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use std::borrow::Cow;
use std::fmt;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::Lrc;
use rustc_macros::{Decodable, Encodable, HashStable_Generic};
use rustc_span::edition::Edition;
use rustc_span::symbol::{kw, sym};
#[allow(clippy::useless_attribute)] // FIXME: following use of `hidden_glob_reexports` incorrectly triggers `useless_attribute` lint.
#[allow(hidden_glob_reexports)]
use rustc_span::symbol::{Ident, Symbol};
use rustc_span::{ErrorGuaranteed, Span, DUMMY_SP};
pub use BinOpToken::*;
pub use LitKind::*;
pub use Nonterminal::*;
pub use NtExprKind::*;
pub use NtPatKind::*;
pub use TokenKind::*;
use crate::ast;
use crate::ptr::P;
use crate::util::case::Case;
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum CommentKind {
Line,
Block,
}
#[derive(Clone, PartialEq, Encodable, Decodable, Hash, Debug, Copy)]
#[derive(HashStable_Generic)]
pub enum BinOpToken {
Plus,
Minus,
Star,
Slash,
Percent,
Caret,
And,
Or,
Shl,
Shr,
}
/// Describes how a sequence of token trees is delimited.
/// Cannot use `proc_macro::Delimiter` directly because this
/// structure should implement some additional traits.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[derive(Encodable, Decodable, Hash, HashStable_Generic)]
pub enum Delimiter {
/// `( ... )`
Parenthesis,
/// `{ ... }`
Brace,
/// `[ ... ]`
Bracket,
/// `∅ ... ∅`
/// An invisible delimiter, that may, for example, appear around tokens coming from a
/// "macro variable" `$var`. It is important to preserve operator priorities in cases like
/// `$var * 3` where `$var` is `1 + 2`.
/// Invisible delimiters might not survive roundtrip of a token stream through a string.
Invisible,
}
// Note that the suffix is *not* considered when deciding the `LitKind` in this
// type. This means that float literals like `1f32` are classified by this type
// as `Int`. Only upon conversion to `ast::LitKind` will such a literal be
// given the `Float` kind.
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum LitKind {
Bool, // AST only, must never appear in a `Token`
Byte,
Char,
Integer, // e.g. `1`, `1u8`, `1f32`
Float, // e.g. `1.`, `1.0`, `1e3f32`
Str,
StrRaw(u8), // raw string delimited by `n` hash symbols
ByteStr,
ByteStrRaw(u8), // raw byte string delimited by `n` hash symbols
CStr,
CStrRaw(u8),
Err(ErrorGuaranteed),
}
/// A literal token.
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct Lit {
pub kind: LitKind,
pub symbol: Symbol,
pub suffix: Option<Symbol>,
}
impl Lit {
pub fn new(kind: LitKind, symbol: Symbol, suffix: Option<Symbol>) -> Lit {
Lit { kind, symbol, suffix }
}
/// Returns `true` if this is semantically a float literal. This includes
/// ones like `1f32` that have an `Integer` kind but a float suffix.
pub fn is_semantic_float(&self) -> bool {
match self.kind {
LitKind::Float => true,
LitKind::Integer => match self.suffix {
Some(sym) => sym == sym::f32 || sym == sym::f64,
None => false,
},
_ => false,
}
}
/// Keep this in sync with `Token::can_begin_literal_maybe_minus` excluding unary negation.
pub fn from_token(token: &Token) -> Option<Lit> {
match token.uninterpolate().kind {
Ident(name, IdentIsRaw::No) if name.is_bool_lit() => Some(Lit::new(Bool, name, None)),
Literal(token_lit) => Some(token_lit),
Interpolated(ref nt)
if let NtExpr(expr) | NtLiteral(expr) = &**nt
&& let ast::ExprKind::Lit(token_lit) = expr.kind =>
{
Some(token_lit)
}
_ => None,
}
}
}
impl fmt::Display for Lit {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let Lit { kind, symbol, suffix } = *self;
match kind {
Byte => write!(f, "b'{symbol}'")?,
Char => write!(f, "'{symbol}'")?,
Str => write!(f, "\"{symbol}\"")?,
StrRaw(n) => write!(
f,
"r{delim}\"{string}\"{delim}",
delim = "#".repeat(n as usize),
string = symbol
)?,
ByteStr => write!(f, "b\"{symbol}\"")?,
ByteStrRaw(n) => write!(
f,
"br{delim}\"{string}\"{delim}",
delim = "#".repeat(n as usize),
string = symbol
)?,
CStr => write!(f, "c\"{symbol}\"")?,
CStrRaw(n) => {
write!(f, "cr{delim}\"{symbol}\"{delim}", delim = "#".repeat(n as usize))?
