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rust/rust/8ae423e5e8db47b8233ad657b8d84247f94de179/./compiler/rustc_ast/src/ast.rs
blob: 024624cd3bb8789ff8de551dba6e3608950e2959 [file]
//! 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.
//! - [`MetaItemLit`] and [`LitKind`]: Literal expressions.
//! - [`MacroDef`], [`MacStmtStyle`], [`MacCall`]: Macro definition and invocation.
//! - [`Attribute`]: Metadata associated with item.
//! - [`UnOp`], [`BinOp`], and [`BinOpKind`]: Unary and binary operators.
use std::borrow::{Borrow, Cow};
use std::{cmp, fmt};
pub use GenericArgs::*;
pub use UnsafeSource::*;
pub use rustc_ast_ir::{FloatTy, IntTy, Movability, Mutability, Pinnedness, UintTy};
use rustc_data_structures::packed::Pu128;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_data_structures::tagged_ptr::Tag;
use rustc_macros::{Decodable, Encodable, HashStable_Generic, Walkable};
pub use rustc_span::AttrId;
use rustc_span::{
ByteSymbol, DUMMY_SP, ErrorGuaranteed, Ident, Span, Spanned, Symbol, kw, respan, sym,
};
use thin_vec::{ThinVec, thin_vec};
use crate::attr::data_structures::CfgEntry;
pub use crate::format::*;
use crate::token::{self, CommentKind, Delimiter};
use crate::tokenstream::{DelimSpan, LazyAttrTokenStream, TokenStream};
use crate::util::parser::{ExprPrecedence, Fixity};
use crate::visit::{AssocCtxt, BoundKind, LifetimeCtxt};
/// 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, Walkable)]
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, PartialEq, Eq, Hash, Walkable)]
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, Walkable)]
pub struct Path {
pub span: Span,
/// The segments in the path: the things separated by `::`.
/// Global paths begin with `kw::PathRoot`.
pub segments: ThinVec<PathSegment>,
pub tokens: Option<LazyAttrTokenStream>,
}
// Succeeds if the path has a single segment that is arg-free and matches the given symbol.
impl PartialEq<Symbol> for Path {
#[inline]
fn eq(&self, name: &Symbol) -> bool {
if let [segment] = self.segments.as_ref()
&& segment == name
{
true
} else {
false
}
}
}
// Succeeds if the path has segments that are arg-free and match the given symbols.
impl PartialEq<&[Symbol]> for Path {
#[inline]
fn eq(&self, names: &&[Symbol]) -> bool {
self.segments.iter().eq(*names)
}
}
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: thin_vec![PathSegment::from_ident(ident)], span: ident.span, tokens: None }
}
pub fn is_global(&self) -> bool {
self.segments.first().is_some_and(|segment| segment.ident.name == kw::PathRoot)
}
/// Check if this path is potentially a trivial const arg, i.e., one that can _potentially_
/// be represented without an anon const in the HIR.
///
/// Returns true iff the path has exactly one segment, and it has no generic args
/// (i.e., it is _potentially_ a const parameter).
#[tracing::instrument(level = "debug", ret)]
pub fn is_potential_trivial_const_arg(&self) -> bool {
self.segments.len() == 1 && self.segments.iter().all(|seg| seg.args.is_none())
}
}
/// Joins multiple symbols with "::" into a path, e.g. "a::b::c". If the first
/// segment is `kw::PathRoot` it will be printed as empty, e.g. "::b::c".
///
/// The generics on the `path` argument mean it can accept many forms, such as:
/// - `&[Symbol]`
/// - `Vec<Symbol>`
/// - `Vec<&Symbol>`
/// - `impl Iterator<Item = Symbol>`
/// - `impl Iterator<Item = &Symbol>`
///
/// Panics if `path` is empty or a segment after the first is `kw::PathRoot`.
pub fn join_path_syms(path: impl IntoIterator<Item = impl Borrow<Symbol>>) -> String {
// This is a guess at the needed capacity that works well in practice. It is slightly faster
// than (a) starting with an empty string, or (b) computing the exact capacity required.
// `8` works well because it's about the right size and jemalloc's size classes are all
// multiples of 8.
let mut iter = path.into_iter();
let len_hint = iter.size_hint().1.unwrap_or(1);
let mut s = String::with_capacity(len_hint * 8);
let first_sym = *iter.next().unwrap().borrow();
if first_sym != kw::PathRoot {
s.push_str(first_sym.as_str());
}
for sym in iter {
let sym = *sym.borrow();
debug_assert_ne!(sym, kw::PathRoot);
s.push_str("::");
s.push_str(sym.as_str());
}
s
}
/// Like `join_path_syms`, but for `Ident`s. This function is necessary because
/// `Ident::to_string` does more than just print the symbol in the `name` field.
pub fn join_path_idents(path: impl IntoIterator<Item = impl Borrow<Ident>>) -> String {
let mut iter = path.into_iter();
let len_hint = iter.size_hint().1.unwrap_or(1);
let mut s = String::with_capacity(len_hint * 8);
let first_ident = *iter.next().unwrap().borrow();
if first_ident.name != kw::PathRoot {
s.push_str(&first_ident.to_string());
}
for ident in iter {
let ident = *ident.borrow();
debug_assert_ne!(ident.name, kw::PathRoot);
s.push_str("::");
s.push_str(&ident.to_string());
}
s
}
/// 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, Walkable)]
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<Box<GenericArgs>>,
}
// Succeeds if the path segment is arg-free and matches the given symbol.
impl PartialEq<Symbol> for PathSegment {
#[inline]
fn eq(&self, name: &Symbol) -> bool {
self.args.is_none() && self.ident.name == *name
}
}
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 generic arguments and associated item constraints 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, Walkable)]
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),
/// `(..)` in return type notation.
ParenthesizedElided(Span),
}
impl GenericArgs {
pub fn is_angle_bracketed(&self) -> bool {
matches!(self, AngleBracketed(..))
}
pub fn span(&self) -> Span {
match self {
AngleBracketed(data) => data.span,
Parenthesized(data) => data.span,
ParenthesizedElided(span) => *span,
}
}
}
/// Concrete argument in the sequence of generic args.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum GenericArg {
/// `'a` in `Foo<'a>`.
Lifetime(#[visitable(extra = LifetimeCtxt::GenericArg)] Lifetime),
/// `Bar` in `Foo<Bar>`.
Type(Box<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, Walkable)]
pub struct AngleBracketedArgs {
/// The overall span.
pub span: Span,
/// The comma separated parts in the `<...>`.
pub args: ThinVec<AngleBracketedArg>,
}
/// Either an argument for a generic parameter or a constraint on an associated item.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum AngleBracketedArg {
/// A generic argument for a generic parameter.
Arg(GenericArg),
/// A constraint on an associated item.
Constraint(AssocItemConstraint),
}
impl AngleBracketedArg {
pub fn span(&self) -> Span {
match self {
AngleBracketedArg::Arg(arg) => arg.span(),
AngleBracketedArg::Constraint(constraint) => constraint.span,
}
}
}
impl From<AngleBracketedArgs> for Box<GenericArgs> {
fn from(val: AngleBracketedArgs) -> Self {
Box::new(GenericArgs::AngleBracketed(val))
}
}
impl From<ParenthesizedArgs> for Box<GenericArgs> {
fn from(val: ParenthesizedArgs) -> Self {
Box::new(GenericArgs::Parenthesized(val))
}
}
/// A path like `Foo(A, B) -> C`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct ParenthesizedArgs {
/// ```text
/// Foo(A, B) -> C
/// ^^^^^^^^^^^^^^
/// ```
pub span: Span,
/// `(A, B)`
pub inputs: ThinVec<Box<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::{CRATE_NODE_ID, DUMMY_NODE_ID, NodeId};
/// Modifiers on a trait bound like `[const]`, `?` and `!`.
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, Walkable)]
pub struct TraitBoundModifiers {
pub constness: BoundConstness,
pub asyncness: BoundAsyncness,
pub polarity: BoundPolarity,
}
impl TraitBoundModifiers {
pub const NONE: Self = Self {
constness: BoundConstness::Never,
asyncness: BoundAsyncness::Normal,
polarity: BoundPolarity::Positive,
};
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum GenericBound {
Trait(PolyTraitRef),
Outlives(#[visitable(extra = LifetimeCtxt::Bound)] Lifetime),
/// Precise capturing syntax: `impl Sized + use<'a>`
Use(ThinVec<PreciseCapturingArg>, Span),
}
impl GenericBound {
pub fn span(&self) -> Span {
match self {
GenericBound::Trait(t, ..) => t.span,
GenericBound::Outlives(l) => l.ident.span,
GenericBound::Use(_, span) => *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, PartialEq, Eq, PartialOrd, Ord)]
pub enum ParamKindOrd {
Lifetime,
TypeOrConst,
}
impl fmt::Display for ParamKindOrd {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
ParamKindOrd::Lifetime => "lifetime".fmt(f),
ParamKindOrd::TypeOrConst => "type and const".fmt(f),
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum GenericParamKind {
/// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
Lifetime,
Type {
default: Option<Box<Ty>>,
},
Const {
ty: Box<Ty>,
/// Span of the whole parameter definition, including default.
span: Span,
/// Optional default value for the const generic param.
default: Option<AnonConst>,
},
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct GenericParam {
pub id: NodeId,
pub ident: Ident,
pub attrs: AttrVec,
#[visitable(extra = BoundKind::Bound)]
pub bounds: GenericBounds,
pub is_placeholder: bool,
pub kind: GenericParamKind,
pub colon_span: Option<Span>,
}
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 { span, .. } => *span,
}
}
}
/// Represents lifetime, type and const parameters attached to a declaration of
/// a function, enum, trait, etc.
#[derive(Clone, Encodable, Decodable, Debug, Default, Walkable)]
pub struct Generics {
pub params: ThinVec<GenericParam>,
pub where_clause: WhereClause,
pub span: Span,
}
/// A where-clause in a definition.
#[derive(Clone, Encodable, Decodable, Debug, Default, Walkable)]
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 pretty-print accurately and provide correct suggestion diagnostics.
pub has_where_token: bool,
pub predicates: ThinVec<WherePredicate>,
pub span: Span,
}
impl WhereClause {
pub fn is_empty(&self) -> bool {
!self.has_where_token && self.predicates.is_empty()
}
}
/// A single predicate in a where-clause.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct WherePredicate {
pub attrs: AttrVec,
pub kind: WherePredicateKind,
pub id: NodeId,
pub span: Span,
pub is_placeholder: bool,
}
/// Predicate kind in where-clause.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum WherePredicateKind {
/// A type bound (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),
}
/// A type bound.
///
/// E.g., `for<'c> Foo: Send + Clone + 'c`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct WhereBoundPredicate {
/// Any generics from a `for` binding.
pub bound_generic_params: ThinVec<GenericParam>,
/// The type being bounded.
pub bounded_ty: Box<Ty>,
/// Trait and lifetime bounds (`Clone + Send + 'static`).
#[visitable(extra = BoundKind::Bound)]
pub bounds: GenericBounds,
}
/// A lifetime predicate.
///
/// E.g., `'a: 'b + 'c`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct WhereRegionPredicate {
#[visitable(extra = LifetimeCtxt::Bound)]
pub lifetime: Lifetime,
#[visitable(extra = BoundKind::Bound)]
pub bounds: GenericBounds,
}
/// An equality predicate (unsupported).
///
/// E.g., `T = int`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct WhereEqPredicate {
pub lhs_ty: Box<Ty>,
pub rhs_ty: Box<Ty>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Crate {
/// 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 attrs: AttrVec,
pub items: ThinVec<Box<Item>>,
pub spans: ModSpans,
pub is_placeholder: bool,
}
/// A semantic representation of a meta item. A meta item is a slightly
/// restricted form of an attribute -- it can only contain expressions in
/// certain leaf positions, rather than arbitrary token streams -- that is used
/// for most built-in attributes.
///
/// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct MetaItem {
pub unsafety: Safety,
pub path: Path,
pub kind: MetaItemKind,
pub span: Span,
}
/// The meta item kind, containing the data after the initial path.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum MetaItemKind {
/// Word meta item.
///
/// E.g., `#[test]`, which lacks any arguments after `test`.
Word,
/// List meta item.
///
/// E.g., `#[derive(..)]`, where the field represents the `..`.
List(ThinVec<MetaItemInner>),
/// Name value meta item.
///
/// E.g., `#[feature = "foo"]`, where the field represents the `"foo"`.
NameValue(MetaItemLit),
}
/// Values inside meta item lists.
