Compiler crashes when deriving TypeInformation for case class with @DataTypeHint

[megri]

Scala version: 3.1.3

The compiler crashes with Error: Unexpected error when compiling project_ea109e5296_ea109e5296-b3409dd64e: 'class Class' when trying to derive an instance of TypeInformation[?] for a case class that uses org.apache.flink.table.annotation.DataTypeHint

I minimized the issue to the following, runnable with scala-cli

//> using scala "3.1.3"
//> using lib "org.apache.flink:flink-table-runtime:1.15.2"
//> using lib "io.findify::flink-adt:0.6.1"

package com.stuff

import io.findify.flinkadt.api.*
import org.apache.flink.table.annotation.DataTypeHint
import org.apache.flink.api.common.typeinfo.TypeInformation


case class Test(@DataTypeHint("BIGINT") timestamp: Long)

@main def run() =
  summon[TypeInformation[Test]]

[megri]

It's possible this is a Dotty compiler issue but I'm not sure 🤔

[NickBurkard]

I tried replicating this locally, it only fails on Scala 3, 2.12 & 2.13 work. I think this may be a Scala 3 compiler bug. 😅

package io.findify.flinkadt

import io.findify.flinkadt.api._
import org.apache.flink.table.annotation.DataTypeHint
import org.scalatest.flatspec.AnyFlatSpec
import org.scalatest.matchers.should.Matchers

class DataTypeHintTest extends AnyFlatSpec with Matchers {
  it should "support deriving type information with data type hints" in {
    drop(deriveTypeInformation[UsesDataTypeHint])
  }
}

case class UsesDataTypeHint(@DataTypeHint("BIGINT") foo: Long)

Scala 3 error:

Error while emitting DataTypeHintTest.scala
...
[error] java.util.NoSuchElementException: class Class
[error] scala.collection.mutable.AnyRefMap$ExceptionDefault.apply(AnyRefMap.scala:508)
[error] scala.collection.mutable.AnyRefMap$ExceptionDefault.apply(AnyRefMap.scala:507)

[megri]

I tried replicating this locally, it only fails on Scala 3, 2.12 & 2.13 work. I think this may be a Scala 3 compiler bug. 😅

Thanks for confirming. I tried replicating the issue by reimplementing the DataTypeHint interface but couldn't get it to trigger when I did so. I'll re-report the issue in the dotty-repo and see if they can help me out.