On Monday 26 Sep 2005 Darren Cook <darren@dcook.org> wrote:
Has anyone had trouble with complex template code when moving from gcc 3.4 to gcc 4.0.1? I don't see anything in the release notes that matches the problem I'm getting, which looks like this (fuller error message attached below):
no matching function for call to
boost::smart_assert::Private::smart_assert_alloc<boost::smart_assert::assert_context_func>::destroy(std::pair<const
int, boost::smart_assert::assert_context_func>*)
candidates are: void __gnu_cxx::__mt_alloc_base<_Tp>::destroy(_Tp*) [with _Tp = boost::smart_assert::assert_context_func]
Darren, I didn't look in detail at your code. There is however a very significant change in how GCC determines template ambiguity that was introduced between gcc-4.0.0 and gcc-4.0.1 Have a look at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12536 This changes the handling of template partial ordering to be compatible with C++ standard DR214. I'm not sure that it might not have introduced some other side effects. To determine this I would have to understand what the new text of the standard (with DR214) specifies. And this is not so easy :-) A the moment I have a test case as a candidate for a GCC bug report. // Effect of DR214 FIX (Bug 19203) on 2 simple function template cases template <class E> class expression { }; // ef - deduction of E is via expression template<class E> void ef (expression<E> e); template<class R, class E> void ef (expression<E> e); // sf - deduction of S is simple template<class S> void sf (S s); template<class R, class S> void sf (S s); void test() { expression<int> a; ef (a); // ok ef<char> (a); // ok ef<int> (a); // Ambiguous in 4.0.1 when R == E sf (a); // ok sf<char> (a); // ok sf<int> (a); // unambiguous } I believe there is nothing fundementaly different in deducing the two forms of template parameters 'expression<E>' OR 'S'. All the best, Michael Stevens