Yes, it's a compiler bug, but usually for the vast majority of negative tests compiler produces error messages. The problem is that those messages are irrelevant for my purpose. I need to filter them out to be focused only on false error messages from positive tests which indicate compiler bug. My goal is to find compiler bugs, not source code bugs, and I do not need negative tests for that. Concerning compiler bugs related to successful compilation of incorrect code. That type of bugs though important, but are pretty rare, and usually on earlier stages of compiler implementations, they are not first priority.
I understand all that, but remember that this is written by volunteers, and that we have no real need for what you want to do - our aim is to test source code and catch regressions, not to test compilers as such. So I'm afraid you'll probably have to patch things yourself :( How about gutting the contents of of the compile-fail rule in tools/build/src/tools/testing.jam? HTH, John.