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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /compiler/rustc_builtin_macros/src/format.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_builtin_macros/src/format.rs | 1573 |
1 files changed, 1573 insertions, 0 deletions
diff --git a/compiler/rustc_builtin_macros/src/format.rs b/compiler/rustc_builtin_macros/src/format.rs new file mode 100644 index 000000000..9eb96ec76 --- /dev/null +++ b/compiler/rustc_builtin_macros/src/format.rs @@ -0,0 +1,1573 @@ +use ArgumentType::*; +use Position::*; + +use rustc_ast as ast; +use rustc_ast::ptr::P; +use rustc_ast::tokenstream::TokenStream; +use rustc_ast::visit::{self, Visitor}; +use rustc_ast::{token, BlockCheckMode, UnsafeSource}; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_errors::{pluralize, Applicability, MultiSpan, PResult}; +use rustc_expand::base::{self, *}; +use rustc_parse_format as parse; +use rustc_span::symbol::{sym, Ident, Symbol}; +use rustc_span::{BytePos, InnerSpan, Span}; +use smallvec::SmallVec; + +use rustc_lint_defs::builtin::NAMED_ARGUMENTS_USED_POSITIONALLY; +use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiagnostics, LintId}; +use rustc_parse_format::Count; +use std::borrow::Cow; +use std::collections::hash_map::Entry; + +#[derive(PartialEq)] +enum ArgumentType { + Placeholder(&'static str), + Count, +} + +enum Position { + Exact(usize), + Capture(usize), + Named(Symbol, InnerSpan), +} + +/// Indicates how positional named argument (i.e. an named argument which is used by position +/// instead of by name) is used in format string +/// * `Arg` is the actual argument to print +/// * `Width` is width format argument +/// * `Precision` is precion format argument +/// Example: `{Arg:Width$.Precision$} +#[derive(Debug, Eq, PartialEq)] +enum PositionalNamedArgType { + Arg, + Width, + Precision, +} + +/// Contains information necessary to create a lint for a positional named argument +#[derive(Debug)] +struct PositionalNamedArg { + ty: PositionalNamedArgType, + /// The piece of the using this argument (multiple pieces can use the same argument) + cur_piece: usize, + /// The InnerSpan for in the string to be replaced with the named argument + /// This will be None when the position is implicit + inner_span_to_replace: Option<rustc_parse_format::InnerSpan>, + /// The name to use instead of the position + replacement: Symbol, + /// The span for the positional named argument (so the lint can point a message to it) + positional_named_arg_span: Span, + has_formatting: bool, +} + +impl PositionalNamedArg { + /// Determines: + /// 1) span to be replaced with the name of the named argument and + /// 2) span to be underlined for error messages + fn get_positional_arg_spans(&self, cx: &Context<'_, '_>) -> (Option<Span>, Option<Span>) { + if let Some(inner_span) = &self.inner_span_to_replace { + let span = + cx.fmtsp.from_inner(InnerSpan { start: inner_span.start, end: inner_span.end }); + (Some(span), Some(span)) + } else if self.ty == PositionalNamedArgType::Arg { + // In the case of a named argument whose position is implicit, if the argument *has* + // formatting, there will not be a span to replace. Instead, we insert the name after + // the `{`, which will be the first character of arg_span. If the argument does *not* + // have formatting, there may or may not be a span to replace. This is because + // whitespace is allowed in arguments without formatting (such as `format!("{ }", 1);`) + // but is not allowed in arguments with formatting (an error will be generated in cases + // like `format!("{ :1.1}", 1.0f32);`. + // For the message span, if there is formatting, we want to use the opening `{` and the + // next character, which will the `:` indicating the start of formatting. If there is + // not any formatting, we want to underline the entire span. + cx.arg_spans.get(self.cur_piece).map_or((None, None), |arg_span| { + if self.has_formatting { + ( + Some(arg_span.with_lo(arg_span.lo() + BytePos(1)).shrink_to_lo()), + Some(arg_span.with_hi(arg_span.lo() + BytePos(2))), + ) + } else { + let replace_start = arg_span.lo() + BytePos(1); + let replace_end = arg_span.hi() - BytePos(1); + let to_replace = arg_span.with_lo(replace_start).with_hi(replace_end); + (Some(to_replace), Some(*arg_span)) + } + }) + } else { + (None, None) + } + } +} + +/// Encapsulates all the named arguments that have been used positionally +#[derive(Debug)] +struct PositionalNamedArgsLint { + positional_named_args: Vec<PositionalNamedArg>, +} + +impl PositionalNamedArgsLint { + /// For a given positional argument, check if the index is for a named argument. + /// + /// Since positional arguments are required to come before named arguments, if the positional + /// index is greater than or equal to the start of named arguments, we know it's a named + /// argument used positionally. + /// + /// Example: + /// println!