}
impl<'tcx> Value<TyCtxt<'tcx>> for ty::Binder<'_, ty::FnSig<'_>> {
- fn from_cycle_error(tcx: TyCtxt<'tcx>, _: &[QueryInfo]) -> Self {
+ fn from_cycle_error(tcx: TyCtxt<'tcx>, stack: &[QueryInfo]) -> Self {
let err = tcx.ty_error();
- // FIXME(compiler-errors): It would be nice if we could get the
- // query key, so we could at least generate a fn signature that
- // has the right arity.
+
+ let arity = if let Some(frame) = stack.get(0)
+ && frame.query.name == "fn_sig"
+ && let Some(def_id) = frame.query.def_id
+ && let Some(node) = tcx.hir().get_if_local(def_id)
+ && let Some(sig) = node.fn_sig()
+ {
+ sig.decl.inputs.len() + sig.decl.implicit_self.has_implicit_self() as usize
+ } else {
+ tcx.sess.abort_if_errors();
+ unreachable!()
+ };
+
let fn_sig = ty::Binder::dummy(tcx.mk_fn_sig(
- [].into_iter(),
+ std::iter::repeat(err).take(arity),
err,
false,
rustc_hir::Unsafety::Normal,