{"ast_node_type":"other","tokens":[{"end":62,"kind":"keyword","start":0,"text":"self.eq_relations().probe_value(vid).is_unknown(),"}]}
            self.eq_relations().probe_value(vid).is_unknown(),
        debug_assert!(
            "instantiating type variable `{vid:?}` twice: new-value = {ty:?}, old-value={:?}",