("{} {} {2}", 0, a=1, b=2); + /// + /// In this case, the first piece (`{}`) would be ArgumentImplicitlyIs with an index of 0. The + /// total number of arguments is 3 and the number of named arguments is 2, so the start of named + /// arguments is index 1. Therefore, the index of 0 is okay. + /// + /// The second piece (`{}`) would be ArgumentImplicitlyIs with an index of 1, which is the start + /// of named arguments, and so we should add a lint to use the named argument `a`. + /// + /// The third piece (`{2}`) would be ArgumentIs with an index of 2, which is greater than the + /// start of named arguments, and so we should add a lint to use the named argument `b`. + /// + /// This same check also works for width and precision formatting when either or both are + /// CountIsParam, which contains an index into the arguments. + fn maybe_add_positional_named_arg( + &mut self, + current_positional_arg: usize, + total_args_length: usize, + format_argument_index: usize, + ty: PositionalNamedArgType, + cur_piece: usize, + inner_span_to_replace: Option<rustc_parse_format::InnerSpan>, + names: &FxHashMap<Symbol, (usize, Span)>, + has_formatting: bool, + ) { + let start_of_named_args = total_args_length - names.len(); + if current_positional_arg >= start_of_named_args { + self.maybe_push( + format_argument_index, + ty, + cur_piece, + inner_span_to_replace, + names, + has_formatting, + ) + } + } + + /// Try constructing a PositionalNamedArg struct and pushing it into the vec of positional + /// named arguments. If a named arg associated with `format_argument_index` cannot be found, + /// a new item will not be added as the lint cannot be emitted in this case. + fn maybe_push( + &mut self, + format_argument_index: usize, + ty: PositionalNamedArgType, + cur_piece: usize, + inner_span_to_replace: Option<rustc_parse_format::InnerSpan>, + names: &FxHashMap<Symbol, (usize, Span)>, + has_formatting: bool, + ) { + let named_arg = names + .iter() + .find(|&(_, &(index, _))| index == format_argument_index) + .map(|found| found.clone()); + + if let Some((&replacement, &(_, positional_named_arg_span))) = named_arg { + // In FormatSpec, `precision_span` starts at the leading `.`, which we want to keep in + // the lint suggestion, so increment `start` by 1 when `PositionalArgumentType` is + // `Precision`. + let inner_span_to_replace = if ty == PositionalNamedArgType::Precision { + inner_span_to_replace + .map(|is| rustc_parse_format::InnerSpan { start: is.start + 1, end: is.end }) + } else { + inner_span_to_replace + }; + self.positional_named_args.push(PositionalNamedArg { + ty, + cur_piece, + inner_span_to_replace, + replacement, + positional_named_arg_span, + has_formatting, + }); + } + } +} + +struct Context<'a, 'b> { + ecx: &'a mut ExtCtxt<'b>, + /// The macro's call site. References to unstable formatting internals must + /// use this span to pass the stability checker. + macsp: Span, + /// The span of the format string literal. + fmtsp: Span, + + /// List of parsed argument expressions. + /// Named expressions are resolved early, and are appended to the end of + /// argument expressions. + /// + /// Example showing the various data structures in motion: + /// + /// * Original: `"{foo:o} {:o} {foo:x} {0:x} {1:o} {:x} {1:x} {0:o}"` + /// * Implicit argument resolution: `"{foo:o} {0:o} {foo:x} {0:x} {1:o} {1:x} {1:x} {0:o}"` + /// * Name resolution: `"{2:o} {0:o} {2:x} {0:x} {1:o} {1:x} {1:x} {0:o}"` + /// * `arg_types` (in JSON): `[[0, 1, 0], [0, 1, 1], [0, 1]]` + /// * `arg_unique_types` (in simplified JSON): `[["o", "x"], ["o", "x"], ["o", "x"]]` + /// * `names` (in JSON): `{"foo": 2}` + args: Vec<P<ast::Expr>>, + /// The number of arguments that were added by implicit capturing. + num_captured_args: usize, + /// Placeholder slot numbers indexed by argument. + arg_types: Vec<Vec<usize>>, + /// Unique format specs seen for each argument. + arg_unique_types: Vec<Vec<ArgumentType>>, + /// Map from named arguments to their resolved indices. + names: FxHashMap<Symbol, (usize, Span)>, + + /// The latest consecutive literal strings, or empty if there weren't any. + literal: String, + + /// Collection of the compiled `rt::Argument` structures + pieces: Vec<P<ast::Expr>>, + /// Collection of string literals + str_pieces: Vec<P<ast::Expr>>, + /// Stays `true` if all formatting parameters are default (as in "{}{}"). + all_pieces_simple: bool, + + /// Mapping between positional argument references and indices into the + /// final generated static argument array. We record the starting indices + /// corresponding to each positional argument, and number of references + /// consumed so far for each argument, to facilitate correct `Position` + /// mapping in `build_piece`. In effect this can be seen as a "flattened" + /// version of `arg_unique_types`. + /// + /// Again with the example described above in docstring for `args`: + /// + /// * `arg_index_map` (in JSON): `[[0, 1, 0], [2, 3, 3], [4, 5]]` + arg_index_map: Vec<Vec<usize>>, + + /// Starting offset of count argument slots. + count_args_index_offset: usize, + + /// Count argument slots and tracking data structures. + /// Count arguments are separately tracked for de-duplication in case + /// multiple references are made to one argument. For example, in this + /// format string: + /// + /// * Original: `"{:.*} {:.foo$} {1:.