Check.args.dups: def of shake@0.7.0.0
Import: import shake@0.7.0.0/src/check.bend as Check
Lines 60-79 of shake@0.7.0.0/src/check.bend: https://jend.leeeet.dev/read.txt?path=shake@0.7.0.0/src/check.bend&start_line=60&end_line=79

import Base
import shake@0.7.0.0/src/cli.bend as C

# each argument's name and spellings against the earlier ones', and its
# default against its choices
def args.dups(
  args: List<&2, C.Arg>,
  +path: List<&2, String>,
  +names: List<&2, String>,
  +shorts: List<&2, String>,
  +longs: List<&2, String>
) -> List<&2, SpecErr>:
  match args:
    case Nil{}:
      []
    case Con{hh, tt}:
      C.Arg{+name, +short, +long, _k, _h, _r, C.Fallback{_e, dflt}, +cs} = hh
      both(one(List.contains(~String, ~String.eq, names, name), SameName{path, name}),
        both(one(spelled.seen(short, shorts), SameShort{path, C.text.of(short, "")}),
          both(one(spelled.seen(long, longs), SameLong{path, C.text.of(long, "")}),
            both(args.default(dflt, cs, path, name),
              args.dups(tt, path, name <> names, spelled.add(short, shorts),
                spelled.add(long, longs))))))

Uses (13):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.contains
  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=shake@0.7.0.0/src/check.bend&name=SpecErr
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/check.bend&name=args.default
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/check.bend&name=both
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/check.bend&name=one
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/check.bend&name=spelled.add
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/check.bend&name=spelled.seen
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/cli.bend&name=Arg
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/cli.bend&name=Fallback
  https://jend.leeeet.dev/definition.txt?path=shake@0.7.0.0/src/cli.bend&name=text.of