diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/pat.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/pat.rs | 382 |
1 files changed, 168 insertions, 214 deletions
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs index e73a17ced..8e920f1c4 100644 --- a/compiler/rustc_parse/src/parser/pat.rs +++ b/compiler/rustc_parse/src/parser/pat.rs @@ -1,5 +1,14 @@ use super::{ForceCollect, Parser, PathStyle, TrailingToken}; -use crate::errors::RemoveLet; +use crate::errors::{ + AmbiguousRangePattern, DotDotDotForRemainingFields, DotDotDotRangeToPatternNotAllowed, + DotDotDotRestPattern, EnumPatternInsteadOfIdentifier, ExpectedBindingLeftOfAt, + ExpectedCommaAfterPatternField, InclusiveRangeExtraEquals, InclusiveRangeMatchArrow, + InclusiveRangeNoEnd, InvalidMutInPattern, PatternOnWrongSideOfAt, RefMutOrderIncorrect, + RemoveLet, RepeatedMutInPattern, TopLevelOrPatternNotAllowed, TopLevelOrPatternNotAllowedSugg, + TrailingVertNotAllowed, UnexpectedLifetimeInPattern, UnexpectedVertVertBeforeFunctionParam, + UnexpectedVertVertInPattern, +}; +use crate::fluent_generated as fluent; use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole}; use rustc_ast::mut_visit::{noop_visit_pat, MutVisitor}; use rustc_ast::ptr::P; @@ -9,15 +18,32 @@ use rustc_ast::{ PatField, PatKind, Path, QSelf, RangeEnd, RangeSyntax, }; use rustc_ast_pretty::pprust; -use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult}; +use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic, PResult}; use rustc_session::errors::ExprParenthesesNeeded; use rustc_span::source_map::{respan, Span, Spanned}; use rustc_span::symbol::{kw, sym, Ident}; +use thin_vec::{thin_vec, ThinVec}; -pub(super) type Expected = Option<&'static str>; +#[derive(PartialEq, Copy, Clone)] +pub enum Expected { + ParameterName, + ArgumentName, + Identifier, + BindingPattern, +} -/// `Expected` for function and lambda parameter patterns. -pub(super) const PARAM_EXPECTED: Expected = Some("parameter name"); +impl Expected { + // FIXME(#100717): migrate users of this to proper localization + fn to_string_or_fallback(expected: Option<Expected>) -> &'static str { + match expected { + Some(Expected::ParameterName) => "parameter name", + Some(Expected::ArgumentName) => "argument name", + Some(Expected::Identifier) => "identifier", + Some(Expected::BindingPattern) => "binding pattern", + None => "pattern", + } + } +} const WHILE_PARSING_OR_MSG: &str = "while parsing this or-pattern starting here"; @@ -54,13 +80,19 @@ enum EatOrResult { None, } +/// The syntax location of a given pattern. Used for diagnostics. +pub(super) enum PatternLocation { + LetBinding, + FunctionParameter, +} + impl<'a> Parser<'a> { /// Parses a pattern. /// /// Corresponds to `pat<no_top_alt>` in RFC 2535 and does not admit or-patterns /// at the top level. Used when parsing the parameters of lambda expressions, /// functions, function pointers, and `pat` macro fragments. - pub fn parse_pat_no_top_alt(&mut self, expected: Expected) -> PResult<'a, P<Pat>> { + pub fn parse_pat_no_top_alt(&mut self, expected: Option<Expected>) -> PResult<'a, P<Pat>> { self.parse_pat_with_range_pat(true, expected) } @@ -74,7 +106,7 @@ impl<'a> Parser<'a> { /// simplify the grammar somewhat. pub fn parse_pat_allow_top_alt( &mut self, - expected: Expected, + expected: Option<Expected>, rc: RecoverComma, ra: