whatever.ml

module Query1 = [%graphql
  {|
    query { 
      someFieldWithInterfaceType {
        id
        ...on ImplA {
          a_only
        }
        ...on ImplB {
          b_only
        }
      }
    }
  |}
]

module FragA = [%graphql
  {|
    fragment on ImplA {
      a_only
    }
  |}]

(* This should _ideally_ have the same type as Query1 *)
module Query2 = [%graphql
  {|
    query { 
      someFieldWithInterfaceType {
        id
        ...on ImplA {
          ...FragA
        }
        ...on ImplB {
          b_only
        }
      }
    }
  |}
]