1 pub mod attr;
2 mod attr_wrapper;
3 mod diagnostics;
4 mod expr;
5 mod generics;
6 mod item;
7 mod nonterminal;
8 mod pat;
9 mod path;
10 mod stmt;
11 mod ty;
12
13 use crate::lexer::UnmatchedBrace;
14 pub use attr_wrapper::AttrWrapper;
15 pub use diagnostics::AttemptLocalParseRecovery;
16 use diagnostics::Error;
17 pub use pat::RecoverComma;
18 pub use path::PathStyle;
19
20 use rustc_ast::ptr::P;
21 use rustc_ast::token::{self, DelimToken, Token, TokenKind};
22 use rustc_ast::tokenstream::AttributesData;
23 use rustc_ast::tokenstream::{self, DelimSpan, Spacing};
24 use rustc_ast::tokenstream::{TokenStream, TokenTree};
25 use rustc_ast::AttrId;
26 use rustc_ast::DUMMY_NODE_ID;
27 use rustc_ast::{self as ast, AnonConst, AstLike, AttrStyle, AttrVec, Const, CrateSugar, Extern};
28 use rustc_ast::{Async, Expr, ExprKind, MacArgs, MacDelimiter, Mutability, StrLit, Unsafe};
29 use rustc_ast::{Visibility, VisibilityKind};
30 use rustc_ast_pretty::pprust;
31 use rustc_data_structures::fx::FxHashMap;
32 use rustc_data_structures::sync::Lrc;
33 use rustc_errors::PResult;
34 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, FatalError};
35 use rustc_session::parse::ParseSess;
36 use rustc_span::source_map::{Span, DUMMY_SP};
37 use rustc_span::symbol::{kw, sym, Ident, Symbol};
38 use tracing::debug;
39
40 use std::ops::Range;
41 use std::{cmp, mem, slice};
42
43 bitflags::bitflags! {
44 struct Restrictions: u8 {
45 const STMT_EXPR = 1 << 0;
46 const NO_STRUCT_LITERAL = 1 << 1;
47 const CONST_EXPR = 1 << 2;
48 }
49 }
50
51 #[derive(Clone, Copy, PartialEq, Debug)]
52 enum SemiColonMode {
53 Break,
54 Ignore,
55 Comma,
56 }
57
58 #[derive(Clone, Copy, PartialEq, Debug)]
59 enum BlockMode {
60 Break,
61 Ignore,
62 }
63
64 /// Whether or not we should force collection of tokens for an AST node,
65 /// regardless of whether or not it has attributes
66 pub enum ForceCollect {
67 Yes,
68 No,
69 }
70
71 #[derive(Debug, Eq, PartialEq)]
72 pub enum TrailingToken {
73 None,
74 Semi,
75 /// If the trailing token is a comma, then capture it
76 /// Otherwise, ignore the trailing token
77 MaybeComma,
78 }
79
80 /// Like `maybe_whole_expr`, but for things other than expressions.
81 #[macro_export]
82 macro_rules! maybe_whole {
83 ($p:expr, $constructor:ident, |$x:ident| $e:expr) => {
84 if let token::Interpolated(nt) = &$p.token.kind {
85 if let token::$constructor(x) = &**nt {
86 let $x = x.clone();
87 $p.bump();
88 return Ok($e);
89 }
90 }
91 };
92 }
93
94 /// If the next tokens are ill-formed `$ty::` recover them as `<$ty>::`.
95 #[macro_export]
96 macro_rules! maybe_recover_from_interpolated_ty_qpath {
97 ($self: expr, $allow_qpath_recovery: expr) => {
98 if $allow_qpath_recovery && $self.look_ahead(1, |t| t == &token::ModSep) {
99 if let token::Interpolated(nt) = &$self.token.kind {
100 if let token::NtTy(ty) = &**nt {
101 let ty = ty.clone();
102 $self.bump();
103 return $self.maybe_recover_from_bad_qpath_stage_2($self.prev_token.span, ty);
104 }
105 }
106 }
107 };
108 }
109
110 #[derive(Clone)]
111 pub struct Parser<'a> {
112 pub sess: &'a ParseSess,
113 /// The current token.
114 pub token: Token,
115 /// The spacing for the current token
116 pub token_spacing: Spacing,
117 /// The previous token.
118 pub prev_token: Token,
119 pub capture_cfg: bool,
120 restrictions: Restrictions,
121 expected_tokens: Vec<TokenType>,
122 // Important: This must only be advanced from `next_tok`
123 // to ensure that `token_cursor.num_next_calls` is updated properly
124 token_cursor: TokenCursor,
125 desugar_doc_comments: bool,
126 /// This field is used to keep track of how many left angle brackets we have seen. This is
127 /// required in order to detect extra leading left angle brackets (`<` characters) and error
128 /// appropriately.
129 ///
130 /// See the comments in the `parse_path_segment` function for more details.
131 unmatched_angle_bracket_count: u32,
132 max_angle_bracket_count: u32,
133 /// A list of all unclosed delimiters found by the lexer. If an entry is used for error recovery
134 /// it gets removed from here. Every entry left at the end gets emitted as an independent
135 /// error.
136 pub(super) unclosed_delims: Vec<UnmatchedBrace>,
137 last_unexpected_token_span: Option<Span>,
138 /// Span pointing at the `:` for the last type ascription the parser has seen, and whether it
139 /// looked like it could have been a mistyped path or literal `Option:Some(42)`).
140 pub last_type_ascription: Option<(Span, bool /* likely path typo */)>,
141 /// If present, this `Parser` is not parsing Rust code but rather a macro call.
142 subparser_name: Option<&'static str>,
143 capture_state: CaptureState,
144 }
145
146 /// Indicates a range of tokens that should be replaced by
147 /// the tokens in the provided vector. This is used in two
148 /// places during token collection:
149 ///
150 /// 1. During the parsing of an AST node that may have a `#[derive]`
151 /// attribute, we parse a nested AST node that has `#[cfg]` or `#[cfg_attr]`
152 /// In this case, we use a `ReplaceRange` to replace the entire inner AST node
153 /// with `FlatToken::AttrTarget`, allowing us to perform eager cfg-expansion
154 /// on a `AttrAnnotatedTokenStream`
155 ///
156 /// 2. When we parse an inner attribute while collecting tokens. We
157 /// remove inner attributes from the token stream entirely, and
158 /// instead track them through the `attrs` field on the AST node.
159 /// This allows us to easily manipulate them (for example, removing
160 /// the first macro inner attribute to invoke a proc-macro).
161 /// When create a `TokenStream`, the inner attributes get inserted
162 /// into the proper place in the token stream.
163 pub type ReplaceRange = (Range<u32>, Vec<(FlatToken, Spacing)>);
164
165 /// Controls how we capture tokens. Capturing can be expensive,
166 /// so we try to avoid performing capturing in cases where
167 /// we will never need a `AttrAnnotatedTokenStream`
168 #[derive(Copy, Clone)]
169 pub enum Capturing {
170 /// We aren't performing any capturing - this is the default mode.
