Don't allow {} to refer to implicit captures in format_args.

This commit is contained in:
Mara Bos 2022-01-27 23:50:46 +01:00
parent 9ad5d82f82
commit 9b8e4c63de

View file

@ -23,6 +23,7 @@ enum ArgumentType {
enum Position {
Exact(usize),
Capture(usize),
Named(Symbol),
}
@ -47,6 +48,8 @@ struct Context<'a, 'b> {
/// * `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.
@ -229,6 +232,11 @@ fn parse_args<'a>(
}
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(&self, p: &mut parse::Piece<'_>) {
// NOTE: the `unwrap_or` branch is needed in case of invalid format
// arguments, e.g., `format_args!("{foo}")`.
@ -343,7 +351,7 @@ impl<'a, 'b> Context<'a, 'b> {
}
fn describe_num_args(&self) -> Cow<'_, str> {
match self.args.len() {
match self.num_args() {
0 => "no arguments were given".into(),
1 => "there is 1 argument".into(),
x => format!("there are {} arguments", x).into(),
@ -369,7 +377,7 @@ impl<'a, 'b> Context<'a, 'b> {
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.args.len() {
if self.names.is_empty() && !numbered_position_args && count != self.num_args() {
e = self.ecx.struct_span_err(
sp,
&format!(
@ -417,7 +425,7 @@ impl<'a, 'b> Context<'a, 'b> {
if let Some(span) = fmt.precision_span {
let span = self.fmtsp.from_inner(span);
match fmt.precision {
parse::CountIsParam(pos) if pos > self.args.len() => {
parse::CountIsParam(pos) if pos > self.num_args() => {
e.span_label(
span,
&format!(
@ -460,7 +468,7 @@ impl<'a, 'b> Context<'a, 'b> {
if let Some(span) = fmt.width_span {
let span = self.fmtsp.from_inner(span);
match fmt.width {
parse::CountIsParam(pos) if pos > self.args.len() => {
parse::CountIsParam(pos) if pos > self.num_args() => {
e.span_label(
span,
&format!(
@ -492,12 +500,15 @@ impl<'a, 'b> Context<'a, 'b> {
/// 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) => {
if self.args.len() <= arg {
self.invalid_refs.push((arg, self.curpiece));
return;
}
Exact(arg) | Capture(arg) => {
match ty {
Placeholder(_) => {
// record every (position, type) combination only once
@ -524,7 +535,7 @@ impl<'a, 'b> Context<'a, 'b> {
match self.names.get(&name) {
Some(&idx) => {
// Treat as positional arg.
self.verify_arg_type(Exact(idx), ty)
self.verify_arg_type(Capture(idx), ty)
}
None => {
// For the moment capturing variables from format strings expanded from macros is
@ -539,9 +550,10 @@ impl<'a, 'b> Context<'a, 'b> {
} 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);
self.verify_arg_type(Exact(idx), ty)
self.verify_arg_type(Capture(idx), ty)
} else {
let msg = format!("there is no argument named `{}`", name);
let sp = if self.is_literal {
@ -1010,6 +1022,7 @@ pub fn expand_preparsed_format_args(
let mut cx = Context {
ecx,
args,
num_captured_args: 0,
arg_types,
arg_unique_types,
names,