text: // @flow
  
  
  export type ROE = $ReadOnly<$Exact<{ f: string }>>;
  declare var roe: ROE;
  
  export const x = { ...roe, f: 1 };
  
  declare var t: null | { a: number };
  export const y = { ...t };
  
  declare var o: { f: string } | {...};
  
  export const z = {
    // $FlowExpectedError[exponential-spread]
    ...o, ...o
  };
  