anchor.diff:   */
   dropUserStatement returns [::shared_ptr<drop_role_statement> stmt]
       @init { bool ifExists = false; }
  -    : K_DROP K_USER (K_IF K_EXISTS { ifExists = true; })? username
  -      { $stmt = ::make_shared<drop_role_statement>(cql3::role_name($username.text, cql3::preserve_role_case::yes), ifExists); }
  +    : K_DROP K_USER (K_IF K_EXISTS { ifExists = true; })? u=username
  +      { $stmt = ::make_shared<drop_role_statement>(cql3::role_name(u, cql3::preserve_role_case::yes), ifExists); }
       ;
   
   /**
  
positive.code: 
          bool ifNotExists = false;
      }
      : K_CREATE K_USER (K_IF K_NOT K_EXISTS { ifNotExists = true; })? username
        ( K_WITH K_PASSWORD v=STRING_LITERAL { opts.password = $v.text; })?
        ( K_SUPERUSER { opts.is_superuser = true; } | K_NOSUPERUSER { opts.is_superuser = false; } )?
        { $stmt = ::make_shared<create_role_statement>(cql3::role_name($username.text, cql3::preserve_role_case::yes), std::move(opts), ifNotExists); }
      ;
  
  /**
  
negative.code:     @init {
          cql3::role_options opts;
      }
      : K_ALTER K_USER u=username
        ( K_WITH K_PASSWORD v=STRING_LITERAL { opts.password = $v.text; })?
        ( K_SUPERUSER { opts.is_superuser = true; } | K_NOSUPERUSER { opts.is_superuser = false; } )?
        { $stmt = ::make_shared<alter_role_statement>(cql3::role_name(u, cql3::preserve_role_case::yes), std::move(opts)); }
      ;
  
  /**
  