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Auto merge of #102302 - nnethercote:more-lexer-improvements, r=matklad 

More lexer improvements

A follow-up to #99884.

r? `@matklad`
This commit is contained in:
bors 2022-09-28 08:14:04 +00:00
parent 837bf370de d0a26acb2a
commit 6201eabde8
7 changed files with 443 additions and 457 deletions
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7
compiler/rustc_ast/src/token.rs
View File

@ -13,7 +13,7 @@ use rustc_span::symbol::{kw, sym};
use rustc_span::symbol::{Ident, Symbol};
use rustc_span::{self, edition::Edition, Span, DUMMY_SP};
use std::borrow::Cow;
use std::{fmt, mem};
use std::fmt;
#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
pub enum CommentKind {
@ -335,11 +335,6 @@ impl Token {
Token::new(Ident(ident.name, ident.is_raw_guess()), ident.span)
}
/// Return this token by value and leave a dummy token in its place.
pub fn take(&mut self) -> Self {
mem::replace(self, Token::dummy())
}
/// 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

3
compiler/rustc_errors/src/lib.rs
View File

@ -62,7 +62,8 @@ pub mod translation;
pub use diagnostic_builder::IntoDiagnostic;
pub use snippet::Style;
pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a, ErrorGuaranteed>>;
pub type PErr<'a> = DiagnosticBuilder<'a, ErrorGuaranteed>;
pub type PResult<'a, T> = Result<T, PErr<'a>>;
// `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
// (See also the comment on `DiagnosticBuilder`'s `diagnostic` field.)

16
compiler/rustc_lexer/src/cursor.rs
View File

@ -4,8 +4,8 @@ use std::str::Chars;
///
/// Next characters can be peeked via `first` method,
/// and position can be shifted forward via `bump` method.
pub(crate) struct Cursor<'a> {
initial_len: usize,
pub struct Cursor<'a> {
len_remaining: usize,
/// Iterator over chars. Slightly faster than a &str.
chars: Chars<'a>,
#[cfg(debug_assertions)]
@ -15,9 +15,9 @@ pub(crate) struct Cursor<'a> {
pub(crate) const EOF_CHAR: char = '\0';
impl<'a> Cursor<'a> {
pub(crate) fn new(input: &'a str) -> Cursor<'a> {
pub fn new(input: &'a str) -> Cursor<'a> {
Cursor {
initial_len: input.len(),
len_remaining: input.len(),
chars: input.chars(),
#[cfg(debug_assertions)]
prev: EOF_CHAR,
@ -61,13 +61,13 @@ impl<'a> Cursor<'a> {
}
/// Returns amount of already consumed symbols.
pub(crate) fn len_consumed(&self) -> u32 {
(self.initial_len - self.chars.as_str().len()) as u32
pub(crate) fn pos_within_token(&self) -> u32 {
(self.len_remaining - self.chars.as_str().len()) as u32
}
/// Resets the number of bytes consumed to 0.
pub(crate) fn reset_len_consumed(&mut self) {
self.initial_len = self.chars.as_str().len();
pub(crate) fn reset_pos_within_token(&mut self) {
self.len_remaining = self.chars.as_str().len();
}
/// Moves to the next character.

