This is a collection of things that test suites have said were "wrong" with GCC--but that I don't agree with. First, test suites sometimes test for compatibility with traditional C. GCC with -traditional is not completely compatible with traditional C, and in some ways I think it should not be. * K&R C allowed \x to appear in a string literal (or character literal?) even in cases where it is *not* followed by a sequence of hex digits. I'm not convinced this is desirable. * K&R compilers allow comments to cross over an inclusion boundary (i.e. started in an include file and ended in the including file). I think this would be quite ugly and can't imagine it could be needed. Sometimes tests disagree with GCC's interpretation of the ANSI standard. * One test claims that this function should return 1. enum {A, B} foo; func (enum {B, A} arg) { return B; } I think it should return 0, because the definition of B that applies is the one in func. * Some tests report failure when the compiler does not produce an error message for a certain program. ANSI C requires a "diagnostic" message for certain kinds of invalid programs, but a warning counts as a diagnostic. If GCC produces a warning but not an error, that is correct ANSI support. When test suites call this "failure", the tests are broken.