*} {:.0$}"` + /// * Implicit argument resolution: `"{1:.0$} {2:.foo$} {1:.3$} {4:.0$}"` + /// * Name resolution: `"{1:.0$} {2:.5$} {1:.3$} {4:.0$}"` + /// * `count_positions` (in JSON): `{0: 0, 5: 1, 3: 2}` + /// * `count_args`: `vec![0, 5, 3]` + count_args: Vec<usize>, + /// Relative slot numbers for count arguments. + count_positions: FxHashMap<usize, usize>, + /// Number of count slots assigned. + count_positions_count: usize, + + /// Current position of the implicit positional arg pointer, as if it + /// still existed in this phase of processing. + /// Used only for `all_pieces_simple` tracking in `build_piece`. + curarg: usize, + /// Current piece being evaluated, used for error reporting. + curpiece: usize, + /// Keep track of invalid references to positional arguments. + invalid_refs: Vec<(usize, usize)>, + /// Spans of all the formatting arguments, in order. + arg_spans: Vec<Span>, + /// All the formatting arguments that have formatting flags set, in order for diagnostics. + arg_with_formatting: Vec<parse::FormatSpec<'a>>, + + /// Whether this format string came from a string literal, as opposed to a macro. + is_literal: bool, + unused_names_lint: PositionalNamedArgsLint, +} + +pub struct FormatArg { + expr: P<ast::Expr>, + named: 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 +/// Some((fmtstr, parsed arguments, index map for named arguments)) +/// ``` +fn parse_args<'a>( + ecx: &mut ExtCtxt<'a>, + sp: Span, + tts: TokenStream, +) -> PResult<'a, (P<ast::Expr>, Vec<FormatArg>, FxHashMap<Symbol, (usize, Span)>)> { + let mut args = Vec::<FormatArg>::new(); + let mut names = FxHashMap::<Symbol, (usize, Span)>::default(); + + 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; + let mut named = false; + + 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) => { + named = true; + p.bump(); + p.expect(&token::Eq)?; + let e = p.parse_expr()?; + if let Some((prev, _)) = names.get(&ident.name) { + ecx.struct_span_err(e.span, &format!("duplicate argument named `{}`", ident)) + .span_label(args[*prev].expr.span, "previously here") + .span_label(e.span, "duplicate argument") + .emit(); + continue; + } + + // Resolve names into slots early. + // Since all the positional args are already seen at this point + // if the input is valid, we can simply append to the positional + // args. And remember the names. + let slot = args.len(); + names.insert(ident.name, (slot, ident.span)); + args.push(FormatArg { expr: e, named: true }); + } + _ => { + let e = p.parse_expr()?; + if named { + let mut err = ecx.struct_span_err( + e.span, + "positional arguments cannot follow named arguments", + ); + err.span_label(e.span, "positional arguments must be before named arguments"); + for pos in names.values() { + err.span_label(args[pos.0].expr.span, "named argument"); + } + err.emit(); + } + args.push(FormatArg { expr: e, named: false }); + } + } + } + Ok((fmtstr, args, names)) +} + +impl<'a, 'b> Context<'a, 'b> { + /// The number of arguments that were explicitly given. + fn num_args(&self) -> usize { + self.args.len() - self.num_captured_args + } + + fn resolve_name_inplace(&mut self, p: &mut parse::Piece<'_>) { + // NOTE: the `unwrap_or` branch is needed in case of invalid format + // arguments, e.g., `format_args!("{foo}")`. + let lookup = + |s: &str| self.names.get(&Symbol::intern(s)).unwrap_or(&(0, Span::default())).0; + + match *p { + parse::String(_) => {} + parse::NextArgument(ref mut arg) => { + if let parse::ArgumentNamed(s) = arg.position { + arg.position = parse::ArgumentIs(lookup(s)); + } + if let parse::CountIsName(s, _) = arg.format.width { + arg.format.width = parse::CountIsParam(lookup(s)); + } + if let parse::CountIsName(s, _) = arg.format.precision { + arg.format.precision = parse::CountIsParam(lookup(s)); + } + } + } + } + + /// Verifies one piece of a parse string, and remembers it if valid. + /// All errors are not emitted as fatal so we can continue giving errors + /// about this and possibly other format strings. + fn verify_piece(&mut self, p: &parse::Piece<'_>) { + match *p { + parse::String(..) => {} + parse::NextArgument(ref arg) => { + // width/precision first, if they have implicit positional + // parameters it makes more sense to consume them first. + self.verify_count( + arg.format.width, + &arg.format.width_span, + PositionalNamedArgType::Width, + ); + self.verify_count( + arg.format.precision, + &arg.format.precision_span, + PositionalNamedArgType::Precision, + ); + + let has_precision = arg.format.precision != Count::CountImplied; + let has_width = arg.format.width != Count::CountImplied; + + // argument second, if it's an implicit positional parameter + // it's written second, so it should come after width/precision. + let pos = match arg.position { + parse::ArgumentIs(i) => { + self.unused_names_lint.maybe_add_positional_named_arg( + i, + self.args.len(), + i, + PositionalNamedArgType::Arg, + self.curpiece, + Some(arg.position_span), + &self.names, + has_precision || has_width, + ); + + Exact(i) + } + parse::ArgumentImplicitlyIs(i) => { + self.unused_names_lint.maybe_add_positional_named_arg( + i, + self.args.len(), + i, + PositionalNamedArgType::Arg, + self.curpiece, + None, + &self.names, + has_precision || has_width, + ); + Exact(i) + } + parse::ArgumentNamed(s) => { + let symbol = Symbol::intern(s); + let span = arg.position_span; + Named(symbol, InnerSpan::new(span.start, span.end)) + } + }; + + let ty = Placeholder(match arg.format.ty { + "" => "Display", + "?" => "Debug", + "e" => "LowerExp", + "E" => "UpperExp", + "o" => "Octal", + "p" => "Pointer", + "b" => "Binary", + "x" => "LowerHex", + "X" => "UpperHex", + _ => { + let fmtsp = self.fmtsp; + let sp = arg + .format + .ty_span + .map(|sp| fmtsp.from_inner(InnerSpan::new(sp.start, sp.end))); + let mut err = self.ecx.struct_span_err( + sp.unwrap_or(fmtsp), + &format!("unknown format trait `{}`", arg.format.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"), + ] { + // FIXME: rustfix (`run-rustfix`) fails to apply suggestions. + // > "Cannot replace slice of data that was already replaced" + err.tool_only_span_suggestion( + sp, + &format!