Error: Infinite descent in the definition of type U1 in file recursive_unions.dl at line 12
.type U1 = U2 | U3
^------------------
Error: Infinite descent in the definition of type U2 in file recursive_unions.dl at line 13
.type U2 = U1 | U3
^------------------
Error: Infinite descent in the definition of type V1 in file recursive_unions.dl at line 16
.type V1 = V1 | symbol
^----------------------
Error: Infinite descent in the definition of type R in file recursive_unions.dl at line 19
.type R = R
^-----------
Error: Infinite descent in the definition of type B in file recursive_unions.dl at line 25
.type B = C | a
^---------------
Error: Infinite descent in the definition of type a in file recursive_unions.dl at line 26
.type a = D
^-----------
Error: Infinite descent in the definition of type D in file recursive_unions.dl at line 27
.type D = B | C
^---------------
7 errors generated, evaluation aborted