}
Integer | Float | Bool | Err(_) => write!(f, "{symbol}")?,
}
if let Some(suffix) = suffix {
write!(f, "{suffix}")?;
}
Ok(())
}
}
impl LitKind {
/// An English article for the literal token kind.
pub fn article(self) -> &'static str {
match self {
Integer | Err(_) => "an",
_ => "a",
}
}
pub fn descr(self) -> &'static str {
match self {
Bool => "boolean",
Byte => "byte",
Char => "char",
Integer => "integer",
Float => "float",
Str | StrRaw(..) => "string",
ByteStr | ByteStrRaw(..) => "byte string",
CStr | CStrRaw(..) => "C string",
Err(_) => "error",
}
}
pub(crate) fn may_have_suffix(self) -> bool {
matches!(self, Integer | Float | Err(_))
}
}
pub fn ident_can_begin_expr(name: Symbol, span: Span, is_raw: IdentIsRaw) -> bool {
let ident_token = Token::new(Ident(name, is_raw), span);
!ident_token.is_reserved_ident()
|| ident_token.is_path_segment_keyword()
|| [
kw::Async,
kw::Do,
kw::Box,
kw::Break,
kw::Const,
kw::Continue,
kw::False,
kw::For,
kw::Gen,
kw::If,
kw::Let,
kw::Loop,
kw::Match,
kw::Move,
kw::Return,
kw::True,
kw::Try,
kw::Unsafe,
kw::While,
kw::Yield,
kw::Safe,
kw::Static,
]
.contains(&name)
}
fn ident_can_begin_type(name: Symbol, span: Span, is_raw: IdentIsRaw) -> bool {
let ident_token = Token::new(Ident(name, is_raw), span);
!ident_token.is_reserved_ident()
|| ident_token.is_path_segment_keyword()
|| [kw::Underscore, kw::For, kw::Impl, kw::Fn, kw::Unsafe, kw::Extern, kw::Typeof, kw::Dyn]
.contains(&name)
}
#[derive(PartialEq, Encodable, Decodable, Debug, Copy, Clone, HashStable_Generic)]
pub enum IdentIsRaw {
No,
Yes,
}
impl From<bool> for IdentIsRaw {
fn from(b: bool) -> Self {
if b { Self::Yes } else { Self::No }
}
}
impl From<IdentIsRaw> for bool {
fn from(is_raw: IdentIsRaw) -> bool {
matches!(is_raw, IdentIsRaw::Yes)
}
}
// SAFETY: due to the `Clone` impl below, all fields of all variants other than
// `Interpolated` must impl `Copy`.
#[derive(PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum TokenKind {
/* Expression-operator symbols. */
/// `=`
Eq,
/// `<`
Lt,
/// `<=`
Le,
/// `==`
EqEq,
/// `!=`
Ne,
/// `>=`
Ge,
/// `>`
Gt,
/// `&&`
AndAnd,
/// `||`
OrOr,
/// `!`
Not,
/// `~`
Tilde,
BinOp(BinOpToken),
BinOpEq(BinOpToken),
/* Structural symbols */
/// `@`
At,
/// `.`
Dot,
/// `..`
DotDot,
/// `...`
DotDotDot,
/// `..=`
DotDotEq,
/// `,`
Comma,
/// `;`
Semi,
/// `:`
Colon,
/// `::`
PathSep,
/// `->`
RArrow,
/// `<-`
LArrow,
/// `=>`
FatArrow,
/// `#`
Pound,
/// `$`
Dollar,
/// `?`
Question,
/// Used by proc macros for representing lifetimes, not generated by lexer right now.
SingleQuote,
/// An opening delimiter (e.g., `{`).
OpenDelim(Delimiter),
/// A closing delimiter (e.g., `}`).
CloseDelim(Delimiter),
/* Literals */
Literal(Lit),
/// Identifier token.
/// Do not forget about `NtIdent` when you want to match on identifiers.
