We have been using call_traits from Boost version 1.29.0 in conjunction with MSVC 7.0. When attempting to recompile this code under MSVC 7.1, using either Boost 1.29.0 or 1.30.0, we now encounter compilation errors. A simple example of the usage pattern is: class A { public: template<typename _Source> void doSomething ( typename boost::call_traits<_Source>::param_type value ) { } }; The new compiler generates the error message:
c:\Documents and Settings\rbowen\My Documents\Projects\CallTraitsTest\CallTraitsTest.cpp(34) : error C2783: 'void A::doSomething (boost::call_traits<_Source>::param_type)' : could not deduce template argument for '_Source' c:\Documents and Settings\rbowen\My Documents\Projects\CallTraitsTest\CallTraitsTest.cpp(11) : see declaration of 'A::doSomething'
As an experiment, I manually included the older logic for call_traits by cutting and pasting the relevant classes into my source from 'detail/ob_call_traits.hpp' and still encountered the same error.
Has anyone else experienced this? Is this (yet another) MS compiler bug?
No it is a correct error: call_traits can not be used in deduced contexts, sorry :-( John.