------------  Case alternatives  --------------
tidyAlt :: CoreBndr -> TidyEnv -> CoreAlt -> CoreAlt
tidyAlt _case_bndr env (con, vs, rhs)
  = tidyBndrs env vs    =: \ (env', vs) ->
    (con, vs, tidyExpr env' rhs)
tidyAlt :: CoreBndr -> TidyEnv -> CoreAlt -> CoreAlt
tidyAlt _case_bndr env (con, vs, rhs)
  = tidyBndrs env vs    =: \ (env', vs) ->
    (con, vs, tidyExpr env' rhs)
tidyAlt _case_bndr env (con, vs, rhs)
  = tidyBndrs env vs    =: \ (env', vs) ->
    (con, vs, tidyExpr env' rhs)