[JSON] schema fails when additionalItems with oneOf and $ref is used.

[HIAB-vesteel]

When having a schema with additionalItems containing oneOf with $ref the schema gives errors (see comments in input_data.json). When removing $ref and pasting in the schemas validation works as intended.

• VSCode Version: 1.35.1
• OS Version: Windows 10 64-big

Steps to Reproduce:

1. Add files (see below) to empty project
2. See it fail

input_data.json

{
  "$schema": "./BasicType.schema.json",
  "extra_types": [
    {
      "type": "Type_A"
    },
    {
      "type": "Type_B",
      "false_property": "Gives error"
    },
    {
      "type": "Type_B" // Matching multiple schemas
    },
    {
      "type": "Type_A"  // Matching multiple schemas
    },
    {
      "type": "Type_B",  // Matching multiple schemas
      "false_property": "Should also give error"
    }
  ]
}

BasicType.schema.json

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "type": "object",
    "required": [
        "$schema",
        "extra_types"
    ],
    "properties": {
        "$schema": {
            "type": "string"
        },
        "extra_types": {
            "type": "array",
            "items": [
                {
                    "$ref": "./Type_A.schema.json"
                },
                {
                    "$ref": "./Type_B.schema.json"
                }
            ],
            "additionalItems": {
                "oneOf": [
                    {
                        "$ref": "./Type_A.schema.json"
                    },
                    {
                        "$ref": "./Type_B.schema.json"
                    }
                ]
            },
            "minItems": 2
        }
    },
    "additionalProperties": false
}

Type_A.schema.json

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "type": "object",
    "required": [
        "type"
    ],
    "properties": {
        "type": {
            "type": "string",
            "const": "Type_A"
        }
    },
    "additionalProperties": false
}

Type_B.schema.json

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "type": "object",
    "required": [
        "type"
    ],
    "properties": {
        "type": {
            "type": "string",
            "const": "Type_B"
        }
    },
    "additionalProperties": false
}

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• [json] Improve combining schemas not working with 'additionalProperties: false' (#20193)
• Print warning when contributing second search provider for same schema (#59360)
• [json] schema validation should support defining the problem severity (#29527)