Method rename

src/analysis/memory/nullness_domain.rs:37–43

(&mut self, old_path: &Rc<Path>, new_path: &Rc<Path>)

    }

    pub fn rename(&mut self, old_path: &Rc<Path>, new_path: &Rc<Path>) {
        if let Some(value) = self.value_map.remove(old_path) {
            self.value_map.insert(new_path.clone(), value);
        } else {
            self.value_map.remove(new_path);
        }
    }

    pub fn duplicate(&mut self, old_path: &Rc<Path>, new_path: &Rc<Path>) {
        if let Some(value) = self.value_map.get(old_path).copied() {