Addresses PR comments

Author: liancheng

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala

@@ -562,6 +562,9 @@ class Analyzer(
 
       resolveExpression(unbound, LocalRelation(attributes), throws = true) transform {
         case n: NewInstance
+          // If this is an inner class of another class, register the outer object in `OuterScopes`.
+          // Note that static inner classes (e.g., inner classes within Scala objects) don't need
+          // outer pointer registration.
           if n.outerPointer.isEmpty &&
              n.cls.isMemberClass &&
              !Modifier.isStatic(n.cls.getModifiers) =>

sql/core/src/test/scala/org/apache/spark/sql/DatasetSuite.scala

@@ -622,8 +622,7 @@ class DatasetSuite extends QueryTest with SharedSQLContext {
       Some(1), Some(2), Some(3))
   }
 
-  test("SPARK-13540 add Scala object to OuterScopes") {
-    OuterScopes.addOuterScope(OuterObject)
+  test("SPARK-13540 Dataset of nested class defined in Scala object") {
     checkAnswer(
       Seq(OuterObject.InnerClass("foo")).toDS(),
       OuterObject.InnerClass("foo"))