From 9cd668beed38a8e98933733854a224c70998bf16 Mon Sep 17 00:00:00 2001 From: Pavel Grigorenko Date: Mon, 23 Sep 2024 02:12:53 +0300 Subject: [PATCH] Parser: better error messages for `@` in struct patterns --- compiler/rustc_parse/messages.ftl | 7 ++ compiler/rustc_parse/src/errors.rs | 19 +++++ compiler/rustc_parse/src/parser/pat.rs | 54 +++++++++++---- tests/ui/pattern/at-in-struct-patterns.rs | 14 ++++ tests/ui/pattern/at-in-struct-patterns.stderr | 69 +++++++++++++++++++ 5 files changed, 150 insertions(+), 13 deletions(-) create mode 100644 tests/ui/pattern/at-in-struct-patterns.rs create mode 100644 tests/ui/pattern/at-in-struct-patterns.stderr diff --git a/compiler/rustc_parse/messages.ftl b/compiler/rustc_parse/messages.ftl index 6cb851eb8df..5d1c300b453 100644 --- a/compiler/rustc_parse/messages.ftl +++ b/compiler/rustc_parse/messages.ftl @@ -26,6 +26,13 @@ parse_async_move_block_in_2015 = `async move` blocks are only allowed in Rust 20 parse_async_move_order_incorrect = the order of `move` and `async` is incorrect .suggestion = try switching the order +parse_at_dot_dot_in_struct_pattern = `@ ..` is not supported in struct patterns + .suggestion = bind to each field separately or, if you don't need them, just remove `{$ident} @` + +parse_at_in_struct_pattern = Unexpected `@` in struct pattern + .note = struct patterns use `field: pattern` syntax to bind to fields + .help = consider replacing `new_name @ field_name` with `field_name: new_name` if that is what you intended + parse_attr_after_generic = trailing attribute after generic parameter .label = attributes must go before parameters diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs index e9fe2e6c1dd..e16ab5b4b06 100644 --- a/compiler/rustc_parse/src/errors.rs +++ b/compiler/rustc_parse/src/errors.rs @@ -2583,6 +2583,25 @@ pub(crate) struct EnumPatternInsteadOfIdentifier { pub span: Span, } +#[derive(Diagnostic)] +#[diag(parse_at_dot_dot_in_struct_pattern)] +pub(crate) struct AtDotDotInStructPattern { + #[primary_span] + pub span: Span, + #[suggestion(code = "", style = "verbose", applicability = "machine-applicable")] + pub remove: Span, + pub ident: Ident, +} + +#[derive(Diagnostic)] +#[diag(parse_at_in_struct_pattern)] +#[note] +#[help] +pub(crate) struct AtInStructPattern { + #[primary_span] + pub span: Span, +} + #[derive(Diagnostic)] #[diag(parse_dot_dot_dot_for_remaining_fields)] pub(crate) struct DotDotDotForRemainingFields { diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs index 647df25c82e..b4cbe1accf4 100644 --- a/compiler/rustc_parse/src/parser/pat.rs +++ b/compiler/rustc_parse/src/parser/pat.rs @@ -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, PatFieldsRest)> { - let mut fields = ThinVec::new(); + let mut fields: ThinVec = ThinVec::new(); let mut etc = PatFieldsRest::None; let mut ate_comma = true; let mut delayed_err: Option> = 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, err: &mut Diag<'a>) { diff --git a/tests/ui/pattern/at-in-struct-patterns.rs b/tests/ui/pattern/at-in-struct-patterns.rs new file mode 100644 index 00000000000..e8fad61f317 --- /dev/null +++ b/tests/ui/pattern/at-in-struct-patterns.rs @@ -0,0 +1,14 @@ +struct Foo { + field1: u8, + field2: u8, +} + +fn main() { + let foo = Foo { field1: 1, field2: 2 }; + let Foo { var @ field1, .. } = foo; //~ ERROR Unexpected `@` in struct pattern + dbg!(var); //~ ERROR cannot find value `var` in this scope + let Foo { field1: _, bar @ .. } = foo; //~ ERROR `@ ..` is not supported in struct patterns + let Foo { bar @ .. } = foo; //~ ERROR `@ ..` is not supported in struct patterns + let Foo { @ } = foo; //~ ERROR expected identifier, found `@` + let Foo { @ .. } = foo; //~ ERROR expected identifier, found `@` +} diff --git a/tests/ui/pattern/at-in-struct-patterns.stderr b/tests/ui/pattern/at-in-struct-patterns.stderr new file mode 100644 index 00000000000..ff75edfe681 --- /dev/null +++ b/tests/ui/pattern/at-in-struct-patterns.stderr @@ -0,0 +1,69 @@ +error: Unexpected `@` in struct pattern + --> $DIR/at-in-struct-patterns.rs:8:15 + | +LL | let Foo { var @ field1, .. } = foo; + | --- ^^^^^ + | | + | while parsing the fields for this pattern + | + = note: struct patterns use `field: pattern` syntax to bind to fields + = help: consider replacing `new_name @ field_name` with `field_name: new_name` if that is what you intended + +error: `@ ..` is not supported in struct patterns + --> $DIR/at-in-struct-patterns.rs:10:26 + | +LL | let Foo { field1: _, bar @ .. } = foo; + | --- ^^^^^^^^ + | | + | while parsing the fields for this pattern + | +help: bind to each field separately or, if you don't need them, just remove `bar @` + | +LL - let Foo { field1: _, bar @ .. } = foo; +LL + let Foo { field1: _, .. } = foo; + | + +error: `@ ..` is not supported in struct patterns + --> $DIR/at-in-struct-patterns.rs:11:15 + | +LL | let Foo { bar @ .. } = foo; + | --- ^^^^^^^^ + | | + | while parsing the fields for this pattern + | +help: bind to each field separately or, if you don't need them, just remove `bar @` + | +LL - let Foo { bar @ .. } = foo; +LL + let Foo { .. } = foo; + | + +error: expected identifier, found `@` + --> $DIR/at-in-struct-patterns.rs:12:15 + | +LL | let Foo { @ } = foo; + | --- ^ expected identifier + | | + | while parsing the fields for this pattern + +error: expected identifier, found `@` + --> $DIR/at-in-struct-patterns.rs:13:15 + | +LL | let Foo { @ .. } = foo; + | --- ^ expected identifier + | | + | while parsing the fields for this pattern + +error[E0425]: cannot find value `var` in this scope + --> $DIR/at-in-struct-patterns.rs:9:10 + | +LL | dbg!(var); + | ^^^ not found in this scope + | +help: consider importing this function + | +LL + use std::env::var; + | + +error: aborting due to 6 previous errors + +For more information about this error, try `rustc --explain E0425`.