("use the `{}` trait", name), + *fmt, + Applicability::MaybeIncorrect, + ); + } + } + err.emit(); + "<invalid>" + } + }); + self.verify_arg_type(pos, ty); + self.curpiece += 1; + } + } + } + + fn verify_count( + &mut self, + c: parse::Count<'_>, + inner_span: &Option<rustc_parse_format::InnerSpan>, + named_arg_type: PositionalNamedArgType, + ) { + match c { + parse::CountImplied | parse::CountIs(..) => {} + parse::CountIsParam(i) => { + self.unused_names_lint.maybe_add_positional_named_arg( + i, + self.args.len(), + i, + named_arg_type, + self.curpiece, + *inner_span, + &self.names, + true, + ); + self.verify_arg_type(Exact(i), Count); + } + parse::CountIsName(s, span) => { + self.verify_arg_type( + Named(Symbol::intern(s), InnerSpan::new(span.start, span.end)), + Count, + ); + } + } + } + + fn describe_num_args(&self) -> Cow<'_, str> { + match self.num_args() { + 0 => "no arguments were given".into(), + 1 => "there is 1 argument".into(), + x => format!("there are {} arguments", x).into(), + } + } + + /// 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(&self, numbered_position_args: bool) { + let mut e; + let sp = if !self.arg_spans.is_empty() { + // Point at the formatting arguments. + MultiSpan::from_spans(self.arg_spans.clone()) + } else { + MultiSpan::from_span(self.fmtsp) + }; + let refs = + self.invalid_refs.iter().map(|(r, pos)| (r.to_string(), self.arg_spans.get(*pos))); + + let mut zero_based_note = false; + + let count = self.pieces.len() + + self.arg_with_formatting.iter().filter(|fmt| fmt.precision_span.is_some()).count(); + if self.names.is_empty() && !numbered_position_args && count != self.num_args() { + e = self.ecx.struct_span_err( + sp, + &format!( + "{} positional argument{} in format string, but {}", + count, + pluralize!(count), + self.describe_num_args(), + ), + ); + for arg in &self.args { + // Point at the arguments that will be formatted. + e.span_label(arg.span, ""); + } + } else { + let (mut refs, spans): (Vec<_>, Vec<_>) = refs.unzip(); + // Avoid `invalid reference to positional arguments 7 and 7 (there is 1 argument)` + // for `println!("{7:7$}", 1);` + refs.sort(); + refs.dedup(); + let spans: Vec<_> = spans.into_iter().filter_map(|sp| sp.copied()).collect(); + let sp = if self.arg_spans.is_empty() || spans.is_empty() { + MultiSpan::from_span(self.fmtsp) + } else { + MultiSpan::from_spans(spans) + }; + let arg_list = if refs.len() == 1 { + format!("argument {}", refs[0]) + } else { + let reg = refs.pop().unwrap(); + format!("arguments {head} and {tail}", head = refs.join(", "), tail = reg) + }; + + e = self.ecx.struct_span_err( + sp, + &format!( + "invalid reference to positional {} ({})", + arg_list, + self.describe_num_args() + ), + ); + zero_based_note = true; + }; + + for fmt in &self.arg_with_formatting { + if let Some(span) = fmt.precision_span { + let span = self.fmtsp.from_inner(InnerSpan::new(span.start, span.end)); + match fmt.precision { + parse::CountIsParam(pos) if pos > self.num_args() => { + e.span_label( + span, + &format!( + "this precision flag expects an `usize` argument at position {}, \ + but {}", + pos, + self.describe_num_args(), + ), + ); + zero_based_note = true; + } + parse::CountIsParam(pos) => { + let count = self.pieces.len() + + self + .arg_with_formatting + .iter() + .filter(|fmt| fmt.precision_span.is_some()) + .count(); + e.span_label( + span, + &format!( + "this precision flag adds an extra required argument at position {}, \ + which is why there {} expected", + pos, + if count == 1 { + "is 1 argument".to_string() + } else { + format!("are {} arguments", count) + }, + ), + ); + if let Some(arg) = self.args.get(pos) { + e.span_label( + arg.span, + "this parameter corresponds to the precision flag", + ); + } + zero_based_note = true; + } + _ => {} + } + } + if let Some(span) = fmt.width_span { + let span = self.fmtsp.from_inner(InnerSpan::new(span.start, span.end)); + match fmt.width { + parse::CountIsParam(pos) if pos >= self.num_args() => { + e.span_label( + span, + &format!( + "this width flag expects an `usize` argument at position {}, \ + but {}", + pos, + self.describe_num_args(), + ), + ); + zero_based_note = true; + } + _ => {} + } + } + } + if zero_based_note { + e.note("positional arguments are zero-based"); + } + if !self.arg_with_formatting.is_empty() { + e.note( + "for information about formatting flags, visit \ + https://doc.rust-lang.org/std/fmt/index.html", + ); + } + + e.emit(); + } + + /// Actually verifies and tracks a given format placeholder + /// (a.k.a. argument). + fn verify_arg_type(&mut self, arg: Position, ty: ArgumentType) { + if let Exact(arg) = arg { + if arg >= self.num_args() { + self.invalid_refs.push((arg, self.curpiece)); + return; + } + } + + match arg { + Exact(arg) | Capture(arg) => { + match ty { + Placeholder(_) => { + // record every (position, type) combination only once + let seen_ty = &mut self.arg_unique_types[arg]; + let i = seen_ty.iter().position(|x| *x == ty).unwrap_or_else(|| { + let i = seen_ty.len(); + seen_ty.push(ty); + i + }); + self.arg_types[arg].push(i); + } + Count => { + if let Entry::Vacant(e) = self.count_positions.entry(arg) { + let i = self.count_positions_count; + e.insert(i); + self.count_args.push(arg); + self.count_positions_count += 1; + } + } + } + } + + Named(name, span) => { + match self.names.get(&name) { + Some(&idx) => { + // Treat as positional arg. + self.verify_arg_type(Capture(idx.0), ty) + } + None => { + // For the moment capturing variables from format strings expanded from macros is + // disabled (see RFC #2795) + if self.is_literal { + // Treat this name as a variable to capture from the surrounding scope + let idx = self.args.len(); + self.arg_types.push(Vec::new()); + self.arg_unique_types.push(Vec::new()); + let span = if self.is_literal { + self.fmtsp.from_inner(span) + } else { + self.fmtsp + }; + self.num_captured_args += 1; + self.args.push(self.ecx.expr_ident(span, Ident::new(name, span))); + self.names.insert(name, (idx, span)); + self.verify_arg_type(Capture(idx), ty) + } else { + let msg = format!