[New module system] Incorrect error on nested instantiation

[yav]

The following reports an error that P does not implement x but it does. The whole thing appears to work if the declaration of submodule M is outside of X

interface submodule I where
  x : [8]

submodule F where
  import interface submodule I
  y = x + 1

submodule P where
  x = 11

submodule X where
  submodule M = submodule F { submodule P }
  import submodule M

  z = y