| use rustc_ast::ptr::P; |
| use rustc_ast::token; |
| use rustc_ast::tokenstream::TokenStream; |
| use rustc_ast::Expr; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_errors::{pluralize, Applicability, MultiSpan, PResult}; |
| use rustc_expand::base::{self, *}; |
| use rustc_parse_format as parse; |
| use rustc_span::symbol::{Ident, Symbol}; |
| use rustc_span::{BytePos, InnerSpan, Span}; |
| |
| use rustc_lint_defs::builtin::NAMED_ARGUMENTS_USED_POSITIONALLY; |
| use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiagnostics, LintId}; |
| |
| mod ast; |
| use ast::*; |
| |
| mod expand; |
| use expand::expand_parsed_format_args; |
| |
| // 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` structure. |
| // 3. Finally, `expand_parsed_format_args` will turn that `FormatArgs` structure |
| // into the expression that the macro expands to. |
| |
| // See format/ast.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::*; |
| |
| /// 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: &mut ExtCtxt<'a>, |
| sp: Span, |
| tts: TokenStream, |
| ) -> PResult<'a, (P<Expr>, FormatArguments)> { |
| let mut args = FormatArguments::new(); |
| |
| let mut p = ecx.new_parser_from_tts(tts); |
| |
| if p.token == token::Eof { |
| return Err(ecx.struct_span_err(sp, "requires at least a format string argument")); |
| } |
| |
| let first_token = &p.token; |
| let fmtstr = match first_token.kind { |
| token::TokenKind::Literal(token::Lit { |
| kind: token::LitKind::Str | token::LitKind::StrRaw(_), |
| .. |
| }) => { |
| // If the first token is a string literal, then a format expression |
| // is constructed from it. |
| // |
| // 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()? |
| } |
| _ => { |
| // Otherwise, we fall back to the expression parser. |
| p.parse_expr()? |
| } |
| }; |
| |
| let mut first = true; |
| |
| while p.token != token::Eof { |
| if !p.eat(&token::Comma) { |
| if first { |
| p.clear_expected_tokens(); |
| } |
| |
| match p.expect(&token::Comma) { |
| Err(mut err) => { |
| match token::TokenKind::Comma.similar_tokens() { |
| Some(tks) if tks.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(); |
| } |
| // Otherwise stop the parsing and return the error. |
| _ => return Err(err), |
| } |
| } |
| Ok(recovered) => { |
| assert!(recovered); |
| } |
| } |
| } |
| 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(&token::Eq)?; |
| let expr = p.parse_expr()?; |
| if let Some((_, prev)) = args.by_name(ident.name) { |
| ecx.struct_span_err( |
| ident.span, |
| &format!("duplicate argument named `{}`", ident), |
| ) |
| .span_label(prev.kind.ident().unwrap().span, "previously here") |
| .span_label(ident.span, "duplicate argument") |
| .emit(); |
| continue; |
| } |
| args.add(FormatArgument { kind: FormatArgumentKind::Named(ident), expr }); |
| } |
| _ => { |
| let expr = p.parse_expr()?; |
| if !args.named_args().is_empty() { |
| let mut err = ecx.struct_span_err( |
| expr.span, |
| "positional arguments cannot follow named arguments", |
| ); |
| err.span_label( |
| expr.span, |
| "positional arguments must be before named arguments", |
| ); |
| for arg in args.named_args() { |
| if let Some(name) = arg.kind.ident() { |
| err.span_label(name.span.to(arg.expr.span), "named argument"); |
| } |
| } |
| err.emit(); |
| } |
| args.add(FormatArgument { kind: FormatArgumentKind::Normal, expr }); |
| } |
| } |
| } |
| Ok((fmtstr, args)) |
| } |
| |
| pub fn make_format_args( |
| ecx: &mut ExtCtxt<'_>, |
| efmt: P<Expr>, |
| mut args: FormatArguments, |
| append_newline: bool, |
| ) -> Result<FormatArgs, ()> { |
| let msg = "format argument must be a string literal"; |
| let unexpanded_fmt_span = efmt.span; |
| let (fmt_str, fmt_style, fmt_span) = match expr_to_spanned_string(ecx, efmt, msg) { |
| Ok(mut fmt) if append_newline => { |
| fmt.0 = Symbol::intern(&format!("{}\n", fmt.0)); |
| fmt |
| } |
| Ok(fmt) => fmt, |
| Err(err) => { |
| if let Some((mut err, suggested)) = err { |
| let sugg_fmt = match args.explicit_args().len() { |
| 0 => "{}".to_string(), |
