| use std::borrow::Cow; |
| use std::mem; |
| use std::ops::Bound; |
| |
| use ast::Label; |
| use rustc_ast as ast; |
| use rustc_ast::ptr::P; |
| use rustc_ast::token::{self, Delimiter, InvisibleOrigin, MetaVarKind, TokenKind}; |
| use rustc_ast::util::classify::{self, TrailingBrace}; |
| use rustc_ast::{ |
| AttrStyle, AttrVec, Block, BlockCheckMode, DUMMY_NODE_ID, Expr, ExprKind, HasAttrs, Local, |
| LocalKind, MacCall, MacCallStmt, MacStmtStyle, Recovered, Stmt, StmtKind, |
| }; |
| use rustc_errors::{Applicability, Diag, PResult}; |
| use rustc_span::{BytePos, ErrorGuaranteed, Ident, Span, kw, sym}; |
| use thin_vec::{ThinVec, thin_vec}; |
| |
| use super::attr::InnerAttrForbiddenReason; |
| use super::diagnostics::AttemptLocalParseRecovery; |
| use super::pat::{PatternLocation, RecoverComma}; |
| use super::path::PathStyle; |
| use super::{ |
| AttrWrapper, BlockMode, FnParseMode, ForceCollect, Parser, Restrictions, SemiColonMode, |
| Trailing, UsePreAttrPos, |
| }; |
| use crate::errors::{self, MalformedLoopLabel}; |
| use crate::exp; |
| |
| impl<'a> Parser<'a> { |
| /// Parses a statement. This stops just before trailing semicolons on everything but items. |
| /// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed. |
| /// |
| /// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of |
| /// whether or not we have attributes. |
| // Public for rustfmt usage. |
| pub fn parse_stmt(&mut self, force_collect: ForceCollect) -> PResult<'a, Option<Stmt>> { |
| Ok(self.parse_stmt_without_recovery(false, force_collect, false).unwrap_or_else(|e| { |
| e.emit(); |
| self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore); |
| None |
| })) |
| } |
| |
| /// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of |
| /// whether or not we have attributes. If `force_full_expr` is true, parses the stmt without |
| /// using `Restriction::STMT_EXPR`. Public for `cfg_eval` macro expansion. |
| pub fn parse_stmt_without_recovery( |
| &mut self, |
| capture_semi: bool, |
| force_collect: ForceCollect, |
| force_full_expr: bool, |
| ) -> PResult<'a, Option<Stmt>> { |
| let pre_attr_pos = self.collect_pos(); |
| let attrs = self.parse_outer_attributes()?; |
| let lo = self.token.span; |
| |
| if let Some(stmt) = self.eat_metavar_seq(MetaVarKind::Stmt, |this| { |
| this.parse_stmt_without_recovery(false, ForceCollect::Yes, false) |
| }) { |
| let mut stmt = stmt.expect("an actual statement"); |
| stmt.visit_attrs(|stmt_attrs| { |
| attrs.prepend_to_nt_inner(stmt_attrs); |
| }); |
| return Ok(Some(stmt)); |
| } |
| |
| if self.token.is_keyword(kw::Mut) && self.is_keyword_ahead(1, &[kw::Let]) { |
| self.bump(); |
| let mut_let_span = lo.to(self.token.span); |
| self.dcx().emit_err(errors::InvalidVariableDeclaration { |
| span: mut_let_span, |
| sub: errors::InvalidVariableDeclarationSub::SwitchMutLetOrder(mut_let_span), |
| }); |
| } |
| |
| let stmt = if self.token.is_keyword(kw::Super) && self.is_keyword_ahead(1, &[kw::Let]) { |
| self.collect_tokens(None, attrs, force_collect, |this, attrs| { |
| let super_span = this.token.span; |
| this.expect_keyword(exp!(Super))?; |
| this.expect_keyword(exp!(Let))?; |
| this.psess.gated_spans.gate(sym::super_let, super_span); |
| let local = this.parse_local(Some(super_span), attrs)?; |
| let trailing = Trailing::from(capture_semi && this.token == token::Semi); |
| Ok(( |
| this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)), |
| trailing, |
| UsePreAttrPos::No, |
| )) |
| })? |
| } else if self.token.is_keyword(kw::Let) { |
| self.collect_tokens(None, attrs, force_collect, |this, attrs| { |
| this.expect_keyword(exp!(Let))?; |
| let local = this.parse_local(None, attrs)?; |
| let trailing = Trailing::from(capture_semi && this.token == token::Semi); |
| Ok(( |
| this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)), |
| trailing, |
| UsePreAttrPos::No, |
| )) |
| })? |
| } else if self.is_kw_followed_by_ident(kw::Mut) && self.may_recover() { |
| self.recover_stmt_local_after_let( |
| lo, |
| attrs, |
| errors::InvalidVariableDeclarationSub::MissingLet, |
| force_collect, |
| )? |
| } else if self.is_kw_followed_by_ident(kw::Auto) && self.may_recover() { |
| self.bump(); // `auto` |
| self.recover_stmt_local_after_let( |
| lo, |
| attrs, |
| errors::InvalidVariableDeclarationSub::UseLetNotAuto, |
| force_collect, |
| )? |
