Implementation Navigation: Add tests for enum entries

#KT-3540 Fixed

idea/testData/navigation/implementations/EnumEntriesInheritance.kt

@@ -0,0 +1,16 @@
+enum class <caret>E {
+    open fun foo(n: Int): Int = n
+
+    O
+    A {
+        override fun foo(n: Int): Int = n + 1
+
+    }
+    B {
+        override fun foo(n: Int): Int = n + 2
+
+    }
+}
+
+// REF: (E).A
+// REF: (E).B

idea/testData/navigation/implementations/OverridesInEnumEntries.kt

@@ -0,0 +1,16 @@
+enum class E {
+    open fun <caret>foo(n: Int): Int = n
+
+    O
+    A {
+        override fun foo(n: Int): Int = n + 1
+
+    }
+    B {
+        override fun foo(n: Int): Int = n + 2
+
+    }
+}
+
+// REF: (in E.A).foo(Int)
+// REF: (in E.B).foo(Int)

idea/tests/org/jetbrains/jet/plugin/navigation/JetGotoImplementationTest.java

@@ -53,6 +53,14 @@ public class JetGotoImplementationTest extends LightCodeInsightTestCase {
         doTest();
     }
 
+    public void testOverridesInEnumEntries() {
+        doTest();
+    }
+
+    public void testEnumEntriesInheritance() {
+        doTest();
+    }
+
     @NotNull
     @Override
     protected String getTestDataPath() {