diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/expr.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/expr.rs | 418 |
1 files changed, 242 insertions, 176 deletions
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index 11301f03e48..fe7401786a0 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -7,34 +7,30 @@ use super::{ }; use crate::errors::{ ArrayBracketsInsteadOfSpaces, ArrayBracketsInsteadOfSpacesSugg, AsyncMoveOrderIncorrect, - BinaryFloatLiteralNotSupported, BracesForStructLiteral, CatchAfterTry, CommaAfterBaseStruct, - ComparisonInterpretedAsGeneric, ComparisonOrShiftInterpretedAsGenericSugg, - DoCatchSyntaxRemoved, DotDotDot, EqFieldInit, ExpectedElseBlock, ExpectedExpressionFoundLet, + BracesForStructLiteral, CatchAfterTry, CommaAfterBaseStruct, ComparisonInterpretedAsGeneric, + ComparisonOrShiftInterpretedAsGenericSugg, DoCatchSyntaxRemoved, DotDotDot, EqFieldInit, + ExpectedElseBlock, ExpectedEqForLetExpr, ExpectedExpressionFoundLet, FieldExpressionWithGeneric, FloatLiteralRequiresIntegerPart, FoundExprWouldBeStmt, - HexadecimalFloatLiteralNotSupported, IfExpressionMissingCondition, - IfExpressionMissingThenBlock, IfExpressionMissingThenBlockSub, IntLiteralTooLarge, + IfExpressionMissingCondition, IfExpressionMissingThenBlock, IfExpressionMissingThenBlockSub, InvalidBlockMacroSegment, InvalidComparisonOperator, InvalidComparisonOperatorSub, - InvalidFloatLiteralSuffix, InvalidFloatLiteralWidth, InvalidIntLiteralWidth, - InvalidInterpolatedExpression, InvalidLiteralSuffix, InvalidLiteralSuffixOnTupleIndex, - InvalidLogicalOperator, InvalidLogicalOperatorSub, InvalidNumLiteralBasePrefix, - InvalidNumLiteralSuffix, LabeledLoopInBreak, LeadingPlusNotSupported, LeftArrowOperator, + InvalidInterpolatedExpression, InvalidLiteralSuffixOnTupleIndex, InvalidLogicalOperator, + InvalidLogicalOperatorSub, LabeledLoopInBreak, LeadingPlusNotSupported, LeftArrowOperator, LifetimeInBorrowExpression, MacroInvocationWithQualifiedPath, MalformedLoopLabel, MatchArmBodyWithoutBraces, MatchArmBodyWithoutBracesSugg, MissingCommaAfterMatchArm, - MissingInInForLoop, MissingInInForLoopSub, MissingSemicolonBeforeArray, NoFieldsForFnCall, - NotAsNegationOperator, NotAsNegationOperatorSub, OctalFloatLiteralNotSupported, + MissingDotDot, MissingInInForLoop, MissingInInForLoopSub, MissingSemicolonBeforeArray, + NoFieldsForFnCall, NotAsNegationOperator, NotAsNegationOperatorSub, OuterAttributeNotAllowedOnIfElse, ParenthesesWithStructFields, RequireColonAfterLabeledExpression, ShiftInterpretedAsGeneric, StructLiteralNotAllowedHere, - StructLiteralNotAllowedHereSugg, TildeAsUnaryOperator, UnexpectedTokenAfterLabel, - UnexpectedTokenAfterLabelSugg, WrapExpressionInParentheses, + StructLiteralNotAllowedHereSugg, TildeAsUnaryOperator, UnexpectedIfWithIf, + UnexpectedTokenAfterLabel, UnexpectedTokenAfterLabelSugg, WrapExpressionInParentheses, }; use crate::maybe_recover_from_interpolated_ty_qpath; - use core::mem; use rustc_ast::ptr::P; use rustc_ast::token::{self, Delimiter, Token, TokenKind}; use rustc_ast::tokenstream::Spacing; +use rustc_ast::util::case::Case; use rustc_ast::util::classify; -use rustc_ast::util::literal::LitError; use rustc_ast::util::parser::{prec_let_scrutinee_needs_par, AssocOp, Fixity}; use rustc_ast::visit::Visitor; use rustc_ast::{self as ast, AttrStyle, AttrVec, CaptureBy, ExprField, Lit, UnOp, DUMMY_NODE_ID}; @@ -42,9 +38,11 @@ use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty use rustc_ast::{Arm, Async, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits}; use rustc_ast::{ClosureBinder, StmtKind}; use rustc_ast_pretty::pprust; -use rustc_errors::IntoDiagnostic; -use rustc_errors::{Applicability, Diagnostic, PResult}; -use rustc_session::errors::ExprParenthesesNeeded; +use rustc_errors::{ + Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic, PResult, + StashKey, +}; +use rustc_session::errors::{report_lit_error, ExprParenthesesNeeded}; use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP; use rustc_session::lint::BuiltinLintDiagnostics; use rustc_span::source_map::{self, Span, Spanned}; @@ -130,7 +128,7 @@ impl<'a> Parser<'a> { Ok(expr) => Ok(expr), Err(mut err) => match self.token.ident() { Some((Ident { name: kw::Underscore, .. }, false)) - if self.look_ahead(1, |t| t == &token::Comma) => + if self.may_recover() && self.look_ahead(1, |t| t == &token::Comma) => { // Special-case handling of `foo(_, _, _)` err.emit(); @@ -454,7 +452,7 @@ impl<'a> Parser<'a> { return None; } (Some(op), _) => (op, self.token.span), - (None, Some((Ident { name: sym::and, span }, false))) => { + (None, Some((Ident { name: sym::and, span }, false))) if self.may_recover() => { self.sess.emit_err(InvalidLogicalOperator { span: self.token.span, incorrect: "and".into(), @@ -462,7 +460,7 @@ impl<'a> Parser<'a> { }); (AssocOp::LAnd, span) } - (None, Some((Ident { name: sym::or, span }, false))) => { + (None, Some((Ident { name: sym::or, span }, false))) if self.may_recover() => { self.sess.emit_err(InvalidLogicalOperator { span: self.token.span, incorrect: "or".into(), @@ -613,7 +611,7 @@ impl<'a> Parser<'a> { token::Ident(..) if this.token.is_keyword(kw::Box) => { make_it!(this, attrs, |this, _| this.parse_box_expr(lo)) } - token::Ident(..) if this.is_mistaken_not_ident_negation() => { + token::Ident(..) if this.may_recover() && this.is_mistaken_not_ident_negation() => { make_it!(this, attrs, |this, _| this.recover_not_expr(lo)) } _ => return this.parse_dot_or_call_expr(Some(attrs)), @@ -716,6 +714,10 @@ impl<'a> Parser<'a> { let cast_expr = match self.parse_as_cast_ty() { Ok(rhs) => mk_expr(self, lhs, rhs), Err(type_err) => { + if !self.may_recover() { + return Err(type_err); + } + // Rewind to before attempting to parse the type with generics, to recover // from situations like `x as usize < y` in which we first tried to parse // `usize < y` as a type with generic arguments. @@ -827,23 +829,18 @@ impl<'a> Parser<'a> { ("cast", None) }; - // Save the memory location of expr before parsing any following postfix operators. - // This will be compared with the memory location of the output expression. - // If they different we can assume we parsed another expression because the existing expression is not reallocated. - let addr_before = &*cast_expr as *const _ as usize; let with_postfix = self.parse_dot_or_call_expr_with_(cast_expr, span)?; - let changed = addr_before != &*with_postfix as *const _ as usize; // Check if an illegal postfix operator has been added after the cast. - // If the resulting expression is not a cast, or has a different memory location, it is an illegal postfix operator. - if !matches!(with_postfix.kind, ExprKind::Cast(_, _) | ExprKind::Type(_, _)) || changed { + // If the resulting expression is not a cast, it is an illegal postfix operator. + if !matches!(with_postfix.kind, ExprKind::Cast(_, _) | ExprKind::Type(_, _)) { let msg = format!