disable constant value warnings in complex assignments (IDEA-111478)

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

@@ -1673,7 +1673,8 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
       addInstruction(expression.resolve() instanceof PsiField ? new FieldReferenceInstruction(expression, null) : new PopInstruction());
     }
 
-    addInstruction(new PushInstruction(getExpressionDfaValue(expression), expression, PsiUtil.isAccessedForReading(expression)));
+    boolean referenceRead = PsiUtil.isAccessedForReading(expression) && !PsiUtil.isAccessedForWriting(expression);
+    addInstruction(new PushInstruction(getExpressionDfaValue(expression), expression, referenceRead));
 
     finishElement(expression);
   }

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

@@ -0,0 +1,6 @@
+class Test {
+  void foo() {
+    int x = 42;
+    <caret>x += 100;
+  }
+}

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

@@ -175,6 +175,11 @@ public class DataFlowInspectionTest extends LightCodeInsightFixtureTestCase {
     myFixture.launchAction(myFixture.findSingleIntention("Replace with 'FOO'"));
     myFixture.checkResultByFile(getTestName(false) + "_after.java");
   }
+  public void testReportConstantReferences_NotInComplexAssignment() {
+    myFixture.addClass("package foo; public enum MyEnum { FOO }");
+    doTestReplaceConstantReferences();
+    assertEmpty(myFixture.filterAvailableIntentions("Replace with"));
+  }
   public void testReportConstantReferences_Switch() { doTestReplaceConstantReferences(); }
 
   public void testCheckFieldInitializers() {