c++ - 涉及 "using"别名的成员函数重载解析中的英特尔 C++ 编译器错误？

Question

#include <cstddef>

template<typename T, T... Is>
struct Bar { };

template<size_t... Is>
using Baz = Bar<size_t, Is...>;

struct Foo {
  template<size_t... Is>
  void NoAlias(Bar<size_t, Is...>) { }

  template<size_t... Is>
  void Alias(Baz<Is...>) { }
};

template<typename T, T... Is>
void foo(Bar<T, Is...>) { }

template<size_t... Is>
void bar(Bar<size_t, Is...>) { }

int main() {
  // All these work fine
  foo(Bar<size_t, 4, 2>());
  foo(Baz<4, 2>());
  bar(Bar<size_t, 4, 2>());
  bar(Baz<4, 2>());
  Foo().NoAlias(Bar<size_t, 4, 2>());
  Foo().NoAlias(Baz<4, 2>());

  // But these two give error on ICPC (ICC) 14.0.2:
  //   no instance of function template "Foo::Alias" matches the argument list
  // Note the only difference between NoAlias and Alias is (not) using the alias
  // for the member function parameter
  Foo().Alias(Bar<size_t, 4, 2>());
  Foo().Alias(Baz<4, 2>());

  return 0;
}

ICC 14.0.2 报错:

$ icc -std=c++11 -Wall -pedantic -pthread -o .scratch{-,.}cpp && ./.scratch-cpp

.scratch.cpp(36): error: no instance of function template "Foo::Alias" matches the argument list
            argument types are: (Bar<size_t, 4UL, 2UL>)
            object type is: Foo
    Foo().Alias(Bar<size_t, 4, 2>());
          ^

.scratch.cpp(37): error: no instance of function template "Foo::Alias" matches the argument list
            argument types are: (Baz<4UL, 2UL>)
            object type is: Foo
    Foo().Alias(Baz<4, 2>());
          ^

但是，它可以与 GCC 4.8 和 Clang 3.4.2 一起编译。 (在 64 位 Linux 上测试。)

任何熟悉 C++11 标准的人都可以确认这确实是一个错误吗？

另外，是否有基于预处理器的简单解决方法？

Answer 1

您的示例(显然)格式正确。 §14.8.2.5/9 描述了在这种情况下如何执行扣除。

If P has a form that contains <T> or <i>, then each argument P_i of the respective template argument list P is compared with the corresponding argument A_i of the corresponding template argument list of A. […]. If P_i is a pack expansion, then the pattern of P_i is compared with each remaining argument in the template argument list of A. Each comparison deduces template arguments for subsequent positions in the template parameter packs expanded by P_i.

此外，您的代码正在我的机器上使用 15.0.3 版本进行编译。因此升级编译器应该可以解决这个问题。我看不到另一个简单的解决方法。