Lock.seen.holds: def of ezx@1.13.0.0
Import: import ezx@1.13.0.0/src/lock/lock.bend as Lock
Lines 411-420 of ezx@1.13.0.0/src/lock/lock.bend: https://jend.leeeet.dev/read.txt?path=ezx@1.13.0.0/src/lock/lock.bend&start_line=411&end_line=420

import Base

# whether a name is already among the ones a walk has seen. Base's
# `List.contains` applies an erased equality, which Bend's termination check
# cannot see through; this scan is structural. `any.step` is what lets it
# stop at the name it was looking for instead of reading past it.
def seen.holds(xs: List<&2, String>, +needle: String) -> Bool:
  match xs:
    case []:
      False{}
    case +h <> t:
      any.step(String.eq(h, needle), _u => seen.holds(t, needle))

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.eq
  https://jend.leeeet.dev/definition.txt?path=ezx@1.13.0.0/src/lock/lock.bend&name=any.step