub symbol_unescaped: Symbol,
}
impl StrLit {
pub fn as_lit(&self) -> Lit {
let token_kind = match self.style {
StrStyle::Cooked => token::Str,
StrStyle::Raw(n) => token::StrRaw(n),
};
Lit {
token: token::Lit::new(token_kind, self.symbol, self.suffix),
span: self.span,
kind: LitKind::Str(self.symbol_unescaped, self.style),
}
}
}
/// Type of the integer literal based on provided suffix.
#[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
#[derive(HashStable_Generic)]
pub enum LitIntType {
/// e.g. `42_i32`.
Signed(IntTy),
/// e.g. `42_u32`.
Unsigned(UintTy),
/// e.g. `42`.
Unsuffixed,
}
/// Type of the float literal based on provided suffix.
#[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
#[derive(HashStable_Generic)]
pub enum LitFloatType {
/// A float literal with a suffix (`1f32` or `1E10f32`).
Suffixed(FloatTy),
/// A float literal without a suffix (`1.0 or 1.0E10`).
Unsuffixed,
}
/// Literal kind.
///
/// E.g., `"foo"`, `42`, `12.34`, or `bool`.
#[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
pub enum LitKind {
/// A string literal (`"foo"`).
Str(Symbol, StrStyle),
/// A byte string (`b"foo"`).
ByteStr(Lrc<[u8]>),
/// A byte char (`b'f'`).
Byte(u8),
/// A character literal (`'a'`).
Char(char),
/// An integer literal (`1`).
Int(u128, LitIntType),
/// A float literal (`1f64` or `1E10f64`).
Float(Symbol, LitFloatType),
/// A boolean literal.
Bool(bool),
/// Placeholder for a literal that wasn't well-formed in some way.
Err(Symbol),
}
impl LitKind {
/// Returns `true` if this literal is a string.
pub fn is_str(&self) -> bool {
matches!(self, LitKind::Str(..))
}
/// Returns `true` if this literal is byte literal string.
pub fn is_bytestr(&self) -> bool {
matches!(self, LitKind::ByteStr(_))
}
/// Returns `true` if this is a numeric literal.
pub fn is_numeric(&self) -> bool {
matches!(self, LitKind::Int(..) | LitKind::Float(..))
}
/// Returns `true` if this literal has no suffix.
/// Note: this will return true for literals with prefixes such as raw strings and byte strings.
pub fn is_unsuffixed(&self) -> bool {
!self.is_suffixed()
}
/// Returns `true` if this literal has a suffix.
pub fn is_suffixed(&self) -> bool {
match *self {
// suffixed variants
LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
| LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
// unsuffixed variants
LitKind::Str(..)
| LitKind::ByteStr(..)
| LitKind::Byte(..)
| LitKind::Char(..)
| LitKind::Int(_, LitIntType::Unsuffixed)
| LitKind::Float(_, LitFloatType::Unsuffixed)
| LitKind::Bool(..)
