compiler/rustc_parse/src/parser/stmt.rs

   1 use super::attr::InnerAttrForbiddenReason;
   2 use super::diagnostics::AttemptLocalParseRecovery;
   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::errors::{
  11     AssignmentElseNotAllowed, CompoundAssignmentExpressionInLet, ConstLetMutuallyExclusive,
  12     DocCommentDoesNotDocumentAnything, ExpectedStatementAfterOuterAttr, InvalidCurlyInLetElse,
  13     InvalidExpressionInLetElse, InvalidIdentiferStartsWithNumber, InvalidVariableDeclaration,
  14     InvalidVariableDeclarationSub, WrapExpressionInParentheses,
  15 };
  16 use crate::maybe_whole;
  17
  18 use rustc_ast as ast;
  19 use rustc_ast::ptr::P;
  20 use rustc_ast::token::{self, Delimiter, TokenKind};
  21 use rustc_ast::util::classify;
  22 use rustc_ast::{AttrStyle, AttrVec, LocalKind, MacCall, MacCallStmt, MacStmtStyle};
  23 use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, HasAttrs, Local, Stmt};
  24 use rustc_ast::{StmtKind, DUMMY_NODE_ID};
  25 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
  26 use rustc_span::source_map::{BytePos, Span};
  27 use rustc_span::symbol::{kw, sym};
  28
  29 use std::mem;
  30
  31 impl<'a> Parser<'a> {
  32     /// Parses a statement. This stops just before trailing semicolons on everything but items.
  33     /// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
  34     // Public for rustfmt usage.
  35     pub fn parse_stmt(&mut self, force_collect: ForceCollect) -> PResult<'a, Option<Stmt>> {
  36         Ok(self.parse_stmt_without_recovery(false, force_collect).unwrap_or_else(|mut e| {
  37             e.emit();
  38             self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
  39             None
  40         }))
  41     }
  42
  43     /// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of whether
  44     /// or not we have attributes
  45     pub(crate) fn parse_stmt_without_recovery(
  46         &mut self,
  47         capture_semi: bool,
  48         force_collect: ForceCollect,
  49     ) -> PResult<'a, Option<Stmt>> {
  50         let attrs = self.parse_outer_attributes()?;
  51         let lo = self.token.span;
  52
  53         // Don't use `maybe_whole` so that we have precise control
  54         // over when we bump the parser
  55         if let token::Interpolated(nt) = &self.token.kind && let token::NtStmt(stmt) = &**nt {
  56             let mut stmt = stmt.clone();
  57             self.bump();
  58             stmt.visit_attrs(|stmt_attrs| {
  59                 attrs.prepend_to_nt_inner(stmt_attrs);
  60             });
  61             return Ok(Some(stmt.into_inner()));
  62         }
  63
  64         if self.token.is_keyword(kw::Mut) && self.is_keyword_ahead(1, &[kw::Let]) {
  65             self.bump();
  66             let mut_let_span = lo.to(self.token.span);
  67             self.sess.emit_err(InvalidVariableDeclaration {
  68                 span: mut_let_span,
  69                 sub: InvalidVariableDeclarationSub::SwitchMutLetOrder(mut_let_span),
  70             });
  71         }
  72
  73         Ok(Some(if self.token.is_keyword(kw::Let) {
  74             self.parse_local_mk(lo, attrs, capture_semi, force_collect)?
  75         } else if self.is_kw_followed_by_ident(kw::Mut) {
  76             self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::MissingLet)?
  77         } else if self.is_kw_followed_by_ident(kw::Auto) {
  78             self.bump(); // `auto`
  79             self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::UseLetNotAuto)?
  80         } else if self.is_kw_followed_by_ident(sym::var) {
  81             self.bump(); // `var`
  82             self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::UseLetNotVar)?
  83         } else if self.check_path() && !self.token.is_qpath_start() && !self.is_path_start_item() {
  84             // We have avoided contextual keywords like `union`, items with `crate` visibility,
  85             // or `auto trait` items. We aim to parse an arbitrary path `a::b` but not something
  86             // that starts like a path (1 token), but it fact not a path.
  87             // Also, we avoid stealing syntax from `parse_item_`.
