assert(obj) is an atrocity

[Alex Rønne Petersen]

Hi,

As the title suggests, I'm going to be rather blunt about this. 
assert(obj) testing the invariant *without* doing a null check is insane 
for the following reasons:

1) It is not what a user expects. It is *unintuitive*.
2) assert(!obj) does an is-null check. assert(obj) is a completely 
broken opposite of this.
3) No AssertError is thrown, which is the entire point of the built-in 
assert().
4) The few added instructions for the null check hardly matter in a 
*debug* build of all things.

I don't mind assert(obj) testing the invariant of obj. In fact, that 
very much makes sense. But please, please, *please* check the object for 
null first. This is a random inconsistency in the language with no other 
justification than "seg faults are convenient in a debugger". By the 
same logic, we might as well not have array bounds checks. However, the 
state of things is that array bounds checks are emitted by default and 
users can disable them for e.g. a release build. I don't see why this 
case is any different.

- Alex