| LitKind::Err(..) => false,
}
}
}
// N.B., If you change this, you'll probably want to change the corresponding
// type structure in `middle/ty.rs` as well.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct MutTy {
pub ty: P<Ty>,
pub mutbl: Mutability,
}
/// Represents a function's signature in a trait declaration,
/// trait implementation, or free function.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct FnSig {
pub header: FnHeader,
pub decl: P<FnDecl>,
pub span: Span,
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
#[derive(Encodable, Decodable, HashStable_Generic)]
pub enum FloatTy {
F32,
F64,
}
impl FloatTy {
pub fn name_str(self) -> &'static str {
match self {
FloatTy::F32 => "f32",
FloatTy::F64 => "f64",
}
}
pub fn name(self) -> Symbol {
match self {
FloatTy::F32 => sym::f32,
FloatTy::F64 => sym::f64,
}
}
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
#[derive(Encodable, Decodable, HashStable_Generic)]
pub enum IntTy {
Isize,
I8,
I16,
I32,
I64,
I128,
}
impl IntTy {
pub fn name_str(&self) -> &'static str {
match *self {
IntTy::Isize => "isize",
IntTy::I8 => "i8",
IntTy::I16 => "i16",
IntTy::I32 => "i32",
IntTy::I64 => "i64",
IntTy::I128 => "i128",
}
}
pub fn name(&self) -> Symbol {
match *self {
IntTy::Isize => sym::isize,
IntTy::I8 => sym::i8,
IntTy::I16 => sym::i16,
IntTy::I32 => sym::i32,
IntTy::I64 => sym::i64,
IntTy::I128 => sym::i128,
}
}
}
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
#[derive(Encodable, Decodable, HashStable_Generic)]
pub enum UintTy {
Usize,
U8,
U16,
U32,
U64,
U128,
}
impl UintTy {
pub fn name_str(&self) -> &'static str {
match *self {
UintTy::Usize => "usize",
UintTy::U8 => "u8",
UintTy::U16 => "u16",
UintTy::U32 => "u32",
UintTy::U64 => "u64",
UintTy::U128 => "u128",
}
}
pub fn name(&self) -> Symbol {
match *self {
UintTy::Usize => sym::usize,
UintTy::U8 => sym::u8,
UintTy::U16 => sym::u16,
UintTy::U32 => sym::u32,
UintTy::U64 => sym::u64,
UintTy::U128 => sym::u128,
}
}
}
/// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
/// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct AssocConstraint {
pub id: NodeId,
pub ident: Ident,
pub gen_args: Option<GenericArgs>,
pub kind: AssocConstraintKind,
pub span: Span,
}
/// The kinds of an `AssocConstraint`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum Term {
Ty(P<Ty>),
Const(AnonConst),
}
impl From<P<Ty>> for Term {
fn from(v: P<Ty>) -> Self {
Term::Ty(v)
}
}
impl From<AnonConst> for Term {
fn from(v: AnonConst) -> Self {
Term::Const(v)
}
}
/// The kinds of an `AssocConstraint`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum AssocConstraintKind {
/// E.g., `A = Bar`, `A = 3` in `Foo<A = Bar>` where A is an associated type.
Equality { term: Term },
/// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
Bound { bounds: GenericBounds },
}
#[derive(Encodable, Decodable, Debug)]
pub struct Ty {
pub id: NodeId,
pub kind: TyKind,
pub span: Span,
pub tokens: Option<LazyTokenStream>,
}
impl Clone for Ty {
fn clone(&self) -> Self {
ensure_sufficient_stack(|| Self {
id: self.id,
kind: self.kind.clone(),
span: self.span,
tokens: self.tokens.clone(),
})
}
}
impl Ty {
pub fn peel_refs(&self) -> &Self {
let mut final_ty = self;
while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
final_ty = &ty;
}
final_ty
}
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct BareFnTy {
pub unsafety: Unsafe,
pub ext: Extern,
pub generic_params: Vec<GenericParam>,
pub decl: P<FnDecl>,
}
/// The various kinds of type recognized by the compiler.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum TyKind {
/// A variable-length slice (`[T]`).
Slice(P<Ty>),
/// A fixed length array (`[T; n]`).
Array(P<Ty>, AnonConst),
/// A raw pointer (`*const T` or `*mut T`).
Ptr(MutTy),
/// A reference (`&'a T` or `&'a mut T`).
Rptr(Option<Lifetime>, MutTy),
/// A bare function (e.g., `fn(usize) -> bool`).
BareFn(P<BareFnTy>),
/// The never type (`!`).
Never,
/// A tuple (`(A, B, C, D,...)`).
Tup(Vec<P<Ty>>),
/// A path (`module::module::...::Type`), optionally
/// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
///
/// Type parameters are stored in the `Path` itself.
Path(Option<QSelf>, Path),
/// A trait object type `Bound1 + Bound2 + Bound3`
/// where `Bound` is a trait or a lifetime.
TraitObject(GenericBounds, TraitObjectSyntax),
/// An `impl Bound1 + Bound2 + Bound3` type
/// where `Bound` is a trait or a lifetime.
///
/// The `NodeId` exists to prevent lowering from having to
/// generate `NodeId`s on the fly, which would complicate
/// the generation of opaque `type Foo = impl Trait` items significantly.