/// It's recommended to use `Token::(ident,uninterpolate,uninterpolated_span)` to
/// treat regular and interpolated identifiers in the same way.
Ident(Symbol, IdentIsRaw),
/// This identifier (and its span) is the identifier passed to the
/// declarative macro. The span in the surrounding `Token` is the span of
/// the `ident` metavariable in the macro's RHS.
NtIdent(Ident, IdentIsRaw),
/// Lifetime identifier token.
/// Do not forget about `NtLifetime` when you want to match on lifetime identifiers.
/// It's recommended to use `Token::(lifetime,uninterpolate,uninterpolated_span)` to
/// treat regular and interpolated lifetime identifiers in the same way.
Lifetime(Symbol),
/// This identifier (and its span) is the lifetime passed to the
/// declarative macro. The span in the surrounding `Token` is the span of
/// the `lifetime` metavariable in the macro's RHS.
NtLifetime(Ident),
/// An embedded AST node, as produced by a macro. This only exists for
/// historical reasons. We'd like to get rid of it, for multiple reasons.
/// - It's conceptually very strange. Saying a token can contain an AST
/// node is like saying, in natural language, that a word can contain a
/// sentence.
/// - It requires special handling in a bunch of places in the parser.
/// - It prevents `Token` from implementing `Copy`.
/// It adds complexity and likely slows things down. Please don't add new
/// occurrences of this token kind!
///
/// The span in the surrounding `Token` is that of the metavariable in the
/// macro's RHS. The span within the Nonterminal is that of the fragment
/// passed to the macro at the call site.
Interpolated(Lrc<Nonterminal>),
/// A doc comment token.
/// `Symbol` is the doc comment's data excluding its "quotes" (`///`, `/**`, etc)
/// similarly to symbols in string literal tokens.
DocComment(CommentKind, ast::AttrStyle, Symbol),
/// End Of File
Eof,
}
impl Clone for TokenKind {
fn clone(&self) -> Self {
// `TokenKind` would impl `Copy` if it weren't for `Interpolated`. So
// for all other variants, this implementation of `clone` is just like
// a copy. This is faster than the `derive(Clone)` version which has a
// separate path for every variant.
match self {
Interpolated(nt) => Interpolated(nt.clone()),
_ => unsafe { std::ptr::read(self) },
}
}
}
#[derive(Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub struct Token {
pub kind: TokenKind,
pub span: Span,
}
impl TokenKind {
pub fn lit(kind: LitKind, symbol: Symbol, suffix: Option<Symbol>) -> TokenKind {
Literal(Lit::new(kind, symbol, suffix))
}
/// An approximation to proc-macro-style single-character operators used by rustc parser.
/// If the operator token can be broken into two tokens, the first of which is single-character,
/// then this function performs that operation, otherwise it returns `None`.
pub fn break_two_token_op(&self) -> Option<(TokenKind, TokenKind)> {
Some(match *self {
Le => (Lt, Eq),
EqEq => (Eq, Eq),
Ne => (Not, Eq),
Ge => (Gt, Eq),
AndAnd => (BinOp(And), BinOp(And)),
OrOr => (BinOp(Or), BinOp(Or)),
BinOp(Shl) => (Lt, Lt),
BinOp(Shr) => (Gt, Gt),
BinOpEq(Plus) => (BinOp(Plus), Eq),
BinOpEq(Minus) => (BinOp(Minus), Eq),
BinOpEq(Star) => (BinOp(Star), Eq),
BinOpEq(Slash) => (BinOp(Slash), Eq),
BinOpEq(Percent) => (BinOp(Percent), Eq),
BinOpEq(Caret) => (BinOp(Caret), Eq),
BinOpEq(And) => (BinOp(And), Eq),
BinOpEq(Or) => (BinOp(Or), Eq),
BinOpEq(Shl) => (Lt, Le),
BinOpEq(Shr) => (Gt, Ge),
DotDot => (Dot, Dot),
DotDotDot => (Dot, DotDot),
PathSep => (Colon, Colon),
RArrow => (BinOp(Minus), Gt),
LArrow => (Lt, BinOp(Minus)),
FatArrow => (Eq, Gt),
_ => return None,
})
}
/// Returns tokens that are likely to be typed accidentally instead of the current token.