( "{cast_kind} cannot be followed by {}", match with_postfix.kind { ExprKind::Index(_, _) => "indexing", ExprKind::Try(_) => "`?`", ExprKind::Field(_, _) => "a field access", - ExprKind::MethodCall(_, _, _, _) => "a method call", + ExprKind::MethodCall(_) => "a method call", ExprKind::Call(_, _) => "a function call", ExprKind::Await(_) => "`.await`", ExprKind::Err => return Ok(with_postfix), @@ -1195,6 +1192,10 @@ impl<'a> Parser<'a> { seq: &mut PResult<'a, P<Expr>>, snapshot: Option<(SnapshotParser<'a>, ExprKind)>, ) -> Option<P<Expr>> { + if !self.may_recover() { + return None; + } + match (seq.as_mut(), snapshot) { (Err(err), Some((mut snapshot, ExprKind::Path(None, path)))) => { snapshot.bump(); // `(` @@ -1261,24 +1262,32 @@ impl<'a> Parser<'a> { } let fn_span_lo = self.token.span; - let mut segment = self.parse_path_segment(PathStyle::Expr, None)?; - self.check_trailing_angle_brackets(&segment, &[&token::OpenDelim(Delimiter::Parenthesis)]); - self.check_turbofish_missing_angle_brackets(&mut segment); + let mut seg = self.parse_path_segment(PathStyle::Expr, None)?; + self.check_trailing_angle_brackets(&seg, &[&token::OpenDelim(Delimiter::Parenthesis)]); + self.check_turbofish_missing_angle_brackets(&mut seg); if self.check(&token::OpenDelim(Delimiter::Parenthesis)) { // Method call `expr.f()` let args = self.parse_paren_expr_seq()?; let fn_span = fn_span_lo.to(self.prev_token.span); let span = lo.to(self.prev_token.span); - Ok(self.mk_expr(span, ExprKind::MethodCall(segment, self_arg, args, fn_span))) + Ok(self.mk_expr( + span, + ExprKind::MethodCall(Box::new(ast::MethodCall { + seg, + receiver: self_arg, + args, + span: fn_span, + })), + )) } else { // Field access `expr.f` - if let Some(args) = segment.args { + if let Some(args) = seg.args { self.sess.emit_err(FieldExpressionWithGeneric(args.span())); } let span = lo.to(self.prev_token.span); - Ok(self.mk_expr(span, ExprKind::Field(self_arg, segment.ident))) + Ok(self.mk_expr(span, ExprKind::Field(self_arg, seg.ident))) } } @@ -1358,7 +1367,7 @@ impl<'a> Parser<'a> { ) } else if self.check_inline_const(0) { self.parse_const_block(lo.to(self.token.span), false) - } else if self.is_do_catch_block() { + } else if self.may_recover() && self.is_do_catch_block() { self.recover_do_catch() } else if self.is_try_block() { self.expect_keyword(kw::Try)?; @@ -1409,9 +1418,9 @@ impl<'a> Parser<'a> { fn parse_lit_expr(&mut self) -> PResult<'a, P<Expr>> { let lo = self.token.span; - match self.parse_opt_lit() { - Some(literal) => { - let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Lit(literal)); + match self.parse_opt_token_lit() { + Some((token_lit, _)) => { + let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Lit(token_lit)); self.maybe_recover_from_bad_qpath(expr) } None => self.try_macro_suggestion(), @@ -1497,7 +1506,7 @@ impl<'a> Parser<'a> { }); (lo.to(self.prev_token.span), ExprKind::MacCall(mac)) } else if self.check(&token::OpenDelim(Delimiter::Brace)) && - let Some(expr) = self.maybe_parse_struct_expr(qself.as_ref(), &path) { + let Some(expr) = self.maybe_parse_struct_expr(&qself, &path) { if qself.is_some() { self.sess.gated_spans.gate(sym::more_qualified_paths, path.span); } @@ -1513,11 +1522,11 @@ impl<'a> Parser<'a> { /// Parse `'label: $expr`. The label is already parsed. fn parse_labeled_expr( &mut self, - label: Label, + label_: Label, mut consume_colon: bool, ) -> PResult<'a, P<Expr>> { - let lo = label.ident.span; - let label = Some(label); + let lo = label_.ident.span; + let label = Some(label_); let ate_colon = self.eat(&token::Colon); let expr = if self.eat_keyword(kw::While) { self.parse_while_expr(label, lo) @@ -1530,6 +1539,20 @@ impl<'a> Parser<'a> { { self.parse_block_expr(label, lo, BlockCheckMode::Default) } else if !ate_colon + && self.may_recover() + && (matches!