{"ast_node_type":"variable","tokens":[{"end":80,"kind":"keyword","start":0,"text":"let"}]}
        let filler = (starting_from..).zip(other).map(|(idx, kind)| match kind {
        let other = &this.param_kinds[this.vec.len()..];
            ParamKind::Type => BoundVar::new(debruijn, idx).to_ty(Interner).cast(Interner),