1200 lines
47 KiB
Rust
1200 lines
47 KiB
Rust
use ArgumentType::*;
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use Position::*;
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use rustc_ast as ast;
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use rustc_ast::ptr::P;
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use rustc_ast::token;
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use rustc_ast::tokenstream::TokenStream;
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use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_errors::{pluralize, Applicability, DiagnosticBuilder};
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use rustc_expand::base::{self, *};
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use rustc_parse_format as parse;
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use rustc_span::symbol::{sym, Ident, Symbol};
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use rustc_span::{MultiSpan, Span};
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use std::borrow::Cow;
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use std::collections::hash_map::Entry;
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#[derive(PartialEq)]
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enum ArgumentType {
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Placeholder(&'static str),
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Count,
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}
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enum Position {
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Exact(usize),
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Named(Symbol),
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}
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struct Context<'a, 'b> {
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ecx: &'a mut ExtCtxt<'b>,
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/// The macro's call site. References to unstable formatting internals must
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/// use this span to pass the stability checker.
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macsp: Span,
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/// The span of the format string literal.
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fmtsp: Span,
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/// List of parsed argument expressions.
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/// Named expressions are resolved early, and are appended to the end of
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/// argument expressions.
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///
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/// Example showing the various data structures in motion:
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///
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/// * Original: `"{foo:o} {:o} {foo:x} {0:x} {1:o} {:x} {1:x} {0:o}"`
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/// * Implicit argument resolution: `"{foo:o} {0:o} {foo:x} {0:x} {1:o} {1:x} {1:x} {0:o}"`
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/// * Name resolution: `"{2:o} {0:o} {2:x} {0:x} {1:o} {1:x} {1:x} {0:o}"`
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/// * `arg_types` (in JSON): `[[0, 1, 0], [0, 1, 1], [0, 1]]`
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/// * `arg_unique_types` (in simplified JSON): `[["o", "x"], ["o", "x"], ["o", "x"]]`
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/// * `names` (in JSON): `{"foo": 2}`
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args: Vec<P<ast::Expr>>,
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/// Placeholder slot numbers indexed by argument.
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arg_types: Vec<Vec<usize>>,
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/// Unique format specs seen for each argument.
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arg_unique_types: Vec<Vec<ArgumentType>>,
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/// Map from named arguments to their resolved indices.
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names: FxHashMap<Symbol, usize>,
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/// The latest consecutive literal strings, or empty if there weren't any.
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literal: String,
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/// Collection of the compiled `rt::Argument` structures
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pieces: Vec<P<ast::Expr>>,
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/// Collection of string literals
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str_pieces: Vec<P<ast::Expr>>,
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/// Stays `true` if all formatting parameters are default (as in "{}{}").
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all_pieces_simple: bool,
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/// Mapping between positional argument references and indices into the
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/// final generated static argument array. We record the starting indices
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/// corresponding to each positional argument, and number of references
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/// consumed so far for each argument, to facilitate correct `Position`
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/// mapping in `build_piece`. In effect this can be seen as a "flattened"
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/// version of `arg_unique_types`.
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///
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/// Again with the example described above in docstring for `args`:
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///
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/// * `arg_index_map` (in JSON): `[[0, 1, 0], [2, 3, 3], [4, 5]]`
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arg_index_map: Vec<Vec<usize>>,
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/// Starting offset of count argument slots.
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count_args_index_offset: usize,
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/// Count argument slots and tracking data structures.
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/// Count arguments are separately tracked for de-duplication in case
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/// multiple references are made to one argument. For example, in this
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/// format string:
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///
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/// * Original: `"{:.*} {:.foo$} {1:.*} {:.0$}"`
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/// * Implicit argument resolution: `"{1:.0$} {2:.foo$} {1:.3$} {4:.0$}"`
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/// * Name resolution: `"{1:.0$} {2:.5$} {1:.3$} {4:.0$}"`
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/// * `count_positions` (in JSON): `{0: 0, 5: 1, 3: 2}`
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/// * `count_args`: `vec![Exact(0), Exact(5), Exact(3)]`
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count_args: Vec<Position>,
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/// Relative slot numbers for count arguments.
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count_positions: FxHashMap<usize, usize>,
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/// Number of count slots assigned.
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count_positions_count: usize,
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/// Current position of the implicit positional arg pointer, as if it
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/// still existed in this phase of processing.