("there is no argument named `{}`", name); + let sp = if self.is_literal { + self.fmtsp.from_inner(span) + } else { + self.fmtsp + }; + let mut err = self.ecx.struct_span_err(sp, &msg); + + err.note(&format!( + "did you intend to capture a variable `{}` from \ + the surrounding scope?", + name + )); + err.note( + "to avoid ambiguity, `format_args!` cannot capture variables \ + when the format string is expanded from a macro", + ); + + err.emit(); + } + } + } + } + } + } + + /// Builds the mapping between format placeholders and argument objects. + fn build_index_map(&mut self) { + // NOTE: Keep the ordering the same as `into_expr`'s expansion would do! + let args_len = self.args.len(); + self.arg_index_map.reserve(args_len); + + let mut sofar = 0usize; + + // Map the arguments + for i in 0..args_len { + let arg_types = &self.arg_types[i]; + let arg_offsets = arg_types.iter().map(|offset| sofar + *offset).collect::<Vec<_>>(); + self.arg_index_map.push(arg_offsets); + sofar += self.arg_unique_types[i].len(); + } + + // Record starting index for counts, which appear just after arguments + self.count_args_index_offset = sofar; + } + + fn rtpath(ecx: &ExtCtxt<'_>, s: Symbol) -> Vec<Ident> { + ecx.std_path(&[sym::fmt, sym::rt, sym::v1, s]) + } + + fn build_count(&self, c: parse::Count<'_>) -> P<ast::Expr> { + let sp = self.macsp; + let count = |c, arg| { + let mut path = Context::rtpath(self.ecx, sym::Count); + path.push(Ident::new(c, sp)); + match arg { + Some(arg) => self.ecx.expr_call_global(sp, path, vec![arg]), + None => self.ecx.expr_path(self.ecx.path_global(sp, path)), + } + }; + match c { + parse::CountIs(i) => count(sym::Is, Some(self.ecx.expr_usize(sp, i))), + parse::CountIsParam(i) => { + // This needs mapping too, as `i` is referring to a macro + // argument. If `i` is not found in `count_positions` then + // the error had already been emitted elsewhere. + let i = self.count_positions.get(&i).cloned().unwrap_or(0) + + self.count_args_index_offset; + count(sym::Param, Some(self.ecx.expr_usize(sp, i))) + } + parse::CountImplied => count(sym::Implied, None), + // should never be the case, names are already resolved + parse::CountIsName(..) => panic!("should never happen"), + } + } + + /// Build a literal expression from the accumulated string literals + fn build_literal_string(&mut self) -> P<ast::Expr> { + let sp = self.fmtsp; + let s = Symbol::intern(&self.literal); + self.literal.clear(); + self.ecx.expr_str(sp, s) + } + + /// Builds a static `rt::Argument` from a `parse::Piece` or append + /// to the `literal` string. + fn build_piece( + &mut self, + piece: &parse::Piece<'a>, + arg_index_consumed: &mut Vec<usize>, + ) -> Option<P<ast::Expr>> { + let sp = self.macsp; + match *piece { + parse::String(s) => { + self.literal.push_str(s); + None + } + parse::NextArgument(ref arg) => { + // Build the position + let pos = { + match arg.position { + parse::ArgumentIs(i, ..) | parse::ArgumentImplicitlyIs(i) => { + // Map to index in final generated argument array + // in case of multiple types specified + let arg_idx = match arg_index_consumed.get_mut(i) { + None => 0, // error already emitted elsewhere + Some(offset) => { + let idx_map = &self.arg_index_map[i]; + // unwrap_or branch: error already emitted elsewhere + let arg_idx = *idx_map.get(*offset).unwrap_or(&0); + *offset += 1; + arg_idx + } + }; + self.ecx.expr_usize(sp, arg_idx) + } + + // should never be the case, because names are already + // resolved. + parse::ArgumentNamed(..) => panic!("should never happen"), + } + }; + + let simple_arg = parse::Argument { + position: { + // We don't have ArgumentNext any more, so we have to + // track the current argument ourselves. + let i = self.curarg; + self.curarg += 1; + parse::ArgumentIs(i) + }, + position_span: arg.position_span, + format: parse::FormatSpec { + fill: arg.format.fill, + align: parse::AlignUnknown, + flags: 0, + precision: parse::CountImplied, + precision_span: None, + width: parse::CountImplied, + width_span: None, + ty: arg.format.ty, + ty_span: arg.format.ty_span, + }, + }; + + let fill = arg.format.fill.unwrap_or(' '); + + let pos_simple = arg.position.index() == simple_arg.position.index(); + + if arg.format.precision_span.is_some() || arg.format.width_span.is_some() { + self.arg_with_formatting.push(arg.format); + } + if !pos_simple || arg.format != simple_arg.format || fill != ' ' { + self.all_pieces_simple = false; + } + + // Build the format + let fill = self.ecx.expr_lit(sp, ast::LitKind::Char(fill)); + let align = |name| { + let mut p = Context::rtpath(self.ecx, sym::Alignment); + p.push(Ident::new(name, sp)); + self.ecx.path_global(sp, p) + }; + let align = match