[LLVMdev] Iterator issue in BranchFolder::RemoveBlocksWithHash?

[Stefanus Du Toit]

On 27-May-08, at 5:48 PM, Mike Stump wrote:
> 4 Effects: Invalidates iterators and references at or after the point
> of the erase.
>
>> In any event, I'm not arguing that this ought to work, just that the
>> (current) standard is badly worded.
>
> I think it was a bug in the original language standard.  You can ask
> Howard, if you're curious.

There's a proposed resolution to fix this:

http://std.dkuug.dk/jtc1/sc22/wg21/docs/lwg-active.html#414

===
Proposed resolution:

In 23.2.4.3 [lib.vector.modifiers] paragraph 3, change "Invalidates  
all the iterators and references after the point of the erase" to  
"Invalidates iterators and references at or after the point of the  
erase".

Rationale:

I believe this was essentially a typographical error, and that it was  
taken for granted that erasing an element invalidates iterators that  
point to it. The effects clause in question treats iterators and  
references in parallel, and it would seem counterintuitive to say that  
a reference to an erased value remains valid.

===

Stefanus