///
/// E.g., each of `Clone`, `Copy` in `#[derive(Clone, Copy)]`.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum MetaItemInner {
/// A full MetaItem, for recursive meta items.
MetaItem(MetaItem),
/// A literal.
///
/// E.g., `"foo"`, `64`, `true`.
Lit(MetaItemLit),
}
/// A block (`{ .. }`).
///
/// E.g., `{ .. }` as in `fn foo() { .. }`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Block {
/// The statements in the block.
pub stmts: ThinVec<Stmt>,
pub id: NodeId,
/// Distinguishes between `unsafe { ... }` and `{ ... }`.
pub rules: BlockCheckMode,
pub span: Span,
pub tokens: Option<LazyAttrTokenStream>,
}
/// A match pattern.
///
/// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Pat {
pub id: NodeId,
pub kind: PatKind,
pub span: Span,
pub tokens: Option<LazyAttrTokenStream>,
}
impl Pat {
/// Attempt reparsing the pattern as a type.
/// This is intended for use by diagnostics.
pub fn to_ty(&self) -> Option<Box<Ty>> {
let kind = match &self.kind {
PatKind::Missing => unreachable!(),
// 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::NONE, 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, pinned, mutbl) => pat.to_ty().map(|ty| match pinned {
Pinnedness::Not => TyKind::Ref(None, MutTy { ty, mutbl: *mutbl }),
Pinnedness::Pinned => TyKind::PinnedRef(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 let [pat] = pats.as_slice() => {
pat.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 tys = pats.iter().map(|pat| pat.to_ty()).collect::<Option<ThinVec<_>>>()?;
TyKind::Tup(tys)
}
_ => return None,
};
Some(Box::new(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<'ast>(&'ast self, it: &mut impl FnMut(&'ast 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::Deref(s)
| PatKind::Ref(s, _, _)
| PatKind::Paren(s)
| PatKind::Guard(s, _) => s.walk(it),
// These patterns do not contain subpatterns, skip.
PatKind::Missing
| PatKind::Wild
| PatKind::Rest
| PatKind::Never
| PatKind::Expr(_)
| PatKind::Range(..)
| PatKind::Ident(..)
| PatKind::Path(..)
| PatKind::MacCall(_)
| PatKind::Err(_) => {}
}
}
/// Strip off all reference patterns (`&`, `&mut`) and return the inner pattern.
pub fn peel_refs(&self) -> &Pat {
let mut current = self;
while let PatKind::Ref(inner, _, _) = &current.kind {
current = inner;
}
current
}
/// Is this a `..` pattern?
pub fn is_rest(&self) -> bool {
matches!(self.kind, PatKind::Rest)
}
/// Whether this could be a never pattern, taking into account that a macro invocation can
/// return a never pattern. Used to inform errors during parsing.
pub fn could_be_never_pattern(&self) -> bool {
let mut could_be_never_pattern = false;
self.walk(&mut |pat| match &pat.kind {
PatKind::Never | PatKind::MacCall(_) => {
could_be_never_pattern = true;
false
}
PatKind::Or(s) => {
could_be_never_pattern = s.iter().all(|p| p.could_be_never_pattern());
false
}
_ => true,
});
could_be_never_pattern
}
/// Whether this contains a `!` pattern. This in particular means that a feature gate error will
/// be raised if the feature is off. Used to avoid gating the feature twice.
pub fn contains_never_pattern(&self) -> bool {
let mut contains_never_pattern = false;
self.walk(&mut |pat| {
if matches!(pat.kind, PatKind::Never) {
contains_never_pattern = true;
}
true
});
contains_never_pattern
}
/// Return a name suitable for diagnostics.
pub fn descr(&self) -> Option<String> {
match &self.kind {
PatKind::Missing => unreachable!(),
PatKind::Wild => Some("_".to_string()),
PatKind::Ident(BindingMode::NONE, ident, None) => Some(format!("{ident}")),
PatKind::Ref(pat, pinned, mutbl) => {
pat.descr().map(|d| format!("&{}{d}", pinned.prefix_str(*mutbl)))
}
_ => None,
}
}
}
impl From<Box<Pat>> for Pat {
fn from(value: Box<Pat>) -> Self {
*value
}
}
/// 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, Walkable)]
pub struct PatField {
/// The identifier for the field.
pub ident: Ident,
/// The pattern the field is destructured to.
pub pat: Box<Pat>,
pub is_shorthand: bool,
pub attrs: AttrVec,
pub id: NodeId,
pub span: Span,
pub is_placeholder: bool,
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[derive(Encodable, Decodable, HashStable_Generic, Walkable)]
pub enum ByRef {
Yes(Pinnedness, Mutability),
No,
}
impl ByRef {
#[must_use]
pub fn cap_ref_mutability(mut self, mutbl: Mutability) -> Self {
if let ByRef::Yes(_, old_mutbl) = &mut self {
*old_mutbl = cmp::min(*old_mutbl, mutbl);
}
self
}
}
/// The mode of a binding (`mut`, `ref mut`, etc).
/// Used for both the explicit binding annotations given in the HIR for a binding
/// and the final binding mode that we infer after type inference/match ergonomics.
/// `.0` is the by-reference mode (`ref`, `ref mut`, or by value),
/// `.1` is the mutability of the binding.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[derive(Encodable, Decodable, HashStable_Generic, Walkable)]
pub struct BindingMode(pub ByRef, pub Mutability);
impl BindingMode {
pub const NONE: Self = Self(ByRef::No, Mutability::Not);
pub const REF: Self = Self(ByRef::Yes(Pinnedness::Not, Mutability::Not), Mutability::Not);
pub const REF_PIN: Self =
Self(ByRef::Yes(Pinnedness::Pinned, Mutability::Not), Mutability::Not);
pub const MUT: Self = Self(ByRef::No, Mutability::Mut);
pub const REF_MUT: Self = Self(ByRef::Yes(Pinnedness::Not, Mutability::Mut), Mutability::Not);
pub const REF_PIN_MUT: Self =
Self(ByRef::Yes(Pinnedness::Pinned, Mutability::Mut), Mutability::Not);
pub const MUT_REF: Self = Self(ByRef::Yes(Pinnedness::Not, Mutability::Not), Mutability::Mut);
pub const MUT_REF_PIN: Self =
Self(ByRef::Yes(Pinnedness::Pinned, Mutability::Not), Mutability::Mut);
pub const MUT_REF_MUT: Self =
Self(ByRef::Yes(Pinnedness::Not, Mutability::Mut), Mutability::Mut);
pub const MUT_REF_PIN_MUT: Self =
Self(ByRef::Yes(Pinnedness::Pinned, Mutability::Mut), Mutability::Mut);
pub fn prefix_str(self) -> &'static str {
match self {
Self::NONE => "",
Self::REF => "ref ",
Self::REF_PIN => "ref pin const ",
Self::MUT => "mut ",
Self::REF_MUT => "ref mut ",
Self::REF_PIN_MUT => "ref pin mut ",
Self::MUT_REF => "mut ref ",
Self::MUT_REF_PIN => "mut ref pin ",
Self::MUT_REF_MUT => "mut ref mut ",
Self::MUT_REF_PIN_MUT => "mut ref pin mut ",
}
}
}
#[derive(Clone, Copy, Encodable, Decodable, Debug, Walkable)]
pub enum RangeEnd {
/// `..=` or `...`
Included(RangeSyntax),
/// `..`
Excluded,
}
#[derive(Clone, Copy, Encodable, Decodable, Debug, Walkable)]
pub enum RangeSyntax {
/// `...`
DotDotDot,
/// `..=`
DotDotEq,
}
/// All the different flavors of pattern that Rust recognizes.
//
// Adding a new variant? Please update `test_pat` in `tests/ui/macros/stringify.rs`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum PatKind {
/// A missing pattern, e.g. for an anonymous param in a bare fn like `fn f(u32)`.
Missing,
/// 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<Box<Pat>>),
/// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
Struct(Option<Box<QSelf>>, Path, ThinVec<PatField>, PatFieldsRest),
/// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
TupleStruct(Option<Box<QSelf>>, Path, ThinVec<Pat>),
/// An or-pattern `A | B | C`.
/// Invariant: `pats.len() >= 2`.
Or(ThinVec<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<Box<QSelf>>, Path),
/// A tuple pattern (`(a, b)`).
Tuple(ThinVec<Pat>),
/// A `box` pattern.
Box(Box<Pat>),
/// A `deref` pattern (currently `deref!()` macro-based syntax).
Deref(Box<Pat>),
/// A reference pattern (e.g., `&mut (a, b)`).
Ref(Box<Pat>, Pinnedness, Mutability),
/// A literal, const block or path.
Expr(Box<Expr>),
/// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
Range(Option<Box<Expr>>, Option<Box<Expr>>, Spanned<RangeEnd>),
/// A slice pattern `[a, b, c]`.
Slice(ThinVec<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: `$path(a, .., b)`.
///
/// In all of these cases, an additional restriction applies,
/// only one rest pattern may occur in the pattern sequences.
Rest,
// A never pattern `!`.
Never,
/// A guard pattern (e.g., `x if guard(x)`).
Guard(Box<Pat>, Box<Guard>),
/// Parentheses in patterns used for grouping (i.e., `(PAT)`).
Paren(Box<Pat>),
/// A macro pattern; pre-expansion.
MacCall(Box<MacCall>),
/// Placeholder for a pattern that wasn't syntactically well formed in some way.
Err(ErrorGuaranteed),
}
/// Whether the `..` is present in a struct fields pattern.
#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Walkable)]
pub enum PatFieldsRest {
/// `module::StructName { field, ..}`
Rest(Span),
/// `module::StructName { field, syntax error }`
Recovered(ErrorGuaranteed),
/// `module::StructName { field }`
None,
}
/// The kind of borrow in an `AddrOf` expression,
/// e.g., `&place` or `&raw const place`.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
#[derive(Encodable, Decodable, HashStable_Generic, Walkable)]
pub enum BorrowKind {
/// A normal borrow, `&$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,
/// A pinned borrow, `&pin const $expr` or `&pin mut $expr`.
/// The resulting type is either `Pin<&'a T>` or `Pin<&'a mut T>`
/// where `T = typeof($expr)` and `'a` is some lifetime.
Pin,
}
#[derive(Clone, Copy, Debug, PartialEq, Encodable, Decodable, HashStable_Generic, Walkable)]
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 as_str(&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 is_lazy(&self) -> bool {
matches!(self, BinOpKind::And | BinOpKind::Or)
}
pub fn precedence(&self) -> ExprPrecedence {
use BinOpKind::*;
match *self {
Mul | Div | Rem => ExprPrecedence::Product,
Add | Sub => ExprPrecedence::Sum,
Shl | Shr => ExprPrecedence::Shift,
BitAnd => ExprPrecedence::BitAnd,
BitXor => ExprPrecedence::BitXor,
BitOr => ExprPrecedence::BitOr,
Lt | Gt | Le | Ge | Eq | Ne => ExprPrecedence::Compare,
And => ExprPrecedence::LAnd,
Or => ExprPrecedence::LOr,
}
}
pub fn fixity(&self) -> Fixity {
use BinOpKind::*;
match self {
Eq | Ne | Lt | Le | Gt | Ge => Fixity::None,
Add | Sub | Mul | Div | Rem | And | Or | BitXor | BitAnd | BitOr | Shl | Shr => {
Fixity::Left
}
}
}
pub fn is_comparison(self) -> bool {
use BinOpKind::*;
match self {
Eq | Ne | Lt | Le | Gt | Ge => true,
Add | Sub | Mul | Div | Rem | And | Or | BitXor | BitAnd | BitOr | Shl | Shr => false,
}
}
/// Returns `true` if the binary operator takes its arguments by value.
pub fn is_by_value(self) -> bool {
!self.is_comparison()
}
}
pub type BinOp = Spanned<BinOpKind>;
// Sometimes `BinOpKind` and `AssignOpKind` need the same treatment. The
// operations covered by `AssignOpKind` are a subset of those covered by
// `BinOpKind`, so it makes sense to convert `AssignOpKind` to `BinOpKind`.
impl From<AssignOpKind> for BinOpKind {
fn from(op: AssignOpKind) -> BinOpKind {
match op {
AssignOpKind::AddAssign => BinOpKind::Add,
AssignOpKind::SubAssign => BinOpKind::Sub,
AssignOpKind::MulAssign => BinOpKind::Mul,
AssignOpKind::DivAssign => BinOpKind::Div,
AssignOpKind::RemAssign => BinOpKind::Rem,
AssignOpKind::BitXorAssign => BinOpKind::BitXor,
AssignOpKind::BitAndAssign => BinOpKind::BitAnd,
AssignOpKind::BitOrAssign => BinOpKind::BitOr,
AssignOpKind::ShlAssign => BinOpKind::Shl,
AssignOpKind::ShrAssign => BinOpKind::Shr,
}
}
}
#[derive(Clone, Copy, Debug, PartialEq, Encodable, Decodable, HashStable_Generic, Walkable)]
pub enum AssignOpKind {
/// The `+=` operator (addition)
AddAssign,
/// The `-=` operator (subtraction)
SubAssign,
/// The `*=` operator (multiplication)
MulAssign,
/// The `/=` operator (division)
DivAssign,
/// The `%=` operator (modulus)
RemAssign,
/// The `^=` operator (bitwise xor)
BitXorAssign,
/// The `&=` operator (bitwise and)
BitAndAssign,
/// The `|=` operator (bitwise or)
BitOrAssign,
/// The `<<=` operator (shift left)
ShlAssign,
/// The `>>=` operator (shift right)
ShrAssign,
}
impl AssignOpKind {
pub fn as_str(&self) -> &'static str {
use AssignOpKind::*;
match self {
AddAssign => "+=",
SubAssign => "-=",
MulAssign => "*=",
DivAssign => "/=",
RemAssign => "%=",
BitXorAssign => "^=",
BitAndAssign => "&=",
BitOrAssign => "|=",
ShlAssign => "<<=",
ShrAssign => ">>=",
}
}
/// AssignOps are always by value.
pub fn is_by_value(self) -> bool {
true
}
}
pub type AssignOp = Spanned<AssignOpKind>;
/// Unary operator.