171 No,
172 /// We are capturing tokens
173 Yes,
174 }
175
176 #[derive(Clone)]
177 struct CaptureState {
178 capturing: Capturing,
179 replace_ranges: Vec<ReplaceRange>,
180 inner_attr_ranges: FxHashMap<AttrId, ReplaceRange>,
181 }
182
183 impl<'a> Drop for Parser<'a> {
drop(&mut self)184 fn drop(&mut self) {
185 emit_unclosed_delims(&mut self.unclosed_delims, &self.sess);
186 }
187 }
188
189 #[derive(Clone)]
190 struct TokenCursor {
191 frame: TokenCursorFrame,
192 stack: Vec<TokenCursorFrame>,
193 desugar_doc_comments: bool,
194 // Counts the number of calls to `next` or `next_desugared`,
195 // depending on whether `desugar_doc_comments` is set.
196 num_next_calls: usize,
197 // During parsing, we may sometimes need to 'unglue' a
198 // glued token into two component tokens
199 // (e.g. '>>' into '>' and '>), so that the parser
200 // can consume them one at a time. This process
201 // bypasses the normal capturing mechanism
202 // (e.g. `num_next_calls` will not be incremented),
203 // since the 'unglued' tokens due not exist in
204 // the original `TokenStream`.
205 //
206 // If we end up consuming both unglued tokens,
207 // then this is not an issue - we'll end up
208 // capturing the single 'glued' token.
209 //
210 // However, in certain circumstances, we may
211 // want to capture just the first 'unglued' token.
212 // For example, capturing the `Vec<u8>`
213 // in `Option<Vec<u8>>` requires us to unglue
214 // the trailing `>>` token. The `break_last_token`
215 // field is used to track this token - it gets
216 // appended to the captured stream when
217 // we evaluate a `LazyTokenStream`
218 break_last_token: bool,
219 }
220
221 #[derive(Clone)]
222 struct TokenCursorFrame {
223 delim: token::DelimToken,
224 span: DelimSpan,
225 open_delim: bool,
226 tree_cursor: tokenstream::Cursor,
227 close_delim: bool,
228 }
229
230 impl TokenCursorFrame {
new(span: DelimSpan, delim: DelimToken, tts: TokenStream) -> Self231 fn new(span: DelimSpan, delim: DelimToken, tts: TokenStream) -> Self {
232 TokenCursorFrame {
233 delim,
234 span,
235 open_delim: false,
236 tree_cursor: tts.into_trees(),
237 close_delim: false,
238 }
239 }
240 }
241
242 impl TokenCursor {
next(&mut self) -> (Token, Spacing)243 fn next(&mut self) -> (Token, Spacing) {
244 loop {
245 let (tree, spacing) = if !self.frame.open_delim {
246 self.frame.open_delim = true;
247 TokenTree::open_tt(self.frame.span, self.frame.delim).into()
248 } else if let Some(tree) = self.frame.tree_cursor.next_with_spacing() {
249 tree
250 } else if !self.frame.close_delim {
251 self.frame.close_delim = true;
252 TokenTree::close_tt(self.frame.span, self.frame.delim).into()
253 } else if let Some(frame) = self.stack.pop() {
254 self.frame = frame;
255 continue;
256 } else {
257 (TokenTree::Token(Token::new(token::Eof, DUMMY_SP)), Spacing::Alone)
258 };
259
260 match tree {
261 TokenTree::Token(token) => {
262 return (token, spacing);
263 }
264 TokenTree::Delimited(sp, delim, tts) => {
265 let frame = TokenCursorFrame::new(sp, delim, tts);
266 self.stack.push(mem::replace(&mut self.frame, frame));
267 }
268 }
269 }
270 }
271
next_desugared(&mut self) -> (Token, Spacing)272 fn next_desugared(&mut self) -> (Token, Spacing) {
273 let (data, attr_style, sp) = match self.next() {
274 (Token { kind: token::DocComment(_, attr_style, data), span }, _) => {
275 (data, attr_style, span)
276 }
277 tok => return tok,
278 };
279
280 // Searches for the occurrences of `"#*` and returns the minimum number of `#`s
281 // required to wrap the text.
282 let mut num_of_hashes = 0;
283 let mut count = 0;
284 for ch in data.as_str().chars() {
285 count = match ch {
286 '"' => 1,
287 '#' if count > 0 => count + 1,
288 _ => 0,
289 };
290 num_of_hashes = cmp::max(num_of_hashes, count);
291 }
292
293 let delim_span = DelimSpan::from_single(sp);
294 let body = TokenTree::Delimited(
295 delim_span,
296 token::Bracket,
297 [
298 TokenTree::token(token::Ident(sym::doc, false), sp),
299 TokenTree::token(token::Eq, sp),
300 TokenTree::token(TokenKind::lit(token::StrRaw(num_of_hashes), data, None), sp),
301 ]
302 .iter()
303 .cloned()
304 .collect::<TokenStream>(),
305 );
306
307 self.stack.push(mem::replace(
308 &mut self.frame,
309 TokenCursorFrame::new(
310 delim_span,
311 token::NoDelim,
312 if attr_style == AttrStyle::Inner {
313 [TokenTree::token(token::Pound, sp), TokenTree::token(token::Not, sp), body]
314 .iter()
315 .cloned()
316 .collect::<TokenStream>()
317 } else {
318 [TokenTree::token(token::Pound, sp), body]
319 .iter()
320 .cloned()
321 .collect::<TokenStream>()
322 },
323 ),
324 ));
325
326 self.next()
327 }
328 }
329
330 #[derive(Debug, Clone, PartialEq)]
331 enum TokenType {
332 Token(TokenKind),
333 Keyword(Symbol),
334 Operator,
335 Lifetime,
336 Ident,
337 Path,
338 Type,
339 Const,
340 }
341
342 impl TokenType {
to_string(&self) -> String343 fn to_string(&self) -> String {
344 match *self {
345 TokenType::Token(ref t) => format!("`{}`", pprust::token_kind_to_string(t)),
346 TokenType::Keyword(kw) => format!("`{}`", kw),
347 TokenType::Operator => "an operator".to_string(),
348 TokenType::Lifetime => "lifetime".to_string(),
349 TokenType::Ident => "identifier".to_string(),
350 TokenType::Path => "path".to_string(),
351 TokenType::Type => "type".to_string(),
352 TokenType::Const => "a const expression".to_string(),
353 }
354 }
355 }
356
357 #[derive(Copy, Clone, Debug)]
358 enum TokenExpectType {
359 Expect,
360 NoExpect,
361 }
362
363 /// A sequence separator.
364 struct SeqSep {
365 /// The separator token.
366 sep: Option<TokenKind>,
367 /// `true` if a trailing separator is allowed.
