# Is there a way to make Nim's object display checks ABI-stable?

# to make sure for example that

# `a.nim`, `nim c --app:lib a`
type
  BaseType = object of RootObj
  SubType = object of BaseType

proc foo(x: ptr BaseType) {.exportc, dynlib.} =
  if x of SubType: echo "sub"
  else: echo "base"
# `b.nim`, `LD_LIBRARY_PATH=. nim c -r b`
type
  BaseType = object of RootObj
  SubType = object of BaseType

proc foo(x: ptr BaseType) {.importc, dynlib: "liba.so".}

let x = create SubType
x[] = SubType()

foo x

dealloc x
# prints "sub", instead of "base" like it currently does?