///
/// Note that `&data` is not an operator, it's an `AddrOf` expression.
#[derive(Clone, Copy, Debug, PartialEq, Encodable, Decodable, HashStable_Generic, Walkable)]
pub enum UnOp {
/// The `*` operator for dereferencing
Deref,
/// The `!` operator for logical inversion
Not,
/// The `-` operator for negation
Neg,
}
impl UnOp {
pub fn as_str(&self) -> &'static str {
match self {
UnOp::Deref => "*",
UnOp::Not => "!",
UnOp::Neg => "-",
}
}
/// Returns `true` if the unary operator takes its argument by value.
pub fn is_by_value(self) -> bool {
matches!(self, Self::Neg | Self::Not)
}
}
/// A statement. No `attrs` or `tokens` fields because each `StmtKind` variant
/// contains an AST node with those fields. (Except for `StmtKind::Empty`,
/// which never has attrs or tokens)
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Stmt {
pub id: NodeId,
pub kind: StmtKind,
pub span: Span,
}
impl Stmt {
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
/// `LazyAttrTokenStream`. The parser is responsible for calling
/// `ToAttrTokenStream::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(mut mac) => {
mac.style = MacStmtStyle::Semicolon;
StmtKind::MacCall(mac)
}
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(_))
}
}
// Adding a new variant? Please update `test_stmt` in `tests/ui/macros/stringify.rs`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum StmtKind {
/// A local (let) binding.
Let(Box<Local>),
/// An item definition.
Item(Box<Item>),
/// Expr without trailing semi-colon.
Expr(Box<Expr>),
/// Expr with a trailing semi-colon.
Semi(Box<Expr>),
/// Just a trailing semi-colon.
Empty,
/// Macro.
MacCall(Box<MacCallStmt>),
}
impl StmtKind {
pub fn descr(&self) -> &'static str {
match self {
StmtKind::Let(_) => "local",
StmtKind::Item(_) => "item",
StmtKind::Expr(_) => "expression",
StmtKind::Semi(_) => "statement",
StmtKind::Empty => "semicolon",
StmtKind::MacCall(_) => "macro call",
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct MacCallStmt {
pub mac: Box<MacCall>,
pub style: MacStmtStyle,
pub attrs: AttrVec,
pub tokens: Option<LazyAttrTokenStream>,
}
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, Walkable)]
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, Walkable)]
pub struct Local {
pub id: NodeId,
pub super_: Option<Span>,
pub pat: Box<Pat>,
pub ty: Option<Box<Ty>>,
pub kind: LocalKind,
pub span: Span,
pub colon_sp: Option<Span>,
pub attrs: AttrVec,
pub tokens: Option<LazyAttrTokenStream>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum LocalKind {
/// Local declaration.
/// Example: `let x;`
Decl,
/// Local declaration with an initializer.
/// Example: `let x = y;`
Init(Box<Expr>),
/// Local declaration with an initializer and an `else` clause.
/// Example: `let Some(x) = y else { return };`
InitElse(Box<Expr>, Box<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, Walkable)]
pub struct Arm {
pub attrs: AttrVec,
/// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`.
pub pat: Box<Pat>,
/// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`.
pub guard: Option<Box<Guard>>,
/// Match arm body. Omitted if the pattern is a never pattern.
pub body: Option<Box<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, Walkable)]
pub struct ExprField {
pub attrs: AttrVec,
pub id: NodeId,
pub span: Span,
pub ident: Ident,
pub expr: Box<Expr>,
pub is_shorthand: bool,
pub is_placeholder: bool,
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, Walkable)]
pub enum BlockCheckMode {
Default,
Unsafe(UnsafeSource),
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, Walkable)]
pub enum UnsafeSource {
CompilerGenerated,
UserProvided,
}
/// Track whether under `feature(min_generic_const_args)` this anon const
/// was explicitly disambiguated as an anon const or not through the use of
/// `const { ... }` syntax.
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, Walkable)]
pub enum MgcaDisambiguation {
AnonConst,
Direct,
}
/// 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, Walkable)]
pub struct AnonConst {
pub id: NodeId,
pub value: Box<Expr>,
pub mgca_disambiguation: MgcaDisambiguation,
}
/// 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<LazyAttrTokenStream>,
}
impl Expr {
/// Check if this expression is potentially a trivial const arg, i.e., one that can _potentially_
/// be represented without an anon const in the HIR.
///
/// This will unwrap at most one block level (curly braces). After that, if the expression
/// is a path, it mostly dispatches to [`Path::is_potential_trivial_const_arg`].
///
/// This function will only allow paths with no qself, before dispatching to the `Path`
/// function of the same name.
///
/// Does not ensure that the path resolves to a const param/item, the caller should check this.
/// This also does not consider macros, so it's only correct after macro-expansion.
pub fn is_potential_trivial_const_arg(&self) -> bool {
let this = self.maybe_unwrap_block();
if let ExprKind::Path(None, path) = &this.kind
&& path.is_potential_trivial_const_arg()
{
true
} else {
false
}
}
/// Returns an expression with (when possible) *one* outer brace removed
pub fn maybe_unwrap_block(&self) -> &Expr {
if let ExprKind::Block(block, None) = &self.kind
&& let [stmt] = block.stmts.as_slice()
&& let StmtKind::Expr(expr) = &stmt.kind
{
expr
} else {
self
}
}
/// Determines whether this expression is a macro call optionally wrapped in braces . If
/// `already_stripped_block` is set then we do not attempt to peel off a layer of braces.
///
/// Returns the [`NodeId`] of the macro call and whether a layer of braces has been peeled
/// either before, or part of, this function.
pub fn optionally_braced_mac_call(
&self,
already_stripped_block: bool,
) -> Option<(bool, NodeId)> {
match &self.kind {
ExprKind::Block(block, None)
if let [stmt] = &*block.stmts
&& !already_stripped_block =>
{
match &stmt.kind {
StmtKind::MacCall(_) => Some((true, stmt.id)),
StmtKind::Expr(expr) if let ExprKind::MacCall(_) = &expr.kind => {
Some((true, expr.id))
}
_ => None,
}
}
ExprKind::MacCall(_) => Some((already_stripped_block, self.id)),
_ => None,
}
}
pub fn to_bound(&self) -> Option<GenericBound> {
match &self.kind {
ExprKind::Path(None, path) => Some(GenericBound::Trait(PolyTraitRef::new(
ThinVec::new(),
path.clone(),
TraitBoundModifiers::NONE,
self.span,
Parens::No,
))),
_ => None,
}
}
pub fn peel_parens(&self) -> &Expr {
let mut expr = self;
while let ExprKind::Paren(inner) = &expr.kind {
expr = inner;
}
expr
}
pub fn peel_parens_and_refs(&self) -> &Expr {
let mut expr = self;
while let ExprKind::Paren(inner) | ExprKind::AddrOf(BorrowKind::Ref, _, inner) = &expr.kind
{
expr = inner;
}
expr
}
/// Attempts to reparse as `Ty` (for diagnostic purposes).
pub fn to_ty(&self) -> Option<Box<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::Ref(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 let [expr] = exprs.as_slice() => {
expr.to_ty().map(TyKind::Slice)?
}
ExprKind::Tup(exprs) => {
let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<ThinVec<_>>>()?;
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 => {
let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) else {
return None;
};
TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
}
ExprKind::Underscore => TyKind::Infer,
// This expression doesn't look like a type syntactically.
_ => return None,
};
Some(Box::new(Ty { kind, id: self.id, span: self.span, tokens: None }))
}
pub fn precedence(&self) -> ExprPrecedence {
fn prefix_attrs_precedence(attrs: &AttrVec) -> ExprPrecedence {
for attr in attrs {
if let AttrStyle::Outer = attr.style {
return ExprPrecedence::Prefix;
}
}
ExprPrecedence::Unambiguous
}
match &self.kind {
ExprKind::Closure(closure) => {
match closure.fn_decl.output {
FnRetTy::Default(_) => ExprPrecedence::Jump,
FnRetTy::Ty(_) => prefix_attrs_precedence(&self.attrs),
}
}
ExprKind::Break(_ /*label*/, value)
| ExprKind::Ret(value)
| ExprKind::Yield(YieldKind::Prefix(value))
| ExprKind::Yeet(value) => match value {
Some(_) => ExprPrecedence::Jump,
None => prefix_attrs_precedence(&self.attrs),
},
ExprKind::Become(_) => ExprPrecedence::Jump,
// `Range` claims to have higher precedence than `Assign`, but `x .. x = x` fails to
// parse, instead of parsing as `(x .. x) = x`. Giving `Range` a lower precedence
// ensures that `pprust` will add parentheses in the right places to get the desired
// parse.
ExprKind::Range(..) => ExprPrecedence::Range,
// Binop-like expr kinds, handled by `AssocOp`.
ExprKind::Binary(op, ..) => op.node.precedence(),
ExprKind::Cast(..) => ExprPrecedence::Cast,
ExprKind::Assign(..) |
ExprKind::AssignOp(..) => ExprPrecedence::Assign,
// Unary, prefix
ExprKind::AddrOf(..)
// Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
// However, this is not exactly right. When `let _ = a` is the LHS of a binop we
// need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
// but we need to print `(let _ = a) < b` as-is with parens.
| ExprKind::Let(..)
| ExprKind::Unary(..) => ExprPrecedence::Prefix,
// Need parens if and only if there are prefix attributes.
ExprKind::Array(_)
| ExprKind::Await(..)
| ExprKind::Use(..)
| ExprKind::Block(..)
| ExprKind::Call(..)
| ExprKind::ConstBlock(_)
| ExprKind::Continue(..)
| ExprKind::Field(..)
| ExprKind::ForLoop { .. }
| ExprKind::FormatArgs(..)
| ExprKind::Gen(..)
| ExprKind::If(..)
| ExprKind::IncludedBytes(..)
| ExprKind::Index(..)
| ExprKind::InlineAsm(..)
| ExprKind::Lit(_)
| ExprKind::Loop(..)
| ExprKind::MacCall(..)
| ExprKind::Match(..)
| ExprKind::MethodCall(..)
| ExprKind::OffsetOf(..)
| ExprKind::Paren(..)
| ExprKind::Path(..)
| ExprKind::Repeat(..)
| ExprKind::Struct(..)
| ExprKind::Try(..)
| ExprKind::TryBlock(..)
| ExprKind::Tup(_)
| ExprKind::Type(..)
| ExprKind::Underscore
| ExprKind::UnsafeBinderCast(..)
| ExprKind::While(..)
| ExprKind::Yield(YieldKind::Postfix(..))
| ExprKind::Err(_)
| ExprKind::Dummy => prefix_attrs_precedence(&self.attrs),
}
}
/// To a first-order approximation, is this a pattern?
pub fn is_approximately_pattern(&self) -> bool {
matches!(
&self.peel_parens().kind,
ExprKind::Array(_)
| ExprKind::Call(_, _)
| ExprKind::Tup(_)
| ExprKind::Lit(_)
| ExprKind::Range(_, _, _)
| ExprKind::Underscore
| ExprKind::Path(_, _)
| ExprKind::Struct(_)
)
}
/// Creates a dummy `Expr`.