| } else if self.is_kw_followed_by_ident(sym::var) && self.may_recover() { |
| self.bump(); // `var` |
| self.recover_stmt_local_after_let( |
| lo, |
| attrs, |
| errors::InvalidVariableDeclarationSub::UseLetNotVar, |
| force_collect, |
| )? |
| } else if self.check_path() |
| && !self.token.is_qpath_start() |
| && !self.is_path_start_item() |
| && !self.is_builtin() |
| { |
| // We have avoided contextual keywords like `union`, items with `crate` visibility, |
| // or `auto trait` items. We aim to parse an arbitrary path `a::b` but not something |
| // that starts like a path (1 token), but it fact not a path. |
| // Also, we avoid stealing syntax from `parse_item_`. |
| // |
| // `UsePreAttrPos::Yes` here means the attribute belongs unconditionally to the |
| // expression, not the statement. (But the statement attributes/tokens are obtained |
| // from the expression anyway, because `Stmt` delegates `HasAttrs`/`HasTokens` to |
| // the things within `StmtKind`.) |
| let stmt = self.collect_tokens( |
| Some(pre_attr_pos), |
| AttrWrapper::empty(), |
| force_collect, |
| |this, _empty_attrs| { |
| Ok((this.parse_stmt_path_start(lo, attrs)?, Trailing::No, UsePreAttrPos::Yes)) |
| }, |
| ); |
| match stmt { |
| Ok(stmt) => stmt, |
| Err(mut err) => { |
| self.suggest_add_missing_let_for_stmt(&mut err); |
| return Err(err); |
| } |
| } |
| } else if let Some(item) = self.parse_item_common( |
| attrs.clone(), // FIXME: unwanted clone of attrs |
| false, |
| true, |
| FnParseMode { req_name: |_| true, req_body: true }, |
| force_collect, |
| )? { |
| self.mk_stmt(lo.to(item.span), StmtKind::Item(P(item))) |
| } else if self.eat(exp!(Semi)) { |
| // Do not attempt to parse an expression if we're done here. |
| self.error_outer_attrs(attrs); |
| self.mk_stmt(lo, StmtKind::Empty) |
| } else if self.token != token::CloseBrace { |
| // Remainder are line-expr stmts. This is similar to the `parse_stmt_path_start` case |
| // above. |
| let restrictions = |
| if force_full_expr { Restrictions::empty() } else { Restrictions::STMT_EXPR }; |
| let e = self.collect_tokens( |
| Some(pre_attr_pos), |
| AttrWrapper::empty(), |
| force_collect, |
| |this, _empty_attrs| { |
| let (expr, _) = this.parse_expr_res(restrictions, attrs)?; |
| Ok((expr, Trailing::No, UsePreAttrPos::Yes)) |
| }, |
| )?; |
| if matches!(e.kind, ExprKind::Assign(..)) && self.eat_keyword(exp!(Else)) { |
| let bl = self.parse_block()?; |
| // Destructuring assignment ... else. |
| // This is not allowed, but point it out in a nice way. |
| self.dcx().emit_err(errors::AssignmentElseNotAllowed { span: e.span.to(bl.span) }); |
| } |
| self.mk_stmt(lo.to(e.span), StmtKind::Expr(e)) |
| } else { |
| self.error_outer_attrs(attrs); |
| return Ok(None); |
| }; |
| |
| self.maybe_augment_stashed_expr_in_pats_with_suggestions(&stmt); |
| Ok(Some(stmt)) |
| } |
| |
| fn parse_stmt_path_start(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> { |
| let stmt = self.collect_tokens(None, attrs, ForceCollect::No, |this, attrs| { |
| let path = this.parse_path(PathStyle::Expr)?; |
| |
| if this.eat(exp!(Bang)) { |
| let stmt_mac = this.parse_stmt_mac(lo, attrs, path)?; |
| return Ok(( |
| stmt_mac, |
| Trailing::from(this.token == token::Semi), |
| UsePreAttrPos::No, |
| )); |
| } |
| |
| let expr = if this.eat(exp!(OpenBrace)) { |
| this.parse_expr_struct(None, path, true)? |
| } else { |
| let hi = this.prev_token.span; |
| this.mk_expr(lo.to(hi), ExprKind::Path(None, path)) |
| }; |
| |
| let expr = this.with_res(Restrictions::STMT_EXPR, |this| { |
| this.parse_expr_dot_or_call_with(attrs, expr, lo) |
| })?; |
| // `DUMMY_SP` will get overwritten later in this function |
| Ok(( |
| this.mk_stmt(rustc_span::DUMMY_SP, StmtKind::Expr(expr)), |
| Trailing::No, |
| UsePreAttrPos::No, |
| )) |
| })?; |
| |
| if let StmtKind::Expr(expr) = stmt.kind { |
| // Perform this outside of the `collect_tokens` closure, since our |
| // outer attributes do not apply to this part of the expression. |
| let (expr, _) = self.with_res(Restrictions::STMT_EXPR, |this| { |
| this.parse_expr_assoc_rest_with(Bound::Unbounded, true, expr) |
| })?; |
| Ok(self.mk_stmt(lo.to(self.prev_token.span), StmtKind::Expr(expr))) |
| } else { |
| Ok(stmt) |
| } |
| } |
| |
| /// Parses a statement macro `mac!(args)` provided a `path` representing `mac`. |
