From 2c9602587472a94afc595f0f5adc7a0b85e15201 Mon Sep 17 00:00:00 2001 From: Carter Hunt Fogelman Date: Wed, 6 Dec 2023 16:56:45 -0800 Subject: Improve compiler error for c-strings in pre-2021 --- compiler/rustc_parse/src/parser/diagnostics.rs | 36 +++++++++++++++++++++----- 1 file changed, 29 insertions(+), 7 deletions(-) (limited to 'compiler/rustc_parse/src/parser') diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs index 7ab0d3f35ea..5770c038e9e 100644 --- a/compiler/rustc_parse/src/parser/diagnostics.rs +++ b/compiler/rustc_parse/src/parser/diagnostics.rs @@ -10,13 +10,13 @@ use crate::errors::{ ConstGenericWithoutBracesSugg, DocCommentDoesNotDocumentAnything, DocCommentOnParamType, DoubleColonInBound, ExpectedIdentifier, ExpectedSemi, ExpectedSemiSugg, GenericParamsWithoutAngleBrackets, GenericParamsWithoutAngleBracketsSugg, - HelpIdentifierStartsWithNumber, InInTypo, IncorrectAwait, IncorrectSemicolon, - IncorrectUseOfAwait, PatternMethodParamWithoutBody, QuestionMarkInType, QuestionMarkInTypeSugg, - SelfParamNotFirst, StructLiteralBodyWithoutPath, StructLiteralBodyWithoutPathSugg, - StructLiteralNeedingParens, StructLiteralNeedingParensSugg, SuggAddMissingLetStmt, - SuggEscapeIdentifier, SuggRemoveComma, TernaryOperator, UnexpectedConstInGenericParam, - UnexpectedConstParamDeclaration, UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, - UseEqInstead, WrapType, + HelpIdentifierStartsWithNumber, HelpUseLatestEdition, InInTypo, IncorrectAwait, + IncorrectSemicolon, IncorrectUseOfAwait, PatternMethodParamWithoutBody, QuestionMarkInType, + QuestionMarkInTypeSugg, SelfParamNotFirst, StructLiteralBodyWithoutPath, + StructLiteralBodyWithoutPathSugg, StructLiteralNeedingParens, StructLiteralNeedingParensSugg, + SuggAddMissingLetStmt, SuggEscapeIdentifier, SuggRemoveComma, TernaryOperator, + UnexpectedConstInGenericParam, UnexpectedConstParamDeclaration, + UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead, WrapType, }; use crate::fluent_generated as fluent; use crate::parser; @@ -640,6 +640,28 @@ impl<'a> Parser<'a> { } } + // Try to detect an intended c-string literal while using a pre-2021 edition. The heuristic + // here is to identify a cooked, uninterpolated `c` id immediately followed by a string, or + // a cooked, uninterpolated `cr` id immediately followed by a string or a `#`, in an edition + // where c-string literals are not allowed. There is the very slight possibility of a false + // positive for a `cr#` that wasn't intended to start a c-string literal, but identifying + // that in the parser requires unbounded lookahead, so we only add a hint to the existing + // error rather than replacing it entirely. + if ((self.prev_token.kind == TokenKind::Ident(sym::c, false) + && matches!(&self.token.kind, TokenKind::Literal(token::Lit { kind: token::Str, .. }))) + || (self.prev_token.kind == TokenKind::Ident(sym::cr, false) + && matches!( + &self.token.kind, + TokenKind::Literal(token::Lit { kind: token::Str, .. }) | token::Pound + ))) + && self.prev_token.span.hi() == self.token.span.lo() + && !self.token.span.at_least_rust_2021() + { + err.note("you may be trying to write a c-string literal"); + err.note("c-string literals require Rust 2021 or later"); + HelpUseLatestEdition::new().add_to_diagnostic(&mut err); + } + // `pub` may be used for an item or `pub(crate)` if self.prev_token.is_ident_named(sym::public) && (self.token.can_begin_item() -- cgit 1.4.1-3-g733a5