| use rustc_ast::ast::{self, AttrStyle}; |
| use rustc_ast::token::{self, CommentKind, Token, TokenKind}; |
| use rustc_ast::tokenstream::{Spacing, TokenStream}; |
| use rustc_errors::{error_code, Applicability, DiagnosticBuilder, FatalError, PResult}; |
| use rustc_lexer::unescape::{self, Mode}; |
| use rustc_lexer::{Base, DocStyle, RawStrError}; |
| use rustc_session::lint::builtin::RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX; |
| use rustc_session::lint::BuiltinLintDiagnostics; |
| use rustc_session::parse::ParseSess; |
| use rustc_span::symbol::{sym, Symbol}; |
| use rustc_span::{edition::Edition, BytePos, Pos, Span}; |
| |
| use tracing::debug; |
| |
| mod tokentrees; |
| mod unescape_error_reporting; |
| mod unicode_chars; |
| |
| use unescape_error_reporting::{emit_unescape_error, escaped_char}; |
| |
| #[derive(Clone, Debug)] |
| pub struct UnmatchedBrace { |
| pub expected_delim: token::DelimToken, |
| pub found_delim: Option<token::DelimToken>, |
| pub found_span: Span, |
| pub unclosed_span: Option<Span>, |
| pub candidate_span: Option<Span>, |
| } |
| |
| crate fn parse_token_trees<'a>( |
| sess: &'a ParseSess, |
| src: &'a str, |
| start_pos: BytePos, |
| override_span: Option<Span>, |
| ) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) { |
| StringReader { sess, start_pos, pos: start_pos, end_src_index: src.len(), src, override_span } |
| .into_token_trees() |
| } |
| |
| struct StringReader<'a> { |
| sess: &'a ParseSess, |
| /// Initial position, read-only. |
| start_pos: BytePos, |
| /// The absolute offset within the source_map of the current character. |
| pos: BytePos, |
| /// Stop reading src at this index. |
| end_src_index: usize, |
| /// Source text to tokenize. |
| src: &'a str, |
| override_span: Option<Span>, |
| } |
| |
| impl<'a> StringReader<'a> { |
| fn mk_sp(&self, lo: BytePos, hi: BytePos) -> Span { |
| 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 |
| let start_src_index = self.src_index(self.pos); |
| let text: &str = &self.src[start_src_index..self.end_src_index]; |
| let is_beginning_of_file = self.pos == self.start_pos; |
| if is_beginning_of_file { |
| if let Some(shebang_len) = rustc_lexer::strip_shebang(text) { |
| self.pos = self.pos + BytePos::from_usize(shebang_len); |
| spacing = Spacing::Alone; |
| } |
| } |
| |
| // Skip trivial (whitespace & comments) tokens |
| loop { |
| let start_src_index = self.src_index(self.pos); |
| let text: &str = &self.src[start_src_index..self.end_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 start = self.pos; |
| self.pos = self.pos + BytePos::from_usize(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)); |
| } |
| None => spacing = Spacing::Alone, |
| } |
| } |
| } |
| |
| /// Report a fatal lexical error with a given span. |
| fn fatal_span(&self, sp: Span, m: &str) -> FatalError { |
| self.sess.span_diagnostic.span_fatal(sp, m) |
| } |
| |
| /// Report a lexical error with a given span. |
| fn err_span(&self, sp: Span, m: &str) { |
| self.sess.span_diagnostic.struct_span_err(sp, m).emit(); |
| } |
| |
| /// Report a fatal error spanning [`from_pos`, `to_pos`). |
| fn fatal_span_(&self, from_pos: BytePos, to_pos: BytePos, m: &str) -> FatalError { |
| self.fatal_span(self.mk_sp(from_pos, to_pos), m) |
| } |
| |
| /// Report a lexical error spanning [`from_pos`, `to_pos`). |
| fn err_span_(&self, from_pos: BytePos, to_pos: BytePos, m: &str) { |
| self.err_span(self.mk_sp(from_pos, to_pos), m) |
| } |
| |
| fn struct_fatal_span_char( |
| &self, |
| from_pos: BytePos, |
| to_pos: BytePos, |
| m: &str, |
| c: char, |
| ) -> DiagnosticBuilder<'a> { |
| self.sess |
| .span_diagnostic |
| .struct_span_fatal(self.mk_sp(from_pos, to_pos), &format!("{}: {}", m, escaped_char(c))) |
| } |
| |
| /// 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 doc_style = doc_style?; |
