Exception when printing skolem type in singleton instance.

[rssh]

Minimized code

file X.scala:

package x

import scala.quoted._


object X {

  inline def printType[A](inline x: A): String = ${
    printTypeImpl[A]('x)
  }

  def printTypeImpl[A:Type](x:Expr[A])(using Quotes): Expr[String] = {
    import quotes.reflect._
    val value: String = x.asTerm.tpe.show
    println(value)
    Expr( value )
  }

}

file Main.scala:

package x

import scala.concurrent._
import scala.concurrent.duration._
import scala.language.postfixOps

object Main:

 def main(args:Array[String]):Unit =
   val latch = Vector.fill(10)(Future successful 10)
   X.printType( { Await.ready(latch(3) , 1 second) } )

Output (click arrow to expand)

[info] Compiling 1 Scala source to /Users/rssh/tests/dotty/assert-in-print/target/scala-0.28/classes ...
[error] -- Error: /Users/rssh/tests/dotty/assert-in-print/src/main/scala/x/Main.scala:11:14 
[error] 11 |   X.printType( { Await.ready(latch(3) , 1 second) } )
[error]    |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]    |Exception occurred while executing macro expansion.
[error]    |scala.MatchError: Skolem(249706902) (of class dotty.tools.dotc.core.Types$SkolemType)
[error]    |	at scala.tasty.reflect.ExtractorsPrinter$Buffer.visitType(ExtractorsPrinter.scala:227)
[error]    |	at scala.tasty.reflect.ExtractorsPrinter.showTypeOrBounds(ExtractorsPrinter.scala:11)
[error]    |	at scala.tasty.Reflection$TypeOrBoundsOps$.extension_showExtractors(Reflection.scala:1348)
[error]    |	at scala.tasty.reflect.SourceCodePrinter$Buffer.printType(SourceCodePrinter.scala:1225)
[error]    |	at scala.tasty.reflect.SourceCodePrinter$Buffer.printTypeOrBound(SourceCodePrinter.scala:1068)
[error]    |	at scala.tasty.reflect.SourceCodePrinter.showTypeOrBounds(SourceCodePrinter.scala:16)
[error]    |	at scala.tasty.Reflection$TypeOrBoundsOps$.extension_showWith(Reflection.scala:1356)
[error]    |	at scala.tasty.Reflection$TypeOrBoundsOps$.extension_show(Reflection.scala:1352)
[error]    |	at x.X$.printTypeImpl(X.scala:13)
[error]    |
[error]    | This location contains code that was inlined from Main.scala:11
[error] one error found
[error] (Compile / compileIncremental) Compilation failed
[error] Total time: 2 s, completed 30 Aug 2020, 21:36:08

[rssh]

match-error-on-print-scolem-type.tar.gz
(ful sbt project)

[smarter]

The tasty pickler just unwraps skolems so I guess the tasty-reflect printer should do the same (that won't always give you something that passes the typechecker but that's not the only situation where you have a type that cannot be represented in source code) /cc @nicolasstucki