scala-xml repo has sbt console errors

[ashawley]

Seems after merging #312, starting the console in sbt causes issues:

> console
[info] Starting scala interpreter...
Welcome to Scala 2.12.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_40).
Type in expressions for evaluation. Or try :help.

scala> <console>:5: error: object tools is not a member of package scala
         var value: scala.tools.nsc.interpreter.IMain = _
                          ^
<console>:6: error: object tools is not a member of package scala
         def set(x: _root_.scala.Any) = value = x.asInstanceOf[scala.tools.nsc.interpreter.IMain]

If I disable the sbt-dotty plugin, it doesn't happen.

[SethTisue]

@smarter your dept, or can you recommend someone else from the Dotty team who could look at it?

[smarter]

sbt-dotty tries very carefully to not affect non-dotty projects, but turns out that we're doing it wrong and I don't know if there's a way to do it right: https://gitter.im/sbt/sbt-contrib?at=5cea7db4ad024978c62ff208. I'll look into it.

[ashawley]

Thanks for looking into it.

These aren't fatal errors. The Scala REPL does seem to work. However the errors would seem to hint at other problems. For one, we can no longer use XML literals:

scala> <xml/>
<console>:12: error: To compile XML syntax, the scala.xml package must be on the classpath.
Please see https://github.com/scala/scala-xml for details.
       <xml/>
       ^

It seems this is because the library code is generally unreachable:

scala> scala.xml.XML.loadString("<xml/>")
<console>:12: error: object xml is not a member of package scala
       scala.xml.XML.loadString("<xml/>")

Using the JVM sub-project, xml/console will work as a workaround:

> xml/console
[info] Starting scala interpreter...
Welcome to Scala 2.12.8 (Java HotSpot(TM) 64-Bit Server VM, Java 11.0.2).
Type in expressions for evaluation. Or try :help.

<console>:5: error: object tools is not a member of package scala
         var value: scala.tools.nsc.interpreter.IMain = _
                          ^
<console>:6: error: object tools is not a member of package scala
         def set(x: _root_.scala.Any) = value = x.asInstanceOf[scala.tools.nsc.interpreter.IMain]
                                                                     ^
scala> <xml/>
res0: scala.xml.Elem = <xml/>

[smarter]

Fixed by #314.

[SethTisue]

@eed3si9n maybe you should take a gander at dotty-staging/dotty@d46235b

[smarter]

@SethTisue He reviewed the PR already :)

[eed3si9n]

@SethTisue Yea. Both Dale and I have reviewed scala/scala3#6577

[eed3si9n]

However, I do appreciate the "hey Eugene maybe you should look at this" signals.

[SethTisue]

oh sorry, I only looked at the commit without looking at the PR :-)