graphql query decode error

[WoeOm]

query NFTList($after: String = "1") {
  tokensConnection(
    orderBy: id_ASC
    first: 10
    after: $after
    where: {metadata: {name_isNull: false}}
  ) {
    edges {
      node {
        id
        tokenAccounts(limit: 10) {
          account {
            address
          }
        }
        metadata {
          fallbackImage
          name
        }
      }
    }
  }
}

where: {metadata: {name_isNull: false}} decode error.

The possible reason is that }} is parsed as a widget expression