///
/// Should only be used when it will be replaced afterwards or as a return value when an error was encountered.
pub fn dummy() -> Expr {
Expr {
id: DUMMY_NODE_ID,
kind: ExprKind::Dummy,
span: DUMMY_SP,
attrs: ThinVec::new(),
tokens: None,
}
}
}
impl From<Box<Expr>> for Expr {
fn from(value: Box<Expr>) -> Self {
*value
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Closure {
pub binder: ClosureBinder,
pub capture_clause: CaptureBy,
pub constness: Const,
pub coroutine_kind: Option<CoroutineKind>,
pub movability: Movability,
pub fn_decl: Box<FnDecl>,
pub body: Box<Expr>,
/// The span of the declaration block: 'move |...| -> ...'
pub fn_decl_span: Span,
/// The span of the argument block `|...|`
pub fn_arg_span: Span,
}
/// Limit types of a range (inclusive or exclusive).
#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, Walkable)]
pub enum RangeLimits {
/// Inclusive at the beginning, exclusive at the end.
HalfOpen,
/// Inclusive at the beginning and end.
Closed,
}
impl RangeLimits {
pub fn as_str(&self) -> &'static str {
match self {
RangeLimits::HalfOpen => "..",
RangeLimits::Closed => "..=",
}
}
}
/// A method call (e.g. `x.foo::<Bar, Baz>(a, b, c)`).
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct MethodCall {
/// The method name and its generic arguments, e.g. `foo::<Bar, Baz>`.
pub seg: PathSegment,
/// The receiver, e.g. `x`.
pub receiver: Box<Expr>,
/// The arguments, e.g. `a, b, c`.
pub args: ThinVec<Box<Expr>>,
/// The span of the function, without the dot and receiver e.g. `foo::<Bar,
/// Baz>(a, b, c)`.
pub span: Span,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum StructRest {
/// `..x`.
Base(Box<Expr>),
/// `..`.
Rest(Span),
/// No trailing `..` or expression.
None,
/// No trailing `..` or expression, and also, a parse error occurred inside the struct braces.
///
/// This struct should be treated similarly to as if it had an `..` in it,
/// in particular rather than reporting missing fields, because the parse error
/// makes which fields the struct was intended to have not fully known.
NoneWithError(ErrorGuaranteed),
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct StructExpr {
pub qself: Option<Box<QSelf>>,
pub path: Path,
pub fields: ThinVec<ExprField>,
pub rest: StructRest,
}
// Adding a new variant? Please update `test_expr` in `tests/ui/macros/stringify.rs`.
#[derive(Clone, Encodable, Decodable, Debug)]
pub enum ExprKind {
/// An array (e.g, `[a, b, c, d]`).
Array(ThinVec<Box<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(Box<Expr>, ThinVec<Box<Expr>>),
/// A method call (e.g., `x.foo::<Bar, Baz>(a, b, c)`).
MethodCall(Box<MethodCall>),
/// A tuple (e.g., `(a, b, c, d)`).
Tup(ThinVec<Box<Expr>>),
/// A binary operation (e.g., `a + b`, `a * b`).
Binary(BinOp, Box<Expr>, Box<Expr>),
/// A unary operation (e.g., `!x`, `*x`).
Unary(UnOp, Box<Expr>),
/// A literal (e.g., `1`, `"foo"`).
Lit(token::Lit),
/// A cast (e.g., `foo as f64`).
Cast(Box<Expr>, Box<Ty>),
/// A type ascription (e.g., `builtin # type_ascribe(42, usize)`).
///
/// Usually not written directly in user code but
/// indirectly via the macro `type_ascribe!(...)`.
Type(Box<Expr>, Box<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(Box<Pat>, Box<Expr>, Span, Recovered),
/// An `if` block, with an optional `else` block.
///
/// `if expr { block } else { expr }`
///
/// If present, the "else" expr is always `ExprKind::Block` (for `else`) or
/// `ExprKind::If` (for `else if`).
If(Box<Expr>, Box<Block>, Option<Box<Expr>>),
/// A while loop, with an optional label.
///
/// `'label: while expr { block }`
While(Box<Expr>, Box<Block>, Option<Label>),
/// A `for` loop, with an optional label.
///
/// `'label: for await? pat in iter { block }`
///
/// This is desugared to a combination of `loop` and `match` expressions.
ForLoop {
pat: Box<Pat>,
iter: Box<Expr>,
body: Box<Block>,
label: Option<Label>,
kind: ForLoopKind,
},
/// Conditionless loop (can be exited with `break`, `continue`, or `return`).
///
/// `'label: loop { block }`
Loop(Box<Block>, Option<Label>, Span),
/// A `match` block.
Match(Box<Expr>, ThinVec<Arm>, MatchKind),
/// A closure (e.g., `move |a, b, c| a + b + c`).
Closure(Box<Closure>),
/// A block (`'label: { ... }`).
Block(Box<Block>, Option<Label>),
/// An `async` block (`async move { ... }`),
/// or a `gen` block (`gen move { ... }`).
///
/// The span is the "decl", which is the header before the body `{ }`
/// including the `async`/`gen` keywords and possibly `move`.
Gen(CaptureBy, Box<Block>, GenBlockKind, Span),
/// An await expression (`my_future.await`). Span is of await keyword.
Await(Box<Expr>, Span),
/// A use expression (`x.use`). Span is of use keyword.
Use(Box<Expr>, Span),
/// A try block (`try { ... }`), if the type is `None`, or
/// A try block (`try bikeshed Ty { ... }`) if the type is `Some`.
///
/// Note that `try bikeshed` is a *deliberately ridiculous* placeholder
/// syntax to avoid deciding what keyword or symbol should go there.
/// It's that way for experimentation only; an RFC to decide the final
/// semantics and syntax would be needed to put it on stabilization-track.
TryBlock(Box<Block>, Option<Box<Ty>>),
/// An assignment (`a = foo()`).
/// The `Span` argument is the span of the `=` token.
Assign(Box<Expr>, Box<Expr>, Span),
/// An assignment with an operator.
///
/// E.g., `a += 1`.
AssignOp(AssignOp, Box<Expr>, Box<Expr>),
/// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
Field(Box<Expr>, Ident),
/// An indexing operation (e.g., `foo[2]`).
/// The span represents the span of the `[2]`, including brackets.
Index(Box<Expr>, Box<Expr>, Span),
/// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assignment).
Range(Option<Box<Expr>>, Option<Box<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<Box<QSelf>>, Path),
/// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
AddrOf(BorrowKind, Mutability, Box<Expr>),
/// A `break`, with an optional label to break, and an optional expression.
Break(Option<Label>, Option<Box<Expr>>),
/// A `continue`, with an optional label.
Continue(Option<Label>),
/// A `return`, with an optional value to be returned.
Ret(Option<Box<Expr>>),
/// Output of the `asm!()` macro.
InlineAsm(Box<InlineAsm>),
/// An `offset_of` expression (e.g., `builtin # offset_of(Struct, field)`).
///
/// Usually not written directly in user code but
/// indirectly via the macro `core::mem::offset_of!(...)`.
OffsetOf(Box<Ty>, Vec<Ident>),
/// A macro invocation; pre-expansion.
MacCall(Box<MacCall>),
/// A struct literal expression.
///
/// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
Struct(Box<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(Box<Expr>, AnonConst),
/// No-op: used solely so we can pretty-print faithfully.
Paren(Box<Expr>),
/// A try expression (`expr?`).
Try(Box<Expr>),
/// A `yield`, with an optional value to be yielded.
Yield(YieldKind),
/// A `do yeet` (aka `throw`/`fail`/`bail`/`raise`/whatever),
/// with an optional value to be returned.
Yeet(Option<Box<Expr>>),
/// A tail call return, with the value to be returned.
///
/// While `.0` must be a function call, we check this later, after parsing.
Become(Box<Expr>),
/// Bytes included via `include_bytes!`
///
/// Added for optimization purposes to avoid the need to escape
/// large binary blobs - should always behave like [`ExprKind::Lit`]
/// with a `ByteStr` literal.
///
/// The value is stored as a `ByteSymbol`. It's unfortunate that we need to
/// intern (hash) the bytes because they're likely to be large and unique.
/// But it's necessary because this will eventually be lowered to
/// `LitKind::ByteStr`, which needs a `ByteSymbol` to impl `Copy` and avoid
/// arena allocation.
IncludedBytes(ByteSymbol),
/// A `format_args!()` expression.
FormatArgs(Box<FormatArgs>),
UnsafeBinderCast(UnsafeBinderCastKind, Box<Expr>, Option<Box<Ty>>),
/// Placeholder for an expression that wasn't syntactically well formed in some way.
Err(ErrorGuaranteed),
/// Acts as a null expression. Lowering it will always emit a bug.
Dummy,
}
/// Used to differentiate between `for` loops and `for await` loops.
#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Eq, Walkable)]
pub enum ForLoopKind {
For,
ForAwait,
}
/// Used to differentiate between `async {}` blocks and `gen {}` blocks.
#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Eq, Walkable)]
pub enum GenBlockKind {
Async,
Gen,
AsyncGen,
}
impl fmt::Display for GenBlockKind {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.modifier().fmt(f)
}
}
impl GenBlockKind {
pub fn modifier(&self) -> &'static str {
match self {
GenBlockKind::Async => "async",
GenBlockKind::Gen => "gen",
GenBlockKind::AsyncGen => "async gen",
}
}
}
/// Whether we're unwrapping or wrapping an unsafe binder
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
#[derive(Encodable, Decodable, HashStable_Generic, Walkable)]
pub enum UnsafeBinderCastKind {
// e.g. `&i32` -> `unsafe<'a> &'a i32`
Wrap,
// e.g. `unsafe<'a> &'a i32` -> `&i32`
Unwrap,
}
/// 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, Walkable)]
pub struct QSelf {
pub ty: Box<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, Walkable)]
pub enum CaptureBy {
/// `move |x| y + x`.
Value {
/// The span of the `move` keyword.
move_kw: Span,
},
/// `move` or `use` keywords were not specified.
Ref,
/// `use |x| y + x`.
///
/// Note that if you have a regular closure like `|| x.use`, this will *not* result
/// in a `Use` capture. Instead, the `ExprUseVisitor` will look at the type
/// of `x` and treat `x.use` as either a copy/clone/move as appropriate.
Use {
/// The span of the `use` keyword.
use_kw: Span,
},
}
/// Closure lifetime binder, `for<'a, 'b>` in `for<'a, 'b> |_: &'a (), _: &'b ()|`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum ClosureBinder {
/// The binder is not present, all closure lifetimes are inferred.
NotPresent,
/// The binder is present.
For {
/// Span of the whole `for<>` clause
///
/// ```text
/// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
/// ^^^^^^^^^^^ -- this
/// ```
span: Span,
/// Lifetimes in the `for<>` closure
///
/// ```text
/// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
/// ^^^^^^ -- this
/// ```
generic_params: ThinVec<GenericParam>,
},
}
/// 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, Walkable)]
pub struct MacCall {
pub path: Path,
pub args: Box<DelimArgs>,
}
impl MacCall {
pub fn span(&self) -> Span {
self.path.span.to(self.args.dspan.entire())
}
}
/// Arguments passed to an attribute macro.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum AttrArgs {
/// No arguments: `#[attr]`.
Empty,
/// Delimited arguments: `#[attr()/[]/{}]`.
Delimited(DelimArgs),
/// Arguments of a key-value attribute: `#[attr = "value"]`.
Eq {
/// Span of the `=` token.
eq_span: Span,
expr: Box<Expr>,
},
}
impl AttrArgs {
pub fn span(&self) -> Option<Span> {
match self {
AttrArgs::Empty => None,
AttrArgs::Delimited(args) => Some(args.dspan.entire()),
AttrArgs::Eq { eq_span, expr } => Some(eq_span.to(expr.span)),
}
}
/// Tokens inside the delimiters or after `=`.
