IG: warn on covariant equals() in interface but not implementations

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/bugs/CovariantEqualsInspection.java

@@ -68,7 +68,7 @@ public class CovariantEqualsInspection extends BaseInspection {
         return;
       }
       final PsiClass aClass = method.getContainingClass();
-      if (aClass == null || aClass.isInterface()) {
+      if (aClass == null) {
         return;
       }
       final PsiMethod[] methods = aClass.getMethods();

plugins/InspectionGadgets/test/com/siyeh/igtest/bugs/covariant_equals/CovariantEquals.java

@@ -1,5 +1,5 @@
 interface I {
-  boolean equals(I i);
+  boolean <warning descr="'equals()' should take 'Object' as its argument">equals</warning>(I i);
 }
 class A {