bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

suggest a positional formatting argument instead of a captured argument

Browse source
This commit is contained in:
Takayuki Maeda 2022-08-02 20:33:40 +09:00
parent e4417cf020
commit 4233a13ceb
5 changed files with 148 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

39
compiler/rustc_builtin_macros/src/format.rs
View file

@ -250,6 +250,11 @@ 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.
@ -263,8 +268,8 @@ 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);
@ -332,7 +337,7 @@ 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;
@ -344,7 +349,7 @@ 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()?;
@ -355,11 +360,11 @@ 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 });
}
}
}
@ -1180,7 +1185,7 @@ 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> {
@ -1270,6 +1275,24 @@ 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<_>>();
let mut suggestions = vec![(captured_arg_span, positional_args.len().to_string())];
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,
};
suggestions.push((span.shrink_to_hi(), format!(", {}", arg)))
}
e.multipart_suggestion_verbose(
"consider using a positional formatting argument instead",
suggestions,
Applicability::MachineApplicable,
);
}
e.emit();
return DummyResult::raw_expr(sp, true);
}
@ -1284,7 +1307,7 @@ 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,