| use std::ops::Range; |
| |
| use parse::Position::ArgumentNamed; |
| use rustc_ast::ptr::P; |
| use rustc_ast::tokenstream::TokenStream; |
| use rustc_ast::{ |
| Expr, ExprKind, FormatAlignment, FormatArgPosition, FormatArgPositionKind, FormatArgs, |
| FormatArgsPiece, FormatArgument, FormatArgumentKind, FormatArguments, FormatCount, |
| FormatDebugHex, FormatOptions, FormatPlaceholder, FormatSign, FormatTrait, Recovered, StmtKind, |
| token, |
| }; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_errors::{ |
| Applicability, Diag, MultiSpan, PResult, SingleLabelManySpans, listify, pluralize, |
| }; |
| use rustc_expand::base::*; |
| use rustc_lint_defs::builtin::NAMED_ARGUMENTS_USED_POSITIONALLY; |
| use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiag, LintId}; |
| use rustc_parse::exp; |
| use rustc_parse_format as parse; |
| use rustc_span::{BytePos, ErrorGuaranteed, Ident, InnerSpan, Span, Symbol}; |
| |
| use crate::errors; |
| use crate::util::{ExprToSpannedString, expr_to_spanned_string}; |
| |
| // The format_args!() macro is expanded in three steps: |
| // 1. First, `parse_args` will parse the `(literal, arg, arg, name=arg, name=arg)` syntax, |
| // but doesn't parse the template (the literal) itself. |
| // 2. Second, `make_format_args` will parse the template, the format options, resolve argument references, |
| // produce diagnostics, and turn the whole thing into a `FormatArgs` AST node. |
| // 3. Much later, in AST lowering (rustc_ast_lowering), that `FormatArgs` structure will be turned |
| // into the expression of type `core::fmt::Arguments`. |
| |
| // See rustc_ast/src/format.rs for the FormatArgs structure and glossary. |
| |
| // Only used in parse_args and report_invalid_references, |
| // to indicate how a referred argument was used. |
| #[derive(Clone, Copy, Debug, PartialEq, Eq)] |
| enum PositionUsedAs { |
| Placeholder(Option<Span>), |
| Precision, |
| Width, |
| } |
| use PositionUsedAs::*; |
| |
| #[derive(Debug)] |
| struct MacroInput { |
| fmtstr: P<Expr>, |
| args: FormatArguments, |
| /// Whether the first argument was a string literal or a result from eager macro expansion. |
| /// If it's not a string literal, we disallow implicit argument capturing. |
| /// |
| /// This does not correspond to whether we can treat spans to the literal normally, as the whole |
| /// invocation might be the result of another macro expansion, in which case this flag may still be true. |
| /// |
| /// See [RFC 2795] for more information. |
| /// |
| /// [RFC 2795]: https://rust-lang.github.io/rfcs/2795-format-args-implicit-identifiers.html#macro-hygiene |
| is_direct_literal: bool, |
| } |
| |
| /// Parses the arguments from the given list of tokens, returning the diagnostic |
| /// if there's a parse error so we can continue parsing other format! |
| /// expressions. |
| /// |
| /// If parsing succeeds, the return value is: |
| /// |
| /// ```text |
| /// Ok((fmtstr, parsed arguments)) |
| /// ``` |
| fn parse_args<'a>(ecx: &ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<'a, MacroInput> { |
| let mut args = FormatArguments::new(); |
| |
| let mut p = ecx.new_parser_from_tts(tts); |
| |
| if p.token == token::Eof { |
| return Err(ecx.dcx().create_err(errors::FormatRequiresString { span: sp })); |
| } |
| |
| let first_token = &p.token; |
| |
| let fmtstr = if let token::Literal(lit) = first_token.kind |
| && matches!(lit.kind, token::Str | token::StrRaw(_)) |
| { |
| // This allows us to properly handle cases when the first comma |
| // after the format string is mistakenly replaced with any operator, |
| // which cause the expression parser to eat too much tokens. |
| p.parse_literal_maybe_minus()? |
| } else { |
| // Otherwise, we fall back to the expression parser. |
| p.parse_expr()? |
| }; |
| |
| // Only allow implicit captures to be used when the argument is a direct literal |