53
compiler/rustc_lexer/src/lib.rs
View File

@ -29,9 +29,11 @@ pub mod unescape;
#[cfg(test)]
mod tests;
pub use crate::cursor::Cursor;
use self::LiteralKind::*;
use self::TokenKind::*;
use crate::cursor::{Cursor, EOF_CHAR};
use crate::cursor::EOF_CHAR;
use std::convert::TryFrom;
/// Parsed token.
@ -139,6 +141,9 @@ pub enum TokenKind {
/// Unknown token, not expected by the lexer, e.g. "№"
Unknown,
/// End of input.
Eof,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
@ -219,13 +224,6 @@ pub fn strip_shebang(input: &str) -> Option<usize> {
None
}
/// Parses the first token from the provided input string.
#[inline]
pub fn first_token(input: &str) -> Token {
debug_assert!(!input.is_empty());
Cursor::new(input).advance_token()
}
/// Validates a raw string literal. Used for getting more information about a
/// problem with a `RawStr`/`RawByteStr` with a `None` field.
#[inline]
@ -243,12 +241,8 @@ pub fn validate_raw_str(input: &str, prefix_len: u32) -> Result<(), RawStrError>
pub fn tokenize(input: &str) -> impl Iterator<Item = Token> + '_ {
let mut cursor = Cursor::new(input);
std::iter::from_fn(move || {
if cursor.is_eof() {
None
} else {
cursor.reset_len_consumed();
Some(cursor.advance_token())
}
let token = cursor.advance_token();
if token.kind != TokenKind::Eof { Some(token) } else { None }
})
}
@ -311,8 +305,11 @@ pub fn is_ident(string: &str) -> bool {
impl Cursor<'_> {
/// Parses a token from the input string.
fn advance_token(&mut self) -> Token {
let first_char = self.bump().unwrap();
pub fn advance_token(&mut self) -> Token {
let first_char = match self.bump() {
Some(c) => c,
None => return Token::new(TokenKind::Eof, 0),
};
let token_kind = match first_char {
// Slash, comment or block comment.
'/' => match self.first() {
@ -329,7 +326,7 @@ impl Cursor<'_> {
('#', c1) if is_id_start(c1) => self.raw_ident(),
('#', _) | ('"', _) => {
let res = self.raw_double_quoted_string(1);
let suffix_start = self.len_consumed();
let suffix_start = self.pos_within_token();
if res.is_ok() {
self.eat_literal_suffix();
}
@ -344,7 +341,7 @@ impl Cursor<'_> {
('\'', _) => {
self.bump();
let terminated = self.single_quoted_string();
let suffix_start = self.len_consumed();
let suffix_start = self.pos_within_token();
if terminated {
self.eat_literal_suffix();
}
@ -354,7 +351,7 @@ impl Cursor<'_> {
('"', _) => {
self.bump();
let terminated = self.double_quoted_string();
let suffix_start = self.len_consumed();
let suffix_start = self.pos_within_token();
if terminated {
self.eat_literal_suffix();
}
@ -364,7 +361,7 @@ impl Cursor<'_> {
('r', '"') | ('r', '#') => {
self.bump();
let res = self.raw_double_quoted_string(2);
let suffix_start = self.len_consumed();
let suffix_start = self.pos_within_token();
if res.is_ok() {
self.eat_literal_suffix();
}
@ -381,7 +378,7 @@ impl Cursor<'_> {
// Numeric literal.
c @ '0'..='9' => {
let literal_kind = self.number(c);
let suffix_start = self.len_consumed();
let suffix_start = self.pos_within_token();
self.eat_literal_suffix();
TokenKind::Literal { kind: literal_kind, suffix_start }
}
@ -420,7 +417,7 @@ impl Cursor<'_> {
// String literal.
'"' => {
let terminated = self.double_quoted_string();
let suffix_start = self.len_consumed();
let suffix_start = self.pos_within_token();
if terminated {
self.eat_literal_suffix();
}
@ -433,7 +430,9 @@ impl Cursor<'_> {
}
_ => Unknown,
};
Token::new(token_kind, self.len_consumed())
let res = Token::new(token_kind, self.pos_within_token());
self.reset_pos_within_token();
res
}
fn line_comment(&mut self) -> TokenKind {
@ -618,7 +617,7 @@ impl Cursor<'_> {
if !can_be_a_lifetime {
let terminated = self.single_quoted_string();
let suffix_start = self.len_consumed();
let suffix_start = self.pos_within_token();
if terminated {
self.eat_literal_suffix();
}
@ -643,7 +642,7 @@ impl Cursor<'_> {
if self.first() == '\'' {
self.bump();
let kind = Char { terminated: true };
Literal { kind, suffix_start: self.len_consumed() }
Literal { kind, suffix_start: self.pos_within_token() }
} else {
Lifetime { starts_with_number }
}
@ -724,7 +723,7 @@ impl Cursor<'_> {
fn raw_string_unvalidated(&mut self, prefix_len: u32) -> Result<u32, RawStrError> {
debug_assert!(self.prev() == 'r');
let start_pos = self.len_consumed();
let start_pos = self.pos_within_token();
let mut possible_terminator_offset = None;
let mut max_hashes = 0;
@ -778,7 +777,7 @@ impl Cursor<'_> {
// Keep track of possible terminators to give a hint about
// where there might be a missing terminator
possible_terminator_offset =
Some(self.len_consumed() - start_pos - n_end_hashes + prefix_len);
Some(self.pos_within_token() - start_pos - n_end_hashes + prefix_len);
max_hashes = n_end_hashes;
}
}

