var ref param doesn't work when it comes from an object member

[krux02]

Example

type
  MyObjectRef = ref object
    a,b: int

  MyContainerObject = ref object
    member: MyObjectRef

proc foobar(dst: var MyObjectRef) =
  dst = new(MyObjectRef)
  dst.a = 123
  dst.b = 321

proc test() =
  # when it comes from a var, it works
  var y: MyObjectRef
  foobar(y)
  echo y != nil
  # when it comes from a member, it fails on VM
  var x = new(MyContainerObject)
  foobar(x.member)
  echo x.member != nil

test()
static:
  test()

Current Output

Hint: scratch [Processing]
true
false
CC: stdlib_system.nim
CC: scratch.nim
Hint:  [Link]
Hint: operation successful (21928 lines compiled; 1.042 sec total; 25.594MiB peakmem; Dangerous Release Build) [SuccessX]
Hint: /tmp/scratch  [Exec]
true
true

Expected Output

Hint: scratch [Processing]
true
true
CC: stdlib_system.nim
CC: scratch.nim
Hint:  [Link]
Hint: operation successful (21928 lines compiled; 1.042 sec total; 25.594MiB peakmem; Dangerous Release Build) [SuccessX]
Hint: /tmp/scratch  [Exec]
true
true

Additional Information

• Non ref parameters work fine.
• This causes problems in my json macro
  

  Nim/lib/pure/json.nim

  Line 1051 in 2ccd1c3

  dst = new(ref T)