  88             if force_collect == ForceCollect::Yes {
  89                 self.collect_tokens_no_attrs(|this| this.parse_stmt_path_start(lo, attrs))
  90             } else {
  91                 self.parse_stmt_path_start(lo, attrs)
  92             }?
  93         } else if let Some(item) = self.parse_item_common(
  94             attrs.clone(),
  95             false,
  96             true,
  97             FnParseMode { req_name: |_| true, req_body: true },
  98             force_collect,
  99         )? {
 100             // FIXME: Bad copy of attrs
 101             self.mk_stmt(lo.to(item.span), StmtKind::Item(P(item)))
 102         } else if self.eat(&token::Semi) {
 103             // Do not attempt to parse an expression if we're done here.
 104             self.error_outer_attrs(attrs);
 105             self.mk_stmt(lo, StmtKind::Empty)
 106         } else if self.token != token::CloseDelim(Delimiter::Brace) {
 107             // Remainder are line-expr stmts.
 108             let e = if force_collect == ForceCollect::Yes {
 109                 self.collect_tokens_no_attrs(|this| {
 110                     this.parse_expr_res(Restrictions::STMT_EXPR, Some(attrs))
 111                 })
 112             } else {
 113                 self.parse_expr_res(Restrictions::STMT_EXPR, Some(attrs))
 114             }?;
 115             if matches!(e.kind, ExprKind::Assign(..)) && self.eat_keyword(kw::Else) {
 116                 let bl = self.parse_block()?;
 117                 // Destructuring assignment ... else.
 118                 // This is not allowed, but point it out in a nice way.
 119                 self.sess.emit_err(AssignmentElseNotAllowed { span: e.span.to(bl.span) });
 120             }
 121             self.mk_stmt(lo.to(e.span), StmtKind::Expr(e))
 122         } else {
 123             self.error_outer_attrs(attrs);
 124             return Ok(None);
 125         }))
 126     }
 127
 128     fn parse_stmt_path_start(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> {
 129         let stmt = self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
 130             let path = this.parse_path(PathStyle::Expr)?;
 131
 132             if this.eat(&token::Not) {
 133                 let stmt_mac = this.parse_stmt_mac(lo, attrs, path)?;
 134                 if this.token == token::Semi {
 135                     return Ok((stmt_mac, TrailingToken::Semi));
 136                 } else {
 137                     return Ok((stmt_mac, TrailingToken::None));
 138                 }
 139             }
 140
 141             let expr = if this.eat(&token::OpenDelim(Delimiter::Brace)) {
 142                 this.parse_struct_expr(None, path, true)?
 143             } else {
 144                 let hi = this.prev_token.span;
 145                 this.mk_expr(lo.to(hi), ExprKind::Path(None, path))
 146             };
 147
 148             let expr = this.with_res(Restrictions::STMT_EXPR, |this| {
 149                 this.parse_dot_or_call_expr_with(expr, lo, attrs)
 150             })?;
 151             // `DUMMY_SP` will get overwritten later in this function
 152             Ok((this.mk_stmt(rustc_span::DUMMY_SP, StmtKind::Expr(expr)), TrailingToken::None))
 153         })?;
 154
 155         if let StmtKind::Expr(expr) = stmt.kind {
 156             // Perform this outside of the `collect_tokens_trailing_token` closure,
 157             // since our outer attributes do not apply to this part of the expression
 158             let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
 159                 this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
 160             })?;
 161             Ok(self.mk_stmt(lo.to(self.prev_token.span), StmtKind::Expr(expr)))
 162         } else {
 163             Ok(stmt)
 164         }
 165     }
 166
 167     /// Parses a statement macro `mac!(args)` provided a `path` representing `mac`.
 168     /// At this point, the `!` token after the path has already been eaten.