/// Enables better error recovery when the wrong token is found.
pub fn similar_tokens(&self) -> Option<Vec<TokenKind>> {
match *self {
Comma => Some(vec![Dot, Lt, Semi]),
Semi => Some(vec![Colon, Comma]),
Colon => Some(vec![Semi]),
FatArrow => Some(vec![Eq, RArrow, Ge, Gt]),
_ => None,
}
}
pub fn should_end_const_arg(&self) -> bool {
matches!(self, Gt | Ge | BinOp(Shr) | BinOpEq(Shr))
}
}
impl Token {
pub fn new(kind: TokenKind, span: Span) -> Self {
Token { kind, span }
}
/// Some token that will be thrown away later.
pub fn dummy() -> Self {
Token::new(TokenKind::Question, DUMMY_SP)
}
/// Recovers a `Token` from an `Ident`. This creates a raw identifier if necessary.
pub fn from_ast_ident(ident: Ident) -> Self {
Token::new(Ident(ident.name, ident.is_raw_guess().into()), ident.span)
}
/// For interpolated tokens, returns a span of the fragment to which the interpolated
/// token refers. For all other tokens this is just a regular span.
/// It is particularly important to use this for identifiers and lifetimes
/// for which spans affect name resolution and edition checks.
/// Note that keywords are also identifiers, so they should use this
/// if they keep spans or perform edition checks.
pub fn uninterpolated_span(&self) -> Span {
match self.kind {
NtIdent(ident, _) | NtLifetime(ident) => ident.span,
Interpolated(ref nt) => nt.use_span(),
_ => self.span,
}
}
pub fn is_range_separator(&self) -> bool {
[DotDot, DotDotDot, DotDotEq].contains(&self.kind)
}
pub fn is_punct(&self) -> bool {
match self.kind {
Eq | Lt | Le | EqEq | Ne | Ge | Gt | AndAnd | OrOr | Not | Tilde | BinOp(_)
| BinOpEq(_) | At | Dot | DotDot | DotDotDot | DotDotEq | Comma | Semi | Colon
| PathSep | RArrow | LArrow | FatArrow | Pound | Dollar | Question | SingleQuote => {
true
}
OpenDelim(..) | CloseDelim(..) | Literal(..) | DocComment(..) | Ident(..)
| NtIdent(..) | Lifetime(..) | NtLifetime(..) | Interpolated(..) | Eof => false,
}
}
pub fn is_like_plus(&self) -> bool {
matches!(self.kind, BinOp(Plus) | BinOpEq(Plus))
}
/// Returns `true` if the token can appear at the start of an expression.
pub fn can_begin_expr(&self) -> bool {
match self.uninterpolate().kind {
Ident(name, is_raw) =>
ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
OpenDelim(..) | // tuple, array or block
Literal(..) | // literal
Not | // operator not
BinOp(Minus) | // unary minus
BinOp(Star) | // dereference
BinOp(Or) | OrOr | // closure
BinOp(And) | // reference
AndAnd | // double reference
// DotDotDot is no longer supported, but we need some way to display the error
DotDot | DotDotDot | DotDotEq | // range notation
Lt | BinOp(Shl) | // associated path
PathSep | // global path
Lifetime(..) | // labeled loop
Pound => true, // expression attributes
Interpolated(ref nt) => matches!(&**nt, NtLiteral(..) |
NtExpr(..) |
NtBlock(..) |
NtPath(..)),
_ => false,
}
}
/// Returns `true` if the token can appear at the start of a pattern.
///
/// Shamelessly borrowed from `can_begin_expr`, only used for diagnostics right now.
pub fn can_begin_pattern(&self) -> bool {
match self.uninterpolate().kind {
Ident(name, is_raw) =>
ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
| OpenDelim(Delimiter::Bracket | Delimiter::Parenthesis) // tuple or array
| Literal(..) // literal
| BinOp(Minus) // unary minus
| BinOp(And) // reference
| AndAnd // double reference
// DotDotDot is no longer supported
| DotDot | DotDotDot | DotDotEq // ranges
| Lt | BinOp(Shl) // associated path
| PathSep => true, // global path
Interpolated(ref nt) => matches!(&**nt, NtLiteral(..) |
NtPat(..) |
NtBlock(..) |
NtPath(..)),
_ => false,
}
}
/// Returns `true` if the token can appear at the start of a type.
