# V2018. Cast should not remove 'const' qualifier from the type that is pointed to by a pointer or a reference.

This diagnostic rule was added at users' request.

The analyzer has detected a situation where the 'const' qualifier was removed. Modifying an object, which was declared with the 'const' qualifier, through a pointer/reference to non-'const' type leads to undefined behavior. Besides, such code often indicates poor application design.

Look at the example:

    void read_settings(const char *buf);
    const char* get_settings_file_name();
    bool settings_present();
    // ....
    void init_settings()
    {
      const char name[MAX_PATH] = "default.cfg";
      if (settings_present())
      {
        strcpy((char *)name, get_settings_file_name());
      }
      read_settings(name);
    }

To avoid undefined behavior, abandon constancy when declaring a local variable:

    void read_settings(const char *buf);
    const char* get_settings_file_name();
    bool settings_present();
    // ....
    void init_settings()
    {
      char name[MAX_PATH] = "default.cfg";
      if (settings_present())
      {
        strcpy(name, get_settings_file_name());
      }
      read_settings(name);
    }