Object variable not set

[retailcoder]

This code compiles:

Sub DoSomething()
    Dim foo As Object
    foo = 42
End Sub

As does this code:

Sub DoSomething()
    Dim foo As MyClass
    foo = New MyClass
End Sub

And this code:

Sub DoSomething()
    Dim foo As Collection
    With foo
        .Add 42
    End With
End Sub

Both will result in runtime error 91 - object or with block variable not set, a very common VBA programming error.

As of version 1.3, Rubberduck has everything needed to detect these anomalies, and warn about them. Let's implement a code inspection for it.

[retailcoder]

This inspection needs to be implemented for 2.0.