prefer interface as super method when class extends unrelated class and interface (IDEA-99347)

java/java-psi-impl/src/com/intellij/psi/impl/PsiSuperMethodImplUtil.java

@@ -277,8 +277,8 @@ public class PsiSuperMethodImplUtil {
               }
 
               if (containingClass != null) {
-                if (!containingClass.isInterface()) {
-                  return true;
+                if (containingClass.isInterface()) {
+                  return false;
                 }
 
                 if (!aClass.isInterface() && !InheritanceUtil.isInheritorOrSelf(superClass, containingClass, true)) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting/IDEA99347.java

@@ -0,0 +1,12 @@
+interface Errors {
+  java.util.Collection<java.lang.String> getErrorMessages();
+
+}
+
+class Test extends AbstrClass implements Errors {
+}
+
+
+abstract class AbstrClass {
+  public java.util.Collection getErrorMessages() {return null;}
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/GenericsHighlightingTest.java

@@ -202,6 +202,7 @@ public class GenericsHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testIDEA57539() { doTest5(false); }
   public void testIDEA67570() { doTest5(false); }
   public void testIDEA99061() { doTest5(false); }
+  public void testIDEA99347() { doTest5(false); }
 
   public void testJavaUtilCollections_NoVerify() throws Exception {
     PsiClass collectionsClass = getJavaFacade().findClass("java.util.Collections", GlobalSearchScope.moduleWithLibrariesScope(getModule()));