392
compiler/rustc_parse/src/lexer/mod.rs
View File

@ -1,10 +1,11 @@
use crate::lexer::unicode_chars::UNICODE_ARRAY;
use rustc_ast::ast::{self, AttrStyle};
use rustc_ast::token::{self, CommentKind, Delimiter, Token, TokenKind};
use rustc_ast::tokenstream::{Spacing, TokenStream};
use rustc_ast::tokenstream::TokenStream;
use rustc_ast::util::unicode::contains_text_flow_control_chars;
use rustc_errors::{error_code, Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
use rustc_lexer::unescape::{self, Mode};
use rustc_lexer::Cursor;
use rustc_lexer::{Base, DocStyle, RawStrError};
use rustc_session::lint::builtin::{
RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX, TEXT_DIRECTION_CODEPOINT_IN_COMMENT,
@ -38,11 +39,20 @@ pub struct UnmatchedBrace {
pub(crate) fn parse_token_trees<'a>(
sess: &'a ParseSess,
src: &'a str,
start_pos: BytePos,
mut src: &'a str,
mut start_pos: BytePos,
override_span: Option<Span>,
) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) {
StringReader { sess, start_pos, pos: start_pos, src, override_span }.into_token_trees()
// Skip `#!`, if present.
if let Some(shebang_len) = rustc_lexer::strip_shebang(src) {
src = &src[shebang_len..];
start_pos = start_pos + BytePos::from_usize(shebang_len);
}
let cursor = Cursor::new(src);
let string_reader =
StringReader { sess, start_pos, pos: start_pos, src, cursor, override_span };
tokentrees::TokenTreesReader::parse_token_trees(string_reader)
}
struct StringReader<'a> {
@ -53,6 +63,8 @@ struct StringReader<'a> {
pos: BytePos,
/// Source text to tokenize.
src: &'a str,
/// Cursor for getting lexer tokens.
cursor: Cursor<'a>,
override_span: Option<Span>,
}
@ -61,42 +73,195 @@ impl<'a> StringReader<'a> {
self.override_span.unwrap_or_else(|| Span::with_root_ctxt(lo, hi))
}
/// Returns the next token, and info about preceding whitespace, if any.
fn next_token(&mut self) -> (Spacing, Token) {
let mut spacing = Spacing::Joint;
// Skip `#!` at the start of the file
if self.pos == self.start_pos
&& let Some(shebang_len) = rustc_lexer::strip_shebang(self.src)
{
self.pos = self.pos + BytePos::from_usize(shebang_len);
spacing = Spacing::Alone;
}
/// Returns the next token, paired with a bool indicating if the token was
/// preceded by whitespace.
fn next_token(&mut self) -> (Token, bool) {
let mut preceded_by_whitespace = false;
// Skip trivial (whitespace & comments) tokens
loop {
let start_src_index = self.src_index(self.pos);
let text: &str = &self.src[start_src_index..];
if text.is_empty() {
let span = self.mk_sp(self.pos, self.pos);
return (spacing, Token::new(token::Eof, span));
}
let token = rustc_lexer::first_token(text);
let token = self.cursor.advance_token();
let start = self.pos;
self.pos = self.pos + BytePos(token.len);
debug!("next_token: {:?}({:?})", token.kind, self.str_from(start));
match self.cook_lexer_token(token.kind, start) {
Some(kind) => {
let span = self.mk_sp(start, self.pos);
return (spacing, Token::new(kind, span));
// Now "cook" the token, converting the simple `rustc_lexer::TokenKind` enum into a
// rich `rustc_ast::TokenKind`. This turns strings into interned symbols and runs
// additional validation.
let kind = match token.kind {
rustc_lexer::TokenKind::LineComment { doc_style } => {
// Skip non-doc comments
let Some(doc_style) = doc_style else {
self.lint_unicode_text_flow(start);
preceded_by_whitespace = true;
continue;
};
// Opening delimiter of the length 3 is not included into the symbol.
let content_start = start + BytePos(3);
let content = self.str_from(content_start);
self.cook_doc_comment(content_start, content, CommentKind::Line, doc_style)
}
None => spacing = Spacing::Alone,
}
rustc_lexer::TokenKind::BlockComment { doc_style, terminated } => {
if !terminated {
self.report_unterminated_block_comment(start, doc_style);
}
// Skip non-doc comments
let Some(doc_style) = doc_style else {
self.lint_unicode_text_flow(start);
preceded_by_whitespace = true;
continue;
};
// Opening delimiter of the length 3 and closing delimiter of the length 2
// are not included into the symbol.
let content_start = start + BytePos(3);
let content_end = self.pos - BytePos(if terminated { 2 } else { 0 });
let content = self.str_from_to(content_start, content_end);
self.cook_doc_comment(content_start, content, CommentKind::Block, doc_style)
}
rustc_lexer::TokenKind::Whitespace => {
preceded_by_whitespace = true;
continue;
}
rustc_lexer::TokenKind::Ident => {
let sym = nfc_normalize(self.str_from(start));
let span = self.mk_sp(start, self.pos);
self.sess.symbol_gallery.insert(sym, span);
token::Ident(sym, false)
}
rustc_lexer::TokenKind::RawIdent => {
let sym = nfc_normalize(self.str_from(start + BytePos(2)));
let span = self.mk_sp(start, self.pos);
self.sess.symbol_gallery.insert(sym, span);
if !sym.can_be_raw() {
self.err_span(span, &format!("`{}` cannot be a raw identifier", sym));
}
self.sess.raw_identifier_spans.borrow_mut().push(span);
token::Ident(sym, true)
}
rustc_lexer::TokenKind::UnknownPrefix => {
self.report_unknown_prefix(start);
let sym = nfc_normalize(self.str_from(start));
let span = self.mk_sp(start, self.pos);
self.sess.symbol_gallery.insert(sym, span);
token::Ident(sym, false)
}
rustc_lexer::TokenKind::InvalidIdent
// Do not recover an identifier with emoji if the codepoint is a confusable