(self.token.kind, token::CloseDelim(_) | token::Comma) + || self.token.is_op()) + { + let lit = self.recover_unclosed_char(label_.ident, |self_| { + self_.sess.create_err(UnexpectedTokenAfterLabel { + span: self_.token.span, + remove_label: None, + enclose_in_block: None, + }) + }); + consume_colon = false; + Ok(self.mk_expr(lo, ExprKind::Lit(lit.token_lit))) + } else if !ate_colon && (self.check_noexpect(&TokenKind::Comma) || self.check_noexpect(&TokenKind::Gt)) { // We're probably inside of a `Path<'a>` that needs a turbofish @@ -1603,6 +1626,40 @@ impl<'a> Parser<'a> { Ok(expr) } + /// Emit an error when a char is parsed as a lifetime because of a missing quote + pub(super) fn recover_unclosed_char( + &self, + lifetime: Ident, + err: impl FnOnce(&Self) -> DiagnosticBuilder<'a, ErrorGuaranteed>, + ) -> ast::Lit { + if let Some(mut diag) = + self.sess.span_diagnostic.steal_diagnostic(lifetime.span, StashKey::LifetimeIsChar) + { + diag.span_suggestion_verbose( + lifetime.span.shrink_to_hi(), + "add `'` to close the char literal", + "'", + Applicability::MaybeIncorrect, + ) + .emit(); + } else { + err(self) + .span_suggestion_verbose( + lifetime.span.shrink_to_hi(), + "add `'` to close the char literal", + "'", + Applicability::MaybeIncorrect, + ) + .emit(); + } + let name = lifetime.without_first_quote().name; + ast::Lit { + token_lit: token::Lit::new(token::LitKind::Char, name, None), + kind: ast::LitKind::Char(name.as_str().chars().next().unwrap_or('_')), + span: lifetime.span, + } + } + /// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead. fn recover_do_catch(&mut self) -> PResult<'a, P<Expr>> { let lo = self.token.span; @@ -1712,7 +1769,7 @@ impl<'a> Parser<'a> { /// In case of error returns `Some(lit)` if the next token is a literal with a wrong kind, /// and returns `None` if the next token is not literal at all. pub fn parse_str_lit(&mut self) -> Result<ast::StrLit, Option<Lit>> { - match self.parse_opt_lit() { + match self.parse_opt_ast_lit() { Some(lit) => match lit.kind { ast::LitKind::Str(symbol_unescaped, style) => Ok(ast::StrLit { style, @@ -1727,31 +1784,47 @@ impl<'a> Parser<'a> { } } - pub(super) fn parse_lit(&mut self) -> PResult<'a, Lit> { - self.parse_opt_lit().ok_or_else(|| { - if let token::Interpolated(inner) = &self.token.kind { - let expr = match inner.as_ref() { - token::NtExpr(expr) => Some(expr), - token::NtLiteral(expr) => Some(expr), - _ => None, - }; - if let Some(expr) = expr { - if matches!(expr.kind, ExprKind::Err) { - let mut err = InvalidInterpolatedExpression { span: self.token.span } - .into_diagnostic(&self.sess.span_diagnostic); - err.downgrade_to_delayed_bug(); - return err; - } + fn handle_missing_lit(&mut self) -> PResult<'a, Lit> { + if let token::Interpolated(inner) = &self.token.kind { + let expr = match inner.as_ref() { + token::NtExpr(expr) => Some(expr), + token::NtLiteral(expr) => Some(expr), + _ => None, + }; + if let Some(expr) = expr { + if matches!(expr.kind, ExprKind::Err) { + let mut err = InvalidInterpolatedExpression { span: self.token.span } + .into_diagnostic(&self.sess.span_diagnostic); + err.downgrade_to_delayed_bug(); + return Err(err); } } - let msg = format!