All is a wrapper for NewTypeSet(typ).All(fn).

Any is a wrapper for NewTypeSet(typ).Any(fn).

CoreType is a wrapper for NewTypeSet(typ).CoreType().

Dereference returns a pointer's element type; otherwise it returns T.

DereferenceR returns a pointer's element type; otherwise it returns T.

FlattenFields recursively flattens T and embedded structs, returning a list of fields.

OPT(dh): IsType is kind of expensive; should we really use it?.