368 trailing_sep_allowed: bool,
369 }
370
371 impl SeqSep {
trailing_allowed(t: TokenKind) -> SeqSep372 fn trailing_allowed(t: TokenKind) -> SeqSep {
373 SeqSep { sep: Some(t), trailing_sep_allowed: true }
374 }
375
none() -> SeqSep376 fn none() -> SeqSep {
377 SeqSep { sep: None, trailing_sep_allowed: false }
378 }
379 }
380
381 pub enum FollowedByType {
382 Yes,
383 No,
384 }
385
token_descr_opt(token: &Token) -> Option<&'static str>386 fn token_descr_opt(token: &Token) -> Option<&'static str> {
387 Some(match token.kind {
388 _ if token.is_special_ident() => "reserved identifier",
389 _ if token.is_used_keyword() => "keyword",
390 _ if token.is_unused_keyword() => "reserved keyword",
391 token::DocComment(..) => "doc comment",
392 _ => return None,
393 })
394 }
395
token_descr(token: &Token) -> String396 pub(super) fn token_descr(token: &Token) -> String {
397 let token_str = pprust::token_to_string(token);
398 match token_descr_opt(token) {
399 Some(prefix) => format!("{} `{}`", prefix, token_str),
400 _ => format!("`{}`", token_str),
401 }
402 }
403
404 impl<'a> Parser<'a> {
new( sess: &'a ParseSess, tokens: TokenStream, desugar_doc_comments: bool, subparser_name: Option<&'static str>, ) -> Self405 pub fn new(
406 sess: &'a ParseSess,
407 tokens: TokenStream,
408 desugar_doc_comments: bool,
409 subparser_name: Option<&'static str>,
410 ) -> Self {
411 let mut start_frame = TokenCursorFrame::new(DelimSpan::dummy(), token::NoDelim, tokens);
412 start_frame.open_delim = true;
413 start_frame.close_delim = true;
414
415 let mut parser = Parser {
416 sess,
417 token: Token::dummy(),
418 token_spacing: Spacing::Alone,
419 prev_token: Token::dummy(),
420 capture_cfg: false,
421 restrictions: Restrictions::empty(),
422 expected_tokens: Vec::new(),
423 token_cursor: TokenCursor {
424 frame: start_frame,
425 stack: Vec::new(),
426 num_next_calls: 0,
427 desugar_doc_comments,
428 break_last_token: false,
429 },
430 desugar_doc_comments,
431 unmatched_angle_bracket_count: 0,
432 max_angle_bracket_count: 0,
433 unclosed_delims: Vec::new(),
434 last_unexpected_token_span: None,
435 last_type_ascription: None,
436 subparser_name,
437 capture_state: CaptureState {
438 capturing: Capturing::No,
439 replace_ranges: Vec::new(),
440 inner_attr_ranges: Default::default(),
441 },
442 };
443
444 // Make parser point to the first token.
445 parser.bump();
446
447 parser
448 }
449
next_tok(&mut self, fallback_span: Span) -> (Token, Spacing)450 fn next_tok(&mut self, fallback_span: Span) -> (Token, Spacing) {
451 loop {
452 let (mut next, spacing) = if self.desugar_doc_comments {
453 self.token_cursor.next_desugared()
454 } else {
455 self.token_cursor.next()
456 };
457 self.token_cursor.num_next_calls += 1;
458 // We've retrieved an token from the underlying
459 // cursor, so we no longer need to worry about
460 // an unglued token. See `break_and_eat` for more details
461 self.token_cursor.break_last_token = false;
462 if next.span.is_dummy() {
463 // Tweak the location for better diagnostics, but keep syntactic context intact.
464 next.span = fallback_span.with_ctxt(next.span.ctxt());
465 }
466 if matches!(
467 next.kind,
468 token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim)
469 ) {
470 continue;
471 }
472 return (next, spacing);
473 }
474 }
475
unexpected<T>(&mut self) -> PResult<'a, T>476 pub fn unexpected<T>(&mut self) -> PResult<'a, T> {
477 match self.expect_one_of(&[], &[]) {
478 Err(e) => Err(e),
479 // We can get `Ok(true)` from `recover_closing_delimiter`
480 // which is called in `expected_one_of_not_found`.
481 Ok(_) => FatalError.raise(),
482 }
483 }
484
485 /// Expects and consumes the token `t`. Signals an error if the next token is not `t`.
expect(&mut self, t: &TokenKind) -> PResult<'a, bool >486 pub fn expect(&mut self, t: &TokenKind) -> PResult<'a, bool /* recovered */> {
487 if self.expected_tokens.is_empty() {
488 if self.token == *t {
489 self.bump();
490 Ok(false)
491 } else {
492 self.unexpected_try_recover(t)
493 }
494 } else {
495 self.expect_one_of(slice::from_ref(t), &[])
496 }
497 }
498
499 /// Expect next token to be edible or inedible token. If edible,
500 /// then consume it; if inedible, then return without consuming
501 /// anything. Signal a fatal error if next token is unexpected.
expect_one_of( &mut self, edible: &[TokenKind], inedible: &[TokenKind], ) -> PResult<'a, bool >502 pub fn expect_one_of(
503 &mut self,
504 edible: &[TokenKind],
505 inedible: &[TokenKind],
506 ) -> PResult<'a, bool /* recovered */> {
507 if edible.contains(&self.token.kind) {
508 self.bump();
509 Ok(false)
510 } else if inedible.contains(&self.token.kind) {
511 // leave it in the input
512 Ok(false)
513 } else if self.last_unexpected_token_span == Some(self.token.span) {
514 FatalError.raise();
515 } else {
516 self.expected_one_of_not_found(edible, inedible)
517 }
518 }
519
520 // Public for rustfmt usage.
parse_ident(&mut self) -> PResult<'a, Ident>521 pub fn parse_ident(&mut self) -> PResult<'a, Ident> {
522 self.parse_ident_common(true)
523 }
524
parse_ident_common(&mut self, recover: bool) -> PResult<'a, Ident>525 fn parse_ident_common(&mut self, recover: bool) -> PResult<'a, Ident> {
526 match self.token.ident() {
527 Some((ident, is_raw)) => {
528 if !is_raw && ident.is_reserved() {
529 let mut err = self.expected_ident_found();
530 if recover {
531 err.emit();
532 } else {
533 return Err(err);
534 }
535 }
536 self.bump();
537 Ok(ident)
538 }
539 _ => Err(match self.prev_token.kind {
540 TokenKind::DocComment(..) => {
541 self.span_fatal_err(self.prev_token.span, Error::UselessDocComment)
542 }
543 _ => self.expected_ident_found(),
544 }),
545 }
546 }
547
548 /// Checks if the next token is `tok`, and returns `true` if so.
549 ///
550 /// This method will automatically add `tok` to `expected_tokens` if `tok` is not
551 /// encountered.
check(&mut self, tok: &TokenKind) -> bool552 fn check(&mut self, tok: &TokenKind) -> bool {
553 let is_present = self.token == *tok;
554 if !is_present {
555 self.expected_tokens.push(TokenType::Token(tok.clone()));
556 }
557 is_present
558 }
559
560 /// Consumes a token 'tok' if it exists. Returns whether the given token was present.
eat(&mut self, tok: &TokenKind) -> bool561 pub fn eat(&mut self, tok: &TokenKind) -> bool {
562 let is_present = self.check(tok);
563 if is_present {
564 self.bump()
565 }
566 is_present
567 }
568
569 /// If the next token is the given keyword, returns `true` without eating it.
570 /// An expectation is also added for diagnostics purposes.
check_keyword(&mut self, kw: Symbol) -> bool571 fn check_keyword(&mut self, kw: Symbol) -> bool {
572 self.expected_tokens.push(TokenType::Keyword(kw));
573 self.token.is_keyword(kw)
574 }
575
576 /// If the next token is the given keyword, eats it and returns `true`.
