String.concat: def of Base
Import: import Base
Lines 2174-2179 of Base/base.bend: https://jend.leeeet.dev/read.txt?path=Base/base.bend&start_line=2174&end_line=2179

import Base

def String.concat(xs: List<&2, String>) -> String:
  match xs:
    case Nil{}:
      SNil{}
    case h <> t:
      String.append(h, String.concat(t))

Uses (3):
  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.append