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Rollup merge of #100058 - TaKO8Ki:suggest-positional-formatting-argument-instead-of-format-args-capture, r=estebank

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Suggest a positional formatting argument instead of a captured argument

This patch fixes a part of #96999.

fixes #98241
fixes #97311

r? `@estebank`
This commit is contained in:
Matthias Krüger 2022-08-04 22:25:01 +02:00 • committed by GitHub
commit d3aa757ff8
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 182 additions and 8 deletions
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40
compiler/rustc_builtin_macros/src/format.rs
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@ -280,6 +280,11 @@ struct Context<'a, 'b> {
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.
@ -293,8 +298,8 @@ fn parse_args<'a>(
ecx: &mut ExtCtxt<'a>,
sp: Span,
tts: TokenStream,
) -> PResult<'a, (P<ast::Expr>, Vec<P<ast::Expr>>, FxHashMap<Symbol, (usize, Span)>)> {
let mut args = Vec::<P<ast::Expr>>::new();
) -> 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);
@ -362,7 +367,7 @@ fn parse_args<'a>(
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].span, "previously here")
.span_label(args[*prev].expr.span, "previously here")
.span_label(e.span, "duplicate argument")
.emit();
continue;
@ -374,7 +379,7 @@ fn parse_args<'a>(
// args. And remember the names.
let slot = args.len();
names.insert(ident.name, (slot, ident.span));
args.push(e);
args.push(FormatArg { expr: e, named: true });
}
_ => {
let e = p.parse_expr()?;
@ -385,11 +390,11 @@ fn parse_args<'a>(
);
err.span_label(e.span, "positional arguments must be before named arguments");
for pos in names.values() {
err.span_label(args[pos.0].span, "named argument");
err.span_label(args[pos.0].expr.span, "named argument");
}
err.emit();
}
args.push(e);
args.push(FormatArg { expr: e, named: false });
}
}
}
@ -1214,7 +1219,7 @@ pub fn expand_preparsed_format_args(
ecx: &mut ExtCtxt<'_>,
sp: Span,
efmt: P<ast::Expr>,
args: Vec<P<ast::Expr>>,
args: Vec<FormatArg>,
names: FxHashMap<Symbol, (usize, Span)>,
append_newline: bool,
) -> P<ast::Expr> {
@ -1304,6 +1309,25 @@ pub fn expand_preparsed_format_args(
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);
}
@ -1318,7 +1342,7 @@ pub fn expand_preparsed_format_args(
let mut cx = Context {
ecx,
args,
args: args.into_iter().map(|arg| arg.expr).collect(),
num_captured_args: 0,
arg_types,
arg_unique_types,