lib/system.nim(1627, 7) Error: undeclared identifier: 'data'

[reactormonk]

Error:

test.nim(5, 32) Info: instantiation from here
lib/system.nim(1627, 7) Error: undeclared identifier: 'data'

Code:

import sets
proc product[T](x: openarray[seq[T]]): seq[seq[T]] =
  result = @[]

assert(toSet(product[int](@[])) == toSet(@[newSeq[int](0)]))

[reactormonk]

Found it. == for sets is broken.

toSet(@[1]) == toSet(@[1])