func f[T any](R[T]) {}

type R[T any] interface {
	m(R[T])
}

type R1 struct{}

func (R1) m(R[int]) {}

// Test case from issue.

func _() {
	r := newTestRules()
	NewSet(r)
	r2 := newTestRules2()
	NewSet(r2)
}

type Set[T any] struct {
	rules Rules[T]
}

func NewSet[T any](rules Rules[T]) Set[T] {
	return Set[T]{
		rules: rules,
	}
}

func (s Set[T]) Copy() Set[T] {