aliasRefs creates a circular reference

[vogre]

Example files: a.ts

export interface X {
  a: string;
}

export interface Y {
  x?: X;
}

tsconfig.json

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "strict": true,
    "esModuleInterop": true
  }
}

Command line:
typescript-json-schema tsconfig.json "*" --required --ignoreErrors --refs --aliasRefs

Generates

"X": {
            "$ref": "#/definitions/X"
},

Possibly related to #246 as this will blow up the stack when used.

Possible workaround: specify as x: X | undefined instead of x?: X.