# the create is legal since r1 and r2 are structurally equiv.  The
# invocation of z.f1, also legal, really invokes f2 in the instance of r2.
# Works fine under v1.1 (with output `r2 88'), but not under 91d or 91f:

resource r1
  op f1(int x)
body r1()
  proc f1(x)  {
    write("r1", x)
  }
end
resource r2
  op f2(int x)
body r2()
  proc f2(x)  {
    write("r2", x)
  }
end
resource main()
  import r1, r2
    cap r1  z 
    z = create r2()
    z.f1(88)
end