tidyRules env (rule : rules)
  = tidyRule env rule           =: \ rule ->
    tidyRules env rules         =: \ rules ->
    (rule : rules)
tidyRules env (rule : rules)
  = tidyRule env rule           =: \ rule ->
    tidyRules env rules         =: \ rules ->
    (rule : rules)
tidyRules env (rule : rules)
  = tidyRule env rule           =: \ rule ->
    tidyRules env rules         =: \ rules ->
    (rule : rules)