// with a recoverable substitution token, like `➖`.
if !UNICODE_ARRAY
.iter()
.any(|&(c, _, _)| {
let sym = self.str_from(start);
sym.chars().count() == 1 && c == sym.chars().next().unwrap()
}) =>
{
let sym = nfc_normalize(self.str_from(start));
let span = self.mk_sp(start, self.pos);
self.sess.bad_unicode_identifiers.borrow_mut().entry(sym).or_default()
.push(span);
token::Ident(sym, false)
}
rustc_lexer::TokenKind::Literal { kind, suffix_start } => {
let suffix_start = start + BytePos(suffix_start);
let (kind, symbol) = self.cook_lexer_literal(start, suffix_start, kind);
let suffix = if suffix_start < self.pos {
let string = self.str_from(suffix_start);
if string == "_" {
self.sess
.span_diagnostic
.struct_span_warn(
self.mk_sp(suffix_start, self.pos),
"underscore literal suffix is not allowed",
)
.warn(
"this was previously accepted by the compiler but is \
being phased out; it will become a hard error in \
a future release!",
)
.note(
"see issue #42326 \
<https://github.com/rust-lang/rust/issues/42326> \
for more information",
)
.emit();
None
} else {
Some(Symbol::intern(string))
}
} else {
None
};
token::Literal(token::Lit { kind, symbol, suffix })
}
rustc_lexer::TokenKind::Lifetime { starts_with_number } => {
// Include the leading `'` in the real identifier, for macro
// expansion purposes. See #12512 for the gory details of why
// this is necessary.
let lifetime_name = self.str_from(start);
if starts_with_number {
self.err_span_(start, self.pos, "lifetimes cannot start with a number");
}
let ident = Symbol::intern(lifetime_name);
token::Lifetime(ident)
}
rustc_lexer::TokenKind::Semi => token::Semi,
rustc_lexer::TokenKind::Comma => token::Comma,
rustc_lexer::TokenKind::Dot => token::Dot,
rustc_lexer::TokenKind::OpenParen => token::OpenDelim(Delimiter::Parenthesis),
rustc_lexer::TokenKind::CloseParen => token::CloseDelim(Delimiter::Parenthesis),
rustc_lexer::TokenKind::OpenBrace => token::OpenDelim(Delimiter::Brace),
rustc_lexer::TokenKind::CloseBrace => token::CloseDelim(Delimiter::Brace),
rustc_lexer::TokenKind::OpenBracket => token::OpenDelim(Delimiter::Bracket),
rustc_lexer::TokenKind::CloseBracket => token::CloseDelim(Delimiter::Bracket),
rustc_lexer::TokenKind::At => token::At,
rustc_lexer::TokenKind::Pound => token::Pound,
rustc_lexer::TokenKind::Tilde => token::Tilde,
rustc_lexer::TokenKind::Question => token::Question,
rustc_lexer::TokenKind::Colon => token::Colon,
rustc_lexer::TokenKind::Dollar => token::Dollar,
rustc_lexer::TokenKind::Eq => token::Eq,
rustc_lexer::TokenKind::Bang => token::Not,
rustc_lexer::TokenKind::Lt => token::Lt,
rustc_lexer::TokenKind::Gt => token::Gt,
rustc_lexer::TokenKind::Minus => token::BinOp(token::Minus),
rustc_lexer::TokenKind::And => token::BinOp(token::And),
rustc_lexer::TokenKind::Or => token::BinOp(token::Or),
rustc_lexer::TokenKind::Plus => token::BinOp(token::Plus),
rustc_lexer::TokenKind::Star => token::BinOp(token::Star),
rustc_lexer::TokenKind::Slash => token::BinOp(token::Slash),
rustc_lexer::TokenKind::Caret => token::BinOp(token::Caret),
rustc_lexer::TokenKind::Percent => token::BinOp(token::Percent),
rustc_lexer::TokenKind::Unknown | rustc_lexer::TokenKind::InvalidIdent => {
let c = self.str_from(start).chars().next().unwrap();
let mut err =
self.struct_err_span_char(start, self.pos, "unknown start of token", c);
// FIXME: the lexer could be used to turn the ASCII version of unicode
// homoglyphs, instead of keeping a table in `check_for_substitution`into the
// token. Ideally, this should be inside `rustc_lexer`. However, we should
// first remove compound tokens like `<<` from `rustc_lexer`, and then add
// fancier error recovery to it, as there will be less overall work to do this
// way.
let token = unicode_chars::check_for_substitution(self, start, c, &mut err);
if c == '\x00' {
err.help("source files must contain UTF-8 encoded text, unexpected null bytes might occur when a different encoding is used");
}
err.emit();
if let Some(token) = token {
token
} else {
preceded_by_whitespace = true;
continue;
}
}
rustc_lexer::TokenKind::Eof => token::Eof,
};
let span = self.mk_sp(start, self.pos);
return (Token::new(kind, span), preceded_by_whitespace);
}
}
@ -162,171 +327,6 @@ impl<'a> StringReader<'a> {
}
}
/// Turns simple `rustc_lexer::TokenKind` enum into a rich
/// `rustc_ast::TokenKind`. This turns strings into interned
/// symbols and runs additional validation.
fn cook_lexer_token(&self, token: rustc_lexer::TokenKind, start: BytePos) -> Option<TokenKind> {
Some(match token {
rustc_lexer::TokenKind::LineComment { doc_style } => {
// Skip non-doc comments
let Some(doc_style) = doc_style else {
self.lint_unicode_text_flow(start);
return None;
};
// Opening delimiter of the length 3 is not included into the symbol.
let content_start = start + BytePos(3);
let content = self.str_from(content_start);
self.cook_doc_comment(content_start, content, CommentKind::Line, doc_style)
}
rustc_lexer::TokenKind::BlockComment { doc_style, terminated } => {
if !terminated {
self.report_unterminated_block_comment(start, doc_style);
}
// Skip non-doc comments
let Some(doc_style) = doc_style else {
self.lint_unicode_text_flow(start);
return None;
};