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/// Used only for `all_pieces_simple` tracking in `build_piece`.
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curarg: usize,
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/// Current piece being evaluated, used for error reporting.
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curpiece: usize,
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/// Keep track of invalid references to positional arguments.
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invalid_refs: Vec<(usize, usize)>,
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/// Spans of all the formatting arguments, in order.
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arg_spans: Vec<Span>,
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/// All the formatting arguments that have formatting flags set, in order for diagnostics.
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arg_with_formatting: Vec<parse::FormatSpec<'a>>,
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/// Whether this format string came from a string literal, as opposed to a macro.
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is_literal: bool,
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}
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/// Parses the arguments from the given list of tokens, returning the diagnostic
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/// if there's a parse error so we can continue parsing other format!
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/// expressions.
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///
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/// If parsing succeeds, the return value is:
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///
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/// ```text
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/// Some((fmtstr, parsed arguments, index map for named arguments))
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/// ```
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fn parse_args<'a>(
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ecx: &mut ExtCtxt<'a>,
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sp: Span,
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tts: TokenStream,
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) -> Result<(P<ast::Expr>, Vec<P<ast::Expr>>, FxHashMap<Symbol, usize>), DiagnosticBuilder<'a>> {
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let mut args = Vec::<P<ast::Expr>>::new();
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let mut names = FxHashMap::<Symbol, usize>::default();
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let mut p = ecx.new_parser_from_tts(tts);
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if p.token == token::Eof {
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return Err(ecx.struct_span_err(sp, "requires at least a format string argument"));
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}
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let first_token = &p.token;
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let fmtstr = match first_token.kind {
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token::TokenKind::Literal(token::Lit {
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kind: token::LitKind::Str | token::LitKind::StrRaw(_),
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..
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}) => {
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// If the first token is a string literal, then a format expression
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// is constructed from it.
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//
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// This allows us to properly handle cases when the first comma
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// after the format string is mistakenly replaced with any operator,
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// which cause the expression parser to eat too much tokens.
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p.parse_literal_maybe_minus()?
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}
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_ => {
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// Otherwise, we fall back to the expression parser.
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p.parse_expr()?
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}
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};
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let mut first = true;
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let mut named = false;
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while p.token != token::Eof {
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if !p.eat(&token::Comma) {
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if first {
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p.clear_expected_tokens();
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}
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// `Parser::expect` tries to recover using the
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// `Parser::unexpected_try_recover` function. This function is able
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// to recover if the expected token is a closing delimiter.
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//
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// As `,` is not a closing delimiter, it will always return an `Err`
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// variant.
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let mut err = p.expect(&token::Comma).unwrap_err();
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match token::TokenKind::Comma.similar_tokens() {
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Some(tks) if tks.contains(&p.token.kind) => {
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// If a similar token is found, then it may be a typo. We
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// consider it as a comma, and continue parsing.
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err.emit();
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p.bump();
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}
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// Otherwise stop the parsing and return the error.
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_ => return Err(err),
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}
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}
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first = false;
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if p.token == token::Eof {
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break;
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} // accept trailing commas
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match p.token.ident() {
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Some((ident, _)) if p.look_ahead(1, |t| *t == token::Eq) => {
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named = true;
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p.bump();
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p.expect(&token::Eq)?;
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let e = p.parse_expr()?;
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if let Some(prev) = names.get(&ident.name) {
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ecx.struct_span_err(e.span, &format!("duplicate argument named `{}`", ident))
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.span_label(args[*prev].span, "previously here")
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.span_label(e.span, "duplicate argument")
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.emit();
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continue;
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}
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// Resolve names into slots early.
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// Since all the positional args are already seen at this point
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// if the input is valid, we can simply append to the positional
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// args. And remember the names.
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let slot = args.len();
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names.insert(ident.name, slot);
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args.push(e);
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}
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_ => {
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let e = p.parse_expr()?;
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if named {
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let mut err = ecx.struct_span_err(
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e.span,
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"positional arguments cannot follow named arguments",
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);
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err.span_label(e.span, "positional arguments must be before named arguments");
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for pos in names.values() {
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err.span_label(args[*pos].span, "named argument");
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}
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err.emit();
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}
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args.push(e);
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}
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}
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}
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Ok((fmtstr, args, names))
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}
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impl<'a, 'b> Context<'a, 'b> {
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fn resolve_name_inplace(&self, p: &mut parse::Piece<'_>) {
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// NOTE: the `unwrap_or` branch is needed in case of invalid format
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// arguments, e.g., `format_args!("{foo}")`.
