Actually, C++ syntax is so complex that you cannot use parser generators to parse it as it's grammar is not context-free. There are even some informal proofs that C++'s syntax is undecidable (as is Perl's and Common Lisp's, where it's obvious).
C++ semantics is completely another can of worms.
Visual Studio has barely implemented a rename refactor into their flagship C++ IDE. Last time I checked, it was still in a sort of 'beta / try at your own risk' stage. Compared to this, IntelliJ IDEA is light years ahead.
Are you sure you don't mean semantically difficult. With the exception of a few dark corners (meta programming, function pointers) the syntax is basically the same as another language. Learning that && denotes an rvalue reference is easy. Trying to understand what that means though is a lot more difficult