Playground bug when aliasing @id

[lanthaler]

If I alias @id expansion produces some strange outputs in the playground when @id is used in the JSON-LD document. It nests an @id within @id, see http://bit.ly/zKljJE

{
    "@id": {
        "@id": "#me"
    },
    "http://xmlns.com/foaf/0.1/knows": [{
        "@id": {
            "@id": "http://example/bob#me"
        },
        "http://xmlns.com/foaf/0.1/name": "Bob",
        "http://xmlns.com/foaf/0.1/homepage": {
            "@id": "http://example.com/bob"
        }
    }, {
        "@id": "http://www.markus-lanthaler.com/#me",
        "http://xmlns.com/foaf/0.1/name": "Markus",
        "http://xmlns.com/foaf/0.1/homepage": {
            "@id": "http://www.markus-lanthaler.com/"
        }
    }]
}

"@id": "http://www.markus-lanthaler.com/#me" is correct as I used @iri in the input document.