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Parser: better error messages for @ in struct patterns

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This commit is contained in:
Pavel Grigorenko 2024-09-23 02:12:53 +03:00
parent 8ed95d1d9e
commit 9cd668beed
5 changed files with 150 additions and 13 deletions
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54
compiler/rustc_parse/src/parser/pat.rs
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@ -17,15 +17,16 @@ use thin_vec::{thin_vec, ThinVec};
use super::{ForceCollect, Parser, PathStyle, Restrictions, Trailing, UsePreAttrPos};
use crate::errors::{
self, AmbiguousRangePattern, DotDotDotForRemainingFields, DotDotDotRangeToPatternNotAllowed,
DotDotDotRestPattern, EnumPatternInsteadOfIdentifier, ExpectedBindingLeftOfAt,
ExpectedCommaAfterPatternField, GenericArgsInPatRequireTurbofishSyntax,
InclusiveRangeExtraEquals, InclusiveRangeMatchArrow, InclusiveRangeNoEnd, InvalidMutInPattern,
ParenRangeSuggestion, PatternOnWrongSideOfAt, RemoveLet, RepeatedMutInPattern,
SwitchRefBoxOrder, TopLevelOrPatternNotAllowed, TopLevelOrPatternNotAllowedSugg,
TrailingVertNotAllowed, UnexpectedExpressionInPattern, UnexpectedExpressionInPatternSugg,
UnexpectedLifetimeInPattern, UnexpectedParenInRangePat, UnexpectedParenInRangePatSugg,
UnexpectedVertVertBeforeFunctionParam, UnexpectedVertVertInPattern, WrapInParens,
self, AmbiguousRangePattern, AtDotDotInStructPattern, AtInStructPattern,
DotDotDotForRemainingFields, DotDotDotRangeToPatternNotAllowed, DotDotDotRestPattern,
EnumPatternInsteadOfIdentifier, ExpectedBindingLeftOfAt, ExpectedCommaAfterPatternField,
GenericArgsInPatRequireTurbofishSyntax, InclusiveRangeExtraEquals, InclusiveRangeMatchArrow,
InclusiveRangeNoEnd, InvalidMutInPattern, ParenRangeSuggestion, PatternOnWrongSideOfAt,
RemoveLet, RepeatedMutInPattern, SwitchRefBoxOrder, TopLevelOrPatternNotAllowed,
TopLevelOrPatternNotAllowedSugg, TrailingVertNotAllowed, UnexpectedExpressionInPattern,
UnexpectedExpressionInPatternSugg, UnexpectedLifetimeInPattern, UnexpectedParenInRangePat,
UnexpectedParenInRangePatSugg, UnexpectedVertVertBeforeFunctionParam,
UnexpectedVertVertInPattern, WrapInParens,
};
use crate::parser::expr::{could_be_unclosed_char_literal, DestructuredFloat};
use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
@ -1433,7 +1434,7 @@ impl<'a> Parser<'a> {
/// Parses the fields of a struct-like pattern.
fn parse_pat_fields(&mut self) -> PResult<'a, (ThinVec<PatField>, PatFieldsRest)> {
let mut fields = ThinVec::new();
let mut fields: ThinVec<PatField> = ThinVec::new();
let mut etc = PatFieldsRest::None;
let mut ate_comma = true;
let mut delayed_err: Option<Diag<'a>> = None;
@ -1454,12 +1455,22 @@ impl<'a> Parser<'a> {
// check that a comma comes after every field
if !ate_comma {
let mut err =
self.dcx().create_err(ExpectedCommaAfterPatternField { span: self.token.span });
let err = if self.token == token::At {
let prev_field = fields
.last()
.expect("Unreachable on first iteration, not empty otherwise")
.ident;
self.report_misplaced_at_in_struct_pat(prev_field)
} else {
let mut err = self
.dcx()
.create_err(ExpectedCommaAfterPatternField { span: self.token.span });
self.recover_misplaced_pattern_modifiers(&fields, &mut err);
err
};
if let Some(delayed) = delayed_err {
delayed.emit();
}
self.recover_misplaced_pattern_modifiers(&fields, &mut err);
return Err(err);
}
ate_comma = false;
@ -1594,6 +1605,23 @@ impl<'a> Parser<'a> {
Ok((fields, etc))
}
#[deny(rustc::untranslatable_diagnostic)]
fn report_misplaced_at_in_struct_pat(&self, prev_field: Ident) -> Diag<'a> {
debug_assert_eq!(self.token, token::At);
let span = prev_field.span.to(self.token.span);
if let Some(dot_dot_span) =
self.look_ahead(1, |t| if t == &token::DotDot { Some(t.span) } else { None })
{
self.dcx().create_err(AtDotDotInStructPattern {
span: span.to(dot_dot_span),
remove: span.until(dot_dot_span),
ident: prev_field,
})
} else {
self.dcx().create_err(AtInStructPattern { span: span })
}
}
/// If the user writes `S { ref field: name }` instead of `S { field: ref name }`, we suggest
/// the correct code.
fn recover_misplaced_pattern_modifiers(&self, fields: &ThinVec<PatField>, err: &mut Diag<'a>) {