| /// At this point, the `!` token after the path has already been eaten. |
| fn parse_stmt_mac(&mut self, lo: Span, attrs: AttrVec, path: ast::Path) -> PResult<'a, Stmt> { |
| let args = self.parse_delim_args()?; |
| let hi = self.prev_token.span; |
| |
| let style = match args.delim { |
| Delimiter::Brace => MacStmtStyle::Braces, |
| _ => MacStmtStyle::NoBraces, |
| }; |
| |
| let mac = P(MacCall { path, args }); |
| |
| let kind = if (style == MacStmtStyle::Braces |
| && !matches!(self.token.kind, token::Dot | token::Question)) |
| || matches!( |
| self.token.kind, |
| token::Semi |
| | token::Eof |
| | token::CloseInvisible(InvisibleOrigin::MetaVar(MetaVarKind::Stmt)) |
| ) { |
| StmtKind::MacCall(P(MacCallStmt { mac, style, attrs, tokens: None })) |
| } else { |
| // Since none of the above applied, this is an expression statement macro. |
| let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac)); |
| let e = self.maybe_recover_from_bad_qpath(e)?; |
| let e = self.parse_expr_dot_or_call_with(attrs, e, lo)?; |
| let (e, _) = self.parse_expr_assoc_rest_with(Bound::Unbounded, false, e)?; |
| StmtKind::Expr(e) |
| }; |
| Ok(self.mk_stmt(lo.to(hi), kind)) |
| } |
| |
| /// Error on outer attributes in this context. |
| /// Also error if the previous token was a doc comment. |
| fn error_outer_attrs(&self, attrs: AttrWrapper) { |
| if !attrs.is_empty() |
| && let attrs @ [.., last] = &*attrs.take_for_recovery(self.psess) |
| { |
| if last.is_doc_comment() { |
| self.dcx().emit_err(errors::DocCommentDoesNotDocumentAnything { |
| span: last.span, |
| missing_comma: None, |
| }); |
| } else if attrs.iter().any(|a| a.style == AttrStyle::Outer) { |
| self.dcx().emit_err(errors::ExpectedStatementAfterOuterAttr { span: last.span }); |
| } |
| } |
| } |
| |
| fn recover_stmt_local_after_let( |
| &mut self, |
| lo: Span, |
| attrs: AttrWrapper, |
| subdiagnostic: fn(Span) -> errors::InvalidVariableDeclarationSub, |
| force_collect: ForceCollect, |
| ) -> PResult<'a, Stmt> { |
| let stmt = self.collect_tokens(None, attrs, force_collect, |this, attrs| { |
| let local = this.parse_local(None, attrs)?; |
| // FIXME - maybe capture semicolon in recovery? |
| Ok(( |
| this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)), |
| Trailing::No, |
| UsePreAttrPos::No, |
| )) |
| })?; |
| self.dcx() |
| .emit_err(errors::InvalidVariableDeclaration { span: lo, sub: subdiagnostic(lo) }); |
| Ok(stmt) |
| } |
| |
| /// Parses a local variable declaration. |
| fn parse_local(&mut self, super_: Option<Span>, attrs: AttrVec) -> PResult<'a, P<Local>> { |
| let lo = super_.unwrap_or(self.prev_token.span); |
| |
| if self.token.is_keyword(kw::Const) && self.look_ahead(1, |t| t.is_ident()) { |
| self.dcx().emit_err(errors::ConstLetMutuallyExclusive { span: lo.to(self.token.span) }); |
| self.bump(); |
| } |
| |
| let (pat, colon) = |
| self.parse_pat_before_ty(None, RecoverComma::Yes, PatternLocation::LetBinding)?; |
| |
| let (err, ty, colon_sp) = if colon { |
| // Save the state of the parser before parsing type normally, in case there is a `:` |
| // instead of an `=` typo. |
| let parser_snapshot_before_type = self.clone(); |
| let colon_sp = self.prev_token.span; |
| match self.parse_ty() { |
| Ok(ty) => (None, Some(ty), Some(colon_sp)), |
| Err(mut err) => { |
| err.span_label( |
| colon_sp, |
| format!( |
| "while parsing the type for {}", |
| pat.descr() |
| .map_or_else(|| "the binding".to_string(), |n| format!("`{n}`")) |
| ), |
| ); |
| // we use noexpect here because we don't actually expect Eq to be here |
| // but we are still checking for it in order to be able to handle it if |
| // it is there |
| let err = if self.check_noexpect(&token::Eq) { |
| err.emit(); |
| None |
| } else { |
| // Rewind to before attempting to parse the type and continue parsing. |
| let parser_snapshot_after_type = |
| mem::replace(self, parser_snapshot_before_type); |
| Some((parser_snapshot_after_type, colon_sp, err)) |
| }; |
| (err, None, Some(colon_sp)) |
| } |
| } |
| } else { |
| (None, None, None) |
| }; |
| let init = match (self.parse_initializer(err.is_some()), err) { |
| (Ok(init), None) => { |
| // init parsed, ty parsed |
| init |
| } |
| (Ok(init), Some((_, colon_sp, mut err))) => { |
| // init parsed, ty error |
| // Could parse the type as if it were the initializer, it is likely there was a |
