PROOF.rev_twice: def of bend-osdev-bpf@0.1.0.0
Import: import bend-osdev-bpf@0.1.0.0/PROOF.bend as PROOF
Lines 514-516 of bend-osdev-bpf@0.1.0.0/PROOF.bend: https://jend.leeeet.dev/read.txt?path=bend-osdev-bpf@0.1.0.0/PROOF.bend&start_line=514&end_line=516

import Base

# reversing twice gives the list back
def rev_twice(-A: Data, +xs: List<&2, A>) -> {List.reverse.go(&2, A, List.reverse.go(&2, A, xs, Nil{}), Nil{}) == xs : List<&2, A>}:
  Equal.trans(List<&2, A>, List.reverse.go(&2, A, List.reverse.go(&2, A, xs, Nil{}), Nil{}), List.append(&2, A, xs, Nil{}), xs, rev_rr(A, xs, Nil{}, Nil{}), app_nil(A, xs))

Uses (6):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.trans
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.append
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.reverse.go
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bpf@0.1.0.0/PROOF.bend&name=app_nil
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bpf@0.1.0.0/PROOF.bend&name=rev_rr