compiler/rustc_parse/src/parser/stmt.rs

   1 use super::attr::DEFAULT_INNER_ATTR_FORBIDDEN;
   2 use super::diagnostics::{AttemptLocalParseRecovery, Error};
   3 use super::expr::LhsExpr;
   4 use super::pat::RecoverComma;
   5 use super::path::PathStyle;
   6 use super::TrailingToken;
   7 use super::{
   8     AttrWrapper, BlockMode, FnParseMode, ForceCollect, Parser, Restrictions, SemiColonMode,
   9 };
  10 use crate::maybe_whole;
  11
  12 use rustc_ast as ast;
  13 use rustc_ast::ptr::P;
  14 use rustc_ast::token::{self, Delimiter, TokenKind};
  15 use rustc_ast::util::classify;
  16 use rustc_ast::{
  17     AstLike, AttrStyle, AttrVec, Attribute, LocalKind, MacCall, MacCallStmt, MacStmtStyle,
  18 };
  19 use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, Local, Stmt};
  20 use rustc_ast::{StmtKind, DUMMY_NODE_ID};
  21 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
  22 use rustc_span::source_map::{BytePos, Span};
  23 use rustc_span::symbol::{kw, sym};
  24
  25 use std::mem;
  26
  27 impl<'a> Parser<'a> {
  28     /// Parses a statement. This stops just before trailing semicolons on everything but items.
  29     /// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
  30     // Public for rustfmt usage.
  31     pub fn parse_stmt(&mut self, force_collect: ForceCollect) -> PResult<'a, Option<Stmt>> {
  32         Ok(self.parse_stmt_without_recovery(false, force_collect).unwrap_or_else(|mut e| {
  33             e.emit();
  34             self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
  35             None
  36         }))
  37     }
  38
  39     /// If `force_capture` is true, forces collection of tokens regardless of whether
  40     /// or not we have attributes
  41     crate fn parse_stmt_without_recovery(
  42         &mut self,
  43         capture_semi: bool,
  44         force_collect: ForceCollect,
  45     ) -> PResult<'a, Option<Stmt>> {
  46         let attrs = self.parse_outer_attributes()?;
  47         let lo = self.token.span;
  48
  49         // Don't use `maybe_whole` so that we have precise control
  50         // over when we bump the parser
  51         if let token::Interpolated(nt) = &self.token.kind && let token::NtStmt(stmt) = &**nt {
  52             let mut stmt = stmt.clone();
  53             self.bump();
  54             stmt.visit_attrs(|stmt_attrs| {
  55                 attrs.prepend_to_nt_inner(stmt_attrs);
  56             });
  57             return Ok(Some(stmt.into_inner()));
  58         }
  59
  60         Ok(Some(if self.token.is_keyword(kw::Let) {
  61             self.parse_local_mk(lo, attrs, capture_semi, force_collect)?
  62         } else if self.is_kw_followed_by_ident(kw::Mut) {
  63             self.recover_stmt_local(lo, attrs, "missing keyword", "let mut")?
  64         } else if self.is_kw_followed_by_ident(kw::Auto) {
  65             self.bump(); // `auto`
  66             let msg = "write `let` instead of `auto` to introduce a new variable";
  67             self.recover_stmt_local(lo, attrs, msg, "let")?
  68         } else if self.is_kw_followed_by_ident(sym::var) {
  69             self.bump(); // `var`
  70             let msg = "write `let` instead of `var` to introduce a new variable";
  71             self.recover_stmt_local(lo, attrs, msg, "let")?
  72         } else if self.check_path() && !self.token.is_qpath_start() && !self.is_path_start_item() {
  73             // We have avoided contextual keywords like `union`, items with `crate` visibility,
  74             // or `auto trait` items. We aim to parse an arbitrary path `a::b` but not something
  75             // that starts like a path (1 token), but it fact not a path.
  76             // Also, we avoid stealing syntax from `parse_item_`.
