types package:boltzmann-samplers
Structure of types and their pointings (up to
points, initially
0)
Primitive types and empty types are mapped to an empty constructor
list, and can be distinguished using
dataTypeRep on the
SomeData associated to it by
xedni.
The integer is a multiplicity which can be > 1 for pointings.
Find all types that may be types of subterms of a value of type
a.
This will loop if there are infinitely many such types.