gecko-dev/xpcom/tests/static-checker/override-pass.cpp

class A
{
  int a(int, char*);
  void c(char);
  virtual void d(int) = 0;
};

class B : A
{
  __attribute__((user("NS_override"))) int a(int, char*);
};

class C : B
{
  __attribute__((user("NS_override"))) void c(char);
};

class D : A
{
  __attribute__((user("NS_override"))) void d(int);
};