Re: [boost] [Review] Boost.Type Traits Extension by Frederic Bron

Subject: Re: [boost] [Review] Boost.Type Traits Extension by Frederic Bron
From: Jeffrey Lee Hellrung, Jr. (jhellrung_at_[hidden])
Date: 2011-03-17 13:17:23

On 3/17/2011 7:17 AM, Joachim Faulhaber wrote:
> 2011/3/17 Joachim Faulhaber<afojgo_at_[hidden]>:
[...]
>> thank you again for implementing this has_operator extension. I've
>> found some problems. In the ICL I have an operator +
[...]
> template<class Type>
> inline typename enable_if
> <is_associative_element_container<Type>, Type>::type
> operator + (Type object, const Type&  operand);
>
>>
>> and is seems that more overloads are checked valid as actually exist.
>> Is this intentional?
>>
>> BOOST_AUTO_TEST_CASE(has_op_extension_qualifiers)
>> {
>> typedef int T;
>> typedef interval_set<T>               IntervalSetT;
>> typedef IntervalSetT::interval_type IntervalT;
>>
>> // This is supposed to succeed
>> BOOST_CHECK((has_operator_plus<IntervalSetT, const IntervalSetT&,
>> IntervalSetT>::value));
>>
>> BOOST_CHECK((!is_convertible<const IntervalSetT&, IntervalSetT&>::value));
>>
>> // These are supposed to fail, but they succeed
>> BOOST_CHECK((has_operator_plus<IntervalSetT, IntervalSetT&,
>> IntervalSetT>::value));
>> BOOST_CHECK((has_operator_plus<IntervalSetT, IntervalSetT,
>> IntervalSetT>::value));
>> BOOST_CHECK((has_operator_plus<IntervalSetT, IntervalSetT,
>> IntervalSetT const&>::value));
>> }

An operator trait allows implicit conversions in the arguments.  In 
fact, the current implementation strategy *must* allow implicit 
conversions in the arguments, i.e., I wouldn't know how to detect 
*exact* signatures.

- Jeff