dfa: support outer class fields access with qualified this

more test samples

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

@@ -1,6 +1,9 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.lang.Override;
+import java.lang.Runnable;
+
 class TestInspection {
 
   private static class StringWrapper {
@@ -45,17 +48,3 @@ class TestInspection {
   }
 }
 
-class WithInner {
-  @Nullable Object o;
-
-  {
-    new Runnable() {
-      @Override
-      public void run() {
-        if (WithInner.this.o != null) {
-          System.out.println(WithInner.this.o.toString());
-        }
-      }
-    };
-  }
-}

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

@@ -0,0 +1,40 @@
+import org.jetbrains.annotations.Nullable;
+
+class WithInner extends SomeSuper {
+  @Nullable Object o;
+
+  {
+    new Runnable() {
+      @Override
+      public void run() {
+        if (WithInner.this.o != null) {
+          System.out.println(WithInner.this.o.toString());
+        }
+      }
+    };
+  }
+}
+
+class SomeSuper {
+  @Nullable Object o2;
+}
+
+class Impl1 extends SomeSuper {
+  class Impl2 extends SomeSuper {
+    {
+      new Runnable() {
+        @Override
+        public void run() {
+          if (Impl1.this.o2 != null) {
+            System.out.println(<warning descr="Method invocation 'Impl2.this.o2.hashCode()' may produce 'java.lang.NullPointerException'">Impl2.this.o2.hashCode()</warning>);
+          }
+        }
+      };
+
+      SomeSuper s = Impl1.this;
+      if (s.o2 != null) {
+        System.out.println(s.o2.toString());
+      }
+    }
+  }
+}

java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java

@@ -107,6 +107,7 @@ public class DataFlowInspectionTest extends LightCodeInsightFixtureTestCase {
   public void testAccessorPlusMutator() throws Throwable { doTest(); }
   public void testClosureVariableField() throws Throwable { doTest(); }
   public void testOptionalThis() { doTest(); }
+  public void testQualifiedThis() { doTest(); }
 
   public void testAssigningNullableToNotNull() throws Throwable { doTest(); }
   public void testAssigningUnknownToNullable() throws Throwable { doTest(); }