| // instead of a macro expanding to one. |
| let is_direct_literal = matches!(fmtstr.kind, ExprKind::Lit(_)); |
| |
| let mut first = true; |
| |
| while p.token != token::Eof { |
| if !p.eat(exp!(Comma)) { |
| if first { |
| p.clear_expected_token_types(); |
| } |
| |
| match p.expect(exp!(Comma)) { |
| Err(err) => { |
| if token::TokenKind::Comma.similar_tokens().contains(&p.token.kind) { |
| // If a similar token is found, then it may be a typo. We |
| // consider it as a comma, and continue parsing. |
| err.emit(); |
| p.bump(); |
| } else { |
| // Otherwise stop the parsing and return the error. |
| return Err(err); |
| } |
| } |
| Ok(Recovered::Yes(_)) => (), |
| Ok(Recovered::No) => unreachable!(), |
| } |
| } |
| first = false; |
| if p.token == token::Eof { |
| break; |
| } // accept trailing commas |
| match p.token.ident() { |
| Some((ident, _)) if p.look_ahead(1, |t| *t == token::Eq) => { |
| p.bump(); |
| p.expect(exp!(Eq))?; |
| let expr = p.parse_expr()?; |
| if let Some((_, prev)) = args.by_name(ident.name) { |
| ecx.dcx().emit_err(errors::FormatDuplicateArg { |
| span: ident.span, |
| prev: prev.kind.ident().unwrap().span, |
| duplicate: ident.span, |
| ident, |
| }); |
| continue; |
| } |
| args.add(FormatArgument { kind: FormatArgumentKind::Named(ident), expr }); |
| } |
| _ => { |
| let expr = p.parse_expr()?; |
| if !args.named_args().is_empty() { |
| return Err(ecx.dcx().create_err(errors::PositionalAfterNamed { |
| span: expr.span, |
| args: args |
| .named_args() |
| .iter() |
| .filter_map(|a| a.kind.ident().map(|ident| (a, ident))) |
| .map(|(arg, n)| n.span.to(arg.expr.span)) |
| .collect(), |
| })); |
| } |
| args.add(FormatArgument { kind: FormatArgumentKind::Normal, expr }); |
| } |
| } |
| } |
| Ok(MacroInput { fmtstr, args, is_direct_literal }) |
| } |
| |
| fn make_format_args( |
| ecx: &mut ExtCtxt<'_>, |
| input: MacroInput, |
| append_newline: bool, |
| ) -> ExpandResult<Result<FormatArgs, ErrorGuaranteed>, ()> { |
| let msg = "format argument must be a string literal"; |
| let unexpanded_fmt_span = input.fmtstr.span; |
| |
| let MacroInput { fmtstr: efmt, mut args, is_direct_literal } = input; |
| |
| let ExprToSpannedString { |
| symbol: fmt_str, |
| span: fmt_span, |
| style: fmt_style, |
| uncooked_symbol: uncooked_fmt_str, |
| } = { |
| let ExpandResult::Ready(mac) = expr_to_spanned_string(ecx, efmt.clone(), msg) else { |
| return ExpandResult::Retry(()); |
| }; |
| match mac { |
| Ok(mut fmt) if append_newline => { |
| fmt.symbol = Symbol::intern(&format!("{}\n", fmt.symbol)); |
| fmt |
| } |
| Ok(fmt) => fmt, |
| Err(err) => { |
| let guar = match err { |
| Ok((mut err, suggested)) => { |
| if !suggested { |
| if let ExprKind::Block(block, None) = &efmt.kind |
| && let [stmt] = block.stmts.as_slice() |
| && let StmtKind::Expr(expr) = &stmt.kind |
| && let ExprKind::Path(None, path) = &expr.kind |
| && path.segments.len() == 1 |
| && path.segments[0].args.is_none() |
| { |
| err.multipart_suggestion( |
| "quote your inlined format argument to use as string literal", |
| vec![ |
| (unexpanded_fmt_span.shrink_to_hi(), "\"".to_string()), |
| (unexpanded_fmt_span.shrink_to_lo(), "\"".to_string()), |
| ], |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| // `{}` or `()` |
| let should_suggest = |kind: &ExprKind| -> bool { |
| match kind { |
| ExprKind::Block(b, None) if b.stmts.is_empty() => true, |
| ExprKind::Tup(v) if v.is_empty() => true, |
| _ => false, |
| } |
| }; |
| |
| let mut sugg_fmt = String::new(); |
| for kind in std::iter::once(&efmt.kind) |
| .chain(args.explicit_args().into_iter().map(|a| &a.expr.kind)) |
| { |
| sugg_fmt.push_str(if should_suggest(kind) { |
| "{:?} " |
| } else { |
| "{} " |
| }); |
| } |
| sugg_fmt = sugg_fmt.trim_end().to_string(); |
| err.span_suggestion( |
| unexpanded_fmt_span.shrink_to_lo(), |
| "you might be missing a string literal to format with", |
