"~string int ~string int",
		"myInt int myInt int",
		"~string ~int ~string ~int",
		"myInt ~int ~int ∅",
	} {
		args := split(test, 4)
		x := testTerm(args[0])
		y := testTerm(args[1])
		want1 := testTerm(args[2])
		want2 := testTerm(args[3])
		if got1, got2 := x.union(y); !got1.equal(want1) || !got2.equal(want2) {
			t.Errorf("%v.union(%v) = %v, %v; want %v, %v", x, y, got1, got2, want1, want2)
		}
	}

func maketl(s string) termlist {
	s = strings.ReplaceAll(s, " ", "")
	names := strings.Split(s, "|")
	r := make(termlist, len(names))
	for i, n := range names {
		r[i] = testTerm(n)
	}
	return r
}

func TestTermlistAll(t *testing.T) {
	if !allTermlist.isAll() {
		t.Errorf("allTermlist is not the set of all types")
	}
}

func TestTermlistString(t *testing.T) {