__gnu_debug::__check_dereferenceable bug ?

[Daniel Krügler]

2013/10/18 François Dumont <frs.dumont@gmail.com>:
> Available overloads are:
>
>   template<typename _Iterator>
>     inline bool
>     __check_dereferenceable(_Iterator&)
>     { return true; }
>
>   template<typename _Tp>
>     inline bool
>     __check_dereferenceable(const _Tp* __ptr)
>     { return __ptr; }
>
>   template<typename _Iterator, typename _Sequence>
>     inline bool
>     __check_dereferenceable(const _Safe_iterator<_Iterator, _Sequence>& __x)
>     { return __x._M_dereferenceable(); }
>
>
>     I don't understand why the compiler is choosing the 1st overload when
> passing an lvalue rather than the 3rd, is it normal ?

Yes, this is normal. This is similar to the preference of a
copy-constructor-like template over the copy constructor for non-const
values such as in

struct S {
  S();
  template<class T>
  S(T&);
} s1;

S s2(s1) // Selects the member template, not the copy constructor

> If so, it is ok to patch the library to take a const reference in the 1st overload ?

I believe so, yes.

- Daniel