| _ => format!("{}{{}}", "{} ".repeat(args.explicit_args().len())), |
| }; |
| if !suggested { |
| 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(); |
| } |
| return Err(()); |
| } |
| }; |
| |
| 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_literal = parser.is_literal; |
| |
| if !parser.errors.is_empty() { |
| let err = parser.errors.remove(0); |
| let sp = if is_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 = ecx.struct_span_err(sp, &format!("invalid format string: {}", err.description)); |
| e.span_label(sp, err.label + " in format string"); |
| if let Some(note) = err.note { |
| e.note(¬e); |
| } |
| if let Some((label, span)) = err.secondary_label && is_literal { |
| e.span_label(fmt_span.from_inner(InnerSpan::new(span.start, span.end)), label); |
| } |
| if err.should_be_replaced_with_positional_argument { |
| 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.multipart_suggestion_verbose( |
| "consider using a positional formatting argument instead", |
| vec![ |
| (captured_arg_span, args.unnamed_args().len().to_string()), |
| (span.shrink_to_hi(), format!(", {}", arg)), |
| ], |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| e.emit(); |
| return Err(()); |
| } |
| |
| let to_span = |inner_span: rustc_parse_format::InnerSpan| { |
| is_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_refences_to_named_arg = Vec::new(); |
| |
| enum ArgRef<'a> { |
| Index(usize), |
| Name(&'a str, Option<Span>), |
| } |
| use ArgRef::*; |
| |
| 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_refences_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_literal { |
| ecx.expr_ident(span, ident) |
| } else { |
| // For the moment capturing variables from format strings expanded from macros is |
| // disabled (see RFC #2795) |
| ecx.struct_span_err(span, &format!("there is no argument named `{name}`")) |
| .note(format!("did you intend to capture a variable `{name}` from the surrounding scope?")) |
| .note("to avoid ambiguity, `format_args!` cannot capture variables when the format string is expanded from a macro") |
| .emit(); |
| DummyResult::raw_expr(span, true) |
| }; |
| 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 { |
| parse::Piece::String(s) => { |
| unfinished_literal.push_str(s); |
| } |
| parse::Piece::NextArgument(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)); |
| 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, |
| flags: format.flags, |
| 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 msg = if let FormatArgumentKind::Named(_) = args.explicit_args()[i].kind { |
| "named argument never used" |
| } else { |
| "argument never used" |
| }; |
| (args.explicit_args()[i].expr.span, msg) |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !unused.is_empty() { |
| // 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, 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() && ecx.sess.err_count() == 0 { |
| for &(index, span, used_as) in &numeric_refences_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: arg_name.span.into(), |
| msg: format!("named argument `{}` is not used by name", arg_name.name).into(), |
| node_id: rustc_ast::CRATE_NODE_ID, |
| lint_id: LintId::of(&NAMED_ARGUMENTS_USED_POSITIONALLY), |
| diagnostic: BuiltinLintDiagnostics::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), |
| }, |
| }); |
| } |
| } |
| |
| Ok(FormatArgs { span: fmt_span, template, arguments: args }) |
| } |
| |
| fn invalid_placeholder_type_error( |
| ecx: &ExtCtxt<'_>, |
| ty: &str, |
| ty_span: Option<rustc_parse_format::InnerSpan>, |
| fmt_span: Span, |
| ) { |
| let sp = ty_span.map(|sp| fmt_span.from_inner(InnerSpan::new(sp.start, sp.end))); |
| let mut err = |
| ecx.struct_span_err(sp.unwrap_or(fmt_span), &format!("unknown format trait `{}`", ty)); |
| err.note( |
| "the only appropriate formatting traits are:\n\ |
| - ``, which uses the `Display` trait\n\ |
| - `?`, which uses the `Debug` trait\n\ |
| - `e`, which uses the `LowerExp` trait\n\ |
| - `E`, which uses the `UpperExp` trait\n\ |
| - `o`, which uses the `Octal` trait\n\ |
