[SPARK-4959][SQL] Attributes are case sensitive when using a select query from a projection(Backport to Spark-1.2)

This is a follow up of #3796 , which can not be merged back to Spark-1.2. Manually merge it.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #4013 from chenghao-intel/spark_4959_backport and squashes the following commits:

1f6c93d [Cheng Hao] backport to Spark-1.2

1 files changed, 4 insertions, 4 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
index f164a6c68a..c2aafb9fb8 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
@@ -142,16 +142,16 @@ object ColumnPruning extends Rule[LogicalPlan] {
     case Project(projectList1, Project(projectList2, child)) =>
       // Create a map of Aliases to their values from the child projection.
       // e.g., 'SELECT ... FROM (SELECT a + b AS c, d ...)' produces Map(c -> Alias(a + b, c)).
-      val aliasMap = projectList2.collect {
-        case a @ Alias(e, _) => (a.toAttribute: Expression, a)
-      }.toMap
+      val aliasMap = AttributeMap(projectList2.collect {
+        case a @ Alias(e, _) => (a.toAttribute, a)
+      })
 
       // Substitute any attributes that are produced by the child projection, so that we safely
       // eliminate it.
       // e.g., 'SELECT c + 1 FROM (SELECT a + b AS C ...' produces 'SELECT a + b + 1 ...'
       // TODO: Fix TransformBase to avoid the cast below.
       val substitutedProjection = projectList1.map(_.transform {
-        case a if aliasMap.contains(a) => aliasMap(a)
+        case a: Attribute if aliasMap.contains(a) => aliasMap(a)
       }).asInstanceOf[Seq[NamedExpression]]
 
       Project(substitutedProjection, child)