577 /// Otherwise, returns `false`. An expectation is also added for diagnostics purposes.
578 // Public for rustfmt usage.
eat_keyword(&mut self, kw: Symbol) -> bool579 pub fn eat_keyword(&mut self, kw: Symbol) -> bool {
580 if self.check_keyword(kw) {
581 self.bump();
582 true
583 } else {
584 false
585 }
586 }
587
eat_keyword_noexpect(&mut self, kw: Symbol) -> bool588 fn eat_keyword_noexpect(&mut self, kw: Symbol) -> bool {
589 if self.token.is_keyword(kw) {
590 self.bump();
591 true
592 } else {
593 false
594 }
595 }
596
597 /// If the given word is not a keyword, signals an error.
598 /// If the next token is not the given word, signals an error.
599 /// Otherwise, eats it.
expect_keyword(&mut self, kw: Symbol) -> PResult<'a, ()>600 fn expect_keyword(&mut self, kw: Symbol) -> PResult<'a, ()> {
601 if !self.eat_keyword(kw) { self.unexpected() } else { Ok(()) }
602 }
603
604 /// Is the given keyword `kw` followed by a non-reserved identifier?
is_kw_followed_by_ident(&self, kw: Symbol) -> bool605 fn is_kw_followed_by_ident(&self, kw: Symbol) -> bool {
606 self.token.is_keyword(kw) && self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
607 }
608
check_or_expected(&mut self, ok: bool, typ: TokenType) -> bool609 fn check_or_expected(&mut self, ok: bool, typ: TokenType) -> bool {
610 if ok {
611 true
612 } else {
613 self.expected_tokens.push(typ);
614 false
615 }
616 }
617
check_ident(&mut self) -> bool618 fn check_ident(&mut self) -> bool {
619 self.check_or_expected(self.token.is_ident(), TokenType::Ident)
620 }
621
check_path(&mut self) -> bool622 fn check_path(&mut self) -> bool {
623 self.check_or_expected(self.token.is_path_start(), TokenType::Path)
624 }
625
check_type(&mut self) -> bool626 fn check_type(&mut self) -> bool {
627 self.check_or_expected(self.token.can_begin_type(), TokenType::Type)
628 }
629
check_const_arg(&mut self) -> bool630 fn check_const_arg(&mut self) -> bool {
631 self.check_or_expected(self.token.can_begin_const_arg(), TokenType::Const)
632 }
633
check_inline_const(&self, dist: usize) -> bool634 fn check_inline_const(&self, dist: usize) -> bool {
635 self.is_keyword_ahead(dist, &[kw::Const])
636 && self.look_ahead(dist + 1, |t| match t.kind {
637 token::Interpolated(ref nt) => matches!(**nt, token::NtBlock(..)),
638 token::OpenDelim(DelimToken::Brace) => true,
639 _ => false,
640 })
641 }
642
643 /// Checks to see if the next token is either `+` or `+=`.
644 /// Otherwise returns `false`.
check_plus(&mut self) -> bool645 fn check_plus(&mut self) -> bool {
646 self.check_or_expected(
647 self.token.is_like_plus(),
648 TokenType::Token(token::BinOp(token::Plus)),
649 )
650 }
651
652 /// Eats the expected token if it's present possibly breaking
653 /// compound tokens like multi-character operators in process.
654 /// Returns `true` if the token was eaten.
break_and_eat(&mut self, expected: TokenKind) -> bool655 fn break_and_eat(&mut self, expected: TokenKind) -> bool {
656 if self.token.kind == expected {
657 self.bump();
658 return true;
659 }
660 match self.token.kind.break_two_token_op() {
661 Some((first, second)) if first == expected => {
662 let first_span = self.sess.source_map().start_point(self.token.span);
663 let second_span = self.token.span.with_lo(first_span.hi());
664 self.token = Token::new(first, first_span);
665 // Keep track of this token - if we end token capturing now,
666 // we'll want to append this token to the captured stream.
667 //
668 // If we consume any additional tokens, then this token
669 // is not needed (we'll capture the entire 'glued' token),
670 // and `next_tok` will set this field to `None`
671 self.token_cursor.break_last_token = true;
672 // Use the spacing of the glued token as the spacing
673 // of the unglued second token.
674 self.bump_with((Token::new(second, second_span), self.token_spacing));
675 true
676 }
677 _ => {
678 self.expected_tokens.push(TokenType::Token(expected));
679 false
680 }
681 }
682 }
683
684 /// Eats `+` possibly breaking tokens like `+=` in process.
eat_plus(&mut self) -> bool685 fn eat_plus(&mut self) -> bool {
686 self.break_and_eat(token::BinOp(token::Plus))
687 }
688
689 /// Eats `&` possibly breaking tokens like `&&` in process.
690 /// Signals an error if `&` is not eaten.
expect_and(&mut self) -> PResult<'a, ()>691 fn expect_and(&mut self) -> PResult<'a, ()> {
692 if self.break_and_eat(token::BinOp(token::And)) { Ok(()) } else { self.unexpected() }
693 }
694
695 /// Eats `|` possibly breaking tokens like `||` in process.
696 /// Signals an error if `|` was not eaten.
expect_or(&mut self) -> PResult<'a, ()>697 fn expect_or(&mut self) -> PResult<'a, ()> {
698 if self.break_and_eat(token::BinOp(token::Or)) { Ok(()) } else { self.unexpected() }
699 }
700
701 /// Eats `<` possibly breaking tokens like `<<` in process.
eat_lt(&mut self) -> bool702 fn eat_lt(&mut self) -> bool {
703 let ate = self.break_and_eat(token::Lt);
704 if ate {
705 // See doc comment for `unmatched_angle_bracket_count`.
706 self.unmatched_angle_bracket_count += 1;
707 self.max_angle_bracket_count += 1;
708 debug!("eat_lt: (increment) count={:?}", self.unmatched_angle_bracket_count);
709 }
710 ate
711 }
712
713 /// Eats `<` possibly breaking tokens like `<<` in process.
714 /// Signals an error if `<` was not eaten.
expect_lt(&mut self) -> PResult<'a, ()>715 fn expect_lt(&mut self) -> PResult<'a, ()> {
716 if self.eat_lt() { Ok(()) } else { self.unexpected() }
717 }
718
719 /// Eats `>` possibly breaking tokens like `>>` in process.
720 /// Signals an error if `>` was not eaten.
expect_gt(&mut self) -> PResult<'a, ()>721 fn expect_gt(&mut self) -> PResult<'a, ()> {
722 if self.break_and_eat(token::Gt) {
723 // See doc comment for `unmatched_angle_bracket_count`.
