unused return value: report native methods (IDEA-90127)

java/java-impl/src/com/intellij/codeInspection/reference/RefMethodImpl.java

@@ -356,7 +356,7 @@ public class RefMethodImpl extends RefJavaElementImpl implements RefMethod {
   }
 
   public boolean hasSuperMethods() {
-    return !getSuperMethods().isEmpty() || isLibraryOverride(new HashSet<RefMethod>());
+    return !getSuperMethods().isEmpty() || isExternalOverride();
   }
 
   public boolean isReferenced() {

java/java-impl/src/com/intellij/codeInspection/unusedReturnValue/UnusedReturnValue.java

@@ -30,6 +30,7 @@ import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.refactoring.changeSignature.ChangeSignatureProcessor;
 import com.intellij.refactoring.changeSignature.ParameterInfoImpl;
 import com.intellij.util.IncorrectOperationException;
+import com.intellij.util.containers.HashSet;
 import org.jdom.Element;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -56,16 +57,19 @@ public class UnusedReturnValue extends GlobalJavaInspectionTool{
       final RefMethod refMethod = (RefMethod)refEntity;
 
       if (refMethod.isConstructor()) return null;
-      if (refMethod.hasSuperMethods()) return null;
+      if (!refMethod.getSuperMethods().isEmpty()) return null;  
       if (refMethod.getInReferences().size() == 0) return null;
 
       if (!refMethod.isReturnValueUsed()) {
         final PsiMethod psiMethod = (PsiMethod)refMethod.getElement();
         if (IGNORE_BUILDER_PATTERN && PropertyUtil.isSimplePropertySetter(psiMethod)) return null;
+
+        final boolean isNative = psiMethod.hasModifierProperty(PsiModifier.NATIVE);
+        if (refMethod.isExternalOverride() && !isNative) return null;
         return new ProblemDescriptor[]{manager.createProblemDescriptor(psiMethod.getNavigationElement(),
                                                                        InspectionsBundle
                                                                          .message("inspection.unused.return.value.problem.descriptor"),
-                                                                       getFix(processor), ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                                                       !isNative ? getFix(processor) : null, ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
                                                                        false)};
       }
     }

java/java-tests/testData/inspection/unusedReturnValue/native/expected.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+  <problem>
+    <file>Test.java</file>
+    <line>2</line>
+    <description>Return value of the method is never used</description>
+  </problem>
+</problems>

java/java-tests/testData/inspection/unusedReturnValue/native/src/Test.java

@@ -0,0 +1,7 @@
+class Test {
+  private static native boolean isUnused();
+
+  public static void main(String[] args) {
+    Test.isUnused();
+  }
+}

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

@@ -31,6 +31,10 @@ public class UnusedReturnValueTest extends InspectionTestCase {
     doTest();
   }
 
+  public void testNative() throws Exception {
+    doTest();
+  }
+
   public void testHierarchy() throws Exception {
     doTest();
   }