Papercut: duplicate type names do not cause an error when building a Schema object

Start at Schema(schemaType), using the Define.Object and Executor entry points shown in the reproduction. Trace how the schema collects named types and determine where duplicate names are accepted. Done means constructing the schema fails for the two Book definitions, with the reproduction or a focused validation check confirming the error occurs before execution.

This script demonstrates the issue:

#r "nuget: FSharp.Data.GraphQL.Server, 1.0.7"

open FSharp.Data.GraphQL
open FSharp.Data.GraphQL.Execution
open FSharp.Data.GraphQL.Types

type Book =
  {
    Title : string
    Year : int
  }

let bookType1 =
  Define.Object(
    name = "Book",
    description = "Book type 1",
    fields =
      [
        Define.Field(
          "title",
          String,
          fun ctx (x : Book) -> x.Title
        )
      ]
  )

let bookType2 =
  Define.Object(
    name = "Book",
    description = "Book type 2",
    fields =
      [
        Define.Field(
          "title",
          String,
          fun ctx (x : Book) -> x.Title
        )
        Define.Field(
          "year",
          Int,
          fun ctx (x : Book) -> x.Year
        )
      ]
  )

let schemaType : ObjectDef<unit> =
  Define.Object(
    name = "Query",
    fields =
      [
        Define.Field(
          "books1",
          ListOf bookType1,
          fun _ () -> []
        )
        Define.Field(
          "books2",
          ListOf bookType2,
          fun _ () -> []
        )
      ]
  )

let schema = Schema(schemaType)
let executor = Executor(schema)

let query = """
{
  books2 {
    title
    year
  }
}
"""

let result =
  executor.AsyncExecute (query)
  |> Async.RunSynchronously

let output, errors =
  match result.Content with
  | GQLResponseContent.Direct (output, errors) -> output, errors
  | x -> failwith $"Unsupported: %A{x}"

printfn $"Output:\n%A{output}\n"

for error in errors do
  printfn $"Error:\n%A{error}\n"

Output:
map []

Error:
("Field 'year' is not defined in schema type 'Book'.", ["books2"; "year"])

The two book types share a name, and the library silently picks bookType1.

I think that duplicate names should cause schema building to fail, so that this error is caught earlier.

let schema = Schema(schemaType) // Should raise an exception on an invalid schema

Any thoughts?