RecoverColon, rt: CommaRecoveryMode, @@ -86,7 +118,7 @@ impl<'a> Parser<'a> { /// recovered). fn parse_pat_allow_top_alt_inner( &mut self, - expected: Expected, + expected: Option<Expected>, rc: RecoverComma, ra: RecoverColon, rt: CommaRecoveryMode, @@ -123,7 +155,7 @@ impl<'a> Parser<'a> { // If there was a leading vert, treat this as an or-pattern. This improves // diagnostics. let span = leading_vert_span.to(self.prev_token.span); - return Ok((self.mk_pat(span, PatKind::Or(vec![first_pat])), trailing_vert)); + return Ok((self.mk_pat(span, PatKind::Or(thin_vec![first_pat])), trailing_vert)); } return Ok((first_pat, trailing_vert)); @@ -131,7 +163,7 @@ impl<'a> Parser<'a> { // Parse the patterns `p_1 | ... | p_n` where `n > 0`. let lo = leading_vert_span.unwrap_or(first_pat.span); - let mut pats = vec![first_pat]; + let mut pats = thin_vec![first_pat]; loop { match self.eat_or_separator(Some(lo)) { EatOrResult::AteOr => {} @@ -165,9 +197,9 @@ impl<'a> Parser<'a> { /// otherwise). pub(super) fn parse_pat_before_ty( &mut self, - expected: Expected, + expected: Option<Expected>, rc: RecoverComma, - syntax_loc: &str, + syntax_loc: PatternLocation, ) -> PResult<'a, (P<Pat>, bool)> { // We use `parse_pat_allow_top_alt` regardless of whether we actually want top-level // or-patterns so that we can detect when a user tries to use it. This allows us to print a @@ -181,27 +213,41 @@ impl<'a> Parser<'a> { let colon = self.eat(&token::Colon); if let PatKind::Or(pats) = &pat.kind { - let msg = format!("top-level or-patterns are not allowed in {}", syntax_loc); - let (help, fix) = if pats.len() == 1 { - // If all we have is a leading vert, then print a special message. This is the case - // if `parse_pat_allow_top_alt` returns an or-pattern with one variant. - let msg = "remove the `|`"; - let fix = pprust::pat_to_string(&pat); - (msg, fix) - } else { - let msg = "wrap the pattern in parentheses"; - let fix = format!("({})", pprust::pat_to_string(&pat)); - (msg, fix) - }; + let span = pat.span; if trailing_vert { // We already emitted an error and suggestion to remove the trailing vert. Don't // emit again. - self.sess.span_diagnostic.delay_span_bug(pat.span, &msg); + + // FIXME(#100717): pass `TopLevelOrPatternNotAllowed::* { sub: None }` to + // `delay_span_bug()` instead of fluent message + self.sess.span_diagnostic.delay_span_bug( + span, + match syntax_loc { + PatternLocation::LetBinding => { + fluent::parse_or_pattern_not_allowed_in_let_binding + } + PatternLocation::FunctionParameter => { + fluent::parse_or_pattern_not_allowed_in_fn_parameters + } + }, + ); } else { - self.struct_span_err(pat.span, &msg) - .span_suggestion(pat.span, help, fix, Applicability::MachineApplicable) - .emit(); + let pat = pprust::pat_to_string(&pat); + let sub = if pats.len() == 1 { + Some(TopLevelOrPatternNotAllowedSugg::RemoveLeadingVert { span, pat }) + } else { + Some(TopLevelOrPatternNotAllowedSugg::WrapInParens { span, pat }) + }; + + self.sess.emit_err(match syntax_loc { + PatternLocation::LetBinding => { + TopLevelOrPatternNotAllowed::LetBinding { span, sub } + } + PatternLocation::FunctionParameter => { + TopLevelOrPatternNotAllowed::FunctionParameter { span, sub } + } + }); } } @@ -218,15 +264,15 @@ impl<'a> Parser<'a> { // a leading `||` probably doesn't indicate an or-pattern attempt, so we handle that // separately. if let token::OrOr = self.token.kind { - let span = self.token.span; - let mut err = self.struct_span_err(span, "unexpected `||` before function parameter"); - err.span_suggestion(span, "remove the `||`", "", Applicability::MachineApplicable); - err.note("alternatives in or-patterns are separated with `|`, not `||`"); - err.emit(); + self.sess.emit_err(UnexpectedVertVertBeforeFunctionParam { span: self.token.span }); self.bump(); } - self.parse_pat_before_ty(PARAM_EXPECTED, RecoverComma::No, "function parameters") + self.parse_pat_before_ty( + Some(Expected::ParameterName), + RecoverComma::No, + PatternLocation::FunctionParameter, + ) } /// Eat the or-pattern `|` separator. @@ -236,7 +282,7 @@ impl<'a> Parser<'a> { EatOrResult::TrailingVert } else if matches!(self.token.kind, token::OrOr) { // Found `||`; Recover and pretend we parsed `|`. - self.ban_unexpected_or_or(lo); + self.sess.emit_err(UnexpectedVertVertInPattern { span: self.token.span, start: lo }); self.bump(); EatOrResult::AteOr } else if self.eat(&token::BinOp(token::Or)) { @@ -270,7 +316,13 @@ impl<'a> Parser<'a> { }); match (is_end_ahead, &self.token.kind) { (true, token::BinOp(token::Or) | token::OrOr) => { - self.ban_illegal_vert(lo, "trailing", "not allowed in an or-pattern"); + // A `|` or possibly `||` token shouldn't be here. Ban it. + self.sess.emit_err(TrailingVertNotAllowed { + span: self.token.span, + start: lo, + token: self.token.clone(), + note_double_vert: matches!(self.token.kind, token::OrOr).then_some(()), + }); self.bump(); true } @@ -278,46 +330,12 @@ impl<'a> Parser<'a> { } } - /// We have parsed `||` instead of `|`. Error and suggest `|` instead. - fn ban_unexpected_or_or(&mut self, lo: Option<Span>) { - let mut err = self.struct_span_err(self.token.span, "unexpected token `||` in pattern"); - err.span_suggestion( - self.token.span, - "use a single `|` to separate multiple alternative patterns", - "|", - Applicability::MachineApplicable, - ); - if let Some(lo) = lo { - err.span_label(lo, WHILE_PARSING_OR_MSG); - } - err.emit(); - } - - /// A `|` or possibly `||` token shouldn't be here. Ban it. - fn ban_illegal_vert(&mut self, lo: Option<Span>, pos: &str, ctx: &str) { - let span = self.token.span; - let mut err = self.struct_span_err(span, &format!("a {} `|` is {}", pos, ctx)); - err.span_suggestion( - span, - &format!("remove the `{}`", pprust::token_to_string(&self.token)), - "", - Applicability::MachineApplicable, - ); - if let Some(lo) = lo { - err.span_label(lo, WHILE_PARSING_OR_MSG); - } - if let token::OrOr = self.token.kind { - err.note("alternatives in or-patterns are separated with `|`, not `||`"); - } - err.emit(); - } - /// Parses a pattern, with a setting whether modern range patterns (e.g., `a..=b`, `a..b` are /// allowed). fn parse_pat_with_range_pat( &mut self, allow_range_pat: bool, - expected: Expected, + expected: Option<Expected>, ) -> PResult<'a, P<Pat>> { maybe_recover_from_interpolated_ty_qpath!(self, true); maybe_whole!(self, NtPat, |x| x); @@ -413,7 +431,7 @@ impl<'a> Parser<'a> { let lt = self.expect_lifetime(); let (lit, _) = self.recover_unclosed_char(lt.ident, Parser::mk_token_lit_char, |self_| { - let expected = expected.unwrap_or("pattern"); + let expected = Expected::to_string_or_fallback(expected); let msg = format!( "expected {}, found {}", expected, @@ -454,15 +472,7 @@ impl<'a> Parser<'a> { self.bump(); // `...