小编use*_*426的帖子

我有以下代码:

#include <utility>

template<class T,class E = void>
struct func_impl;

template<class T,class E = void>
constexpr inline bool has_func = false;

template<class T>
constexpr inline bool has_func<T,decltype(func_impl<T>::apply(std::declval<T>()))> = true;

template<>
struct func_impl<int>
{
   static int apply(int i);
};

static_assert(has_func<int>);

static_assert失败,我预计它会成功.我做错了什么？