Version: Haxe 3.2.0 release. Desc: In JS, Haxe essentially reifies the type for generic functions and the following code will work without issue and output "1" three times.

TypedReturns.hx

class Holder
{
    public var components = new Array<Dynamic>();
    public function new() {}
    public function getFirst<T>():T
    {
        return cast components[0];
    }
}

class Test {
    static function main() {
        var holder = new Holder();
        holder.components.push(1);
        var result:Int = holder.getFirst();
        var result2:Dynamic = holder.getFirst();
        var result3:Bool = holder.getFirst();
        trace(result);
        trace(result2);
        trace(result3);
    }
}