Converting between function and methods

First implement your free function in terms of the member function you want to call.

bool StartsWith(std::string_view s, std::string_view prefix) {
  return s.starts_with(prefix);
}

Now annotate the old function to be inlined.

BRONTO_INLINE()
bool StartsWith(std::string_view s, std::string_view prefix) {
  return s.starts_with(prefix);
}

Sit back while Bronto switches all the callers to the member function.

After Bronto has migrated all calls to StartsWith, you can simply delete it.

First implement your method in terms of the free function you want to replace it with.

struct Pet;

void FeedPet(const Pet& p, int food_type);

struct Pet {
  void Feed() const {
    FeedPet(*this, PreferedFood());
  }

  int PreferedFood() const;
};

Now annotate the old function to be inlined.

struct Pet;

void FeedPet(const Pet& p, int food_type);

struct Pet {
  BRONTO_INLINE()
  void Feed() const {
    FeedPet(*this, PreferedFood());
  }

  int PreferedFood() const;
};

Sit back while Bronto switches all the callers to the free function.

After Bronto has migrated all calls to FeedPet, you can simply delete Pet::Feed.