| // typo in the code: `:` instead of `=`. Add suggestion and emit the error. |
| err.span_suggestion_short( |
| colon_sp, |
| "use `=` if you meant to assign", |
| " =", |
| Applicability::MachineApplicable, |
| ); |
| err.emit(); |
| // As this was parsed successfully, continue as if the code has been fixed for the |
| // rest of the file. It will still fail due to the emitted error, but we avoid |
| // extra noise. |
| init |
| } |
| (Err(init_err), Some((snapshot, _, ty_err))) => { |
| // init error, ty error |
| init_err.cancel(); |
| // Couldn't parse the type nor the initializer, only raise the type error and |
| // return to the parser state before parsing the type as the initializer. |
| // let x: <parse_error>; |
| *self = snapshot; |
| return Err(ty_err); |
| } |
| (Err(err), None) => { |
| // init error, ty parsed |
| // Couldn't parse the initializer and we're not attempting to recover a failed |
| // parse of the type, return the error. |
| return Err(err); |
| } |
| }; |
| let kind = match init { |
| None => LocalKind::Decl, |
| Some(init) => { |
| if self.eat_keyword(exp!(Else)) { |
| if self.token.is_keyword(kw::If) { |
| // `let...else if`. Emit the same error that `parse_block()` would, |
| // but explicitly point out that this pattern is not allowed. |
| let msg = "conditional `else if` is not supported for `let...else`"; |
| return Err(self.error_block_no_opening_brace_msg(Cow::from(msg))); |
| } |
| let els = self.parse_block()?; |
| self.check_let_else_init_bool_expr(&init); |
| self.check_let_else_init_trailing_brace(&init); |
| LocalKind::InitElse(init, els) |
| } else { |
| LocalKind::Init(init) |
| } |
| } |
| }; |
| let hi = if self.token == token::Semi { self.token.span } else { self.prev_token.span }; |
| Ok(P(ast::Local { |
| super_, |
| ty, |
| pat, |
| kind, |
| id: DUMMY_NODE_ID, |
| span: lo.to(hi), |
| colon_sp, |
| attrs, |
| tokens: None, |
| })) |
| } |
| |
| fn check_let_else_init_bool_expr(&self, init: &ast::Expr) { |
| if let ast::ExprKind::Binary(op, ..) = init.kind { |
| if op.node.is_lazy() { |
| self.dcx().emit_err(errors::InvalidExpressionInLetElse { |
| span: init.span, |
| operator: op.node.as_str(), |
| sugg: errors::WrapInParentheses::Expression { |
| left: init.span.shrink_to_lo(), |
| right: init.span.shrink_to_hi(), |
| }, |
| }); |
| } |
| } |
| } |
| |
| fn check_let_else_init_trailing_brace(&self, init: &ast::Expr) { |
| if let Some(trailing) = classify::expr_trailing_brace(init) { |
| let (span, sugg) = match trailing { |
| TrailingBrace::MacCall(mac) => ( |
| mac.span(), |
| errors::WrapInParentheses::MacroArgs { |
| left: mac.args.dspan.open, |
| right: mac.args.dspan.close, |
| }, |
| ), |
| TrailingBrace::Expr(expr) => ( |
| expr.span, |
| errors::WrapInParentheses::Expression { |
| left: expr.span.shrink_to_lo(), |
| right: expr.span.shrink_to_hi(), |
| }, |
| ), |
| }; |
| self.dcx().emit_err(errors::InvalidCurlyInLetElse { |
| span: span.with_lo(span.hi() - BytePos(1)), |
| sugg, |
| }); |
| } |
| } |
| |
| /// Parses the RHS of a local variable declaration (e.g., `= 14;`). |
| fn parse_initializer(&mut self, eq_optional: bool) -> PResult<'a, Option<P<Expr>>> { |
| let eq_consumed = match self.token.kind { |
| token::PlusEq |
| | token::MinusEq |
| | token::StarEq |
| | token::SlashEq |
| | token::PercentEq |
| | token::CaretEq |
| | token::AndEq |
| | token::OrEq |
| | token::ShlEq |
| | token::ShrEq => { |
| // Recover `let x <op>= 1` as `let x = 1` We must not use `+ BytePos(1)` here |
| // because `<op>` can be a multi-byte lookalike that was recovered, e.g. `âž–=` (the |
| // `âž–` is a U+2796 Heavy Minus Sign Unicode Character) that was recovered as a |
| // `-=`. |
| let extra_op_span = self.psess.source_map().start_point(self.token.span); |
| self.dcx().emit_err(errors::CompoundAssignmentExpressionInLet { |
| span: self.token.span, |
| suggestion: extra_op_span, |
| }); |
| self.bump(); |
| true |
| } |
| _ => self.eat(exp!(Eq)), |
| }; |
| |
| Ok(if eq_consumed || eq_optional { Some(self.parse_expr()?) } else { None }) |
| } |
| |
| /// Parses a block. No inner attributes are allowed. |
| pub fn parse_block(&mut self) -> PResult<'a, P<Block>> { |
| let (attrs, block) = self.parse_inner_attrs_and_block(None)?; |
| if let [.., last] = &*attrs { |
| let suggest_to_outer = match &last.kind { |