724 if self.unmatched_angle_bracket_count > 0 {
725 self.unmatched_angle_bracket_count -= 1;
726 debug!("expect_gt: (decrement) count={:?}", self.unmatched_angle_bracket_count);
727 }
728 Ok(())
729 } else {
730 self.unexpected()
731 }
732 }
733
expect_any_with_type(&mut self, kets: &[&TokenKind], expect: TokenExpectType) -> bool734 fn expect_any_with_type(&mut self, kets: &[&TokenKind], expect: TokenExpectType) -> bool {
735 kets.iter().any(|k| match expect {
736 TokenExpectType::Expect => self.check(k),
737 TokenExpectType::NoExpect => self.token == **k,
738 })
739 }
740
parse_seq_to_before_tokens<T>( &mut self, kets: &[&TokenKind], sep: SeqSep, expect: TokenExpectType, mut f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool , bool )>741 fn parse_seq_to_before_tokens<T>(
742 &mut self,
743 kets: &[&TokenKind],
744 sep: SeqSep,
745 expect: TokenExpectType,
746 mut f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
747 ) -> PResult<'a, (Vec<T>, bool /* trailing */, bool /* recovered */)> {
748 let mut first = true;
749 let mut recovered = false;
750 let mut trailing = false;
751 let mut v = vec![];
752 let unclosed_delims = !self.unclosed_delims.is_empty();
753
754 while !self.expect_any_with_type(kets, expect) {
755 if let token::CloseDelim(..) | token::Eof = self.token.kind {
756 break;
757 }
758 if let Some(ref t) = sep.sep {
759 if first {
760 first = false;
761 } else {
762 match self.expect(t) {
763 Ok(false) => {}
764 Ok(true) => {
765 recovered = true;
766 break;
767 }
768 Err(mut expect_err) => {
769 let sp = self.prev_token.span.shrink_to_hi();
770 let token_str = pprust::token_kind_to_string(t);
771
772 // Attempt to keep parsing if it was a similar separator.
773 if let Some(ref tokens) = t.similar_tokens() {
774 if tokens.contains(&self.token.kind) && !unclosed_delims {
775 self.bump();
776 }
777 }
778
779 // If this was a missing `@` in a binding pattern
780 // bail with a suggestion
781 // https://github.com/rust-lang/rust/issues/72373
782 if self.prev_token.is_ident() && self.token.kind == token::DotDot {
783 let msg = format!(
784 "if you meant to bind the contents of \
785 the rest of the array pattern into `{}`, use `@`",
786 pprust::token_to_string(&self.prev_token)
787 );
788 expect_err
789 .span_suggestion_verbose(
790 self.prev_token.span.shrink_to_hi().until(self.token.span),
791 &msg,
792 " @ ".to_string(),
793 Applicability::MaybeIncorrect,
794 )
795 .emit();
796 break;
797 }
798
799 // Attempt to keep parsing if it was an omitted separator.
800 match f(self) {
801 Ok(t) => {
802 // Parsed successfully, therefore most probably the code only
803 // misses a separator.
804 expect_err
805 .span_suggestion_short(
806 sp,
807 &format!("missing `{}`", token_str),
808 token_str,
809 Applicability::MaybeIncorrect,
810 )
811 .emit();
812
813 v.push(t);
814 continue;
815 }
816 Err(mut e) => {
817 // Parsing failed, therefore it must be something more serious
818 // than just a missing separator.
819 expect_err.emit();
820
821 e.cancel();
822 break;
823 }
824 }
825 }
826 }
827 }
828 }
829 if sep.trailing_sep_allowed && self.expect_any_with_type(kets, expect) {
830 trailing = true;
831 break;
832 }
833
834 let t = f(self)?;
835 v.push(t);
836 }
837
838 Ok((v, trailing, recovered))
839 }
840
841 /// Parses a sequence, not including the closing delimiter. The function
842 /// `f` must consume tokens until reaching the next separator or
843 /// closing bracket.
parse_seq_to_before_end<T>( &mut self, ket: &TokenKind, sep: SeqSep, f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool, bool)>844 fn parse_seq_to_before_end<T>(
845 &mut self,
846 ket: &TokenKind,
847 sep: SeqSep,
848 f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
849 ) -> PResult<'a, (Vec<T>, bool, bool)> {
850 self.parse_seq_to_before_tokens(&[ket], sep, TokenExpectType::Expect, f)
851 }
852
853 /// Parses a sequence, including the closing delimiter. The function
854 /// `f` must consume tokens until reaching the next separator or
855 /// closing bracket.
parse_seq_to_end<T>( &mut self, ket: &TokenKind, sep: SeqSep, f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool )>856 fn parse_seq_to_end<T>(
857 &mut self,
858 ket: &TokenKind,
859 sep: SeqSep,
860 f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
861 ) -> PResult<'a, (Vec<T>, bool /* trailing */)> {
862 let (val, trailing, recovered) = self.parse_seq_to_before_end(ket, sep, f)?;
863 if !recovered {
864 self.eat(ket);
865 }
866 Ok((val, trailing))
867 }
868
869 /// Parses a sequence, including the closing delimiter. The function
870 /// `f` must consume tokens until reaching the next separator or
871 /// closing bracket.
parse_unspanned_seq<T>( &mut self, bra: &TokenKind, ket: &TokenKind, sep: SeqSep, f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool)>872 fn parse_unspanned_seq<T>(
873 &mut self,
874 bra: &TokenKind,
875 ket: &TokenKind,
876 sep: SeqSep,
877 f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
878 ) -> PResult<'a, (Vec<T>, bool)> {
879 self.expect(bra)?;
880 self.parse_seq_to_end(ket, sep, f)
881 }
882
parse_delim_comma_seq<T>( &mut self, delim: DelimToken, f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool)>883 fn parse_delim_comma_seq<T>(
884 &mut self,
885 delim: DelimToken,
886 f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
887 ) -> PResult<'a, (Vec<T>, bool)> {
888 self.parse_unspanned_seq(
889 &token::OpenDelim(delim),
890 &token::CloseDelim(delim),
891 SeqSep::trailing_allowed(token::Comma),
892 f,
893 )
894 }
895
parse_paren_comma_seq<T>( &mut self, f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool)>896 fn parse_paren_comma_seq<T>(
897 &mut self,
898 f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
899 ) -> PResult<'a, (Vec<T>, bool)> {
900 self.parse_delim_comma_seq(token::Paren, f)
901 }
902
903 /// Advance the parser by one token using provided token as the next one.
bump_with(&mut self, (next_token, next_spacing): (Token, Spacing))904 fn bump_with(&mut self, (next_token, next_spacing): (Token, Spacing)) {
905 // Bumping after EOF is a bad sign, usually an infinite loop.
906 if self.prev_token.kind == TokenKind::Eof {
907 let msg = "attempted to bump the parser past EOF (may be stuck in a loop)";
908 self.span_bug(self.token.span, msg);
909 }
910
911 // Update the current and previous tokens.
912 self.prev_token = mem::replace(&mut self.token, next_token);
913 self.token_spacing = next_spacing;
914
915 // Diagnostics.
916 self.expected_tokens.clear();
917 }
918
919 /// Advance the parser by one token.
bump(&mut self)920 pub fn bump(&mut self) {
921 let next_token = self.next_tok(self.token.span);
922 self.bump_with(next_token);
923 }
924
925 /// Look-ahead `dist` tokens of `self.token` and get access to that token there.
