Why is this an issue?

Unnecessarily verbose declarations and initializations make it harder to read the code, and should be simplified.

Specifically the following should be omitted when they can be inferred:

• array element type
• array size
• new DelegateType
• new Nullable<Type>
• object or collection initializers ({})
• type of lambda expression parameters
• parameter declarations of anonymous methods when the parameters are not used.

Noncompliant code example

var l = new List<int>() {}; // Noncompliant, {} can be removed
var o = new object() {}; // Noncompliant, {} can be removed

var ints = new int[] {1, 2, 3}; // Noncompliant, int can be omitted
ints = new int[3] {1, 2, 3}; // Noncompliant, the size specification can be removed

int? i = new int?(5); // Noncompliant new int? could be omitted, it can be inferred from the declaration, and there's implicit conversion from T to T?
var j = new int?(5);

Func<int, int> f1 = (int i) => 1; //Noncompliant, can be simplified

class Class
{
    private event EventHandler MyEvent;

    public Class()
    {
        MyEvent += new EventHandler((a,b)=>{ }); // Noncompliant, needlessly verbose
    }
}

Compliant solution

var l = new List<int>();
var o = new object();

var ints = new [] {1, 2, 3};
ints = new [] {1, 2, 3};

int? i = 5;
var j = new int?(5);

Func<int, int> f1 = (i) => 1;

class Class
{
    private event EventHandler MyEvent;

    public Class()
    {
        MyEvent += (a,b)=>{ };
    }
}