Why is mangling different for separate compilation?

[Atila Neves via Digitalmars-d]

On Saturday, 27 February 2016 at 10:18:53 UTC, Joakim wrote:
> On Saturday, 27 February 2016 at 09:11:02 UTC, Atila Neves 
> wrote:
>> On Saturday, 27 February 2016 at 03:51:00 UTC, Walter Bright 
>> wrote:
>>> On 2/26/2016 4:45 AM, Atila Neves wrote:
>>>> '_D3bar16__unittestL2_531FZv'
>>>> '_D3bar14__unittestL2_1FZv'
>>>
>>> It uses a sequence number to generate different ids for the 
>>> unit tests. In the former, it's the 531st unit test, the 
>>> latter, the first.
>>
>> In both cases though, there's only one unit test. The only 
>> difference is how the files were compiled.
>
> 531 is the number across all modules, because they weren't 
> separately compiled.

Which "all modules"? Phobos? druntime? The only `import` in that 
code is `import bar;`.

Atila