  77             if force_collect == ForceCollect::Yes {
  78                 self.collect_tokens_no_attrs(|this| this.parse_stmt_path_start(lo, attrs))
  79             } else {
  80                 self.parse_stmt_path_start(lo, attrs)
  81             }?
  82         } else if let Some(item) = self.parse_item_common(
  83             attrs.clone(),
  84             false,
  85             true,
  86             FnParseMode { req_name: |_| true, req_body: true },
  87             force_collect,
  88         )? {
  89             // FIXME: Bad copy of attrs
  90             self.mk_stmt(lo.to(item.span), StmtKind::Item(P(item)))
  91         } else if self.eat(&token::Semi) {
  92             // Do not attempt to parse an expression if we're done here.
  93             self.error_outer_attrs(&attrs.take_for_recovery());
  94             self.mk_stmt(lo, StmtKind::Empty)
  95         } else if self.token != token::CloseDelim(Delimiter::Brace) {
  96             // Remainder are line-expr stmts.
  97             let e = if force_collect == ForceCollect::Yes {
  98                 self.collect_tokens_no_attrs(|this| {
  99                     this.parse_expr_res(Restrictions::STMT_EXPR, Some(attrs))
 100                 })
 101             } else {
 102                 self.parse_expr_res(Restrictions::STMT_EXPR, Some(attrs))
 103             }?;
 104             if matches!(e.kind, ExprKind::Assign(..)) && self.eat_keyword(kw::Else) {
 105                 let bl = self.parse_block()?;
 106                 // Destructuring assignment ... else.
 107                 // This is not allowed, but point it out in a nice way.
 108                 let mut err = self.struct_span_err(
 109                     e.span.to(bl.span),
 110                     "<assignment> ... else { ... } is not allowed",
 111                 );
 112                 err.emit();
 113             }
 114             self.mk_stmt(lo.to(e.span), StmtKind::Expr(e))
 115         } else {
 116             self.error_outer_attrs(&attrs.take_for_recovery());
 117             return Ok(None);
 118         }))
 119     }
 120
 121     fn parse_stmt_path_start(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> {
 122         let stmt = self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
 123             let path = this.parse_path(PathStyle::Expr)?;
 124
 125             if this.eat(&token::Not) {
 126                 let stmt_mac = this.parse_stmt_mac(lo, attrs.into(), path)?;
 127                 if this.token == token::Semi {
 128                     return Ok((stmt_mac, TrailingToken::Semi));
 129                 } else {
 130                     return Ok((stmt_mac, TrailingToken::None));
 131                 }
 132             }
 133
 134             let expr = if this.eat(&token::OpenDelim(Delimiter::Brace)) {
 135                 this.parse_struct_expr(None, path, AttrVec::new(), true)?
 136             } else {
 137                 let hi = this.prev_token.span;
 138                 this.mk_expr(lo.to(hi), ExprKind::Path(None, path), AttrVec::new())
 139             };
 140
 141             let expr = this.with_res(Restrictions::STMT_EXPR, |this| {
 142                 this.parse_dot_or_call_expr_with(expr, lo, attrs)
 143             })?;
 144             // `DUMMY_SP` will get overwritten later in this function
 145             Ok((this.mk_stmt(rustc_span::DUMMY_SP, StmtKind::Expr(expr)), TrailingToken::None))
 146         })?;
 147
 148         if let StmtKind::Expr(expr) = stmt.kind {
 149             // Perform this outside of the `collect_tokens_trailing_token` closure,
 150             // since our outer attributes do not apply to this part of the expression
 151             let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
 152                 this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
 153             })?;
 154             Ok(self.mk_stmt(lo.to(self.prev_token.span), StmtKind::Expr(expr)))
 155         } else {
 156             Ok(stmt)
 157         }
 158     }
 159
 160     /// Parses a statement macro `mac!(args)` provided a `path` representing `mac`.
 161     /// At this point, the `!` token after the path has already been eaten.