 169     fn parse_stmt_mac(&mut self, lo: Span, attrs: AttrVec, path: ast::Path) -> PResult<'a, Stmt> {
 170         let args = self.parse_delim_args()?;
 171         let delim = args.delim.to_token();
 172         let hi = self.prev_token.span;
 173
 174         let style = match delim {
 175             Delimiter::Brace => MacStmtStyle::Braces,
 176             _ => MacStmtStyle::NoBraces,
 177         };
 178
 179         let mac = P(MacCall { path, args, prior_type_ascription: self.last_type_ascription });
 180
 181         let kind = if (style == MacStmtStyle::Braces
 182             && self.token != token::Dot
 183             && self.token != token::Question)
 184             || self.token == token::Semi
 185             || self.token == token::Eof
 186         {
 187             StmtKind::MacCall(P(MacCallStmt { mac, style, attrs, tokens: None }))
 188         } else {
 189             // Since none of the above applied, this is an expression statement macro.
 190             let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac));
 191             let e = self.maybe_recover_from_bad_qpath(e)?;
 192             let e = self.parse_dot_or_call_expr_with(e, lo, attrs)?;
 193             let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
 194             StmtKind::Expr(e)
 195         };
 196         Ok(self.mk_stmt(lo.to(hi), kind))
 197     }
 198
 199     /// Error on outer attributes in this context.
 200     /// Also error if the previous token was a doc comment.
 201     fn error_outer_attrs(&self, attrs: AttrWrapper) {
 202         if !attrs.is_empty()
 203         && let attrs = attrs.take_for_recovery(self.sess)
 204         && let attrs @ [.., last] = &*attrs {
 205             if last.is_doc_comment() {
 206                 self.sess.emit_err(DocCommentDoesNotDocumentAnything {
 207                     span: last.span,
 208                     missing_comma: None,
 209                 });
 210             } else if attrs.iter().any(|a| a.style == AttrStyle::Outer) {
 211                 self.sess.emit_err(ExpectedStatementAfterOuterAttr { span: last.span });
 212             }
 213         }
 214     }
 215
 216     fn recover_stmt_local(
 217         &mut self,
 218         lo: Span,
 219         attrs: AttrWrapper,
 220         subdiagnostic: fn(Span) -> InvalidVariableDeclarationSub,
 221     ) -> PResult<'a, Stmt> {
 222         let stmt = self.recover_local_after_let(lo, attrs)?;
 223         self.sess.emit_err(InvalidVariableDeclaration { span: lo, sub: subdiagnostic(lo) });
 224         Ok(stmt)
 225     }
 226
 227     fn parse_local_mk(
 228         &mut self,
 229         lo: Span,
 230         attrs: AttrWrapper,
 231         capture_semi: bool,
 232         force_collect: ForceCollect,
 233     ) -> PResult<'a, Stmt> {
 234         self.collect_tokens_trailing_token(attrs, force_collect, |this, attrs| {
 235             this.expect_keyword(kw::Let)?;
 236             let local = this.parse_local(attrs)?;
 237             let trailing = if capture_semi && this.token.kind == token::Semi {
 238                 TrailingToken::Semi
 239             } else {
 240                 TrailingToken::None
 241             };
 242             Ok((this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Local(local)), trailing))
 243         })
 244     }
 245
 246     fn recover_local_after_let(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> {
 247         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
 248             let local = this.parse_local(attrs)?;
 249             // FIXME - maybe capture semicolon in recovery?
 250             Ok((
 251                 this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Local(local)),
 252                 TrailingToken::None,
 253             ))
 254         })
 255     }
 256
 257     /// Parses a local variable declaration.
 258     fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P<Local>> {
 259         let lo = self.prev_token.span;
 260
 261         if self.token.is_keyword(kw::Const) && self.look_ahead(1, |t| t.is_ident()) {
 262             self.sess.emit_err(ConstLetMutuallyExclusive { span: lo.to(self.token.span) });
 263             self.bump();
 264         }
 265
 266         self.report_invalid_identifier_error()?;
 267         let (pat, colon) = self.parse_pat_before_ty(None, RecoverComma::Yes, "`let` bindings")?;
 268
 269         let (err, ty) = if colon {
 270             // Save the state of the parser before parsing type normally, in case there is a `:`
 271             // instead of an `=` typo.
