[java-dfa] IDEA-307630 Constant values: remove warning at the beginning of |= and &= series

GitOrigin-RevId: 3841398346bfc13b26cd6bed05e51e762e2f78e1

java/java-impl-inspections/src/com/intellij/codeInspection/dataFlow/ConstantValueInspection.java

@@ -21,6 +21,7 @@ import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
+import com.intellij.psi.controlFlow.DefUseUtil;
 import com.intellij.psi.impl.source.PsiFieldImpl;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.PsiTreeUtil;
@@ -429,6 +430,10 @@ public class ConstantValueInspection extends AbstractBaseJavaLocalInspectionTool
 
     if (PsiUtil.skipParenthesizedExprUp(psiAnchor.getParent()) instanceof PsiAssignmentExpression assignment &&
         PsiTreeUtil.isAncestor(assignment.getLExpression(), psiAnchor, false)) {
+      IElementType tokenType = assignment.getOperationTokenType();
+      if (tokenType.equals(JavaTokenType.ANDEQ) || tokenType.equals(JavaTokenType.OREQ)) {
+        if (isFlagSetChain(assignment.getLExpression(), tokenType.equals(JavaTokenType.ANDEQ))) return;
+      }
       reporter.registerProblem(
         psiAnchor,
         JavaAnalysisBundle.message("dataflow.message.pointless.assignment.expression", Boolean.toString(evaluatesToTrue)),
@@ -456,6 +461,18 @@ public class ConstantValueInspection extends AbstractBaseJavaLocalInspectionTool
     reporter.registerProblem(psiAnchor, message, fixes.toArray(LocalQuickFix.EMPTY_ARRAY));
   }
 
+  private static boolean isFlagSetChain(@NotNull PsiExpression expression, boolean isAnd) {
+    PsiLocalVariable local = ExpressionUtils.resolveLocalVariable(expression);
+    if (local == null) return false;
+    PsiExpression initializer = local.getInitializer();
+    if (!ExpressionUtils.isLiteral(initializer, isAnd)) return false;
+    if (!(PsiUtil.getVariableCodeBlock(local, null) instanceof PsiCodeBlock block)) return false;
+    PsiElement[] defs = DefUseUtil.getDefs(block, local, expression.getParent());
+    // boolean x = false; x|=something;
+    return defs.length == 1 && defs[0] == local && 
+           VariableAccessUtils.getVariableReferences(local, block).stream().filter(PsiUtil::isAccessedForWriting).limit(2).count() > 1;
+  }
+
   private static @Nullable LocalQuickFix createSimplifyBooleanExpressionFix(PsiElement element, final boolean value) {
     LocalQuickFixOnPsiElement fix = createSimplifyBooleanFix(element, value);
     if (fix == null) return null;

java/java-tests/testData/inspection/dataFlow/ancient/AndEq.java

@@ -1,7 +1,7 @@
 class Test {
   public void foo(boolean x, boolean y, boolean z) {
     boolean r = true;
-    <warning descr="Condition 'r' at the left side of assignment expression is always 'true'. Can be simplified">r</warning> &= x;
+    r &= x;
     r &= y;
     r &= z;
   }

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

@@ -0,0 +1,22 @@
+// IDEA-304296
+class BooleanOrEquals {
+  boolean test() {
+    boolean result = false;
+    result |= check1();
+    result |= check2();
+    result |= check3();
+    return result;
+  }
+
+  boolean testWrong() {
+    boolean result = true;
+    <warning descr="Condition 'result' at the left side of assignment expression is always 'true'. Can be simplified">result</warning> |= check1();
+    <warning descr="Condition 'result' at the left side of assignment expression is always 'true'. Can be simplified">result</warning> |= check2();
+    <warning descr="Condition 'result' at the left side of assignment expression is always 'true'. Can be simplified">result</warning> |= check3();
+    return result;
+  }
+  
+  native boolean check1();
+  native boolean check2();
+  native boolean check3();
+}

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

@@ -722,4 +722,5 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testSuppression() { doTest(); }
   public void testRewiringSubclassMethod() { doTest(); }
   public void testTryWithResourcesCloseThrows() { doTest(); }
+  public void testBooleanOrEquals() { doTest(); }
 }