Regression12.dfy(82,14): Warning: the type of the other operand is a map to a non-null type, so the inclusion test of 'null' will always return 'false'
Regression12.dfy(83,14): Warning: the type of the other operand is a set of non-null elements, so the non-inclusion test of 'null' will always return 'true'
Regression12.dfy(84,14): Warning: the type of the other operand is a set of non-null elements, so the non-inclusion test of 'null' will always return 'true'
Regression12.dfy(85,14): Warning: the type of the other operand is a set of non-null elements, so the non-inclusion test of 'null' will always return 'true'
Regression12.dfy(65,7): Error: value of expression (of type 'set<Node?>') is not known to be an instance of type 'set<Node>'
Regression12.dfy(14,25): Error: value does not satisfy the subset constraints of 'int -> char' (possible cause: it may be partial or have read effects)
Regression12.dfy(16,25): Error: value does not satisfy the subset constraints of 'int -> char' (possible cause: it may be partial or have read effects)

Dafny program verifier finished with 5 verified, 3 errors
