genericAssignAux runtime error

[timotheecour]

reduced a bit from a case mentioned in forum /cc @xflywind

Hi, could anybody help me understand the error here? https://play.nim-lang.org/#ix=2LRt

Example

when true:
  import tables, times
  type
    Shift* = object
      date*: DateTime
  type
    Data* = object
      shifts*: OrderedTable[int, Shift]


  var shifts = initOrderedTable[int, Shift]()
  var data = Data(shifts: shifts)

Current Output

/Users/timothee/git_clone/nim/timn/tests/nim/all/t11694.nim(76) t11694
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(175) genericSeqAssign
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(139) genericAssign
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(100) genericAssignAux
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(128) genericAssignAux
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(26) genericAssignAux
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(22) genericAssignAux
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(128) genericAssignAux
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(22) genericAssignAux
/Users/timothee/git_clone/nim/Nim_devel/lib/system/assign.nim(125) genericAssignAux
/Users/timothee/git_clone/nim/Nim_devel/lib/system/fatal.nim(53) sysFatal
Error: unhandled exception: invalid object assignment [ObjectAssignmentDefect]

Expected Output

works

Additional Information

devel 1.5.1 61fd19c

• links: https://forum.nim-lang.org/t/7378#46755

[ringabout]

Reduced examples:

import std/times

type
  Data = object
    shifts*: seq[DateTime]

var shifts = newSeq[DateTime](5)
var data = Data(shifts: shifts)

[timotheecour]

further reduced without any import:

when true:
  type
    A = object of RootObj
      a0: string
    B = object
      b0: seq[A]
  var c = newSeq[A](2)
  var d = B(b0: c)

=> #16721