` // The user probably mistook `...` for a rest pattern `..`. - self.struct_span_err(lo, "unexpected `...`") - .span_label(lo, "not a valid pattern") - .span_suggestion_short( - lo, - "for a rest pattern, use `..` instead of `...`", - "..", - Applicability::MachineApplicable, - ) - .emit(); + self.sess.emit_err(DotDotDotRestPattern { span: lo }); PatKind::Rest } @@ -487,7 +497,7 @@ impl<'a> Parser<'a> { // At this point we attempt to parse `@ $pat_rhs` and emit an error. self.bump(); // `@` let mut rhs = self.parse_pat_no_top_alt(None)?; - let sp = lhs.span.to(rhs.span); + let whole_span = lhs.span.to(rhs.span); if let PatKind::Ident(_, _, sub @ None) = &mut rhs.kind { // The user inverted the order, so help them fix that. @@ -496,27 +506,23 @@ impl<'a> Parser<'a> { // The RHS is now the full pattern. *sub = Some(lhs); - self.struct_span_err(sp, "pattern on wrong side of `@`") - .span_label(lhs_span, "pattern on the left, should be on the right") - .span_label(rhs.span, "binding on the right, should be on the left") - .span_suggestion( - sp, - "switch the order", - pprust::pat_to_string(&rhs), - Applicability::MachineApplicable, - ) - .emit(); + self.sess.emit_err(PatternOnWrongSideOfAt { + whole_span, + whole_pat: pprust::pat_to_string(&rhs), + pattern: lhs_span, + binding: rhs.span, + }); } else { // The special case above doesn't apply so we may have e.g. `A(x) @ B(y)`. rhs.kind = PatKind::Wild; - self.struct_span_err(sp, "left-hand side of `@` must be a binding") - .span_label(lhs.span, "interpreted as a pattern, not a binding") - .span_label(rhs.span, "also a pattern") - .note("bindings are `x`, `mut x`, `ref x`, and `ref mut x`") - .emit(); + self.sess.emit_err(ExpectedBindingLeftOfAt { + whole_span, + lhs: lhs.span, + rhs: rhs.span, + }); } - rhs.span = sp; + rhs.span = whole_span; Ok(rhs) } @@ -531,35 +537,23 @@ impl<'a> Parser<'a> { _ => return, } - self.struct_span_err(pat.span, "the range pattern here has ambiguous interpretation") - .span_suggestion( - pat.span, - "add parentheses to clarify the precedence", - format!("({})", pprust::pat_to_string(&pat)), - // "ambiguous interpretation" implies that we have to be guessing - Applicability::MaybeIncorrect, - ) - .emit(); + self.sess + .emit_err(AmbiguousRangePattern { span: pat.span, pat: pprust::pat_to_string(&pat) }); } /// Parse `&pat` / `&mut pat`. - fn parse_pat_deref(&mut self, expected: Expected) -> PResult<'a, PatKind> { + fn parse_pat_deref(&mut self, expected: Option<Expected>) -> PResult<'a, PatKind> { self.expect_and()?; - self.recover_lifetime_in_deref_pat(); - let mutbl = self.parse_mutability(); - let subpat = self.parse_pat_with_range_pat(false, expected)?; - Ok(PatKind::Ref(subpat, mutbl)) - } - - fn recover_lifetime_in_deref_pat(&mut self) { if let token::Lifetime(name) = self.token.kind { self.bump(); // `'a` - let span = self.prev_token.span; - self.struct_span_err(span, &format!