def internal_append_nil
import bend-mathlib@0.8.1.0/string.bend as Stringimport Base
11def internal_append_nil(a: String) -> {a == String.append(a, SNil{}) : String}:
12 match a:
13 case SNil{}:
14 {==}
15 case SCon{+h, +t}:
16 %internal_append_nil(t) : {SCon{h, t} == SCon{h, _} : String}
17 {==}