MatchError in TPrint macro expansion on PolyType

[mrdziuban]

I'm seeing a MatchError thrown during compilation when TPrintImpl encounters a PolyType. The full error is:

exception during macro expansion: 
scala.MatchError: [+A]Playground.Foo[A] (of class scala.reflect.internal.Types$PolyType)
	at pprint.TPrintLowPri$.typePrintImplRec0(TPrintImpl.scala:151)
	at pprint.TPrintLowPri$.typePrintImplRec(TPrintImpl.scala:32)
	at pprint.TPrintLowPri$.$anonfun$typePrintImplRec0$7(TPrintImpl.scala:103)
	at scala.collection.immutable.List.map(List.scala:246)
	at pprint.TPrintLowPri$.added$2(TPrintImpl.scala:103)
	at pprint.TPrintLowPri$.printArgs$1(TPrintImpl.scala:106)
	at pprint.TPrintLowPri$.typePrintImplRec0(TPrintImpl.scala:200)
	at pprint.TPrintLowPri$.typePrintImplRec(TPrintImpl.scala:32)
	at pprint.TPrintLowPri$.typePrintImpl(TPrintImpl.scala:21)

I was able to put together a minimal reproduction in scastie here that mirrors how this error was triggered in my codebase. For context, this occurs when using PPrint 0.7.1 on scala 2.13.8.

Thank you for all your work on this library!

[ccarlile]

I experienced this with the Ammonite Repl 2.5.1 (Scala 2.13.8 Java 17.0.1) and fs2 version 3.2.4:

@ Stream.emit("hello")
cmd1.sc:8: exception during macro expansion:
scala.MatchError: [x]fs2.Pure[x] (of class scala.reflect.internal.Types$PolyType)
	at pprint.TPrintLowPri$.typePrintImplRec0(TPrintImpl.scala:151)
	at pprint.TPrintLowPri$.typePrintImplRec(TPrintImpl.scala:32)
	at pprint.TPrintLowPri$.$anonfun$typePrintImplRec0$7(TPrintImpl.scala:103)
	at scala.collection.immutable.List.map(List.scala:246)
	at pprint.TPrintLowPri$.added$2(TPrintImpl.scala:103)
	at pprint.TPrintLowPri$.printArgs$1(TPrintImpl.scala:106)
	at pprint.TPrintLowPri$.typePrintImplRec0(TPrintImpl.scala:200)
	at pprint.TPrintLowPri$.typePrintImplRec(TPrintImpl.scala:32)
	at pprint.TPrintLowPri$.typePrintImpl(TPrintImpl.scala:21)

          .print(res1, "res1", _root_.scala.None)
                ^
Compilation Failed