Errors:
- Not supported
- Only * is supported
- Expected * in *, but got *
- Divergent type in (construct), (location 1), (location 2)
- Unknown field
- Unbounded variable
- Different variable
- Different domain
- * is not subclass of *
- Type not equal
- Incorrect number of parameters

GlobalContext:
- Separate from typedefs
- Interact with python intepreter to get data
- Primitive Type Instance List
- Symbol Table (readable, ever defined)
- TypeVar definition stack
- Provide subst, inv_subst, blablabla
- Cache type var method lookup (dropped when related assumptions are changed)