// Opening delimiter of the length 3 and closing delimiter of the length 2
// are not included into the symbol.
let content_start = start + BytePos(3);
let content_end = self.pos - BytePos(if terminated { 2 } else { 0 });
let content = self.str_from_to(content_start, content_end);
self.cook_doc_comment(content_start, content, CommentKind::Block, doc_style)
}
rustc_lexer::TokenKind::Whitespace => return None,
rustc_lexer::TokenKind::Ident
| rustc_lexer::TokenKind::RawIdent
| rustc_lexer::TokenKind::UnknownPrefix => {
let is_raw_ident = token == rustc_lexer::TokenKind::RawIdent;
let is_unknown_prefix = token == rustc_lexer::TokenKind::UnknownPrefix;
let mut ident_start = start;
if is_raw_ident {
ident_start = ident_start + BytePos(2);
}
if is_unknown_prefix {
self.report_unknown_prefix(start);
}
let sym = nfc_normalize(self.str_from(ident_start));
let span = self.mk_sp(start, self.pos);
self.sess.symbol_gallery.insert(sym, span);
if is_raw_ident {
if !sym.can_be_raw() {
self.err_span(span, &format!("`{}` cannot be a raw identifier", sym));
}
self.sess.raw_identifier_spans.borrow_mut().push(span);
}
token::Ident(sym, is_raw_ident)
}
rustc_lexer::TokenKind::InvalidIdent
// Do not recover an identifier with emoji if the codepoint is a confusable
// with a recoverable substitution token, like `➖`.
if !UNICODE_ARRAY
.iter()
.any(|&(c, _, _)| {
let sym = self.str_from(start);
sym.chars().count() == 1 && c == sym.chars().next().unwrap()
})
=>
{
let sym = nfc_normalize(self.str_from(start));
let span = self.mk_sp(start, self.pos);
self.sess.bad_unicode_identifiers.borrow_mut().entry(sym).or_default().push(span);
token::Ident(sym, false)
}
rustc_lexer::TokenKind::Literal { kind, suffix_start } => {
let suffix_start = start + BytePos(suffix_start);
let (kind, symbol) = self.cook_lexer_literal(start, suffix_start, kind);
let suffix = if suffix_start < self.pos {
let string = self.str_from(suffix_start);
if string == "_" {
self.sess
.span_diagnostic
.struct_span_warn(
self.mk_sp(suffix_start, self.pos),
"underscore literal suffix is not allowed",
)
.warn(
"this was previously accepted by the compiler but is \
being phased out; it will become a hard error in \
a future release!",
)
.note(
"see issue #42326 \
<https://github.com/rust-lang/rust/issues/42326> \
for more information",
)
.emit();
None
} else {
Some(Symbol::intern(string))
}
} else {
None
};
token::Literal(token::Lit { kind, symbol, suffix })
}
rustc_lexer::TokenKind::Lifetime { starts_with_number } => {
// Include the leading `'` in the real identifier, for macro
// expansion purposes. See #12512 for the gory details of why
// this is necessary.
let lifetime_name = self.str_from(start);
if starts_with_number {
self.err_span_(start, self.pos, "lifetimes cannot start with a number");
}
let ident = Symbol::intern(lifetime_name);
token::Lifetime(ident)
}
rustc_lexer::TokenKind::Semi => token::Semi,
rustc_lexer::TokenKind::Comma => token::Comma,
rustc_lexer::TokenKind::Dot => token::Dot,
rustc_lexer::TokenKind::OpenParen => token::OpenDelim(Delimiter::Parenthesis),
rustc_lexer::TokenKind::CloseParen => token::CloseDelim(Delimiter::Parenthesis),
rustc_lexer::TokenKind::OpenBrace => token::OpenDelim(Delimiter::Brace),
rustc_lexer::TokenKind::CloseBrace => token::CloseDelim(Delimiter::Brace),
rustc_lexer::TokenKind::OpenBracket => token::OpenDelim(Delimiter::Bracket),
rustc_lexer::TokenKind::CloseBracket => token::CloseDelim(Delimiter::Bracket),
rustc_lexer::TokenKind::At => token::At,
rustc_lexer::TokenKind::Pound => token::Pound,
rustc_lexer::TokenKind::Tilde => token::Tilde,
rustc_lexer::TokenKind::Question => token::Question,
rustc_lexer::TokenKind::Colon => token::Colon,
rustc_lexer::TokenKind::Dollar => token::Dollar,
rustc_lexer::TokenKind::Eq => token::Eq,
rustc_lexer::TokenKind::Bang => token::Not,
rustc_lexer::TokenKind::Lt => token::Lt,
rustc_lexer::TokenKind::Gt => token::Gt,
rustc_lexer::TokenKind::Minus => token::BinOp(token::Minus),
rustc_lexer::TokenKind::And => token::BinOp(token::And),
rustc_lexer::TokenKind::Or => token::BinOp(token::Or),
rustc_lexer::TokenKind::Plus => token::BinOp(token::Plus),
rustc_lexer::TokenKind::Star => token::BinOp(token::Star),
rustc_lexer::TokenKind::Slash => token::BinOp(token::Slash),
rustc_lexer::TokenKind::Caret => token::BinOp(token::Caret),
rustc_lexer::TokenKind::Percent => token::BinOp(token::Percent),
rustc_lexer::TokenKind::Unknown | rustc_lexer::TokenKind::InvalidIdent => {
let c = self.str_from(start).chars().next().unwrap();
let mut err =
self.struct_err_span_char(start, self.pos, "unknown start of token", c);
// FIXME: the lexer could be used to turn the ASCII version of unicode homoglyphs,
// instead of keeping a table in `check_for_substitution`into the token. Ideally,
// this should be inside `rustc_lexer`. However, we should first remove compound
// tokens like `<<` from `rustc_lexer`, and then add fancier error recovery to it,
// as there will be less overall work to do this way.
let token = unicode_chars::check_for_substitution(self, start, c, &mut err);
if c == '\x00' {
err.help("source files must contain UTF-8 encoded text, unexpected null bytes might occur when a different encoding is used");
}
err.emit();
token?
}
})
}
fn cook_doc_comment(
&self,
content_start: BytePos,