("unexpected token: {}", super::token_descr(&self.token)); - self.struct_span_err(self.token.span, &msg) - }) + } + let token = self.token.clone(); + let err = |self_: &Self| { + let msg = format!("unexpected token: {}", super::token_descr(&token)); + self_.struct_span_err(token.span, &msg) + }; + // On an error path, eagerly consider a lifetime to be an unclosed character lit + if self.token.is_lifetime() { + let lt = self.expect_lifetime(); + Ok(self.recover_unclosed_char(lt.ident, err)) + } else { + Err(err(self)) + } } - /// Matches `lit = true | false | token_lit`. - /// Returns `None` if the next token is not a literal. - pub(super) fn parse_opt_lit(&mut self) -> Option<Lit> { + pub(super) fn parse_token_lit(&mut self) -> PResult<'a, (token::Lit, Span)> { + self.parse_opt_token_lit() + .ok_or(()) + .or_else(|()| self.handle_missing_lit().map(|lit| (lit.token_lit, lit.span))) + } + + pub(super) fn parse_ast_lit(&mut self) -> PResult<'a, Lit> { + self.parse_opt_ast_lit().ok_or(()).or_else(|()| self.handle_missing_lit()) + } + + fn recover_after_dot(&mut self) -> Option<Token> { let mut recovered = None; if self.token == token::Dot { // Attempt to recover `.4` as `0.4`. We don't currently have any syntax where @@ -1777,100 +1850,50 @@ impl<'a> Parser<'a> { } } - let token = recovered.as_ref().unwrap_or(&self.token); - match Lit::from_token(token) { - Ok(lit) => { - self.bump(); - Some(lit) - } - Err(LitError::NotLiteral) => None, - Err(err) => { - let span = token.span; - let token::Literal(lit) = token.kind else { - unreachable!(); - }; - self.bump(); - self.report_lit_error(err, lit, span); - // Pack possible quotes and prefixes from the original literal into - // the error literal's symbol so they can be pretty-printed faithfully. - let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None); - let symbol = Symbol::intern(&suffixless_lit.to_string()); - let lit = token::Lit::new(token::Err, symbol, lit.suffix); - Some(Lit::from_token_lit(lit, span).unwrap_or_else(|_| unreachable!())) - } - } + recovered } - fn report_lit_error(&self, err: LitError, lit: token::Lit, span: Span) { - // Checks if `s` looks like i32 or u1234 etc. - fn looks_like_width_suffix(first_chars: &[char], s: &str) -> bool { - s.len() > 1 && s.starts_with(first_chars) && s[1..].chars().all(|c| c.is_ascii_digit()) - } - - // Try to lowercase the prefix if it's a valid base prefix. - fn fix_base_capitalisation(s: &str) -> Option<String> { - if let Some(stripped) = s.strip_prefix('B') { - Some(format!("0b{stripped}")) - } else if let Some(stripped) = s.strip_prefix('O') { - Some(format!("0o{stripped}")) - } else if let Some(stripped) = s.strip_prefix('X') { - Some(format!("0x{stripped}")) - } else { - None - } - } + /// Matches `lit = true | false | token_lit`. + /// Returns `None` if the next token is not a literal. + pub(super) fn parse_opt_token_lit(&mut self) -> Option<(token::Lit, Span)> { + let recovered = self.recover_after_dot(); + let token = recovered.as_ref().unwrap_or(&self.token); + let span = token.span; + token::Lit::from_token(token).map(|token_lit| { + self.bump(); + (token_lit, span) + }) + } - let token::Lit { kind, suffix, .. } = lit; - match err { - // `NotLiteral` is not an error by itself, so we don't report - // it and give the parser opportunity to try something else. - LitError::NotLiteral => {} - // `LexerError` *is* an error, but it was already reported - // by lexer, so here we don't report it the second time. - LitError::LexerError => {} - LitError::InvalidSuffix => { - if let Some(suffix) = suffix { - self.sess.emit_err(InvalidLiteralSuffix { - span, - kind: format!