On 2016-08-30 12:11, Eli Zaretskii wrote:
>> From: Clément Pit--Claudel <clement.pit@gmail.com>
>> Date: Tue, 30 Aug 2016 11:23:31 -0400
>>
>> I didn't realize that these functions needed widening. Its documentation doesn't seem to mention it, nor its docstring. What about the attached patch?
> 
> This is not specific to these functions, this is a universal rule in
> Emacs: if you want to access a buffer position, you need to make sure
> it's in the accessible region.

Ok; I wasn't aware of this rule.  The documentation of buffer-substring mentions the error, so I though the patch would be useful.

Clément.