| ast::AttrKind::Normal(attr) => attr.item.is_valid_for_outer_style(), |
| _ => false, |
| }; |
| self.error_on_forbidden_inner_attr( |
| last.span, |
| super::attr::InnerAttrPolicy::Forbidden(Some( |
| InnerAttrForbiddenReason::InCodeBlock, |
| )), |
| suggest_to_outer, |
| ); |
| } |
| Ok(block) |
| } |
| |
| fn error_block_no_opening_brace_msg(&mut self, msg: Cow<'static, str>) -> Diag<'a> { |
| let prev = self.prev_token.span; |
| let sp = self.token.span; |
| let mut err = self.dcx().struct_span_err(sp, msg); |
| self.label_expected_raw_ref(&mut err); |
| |
| let do_not_suggest_help = self.token.is_keyword(kw::In) |
| || self.token == token::Colon |
| || self.prev_token.is_keyword(kw::Raw); |
| |
| // Check to see if the user has written something like |
| // |
| // if (cond) |
| // bar; |
| // |
| // which is valid in other languages, but not Rust. |
| match self.parse_stmt_without_recovery(false, ForceCollect::No, false) { |
| // If the next token is an open brace, e.g., we have: |
| // |
| // if expr other_expr { |
| // ^ ^ ^- lookahead(1) is a brace |
| // | |- current token is not "else" |
| // |- (statement we just parsed) |
| // |
| // the place-inside-a-block suggestion would be more likely wrong than right. |
| // |
| // FIXME(compiler-errors): this should probably parse an arbitrary expr and not |
| // just lookahead one token, so we can see if there's a brace after _that_, |
| // since we want to protect against: |
| // `if 1 1 + 1 {` being suggested as `if { 1 } 1 + 1 {` |
| // + + |
| Ok(Some(_)) |
| if (!self.token.is_keyword(kw::Else) |
| && self.look_ahead(1, |t| t == &token::OpenBrace)) |
| || do_not_suggest_help => {} |
| // Do not suggest `if foo println!("") {;}` (as would be seen in test for #46836). |
| Ok(Some(Stmt { kind: StmtKind::Empty, .. })) => {} |
| Ok(Some(stmt)) => { |
| let stmt_own_line = self.psess.source_map().is_line_before_span_empty(sp); |
| let stmt_span = if stmt_own_line && self.eat(exp!(Semi)) { |
| // Expand the span to include the semicolon. |
| stmt.span.with_hi(self.prev_token.span.hi()) |
| } else { |
| stmt.span |
| }; |
| self.suggest_fixes_misparsed_for_loop_head( |
| &mut err, |
| prev.between(sp), |
| stmt_span, |
| &stmt.kind, |
| ); |
| } |
| Err(e) => { |
| e.delay_as_bug(); |
| } |
| _ => {} |
| } |
| err.span_label(sp, "expected `{`"); |
| err |
| } |
| |
| fn suggest_fixes_misparsed_for_loop_head( |
| &self, |
| e: &mut Diag<'_>, |
| between: Span, |
| stmt_span: Span, |
| stmt_kind: &StmtKind, |
| ) { |
| match (&self.token.kind, &stmt_kind) { |
| (token::OpenBrace, StmtKind::Expr(expr)) if let ExprKind::Call(..) = expr.kind => { |
| // for _ in x y() {} |
| e.span_suggestion_verbose( |
| between, |
| "you might have meant to write a method call", |
| ".".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| (token::OpenBrace, StmtKind::Expr(expr)) if let ExprKind::Field(..) = expr.kind => { |
| // for _ in x y.z {} |
| e.span_suggestion_verbose( |
| between, |
| "you might have meant to write a field access", |
| ".".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| (token::CloseBrace, StmtKind::Expr(expr)) |
| if let ExprKind::Struct(expr) = &expr.kind |
| && let None = expr.qself |
| && expr.path.segments.len() == 1 => |
| { |
| // This is specific to "mistyped `if` condition followed by empty body" |
| // |
| // for _ in x y {} |
| e.span_suggestion_verbose( |
| between, |
| "you might have meant to write a field access", |
| ".".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| (token::OpenBrace, StmtKind::Expr(expr)) |
| if let ExprKind::Lit(lit) = expr.kind |
| && let None = lit.suffix |
| && let token::LitKind::Integer | token::LitKind::Float = lit.kind => |
| { |
| // for _ in x 0 {} |
| // for _ in x 0.0 {} |
| e.span_suggestion_verbose( |
| between, |
| format!("you might have meant to write a field access"), |
| ".".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| (token::OpenBrace, StmtKind::Expr(expr)) |
| if let ExprKind::Loop(..) |
| | ExprKind::If(..) |
| | ExprKind::While(..) |
| | ExprKind::Match(..) |
| | ExprKind::ForLoop { .. } |
| | ExprKind::TryBlock(..) |
| | ExprKind::Ret(..) |
| | ExprKind::Closure(..) |
| | ExprKind::Struct(..) |
| | ExprKind::Try(..) = expr.kind => |
| { |
| // These are more likely to have been meant as a block body. |
| e.multipart_suggestion( |