| format!("\"{sugg_fmt}\", "), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| err.emit() |
| } |
| Err(guar) => guar, |
| }; |
| return ExpandResult::Ready(Err(guar)); |
| } |
| } |
| }; |
| |
| let str_style = match fmt_style { |
| rustc_ast::StrStyle::Cooked => None, |
| rustc_ast::StrStyle::Raw(raw) => Some(raw as usize), |
| }; |
| |
| let fmt_str = fmt_str.as_str(); // for the suggestions below |
| let fmt_snippet = ecx.source_map().span_to_snippet(unexpanded_fmt_span).ok(); |
| let mut parser = parse::Parser::new( |
| fmt_str, |
| str_style, |
| fmt_snippet, |
| append_newline, |
| parse::ParseMode::Format, |
| ); |
| |
| let mut pieces = Vec::new(); |
| while let Some(piece) = parser.next() { |
| if !parser.errors.is_empty() { |
| break; |
| } else { |
| pieces.push(piece); |
| } |
| } |
| |
| let is_source_literal = parser.is_source_literal; |
| |
| if !parser.errors.is_empty() { |
| let err = parser.errors.remove(0); |
| let sp = if is_source_literal { |
| fmt_span.from_inner(InnerSpan::new(err.span.start, err.span.end)) |
| } else { |
| // The format string could be another macro invocation, e.g.: |
| // format!(concat!("abc", "{}"), 4); |
| // However, `err.span` is an inner span relative to the *result* of |
| // the macro invocation, which is why we would get a nonsensical |
| // result calling `fmt_span.from_inner(err.span)` as above, and |
| // might even end up inside a multibyte character (issue #86085). |
| // Therefore, we conservatively report the error for the entire |
| // argument span here. |
| fmt_span |
| }; |
| let mut e = errors::InvalidFormatString { |
| span: sp, |
| note_: None, |
| label_: None, |
| sugg_: None, |
| desc: err.description, |
| label1: err.label, |
| }; |
| if let Some(note) = err.note { |
| e.note_ = Some(errors::InvalidFormatStringNote { note }); |
| } |
| if let Some((label, span)) = err.secondary_label |
| && is_source_literal |
| { |
| e.label_ = Some(errors::InvalidFormatStringLabel { |
| span: fmt_span.from_inner(InnerSpan::new(span.start, span.end)), |
| label, |
| }); |
| } |
| match err.suggestion { |
| parse::Suggestion::None => {} |
| parse::Suggestion::UsePositional => { |
| let captured_arg_span = |
| fmt_span.from_inner(InnerSpan::new(err.span.start, err.span.end)); |
| if let Ok(arg) = ecx.source_map().span_to_snippet(captured_arg_span) { |
| let span = match args.unnamed_args().last() { |
| Some(arg) => arg.expr.span, |
| None => fmt_span, |
| }; |
| e.sugg_ = Some(errors::InvalidFormatStringSuggestion::UsePositional { |
| captured: captured_arg_span, |
| len: args.unnamed_args().len().to_string(), |
| span: span.shrink_to_hi(), |
| arg, |
| }); |
| } |
| } |
| parse::Suggestion::RemoveRawIdent(span) => { |
| if is_source_literal { |
| let span = fmt_span.from_inner(InnerSpan::new(span.start, span.end)); |
| e.sugg_ = Some(errors::InvalidFormatStringSuggestion::RemoveRawIdent { span }) |
| } |
| } |
| parse::Suggestion::ReorderFormatParameter(span, replacement) => { |
| let span = fmt_span.from_inner(InnerSpan::new(span.start, span.end)); |
| e.sugg_ = Some(errors::InvalidFormatStringSuggestion::ReorderFormatParameter { |
| span, |
| replacement, |
| }); |
| } |
| } |
| let guar = ecx.dcx().emit_err(e); |
| return ExpandResult::Ready(Err(guar)); |
| } |
| |
| let to_span = |inner_span: Range<usize>| { |
| is_source_literal.then(|| { |
| fmt_span.from_inner(InnerSpan { start: inner_span.start, end: inner_span.end }) |
| }) |
| }; |
| |
| let mut used = vec![false; args.explicit_args().len()]; |
| let mut invalid_refs = Vec::new(); |
| let mut numeric_references_to_named_arg = Vec::new(); |
| |
| enum ArgRef<'a> { |
| Index(usize), |
| Name(&'a str, Option<Span>), |
| } |
| use ArgRef::*; |
| |
| let mut unnamed_arg_after_named_arg = false; |
| |
| let mut lookup_arg = |arg: ArgRef<'_>, |
| span: Option<Span>, |
| used_as: PositionUsedAs, |
| kind: FormatArgPositionKind| |
