unassigned reference
常见例句
- When a struct contains a reference type as a member, the default constructor of the member must be invoked explicitly, otherwise the member remains unassigned and the struct cannot be used.
当结构包含引用类型作为成员时，必须显式调用该成员的默认构造函数，否则该成员将保持未赋值状态且该结构不可用。 返回 unassigned reference