 162     fn parse_stmt_mac(&mut self, lo: Span, attrs: AttrVec, path: ast::Path) -> PResult<'a, Stmt> {
 163         let args = self.parse_mac_args()?;
 164         let delim = args.delim();
 165         let hi = self.prev_token.span;
 166
 167         let style = match delim {
 168             Some(Delimiter::Brace) => MacStmtStyle::Braces,
 169             Some(_) => MacStmtStyle::NoBraces,
 170             None => unreachable!(),
 171         };
 172
 173         let mac = MacCall { path, args, prior_type_ascription: self.last_type_ascription };
 174
 175         let kind = if (style == MacStmtStyle::Braces
 176             && self.token != token::Dot
 177             && self.token != token::Question)
 178             || self.token == token::Semi
 179             || self.token == token::Eof
 180         {
 181             StmtKind::MacCall(P(MacCallStmt { mac, style, attrs, tokens: None }))
 182         } else {
 183             // Since none of the above applied, this is an expression statement macro.
 184             let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac), AttrVec::new());
 185             let e = self.maybe_recover_from_bad_qpath(e, true)?;
 186             let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
 187             let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
 188             StmtKind::Expr(e)
 189         };
 190         Ok(self.mk_stmt(lo.to(hi), kind))
 191     }
 192
 193     /// Error on outer attributes in this context.
 194     /// Also error if the previous token was a doc comment.
 195     fn error_outer_attrs(&self, attrs: &[Attribute]) {
 196         if let [.., last] = attrs {
 197             if last.is_doc_comment() {
 198                 self.span_err(last.span, Error::UselessDocComment).emit();
 199             } else if attrs.iter().any(|a| a.style == AttrStyle::Outer) {
 200                 self.struct_span_err(last.span, "expected statement after outer attribute").emit();
 201             }
 202         }
 203     }
 204
 205     fn recover_stmt_local(
 206         &mut self,
 207         lo: Span,
 208         attrs: AttrWrapper,
 209         msg: &str,
 210         sugg: &str,
 211     ) -> PResult<'a, Stmt> {
 212         let stmt = self.recover_local_after_let(lo, attrs)?;
 213         self.struct_span_err(lo, "invalid variable declaration")
 214             .span_suggestion(lo, msg, sugg.to_string(), Applicability::MachineApplicable)
 215             .emit();
 216         Ok(stmt)
 217     }
 218
 219     fn parse_local_mk(
 220         &mut self,
 221         lo: Span,
 222         attrs: AttrWrapper,
 223         capture_semi: bool,
 224         force_collect: ForceCollect,
 225     ) -> PResult<'a, Stmt> {
 226         self.collect_tokens_trailing_token(attrs, force_collect, |this, attrs| {
 227             this.expect_keyword(kw::Let)?;
 228             let local = this.parse_local(attrs.into())?;
 229             let trailing = if capture_semi && this.token.kind == token::Semi {
 230                 TrailingToken::Semi
 231             } else {
 232                 TrailingToken::None
 233             };
 234             Ok((this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Local(local)), trailing))
 235         })
 236     }
 237
 238     fn recover_local_after_let(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> {
 239         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
 240             let local = this.parse_local(attrs.into())?;
 241             // FIXME - maybe capture semicolon in recovery?
 242             Ok((
 243                 this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Local(local)),
 244                 TrailingToken::None,
 245             ))
 246         })
 247     }
 248
 249     /// Parses a local variable declaration.
 250     fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P<Local>> {
 251         let lo = self.prev_token.span;
 252         let (pat, colon) = self.parse_pat_before_ty(None, RecoverComma::Yes, "`let` bindings")?;
 253
 254         let (err, ty) = if colon {
 255             // Save the state of the parser before parsing type normally, in case there is a `:`
 256             // instead of an `=` typo.