926 /// When `dist == 0` then the current token is looked at.
look_ahead<R>(&self, dist: usize, looker: impl FnOnce(&Token) -> R) -> R927 pub fn look_ahead<R>(&self, dist: usize, looker: impl FnOnce(&Token) -> R) -> R {
928 if dist == 0 {
929 return looker(&self.token);
930 }
931
932 let frame = &self.token_cursor.frame;
933 if frame.delim != DelimToken::NoDelim {
934 let all_normal = (0..dist).all(|i| {
935 let token = frame.tree_cursor.look_ahead(i);
936 !matches!(token, Some(TokenTree::Delimited(_, DelimToken::NoDelim, _)))
937 });
938 if all_normal {
939 return match frame.tree_cursor.look_ahead(dist - 1) {
940 Some(tree) => match tree {
941 TokenTree::Token(token) => looker(token),
942 TokenTree::Delimited(dspan, delim, _) => {
943 looker(&Token::new(token::OpenDelim(*delim), dspan.open))
944 }
945 },
946 None => looker(&Token::new(token::CloseDelim(frame.delim), frame.span.close)),
947 };
948 }
949 }
950
951 let mut cursor = self.token_cursor.clone();
952 let mut i = 0;
953 let mut token = Token::dummy();
954 while i < dist {
955 token = cursor.next().0;
956 if matches!(
957 token.kind,
958 token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim)
959 ) {
960 continue;
961 }
962 i += 1;
963 }
964 return looker(&token);
965 }
966
967 /// Returns whether any of the given keywords are `dist` tokens ahead of the current one.
is_keyword_ahead(&self, dist: usize, kws: &[Symbol]) -> bool968 fn is_keyword_ahead(&self, dist: usize, kws: &[Symbol]) -> bool {
969 self.look_ahead(dist, |t| kws.iter().any(|&kw| t.is_keyword(kw)))
970 }
971
972 /// Parses asyncness: `async` or nothing.
parse_asyncness(&mut self) -> Async973 fn parse_asyncness(&mut self) -> Async {
974 if self.eat_keyword(kw::Async) {
975 let span = self.prev_token.uninterpolated_span();
976 Async::Yes { span, closure_id: DUMMY_NODE_ID, return_impl_trait_id: DUMMY_NODE_ID }
977 } else {
978 Async::No
979 }
980 }
981
982 /// Parses unsafety: `unsafe` or nothing.
parse_unsafety(&mut self) -> Unsafe983 fn parse_unsafety(&mut self) -> Unsafe {
984 if self.eat_keyword(kw::Unsafe) {
985 Unsafe::Yes(self.prev_token.uninterpolated_span())
986 } else {
987 Unsafe::No
988 }
989 }
990
991 /// Parses constness: `const` or nothing.
parse_constness(&mut self) -> Const992 fn parse_constness(&mut self) -> Const {
993 // Avoid const blocks to be parsed as const items
994 if self.look_ahead(1, |t| t != &token::OpenDelim(DelimToken::Brace))
995 && self.eat_keyword(kw::Const)
996 {
997 Const::Yes(self.prev_token.uninterpolated_span())
998 } else {
999 Const::No
1000 }
1001 }
1002
1003 /// Parses inline const expressions.
parse_const_block(&mut self, span: Span) -> PResult<'a, P<Expr>>1004 fn parse_const_block(&mut self, span: Span) -> PResult<'a, P<Expr>> {
1005 self.sess.gated_spans.gate(sym::inline_const, span);
1006 self.eat_keyword(kw::Const);
1007 let blk = self.parse_block()?;
1008 let anon_const = AnonConst {
1009 id: DUMMY_NODE_ID,
1010 value: self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new()),
1011 };
1012 let blk_span = anon_const.value.span;
1013 Ok(self.mk_expr(span.to(blk_span), ExprKind::ConstBlock(anon_const), AttrVec::new()))
1014 }
1015
1016 /// Parses mutability (`mut` or nothing).
parse_mutability(&mut self) -> Mutability1017 fn parse_mutability(&mut self) -> Mutability {
1018 if self.eat_keyword(kw::Mut) { Mutability::Mut } else { Mutability::Not }
1019 }
1020
1021 /// Possibly parses mutability (`const` or `mut`).
parse_const_or_mut(&mut self) -> Option<Mutability>1022 fn parse_const_or_mut(&mut self) -> Option<Mutability> {
1023 if self.eat_keyword(kw::Mut) {
1024 Some(Mutability::Mut)
1025 } else if self.eat_keyword(kw::Const) {
1026 Some(Mutability::Not)
1027 } else {
1028 None
1029 }
1030 }
1031
parse_field_name(&mut self) -> PResult<'a, Ident>1032 fn parse_field_name(&mut self) -> PResult<'a, Ident> {
1033 if let token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) = self.token.kind
1034 {
1035 self.expect_no_suffix(self.token.span, "a tuple index", suffix);
1036 self.bump();
1037 Ok(Ident::new(symbol, self.prev_token.span))
1038 } else {
1039 self.parse_ident_common(true)
1040 }
1041 }
1042
parse_mac_args(&mut self) -> PResult<'a, P<MacArgs>>1043 fn parse_mac_args(&mut self) -> PResult<'a, P<MacArgs>> {
1044 self.parse_mac_args_common(true).map(P)
1045 }
1046
parse_attr_args(&mut self) -> PResult<'a, MacArgs>1047 fn parse_attr_args(&mut self) -> PResult<'a, MacArgs> {
1048 self.parse_mac_args_common(false)
1049 }
1050
parse_mac_args_common(&mut self, delimited_only: bool) -> PResult<'a, MacArgs>1051 fn parse_mac_args_common(&mut self, delimited_only: bool) -> PResult<'a, MacArgs> {
1052 Ok(
1053 if self.check(&token::OpenDelim(DelimToken::Paren))
1054 || self.check(&token::OpenDelim(DelimToken::Bracket))
1055 || self.check(&token::OpenDelim(DelimToken::Brace))
1056 {
1057 match self.parse_token_tree() {
1058 TokenTree::Delimited(dspan, delim, tokens) =>
1059 // We've confirmed above that there is a delimiter so unwrapping is OK.
1060 {
1061 MacArgs::Delimited(dspan, MacDelimiter::from_token(delim).unwrap(), tokens)
1062 }
1063 _ => unreachable!(),
1064 }
1065 } else if !delimited_only {
1066 if self.eat(&token::Eq) {
1067 let eq_span = self.prev_token.span;
1068 let mut is_interpolated_expr = false;
1069 if let token::Interpolated(nt) = &self.token.kind {
1070 if let token::NtExpr(..) = **nt {
1071 is_interpolated_expr = true;
1072 }
1073 }
1074
1075 // Collect tokens because they are used during lowering to HIR.
1076 let expr = self.parse_expr_force_collect()?;
1077 let span = expr.span;
1078
1079 match &expr.kind {
1080 // Not gated to supporte things like `doc = $expr` that work on stable.
