Remove semanticEquals Expression

Author: wangyum

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/QueryPlanConstraints.scala

@@ -143,7 +143,10 @@ trait ConstraintHelper {
         inferredConstraints ++= inferInequalityConstraints(lessThans - lt, r, l, lt)
       case _ => // No inference
     }
-    inferredConstraints -- constraints -- greaterThans -- lessThans
+    (inferredConstraints -- constraints -- greaterThans -- lessThans).foldLeft(Set[Expression]()) {
+      case (acc, e) if acc.exists(_.semanticEquals(e)) => acc.dropWhile(_.semanticEquals(e))
+      case (acc, e) => acc + e
+    }
   }
 
   private def replaceConstraints(

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/InferFiltersFromConstraintsSuite.scala

@@ -402,7 +402,7 @@ class InferFiltersFromConstraintsSuite extends PlanTest {
   test("Constraints inferred from inequality attributes: case2") {
     val original = testRelation.where('a < 'b && 'b < 'c && 'c < 5)
     val optimized = testRelation.where(IsNotNull('a) && IsNotNull('b) && IsNotNull('c)
-      && 'a < 'b && 'b < 'c && 'a < 5 && 'b < 5 && 'c < 5 && 'c > 'a)
+      && 'a < 'b && 'b < 'c && 'a < 5 && 'b < 5 && 'c < 5)
     comparePlans(Optimize.execute(original.analyze), optimized.analyze)
   }