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let lookup = |s: Symbol| *self.names.get(&s).unwrap_or(&0);
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match *p {
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parse::String(_) => {}
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parse::NextArgument(ref mut arg) => {
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if let parse::ArgumentNamed(s) = arg.position {
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arg.position = parse::ArgumentIs(lookup(s));
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}
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if let parse::CountIsName(s) = arg.format.width {
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arg.format.width = parse::CountIsParam(lookup(s));
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}
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if let parse::CountIsName(s) = arg.format.precision {
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arg.format.precision = parse::CountIsParam(lookup(s));
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}
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}
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}
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}
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/// Verifies one piece of a parse string, and remembers it if valid.
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/// All errors are not emitted as fatal so we can continue giving errors
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/// about this and possibly other format strings.
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fn verify_piece(&mut self, p: &parse::Piece<'_>) {
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match *p {
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parse::String(..) => {}
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parse::NextArgument(ref arg) => {
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// width/precision first, if they have implicit positional
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// parameters it makes more sense to consume them first.
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self.verify_count(arg.format.width);
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self.verify_count(arg.format.precision);
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// argument second, if it's an implicit positional parameter
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// it's written second, so it should come after width/precision.
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let pos = match arg.position {
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parse::ArgumentIs(i) | parse::ArgumentImplicitlyIs(i) => Exact(i),
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parse::ArgumentNamed(s) => Named(s),
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};
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let ty = Placeholder(match arg.format.ty {
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"" => "Display",
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"?" => "Debug",
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"e" => "LowerExp",
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"E" => "UpperExp",
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"o" => "Octal",
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"p" => "Pointer",
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"b" => "Binary",
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"x" => "LowerHex",
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"X" => "UpperHex",
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_ => {
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let fmtsp = self.fmtsp;
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let sp = arg.format.ty_span.map(|sp| fmtsp.from_inner(sp));
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let mut err = self.ecx.struct_span_err(
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sp.unwrap_or(fmtsp),
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&format!("unknown format trait `{}`", arg.format.ty),
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);
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err.note(
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"the only appropriate formatting traits are:\n\
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- ``, which uses the `Display` trait\n\
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- `?`, which uses the `Debug` trait\n\
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- `e`, which uses the `LowerExp` trait\n\
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- `E`, which uses the `UpperExp` trait\n\
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- `o`, which uses the `Octal` trait\n\
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- `p`, which uses the `Pointer` trait\n\
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- `b`, which uses the `Binary` trait\n\
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- `x`, which uses the `LowerHex` trait\n\
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- `X`, which uses the `UpperHex` trait",
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);
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if let Some(sp) = sp {
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for (fmt, name) in &[
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("", "Display"),
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("?", "Debug"),
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("e", "LowerExp"),
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("E", "UpperExp"),
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("o", "Octal"),
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("p", "Pointer"),
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("b", "Binary"),
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("x", "LowerHex"),
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("X", "UpperHex"),
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] {
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// FIXME: rustfix (`run-rustfix`) fails to apply suggestions.
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// > "Cannot replace slice of data that was already replaced"
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err.tool_only_span_suggestion(
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sp,
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&format!("use the `{}` trait", name),
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(*fmt).to_string(),
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Applicability::MaybeIncorrect,
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);
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}
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}
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err.emit();
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"<invalid>"
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}
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});
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self.verify_arg_type(pos, ty);
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self.curpiece += 1;
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}
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}
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}
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fn verify_count(&mut self, c: parse::Count) {
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match c {
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parse::CountImplied | parse::CountIs(..) => {}
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parse::CountIsParam(i) => {
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self.verify_arg_type(Exact(i), Count);
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}
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parse::CountIsName(s) => {
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self.verify_arg_type(Named(s), Count);
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}
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}
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}
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fn describe_num_args(&self) -> Cow<'_, str> {
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match self.args.len() {
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0 => "no arguments were given".into(),
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1 => "there is 1 argument".into(),
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x => format!("there are {} arguments", x).into(),
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}
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}
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/// Handle invalid references to positional arguments. Output different
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/// errors for the case where all arguments are positional and for when
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/// there are named arguments or numbered positional arguments in the
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/// format string.
