Cannot use enum or union as Record Index type

[grddavies]

Hi,

Great library!

I think I've found a limitation that you cannot use enums and unions as an index for a Record type.

Repro:

Union

type Variant = 0 | "ONE";

type KVMap = {
    0: boolean;
    ONE: number;
};

export type Value = KVMap[KeyType];
//          ^? `string | number`

Expected:

{
  "$ref": "#/definitions/Value",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "definitions": {
    "Value": {
      "type": [
        "boolean",
        "number"
      ]
    }
  }
}

Actual:

 TSJ - 104: Invalid index "0" in type "structure-527321465-39-76-527321465-25-77-527321465-0-115"

8 export type Value = KVMap[Variant];

Enum

enum Variant {
    A = 0,
    B = "STR",
}

type KVMap = {
    [Variant.A]: boolean;
    [Variant.B]: number;
};

export type Value = KVMap[KeyType];
//          ^? `string | number`

Expected:

{
  "$ref": "#/definitions/Value",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "definitions": {
    "Value": {
      "type": [
        "boolean",
        "number"
      ]
    }
  }
}

Actual:

 TSJ - 104: Unexpected type "enum-2098387231-0-42-2098387231-0-150" (expected "LiteralType.js" or "StringType.js" or
 "NumberType.js")

11 export type Value = KVMap[Variant];

I'm happy to try put together a PR for this

[domoritz]

Thanks for the issue and looking into a fix!

[cjlawson02]

+1 on this