tfHeadedErr :: InjErrorBuilder -> CoAxBranch
            -> (SDoc, SrcSpan)
tfHeadedErr errorBuilder famInst
  = errorBuilder (injectivityErrorHerald True $$
                  text "RHS of injective type family equation cannot" <+>
                  text "be a type family:") [famInst]
tfHeadedErr :: InjErrorBuilder -> CoAxBranch
            -> (SDoc, SrcSpan)
tfHeadedErr errorBuilder famInst
  = errorBuilder (injectivityErrorHerald True $$
                  text "RHS of injective type family equation cannot" <+>
                  text "be a type family:") [famInst]
tfHeadedErr errorBuilder famInst
  = errorBuilder (injectivityErrorHerald True $$
                  text "RHS of injective type family equation cannot" <+>
                  text "be a type family:") [famInst]