Unable to conversion-gen conversions that require a conversion.Scope

Some functions autogenerated by conversion-gen produce code that looks like this:

func autoConvert_v1alpha1_Something_To_v1alpha2_Something(in *Something, out *v1alpha2.Something, s conversion.Scope) error {
  // normal convertible fields
  out.X = in.X
  // TODO: Inefficient conversion - can we improve it?
  if err := s.Convert(&in.SomeField, &out.SomeField, 0); err != nil {
    return err
  }
  return nil
}

The "inefficient conversion" can happen in a few different situations; in this case, it's because SomeField is a struct that lives in a package outside of the one where I'm generating conversions. Due to https://github.com/kubernetes/code-generator/issues/94 (assuming there isn't a workaround), even if there were conversion functions for SomeField, conversion-gen isn't able to see & use them.

We presumably need access to a conversion.Scope in our ConvertTo/ConvertFrom implementations, but these are member functions on the types, and I haven't yet found any way to get access to a Scope (this appears to have a single, unexported implementation that is used internally by the conversion machinery code).

Anyone know of a way to use generated conversion functions that need a Scope?

Start by tracing the conversion-gen output shown in the issue and the conversion.Scope implementation used by the conversion machinery. Then inspect how ConvertTo and ConvertFrom implementations are expected to access a scope, along with the limitation described in code-generator issue 94. Done means establishing a supported way to use generated conversions requiring a Scope, or documenting that no such path exists.