{"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"(Is)"}]}
    (Is)             => { exp!(@sym, is,              SymIs) };
    (Inout)          => { exp!(@sym, inout,           SymInout) };
    (Label)          => { exp!(@sym, label,           SymLabel) };