arg.format.align { + parse::AlignLeft => align(sym::Left), + parse::AlignRight => align(sym::Right), + parse::AlignCenter => align(sym::Center), + parse::AlignUnknown => align(sym::Unknown), + }; + let align = self.ecx.expr_path(align); + let flags = self.ecx.expr_u32(sp, arg.format.flags); + let prec = self.build_count(arg.format.precision); + let width = self.build_count(arg.format.width); + let path = self.ecx.path_global(sp, Context::rtpath(self.ecx, sym::FormatSpec)); + let fmt = self.ecx.expr_struct( + sp, + path, + vec![ + self.ecx.field_imm(sp, Ident::new(sym::fill, sp), fill), + self.ecx.field_imm(sp, Ident::new(sym::align, sp), align), + self.ecx.field_imm(sp, Ident::new(sym::flags, sp), flags), + self.ecx.field_imm(sp, Ident::new(sym::precision, sp), prec), + self.ecx.field_imm(sp, Ident::new(sym::width, sp), width), + ], + ); + + let path = self.ecx.path_global(sp, Context::rtpath(self.ecx, sym::Argument)); + Some(self.ecx.expr_struct( + sp, + path, + vec![ + self.ecx.field_imm(sp, Ident::new(sym::position, sp), pos), + self.ecx.field_imm(sp, Ident::new(sym::format, sp), fmt), + ], + )) + } + } + } + + /// Actually builds the expression which the format_args! block will be + /// expanded to. + fn into_expr(self) -> P<ast::Expr> { + let mut original_args = self.args; + let mut fmt_args = Vec::with_capacity( + self.arg_unique_types.iter().map(|v| v.len()).sum::<usize>() + self.count_args.len(), + ); + + // First, build up the static array which will become our precompiled + // format "string" + let pieces = self.ecx.expr_array_ref(self.fmtsp, self.str_pieces); + + // We need to construct a &[ArgumentV1] to pass into the fmt::Arguments + // constructor. In general the expressions in this slice might be + // permuted from their order in original_args (such as in the case of + // "{1} {0}"), or may have multiple entries referring to the same + // element of original_args ("{0} {0}"). + // + // The following vector has one item per element of our output slice, + // identifying the index of which element of original_args it's passing, + // and that argument's type. + let mut fmt_arg_index_and_ty = SmallVec::<[(usize, &ArgumentType); 8]>::new(); + for (i, unique_types) in self.arg_unique_types.iter().enumerate() { + fmt_arg_index_and_ty.extend(unique_types.iter().map(|ty| (i, ty))); + } + fmt_arg_index_and_ty.extend(self.count_args.iter().map(|&i| (i, &Count))); + + // Figure out whether there are permuted or repeated elements. If not, + // we can generate simpler code. + // + // The sequence has no indices out of order or repeated if: for every + // adjacent pair of elements, the first one's index is less than the + // second one's index. + let nicely_ordered = + fmt_arg_index_and_ty.array_windows().all(|[(i, _i_ty), (j, _j_ty)]| i < j); + + // We want to emit: + // + // [ArgumentV1::new(&$arg0, …), ArgumentV1::new(&$arg1, …), …] + // + // However, it's only legal to do so if $arg0, $arg1, … were written in + // exactly that order by the programmer. When arguments are permuted, we + // want them evaluated in the order written by the programmer, not in + // the order provided to fmt::Arguments. When arguments are repeated, we + // want the expression evaluated only once. + // + // Further, if any arg _after the first one_ contains a yield point such + // as `await` or `yield`, the above short form is inconvenient for the + // caller because it would keep a temporary of type ArgumentV1 alive + // across the yield point. ArgumentV1 can't implement Send since it + // holds a type-erased arbitrary type. + // + // Thus in the not nicely ordered case, and in the yielding case, we + // emit the following instead: + // + // match (&$arg0, &$arg1, …) { + // args => [ArgumentV1::new(args.$i, …), ArgumentV1::new(args.$j, …), …] + // } + // + // for the sequence of indices $i, $j, … governed by fmt_arg_index_and_ty. + // This more verbose representation ensures that all arguments are + // evaluated a single time each, in the order written by the programmer, + // and that the surrounding future/generator (if any) is Send whenever + // possible. + let no_need_for_match = + nicely_ordered && !original_args.iter().skip(1).any(|e| may_contain_yield_point(e)); + + for (arg_index, arg_ty) in fmt_arg_index_and_ty { + let e = &mut original_args[arg_index]; + let span = e.span; + let arg = if no_need_for_match { + let expansion_span = e.span.with_ctxt(self.macsp.ctxt()); + // The indices are strictly ordered so e has not been taken yet. + self.ecx.expr_addr_of(expansion_span, P(e.take())) + } else { + let def_site = self.ecx.with_def_site_ctxt(span); + let args_tuple = self.ecx.expr_ident(def_site, Ident::new(sym::args, def_site)); + let member = Ident::new(sym::integer(arg_index), def_site); + self.ecx.expr(def_site, ast::ExprKind::Field(args_tuple, member)) + }; + fmt_args.push(Context::format_arg(self.ecx, self.macsp, span, arg_ty, arg)); + } + + let args_array = self.ecx.expr_array(self.macsp, fmt_args); + let args_slice = self.ecx.expr_addr_of( + self.macsp, + if no_need_for_match { + args_array + } else { + // In the !no_need_for_match case, none of the exprs were moved + // away in the previous loop. + // + // This uses the arg span for `&arg` so that borrowck errors + // point to the specific expression passed to the macro (the + // span is otherwise unavailable in the MIR used by borrowck). + let heads = original_args + .into_iter() + .map(|e| self.ecx.expr_addr_of(e.span.with_ctxt(self.macsp.ctxt()), e)) + .collect(); + + let pat = self.ecx.pat_ident(self.macsp, Ident::new(sym::args, self.macsp)); + let arm = self.ecx.arm(self.macsp, pat, args_array); + let head = self.ecx.expr(self.macsp, ast::ExprKind::Tup(heads)); + self.ecx.expr_match(self.macsp, head, vec![arm]) + }, + ); + + // Now create the fmt::Arguments struct with all our locals we created. + let (fn_name, fn_args) = if self.all_pieces_simple { + ("new_v1", vec![pieces, args_slice]) + } else { + // Build up the static array which will store our precompiled + // nonstandard placeholders, if there are any. + let fmt = self.ecx.expr_array_ref(self.macsp, self.pieces); + + let path = self.ecx.std_path(&[sym::fmt, sym::UnsafeArg, sym::new]); + let unsafe_arg = self.ecx.expr_call_global(self.macsp, path, Vec::new()); + let unsafe_expr = self.ecx.expr_block(P(ast::Block { + stmts: vec![self.ecx.stmt_expr(unsafe_arg)], + id: ast::DUMMY_NODE_ID, + rules: BlockCheckMode::Unsafe(UnsafeSource::CompilerGenerated), + span: self.macsp, + tokens: None, + could_be_bare_literal: false, + })); + + ("new_v1_formatted", vec![pieces, args_slice, fmt, unsafe_expr]) + }; + + let path = self.ecx.std_path(&[sym::fmt, sym::Arguments, Symbol::intern(fn_name)]); + self.ecx.expr_call_global(self.macsp, path, fn_args) + } + + fn format_arg( + ecx: &ExtCtxt<'_>, + macsp: Span, + mut sp: Span, + ty: &ArgumentType, + arg: P<ast::Expr>, + ) -> P<ast::Expr> { + sp = ecx.with_def_site_ctxt(sp); + let trait_ = match *ty { + Placeholder(trait_) if trait_ == "<invalid>" => return DummyResult::raw_expr(sp, true), + Placeholder(trait_) => trait_, + Count => { + let path = ecx.std_path(&[sym::fmt, sym::ArgumentV1, sym::from_usize]); + return ecx.expr_call_global(macsp, path, vec![arg]); + } + }; + let new_fn_name = match trait_ { + "Display" => "new_display", + "Debug" => "new_debug", + "LowerExp" => "new_lower_exp", + "UpperExp" => "new_upper_exp", + "Octal" => "new_octal", + "Pointer" => "new_pointer", + "Binary" => "new_binary", + "LowerHex" => "new_lower_hex", + "UpperHex" => "new_upper_hex", + _ => unreachable!(), + }; + + let path = ecx.std_path(&[sym::fmt, sym::ArgumentV1, Symbol::intern(new_fn_name)]); + ecx.expr_call_global(sp, path, vec![arg]) + } +} + +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, names)) => { + MacEager::expr(expand_preparsed_format_args(ecx, sp, efmt, args, names, nl)) + } + 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) +} + +fn create_lints_for_named_arguments_used_positionally(cx: &mut Context<'_, '_>) { + for named_arg in &cx.unused_names_lint.positional_named_args { + let (position_sp_to_replace, position_sp_for_msg) = named_arg.get_positional_arg_spans(cx); + + let msg = format!("named argument `{}` is not used by name", named_arg.replacement); + + cx.ecx.buffered_early_lint.push(BufferedEarlyLint { + span: MultiSpan::from_span(named_arg.positional_named_arg_span), + msg: msg.clone(), + node_id: 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: named_arg.positional_named_arg_span, + named_arg_name: named_arg.replacement.to_string(), + is_formatting_arg: named_arg.ty != PositionalNamedArgType::Arg, + }, + }); + } +} + +/// Take the various parts of `format_args!(efmt, args..., name=names...)` +/// and construct the appropriate formatting expression. +pub fn expand_preparsed_format_args( + ecx: &mut ExtCtxt<'_>, + sp: Span, + efmt: P<ast::Expr>, + args: Vec<FormatArg>, + names: FxHashMap<Symbol, (usize, Span)>, + append_newline: bool, +) -> P<ast::Expr> { + // NOTE: this verbose way of initializing `Vec<Vec<ArgumentType>>` is because + // `ArgumentType` does not derive `Clone`. + let arg_types: Vec<_> = (0..args.len()).map(|_| Vec::new()).collect(); + let arg_unique_types: Vec<_> = (0..args.len()).map(|_| Vec::new()).collect(); + + let mut macsp = ecx.call_site(); + macsp = ecx.with_def_site_ctxt(macsp); + + let msg = "format argument must be a string literal"; + let fmt_sp = efmt.span; + let efmt_kind_is_lit: bool = matches!(efmt.kind, ast::ExprKind::Lit(_)); + 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.len() { + 0 => "{}".to_string(), + _ => format!("{}{{}}", "{} ".repeat(args.len())), + }; + if !suggested { + err.span_suggestion( + fmt_sp.shrink_to_lo(), + "you might be missing a string literal to format with", + format!("\"{}\", ", sugg_fmt), + Applicability::MaybeIncorrect, + ); + } + err.emit(); + } + return DummyResult::raw_expr(sp, true); + } + }; + + let str_style = match fmt_style { + ast::StrStyle::Cooked => None, + 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(fmt_sp).ok(); + let mut parser = parse::Parser::new( + fmt_str, + str_style, + fmt_snippet, + append_newline, + parse::ParseMode::Format, + ); + + let mut unverified_pieces = Vec::new(); + while let Some(piece) = parser.next() { + if !parser.errors.is_empty() { + break; + } else { + unverified_pieces.push(piece); + } + } + + if !parser.errors.is_empty() { + let err = parser.errors.remove(0); + let sp = if efmt_kind_is_lit { + 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 { + if efmt_kind_is_lit { + 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)); + let positional_args = args.iter().filter(|arg| !arg.named).collect::<Vec<_>>(); + if let Ok(arg) = ecx.source_map().span_to_snippet(captured_arg_span) { + let span = match positional_args.last() { + Some(arg) => arg.expr.span, + None => fmt_sp, + }; + e.multipart_suggestion_verbose( + "consider using a positional formatting argument instead", + vec![ + (captured_arg_span, positional_args.len().to_string()), + (span.shrink_to_hi(), format!