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-rw-r--r--compiler/rustc_builtin_macros/src/format.rs1573
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(&note);
+ }
+ 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
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-12 03:27:57 +0000