420
compiler/rustc_parse/src/lexer/tokentrees.rs
View File

@ -1,31 +1,15 @@
use super::{StringReader, UnmatchedBrace};
use rustc_ast::token::{self, Delimiter, Token};
use rustc_ast::tokenstream::{DelimSpan, Spacing, TokenStream, TokenTree};
use rustc_ast_pretty::pprust::token_to_string;
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::PResult;
use rustc_errors::{PErr, PResult};
use rustc_span::Span;
impl<'a> StringReader<'a> {
pub(super) fn into_token_trees(self) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) {
let mut tt_reader = TokenTreesReader {
string_reader: self,
token: Token::dummy(),
open_braces: Vec::new(),
unmatched_braces: Vec::new(),
matching_delim_spans: Vec::new(),
last_unclosed_found_span: None,
last_delim_empty_block_spans: FxHashMap::default(),
matching_block_spans: Vec::new(),
};
let res = tt_reader.parse_all_token_trees();
(res, tt_reader.unmatched_braces)
}
}
struct TokenTreesReader<'a> {
pub(super) struct TokenTreesReader<'a> {
string_reader: StringReader<'a>,
/// The "next" token, which has been obtained from the `StringReader` but
/// not yet handled by the `TokenTreesReader`.
token: Token,
/// Stack of open delimiters and their spans. Used for error message.
open_braces: Vec<(Delimiter, Span)>,
@ -43,231 +27,235 @@ struct TokenTreesReader<'a> {
}
impl<'a> TokenTreesReader<'a> {
pub(super) fn parse_token_trees(
string_reader: StringReader<'a>,
) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) {
let mut tt_reader = TokenTreesReader {
string_reader,
token: Token::dummy(),
open_braces: Vec::new(),
unmatched_braces: Vec::new(),
matching_delim_spans: Vec::new(),
last_unclosed_found_span: None,
last_delim_empty_block_spans: FxHashMap::default(),
matching_block_spans: Vec::new(),
};
let res = tt_reader.parse_all_token_trees();
(res, tt_reader.unmatched_braces)
}
// Parse a stream of tokens into a list of `TokenTree`s, up to an `Eof`.
fn parse_all_token_trees(&mut self) -> PResult<'a, TokenStream> {
self.token = self.string_reader.next_token().0;
let mut buf = TokenStreamBuilder::default();
self.bump();
while self.token != token::Eof {
buf.push(self.parse_token_tree()?);
loop {
match self.token.kind {
token::OpenDelim(delim) => buf.push(self.parse_token_tree_open_delim(delim)),
token::CloseDelim(delim) => return Err(self.close_delim_err(delim)),
token::Eof => return Ok(buf.into_token_stream()),
_ => buf.push(self.parse_token_tree_non_delim_non_eof()),
}
}
Ok(buf.into_token_stream())
}
// Parse a stream of tokens into a list of `TokenTree`s, up to a `CloseDelim`.
fn parse_token_trees_until_close_delim(&mut self) -> TokenStream {
let mut buf = TokenStreamBuilder::default();
loop {
if let token::CloseDelim(..) = self.token.kind {
return buf.into_token_stream();
}
match self.parse_token_tree() {
Ok(tree) => buf.push(tree),
Err(mut e) => {
e.emit();
match self.token.kind {
token::OpenDelim(delim) => buf.push(self.parse_token_tree_open_delim(delim)),
token::CloseDelim(..) => return buf.into_token_stream(),
token::Eof => {
self.eof_err().emit();
return buf.into_token_stream();
}
_ => buf.push(self.parse_token_tree_non_delim_non_eof()),
}
}
}
fn parse_token_tree(&mut self) -> PResult<'a, TokenTree> {
let sm = self.string_reader.sess.source_map();
fn eof_err(&mut self) -> PErr<'a> {
let msg = "this file contains an unclosed delimiter";
let mut err = self.string_reader.sess.span_diagnostic.struct_span_err(self.token.span, msg);
for &(_, sp) in &self.open_braces {
err.span_label(sp, "unclosed delimiter");
self.unmatched_braces.push(UnmatchedBrace {
expected_delim: Delimiter::Brace,
found_delim: None,
found_span: self.token.span,
unclosed_span: Some(sp),
candidate_span: None,
});
}
if let Some((delim, _)) = self.open_braces.last() {
if let Some((_, open_sp, close_sp)) =
self.matching_delim_spans.iter().find(|(d, open_sp, close_sp)| {
let sm = self.string_reader.sess.source_map();
if let Some(close_padding) = sm.span_to_margin(*close_sp) {
if let Some(open_padding) = sm.span_to_margin(*open_sp) {
return delim == d && close_padding != open_padding;
}
}
false
})
// these are in reverse order as they get inserted on close, but
{
// we want the last open/first close
err.span_label(*open_sp, "this delimiter might not be properly closed...");
err.span_label(*close_sp, "...as it matches this but it has different indentation");
}
}
err
}
fn parse_token_tree_open_delim(&mut self, open_delim: Delimiter) -> TokenTree {
// The span for beginning of the delimited section
let pre_span = self.token.span;
// Move past the open delimiter.
self.open_braces.push((open_delim, self.token.span));
self.token = self.string_reader.next_token().0;
// Parse the token trees within the delimiters.
// We stop at any delimiter so we can try to recover if the user
// uses an incorrect delimiter.
let tts = self.parse_token_trees_until_close_delim();
// Expand to cover the entire delimited token tree
let delim_span = DelimSpan::from_pair(pre_span, self.token.span);
match self.token.kind {
token::Eof => {
let msg = "this file contains an unclosed delimiter";
let mut err =
self.string_reader.sess.span_diagnostic.struct_span_err(self.token.span, msg);
for &(_, sp) in &self.open_braces {
err.span_label(sp, "unclosed delimiter");
// Correct delimiter.
token::CloseDelim(close_delim) if close_delim == open_delim => {
let (open_brace, open_brace_span) = self.open_braces.pop().unwrap();
let close_brace_span = self.token.span;
if tts.is_empty() {
let empty_block_span = open_brace_span.to(close_brace_span);
let sm = self.string_reader.sess.source_map();
if !sm.is_multiline(empty_block_span) {
// Only track if the block is in the form of `{}`, otherwise it is
// likely that it was written on purpose.
self.last_delim_empty_block_spans.insert(open_delim, empty_block_span);
}
}
//only add braces
if let (Delimiter::Brace, Delimiter::Brace) = (open_brace, open_delim) {
self.matching_block_spans.push((open_brace_span, close_brace_span));
}
if self.open_braces.is_empty() {
// Clear up these spans to avoid suggesting them as we've found
// properly matched delimiters so far for an entire block.
self.matching_delim_spans.clear();
} else {
self.matching_delim_spans.push((open_brace, open_brace_span, close_brace_span));
}
// Move past the closing delimiter.
self.token = self.string_reader.next_token().0;
}
// Incorrect delimiter.
token::CloseDelim(close_delim) => {
let mut unclosed_delimiter = None;
let mut candidate = None;
if self.last_unclosed_found_span != Some(self.token.span) {
// do not complain about the same unclosed delimiter multiple times
self.last_unclosed_found_span = Some(self.token.span);
// This is a conservative error: only report the last unclosed
// delimiter. The previous unclosed delimiters could actually be
// closed! The parser just hasn't gotten to them yet.
if let Some(&(_, sp)) = self.open_braces.last() {
unclosed_delimiter = Some(sp);
};
let sm = self.string_reader.sess.source_map();
if let Some(current_padding) = sm.span_to_margin(self.token.span) {
for (brace, brace_span) in &self.open_braces {
if let Some(padding) = sm.span_to_margin(*brace_span) {
// high likelihood of these two corresponding
if current_padding == padding && brace == &close_delim {
candidate = Some(*brace_span);
}
}
}
}
let (tok, _) = self.open_braces.pop().unwrap();
self.unmatched_braces.push(UnmatchedBrace {
expected_delim: Delimiter::Brace,
found_delim: None,
expected_delim: tok,
found_delim: Some(close_delim),
found_span: self.token.span,
unclosed_span: Some(sp),
candidate_span: None,