| -> FormatArgPosition { |
| let index = match arg { |
| Index(index) => { |
| if let Some(arg) = args.by_index(index) { |
| used[index] = true; |
| if arg.kind.ident().is_some() { |
| // This was a named argument, but it was used as a positional argument. |
| numeric_references_to_named_arg.push((index, span, used_as)); |
| } |
| Ok(index) |
| } else { |
| // Doesn't exist as an explicit argument. |
| invalid_refs.push((index, span, used_as, kind)); |
| Err(index) |
| } |
| } |
| Name(name, span) => { |
| let name = Symbol::intern(name); |
| if let Some((index, _)) = args.by_name(name) { |
| // Name found in `args`, so we resolve it to its index. |
| if index < args.explicit_args().len() { |
| // Mark it as used, if it was an explicit argument. |
| used[index] = true; |
| } |
| Ok(index) |
| } else { |
| // Name not found in `args`, so we add it as an implicitly captured argument. |
| let span = span.unwrap_or(fmt_span); |
| let ident = Ident::new(name, span); |
| let expr = if is_direct_literal { |
| ecx.expr_ident(span, ident) |
| } else { |
| // For the moment capturing variables from format strings expanded from macros is |
| // disabled (see RFC #2795) |
| let guar = ecx.dcx().emit_err(errors::FormatNoArgNamed { span, name }); |
| unnamed_arg_after_named_arg = true; |
| DummyResult::raw_expr(span, Some(guar)) |
| }; |
| Ok(args.add(FormatArgument { kind: FormatArgumentKind::Captured(ident), expr })) |
| } |
| } |
| }; |
| FormatArgPosition { index, kind, span } |
| }; |
| |
| let mut template = Vec::new(); |
| let mut unfinished_literal = String::new(); |
| let mut placeholder_index = 0; |
| |
| for piece in &pieces { |
| match piece.clone() { |
| parse::Piece::Lit(s) => { |
| unfinished_literal.push_str(s); |
| } |
| parse::Piece::NextArgument(box parse::Argument { position, position_span, format }) => { |
| if !unfinished_literal.is_empty() { |
| template.push(FormatArgsPiece::Literal(Symbol::intern(&unfinished_literal))); |
| unfinished_literal.clear(); |
| } |
| |
| let span = |
| parser.arg_places.get(placeholder_index).and_then(|s| to_span(s.clone())); |
| placeholder_index += 1; |
| |
| let position_span = to_span(position_span); |
| let argument = match position { |
| parse::ArgumentImplicitlyIs(i) => lookup_arg( |
| Index(i), |
| position_span, |
| Placeholder(span), |
| FormatArgPositionKind::Implicit, |
| ), |
| parse::ArgumentIs(i) => lookup_arg( |
| Index(i), |
| position_span, |
| Placeholder(span), |
| FormatArgPositionKind::Number, |
| ), |
| parse::ArgumentNamed(name) => lookup_arg( |
| Name(name, position_span), |
| position_span, |
| Placeholder(span), |
| FormatArgPositionKind::Named, |
| ), |
| }; |
| |
| let alignment = match format.align { |
| parse::AlignUnknown => None, |
| parse::AlignLeft => Some(FormatAlignment::Left), |
| parse::AlignRight => Some(FormatAlignment::Right), |
| parse::AlignCenter => Some(FormatAlignment::Center), |
| }; |
| |
| let format_trait = match format.ty { |
| "" => FormatTrait::Display, |
| "?" => FormatTrait::Debug, |
| "e" => FormatTrait::LowerExp, |
| "E" => FormatTrait::UpperExp, |
| "o" => FormatTrait::Octal, |
| "p" => FormatTrait::Pointer, |
| "b" => FormatTrait::Binary, |
| "x" => FormatTrait::LowerHex, |
| "X" => FormatTrait::UpperHex, |
| _ => { |
| invalid_placeholder_type_error(ecx, format.ty, format.ty_span, fmt_span); |
| FormatTrait::Display |
| } |
| }; |
| |
| let precision_span = format.precision_span.and_then(to_span); |
| let precision = match format.precision { |
| parse::CountIs(n) => Some(FormatCount::Literal(n)), |
| parse::CountIsName(name, name_span) => Some(FormatCount::Argument(lookup_arg( |
| Name(name, to_span(name_span)), |
| precision_span, |
| Precision, |
| FormatArgPositionKind::Named, |
| ))), |
| parse::CountIsParam(i) => Some(FormatCount::Argument(lookup_arg( |
| Index(i), |
| precision_span, |
| Precision, |
