TreeUnpickler

Define the expected format of the tasty bytes

• TopLevel: Tasty that contains a full class nested in its package
• Term: Tasty that contains only a term tree
• TypeTree: Tasty that contains only a type tree or a reference to a type

An enumeration indicating which subtrees should be added to an OwnerTree.

A marker value used to detect cyclic reference while unpickling definitions.