Fix PR#22600: Wrong return type for operator() of "diamond functors"

[mclow.lists]

Summary

Make some simple C++ code much more complicated.
As a bonus, add noexcept specifications to all the 'diamond functors'

Fixes http://llvm.org/bugs/show_bug.cgi?id=22600

[EricWF]

Why not just use decltype(auto)? Also these functions not SFINAE instead of being a hard compile error when they are not well formed. is that intended?

[EricWF]

Should have read the bug report. I'll look into the SFINAE before I'm convinced that libstdc++ is correct. Do you have a strong opinion in this?

[mclow.lists]

I'm convinced that our implementation is not correct (does not match what's in the standard, and the difference is detectible).

I have no opinion about libstdc++'s implementation.

include/functional

525

This is an inadvertent change.

[EricWF]

I think the change for logical_not and bit_not are missing.

[mclow.lists]

Add logical_not and bit_not

[EricWF]

LGTM.

[EricWF]

Fixed in revision 230484.

include/__functional_base

     template <class _T1, class _T2> 
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) < _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) < _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) < _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) < _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

include/functional

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _Tp>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_Tp&& __x) const
-        { return -_VSTD::forward<_Tp>(__x); }
+    _NOEXCEPT_(noexcept(- _VSTD::forward<_Tp>(__x)))
+    -> decltype        (- _VSTD::forward<_Tp>(__x))
+        { return        - _VSTD::forward<_Tp>(__x); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _Tp>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_Tp&& __x) const
-        { return !_VSTD::forward<_Tp>(__x); }
+    _NOEXCEPT_(noexcept(!_VSTD::forward<_Tp>(__x)))
+    -> decltype        (!_VSTD::forward<_Tp>(__x))
+        { return        !_VSTD::forward<_Tp>(__x); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _T1, class _T2>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_T1&& __t, _T2&& __u) const
-        { return _VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u); }
+    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u)))
+    -> decltype        (_VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u))
+        { return        _VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u); }
     typedef void is_transparent;
 };
 #endif

     template <class _Tp>
     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
     auto operator()(_Tp&& __x) const
-        { return ~_VSTD::forward<_Tp>(__x); }
+    _NOEXCEPT_(noexcept(~_VSTD::forward<_Tp>(__x)))
+    -> decltype        (~_VSTD::forward<_Tp>(__x))
+        { return        ~_VSTD::forward<_Tp>(__x); }
     typedef void is_transparent;
 };
 #endif