(", {}", arg)), + ], + Applicability::MachineApplicable, + ); + } + } + e.emit(); + return DummyResult::raw_expr(sp, true); + } + + let arg_spans = parser + .arg_places + .iter() + .map(|span| fmt_span.from_inner(InnerSpan::new(span.start, span.end))) + .collect(); + + let named_pos: FxHashSet<usize> = names.values().cloned().map(|(i, _)| i).collect(); + + let mut cx = Context { + ecx, + args: args.into_iter().map(|arg| arg.expr).collect(), + num_captured_args: 0, + arg_types, + arg_unique_types, + names, + curarg: 0, + curpiece: 0, + arg_index_map: Vec::new(), + count_args: Vec::new(), + count_positions: FxHashMap::default(), + count_positions_count: 0, + count_args_index_offset: 0, + literal: String::new(), + pieces: Vec::with_capacity(unverified_pieces.len()), + str_pieces: Vec::with_capacity(unverified_pieces.len()), + all_pieces_simple: true, + macsp, + fmtsp: fmt_span, + invalid_refs: Vec::new(), + arg_spans, + arg_with_formatting: Vec::new(), + is_literal: parser.is_literal, + unused_names_lint: PositionalNamedArgsLint { positional_named_args: vec![] }, + }; + + // This needs to happen *after* the Parser has consumed all pieces to create all the spans + let pieces = unverified_pieces + .into_iter() + .map(|mut piece| { + cx.verify_piece(&piece); + cx.resolve_name_inplace(&mut piece); + piece + }) + .collect::<Vec<_>>(); + + let numbered_position_args = pieces.iter().any(|arg: &parse::Piece<'_>| match *arg { + parse::String(_) => false, + parse::NextArgument(arg) => matches!(arg.position, parse::Position::ArgumentIs(..)), + }); + + cx.build_index_map(); + + let mut arg_index_consumed = vec![0usize; cx.arg_index_map.len()]; + + for piece in pieces { + if let Some(piece) = cx.build_piece(&piece, &mut arg_index_consumed) { + let s = cx.build_literal_string(); + cx.str_pieces.push(s); + cx.pieces.push(piece); + } + } + + if !cx.literal.is_empty() { + let s = cx.build_literal_string(); + cx.str_pieces.push(s); + } + + if !cx.invalid_refs.is_empty() { + cx.report_invalid_references(numbered_position_args); + } + + // Make sure that all arguments were used and all arguments have types. + let errs = cx + .arg_types + .iter() + .enumerate() + .filter(|(i, ty)| ty.is_empty() && !cx.count_positions.contains_key(&i)) + .map(|(i, _)| { + let msg = if named_pos.contains(&i) { + // named argument + "named argument never used" + } else { + // positional argument + "argument never used" + }; + (cx.args[i].span, msg) + }) + .collect::<Vec<_>>(); + + let errs_len = errs.len(); + if !errs.is_empty() { + let args_used = cx.arg_types.len() - errs_len; + let args_unused = errs_len; + + let mut diag = { + if let [(sp, msg)] = &errs[..] { + let mut diag = cx.ecx.struct_span_err(*sp, *msg); + diag.span_label(*sp, *msg); + diag + } else { + let mut diag = cx.ecx.struct_span_err( + errs.iter().map(|&(sp, _)| sp).collect::<Vec<Span>>(), + "multiple unused formatting arguments", + ); + diag.span_label(cx.fmtsp, "multiple missing formatting specifiers"); + for (sp, msg) in errs { + diag.span_label(sp, 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 args_used < args_unused { + 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::$kind::iter_subs(fmt_str, padding) { + let (trn, success) = match sub.translate() { + Ok(trn) => (trn, true), + Err(Some(msg)) => (msg, false), + + // If it has no translation, don't call it out specifically. + _ => continue, + }; + + let pos = sub.position(); + let sub = String::from(sub.as_str()); + if explained.contains(&sub) { + continue; + } + explained.insert(sub.clone()); + + if !found_foreign { + found_foreign = true; + show_doc_note = true; + } + + if let Some(inner_sp) = pos { + let sp = fmt_sp.from_inner(inner_sp); + + if success { + suggestions.push((sp, trn)); + } else { + diag.span_note( + sp, + &format!("format specifiers use curly braces, and {}", trn), + ); + } + } else { + if success { + diag.help(&format!("`{}` should be written as `{}`", sub, trn)); + } else { + diag.note(&format!( + "`{}` should use curly braces, and {}", + sub, trn + )); + } + } + } + + if show_doc_note { + diag.note(concat!( + stringify!($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 && errs_len == 1 { + diag.span_label(cx.fmtsp, "formatting specifier missing"); + } + + diag.emit(); + } else if cx.invalid_refs.is_empty() && cx.ecx.sess.err_count() == 0 { + // 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. + create_lints_for_named_arguments_used_positionally(&mut cx); + } + + cx.into_expr() +} + +fn may_contain_yield_point(e: &ast::Expr) -> bool { + struct MayContainYieldPoint(bool); + + impl Visitor<'_> for MayContainYieldPoint { + fn visit_expr(&mut self, e: &ast::Expr) { + if let ast::ExprKind::Await(_) | ast::ExprKind::Yield(_) = e.kind { + self.0 = true; + } else { + visit::walk_expr(self, e); + } + } + + fn visit_mac_call(&mut self, _: &ast::MacCall) { + self.0 = true; + } + + fn visit_attribute(&mut self, _: &ast::Attribute) { + // Conservatively assume this may be a proc macro attribute in + // expression position. + self.0 = true; + } + + fn visit_item(&mut self, _: &ast::Item) { + // Do not recurse into nested items. + } + } + + let mut visitor = MayContainYieldPoint(false); + visitor.visit_expr(e); + visitor.0 +} |