| - `p`, which uses the `Pointer` trait\n\ |
| - `b`, which uses the `Binary` trait\n\ |
| - `x`, which uses the `LowerHex` trait\n\ |
| - `X`, which uses the `UpperHex` trait", |
| ); |
| if let Some(sp) = sp { |
| for (fmt, name) in &[ |
| ("", "Display"), |
| ("?", "Debug"), |
| ("e", "LowerExp"), |
| ("E", "UpperExp"), |
| ("o", "Octal"), |
| ("p", "Pointer"), |
| ("b", "Binary"), |
| ("x", "LowerHex"), |
| ("X", "UpperHex"), |
| ] { |
| err.tool_only_span_suggestion( |
| sp, |
| &format!("use the `{}` trait", name), |
| *fmt, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| err.emit(); |
| } |
| |
| fn report_missing_placeholders( |
| ecx: &mut ExtCtxt<'_>, |
| unused: Vec<(Span, &str)>, |
| detect_foreign_fmt: bool, |
| str_style: Option<usize>, |
| fmt_str: &str, |
| fmt_span: Span, |
| ) { |
| let mut diag = if let &[(span, msg)] = &unused[..] { |
| let mut diag = ecx.struct_span_err(span, msg); |
| diag.span_label(span, msg); |
| diag |
| } else { |
| let mut diag = ecx.struct_span_err( |
| unused.iter().map(|&(sp, _)| sp).collect::<Vec<Span>>(), |
| "multiple unused formatting arguments", |
| ); |
| diag.span_label(fmt_span, "multiple missing formatting specifiers"); |
| for &(span, msg) in &unused { |
| diag.span_label(span, msg); |
| } |
| diag |
| }; |
| |
| // 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(); |
| let sub = String::from(sub.as_str()); |
| if explained.contains(&sub) { |
| continue; |
| } |
| explained.insert(sub.clone()); |
| |
| if !found_foreign { |
| found_foreign = true; |
| show_doc_note = true; |
| } |
| |
| if let Some(inner_sp) = pos { |
| let sp = fmt_span.from_inner(inner_sp); |
| |
| if success { |
| suggestions.push((sp, trn)); |
| } else { |
| diag.span_note( |
| sp, |
| &format!("format specifiers use curly braces, and {}", trn), |
| ); |
| } |
| } else { |
| if success { |
| diag.help(&format!("`{}` should be written as `{}`", sub, trn)); |
| } else { |
| diag.note(&format!("`{}` should use curly braces, and {}", sub, trn)); |
| } |
| } |
| } |
| |
| if show_doc_note { |
| diag.note(concat!( |
| stringify!($kind), |
| " formatting 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(); |
| } |
| |
| /// 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: &mut 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 {} arguments", n), |
| }; |
| |
| 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.struct_span_err( |
| span, |
| &format!( |
| "{} positional argument{} in format string, but {}", |
| num_placeholders, |
| pluralize!(num_placeholders), |
| num_args_desc, |
| ), |
| ); |
| for arg in args.explicit_args() { |
| e.span_label(arg.expr.span, ""); |
| } |
| // 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 {} arguments", num_placeholders) |
| }, |
| ), |
| ); |
| } |
| } |
| 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_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 = if let &[index] = &indexes[..] { |
| format!("argument {index}") |
| } else { |
| let tail = indexes.pop().unwrap(); |
| format!( |
| "arguments {head} and {tail}", |
| head = indexes.into_iter().map(|i| i.to_string()).collect::<Vec<_>>().join(", ") |
| ) |
| }; |
| e = ecx.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, |
| ) -> Box<dyn base::MacResult + 'cx> { |
| sp = ecx.with_def_site_ctxt(sp); |
| match parse_args(ecx, sp, tts) { |
| Ok((efmt, args)) => { |
| if let Ok(format_args) = make_format_args(ecx, efmt, args, nl) { |
| MacEager::expr(expand_parsed_format_args(ecx, format_args)) |
| } else { |
| MacEager::expr(DummyResult::raw_expr(sp, true)) |
| } |
| } |
| Err(mut err) => { |
| err.emit(); |
| DummyResult::any(sp) |
| } |
| } |
| } |
| |
| pub fn expand_format_args<'cx>( |
| ecx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: TokenStream, |
| ) -> Box<dyn base::MacResult + 'cx> { |
| expand_format_args_impl(ecx, sp, tts, false) |
| } |
| |
| pub fn expand_format_args_nl<'cx>( |
| ecx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: TokenStream, |
| ) -> Box<dyn base::MacResult + 'cx> { |
| expand_format_args_impl(ecx, sp, tts, true) |
| } |
