vibe-d-0.8.0 tree structure serialization still a problem

[tchaloupka]

With #1673 closed/merged there is still a problem with the tree structure safety serialization after further tuning which isn't catched by the unittests.

Try for example:

@system unittest {
	import vibe.data.json;
	static struct Bar { Bar[] foos; int i; }
	auto b = deserializeJson!Bar(`{"i":1,"foos":[{"foos":[],"i":2}]}`);
	assert(b.i == 1);
	assert(b.foos.length == 1);
	assert(b.foos[0].i == 2);
}

It fails with:

data/vibe/data/serialization.d(658,24): Error: function vibe.data.json.JsonStringSerializer!(string, false).JsonStringSerializer.readArray!(Traits!(Bar[], DefaultPolicy)).readArray(scope void delegate(ulong) @safe size_callback, scope void delegate() @safe entry_callback) is not callable using argument types (void, void delegate() @system)
data/vibe/data/serialization.d(567,108): Error: template instance vibe.data.serialization.deserializeValueImpl!(JsonStringSerializer!(string, false), DefaultPolicy).deserializeValueDeduced!(Bar[]) error instantiating
data/vibe/data/serialization.d(764,48):        instantiated from here: deserializeValue!(Bar[])
data/vibe/data/serialization.d(749,31):        instantiated from here: __lambda2!string
data/vibe/data/serialization.d(567,108):        instantiated from here: deserializeValueDeduced!(Bar)
data/vibe/data/serialization.d(299,69):        ... (2 instantiations, -v to show) ...
data/vibe/data/json.d(1436,48):        instantiated from here: deserialize!(JsonStringSerializer!(string, false), Bar, string)
data/vibe/data/serialization.d(1899,30):        instantiated from here: deserializeJson!(Bar, string)
data/vibe/data/serialization.d(749,30): Error: function vibe.data.json.JsonStringSerializer!(string, false).JsonStringSerializer.readDictionary!(Traits!(Bar, DefaultPolicy)).readDictionary (scope void delegate(string) @safe entry_callback) is not callable using argument types (void)