("{}", kind.descr()), - suffix, - }); - } - } - LitError::InvalidIntSuffix => { - let suf = suffix.expect("suffix error with no suffix"); - let suf = suf.as_str(); - if looks_like_width_suffix(&['i', 'u'], &suf) { - // If it looks like a width, try to be helpful. - self.sess.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() }); - } else if let Some(fixed) = fix_base_capitalisation(suf) { - self.sess.emit_err(InvalidNumLiteralBasePrefix { span, fixed }); - } else { - self.sess.emit_err(InvalidNumLiteralSuffix { span, suffix: suf.to_string() }); - } - } - LitError::InvalidFloatSuffix => { - let suf = suffix.expect("suffix error with no suffix"); - let suf = suf.as_str(); - if looks_like_width_suffix(&['f'], suf) { - // If it looks like a width, try to be helpful. - self.sess - .emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() }); - } else { - self.sess.emit_err(InvalidFloatLiteralSuffix { span, suffix: suf.to_string() }); + /// Matches `lit = true | false | token_lit`. + /// Returns `None` if the next token is not a literal. + pub(super) fn parse_opt_ast_lit(&mut self) -> Option<Lit> { + let recovered = self.recover_after_dot(); + let token = recovered.as_ref().unwrap_or(&self.token); + match token::Lit::from_token(token) { + Some(token_lit) => { + match Lit::from_token_lit(token_lit, token.span) { + Ok(lit) => { + self.bump(); + Some(lit) + } + Err(err) => { + let span = token.span; + let token::Literal(lit) = token.kind else { + unreachable!(); + }; + self.bump(); + report_lit_error(&self.sess, err, lit, span); + // Pack possible quotes and prefixes from the original literal into + // the error literal's symbol so they can be pretty-printed faithfully. + let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None); + let symbol = Symbol::intern(&suffixless_lit.to_string()); + let lit = token::Lit::new(token::Err, symbol, lit.suffix); + Some(Lit::from_token_lit(lit, span).unwrap_or_else(|_| unreachable!())) + } } } - LitError::NonDecimalFloat(base) => { - match base { - 16 => self.sess.emit_err(HexadecimalFloatLiteralNotSupported { span }), - 8 => self.sess.emit_err(OctalFloatLiteralNotSupported { span }), - 2 => self.sess.emit_err(BinaryFloatLiteralNotSupported { span }), - _ => unreachable!(), - }; - } - LitError::IntTooLarge => { - self.sess.emit_err(IntLiteralTooLarge { span }); - } + None => None, } } @@ -1895,8 +1918,8 @@ impl<'a> Parser<'a> { let lo = self.token.span; let minus_present = self.eat(&token::BinOp(token::Minus)); - let lit = self.parse_lit()?; - let expr = self.mk_expr(lit.span, ExprKind::Lit(lit)); + let (token_lit, span) = self.parse_token_lit()?; + let expr = self.mk_expr(span, ExprKind::Lit(token_lit)); if minus_present { Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_unary(UnOp::Neg, expr))) @@ -1941,6 +1964,10 @@ impl<'a> Parser<'a> { prev_span: Span, open_delim_span: Span, ) -> PResult<'a, ()> { + if !self.may_recover() { + return Ok(()); + } + if self.token.kind == token::Comma { if !self.sess.source_map().is_multiline(prev_span.until(self.token.span)) { return Ok(()); @@ -1981,7 +2008,7 @@ impl<'a> Parser<'a> { lo: Span, blk_mode: BlockCheckMode, ) -> PResult<'a, P<Expr>> { - if self.is_array_like_block() { + if self.may_recover() && self.is_array_like_block() { if