| "you might have meant to write this as part of a block", |
| vec![ |
| (stmt_span.shrink_to_lo(), "{ ".to_string()), |
| (stmt_span.shrink_to_hi(), " }".to_string()), |
| ], |
| // Speculative; has been misleading in the past (#46836). |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| (token::OpenBrace, _) => {} |
| (_, _) => { |
| e.multipart_suggestion( |
| "you might have meant to write this as part of a block", |
| vec![ |
| (stmt_span.shrink_to_lo(), "{ ".to_string()), |
| (stmt_span.shrink_to_hi(), " }".to_string()), |
| ], |
| // Speculative; has been misleading in the past (#46836). |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| |
| fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> { |
| let tok = super::token_descr(&self.token); |
| let msg = format!("expected `{{`, found {tok}"); |
| Err(self.error_block_no_opening_brace_msg(Cow::from(msg))) |
| } |
| |
| /// Parses a block. Inner attributes are allowed, block labels are not. |
| /// |
| /// If `loop_header` is `Some` and an unexpected block label is encountered, |
| /// it is suggested to be moved just before `loop_header`, else it is suggested to be removed. |
| pub(super) fn parse_inner_attrs_and_block( |
| &mut self, |
| loop_header: Option<Span>, |
| ) -> PResult<'a, (AttrVec, P<Block>)> { |
| self.parse_block_common(self.token.span, BlockCheckMode::Default, loop_header) |
| } |
| |
| /// Parses a block. Inner attributes are allowed, block labels are not. |
| /// |
| /// If `loop_header` is `Some` and an unexpected block label is encountered, |
| /// it is suggested to be moved just before `loop_header`, else it is suggested to be removed. |
| pub(super) fn parse_block_common( |
| &mut self, |
| lo: Span, |
| blk_mode: BlockCheckMode, |
| loop_header: Option<Span>, |
| ) -> PResult<'a, (AttrVec, P<Block>)> { |
| if let Some(block) = self.eat_metavar_seq(MetaVarKind::Block, |this| this.parse_block()) { |
| return Ok((AttrVec::new(), block)); |
| } |
| |
| let maybe_ident = self.prev_token; |
| self.maybe_recover_unexpected_block_label(loop_header); |
| if !self.eat(exp!(OpenBrace)) { |
| return self.error_block_no_opening_brace(); |
| } |
| |
| let attrs = self.parse_inner_attributes()?; |
| let tail = match self.maybe_suggest_struct_literal(lo, blk_mode, maybe_ident) { |
| Some(tail) => tail?, |
| None => self.parse_block_tail(lo, blk_mode, AttemptLocalParseRecovery::Yes)?, |
| }; |
| Ok((attrs, tail)) |
| } |
| |
| /// Parses the rest of a block expression or function body. |
| /// Precondition: already parsed the '{'. |
| pub fn parse_block_tail( |
| &mut self, |
| lo: Span, |
| s: BlockCheckMode, |
| recover: AttemptLocalParseRecovery, |
| ) -> PResult<'a, P<Block>> { |
| let mut stmts = ThinVec::new(); |
| let mut snapshot = None; |
| while !self.eat(exp!(CloseBrace)) { |
| if self.token == token::Eof { |
| break; |
| } |
| if self.is_vcs_conflict_marker(&TokenKind::Shl, &TokenKind::Lt) { |
| // Account for `<<<<<<<` diff markers. We can't proactively error here because |
| // that can be a valid path start, so we snapshot and reparse only we've |
| // encountered another parse error. |
| snapshot = Some(self.create_snapshot_for_diagnostic()); |
| } |
| let stmt = match self.parse_full_stmt(recover) { |
| Err(mut err) if recover.yes() => { |
| if let Some(ref mut snapshot) = snapshot { |
| snapshot.recover_vcs_conflict_marker(); |
| } |
| if self.token == token::Colon { |
| // if a previous and next token of the current one is |
| // integer literal (e.g. `1:42`), it's likely a range |
| // expression for Pythonistas and we can suggest so. |
| if self.prev_token.is_integer_lit() |
| && self.may_recover() |
| && self.look_ahead(1, |token| token.is_integer_lit()) |
| { |
| // FIXME(hkmatsumoto): Might be better to trigger |
| // this only when parsing an index expression. |
| err.span_suggestion_verbose( |
| self.token.span, |
| "you might have meant a range expression", |
| "..", |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| // if next token is following a colon, it's likely a path |
| // and we can suggest a path separator |
| self.bump(); |
| if self.token.span.lo() == self.prev_token.span.hi() { |
| err.span_suggestion_verbose( |
| self.prev_token.span, |
| "maybe write a path separator here", |
| "::", |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| |
