Registers a dummy class for sbt's incremental compilation.
Registers a dummy class for sbt's incremental compilation.
If a compiler phase creates a new named (module) class/trait after the phase
ExtractAPI, it must register that class for sbt's incremental compilation
on its own, lest crashes happen. In theory, the full API of the class needs
to be constructed, but if the class is never accessed by Scala source code,
a dummy empty class can be registered instead, using this method.
