{"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
    let ty1_with_vars = vars.apply(tys.value.0.clone(), Interner);
    let vars = table.fresh_subst(tys.binders.as_slice(Interner));
    let ty2_with_vars = vars.apply(tys.value.1.clone(), Interner);