pub fn can_begin_type(&self) -> bool {
match self.uninterpolate().kind {
Ident(name, is_raw) =>
ident_can_begin_type(name, self.span, is_raw), // type name or keyword
OpenDelim(Delimiter::Parenthesis) | // tuple
OpenDelim(Delimiter::Bracket) | // array
Not | // never
BinOp(Star) | // raw pointer
BinOp(And) | // reference
AndAnd | // double reference
Question | // maybe bound in trait object
Lifetime(..) | // lifetime bound in trait object
Lt | BinOp(Shl) | // associated path
PathSep => true, // global path
Interpolated(ref nt) => matches!(&**nt, NtTy(..) | NtPath(..)),
// For anonymous structs or unions, which only appear in specific positions
// (type of struct fields or union fields), we don't consider them as regular types
_ => false,
}
}
/// Returns `true` if the token can appear at the start of a const param.
pub fn can_begin_const_arg(&self) -> bool {
match self.kind {
OpenDelim(Delimiter::Brace) | Literal(..) | BinOp(Minus) => true,
Ident(name, IdentIsRaw::No) if name.is_bool_lit() => true,
Interpolated(ref nt) => matches!(&**nt, NtExpr(..) | NtBlock(..) | NtLiteral(..)),
_ => false,
}
}
/// Returns `true` if the token can appear at the start of an item.
pub fn can_begin_item(&self) -> bool {
match self.kind {
Ident(name, _) => [
kw::Fn,
kw::Use,
kw::Struct,
kw::Enum,
kw::Pub,
kw::Trait,
kw::Extern,
kw::Impl,
kw::Unsafe,
kw::Const,
kw::Safe,
kw::Static,
kw::Union,
kw::Macro,
kw::Mod,
kw::Type,
]
.contains(&name),
_ => false,
}
}
/// Returns `true` if the token is any literal.
pub fn is_lit(&self) -> bool {
matches!(self.kind, Literal(..))
}
/// Returns `true` if the token is any literal, a minus (which can prefix a literal,
/// for example a '-42', or one of the boolean idents).
///
/// In other words, would this token be a valid start of `parse_literal_maybe_minus`?
///
/// Keep this in sync with and `Lit::from_token`, excluding unary negation.
pub fn can_begin_literal_maybe_minus(&self) -> bool {
match self.uninterpolate().kind {
Literal(..) | BinOp(Minus) => true,
Ident(name, IdentIsRaw::No) if name.is_bool_lit() => true,
Interpolated(ref nt) => match &**nt {
NtLiteral(_) => true,
NtExpr(e) => match &e.kind {
ast::ExprKind::Lit(_) => true,
ast::ExprKind::Unary(ast::UnOp::Neg, e) => {
matches!(&e.kind, ast::ExprKind::Lit(_))
}
_ => false,
},
_ => false,
},
_ => false,
}
}
pub fn can_begin_string_literal(&self) -> bool {
match self.uninterpolate().kind {
Literal(..) => true,
Interpolated(ref nt) => match &**nt {
NtLiteral(_) => true,
NtExpr(e) => match &e.kind {
ast::ExprKind::Lit(_) => true,
_ => false,
},
_ => false,
},
_ => false,
}
}
/// A convenience function for matching on identifiers during parsing.
/// Turns interpolated identifier (`$i: ident`) or lifetime (`$l: lifetime`) token
/// into the regular identifier or lifetime token it refers to,
/// otherwise returns the original token.
pub fn uninterpolate(&self) -> Cow<'_, Token> {
match self.kind {
NtIdent(ident, is_raw) => Cow::Owned(Token::new(Ident(ident.name, is_raw), ident.span)),
NtLifetime(ident) => Cow::Owned(Token::new(Lifetime(ident.name), ident.span)),
_ => Cow::Borrowed(self),
}
}
/// Returns an identifier if this token is an identifier.
#[inline]
pub fn ident(&self) -> Option<(Ident, IdentIsRaw)> {
// We avoid using `Token::uninterpolate` here because it's slow.
match self.kind {
Ident(name, is_raw) => Some((Ident::new(name, self.span), is_raw)),
NtIdent(ident, is_raw) => Some((ident, is_raw)),
_ => None,
}
}
/// Returns a lifetime identifier if this token is a lifetime.
