paramClasses is empty in inline applyDynamic

[andrzejressel]

Compiler version

3.3.0

Minimized code

https://scastie.scala-lang.org/wUWQ0uNJRkqyLAz19jO8xw

class MyRecord extends Selectable:
  def applyDynamic(name: String, paramClasses: Class[_]*)(args: Any*): Any = {
    println(name)
    println(paramClasses)
    println(args)
    ()
  }

class MyRecordTransparent extends Selectable:
  inline transparent def applyDynamic(name: String, paramClasses: Class[_]*)(args: Any*): Any = {
    println(name)
    println(paramClasses)
    println(args)
    ()
  }

type Person = MyRecord {
  def test(a: String, b: Int): Unit
}


type PersonTransparent = MyRecordTransparent {
  def test(a: String, b: Int): Unit
}

val person = MyRecord().asInstanceOf[Person]
val personTransparent = MyRecordTransparent().asInstanceOf[PersonTransparent]

println("Normal")
person.test("test", 42)
println("Transparent")
personTransparent.test("test", 42)

Output

Normal
test
ArraySeq(class java.lang.String, int)
ArraySeq(test, 42)
Transparent
test
ArraySeq()
ArraySeq(test, 42)

Expectation

Normal
test
ArraySeq(class java.lang.String, int)
ArraySeq(test, 42)
Transparent
test
ArraySeq(class java.lang.String, int)
ArraySeq(test, 42)

[nicolasstucki]

The issue is that we first type the tree and then add the Class parameters. In the case of inlining, the call does not exist anymore. See addClassOfs(typed(scall)) bellow.

https://github.com/lampepfl/dotty/blob/94f5cdb880bf04d4c2dcd106efad5629db31b137/compiler/src/dotty/tools/dotc/typer/Dynamic.scala#L198-L213