1/1: Building ConstructorDuplicate (ConstructorDuplicate.idr)
Error: Main.B is already defined.

ConstructorDuplicate.idr:1:14--1:15
   |
 1 | data A = B | B
   |              ^

Error: Main.D is already defined.

ConstructorDuplicate.idr:5:3--5:15
   |
 5 |   D : C String
   |   ^^^^^^^^^^^^