.NET Compiler Platform ("Roslyn") analyzer to disallow calling object.ToString() on types lacking an override.

Imagine we have the following simple POCO for representing money:

struct Money {
    public decimal amount;
    public string currency;
}

Then we try to print out an instance of it:

System.WriteLine("I need about {0}", new Money { amount = 3.50m, currency = "$" });

The statement will print I need about Money, which is not very useful. This came up a number of times on a team when writing code logging the state of objects for debugging purposes, leading to the creation of this analyzer.

After installing this analyzer the above WriteLine call will result in a compile-time error message Expression of type 'Money' will be implicitly converted to a string, but does not override ToString().