dfa: flush only ++ unary operator arguments (IDEA-150271)

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

@@ -1667,7 +1667,7 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
   }
 
   private void flushIncrementedValue(@Nullable PsiExpression operand) {
-    if (operand instanceof PsiReferenceExpression) {
+    if (operand instanceof PsiReferenceExpression && PsiUtil.isAccessedForWriting(operand)) {
       PsiVariable psiVariable = DfaValueFactory.resolveUnqualifiedVariable((PsiReferenceExpression)operand);
       if (psiVariable != null) {
         DfaVariableValue dfaVariable = myFactory.getVarFactory().createVariableValue(psiVariable, false);

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

@@ -0,0 +1,14 @@
+import org.jetbrains.annotations.Nullable;
+
+class NullTest {
+
+  public void clear(@Nullable Integer mask) {
+    if (mask == null) {
+      return;
+    }
+
+    int i = ~mask;
+    int i2 = ~mask;
+  }
+
+}

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

@@ -431,6 +431,7 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
 
   public void testConstantConditionsWithAssignmentsInside() { doTest(); }
   public void testIfConditionsWithAssignmentInside() { doTest(); }
+  public void testBitwiseNegatedBoxed() { doTest(); }
 
   public void testLiteralIfCondition() {
     doTest();