Proposal: Generics Type Arguments of class recognized by class constructor

[pmunin]

It'd be really nice if class constructors could recognize Generic Type Argument for the class. That would allow to instantiate generic classes for Anonymous types much easier without helper methods.

Actual behavior 👎 👎 👎

var myObjectsArray = new[]{ new{ FirstName: "John", LastName:"Smith"} };
var myObjsQueue = ToQueue(items);

Queue<T> ToQueue<T>(this IEnumerable<T> items)
{
      return new Queue<T>(items);
}

Desired behavior 👍 👍 👍

var myObjsQueue = new Queue<>(new []{ new {FirstName:"John", LastName:"Smith"} });

Another examples of Desired behavior where it could be sweet 🍬 🍰 🍯

var myLazyObj = new Lazy<>(()=>{ 
        var data = DownloadAndCacheData().Wait();
        return new {FirstName:data["firstName"], LastName:data["LastName"]};
}

var myTupleObj = new Tuple<,>("myLazyObj", myLazyObj);

var myDictionary = new Dictionary<,>(){
   {"person1" , new {FirstName:"John", LastName:"Smith"} }
};

Additional nice-to-haves ⭐ ⭐ ⭐

• Smart As/Is operator recognition:

var myDictionary = new Dictionary<,>(){
   {"person1" , new {FirstName:"John", LastName:"Smith"} }
};
var readOnlyDictionary = myDictionary as IReadOnlyDictionary<,>;

Potential issue: class can implement multiple interfaces with different generic types e.g.:
MyCustomDictionary: IDictionary<string, T> and IDictionary<object,T>

Potential solution: for that situation return compilation error, something like "Cannot do inference of generic type arguments, because unambiguous...".

• Local Type alias for anonymous type or "guessed" generic type arguments
  Created separate issue Proposal: Local Type Alias for anonymous types #430, but specifics for this issue could be "guessed" generic type argument:

var myDictionary = new Dictionary< ,<TPerson> >(){
   {"person1" , new {FirstName:"John", LastName:"Smith"} }
};

var persons = new List<TPerson>(myDictionary.Values);

[svick]

This looks like a duplicate of #151.

[pmunin]

It does look similar, however I believe definition in this issue is more clean and straightforward. Am I bias? 😄