Passing a generic iterator to another iterator doesn't seem to work

[jovial]

type
  A[T] = iterator(x: T): T {.gcsafe, closure.}
  B = iterator(y: A[int], z: int): int {.gcsafe, closure.}

iterator aimp[T](x: T): T {.gcsafe, closure.} =
  var total = 0
  while (total < 100):
    yield total
    total += x

iterator bimp(y: A[int], z:int): int {.gcsafe, closure.} =
  #var x = y(z)
  for i in y(z):
    yield i

for x in aimp[int](3):
  echo x

var y = aimp[int]
var z = bimp
for x in z(y):
  echo x

This gives:

/tmp/aporia/a16.nim(23, 12) Error: type mismatch: got (int)
but expected one of:
system.items(a: cstring): iter[char]
...

Uncommenting #var x = y(z), yields:

/tmp/aporia/a16.nim(31, 10) Error: type mismatch: got (iterator (int): int{.closure, gcsafe.})
but expected one of:
iterator (A[int], int): int{.closure, gcsafe.}

which seems incorrect.

[ringabout]

Original codes are not correct:

var y = aimp[int]
var z = bimp
for x in z(y):
  echo x

It should give another parameters(int type) to z. For example:

var y = aimp[int]
var z = bimp
for x in z(y, 1):
  echo x

which works since Nim v1.2.6