orphNamesOfCoAxBranch :: CoAxBranch -> NameSet
orphNamesOfCoAxBranch (CoAxBranch { cab_lhs = lhs, cab_rhs = rhs })
  = orphNamesOfTypes lhs `unionNameSet` orphNamesOfType rhs
orphNamesOfCoAxBranch :: CoAxBranch -> NameSet
orphNamesOfCoAxBranch (CoAxBranch { cab_lhs = lhs, cab_rhs = rhs })
  = orphNamesOfTypes lhs `unionNameSet` orphNamesOfType rhs
orphNamesOfCoAxBranch (CoAxBranch { cab_lhs = lhs, cab_rhs = rhs })
  = orphNamesOfTypes lhs `unionNameSet` orphNamesOfType rhs