c++11 - Clang 提示 "cannot override a deleted function"而没有删除任何功能

Question

在以下简单的代码片段中:

#include <cstddef>

struct B
{
  virtual ~B() = default;
  static void operator delete(void *, int);
  static void * operator new(size_t, int);
};

struct C : B
{
  virtual ~C() = default;
};

clang 3.7 提示“未删除的函数 '~C' 无法覆盖已删除的函数”:
http://goo.gl/Ax6oth

Visual Studio 和 GCC 都不报告此代码中的错误。这是 clang 缺陷还是什么？

Answer 1

static void operator delete(void *, int);

不，它是

 static void operator delete(void *, std::size_t);

并且这种类型差异会导致相关的歧义:
cppreference.com has

The implicitly-declared or defaulted destructor for class T isundefined (until C++11)defined as deleted (since C++11) if any of thefollowing is true:

[...]

The implicitly-declared destructor is virtual (because the base classhas a virtual destructor) and the lookup for the deallocationfunction (operator delete() results in a call to ambiguous, deleted,or inaccessible function.

在标准(n4140 草案)§12.4 中，

5 A defaulted destructor for a class X is defined as deleted if:

[...]

(5.3) or, for a virtual destructor, lookup of the non-arraydeallocation function results in an ambiguity or in a function that isdeleted or inaccessible from the defaulted destructor.