[MINOR] Remove inappropriate type notation and extra anonymous closure within functional transformations

## What changes were proposed in this pull request?

This PR removes

- Inappropriate type notations
    For example, from
    ```scala
    words.foreachRDD { (rdd: RDD[String], time: Time) =>
    ...
    ```
    to
    ```scala
    words.foreachRDD { (rdd, time) =>
    ...
    ```

- Extra anonymous closure within functional transformations.
    For example,
    ```scala
    .map(item => {
      ...
    })
    ```

    which can be just simply as below:

    ```scala
    .map { item =>
      ...
    }
    ```

and corrects some obvious style nits.

## How was this patch tested?

This was tested after adding rules in `scalastyle-config.xml`, which ended up with not finding all perfectly.

The rules applied were below:

- For the first correction,

```xml
<check customId="NoExtraClosure" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
    <parameters><parameter name="regex">(?m)\.[a-zA-Z_][a-zA-Z0-9]*\(\s*[^,]+s*=>\s*\{[^\}]+\}\s*\)</parameter></parameters>
</check>
```

```xml
<check customId="NoExtraClosure" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
    <parameters><parameter name="regex">\.[a-zA-Z_][a-zA-Z0-9]*\s*[\{|\(]([^\n>,]+=>)?\s*\{([^()]|(?R))*\}^[,]</parameter></parameters>
</check>
```

- For the second correction
```xml
<check customId="TypeNotation" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
    <parameters><parameter name="regex">\.[a-zA-Z_][a-zA-Z0-9]*\s*[\{|\(]\s*\([^):]*:R))*\}^[,]</parameter></parameters>
</check>
```

**Those rules were not added**

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #12413 from HyukjinKwon/SPARK-style.

6 files changed, 13 insertions, 21 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
index 37ff6ab6f6..6591559426 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
@@ -172,8 +172,8 @@ class Analyzer(
     private def assignAliases(exprs: Seq[NamedExpression]) = {
       exprs.zipWithIndex.map {
         case (expr, i) =>
-          expr transformUp {
-            case u @ UnresolvedAlias(child, optionalAliasName) => child match {
+          expr.transformUp { case u @ UnresolvedAlias(child, optionalAliasName) =>
+            child match {
               case ne: NamedExpression => ne
               case e if !e.resolved => u
               case g: Generator => MultiAlias(g, Nil)
@@ -215,7 +215,7 @@ class Analyzer(
      *  represented as the bit masks.
      */
     def bitmasks(r: Rollup): Seq[Int] = {
-      Seq.tabulate(r.groupByExprs.length + 1)(idx => {(1 << idx) - 1})
+      Seq.tabulate(r.groupByExprs.length + 1)(idx => (1 << idx) - 1)
     }
 
     /*
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Projection.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Projection.scala
index 354311c5e7..27ad8e4cf2 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Projection.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Projection.scala
@@ -168,9 +168,7 @@ object FromUnsafeProjection {
    * Returns an UnsafeProjection for given Array of DataTypes.
    */
   def apply(fields: Seq[DataType]): Projection = {
-    create(fields.zipWithIndex.map(x => {
-      new BoundReference(x._2, x._1, true)
-    }))
+    create(fields.zipWithIndex.map(x => new BoundReference(x._2, x._1, true)))
   }
 
   /**
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 6c8f8f40dd..c46bdfb2b5 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
@@ -314,11 +314,9 @@ object SetOperationPushDown extends Rule[LogicalPlan] with PredicateHelper {
       assert(children.nonEmpty)
       val (deterministic, nondeterministic) = partitionByDeterministic(condition)
       val newFirstChild = Filter(deterministic, children.head)
-      val newOtherChildren = children.tail.map {
-        child => {
-          val rewrites = buildRewrites(children.head, child)
-          Filter(pushToRight(deterministic, rewrites), child)
-        }
+      val newOtherChildren = children.tail.map { child =>
+        val rewrites = buildRewrites(children.head, child)
+        Filter(pushToRight(deterministic, rewrites), child)
       }
       Filter(nondeterministic, Union(newFirstChild +: newOtherChildren))
 
@@ -360,7 +358,7 @@ object ColumnPruning extends Rule[LogicalPlan] {
     case a @ Project(_, e @ Expand(_, _, grandChild)) if (e.outputSet -- a.references).nonEmpty =>
       val newOutput = e.output.filter(a.references.contains(_))
       val newProjects = e.projections.map { proj =>
-        proj.zip(e.output).filter { case (e, a) =>
+        proj.zip(e.output).filter { case (_, a) =>
           newOutput.contains(a)
         }.unzip._1
       }
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala
index 0c3e3c3fc1..f021f3758c 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala
@@ -60,9 +60,7 @@ case class ShuffledHashJoin(
     val context = TaskContext.get()
     val relation = HashedRelation(iter, buildKeys, taskMemoryManager = context.taskMemoryManager())
     // This relation is usually used until the end of task.
-    context.addTaskCompletionListener((t: TaskContext) =>
-      relation.close()
-    )
+    context.addTaskCompletionListener(_ => relation.close())
     relation
   }
 
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala
index d603f63a08..9afbd0e994 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala
@@ -431,7 +431,7 @@ private[sql] object StatFunctions extends Logging {
       s"exceed 1e4. Currently $columnSize")
     val table = counts.groupBy(_.get(0)).map { case (col1Item, rows) =>
       val countsRow = new GenericMutableRow(columnSize + 1)
-      rows.foreach { (row: Row) =>
+      rows.foreach { row =>
         // row.get(0) is column 1
         // row.get(1) is column 2
         // row.get(2) is the frequency
diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveUDFs.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveUDFs.scala
index 784b018353..5aab4132bc 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveUDFs.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveUDFs.scala
@@ -82,7 +82,7 @@ private[hive] case class HiveSimpleUDF(
 
   // TODO: Finish input output types.
   override def eval(input: InternalRow): Any = {
-    val inputs = wrap(children.map(c => c.eval(input)), arguments, cached, inputDataTypes)
+    val inputs = wrap(children.map(_.eval(input)), arguments, cached, inputDataTypes)
     val ret = FunctionRegistry.invoke(
       method,
       function,
@@ -152,10 +152,8 @@ private[hive] case class HiveGenericUDF(
     var i = 0
     while (i < children.length) {
       val idx = i
-      deferredObjects(i).asInstanceOf[DeferredObjectAdapter].set(
-        () => {
-          children(idx).eval(input)
-        })
+      deferredObjects(i).asInstanceOf[DeferredObjectAdapter]
+        .set(() => children(idx).eval(input))
       i += 1
     }
     unwrap(function.evaluate(deferredObjects), returnInspector)