unclosed_span: unclosed_delimiter,
candidate_span: candidate,
});
} else {
self.open_braces.pop();
}
if let Some((delim, _)) = self.open_braces.last() {
if let Some((_, open_sp, close_sp)) =
self.matching_delim_spans.iter().find(|(d, open_sp, close_sp)| {
if let Some(close_padding) = sm.span_to_margin(*close_sp) {
if let Some(open_padding) = sm.span_to_margin(*open_sp) {
return delim == d && close_padding != open_padding;
}
}
false
})
// these are in reverse order as they get inserted on close, but
{
// we want the last open/first close
err.span_label(*open_sp, "this delimiter might not be properly closed...");
err.span_label(
*close_sp,
"...as it matches this but it has different indentation",
);
}
// If the incorrect delimiter matches an earlier opening
// delimiter, then don't consume it (it can be used to
// close the earlier one). Otherwise, consume it.
// E.g., we try to recover from:
// fn foo() {
// bar(baz(
// } // Incorrect delimiter but matches the earlier `{`
if !self.open_braces.iter().any(|&(b, _)| b == close_delim) {
self.token = self.string_reader.next_token().0;
}
Err(err)
}
token::OpenDelim(delim) => {
// The span for beginning of the delimited section
let pre_span = self.token.span;
// Parse the open delimiter.
self.open_braces.push((delim, self.token.span));
self.bump();
// Parse the token trees within the delimiters.
// We stop at any delimiter so we can try to recover if the user
// uses an incorrect delimiter.
let tts = self.parse_token_trees_until_close_delim();
// Expand to cover the entire delimited token tree
let delim_span = DelimSpan::from_pair(pre_span, self.token.span);
match self.token.kind {
// Correct delimiter.
token::CloseDelim(d) if d == delim => {
let (open_brace, open_brace_span) = self.open_braces.pop().unwrap();
let close_brace_span = self.token.span;
if tts.is_empty() {
let empty_block_span = open_brace_span.to(close_brace_span);
if !sm.is_multiline(empty_block_span) {
// Only track if the block is in the form of `{}`, otherwise it is
// likely that it was written on purpose.
self.last_delim_empty_block_spans.insert(delim, empty_block_span);
}
}
//only add braces
if let (Delimiter::Brace, Delimiter::Brace) = (open_brace, delim) {
self.matching_block_spans.push((open_brace_span, close_brace_span));
}
if self.open_braces.is_empty() {
// Clear up these spans to avoid suggesting them as we've found
// properly matched delimiters so far for an entire block.
self.matching_delim_spans.clear();
} else {
self.matching_delim_spans.push((
open_brace,
open_brace_span,
close_brace_span,
));
}
// Parse the closing delimiter.
self.bump();
}
// Incorrect delimiter.
token::CloseDelim(other) => {
let mut unclosed_delimiter = None;
let mut candidate = None;
if self.last_unclosed_found_span != Some(self.token.span) {
// do not complain about the same unclosed delimiter multiple times
self.last_unclosed_found_span = Some(self.token.span);
// This is a conservative error: only report the last unclosed
// delimiter. The previous unclosed delimiters could actually be
// closed! The parser just hasn't gotten to them yet.
if let Some(&(_, sp)) = self.open_braces.last() {
unclosed_delimiter = Some(sp);
};
if let Some(current_padding) = sm.span_to_margin(self.token.span) {
for (brace, brace_span) in &self.open_braces {
if let Some(padding) = sm.span_to_margin(*brace_span) {
// high likelihood of these two corresponding
if current_padding == padding && brace == &other {
candidate = Some(*brace_span);
}
}
}
}
let (tok, _) = self.open_braces.pop().unwrap();
self.unmatched_braces.push(UnmatchedBrace {
expected_delim: tok,
found_delim: Some(other),
found_span: self.token.span,
unclosed_span: unclosed_delimiter,
candidate_span: candidate,
});
} else {
self.open_braces.pop();
}
// If the incorrect delimiter matches an earlier opening
// delimiter, then don't consume it (it can be used to
// close the earlier one). Otherwise, consume it.
// E.g., we try to recover from:
// fn foo() {
// bar(baz(
// } // Incorrect delimiter but matches the earlier `{`
if !self.open_braces.iter().any(|&(b, _)| b == other) {
self.bump();
}
}
token::Eof => {
// Silently recover, the EOF token will be seen again
// and an error emitted then. Thus we don't pop from
// self.open_braces here.
}
_ => {}
}
Ok(TokenTree::Delimited(delim_span, delim, tts))
}
token::CloseDelim(delim) => {
// An unexpected closing delimiter (i.e., there is no
// matching opening delimiter).
let token_str = token_to_string(&self.token);
let msg = format!("unexpected closing delimiter: `{}`", token_str);
let mut err =
self.string_reader.sess.span_diagnostic.struct_span_err(self.token.span, &msg);
// Braces are added at the end, so the last element is the biggest block
if let Some(parent) = self.matching_block_spans.last() {
if let Some(span) = self.last_delim_empty_block_spans.remove(&delim) {
// Check if the (empty block) is in the last properly closed block
if (parent.0.to(parent.1)).contains(span) {
err.span_label(
span,
"block is empty, you might have not meant to close it",
);
} else {
err.span_label(parent.0, "this opening brace...");
err.span_label(parent.1, "...matches this closing brace");
}
} else {
err.span_label(parent.0, "this opening brace...");
err.span_label(parent.1, "...matches this closing brace");
}
}
err.span_label(self.token.span, "unexpected closing delimiter");
Err(err)
}
_ => {
let tok = self.token.take();
let mut spacing = self.bump();
if !self.token.is_op() {
spacing = Spacing::Alone;
}
Ok(TokenTree::Token(tok, spacing))
token::Eof => {
// Silently recover, the EOF token will be seen again
// and an error emitted then. Thus we don't pop from
// self.open_braces here.
}
_ => unreachable!(),
}
TokenTree::Delimited(delim_span, open_delim, tts)
}
fn bump(&mut self) -> Spacing {
let (spacing, token) = self.string_reader.next_token();
self.token = token;
spacing
fn close_delim_err(&mut self, delim: Delimiter) -> PErr<'a> {
// An unexpected closing delimiter (i.e., there is no
// matching opening delimiter).
let token_str = token_to_string(&self.token);
let msg = format!("unexpected closing delimiter: `{}`", token_str);
let mut err =
self.string_reader.sess.span_diagnostic.struct_span_err(self.token.span, &msg);
// Braces are added at the end, so the last element is the biggest block
if let Some(parent) = self.matching_block_spans.last() {
if let Some(span) = self.last_delim_empty_block_spans.remove(&delim) {
// Check if the (empty block) is in the last properly closed block
if (parent.0.to(parent.1)).contains(span) {
err.span_label(span, "block is empty, you might have not meant to close it");
} else {
err.span_label(parent.0, "this opening brace...");
err.span_label(parent.1, "...matches this closing brace");
}
} else {
err.span_label(parent.0, "this opening brace...");
err.span_label(parent.1, "...matches this closing brace");
}
}
err.span_label(self.token.span, "unexpected closing delimiter");
err
}
#[inline]
fn parse_token_tree_non_delim_non_eof(&mut self) -> TokenTree {
// `this_spacing` for the returned token refers to whether the token is
// immediately followed by another op token. It is determined by the
// next token: its kind and its `preceded_by_whitespace` status.
let (next_tok, is_next_tok_preceded_by_whitespace) = self.string_reader.next_token();
let this_spacing = if is_next_tok_preceded_by_whitespace || !next_tok.is_op() {
Spacing::Alone
} else {
Spacing::Joint
};
let this_tok = std::mem::replace(&mut self.token, next_tok);
TokenTree::Token(this_tok, this_spacing)
}
}