ImplTrait(NodeId, GenericBounds),
/// No-op; kept solely so that we can pretty-print faithfully.
Paren(P<Ty>),
/// Unused for now.
Typeof(AnonConst),
/// This means the type should be inferred instead of it having been
/// specified. This can appear anywhere in a type.
Infer,
/// Inferred type of a `self` or `&self` argument in a method.
ImplicitSelf,
/// A macro in the type position.
MacCall(MacCall),
/// Placeholder for a kind that has failed to be defined.
Err,
/// Placeholder for a `va_list`.
CVarArgs,
}
impl TyKind {
pub fn is_implicit_self(&self) -> bool {
matches!(self, TyKind::ImplicitSelf)
}
pub fn is_unit(&self) -> bool {
matches!(self, TyKind::Tup(tys) if tys.is_empty())
}
}
/// Syntax used to declare a trait object.
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum TraitObjectSyntax {
Dyn,
None,
}
/// Inline assembly operand explicit register or register class.
///
/// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
#[derive(Clone, Copy, Encodable, Decodable, Debug)]
pub enum InlineAsmRegOrRegClass {
Reg(Symbol),
RegClass(Symbol),
}
bitflags::bitflags! {
#[derive(Encodable, Decodable, HashStable_Generic)]
pub struct InlineAsmOptions: u16 {
const PURE = 1 << 0;
const NOMEM = 1 << 1;
const READONLY = 1 << 2;
const PRESERVES_FLAGS = 1 << 3;
const NORETURN = 1 << 4;
const NOSTACK = 1 << 5;
const ATT_SYNTAX = 1 << 6;
const RAW = 1 << 7;
const MAY_UNWIND = 1 << 8;
}
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
pub enum InlineAsmTemplatePiece {
String(String),
Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
}
impl fmt::Display for InlineAsmTemplatePiece {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::String(s) => {
for c in s.chars() {
match c {
'{' => f.write_str("{{")?,
'}' => f.write_str("}}")?,
_ => c.fmt(f)?,
}
}
Ok(())
}
Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
write!(f, "{{{}:{}}}", operand_idx, modifier)
}
Self::Placeholder { operand_idx, modifier: None, .. } => {
write!(f, "{{{}}}", operand_idx)
}
}
}
}
impl InlineAsmTemplatePiece {
/// Rebuilds the asm template string from its pieces.
pub fn to_string(s: &[Self]) -> String {
use fmt::Write;
let mut out = String::new();
for p in s.iter() {
let _ = write!(out, "{}", p);
}
out
}
}
/// Inline assembly symbol operands get their own AST node that is somewhat
/// similar to `AnonConst`.
///
/// The main difference is that we specifically don't assign it `DefId` in
/// `DefCollector`. Instead this is deferred until AST lowering where we
/// lower it to an `AnonConst` (for functions) or a `Path` (for statics)
/// depending on what the path resolves to.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct InlineAsmSym {
pub id: NodeId,
pub qself: Option<QSelf>,
pub path: Path,
}
/// Inline assembly operand.
///
/// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum InlineAsmOperand {
In {
reg: InlineAsmRegOrRegClass,
expr: P<Expr>,
},
Out {
reg: InlineAsmRegOrRegClass,
late: bool,
expr: Option<P<Expr>>,
},
InOut {
reg: InlineAsmRegOrRegClass,
late: bool,
expr: P<Expr>,
},
SplitInOut {
reg: InlineAsmRegOrRegClass,
late: bool,
in_expr: P<Expr>,
out_expr: Option<P<Expr>>,
},
Const {
anon_const: AnonConst,
},
Sym {
sym: InlineAsmSym,
},
}
/// Inline assembly.
///
/// E.g., `asm!("NOP");`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct InlineAsm {
pub template: Vec<InlineAsmTemplatePiece>,
pub template_strs: Box<[(Symbol, Option<Symbol>, Span)]>,
pub operands: Vec<(InlineAsmOperand, Span)>,
pub clobber_abis: Vec<(Symbol, Span)>,
pub options: InlineAsmOptions,
pub line_spans: Vec<Span>,
}
/// A parameter in a function header.
