type
  Foo = object
    a, b, c, d: ref int

# compiles to
# (NI is `long long int` on my machine - defined in nimbase.h)

struct  Foo_gTstHTAF3QSjpQUtVcW29bQ  {
  NI* a;
  NI* b;
  NI* c;
  NI* d;
};