Yes, but any of the passed-in arguments can be null if they are de-referenced without checking, or you can muck up your context by doing something weird.

I'm not justifying buggy code, but these days we do handle more objects-per-debug-line-number than we used to.

Especially in lambda expressions for LINQ methods...

But you can already debug inside lambda expressions. E.g. for

     new string[] { "1", null }.Select(s => s.Length).ToList();

VS has no trouble at all telling me the statement that caused the NRE and I can inspect variables local to the lambda as well.

But you can't always debug code that's out in the wild with the same exact scenario that caused the NRE.

It's helpful to have the actual thing that's null for post-error troubleshooting.

The whole discussion is about a debugger feature, or at least, the runtime groundwork required for said debugger feature. It will not result in the exception message telling you the null reference's name. It enables an attached debugger to query the runtime for additional information to determine that.

It does when it has a bug in it...

> return this

Not necessarily. Take a look at LINQ, for example.

LINQ is not a fluent programming style, LINQ is standard functional programming with higher order functions. Chaining calls back to back isn't what fluent is, chaining calls to the same object back to back is fluent whereas with LINQ each call returns a whole new object or set of objects; these are entirely different things. The fluent style is an attempt to emulate Smalltalk's cascade operator in languages that lack it by returning "this" from setters enabling a chain of setters to be called on the same object: that's all it is. This style has been idiomatic to Smalltalk since the 70's and doesn't require faking it because there's actually a cascade operator.