incorrect type generated when combining oneOf with properties

[tannera-cargill]

Description

This library is incorrectly generating TypeScript types for OpenAPI schemas that combine oneOf with properties. The generated type only includes the oneOf union, ignoring the additional properties defined in the schema.

OpenAPI specification (optional)

{
  "CompositionWithOneOfWithRefAndPropertiesFlat": {
    "type": "object",
    "oneOf": [
      {
        "$ref": "#/components/parameters/SimpleParameter"
      },
      {
        "$ref": "#/components/schemas/NonAsciiStringæøåÆØÅöôêÊ字符串"
      }
    ],
    "required": [
      "baz",
      "qux"
    ],
    "properties": {
      "baz": {
        "type": "integer",
        "format": "uint16",
        "minimum": 0.0,
        "nullable": true
      },
      "qux": {
        "type": "integer",
        "format": "uint8",
        "minimum": 0.0
      }
    }
  }
}

Expected behavior
The generated TypeScript type should be an intersection of the oneOf union and an object type with the additional properties. Something like:

export type CompositionWithOneOfWithRefAndPropertiesFlat = 
  (ParameterSimpleParameter | NonAsciiStringæøåÆØÅöôêÊ字符串) 
  & {
    baz?: number;
    qux: number;
  };

Actual behavior

export type CompositionWithOneOfWithRefAndPropertiesFlat = ParameterSimpleParameter | NonAsciiStringæøåÆØÅöôêÊ字符串;

Configuration

No response

System information (optional)

No response

[mrlubos]

Thanks for reporting @tannera-cargill