Partition discovery fails with explicitly written long partitions

We have parquet data written from Spark1.6 that, when read from 2.0.1, produces errors.

case class A(a: Long, b: Int)
val as = Seq(A(1,2))
//partition explicitly written
spark.createDataFrame(as).write.parquet("/data/a=1/")
spark.read.parquet("/data/").collect

The above code fails; stack trace attached.

If an integer used, explicit partition discovery succeeds.

case class A(a: Int, b: Int)
val as = Seq(A(1,2))
//partition explicitly written
spark.createDataFrame(as).write.parquet("/data/a=1/")
spark.read.parquet("/data/").collect

The action succeeds. Additionally, if 'partitionBy' is used instead of explicit writes, partition discovery succeeds.

Question: Is the first example a reasonable use case? PartitioningUtils seems to default to Integer types unless the partition value exceeds the integer type's length.