Error when using tuple type with selectDynamic method syntax

[albertpchen]

Minimized code

import scala.language.dynamics
object Dyn extends Dynamic:
  def selectDynamic[T](name: String): Option[T] = None

val a: Option[(Int, Int)] = Dyn.asdf[Tuple2[Int, Int]] // works fine
val b: Option[(Int, Int)] = Dyn.selectDynamic[(Int, Int)]("asdf") // works fine
val c: Option[(Int, Int)] = Dyn.asdf[(Int, Int)] // fails

Output

scala> import scala.language.dynamics

scala> object Dyn extends Dynamic:
     |   def selectDynamic[T](name: String): Option[T] = None
     |
// defined object Dyn

scala> val a: Option[(Int, Int)] = Dyn.asdf[Tuple2[Int, Int]] // works fine
val a: Option[(Int, Int)] = None

scala> val b: Option[(Int, Int)] = Dyn.selectDynamic[(Int, Int)]("asdf") // works fine
val b: Option[(Int, Int)] = None

scala> val c: Option[(Int, Int)] = Dyn.asdf[(Int, Int)] // fails
1 |val c: Option[(Int, Int)] = Dyn.asdf[(Int, Int)] // fails
  |                                      ^
  |cannot infer type; expected type class dotty.tools.dotc.typer.ProtoTypes$AnyTypeConstructorProto$ is not fully defined

Expectation

the last line val a: Option[(Int, Int)] = Dyn.asdf[(Int, Int)] should return None rather than report an error. Running this in a scala 2.13.4 repl outputs the expected results.