 272             let parser_snapshot_before_type = self.clone();
 273             let colon_sp = self.prev_token.span;
 274             match self.parse_ty() {
 275                 Ok(ty) => (None, Some(ty)),
 276                 Err(mut err) => {
 277                     if let Ok(snip) = self.span_to_snippet(pat.span) {
 278                         err.span_label(pat.span, format!("while parsing the type for `{}`", snip));
 279                     }
 280                     // we use noexpect here because we don't actually expect Eq to be here
 281                     // but we are still checking for it in order to be able to handle it if
 282                     // it is there
 283                     let err = if self.check_noexpect(&token::Eq) {
 284                         err.emit();
 285                         None
 286                     } else {
 287                         // Rewind to before attempting to parse the type and continue parsing.
 288                         let parser_snapshot_after_type =
 289                             mem::replace(self, parser_snapshot_before_type);
 290                         Some((parser_snapshot_after_type, colon_sp, err))
 291                     };
 292                     (err, None)
 293                 }
 294             }
 295         } else {
 296             (None, None)
 297         };
 298         let init = match (self.parse_initializer(err.is_some()), err) {
 299             (Ok(init), None) => {
 300                 // init parsed, ty parsed
 301                 init
 302             }
 303             (Ok(init), Some((_, colon_sp, mut err))) => {
 304                 // init parsed, ty error
 305                 // Could parse the type as if it were the initializer, it is likely there was a
 306                 // typo in the code: `:` instead of `=`. Add suggestion and emit the error.
 307                 err.span_suggestion_short(
 308                     colon_sp,
 309                     "use `=` if you meant to assign",
 310                     " =",
 311                     Applicability::MachineApplicable,
 312                 );
 313                 err.emit();
 314                 // As this was parsed successfully, continue as if the code has been fixed for the
 315                 // rest of the file. It will still fail due to the emitted error, but we avoid
 316                 // extra noise.
 317                 init
 318             }
 319             (Err(init_err), Some((snapshot, _, ty_err))) => {
 320                 // init error, ty error
 321                 init_err.cancel();
 322                 // Couldn't parse the type nor the initializer, only raise the type error and
 323                 // return to the parser state before parsing the type as the initializer.
 324                 // let x: <parse_error>;
 325                 *self = snapshot;
 326                 return Err(ty_err);
 327             }
 328             (Err(err), None) => {
 329                 // init error, ty parsed
 330                 // Couldn't parse the initializer and we're not attempting to recover a failed
 331                 // parse of the type, return the error.
 332                 return Err(err);
 333             }
 334         };
 335         let kind = match init {
 336             None => LocalKind::Decl,
 337             Some(init) => {
 338                 if self.eat_keyword(kw::Else) {
 339                     if self.token.is_keyword(kw::If) {
 340                         // `let...else if`. Emit the same error that `parse_block()` would,
 341                         // but explicitly point out that this pattern is not allowed.
 342                         let msg = "conditional `else if` is not supported for `let...else`";
 343                         return Err(self.error_block_no_opening_brace_msg(msg));
 344                     }
 345                     let els = self.parse_block()?;
 346                     self.check_let_else_init_bool_expr(&init);
 347                     self.check_let_else_init_trailing_brace(&init);
 348                     LocalKind::InitElse(init, els)
 349                 } else {
 350                     LocalKind::Init(init)
 351                 }
 352             }
 353         };
 354         let hi = if self.token == token::Semi { self.token.span } else { self.prev_token.span };
 355         Ok(P(ast::Local { ty, pat, kind, id: DUMMY_NODE_ID, span: lo.to(hi), attrs, tokens: None }))
 356     }
 357
 358     /// report error for `let 1x = 123`
 359     pub fn report_invalid_identifier_error(&mut self) -> PResult<'a, ()> {
 360         if let token::Literal(lit) = self.token.uninterpolate().kind &&
 361             rustc_ast::MetaItemLit::from_token(&self.token).is_none() &&
 362             (lit.kind == token::LitKind::Integer || lit.kind == token::LitKind::Float) &&
 363             self.look_ahead(1, |t| matches!(t.kind, token::Eq) || matches!(t.kind, token::Colon ) ) {
 364                 return Err(self.sess.create_err(InvalidIdentiferStartsWithNumber { span: self.token.span }));
 365         }
 366         Ok(())
 367     }
 368
 369     fn check_let_else_init_bool_expr(&self, init: &ast::Expr) {
 370         if let ast::ExprKind::Binary(op, ..) = init.kind {
 371             if op.node.lazy() {
 372                 self.sess.emit_err(InvalidExpressionInLetElse {
 373                     span: init.span,
 374                     operator: op.node.to_string(),
 375                     sugg: WrapExpressionInParentheses {
 376                         left: init.span.shrink_to_lo(),
 377                         right: init.span.shrink_to_hi(),
 378                     },
 379                 });
 380             }
 381         }
 382     }
 383
 384     fn check_let_else_init_trailing_brace(&self, init: &ast::Expr) {
 385         if let Some(trailing) = classify::expr_trailing_brace(init) {
 386             self.sess.emit_err(InvalidCurlyInLetElse {
 387                 span: trailing.span.with_lo(trailing.span.hi() - BytePos(1)),
 388                 sugg: WrapExpressionInParentheses {
 389                     left: trailing.span.shrink_to_lo(),
 390                     right: trailing.span.shrink_to_hi(),
 391                 },
 392             });
 393         }
 394     }
 395
 396     /// Parses the RHS of a local variable declaration (e.g., `= 14;`).