///
/// E.g., `bar: usize` as in `fn foo(bar: usize)`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Param {
pub attrs: AttrVec,
pub ty: P<Ty>,
pub pat: P<Pat>,
pub id: NodeId,
pub span: Span,
pub is_placeholder: bool,
}
/// Alternative representation for `Arg`s describing `self` parameter of methods.
///
/// E.g., `&mut self` as in `fn foo(&mut self)`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum SelfKind {
/// `self`, `mut self`
Value(Mutability),
/// `&'lt self`, `&'lt mut self`
Region(Option<Lifetime>, Mutability),
/// `self: TYPE`, `mut self: TYPE`
Explicit(P<Ty>, Mutability),
}
pub type ExplicitSelf = Spanned<SelfKind>;
impl Param {
/// Attempts to cast parameter to `ExplicitSelf`.
pub fn to_self(&self) -> Option<ExplicitSelf> {
if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
if ident.name == kw::SelfLower {
return match self.ty.kind {
TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
}
_ => Some(respan(
self.pat.span.to(self.ty.span),
SelfKind::Explicit(self.ty.clone(), mutbl),
)),
};
}
}
None
}
/// Returns `true` if parameter is `self`.
pub fn is_self(&self) -> bool {
if let PatKind::Ident(_, ident, _) = self.pat.kind {
ident.name == kw::SelfLower
} else {
false
}
}
/// Builds a `Param` object from `ExplicitSelf`.
pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
let span = eself.span.to(eself_ident.span);
let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
let param = |mutbl, ty| Param {
attrs,
pat: P(Pat {
id: DUMMY_NODE_ID,
kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
span,
tokens: None,
}),
span,
ty,
id: DUMMY_NODE_ID,
is_placeholder: false,
};
match eself.node {
SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
SelfKind::Value(mutbl) => param(mutbl, infer_ty),
SelfKind::Region(lt, mutbl) => param(
Mutability::Not,
P(Ty {
id: DUMMY_NODE_ID,
kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
span,
tokens: None,
}),
),
}
}
}
/// A signature (not the body) of a function declaration.
///
/// E.g., `fn foo(bar: baz)`.
///
/// Please note that it's different from `FnHeader` structure
/// which contains metadata about function safety, asyncness, constness and ABI.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct FnDecl {
pub inputs: Vec<Param>,
pub output: FnRetTy,
}
impl FnDecl {
pub fn has_self(&self) -> bool {
self.inputs.get(0).map_or(false, Param::is_self)
}
pub fn c_variadic(&self) -> bool {
self.inputs.last().map_or(false, |arg| matches!(arg.ty.kind, TyKind::CVarArgs))
}
}
/// Is the trait definition an auto trait?
#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum IsAuto {
Yes,
No,
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
#[derive(HashStable_Generic)]
pub enum Unsafe {
Yes(Span),
No,
}
#[derive(Copy, Clone, Encodable, Decodable, Debug)]
pub enum Async {
Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
No,
}
impl Async {
pub fn is_async(self) -> bool {
matches!(self, Async::Yes { .. })
}
/// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
pub fn opt_return_id(self) -> Option<NodeId> {
match self {
Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
Async::No => None,
}
}
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
#[derive(HashStable_Generic)]
pub enum Const {
Yes(Span),
No,
}
/// Item defaultness.
/// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum Defaultness {
Default(Span),
Final,
}
#[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
pub enum ImplPolarity {
/// `impl Trait for Type`
Positive,
/// `impl !Trait for Type`
Negative(Span),
}
impl fmt::Debug for ImplPolarity {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
ImplPolarity::Positive => "positive".fmt(f),
ImplPolarity::Negative(_) => "negative".fmt(f),
}
}
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum FnRetTy {
/// Returns type is not specified.
///
/// Functions default to `()` and closures default to inference.
/// Span points to where return type would be inserted.
Default(Span),
/// Everything else.
Ty(P<Ty>),
}
impl FnRetTy {
pub fn span(&self) -> Span {
match *self {
FnRetTy::Default(span) => span,
FnRetTy::Ty(ref ty) => ty.span,
}
}
}
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
pub enum Inline {
Yes,
No,
}
/// Module item kind.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum ModKind {
/// Module with inlined definition `mod foo { ... }`,
/// or with definition outlined to a separate file `mod foo;` and already loaded from it.
