Extract base interface for Kotlin light elements

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/jetAsJava/KotlinLightElement.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.jet.lang.resolve.java.jetAsJava
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.jet.lang.psi.JetDeclaration
+
+trait KotlinLightElement<T: JetDeclaration, D: PsiElement> {
+    val origin: T?
+    val delegate: D
+}

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/jetAsJava/KotlinLightMethod.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2013 JetBrains s.r.o.
+ * Copyright 2010-2014 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,7 +20,4 @@ import com.intellij.psi.PsiMethod;
 import org.jetbrains.jet.lang.psi.JetDeclaration;
 
 /** Java method created for Kotlin declaration to make it resolvable in Java */
-public interface KotlinLightMethod extends PsiMethod {
-    JetDeclaration getOrigin();
-    PsiMethod getDelegate();
-}
+public trait KotlinLightMethod: PsiMethod, KotlinLightElement<JetDeclaration, PsiMethod>