let Some(arr) = self.maybe_suggest_brackets_instead_of_braces(lo) { return Ok(arr); } @@ -2024,15 +2051,15 @@ impl<'a> Parser<'a> { if self.eat_keyword(kw::Static) { Movability::Static } else { Movability::Movable }; let asyncness = if self.token.uninterpolated_span().rust_2018() { - self.parse_asyncness() + self.parse_asyncness(Case::Sensitive) } else { Async::No }; let capture_clause = self.parse_capture_clause()?; - let decl = self.parse_fn_block_decl()?; + let fn_decl = self.parse_fn_block_decl()?; let decl_hi = self.prev_token.span; - let mut body = match decl.output { + let mut body = match fn_decl.output { FnRetTy::Default(_) => { let restrictions = self.restrictions - Restrictions::STMT_EXPR; self.parse_expr_res(restrictions, None)? @@ -2051,6 +2078,7 @@ impl<'a> Parser<'a> { if self.token.kind == TokenKind::Semi && matches!(self.token_cursor.frame.delim_sp, Some((Delimiter::Parenthesis, _))) + && self.may_recover() { // It is likely that the closure body is a block but where the // braces have been removed. We will recover and eat the next @@ -2062,15 +2090,15 @@ impl<'a> Parser<'a> { let closure = self.mk_expr( lo.to(body.span), - ExprKind::Closure( + ExprKind::Closure(Box::new(ast::Closure { binder, capture_clause, asyncness, movability, - decl, + fn_decl, body, - lo.to(decl_hi), - ), + fn_decl_span: lo.to(decl_hi), + })), ); // Disable recovery for closure body @@ -2172,7 +2200,7 @@ impl<'a> Parser<'a> { }, ExprKind::Block(_, None) => { self.sess.emit_err(IfExpressionMissingCondition { - if_span: self.sess.source_map().next_point(lo), + if_span: lo.shrink_to_hi(), block_span: self.sess.source_map().start_point(cond_span), }); std::mem::replace(&mut cond, this.mk_expr_err(cond_span.shrink_to_hi())) @@ -2199,13 +2227,14 @@ impl<'a> Parser<'a> { self.mk_block_err(cond_span.shrink_to_hi()) } } else { - let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery. + let attrs = self.parse_outer_attributes()?; // For recovery. let block = if self.check(&token::OpenDelim(Delimiter::Brace)) { self.parse_block()? } else { if let Some(block) = recover_block_from_condition(self) { block } else { + self.error_on_extra_if(&cond)?; // Parse block, which will always fail, but we can add a nice note to the error self.parse_block().map_err(|mut err| { err.span_note( @@ -2216,7 +2245,7 @@ impl<'a> Parser<'a> { })? } }; - self.error_on_if_block_attrs(lo, false, block.span, &attrs); + self.error_on_if_block_attrs(lo, false, block.span, attrs); block }; let els = if self.eat_keyword(kw::Else) { Some(self.parse_else_expr()?) } else { None }; @@ -2257,7 +2286,15 @@ impl<'a> Parser<'a> { RecoverColon::Yes, CommaRecoveryMode::LikelyTuple, )?; - self.expect(&token::Eq)?; + if self.token == token::EqEq { + self.sess.emit_err(ExpectedEqForLetExpr { + span: self.token.span, + sugg_span: self.token.span, + }); + self.bump(); + } else { + self.expect(&token::Eq)?; + } let expr = self.with_res(self.restrictions | Restrictions::NO_STRUCT_LITERAL, |this| { this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into()) })?; @@ -2269,7 +2306,7 @@ impl<'a> Parser<'a> { /// Parses an `else { ... }` expression (`else` token already eaten). fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> { let else_span = self.prev_token.span; // `else` - let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery. + let attrs = self.parse_outer_attributes()?; // For recovery. let expr = if