 257             let parser_snapshot_before_type = self.clone();
 258             let colon_sp = self.prev_token.span;
 259             match self.parse_ty() {
 260                 Ok(ty) => (None, Some(ty)),
 261                 Err(mut err) => {
 262                     if let Ok(snip) = self.span_to_snippet(pat.span) {
 263                         err.span_label(pat.span, format!("while parsing the type for `{}`", snip));
 264                     }
 265                     // we use noexpect here because we don't actually expect Eq to be here
 266                     // but we are still checking for it in order to be able to handle it if
 267                     // it is there
 268                     let err = if self.check_noexpect(&token::Eq) {
 269                         err.emit();
 270                         None
 271                     } else {
 272                         // Rewind to before attempting to parse the type and continue parsing.
 273                         let parser_snapshot_after_type =
 274                             mem::replace(self, parser_snapshot_before_type);
 275                         Some((parser_snapshot_after_type, colon_sp, err))
 276                     };
 277                     (err, None)
 278                 }
 279             }
 280         } else {
 281             (None, None)
 282         };
 283         let init = match (self.parse_initializer(err.is_some()), err) {
 284             (Ok(init), None) => {
 285                 // init parsed, ty parsed
 286                 init
 287             }
 288             (Ok(init), Some((_, colon_sp, mut err))) => {
 289                 // init parsed, ty error
 290                 // Could parse the type as if it were the initializer, it is likely there was a
 291                 // typo in the code: `:` instead of `=`. Add suggestion and emit the error.
 292                 err.span_suggestion_short(
 293                     colon_sp,
 294                     "use `=` if you meant to assign",
 295                     " =".to_string(),
 296                     Applicability::MachineApplicable,
 297                 );
 298                 err.emit();
 299                 // As this was parsed successfully, continue as if the code has been fixed for the
 300                 // rest of the file. It will still fail due to the emitted error, but we avoid
 301                 // extra noise.
 302                 init
 303             }
 304             (Err(init_err), Some((snapshot, _, ty_err))) => {
 305                 // init error, ty error
 306                 init_err.cancel();
 307                 // Couldn't parse the type nor the initializer, only raise the type error and
 308                 // return to the parser state before parsing the type as the initializer.
 309                 // let x: <parse_error>;
 310                 *self = snapshot;
 311                 return Err(ty_err);
 312             }
 313             (Err(err), None) => {
 314                 // init error, ty parsed
 315                 // Couldn't parse the initializer and we're not attempting to recover a failed
 316                 // parse of the type, return the error.
 317                 return Err(err);
 318             }
 319         };
 320         let kind = match init {
 321             None => LocalKind::Decl,
 322             Some(init) => {
 323                 if self.eat_keyword(kw::Else) {
 324                     if self.token.is_keyword(kw::If) {
 325                         // `let...else if`. Emit the same error that `parse_block()` would,
 326                         // but explicitly point out that this pattern is not allowed.
 327                         let msg = "conditional `else if` is not supported for `let...else`";
 328                         return Err(self.error_block_no_opening_brace_msg(msg));
 329                     }
 330                     let els = self.parse_block()?;
 331                     self.check_let_else_init_bool_expr(&init);
 332                     self.check_let_else_init_trailing_brace(&init);
 333                     LocalKind::InitElse(init, els)
 334                 } else {
 335                     LocalKind::Init(init)
 336                 }
 337             }
 338         };
 339         let hi = if self.token == token::Semi { self.token.span } else { self.prev_token.span };
 340         Ok(P(ast::Local { ty, pat, kind, id: DUMMY_NODE_ID, span: lo.to(hi), attrs, tokens: None }))
 341     }
 342
 343     fn check_let_else_init_bool_expr(&self, init: &ast::Expr) {
 344         if let ast::ExprKind::Binary(op, ..) = init.kind {
 345             if op.node.lazy() {
