Question

Say I have two methods, one calls the other. The second method has code that will generate a compile time error. Since it’s not called, why does the compiler still bother to process it?

void method1()
{
    var i = 1;
    //method2();
}

void method2()
{
    int i = "2";
}

Answer 1

You can’t be sure that someone else won’t call that method at runtime using reflection. Your code MUST compile or it’s not valid code – if it’s never used… comment it out!

To expand on this:

Basically at compile time you are strongly typed – .NET will type check everything to ensure that what you are trying to do is legal, however, you can still throw exceptions at run time due to null references, bad casts etc etc.

Reflection is a component of the .NET framework that allows a developer to inspect the properties/fields/methods etc of an assemblies types via the assembly metadata

Reflection allows runtime type discovery and inspection of these types, it also allows invocation of methods/properties and modification of fields etc. (You can even create new generic types at runtime or completely new types altogether).

In other words, you can’t guarantee that code you think won’t be called, isn’t called somewhere else at some point. For reflection to be possible, every bit of code needs to be valid and compilable

Whether that code will succeed at runtime is another story – but that’s why we have exception handling.