Concat.walk: def of bolt@1.27.0.0
Import: import bolt@1.27.0.0/src/rules/suspicious/concat.bend as Concat
Lines 210-232 of bolt@1.27.0.0/src/rules/suspicious/concat.bend: https://jend.leeeet.dev/read.txt?path=bolt@1.27.0.0/src/rules/suspicious/concat.bend&start_line=210&end_line=232

import Base
import bolt@1.27.0.0/src/finding.bend as F
import bolt@1.27.0.0/src/syntax/lex.bend as Lex
import bolt@1.27.0.0/src/syntax/tree.bend as Tree
import bolt@1.27.0.0/src/rules/calls.bend as Calls
import bolt@1.27.0.0/src/lazy/lazy.bend as Lazy

# every self-call's arguments, with the lets in scope
def walk(
  nn: Tree.Node,
  +name: String,
  +params: List<&2, String>,
  +lets: List<&2, Let>,
  +path: String
) -> List<&2, F.Finding>:
  match nn:
    case Tree.NCons{Tree.Leaf{Lex.Tok{k, +t, l, c}}, Tree.NCons{Tree.Group{Lex.Tok{_, +o, _, _}, +kids, _}, rest}}:
      +me = Bool.and(String.eq(o, "("), String.eq(t, name))
      List.concat(&2, F.Finding, [
        Lazy.stop(List<&2, F.Finding>, Bool.not(me), [], _u => hits(Calls.args(kids), params, lets, path, [])),
        walk(kids, name, params, lets, path), walk(rest, name, params, lets, path)])
    case Tree.NCons{Tree.Group{open, kids, close}, rest}:
      List.concat(&2, F.Finding, [walk(kids, name, params, lets, path), walk(rest, name, params, lets, path)])
    case Tree.NCons{Tree.Stmt{kind, +kids, body}, rest}:
      List.concat(&2, F.Finding, [walk(kids, name, params, lets, path), walk(body, name, params, lets, path),
        walk(rest, name, params, after(kind, kids, lets), path)])
    case Tree.NCons{h, rest}:
      walk(rest, name, params, lets, path)
    case other:
      Nil{}

Uses (14):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.not
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.concat
  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=bolt@1.27.0.0/src/finding.bend&name=Finding
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/lazy/lazy.bend&name=stop
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/rules/calls.bend&name=args
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/rules/suspicious/concat.bend&name=Let
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/rules/suspicious/concat.bend&name=after
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/rules/suspicious/concat.bend&name=hits
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/syntax/lex.bend&name=Tok
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/syntax/tree.bend&name=Node