type
FieldListSet
FieldListSet records field lists a definition traversal has entered. A shared definition passes the same slice wherever it is placed, so a traversal that enters each list once does work proportional to definitions.
Full signature
type FieldListSet map[*Field]struct{}Methods
FieldListSet.Add()Add reports whether fields were not yet in the set, adding them. An empty list is never recorded and always reports true.