GraphQL: NPE with VALUES block

[Aklakan]

The following query fails because the variable analysis of a VALUES block fails. Explicitly declaring the variables works.

query test @debug {
  locations(limit: 5) @pattern(of: """
     VALUES ?x {
        <urn:s1> <urn:s2>
     }
     """) { # Works when adding from: "x", to: "x"
    id @bind(of: "?x")
  }
}