/// Proc macros see these tokens, for example.
pub fn inner_tokens(&self) -> TokenStream {
match self {
AttrArgs::Empty => TokenStream::default(),
AttrArgs::Delimited(args) => args.tokens.clone(),
AttrArgs::Eq { expr, .. } => TokenStream::from_ast(expr),
}
}
}
/// Delimited arguments, as used in `#[attr()/[]/{}]` or `mac!()/[]/{}`.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic, Walkable)]
pub struct DelimArgs {
pub dspan: DelimSpan,
pub delim: Delimiter, // Note: `Delimiter::Invisible` never occurs
pub tokens: TokenStream,
}
impl DelimArgs {
/// 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, DelimArgs { delim: Delimiter::Brace, .. })
}
}
/// Represents a macro definition.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic, Walkable)]
pub struct MacroDef {
pub body: Box<DelimArgs>,
/// `true` if macro was defined with `macro_rules`.
pub macro_rules: bool,
/// Corresponds to `#[eii_declaration(...)]`.
/// `#[eii_declaration(...)]` is a built-in attribute macro, not a built-in attribute,
/// because we require some name resolution to occur in the parameters of this attribute.
/// Name resolution isn't possible in attributes otherwise, so we encode it in the AST.
/// During ast lowering, we turn it back into an attribute again
pub eii_declaration: Option<EiiDecl>,
}
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic, Walkable)]
pub struct EiiDecl {
/// path to the extern item we're targeting
pub foreign_item: Path,
pub impl_unsafe: bool,
}
#[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
#[derive(HashStable_Generic, Walkable)]
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),
}
/// The kind of match expression
#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Walkable)]
pub enum MatchKind {
/// match expr { ... }
Prefix,
/// expr.match { ... }
Postfix,
}
/// The kind of yield expression
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum YieldKind {
/// yield expr { ... }
Prefix(Option<Box<Expr>>),
/// expr.yield { ... }
Postfix(Box<Expr>),
}
impl YieldKind {
/// Returns the expression inside the yield expression, if any.
///
/// For postfix yields, this is guaranteed to be `Some`.
pub const fn expr(&self) -> Option<&Box<Expr>> {
match self {
YieldKind::Prefix(expr) => expr.as_ref(),
YieldKind::Postfix(expr) => Some(expr),
}
}
/// Returns a mutable reference to the expression being yielded, if any.
pub const fn expr_mut(&mut self) -> Option<&mut Box<Expr>> {
match self {
YieldKind::Prefix(expr) => expr.as_mut(),
YieldKind::Postfix(expr) => Some(expr),
}
}
/// Returns true if both yields are prefix or both are postfix.
pub const fn same_kind(&self, other: &Self) -> bool {
match (self, other) {
(YieldKind::Prefix(_), YieldKind::Prefix(_)) => true,
(YieldKind::Postfix(_), YieldKind::Postfix(_)) => true,
_ => false,
}
}
}
/// A literal in a meta item.
#[derive(Clone, Copy, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct MetaItemLit {
/// The original literal as written in the source code.
pub symbol: Symbol,
/// The original suffix as written in the source code.
pub suffix: Option<Symbol>,
/// The "semantic" representation of the literal lowered from the original tokens.
/// Strings are unescaped, hexadecimal forms are eliminated, etc.
pub kind: LitKind,
pub span: Span,
}
/// Similar to `MetaItemLit`, but restricted to string literals.
#[derive(Clone, Copy, Encodable, Decodable, Debug, Walkable)]
pub struct StrLit {
/// The original literal as written in source code.
pub symbol: Symbol,
/// The original suffix as written in source code.
pub suffix: Option<Symbol>,
/// The semantic (unescaped) representation of the literal.
pub symbol_unescaped: Symbol,
pub style: StrStyle,
pub span: Span,
}
impl StrLit {
pub fn as_token_lit(&self) -> token::Lit {
let token_kind = match self.style {
StrStyle::Cooked => token::Str,
StrStyle::Raw(n) => token::StrRaw(n),
};
token::Lit::new(token_kind, self.symbol, self.suffix)
}
}
/// 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,
}
/// This type is used within both `ast::MetaItemLit` and `hir::Lit`.
///
/// Note that the entire literal (including the suffix) is considered when
/// deciding the `LitKind`. This means that float literals like `1f32` are
/// classified by this type as `Float`. This is different to `token::LitKind`
/// which does *not* consider the suffix.
#[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
pub enum LitKind {
/// A string literal (`"foo"`). The symbol is unescaped, and so may differ
/// from the original token's symbol.
Str(Symbol, StrStyle),
/// A byte string (`b"foo"`). The symbol is unescaped, and so may differ
/// from the original token's symbol.
ByteStr(ByteSymbol, StrStyle),
/// A C String (`c"foo"`). Guaranteed to only have `\0` at the end. The
/// symbol is unescaped, and so may differ from the original token's
/// symbol.
CStr(ByteSymbol, StrStyle),
/// A byte char (`b'f'`).
Byte(u8),
/// A character literal (`'a'`).
Char(char),
/// An integer literal (`1`).
Int(Pu128, LitIntType),
/// A float literal (`1.0`, `1f64` or `1E10f64`). The pre-suffix part is
/// stored as a symbol rather than `f64` so that `LitKind` can impl `Eq`
/// and `Hash`.
Float(Symbol, LitFloatType),
/// A boolean literal (`true`, `false`).
Bool(bool),
/// Placeholder for a literal that wasn't well-formed in some way.
Err(ErrorGuaranteed),
}
impl LitKind {
pub fn str(&self) -> Option<Symbol> {
match *self {
LitKind::Str(s, _) => Some(s),
_ => None,
}
}
/// 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::CStr(..)
| 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, Walkable)]
pub struct MutTy {
pub ty: Box<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: Box<FnDecl>,
pub span: Span,
}
impl FnSig {
/// Return a span encompassing the header, or where to insert it if empty.
pub fn header_span(&self) -> Span {
match self.header.ext {
Extern::Implicit(span) | Extern::Explicit(_, span) => {
return self.span.with_hi(span.hi());
}
Extern::None => {}
}
match self.header.safety {
Safety::Unsafe(span) | Safety::Safe(span) => return self.span.with_hi(span.hi()),
Safety::Default => {}
};
if let Some(coroutine_kind) = self.header.coroutine_kind {
return self.span.with_hi(coroutine_kind.span().hi());
}
if let Const::Yes(span) = self.header.constness {
return self.span.with_hi(span.hi());
}
self.span.shrink_to_lo()
}
/// The span of the header's safety, or where to insert it if empty.
pub fn safety_span(&self) -> Span {
match self.header.safety {
Safety::Unsafe(span) | Safety::Safe(span) => span,
Safety::Default => {
// Insert after the `coroutine_kind` if available.
if let Some(extern_span) = self.header.ext.span() {
return extern_span.shrink_to_lo();
}
// Insert right at the front of the signature.
self.header_span().shrink_to_hi()
}
}
}
/// The span of the header's extern, or where to insert it if empty.
pub fn extern_span(&self) -> Span {
self.header.ext.span().unwrap_or(self.safety_span().shrink_to_hi())
}
}
/// A constraint on an associated item.
///
/// ### Examples
///
/// * the `A = Ty` and `B = Ty` in `Trait<A = Ty, B = Ty>`
/// * the `G<Ty> = Ty` in `Trait<G<Ty> = Ty>`
/// * the `A: Bound` in `Trait<A: Bound>`
/// * the `RetTy` in `Trait(ArgTy, ArgTy) -> RetTy`
/// * the `C = { Ct }` in `Trait<C = { Ct }>` (feature `min_generic_const_args`)
/// * the `f(..): Bound` in `Trait<f(..): Bound>` (feature `return_type_notation`)
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct AssocItemConstraint {
pub id: NodeId,
pub ident: Ident,
pub gen_args: Option<GenericArgs>,
pub kind: AssocItemConstraintKind,
pub span: Span,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum Term {
Ty(Box<Ty>),
Const(AnonConst),
}
impl From<Box<Ty>> for Term {
fn from(v: Box<Ty>) -> Self {
Term::Ty(v)
}
}
impl From<AnonConst> for Term {
fn from(v: AnonConst) -> Self {
Term::Const(v)
}
}
/// The kind of [associated item constraint][AssocItemConstraint].
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum AssocItemConstraintKind {
/// An equality constraint for an associated item (e.g., `AssocTy = Ty` in `Trait<AssocTy = Ty>`).
///
/// Also known as an *associated item binding* (we *bind* an associated item to a term).
///
/// Furthermore, associated type equality constraints can also be referred to as *associated type
/// bindings*. Similarly with associated const equality constraints and *associated const bindings*.
Equality { term: Term },
/// A bound on an associated type (e.g., `AssocTy: Bound` in `Trait<AssocTy: Bound>`).
Bound {
#[visitable(extra = BoundKind::Bound)]
bounds: GenericBounds,
},
}
#[derive(Encodable, Decodable, Debug, Walkable)]
pub struct Ty {
pub id: NodeId,
pub kind: TyKind,
pub span: Span,
pub tokens: Option<LazyAttrTokenStream>,
}
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 From<Box<Ty>> for Ty {
fn from(value: Box<Ty>) -> Self {
*value
}
}
impl Ty {
pub fn peel_refs(&self) -> &Self {
let mut final_ty = self;
while let TyKind::Ref(_, MutTy { ty, .. }) | TyKind::Ptr(MutTy { ty, .. }) = &final_ty.kind
{
final_ty = ty;
}
final_ty
}
pub fn is_maybe_parenthesised_infer(&self) -> bool {
match &self.kind {
TyKind::Infer => true,
TyKind::Paren(inner) => inner.is_maybe_parenthesised_infer(),
_ => false,
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct FnPtrTy {
pub safety: Safety,
pub ext: Extern,
pub generic_params: ThinVec<GenericParam>,
pub decl: Box<FnDecl>,
/// Span of the `[unsafe] [extern] fn(...) -> ...` part, i.e. everything
/// after the generic params (if there are any, e.g. `for<'a>`).
pub decl_span: Span,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct UnsafeBinderTy {
pub generic_params: ThinVec<GenericParam>,
pub inner_ty: Box<Ty>,
}
/// The various kinds of type recognized by the compiler.
//
// Adding a new variant? Please update `test_ty` in `tests/ui/macros/stringify.rs`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum TyKind {
/// A variable-length slice (`[T]`).
Slice(Box<Ty>),
/// A fixed length array (`[T; n]`).
Array(Box<Ty>, AnonConst),
/// A raw pointer (`*const T` or `*mut T`).
Ptr(MutTy),
/// A reference (`&'a T` or `&'a mut T`).
Ref(#[visitable(extra = LifetimeCtxt::Ref)] Option<Lifetime>, MutTy),
/// A pinned reference (`&'a pin const T` or `&'a pin mut T`).
///
/// Desugars into `Pin<&'a T>` or `Pin<&'a mut T>`.
PinnedRef(#[visitable(extra = LifetimeCtxt::Ref)] Option<Lifetime>, MutTy),
/// A function pointer type (e.g., `fn(usize) -> bool`).
FnPtr(Box<FnPtrTy>),
/// An unsafe existential lifetime binder (e.g., `unsafe<'a> &'a ()`).
UnsafeBinder(Box<UnsafeBinderTy>),
/// The never type (`!`).
Never,
/// A tuple (`(A, B, C, D,...)`).
Tup(ThinVec<Box<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<Box<QSelf>>, Path),
/// A trait object type `Bound1 + Bound2 + Bound3`
/// where `Bound` is a trait or a lifetime.
TraitObject(#[visitable(extra = BoundKind::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, #[visitable(extra = BoundKind::Impl)] GenericBounds),
/// No-op; kept solely so that we can pretty-print faithfully.
Paren(Box<Ty>),
/// 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(Box<MacCall>),
/// Placeholder for a `va_list`.
CVarArgs,
/// Pattern types like `pattern_type!(u32 is 1..=)`, which is the same as `NonZero<u32>`,
/// just as part of the type system.
Pat(Box<Ty>, Box<TyPat>),
/// A `field_of` expression (e.g., `builtin # field_of(Struct, field)`).
///
/// Usually not written directly in user code but indirectly via the macro
/// `core::field::field_of!(...)`.
FieldOf(Box<Ty>, Option<Ident>, Ident),
/// Sometimes we need a dummy value when no error has occurred.
Dummy,
/// Placeholder for a kind that has failed to be defined.
Err(ErrorGuaranteed),
}
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())
}
pub fn is_simple_path(&self) -> Option<Symbol> {
if let TyKind::Path(None, Path { segments, .. }) = &self
&& let [segment] = &segments[..]
&& segment.args.is_none()
{
Some(segment.ident.name)
} else {
None
}
}
/// Returns `true` if this type is considered a scalar primitive (e.g.,
/// `i32`, `u8`, `bool`, etc).
