c# - Dictionary and Items protected members of a KeyedCollection in Unity3d 5.3.1? -

i've been using unity 5 year , worked fine until last week when had idea update our ide 5.3.1 version.

now compiler shows 2 errors:

the name `dictionary' not exist in current context. name `items' not exist in current context. 

both localized in simple keyedcollection

public class commandprocessqueuecollection : keyedcollection<int, commandprocessqueue> {    public bool trygetqueue(int id, out commandprocessqueue queue)    {        if (dictionary != null)        {            return dictionary.trygetvalue(id, out queue);        }         foreach (var in items)        {            var k = getkeyforitem(i);            if (comparer.equals(id, k))            {               queue = i;               return true;            }        }        queue = default(commandprocessqueue);         return false;    }     protected override int getkeyforitem(commandprocessqueue queue)    {       return queue.id;    } } 

after several attempts things became more tricky exact same code has been compiled in 5 different machines 5.3.1 installed.

well, 2 out of 5 proved compile without error.

furthermore, msbuild seems compile code without error well.

probably, there differences, among machines, in .netframework used mono compilations.

do have idea odd issue?

ps: i'm adding using system.collections.objectmodel , current api compatibility option in unity editor set .net 2.0.

ok, team solved.

in machines windows support editor 5.3.1f1 not installed therefore standard module of webplayer running , few api of .net not available.