 346                 let suggs = vec![
 347                     (init.span.shrink_to_lo(), "(".to_string()),
 348                     (init.span.shrink_to_hi(), ")".to_string()),
 349                 ];
 350                 self.struct_span_err(
 351                     init.span,
 352                     &format!(
 353                         "a `{}` expression cannot be directly assigned in `let...else`",
 354                         op.node.to_string()
 355                     ),
 356                 )
 357                 .multipart_suggestion(
 358                     "wrap the expression in parentheses",
 359                     suggs,
 360                     Applicability::MachineApplicable,
 361                 )
 362                 .emit();
 363             }
 364         }
 365     }
 366
 367     fn check_let_else_init_trailing_brace(&self, init: &ast::Expr) {
 368         if let Some(trailing) = classify::expr_trailing_brace(init) {
 369             let err_span = trailing.span.with_lo(trailing.span.hi() - BytePos(1));
 370             let suggs = vec![
 371                 (trailing.span.shrink_to_lo(), "(".to_string()),
 372                 (trailing.span.shrink_to_hi(), ")".to_string()),
 373             ];
 374             self.struct_span_err(
 375                 err_span,
 376                 "right curly brace `}` before `else` in a `let...else` statement not allowed",
 377             )
 378             .multipart_suggestion(
 379                 "try wrapping the expression in parentheses",
 380                 suggs,
 381                 Applicability::MachineApplicable,
 382             )
 383             .emit();
 384         }
 385     }
 386
 387     /// Parses the RHS of a local variable declaration (e.g., `= 14;`).
 388     fn parse_initializer(&mut self, eq_optional: bool) -> PResult<'a, Option<P<Expr>>> {
 389         let eq_consumed = match self.token.kind {
 390             token::BinOpEq(..) => {
 391                 // Recover `let x <op>= 1` as `let x = 1`
 392                 self.struct_span_err(
 393                     self.token.span,
 394                     "can't reassign to an uninitialized variable",
 395                 )
 396                 .span_suggestion_short(
 397                     self.token.span,
 398                     "initialize the variable",
 399                     "=".to_string(),
 400                     Applicability::MaybeIncorrect,
 401                 )
 402                 .help("if you meant to overwrite, remove the `let` binding")
 403                 .emit();
 404                 self.bump();
 405                 true
 406             }
 407             _ => self.eat(&token::Eq),
 408         };
 409
 410         Ok(if eq_consumed || eq_optional { Some(self.parse_expr()?) } else { None })
 411     }
 412
 413     /// Parses a block. No inner attributes are allowed.
 414     pub(super) fn parse_block(&mut self) -> PResult<'a, P<Block>> {
 415         let (attrs, block) = self.parse_inner_attrs_and_block()?;
 416         if let [.., last] = &*attrs {
 417             self.error_on_forbidden_inner_attr(last.span, DEFAULT_INNER_ATTR_FORBIDDEN);
 418         }
 419         Ok(block)
 420     }
 421
 422     fn error_block_no_opening_brace_msg(
 423         &mut self,
 424         msg: &str,
 425     ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
 426         let sp = self.token.span;
 427         let mut e = self.struct_span_err(sp, msg);
 428         let do_not_suggest_help = self.token.is_keyword(kw::In) || self.token == token::Colon;
 429
 430         // Check to see if the user has written something like
 431         //
 432         //    if (cond)
 433         //      bar;
 434         //
 435         // which is valid in other languages, but not Rust.
 436         match self.parse_stmt_without_recovery(false, ForceCollect::No) {
 437             // If the next token is an open brace (e.g., `if a b {`), the place-
 438             // inside-a-block suggestion would be more likely wrong than right.
 439             Ok(Some(_))
 440                 if self.look_ahead(1, |t| t == &token::OpenDelim(Delimiter::Brace))
 441                     || do_not_suggest_help => {}
 442             // Do not suggest `if foo println!("") {;}` (as would be seen in test for #46836).
 443             Ok(Some(Stmt { kind: StmtKind::Empty, .. })) => {}
 444             Ok(Some(stmt)) => {
 445                 let stmt_own_line = self.sess.source_map().is_line_before_span_empty(sp);
 446                 let stmt_span = if stmt_own_line && self.eat(&token::Semi) {
 447                     // Expand the span to include the semicolon.
