Issue with Spread Syntax and Field Return Type Override in GraphQXL

[ruchib30]

We are using interface hierarchies extensively in our GraphQL schema and encountered an issue with GraphQXL when attempting to override a field's return type in a type implementation. According to the GraphQL specification, it is valid for a field in an implementing type to override the return type of the interface field with a more specific type, provided the new type implements the original return type. However, GraphQXL fails to compile when the spread syntax (...) is used, even though this is spec-compliant.

Example Schema:

# Definition of an interface
Interface I1 {
}

# Definition of a type that implements the interface
Type T1 implements I1 {
}

# Interface with multiple fields, including a field of type I1
Interface Base {
  field: I1
  # many more fields
}

# Implementation without spread syntax - This works
Type BaseType implements Base {
  field: T1 # Valid as T1 implements I1
  # all other fields of interface Base are manually copied
}

# Implementation with spread syntax - This fails to compile
Type BaseType implements Base {
  ...Base
  field: T1 # Valid as T1 implements I1 but fails compilation
}

Expected Behavior:
The schema should compile successfully, as overriding field with T1 is valid per the GraphQL spec, and the spread syntax should allow inclusion of all other fields from the Base interface without redundancy.

Observed Behavior:
GraphQXL fails to compile when the spread syntax is used, forcing us to manually copy all other fields from the Base interface to ensure compatibility.

Request you to look into this and provide support for above syntax. This would greatly improve maintainability for schemas leveraging interface hierarchies.