IDEA-143315 Suppress zero test extracted; suppress method call result if all args are constants

Review ID: IDEA-CR-60202

GitOrigin-RevId: 278d64a98d03fb9f9f2456e8cf8212b969c7d4de

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

@@ -40,6 +40,7 @@ import javax.swing.*;
 import java.text.MessageFormat;
 import java.util.*;
 import java.util.function.Consumer;
+import java.util.stream.Stream;
 
 import static com.intellij.util.ObjectUtils.tryCast;
 
@@ -454,23 +455,36 @@ public abstract class DataFlowInspectionBase extends AbstractBaseJavaLocalInspec
   }
 
   private static boolean shouldReportZero(PsiExpression ref) {
-    boolean reportZeroValue = ref instanceof PsiPolyadicExpression && !PsiUtil.isConstantExpression(ref) ||
-                              ref instanceof PsiMethodCallExpression;
-    if (!reportZeroValue) return false;
+    if (ref instanceof PsiPolyadicExpression) {
+      if (PsiUtil.isConstantExpression(ref)) return false;
+      PsiPolyadicExpression polyadic = (PsiPolyadicExpression)ref;
+      IElementType tokenType = polyadic.getOperationTokenType();
+      if (tokenType.equals(JavaTokenType.ASTERISK)) {
+        PsiMethod method = PsiTreeUtil.getParentOfType(ref, PsiMethod.class, true, PsiLambdaExpression.class, PsiClass.class);
+        if (MethodUtils.isHashCode(method)) {
+          // Standard hashCode template generates int result = 0; result = result * 31 + ...;
+          // so annoying warnings might be produced there
+          return false;
+        }
+      }
+    }
+    else if (ref instanceof PsiMethodCallExpression) {
+      PsiMethodCallExpression call = (PsiMethodCallExpression)ref;
+      PsiExpression qualifier = call.getMethodExpression().getQualifierExpression();
+      if (PsiUtil.isConstantExpression(qualifier) &&
+          Stream.of(call.getArgumentList().getExpressions()).allMatch(PsiUtil::isConstantExpression)) {
+        return false;
+      }
+    }
+    else {
+      return false;
+    }
     PsiElement parent = PsiUtil.skipParenthesizedExprUp(ref.getParent());
     PsiBinaryExpression binOp = tryCast(parent, PsiBinaryExpression.class);
     if (binOp != null && ComparisonUtils.isEqualityComparison(binOp) &&
         (ExpressionUtils.isZero(binOp.getLOperand()) || ExpressionUtils.isZero(binOp.getROperand()))) {
       return false;
     }
-    PsiMethod method = PsiTreeUtil.getParentOfType(parent, PsiMethod.class, true, PsiLambdaExpression.class, PsiClass.class);
-    if (MethodUtils.isHashCode(method)) {
-      // Standard hashCode template generates int result = 0; result = result * 31 + ...;
-      // so annoying warnings might be produced there
-      if (ref instanceof PsiPolyadicExpression && ((PsiPolyadicExpression)ref).getOperationTokenType().equals(JavaTokenType.ASTERISK)) {
-        return false;
-      }
-    }
     return true;
   }
 

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

@@ -229,16 +229,4 @@ public class LongRangeBasics {
       System.out.println();
     }
   }
-  
-  class HashCode {
-    Object a, b, c;
-    
-    public int hashCode() {
-      int result = 0;
-      result = result * 31 + a.hashCode();
-      result = result * 31 + b.hashCode();
-      result = result * 31 + c.hashCode();
-      return result;
-    }
-  }
 }

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

@@ -0,0 +1,29 @@
+class HashCode {
+  Object a, b, c;
+
+  public int hashCode() {
+    int result = 0;
+    result = result * 31 + a.hashCode();
+    result = result * 31 + b.hashCode();
+    result = result * 31 + c.hashCode();
+    return result;
+  }
+
+  public int hashCode2() {
+    int result = 0;
+    result = <warning descr="Result of 'result * 31' is always '0'">result * 31</warning> + a.hashCode();
+    result = result * 31 + b.hashCode();
+    result = result * 31 + c.hashCode();
+    return result;
+  }
+
+  static final String STRING = "123456";
+  static final String PREFIX = "123";
+  
+  void testIndexOf(String s) {
+    int pos = STRING.indexOf(PREFIX);
+    if (s.equals(PREFIX)) {
+      int pos2 = <warning descr="Result of 's.indexOf(PREFIX)' is always '0'">s.indexOf(PREFIX)</warning>;
+    }
+  }
+}

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

@@ -70,4 +70,5 @@ public class DataFlowRangeAnalysisTest extends DataFlowInspectionTestCase {
   public void testWidenPlusInLoop() { doTest(); }
   public void testWidenMulInLoop() { doTest(); }
   public void testReduceBinOpOnCast() { doTest(); }
+  public void testSuppressZeroReport() { doTest(); }
 }