 448                     stmt.span.with_hi(self.prev_token.span.hi())
 449                 } else {
 450                     stmt.span
 451                 };
 452                 e.multipart_suggestion(
 453                     "try placing this code inside a block",
 454                     vec![
 455                         (stmt_span.shrink_to_lo(), "{ ".to_string()),
 456                         (stmt_span.shrink_to_hi(), " }".to_string()),
 457                     ],
 458                     // Speculative; has been misleading in the past (#46836).
 459                     Applicability::MaybeIncorrect,
 460                 );
 461             }
 462             Err(e) => {
 463                 self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
 464                 e.cancel();
 465             }
 466             _ => {}
 467         }
 468         e.span_label(sp, "expected `{`");
 469         e
 470     }
 471
 472     fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> {
 473         let tok = super::token_descr(&self.token);
 474         let msg = format!("expected `{{`, found {}", tok);
 475         Err(self.error_block_no_opening_brace_msg(&msg))
 476     }
 477
 478     /// Parses a block. Inner attributes are allowed.
 479     pub(super) fn parse_inner_attrs_and_block(
 480         &mut self,
 481     ) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
 482         self.parse_block_common(self.token.span, BlockCheckMode::Default)
 483     }
 484
 485     /// Parses a block. Inner attributes are allowed.
 486     pub(super) fn parse_block_common(
 487         &mut self,
 488         lo: Span,
 489         blk_mode: BlockCheckMode,
 490     ) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
 491         maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
 492
 493         self.maybe_recover_unexpected_block_label();
 494         if !self.eat(&token::OpenDelim(Delimiter::Brace)) {
 495             return self.error_block_no_opening_brace();
 496         }
 497
 498         let attrs = self.parse_inner_attributes()?;
 499         let tail = match self.maybe_suggest_struct_literal(lo, blk_mode) {
 500             Some(tail) => tail?,
 501             None => self.parse_block_tail(lo, blk_mode, AttemptLocalParseRecovery::Yes)?,
 502         };
 503         Ok((attrs, tail))
 504     }
 505
 506     /// Parses the rest of a block expression or function body.
 507     /// Precondition: already parsed the '{'.
 508     crate fn parse_block_tail(
 509         &mut self,
 510         lo: Span,
 511         s: BlockCheckMode,
 512         recover: AttemptLocalParseRecovery,
 513     ) -> PResult<'a, P<Block>> {
 514         let mut stmts = vec![];
 515         while !self.eat(&token::CloseDelim(Delimiter::Brace)) {
 516             if self.token == token::Eof {
 517                 break;
 518             }
 519             let stmt = match self.parse_full_stmt(recover) {
 520                 Err(mut err) if recover.yes() => {
 521                     self.maybe_annotate_with_ascription(&mut err, false);
 522                     err.emit();
 523                     self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
 524                     Some(self.mk_stmt_err(self.token.span))
 525                 }
 526                 Ok(stmt) => stmt,
 527                 Err(err) => return Err(err),
 528             };
 529             if let Some(stmt) = stmt {
 530                 stmts.push(stmt);
 531             } else {
 532                 // Found only `;` or `}`.
 533                 continue;
 534             };
 535         }
 536         Ok(self.mk_block(stmts, s, lo.to(self.prev_token.span)))
 537     }
 538
 539     /// Parses a statement, including the trailing semicolon.
 540     pub fn parse_full_stmt(
 541         &mut self,
 542         recover: AttemptLocalParseRecovery,
 543     ) -> PResult<'a, Option<Stmt>> {
 544         // Skip looking for a trailing semicolon when we have an interpolated statement.
 545         maybe_whole!(self, NtStmt, |x| Some(x.into_inner()));
 546
 547         let Some(mut stmt) = self.parse_stmt_without_recovery(true, ForceCollect::No)? else {
 548             return Ok(None);
 549         };
 550
 551         let mut eat_semi = true;
 552         match stmt.kind {
 553             // Expression without semicolon.
