Hello, This is not a boost-related issue (except the fact that enable_if is used), but it might be of interest to the boost-users community. The following bug was detected in some compicated environment, but the following seems to be the minimal construct where it appears (compile in Debug mode; see comments in Test::func() ). // main.cpp #include #include class BasicVersion {}; template class Version1 : public BasicVersion { protected: Version1() : verData_(2) {} void go() { verData_ = 3; } int verData_; }; template class TestBase {}; template<typename Param> class TestBase::type> : public Version1<Param> {}; template<class Param> class Test : private boost::noncopyable, public TestBase<Param> { public: void func() { go(); // This works well TestBase::go(); // This jumps to an incorrect place (bad "this"), verData_ contains garbage /* the following code is generated for the previous 2 calls: go(); 004116D3 mov ecx,dword ptr [this] 004116D6 add ecx,4 004116D9 call Version1::go (4110F5h) TestBase::go(); 004116DE mov ecx,dword ptr [this] 004116E1 add ecx,8 004116E4 call Version1::go (4110F5h) */ } private: int data_; }; int main() { Test<int> test; test.func(); }