| FormatArgPositionKind::Number, |
| ))), |
| parse::CountIsStar(i) => Some(FormatCount::Argument(lookup_arg( |
| Index(i), |
| precision_span, |
| Precision, |
| FormatArgPositionKind::Implicit, |
| ))), |
| parse::CountImplied => None, |
| }; |
| |
| let width_span = format.width_span.and_then(to_span); |
| let width = match format.width { |
| parse::CountIs(n) => Some(FormatCount::Literal(n)), |
| parse::CountIsName(name, name_span) => Some(FormatCount::Argument(lookup_arg( |
| Name(name, to_span(name_span)), |
| width_span, |
| Width, |
| FormatArgPositionKind::Named, |
| ))), |
| parse::CountIsParam(i) => Some(FormatCount::Argument(lookup_arg( |
| Index(i), |
| width_span, |
| Width, |
| FormatArgPositionKind::Number, |
| ))), |
| parse::CountIsStar(_) => unreachable!(), |
| parse::CountImplied => None, |
| }; |
| |
| template.push(FormatArgsPiece::Placeholder(FormatPlaceholder { |
| argument, |
| span, |
| format_trait, |
| format_options: FormatOptions { |
| fill: format.fill, |
| alignment, |
| sign: format.sign.map(|s| match s { |
| parse::Sign::Plus => FormatSign::Plus, |
| parse::Sign::Minus => FormatSign::Minus, |
| }), |
| alternate: format.alternate, |
| zero_pad: format.zero_pad, |
| debug_hex: format.debug_hex.map(|s| match s { |
| parse::DebugHex::Lower => FormatDebugHex::Lower, |
| parse::DebugHex::Upper => FormatDebugHex::Upper, |
| }), |
| precision, |
| width, |
| }, |
| })); |
| } |
| } |
| } |
| |
| if !unfinished_literal.is_empty() { |
| template.push(FormatArgsPiece::Literal(Symbol::intern(&unfinished_literal))); |
| } |
| |
| if !invalid_refs.is_empty() { |
| report_invalid_references(ecx, &invalid_refs, &template, fmt_span, &args, parser); |
| } |
| |
| let unused = used |
| .iter() |
| .enumerate() |
| .filter(|&(_, used)| !used) |
| .map(|(i, _)| { |
| let named = matches!(args.explicit_args()[i].kind, FormatArgumentKind::Named(_)); |
| (args.explicit_args()[i].expr.span, named) |
| }) |
| .collect::<Vec<_>>(); |
| |
| let has_unused = !unused.is_empty(); |
| if has_unused { |
| // If there's a lot of unused arguments, |
| // let's check if this format arguments looks like another syntax (printf / shell). |
| let detect_foreign_fmt = unused.len() > args.explicit_args().len() / 2; |
| report_missing_placeholders( |
| ecx, |
| unused, |
| &used, |
| &args, |
| &pieces, |
| detect_foreign_fmt, |
| str_style, |
| fmt_str, |
| fmt_span, |
| ); |
| } |
| |
| // Only check for unused named argument names if there are no other errors to avoid causing |
| // too much noise in output errors, such as when a named argument is entirely unused. |
| if invalid_refs.is_empty() && !has_unused && !unnamed_arg_after_named_arg { |
| for &(index, span, used_as) in &numeric_references_to_named_arg { |
| let (position_sp_to_replace, position_sp_for_msg) = match used_as { |
| Placeholder(pspan) => (span, pspan), |
| Precision => { |
| // Strip the leading `.` for precision. |
| let span = span.map(|span| span.with_lo(span.lo() + BytePos(1))); |
| (span, span) |
| } |
| Width => (span, span), |
| }; |
| let arg_name = args.explicit_args()[index].kind.ident().unwrap(); |
| ecx.buffered_early_lint.push(BufferedEarlyLint { |
| span: Some(arg_name.span.into()), |
| node_id: rustc_ast::CRATE_NODE_ID, |
| lint_id: LintId::of(NAMED_ARGUMENTS_USED_POSITIONALLY), |
| diagnostic: BuiltinLintDiag::NamedArgumentUsedPositionally { |
| position_sp_to_replace, |
| position_sp_for_msg, |
| named_arg_sp: arg_name.span, |
| named_arg_name: arg_name.name.to_string(), |
| is_formatting_arg: matches!(used_as, Width | Precision), |
| }, |
| }); |
| } |
| } |
| |
| ExpandResult::Ready(Ok(FormatArgs { |
| span: fmt_span, |
| template, |
| arguments: args, |
| uncooked_fmt_str, |
| is_source_literal, |
| })) |
| } |
| |
| fn invalid_placeholder_type_error( |
| ecx: &ExtCtxt<'_>, |
| ty: &str, |
| ty_span: Option<Range<usize>>, |
| fmt_span: Span, |
| ) { |