| |
| // 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 { |
| let msg = match doc_style { |
| Some(_) => "unterminated block doc-comment", |
| None => "unterminated block comment", |
| }; |
| let last_bpos = self.pos; |
| self.sess.span_diagnostic.span_fatal_with_code( |
| self.mk_sp(start, last_bpos), |
| msg, |
| error_code!(E0758), |
| ); |
| } |
| |
| // Skip non-doc comments |
| let doc_style = doc_style?; |
| |
| // 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::Literal { kind, suffix_start } => { |
| let suffix_start = start + BytePos(suffix_start as u32); |
| 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(token::Paren), |
| rustc_lexer::TokenKind::CloseParen => token::CloseDelim(token::Paren), |
| rustc_lexer::TokenKind::OpenBrace => token::OpenDelim(token::Brace), |
| rustc_lexer::TokenKind::CloseBrace => token::CloseDelim(token::Brace), |
| rustc_lexer::TokenKind::OpenBracket => token::OpenDelim(token::Bracket), |
| rustc_lexer::TokenKind::CloseBracket => token::CloseDelim(token::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 => { |
| let c = self.str_from(start).chars().next().unwrap(); |
| let mut err = |
| self.struct_fatal_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, |
| content: &str, |
| comment_kind: CommentKind, |
| doc_style: DocStyle, |
| ) -> TokenKind { |
| if content.contains('\r') { |
| for (idx, _) in content.char_indices().filter(|&(_, c)| c == '\r') { |
| self.err_span_( |
| content_start + BytePos(idx as u32), |
| content_start + BytePos(idx as u32 + 1), |
| match comment_kind { |
| CommentKind::Line => "bare CR not allowed in doc-comment", |
| CommentKind::Block => "bare CR not allowed in block doc-comment", |
| }, |
| ); |
| } |
| } |
| |
| let attr_style = match doc_style { |
| DocStyle::Outer => AttrStyle::Outer, |
| DocStyle::Inner => AttrStyle::Inner, |
| }; |
| |
| token::DocComment(comment_kind, attr_style, Symbol::intern(content)) |
| } |
| |
| fn cook_lexer_literal( |
| &self, |
| start: BytePos, |
| suffix_start: BytePos, |
| kind: rustc_lexer::LiteralKind, |
| ) -> (token::LitKind, Symbol) { |
| // prefix means `"` or `br"` or `r###"`, ... |
| let (lit_kind, mode, prefix_len, postfix_len) = match kind { |
| rustc_lexer::LiteralKind::Char { terminated } => { |
| if !terminated { |
| self.sess.span_diagnostic.span_fatal_with_code( |
| self.mk_sp(start, suffix_start), |
| "unterminated character literal", |
| error_code!(E0762), |
| ) |
| } |
| (token::Char, Mode::Char, 1, 1) // ' ' |
| } |
| rustc_lexer::LiteralKind::Byte { terminated } => { |
| if !terminated { |
| self.sess.span_diagnostic.span_fatal_with_code( |
| self.mk_sp(start + BytePos(1), suffix_start), |
| "unterminated byte constant", |
| error_code!(E0763), |
| ) |
| } |
| (token::Byte, Mode::Byte, 2, 1) // b' ' |
| } |
| rustc_lexer::LiteralKind::Str { terminated } => { |
| if !terminated { |
| self.sess.span_diagnostic.span_fatal_with_code( |
| self.mk_sp(start, suffix_start), |
| "unterminated double quote string", |
| error_code!(E0765), |
| ) |
| } |
| (token::Str, Mode::Str, 1, 1) // " " |
| } |
| rustc_lexer::LiteralKind::ByteStr { terminated } => { |
| if !terminated { |
| self.sess.span_diagnostic.span_fatal_with_code( |
| self.mk_sp(start + BytePos(1), suffix_start), |
| "unterminated double quote byte string", |
| error_code!(E0766), |
| ) |
| } |
| (token::ByteStr, Mode::ByteStr, 2, 1) // b" " |
| } |
| rustc_lexer::LiteralKind::RawStr { n_hashes, err } => { |
| self.report_raw_str_error(start, err); |
| let n = u32::from(n_hashes); |
| (token::StrRaw(n_hashes), Mode::RawStr, 2 + n, 1 + n) // r##" "## |
| } |
| rustc_lexer::LiteralKind::RawByteStr { n_hashes, err } => { |
| self.report_raw_str_error(start, err); |
| let n = u32::from(n_hashes); |
| (token::ByteStrRaw(n_hashes), Mode::RawByteStr, 3 + n, 1 + n) // br##" "## |
