Scala reflection API is not thread safe

[xuwei-k]

https://issues.scala-lang.org/browse/SI-6240

https://github.com/typelevel/wartremover/blob/v0.9/src/main/scala/wartremover/Plugin.scala#L36

java.lang.UnsupportedOperationException: tail of empty list
    at scala.collection.immutable.Nil$.tail(List.scala:339)
    at scala.collection.immutable.Nil$.tail(List.scala:334)
    at scala.reflect.internal.SymbolTable.popPhase(SymbolTable.scala:172)
    at scala.reflect.internal.Symbols$Symbol.unsafeTypeParams(Symbols.scala:1477)
    at scala.reflect.internal.Symbols$TypeSymbol.tpe(Symbols.scala:2777)
    at scala.reflect.internal.Mirrors$Roots$RootPackage$.<init>(Mirrors.scala:268)
    at scala.reflect.internal.Mirrors$Roots.RootPackage$lzycompute(Mirrors.scala:267)
    at scala.reflect.internal.Mirrors$Roots.RootPackage(Mirrors.scala:267)
    at scala.reflect.internal.Mirrors$Roots.RootPackage(Mirrors.scala:245)
    at scala.reflect.internal.Mirrors$RootsBase.init(Mirrors.scala:238)
    at scala.reflect.runtime.JavaMirrors$class.createMirror(JavaMirrors.scala:34)
    at scala.reflect.runtime.JavaMirrors$class.runtimeMirror(JavaMirrors.scala:61)
    at scala.reflect.runtime.JavaUniverse.runtimeMirror(JavaUniverse.scala:12)
    at scala.reflect.runtime.JavaUniverse.runtimeMirror(JavaUniverse.scala:12)
    at org.brianmckenna.wartremover.Plugin.processOptions(Plugin.scala:36)

[OlegYch]

any idea how to workaround this?