Trouble with objectTypeDefTypes

[Sytten]

This is related to my plugin https://github.com/Sytten/nexus-shield
So I am trying to define a new objectType property and I honestly tried very hard to make it work, but the TypeName always gets overwritten by the incoming interface that you put as an input and the whole thing blows up to a basic string making the rest of the typing go down the toilet :)

So basically the generated code is:

interface NexusGenPluginTypeConfig<TypeName extends string> {
    /**
     * Default authorization rule to execute on all fields of this object
     */
    shield?: ShieldRule<TypeName, any>
  }

And I generate the interface using:

type ShieldRuleConfig<TypeName extends string, FieldName extends string> = {
  type?: TypeName;
  name?: string;
  cache?: ShieldCache;
  resolve: ShieldRuleFunction<TypeName, FieldName>;
};

export const ruleType = <TypeName extends string, FieldName extends string>(
  config: ShieldRuleConfig<TypeName, FieldName>
): ShieldRule<TypeName, FieldName> => {
  return new BaseRule<TypeName, FieldName>(config, config.resolve);
};

When I define the rules in the fields, I have no problem and the typing flows from the objectType into the ShieldRule, but for some reason in the object type it doesn't and it takes the string as the type.

Problem:

Similar situation for field (but works correctly):

It also works fine if I just accept a function like:

interface NexusGenPluginTypeConfig<TypeName extends string> {
    /**
     * Default authorization rule to execute on all fields of this object
     */
    shield?: (root: RootValue<TypeName>, args: ArgsValue<TypeName, FieldName>, ctx: GetGen<'context'>, info: GraphQLResolveInfo) => ShieldRuleResult | Promise<ShieldRuleResult>;
  }

But that is not really what I want to do because I miss some configuration.

Any idea is appreciated, maybe this is not doable with the current state of typescript :/
I might have to switch to a more function interface instead of OO based like I have currently.