Error `Expected TermName but got example.MyObject[$]._$_$_$_$`

[mrdziuban]

When trying to load a package's declarations I get the error below. Unfortunately I haven't been able to come up with a minimal reproduction, but I'll keep trying.

tastyquery.Exceptions$TastyFormatException: Expected TermName but got example.MyObject[$]._$_$_$_$
	at tastyquery.reader.tasties.TastyUnpickler$NameTable.simple(TastyUnpickler.scala:46)
	at tastyquery.reader.tasties.TastyUnpickler.readName(TastyUnpickler.scala:95)
	at tastyquery.reader.tasties.TastyUnpickler.readUnsignedName(TastyUnpickler.scala:97)
	at tastyquery.reader.tasties.TastyUnpickler.$anonfun$1(TastyUnpickler.scala:154)
	at tastyquery.reader.tasties.TastyReader.until(TastyReader.scala:141)
	at tastyquery.reader.tasties.TastyUnpickler.readNameContents(TastyUnpickler.scala:154)
	at tastyquery.reader.tasties.TastyUnpickler.$init$$$anonfun$1(TastyUnpickler.scala:191)
	at tastyquery.reader.tasties.TastyUnpickler.$init$$$anonfun$adapted$1(TastyUnpickler.scala:191)
	at tastyquery.reader.tasties.TastyReader.until(TastyReader.scala:141)
	at tastyquery.reader.tasties.TastyUnpickler.<init>(TastyUnpickler.scala:191)
	at tastyquery.reader.tasties.TastyUnpickler.<init>(TastyUnpickler.scala:90)
	at tastyquery.reader.Loaders$PackageLoadingInfo.doLoadTasty(Loaders.scala:173)
	at tastyquery.reader.Loaders$PackageLoadingInfo.tryLoadRoot(Loaders.scala:107)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadAllRoots$$anonfun$1$$anonfun$1(Loaders.scala:47)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.immutable.List.foreach(List.scala:334)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadAllRoots$$anonfun$1(Loaders.scala:47)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadingRoots(Loaders.scala:92)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadAllRoots(Loaders.scala:46)
	at tastyquery.Symbols$.tastyquery$Symbols$PackageSymbol$$_$declarations$$anonfun$1(Symbols.scala:1929)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at tastyquery.Symbols$PackageSymbol.loadingNewRoots(Symbols.scala:1876)
	at tastyquery.Symbols$PackageSymbol.declarations(Symbols.scala:1929)
	at rs$line$3$.$init$$$anonfun$1(rs$line$3:1)
	at scala.util.Try$.apply(Try.scala:217)
	at rs$line$3$.<clinit>(rs$line$3:1)
	at rs$line$3.t(rs$line$3)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at dotty.tools.repl.Rendering.$anonfun$4(Rendering.scala:120)
	at scala.Option.flatMap(Option.scala:283)
	at dotty.tools.repl.Rendering.valueOf(Rendering.scala:120)
	at dotty.tools.repl.Rendering.renderVal(Rendering.scala:160)
	at dotty.tools.repl.ReplDriver.$anonfun$7(ReplDriver.scala:402)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.immutable.List.foreach(List.scala:334)
	at dotty.tools.repl.ReplDriver.extractAndFormatMembers$1(ReplDriver.scala:402)
	at dotty.tools.repl.ReplDriver.renderDefinitions$$anonfun$2(ReplDriver.scala:440)
	at scala.Option.map(Option.scala:242)
	at dotty.tools.repl.ReplDriver.renderDefinitions(ReplDriver.scala:439)
	at dotty.tools.repl.ReplDriver.compile$$anonfun$2(ReplDriver.scala:342)
	at scala.util.Either.fold(Either.scala:197)
	at dotty.tools.repl.ReplDriver.compile(ReplDriver.scala:324)
	at dotty.tools.repl.ReplDriver.interpret(ReplDriver.scala:283)
	at dotty.tools.repl.ReplDriver.loop$1(ReplDriver.scala:196)
	at dotty.tools.repl.ReplDriver.runUntilQuit$$anonfun$1(ReplDriver.scala:199)
	at dotty.tools.repl.ReplDriver.withRedirectedOutput(ReplDriver.scala:238)
	at dotty.tools.repl.ReplDriver.runBody$$anonfun$1(ReplDriver.scala:212)
	at dotty.tools.runner.ScalaClassLoader$.asContext(ScalaClassLoader.scala:80)
	at dotty.tools.repl.ReplDriver.runBody(ReplDriver.scala:212)
	at dotty.tools.repl.ReplDriver.runUntilQuit(ReplDriver.scala:199)
	at xsbt.ConsoleInterface.run(ConsoleInterface.java:52)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at sbt.internal.inc.AnalyzingCompiler.invoke(AnalyzingCompiler.scala:329)
	at sbt.internal.inc.AnalyzingCompiler.console(AnalyzingCompiler.scala:233)
	at sbt.Console.console0$1(Console.scala:65)
	at sbt.Console.$anonfun$apply$5(Console.scala:75)
	at sbt.Run$.executeSuccess(Run.scala:187)
	at sbt.Console.$anonfun$apply$4(Console.scala:75)
	at sbt.internal.util.Terminal.withRawInput(Terminal.scala:146)
	at sbt.internal.util.Terminal.withRawInput$(Terminal.scala:144)
	at sbt.internal.util.Terminal$ProxyTerminal$.withRawInput(Terminal.scala:434)
	at sbt.Console.$anonfun$apply$3(Console.scala:75)
	at sbt.internal.util.Terminal$TerminalImpl.withRawOutput(Terminal.scala:1038)
	at sbt.internal.util.Terminal$ProxyTerminal$.withRawOutput(Terminal.scala:473)
	at sbt.Console.apply(Console.scala:72)
	at sbt.Console.apply(Console.scala:50)
	at sbt.Console.apply(Console.scala:42)
	at sbt.Defaults$.$anonfun$consoleTask$1(Defaults.scala:2279)
	at sbt.Defaults$.$anonfun$consoleTask$1$adapted(Defaults.scala:2265)
	at scala.Function1.$anonfun$compose$1(Function1.scala:49)
	at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:63)
	at sbt.std.Transform$$anon$4.work(Transform.scala:69)
	at sbt.Execute.$anonfun$submit$2(Execute.scala:283)
	at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:24)
	at sbt.Execute.work(Execute.scala:292)
	at sbt.Execute.$anonfun$submit$1(Execute.scala:283)
	at sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
	at sbt.CompletionService$$anon$2.call(CompletionService.scala:65)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)