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fn report_invalid_references(&self, numbered_position_args: bool) {
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let mut e;
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let sp = if !self.arg_spans.is_empty() {
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// Point at the formatting arguments.
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MultiSpan::from_spans(self.arg_spans.clone())
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} else {
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MultiSpan::from_span(self.fmtsp)
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};
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let refs =
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self.invalid_refs.iter().map(|(r, pos)| (r.to_string(), self.arg_spans.get(*pos)));
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let mut zero_based_note = false;
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let count = self.pieces.len()
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+ self.arg_with_formatting.iter().filter(|fmt| fmt.precision_span.is_some()).count();
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if self.names.is_empty() && !numbered_position_args && count != self.args.len() {
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e = self.ecx.struct_span_err(
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sp,
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&format!(
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"{} positional argument{} in format string, but {}",
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count,
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pluralize!(count),
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self.describe_num_args(),
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),
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);
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for arg in &self.args {
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// Point at the arguments that will be formatted.
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e.span_label(arg.span, "");
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}
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} else {
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let (mut refs, spans): (Vec<_>, Vec<_>) = refs.unzip();
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// Avoid `invalid reference to positional arguments 7 and 7 (there is 1 argument)`
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// for `println!("{7:7$}", 1);`
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refs.sort();
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refs.dedup();
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let spans: Vec<_> = spans.into_iter().filter_map(|sp| sp.copied()).collect();
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let sp = if self.arg_spans.is_empty() || spans.is_empty() {
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MultiSpan::from_span(self.fmtsp)
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} else {
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MultiSpan::from_spans(spans)
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};
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let arg_list = if refs.len() == 1 {
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format!("argument {}", refs[0])
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} else {
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let reg = refs.pop().unwrap();
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format!("arguments {head} and {tail}", head = refs.join(", "), tail = reg)
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};
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e = self.ecx.struct_span_err(
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sp,
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&format!(
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"invalid reference to positional {} ({})",
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arg_list,
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self.describe_num_args()
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),
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);
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zero_based_note = true;
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};
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for fmt in &self.arg_with_formatting {
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if let Some(span) = fmt.precision_span {
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let span = self.fmtsp.from_inner(span);
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match fmt.precision {
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parse::CountIsParam(pos) if pos > self.args.len() => {
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e.span_label(
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span,
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&format!(
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"this precision flag expects an `usize` argument at position {}, \
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but {}",
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pos,
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self.describe_num_args(),
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),
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);
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zero_based_note = true;
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}
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parse::CountIsParam(pos) => {
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let count = self.pieces.len()
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+ self
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.arg_with_formatting
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.iter()
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.filter(|fmt| fmt.precision_span.is_some())
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.count();
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e.span_label(span, &format!(
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"this precision flag adds an extra required argument at position {}, \
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which is why there {} expected",
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pos,
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if count == 1 {
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"is 1 argument".to_string()
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} else {
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format!("are {} arguments", count)
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},
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));
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if let Some(arg) = self.args.get(pos) {
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e.span_label(
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arg.span,
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"this parameter corresponds to the precision flag",
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);
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}
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zero_based_note = true;
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}
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_ => {}
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}
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}
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if let Some(span) = fmt.width_span {
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let span = self.fmtsp.from_inner(span);
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match fmt.width {
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parse::CountIsParam(pos) if pos > self.args.len() => {
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e.span_label(
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span,
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&format!(
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"this width flag expects an `usize` argument at position {}, \
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but {}",
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pos,
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self.describe_num_args(),
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),
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);
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zero_based_note = true;
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}
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_ => {}
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}
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}
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}
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if zero_based_note {
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e.note("positional arguments are zero-based");
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}
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if !self.arg_with_formatting.is_empty() {
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e.note(
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"for information about formatting flags, visit \
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https://doc.rust-lang.org/std/fmt/index.html",
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);
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}
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e.emit();
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}
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|
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/// Actually verifies and tracks a given format placeholder
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/// (a.k.a. argument).
|
|
fn verify_arg_type(&mut self, arg: Position, ty: ArgumentType) {
|
|
match arg {
|
|
Exact(arg) => {
|
|
if self.args.len() <= arg {
|
|
self.invalid_refs.push((arg, self.curpiece));
|
|
return;
|
|
}
|
|
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(Exact(arg));
|
|
self.count_positions_count += 1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
Named(name) => {
|
|
match self.names.get(&name) {
|
|
Some(&idx) => {
|
|
// Treat as positional arg.
