class PowerAssert::Parser

def collect_paths(idents, prefixes = [[]], index = 0)
  if index < idents.length
    node = idents[index]
    if node.kind_of?(Branch)
      prefixes = node.flat_map {|n| collect_paths(n, prefixes, 0) }
    else
      prefixes = prefixes.map {|prefix| prefix + [node] }
    end
    collect_paths(idents, prefixes, index + 1)
  else
    prefixes
  end
end