WARNING: Cannot determine if container access is using container type

Sigh....  Worked it out.... umb-da.

Key change:

w = Weather.getHourlyForecast() as Array<HourlyForecast>;

function test() as Void{
	var w, ti, sz = 6;

	w = Weather.getHourlyForecast() as Array<HourlyForecast>;
	if (w != null) {
		for (var j=0; j<sz; j++) {
			ti = Gregorian.info(w[j].forecastTime as Moment, (Time.FORMAT_LONG as DateFormat));
		}
	}	

}	

I have the exact same warnings in my compiler. On code like this (this is an onreceive callback from a webrequest):

    function onReceiveRooms(responseCode as Lang.Number, data as Lang.Dictionary or Lang.String or Null) as Void {
   		Log("onReceive responseCode="+responseCode+" data="+data);
       // Check responsecode
       if (responseCode==200)
       {
       		// Make sure no error is shown
           	// ShowError=false;
           	if (data instanceof Dictionary) {
				if (data["status"].equals("OK")) {
	            	if (data["title"].equals("getplans")) {
						if (data["result"]!=null) {
                            Log("Getting the rooms");
							roomItems={};
							for (var i=0;i<data["result"].size();i++) {
								roomItems.put(data["result"][i]["idx"], new WatchUi.MenuItem(data["result"][i]["Name"], null, data["result"][i]["idx"],{}));

The compiler doesn't know what type is data["result"], data["result"][i]

You can tell it using "as"

And what would that look like in coding?

I don't know, it's your data... You can try something like:

in the function declaration:

data as Lang.Dictionary<String, Array<Dictionary<String, String or Number>>> or Lang.String or Null

If that doesn't work then you can also do it here, but it's uglier:
roomItems.put(((data["result"] as Array)[i] as Dictionary)["idx"], ... ;

also see: forums.garmin.com/.../the-road-to-strict-typing-is-paved-with-good-intentions

The error tells you what it''s looking for. Copy/paste it into a typedef and use that. It will change with SDK versions, so it will be easier to maintain this way too.

//do this up top
//typedef webData as Null or $.Toybox.Lang.Dictionary or $.Toybox.Lang.String; // SDK 6.2
typedef webData as Null or $.Toybox.Lang.Dictionary or $.Toybox.Lang.String or $.Toybox.PersistedContent.Iterator; // SDK 6.4+
// then in the function
public function onReceiveNearest(response as Number, data as webData) as Void {

I don't think that will change anything. He already has Dictionary in the function declaration. The error is not from there, it's where he's indexing the dictionary and it's sub structures, because it doesn't know what type is data["result"], ...

For the elements assign them to their own variable and type it at that point. The compiler doesn't seem to handle nested array and dictionary elements very well.

var rooms = data["results"] as Array<String or Number or Array<Float> >; // or whatever the type is

Then use the variable instead of the top level element. It will be faster and use less memory, too. Keep doing this for each level you need to drill down to so in your for loop you should have something like:

var room = rooms[i] as < whatever this type is>;

Then use the room["idx"] in your put statement.

data is a json object (converted to monkey c by monkey c itself). I cannot change the definition because it's declared in the OnReceive callback method and then i get other errors.

However with a little workaround by declaring another var it worked (bit strange to include extra vars to supress typecheck warnings, but hey if it works it works):

'cause the problem is the Levels[...]