Refactored reference shortening utility (added expression references shortening and rewritten to Kotlin)

compiler/frontend/src/org/jetbrains/jet/lang/psi/JetTypeArgumentList.java

@@ -37,6 +37,7 @@ public class JetTypeArgumentList extends JetElementImpl {
         return visitor.visitTypeArgumentList(this, data);
     }
 
+    @NotNull
     public List<JetTypeProjection> getArguments() {
         return findChildrenByType(JetNodeTypes.TYPE_PROJECTION);
     }

compiler/jet.as.java.psi/src/org/jetbrains/jet/asJava/KotlinLightMethodForDeclaration.kt

@@ -82,7 +82,7 @@ public class KotlinLightMethodForDeclaration(manager: PsiManager, val method: Ps
 
     override fun getParameterList(): PsiParameterList = paramsList.getValue()!!
 
-    override fun copy(): PsiElement? {
+    override fun copy(): PsiElement {
         return KotlinLightMethodForDeclaration(getManager()!!, method, jetDeclaration.copy() as JetDeclaration, getContainingClass()!!)
     }
 }