| let sp = ty_span.map(|sp| fmt_span.from_inner(InnerSpan::new(sp.start, sp.end))); |
| let suggs = if let Some(sp) = sp { |
| [ |
| ("", "Display"), |
| ("?", "Debug"), |
| ("e", "LowerExp"), |
| ("E", "UpperExp"), |
| ("o", "Octal"), |
| ("p", "Pointer"), |
| ("b", "Binary"), |
| ("x", "LowerHex"), |
| ("X", "UpperHex"), |
| ] |
| .into_iter() |
| .map(|(fmt, trait_name)| errors::FormatUnknownTraitSugg { span: sp, fmt, trait_name }) |
| .collect() |
| } else { |
| vec![] |
| }; |
| ecx.dcx().emit_err(errors::FormatUnknownTrait { span: sp.unwrap_or(fmt_span), ty, suggs }); |
| } |
| |
| fn report_missing_placeholders( |
| ecx: &ExtCtxt<'_>, |
| unused: Vec<(Span, bool)>, |
| used: &[bool], |
| args: &FormatArguments, |
| pieces: &[parse::Piece<'_>], |
| detect_foreign_fmt: bool, |
| str_style: Option<usize>, |
| fmt_str: &str, |
| fmt_span: Span, |
| ) { |
| let mut diag = if let &[(span, named)] = &unused[..] { |
| ecx.dcx().create_err(errors::FormatUnusedArg { span, named }) |
| } else { |
| let unused_labels = |
| unused.iter().map(|&(span, named)| errors::FormatUnusedArg { span, named }).collect(); |
| let unused_spans = unused.iter().map(|&(span, _)| span).collect(); |
| ecx.dcx().create_err(errors::FormatUnusedArgs { |
| fmt: fmt_span, |
| unused: unused_spans, |
| unused_labels, |
| }) |
| }; |
| |
| let placeholders = pieces |
| .iter() |
| .filter_map(|piece| { |
| if let parse::Piece::NextArgument(argument) = piece |
| && let ArgumentNamed(binding) = argument.position |
| { |
| let span = fmt_span.from_inner(InnerSpan::new( |
| argument.position_span.start, |
| argument.position_span.end, |
| )); |
| Some((span, binding)) |
| } else { |
| None |
| } |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !placeholders.is_empty() { |
| if let Some(new_diag) = report_redundant_format_arguments(ecx, args, used, placeholders) { |
| diag.cancel(); |
| new_diag.emit(); |
| return; |
| } |
| } |
| |
| // Used to ensure we only report translations for *one* kind of foreign format. |
| let mut found_foreign = false; |
| |
| // Decide if we want to look for foreign formatting directives. |
| if detect_foreign_fmt { |
| use super::format_foreign as foreign; |
| |
| // The set of foreign substitutions we've explained. This prevents spamming the user |
| // with `%d should be written as {}` over and over again. |
| let mut explained = FxHashSet::default(); |
| |
| macro_rules! check_foreign { |
| ($kind:ident) => {{ |
| let mut show_doc_note = false; |
| |
| let mut suggestions = vec![]; |
| // account for `"` and account for raw strings `r#` |
| let padding = str_style.map(|i| i + 2).unwrap_or(1); |
| for sub in foreign::$kind::iter_subs(fmt_str, padding) { |
| let (trn, success) = match sub.translate() { |
| Ok(trn) => (trn, true), |
| Err(Some(msg)) => (msg, false), |
| |
| // If it has no translation, don't call it out specifically. |
| _ => continue, |
| }; |
| |
| let pos = sub.position(); |
| if !explained.insert(sub.to_string()) { |
| continue; |
| } |
| |
| if !found_foreign { |
| found_foreign = true; |
| show_doc_note = true; |
| } |
| |
| let sp = fmt_span.from_inner(pos); |
| |
| if success { |
| suggestions.push((sp, trn)); |
| } else { |
| diag.span_note( |
| sp, |
| format!("format specifiers use curly braces, and {}", trn), |
| ); |
| } |
| } |
| |
| if show_doc_note { |
| diag.note(concat!( |
| stringify!($kind), |
| " formatting is not supported; see the documentation for `std::fmt`", |
| )); |
| } |
| if suggestions.len() > 0 { |
| diag.multipart_suggestion( |
| "format specifiers use curly braces", |
| suggestions, |
| Applicability::MachineApplicable, |
| ); |
| } |
| }}; |
| } |
| |
| check_foreign!(printf); |
| if !found_foreign { |
| check_foreign!(shell); |
| } |
| } |
| if !found_foreign && unused.len() == 1 { |
| diag.span_label(fmt_span, "formatting specifier missing"); |
| } |
| |
| diag.emit(); |
| } |
| |