/// The inner span is from the first token past `{` to the last token until `}`,
/// or from the first to the last token in the loaded file.
Loaded(Vec<P<Item>>, Inline, ModSpans),
/// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
Unloaded,
}
#[derive(Copy, Clone, Encodable, Decodable, Debug)]
pub struct ModSpans {
/// `inner_span` covers the body of the module; for a file module, its the whole file.
/// For an inline module, its the span inside the `{ ... }`, not including the curly braces.
pub inner_span: Span,
pub inject_use_span: Span,
}
impl Default for ModSpans {
fn default() -> ModSpans {
ModSpans { inner_span: Default::default(), inject_use_span: Default::default() }
}
}
/// Foreign module declaration.
///
/// E.g., `extern { .. }` or `extern "C" { .. }`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct ForeignMod {
/// `unsafe` keyword accepted syntactically for macro DSLs, but not
/// semantically by Rust.
pub unsafety: Unsafe,
pub abi: Option<StrLit>,
pub items: Vec<P<ForeignItem>>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct EnumDef {
pub variants: Vec<Variant>,
}
/// Enum variant.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Variant {
/// Attributes of the variant.
pub attrs: AttrVec,
/// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
pub id: NodeId,
/// Span
pub span: Span,
/// The visibility of the variant. Syntactically accepted but not semantically.
pub vis: Visibility,
/// Name of the variant.
pub ident: Ident,
/// Fields and constructor id of the variant.
pub data: VariantData,
/// Explicit discriminant, e.g., `Foo = 1`.
pub disr_expr: Option<AnonConst>,
/// Is a macro placeholder
pub is_placeholder: bool,
}
/// Part of `use` item to the right of its prefix.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum UseTreeKind {
/// `use prefix` or `use prefix as rename`
///
/// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
/// namespace.
Simple(Option<Ident>, NodeId, NodeId),
/// `use prefix::{...}`
Nested(Vec<(UseTree, NodeId)>),
/// `use prefix::*`
Glob,
}
/// A tree of paths sharing common prefixes.
/// Used in `use` items both at top-level and inside of braces in import groups.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct UseTree {
pub prefix: Path,
pub kind: UseTreeKind,
pub span: Span,
}
impl UseTree {
pub fn ident(&self) -> Ident {
match self.kind {
UseTreeKind::Simple(Some(rename), ..) => rename,
UseTreeKind::Simple(None, ..) => {
self.prefix.segments.last().expect("empty prefix in a simple import").ident
}
_ => panic!("`UseTree::ident` can only be used on a simple import"),
}
}
}
/// Distinguishes between `Attribute`s that decorate items and Attributes that
/// are contained as statements within items. These two cases need to be
/// distinguished for pretty-printing.
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
pub enum AttrStyle {
Outer,
Inner,
}
rustc_index::newtype_index! {
pub struct AttrId {
ENCODABLE = custom
DEBUG_FORMAT = "AttrId({})"
}
}
impl<S: Encoder> rustc_serialize::Encodable<S> for AttrId {
fn encode(&self, s: &mut S) -> Result<(), S::Error> {
s.emit_unit()
}
}
impl<D: Decoder> rustc_serialize::Decodable<D> for AttrId {
fn decode(_: &mut D) -> AttrId {
crate::attr::mk_attr_id()
}
}
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct AttrItem {
pub path: Path,
pub args: MacArgs,
pub tokens: Option<LazyTokenStream>,
}
/// A list of attributes.
pub type AttrVec = ThinVec<Attribute>;
/// Metadata associated with an item.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Attribute {
pub kind: AttrKind,
pub id: AttrId,
/// Denotes if the attribute decorates the following construct (outer)
/// or the construct this attribute is contained within (inner).
pub style: AttrStyle,
pub span: Span,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum AttrKind {
/// A normal attribute.
Normal(AttrItem, Option<LazyTokenStream>),
/// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
/// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
/// variant (which is much less compact and thus more expensive).
