static_assert安置問題

Question

具有：（不用擔心這個碼的長度，專注於結構X和範圍）（您可以複製和粘貼，並應編譯）：
EDITED

#include <limits.h> 
#include <type_traits> 
//This is from file "Static_limits.h" 
template<class T>struct static_numeric_limits; 
template<>struct static_numeric_limits<signed char> 
{ 
    enum {min = SCHAR_MIN,max = SCHAR_MAX}; 
}; 
/*This "surplus" template is here for the reason that char is threated diferently from signed char */ 
template<>struct static_numeric_limits<char> 
{ 
    enum {min = SCHAR_MIN,max = SCHAR_MAX}; 
}; 
template<>struct static_numeric_limits<unsigned char> 
{ 
    enum {min = 0x0,max = UCHAR_MAX}; 
}; 
template<>struct static_numeric_limits<unsigned short> 
{ 
    enum {min = 0x0,max = USHRT_MAX}; 
}; 
template<>struct static_numeric_limits<signed short> 
{ 
    enum {min = SHRT_MIN,max = SHRT_MAX}; 
}; 
template<>struct static_numeric_limits<unsigned int> 
{ 
    enum {min = 0x0,max = UINT_MAX}; 
}; 
template<>struct static_numeric_limits<signed int> 
{ 
    enum {min = INT_MIN,max = INT_MAX}; 
}; 
template<>struct static_numeric_limits<unsigned long> 
{ 
    enum {min = 0x0,max = ULONG_MAX}; 
}; 
template<>struct static_numeric_limits<signed long> 
{ 
    enum {min = LONG_MIN,max = LONG_MAX}; 
}; 
template<>struct static_numeric_limits<unsigned long long> 
{ 
    static const long long min = 0x0; 
    static const long long max = ULLONG_MAX; 
}; 
template<>struct static_numeric_limits<signed long long> 
{ 
#define LLONG_MAX  9223372036854775807LL 
    /* maximum signed long long int value */ 
    static const long long min = LLONG_MIN; 
    static const long long max = LLONG_MAX; 
}; 
//This is from main.cpp 
typedef unsigned long long uint_64; 
typedef signed long long int_64; 
/*Validates range*/ 
template<class IntType, uint_64 value_,bool C = std::is_signed<IntType>::value> 
struct validate_range; 
template<class IntType,uint_64 value_> 
struct validate_range<IntType,value_,true> 
{ 
    enum {value = (static_cast<int_64>(value_) >= static_numeric_limits<IntType>::min) && 
        (static_cast<int_64>(value_) <= static_numeric_limits<IntType>::max) 
     }; 
}; 
template<class IntType,uint_64 value_> 
struct validate_range<IntType,value_,false> 
{ 
    enum {value = (value_ >= static_numeric_limits<IntType>::min) && 
        (value_ <= static_numeric_limits<IntType>::max) 
     }; 
}; 
template<class IntType, IntType value> 
struct Range 
{ 
private: 
    const IntType value_; 
protected: 
    const IntType getRange()const 
    { 
     return value_; 
}  public: 
    Range():value_(value) 
    { 
     /*eb*/ 
    } 
    //this static assert in here won't work even though this class is a base class for Low 
    static_assert((validate_range<IntType, value>::value),"Value constant is out of range"); 
}; 
template<class IntType, IntType value> 
struct Low : private Range<IntType,value>//HERE Range IS INHERITED BY Low 
{ 
    const IntType getLowRange()const 
    { 
     return Range<IntType,value>::getRange(); 
    } 
}; 
template<typename IntType, uint_64 low_range> 
struct X : public Low<IntType,low_range> 
{}; 
    //static_assert((validate_range<IntType, Value>::value),"Value constant is out of range");//this static doesn't work if placed in Low's base class namely Range  }; 
    int main(int argc, char** argv) 
    { 
     X<unsigned char, -2> x4;//this should fail 
     return 0; 
    } 

所以基本上我在這裏問的是爲什麼static_assert（（validate_range :: value），...如果放置在Range結構中不起作用，而這又是Low的基類，而這又是X的基類，但是如果放置直接在struct X EDITED
夥計們我很抱歉爲以前的代碼。我編輯了我的文章，這次它應該可以工作（揭示真正的問題）。再一次，對上一個代碼感到抱歉，我只是不知道發生了什麼。

Answer 1

這是我得到的錯誤。他們似乎相當自我解釋：

test.cpp:115:45: error: use of undeclared identifier 'Value'; did you mean 'value'? 
    static_assert((validate_range<IntType, Value>::value),"Value constant is out of range"); 
              ^~~~~ 
              value 
test.cpp:99:37: note: 'value' declared here 
    template<class IntType, IntType value> 
            ^
test.cpp:127:39: error: use of undeclared identifier 'low_range' 
     struct X : public Low<IntType,low_range> 
            ^
test.cpp:128:9: error: expected class name 
     { 
     ^
3 errors generated. 

編輯

的最新文章編譯爲我（除了重新界定LLONG_MAX警告）。