///
/// This check is based on **symbol equality** and does **not** remove any
/// path prefixes or references. If a type alias or shadowing is present
/// (e.g., `type i32 = CustomType;`), this method will still return `true`
/// for `i32`, even though it may not refer to the primitive type.
pub fn maybe_scalar(&self) -> bool {
let Some(ty_sym) = self.is_simple_path() else {
// unit type
return self.is_unit();
};
matches!(
ty_sym,
sym::i8
| sym::i16
| sym::i32
| sym::i64
| sym::i128
| sym::u8
| sym::u16
| sym::u32
| sym::u64
| sym::u128
| sym::f16
| sym::f32
| sym::f64
| sym::f128
| sym::char
| sym::bool
)
}
}
/// A pattern type pattern.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct TyPat {
pub id: NodeId,
pub kind: TyPatKind,
pub span: Span,
pub tokens: Option<LazyAttrTokenStream>,
}
/// All the different flavors of pattern that Rust recognizes.
//
// Adding a new variant? Please update `test_pat` in `tests/ui/macros/stringify.rs`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum TyPatKind {
/// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
Range(Option<Box<AnonConst>>, Option<Box<AnonConst>>, Spanned<RangeEnd>),
/// A `!null` pattern for raw pointers.
NotNull,
Or(ThinVec<TyPat>),
/// Placeholder for a pattern that wasn't syntactically well formed in some way.
Err(ErrorGuaranteed),
}
/// Syntax used to declare a trait object.
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic, Walkable)]
#[repr(u8)]
pub enum TraitObjectSyntax {
// SAFETY: When adding new variants make sure to update the `Tag` impl.
Dyn = 0,
None = 1,
}
/// SAFETY: `TraitObjectSyntax` only has 3 data-less variants which means
/// it can be represented with a `u2`. We use `repr(u8)` to guarantee the
/// discriminants of the variants are no greater than `3`.
unsafe impl Tag for TraitObjectSyntax {
const BITS: u32 = 2;
fn into_usize(self) -> usize {
self as u8 as usize
}
unsafe fn from_usize(tag: usize) -> Self {
match tag {
0 => TraitObjectSyntax::Dyn,
1 => TraitObjectSyntax::None,
_ => unreachable!(),
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum PreciseCapturingArg {
/// Lifetime parameter.
Lifetime(#[visitable(extra = LifetimeCtxt::GenericArg)] Lifetime),
/// Type or const parameter.
Arg(Path, NodeId),
}
/// 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, Walkable)]
pub enum InlineAsmRegOrRegClass {
Reg(Symbol),
RegClass(Symbol),
}
#[derive(Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
pub struct InlineAsmOptions(u16);
bitflags::bitflags! {
impl 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;
}
}
impl InlineAsmOptions {
pub const COUNT: usize = Self::all().bits().count_ones() as usize;
pub const GLOBAL_OPTIONS: Self = Self::ATT_SYNTAX.union(Self::RAW);
pub const NAKED_OPTIONS: Self = Self::ATT_SYNTAX.union(Self::RAW);
pub fn human_readable_names(&self) -> Vec<&'static str> {
let mut options = vec![];
if self.contains(InlineAsmOptions::PURE) {
options.push("pure");
}
if self.contains(InlineAsmOptions::NOMEM) {
options.push("nomem");
}
if self.contains(InlineAsmOptions::READONLY) {
options.push("readonly");
}
if self.contains(InlineAsmOptions::PRESERVES_FLAGS) {
options.push("preserves_flags");
}
if self.contains(InlineAsmOptions::NORETURN) {
options.push("noreturn");
}
if self.contains(InlineAsmOptions::NOSTACK) {
options.push("nostack");
}
if self.contains(InlineAsmOptions::ATT_SYNTAX) {
options.push("att_syntax");
}
if self.contains(InlineAsmOptions::RAW) {
options.push("raw");
}
if self.contains(InlineAsmOptions::MAY_UNWIND) {
options.push("may_unwind");
}
options
}
}
impl std::fmt::Debug for InlineAsmOptions {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
bitflags::parser::to_writer(self, f)
}
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Hash, HashStable_Generic, Walkable)]
pub enum InlineAsmTemplatePiece {
String(Cow<'static, str>),
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, Walkable)]
pub struct InlineAsmSym {
pub id: NodeId,
pub qself: Option<Box<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, Walkable)]
pub enum InlineAsmOperand {
In {
reg: InlineAsmRegOrRegClass,
expr: Box<Expr>,
},
Out {
reg: InlineAsmRegOrRegClass,
late: bool,
expr: Option<Box<Expr>>,
},
InOut {
reg: InlineAsmRegOrRegClass,
late: bool,
expr: Box<Expr>,
},
SplitInOut {
reg: InlineAsmRegOrRegClass,
late: bool,
in_expr: Box<Expr>,
out_expr: Option<Box<Expr>>,
},
Const {
anon_const: AnonConst,
},
Sym {
sym: InlineAsmSym,
},
Label {
block: Box<Block>,
},
}
impl InlineAsmOperand {
pub fn reg(&self) -> Option<&InlineAsmRegOrRegClass> {
match self {
Self::In { reg, .. }
| Self::Out { reg, .. }
| Self::InOut { reg, .. }
| Self::SplitInOut { reg, .. } => Some(reg),
Self::Const { .. } | Self::Sym { .. } | Self::Label { .. } => None,
}
}
}
#[derive(Clone, Copy, Encodable, Decodable, Debug, HashStable_Generic, Walkable, PartialEq, Eq)]
pub enum AsmMacro {
/// The `asm!` macro
Asm,
/// The `global_asm!` macro
GlobalAsm,
/// The `naked_asm!` macro
NakedAsm,
}
impl AsmMacro {
pub const fn macro_name(self) -> &'static str {
match self {
AsmMacro::Asm => "asm",
AsmMacro::GlobalAsm => "global_asm",
AsmMacro::NakedAsm => "naked_asm",
}
}
pub const fn is_supported_option(self, option: InlineAsmOptions) -> bool {
match self {
AsmMacro::Asm => true,
AsmMacro::GlobalAsm => InlineAsmOptions::GLOBAL_OPTIONS.contains(option),
AsmMacro::NakedAsm => InlineAsmOptions::NAKED_OPTIONS.contains(option),
}
}
pub const fn diverges(self, options: InlineAsmOptions) -> bool {
match self {
AsmMacro::Asm => options.contains(InlineAsmOptions::NORETURN),
AsmMacro::GlobalAsm => true,
AsmMacro::NakedAsm => true,
}
}
}
/// Inline assembly.
///
/// E.g., `asm!("NOP");`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct InlineAsm {
pub asm_macro: AsmMacro,
pub template: Vec<InlineAsmTemplatePiece>,
pub template_strs: Box<[(Symbol, Option<Symbol>, Span)]>,
pub operands: Vec<(InlineAsmOperand, Span)>,
pub clobber_abis: Vec<(Symbol, Span)>,
#[visitable(ignore)]
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, Walkable)]
pub struct Param {
pub attrs: AttrVec,
pub ty: Box<Ty>,
pub pat: Box<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),
/// `&'lt pin const self`, `&'lt pin mut self`
Pinned(Option<Lifetime>, Mutability),
/// `self: TYPE`, `mut self: TYPE`
Explicit(Box<Ty>, Mutability),
}
impl SelfKind {
pub fn to_ref_suggestion(&self) -> String {
match self {
SelfKind::Region(None, mutbl) => mutbl.ref_prefix_str().to_string(),
SelfKind::Region(Some(lt), mutbl) => format!("&{lt} {}", mutbl.prefix_str()),
SelfKind::Pinned(None, mutbl) => format!("&pin {}", mutbl.ptr_str()),
SelfKind::Pinned(Some(lt), mutbl) => format!("&{lt} pin {}", mutbl.ptr_str()),
SelfKind::Value(_) | SelfKind::Explicit(_, _) => {
unreachable!("if we had an explicit self, we wouldn't be here")
}
}
}
}
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(ByRef::No, 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::Ref(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
}
TyKind::PinnedRef(lt, MutTy { ref ty, mutbl })
if ty.kind.is_implicit_self() =>
{
Some(respan(self.pat.span, SelfKind::Pinned(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 = Box::new(Ty {
id: DUMMY_NODE_ID,
kind: TyKind::ImplicitSelf,
span: eself_ident.span,
tokens: None,
});
let (mutbl, ty) = match eself.node {
SelfKind::Explicit(ty, mutbl) => (mutbl, ty),
SelfKind::Value(mutbl) => (mutbl, infer_ty),
SelfKind::Region(lt, mutbl) => (
Mutability::Not,
Box::new(Ty {
id: DUMMY_NODE_ID,
kind: TyKind::Ref(lt, MutTy { ty: infer_ty, mutbl }),
span,
tokens: None,
}),
),
SelfKind::Pinned(lt, mutbl) => (
mutbl,
Box::new(Ty {
id: DUMMY_NODE_ID,
kind: TyKind::PinnedRef(lt, MutTy { ty: infer_ty, mutbl }),
span,
tokens: None,
}),
),
};
Param {
attrs,
pat: Box::new(Pat {
id: DUMMY_NODE_ID,
kind: PatKind::Ident(BindingMode(ByRef::No, mutbl), eself_ident, None),
span,
tokens: None,
}),
span,
ty,
id: DUMMY_NODE_ID,
is_placeholder: false,
}
}
}
/// 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, Walkable)]
pub struct FnDecl {
pub inputs: ThinVec<Param>,
pub output: FnRetTy,
}
impl FnDecl {
pub fn has_self(&self) -> bool {
self.inputs.get(0).is_some_and(Param::is_self)
}
pub fn c_variadic(&self) -> bool {
self.inputs.last().is_some_and(|arg| matches!(arg.ty.kind, TyKind::CVarArgs))
}
}
/// Is the trait definition an auto trait?
#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic, Walkable)]
pub enum IsAuto {
Yes,
No,
}
/// Safety of items.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
#[derive(HashStable_Generic, Walkable)]
pub enum Safety {
/// `unsafe` an item is explicitly marked as `unsafe`.
Unsafe(Span),
/// `safe` an item is explicitly marked as `safe`.
Safe(Span),
/// Default means no value was provided, it will take a default value given the context in
/// which is used.
Default,
}
/// Describes what kind of coroutine markers, if any, a function has.
///
/// Coroutine markers are things that cause the function to generate a coroutine, such as `async`,
/// which makes the function return `impl Future`, or `gen`, which makes the function return `impl
/// Iterator`.
#[derive(Copy, Clone, Encodable, Decodable, Debug, Walkable)]
pub enum CoroutineKind {
/// `async`, which returns an `impl Future`.
Async { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
/// `gen`, which returns an `impl Iterator`.
Gen { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
/// `async gen`, which returns an `impl AsyncIterator`.
AsyncGen { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
}
impl CoroutineKind {
pub fn span(self) -> Span {
match self {
CoroutineKind::Async { span, .. } => span,
CoroutineKind::Gen { span, .. } => span,
CoroutineKind::AsyncGen { span, .. } => span,
}
}
pub fn as_str(self) -> &'static str {
match self {
CoroutineKind::Async { .. } => "async",
CoroutineKind::Gen { .. } => "gen",
CoroutineKind::AsyncGen { .. } => "async gen",
}
}
pub fn closure_id(self) -> NodeId {
match self {
CoroutineKind::Async { closure_id, .. }
| CoroutineKind::Gen { closure_id, .. }
| CoroutineKind::AsyncGen { closure_id, .. } => closure_id,
}
}
/// In this case this is an `async` or `gen` return, the `NodeId` for the generated `impl Trait`
/// item.
pub fn return_id(self) -> (NodeId, Span) {
match self {
CoroutineKind::Async { return_impl_trait_id, span, .. }
| CoroutineKind::Gen { return_impl_trait_id, span, .. }
| CoroutineKind::AsyncGen { return_impl_trait_id, span, .. } => {
(return_impl_trait_id, span)
}
}
}
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
#[derive(HashStable_Generic, Walkable)]
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, Walkable)]
pub enum Defaultness {
/// Item is unmarked. Implicitly determined based off of position.
/// For impls, this is `final`; for traits, this is `default`.
///
/// If you're expanding an item in a built-in macro or parsing an item
/// by hand, you probably want to use this.
Implicit,
/// `default`
Default(Span),
/// `final`; per RFC 3678, only trait items may be *explicitly* marked final.
Final(Span),
}
#[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic, Walkable)]
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),
}
}
}
/// The polarity of a trait bound.