 397     fn parse_initializer(&mut self, eq_optional: bool) -> PResult<'a, Option<P<Expr>>> {
 398         let eq_consumed = match self.token.kind {
 399             token::BinOpEq(..) => {
 400                 // Recover `let x <op>= 1` as `let x = 1`
 401                 self.sess.emit_err(CompoundAssignmentExpressionInLet { span: self.token.span });
 402                 self.bump();
 403                 true
 404             }
 405             _ => self.eat(&token::Eq),
 406         };
 407
 408         Ok(if eq_consumed || eq_optional { Some(self.parse_expr()?) } else { None })
 409     }
 410
 411     /// Parses a block. No inner attributes are allowed.
 412     pub(super) fn parse_block(&mut self) -> PResult<'a, P<Block>> {
 413         let (attrs, block) = self.parse_inner_attrs_and_block()?;
 414         if let [.., last] = &*attrs {
 415             self.error_on_forbidden_inner_attr(
 416                 last.span,
 417                 super::attr::InnerAttrPolicy::Forbidden(Some(
 418                     InnerAttrForbiddenReason::InCodeBlock,
 419                 )),
 420             );
 421         }
 422         Ok(block)
 423     }
 424
 425     fn error_block_no_opening_brace_msg(
 426         &mut self,
 427         msg: &str,
 428     ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
 429         let sp = self.token.span;
 430         let mut e = self.struct_span_err(sp, msg);
 431         let do_not_suggest_help = self.token.is_keyword(kw::In) || self.token == token::Colon;
 432
 433         // Check to see if the user has written something like
 434         //
 435         //    if (cond)
 436         //      bar;
 437         //
 438         // which is valid in other languages, but not Rust.
 439         match self.parse_stmt_without_recovery(false, ForceCollect::No) {
 440             // If the next token is an open brace, e.g., we have:
 441             //
 442             //     if expr other_expr {
 443             //        ^    ^          ^- lookahead(1) is a brace
 444             //        |    |- current token is not "else"
 445             //        |- (statement we just parsed)
 446             //
 447             // the place-inside-a-block suggestion would be more likely wrong than right.
 448             //
 449             // FIXME(compiler-errors): this should probably parse an arbitrary expr and not
 450             // just lookahead one token, so we can see if there's a brace after _that_,
 451             // since we want to protect against:
 452             //     `if 1 1 + 1 {` being suggested as  `if { 1 } 1 + 1 {`
 453             //                                            +   +
 454             Ok(Some(_))
 455                 if (!self.token.is_keyword(kw::Else)
 456                     && self.look_ahead(1, |t| t == &token::OpenDelim(Delimiter::Brace)))
 457                     || do_not_suggest_help => {}
 458             // Do not suggest `if foo println!("") {;}` (as would be seen in test for #46836).
 459             Ok(Some(Stmt { kind: StmtKind::Empty, .. })) => {}
 460             Ok(Some(stmt)) => {
 461                 let stmt_own_line = self.sess.source_map().is_line_before_span_empty(sp);
 462                 let stmt_span = if stmt_own_line && self.eat(&token::Semi) {
 463                     // Expand the span to include the semicolon.
