*** Process tests/ErrorDup.newt
module ErrorDup
ERROR at tests/ErrorDup.newt:5:6--5:9: Nat already declared
  data Nat = Z | S Nat
  
  data Nat = Z | S Nat
       ^^^

ERROR at tests/ErrorDup.newt:7:8--7:11: Nat already declared
  data Nat = Z | S Nat
  
  record Nat where
         ^^^

ERROR at tests/ErrorDup.newt:9:7--9:10: Nat already declared
  record Nat where
  
  class Nat where
        ^^^

Compile failed