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, Hash)]
#[derive(HashStable_Generic, Walkable)]
pub enum BoundPolarity {
/// `Type: Trait`
Positive,
/// `Type: !Trait`
Negative(Span),
/// `Type: ?Trait`
Maybe(Span),
}
impl BoundPolarity {
pub fn as_str(self) -> &'static str {
match self {
Self::Positive => "",
Self::Negative(_) => "!",
Self::Maybe(_) => "?",
}
}
}
/// The constness of a trait bound.
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, Hash)]
#[derive(HashStable_Generic, Walkable)]
pub enum BoundConstness {
/// `Type: Trait`
Never,
/// `Type: const Trait`
Always(Span),
/// `Type: [const] Trait`
Maybe(Span),
}
impl BoundConstness {
pub fn as_str(self) -> &'static str {
match self {
Self::Never => "",
Self::Always(_) => "const",
Self::Maybe(_) => "[const]",
}
}
}
/// The asyncness of a trait bound.
#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
#[derive(HashStable_Generic, Walkable)]
pub enum BoundAsyncness {
/// `Type: Trait`
Normal,
/// `Type: async Trait`
Async(Span),
}
impl BoundAsyncness {
pub fn as_str(self) -> &'static str {
match self {
Self::Normal => "",
Self::Async(_) => "async",
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
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(Box<Ty>),
}
impl FnRetTy {
pub fn span(&self) -> Span {
match self {
&FnRetTy::Default(span) => span,
FnRetTy::Ty(ty) => ty.span,
}
}
}
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, Walkable)]
pub enum Inline {
Yes,
No { had_parse_error: Result<(), ErrorGuaranteed> },
}
/// Module item kind.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
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(ThinVec<Box<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, Default, Walkable)]
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,
}
/// Foreign module declaration.
///
/// E.g., `extern { .. }` or `extern "C" { .. }`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct ForeignMod {
/// Span of the `extern` keyword.
pub extern_span: Span,
/// `unsafe` keyword accepted syntactically for macro DSLs, but not
/// semantically by Rust.
pub safety: Safety,
pub abi: Option<StrLit>,
pub items: ThinVec<Box<ForeignItem>>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct EnumDef {
pub variants: ThinVec<Variant>,
}
/// Enum variant.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
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, Walkable)]
pub enum UseTreeKind {
/// `use prefix` or `use prefix as rename`
Simple(Option<Ident>),
/// `use prefix::{...}`
///
/// The span represents the braces of the nested group and all elements within:
///
/// ```text
/// use foo::{bar, baz};
/// ^^^^^^^^^^
/// ```
Nested { items: ThinVec<(UseTree, NodeId)>, span: Span },
/// `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, Walkable)]
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, Eq, Hash, Debug, Copy)]
#[derive(Encodable, Decodable, HashStable_Generic, Walkable)]
pub enum AttrStyle {
Outer,
Inner,
}
/// A list of attributes.
pub type AttrVec = ThinVec<Attribute>;
/// A syntax-level representation of an attribute.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
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, Walkable)]
pub enum AttrKind {
/// A normal attribute.
Normal(Box<NormalAttr>),
/// 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),
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct NormalAttr {
pub item: AttrItem,
// Tokens for the full attribute, e.g. `#[foo]`, `#![bar]`.
pub tokens: Option<LazyAttrTokenStream>,
}
impl NormalAttr {
pub fn from_ident(ident: Ident) -> Self {
Self {
item: AttrItem {
unsafety: Safety::Default,
path: Path::from_ident(ident),
args: AttrItemKind::Unparsed(AttrArgs::Empty),
tokens: None,
},
tokens: None,
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct AttrItem {
pub unsafety: Safety,
pub path: Path,
pub args: AttrItemKind,
// Tokens for the meta item, e.g. just the `foo` within `#[foo]` or `#![foo]`.
pub tokens: Option<LazyAttrTokenStream>,
}
/// Some attributes are stored in a parsed form, for performance reasons.
/// Their arguments don't have to be reparsed everytime they're used
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum AttrItemKind {
Parsed(EarlyParsedAttribute),
Unparsed(AttrArgs),
}
impl AttrItemKind {
pub fn unparsed(self) -> Option<AttrArgs> {
match self {
AttrItemKind::Unparsed(args) => Some(args),
AttrItemKind::Parsed(_) => None,
}
}
pub fn unparsed_ref(&self) -> Option<&AttrArgs> {
match self {
AttrItemKind::Unparsed(args) => Some(args),
AttrItemKind::Parsed(_) => None,
}
}
pub fn span(&self) -> Option<Span> {
match self {
AttrItemKind::Unparsed(args) => args.span(),
AttrItemKind::Parsed(_) => None,
}
}
}
/// Some attributes are stored in parsed form in the AST.
/// This is done for performance reasons, so the attributes don't need to be reparsed on every use.
///
/// Currently all early parsed attributes are excluded from pretty printing at rustc_ast_pretty::pprust::state::print_attribute_inline.
/// When adding new early parsed attributes, consider whether they should be pretty printed.
#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum EarlyParsedAttribute {
CfgTrace(CfgEntry),
CfgAttrTrace,
}
impl AttrItem {
pub fn is_valid_for_outer_style(&self) -> bool {
self.path == sym::cfg_attr
|| self.path == sym::cfg
|| self.path == sym::forbid
|| self.path == sym::warn
|| self.path == sym::allow
|| self.path == sym::deny
}
}
/// `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, Walkable)]
pub struct TraitRef {
pub path: Path,
pub ref_id: NodeId,
}
/// Whether enclosing parentheses are present or not.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum Parens {
Yes,
No,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct PolyTraitRef {
/// The `'a` in `for<'a> Foo<&'a T>`.
pub bound_generic_params: ThinVec<GenericParam>,
// Optional constness, asyncness, or polarity.
pub modifiers: TraitBoundModifiers,
/// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
pub trait_ref: TraitRef,
pub span: Span,
/// When `Yes`, the first and last character of `span` are an opening
/// and a closing paren respectively.
pub parens: Parens,
}
impl PolyTraitRef {
pub fn new(
generic_params: ThinVec<GenericParam>,
path: Path,
modifiers: TraitBoundModifiers,
span: Span,
parens: Parens,
) -> Self {
PolyTraitRef {
bound_generic_params: generic_params,
modifiers,
trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
span,
parens,
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Visibility {
pub kind: VisibilityKind,
pub span: Span,
pub tokens: Option<LazyAttrTokenStream>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum VisibilityKind {
Public,
Restricted { path: Box<Path>, id: NodeId, shorthand: bool },
Inherited,
}
impl VisibilityKind {
pub fn is_pub(&self) -> bool {
matches!(self, VisibilityKind::Public)
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct ImplRestriction {
pub kind: RestrictionKind,
pub span: Span,
pub tokens: Option<LazyAttrTokenStream>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum RestrictionKind {
Unrestricted,
Restricted { path: Box<Path>, id: NodeId, shorthand: bool },
}
/// Field definition in a struct, variant or union.
///
/// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct FieldDef {
pub attrs: AttrVec,
pub id: NodeId,
pub span: Span,
pub vis: Visibility,
pub safety: Safety,
pub ident: Option<Ident>,
pub ty: Box<Ty>,
pub default: Option<AnonConst>,
pub is_placeholder: bool,
}
/// Was parsing recovery performed?
#[derive(Copy, Clone, Debug, Encodable, Decodable, HashStable_Generic, Walkable)]
pub enum Recovered {
No,
Yes(ErrorGuaranteed),
}
/// Fields and constructor ids of enum variants and structs.
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum VariantData {
/// Struct variant.
///
/// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
Struct { fields: ThinVec<FieldDef>, recovered: Recovered },
/// Tuple variant.
///
/// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
Tuple(ThinVec<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 { fields, .. } | VariantData::Tuple(fields, _) => fields,
_ => &[],
}
}
/// Return the `NodeId` of this variant's constructor, if it has one.
pub fn ctor_node_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: AttrVec,
pub id: NodeId,
pub span: Span,
pub vis: Visibility,
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<LazyAttrTokenStream>,
}
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))
}
pub fn opt_generics(&self) -> Option<&Generics> {
match &self.kind {
ItemKind::ExternCrate(..)
| ItemKind::ConstBlock(_)
| ItemKind::Use(_)
| ItemKind::Mod(..)
| ItemKind::ForeignMod(_)
| ItemKind::GlobalAsm(_)
| ItemKind::MacCall(_)
| ItemKind::Delegation(_)
| ItemKind::DelegationMac(_)
| ItemKind::MacroDef(..) => None,
ItemKind::Static(_) => None,
ItemKind::Const(i) => Some(&i.generics),
ItemKind::Fn(i) => Some(&i.generics),
ItemKind::TyAlias(i) => Some(&i.generics),
ItemKind::TraitAlias(i) => Some(&i.generics),
ItemKind::Enum(_, generics, _)
| ItemKind::Struct(_, generics, _)
| ItemKind::Union(_, generics, _) => Some(&generics),
ItemKind::Trait(i) => Some(&i.generics),
ItemKind::Impl(i) => Some(&i.generics),
}
}
}
/// `extern` qualifier on a function item or function type.
#[derive(Clone, Copy, Encodable, Decodable, Debug, Walkable)]
pub enum Extern {
/// No explicit extern keyword was used.
///
/// E.g. `fn foo() {}`.
None,
/// An explicit extern keyword was used, but with implicit ABI.
///
/// E.g. `extern fn foo() {}`.
///
/// This is just `extern "C"` (see `rustc_abi::ExternAbi::FALLBACK`).
Implicit(Span),
/// An explicit extern keyword was used with an explicit ABI.
///
/// E.g. `extern "C" fn foo() {}`.
Explicit(StrLit, Span),
}
impl Extern {
pub fn from_abi(abi: Option<StrLit>, span: Span) -> Extern {
match abi {
Some(name) => Extern::Explicit(name, span),
None => Extern::Implicit(span),
}
}
pub fn span(self) -> Option<Span> {
match self {
Extern::None => None,
Extern::Implicit(span) | Extern::Explicit(_, span) => Some(span),
}
}
}
/// 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, Walkable)]
pub struct FnHeader {
/// The `const` keyword, if any
pub constness: Const,
/// Whether this is `async`, `gen`, or nothing.
pub coroutine_kind: Option<CoroutineKind>,
/// Whether this is `unsafe`, or has a default safety.
pub safety: Safety,
/// The `extern` keyword and corresponding ABI string, if any.
pub ext: Extern,
}
impl FnHeader {
/// Does this function header have any qualifiers or is it empty?
pub fn has_qualifiers(&self) -> bool {
let Self { safety, coroutine_kind, constness, ext } = self;
matches!(safety, Safety::Unsafe(_))
|| coroutine_kind.is_some()
|| matches!(constness, Const::Yes(_))
|| !matches!(ext, Extern::None)
}
}
impl Default for FnHeader {
fn default() -> FnHeader {
FnHeader {
safety: Safety::Default,
coroutine_kind: None,
constness: Const::No,
ext: Extern::None,
}
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct TraitAlias {
pub constness: Const,
pub ident: Ident,
pub generics: Generics,
#[visitable(extra = BoundKind::Bound)]
pub bounds: GenericBounds,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Trait {
pub constness: Const,
pub safety: Safety,
pub is_auto: IsAuto,
pub impl_restriction: ImplRestriction,
pub ident: Ident,
pub generics: Generics,
#[visitable(extra = BoundKind::SuperTraits)]
pub bounds: GenericBounds,
#[visitable(extra = AssocCtxt::Trait)]
pub items: ThinVec<Box<AssocItem>>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct TyAlias {
pub defaultness: Defaultness,
pub ident: Ident,
pub generics: Generics,
/// There are two locations for where clause on type aliases. This represents the second
/// where clause, before the semicolon. The first where clause is stored inside `generics`.
///
/// 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;
/// // ^^^^^^^^^^^^^^ before where clause
/// // ^^^^^^^^^^^^^^ after where clause
/// }
/// ```
pub after_where_clause: WhereClause,
#[visitable(extra = BoundKind::Bound)]
pub bounds: GenericBounds,
pub ty: Option<Box<Ty>>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Impl {
pub generics: Generics,
pub constness: Const,
pub of_trait: Option<Box<TraitImplHeader>>,
pub self_ty: Box<Ty>,
pub items: ThinVec<Box<AssocItem>>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct TraitImplHeader {
pub defaultness: Defaultness,
pub safety: Safety,
pub polarity: ImplPolarity,
pub trait_ref: TraitRef,
}
#[derive(Clone, Encodable, Decodable, Debug, Default, Walkable)]
pub struct FnContract {
/// Declarations of variables accessible both in the `requires` and
/// `ensures` clauses.
pub declarations: ThinVec<Stmt>,
pub requires: Option<Box<Expr>>,
pub ensures: Option<Box<Expr>>,
}
#[derive(Clone, Encodable, Decodable, Debug)]
pub struct Fn {
pub defaultness: Defaultness,
pub ident: Ident,
pub generics: Generics,
pub sig: FnSig,
pub contract: Option<Box<FnContract>>,
pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
pub body: Option<Box<Block>>,
/// This function is an implementation of an externally implementable item (EII).