#[inline]
pub fn lifetime(&self) -> Option<Ident> {
// We avoid using `Token::uninterpolate` here because it's slow.
match self.kind {
Lifetime(name) => Some(Ident::new(name, self.span)),
NtLifetime(ident) => Some(ident),
_ => None,
}
}
/// Returns `true` if the token is an identifier.
pub fn is_ident(&self) -> bool {
self.ident().is_some()
}
/// Returns `true` if the token is a lifetime.
pub fn is_lifetime(&self) -> bool {
self.lifetime().is_some()
}
/// Returns `true` if the token is an identifier whose name is the given
/// string slice.
pub fn is_ident_named(&self, name: Symbol) -> bool {
self.ident().is_some_and(|(ident, _)| ident.name == name)
}
/// Returns `true` if the token is an interpolated path.
fn is_whole_path(&self) -> bool {
if let Interpolated(nt) = &self.kind
&& let NtPath(..) = &**nt
{
return true;
}
false
}
/// Is this a pre-parsed expression dropped into the token stream
/// (which happens while parsing the result of macro expansion)?
pub fn is_whole_expr(&self) -> bool {
if let Interpolated(nt) = &self.kind
&& let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtBlock(_) = &**nt
{
return true;
}
false
}
/// Is the token an interpolated block (`$b:block`)?
pub fn is_whole_block(&self) -> bool {
if let Interpolated(nt) = &self.kind
&& let NtBlock(..) = &**nt
{
return true;
}
false
}
/// Returns `true` if the token is either the `mut` or `const` keyword.
pub fn is_mutability(&self) -> bool {
self.is_keyword(kw::Mut) || self.is_keyword(kw::Const)
}
pub fn is_qpath_start(&self) -> bool {
self == &Lt || self == &BinOp(Shl)
}
pub fn is_path_start(&self) -> bool {
self == &PathSep
|| self.is_qpath_start()
|| self.is_whole_path()
|| self.is_path_segment_keyword()
|| self.is_ident() && !self.is_reserved_ident()
}
/// Returns `true` if the token is a given keyword, `kw`.
pub fn is_keyword(&self, kw: Symbol) -> bool {
self.is_non_raw_ident_where(|id| id.name == kw)
}
/// Returns `true` if the token is a given keyword, `kw` or if `case` is `Insensitive` and this token is an identifier equal to `kw` ignoring the case.
pub fn is_keyword_case(&self, kw: Symbol, case: Case) -> bool {
self.is_keyword(kw)
|| (case == Case::Insensitive
&& self.is_non_raw_ident_where(|id| {
id.name.as_str().to_lowercase() == kw.as_str().to_lowercase()
}))
}
pub fn is_path_segment_keyword(&self) -> bool {
self.is_non_raw_ident_where(Ident::is_path_segment_keyword)
}
/// Returns true for reserved identifiers used internally for elided lifetimes,
/// unnamed method parameters, crate root module, error recovery etc.
pub fn is_special_ident(&self) -> bool {
self.is_non_raw_ident_where(Ident::is_special)
}
/// Returns `true` if the token is a keyword used in the language.
pub fn is_used_keyword(&self) -> bool {
self.is_non_raw_ident_where(Ident::is_used_keyword)
}
/// Returns `true` if the token is a keyword reserved for possible future use.
pub fn is_unused_keyword(&self) -> bool {
self.is_non_raw_ident_where(Ident::is_unused_keyword)
}
/// Returns `true` if the token is either a special identifier or a keyword.
pub fn is_reserved_ident(&self) -> bool {
self.is_non_raw_ident_where(Ident::is_reserved)
}
/// Returns `true` if the token is the identifier `true` or `false`.
pub fn is_bool_lit(&self) -> bool {
self.is_non_raw_ident_where(|id| id.name.is_bool_lit())
}
pub fn is_numeric_lit(&self) -> bool {
matches!(
self.kind,
Literal(Lit { kind: LitKind::Integer, .. }) | Literal(Lit { kind: LitKind::Float, .. })
)
}
/// Returns `true` if the token is the integer literal.
pub fn is_integer_lit(&self) -> bool {
matches!(self.kind, Literal(Lit { kind: LitKind::Integer, .. }))
}
/// Returns `true` if the token is a non-raw identifier for which `pred` holds.
