Hi Terje, I had a look at your library proposal today. Looks like a very valuable tool for everyone into generic programming. It seems quite easy to add new concepts, which I think is one of the most important things (the has_member family looks very promising). I was able to build the operator_traits test with GCC 3.2.3 mingw (about 20 minutes PIII,600MHz,512MB RAM - 100% passed - guess I just had to see it with my own eyes ;+). It failed to build on MSVC 13.10.3077 and Borland 5.4.6 (I kept the output, in case you are interested). It might be possible to put the prefiltering stage of the operator traits into sort of table based form, making it easier to maintain, eliminating a lot of inclusion dependencies and template instantiations and covering tests for builtin operators (if they should be detected, that is) as well. This can probably be done with a technique in some way similar to the one applied to the operator checking itself - defining a rule set of overloaded functions to match the exclusions. Classes with a converting copy constructor can be used to categorize the types matched by the rules. The rule sets for different operator categories could be put into nested namespaces so inner categories could 'inherit' the rules of the outter ones. I attached some experimental source code for the prefiltering of an operator+ check to clearify the basic idea (compiles with GCC and MSVC and CVS version of boost). However, I am looking forward to using your library. It's late here now - so that's it for today. Best regards, Tobias