| } |
| rustc_lexer::LiteralKind::Int { base, empty_int } => { |
| return if empty_int { |
| self.sess |
| .span_diagnostic |
| .struct_span_err_with_code( |
| self.mk_sp(start, suffix_start), |
| "no valid digits found for number", |
| error_code!(E0768), |
| ) |
| .emit(); |
| (token::Integer, sym::integer(0)) |
| } else { |
| self.validate_int_literal(base, start, suffix_start); |
| (token::Integer, self.symbol_from_to(start, suffix_start)) |
| }; |
| } |
| rustc_lexer::LiteralKind::Float { base, empty_exponent } => { |
| if empty_exponent { |
| self.err_span_(start, self.pos, "expected at least one digit in exponent"); |
| } |
| |
| match base { |
| Base::Hexadecimal => self.err_span_( |
| start, |
| suffix_start, |
| "hexadecimal float literal is not supported", |
| ), |
| Base::Octal => { |
| self.err_span_(start, suffix_start, "octal float literal is not supported") |
| } |
| Base::Binary => { |
| self.err_span_(start, suffix_start, "binary float literal is not supported") |
| } |
| _ => (), |
| } |
| |
| let id = self.symbol_from_to(start, suffix_start); |
| return (token::Float, id); |
| } |
| }; |
| let content_start = start + BytePos(prefix_len); |
| let content_end = suffix_start - BytePos(postfix_len); |
| let id = self.symbol_from_to(content_start, content_end); |
| self.validate_literal_escape(mode, content_start, content_end, prefix_len, postfix_len); |
| (lit_kind, id) |
| } |
| |
| #[inline] |
| fn src_index(&self, pos: BytePos) -> usize { |
| (pos - self.start_pos).to_usize() |
| } |
| |
| /// Slice of the source text from `start` up to but excluding `self.pos`, |
| /// meaning the slice does not include the character `self.ch`. |
| fn str_from(&self, start: BytePos) -> &str { |
| self.str_from_to(start, self.pos) |
| } |
| |
| /// As symbol_from, with an explicit endpoint. |
| fn symbol_from_to(&self, start: BytePos, end: BytePos) -> Symbol { |
| debug!("taking an ident from {:?} to {:?}", start, end); |
| Symbol::intern(self.str_from_to(start, end)) |
| } |
| |
| /// Slice of the source text spanning from `start` up to but excluding `end`. |
| fn str_from_to(&self, start: BytePos, end: BytePos) -> &str { |
| &self.src[self.src_index(start)..self.src_index(end)] |
| } |
| |
| fn report_raw_str_error(&self, start: BytePos, opt_err: Option<RawStrError>) { |
| match opt_err { |
| Some(RawStrError::InvalidStarter { bad_char }) => { |
| self.report_non_started_raw_string(start, bad_char) |
| } |
| Some(RawStrError::NoTerminator { expected, found, possible_terminator_offset }) => self |
| .report_unterminated_raw_string(start, expected, possible_terminator_offset, found), |
| Some(RawStrError::TooManyDelimiters { found }) => { |
| self.report_too_many_hashes(start, found) |
| } |
| None => (), |
| } |
| } |
| |
| fn report_non_started_raw_string(&self, start: BytePos, bad_char: char) -> ! { |
| self.struct_fatal_span_char( |
| start, |
| self.pos, |
| "found invalid character; only `#` is allowed in raw string delimitation", |
| bad_char, |
| ) |
| .emit(); |
| FatalError.raise() |
| } |
| |
| fn report_unterminated_raw_string( |
| &self, |
| start: BytePos, |
| n_hashes: usize, |
| possible_offset: Option<usize>, |
| found_terminators: usize, |
| ) -> ! { |
| let mut err = self.sess.span_diagnostic.struct_span_fatal_with_code( |
| self.mk_sp(start, start), |
| "unterminated raw string", |
| error_code!(E0748), |
| ); |
| |
| err.span_label(self.mk_sp(start, start), "unterminated raw string"); |
| |
| if n_hashes > 0 { |
| err.note(&format!( |
| "this raw string should be terminated with `\"{}`", |
| "#".repeat(n_hashes) |
| )); |
| } |
| |
| if let Some(possible_offset) = possible_offset { |
| let lo = start + BytePos(possible_offset as u32); |
| let hi = lo + BytePos(found_terminators as u32); |
| let span = self.mk_sp(lo, hi); |