9
src/librustdoc/html/highlight.rs
View File

@ -13,6 +13,7 @@ use std::collections::VecDeque;
use std::fmt::{Display, Write};
use rustc_data_structures::fx::FxHashMap;
use rustc_lexer::Cursor;
use rustc_lexer::{LiteralKind, TokenKind};
use rustc_span::edition::Edition;
use rustc_span::symbol::Symbol;
@ -408,15 +409,16 @@ enum Highlight<'a> {
struct TokenIter<'a> {
src: &'a str,
cursor: Cursor<'a>,
}
impl<'a> Iterator for TokenIter<'a> {
type Item = (TokenKind, &'a str);
fn next(&mut self) -> Option<(TokenKind, &'a str)> {
if self.src.is_empty() {
let token = self.cursor.advance_token();
if token.kind == TokenKind::Eof {
return None;
}
let token = rustc_lexer::first_token(self.src);
let (text, rest) = self.src.split_at(token.len as usize);
self.src = rest;
Some((token.kind, text))
@ -525,7 +527,7 @@ impl<'a> Classifier<'a> {
/// Takes as argument the source code to HTML-ify, the rust edition to use and the source code
/// file span which will be used later on by the `span_correspondance_map`.
fn new(src: &str, file_span: Span, decoration_info: Option<DecorationInfo>) -> Classifier<'_> {
let tokens = PeekIter::new(TokenIter { src });
let tokens = PeekIter::new(TokenIter { src, cursor: Cursor::new(src) });
let decorations = decoration_info.map(Decorations::new);
Classifier {
tokens,
@ -850,6 +852,7 @@ impl<'a> Classifier<'a> {
Class::Ident(self.new_span(before, text))
}
TokenKind::Lifetime { .. } => Class::Lifetime,
TokenKind::Eof => panic!("Eof in advance"),
};
// Anything that didn't return above is the simple case where we the
// class just spans a single token, so we can use the `string` method.