| let guar = err.emit(); |
| self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore); |
| Some(self.mk_stmt_err(self.token.span, guar)) |
| } |
| Ok(stmt) => stmt, |
| Err(err) => return Err(err), |
| }; |
| if let Some(stmt) = stmt { |
| stmts.push(stmt); |
| } else { |
| // Found only `;` or `}`. |
| continue; |
| }; |
| } |
| Ok(self.mk_block(stmts, s, lo.to(self.prev_token.span))) |
| } |
| |
| fn recover_missing_dot(&mut self, err: &mut Diag<'_>) { |
| let Some((ident, _)) = self.token.ident() else { |
| return; |
| }; |
| if let Some(c) = ident.name.as_str().chars().next() |
| && c.is_uppercase() |
| { |
| return; |
| } |
| if self.token.is_reserved_ident() && !self.token.is_ident_named(kw::Await) { |
| return; |
| } |
| if self.prev_token.is_reserved_ident() && self.prev_token.is_ident_named(kw::Await) { |
| // Likely `foo.await bar` |
| } else if self.prev_token.is_non_reserved_ident() { |
| // Likely `foo bar` |
| } else if self.prev_token.kind == token::Question { |
| // `foo? bar` |
| } else if self.prev_token.kind == token::CloseParen { |
| // `foo() bar` |
| } else { |
| return; |
| } |
| if self.token.span == self.prev_token.span { |
| // Account for syntax errors in proc-macros. |
| return; |
| } |
| if self.look_ahead(1, |t| [token::Semi, token::Question, token::Dot].contains(&t.kind)) { |
| err.span_suggestion_verbose( |
| self.prev_token.span.between(self.token.span), |
| "you might have meant to write a field access", |
| ".".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| if self.look_ahead(1, |t| t.kind == token::OpenParen) { |
| err.span_suggestion_verbose( |
| self.prev_token.span.between(self.token.span), |
| "you might have meant to write a method call", |
| ".".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| |
| /// Parses a statement, including the trailing semicolon. |
| pub fn parse_full_stmt( |
| &mut self, |
| recover: AttemptLocalParseRecovery, |
| ) -> PResult<'a, Option<Stmt>> { |
| // Skip looking for a trailing semicolon when we have a metavar seq. |
| if let Some(stmt) = self.eat_metavar_seq(MetaVarKind::Stmt, |this| { |
| // Why pass `true` for `force_full_expr`? Statement expressions are less expressive |
| // than "full" expressions, due to the `STMT_EXPR` restriction, and sometimes need |
| // parentheses. E.g. the "full" expression `match paren_around_match {} | true` when |
| // used in statement context must be written `(match paren_around_match {} | true)`. |
| // However, if the expression we are parsing in this statement context was pasted by a |
| // declarative macro, it may have come from a "full" expression context, and lack |
| // these parentheses. So we lift the `STMT_EXPR` restriction to ensure the statement |
| // will reparse successfully. |
| this.parse_stmt_without_recovery(false, ForceCollect::No, true) |
| }) { |
| let stmt = stmt.expect("an actual statement"); |
| return Ok(Some(stmt)); |
| } |
| |
| let Some(mut stmt) = self.parse_stmt_without_recovery(true, ForceCollect::No, false)? |
| else { |
| return Ok(None); |
| }; |
| |
| let mut eat_semi = true; |
| let mut add_semi_to_stmt = false; |
| |
| match &mut stmt.kind { |
| // Expression without semicolon. |
| StmtKind::Expr(expr) |
| if classify::expr_requires_semi_to_be_stmt(expr) |
| && !expr.attrs.is_empty() |
| && !matches!(self.token.kind, token::Eof | token::Semi | token::CloseBrace) => |
| { |
| // The user has written `#[attr] expr` which is unsupported. (#106020) |
| let guar = self.attr_on_non_tail_expr(&expr); |
| // We already emitted an error, so don't emit another type error |
| let sp = expr.span.to(self.prev_token.span); |
| *expr = self.mk_expr_err(sp, guar); |
| } |
| |
| // Expression without semicolon. |
| StmtKind::Expr(expr) |
| if self.token != token::Eof && classify::expr_requires_semi_to_be_stmt(expr) => |
| { |
| // Just check for errors and recover; do not eat semicolon yet. |
| |
| let expect_result = |
| if let Err(e) = self.maybe_recover_from_ternary_operator(Some(expr.span)) { |
| Err(e) |
| } else { |
| self.expect_one_of(&[], &[exp!(Semi), exp!(CloseBrace)]) |
| }; |
| |
| // Try to both emit a better diagnostic, and avoid further errors by replacing |
| // the `expr` with `ExprKind::Err`. |
| let replace_with_err = 'break_recover: { |
| match expect_result { |
| Ok(Recovered::No) => None, |