1081 _ if is_interpolated_expr => {}
1082 ExprKind::Lit(lit) if lit.kind.is_unsuffixed() => {}
1083 _ => self.sess.gated_spans.gate(sym::extended_key_value_attributes, span),
1084 }
1085
1086 let token_kind = token::Interpolated(Lrc::new(token::NtExpr(expr)));
1087 MacArgs::Eq(eq_span, Token::new(token_kind, span))
1088 } else {
1089 MacArgs::Empty
1090 }
1091 } else {
1092 return self.unexpected();
1093 },
1094 )
1095 }
1096
parse_or_use_outer_attributes( &mut self, already_parsed_attrs: Option<AttrWrapper>, ) -> PResult<'a, AttrWrapper>1097 fn parse_or_use_outer_attributes(
1098 &mut self,
1099 already_parsed_attrs: Option<AttrWrapper>,
1100 ) -> PResult<'a, AttrWrapper> {
1101 if let Some(attrs) = already_parsed_attrs {
1102 Ok(attrs)
1103 } else {
1104 self.parse_outer_attributes()
1105 }
1106 }
1107
1108 /// Parses a single token tree from the input.
parse_token_tree(&mut self) -> TokenTree1109 pub(crate) fn parse_token_tree(&mut self) -> TokenTree {
1110 match self.token.kind {
1111 token::OpenDelim(..) => {
1112 let depth = self.token_cursor.stack.len();
1113
1114 // We keep advancing the token cursor until we hit
1115 // the matching `CloseDelim` token.
1116 while !(depth == self.token_cursor.stack.len()
1117 && matches!(self.token.kind, token::CloseDelim(_)))
1118 {
1119 // Advance one token at a time, so `TokenCursor::next()`
1120 // can capture these tokens if necessary.
1121 self.bump();
1122 }
1123 // We are still inside the frame corresponding
1124 // to the delimited stream we captured, so grab
1125 // the tokens from this frame.
1126 let frame = &self.token_cursor.frame;
1127 let stream = frame.tree_cursor.stream.clone();
1128 let span = frame.span;
1129 let delim = frame.delim;
1130 // Consume close delimiter
1131 self.bump();
1132 TokenTree::Delimited(span, delim, stream)
1133 }
1134 token::CloseDelim(_) | token::Eof => unreachable!(),
1135 _ => {
1136 self.bump();
1137 TokenTree::Token(self.prev_token.clone())
1138 }
1139 }
1140 }
1141
1142 /// Parses a stream of tokens into a list of `TokenTree`s, up to EOF.
parse_all_token_trees(&mut self) -> PResult<'a, Vec<TokenTree>>1143 pub fn parse_all_token_trees(&mut self) -> PResult<'a, Vec<TokenTree>> {
1144 let mut tts = Vec::new();
1145 while self.token != token::Eof {
1146 tts.push(self.parse_token_tree());
1147 }
1148 Ok(tts)
1149 }
1150
parse_tokens(&mut self) -> TokenStream1151 pub fn parse_tokens(&mut self) -> TokenStream {
1152 let mut result = Vec::new();
1153 loop {
1154 match self.token.kind {
1155 token::Eof | token::CloseDelim(..) => break,
1156 _ => result.push(self.parse_token_tree().into()),
1157 }
1158 }
1159 TokenStream::new(result)
1160 }
1161
1162 /// Evaluates the closure with restrictions in place.
1163 ///
1164 /// Afters the closure is evaluated, restrictions are reset.
with_res<T>(&mut self, res: Restrictions, f: impl FnOnce(&mut Self) -> T) -> T1165 fn with_res<T>(&mut self, res: Restrictions, f: impl FnOnce(&mut Self) -> T) -> T {
1166 let old = self.restrictions;
1167 self.restrictions = res;
1168 let res = f(self);
1169 self.restrictions = old;
1170 res
1171 }
1172
is_crate_vis(&self) -> bool1173 fn is_crate_vis(&self) -> bool {
1174 self.token.is_keyword(kw::Crate) && self.look_ahead(1, |t| t != &token::ModSep)
1175 }
1176
1177 /// Parses `pub`, `pub(crate)` and `pub(in path)` plus shortcuts `crate` for `pub(crate)`,
1178 /// `pub(self)` for `pub(in self)` and `pub(super)` for `pub(in super)`.
1179 /// If the following element can't be a tuple (i.e., it's a function definition), then
1180 /// it's not a tuple struct field), and the contents within the parentheses isn't valid,
1181 /// so emit a proper diagnostic.
1182 // Public for rustfmt usage.
parse_visibility(&mut self, fbt: FollowedByType) -> PResult<'a, Visibility>1183 pub fn parse_visibility(&mut self, fbt: FollowedByType) -> PResult<'a, Visibility> {
1184 maybe_whole!(self, NtVis, |x| x);
1185
1186 self.expected_tokens.push(TokenType::Keyword(kw::Crate));
1187 if self.is_crate_vis() {
1188 self.bump(); // `crate`
1189 self.sess.gated_spans.gate(sym::crate_visibility_modifier, self.prev_token.span);
1190 return Ok(Visibility {
1191 span: self.prev_token.span,
1192 kind: VisibilityKind::Crate(CrateSugar::JustCrate),
1193 tokens: None,
1194 });
1195 }
1196
1197 if !self.eat_keyword(kw::Pub) {
1198 // We need a span for our `Spanned<VisibilityKind>`, but there's inherently no
1199 // keyword to grab a span from for inherited visibility; an empty span at the
1200 // beginning of the current token would seem to be the "Schelling span".
1201 return Ok(Visibility {
1202 span: self.token.span.shrink_to_lo(),
1203 kind: VisibilityKind::Inherited,
1204 tokens: None,
1205 });
1206 }
1207 let lo = self.prev_token.span;
1208
1209 if self.check(&token::OpenDelim(token::Paren)) {
1210 // We don't `self.bump()` the `(` yet because this might be a struct definition where
1211 // `()` or a tuple might be allowed. For example, `struct Struct(pub (), pub (usize));`.
1212 // Because of this, we only `bump` the `(` if we're assured it is appropriate to do so
1213 // by the following tokens.
1214 if self.is_keyword_ahead(1, &[kw::Crate]) && self.look_ahead(2, |t| t != &token::ModSep)
1215 // account for `pub(crate::foo)`
1216 {
1217 // Parse `pub(crate)`.
1218 self.bump(); // `(`
1219 self.bump(); // `crate`
1220 self.expect(&token::CloseDelim(token::Paren))?; // `)`
1221 let vis = VisibilityKind::Crate(CrateSugar::PubCrate);
1222 return Ok(Visibility {
1223 span: lo.to(self.prev_token.span),
1224 kind: vis,
1225 tokens: None,
1226 });
1227 } else if self.is_keyword_ahead(1, &[kw::In]) {
1228 // Parse `pub(in path)`.
1229 self.bump(); // `(`
1230 self.bump(); // `in`
1231 let path = self.parse_path(PathStyle::Mod)?; // `path`
1232 self.expect(&token::CloseDelim(token::Paren))?; // `)`
1233 let vis = VisibilityKind::Restricted { path: P(path), id: ast::DUMMY_NODE_ID };
1234 return Ok(Visibility {
1235 span: lo.to(self.prev_token.span),
1236 kind: vis,
1237 tokens: None,
1238 });
1239 } else if self.look_ahead(2, |t| t == &token::CloseDelim(token::Paren))
1240 && self.is_keyword_ahead(1, &[kw::Super, kw::SelfLower])
1241 {
1242 // Parse `pub(self)` or `pub(super)`.