self.eat_keyword(kw::If) { self.parse_if_expr()? } else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) { @@ -2304,7 +2341,7 @@ impl<'a> Parser<'a> { }, } }; - self.error_on_if_block_attrs(else_span, true, expr.span, &attrs); + self.error_on_if_block_attrs(else_span, true, expr.span, attrs); Ok(expr) } @@ -2313,8 +2350,13 @@ impl<'a> Parser<'a> { ctx_span: Span, is_ctx_else: bool, branch_span: Span, - attrs: &[ast::Attribute], + attrs: AttrWrapper, ) { + if attrs.is_empty() { + return; + } + + let attrs: &[ast::Attribute] = &attrs.take_for_recovery(self.sess); let (attributes, last) = match attrs { [] => return, [x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span), @@ -2329,6 +2371,16 @@ impl<'a> Parser<'a> { }); } + fn error_on_extra_if(&mut self, cond: &P<Expr>) -> PResult<'a, ()> { + if let ExprKind::Binary(Spanned { span: binop_span, node: binop}, _, right) = &cond.kind && + let BinOpKind::And = binop && + let ExprKind::If(cond, ..) = &right.kind { + Err(self.sess.create_err(UnexpectedIfWithIf(binop_span.shrink_to_hi().to(cond.span.shrink_to_lo())))) + } else { + Ok(()) + } + } + /// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten). fn parse_for_expr(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> { // Record whether we are about to parse `for (`. @@ -2762,7 +2814,7 @@ impl<'a> Parser<'a> { fn maybe_parse_struct_expr( &mut self, - qself: Option<&ast::QSelf>, + qself: &Option<P<ast::QSelf>>, path: &ast::Path, ) -> Option<PResult<'a, P<Expr>>> { let struct_allowed = !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL); @@ -2770,7 +2822,7 @@ impl<'a> Parser<'a> { if let Err(err) = self.expect(&token::OpenDelim(Delimiter::Brace)) { return Some(Err(err)); } - let expr = self.parse_struct_expr(qself.cloned(), path.clone(), true); + let expr = self.parse_struct_expr(qself.clone(), path.clone(), true); if let (Ok(expr), false) = (&expr, struct_allowed) { // This is a struct literal, but we don't can't accept them here. self.sess.emit_err(StructLiteralNotAllowedHere { @@ -2803,7 +2855,7 @@ impl<'a> Parser<'a> { }; while self.token != token::CloseDelim(close_delim) { - if self.eat(&token::DotDot) { + if self.eat(&token::DotDot) || self.recover_struct_field_dots(close_delim) { let exp_span = self.prev_token.span; // We permit `.. }` on the left-hand side of a destructuring assignment. if self.check(&token::CloseDelim(close_delim)) { @@ -2901,7 +2953,7 @@ impl<'a> Parser<'a> { /// Precondition: already parsed the '{'. pub(super) fn parse_struct_expr( &mut self, - qself: Option<ast::QSelf>, + qself: Option<P<ast::QSelf>>, pth: ast::Path, recover: bool, ) -> PResult<'a, P<Expr>> { @@ -2950,6 +3002,18 @@ impl<'a> Parser<'a> { self.recover_stmt(); } + fn recover_struct_field_dots(&mut self, close_delim: Delimiter) -> bool { + if !self.look_ahead(1, |t| *t == token::CloseDelim(close_delim)) + && self.eat(&token::DotDotDot) + { + // recover from typo of `...`, suggest `..` + let span = self.prev_token.span; + self.sess.emit_err(MissingDotDot { token_span: span, sugg_span: span }); + return true; + } + false + } + /// Parses `ident (COLON expr)?`. fn parse_expr_field(&mut self) -> PResult<'a, ExprField> { let attrs = self.parse_outer_attributes()?; @@ -3080,6 +3144,8 @@ impl<'a> Parser<'a> { && this.token.kind == token::Semi { TrailingToken::Semi + } else if this.token.kind == token::Gt { + TrailingToken::Gt } else { // FIXME - pass this through from the place where we know // we need a comma, rather than assuming that `#[attr] expr,` |