Re: [boost] [iterator][type_traits] A test is failing with gcc in c++03mode

On 17/12/2016 16:45, Peter Dimov wrote:

Edward Diener wrote:

...

The zip_iterator_test_std_pair is failing with gcc in c++-03 mode. The problem reduces viqa Boost type traits to the fact that in gcc c++03 mode the expression:

__is_abstract(std::pair)

where __is_abstract is a compiler intrinsic, gives an error of:

error: forming reference to reference type 'std::__cxx11::basic_string<char>&' pair(const _T1& __a, const _T2& __b) ^~~~

Is this a valid error according to the C++ 2003 standard ?

References to references were invalid in C++98, but were made conditionally valid in C++03 by

http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#106

However, __is_abstract is nonstandard, so who knows what it does. It might be worth trying -std=gnu++03 instead of -std=c++03.

I think the issue here is that you are calling __is_abstract(malformed_type) - so when the compiler instantiates std::pair to see if it's abstract or not the error gets generated. But I'm not sure that helps ;) John.