DocComment(CommentKind, Symbol),
}
/// `TraitRef`s appear in impls.
///
/// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
/// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
/// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
/// same as the impl's `NodeId`).
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct TraitRef {
pub path: Path,
pub ref_id: NodeId,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct PolyTraitRef {
/// The `'a` in `for<'a> Foo<&'a T>`.
pub bound_generic_params: Vec<GenericParam>,
/// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
pub trait_ref: TraitRef,
pub span: Span,
}
impl PolyTraitRef {
pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
PolyTraitRef {
bound_generic_params: generic_params,
trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
span,
}
}
}
#[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum CrateSugar {
/// Source is `pub(crate)`.
PubCrate,
/// Source is (just) `crate`.
JustCrate,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Visibility {
pub kind: VisibilityKind,
pub span: Span,
pub tokens: Option<LazyTokenStream>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum VisibilityKind {
Public,
Crate(CrateSugar),
Restricted { path: P<Path>, id: NodeId },
Inherited,
}
impl VisibilityKind {
pub fn is_pub(&self) -> bool {
matches!(self, VisibilityKind::Public)
}
}
/// Field definition in a struct, variant or union.
///
/// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct FieldDef {
pub attrs: AttrVec,
pub id: NodeId,
pub span: Span,
pub vis: Visibility,
pub ident: Option<Ident>,
pub ty: P<Ty>,
pub is_placeholder: bool,
}
/// Fields and constructor ids of enum variants and structs.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum VariantData {
/// Struct variant.
///
/// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
Struct(Vec<FieldDef>, bool),
/// Tuple variant.
///
/// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
Tuple(Vec<FieldDef>, NodeId),
/// Unit variant.
///
/// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
Unit(NodeId),
}
impl VariantData {
/// Return the fields of this variant.
pub fn fields(&self) -> &[FieldDef] {
match *self {
VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
_ => &[],
}
}
/// Return the `NodeId` of this variant's constructor, if it has one.
pub fn ctor_id(&self) -> Option<NodeId> {
match *self {
VariantData::Struct(..) => None,
VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
}
}
}
/// An item definition.
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Item<K = ItemKind> {
pub attrs: Vec<Attribute>,
pub id: NodeId,
pub span: Span,
pub vis: Visibility,
/// The name of the item.
/// It might be a dummy name in case of anonymous items.
pub ident: Ident,
pub kind: K,
/// Original tokens this item was parsed from. This isn't necessarily
/// available for all items, although over time more and more items should
/// have this be `Some`. Right now this is primarily used for procedural
/// macros, notably custom attributes.
///
/// Note that the tokens here do not include the outer attributes, but will
/// include inner attributes.
pub tokens: Option<LazyTokenStream>,
}
impl Item {
/// Return the span that encompasses the attributes.
pub fn span_with_attributes(&self) -> Span {
self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
}
}
impl<K: Into<ItemKind>> Item<K> {
pub fn into_item(self) -> Item {
let Item { attrs, id, span, vis, ident, kind, tokens } = self;
Item { attrs, id, span, vis, ident, kind: kind.into(), tokens }
}
}
/// `extern` qualifier on a function item or function type.
#[derive(Clone, Copy, Encodable, Decodable, Debug)]
pub enum Extern {
None,
Implicit,
Explicit(StrLit),
}
impl Extern {
pub fn from_abi(abi: Option<StrLit>) -> Extern {
abi.map_or(Extern::Implicit, Extern::Explicit)
}
}
/// A function header.
///
/// All the information between the visibility and the name of the function is
/// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
#[derive(Clone, Copy, Encodable, Decodable, Debug)]
pub struct FnHeader {
pub unsafety: Unsafe,
pub asyncness: Async,
pub constness: Const,
pub ext: Extern,
}
impl FnHeader {
/// Does this function header have any qualifiers or is it empty?
