Dgraph do not accept valid GraphQL with inverse @dgraph directive

[Luscha]

What version of Dgraph are you using?

Master

Have you tried reproducing the issue with the latest release?

v20.07

What is the hardware spec (RAM, OS)?

Steps to reproduce the issue (command/config used to run Dgraph).

Add this predicate to dgraph Schema

Object.owner uid @reverse .

then try to push the following GraphQL Schema

type Object {
   ownedBy: Person @dgraph(pred: "Object.owner")
}

type BusinessMan implements Person {
  companyName: String
}

interface Person {
    name: String
    owns: [Object] @dgraph(pred: "~Object.owner")
}

Expected behaviour and actual result.

The schema should be valid and accepted by dgraph

but dgraph refuses the schema with the following error:

couldn't rewrite mutation updateGQLSchema because input:1: Type Object; Field ownedBy: should be of type BusinessMan to be compatible with @dgraph reverse directive but is of type Person.\n