|
|
self.verify_arg_type(Exact(idx), ty)
|
|
}
|
|
None => {
|
|
let capture_feature_enabled = self
|
|
.ecx
|
|
.ecfg
|
|
.features
|
|
.map_or(false, |features| features.format_args_capture);
|
|
|
|
// For the moment capturing variables from format strings expanded from macros is
|
|
// disabled (see RFC #2795)
|
|
let can_capture = capture_feature_enabled && self.is_literal;
|
|
|
|
if can_capture {
|
|
// 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.arg_spans.get(self.curpiece).unwrap_or(&self.fmtsp)
|
|
} else {
|
|
self.fmtsp
|
|
};
|
|
self.args.push(self.ecx.expr_ident(span, Ident::new(name, span)));
|
|
self.names.insert(name, idx);
|
|
self.verify_arg_type(Exact(idx), ty)
|
|
} else {
|
|
let msg = format!("there is no argument named `{}`", name);
|
|
let sp = if self.is_literal {
|
|
*self.arg_spans.get(self.curpiece).unwrap_or(&self.fmtsp)
|
|
} else {
|
|
self.fmtsp
|
|
};
|
|
let mut err = self.ecx.struct_span_err(sp, &msg[..]);
|
|
|
|
if capture_feature_enabled && !self.is_literal {
|
|
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",
|
|
);
|
|
} else if self.ecx.parse_sess().unstable_features.is_nightly_build() {
|
|
err.help(&format!(
|
|
"if you intended to capture `{}` from the surrounding scope, add \
|
|
`#![feature(format_args_capture)]` to the crate attributes",
|
|
name
|
|
));
|
|
}
|
|
|
|
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)
|
|
},
|
|
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 locals =
|
|
Vec::with_capacity((0..self.args.len()).map(|i| self.arg_unique_types[i].len()).sum());
|
|
let mut counts = Vec::with_capacity(self.count_args.len());
|
|
let mut pats = Vec::with_capacity(self.args.len());
|
|
let mut heads = Vec::with_capacity(self.args.len());
|
|
|
|
let names_pos: Vec<_> = (0..self.args.len())
|
|
.map(|i| Ident::from_str_and_span(&format!("arg{}", i), self.macsp))
|
|
.collect();
|
|
|
|
// First, build up the static array which will become our precompiled
|
|
// format "string"
|
|
let pieces = self.ecx.expr_vec_slice(self.fmtsp, self.str_pieces);
|
|
|
|
// Before consuming the expressions, we have to remember spans for
|
|
// count arguments as they are now generated separate from other
|
|
// arguments, hence have no access to the `P<ast::Expr>`'s.
|
|
let spans_pos: Vec<_> = self.args.iter().map(|e| e.span).collect();
|
|
|
|
// Right now there is a bug such that for the expression:
|
|
// foo(bar(&1))
|
|
// the lifetime of `1` doesn't outlast the call to `bar`, so it's not
|
|
// valid for the call to `foo`. To work around this all arguments to the
|
|
// format! string are shoved into locals. Furthermore, we shove the address
|
|
// of each variable because we don't want to move out of the arguments
|
|
// passed to this function.
|
|
for (i, e) in self.args.into_iter().enumerate() {
|
|
let name = names_pos[i];
|
|
let span = self.ecx.with_def_site_ctxt(e.span);
|
|
pats.push(self.ecx.pat_ident(span, name));
|
|
for arg_ty in self.arg_unique_types[i].iter() {
|
|
locals.push(Context::format_arg(self.ecx, self.macsp, e.span, arg_ty, name));
|
|
}
|
|
heads.push(self.ecx.expr_addr_of(e.span, e));
|
|
}
|
|
for pos in self.count_args {
|
|
let index = match pos {
|
|
Exact(i) => i,
|
|
_ => panic!("should never happen"),
|
|
};
|
|
let name = names_pos[index];
|
|
let span = spans_pos[index];
|
|
counts.push(Context::format_arg(self.ecx, self.macsp, span, &Count, name));
|
|
}
|
|
|
|
// Now create a vector containing all the arguments
|
|
let args = locals.into_iter().chain(counts.into_iter());
|
|
|
|
let args_array = self.ecx.expr_vec(self.macsp, args.collect());
|
|
|
|
// Constructs an AST equivalent to:
|
|
//
|
|
// match (&arg0, &arg1) {
|
|
// (tmp0, tmp1) => args_array
|
|
// }
|
|
//
|
|
// It was:
|
|
//
|
|
// let tmp0 = &arg0;
|
|
// let tmp1 = &arg1;
|
|
// args_array
|
|
//
|
|
// Because of #11585 the new temporary lifetime rule, the enclosing
|
|
// statements for these temporaries become the let's themselves.
