I learn something new about C# every day. This is a subtle and tricky language. Pop quiz: foo is of a type which has a base class which has made a normal, everyday virtual override of System.Object.ToString . There are no additional overrides, hides...

I haven't forgotten that I promised to describe one more place where we insert an explicit conversion automatically. But before that, a quick digression. Reader Phil Haack has written some good tips for writing clear code and quotes an old post of...

Jeroen Frijters knew the answer to my challenge of last time: how is it that Foo foo = new Foo(); can cause a runtime conversion failure? And how is it that Bar bar = (Bar)(new Baz()); can succeed even if there is no user-defined conversion or built-in...

Reader Larry Lard asks a follow-up question regarding the subject of Monday’s blog entry . Why is it that the compiler knows that (int)(new Base()) will always fail, and therefore makes the conversion illegal, but does not know that (Derived)(new Base...

Reader Niall asked me why the following code compiles but produces an exception at runtime: class Base {} class Derived : Base {} class Castable { public static explicit operator Base() { return new Base(); } } // ... Derived d = (Derived)(new Castable...

I've been meaning to write a blog post about a recent design change that we've made here on the C# team. As you may have gathered from my previous posts, we are introducing anonymous tuple types in C# 3.0. We've recently decided to make instances of those...

Yesterday I posed a slightly harder version of the puzzle I posted the day before . Reader Steve found a solution: public class C : A {} public class A { public class D : C {} } See his comment for the trace of the logic that shows why this asserts...

Reader RichM found the same solution to the puzzle I posed yesterday that I did: public class V : S.T {} public class S { public class T{} } The control flow of the emitter from the start to the point of the bug goes like this: Emit(V) Emit ...

I don’t know why but for some reason I find this little recursive algorithm I ran across in the compiler the other day to be completely hilarious. For every class in your program we have to emit metadata. For various historical reasons, there are strict...