dfa: overriding @NotNull has precedence over super method @Nullable

java/java-tests/testData/inspection/dataFlow/fixture/NotNullOverridesNullable.java

@@ -0,0 +1,26 @@
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.Object;
+import java.lang.Override;
+
+class Super {
+  @Nullable Object foo() {
+    return null;
+  }
+}
+
+class Main extends Super {
+  @NotNull
+  @Override
+  Object foo() {
+    return 2;
+  }
+
+  void bar(@NotNull Object o) {}
+
+  void goo() {
+    bar(foo());
+  }
+
+}