Evaluation error of arrays in comprehension assignment

[CervEdin]

If I use assignment of arrays in comprehensions like this

array[int, int] of int: foos = [| 1, 0 |];

output [
  show([ r[1] | t=foos, i in index_set_1of2(t), r=t[i, ..] ]), % error
  show([ r[1] | i in index_set_1of2(foos), t=foos, r=t[i, ..] ]), % error
  show([ r[1] | i in 1..1, t=foos, r=t[i, ..] ]), % error
  "\n",
];

playground.mzn

I end up with

MiniZinc: evaluation error: index_set: wrong dimension

in MiniZinc 2.8.4+
in MiniZinc 2.8.3-
it's instead

Error: evaluation error: arrays of arrays not supported

Possibly related to issue #807

[CervEdin]

interestingly, this is OK

  show([ r | i in index_set_1of2(foos), t=foos, r=t[i, 1] ]), % OK

but this is not

  show([ r | t=foos, i in index_set_1of2(t), r=t[i, 1] ]), % error