1
b
b
b
b
2
a
b
b
Instance of A is not a B.
3
b
4
Instance b is not a B (it is null)
Instance a is not a nullable B
5
Instance of A is not a B.
Instance of B is null
6
1111
2222
1111
2222
3333
7
a
5555
Instance o is not a Int
5555
Instance ni is not a Int
8