[mrdziuban]

This seems to be related to lazy implicits. With some refactoring in my code I'm now getting this error:

tastyquery.Exceptions$TastyFormatException: Expected a signature name but got example.MyObject$._$_$_$_$[unique $_lazy_implicit_$ 2]
	at tastyquery.reader.tasties.TastyUnpickler$NameTable.signatureName(TastyUnpickler.scala:78)
	at tastyquery.reader.tasties.TastyUnpickler.readSignatureName(TastyUnpickler.scala:120)
	at tastyquery.reader.tasties.TastyUnpickler.readNameContents(TastyUnpickler.scala:162)
	at tastyquery.reader.tasties.TastyUnpickler.$init$$$anonfun$1(TastyUnpickler.scala:191)
	at tastyquery.reader.tasties.TastyUnpickler.$init$$$anonfun$adapted$1(TastyUnpickler.scala:191)
	at tastyquery.reader.tasties.TastyReader.until(TastyReader.scala:141)
	at tastyquery.reader.tasties.TastyUnpickler.<init>(TastyUnpickler.scala:191)
	at tastyquery.reader.tasties.TastyUnpickler.<init>(TastyUnpickler.scala:90)
	at tastyquery.reader.Loaders$PackageLoadingInfo.doLoadTasty(Loaders.scala:173)
	at tastyquery.reader.Loaders$PackageLoadingInfo.tryLoadRoot(Loaders.scala:107)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadAllRoots$$anonfun$1$$anonfun$1(Loaders.scala:47)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.immutable.List.foreach(List.scala:334)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadAllRoots$$anonfun$1(Loaders.scala:47
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadingRoots(Loaders.scala:92)
	at tastyquery.reader.Loaders$PackageLoadingInfo.loadAllRoots(Loaders.scala:46)
	at tastyquery.Symbols$.tastyquery$Symbols$PackageSymbol$$_$declarations$$anonfun$1(Symbols.scala:1929)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at tastyquery.Symbols$PackageSymbol.loadingNewRoots(Symbols.scala:1876)
	at tastyquery.Symbols$PackageSymbol.declarations(Symbols.scala:1929)
	at bondlink.FindUnusedGivens$.symGivens(FindUnused.scala:182)
	at bondlink.FindUnusedGivens$.main(FindUnused.scala:69)
	at bondlink.FindUnusedGivens.main(FindUnused.scala)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)

[mrdziuban]

I finally managed to minimize this in https://github.com/mrdziuban/tasty-query-lazy-implicit-term-name, which contains the following code:

trait Foo[A, B]
object Foo {
  given inverse[A, B](using s: => Foo[B, A]): Foo[A, B] = new Foo[A, B] {}
}

object Test {
  val foo = summon[Foo[Int, String]]
}

as well as a test file that tries to read Test.foo using tasty-query.

Note that the result of the summon call in object Test is a bit odd as it recursively summons instances of Foo to satisfy
the inverse relationship constraint, i.e. the resulting instance is:

Foo.inverse[Int, String](
  Foo.inverse[String, Int](
    Foo.inverse[Int, String](... to infinity ...)
  )
)

Clearly Foo.inverse is kind of silly since it lets you summon an instance of Foo for any two unrelated types, but the compiler happily lets you write this code and generates valid TASTy for it, so it still feels like something that tasty-query should be able to handle.

What do you think @sjrd?

[sjrd]

Thanks for the minimization. I'll try to find some cycles for this next week.