| Ok(Recovered::Yes(guar)) => { |
| // Skip type error to avoid extra errors. |
| Some(guar) |
| } |
| Err(e) => { |
| if self.recover_colon_as_semi() { |
| // recover_colon_as_semi has already emitted a nicer error. |
| e.delay_as_bug(); |
| add_semi_to_stmt = true; |
| eat_semi = false; |
| |
| break 'break_recover None; |
| } |
| |
| match &expr.kind { |
| ExprKind::Path(None, ast::Path { segments, .. }) |
| if let [segment] = segments.as_slice() => |
| { |
| if self.token == token::Colon |
| && self.look_ahead(1, |token| { |
| token.is_metavar_block() |
| || matches!( |
| token.kind, |
| token::Ident( |
| kw::For | kw::Loop | kw::While, |
| token::IdentIsRaw::No |
| ) | token::OpenBrace |
| ) |
| }) |
| { |
| let snapshot = self.create_snapshot_for_diagnostic(); |
| let label = Label { |
| ident: Ident::from_str_and_span( |
| &format!("'{}", segment.ident), |
| segment.ident.span, |
| ), |
| }; |
| match self.parse_expr_labeled(label, false) { |
| Ok(labeled_expr) => { |
| e.cancel(); |
| self.dcx().emit_err(MalformedLoopLabel { |
| span: label.ident.span, |
| suggestion: label.ident.span.shrink_to_lo(), |
| }); |
| *expr = labeled_expr; |
| break 'break_recover None; |
| } |
| Err(err) => { |
| err.cancel(); |
| self.restore_snapshot(snapshot); |
| } |
| } |
| } |
| } |
| _ => {} |
| } |
| |
| let res = |
| self.check_mistyped_turbofish_with_multiple_type_params(e, expr); |
| |
| Some(if recover.no() { |
| res? |
| } else { |
| res.unwrap_or_else(|mut e| { |
| self.recover_missing_dot(&mut e); |
| let guar = e.emit(); |
| self.recover_stmt(); |
| guar |
| }) |
| }) |
| } |
| } |
| }; |
| |
| if let Some(guar) = replace_with_err { |
| // We already emitted an error, so don't emit another type error |
| let sp = expr.span.to(self.prev_token.span); |
| *expr = self.mk_expr_err(sp, guar); |
| } |
| } |
| StmtKind::Expr(_) | StmtKind::MacCall(_) => {} |
| StmtKind::Let(local) if let Err(mut e) = self.expect_semi() => { |
| // We might be at the `,` in `let x = foo<bar, baz>;`. Try to recover. |
| match &mut local.kind { |
| LocalKind::Init(expr) | LocalKind::InitElse(expr, _) => { |
| self.check_mistyped_turbofish_with_multiple_type_params(e, expr).map_err( |
| |mut e| { |
| self.recover_missing_dot(&mut e); |
| e |
| }, |
| )?; |
| // We found `foo<bar, baz>`, have we fully recovered? |
| self.expect_semi()?; |
| } |
| LocalKind::Decl => { |
| if let Some(colon_sp) = local.colon_sp { |
| e.span_label( |
| colon_sp, |
| format!( |
| "while parsing the type for {}", |
| local.pat.descr().map_or_else( |
| || "the binding".to_string(), |
| |n| format!("`{n}`") |
| ) |
| ), |
| ); |
| let suggest_eq = if self.token == token::Dot |
| && let _ = self.bump() |
| && let mut snapshot = self.create_snapshot_for_diagnostic() |
| && let Ok(_) = snapshot |
| .parse_dot_suffix_expr( |
| colon_sp, |
| self.mk_expr_err( |
| colon_sp, |
| self.dcx() |
| .delayed_bug("error during `:` -> `=` recovery"), |
| ), |
| ) |
| .map_err(Diag::cancel) |
| { |
| true |
| } else if let Some(op) = self.check_assoc_op() |
| && op.node.can_continue_expr_unambiguously() |
| { |
| true |
| } else { |
| false |
| }; |
| if suggest_eq { |
| e.span_suggestion_short( |
| colon_sp, |
| "use `=` if you meant to assign", |
| "=", |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| return Err(e); |
| } |
| } |
| eat_semi = false; |
| } |
| StmtKind::Empty | StmtKind::Item(_) | StmtKind::Let(_) | StmtKind::Semi(_) => { |
| eat_semi = false |
| } |
| } |
| |
| if add_semi_to_stmt || (eat_semi && self.eat(exp!(Semi))) { |
| stmt = stmt.add_trailing_semicolon(); |
| } |
| |
| stmt.span = stmt.span.to(self.prev_token.span); |
| Ok(Some(stmt)) |
| } |
| |
| pub(super) fn mk_block( |
| &self, |
| stmts: ThinVec<Stmt>, |
| rules: BlockCheckMode, |
| span: Span, |
| ) -> P<Block> { |
| P(Block { stmts, id: DUMMY_NODE_ID, rules, span, tokens: None }) |
| } |
| |
| pub(super) fn mk_stmt(&self, span: Span, kind: StmtKind) -> Stmt { |
| Stmt { id: DUMMY_NODE_ID, kind, span } |
| } |
| |
| pub(super) fn mk_stmt_err(&self, span: Span, guar: ErrorGuaranteed) -> Stmt { |
| self.mk_stmt(span, StmtKind::Expr(self.mk_expr_err(span, guar))) |
| } |
| |
| pub(super) fn mk_block_err(&self, span: Span, guar: ErrorGuaranteed) -> P<Block> { |
| self.mk_block(thin_vec![self.mk_stmt_err(span, guar)], BlockCheckMode::Default, span) |
| } |
| } |
