def append_nil
import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/argon2/phc.bend as Phcimport Base
1342def append_nil(+x: String) -> {String.append(x, SNil{}) == x : String}:
1343 match x:
1344 case SNil{}:
1345 {==}
1346 case SCon{+h, +t}:
1347 Equal.cong(String, String, z => SCon{h, z}, String.append(t, SNil{}), t, append_nil(t))