pub fn is_non_raw_ident_where(&self, pred: impl FnOnce(Ident) -> bool) -> bool {
match self.ident() {
Some((id, IdentIsRaw::No)) => pred(id),
_ => false,
}
}
pub fn glue(&self, joint: &Token) -> Option<Token> {
let kind = match self.kind {
Eq => match joint.kind {
Eq => EqEq,
Gt => FatArrow,
_ => return None,
},
Lt => match joint.kind {
Eq => Le,
Lt => BinOp(Shl),
Le => BinOpEq(Shl),
BinOp(Minus) => LArrow,
_ => return None,
},
Gt => match joint.kind {
Eq => Ge,
Gt => BinOp(Shr),
Ge => BinOpEq(Shr),
_ => return None,
},
Not => match joint.kind {
Eq => Ne,
_ => return None,
},
BinOp(op) => match joint.kind {
Eq => BinOpEq(op),
BinOp(And) if op == And => AndAnd,
BinOp(Or) if op == Or => OrOr,
Gt if op == Minus => RArrow,
_ => return None,
},
Dot => match joint.kind {
Dot => DotDot,
DotDot => DotDotDot,
_ => return None,
},
DotDot => match joint.kind {
Dot => DotDotDot,
Eq => DotDotEq,
_ => return None,
},
Colon => match joint.kind {
Colon => PathSep,
_ => return None,
},
SingleQuote => match joint.kind {
Ident(name, IdentIsRaw::No) => Lifetime(Symbol::intern(&format!("'{name}"))),
_ => return None,
},
Le | EqEq | Ne | Ge | AndAnd | OrOr | Tilde | BinOpEq(..) | At | DotDotDot
| DotDotEq | Comma | Semi | PathSep | RArrow | LArrow | FatArrow | Pound | Dollar
| Question | OpenDelim(..) | CloseDelim(..) | Literal(..) | Ident(..) | NtIdent(..)
| Lifetime(..) | NtLifetime(..) | Interpolated(..) | DocComment(..) | Eof => {
return None;
}
};
Some(Token::new(kind, self.span.to(joint.span)))
}
}
impl PartialEq<TokenKind> for Token {
#[inline]
fn eq(&self, rhs: &TokenKind) -> bool {
self.kind == *rhs
}
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, Encodable, Decodable)]
pub enum NtPatKind {
// Matches or-patterns. Was written using `pat` in edition 2021 or later.
PatWithOr,
// Doesn't match or-patterns.
// - `inferred`: was written using `pat` in edition 2015 or 2018.
// - `!inferred`: was written using `pat_param`.
PatParam { inferred: bool },
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, Encodable, Decodable)]
pub enum NtExprKind {
// Matches expressions using the post-edition 2024. Was written using
// `expr` in edition 2024 or later.
Expr,
// Matches expressions using the pre-edition 2024 rules.
// - `inferred`: was written using `expr` in edition 2021 or earlier.
// - `!inferred`: was written using `expr_2021`.
Expr2021 { inferred: bool },
}
#[derive(Clone, Encodable, Decodable)]
/// For interpolation during macro expansion.
pub enum Nonterminal {
NtItem(P<ast::Item>),
NtBlock(P<ast::Block>),
NtStmt(P<ast::Stmt>),
NtPat(P<ast::Pat>),
NtExpr(P<ast::Expr>),
NtTy(P<ast::Ty>),
NtLiteral(P<ast::Expr>),
/// Stuff inside brackets for attributes
NtMeta(P<ast::AttrItem>),
NtPath(P<ast::Path>),
NtVis(P<ast::Visibility>),
}
#[derive(Debug, Copy, Clone, PartialEq, Encodable, Decodable)]
pub enum NonterminalKind {
Item,
Block,
Stmt,
Pat(NtPatKind),
Expr(NtExprKind),
Ty,
Ident,
Lifetime,
Literal,
Meta,
Path,
Vis,
TT,
}
impl NonterminalKind {
/// The `edition` closure is used to get the edition for the given symbol. Doing
/// `span.edition()` is expensive, so we do it lazily.
