std.data.json formal review

[Suliman via Digitalmars-d]

is the current build is ready for production? I am getting error:

source\stdx\data\json\value.d(81): Error: safe function 
'stdx.data.json.value.JSONValue.this' cannot call system function 
'std.variant.VariantN!(12u, typeof(null), bool, double, long, 
BigInt, string, JSONValue[], 
JSONValue[string]).VariantN.__ctor!(typeof(null)).this'