/// This means, there was an EII declared somewhere and this function is the
/// implementation that should be run when the declaration is called.
pub eii_impls: ThinVec<EiiImpl>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct EiiImpl {
pub node_id: NodeId,
pub eii_macro_path: Path,
/// This field is an implementation detail that prevents a lot of bugs.
/// See <https://github.com/rust-lang/rust/issues/149981> for an example.
///
/// The problem is, that if we generate a declaration *together* with its default,
/// we generate both a declaration and an implementation. The generated implementation
/// uses the same mechanism to register itself as a user-defined implementation would,
/// despite being invisible to users. What does happen is a name resolution step.
/// The invisible default implementation has to find the declaration.
/// Both are generated at the same time, so we can skip that name resolution step.
///
/// This field is that shortcut: we prefill the extern target to skip a name resolution step,
/// making sure it never fails. It'd be awful UX if we fail name resolution in code invisible to the user.
pub known_eii_macro_resolution: Option<EiiDecl>,
pub impl_safety: Safety,
pub span: Span,
pub inner_span: Span,
pub is_default: bool,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Delegation {
/// Path resolution id.
pub id: NodeId,
pub qself: Option<Box<QSelf>>,
pub path: Path,
pub ident: Ident,
pub rename: Option<Ident>,
pub body: Option<Box<Block>>,
/// The item was expanded from a glob delegation item.
pub from_glob: bool,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct DelegationMac {
pub qself: Option<Box<QSelf>>,
pub prefix: Path,
// Some for list delegation, and None for glob delegation.
pub suffixes: Option<ThinVec<(Ident, Option<Ident>)>>,
pub body: Option<Box<Block>>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct StaticItem {
pub ident: Ident,
pub ty: Box<Ty>,
pub safety: Safety,
pub mutability: Mutability,
pub expr: Option<Box<Expr>>,
pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct ConstItem {
pub defaultness: Defaultness,
pub ident: Ident,
pub generics: Generics,
pub ty: Box<Ty>,
pub rhs_kind: ConstItemRhsKind,
pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub enum ConstItemRhsKind {
Body { rhs: Option<Box<Expr>> },
TypeConst { rhs: Option<AnonConst> },
}
impl ConstItemRhsKind {
pub fn new_body(rhs: Box<Expr>) -> Self {
Self::Body { rhs: Some(rhs) }
}
pub fn span(&self) -> Option<Span> {
Some(self.expr()?.span)
}
pub fn expr(&self) -> Option<&Expr> {
match self {
Self::Body { rhs: Some(body) } => Some(&body),
Self::TypeConst { rhs: Some(anon) } => Some(&anon.value),
_ => None,
}
}
pub fn has_expr(&self) -> bool {
match self {
Self::Body { rhs: Some(_) } => true,
Self::TypeConst { rhs: Some(_) } => true,
_ => false,
}
}
pub fn is_type_const(&self) -> bool {
matches!(self, &Self::TypeConst { .. })
}
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct ConstBlockItem {
pub id: NodeId,
pub span: Span,
pub block: Box<Block>,
}
impl ConstBlockItem {
pub const IDENT: Ident = Ident { name: kw::Underscore, span: DUMMY_SP };
}
#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
pub struct Guard {
pub cond: Expr,
pub span_with_leading_if: Span,
}
impl Guard {
pub fn span(&self) -> Span {
self.cond.span
}
}
// Adding a new variant? Please update `test_item` in `tests/ui/macros/stringify.rs`.
#[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>, Ident),
/// 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(Box<StaticItem>),
/// A constant item (`const`).
///
/// E.g., `const FOO: i32 = 42;`.
Const(Box<ConstItem>),
/// A module-level const block.
/// Equivalent to `const _: () = const { ... };`.
///
/// E.g., `const { assert!(true) }`.
ConstBlock(ConstBlockItem),
/// 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(Safety, Ident, 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(Ident, Generics, EnumDef),
/// A struct definition (`struct`).
///
/// E.g., `struct Foo<A> { x: A }`.
Struct(Ident, Generics, VariantData),
/// A union definition (`union`).
///
/// E.g., `union Foo<A, B> { x: A, y: B }`.
Union(Ident, Generics, VariantData),
/// 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(Box<TraitAlias>),
/// An implementation.
///
/// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
Impl(Impl),
/// A macro invocation.
///
/// E.g., `foo!(..)`.
MacCall(Box<MacCall>),
/// A macro definition.
MacroDef(Ident, MacroDef),
/// A single delegation item (`reuse`).
///
/// E.g. `reuse <Type as Trait>::name { target_expr_template }`.
Delegation(Box<Delegation>),
/// A list or glob delegation item (`reuse prefix::{a, b, c}`, `reuse prefix::*`).
/// Treated similarly to a macro call and expanded early.
DelegationMac(Box<DelegationMac>),
}
impl ItemKind {
pub fn ident(&self) -> Option<Ident> {
match *self {
ItemKind::ExternCrate(_, ident)
| ItemKind::Static(box StaticItem { ident, .. })
| ItemKind::Const(box ConstItem { ident, .. })
| ItemKind::Fn(box Fn { ident, .. })
| ItemKind::Mod(_, ident, _)
| ItemKind::TyAlias(box TyAlias { ident, .. })
| ItemKind::Enum(ident, ..)
| ItemKind::Struct(ident, ..)
| ItemKind::Union(ident, ..)
| ItemKind::Trait(box Trait { ident, .. })
| ItemKind::TraitAlias(box TraitAlias { ident, .. })
| ItemKind::MacroDef(ident, _)
| ItemKind::Delegation(box Delegation { ident, .. }) => Some(ident),
ItemKind::ConstBlock(_) => Some(ConstBlockItem::IDENT),
ItemKind::Use(_)
| ItemKind::ForeignMod(_)
| ItemKind::GlobalAsm(_)
| ItemKind::Impl(_)
| ItemKind::MacCall(_)
| ItemKind::DelegationMac(_) => None,
}
}
/// "a" or "an"
pub fn article(&self) -> &'static str {
use ItemKind::*;
match self {
Use(..) | Static(..) | Const(..) | ConstBlock(..) | Fn(..) | Mod(..)
| GlobalAsm(..) | TyAlias(..) | Struct(..) | Union(..) | Trait(..) | TraitAlias(..)
| MacroDef(..) | Delegation(..) | DelegationMac(..) => "a",
ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
}
}
pub fn descr(&self) -> &'static str {
match self {
ItemKind::ExternCrate(..) => "extern crate",
ItemKind::Use(..) => "`use` import",
ItemKind::Static(..) => "static item",
ItemKind::Const(..) => "constant item",
ItemKind::ConstBlock(..) => "const block",
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",
ItemKind::Delegation(..) => "delegated function",
ItemKind::DelegationMac(..) => "delegation",
}
}
pub fn generics(&self) -> Option<&Generics> {
match self {
Self::Fn(box Fn { generics, .. })
| Self::TyAlias(box TyAlias { generics, .. })
| Self::Const(box ConstItem { generics, .. })
| Self::Enum(_, generics, _)
| Self::Struct(_, generics, _)
| Self::Union(_, generics, _)
| Self::Trait(box Trait { generics, .. })
| Self::TraitAlias(box TraitAlias { generics, .. })
| Self::Impl(Impl { generics, .. }) => Some(generics),
Self::ExternCrate(..)
| Self::Use(..)
| Self::Static(..)
| Self::ConstBlock(..)
| Self::Mod(..)
| Self::ForeignMod(..)
| Self::GlobalAsm(..)
| Self::MacCall(..)
| Self::MacroDef(..)
| Self::Delegation(..)
| Self::DelegationMac(..) => 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(Box<ConstItem>),
/// An associated function.
Fn(Box<Fn>),
/// An associated type.
Type(Box<TyAlias>),
/// A macro expanding to associated items.
MacCall(Box<MacCall>),
/// An associated delegation item.
Delegation(Box<Delegation>),
/// An associated list or glob delegation item.
DelegationMac(Box<DelegationMac>),
}
impl AssocItemKind {
pub fn ident(&self) -> Option<Ident> {
match *self {
AssocItemKind::Const(box ConstItem { ident, .. })
| AssocItemKind::Fn(box Fn { ident, .. })
| AssocItemKind::Type(box TyAlias { ident, .. })
| AssocItemKind::Delegation(box Delegation { ident, .. }) => Some(ident),
AssocItemKind::MacCall(_) | AssocItemKind::DelegationMac(_) => None,
}
}
pub fn defaultness(&self) -> Defaultness {
match *self {
Self::Const(box ConstItem { defaultness, .. })
| Self::Fn(box Fn { defaultness, .. })
| Self::Type(box TyAlias { defaultness, .. }) => defaultness,
Self::MacCall(..) | Self::Delegation(..) | Self::DelegationMac(..) => {
Defaultness::Implicit
}
}
}
}
impl From<AssocItemKind> for ItemKind {
fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
match assoc_item_kind {
AssocItemKind::Const(item) => ItemKind::Const(item),
AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
AssocItemKind::Type(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
AssocItemKind::Delegation(delegation) => ItemKind::Delegation(delegation),
AssocItemKind::DelegationMac(delegation) => ItemKind::DelegationMac(delegation),
}
}
}
impl TryFrom<ItemKind> for AssocItemKind {
type Error = ItemKind;
fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
Ok(match item_kind {
ItemKind::Const(item) => AssocItemKind::Const(item),
ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
ItemKind::TyAlias(ty_kind) => AssocItemKind::Type(ty_kind),
ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
ItemKind::Delegation(d) => AssocItemKind::Delegation(d),
ItemKind::DelegationMac(d) => AssocItemKind::DelegationMac(d),
_ => 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(Box<StaticItem>),
/// A foreign function.
Fn(Box<Fn>),
/// A foreign type.
TyAlias(Box<TyAlias>),
/// A macro expanding to foreign items.
MacCall(Box<MacCall>),
}
impl ForeignItemKind {
pub fn ident(&self) -> Option<Ident> {
match *self {
ForeignItemKind::Static(box StaticItem { ident, .. })
| ForeignItemKind::Fn(box Fn { ident, .. })
| ForeignItemKind::TyAlias(box TyAlias { ident, .. }) => Some(ident),
ForeignItemKind::MacCall(_) => None,
}
}
}
impl From<ForeignItemKind> for ItemKind {
fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
match foreign_item_kind {
ForeignItemKind::Static(static_foreign_item) => ItemKind::Static(static_foreign_item),
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(static_item) => ForeignItemKind::Static(static_item),
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>;
// Some nodes are used a lot. Make sure they don't unintentionally get bigger.
#[cfg(target_pointer_width = "64")]
mod size_asserts {
use rustc_data_structures::static_assert_size;
use super::*;
// tidy-alphabetical-start
static_assert_size!(AssocItem, 80);
static_assert_size!(AssocItemKind, 16);
static_assert_size!(Attribute, 32);
static_assert_size!(Block, 32);
static_assert_size!(Expr, 72);
static_assert_size!(ExprKind, 40);
static_assert_size!(Fn, 192);
static_assert_size!(ForeignItem, 80);
static_assert_size!(ForeignItemKind, 16);
static_assert_size!(GenericArg, 24);
static_assert_size!(GenericBound, 88);
static_assert_size!(Generics, 40);
static_assert_size!(Impl, 80);
static_assert_size!(Item, 152);
static_assert_size!(ItemKind, 88);
static_assert_size!(LitKind, 24);
static_assert_size!(Local, 96);
static_assert_size!(MetaItemLit, 40);
static_assert_size!(Param, 40);
static_assert_size!(Pat, 80);
static_assert_size!(PatKind, 56);
static_assert_size!(Path, 24);
static_assert_size!(PathSegment, 24);
static_assert_size!(Stmt, 32);
static_assert_size!(StmtKind, 16);
static_assert_size!(TraitImplHeader, 72);
static_assert_size!(Ty, 64);
static_assert_size!(TyKind, 40);
// tidy-alphabetical-end
}