[SPARK-7562][SPARK-6444][SQL] Improve error reporting for expression data type mismatch

It seems hard to find a common pattern of checking types in `Expression`. Sometimes we know what input types we need(like `And`, we know we need two booleans), sometimes we just have some rules(like `Add`, we need 2 numeric types which are equal). So I defined a general interface `checkInputDataTypes` in `Expression` which returns a `TypeCheckResult`. `TypeCheckResult` can tell whether this expression passes the type checking or what the type mismatch is.

This PR mainly works on apply input types checking for arithmetic and predicate expressions.

TODO: apply type checking interface to more expressions.

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #6405 from cloud-fan/6444 and squashes the following commits:

b5ff31b [Wenchen Fan] address comments
b917275 [Wenchen Fan] rebase
39929d9 [Wenchen Fan] add todo
0808fd2 [Wenchen Fan] make constrcutor of TypeCheckResult private
3bee157 [Wenchen Fan] and decimal type coercion rule for binary comparison
8883025 [Wenchen Fan] apply type check interface to CaseWhen
cffb67c [Wenchen Fan] to have resolved call the data type check function
6eaadff [Wenchen Fan] add equal type constraint to EqualTo
3affbd8 [Wenchen Fan] more fixes
654d46a [Wenchen Fan] improve tests
e0a3628 [Wenchen Fan] improve error message
1524ff6 [Wenchen Fan] fix style
69ca3fe [Wenchen Fan] add error message and tests
c71d02c [Wenchen Fan] fix hive tests
6491721 [Wenchen Fan] use value class TypeCheckResult
7ae76b9 [Wenchen Fan] address comments
cb77e4f [Wenchen Fan] Improve error reporting for expression data type mismatch

1 files changed, 2 insertions, 2 deletions

diff --git a/core/src/test/scala/org/apache/spark/SparkFunSuite.scala b/core/src/test/scala/org/apache/spark/SparkFunSuite.scala
index 8cb3443326..9be9db01c7 100644
--- a/core/src/test/scala/org/apache/spark/SparkFunSuite.scala
+++ b/core/src/test/scala/org/apache/spark/SparkFunSuite.scala
@@ -30,8 +30,8 @@ private[spark] abstract class SparkFunSuite extends FunSuite with Logging {
    * Log the suite name and the test name before and after each test.
    *
    * Subclasses should never override this method. If they wish to run
-   * custom code before and after each test, they should should mix in
-   * the {{org.scalatest.BeforeAndAfter}} trait instead.
+   * custom code before and after each test, they should mix in the
+   * {{org.scalatest.BeforeAndAfter}} trait instead.
    */
   final protected override def withFixture(test: NoArgTest): Outcome = {
     val testName = test.text