title: How VisitNamedDecl and VisitCXXRecordDecl are called by RecursiveASTVisitor?
body: <p>In <code>RecursiveASTVisitor</code>s <a href="https://clang.llvm.org/doxygen/classclang_1_1RecursiveASTVisitor.html" rel="nofollow noreferrer">doc</a>, there is are no virtual methods of name VisitNamedDecl, VisitCXXRecordDecl ..etc.
  So how they are called automatically called ?</p>