pub fn from_symbol(
symbol: Symbol,
edition: impl FnOnce() -> Edition,
) -> Option<NonterminalKind> {
Some(match symbol {
sym::item => NonterminalKind::Item,
sym::block => NonterminalKind::Block,
sym::stmt => NonterminalKind::Stmt,
sym::pat => {
if edition().at_least_rust_2021() {
NonterminalKind::Pat(PatWithOr)
} else {
NonterminalKind::Pat(PatParam { inferred: true })
}
}
sym::pat_param => NonterminalKind::Pat(PatParam { inferred: false }),
sym::expr => {
if edition().at_least_rust_2024() {
NonterminalKind::Expr(Expr)
} else {
NonterminalKind::Expr(Expr2021 { inferred: true })
}
}
sym::expr_2021 => NonterminalKind::Expr(Expr2021 { inferred: false }),
sym::ty => NonterminalKind::Ty,
sym::ident => NonterminalKind::Ident,
sym::lifetime => NonterminalKind::Lifetime,
sym::literal => NonterminalKind::Literal,
sym::meta => NonterminalKind::Meta,
sym::path => NonterminalKind::Path,
sym::vis => NonterminalKind::Vis,
sym::tt => NonterminalKind::TT,
_ => return None,
})
}
fn symbol(self) -> Symbol {
match self {
NonterminalKind::Item => sym::item,
NonterminalKind::Block => sym::block,
NonterminalKind::Stmt => sym::stmt,
NonterminalKind::Pat(PatParam { inferred: true } | PatWithOr) => sym::pat,
NonterminalKind::Pat(PatParam { inferred: false }) => sym::pat_param,
NonterminalKind::Expr(Expr2021 { inferred: true } | Expr) => sym::expr,
NonterminalKind::Expr(Expr2021 { inferred: false }) => sym::expr_2021,
NonterminalKind::Ty => sym::ty,
NonterminalKind::Ident => sym::ident,
NonterminalKind::Lifetime => sym::lifetime,
NonterminalKind::Literal => sym::literal,
NonterminalKind::Meta => sym::meta,
NonterminalKind::Path => sym::path,
NonterminalKind::Vis => sym::vis,
NonterminalKind::TT => sym::tt,
}
}
}
impl fmt::Display for NonterminalKind {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.symbol())
}
}
impl Nonterminal {
pub fn use_span(&self) -> Span {
match self {
NtItem(item) => item.span,
NtBlock(block) => block.span,
NtStmt(stmt) => stmt.span,
NtPat(pat) => pat.span,
NtExpr(expr) | NtLiteral(expr) => expr.span,
NtTy(ty) => ty.span,
NtMeta(attr_item) => attr_item.span(),
NtPath(path) => path.span,
NtVis(vis) => vis.span,
}
}
pub fn descr(&self) -> &'static str {
match self {
NtItem(..) => "item",
NtBlock(..) => "block",
NtStmt(..) => "statement",
NtPat(..) => "pattern",
NtExpr(..) => "expression",
NtLiteral(..) => "literal",
NtTy(..) => "type",
NtMeta(..) => "attribute",
NtPath(..) => "path",
NtVis(..) => "visibility",
}
}
}
impl PartialEq for Nonterminal {
fn eq(&self, _rhs: &Self) -> bool {
// FIXME: Assume that all nonterminals are not equal, we can't compare them
// correctly based on data from AST. This will prevent them from matching each other
// in macros. The comparison will become possible only when each nonterminal has an
// attached token stream from which it was parsed.
false
}
}
impl fmt::Debug for Nonterminal {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
NtItem(..) => f.pad("NtItem(..)"),
NtBlock(..) => f.pad("NtBlock(..)"),
NtStmt(..) => f.pad("NtStmt(..)"),
NtPat(..) => f.pad("NtPat(..)"),
NtExpr(..) => f.pad("NtExpr(..)"),
NtTy(..) => f.pad("NtTy(..)"),
NtLiteral(..) => f.pad("NtLiteral(..)"),
NtMeta(..) => f.pad("NtMeta(..)"),
NtPath(..) => f.pad("NtPath(..)"),
NtVis(..) => f.pad("NtVis(..)"),
}
}
}
impl<CTX> HashStable<CTX> for Nonterminal
where
CTX: crate::HashStableContext,
{
fn hash_stable(&self, _hcx: &mut CTX, _hasher: &mut StableHasher) {
panic!("interpolated tokens should not be present in the HIR")
}
}
// Some types 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!(Lit, 12);
static_assert_size!(LitKind, 2);
static_assert_size!(Nonterminal, 16);
static_assert_size!(Token, 24);
static_assert_size!(TokenKind, 16);
// tidy-alphabetical-end
}