constructor param names are not accessible from Java reflection Contructor Params for case classes

[pjfanning]

Compiler version

3.0.0-RC1

Minimized code

case class TestCaseClass(oof: String, bar: String)

val cls = classOf[TestCaseClass]

val constructor = cls.getConstructors.head

val param1 = constructor.getParameters.head

println(s"constructor params ${constructor.getParameters.map(_.getName).toSeq}")

Output

constructor params ArraySeq(arg0, arg1)

Java class ConstructorParameters default to using the form arg0 when the underlying name is null.

Expectation

Same code in Scala 2.13.4 produces

constructor params ArraySeq(oof, bar)

Jackson-Module-Scala currently depends on java reflection for most of its functionality and the missing names in the constructor params affect a number of use cases.

[SethTisue]

the PR with Scala 2's support for this was scala/scala#4735 (2016)