 464                     stmt.span.with_hi(self.prev_token.span.hi())
 465                 } else {
 466                     stmt.span
 467                 };
 468                 e.multipart_suggestion(
 469                     "try placing this code inside a block",
 470                     vec![
 471                         (stmt_span.shrink_to_lo(), "{ ".to_string()),
 472                         (stmt_span.shrink_to_hi(), " }".to_string()),
 473                     ],
 474                     // Speculative; has been misleading in the past (#46836).
 475                     Applicability::MaybeIncorrect,
 476                 );
 477             }
 478             Err(e) => {
 479                 self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
 480                 e.cancel();
 481             }
 482             _ => {}
 483         }
 484         e.span_label(sp, "expected `{`");
 485         e
 486     }
 487
 488     fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> {
 489         let tok = super::token_descr(&self.token);
 490         let msg = format!("expected `{{`, found {}", tok);
 491         Err(self.error_block_no_opening_brace_msg(&msg))
 492     }
 493
 494     /// Parses a block. Inner attributes are allowed.
 495     pub(super) fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (AttrVec, P<Block>)> {
 496         self.parse_block_common(self.token.span, BlockCheckMode::Default)
 497     }
 498
 499     /// Parses a block. Inner attributes are allowed.
 500     pub(super) fn parse_block_common(
 501         &mut self,
 502         lo: Span,
 503         blk_mode: BlockCheckMode,
 504     ) -> PResult<'a, (AttrVec, P<Block>)> {
 505         maybe_whole!(self, NtBlock, |x| (AttrVec::new(), x));
 506
 507         self.maybe_recover_unexpected_block_label();
 508         if !self.eat(&token::OpenDelim(Delimiter::Brace)) {
 509             return self.error_block_no_opening_brace();
 510         }
 511
 512         let attrs = self.parse_inner_attributes()?;
 513         let tail = match self.maybe_suggest_struct_literal(lo, blk_mode) {
 514             Some(tail) => tail?,
 515             None => self.parse_block_tail(lo, blk_mode, AttemptLocalParseRecovery::Yes)?,
 516         };
 517         Ok((attrs, tail))
 518     }
 519
 520     /// Parses the rest of a block expression or function body.
 521     /// Precondition: already parsed the '{'.
 522     pub(crate) fn parse_block_tail(
 523         &mut self,
 524         lo: Span,
 525         s: BlockCheckMode,
 526         recover: AttemptLocalParseRecovery,
 527     ) -> PResult<'a, P<Block>> {
 528         let mut stmts = vec![];
 529         while !self.eat(&token::CloseDelim(Delimiter::Brace)) {
 530             if self.token == token::Eof {
 531                 break;
 532             }
 533             let stmt = match self.parse_full_stmt(recover) {
 534                 Err(mut err) if recover.yes() => {
 535                     self.maybe_annotate_with_ascription(&mut err, false);
 536                     err.emit();
 537                     self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
 538                     Some(self.mk_stmt_err(self.token.span))
 539                 }
 540                 Ok(stmt) => stmt,
 541                 Err(err) => return Err(err),
 542             };
 543             if let Some(stmt) = stmt {
 544                 stmts.push(stmt);
 545             } else {
 546                 // Found only `;` or `}`.
 547                 continue;
 548             };
 549         }
 550         Ok(self.mk_block(stmts, s, lo.to(self.prev_token.span)))
 551     }
 552
 553     /// Parses a statement, including the trailing semicolon.
 554     pub fn parse_full_stmt(
 555         &mut self,
 556         recover: AttemptLocalParseRecovery,
 557     ) -> PResult<'a, Option<Stmt>> {
 558         // Skip looking for a trailing semicolon when we have an interpolated statement.
 559         maybe_whole!(self, NtStmt, |x| Some(x.into_inner()));
 560
 561         let Some(mut stmt) = self.parse_stmt_without_recovery(true, ForceCollect::No)? else {
 562             return Ok(None);
 563         };
 564
 565         let mut eat_semi = true;
 566         match &mut stmt.kind {
 567             // Expression without semicolon.
