DfaMemoryStateImpl: fix possible ClassCastException

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java

@@ -235,7 +235,10 @@ public class DfaMemoryStateImpl implements DfaMemoryState {
       setVariableState(var, state.withFacts(facts));
       SpecialFieldValue specialFieldValue = facts.get(DfaFactType.SPECIAL_FIELD_VALUE);
       if (specialFieldValue != null) {
-        setVarValue((DfaVariableValue)specialFieldValue.getField().createValue(myFactory, var), specialFieldValue.toConstant(myFactory));
+        DfaValue targetSpecialField = specialFieldValue.getField().createValue(myFactory, var);
+        if (targetSpecialField instanceof DfaVariableValue) {
+          setVarValue((DfaVariableValue)targetSpecialField, specialFieldValue.toConstant(myFactory));
+        }
       }
     }
     else if (DfaUtil.isComparedByEquals(value.getType()) && !DfaUtil.isComparedByEquals(var.getType())) {

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

@@ -0,0 +1,7 @@
+final class MyClass {
+  static final int[] arr = {1,2,3};
+  
+  void test() {
+    <error descr="Cannot assign a value to final variable 'arr'">arr</error> = new int[] {4};
+  }
+}

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

@@ -670,4 +670,5 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testNotNullAnonymousConstructor() { doTest(); }
   public void testCaughtNPE() { doTest(); }
   public void testTernaryNullability() { doTest(); }
+  public void testRewriteFinal() { doTest(); }
 }