pub fn has_qualifiers(&self) -> bool {
let Self { unsafety, asyncness, constness, ext } = self;
matches!(unsafety, Unsafe::Yes(_))
|| asyncness.is_async()
|| matches!(constness, Const::Yes(_))
|| !matches!(ext, Extern::None)
}
}
impl Default for FnHeader {
fn default() -> FnHeader {
FnHeader {
unsafety: Unsafe::No,
asyncness: Async::No,
constness: Const::No,
ext: Extern::None,
}
}
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Trait {
pub unsafety: Unsafe,
pub is_auto: IsAuto,
pub generics: Generics,
pub bounds: GenericBounds,
pub items: Vec<P<AssocItem>>,
}
/// The location of a where clause on a `TyAlias` (`Span`) and whether there was
/// a `where` keyword (`bool`). This is split out from `WhereClause`, since there
/// are two locations for where clause on type aliases, but their predicates
/// are concatenated together.
///
/// Take this example:
/// ```ignore (only-for-syntax-highlight)
/// trait Foo {
/// type Assoc<'a, 'b> where Self: 'a, Self: 'b;
/// }
/// impl Foo for () {
/// type Assoc<'a, 'b> where Self: 'a = () where Self: 'b;
/// // ^^^^^^^^^^^^^^ first where clause
/// // ^^^^^^^^^^^^^^ second where clause
/// }
/// ```
///
/// If there is no where clause, then this is `false` with `DUMMY_SP`.
#[derive(Copy, Clone, Encodable, Decodable, Debug, Default)]
pub struct TyAliasWhereClause(pub bool, pub Span);
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct TyAlias {
pub defaultness: Defaultness,
pub generics: Generics,
/// The span information for the two where clauses (before equals, after equals)
pub where_clauses: (TyAliasWhereClause, TyAliasWhereClause),
/// The index in `generics.where_clause.predicates` that would split into
/// predicates from the where clause before the equals and the predicates
/// from the where clause after the equals
pub where_predicates_split: usize,
pub bounds: GenericBounds,
pub ty: Option<P<Ty>>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Impl {
pub defaultness: Defaultness,
pub unsafety: Unsafe,
pub generics: Generics,
pub constness: Const,
pub polarity: ImplPolarity,
/// The trait being implemented, if any.
pub of_trait: Option<TraitRef>,
pub self_ty: P<Ty>,
pub items: Vec<P<AssocItem>>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Fn {
pub defaultness: Defaultness,
pub generics: Generics,
pub sig: FnSig,
pub body: Option<P<Block>>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum ItemKind {
/// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
///
/// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
ExternCrate(Option<Symbol>),
/// A use declaration item (`use`).
///
/// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
Use(UseTree),
/// A static item (`static`).
///
/// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
Static(P<Ty>, Mutability, Option<P<Expr>>),
/// A constant item (`const`).
///
/// E.g., `const FOO: i32 = 42;`.
Const(Defaultness, P<Ty>, Option<P<Expr>>),
/// A function declaration (`fn`).
///
/// E.g., `fn foo(bar: usize) -> usize { .. }`.
Fn(Box<Fn>),
/// A module declaration (`mod`).
///
/// E.g., `mod foo;` or `mod foo { .. }`.
/// `unsafe` keyword on modules is accepted syntactically for macro DSLs, but not
/// semantically by Rust.
Mod(Unsafe, ModKind),
/// An external module (`extern`).
///
/// E.g., `extern {}` or `extern "C" {}`.
ForeignMod(ForeignMod),
/// Module-level inline assembly (from `global_asm!()`).
GlobalAsm(Box<InlineAsm>),
/// A type alias (`type`).
///
/// E.g., `type Foo = Bar<u8>;`.
TyAlias(Box<TyAlias>),
/// An enum definition (`enum`).
///
/// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
Enum(EnumDef, Generics),
/// A struct definition (`struct`).
///
/// E.g., `struct Foo<A> { x: A }`.
Struct(VariantData, Generics),
/// A union definition (`union`).
///
/// E.g., `union Foo<A, B> { x: A, y: B }`.
Union(VariantData, Generics),
/// A trait declaration (`trait`).
///
/// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
Trait(Box<Trait>),
/// Trait alias
///
/// E.g., `trait Foo = Bar + Quux;`.
TraitAlias(Generics, GenericBounds),
/// An implementation.
///
/// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
Impl(Box<Impl>),
/// A macro invocation.
