--- /dev/null
+base_null.nit:28,2--13: Warning: expression is not null, since it is a `null`.
+base_null.nit:42,2--13: Warning: expression is not null, since it is a `null`.
+false
+false
+true
+true
+
+false
+false
+true
+true
+
+true
+true
+false
+false