change signature: highest visibility should not return PUBLIC all at once (IDEA-111739)

java/java-psi-api/src/com/intellij/util/VisibilityUtil.java

@@ -50,13 +50,7 @@ public class VisibilityUtil  {
 
   @PsiModifier.ModifierConstant
   public static String getHighestVisibility(@PsiModifier.ModifierConstant String v1, @PsiModifier.ModifierConstant String v2) {
-    if(v1.equals(v2)) return v1;
-
-    if(PsiModifier.PRIVATE.equals(v1)) return v2;
-    if(PsiModifier.PUBLIC.equals(v1)) return PsiModifier.PUBLIC;
-    if(PsiModifier.PRIVATE.equals(v2)) return v1;
-
-    return PsiModifier.PUBLIC;
+    return compare(v1, v2) < 0 ? v1 : v2;
   }
 
   public static void escalateVisibility(PsiMember modifierListOwner, PsiElement place) throws IncorrectOperationException {

java/java-tests/testData/refactoring/changeSignature/VisibilityOfOverriddenMethod.java

@@ -0,0 +1,10 @@
+class Test {
+    protected void fo<caret>o() {
+    }
+}
+
+class subclass extends Test {
+    @Override
+    protected void foo() {
+    }
+}

java/java-tests/testData/refactoring/changeSignature/VisibilityOfOverriddenMethod_after.java

@@ -0,0 +1,10 @@
+class Test {
+    void foo() {
+    }
+}
+
+class subclass extends Test {
+    @Override
+    protected void foo() {
+    }
+}

java/java-tests/testSrc/com/intellij/refactoring/ChangeSignatureTest.java

@@ -355,6 +355,10 @@ public class ChangeSignatureTest extends LightRefactoringTestCase {
     doTest(null, null, "Exception", new SimpleParameterGen(), new SimpleExceptionsGen(), false);
   }
 
+  public void testVisibilityOfOverriddenMethod() throws Exception {
+    doTest(PsiModifier.PACKAGE_LOCAL, "foo", "void", new ParameterInfoImpl[0], new ThrownExceptionInfo[0], false);
+  }
+
   public void testRemoveExceptions() throws Exception {
     doTest(null, null, "void", new SimpleParameterGen(), new SimpleExceptionsGen(), false);
   }