code: public Type cvarLowerBound(Type t) {
          if (t.hasTag(TYPEVAR)) {
              TypeVar v = (TypeVar) t.unannotatedType();
              return v.isCaptured() ? cvarLowerBound(v.getLowerBound()) : v;
          }
          else return t.unannotatedType();
      }
docs: Get a capture variable's lower bound, returning other types unchanged.
  @param t a type