c++ - 属性说明符序列是否继承？

Question

看看这个片段:

struct [[nodiscard]] Result {
};


struct DiscardableResult: Result {
};

DiscardableResult 是否有 [[nodiscard]] 属性？如果是，是否有可能以某种方式将其删除？

Answer 1

[dcl.attr.nodiscard]/2 说:

A nodiscard call is a function call expression that calls a function previously declared nodiscard, or whose return type is a possibly cv-qualified class or enumeration type marked nodiscard.

函数的返回类型是DiscardableResult。这种类型没有标记为nodiscard，定义在[dcl.attr.grammar]/5:

Each attribute-specifier-seq is said to appertain to some entity or statement, identified by the syntactic context where it appears (Clause 9, Clause 10, Clause 11). If an attribute-specifier-seq that appertains to some entity or statement contains an attribute or alignment-specifier that is not allowed to apply to that entity or statement, the program is ill-formed. If an attribute-specifier-seq appertains to a friend declaration (14.3), that declaration shall be a definition. No attribute-specifier-seq shall appertain to an explicit instantiation (17.7.2).

添加了重点。

DiscardableResult 的“句法上下文”中没有属性。因此，没有属性“属于”该实体。

属性不会被继承。