| /// This function detects and reports unused format!() arguments that are |
| /// redundant due to implicit captures (e.g. `format!("{x}", x)`). |
| fn report_redundant_format_arguments<'a>( |
| ecx: &ExtCtxt<'a>, |
| args: &FormatArguments, |
| used: &[bool], |
| placeholders: Vec<(Span, &str)>, |
| ) -> Option<Diag<'a>> { |
| let mut fmt_arg_indices = vec![]; |
| let mut args_spans = vec![]; |
| let mut fmt_spans = vec![]; |
| |
| for (i, unnamed_arg) in args.unnamed_args().iter().enumerate().rev() { |
| let Some(ty) = unnamed_arg.expr.to_ty() else { continue }; |
| let Some(argument_binding) = ty.kind.is_simple_path() else { continue }; |
| let argument_binding = argument_binding.as_str(); |
| |
| if used[i] { |
| continue; |
| } |
| |
| let matching_placeholders = placeholders |
| .iter() |
| .filter(|(_, inline_binding)| argument_binding == *inline_binding) |
| .map(|(span, _)| span) |
| .collect::<Vec<_>>(); |
| |
| if !matching_placeholders.is_empty() { |
| fmt_arg_indices.push(i); |
| args_spans.push(unnamed_arg.expr.span); |
| for span in &matching_placeholders { |
| if fmt_spans.contains(*span) { |
| continue; |
| } |
| fmt_spans.push(**span); |
| } |
| } |
| } |
| |
| if !args_spans.is_empty() { |
| let multispan = MultiSpan::from(fmt_spans); |
| let mut suggestion_spans = vec![]; |
| |
| for (arg_span, fmt_arg_idx) in args_spans.iter().zip(fmt_arg_indices.iter()) { |
| let span = if fmt_arg_idx + 1 == args.explicit_args().len() { |
| *arg_span |
| } else { |
| arg_span.until(args.explicit_args()[*fmt_arg_idx + 1].expr.span) |
| }; |
| |
| suggestion_spans.push(span); |
| } |
| |
| let sugg = if args.named_args().len() == 0 { |
| Some(errors::FormatRedundantArgsSugg { spans: suggestion_spans }) |
| } else { |
| None |
| }; |
| |
| return Some(ecx.dcx().create_err(errors::FormatRedundantArgs { |
| n: args_spans.len(), |
| span: MultiSpan::from(args_spans), |
| note: multispan, |
| sugg, |
| })); |
| } |
| |
| None |
| } |
| |
| /// Handle invalid references to positional arguments. Output different |
| /// errors for the case where all arguments are positional and for when |
| /// there are named arguments or numbered positional arguments in the |
| /// format string. |
| fn report_invalid_references( |
| ecx: &ExtCtxt<'_>, |
| invalid_refs: &[(usize, Option<Span>, PositionUsedAs, FormatArgPositionKind)], |
| template: &[FormatArgsPiece], |
| fmt_span: Span, |
| args: &FormatArguments, |
| parser: parse::Parser<'_>, |
| ) { |
| let num_args_desc = match args.explicit_args().len() { |
| 0 => "no arguments were given".to_string(), |
| 1 => "there is 1 argument".to_string(), |
| n => format!("there are {n} arguments"), |
| }; |
| |
| let mut e; |
| |
| if template.iter().all(|piece| match piece { |
| FormatArgsPiece::Placeholder(FormatPlaceholder { |
| argument: FormatArgPosition { kind: FormatArgPositionKind::Number, .. }, |
| .. |
| }) => false, |
| FormatArgsPiece::Placeholder(FormatPlaceholder { |
| format_options: |
| FormatOptions { |
| precision: |
| Some(FormatCount::Argument(FormatArgPosition { |
| kind: FormatArgPositionKind::Number, |
| .. |
| })), |
| .. |
| } |
| | FormatOptions { |
| width: |
| Some(FormatCount::Argument(FormatArgPosition { |
| kind: FormatArgPositionKind::Number, |
| .. |
| })), |
| .. |
| }, |
| .. |
| }) => false, |
| _ => true, |
| }) { |
| // There are no numeric positions. |
| // Collect all the implicit positions: |
| let mut spans = Vec::new(); |
| let mut num_placeholders = 0; |
| for piece in template { |
| let mut placeholder = None; |
| // `{arg:.*}` |
| if let FormatArgsPiece::Placeholder(FormatPlaceholder { |
| format_options: |
| FormatOptions { |
| precision: |
| Some(FormatCount::Argument(FormatArgPosition { |
| span, |
| kind: FormatArgPositionKind::Implicit, |
| .. |
| })), |
| .. |
| }, |
| .. |
| }) = piece |
| { |
| placeholder = *span; |
| num_placeholders += 1; |
| } |
