Re: [boost] [type_erasure]any(const binding<Concept>&, ...) compile error

Subject: Re: [boost] [type_erasure]any(const binding<Concept>&, ...) compile error
From: Larry Evans (cppljevans_at_[hidden])
Date: 2012-07-26 10:40:52

On 07/26/12 09:02, Steven Watanabe wrote:
> AMDG
> 
> On 07/26/2012 05:29 AM, Larry Evans wrote:
>> The attached, when compiled with with gcc4.8-20120624,
>> produces compile error:
>>
>> ../../../boost/type_erasure/detail/construct.hpp: In instantiation of
>> 'boost::type_erasure::any<Concept, T>::any(const
>> boost::type_erasure::binding<Concept>&, U0&) [with U0 =
>> value<boost::type_erasure::_a>; Concept =
>> boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_a>,
>> boost::type_erasure::copy_constructible<boost::type_erasure::_b> >; T =
>> boost::type_erasure::_a]':
>> binding_of.cpp:71:32:   required from here
>> ../../../boost/type_erasure/detail/construct.hpp:99:9: error: invalid
>> use of void expression
>>          )
>>          ^
>>
>> Am I doing something wrong?
>>
> 
> The concept doesn't contain anything that
> matches an argument of type value<_a>.
> 
Then why isn't a similar compile error produced when b_any is constructed?

A revised test driver(attached) uses double instead of
value<_a> and value<_b> and it still produces the same error.

In addition, when bindings_made instead of b_bindings is used to
make a_any, it compiles and runs without problem whether
value<_a> or value<_a>::type (i.e. double) is used as the
value arg to AnyA.

-regards,
Larry