c++ - 具有继承的嵌套类的名称查找

Question

这是否保证有效:

struct A
{
  struct Gold {};
};

struct B : public A
{
  typedef Gold BaseGold;
  struct Gold {};
};

struct C : public B
{
  typedef Gold BaseGold;
  struct Gold {};
};

static_assert(is_same<B::BaseGold, A::Gold>::value, "Not the right treasure!");
static_assert(is_same<C::BaseGold, B::Gold>::value, "Not the right treasure!");

它似乎适用于 VS2010。显然它依赖于微妙的声明顺序/名称查找规则，所以我想知道标准对此事的看法......

Answer 1

未定义的行为。

3.3.7/1

The following rules describe the scope of names declared in classes:

2) A name N used in a class S shall refer to the same declaration in its context and when re-evaluated in the completed scope of S. No diagnostic is required for a violation of this rule.