Error: Atom's argument type is not a subtype of its declared type in file type_system12.dl at line 38
C(x) :- B(x).                      // Error
--^-----------------------------------------
The argument's declared type is S1 in file type_system12.dl at line 37
.decl C(x : S1)
------------^---
Error: Atom's argument type is not a subtype of its declared type in file type_system12.dl at line 39
C(x) :- !A(x), B(x).               // Error
--^-----------------------------------------
The argument's declared type is S1 in file type_system12.dl at line 37
.decl C(x : S1)
------------^---
2 errors generated, evaluation aborted