("unexpected lifetime `{}` in pattern", name)) - .span_suggestion(span, "remove the lifetime", "", Applicability::MachineApplicable) - .emit(); + self.sess + .emit_err(UnexpectedLifetimeInPattern { span: self.prev_token.span, symbol: name }); } + + let mutbl = self.parse_mutability(); + let subpat = self.parse_pat_with_range_pat(false, expected)?; + Ok(PatKind::Ref(subpat, mutbl)) } /// Parse a tuple or parenthesis pattern. @@ -587,7 +581,8 @@ impl<'a> Parser<'a> { let mut_span = self.prev_token.span; if self.eat_keyword(kw::Ref) { - return self.recover_mut_ref_ident(mut_span); + self.sess.emit_err(RefMutOrderIncorrect { span: mut_span.to(self.prev_token.span) }); + return self.parse_pat_ident(BindingAnnotation::REF_MUT); } self.recover_additional_muts(); @@ -600,7 +595,7 @@ impl<'a> Parser<'a> { } // Parse the pattern we hope to be an identifier. - let mut pat = self.parse_pat_no_top_alt(Some("identifier"))?; + let mut pat = self.parse_pat_no_top_alt(Some(Expected::Identifier))?; // If we don't have `mut $ident (@ pat)?`, error. if let PatKind::Ident(BindingAnnotation(ByRef::No, m @ Mutability::Not), ..) = &mut pat.kind @@ -617,22 +612,6 @@ impl<'a> Parser<'a> { Ok(pat.into_inner().kind) } - /// Recover on `mut ref? ident @ pat` and suggest - /// that the order of `mut` and `ref` is incorrect. - fn recover_mut_ref_ident(&mut self, lo: Span) -> PResult<'a, PatKind> { - let mutref_span = lo.to(self.prev_token.span); - self.struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect") - .span_suggestion( - mutref_span, - "try switching the order", - "ref mut", - Applicability::MachineApplicable, - ) - .emit(); - - self.parse_pat_ident(BindingAnnotation::REF_MUT) - } - /// Turn all by-value immutable bindings in a pattern into mutable bindings. /// Returns `true` if any change was made. fn make_all_value_bindings_mutable(pat: &mut P<Pat>) -> bool { @@ -657,16 +636,13 @@ impl<'a> Parser<'a> { /// Error on `mut $pat` where `$pat` is not an ident. fn ban_mut_general_pat(&self, lo: Span, pat: &Pat, changed_any_binding: bool) { let span = lo.to(pat.span); - let fix = pprust::pat_to_string(&pat); - let (problem, suggestion) = if changed_any_binding { - ("`mut` must be attached to each individual binding", "add `mut` to each binding") + let pat = pprust::pat_to_string(&pat); + + self.sess.emit_err(if changed_any_binding { + InvalidMutInPattern::NestedIdent { span, pat } } else { - ("`mut` must be followed by a named binding", "remove the `mut` prefix") - }; - self.struct_span_err(span, problem) - .span_suggestion(span, suggestion, fix, Applicability::MachineApplicable) - .note("`mut` may be followed by `variable` and `variable @ pattern`") - .emit(); + InvalidMutInPattern::NonIdent { span, pat } + }); } /// Eat any extraneous `mut`s and error + recover if we ate any. @@ -677,15 +653,7 @@ impl<'a> Parser<'a> { return; } - let span = lo.to(self.prev_token.span); - self.struct_span_err(span, "`mut` on a binding may not be repeated") - .span_suggestion( - span, - "remove the additional `mut`s", - "", - Applicability::MachineApplicable, - ) - .emit(); + self.sess.emit_err(RepeatedMutInPattern { span: lo.to(self.prev_token.span) }); } /// Parse macro invocation @@ -699,11 +667,11 @@ impl<'a> Parser<'a> { fn fatal_unexpected_non_pat( &mut self, err: DiagnosticBuilder<'a, ErrorGuaranteed>, - expected: Expected, + expected: Option<Expected>, ) -> PResult<'a, P<Pat>> { err.cancel(); - let expected = expected.unwrap_or("pattern"); + let expected = Expected::to_string_or_fallback(expected); let msg = format!("expected {}, found {}", expected, super::token_descr(&self.token)); let mut err = self.struct_span_err(self.token.span, &msg); @@ -745,49 +713,44 @@ impl<'a> Parser<'a> { // Parsing e.g. `X..