IDEA-151355 Wrong 'condition always false' after using decrement on object field

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

@@ -1667,14 +1667,11 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
   }
 
   private void flushIncrementedValue(@Nullable PsiExpression operand) {
-    if (operand instanceof PsiReferenceExpression && PsiUtil.isAccessedForWriting(operand)) {
-      PsiVariable psiVariable = DfaValueFactory.resolveUnqualifiedVariable((PsiReferenceExpression)operand);
-      if (psiVariable != null) {
-        DfaVariableValue dfaVariable = myFactory.getVarFactory().createVariableValue(psiVariable, false);
-        addInstruction(new FlushVariableInstruction(dfaVariable));
-        if (psiVariable instanceof PsiField) {
-          addInstruction(new FlushVariableInstruction(null));
-        }
+    DfaValue dfaVariable = operand == null ? null : myFactory.createValue(operand);
+    if (dfaVariable instanceof DfaVariableValue && PsiUtil.isAccessedForWriting(operand)) {
+      addInstruction(new FlushVariableInstruction((DfaVariableValue)dfaVariable));
+      if (((DfaVariableValue)dfaVariable).getPsiVariable() instanceof PsiField) {
+        addInstruction(new FlushVariableInstruction(null));
       }
     }
   }

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

@@ -0,0 +1,12 @@
+class Test {
+  public class Node{
+    private int var;
+  }
+  public void foo(Node n){
+    assert(n.var>0);
+    n.var--;
+    if(n.var==0) { // condition always false
+      System.out.println();
+    }
+  }
+}

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

@@ -238,6 +238,7 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testLongCircuitOperations() { doTest(); }
   public void testUnconditionalForLoop() { doTest(); }
   public void testIncrementParenthesized() { doTest(); }
+  public void testDecrementAnotherObjectField() { doTest(); }
   public void testAnonymousMethodIndependence() { doTest(); }
   public void testAnonymousFieldIndependence() { doTest(); }
   public void testNoConfusionWithAnonymousConstantInitializer() { doTest(); }