 554             StmtKind::Expr(ref mut expr)
 555                 if self.token != token::Eof && classify::expr_requires_semi_to_be_stmt(expr) =>
 556             {
 557                 // Just check for errors and recover; do not eat semicolon yet.
 558                 if let Err(mut e) =
 559                     self.expect_one_of(&[], &[token::Semi, token::CloseDelim(Delimiter::Brace)])
 560                 {
 561                     if let TokenKind::DocComment(..) = self.token.kind {
 562                         if let Ok(snippet) = self.span_to_snippet(self.token.span) {
 563                             let sp = self.token.span;
 564                             let marker = &snippet[..3];
 565                             let (comment_marker, doc_comment_marker) = marker.split_at(2);
 566
 567                             e.span_suggestion(
 568                                 sp.with_hi(sp.lo() + BytePos(marker.len() as u32)),
 569                                 &format!(
 570                                     "add a space before `{}` to use a regular comment",
 571                                     doc_comment_marker,
 572                                 ),
 573                                 format!("{} {}", comment_marker, doc_comment_marker),
 574                                 Applicability::MaybeIncorrect,
 575                             );
 576                         }
 577                     }
 578                     if let Err(mut e) =
 579                         self.check_mistyped_turbofish_with_multiple_type_params(e, expr)
 580                     {
 581                         if recover.no() {
 582                             return Err(e);
 583                         }
 584                         e.emit();
 585                         self.recover_stmt();
 586                     }
 587                     // Don't complain about type errors in body tail after parse error (#57383).
 588                     let sp = expr.span.to(self.prev_token.span);
 589                     *expr = self.mk_expr_err(sp);
 590                 }
 591             }
 592             StmtKind::Expr(_) | StmtKind::MacCall(_) => {}
 593             StmtKind::Local(ref mut local) if let Err(e) = self.expect_semi() => {
 594                 // We might be at the `,` in `let x = foo<bar, baz>;`. Try to recover.
 595                 match &mut local.kind {
 596                     LocalKind::Init(expr) | LocalKind::InitElse(expr, _) => {
 597                         self.check_mistyped_turbofish_with_multiple_type_params(e, expr)?;
 598                         // We found `foo<bar, baz>`, have we fully recovered?
 599                         self.expect_semi()?;
 600                     }
 601                     LocalKind::Decl => return Err(e),
 602                 }
 603                 eat_semi = false;
 604             }
 605             StmtKind::Empty | StmtKind::Item(_) | StmtKind::Local(_) | StmtKind::Semi(_) => eat_semi = false,
 606         }
 607
 608         if eat_semi && self.eat(&token::Semi) {
 609             stmt = stmt.add_trailing_semicolon();
 610         }
 611         stmt.span = stmt.span.to(self.prev_token.span);
 612         Ok(Some(stmt))
 613     }
 614
 615     pub(super) fn mk_block(&self, stmts: Vec<Stmt>, rules: BlockCheckMode, span: Span) -> P<Block> {
 616         P(Block {
 617             stmts,
 618             id: DUMMY_NODE_ID,
 619             rules,
 620             span,
 621             tokens: None,
 622             could_be_bare_literal: false,
 623         })
 624     }
 625
 626     pub(super) fn mk_stmt(&self, span: Span, kind: StmtKind) -> Stmt {
 627         Stmt { id: DUMMY_NODE_ID, kind, span }
 628     }
 629
 630     pub(super) fn mk_stmt_err(&self, span: Span) -> Stmt {
 631         self.mk_stmt(span, StmtKind::Expr(self.mk_expr_err(span)))
 632     }
 633
 634     pub(super) fn mk_block_err(&self, span: Span) -> P<Block> {
 635         self.mk_block(vec![self.mk_stmt_err(span)], BlockCheckMode::Default, span)
 636     }
 637 }