}
}
+// SnapshotParser is used to create a snapshot of the parser
+// without causing duplicate errors being emitted when the `Parser`
+// is dropped.
pub(super) struct SnapshotParser<'a> {
parser: Parser<'a>,
unclosed_delims: Vec<UnmatchedBrace>,
&self.sess.span_diagnostic
}
- pub(super) fn restore(&mut self, snapshot: SnapshotParser<'a>) {
+ /// Relace `self` with `snapshot.parser` and extend `unclosed_delims` with `snapshot.unclosed_delims`.
+ /// This is to avoid losing unclosed delims errors `create_snapshot_for_diagnostic` clears.
+ pub(super) fn restore_snapshot(&mut self, snapshot: SnapshotParser<'a>) {
*self = snapshot.parser;
self.unclosed_delims.extend(snapshot.unclosed_delims.clone());
}
- pub(super) fn diagnostic_snapshot(&self) -> SnapshotParser<'a> {
+ /// Create a snapshot of the `Parser`.
+ pub(super) fn create_snapshot_for_diagnostic(&self) -> SnapshotParser<'a> {
let mut snapshot = self.clone();
let unclosed_delims = self.unclosed_delims.clone();
- // initialize unclosed_delims to avoid duplicate errors.
+ // Clear `unclosed_delims` in snapshot to avoid
+ // duplicate errors being emitted when the `Parser`
+ // is dropped (which may or may not happen, depending
+ // if the parsing the snapshot is created for is successful)
snapshot.unclosed_delims.clear();
SnapshotParser { parser: snapshot, unclosed_delims }
}
} else if self.check_type() {
// Parse type argument.
let is_const_fn = self.look_ahead(1, |t| t.kind == token::OpenDelim(token::Paren));
- let mut snapshot = self.diagnostic_snapshot();
+ let mut snapshot = self.create_snapshot_for_diagnostic();
match self.parse_ty() {
Ok(ty) => GenericArg::Type(ty),
Err(err) => {
if is_const_fn {
if let Ok(expr) = (*snapshot).parse_expr_res(Restrictions::CONST_EXPR, None)
{
- self.restore(snapshot);
+ self.restore_snapshot(snapshot);
return Ok(Some(self.dummy_const_arg_needs_braces(err, expr.span)));
}
}