`. if let RangeEnd::Included(_) = re.node { // FIXME(Centril): Consider semantic errors instead in `ast_validation`. - self.inclusive_range_with_incorrect_end(re.span); + self.inclusive_range_with_incorrect_end(); } None }; Ok(PatKind::Range(Some(begin), end, re)) } - pub(super) fn inclusive_range_with_incorrect_end(&mut self, span: Span) { + pub(super) fn inclusive_range_with_incorrect_end(&mut self) { let tok = &self.token; - + let span = self.prev_token.span; // If the user typed "..==" instead of "..=", we want to give them // a specific error message telling them to use "..=". + // If they typed "..=>", suggest they use ".. =>". // Otherwise, we assume that they meant to type a half open exclusive // range and give them an error telling them to do that instead. - if matches!(tok.kind, token::Eq) && tok.span.lo() == span.hi() { - let span_with_eq = span.to(tok.span); + let no_space = tok.span.lo() == span.hi(); + match tok.kind { + token::Eq if no_space => { + let span_with_eq = span.to(tok.span); - // Ensure the user doesn't receive unhelpful unexpected token errors - self.bump(); - if self.is_pat_range_end_start(0) { - let _ = self.parse_pat_range_end().map_err(|e| e.cancel()); - } + // Ensure the user doesn't receive unhelpful unexpected token errors + self.bump(); + if self.is_pat_range_end_start(0) { + let _ = self.parse_pat_range_end().map_err(|e| e.cancel()); + } - self.error_inclusive_range_with_extra_equals(span_with_eq); - } else { - self.error_inclusive_range_with_no_end(span); + self.sess.emit_err(InclusiveRangeExtraEquals { span: span_with_eq }); + } + token::Gt if no_space => { + let after_pat = span.with_hi(span.hi() - rustc_span::BytePos(1)).shrink_to_hi(); + self.sess.emit_err(InclusiveRangeMatchArrow { span, arrow: tok.span, after_pat }); + } + _ => { + self.sess.emit_err(InclusiveRangeNoEnd { span }); + } } } - fn error_inclusive_range_with_extra_equals(&self, span: Span) { - self.struct_span_err(span, "unexpected `=` after inclusive range") - .span_suggestion_short(span, "use `..=` instead", "..=", Applicability::MaybeIncorrect) - .note("inclusive ranges end with a single equals sign (`..=`)") - .emit(); - } - - fn error_inclusive_range_with_no_end(&self, span: Span) { - struct_span_err!(self.sess.span_diagnostic, span, E0586, "inclusive range with no end") - .span_suggestion_short(span, "use `..` instead", "..", Applicability::MachineApplicable) - .note("inclusive ranges must be bounded at the end (`..=b` or `a..=b`)") - .emit(); - } - /// Parse a range-to pattern, `..X` or `..=X` where `X` remains to be parsed. /// /// The form `...X` is prohibited to reduce confusion with the potential @@ -796,14 +759,7 @@ impl<'a> Parser<'a> { let end = self.parse_pat_range_end()?; if let RangeEnd::Included(syn @ RangeSyntax::DotDotDot) = &mut re.node { *syn = RangeSyntax::DotDotEq; - self.struct_span_err(re.span, "range-to patterns with `...` are not allowed") - .span_suggestion_short( - re.span, - "use `..=` instead", - "..