[java-dfa] Ignore some contracts if method return value is not used

GitOrigin-RevId: 2834d00f1385759947351f8b93d8fc6a18a45106

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

@@ -1710,6 +1710,11 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
       anchor = reference;
     }
     else {
+      if (ExpressionUtils.isVoidContext(expression) && ContainerUtil.all(contracts, c -> 
+        c.getReturnValue() != ContractReturnValue.fail() && !(c.getReturnValue() instanceof ContractReturnValue.ParameterReturnValue))) {
+        // Do not track contracts if return value is not used
+        contracts = Collections.emptyList();
+      }
       addInstruction(new MethodCallInstruction(expression, myFactory.createValue(expression), contracts));
       anchor = expression;
     }

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

@@ -0,0 +1,26 @@
+import org.jetbrains.annotations.*;
+
+class Inspection {
+
+  @Nullable
+  private Object o;
+
+  public void test1() {
+    check(o);
+    foo(<warning descr="Argument 'o' might be null">o</warning>);
+  }
+
+  public static Object check(@Nullable final Object o) {
+    if (o != null && is()) {
+    }
+    return <warning descr="'null' is returned by the method which is not declared as @Nullable">null</warning>;
+  }
+
+  private static boolean is() {
+    System.out.println();
+    return true;
+  }
+
+  private static void foo(@NotNull final Object obj) {
+  }
+}

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

@@ -693,4 +693,5 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testFinalStaticFields() { doTest(); }
   public void testReassignInConstructor() { doTest(); }
   public void testCollectionViewsSize() { doTest(); }
+  public void testFlushedNullableOnUnknownCall() { doTest(); }
 }