1243 self.bump(); // `(`
1244 let path = self.parse_path(PathStyle::Mod)?; // `super`/`self`
1245 self.expect(&token::CloseDelim(token::Paren))?; // `)`
1246 let vis = VisibilityKind::Restricted { path: P(path), id: ast::DUMMY_NODE_ID };
1247 return Ok(Visibility {
1248 span: lo.to(self.prev_token.span),
1249 kind: vis,
1250 tokens: None,
1251 });
1252 } else if let FollowedByType::No = fbt {
1253 // Provide this diagnostic if a type cannot follow;
1254 // in particular, if this is not a tuple struct.
1255 self.recover_incorrect_vis_restriction()?;
1256 // Emit diagnostic, but continue with public visibility.
1257 }
1258 }
1259
1260 Ok(Visibility { span: lo, kind: VisibilityKind::Public, tokens: None })
1261 }
1262
1263 /// Recovery for e.g. `pub(something) fn ...` or `struct X { pub(something) y: Z }`
recover_incorrect_vis_restriction(&mut self) -> PResult<'a, ()>1264 fn recover_incorrect_vis_restriction(&mut self) -> PResult<'a, ()> {
1265 self.bump(); // `(`
1266 let path = self.parse_path(PathStyle::Mod)?;
1267 self.expect(&token::CloseDelim(token::Paren))?; // `)`
1268
1269 let msg = "incorrect visibility restriction";
1270 let suggestion = r##"some possible visibility restrictions are:
1271 `pub(crate)`: visible only on the current crate
1272 `pub(super)`: visible only in the current module's parent
1273 `pub(in path::to::module)`: visible only on the specified path"##;
1274
1275 let path_str = pprust::path_to_string(&path);
1276
1277 struct_span_err!(self.sess.span_diagnostic, path.span, E0704, "{}", msg)
1278 .help(suggestion)
1279 .span_suggestion(
1280 path.span,
1281 &format!("make this visible only to module `{}` with `in`", path_str),
1282 format!("in {}", path_str),
1283 Applicability::MachineApplicable,
1284 )
1285 .emit();
1286
1287 Ok(())
1288 }
1289
1290 /// Parses `extern string_literal?`.
parse_extern(&mut self) -> Extern1291 fn parse_extern(&mut self) -> Extern {
1292 if self.eat_keyword(kw::Extern) { Extern::from_abi(self.parse_abi()) } else { Extern::None }
1293 }
1294
1295 /// Parses a string literal as an ABI spec.
parse_abi(&mut self) -> Option<StrLit>1296 fn parse_abi(&mut self) -> Option<StrLit> {
1297 match self.parse_str_lit() {
1298 Ok(str_lit) => Some(str_lit),
1299 Err(Some(lit)) => match lit.kind {
1300 ast::LitKind::Err(_) => None,
1301 _ => {
1302 self.struct_span_err(lit.span, "non-string ABI literal")
1303 .span_suggestion(
1304 lit.span,
1305 "specify the ABI with a string literal",
1306 "\"C\"".to_string(),
1307 Applicability::MaybeIncorrect,
1308 )
1309 .emit();
1310 None
1311 }
1312 },
1313 Err(None) => None,
1314 }
1315 }
1316
collect_tokens_no_attrs<R: AstLike>( &mut self, f: impl FnOnce(&mut Self) -> PResult<'a, R>, ) -> PResult<'a, R>1317 pub fn collect_tokens_no_attrs<R: AstLike>(
1318 &mut self,
1319 f: impl FnOnce(&mut Self) -> PResult<'a, R>,
1320 ) -> PResult<'a, R> {
1321 // The only reason to call `collect_tokens_no_attrs` is if you want tokens, so use
1322 // `ForceCollect::Yes`
1323 self.collect_tokens_trailing_token(
1324 AttrWrapper::empty(),
1325 ForceCollect::Yes,
1326 |this, _attrs| Ok((f(this)?, TrailingToken::None)),
1327 )
1328 }
1329
1330 /// `::{` or `::*`
is_import_coupler(&mut self) -> bool1331 fn is_import_coupler(&mut self) -> bool {
1332 self.check(&token::ModSep)
1333 && self.look_ahead(1, |t| {
1334 *t == token::OpenDelim(token::Brace) || *t == token::BinOp(token::Star)
1335 })
1336 }
1337
clear_expected_tokens(&mut self)1338 pub fn clear_expected_tokens(&mut self) {
1339 self.expected_tokens.clear();
1340 }
1341 }
1342
make_unclosed_delims_error( unmatched: UnmatchedBrace, sess: &ParseSess, ) -> Option<DiagnosticBuilder<'_>>1343 crate fn make_unclosed_delims_error(
1344 unmatched: UnmatchedBrace,
1345 sess: &ParseSess,
1346 ) -> Option<DiagnosticBuilder<'_>> {
1347 // `None` here means an `Eof` was found. We already emit those errors elsewhere, we add them to
1348 // `unmatched_braces` only for error recovery in the `Parser`.
1349 let found_delim = unmatched.found_delim?;
1350 let mut err = sess.span_diagnostic.struct_span_err(
1351 unmatched.found_span,
1352 &format!(
1353 "mismatched closing delimiter: `{}`",
1354 pprust::token_kind_to_string(&token::CloseDelim(found_delim)),
1355 ),
1356 );
1357 err.span_label(unmatched.found_span, "mismatched closing delimiter");
1358 if let Some(sp) = unmatched.candidate_span {
1359 err.span_label(sp, "closing delimiter possibly meant for this");
1360 }
1361 if let Some(sp) = unmatched.unclosed_span {
1362 err.span_label(sp, "unclosed delimiter");
1363 }
1364 Some(err)
1365 }
1366
emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, sess: &ParseSess)1367 pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, sess: &ParseSess) {
1368 *sess.reached_eof.borrow_mut() |=
1369 unclosed_delims.iter().any(|unmatched_delim| unmatched_delim.found_delim.is_none());
1370 for unmatched in unclosed_delims.drain(..) {
1371 if let Some(mut e) = make_unclosed_delims_error(unmatched, sess) {
1372 e.emit();
1373 }
1374 }
1375 }
1376
1377 /// A helper struct used when building a `AttrAnnotatedTokenStream` from
1378 /// a `LazyTokenStream`. Both delimiter and non-delimited tokens
1379 /// are stored as `FlatToken::Token`. A vector of `FlatToken`s
1380 /// is then 'parsed' to build up a `AttrAnnotatedTokenStream` with nested
1381 /// `AttrAnnotatedTokenTree::Delimited` tokens
1382 #[derive(Debug, Clone)]
1383 pub enum FlatToken {
1384 /// A token - this holds both delimiter (e.g. '{' and '}')
1385 /// and non-delimiter tokens
1386 Token(Token),
1387 /// Holds the `AttributesData` for an AST node. The
1388 /// `AttributesData` is inserted directly into the
1389 /// constructed `AttrAnnotatedTokenStream` as
1390 /// a `AttrAnnotatedTokenTree::Attributes`
1391 AttrTarget(AttributesData),
1392 /// A special 'empty' token that is ignored during the conversion
1393 /// to a `AttrAnnotatedTokenStream`. This is used to simplify the
1394 /// handling of replace ranges.
1395 Empty,
1396 }
1397