=", - Applicability::MachineApplicable, - ) - .emit(); + self.sess.emit_err(DotDotDotRangeToPatternNotAllowed { span: re.span }); } Ok(PatKind::Range(None, Some(end), re)) } @@ -868,7 +824,7 @@ impl<'a> Parser<'a> { fn parse_pat_ident(&mut self, binding_annotation: BindingAnnotation) -> PResult<'a, PatKind> { let ident = self.parse_ident()?; let sub = if self.eat(&token::At) { - Some(self.parse_pat_no_top_alt(Some("binding pattern"))?) + Some(self.parse_pat_no_top_alt(Some(Expected::BindingPattern))?) } else { None }; @@ -879,8 +835,8 @@ impl<'a> Parser<'a> { // binding mode then we do not end up here, because the lookahead // will direct us over to `parse_enum_variant()`. if self.token == token::OpenDelim(Delimiter::Parenthesis) { - return Err(self - .struct_span_err(self.prev_token.span, "expected identifier, found enum pattern")); + return Err(EnumPatternInsteadOfIdentifier { span: self.prev_token.span } + .into_diagnostic(&self.sess.span_diagnostic)); } Ok(PatKind::Ident(binding_annotation, ident, sub)) @@ -897,7 +853,7 @@ impl<'a> Parser<'a> { e.span_label(path.span, "while parsing the fields for this pattern"); e.emit(); self.recover_stmt(); - (vec![], true) + (ThinVec::new(), true) }); self.bump(); Ok(PatKind::Struct(qself, path, fields, etc)) @@ -962,7 +918,7 @@ impl<'a> Parser<'a> { // We cannot use `parse_pat_ident()` since it will complain `box` // is not an identifier. let sub = if self.eat(&token::At) { - Some(self.parse_pat_no_top_alt(Some("binding pattern"))?) + Some(self.parse_pat_no_top_alt(Some(Expected::BindingPattern))?) } else { None }; @@ -976,8 +932,8 @@ impl<'a> Parser<'a> { } /// Parses the fields of a struct-like pattern. - fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<PatField>, bool)> { - let mut fields = Vec::new(); + fn parse_pat_fields(&mut self) -> PResult<'a, (ThinVec<PatField>, bool)> { + let mut fields = ThinVec::new(); let mut etc = false; let mut ate_comma = true; let mut delayed_err: Option<DiagnosticBuilder<'a, ErrorGuaranteed>> = None; @@ -997,7 +953,8 @@ impl<'a> Parser<'a> { // check that a comma comes after every field if !ate_comma { - let err = self.struct_span_err(self.token.span, "expected `,`"); + let err = ExpectedCommaAfterPatternField { span: self.token.span } + .into_diagnostic(&self.sess.span_diagnostic); if let Some(mut delayed) = delayed_err { delayed.emit(); } @@ -1005,12 +962,15 @@ impl<'a> Parser<'a> { } ate_comma = false; - if self.check(&token::DotDot) || self.token == token::DotDotDot { + if self.check(&token::DotDot) + || self.check_noexpect(&token::DotDotDot) + || self.check_keyword(kw::Underscore) + { etc = true; let mut etc_sp = self.token.span; - self.recover_one_fewer_dotdot(); - self.bump(); // `..` || `...` + self.recover_bad_dot_dot(); + self.bump(); // `..` || `...` || `_` if self.token == token::CloseDelim(Delimiter::Brace) { etc_span = Some(etc_sp); @@ -1103,21 +1063,15 @@ impl<'a> Parser<'a> { Ok((fields, etc)) } - /// Recover on `...` as if it were `..` to avoid further errors. + /// Recover on `...` or `_` as if it were `..` to avoid further errors. /// See issue #46718. - fn recover_one_fewer_dotdot(&self) { - if self.token != token::DotDotDot { + fn recover_bad_dot_dot(&self) { + if self.token == token::DotDot { return; } - self.struct_span_err(self.token.span, "expected field pattern, found `...`") - .span_suggestion( - self.token.span, - "to omit remaining fields, use one fewer `.`", - "..", - Applicability::MachineApplicable, - ) - .emit(); + let token_str = pprust::token_to_string(&self.token); + self.sess.emit_err(DotDotDotForRemainingFields { span: self.token.span, token_str }); } fn parse_pat_field(&mut self, lo: Span, attrs: AttrVec) -> PResult<'a, PatField> { |