wrong variable substitution in conditional assignment with refc GC

[hamidb80]

Example

block correct:
  var point = (x: 10, y: 4)

  point = (x: point.y, y: - point.x)
  echo point

block wrong:
  var point = (x: 10, y: 4)

  point = 
    if true: (x: point.y, y: - point.x)
    else: point

  echo point

Current Output

(x: 4, y: -10)
(x: 4, y: -4)

Expected Output

(x: 4, y: -10)
(x: 4, y: -10)

Additional Information

$ nim -v
Nim Compiler Version 1.5.1 [Windows: amd64]
Compiled at 2021-06-20
Copyright (c) 2006-2021 by Andreas Rumpf

[hamidb80]

it does work for ARC and ORC but not other GCs