///
/// E.g., `foo!(..)`.
MacCall(MacCall),
/// A macro definition.
MacroDef(MacroDef),
}
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
rustc_data_structures::static_assert_size!(ItemKind, 112);
impl ItemKind {
pub fn article(&self) -> &str {
use ItemKind::*;
match self {
Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
| Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
}
}
pub fn descr(&self) -> &str {
match self {
ItemKind::ExternCrate(..) => "extern crate",
ItemKind::Use(..) => "`use` import",
ItemKind::Static(..) => "static item",
ItemKind::Const(..) => "constant item",
ItemKind::Fn(..) => "function",
ItemKind::Mod(..) => "module",
ItemKind::ForeignMod(..) => "extern block",
ItemKind::GlobalAsm(..) => "global asm item",
ItemKind::TyAlias(..) => "type alias",
ItemKind::Enum(..) => "enum",
ItemKind::Struct(..) => "struct",
ItemKind::Union(..) => "union",
ItemKind::Trait(..) => "trait",
ItemKind::TraitAlias(..) => "trait alias",
ItemKind::MacCall(..) => "item macro invocation",
ItemKind::MacroDef(..) => "macro definition",
ItemKind::Impl { .. } => "implementation",
}
}
pub fn generics(&self) -> Option<&Generics> {
match self {
Self::Fn(box Fn { generics, .. })
| Self::TyAlias(box TyAlias { generics, .. })
| Self::Enum(_, generics)
| Self::Struct(_, generics)
| Self::Union(_, generics)
| Self::Trait(box Trait { generics, .. })
| Self::TraitAlias(generics, _)
| Self::Impl(box Impl { generics, .. }) => Some(generics),
_ => None,
}
}
}
/// Represents associated items.
/// These include items in `impl` and `trait` definitions.
pub type AssocItem = Item<AssocItemKind>;
/// Represents associated item kinds.
///
/// The term "provided" in the variants below refers to the item having a default
/// definition / body. Meanwhile, a "required" item lacks a definition / body.
/// In an implementation, all items must be provided.
/// The `Option`s below denote the bodies, where `Some(_)`
/// means "provided" and conversely `None` means "required".
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum AssocItemKind {
/// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
/// If `def` is parsed, then the constant is provided, and otherwise required.
Const(Defaultness, P<Ty>, Option<P<Expr>>),
/// An associated function.
Fn(Box<Fn>),
/// An associated type.
TyAlias(Box<TyAlias>),
/// A macro expanding to associated items.
MacCall(MacCall),
}
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
rustc_data_structures::static_assert_size!(AssocItemKind, 72);
impl AssocItemKind {
pub fn defaultness(&self) -> Defaultness {
match *self {
Self::Const(defaultness, ..)
| Self::Fn(box Fn { defaultness, .. })
| Self::TyAlias(box TyAlias { defaultness, .. }) => defaultness,
Self::MacCall(..) => Defaultness::Final,
}
}
}
impl From<AssocItemKind> for ItemKind {
fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
match assoc_item_kind {
AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
AssocItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
}
}
}
impl TryFrom<ItemKind> for AssocItemKind {
type Error = ItemKind;
fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
Ok(match item_kind {
ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
ItemKind::TyAlias(ty_alias_kind) => AssocItemKind::TyAlias(ty_alias_kind),
ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
_ => return Err(item_kind),
})
}
}
/// An item in `extern` block.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum ForeignItemKind {
/// A foreign static item (`static FOO: u8`).
Static(P<Ty>, Mutability, Option<P<Expr>>),
/// An foreign function.
Fn(Box<Fn>),
/// An foreign type.
TyAlias(Box<TyAlias>),
/// A macro expanding to foreign items.
MacCall(MacCall),
}
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
rustc_data_structures::static_assert_size!(ForeignItemKind, 72);
impl From<ForeignItemKind> for ItemKind {
fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
match foreign_item_kind {
ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
}
}
}
impl TryFrom<ItemKind> for ForeignItemKind {
type Error = ItemKind;
fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
Ok(match item_kind {
ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
_ => return Err(item_kind),
})
}
}
pub type ForeignItem = Item<ForeignItemKind>;
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