3.2.1 regression with partially applied classes

[andrzejressel]

Compiler version

3.2.1
3.2.2-RC1

Minimized code

//> using platform "jvm"
//> using scala "3.2.1"

@main
def main() = {
  A { (a: Unit) => () }
}

object A {
  def apply[E] = new PartiallyApplied[E]
  final class PartiallyApplied[E] {
    def apply[T1](fn: (T1) => Unit): Unit = ()
  }
}

Output

[error] .\partial.scala:6:3: method apply in object A does not take parameters
[error]   A { (a: Unit) => () }
[error]

Expectation

No error like with Scala 3.2.0

[KacperFKorban]

Minimized a bit:

final class PartiallyApplied {
  def apply(fn: Int): Unit = ()
}

object A {
  def apply[X] = new PartiallyApplied
}

def Test =
  A(1)

[andrzejressel]

I've bisected it to 882b435

[odersky]

Yes, that's intentioinal. We do not synthesize more than one apply method in a row. But here A(1) would expand to

A.apply[Int].apply(1)

This restriction is to guard against infinite apply expansion.