c++ - 这个 noexcept 声明有效吗？

Question

struct X
{
    void f() noexcept(noexcept(g()));
    void g() noexcept;
};

在 vc++ 和 clang 中，这可以工作，但 gcc 会提示:

source_file.cpp:6:34: error: ‘g’ was not declared in this scope
     void f() noexcept(noexcept(g()));
                                  ^

我认为这是 gcc 中的一个错误，而不是其他 gcc 中的功能。这是正确的吗？

Answer 1

您的评估是 correct

Within the class member-specification, the class is regarded as complete within function bodies, default arguments, noexcept-specifiers, and default member initializers (including such things in nested classes). Otherwise it is regarded as incomplete within its own class member-specification.

在完整类型的范围内，g 应该由 unqualified name lookup 找到。