Unevaluable expr is set to FIRST/LAST ignoreNullsExpr in distinct aggregates

scala> sql("SELECT FIRST(DISTINCT v) FROM VALUES 1, 2, 3 t(v)").show()
...
Caused by: java.lang.UnsupportedOperationException: Cannot evaluate expression: false#37
  at org.apache.spark.sql.catalyst.expressions.Unevaluable$class.eval(Expression.scala:258)
  at org.apache.spark.sql.catalyst.expressions.AttributeReference.eval(namedExpressions.scala:226)
  at org.apache.spark.sql.catalyst.expressions.aggregate.First.ignoreNulls(First.scala:68)
  at org.apache.spark.sql.catalyst.expressions.aggregate.First.updateExpressions$lzycompute(First.scala:82)
  at org.apache.spark.sql.catalyst.expressions.aggregate.First.updateExpressions(First.scala:81)
  at org.apache.spark.sql.execution.aggregate.HashAggregateExec$$anonfun$15.apply(HashAggregateExec.scala:268)