From 321a5db7d4026cf703d6deebc413c855ba133142 Mon Sep 17 00:00:00 2001 From: Peter Jaszkowiak Date: Sun, 14 Apr 2024 17:37:45 -0600 Subject: Reserve guarded string literals (RFC 3593) --- compiler/rustc_parse/messages.ftl | 4 ++ compiler/rustc_parse/src/errors.rs | 18 ++++++++ compiler/rustc_parse/src/lexer/mod.rs | 84 ++++++++++++++++++++++++++++++++++- 3 files changed, 105 insertions(+), 1 deletion(-) (limited to 'compiler/rustc_parse') diff --git a/compiler/rustc_parse/messages.ftl b/compiler/rustc_parse/messages.ftl index 948199fd55c..ba5e2ddf4fc 100644 --- a/compiler/rustc_parse/messages.ftl +++ b/compiler/rustc_parse/messages.ftl @@ -706,6 +706,10 @@ parse_require_colon_after_labeled_expression = labeled expression must be follow .label = the label .suggestion = add `:` after the label +parse_reserved_string = invalid string literal + .note = unprefixed guarded string literals are reserved for future use since Rust 2024 + .suggestion_whitespace = consider inserting whitespace here + parse_return_types_use_thin_arrow = return types are denoted using `->` .suggestion = use `->` instead diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs index dade3912751..124975f67f1 100644 --- a/compiler/rustc_parse/src/errors.rs +++ b/compiler/rustc_parse/src/errors.rs @@ -2110,6 +2110,24 @@ pub(crate) enum UnknownPrefixSugg { }, } +#[derive(Diagnostic)] +#[diag(parse_reserved_string)] +#[note] +pub(crate) struct ReservedString { + #[primary_span] + pub span: Span, + #[subdiagnostic] + pub sugg: Option, +} +#[derive(Subdiagnostic)] +#[suggestion( + parse_suggestion_whitespace, + code = " ", + applicability = "maybe-incorrect", + style = "verbose" +)] +pub(crate) struct GuardedStringSugg(#[primary_span] pub Span); + #[derive(Diagnostic)] #[diag(parse_too_many_hashes)] pub(crate) struct TooManyHashes { diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs index 3e46fc93fa4..d627ef3d2cb 100644 --- a/compiler/rustc_parse/src/lexer/mod.rs +++ b/compiler/rustc_parse/src/lexer/mod.rs @@ -10,7 +10,8 @@ use rustc_lexer::unescape::{self, EscapeError, Mode}; use rustc_lexer::{Base, Cursor, DocStyle, LiteralKind, RawStrError}; use rustc_session::lint::BuiltinLintDiag; use rustc_session::lint::builtin::{ - RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX, TEXT_DIRECTION_CODEPOINT_IN_COMMENT, + RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX, RUST_2024_GUARDED_STRING_INCOMPATIBLE_SYNTAX, + TEXT_DIRECTION_CODEPOINT_IN_COMMENT, }; use rustc_session::parse::ParseSess; use rustc_span::symbol::Symbol; @@ -251,6 +252,7 @@ impl<'psess, 'src> StringReader<'psess, 'src> { let prefix_span = self.mk_sp(start, lit_start); return (Token::new(self.ident(start), prefix_span), preceded_by_whitespace); } + rustc_lexer::TokenKind::GuardedStrPrefix => self.maybe_report_guarded_str(start, str_before), rustc_lexer::TokenKind::Literal { kind, suffix_start } => { let suffix_start = start + BytePos(suffix_start); let (kind, symbol) = self.cook_lexer_literal(start, suffix_start, kind); @@ -781,6 +783,86 @@ impl<'psess, 'src> StringReader<'psess, 'src> { } } + /// Detect guarded string literal syntax + /// + /// RFC 3598 reserved this syntax for future use. As of Rust 2024, + /// using this syntax produces an error. In earlier editions, however, it + /// only results in an (allowed by default) lint, and is treated as + /// separate tokens. + fn maybe_report_guarded_str(&mut self, start: BytePos, str_before: &'src str) -> TokenKind { + let span = self.mk_sp(start, self.pos); + let edition2024 = span.edition().at_least_rust_2024(); + + let space_pos = start + BytePos(1); + let space_span = self.mk_sp(space_pos, space_pos); + + let mut cursor = Cursor::new(str_before); + + let (span, unterminated) = match cursor.guarded_double_quoted_string() { + Some(rustc_lexer::GuardedStr { n_hashes, terminated, token_len }) => { + let end = start + BytePos(token_len); + let span = self.mk_sp(start, end); + let str_start = start + BytePos(n_hashes); + + if edition2024 { + self.cursor = cursor; + self.pos = end; + } + + let unterminated = if terminated { None } else { Some(str_start) }; + + (span, unterminated) + } + _ => { + // We should only get here in the `##+` case. + debug_assert_eq!(self.str_from_to(start, start + BytePos(2)), "##"); + + (span, None) + } + }; + if edition2024 { + if let Some(str_start) = unterminated { + // Only a fatal error if string is unterminated. + self.dcx() + .struct_span_fatal( + self.mk_sp(str_start, self.pos), + "unterminated double quote string", + ) + .with_code(E0765) + .emit() + } + + let sugg = if span.from_expansion() { + None + } else { + Some(errors::GuardedStringSugg(space_span)) + }; + + // In Edition 2024 and later, emit a hard error. + let err = self.dcx().emit_err(errors::ReservedString { span, sugg }); + + token::Literal(token::Lit { + kind: token::Err(err), + symbol: self.symbol_from_to(start, self.pos), + suffix: None, + }) + } else { + // Before Rust 2024, only emit a lint for migration. + self.psess.buffer_lint( + RUST_2024_GUARDED_STRING_INCOMPATIBLE_SYNTAX, + span, + ast::CRATE_NODE_ID, + BuiltinLintDiag::ReservedString(space_span), + ); + + // For backwards compatibility, roll back to after just the first `#` + // and return the `Pound` token. + self.pos = start + BytePos(1); + self.cursor = Cursor::new(&str_before[1..]); + token::Pound + } + } + fn report_too_many_hashes(&self, start: BytePos, num: u32) -> ! { self.dcx().emit_fatal(errors::TooManyHashes { span: self.mk_sp(start, self.pos), num }); } -- cgit 1.4.1-3-g733a5