Eliminates syntactic references to Java packages, so that there's no chance they accidentally end up in the backend.
Check what the phase achieves, to be called at any point after it is finished.
Is the given tree a syntactic reference to a Java package?
A name given to the
Phase that can be used to debug the compiler. For
instance, it is possible to print trees after a given phase using:
$ ./bin/dotc -Xprint:<phaseNameHere> sourceFile.scala