Hacker News Reader

I'm not sure I understand the term "illegal operation" here. I would assume it means "an operation that isn't allowed", but in the case anything that is allowed (e.g. using null) would by definition not be illegal. Can you clarify what you mean by this term?

View on HN

Dereferencing null is allowed at compile time but disallowed at run time; that's what makes it an illegal operation.

Ah, so the term in this case is just used to mean "something that cases a runtime error"? I think I misunderstood because the comment I was responding to said "using a null reference", which to me doesn't necessarily imply dereferencing it (although that's open to interpretation of course).

I think s?he means operations that would cause a runtime type error/exception by "illegal"

Reply on news.ycombinator.com