function tsStruct (registry: Registry, definitions: Record<string, ModuleTypes>, { lookupIndex, name: structName, sub }: TypeDef, imports: TypeImports): string {
  setImports(definitions, imports, ['Struct']);

  const keys = (sub as TypeDef[]).map((def): string => {
    const fmtType = def.lookupName && def.name !== def.lookupName