| err.span_suggestion( |
| span, |
| "consider terminating the string here", |
| "#".repeat(n_hashes), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| |
| err.emit(); |
| FatalError.raise() |
| } |
| |
| // RFC 3101 introduced the idea of (reserved) prefixes. As of Rust 2021, |
| // using a (unknown) prefix is an error. In earlier editions, however, they |
| // only result in a (allowed by default) lint, and are treated as regular |
| // identifier tokens. |
| fn report_unknown_prefix(&self, start: BytePos) { |
| let prefix_span = self.mk_sp(start, self.pos); |
| let msg = format!("prefix `{}` is unknown", self.str_from_to(start, self.pos)); |
| |
| let expn_data = prefix_span.ctxt().outer_expn_data(); |
| |
| if expn_data.edition >= Edition::Edition2021 { |
| // In Rust 2021, this is a hard error. |
| let mut err = self.sess.span_diagnostic.struct_span_err(prefix_span, &msg); |
| err.span_label(prefix_span, "unknown prefix"); |
| if expn_data.is_root() { |
| err.span_suggestion_verbose( |
| prefix_span.shrink_to_hi(), |
| "consider inserting whitespace here", |
| " ".into(), |
| Applicability::MachineApplicable, |
| ); |
| } |
| err.note("prefixed identifiers and literals are reserved since Rust 2021"); |
| err.emit(); |
| } else { |
| // Before Rust 2021, only emit a lint for migration. |
| self.sess.buffer_lint_with_diagnostic( |
| &RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX, |
| prefix_span, |
| ast::CRATE_NODE_ID, |
| &msg, |
| BuiltinLintDiagnostics::ReservedPrefix(prefix_span), |
| ); |
| } |
| } |
| |
| /// Note: It was decided to not add a test case, because it would be too big. |
| /// <https://github.com/rust-lang/rust/pull/50296#issuecomment-392135180> |
| fn report_too_many_hashes(&self, start: BytePos, found: usize) -> ! { |
| self.fatal_span_( |
| start, |
| self.pos, |
| &format!( |
| "too many `#` symbols: raw strings may be delimited \ |
| by up to 65535 `#` symbols, but found {}", |
| found |
| ), |
| ) |
| .raise(); |
| } |
| |
| fn validate_literal_escape( |
| &self, |
| mode: Mode, |
| content_start: BytePos, |
| content_end: BytePos, |
| prefix_len: u32, |
| postfix_len: u32, |
| ) { |
| let lit_content = self.str_from_to(content_start, content_end); |
| unescape::unescape_literal(lit_content, mode, &mut |range, result| { |
| // Here we only check for errors. The actual unescaping is done later. |
| if let Err(err) = result { |
| let span_with_quotes = self |
| .mk_sp(content_start - BytePos(prefix_len), content_end + BytePos(postfix_len)); |
| let (start, end) = (range.start as u32, range.end as u32); |
| let lo = content_start + BytePos(start); |
| let hi = lo + BytePos(end - start); |
| let span = self.mk_sp(lo, hi); |
| emit_unescape_error( |
| &self.sess.span_diagnostic, |
| lit_content, |
| span_with_quotes, |
| span, |
| mode, |
| range, |
| err, |
| ); |
| } |
| }); |
| } |
| |
| fn validate_int_literal(&self, base: Base, content_start: BytePos, content_end: BytePos) { |
| let base = match base { |
| Base::Binary => 2, |
| Base::Octal => 8, |
| _ => return, |
| }; |
| let s = self.str_from_to(content_start + BytePos(2), content_end); |
| for (idx, c) in s.char_indices() { |
| let idx = idx as u32; |
| if c != '_' && c.to_digit(base).is_none() { |
| let lo = content_start + BytePos(2 + idx); |
| let hi = content_start + BytePos(2 + idx + c.len_utf8() as u32); |
| self.err_span_(lo, hi, &format!("invalid digit for a base {} literal", base)); |
| } |
| } |
| } |
| } |
| |
| pub fn nfc_normalize(string: &str) -> Symbol { |
| use unicode_normalization::{is_nfc_quick, IsNormalized, UnicodeNormalization}; |
| match is_nfc_quick(string.chars()) { |
| IsNormalized::Yes => Symbol::intern(string), |
| _ => { |
| let normalized_str: String = string.chars().nfc().collect(); |
| Symbol::intern(&normalized_str) |
| } |
| } |
| } |