|
|
// If one or more of them are RefCell's, RefCell borrow() will also
|
|
// end there; they don't last long enough for args_array to use them.
|
|
// The match expression solves the scope problem.
|
|
//
|
|
// Note, it may also very well be transformed to:
|
|
//
|
|
// match arg0 {
|
|
// ref tmp0 => {
|
|
// match arg1 => {
|
|
// ref tmp1 => args_array } } }
|
|
//
|
|
// But the nested match expression is proved to perform not as well
|
|
// as series of let's; the first approach does.
|
|
let pat = self.ecx.pat_tuple(self.macsp, pats);
|
|
let arm = self.ecx.arm(self.macsp, pat, args_array);
|
|
let head = self.ecx.expr(self.macsp, ast::ExprKind::Tup(heads));
|
|
let result = self.ecx.expr_match(self.macsp, head, vec![arm]);
|
|
|
|
let args_slice = self.ecx.expr_addr_of(self.macsp, result);
|
|
|
|
// 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_vec_slice(self.macsp, self.pieces);
|
|
|
|
("new_v1_formatted", vec![pieces, args_slice, fmt])
|
|
};
|
|
|
|
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: Ident,
|
|
) -> P<ast::Expr> {
|
|
sp = ecx.with_def_site_ctxt(sp);
|
|
let arg = ecx.expr_ident(sp, arg);
|
|
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 path = ecx.std_path(&[sym::fmt, Symbol::intern(trait_), sym::fmt]);
|
|
let format_fn = ecx.path_global(sp, path);
|
|
let path = ecx.std_path(&[sym::fmt, sym::ArgumentV1, sym::new]);
|
|
ecx.expr_call_global(macsp, path, vec![arg, ecx.expr_path(format_fn)])
|
|
}
|
|
}
|
|
|
|
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)
|
|
}
|
|
|
|
/// 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<P<ast::Expr>>,
|
|
names: FxHashMap<Symbol, usize>,
|
|
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) = err {
|
|
let sugg_fmt = match args.len() {
|
|
0 => "{}".to_string(),
|
|
_ => format!("{}{{}}", "{} ".repeat(args.len())),
|
|
};
|
|
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(err.span)
|
|
} 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 {
|
|
let sp = fmt_span.from_inner(span);
|
|
e.span_label(sp, label);
|
|
}
|
|
e.emit();
|
|
return DummyResult::raw_expr(sp, true);
|
|
}
|
|
|
|
let arg_spans = parser.arg_places.iter().map(|span| fmt_span.from_inner(*span)).collect();
|
|
|
|
let named_pos: FxHashSet<usize> = names.values().cloned().collect();
|
|
|
|
let mut cx = Context {
|
|
ecx,
|
|
args,
|
|
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,
|
|
};
|
|
|
|
// 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::$kind::iter_subs(fmt_str, padding) {
|
|
let trn = match sub.translate() {
|
|
Some(trn) => trn,
|
|
|
|
// If it has no translation, don't call it out specifically.
|
|
None => continue,
|
|
};
|
|
|
|
let pos = sub.position();
|
|
let sub = String::from(sub.as_str());
|
|
if explained.contains(&sub) {
|
|
continue;
|
|
}
|
|
explained.insert(sub.clone());
|
|
|
|
if !found_foreign {
|
|
found_foreign = true;
|
|
show_doc_note = true;
|
|
}
|
|
|
|
if let Some(inner_sp) = pos {
|
|
let sp = fmt_sp.from_inner(inner_sp);
|
|
suggestions.push((sp, trn));
|
|
} else {
|
|
diag.help(&format!("`{}` should be written as `{}`", sub, trn));
|
|
}
|
|
}
|
|
|
|
if show_doc_note {
|
|
diag.note(concat!(
|
|
stringify!($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();
|
|
}
|
|
|
|
cx.into_expr()
|
|
}
|