t.Errorf("insertBeforeFunc: want %+v but got %+v", c.applied, applied)
			}

			// insertAfterFunc
			got, applied = insertAfterFunc(slices.Clone(c.input), f)
			if !slices.Equal(c.insertAfter, got) {
				t.Errorf("insertAfterFunc: want %+v but got %+v", c.insertAfter, got)
			}
			if c.applied != applied {
				t.Errorf("insertAfterFunc: want %+v but got %+v", c.applied, applied)
			}
		})
	}

	}

	s = append(s, toInsert) // for grow the cap
	copy(s[idx+1:], s[idx:])
	s[idx] = toInsert

	return s, true
}

// insertAfterFunc find and insert an element after the found element.
// If the f function returns true, the returned value will be inserted after the found element.
func insertAfterFunc[E any](s []E, f func(e E) (bool, E)) ([]E, bool) {
	var toInsert E
	idx := -1
	for k, v := range s {
		if ok, r := f(v); ok {