 568             StmtKind::Expr(expr)
 569                 if self.token != token::Eof && classify::expr_requires_semi_to_be_stmt(expr) => {
 570                 // Just check for errors and recover; do not eat semicolon yet.
 571                 // `expect_one_of` returns PResult<'a, bool /* recovered */>
 572                 let replace_with_err =
 573                     match self.expect_one_of(&[], &[token::Semi, token::CloseDelim(Delimiter::Brace)]) {
 574                     // Recover from parser, skip type error to avoid extra errors.
 575                     Ok(true) => true,
 576                     Err(mut e) => {
 577                         if let TokenKind::DocComment(..) = self.token.kind &&
 578                             let Ok(snippet) = self.span_to_snippet(self.token.span) {
 579                                 let sp = self.token.span;
 580                                 let marker = &snippet[..3];
 581                                 let (comment_marker, doc_comment_marker) = marker.split_at(2);
 582
 583                                 e.span_suggestion(
 584                                     sp.with_hi(sp.lo() + BytePos(marker.len() as u32)),
 585                                     &format!(
 586                                         "add a space before `{}` to use a regular comment",
 587                                         doc_comment_marker,
 588                                     ),
 589                                     format!("{} {}", comment_marker, doc_comment_marker),
 590                                     Applicability::MaybeIncorrect,
 591                                 );
 592                         }
 593
 594                         if let Err(mut e) =
 595                             self.check_mistyped_turbofish_with_multiple_type_params(e, expr)
 596                         {
 597                             if recover.no() {
 598                                 return Err(e);
 599                             }
 600                             e.emit();
 601                             self.recover_stmt();
 602                         }
 603                         true
 604                     }
 605                     _ => false
 606                 };
 607                 if replace_with_err {
 608                     // We already emitted an error, so don't emit another type error
 609                     let sp = expr.span.to(self.prev_token.span);
 610                     *expr = self.mk_expr_err(sp);
 611                 }
 612             }
 613             StmtKind::Expr(_) | StmtKind::MacCall(_) => {}
 614             StmtKind::Local(local) if let Err(e) = self.expect_semi() => {
 615                 // We might be at the `,` in `let x = foo<bar, baz>;`. Try to recover.
 616                 match &mut local.kind {
 617                     LocalKind::Init(expr) | LocalKind::InitElse(expr, _) => {
 618                         self.check_mistyped_turbofish_with_multiple_type_params(e, expr)?;
 619                         // We found `foo<bar, baz>`, have we fully recovered?
 620                         self.expect_semi()?;
 621                     }
 622                     LocalKind::Decl => return Err(e),
 623                 }
 624                 eat_semi = false;
 625             }
 626             StmtKind::Empty | StmtKind::Item(_) | StmtKind::Local(_) | StmtKind::Semi(_) => eat_semi = false,
 627         }
 628
 629         if eat_semi && self.eat(&token::Semi) {
 630             stmt = stmt.add_trailing_semicolon();
 631         }
 632         stmt.span = stmt.span.to(self.prev_token.span);
 633         Ok(Some(stmt))
 634     }
 635
 636     pub(super) fn mk_block(&self, stmts: Vec<Stmt>, rules: BlockCheckMode, span: Span) -> P<Block> {
 637         P(Block {
 638             stmts,
 639             id: DUMMY_NODE_ID,
 640             rules,
 641             span,
 642             tokens: None,
 643             could_be_bare_literal: false,
 644         })
 645     }
 646
 647     pub(super) fn mk_stmt(&self, span: Span, kind: StmtKind) -> Stmt {
 648         Stmt { id: DUMMY_NODE_ID, kind, span }
 649     }
 650
 651     pub(super) fn mk_stmt_err(&self, span: Span) -> Stmt {
 652         self.mk_stmt(span, StmtKind::Expr(self.mk_expr_err(span)))
 653     }
 654
 655     pub(super) fn mk_block_err(&self, span: Span) -> P<Block> {
 656         self.mk_block(vec![self.mk_stmt_err(span)], BlockCheckMode::Default, span)
 657     }
 658 }