Missing ParameterizedType for Option in LTS 3.3

[jchyb]

Compiler version

3.3.0, 3.3.1, 3.3.3 (works correctly in 3.4.0 and 3.4.1)

Minimized code

class ClassWithOption {
  val a: Option[Int] = None
}

object Test {
  def main(args: Array[String]) =
    classOf[ClassWithOption].getDeclaredFields.foreach { field =>
      println(field.toString + " parametrised " + field.getGenericType.isInstanceOf[java.lang.reflect.ParameterizedType])
    }
}

Output

In LTS:

private final scala.Option ClassWithOption.a parametrised false

In 3.4.0 and 3.4.1:

private final scala.Option ClassWithOption.a parametrised true

When using the CFR decompiler on ClassWIthOption I get:
In LTS:

/*
 * Decompiled with CFR 0.152.
 * 
 * Could not load the following classes:
 *  scala.None$
 *  scala.Option
 */
import scala.None$;
import scala.Option;

public class ClassWithOption {
    private final Option a = None$.MODULE$;

    public Option<Object> a() {
        return this.a;
    }
}

In 3.4:

/*
 * Decompiled with CFR 0.152.
 * 
 * Could not load the following classes:
 *  scala.None$
 *  scala.Option
 */
import scala.None$;
import scala.Option;

public class ClassWithOption {
    private final Option<Object> a = None$.MODULE$;

    public Option<Object> a() {
        return this.a;
    }
}

Expectation

I expect the behavior in 3.4.
Some libraries may use java reflection features which depend on the erased type parameter being there. I suspect overeager type parameter erasure was not intentional, which is why it came back in 3.4.