On Wed, 2013-03-20 at 11:27 +0100, Matěj Cepl wrote: Thanks for trying it. It looks like the non-cpychecker tests are (mostly) passing, but every test of cpychecker is failing with: error: invalid flag "WITH_CPYCHECKER_RETURNS_BORROWED_REF_ATTRIBUTE" in line directive warning: extra tokens at end of ## directive [enabled by default] cpychecker tries to do the equivalent of -DWITH_CPYCHECKER_RETURNS_BORROWED_REF_ATTRIBUTE when it runs, via gcc.define_macro() (see libcpychecker/atttributes.py), so it looks like something to do with this is going wrong. The symptoms looks like: https://fedorahosted.org/gcc-python-plugin/ticket/41 which seemed to be a bad interaction with ccache. Are you using ccache? BTW, what exact version of gcc are you using? Thanks Dave