| // `{}` |
| if let FormatArgsPiece::Placeholder(FormatPlaceholder { |
| argument: FormatArgPosition { kind: FormatArgPositionKind::Implicit, .. }, |
| span, |
| .. |
| }) = piece |
| { |
| placeholder = *span; |
| num_placeholders += 1; |
| } |
| // For `{:.*}`, we only push one span. |
| spans.extend(placeholder); |
| } |
| let span = if spans.is_empty() { |
| MultiSpan::from_span(fmt_span) |
| } else { |
| MultiSpan::from_spans(spans) |
| }; |
| e = ecx.dcx().create_err(errors::FormatPositionalMismatch { |
| span, |
| n: num_placeholders, |
| desc: num_args_desc, |
| highlight: SingleLabelManySpans { |
| spans: args.explicit_args().iter().map(|arg| arg.expr.span).collect(), |
| label: "", |
| }, |
| }); |
| // Point out `{:.*}` placeholders: those take an extra argument. |
| let mut has_precision_star = false; |
| for piece in template { |
| if let FormatArgsPiece::Placeholder(FormatPlaceholder { |
| format_options: |
| FormatOptions { |
| precision: |
| Some(FormatCount::Argument(FormatArgPosition { |
| index, |
| span: Some(span), |
| kind: FormatArgPositionKind::Implicit, |
| .. |
| })), |
| .. |
| }, |
| .. |
| }) = piece |
| { |
| let (Ok(index) | Err(index)) = index; |
| has_precision_star = true; |
| e.span_label( |
| *span, |
| format!( |
| "this precision flag adds an extra required argument at position {}, which is why there {} expected", |
| index, |
| if num_placeholders == 1 { |
| "is 1 argument".to_string() |
| } else { |
| format!("are {num_placeholders} arguments") |
| }, |
| ), |
| ); |
| } |
| } |
| if has_precision_star { |
| e.note("positional arguments are zero-based"); |
| } |
| } else { |
| let mut indexes: Vec<_> = invalid_refs.iter().map(|&(index, _, _, _)| index).collect(); |
| // Avoid `invalid reference to positional arguments 7 and 7 (there is 1 argument)` |
| // for `println!("{7:7$}", 1);` |
| indexes.sort(); |
| indexes.dedup(); |
| let span: MultiSpan = if !parser.is_source_literal || parser.arg_places.is_empty() { |
| MultiSpan::from_span(fmt_span) |
| } else { |
| MultiSpan::from_spans(invalid_refs.iter().filter_map(|&(_, span, _, _)| span).collect()) |
| }; |
| let arg_list = format!( |
| "argument{} {}", |
| pluralize!(indexes.len()), |
| listify(&indexes, |i: &usize| i.to_string()).unwrap_or_default() |
| ); |
| e = ecx.dcx().struct_span_err( |
| span, |
| format!("invalid reference to positional {arg_list} ({num_args_desc})"), |
| ); |
| e.note("positional arguments are zero-based"); |
| } |
| |
| if template.iter().any(|piece| match piece { |
| FormatArgsPiece::Placeholder(FormatPlaceholder { format_options: f, .. }) => { |
| *f != FormatOptions::default() |
| } |
| _ => false, |
| }) { |
| e.note("for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html"); |
| } |
| |
| e.emit(); |
| } |
| |
| fn expand_format_args_impl<'cx>( |
| ecx: &'cx mut ExtCtxt<'_>, |
| mut sp: Span, |
| tts: TokenStream, |
| nl: bool, |
| ) -> MacroExpanderResult<'cx> { |
| sp = ecx.with_def_site_ctxt(sp); |
| ExpandResult::Ready(match parse_args(ecx, sp, tts) { |
| Ok(input) => { |
| let ExpandResult::Ready(mac) = make_format_args(ecx, input, nl) else { |
| return ExpandResult::Retry(()); |
| }; |
| match mac { |
| Ok(format_args) => { |
| MacEager::expr(ecx.expr(sp, ExprKind::FormatArgs(P(format_args)))) |
| } |
| Err(guar) => MacEager::expr(DummyResult::raw_expr(sp, Some(guar))), |
| } |
| } |
| Err(err) => { |
| let guar = err.emit(); |
| DummyResult::any(sp, guar) |
| } |
| }) |
| } |
| |
| pub(crate) fn expand_format_args<'cx>( |
| ecx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: TokenStream, |
| ) -> MacroExpanderResult<'cx> { |
| expand_format_args_impl(ecx, sp, tts, false) |
| } |
| |
| pub(crate) fn expand_format_args_nl<'cx>( |
| ecx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: TokenStream, |
| ) -> MacroExpanderResult<'cx> { |
| expand_format_args_impl(ecx, sp, tts, true) |
| } |
