alt/base_as_notnull_alt7.nit:42,6--7: Warning: expression is not null, since it is a `A`.
alt/base_as_notnull_alt7.nit:43,6: Warning: expression is not null, since it is a `B`.
alt/base_as_notnull_alt7.nit:52,6: Warning: expression is not null, since it is a `B`.
-alt/base_as_notnull_alt7.nit:61,1--17: Type error: as(not null) on null
+alt/base_as_notnull_alt7.nit:61,1--4: Warning: expression is always `null`.
+alt/base_as_notnull_alt7.nit:61,1--17: Type Error: `as(not null)` on `null`.