C#: Any way to suppress compiler errors similar to suppressing warning messages?

Question

I have the following code that generates a compiler error:

    Boolean IConvertible.ToBoolean(IFormatProvider provider)
    {
        ThrowHelper.ThrowInvali         


        

Answer 1

A simple brain exercise why the requested feature could lead to problems. Imagine that ThrowHelper.ThrowInvalidCast is defined in some 3rd-party library. You might know that the method always throws and tell the compiler about it or a very advanced static analyzer might be able to determine that the method always throws at the moment the code is compiled.

Now some other developer deploys an updated version of that library. Now the method doesn't always throw. All of a sudden, there is a case that your method has no return path. Just to handle that case the compiler (or the runtime) would have to include a backup plan what to do in such a situation. Quite a lot of overhead for something that can easily be fixed by writing correct code.

UPDATE: Theoretically, C# could be extended to allow for methods with no return path. Eric Lippert mentioned that in a comment to Jon Skeet's answer here:

A "never" method would simply be a void method that is not allowed to have a reachable end point or any return statements. That solves the problem at compile time. At runtime, it's the verifier's responsibility to ensure that methods actually implement their return type semantics correctly; the verifier could similarly determine that there are no return instructions and that the end point is not reachable.